texts: What directs macromolecules to their cellular locations

texts: For example I know that after transcription a mature mRNA is sent outside of the nucleus through the nuclear pore and then it goes to ribosome. But as for the free floating ribosomes that are out somewhere in the cytoplasm, how does the mRNA get to those organelles? Is there something else that attaches to the mRNA to help it? Even then I don't understand what force is helping a large molecule (mRNA) find and even larger macromolecular assembly (the ribosome).


texts: How do insects recognize their host plants?

texts:
Many insects, like butterflies have specific host plants on which they feed or lay eggs. While researching about some butterflies, I found that they lay their eggs on certain specific plants and their larvae feed on the leaves of those plants. I wonderd how do they recognize those specific plant species:

Do they use visual cues to find or recognize these plants?

Or

Do they use chemical cues, like sensing volatile compounds released by the plants? I think this might be possible as I found many species of butterflies prefer plants of the citrus family which contain essential oils. Do they just sniff around following the trails of such chemicals to find the host plant,

Or

Is it the combination of both?


texts: If during exercise the affinity of oxygen for haemoglobin is decreased, what are the general consequences for tissues?

texts:
During exercise more respiration occurs, and hence more oxygen is required.

So the oxygen dissocation curve is shifted to the right.

So at a given Oxygen partial pressure, the haemoglobin is less saturated with oxygen, i.e. haemoglobin has less affinity for oxygen.

What is confusing me is that the role of haemoglobin is to move oxygen around the body, so if it has a lower affinity for oxygen, won’t it compromise this function? Even though more oxygen is released, doesn't the haemoglobin have to carry it to all the tissues in the body? So how is this change in affinity of benefit if it reduces the oxygen subsequently available for other tissues?


texts: Do cats ingest everything that they lick off themselves during grooming?

texts:
Cats are well-known for licking themselves clean, but what happens to all the loose hair and sand and mud and wet substances that the lick off themselves? Do they ingest everything? Do they cough up and vomit out a furball later with all of this?

I have a pet cat and I've never understood where all that she licks off herself is going.

How is a cat's digestive system suited to handle all the inedible environmental substances?


texts: How is it possible to breathe perflurocarbon?

texts:
I have heard of liquid breathing, where an organism, usually a person, would be breathing in perflurocarbon. Now I looked up perflourocarbon on wikipedia and I noticed, no oxygen at all, but fluorine that would rather bind to the molecules inside you and kill you. I mean, fluorine is electronegative enough to oxidize oxygen. So why doesn't perflurocarbon fluoridate every oxygen molecule in your body preventing your cells from working and form calcium flouride in your bones?

How would a person not be killed by breathing perfluorocarbon? Is oxygen more soluble in perfluorocarbon? Does perfluorocarbon not even get into the blood and instead stay in the lungs? And even then, why wouldn't the oxygen coming in be turned into oxygen fluoride? Is it simply because oxygen flouride has such a short half-life, especially at body temperature that it never forms in significant enough amounts? But even then you would still be breathing out fluorine gas of which some will come back in the next breath. Fluorine gas is toxic because it is such a powerful oxidizer that it will oxidize anything.


texts: What does a female mosquito need from blood?

texts: I have come across many articles stating that female mosquitoes suck blood from vertebrate hosts to develop their eggs. Some also state that they need proteins, carbohydrates, iron etc., from human blood. But none of them (as far as I know) have stated what components exactly are needed from blood for their egg development. If proteins, what kind of proteins?


texts:
I am not a biologist. Please pardon me, if my question does not make sense.

I am trying to obtain a DNA sequence for pattern analysis in Matlab. I used to generate random sequence randseq in Matlab. However, I am trying to obtain some real dataset.

Any idea where I can obtain the DNA dataset. I am looking at a dataset having acgt patterns

Thanks

EDIT : Thanks a lot guys, I found it here. : http://www.ncbi.nlm.nih.gov/nucest?term=((human%5BComponent+Accession%5D)+AND+normal+Breast+gene+sequence)+AND+1000%3A10000%5BSequence+Length%5D


texts: Is it necessary for spiders to both wrap the prey in silk, and inject them with venom?

texts:
I stumbled upon the following paragraph on the Wiki page about Argiope bruennichi:

  When a prey item is first caught in the web, Argiope bruennichi will
  quickly immobilise its prey by wrapping it in silk. The prey is then
  bitten and then injected with a paralysing venom and a
  protein-dissolving enzyme.

On hindsight, it seems a bit redundant to do both those things. If prey is caught in the web, which is rather sticky and therefore restricts its movement, isn't it possible for the spider to go right ahead and inject venom?

Or on the other hand, if it wraps and immobilises the prey in silk, wouldn't it be more logical to then leave it to die, from some sort of evolutionary standpoint of wanting to saving energy and resources?


texts: Help me identify this insect from Bangladesh

texts: I have seen this insect flying literally everywhere in Dhaka city (Bangladesh) over the last two months. It's small -- around 1-1.5 inches long. It's not an agile flyer and can be easily grabbed by hand during flight.


texts:
I have been taught that yeast can act only on simple sugars (monosaccharides) and breaks them down into ethanol and CO2

I also know that yeast can break down maltose (disaccharide) and maltotriose (trisaccharide) using maltase from its enzyme complex (zymase) into monosaccharides of glucose and then ferments the same.

My question is whether yeast can directly ferment maltose and maltriose WITHOUT first breaking them down into glucose?  If so how is it done - enzymatically and what is the chemical equation


texts: How does the immune system "learn" from a vaccine?

texts:
According to Wikipedia:

  A vaccine typically contains an agent that resembles a disease-causing
  microorganism, and is often made from weakened or killed forms of the
  microbe, its toxins or one of its surface proteins. The agent
  stimulates the body's immune system to recognize the agent as foreign,
  destroy it, and "remember" it, so that the immune system can more
  easily recognize and destroy any of these microorganisms that it later
  encounters.

Question:  How does the immune system ""remember"" a foreign agent introduced via a vaccine?  And how does it learn how to deal with subsequent encounters?


texts:
Addiction and addictive traits seem common amongst animals.  A pubmed query shows it's been studied in everything from humans to worms.

My personal favorite of these is: "Individual Consistency of Feather Pecking Behavior in Laying Hens: Once a Feather Pecker Always a Feather Pecker?"

Is there/was there something adaptive about addictive behaviour?
Alternatively, how it is that addictive behaviour survived/persists if it is not adaptive?


texts:
I've been unable to find anything on the Google resembling this bird. I took the photo in Virginia Beach, VA around 2010, October, I think...
It appears to be between winter and summer plumage but I'm not sure. I tried looking on whatbird.com but couldn't find anything that really seemed to match up well.

Edit

I've added some more photos since people seem to question whether or not the white is snow, for some reason. Also note that most seem to have a red bill with a black tip, while the one with more white on its breast has a largely black bill with just a red band. Do bills change colors when plumage does, is that a thing, or perhaps it's just an anomaly or a gender trait?


texts: Can pheromones in perfume be formulated to cause agitation?

texts:
I generally don't care for female perfume. I have very sensitive olfactory receptors and in general, I just find perfume overwhelming.

A couple weeks ago, my wife of almost 14 years and I were shopping. As has happened many times before, she asked me to smell a perfume (Play it Rock by Playboy) to see if I liked it. Shockingly, on first whiff, though still overwhelming, I quite liked it. So she bought it.

Now, when she wears it, I do find the aroma pleasing, however I find myself getting quite agitated, depressed and even overcome with jealousy and paranoia.

