texts: Why do the sick and unhealthy trees leaf out first in spring?

texts: It's spring. The time of year that trees start to leaf out. I have been watching them, and noticed an interesting pattern. The unhealthy trees of a species leafs out first. I've noticed this especially with the wild black cherries. The hollow and damaged trees and the ones in poor conditions leaf out a week ahead of the good ones. The last ones to leaf out are the strongest in the area. This is not just a casual observation, and I have kept careful track of it. What causes this?


texts: A request for an overview of the cranial nerves

texts:
Is there any resource that contains motor and sensory innervations, or pathways of all the twelve cranial nerves (i.e., cranial nerve I to XII)?

I have found this book chapter on the cranial nerves, but it is too broad for me -  I'm still at high school.


texts: what these suffixes mean,-coel,-blast,-cyst?

texts: in the connective tissue (Bones) we have 3 types  osteoblast, osteocoel,osteocyst what are they and why they differ.


texts: What is the structural difference between beta and gamma globin chains of Hb?

texts:
Hemoglobins are tetramers composed of pairs of two different polypeptide subunits. The subunit composition of the principal hemoglobins are α2β2 (HbA; normal adult hemoglobin), α2γ2 (HbF; fetal hemoglobin) and α2δ2 (HbA2; a minor adult hemoglobin)

The total number of amino acids in beta chain and gamma chain is the same-146. The higher affinity of HbF to oxygen is due to presence of serine(in gamma chain) in place of histidine(in beta chain), which inhibits its binding with 2,3-bisphosphoglyceric acid.

Is this the only difference, or are there more such differences in the amino acid sequence?


texts: Does a specific blood group enhance the Plasmodium growth?

texts:
I am maintaining Plasmodium falciparum cultures for past 6 months. For the blood culture, usually we lab members take turns  and donate blood for the culture. I observed that the parasite's normal growth cycle were fast and more healthy in B+ blood, little slow in AB+ blood. But on the whole the culture was maintained good but I really observed fast stage transitions in B+.

Is this really possible? Does a specific blood group have an impact on Plasmodium growth? Did anyone notice the same issue?

Thanks.


texts: In organism that have a preformed germ-line like Drosophila where germ cells are pre-allocated in the oocyte, are there technically no adult pluripotent stem cells since germ line cells can't be developed from somatic stem cells?


texts:
I've seen some articles which came in contradiction with each other.

The first article was talking about flying dinosaurs, dinosaurs with feathers and so on.

A couple of other articles are talking about misconceptions about dinosaurs one of them being that there are no flying dinosaurs but just flying reptiles (from scholastic.com and livescience.com).

So, which one is right?
Also if possible please provide a source for argument.

I cannot find the first article again.


texts: what is the function of satellite in a chromosome?

texts: What is the specific function of a satellite in a chromosome ? How are sat-chromosomes different from others ? On molecular basis, what are the functional advantages of it ?


texts: Why are de novo genetic mutations usually NOT inherited?

texts:
I am told de novo genetic mutations (germ mutations in either parent's sperm or egg cell, or the newly fertilised egg) are not usually inherited, and do not contribute to heritability.

It would seem to me that, intuitively, a de novo mutation would be passed from the affected individual (assuming they survive and are fertile) onto offspring, just like any other inherited mutation. But apparently not.

Why is this?


texts: As I understand, vaccination helps the human body to create antibodies and stimulate immune system to react against specific antigens. If someone gets sick, do vaccines help to stimulate immune system? If so, do we vaccine sick people for some specific disease?


texts: What will happen to a neuron if I suddenly remove the pump but not the leaky Na+ and K+ channels?

texts:
K+ is more abundant inside the cell and thus has a propensity to move outwards. It has an equilibrium potential of -80 mV. Na+ is more abundant extracellularly and thus has a propensity to move inwards. It has an equilibrium potential of 58 mV. The resting membrane potential of a cell is about -70 mV. So, K+ moves out (more towards its equilibrium potential) and Na+ moves in (more towards its equilibrium potential). The pumps throw out the Na+ and bring back in K+ thus maintaining their concentration and hence the membrane potential.

Now if I suddenly remove the pump from the cell, what would happen? Will the cell moves towards K+'s equilibrium potential or towards Na+'s equilibrium potential? I know that the answer is that the cell will discharge and have a membrane potential of 0 mv, but I don't understand why.


texts:
I have got 6 pet fishes in an algae ridden  tank.  My plan is to place the tank completely away from sunlight so the algae dies.  How would this affect my fish?
Edit: Just checked all my fishes died today.  Either its the lack of light or just that i forgot to add the chlorine removal or water pump.


texts: Does retinal detachment happen more frequently at night?

texts: My understanding and experience is that during the night photoreceptors are less tightly coupled to the retinal pigment epithelium.  Does this make it more likely for a retinal detachment to happen at night?


texts: The replicator equation vs the Lotka-Volterra equation

texts:
Background

The replicator equation with $n$ strategies is given by the differential equation:
\begin{equation}
  \dot x_{i} = x_{i} \left( \sum_{j=1}^{n} a_{ij}x_{j} - \phi \right)
  \qquad i = 1, \ldots, n
\end{equation}
where $x_i$ is the frequency of the strategy $i$, $A=[a_{ij}]$ is the payoff matrix, and $\phi$ is the average fitness of the population. Basically, what the replicator equation is saying is that the rate of increase of the strategy $i$ (i.e., $\dot x_i/ x_i$) is the difference between the fitness of $i$ (i.e., $\sum_{j=1}^{n} a_{ij}x_{j}$) and the average fitness $\phi$ of the whole population.

The Lotka-Volterra equation with $n-1$ species is:
\begin{equation}
  \dot y_{i} = y_{i} \left(r_{i} + \sum_{j=1}^{n-1} b_{ij}y_{j}\right) \qquad
  i=1, \ldots , n-1
\end{equation}
where $y_i$ is the abundance of species $i$, $r_i$ the intrinsic growth rate, and $b_{ij}$ describes how the species $i$ and $j$ interact (wiki entry on the Lotka-Volterra eqn).

According to Nowak's book Evolutionary Dynamics, these two equations are equivalent to each other (the same result appears in Hofbauer and Sigmund's Evolutionary Games and Population Dynamics). This is a neat result because it shows that results in ecology based on the Lotka-Volterra equation has a game theoretic interpretation and vice-versa.

Question

This would mean that the replicator equation for two strategies (e.g., the Hawk-Dove game) is equivalent to a single species interacting with itself under the Lotka-Volterra equation. How could that be? The replicator equation would describe the frequency of two strategies in the population, but the equivalent Lotka-Volterra equation would describe the evolution of a single and undifferentiated population. My problem is not so much with the proof of the equivalence between these two equations (Hofbauer and Sigmund give a proof of this equivalence in their book), but with the interpretation of the equivalence between the two eqns.


texts: What is this blue-green bioluminescent jellyfish I saw at Aquarium of the Pacific?

texts:
I took this picture of an animal in the bioluminescent section of Aquarium of the Pacific in Long Beach, California, but I neglected to write down what it was.  I've searched the Aquarium's web site, but it doesn't appear to have information about the individual species on exhibit.  (Or else I just can't find it.)  I've also looked at Wikipedia and Google Images, but can't seem to find a creature that looks like this one.

I suspected it could be a jellyfish, and the answer below confirms that.  But I'd like to know what species of jellyfish it is.  (Either common name or scientific name.)


texts: How are ions 'pumped' across a membrane during electron transport?

texts: A number of sites (including this one) that provide descriptions of photosynthesis state that high energy electrons 'pump' ions across a membrane. What is the actual 'pumping' mechanism? I've looked at Wikipedia and at a number of YouTube lectures/tutorials but so far have only found statements as to the where and when but not the how of this important process.


texts:
Why is it that when a bee stings, a little area around it gets swelled?

I think it is some sort of defense mechanism of the body.  But how does it help?


texts: Currency metabolites vs. current metabolites: What's the right term?

texts: I have seen the two terms currency metabolite and current metabolite used interchangeably. Is there a consensus on which is the right term?


texts:
Atmosphere has partial pressure of oxygen as 160mmHg but it's 105mmHg in alveoli, and the partial pressure of carbon dioxide in atmosphere is 0.3mmHg but it's 40mmHg in alveoli.
How is the difference maintained, and can I know the mechanism behind it?


texts: Could anyone kindly identify this bug for me? Is it harmless?

texts:
Details:

Found by a wall/window in Brooklyn, NY in a house not too far from the beach
Rooms walls/windows are dusty and spots of mold growing on wall/windows
size of bug: 2 milimeters

Keywords I've tried in my web search and image search:

True bugs, ticks, types of house bugs, sowbug, stink bugs, insects that live/grow near mold, flat bugs, dust bugs

Any suggestions or ideas would be greatly appreciated.


texts: Is (are) there any crucial gene(s) for the formation of flower in flowering plants?

texts:
I am interested in qualitative (flowers of some plants have petal or sepal, but some plants have not) and quantitative (number of flowers of plants) differences between flowers of different plants.
Formation of flower in flowering plants is under control of which genes?
Which genes are the most important ones in flower development, for example which gene tell the flower that you should have for example 2 stigmas. or which genes tell the plant that you should have 4 flowers or your flowers will not have sepal...
Thank you


texts: If biological enzymes (protease,amylase,lipase etc.) just speed up the reaction (in the digestion process), then what actually digests the food?? (I'm a secondary student)


texts: How many RNA-binding proteins can simultaneously bind on a single mRNA?

texts:
Typically, how many RNA-binding proteins can simultaneously bind to a single mRNA?
Or said differently, how many "binding sites" does an mRNA have?
What order of magnitude?

I am interested in RNA granules like stress granules or P-bodies. They contain, inter alia, mRNA and RNA-binding proteins. I am not a biologist and I didn't come across this information so far in the related literature.


texts: Is it safe to consume foods that are hot enough to scald your skin if you touch it with your hands?

texts:
Coffee is usually served at temperatures that would burn your hands if it spilled on it.