Obviously, there are lots of psychological factors in play :

Perfume's primary purpose is to arouse and attract men
She almost only uses it when there are going to be other men around
It is playboy, subtly indicating the promotion of promiscuity

However my internal reactions are so intense I can't help but conclude there something more physiological triggering/intensifying them.

Could the perfume's pheromones be slightly misformulated to cause
this reaction?
Would the same pheromones that arouse a man also inherently trigger the fear of the arousal of others?
Is it possible that my pheromone "sense" is also heightened like my sense of smell, causing an abnormal reaction specifically in me?

Note : I can't find official documentation that the playboy perfumes apply pheromonology (Yes, I did just make up that word), but I have found them listed by other sources in sections of perfumes that do, but Playboy perfumes seem to be priced drastically less than the rest of the pheromoned perfumes.


texts: What are the highest and lowest amplitude values in ECG for humans?

texts: I'm currently trying to parse the records captured from an ECG device and display them on a mobile application. I am wondering what the highest and lowest possible amplitude values for ECGs are in humans? What may happen if they exceed those values?


texts: How does the new discovery that mitochondrial dna is inherited from both parents change population genetics and other dates?

texts:
This new study seem to have pretty much proven that mtDNA is inherited from both parents. I assume that this would lead to most age estimates of ancient human populations that heavily depending on mtDNA, being discarded. Is this right?

What other things would be affected by this discovery?


texts: COVID-19 infection data when partitioning to communities

texts:
Suppose we think of the disease in a certain country as follows.
We have a set of "communities" $C_1,\dots,C_k$ in the country where $k$ is some small constant, say $10$. Each individual is a member of exactly one of the communities.
The communities can be simply a partition of the entire population into groups of ages, races, cities, economical situations etc.
In each point in time there are $R_{i,j}$ for each $i,j\in[k]$ (which seems to be closely related to the infamous $R_0$). $R_{i,j}$ is the excepted amount of individuals in community $j$ that a sick individual from community $i$ is going to infect. Note that, not necessarily, $R_{i,j}=R_{j,i}$.
So, $R_{i,i}$ measures the infection inside the community, while $R_{i,j}$ for $i\neq j$ measures infections between different communities.
I don't know if this is relevant for here, but do you know of some data or estimates of such parameters $R_{i,j}$ from somewhere in the world using any partition?


texts: Is it a coincidence that the sensory systems for smell, vision, taste, and hearing are all near each other in the head?

texts:
I was wondering if it's an evolutionary advantage to have many sensory systems in a small place of the body, the head. This applies to mammals, reptiles, synapsid, dinosaurs... and many more.

My theories:

The distance to the brain is short and thus smaller time delay to
respond faster to the outside world,have more reflexes, hunt faster
prey and fight more accurately.
The short distance makes the "wire" (signal carrying) shorter and
thus less vulnerable to be cut from a injury, because for a organism
losing an eye reduces possibilities of survival dramatically.
In humans at least the head is the upper part, then vision organs
see more with less obstacles such as vegetation or terrain irregularities, or anything that obstacles vision, normally higher
means seeing more things. This I'm not sure applies so strongly to
smell. To taste, certainly not. To hearing, possibly a little,
thought nor much as vision.

We evolved from a common ancestor that was like that but that doesn't explain why it's not common to get out of that coincidence.


texts: How can humans taste saltiness in an aqueous solution of salt (saltwater) if the anions and cations in the salt are dissociated in the solution?

texts: This may sound like a dumb question, but I've always wondered why we can still taste saltiness in a dissolved mixture of saltwater. In an undersaturated, aqueous mixture of salt and water, the salt ions are completely dissociated from each other, meaning that the salt is dismantled into its constituent parts. If this is the case, then why do we taste saltiness when drinking saltwater and not taste the individual tastes of the constituent cations and anions? Why do we taste NaCl instead of Na AND Cl individually?


texts: What distinguishes Mendelian Inheritance from Non-Mendelian Inheritance?

texts:
I'm having some trouble determining what exactly is the difference between Mendelian inheritance and non-Mendelian inheritance. For instance, I understand that chromosomal abnormalities such as Down's Syndrome fall under non-Mendelian inheritance because they concern chromosomes, not single genes. And I also understand that Mendelian inheritance concerns single genes, as in Sickle-cell anemia (which is an autosomal recessive disorder).

What confuses me is the fact that our textbook discusses dihybrid and trihybrid (concerning 2 genes and 3 genes, respectively) crosses under the Mendelian inheritance chapter, when to me it seems like these crosses are non-Mendelian because they deal with multiple genes. However, Gregor Mendel did in fact use the dihybrid cross to deduce the law of independent assortment, so I'm completely confused. Could someone please clarify this for me? I'm afraid that I'm maybe misinterpreting something.


texts:
What is the definition of 'independent assortment'. I tried researching this term but came back with two results:

alleles assort themselves independently of different alleles
the alignment of homologous chromosomes is random along the metaphase plate; resulting in the daughter cell inheriting either maternal or paternal chromosome based on 50:50

Which is the correct term?


texts: Formation of disulfide bonds in protein expressed after transduction

texts: Say I transduce a nucleic acid sequence using a viral vector that encodes a protein having at least one disulfide linkage. For simplicity, let’s assume that there are only two cysteines in the protein and the side chains of these cysteines are close together when the protein is folded with the cysteines unlinked (reduced/thiol). Also assume that the cell being transduced is a eukaryotic cell (mouse or human). What is the chance that this disulfide will be linked (oxidized) when expressed by the cell? Does this happen pretty reliably? What might it depend on?


texts: Are MacAdam ellipses theoretically predictable?

texts:
MacAdam ellipses were found as a fit to experimental results on color matching by human observers. Multiple color spaces attempting to make euclidean distances more perceptually uniform, like CIELAB and CIELUV, are based on these experimental data too.

But what about theoretical side of the color distance question? Is current color vision theory able to predict sizes and orientations of these ellipses? If not, what are the obstacles?


texts:
I have found a large, wild patch, some 200m long, of mainly Datura Stramonium, in our street. I have always been keenly interested and well read on the shamanic, and - very rare - medicinal uses of this species, but scattered amongst them, like family, are two other plants I don't know, but am convinced are also some kind of Datura. I would please like some help on identifying the other two based on the two photos I have of all three.

This is the well known - to me - Stramonium flower, the plant characterized by jagged leaves and the well known spiked seed pod of Jimson Weed seeds.

It looks like user29734's answer is correct, and the above is Morning Glory, but of course subject to confirmation. I now do recognize at least the purple flower as Morning Glory, but from some 30 odd years ago. And it now looks like what I confused with Datura Alba is really just another colour flower of the Morning Glory.

If anyone could please confirm my ID of the Stramonium, and confirm the identification of the second image as morning glory, and suggest what species.

These plants are all around my neighbourhood, with is the northern part of Randburg, South Africa. This city borders on the Northern side of Johannesburg. 1 It's a temperate climate, with very hot and rainy summers, and bitterly cold and dry winters. The soil is reddish and lacks much humus.

It is a semi-rural area, having been rapidly urbanised over the last ten or so years, when it was still just farms and small holdings. Farming is mainly vegetables or lucerne; and lots of maize further out from the city. We are a few km south of the Cradle of Humankind.

1 Strangely enough, there are two cities in the US with the same names, both in California, I believe. I know Johannesburg is.


texts: What is the benefit of reducing inflammation when producing antibodies?

texts:
We just learned in lecture that IL-10 promotes the formation of plasma cells over memory cells. Which seemed strange to me as IL-10 also reduces inflammation, and I figure you would want inflammation as it will help antibodies reach the site of infection.

My question is, why would the body want to reduce inflammation and produce more antibodies at the same time?


texts: What are the biochemical processes occurring when food spoils?

texts:
Let's assume for a minute that microbes themselves and their direct toxic products (i.e. endotoxins) aren't toxic to humans. Let's also discount any innate immune responses the body mounts against the invading microbe (i.e. inflammation and production of cytokines).

What happens to food molecules (mechanistically) as it spoils and what deleterious effects do these "spoil products" have on the body if ingested? I'm looking for compounds that can result from the spontaneous breakdown of food or the byproducts of microbial metabolism (that is NOT a "direct" toxin) that is harmful to the body.

For example, do the proteins in food break down into some toxic nitrogenous substance?


texts: Organisms that contain rare chemical elements

texts:
By accident, I found a slide from a Polish chemical presentation, that talks about a small group of biological organisms which contain chemical elements not found in the human body, like:

B (boron),
F (fluorine),
Si (silicon),
V (vanadium),
Cr (chromium),
Se (selenium) and
Sn (tin).

Can someone provide a list of examples of organisms containing these chemical elements?


texts: copper vs aluminum, what's the safest for health?

texts:
I'm working on a mini project for a milk dispenser machine, using a peltier device to cool the milk down, I have to choose between a copper or aluminum cooling block (see pictures bellow).

But I'm worried about health issues in the long run, (oxidation and stuff), I have no idea what to choose.

What would you guys recommend me ?


texts:
Walking through the local established broadleaf forests dominated by oak and tulip poplar (Eastern U.S.), it is common to find patches of young tree saplings, say 10-20 oak or tulip poplar saplings growing in close proximity. The obvious restriction on living space means that probably at most one of these trees will make it to maturity. In fact, judging by the apparent lack of mid-aged trees of these types in the woods, it seems very possible that none of these trees will last much longer. I'm curious: at what point and how would these trees die? The answer might also help me take better care of trees I've planted in my yard.
I can easily speculate about some causes:

Competition for water/nutrients in the soil
Not enough sunlight
Animal predators
Pathogens

But these suggestions don't answer the how or the when. And it's not clear which accounts the biggest impact. Clearly, the above factors didn't prevent the trees from growing in the first place. And the first suggestion (competition for nutrients) puts a limit on their growth but doesn't say per se why a plant would die.


texts: Where does the number 67 in the nuclear protein/antigen Ki-67 come from? Why not 66 or 68?

texts:
I have read in in the original paper that in the year 1983 a research group in Kiel, Germany (that's where the Ki- in the name comes from) developed monoclonal mouse antibodies against Hodgkin lymphoma cells in multiple 24-well plates. If I understand correctly they were able to isolate antibodies from 63 wells and divided them into 493 microtiters into several 96-well microtitre plates. Of these 493 titres, 164 cell batches were chosen for further investigation and expanded. Somehow Ki-67 emerged from there, but why this number? Who gave it that name and why?

A teacher once told us in med school, the cells producing the antibodies were found in well 67, but I cannot find any source to back up that claim.


texts:
I am confused, can evolution ( speciation ) really occur in such a short time ?

  In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the South Adriatic Sea, to the neighboring island of Pod Mrcaru. Now, an international team of researchers has shown that introducing these small, green-backed lizards, Podarcis sicula, to a new environment caused them to undergo rapid and large-scale evolutionary changes."

Here is a short video featuring the scientist.

Two related articles:

http://www.sciencedaily.com/releases/2008/04/080417112433.htm
http://news.nationalgeographic.com/news/2008/04/080421-lizard-evolution.html

Edit: I asked a similar question previously about two people having 44 chromosomes and their possibility of creating a new species. You might like to read/answer that as well:

Can two humans with 44 chromosomes produce viable offspring?


texts: Viability of Toxoplasmosis oocysts on dry smooth surfaces

texts:
This is a weird question. My wife is terrified of contracting toxoplasmosis during pregnancy and I was hoping I could get an expert opinion here to potentially make her feel better.

She recently took the toxoplasmosis test and it came back negative. The next day, we cleaned the house. We have four cats, all indoors, who have intermittently gotten into the trash and licked containers containing raw meat or eaten raw meat that we had bought from the store. We also live in the city, no rats or rodents that they could find and kill. We keep our house fairly clean. There was a smear of dried cat poop hiding under a rug on our tile floor that I cleaned that has to be at least 5-6 months old. I had to really pick at it after spraying it to get it up. She's worried that because she handled the towel I used to clean it up with that she's potentially exposed herself to infection.

How likely is it that old, dried cat poop like that could still harbor viable oocysts? Assuming that it was infected in the first place. Do they dry out and inactivate if they're not exposed to moisture?

Thanks!


texts: Altruism in viscous (asexual) populations

texts:
The viscosity of a population is the tendency of offspring to remain
near their place of birth. Taylor 1992 ("Altruism in viscous populations") provides a model to study how viscosity affects the evolution of altruism in a patch-structured population. In Taylor's model, the marginal inclusive fitness is given by
\begin{equation}
  W = bR -c - s^{2}(b-c)R
\end{equation}
where $R$ is the relatedness of a mother to random offspring born on her breeding patch and $s$ is the probability the offspring will remain on the natal patch. The altruistic act creates $b$ offspring with average relatedness $R$ and $-c$ offspring with relatedness 1.

My question is about the term $s^{2}(b-c)R$. Taylor explains this term as follows:

  these b - c extra offspring remain on the natal patch with probability
  s and will therefore displace s(b - c) random individuals competing
  for the next generation breeding spots on that patch, and these will
  be native to that patch with probability s and in this case will have
  average relatedness R to the actor. Thus these displaced individuals
  will have average relatedness sR (p. 353)

My question is: Why is the average relatedness $sR$ (as opposed to $R$)? In other words, why is the term that accounts for competition among relatives $s^2(b-c)R$---as opposed to $s(b-c)R$?


texts:
I was always under the impression that the auditory hairs located deep within the ear, past the ear drum, are microscopic.

After taking a shower today, I was softly padding my outer ear with some tissue paper to dry any moisture, when some wax just got attached to it. What was unusual was that there were some hairs on it (3-5 perhaps, overlapping) that were about half a centimeter in length.

Are these just regular hairs that grow in the inner/outer ear? Or are they the ones that actually aid in hearing (the ones I thought were microscopic).

My question is to verify whether or not these hair shafts I observed are used in auditory perception. Either way, are these supposed to fall off?


texts:
I was walking outside (location: Netherlands) and just saw this little bird:

Unfortunately I had to take a long range picture with my cell phone so the quality is quite bad, however I hope still someone can identify this species. Personally I think it escaped somewhere as we have never seen it before and also did not seem to be scared of us.


texts: How do birds decide which branch to land on?

texts:
What factors do they weigh on? Shape, position of branch within the tree body/structure, fatigue, nearness to current position, etc.

And how fast does a bird's brain and nervous system decide on this?

Narrowing it down to a bird of prey, say the Harpy Eagle.


texts: Can a woman possessing 1 mutated allele show attenuated color-vision deficiency?

texts:
Women possess two X chromosomes. However, during development, when the embryo has about 32 - 64 cells, one of these chromosomes is randomly inactivated (in each cell) by an lncRNA named Xist. As a consequence, females are mosaics.

I was interested if this might affect phenotypes of X-linked genetic diseases, for example...

1) Is it possible for a woman who is heterozygote to color vision deficiency be "partially" color blind, considering that some of her cones will only possess the mutated allele?

2) Is it possible that a heterozygote female who carries a dominant allele for a X-linked disease be asymptomatic?