Is the inside of your mouth not affected by the same biological process as that which causes your skin to burn?


texts: Is it possible to obtain single strands of DNA in solution?

texts: Being that it is relatively simple to extract DNA from a variety of sources, what further technique can be used to separate the two complementary strands in solution?


texts: Comparison of gene expression time series in vitro and in vivo

texts:
I have to analyse two datasets consisting of time-series measurements of gene expression. One set are in vivo data from the expression profiles obtained between a few days before birth to several days post-partum. The second data set was obtained in a C2C12 cell line, where t = 0 was defined as the day in which 100% confluence was reached.

Is there an optimal way to align the two time series? Simply aligning the two series using the two t= 0 samples as starting point seems arbitrary.


texts: What type of movement is "spontaneous movement" if it isnt reflex movement and it isnt purposive movement?

texts:
According to Spontaneous and induced fetal activity

  Spontaneous motor activity of the foetus depends significantly ot the
  foetal age; during the period between the 12th and 16th week it was
  recorded in 94.4%

By spontaneous, correct me if I wrong, I understand non reflexive movement and by induced I understand reflexive movement, since

  A reflexive reaction or movement occurs immediately in response to
  something that happens.

But also, according to this other article Fetal movement

  purposive movement begins at about 18 weeks, gradually replacing
  reflex movements

If "spontaneous movement" it isnt reflexive movement since it isnt an automatic reaction to something, and it isnt purposive movement, what is it exactly, and what does it generate it?


texts: Streamside plant identification - Oregon

texts: This is in the western cascades forest in Oregon. Leaves are at the ends of branches only, lives mostly in slightly muddy areas next to streams. Produces small black berries.


texts: What anatomical structures do baleen whales use to vocalize? How does this differ between species?


texts:
I found a dead millipede lying on the ground in Wayand, Kerala (India). I put it in a bottle and brought it home. After around 5 hours a worm came out of it. It is about about 1.5 cm long and segmented.
Any idea if its a larva of some sort?

Edit:
It's been about five days since I posted the picture of the larva , and it seems to have pupated last night. The pupa is approximately 0.5 cms in length. All that's left is to see what happens next.


texts: What is autophagy? How and under which circumstances is it used by the cell? I believe The reason for autophagy is some kind of recycling, am I right? But why does it occur in infections?


texts: How do our smell receptors detect and tell apart exhaust or cigarette smoke, or other man-made chemicals?

texts: Somehow we can tell apart exhaust gas and cig smoke, yet neither of those would have existed when we evolved. How is it that we can sense chemical compounds that we've only synthesized recently?


texts: Can turkeys run around when their head is cut off like chickens do?

texts: Chickens may run around after their head is cut off if the head is severed near the base of the skull leaving the brain stem intact and missing the jugular vein.  This usually only lasts for a few minutes, however there is the case of Miracle Mike that survived for 18 months after his head was cut off.  Do turkeys also exhibit this same behavior and if not, what makes this possible in a chicken but not a turkey?


texts: Can any one reaction in a cell be at equilibrium?

texts:
I know that metabolism as a whole can never be at equilibrium (otherwise the cell is dead !) but I wonder whether a few reactions in the cell could be at chemical equilibrium at a  given point of time.

Is it possible theoretically ? Is there any real example ?


texts: Equation relating probability of fixation and number of generations

texts: I am trying to find an equation that relates the variables of probability of fixation and generations. Or, how does number of generations affect the probability a gene will fix, if population size doesn't significantly decrease or increase.


texts: If a blocker prevents repolarization, will the neuron be stuck in a depolarized state forever?

texts:
Potassium channels help to repolarize the cell after depolarization. But if the potassium channels are blocked, potassium ions cannot flow out of the cell to increase the membrane potential. Thus, one would expect that, at least for some period of time, the cell would be "stuck" in a depolarized state.

How long can this state last? Can a neuron go on indefinitely in a depolarized state if potassium ion channels are blocked? Will it find some other way to depolarize the cell? Will the cell die?


texts:
Are Sloth tongues soft or rough?

Dogs have soft tongues, while cats have rough tongues, so the feeling when they lick e.g. a human hand is quite different. So what about sloths?

This question came up in a recent discussion but I was unable to find any materials as google queries for sloth tongues leads to tons of cute pictures.


texts:
Here is the question:

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she moves the promoter for the lac operon to the region between the beta galactosidas gene and the permease gene which of the following would be likely?

Here is the answer:

Beta galactosidase will be produced.

My question to you is: why is this so? I have no idea where this conclusion came from.
Thanks.


texts:
I am quite confused about nondisjuction in anaphase II. If the double chromosome is not segregated, isn't it double. On pictures they are drawn as single but I don't understand why, and if they are double do they duplicate themselves in the S phase?

What is confusing me in picture above is cell (n+1) , why are all chromosomes single? I thought, after end of division in the third cell (labeled as n+1) there should be 3 chromosomes with single chromatid,  and 1 chromosome with 2 chromatid joined at centromeric region, as it is drawn in picture above that show nondisjunction in cell during anaphase ii . When and how do these 2 chromatids get physically separated?


texts: Insect Egg Case, and if so, What Insect?

texts:
Observed this object today (early October) in Sabino Canyon, on the north side of Tucson AZ, in a riparian area.  It's attached to a mesquite tree (Prosopis spp).  It's attached to one side of the branch, it does not wrap around the branch.  About 1.5 - 2 cm along the maximum dimension.

Looks like some kind of insect egg case and I'm curious if anyone can confirm and knows the insect.


texts: Calculate growth rate of a population by Leslie matrix

texts: We can calculate growth rate of a population by calculate the dominant eigen value of a Leslie matrix. What does this growth rate mean? I think that the growth rate N(t+1)/N(t) is depend on the age structure of N(t)? If the growth rate of a population is less than 1, will the population go extinct?


texts: Expression of red and green fluorescences in the same tissue

texts:
In this article (https://jcs.biologists.org/content/122/14/2351), especially in Figures 1 and 2, they show the expression of GFP and red fluorescence in the same tissue, and I feel like that red fluorescence is present where GFP is expressed (though weaker than where GFP is absent), but I wonder why it's not yellow? Usually, when these two are expressed in the same cells (in this case, GFP is in cytoplasm and red indicates a membrane protein), the yellow color is observed, not like this. In this article, I feel like I see some red below green if that makes sense...

If anybody knows what this means, please give me some advice!
Thank you.


texts: Does anybody recognize this picture and can tell me what organ it came from?


texts: How can skeletal muscles in the human body be modeled as levers?

texts: From what I understand, human arms can be thought of as third class levers, so that the distance from your elbow to the place where the muscle attaches is effectively the distance to the fulcrum, so that arms produce proportionally less strength on the end, and proportionally greater distance when lifting a load.  So this is somewhat of an anatomy question (although I suppose if it was to be used for an exoskeleton, it could be robotics) but can leg muscles and the muscles that attach to the ends of arms and legs be roughly modeled in such a way?  What muscles/muscle groups don't classify that way?


texts: There are various software for simulating reads for Next Generation Sequencing. Can anyone tell what exactly is done by a read simulator software


texts: Example of invertebrates that are attracted to heat?

texts:
I would like to test a device that outputs heat in order to attract schistosome parasites in water. However, I would like to use a substitute, since I cannot find schistosome parasites for sale.

Are there any organisms that are attracted to heat and are easily accessible?


texts:
I have always been told to watch to see if ant-hole mounds are built up as a sign of imminent rainfall.  My questions are,

if what I have always been told is true, then by what mechanism do ants 'sense' the imminent rainfall?  Is it a case of sensing air pressure drop, increasing humidity or both?


texts:
I am a mathematician and my knowledge about biology is close to zero. I am reading a bioinformatics paper and I would like to understand a bit more about the biology task they are talking about. I cite here the first paragraph of the paper:

  The identification of cell cycle-regulated genes through
  the cyclicity of messenger RNAs in genome-wide studies is a difficult
  task due to the presence of internal and external noise in microarray
  data. Moreover, the analysis is also complicated by the loss of synchrony
  occurring in cell cycle experiments, which often results in additional
  background noise.
  [De Santis, Marianna, et al. "Combining optimization and machine learning techniques for genome-wide prediction of human cell cycle-regulated genes." Bioinformatics (2013): btt671.]

I've searched online for some explanation of this topic and I understand that cell-cycle is a set of events that cells go through for duplicating themselves. I also understand that there are some molecules that are responsible for the regulation of the cell cycle. I know that mRNA is a class of nucleic acid that is responsible for transferring the informations from the DNA inside the nucleus to the ribosomes in order begin the amino acids synthesis. Microarrays are matrices obtained by DNA sequences inside some chip.

What is the cyclicity of mRNA? How is it related to the cell cycle?

I just need a very simple explanation, without any detail, as it is not my field but I am concerned to understand the background.


texts: What feature of rabies pathophysiology causes hydrophobia? Why is hydrophobia unique to this one particular type of viral infection?


texts: Is there any recent evidence for the aquatic ape theory of human evolution?

texts: The aquatic ape theory suggests that many features that distinguish humans from their nearest evolutionary relatives emerged because the ancestors of humans underwent a period when they were adapting to an aquatic or semiaquatic way of life, but returned to terrestrial life before having become fully adapted to the aquatic environment.  Is there any new evidence of this?


texts:
We are interested to farm Scylla serrata which is a type of crab. We introduced the crab weighing 800 g into a environment with 22 ppt salinity with a pH of 8.2. The crab was feeding on around 12 g of chicken meat daily. However at the end of the 4th day, after flipping the crab to its back, it died shortly after. Previously it was able to flip itself back successfully. Note that salinity and pH did not vary much.

What are the possible root causes for death?


texts: Why would low complexity regions be linked with relaxed selection?

texts:
I'm reading a text (Wagner, 2007) on identifying positive selection. In the paper, the author says that low complexity regions are known to be associated with the relaxed selection. I'm trying to understand why this is true. I get that if the region is under relaxed selection then most mutations would be tolerated but why would that lead to low complexity (other than something like slippage during DNA replication)

It's in the section: "Little overlap between variation clusters and low complexity regions"

Wagner A. 2007. Rapid Detection of Positive Selection in Genes and Genomes Through Variation Clusters. Genetics 176(4): 2451–2463.


texts: Which animals live in trees and make noises like rubber ducks at night?

texts:
I was recently at night in a public park in Karlsruhe, Germany. I've heard many (at least 10, probably many more - it's hard to tell) animals in the trees making noises similar to that of a rubber duck which is pressed.