Any references on these issues are welcome.


texts: Why is Sanger sequencing inferior for detecting SNPs in cancer cells?

texts:
I am familiar with Sanger sequencing, but at the level of an undergraduate. A lecturer of mine tried to describe Sanger sequencing as losing the sequence information in noise when used to detect cancer. This paper also says "lacks sufﬁcient sensitivity for detecting mutant alleles in tumor biopsies,"(Thomas et al., 2006). What is it about Sanger that makes it too insensitive for SNP analysis?

Thomas, R.,K., et al. (2006) Sensitive mutation detection in heterogeneous cancer specimens
by massively parallel picoliter reactor sequencing. Nat. Med. 12, 852–855


texts: How does food intake affect medicine? Why pill instructions recommends taking them before (after) meal?

texts:
Even simple vitamins seem to have this in the instruction. Why is is so? Is there some simple model of how do pills interact with food? Does it depend on the food type? (What about drinks?)

Should not eating at all on some day be considered "before food" or "after food"?


texts: In theory how fast could nerve signals travel if the nerve fibre was perfectly insulated?

texts: My question is purely theoretical and my main aim is to find out the maximum speed that a nerve signal can travel within a nervous system and and whether this speed represents the physical limit of how fast a nerve signal can travel. This could also extend to designs not seen in nature and possible artificially designed nerves i.e. synthetic biology. Apologies for an awkward question!! Any input is welcome!!


texts: Do gene expression levels necessarily correspond to levels of protein activation?

texts:
I have seen a lot of research into molecular mechanisms of diseases/phenotypes use measures of RNA as a 'proxy' for the level of protein available in the cell. Is this actually valid?

My problem with the assumption that RNA levels correlate with that of the active product (i.e. the protein) is that a lot of post translational regulation occurs, including co-factor binding and phosphorylation, to name but 2. Does anyone know of any studies that have looked into the correlation between RNA levels and protein levels, and separately into the correlations between RNA levels and active protein?

It makes sense to me that RNA would correlate with protein certainly, but whether this relates to the proteins active function is what I wonder - i.e. there could be a pool that is replenished as and when the protein levels drop, but the proteins are only actually active for short periods in response to specific stimuli. So, does anyone know of any studies that have looked into the correlation between RNA levels and protein levels, and separately into the correlations between RNA levels and active protein?

Update (04.07.12)

I have not accepted any answers as yet because none address my question about levels of protein activation, but I concede to Daniel's excellent point that proteins are not all activated in the same way; some are constantly active, some require phosphorylation (multiple sites?), some binding partners... etc! So a study looking at 'global' activation is not yet possible. Yet I was hoping that someone may have read some specific examples.

I today found an unpublished review by Nancy Kendrick of 10 studies that have looked at the correlation between mRNA and protein abundance - still not relating to activation. However she finishes the paper as follows;

  The conclusion from the ten examples listed above seems inescapable:  mRNA levels cannot be
  used as surrogates for corresponding protein levels without verification.

If this is her conclusion about protein levels, then any correlation between protein activation and mRNA abundance seems unlikely (as a rule. Some protein levels do correlate with the RNA - see the paper).

I am still interested in any answers that give any information about specific examples of protein activation and mRNA levels - it seems highly unlikely there are no such studies, but I have been as yet unable to find any!


texts:
In all electronic devices with the possibility of saving there are tiny magnets that can store your data by the state they are in. In general, there has to be something changed to store information and independent observer should be (theoretically) able to read all the stored information just from one state of brain.

I think keeping some signal in circuit would be really nutrition expensive (through the ion pumps that create the electro-chemical gradients).

So how does a brain store the information?


texts: How ants handle the huge "data" from multiple pheromone trails?

texts: We know that every single ant produces pheromones to communicate and inform others. When there are millions of ants, how do they handle that many signals without getting confused?


texts: How are melatonin levels measured in humans?

texts:
I'm wondering how it is possible to measure diurnal variations of melatonin levels in humans. I keep reading that there should be a large difference in amplitude between melatonin levels measured at night and in the middle of the day.

Have there been any studies of melatonin levels in humans where I can take a look at the methods they used for this kind of testing and/or see sample results?


texts: Is there any other sources of hydrogen carriers for the Electron Transport Chain other than the 3 main metabolic pathways?

texts: I am learning about the 4 main metabolic pathways for cellular respiration. I learned that NADH and FADH2 hydrogen carriers are essential in the Electron Transport Chain, because they deposit their hydrogens (which consist of protons and electrons), which are used to power ATP synthase (reattaches ADP and Pi together to form ATP) in the inner mitochondrial membrane. The reduced hydrogen carriers must come from glycolysis, pyruvate oxidation, and the Krebs cycle. I'm wondering if all those pathways were inhibited (and essentially broken completely) let's say, is there any possible way for the Electron Transport Chain to get hydrogen so that it can still work?


texts: I design my primers in Primer3PLUS and analyze them in Oligoanalyzer3.1, A big problem that I have this is that I got very nice output in NCBI-Primer BLAST for their specificity but a very negative ΔG for self or hetrodimer even under -7 or-13. is it possible use them for PCR by adding DMSO or Formamide? what other way may be helpful?


texts:
This big fellow came to visit my kitchen (in Hong Kong) a bit earlier.
It is brown with some longitudinal white stripes, banana/boomerang-shaped patterns towards the middle, and an eye-like marking on each forewing tip. Picture below.
What kind of butterfly is it?

I helped it find the exit in the meantime, not before taking a lot more pictures.


texts: Can you disconnect sensation from the brain without destroying muscle functions?

texts: I want to know if it would be possible for a surgeon to "shut off" a person's senses without causing paralysis of any kind. The person would have to maintain their ability to speak and move, but not be able to hear their own voice or sense the physical world around them at all.


texts: Are there certain symmetric-pair muscles that are slightly bigger and NOT due to handedness?

texts:
Ok, hear me out, I was just thinking about an article in Nature I read in the past titled "Scrotal asymmetry in man and in ancient sculpture"$^{\dagger}$ and more recently an entire medical textbook detailing everything about hands wherein the author accounts the different types of blood vein topology categories there are in humans, and he touches on handedness too. The part about handedness stuck with me, and I began to notice (looking in the mirror, etc.) that my right neck muscles are slightly larger than the left ones, but so is my friend's who is left handed. I thought this might be due to handedness not translating to chewing behavior (chewing on the right or left predominantly). Anyway, all this is building up to my main question which is this:

  Is there something about our anatomy (organ placement, vein topology, etc.) that makes certain symmetric-pair muscle groups unavoidably asymmetrical or is it just handedness or the environment?

$\dagger$ Heard about it here: https://www.youtube.com/watch?v=Xyquv6SsLWg&t=0m56s


texts: If i am right, then any category placed at any rank in the taxonomical hierarchy is a taxon. For example Panthera, Mammalia, Solanaceae etc. But are general group of organism (casual groups which are not biologically defined like Birds, Cats, Fishes) also regarded as taxa? Please clarify.


texts:
I know that ethanol increases insulin secretion--could someone explain why?

All I have found till now is experimental data analyses.  I am interested in mechanism of alcohol consumption.


texts: What would be the effect of excess taq polymerase on the PCR?

texts:
I just had one question regarding the possible effect of putting to much Taq polymerase in my PCR tube?

Instead of 5µl I put 50µl (10x more).

Do you think it will have a bad effect on the reaction??

Thank for your help.


texts: How are smell and taste in fish differentiated?

texts:
The senses of taste and smell in different fish classes are described as two distinct senses; smell is mediated by the nasal openings, and taste by epithelial taste buds.