What could that be?


texts: Are there any examples of predators that ambush scavengers?

texts: I'm specifically asking about animals that use a hunting strategy revolving around hanging around cadavers to attack animals attracted to the cadaver, or even leaving part of their catches out to lure scavengers.


texts: cloning and blue white screening in pet21a

texts:
I am using pet21a as a carrier vector for my gene, with R.E BamHI and XhoI,in reverse primer I haven't added any extra nucleotide sequence so that it should code for the histag towards C-terminal. Am I doing so correctly?

Another question: after transformation to DH5alpha, I am getting only white colony(X gal stock was 20mg/ml about 200ul and IPTG 100mM stock about 40ulon surface of plate)... why I am not getting blue colonies?


texts: Reverse transcription with random hexamers -- full length cDNA possible?

texts:
As far as I know there are three common ways for priming when performing reverse transcription on mRNA: 1) polyT-primers, 2) random hexamers and 3) gene-specific primers.
Now, something I am not sure about: Is it possible to generate full length cDNAs using random hexamers? If not, what is the cause? Do you have any literature on this, did not find good information.
I guess with polyT-primers the full length reverse transcription should not be a problem with a polymerase of high processivity and if the transcript is not too long?


texts:
In our school textbook, it is written that sometime forest fires can occur due to rubbing of two horsetails. In the image that I searched online, the plant itself looks thin and rod like with leaflike structures arising from nodes. But many other plants have similar structure. So it might not be its morphology.

What special thing about horsetail starts the fire? Why don't other plants show same thing?


texts: Why does the oxygen produced in the photosynthesis come from water and not carbon dioxide?

texts:
In the photosynthesis equation:

$$\ce{6CO2 + 6H2O ->[sunlight] C6H12O6 + 6O2}$$

The only place where we have 6 molecules of $\ce{O2}$ is in $\ce{6CO2}$. Then it reacts with $\ce{6H2O}$ to form $\ce{C6H12O6}$ and $\ce{6O2}$ that apparently comes from $\ce{CO2}$. So why do we say that the $\ce{O2}$ produced by plants comes from $\ce{H2O}$ and not $\ce{CO2}$? I don't know if I'm the one who's understanding something wrong or is it the photosynthesis formula which is wrong?


texts: Looking for realistic representation of angiosperm sperm cells during pollination

texts:
I've scoured Youtube, google, and a handful of my botany textbooks for a cellular-scale photo, animation, or video illustrating an angiosperm sperm cell during pollination/fertilization.

Unfortunately, other than an unclear glimpse of one in this video I've had essentially no luck.

Ideally, I'd like a microscope recording or a realistically-animated video demonstrating the accurate shape and movement of sperm along the pollen tube and into the ovary.

I think a video will better allow my botany students to visualize this process.

Please let me know if you can find or are aware of any such video or animation from any textbook supplemental materials, journal supplement, or via some reputable online resource.


texts: Why do RNAi pathway proteins exist in the nematode when they can cause them harm?

texts:
When dsRNA is injected in plant, Dicer cuts it and prevents disease.
Why would the plant parasite, M. incognita - a nematode,  die when dsRNA was injected in it? It should have saved it.

Again, to be more clear M. incognita has Argonaute protein and other RISC components for eliciting RNAi. This causes its death.

Then, why does the worm have such factors which cause its death?


texts:
I recently had a conversation with a rather unusual gentleman who was, let's say, more than a little partial to conspiracy theories. He has this idea that governments are lowering "nanowires" from drones, to inject people with chemicals that modify their genetics in order to reduce their lifespan dramatically, or change their opinions and thoughts.

Clearly this man was a fruitcake, and the complexities of his psychology probably warrant a whole separate debate, but he did get me thinking about the theoretical side of how such a thing might be done.

So, as such, I have a few questions on the matter:

Is it even theoretically possible to alter human genetics using only an injected substance? I'd imagine trying to get a single DNA change to propogate through the entire body without being killed off by the immune system would be near impossible.
Since we are aware of genetic markers that are related to predispositions to certain medical conditions (e.g. heart problems, cancers, high blood pressure, strokes, etc), is it possible to modify human DNA to create these issues in a living person?
Has much research gone into how genetics affects thought and opinion, or the way we perceive and react to situations at an emotional level? If so, is it theoretically possible to alter this at a biological level?

I'm certainly not advocating any of this, and I apologise for the unusual nature of the question, but it's something I certainly find interesting to think about!


texts: Why do rabbits often have white hindquarters?

texts:
There are several species of herbivores that have a very visible white hindquarters: several kinds of deer, rabbits, antelopes, etc.

Does the white fur serve a functional purpose, or is it purely random?  Is it defensive enabling them to escape predators, or is it for intraspecies communication?

Examples photos to clarify:

deer

Notice that otherwise relatively well camouflaged animals have visible white fur.


texts: Modern understanding Darwin's "correlation of variation"

texts:
In Variation under Domestication, Darwin makes several references to the concept of "correlation of variation":

  I will here only allude to what may be called correlated variation. Important changes in the embryo or larva will probably entail changes in the mature animal.

And:

  Some instances of correlation are quite whimsical; thus cats with blue eyes are invariably deaf.

In the chapter's ending, he also calls this "correlation of growth":

  Variability is governed by many unknown laws, of which correlated growth is probably the most important.

I gather that this is Darwin's humble way of admitting that there are many unknown unknowns, at least as far as correlation is concerned.

But, since 1859 until present day, what did we find out about this quirky aspect of evolution? Are all cats with blue eyes deaf?


texts:
I'm reading the following paper:

http://jcs.biologists.org/content/123/6/819

The part I am really confused about is when they say:

  Exocytosis appears to use two alternative pathways: clathrin-mediated endocytosis (CME), which is well established by numerous lines of evidence, and the more controversial ‘kiss-and-run’ pathway, which involves direct retrieval of a vesicle at the site of fusion

My question is .. How can exocytosis (contents inside of cell are transported to outside of cell) use clathrin mediated endocytosis?

I thought endocytosis is the opposite of exocytosis, so why do synaptic vesicles use clathrin mediated endocytosis as a method of exocytosis?


texts:
What pathway would E. coli use to make pyruvate from acetate? I have found several papers that refer to a possible mechanism that could move acetate to pyruvate via a three-step process:

Step 1: Acetate Kinase (EC 2.7.2.1)

Step 2: Phosphate acetyltransferase (EC 2.3.1.8)

Step 3: Ferredoxin oxidoreductase (EC 1.2.7.1)

Is this the pathway that would be used in an E. coli system?


texts: Copper for cell incubator to prevent contamination

texts:
For some reason the lab seems to have a problem with contamination every so often.  It's virtually impossible to prevent bacteria, viruses, fungi, etc. from getting into the incubator every time you open the door.  Our incubator is pretty old, we don't have one of the new fancier versions that's made with pure copper inside, which effectively kills microorganisms.

Would it be a good idea to buy a copper plate and place it on the shelf, on which we could put our culture flasks?  Or would it disrupt the flow of heat/CO2 too much?  Would it be better to buy copper foil and wrap the shelves in it, then poke holes into it where all the holes are in the shelf?

We use good cell culturing practices; I don't contamination is happening because people don't know what they're doing.  It just happens over time with enough people working in a cell culture room.  Could copper in the incubator help?  We probably don't have the money to buy a brand new incubator that's made out of copper, so would this be a viable, economic alternative?


texts: Do thymine and uracil ever appear in the same strand of RNA?

texts: Wikipedia says that "in RNA, thymine is replaced with uracil in most cases."  I'm curious what are the cases when this does not happen?  Does this ever occur in normal functioning, or is it an error?  Do T and U ever appear in the same strands of RNA together, or does a single strand just use T or just use U?


texts: Finding the number of chromosomes of an organism

texts:
For a school project I need to find the number of chromosomes of an organism (specifically the adelie penguin, Pygoscelis adeliae). After several internet searches and a look through the encyclopedia at school, I am unable to find a definite answer to this question. Sources on the internet claim anything from 38 to 96 for diploid cells (with none of them citing a trustable study).

Is there any database that records the chromosome number for organisms?

Also, if this information is unavailable, what is the best way to estimate this value? On the Wikipedia article for number of chromosomes for various organisms, it listed the value for some birds, most of them in the 70-80 range. Is it safe then to assume that the number for penguins in general would be somewhere in this range?

Thanks.


texts: Do spring varietes of cereals have a process of vernalization?

texts:
I was wondering about this question - Do spring varieties of cereals have some process of vernalization?
It would be nice to have some description of the main processes' differences of spring and winter varieties.
Thanks!


texts: Are there examples of cells with more than one nucleus?

texts: I've always wondered why cells have only one nucleus, as having multiple would seemingly prevent mutation. Are there examples of organisms with multiple nucleuses? If not, is there a reason?


texts: Is DNase treatment necessary before RNA sequencing?

texts: Is it necessary to treat total RNA with DNase before sequencing it? In particular, if the library prep relies on a poly-A enrichment, is it necessary to remove DNA, knowing that genomic DNA does not have as much polyA as mRNA?


texts: What are these structures in blood from a nosebleed?

texts:
I decided to look at some blood from a nosebleed (not mine) under the microscope and took some pictures of the results. There many large orange structures interspersed within the blood cells and I'm wondering if someone knowledgeable can tell me what they are? Are they skin cells? What are the fibres inside them?

The first two images are x400 and second one is x100.


texts:
I can understand why people are afraid of the doctor, because they have mental concepts of health and medicine.

But why should an animal be any more afraid of the vet than the post office or any other public space?

It doesn't seem like they would understand why they are there or what possible consequences it could have, the same way a human would being in a hospital.


texts: Are there endoscopic technologies for blood vessels?

texts: Endoscopic procedures are used to look inside cavities like intestine, esophagus etc. Is it being used to look inside blood vessels?


texts:
I filmed the creatures below this August in the Mediterranean (specifically, the port of Fornells in Minorca of the Balleares). The images were taken from a boat moored just outside the harbor and floating above a field of posidonia in case that is relevant.