They are both forms of chemoreception and therefore it is not clear to me what intrinsically defines them as two distinct senses. The more so because reception of chemical substances is mediated by water.

What defines them as different senses? Is it only the difference of receptors that defines them as two distinct senses, or are there other reasons to differentiate them?


texts: Why do Great White Sharks not survive in captivity?

texts:
Keeping any large marine predator in captivity is a challenge. While it has been done with both mammals and some sharks, it has never been successful with Great White Sharks. The longest a Great White Shark has survived in captivity is something like 4 – 5 weeks, if I am not mistaken.

I have heard this can be because they are used to swimming such great distances in the wild. However, both Killer Whales and Dolphins also swim great distances per day in the wild and are known to survive (sometimes even breed) in captivity.

So why is it that Great White Sharks are so hard to keep in captivity?

I am aware that most large predators kept in captivity live less long than in the wild, with some the exceptions (crocs just chill). It just seems extreme to me that Great White Sharks die within such a short period of time.


texts: Why is hydrofluoric acid so dangerous if it is a weak acid?

texts: I've read that hydrofluoric acid (HF) is extremely dangerous to touch, but what exactly makes it so toxic? It's weak acid ($K_a = 7.2 \times 10^{–4}$) and dissociates approximately 1/1000 as much as Hydrochloric acid does in water, so why is it so much more dangerous? Wouldn't a stronger acid cause more damage? What exactly happens when human skin comes into contact with Hydrofluoric acid that causes it to be so lethal?


texts: What is the name of the bird which feeds on penguin blood and meat in Tristan island?

texts:
I just watched a National Geographic documentary "Unseen Islands: Atlantic Arks" and there was some thing strange in Tristan island. Some small bird which changed its diet to feed on the blood and meat of the penguins on this island.

I want to know more about this bird - or its name so I can search it - and if there are other examples of this behavior of changing diets.


texts: What is the difference between then?I have read some jobs that describes analysis about mutations rates and another ones with evolutionary rates.I want to know the diferrence between then.


texts:
Can you recommend a good, detailed book on how plants function? A book that explains plant processes on a molecular level from roots up to the fruit.

I am interested in home crops production, such as tomato and peppers, but I expect the principles to be the same for most of the plants. There are lots of "how to garden" books, but this books don't explain things, they just tell what to do.

Background: I have a degree in chemistry so I am confident in my knowledge of chemistry and chemical analysis. But this knowledge is useless unless you mixed it with other science branches, such as biology.


texts: How would one determine whether a chemical will upregulate a certain class of proteins?

texts:
I'm trying to determine whether certain organic chemicals will upregulate classes of proteins that possess deacylase activity.

How would I go about this experiment? I'm assuming I would use some sort of assay but I'm not exactly sure how I'd go about it.


texts:
In this paper, the cuffcompare RNA package is reported:

  Because of the stochastic nature of sequencing, assembly of the same
  transcript in two different samples may result in transfrags of
  slightly different lengths. A Cufflinks transfrag was considered a
  complete match when there was a transcript with an identical chain of
  introns in the combined annotation.

What does this mean in terms of comparing two transcripts to see if they are the same? Does that mean two transcripts are considered equal if they have the same introns, even some exons are missing in one of the transcript? What do they mean by transfrag? Is there an example?


texts: How do cancers eventually lead to death / other debilitating symptoms?

texts:
With regards to people I know or have read about who live with cancer, most of their symptoms are results of chemotherapy, surgical interventions, etc., which have the goal of eradicating the cancer. Assuming the cancer went untreated,* what kinds of symptoms would the cancer itself lead to, and by what mechanism would it cause death (in most cases)?

Please excuse my ignorance. I know that every cancer is different, and even different cases of a single type of cancer can present differently; so there may be many different answers to this question, but I'm not sure if they eventually lead to the same thing.

*I'm asking purely out of curiosity – I'm not "opposed" to chemotherapy or anything like that.


texts: How can a species switch from r to K - reproductive strategy in a single generation?

texts:
I ask because it seems as though humanity is in the midst of doing exactly this. Only a few decades ago, human population was growing exponentially, and it seemed destined to keep growing until hitting constraints of food supply, at which point we would devolve into resource wars and famine. But then it didn't happen -- over the last few decades, fertility rates in the developed and developing world have plummeted and the world population is expected to stabilize in the second half of this century around 10-11 billion people. Demographers list a number of reasons for this -- education and empowerment of women, urbanization, decreased child mortality and increased life expectancy, availability of safe and effective contraception, etc. The common thread is that these trends encourage people to invest more into fewer offspring. It's as though our entire species is spontaneously deciding to switch from an r-strategy of reproduction to a K-strategy.

My question is whether this is unprecedented or not. I had the impression that r or K strategy was typically a function of species, but here we have a case where humans seem to be switching between the two strategies in a single generation. Are there other species which can change their entire reproductive strategy when the population approaches its carrying capacity? If so, what kinds of environmental cues or epigenetic factors trigger the switch? How do they manifest themselves in the case of humanity's current switch?


texts: Can anyone please determine if this is a moth or butterfly and what its name? We found it near a waterfall in the Philippines. There's actually a bunch of them and it seems that it's their natural habitat which is close to the waterfall and a stream along.


texts: Do pet animals and humans perceive good and bad smells differently

texts: As the title says, just wondering if there is a difference in what animals like dogs and cats perceive as good smell vis a vis humans. Example : Smell of some flowers - great . Fart smells - bad.


texts: How does the zygote divide much faster than other cells?

texts:
Normally a cell has a mechanism that controls its division. As far as I know, it checks surface area and stuff like that to decide to go for mitosis or not.

However, this is not the case for a zygote. A zygote, after around ~14 days starts to divide rapidly and forms the blastula. What mechanism controlls this "rapid division"?
Why can zygote divide rapidly when it has not reached a high surface area or doesn't have enough mitogens to induce the cell division? Does the zygotes mini-cells have a cell cycle like other cells but they are really fast? Or do they just copy the DNA and divide rightaway?

And when I first saw the video of this stage, I was surprised. The DNA is a one long molecule; how fast do those replicators work?


texts: Is it unusual for a child to be diagnosed with diabetes?

texts: Recently, I came to know that a boy in my town who is 6 years old is diabetic and many people were shocked from this news.


texts: Where does female ejaculate actually originate from?

texts: It's common knowledge that it's released via the urethra, but where does it originate? If it doesn't come from a part of the clitoris, then why is the clitoral glans called the clitoral glans? How does it travel from the originating spot to the urethra?


texts: Question about cytoskeleton coordination

texts:
I am trying to study for a biology and I am having some confusion over the following topic. Can anyone help explain/ shed some light on the concepts of Rho family GTPases. Is it true that we have Rho activates forimins to relieve  auto inhibition of actin filaments while Rac promotes lamellopodia and Cdc42 works on the leading edge and fillipodia?

Secondly, how are the microtubules involved in cytoskeleton coordination? Do they simply affect Rho and Rac concentrations. How else is the concentrations of these spread throughout the cell as to maintain distinct concentration gradients?

Thank you all for any help!


texts: Is there one centomere for the two chromatids in a dyad?

texts:
I have no explanation for this. It is all I have to ask.

Thank you


texts: Ways to identify/distinguish individual coyotes?

texts:
Are there any methods to distinguish individual coyotes from a distance (with a binocular or telephoto lens)? Are there marks or patterns we could be looking for?

Similarly, if I have seen a coyote at the same location multiple times, what should I look for to see if it has been the same coyote?

I've been searching about it and only found ways to distinguish individual wolves.

Thanks!


texts: Phylogenetic algorithms: How to interpret multiple ML trees from the same dataset?

texts:
There's still something that confuses me about how many of these algorithms work, and how results are presented in the literature.

Let's consider a Maximum Likelihood based algorithm like MrBayes or RAxML: Users set a random number seed which generates the starting tree. For many of our datasets, different seeds which result in different ML results, as the algorithms are initialized with different trees.

I'm not entirely sure how one is supposed to interpret this, especially as my experience with ML methods is that the initial step is irrelevant to the global/local min/max in parameter space----the chains just take longer to converge.

How should one interpret these results? Are users to run 1000s of trees at different parameter values, and then chose the most optimal likelihood value? That seems rather ad hoc, as does bootstrapping, etc.

Is the dataset fundamentally flawed?


texts: Why do we absorb vitamins better from whole foods than from pills?

texts:
We can't rely on pills to provide us our nutrients because we don't absorb the nutrients from the pills as effectively. Presumably this is because pills are lacking components that are required for certain reactions to take place.

Why can't we just create a pill that does have all the necessary components?


texts:
My professor says

  Nervus troclearis IV somatomotor fibers supply musculus obliquus superior.

and similarly for nervus oculomotorius III

  Nervus oculomotorius postganglionic fibers supply musculus ciliaris, m. sphincter pupillae.

I understand the verb "supply" as "stimulate" or "allow signal pass from the tract to the muscle that contracts or flexes". However, fibers must have some other functions too. So the verb supply seems to be a general term for these functions.

How do fibers control the muscle?


texts: Will carpenter bee larvae die if trapped or find a way to bore out?

texts: I had a carpenter bee problem last year, beginning with the awful sounds the larvae make! The exterminators couldn’t find the bore holes (they were/are inside a gap between top of the foundation and sub floor of what was once a garage).  I eventually hired a contractor, who removed the vinyl siding, and discovered a straight line drill hole up the plywood!  He replaced plywood and insulation, saw no other evidence (except two dead bees), and sealed up the gap. It’s now spring, and I am hearing them once again.  My fear is that there is a gallery in a floor joist. If there ARE larvae and they ARE there, will they eventually just emerge into that now sealed up gap and die, or bore their way through where it was sealed or, worse yet ~ my floor?  Thank you.


texts: Variance of frequency in expanding populations

texts:
I'm trying to understand the variance in frequency of some strain after some time as passed in a growing population. The idea is to then plug this in kolmorov foward equations and get the classic results (probability of fixation, time to fixations, mean fitness).
However, I got a weird result.

I started with the model definde here

$N(t) = N(0)W^{t}$

and from the answers I got that the variance of $N(t)$ would be

$\text{Var}[N(t)] = N(0) W^t(W^t-1)$

Now, the frequency of strain $N_{m}$ is

$f_{m}(t) = \dfrac{N_{m}(t)}{N_{m}(t) + N_{b}(t)}$

assuming only two sub populations. From there I need only the variance of $f_{m}(t)$ and this and this helped me build a formula. However, the variance of the frequency is not $0$ when $f_{m}(0) = 1 $ and it has units much larger than 1...

My question is, have I done something wrong?


texts:
Background : Certain plants have been genetically engineered to have sense-antisense gene of a parasitic nematode. The dsRNA produced by the plant then inactivates the mRNA produced in the nematode, who, then isn't able to synthesize the corresponding protein and dies as a result.

Question : How is the dsRNA from the plant transfered to the nematode's cell ? By transformation ?


texts: Can humans derive any nutrition from eating the bones of animals?

texts:
Bones contain many nutrients like Calcium and phosphorus.

And I'd take a guess that some kind of bones like bones of a chicken(hollow) aren't dense enough to be much of a  problem during digestion.

So,is there any benefit in eating for example say chicken bones?


texts: What is the attacking mechanism of RF on IgG?

texts:
Rheumatoid Factor (RF) attacks Fc portion of Immunoglobulin G (IgG), I want to know the underlying mechanism at molecular level. Also, what type of bond or attachment is made by RF and Fc portion of IgG?

// I'm a student of mathematical physics and have no detailed knowledge in biology, this question comes in my mind because my sister is suffering from Rheumatoid arthritis. All I want is to understand this disease from physical aspects//


texts: How does UV light damage the DNA when the chromosomes are deep inside the cell?

texts: When UV light falls on the skin it has to go through the cell membrane and the nuclear membrane to reach the chromosomes. So it looks like that the DNA is protected but it probably isn't. Won't membranes be damaged first and the so that the cell dies before the DNA is affected and is replicating wrongly (if it is damaged too)? Or is DNA just really much more vulnerable than cell membrane?


texts:
As we get older, we tend to lose our sweet tooth and become more tolerant to bitter foods, like vegetables. However, I never understood how this works. Why is it that children prefer sweeter foods, even some that adults may consider "too sweet"? In fact, is there any reason they would also dislike bitter foods, even when they can be beneficial to their health?

This just seems bizarre to me that the body would start out craving sweets and lose this later on. Are only humans like this? Is there anything suggesting that younger animals prefer sweet foods too, but like them less as they get older? Does this have any biological advantage or is it just random?


texts: Could someone please identify this species?

texts: I have come across these insects a lot more lately, as far as I can tell, they can sustain a hover state in flight. I'm actually quite interested to know what these are, seeing they look like a cross between a bumblebee and a common housefly...


texts:
I just started reading about recombination frequencies of genes and related stuff, and can't find an answer to this (possibly naive) question.
Can recombination possibly "kill off" a gene ?

To be more specific, say a gene is located at position $x$ to $y$ on some chromosome.  Then, we are so unlucky that recombination decides to cut off the chromosome at location $x + (y - x)/2$, right in the middle of the gene.
So both halves will get recombined with the other halves of the gene on the homolog chromosome.  If the allele on this chromosome was different, could it result in destroying both alleles of the gene ?  Is there something that prevents this ?


texts: What animal classes has also "Like Humans" XY Chromosomes for Males and XX for Females?

texts:
Are other mammals. birds, reptiles, or even insects same to humans in that the male organisms have XY Chromoson at the end and female XX?

Thanks for the ansver


texts: Per Capita Population Growth Rate and Exponential Growth. Rate constants

texts:
As many of us might know, the set up of a differential equation relating instantaneous population growth with respect to time to the per capita population growth rate and current population size at an arbitrary time is as follows:

dN/dt = rN

Now, we are told that the constant, r, is the per capita population growth rate. N is the current size of the population at some time. "r" is the "organisms added per reproductive period" divided by the total population at that time. For instance, if 10 rabbits are born per month and the current population is 100 rabbits, then r = 0.1.

Let's consider a case where a population is doubling every reproductive period, modeled by 2^t. we can choose to model 2^t in base e and equivalently we have e^ln(2)t. So  2^t = e^ln(2)t = e^kt where e^kt is a general formula for exponential growth or decay. For doubling, k = ln(2).  In differential equation form we have dN/dt = kN , k = ln(2)

You can't get natural log of 2 by taking the number of organisms added to the population and dividing by the current total population. r does not equal k no matter how you set up your growth rate, but the structure of the relationship is the very same differential equation for exponential growth: dN/dt = kN, which we can integrate to a general form such as A*e^kt.  Why do we use this "r" contrivance at all? I am not sure I understand this choice. How is r different from the standard exponential growth factor k? What does it help us to understand in modeling the population growth rate?


texts: What evolutionary reason is there for hemolytic disease?

texts:
Nowawadays we have methods which allow us to overcome hemolytic disease of newborn or to prevent it to onset. The Rh or Kell conflict, but how is it possible that it is present? Why it haven't disappear due to natural selection?