There were many of them and they were whizzing about at high speed:

This is to give you an idea of the scale. The jellyfish on the right was about the size of half a tennis ball.

They were a very strange sight since there were so many of them and moving so fast. You can see a video of them in motion here:

http://www.youtube.com/watch?v=GJCzjXALRJ0

The image quality is not very good but you can see how fast the things were moving. So, any idea what these are? I am assuming they are larvae of something or other but what?


texts:
I have seen recently a documentary starting with introducing of the spectacular black oyster of sweet waters which imitate exactly like a prey fish in order to convey its eggs to predator fish's gills, while it had no eyes to see the form of prey fish favored by the predator fish.

The amazingness of what this creature do provokes me to ask some questions about this strange creature and know more about this odd phenomena and theories represented for evolving of such marvelous creature.

How the black oyster detect completely kind of prey fish which is favourite food of target predator fish ,and make a very detailed simillar image of it in order to deceive the target fish while it has no eyes to see?


texts: Plasma Membrane Proteins and Cytoskeletal Attachment

texts:
Regarding membrane protein functions, which of the following
  statements is CORRECT?

  a. Membrane proteins are responsible for both cell to cell recognition
  and cell anchoring and are stabilised by linking through to the
  microtubulele cytoskeletal ﬁbres.

  b. A protein that is enzymatically active and membrane-bound will
  function significantly differently to a protein that is enzymatically
  active and cytosolic.

  c. Membrane proteins are manufactured in the internal cavity (lumen)
  of the rough ER.

  d. Damage to the smooth ER could alter the makeup of the molecules
  that are displayed at the cell surface.

Regarding membrane proteins, what is incorrect in the statement “Membrane proteins are responsible for both cell to cell recognition and cell anchoring, and are stabilized by linking through to microtubules cytoskeletal fibres"?

I believe this to be wrong due to it normally being Actin Filaments and Intermediate Filaments that attach to Integrin proteins in the cell surface membrane.


texts: How to compare SNP from genotyping results for multiple people with a known phenotype?

texts:
I'm looking at different genotyping profiles available at opensnp.org and am trying to compare profiles for people with different phenotypes.

For example, given 10 profiles of people who can roll their tongue and those who cannot, I am trying to identify what is different between these people and what's similar.

A typical record is in this format:

Rsid, chromosome, Position on chromosome, actual 2 letter mutation

How can such records be compared to identify similarities for a given phenotype? Does RSID uniquely identify a mutation, or is it a combination of rsid and position?

In other words, if one user has rsid 123 at position 555 and another one has rsid 123 at position 666, and the mutation is the same, is this a similarity, or does position matter?


texts: Why does pETDuet-1 only have one T7 terminator but two T7 promoters?

texts:
Why does pETDuet-1 only have one T7 terminator but two T7 promoters (vector map below)? Is there any advantage of having only one terminator? There are going to be two mRNAs transcribed from this vector: one polycistronic (with two genes) and one monocystronic. Also, presumably, there will be more RNA for the gene expressed from the second promoter compared to the gene expressed from the first. That could lead to higher expression of the second protein, provided that the RBSs are the same. Is there experimental evidence confirming/disproving that hypothesis?

Is there any advantage over using polycistronic mRNA vs moncystronic? Have Duet vectors been used for heterologous expression of long (>40kb) biosynthetic pathways?


texts: There doesn't seem to be a lot of information available on research done on warts.  What is the life cycle of a wart?  How does it spread? -- specifically how does it recruit cells to spread it?  What is the life cycle of a PV-infected dermal cell?


texts:
I have collected this plant from the soil in a park in Belgium. I thought it was a child of a plant which was growing nearby but when the leaves started to grow I realised it is a different plant.

When I was collecting it, it was at the stage of having only the seed leaves (still visible in the photo) which are elongated and about 2.5 cm long. In the park, on the ground from where I collected it, these plants were growing in large quantity close to each other. After about 1 week from bringing it home the leaves started to appear. Now about 3 weeks later the leaves are about 2-3 cm long.

Could you help me identify it?

Further clues

First of all, this plant is very abundant in the park but I can also spot it in other places, e.g. close to sidewalks within a walking distance from this park.

This is the plant in the original environment from where I collected it:

I could also find it growing in a pocket of a tree - this suggests to me that the seeds might have fell from a height, so this plant might be a tree (?)

The ground of the park is largely populated by wild garlic. Other than that, some nearby plants are a hornbeam and elderberry.

Here are some further photos of surrounding plants that might be a hint for you:


texts: Do all mammals have a Ventricular system?

texts:
I am familiar with the human Ventricular system that circulates Cerebrospinal fluid. This is needed among other reasons, to suspend the heavy human brain, and for injury protection. Do all mammals have a need a Ventricular system?

Maybe some did not have as strong of an evolutionary need for cerebrospinal fluid?


texts:
I read that Cas9 protein along with guided RNA binds at a specific DNA fragment of foreign organism integrated in a host organism DNA. To make the host immune to virus infection Cas9 along with gRNA which is complementary to viral DNA attaches to it host DNA by unbinding it and then cuts the DNA at this site thereby removing the viral DNA. So the host can only remove the virus that enters second time as it makes a complementary RNA from the first virus that has integrated in it and cannot completely remove virus.

Is the process that I am thinking right?
And can we use Cas9 to cut the DNA at any site of our choice?


texts:
I am looking for a dye that won’t bind to DNA. I want to add dye to proteinase K to make is visible when adding to clear buffer liquid samples. I need it to not bind to the DNA so it will be removed during the purification process. Or a dye that will not show up later under fluorescence during processing.

Thank you!


texts: Is inbreeding really efficient at producing homozygosity?

texts:
Inbreeding results in homozygosity.

I've come across this concept many times  and there's a question that comes to my mind every time I read it.

Let us suppose the character we are trying to establish is dominant trait controlled by a biallelic gene and the two individuals (animals) we have selected to inbreed  both have the genotypes Aa.

Aa x Aa = AA/ Aa/ aa in the ratio 1:2:1

So the possibility of having a homozygous dominant is 25% while that of heterozygous is 50%.
As the breeder has no access to technologies and find out the genotype of the F1 individuals there's a possibility that he would choose two F1 individuals with Aa genotype once again (which has the highest possibility of occurrence). And the same is repeated , production of F2 offsprings with 50% possibility of heterozygous individuals.

Edit:

So getting a homozygous dominant individual is very less likely to happen.

My question, is inbreeding really efficient at producing homozygosity?


texts: How is hibernation/aestivation different from anesthesia?

texts:
How do hibernation/aestivation happen?

I read on wikipedia that a squirrel injected with the body fluids of a hibernating fellow is more prone to hibernation. If hibernation/aestivation are driven by biochemicals and not merely the weather, can the process be induced in higher beings such as humans to replace surgical (etc) anesthesia? How is the one different from the other?

p.s. Or perhaps to induce hibernation for the trip across the Solar System (+:


texts: Where does mycelium growing in wood get oxygen?

texts:
As per title, where does mycelium, growing in wood, get its oxygen? I mean when the mycelium is spreading into wood, say an old log, beneath the surface.

As an example, say I put mushroom dowels into a log, and seal it over with wax - standard way of doing it. Where is the sealed off mycelium getting it's oxygen ?


texts: Can the human brain be reduced to a binary system?

texts: Does the brain really function like a computer as in, ultimately every response is related to a binary sequence based on whether particular neurons fire or not?


texts: How do I offer a generous gift to sweet-seeking wasps, bees, hornets, bumble-bees?

texts:
I was having ice coffee and melon ice and after visiting the lavatory I saw that a wasp was having a good time with my already finished ice coffee.

Trying to begin the melon ice the wasp kindly insisted to take a first bite despite my insistence to not do that.
Feeling generous, I offered the wasp the already accepted ice coffee, but despite my best efforts (Waving it in the correct direction so that it get the smell directly before its nose) it only flew uselessly in circles.

Is there any method to give those sweet-seekers a meal which they gratiously accept (and in effect save us the nuisance to shoo them away) ?


texts: What biological functions does crying serve?

texts:
Tears suddenly start flowing out of our eyes when we find our long lost friend or when someone unexpectedly decides to break up with us. Do tears really save us from harm? Or are they just the reflex shown?

What biological purpose do tears serve for the body?

As I understand it, crying causes endorphin release, specifically leucine-enkephalin. This serves as a painkiller for us. Are tears the only way to accomplish this? It seems I am missing something because oozing out of our eyes is an inferior pain distribution system to say; the circulatory system.


texts: What are sources for learning bioinformatics for self-learning?

texts: What are the sources for learning bioinformatics(books, websites/MOOCs)? Does it require prior knowledge of programming language because I am a complete noob when it comes to programming language.


texts: Dehydration Synthesis: Why does a monomer contribute a -H instead of an H atom?

texts:
My Campbell's Biology 9th edition textbook says that a dehydration synthesis is a reaction in which water is produced while two monomers are joined together. Specifically, it makes the following statement:

  One monomer provides a hydroxyl group (-OH), while the other provides a hydrogen (-H).

Sorry if this is a silly question to ask, but what I'm wondering is how exactly a Hydrogen electron joined with a Hydroxyl will create H2O? Why isn't it a Hydrogen atom (1 proton and 1 electron) rather than just the electron which moves?


texts:
I've been reading up on the Fukushima nuclear meltdown and its effects it had on the environment. The iodine-131 initially released from the incident decayed after 8 days, but other isotopes such as cesium-137 and strontium-90 have a half-life of 28.7 and 30.2 years (about 300 years to completely decay).

Apparently, large quanties of cesium-137 were found in neighbouring countries as well as in seafood near Japan.

Now, for something like nuclear isotopes, not having the required knowledge can lead someone to fear something that might be harmless (or confirm some doubts about the issue), hence why I am here.

From my research on scientific websites and different governmental regulations, I found out that food and water in Japan have a legal limit as to how much cesium-137 a food item can contain. Especially since cesium-137 ressembles potassium and therefore being easily taken up by the body, this is worrying.

To my understanding, the way a radioactive isotope creates havoc in the body of an individual is that:

It ressembles a normal element we usually consume, like iodine, potassium for cesium-137 and calcium for strontium-90.
The body digests it and it is stored in the body.
It emits radation for a certain period of time, anywhere from 8 days for Iodine-131 to years for cesium-137.
The prolonged radioactivity from these isotopes causes cancerous cells to occur.
A tumour or other form of cancer develops.

If this is what happens for isotopes like cesium-137, how can it be possible to eat food or drink water containing ANY cesium whatsoever? Sure, the radiation isn't so bad, but what is important to take into consideration is that this is internal and highly centralized radiation. This is a completely different thing to external radiation.

For my questions about the topic, I would like to know three things (which could really put many doubts to rest).

QUESTIONS

The first is, is my understanding described above correct?

The second is, how does this affect us healthwise? We are stuck with these debris of cesium-137 and strontium-90 for the next 30 or more years, but what effect do they have on us?

If someone ingests an atom (or a small amount) of cesium-137, what affect will this have on this person's body?

Finally, for someone living in North America, how much of these debris are there, either that got here from the wind, products, food, water, etc.?

EDIT: If someone knowledgeable on the subject could answer the questions directly (highlighted by means of italics), it would be very much appreciated.


texts: Are there any studies detailing the overall "-omics" effects of using bleach to synchronise a C. elegans population?

texts: I wasn’t able to find papers detailing the changes in the transcriptome/proteome of C. elegans when synchronised by bleaching vs not-bleaching. Hopefully someone can point me in the right direction!


texts: introduction of system biology to bench biologists

texts: I am trained as a bench biologist and I want to learn about system biology and introduce a system biology type of analysis into my study. Can somebody recommend books and websites about system biology for biologists?


texts: Determining the appropriate bioconjugate

texts:
I'm thinking of crosslinking two proteins. The crystallographic nature of the interaction and the binding motif for each molecule is know. The paper says the intermolecular contacts (over 50; van der Waals radius 5 angstrom) are made between the motifs in these two proteins. I also know that one of the motifs on one protein has a sulfhyryl (Methionine) and for the other motif on the other molecule I (think) can use a primary amide reactive moieties. Now this is where my question is.

Would I be correct in thinking that the best cross linker to use is a heterobifunctional cross linker, with a spacer of 10 (or 5?) angstrom in order to pick this interaction up specifically and stabilise it?

I desperately need a guidance on this. I have used the life technologies crosslinker selection tool and the crosslinking technologies hand book but I can't quite figure out based on the information I have, what cross linker length I need to use. I'm not worried about the cleavability, solubility and membrane permeability parameters.

UPDATE:

I know that the binding motif on the first protein it has Tyrosine, Proline and Methionine.

Looking at the groove contacts, the second protein is interacting with this motif, using Tyrosine and Glutamine BUT the second protein also has Tryptophan, Lysine, Glutamic acid and Methionine.

UPDATE 2:

I found specially close Glutamic acid (E) and leucine (L) on my first protein, specially close to Lysine (L) on my second protein although its not in the consensus sequence for the second protein. They are less than 10 angstrom apart. is that any better? So presumably I can use the homobifunctional linker?

Many thanks in advance


texts: Are all animal species prone to cannibalism induced prion infection?

texts:
Humans have the tendency to get certain prion diseases when eating human flesh. It's known animals can get prion diseases as well.

Does cannibalism among other animal species also make them more susceptible to get a prion disease, and are there distinctions between mammals doing so and other orders like reptiles, birds, fish etc.?


texts: How do our red blood cells (RBCs) get oxygen? Do they even need it? They have no nucleus and no organelles, so I think they don't need it.


texts:
Why is it beneficial for trees to grow that tall?

This sounds like a kid's question Mom, Dad... why are trees so tall?

Costs and Benefits

There are some obvious costs:

Need much Carbon and other nutrients
maintenance cost
energy cost (for growing, to bring water (and nutrients) up to the higher leaves, etc...)
Sensitivity to wind
etc...

Potential benefits I can think of:

Competition for sunlight
Better dispersal
protection against predation
Some birds (maybe especially those that are potentially good seed dispersers) prefer to land on high trees (avoiding the cost of regaining altitude). Being high attract these birds which eat the fruits and disperse the seeds.

Are there other potential benefits?

Specific to palm trees

I am currently in Bali, Indonesia looking at palm trees that seem to have a very low competition for sun light (the forest is not dense, the light is intense), there are no tall predators (but being tall might be a protection against climbing predators as well and there are indeed monkeys and other potential climbing predators) and looking at coconuts, papaya and banana I can hardly think that being tall helps to disperse further away (seeds dispersal by barochory). So, why (evolutionary reasons) are palm trees so high?


texts: why do overweight individuals sweat more than ordinary people?

texts: A common phenomenon that I have noticed while traveling in buses is that overweight individuals seem to sweat a lot more than people with ordinary weight. Is this a coincidence or is there some science behind this?


texts: How does the colinearity of the HOX genes determine the body plan of an organism?

texts:
I was recently reading about colinearity in the HOX genes that give an organism its high-level body plan (where the order of the HOX genes on the chromosome follow the head-to-tail order of body segments, such that the head gene comes before the thorax gene, comes before the abdomen gene, etc).

I'm really just a layman  interested in this stuff (only completed A & P I), but I was under the impression that the location of genes on a chromosome has no bearing on the expression of those genes or phenotype of the organism -- in other words, that genes can be anywhere on any chromosome.

Do we understand how the order of the HOX genes ends up being expressed as the order of the body segments? Do we know why the positioning of these genes matters when the order of other genes don't?


texts:
I found this guy in my backyard. I have no clue what he is, though I'm assuming it's a jumping spider after doing a little bit of searching.
For context, I live in Southern California, close to being right in between LA and San Diego. It's suburban, though there are a few reserves that are close by. It is incredibly small, probably no bigger than a dime. It's mostly orange and black with some rings of white on the legs. It's pretty hairy as well.
The only thing I'd like to know is if it's poisonous or dangerous, as I don't need my dogs getting sick or injured. If possible, I would also like some links for some background reading on it!


texts:
I regularly encounter students who believe humans came from amoebas and when asked why they often say Macro-Evolution has been scientifically proven.

Macro-evolution is defined as evolution at or above the species level, which leads to the problem: Scientific evidence does exist for speciation at the Biological Species Concept (BSC) level, but not for all species concepts and only if a helpful definition is employed. Lions and tigers are considered different species and have been know to reproduce--sometimes with fertile offspring. Therefore, what benefits are there to such a broad category as macro-evolution?

The distinction between lions and tigers is so much smaller than feathered vs. scaled creatures! Surely the current definition of macro-evolution is overly broad and confusing to newcomers. Only the fuzzy edge of the macro-evolution definition has been proven. Proving that 1 inch of a yardstick exists does not prove that the rest does. There is a distinct lack of rigor to the statement that "macro-evolution has been scientifically proven."

Surely the definition of macro-evolution could be chopped in half with the goal of distinguishing between relatively trivial changes (Lion vs. Tiger, but beyond micro-evolution) and relatively non-trivial distinctions (either at and above the genus or the family level). The "trivial" changes could be termed "Middle Evolution" and work something like this:

1.) Middle evolution: evolution at or above the species level, but below the family level.

2.) Macro evolution: evolution at or above the family level.

Substitute the word genus for family in the above definitions if that seems better. I admit that line would be somewhat arbitrary, but would not the term "Middle Evolution" be informative?


texts: Can cerebrospinal fluid pass through the pia mater or ependymal cells of the ventricles?

texts:
During a lecture, a professor commented that the cerebrospinal fluid and interstitial fluid of the brain parenchyma have similar composition because they can exchange with one another. This struck me as surprising because I was always under the following impressions:

pia mater is essentially impermeable to fluid (therefore CSF from the subarachnoid space could not penetrate it to be in a passive exchange with the underlying brain tissue)
the ependymal cells of the ventricles (besides the choroid plexus where blood is 'pushed' through) is impermeable to fluid...i.e. CSF cannot leave the ventricles to be in passive exchange with the surrounding brain tissue.

Could someone please confirm if these two impressions are correct, and, further, if they are correct, could someone confirm the accuracy of the professor's claim and by what means it is true?


texts: Does avoiding medication that alleviates symptoms shorten the length of a cold?

texts:
People use over the counter (OTC) medications to relieve symptoms of the common cold.

However, these symptoms are part of the immune response, right? They are driven by the body responding to the virus and attempting to make the body less habitable and thus easier to kill it off.

Do OTC medications that reduce cold symptoms cause the cold to persist longer? Should such medications be avoided if the goal is to reduce cold duration rather than symptoms?


texts: Why is the number of PCR cycles limited?

texts:
I've been told that the maximum number of cycles in PCR is between 20 and 30.

Is this true, and what are the reasons for this limitation?


texts: Monohybrid Recombinant Frequency? (three point Gene Linkage)

texts:
I am curious to know if it is completely impossible calculate recombinant frequency for monohybrids ( three point link, gene map etc.)

Here is an example:

Marker 1

xx= 25
xy=100
yy= 20

Marker 2

xx=30
yx= 89
yy= 20

Marker 3

xx= 100
yx=50
yy= 100

This is what I think it would be like for x:x Marker 1 to 3

grand total = 534

So from Marker 1 to Marker 2 it would be 25+30/534 = 0.1029

Marker 2 to Marker 3 : 30 +100/534= 0.2429

Marker 1 to Marker 3: 125/534= 0.2340

Am I on the right track --- if not can you please show how it would be done for this example?


texts: Why did humans evolved the scratch reflex?

texts:
I've been wondering about this for some time, and I can't come to an answer...

Everybody keeps telling me that scratching one's own skin is bad. It damages the epidermis, creates the hazard of malicious bacteria getting past the skin barrier, and creates the vicious circle of scratching increasing the itching, and itching increasing the scratching (I think I recall reading that this vicious circle also happens even without any special skin diseases, like atopic dermatitis - I might be mistaken here, however)

So, it seems there are hardly any benefits for the body from the scratch reflex. However, if this was true, then "grandma Evolution" wouldn't have given this to us!