A hemolytic disease occurs for example when mother have Rh- and the unborn child have Rh+ after his father. Then when the blood of the child gets to mother circulatory system she creates anti-Rh+ antybodies which will attack and eventually kill her next baby with Rh+. Thus we can assume that hemolytic disease is genetically dependent and cause lethal effect.

So i'm looking for any explanation. I know, that there can be none, i'm just asking.


texts: Microtiter Dish Biofilm Formation Assay- Pseudomonas and Crystal Violet

texts: If Pseudomonas is a gram negative bacteria, it does not retain crystal violet but why is it that so many people are using crystal violet staining in theri Microtiter Dish Biofilm Formation Assay?


texts:
I was watching a program about Barracuda - they have a front tooth that is supposed to be razor sharp.  My kitchen knife goes blunt if I use it for long periods without sharpening.  Sharks keep on growing new teeth but barracuda don't.

How do fish like Barracuda maintain a tooth that is razor sharp?

Edit News article on how sharp the tooth is

http://www.dailymail.co.uk/news/article-1348152/Barracuda-attack-breaks-womans-ribs-forces-boyfriend-seal-punctured-lung-hand.html


texts: How to find conserved residues across species?

texts: I want to identify if certain phosphorylation sites are conserved for protein X across humans and yeast. I know from MS data that there are 4 phosphorylation sites in Human protein X. In order to identify if these residues, and therefore potentially the phosphorylation sites, are conserved, is it correct to align both sequences using pairwise comparisons by using software like Needle? Or should I rather perform a bigger alignment and use clustal omega? Are there better approaches?


texts: Identification of store-bought succulent plant

texts:
I bought this succulent in the Bronx Botanical Garden Shop, but it was unlabeled. On the photo it is about 4" high:

Can anyone help identify this? Could this be Echeveria haagai? It's indoors in NYC.


texts: Firstly, Spider ID? Also possible relation to ~100+ serious bite reactions in past 1-2yrs

texts:
Might have been occuring since day 1 in new residence about 2 years ago. Bites are painful to touch, when fresh, very odd sort of void filled with black stuff under skin which regularly shows fang type trackmarks.(golf ball size swelling, pussing, twin &/or parallel punctures wounds, black(necrotic?) Substance under hardened skin cap as healing, long term healing) Spider found in nightstand drawer, maybe stranded in bottom of SS can cooler.
I have many pics of the live spider in a jar. Thankyou...;)>!


texts: The solution is A, but I think both A and C are correct. For choice C, stomata that protected by hairs will have a greater amount of water vapour around them, hence lower water potential gradient. Hence, this results in the reduction in the rate of transpiration, as well as choice A.


texts: enhancers in cell-type-specific signatures

texts:
I was reading an article in nature : Epigenomics: Roadmap for regulation and was confused by the definition or/and interpretation of enhancers.

  Enhancers are activated through interactions with transcription
  factors, which recognize and bind to specific DNA sequences within the
  enhancer region. Bound transcription factors recruit co-regulators,
  many of which deposit or remove modifications on histones. […]
  Enhancers that are active in cell-type-specific epigenomic signatures
  are typically highly enriched in DNA sequences to which
  lineage-determining and signal-dependent transcription factors bind.

As far as I know enhancers are the DNA sequences to which TFs bind, and then everything including co-activators complexes bind to basal TFs on the promoter.

I am confused by the last line:

  Enhancers that are active in cell-type-specific epigenomic signatures
  are typically highly enriched in DNA sequences to which
  lineage-determining and signal-dependent transcription factors bind.

They state, that in DNA sequences to which TFs bind the active enhancers are highly enriched. For me it sounds strange because the definition of enhancers says that these are the DNA sequences to which TFs bind. And of course enhancers are enriched there because otherwise they would not be called enhancers. As for me they are trying to say that active enhancers (by definition TFs bind to them) are highly enriched in enhancers region to which TFs bind.

Does it make sense or not?


texts: Pump to separate protein/DNA instead of electrophoresis?

texts: I know that DNA molecules or proteins can be separated in electrophoresis because the electrical charge is used to pull the DNA through the gel. So instead of using electrical, can I using physical impact like pumping ?


texts: At what saltiness will water simply pass through us?

texts: If water has a low salt content, it hydrates us. When water has too high salt concentration, like sea water, it drains water out of us instead when we drink it. At what salt concentration would water leave us completely unaffected?


texts: Do neurons that *don't* fire together unwire?

texts:
We all know the classic Hebbian theory, often phrased as "neurons that fire together wire together."  I'm curious about how other connections get pruned when two neurons start to fire together.
If two neurons start to make a strong connection and fire together often, will they prune connections to other neurons faster than if they were merely "dormant," becoming more and more selective towards that channel.  Or is the result simply a more connected structure and the pruning of connections continues to occur at the usual pace?


texts: computing relative synonymous codon usage from a coding sequence alignment while accounting for phylogenetic inertia?

texts: I would like to compute the relative synonymous codon usage (RSCU) from coding sequence alignments. But since the coding sequences from an alignment are not independent realization, the statistics (RSCU) need to account for the phylogenetics autocorrelation present in the data. How can I do that?


texts: Why does oxidative phosphorylation require complexes 2 and 3?

texts:
I am learning about oxidative phosphorylation in cellular respiration now and do not understand the roles of complexes 2 and 3 in the process. Specifically, my textbook says that 2 and 3 pump H+ out into the inter-membrane space, just like complex 1 does.

Complex 1 pumps out the H+ from NADH, and I suppose that 2 would be needed to pump out the H+ from FADH2, but then why do we need complex 3? All the H+ has been pumped out already--there's none left!

Also, if this understanding were correct, there would be no purpose for the chain that started with NADH to go through complex 2 at all (because it already went through 1, as opposed to the chain starting with FADH2).

Thanks in advance for any clarification you can give.


texts:
This should be pretty easy. We have a tropical fish tank, and among a few other species we have an adult pair of these guys. The female is a live-bearer, and seems to be giving birth to two young at a time. However, I can't for the life of me remember what kind of fish they are.

The male is in the foreground, and the female in the background. Any ideas?


texts:
Is there any stem cell or biogel method that exist for muscle and tendon lengthening?

It is known that height surgery is limit to six inches with two surgeries and three inches each, it is also true that there is limit because the muscle and tendons could stretch no more. Is there some research about this?


texts: Can low melatonin levels and/or LED lights cause or exacerbate macular degeneration?

texts:
I have two questions that may or may not be interconnected. My first question is:

Does melatonin prevent macular degeneration? Could low melatonin levels (caused by blue-rich light exposure in the evening and night and/or by insuffient sleep) heighten the risk for macular degeneration due to shorter amount of time that melatonin scavenges free radicals in the retina?

Evidence is conflicting as to whether exposure to sunlight contributes to the development of macular degeneration. A recent study on 446 subjects found it does not [1]. Other research, however, has shown high-energy visible light ("blue wavelengths") may contribute to age-related macular degeneration [2 and 3].
Data indicates that melatonin, being an efficient antioxidant with antinitridergic properties, has a promising role in the treatment and management of glaucoma. Melatonin could protect the ocular tissues against disorders like glaucoma, age-related macular degeneration, retinopathy of prematurity, photo-keratitis and cataracts [4].
However, melatonin secretion is inhibited by short or low quality sleep and by the ubiquitous blue-rich light exposure in the evening and night, hence for many people melatonin secretion starts as late as 90 minutes after falling asleep (i.e. 90 minutes after the last exposure to shorter visible spectrum wavelengths). As a consequence, melatonin has less time to function as an antioxidant in the body in general (which has been proved to result in higher cancer incidence) and also in the eye. When people are not exposed to blue wavelengths in the evening (e.g. by using firelight or dimmed incandescent bulbs or wearing red glasses) melatonin secretion starts roughly 90 minutes before sleep so melatonin has more time to do its antioxidant work.