What are the benefits of scratching? Are there any benefits of it from the evolutionary point of view? I can come up with just one such benefit, namely fending off insects such as ticks, mosquitoes, fleas or lice. Would this be the evolutionary benefit of scratching?


texts: What species is this bushy thorny yellow-flowered angiosperm from Morocco? Photographed in spring in a dried up river bed. The bush is about 1 metre high.


texts: Why does sympathetic activity constrict pulmonary vessels?

texts:
I don't know understand why sympathetic stimulation constricts pulmonary vessels?
I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need more oxygen supply. Doesn't constriction of pulmonary vessels reduce the gas exchange?


texts: Can "red" cone cells actually see much red light?

texts:
In electronics, the most common color scheme is the "red-green-blue" (RGB) scheme.  This choice is often justified by claiming that the long-  (L), medium-  (M), and short- (S) type cones in the human eye are most sensitive to red, green, and blue light respectively.  But this seems clearly wrong if you look at the actual normalized frequency receptivity spectra for the three types of cone cells:

It's clear that the L-type cones are actually most sensitive to yellow-green light and are actually relatively insensitive to red light. (Presumably the brain distinguishes between yellow, orange, and red light by the rapidly decreasing ratios of M-type to L-type signal.)

My question is threefold:
(1) The L-type cones are usually called "red" cones.  Is this simply incorrect, or is there some justification for this name that I can't see from the receptivity spectra?
(2) Does the RGB color scheme give a better color range than, say, a "yellow-green-blue" scheme (which would more closely correspond to the actual cone sensitivities) simply because red is at one end of the visible spectrum, so you can more easily get a wide color range?
(3) If this is the case, do we not use a "red-green-violet" color scheme (which would give an even wider color range) simply because the human eye is so much more sensitive to blue than to violet light?


texts:
The "big five" assumptions are the ones listed in the main text. However, the basic formulation of Hardy-Weinberg equilibrium also relies on a few other assumptions;

Allele and genotype frequencies don't differ between males and females. That is, the basic form of Hardy-Weinberg does not cover sex-linked genes.

so, is there a modified formula?


texts: Why lab technicians use indirect (antibody reaction) method for diagnosing?

texts:
In microbiology we have two types of microbial diagnosis. The direct method is where we detect the invader's DNA, Antigens or culture to see the exact pathogen while the second, indirect, method is the reacting the antibodies of patient's serum with different reagents.

If we use the indirect method (antibody reaction) and find that they are producing antibodies against a specific disease (let's say streptococcus A) what is the benefit of having found that they are fighting Strep A since the body is already clearly fighting it and putting up the best defence to fight the disease?

Would a doctor really prescribe antibiotics even though here is already an immune reaction against the infection?

If diagnosis and treatment are useless then why do we waste the time to do it?


texts: Gene products of recessive/mutated alleles

texts: I probably would not cite a specific example, but some recessive allele work by encoding for the non-functional form of an enzyme. While the dominant allele encodes for sufficient levels of functional enzyme that the dominant phenotype is present in heterozygous individuals. Will the individual have many uselessly non-functional proteins floating around along with everything else?


texts:
How does exposure of fish to microplastic particles decrease egg-hatching and give young fish a craving for them?

From Garbage in, garbage out: marine plastic 2016-06-24 | Espresso

  There is more than just ocean beautification at stake; many creatures
  ingest plastic, and a recent study showed that exposing fish to
  microplastic particles not only decreases egg-hatching but also gives
  young fish a craving for the stuff.


texts: What determines which symptoms an allergen will cause?

texts:
Allergies result in many different symptoms such as sneezing, runny nose, itchy eyes, coughing, rashes, swelling of the face, stomach pain, vomiting, dry skin, anaphylaxis, etc.

An allergen can cause different symptoms for different people who are allergic to it... and different allergens can cause completely different symptoms for the same person. What characteristics of an allergen and/or the person determine what symptoms will arise?


texts: Why is cognitive maturity related to organism lifespan in larger animals and mammals?

texts:
I am not a student of biology, so I should provide some context to me asking this rudimentary question. While doing a graduate-level course on Reinforcement Learning, the instructors focused on how we as mammals have such amazing intellectual potential and how we tend to learn by examples of outcome based on our actions. This set me thinking about the high disparity between different species of multicellular organisms in how we mature.
I would state a couple of examples to back my point, I am unsure if this list is conclusive or not.

Elephants(Average Lifespan: 60-70 years): Elephant babies tend to stick to their families until they generally mature.

Humans(Average Lifespan: 70-80 years): Human babies are generally dependent on their parents for at least 8-12 years before they start demonstrating some intellectual maturity, which is a good 10-15 percent of their average lifespan)

Birds(Average lifespan is species-dependent, but assuming a 10-year span): Bird offsprings are extremely fast learners and tend to veer off independently within months of their birth.

Fishes (Medium to short lifespan): Not an extremely well-publicized parenting method for their offspring. Fishes learn to swim and hunt for food at extremely young ages, which is a sign of cognitive maturity.

Insects (Short Lifespan): Generally parenting is related to feeding offsprings for a short while before they become entirely independent.

As can be observed, the general span for the attainment of cognitive maturity in such organisms seems to be an inverse function of the average lifespan of the parent, and I wonder, what could be the reason for it?

I absolutely apologize for any inaccuracies I might have cited because what I state is purely from a layman's observational perspective. I would be delighted to know what the bright folks here have to say on this matter.


texts: Can all biological processes be understood as computations and studied as such?

texts:
Can we understand a cell as an organic computational device? In that case the whole organism can be considered an ensemble of a large number of interacting computational devices?

If this is the case, biology can be studied using methods of graph theory, network theory, computation theory and complex systems theory.


texts: Best method for measuring very young plant growth?

texts: Is there a preferable method for measuring plant growth for a plant before the "sprout" stage? Preferably at the microgreen stage? I assume it would not involve some type of leaf based measurument, since they would have few, and maybe then should be based on mass or volume somehow?


texts:
Suppose you swallowed a little capsule with a blunt poker which had
some impulse of force applied every few seconds.  What would be the
sensitivity ordering (of lips, mouth, throat, esophagus, stomach,
duodenum, jejunum, ilium, colon, rectum, anus)?

Does sensitivity just fall to a minimum in the middle of the digestive
tract and increase again to the exit, or are there any other extremum
(e.g., at the ilium-colon interface) along the way?  I'm guessing
people could infer the answer by looking at the density of nerve cells
along this route, but I couldn't find any comparable scientific data
in my quick internet searches.


texts: Can Tajima's D and other population genetic tools be used to copare Arabidopsis ecotypes?

texts:
I am currently investigating 2 genes in Arabidopsis taliana that are a product of a recent duplication even (observable from synteny and phylogenetic analysis). In addition to the molecular and biochemical functions of these genes, I was wondering how evolution is acting on them at the population level. There the genome sequence of 1300 ecotypes of Arabidopsis from all around the globe available. So, I was wondering if I could use all these sequences to quantify nucleotide diversity and/or Tajima´s D? However, I am not sure if this is conceptually right, since I am not using an actual population, but I am just aligning 1300 sequences as "global population". what do you think?  is this a good approach to see the level of variation for each gene "globally"? is this "global" view scientifically and statistically relevant?

Regards


texts:
The underlying intuition of Hamilton's model of inclusive fitness is that we should study social behaviors from the point of view of actors -- rather than the recipients. To build his model, Hamilton expresses the genotype of the actor $j$ in terms of the genotype of the recipient of
the behavior, $i$. The genotype of $j$ is decomposed in two parts,
``genes which are copies by direct replication of genes in $i$; the
other part consists of non-replica genes'' (Hamilton 1970, p. 1219).
Hamilton (1970) further defines $q_{i}$ as the gene frequency of the
replica part, $b_{ij}$ represents the replica fraction, and $q$ is the average gene frequency in the population. From these definitions Hamilton (1970) jumps to the equality:
\begin{equation}
      E (q_{j}) = \frac{1}{1-b_{i}}\left\{ (b_{ij} - b_{i})q_{i} + (1-b_{ij})q\right\}
\end{equation}
where
\begin{align*}
  b_{i} = \frac{1}{n}\sum_{j}b_{ij}
\end{align*}

How did Hamilton derive the above equation?

Here is what I think Hamilton is doing. My impression is that the above equation expresses $E(q_j | q_i)$ as a linear regression on $q_i$. In other words, I think the above equation is equivalent to:

$E(q_j | q_i) = E(q_j) + \beta (q_i - E(q_i))$

$E(q_j | q_i) = q + \beta (q_i - q)$

In fact, this equation is equivalent to Hamilton's equation if the regression coefficient is:

$\beta = (b_{ij} - b_i) / (1 - b_i)$

However, I haven't been able to derive this regression coefficient. Given that $\beta = Cov (q_j, q_i)/Var (q_i)$, I suspect that the way to go is to rewrite $q_j$ and $q_i$ in terms of $b_{ij}$ and $b_i$ and calculate the regression coefficient.

Reference:

Hamilton 1970 "Selfish and Spiteful Behaviour in an Evolutionary Model"
http://www.nature.com/nature/journal/v228/n5277/abs/2281218a0.html


texts: Are there any organisms that lack ATP synthase?

texts:
ATP synthase is used by cells to synthesise ATP from ADP using energy from a proton gradient. Depending on which sites I look at, this is either a universal feature of living cells, or it's "almost universal", used by the vast majority of organisms.

As Superbeast points out in a comment, ATP can also be synthesised on the substrate level via the Krebs cycle. However, I would like to know if there are any organisms that only synthesise ATP this way. In other words, are there any known organisms that entirely lack the ability to produce ATP synthase, and produce ATP entirely through the Krebs cycle, or through some other mechanism not related to ATP synthase?

If there are, I would like some information about them. Are there many such species or just a few? Are they all prokaryotes or all eucaryotes, or some of each? What kind of environments do they live in?


texts: Chart of blood pH across different animal species?

texts:
How does blood pH vary across species?  I can't find an article or chart listing this kind of information.

So far I've found bits and pieces like:

Human blood pH is nominally 7.4.
7.4 seems to be a good value for dogs and cats (¿and probably all mammals?).
For racehorses it seems to be roughly 7.4.
Silkworm, Bombyx Mori, blood (hemolymph) has a pH of 6.45 (larval) and 6.57 (pupal).
Bullfrog muscle(!) pH runs roughly 7 to 7.3.  (Link to The Journal of Experimental Biology article, PDF) It's not clear if this is also blood pH.

But no real comparison.

Is there an authoritative comparison of blood pH between: mammals, reptiles, fish, invertebrates, etc.?

Is nominal/average pH at least constant across all mammals, or across all reptiles, etc.?


texts: Variation of length of circadian rhythm in humans in absense of time reference

texts:
Are there any studies which show the range of the length of circadian rhythms for people that are removed from actual time, (Eg no sunset/ sunrise, no clocks or other reference of time)?

For example, what proportion of people tend to have a natural 30 hour rhythm or greater?

I ask because I would like to know if it is a possible cause of insomnia, how likely insomnia is caused by this, and if this knowledge might in some way lead to solutions for insomnia


texts: Where are epitopes located on HLA molecules?

texts:
Normally HLA molecules present cellular and extra cellular proteins to the immune system; presumably the proteins in this case are where antibody /t-cells etc bind.

But when an organ is transplanted to a HLA incompatible recipient, are they binding to the HLA molecule itself? If antibody response was reliant on the proteome expressed in and around the cell HLA incompatibility wouldn't be such a problem.

What about auto immune diseases?


texts: A human brain can generate electrical signal. So it generates magnetic field as well. Is it possible to affect a brain with electromagnetic waves?


texts: Do smaller intelligent animals have a higher neuron density to account for their seeming intelligence? Otherwise, what?

texts:
It seems like there's a lot of very small animals that have a much higher intelligence than what you would expect if you linearly projected intelligence as a function of brain size. There's ravens, crows and parrots which are much smaller than humans but have a recognizably high intelligence and emotional capacity. Then there's rats and general rodents like squirrels or similar animals like raccoons, and I guess an octopus to throw in which are good at problem solving and fierce fighters. Then there's also bugs like ants which are somehow very versatile and can adapt to many situations despite being that tiny, and with recent information may also have a recognizable emotional capacity like possibly bees.

It would make sense to me if the correlation between neuron density and intelligence isn't linear, but I don't have the information to make any determinations.


texts: Does difference in expected life duration between men and women have biological nature?

texts:
It is known that men in most countries live less than women. I wonder whether it is due to different life conditions or because male and female organisms differ?

For example, I heard that testosterone may cause cardiovascular deceases. Is it true? Are there other biological mechanisms that can shorten men's lifespan?


texts: What is the main difference between "Terminalia ivorensis" and "Bucida buceras"?

texts: Google images yields photos of similar trees, but they have separate Wikipedia article. I want to know the major difference allowing to identify which is "Terminalia ivorensis" and "Bucida buceras".


texts: How much energy can one muscle contraction deliver?

texts:
How much energy is available in a single muscle contraction?  I'm guessing the correct units are J/kg, but I'm open to more correct units.  I'm looking for work done, not total energy dissipated (not interested in heat)

The goal of such a number is to figure out an upper bound on how much work a human body can do if it is never permitted to reset a muscle by moving the limb in the opposite direction (If the bicep does work for this test, the triceps isn't permitted to contract to return the curled arm back to its initial straight position)


texts:
I have been reading about next-generation sequencing technologies that can sequence long reads. Even though the origin of my question is sequencing technologies, the question I am asking is about the basics of DNA biochemistry.

One of the issues in manipulating DNA samples seems to be the ability to circularize long linear DNA molecules into circular DNA molecules. What are the technical challenges of circularising DNA molecules longer than 50Kbp?


texts: Can Anyone Tell Me , Which Insect or I think Moth Is This

texts: Region : Asia ( India ) , Size is about : 4 cm . Since yesterday this Insect is in the same place . I don't know any other info , I was just curious to know about this Insect.


texts: What are the marker enzymes for Nucleus, Ribosomes and cell membrane?

texts:
Are there any marker enzymes present for ribosomes, nucleus and cell membrane. For mitochondria there are many, for lysosome it's cathepsin. I read about the marker enzymes of most of the other cellular components, but no information is there on these three.
If no marker enzymes are present then how are ribosomes, nucleus and cell membrane are identified.

I am specifically looking for marker enzymes which can help identify the pellet component after subcellular fractionation.


texts:
Toxoids produced by tetanus and diphtheria bacteria are detoxified
  with formaldehyde, yet their antigen properties remain.

Source : Biological Science by Taylor

What does formaldehyde do ?


texts:
This is not purely biological question but how do the companies making DNA analysis know what your DNA means? Is there some database describing human DNA?

I watched some documents about DNA, gene editing... and people in the documents were often working with some infographical like documents which described some chromosome or desease (I don't know what exactly that was, I am an amateur trying to make sense of it) but I was not able to find anything as they had on the internet.


texts: 1% water solution of deoxycholic acid. How is it prepared?

texts:
According to Sigma, the solubility of deoxycholic acid is:

0.24 g/L in water at 15C

According to the FDA, Kybella (trademark) is a 1% water solution of deoxycholic acid.
How did they do this?


texts: Why sister chromatids and daughter cells but not brother chromatids and son cells?

texts: In biology, why do we have terminologies in terms of female relatoinships such as daughter cells and sister chromatids and not in terms of male relationships. When did this custom started and is there a reason for it ?


texts: Although the speed may vary a lot based on factors like protein size/scale of conformational change/type of changes (small block change/arm movement,etc), are there examples of experimental results of time scale of such processes? (Only a single conformational change is considered i.e. the time delay between the begain and the end of a single conformational change event of a single protein (or subunit to be more precise?) )


texts:
Found this "egg ball" on a gate near a greenbelt north of Seattle, WA. From other posts here, it looks similar to snail eggs, but they do not have the webbing. Two days later I went back out to measure it, but it was gone. Maybe hatched or eaten?

s://i.stack.imgur.com/tj6gT.jpg


texts: I am interested in scaled price on 1 stem cell, only for educational purposes. I couldn't find any information about pure price on stem cell, only whole procedure price. So if anyone know, I'll be very appreciated.


texts: Why is a cellular structure necessary to satisfy the definition of alive?

texts:
I was looking at this image and reading through the Wikipedia page for viruses and it says that to satisfy the definition of "being alive" the organism must have a cellular structure, but it seems to me that if an organism has all these other factors without a cellular structure, it is still seemingly alive, no?

So why exactly does an organism need a cellular structure to be alive? What is the rationale for that criteria?


texts:
Plateletpheresis is seperation of platelets from whole blood and putting the leukocytes and erythrocytes back into the blood.

If the person donating platelets does not have hemophilia than could a hemophilia patient get a periodic transfusion of platelets from a non-hemophiliac platelet donor so that his hemophilia is less severe whether it is hemophilia A or hemophilia B?


texts: Can fruit tissue be cultured and grown independent from the plant?

texts: Can fruit tissue be grown in a tissue culture as is done to other plant tissues? From the answer to this question, I learned that fruit is alive. Could it be possible to manufacture fruit products without plants, using this method?


texts: Is there any evolutionary/physiological advantage to multi-lateral symmetry?

texts:
Just wondering ; I get the impression a large number of multicellular organisms are multi-lateral in their physical structure. Why would evolution/mutation have retained multi-lateral symmetry in an organism? What advantage/s does symmetry provide an organism?

EDIT:
By multi-lateral symmetry I mean at-least bi-lateral symmetry (as in the case of many beings such as elephants, crabs and fishes), but perhaps more than bi-lateral too (starfish come to mind)

END EDIT:


texts:
What triggers the opening of sodium channels in a neuronal membrane? Is it acetylcholine that activates sodium channels in the postsynaptic membrane?

Are sodium channels like receptors that have to bind to something (like a protein or an ion) to open? If so, what is the substance that forces Na+ channels to open?


texts:
Ok, so I know whats the difference between the three terms in botany. Autogamy is pollination within the same flower, Geitonogamy is pollination from the anther of one flower to the stigma of another flower within the same plant and Xenogamy is the pollination from the anther of one flower to the stigma of another flower of another plant
But my question is what if there occurs pollination from the anther of one flower to the stigma of another flower of another species. Does it still count as Xenogamy?
My research turned out slightly problematic as I see different different definitions here's one from the google dictionary

fertilization of a flower by pollen from a flower on a genetically different plant.

But the problem is Wikipedia shows another one (well don't @ me if these sources sound unconventional, do enlighten me if there's an established organisation for defining these terminologies)

Xenogamy is the transfer of pollen grains from the anther to the stigma of a different plant. This is the only type of cross-pollination which during pollination brings genetically different types of pollen grains to the stigma. The term xenogamy was first suggested by Kerner in 1876

So according to wiki, my case is xenogamy but according to google definitions it isn't (as there's no fertilisation) Whats the general consensus?


texts: When the sinuses flare up, it can get very painful.  Thus, my question - what biological mechanisms cause the congestion and especially the pain associated with sinusitis?


texts: Where to find gene manipulation video (or photos)

texts:
I hope Im not asking a dumb question!

Where can i find video of gene manipulation in action under microscope?
Like extracting a gene from a cell, fixing gene mutations, putting the gene in a vector, that kinda stuff. Is this too small to show in video or photos?

If i look up youtube all I find is scientists using lab machines and equipments except for under miscroscope!!!


texts: Why biologic systems tends to become more complex?

texts:
From elements, chemical compounds, cells, multicellular organisms, society evolves and with each step possibilities increase and things get complex. We are builing structures like ribosome builds polypeptide chains.

So my question is why humans keeps continue to live, does our brain is unconsciously tries to get our society to get bigger, why life has a tendency to get complex with time?


texts: How do naked mole rats suckle when their lips are behind their teeth?

texts: Lips are believed to be needed in mammals so that we can create an ample seal for suckling milk, and while I'm aware they /do/ have lips and can create a seal, they are behind the teeth. How do they accomplish suckling without those teeth getting in the way? Can they move them independently like fanged deer, do the newborns lack teeth all together? I feel like I'm missing something.


texts:
I am from Philippines and I found this in my room.
This arthropod has 6 legs and have a bit long Chelicerae like spiders that can fold to hold its food. It's about half an inch long. It also looks like a
scorpion but I could not find anything like it on the internet. Thank you!
I've also noticed that it can jump and it also produced spider silk.


texts: Does a tubular sodium reabsorption cause a stimulation of β2-adrenergic receptors?

texts:
I read the study "The Role of Aldosterone in Obesity-Related Hypertension" and there is one thing I didn't understand. They write: "According to norepinephrine-induced tubular sodium reabsorption, stimulation of β2-adrenergic receptors leads to activation of the Na–Cl cotransporter through suppression of the serine-threonine protein kinase WNK4 in the distal tubule." Is According to meant like due to? So does a tubular sodium Reabsorption cause a Stimulation of β2-adrenergic receptors?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4886496/


texts:
Do female chest size have anything to do with muscle?

I know many female athlete and their average breast size is much bigger than normal female that does not tend to play sports. Do this have any relation to chest muscle?? If so can you explain how it does.

Thanks in advance


texts:
I can't seem to find the answer to this. Not even Wikipedia could help- it mentioned bacteria and fungi that have cellulases but not plants. Using my own reasoning, I would think that

On the one hand it is better if plant cells do not have cellulases so that they do not break down the cell wall. Although maybe it doesn't matter because the cellulases would not reach the cell wall without being actively transported out of the plasma membrane.
Perhaps it might be useful for plants to have cellulase. I don't know if plants have any sort of immune system like humans, but plants also get bacterial and parasitic infections in their cells. Maybe plants should have some mechanism to destroy an unhealthy cell? In that case, the destroying cells would need to use cellulase, would they not?


texts: Real embryo pictures: How different zones(speeman organizer, marginal zones...) are known?

texts: In many textbook, figures of embryo are drawn,but in reality how biologist know which zone is this one of  an embryo in gastrulation stade? Except the dorsal lip here i can't localize other thing.


texts: Is there a term for tool use in animals?

texts:
Is there a technical/scientific term that scientists use to refer to tool making abilities found in certain types of animals?

Reference http://en.wikipedia.org/wiki/Animal_cognition#Tool_and_weapon_use


texts:
I am trying to find the name of this plant for a while. The closest I got is Yucca filamentosa color. The leaf blades are near 4-5 inches and are almost thin(without pulp). Please help me in identifying it.

Location: Hyderabad, India.


texts:
Going back the genealogical lineage from present humans to the beginning of life, what was the biggest - in terms of body size or mass - animal in this sequence?

More generally, what would a time vs. size graph look like? Obviously the first ones were tiny microbes, but do we have "deep valleys" and high peaks one after the other? I know that our ancestors at the time of the dinosaurs were very small rodents. Were there some even smaller ones earlier (not referring to the microbes)?


texts:
A person may have a cold or any other disease that is an airborne-infection.
Is their sperm also contagious? Should the person take any precautions?


texts: What chemicals/substances exist in green capsicum (peppers) that do not exist in red capsicum?

texts:
I have known 3 people in my life that have incredibly adverse reactions (one called it an "allergy" and his symptoms did resemble such) to consuming any form of green pepper (capsicum) but have no problems with red peppers (also capsicum). Besides the obvious chlorophyll -- which I rule out since none of these friends had issues with green vegetables -- what else is unique to the green peppers that could possibly cause such reactions?

My limited understanding is that green and red peppers (at least with bell peppers) are actually the same peppers at different stages of maturity. If that is true what changes within the plant during the maturation process?


texts:
Most microalgae have rigid cell walls.

Dunaliella Salina is a pretty famous example of an algae with no cell wall, but just a plasma membrane.

Are there any other microalgae without a cell wall?. I have researched but I can only find Dunaliella being mentioned.


texts: Identifying a shrub with unusual "many shoots" growth behavior

texts:
While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:

On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.

We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:

So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.

Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.

Anyone know what plant this is, or what this growth behavior is the result of?


texts: Can a vaccine or antidote be administrated via gases or sprays?

texts: On TV or in movies a gas or spray containing a vaccine/cure/antitoxin is released and everybody is saved. Is this something plausible in real life? Specific examples would be appreciated.


texts:
Which of the following methods would yield the most purified protein fraction?

A. Salt precipitation

B. Charge separation

C. Affinity purification

The first one is the most commonly used, is it the best ?


texts: Expressing bacteriophage in mammalian cells

texts: Is it possible to express bacteriophage in mammalian cells by codon optimization? Any relevant literature? thanks in advance.


texts: Would it be correct to state that any biological difference between the sexes has to be found in the Y chromosome?

texts:
If the reason Why Men Don't Listen and Women Can't Read Maps is genetic, then one of the genes in the Y chromosome is to blame and in theory could be identified.

Correct or incorrect?


texts: Is there an acceptable term for 'male fox' other than 'dog'?

texts:
I'm writing a lab on sexual dimorphism in Arctic foxes. As such, I use the words 'dog' and 'vixen' fairly often. In the discussion section, I compare the results from the lab with the results from research on other animals. The most relevant research I consider pertains to dimorphism among dogs (Canis lupus: the kind we keep as pets and their immediate relatives).

The term 'dog' denotes a subspecies of Canis lupus, males of that subspecies, and male foxes.

There are ways to disambiguate what I'm writing, but none of them are elegant.

I'm considering using 'tod' or 'reynard' instead. Are either preferred in biological writing? If not, is there an alternative?


texts: Have there been multiple aboriginal species of dogs?

texts:
In "Variation under Domestication", Darwin writes that:

  I may here state, that, looking to the domestic dogs of the whole world, I have, after a laborious collection of all known facts, come to the conclusion that several wild species of Canidae have been tamed, and that their blood, in some cases mingled together, flows in the veins of our domestic breeds.

From this, I understand that several species of dogs evolved independently and half-civilised man tamed them later on, but I want to confirm this. Does Darwin argue that there have been multiple species of beings that resemble the shape of what we now call "dogs", or that there has been one meta-species of aboriginal dogs, which branched off into several wild varieties?


texts: Calling for Free Online Data for Paediatric ECG?

texts:
I need free online data about heart murmurs to study these:

  heart murmur frequency , S2 heart sound frequency and its split,
  murmur timing, and duration, murmur intensity, S3 sound presence and
  intensity, S1 presence and intensity, presence of ejection sounds and
  arrhythmias

I will cite your source then if I can use your data freely.

I would really have the same data as used in this paper:

  Heart energy signature spectrogram for cardiovascular diagnosis
  Vladimir Kudriavtsev, Vladimir Polyshchuk and Douglas L Roy

No pediatric ECG data here

beecardio (aggregation of many ECG databases)

Does anyone have simple data for my task?

I remember that some CD of some book has some standardised nicely organised sounds that you can use freely.


texts: Spironolactone's role with adrenergic agents in heart failure?

texts:
I am studying the treatment plan of adrenergic agents for heart failure.
Then, in the group discussion, spironolactone was included.
But I cannot understand how it is relevant when considering adrenergic agents for treatment of heart failure.
It is probably that it was only mentioned because adrenergic agents are usually used in combination with ABC therapy (antiplatelet, beta blockers, ...).
This includes also diuretics.

Spironolactone is diuretic and antihypertensive.
But I cannot understand how one can classify it adrenergic.

What is the role of spironolactone with adrenergic agents in heart failure?


texts: I have read many articles on bacteriophages (like the lambda phage1) being used for transferring genes into mammalian cells, but none of them mention any sort of lysis of the cells even though in bacteria, lysis would occur. Of course, killing the cell would beat the purpose of the gene transfer, but why doesn't the bacteriophage kill the mammalian cells? Has there been any research on lysis of the mammalian cells with phages?


texts: What are low-accumulating genotypes? And how does it differ from high-accumulating genotypes?


texts: Could someone recommend a book for surveying species?

texts:
I'm trying to get/renew basic knowledge of species. Could someone recommend a book for surveying "important"/"representational" species? I am looking for a book with good illustrations and that covers most "important"/"representational" species.

I am currently reading The Tree of Life: A Phylogenetic Classification, and it is thicker than I want to read as a first book in this kind.


texts: Could you force meiosis in a cell that normally uses mitosis

texts:
I've read in the red queen something that suggests the DNA repair mechanisms are better in meiosis than they are in mitosis.
I was wondering if occasionally we could force some of our cells that use mitosis to use meiosis so as to clean up mistakes in our DNA.


texts: I think this is a spider. 8 legs, 2 body sections, and 2 really long Palos? Anyways, can anyone identify this bug, or point me to a resource where I could classify it?


texts: In the metabolic pathways, each of the reaction needs an enzyme(protein) in order to occur successfully. Is there any quantitative measure that can be associated to this enzyme? Like synthesis rate of enzyme, degradation rate, mRNA transcription rate, enzyme activity, amount of enzyme present per unit measure of protein in the cell and if there is rate of generation of the enzyme's product, the rate of production of this enzyme in the human body, etc? I wanted to know the list of features that can quantify enzyme activity in the cell.


texts: Does a theory exist for the formation of thylakoid structure?

texts: I'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to be fairly large gaps in between folds?


texts:
What is significance of curve at point where lips meet, how it is determined and what effects it has on attraction and other factors? For some people it is a downward curve, for others it's an upward curve, while for some it is straight.

Is it genetic?


texts:
I know some animals don't have the required vocals. But, I do think that some like parrots, etc may have the capability to produce speech and talk just as we do.
My question is that if an animal is trained from birth, spending all the time around only humans, in the initial years of growth when their brains are much into learning everything, can they learn to talk just as we do?


texts: Why doesn't the sperm die if there is citric acid and acid phosphatases in the semen?

texts: While studying I read that sperm needs alkaline medium for its survival.But when I studied the composition of semen it revealed that semen contains citric acid which acts as a sperm nutrient along with fructose.It also contain acid phosphatases.So in such sitution how can the sperm survive?


texts: Does cell compartments and cells shell have the same meaning?

texts: I encountered these two words today. Do they mean the same thing? Does a cell shell and cell compartments refer to a cell that has been emptied of its DNA?


texts: Why do we add salt when precipitating DNA?

texts: All the DNA extraction protocols I have seen involve adding salts to the extraction buffer. What is the purpose of the salts? What happens if they aren't included?