My second question is about the relationship between macular degeneration and LED lights.

Could LED lights also increase the risk for macular degeneration?

Typically, LED lights (CCT = 4000 K) have a maximum peak at around 451 nm and a minimum in the 460-500 nm range (as is shown in their spectral power distribution of such LED lights below).

Melanopsin that controls pupilary reflex (pupil constriction), however, has maximum sensitivity around 479 nm - right in the LED spectral power distribution's (SPD) minimum. Could it be that due to this gap in SPD the pupil does not constrict enough and hence allows more of this blue rich light into the eye that as a result generates more free radicals and contributes to macular degeneration? Could this in combination with low sleep quality contribute to the onset of macular degeneration as LED (and lack of sleep) are widespread?
PS: I vaguely understood that at the moment it might be hard to answer some questions regarding melanopsin, but I am not sure how much it is related to my question. "It would be desirable to be able to quantify light as experienced by non-visual systems (melanopsin) using a single, one-dimensional unit (the equivalent of photopic lux). Achieving this for lights of divergent spectral content, however, awaits elucidation of a suitable spectral weighting function" [5]


texts:
I just read that pregnancy in space would be super dangerous because - among other reasons - of a higher risk of mutations due to radiation. This made me wonder: why does the DNA in organisms mutate? What are the main natural reasons? Is this due to the construction of DNA and would happen even in "perfect" conditions or is it due to something that is in the environment, like radiation?

So far I got two answers on reddit and also asked this question to a doctor and what I heard is along the lines of "this is how it is". I heard about "cells being worn out". But what makes the process non-deterministic, probabilistic? I guess I don't know enough about biochemistry to formulate the question, but I guess it's related to "given certain conditions, what determines at which point (and what kind of) a mutation occurs?"


texts: What is the protocol for extracting Protease Onion?

texts: I am Investigating the protease concentration in certain fruits and vegetables. I am unable to find the protocols for the extraction from onions. I want to purify my protein using the ammonium sulphate (salting out) followed by dialysis. I am specifically concerned about the mass of ammonium sulphate that is required and the amount of water I should dissolve it in.


texts:
I calculated an AMOVA from a genind object, with one hierarchical factor. In the table I obtain there are SSD values (for my grouping factor,"Error" and total) and sigma2 values (for my grouping factor and "Error")

I have two questions:

What does "error" stand for?
How do I calculate Fst? Which values do I have to use?


texts: Area under the curve in a drug concentration curve

texts:
I am not from a background on pharamacokinetics and trying to learn some concepts.

I noticed that the definition for AUC involve the first 24 hours. For example in here AUC is defined as "the area under the concentration–time curve over 24 h
divided by the MIC."

Is there any reason why this 24 hours is selected?
Say I test 2 treatment strategies. Strategy 1: 500 mg tablets given 3 times a day (500m g×3, 8 hours apart) and Strategy 2: 500 mg tablets given 3 times a day for 2 days (500 mg×6, 8 hours apart).
In this case if I simulate the change in the drug concentration over time assuming exponential decay, then the two concentration curves would have the same values for the first 24 hours. Therefore the AUC obtained in the first 24 hours for these two strategies are the same. But strategy 2 performs better than strategy 1. So, in this case isn't the total area under the curve above MIC a better index than consdiering AUC in the first 24 hours?
Is it wrong to inform why a particular dosing strategy is effective than the other one using 'Total area under the curve (rather than of the first 24 hours)'?


texts: By what physiological mechanism do we not feel microbes (bacteria, etc.) living on our skin?

texts:
Background
I know our bodies have a handful of ways to threshold our awareness of sensory stimuli:

Neural density

Sensory acuity
I assume really tiny stimuli could fit between receptors

e.g., Oaklander (2001) found nociceptor densities of 2-4000/mm2

Impacts summative abilities to surpass postsynaptic impulse thresholds

Varying thresholds of individual receptors.

Dubin & Patapoutian (2010), for example, show variations in classes of neurons based on their temperature (°C) and mechanical force (milli-newtons) thresholds (see thresholds listed in Tables 1 and 2).

Reticular formation involvement in regulating what we are consciously aware of

My question:

Which of the above physiological mechanism(s) are primarily responsible for our lack of sensation (or lack of conscious awareness) regarding microbes on our skin?

Update: My question is explicitly about physiology. Regardless of the impacts, benefits, evolution ,etc. of not feeling them, they're there. But even though we're covered in microbes, we don't sense them -- how not? I want to know by what physiological mechanism(s) we don't feel microbes on our skin.


texts:
I am not a biologist, so please bear with me for this basic question. Although I tried googling, I am confused.

What is the difference between plastids, chloroplasts and mitochondria?
Are there any plant sequence databases for each of them (plastid, chloroplast and mitochondria)?
Can we separate chloroplast, mitochondria, plastid sequences from whole genome assemblies?


texts:
I have a question about the novel coronavirus and swine flu.

How do the death rates compare between the two diseases?
How do the transmissions and rate of transmission compare?
Was a vaccine developed quicker for swine flu?

I ask because I don't recall this level of global disruption during the swine flu outbreak.


texts:
I recently had ants find and then swarm to a food container that I put down on a desk. I'm curious as to whether an ant would have needed to get lucky (i.e., discovering the food after crawling up the desk) or ants have the ability to sense food from a distance.

I'm skeptical of believing that ants simply scout around until finding food; I'll use this case as an example:

My room has had no food or drink in it for weeks, so the area wouldn't be a "hotspot" for ants to be interested in.
I put the mostly empty food container down on my clean desk and turned my lamp off to work on the computer. No more than 2 hours later did I turn my light back on to discover a trail of ants swarming to the container I put down. It happened pretty quickly.
The desk is high, standing on four thin legs. I find it difficult to believe that an ant would crawl up the desk as often as a 2 hour time frame to scout for food, for the message to be passed to the colony so quickly.

I've been curious about this scenario for a long time. So my question:

Can ants sense food from a long distance? If so, how does it work? If not, how is the phenomena (ants locating food quickly in unlikely places) explained?


texts: What are the mechanisms of disabling extrinsic control of heart?

texts:
I started this thread by thinking this question but I developed it further below

  What is the mechanism maintaining refractory period of pacemakers?

My conjecture is that the mechanism is the simultaneous depolarisation of at least SA node and AV node.
I am not convinced yet about the Purkinje fibers' participation.

Bigger question from this is:

How do pacemakers work under threshold without action potential?
There are continually leaking Funny channels (Na+) in pacemakers.
There has to be chemical changes intrinsic changes

change in the permeability of Funny channels or
active pumping of Na+ out OR pumping something negative inside the cell (probably Cl-, not sure) and

extrinsic changes

reflex arch blocking the action potential of pacemakers when enough preceeding sensitisation of AV node

I have no evidence for that this kind of sensitisation would happen in SA node or in Purkinje fibers.

which all seem to be working together in firing recovery mechanism through AV node without specific SA node stimulation.
Example logic tree for a myocardial infarction patient of 68 years old:

R wave of atrial fibrillation and flutter
extrinsic stimulus to start sensitisation of AV node
intrinsic sensitisation of AV node
extrinsic stimulus through reflex arch
systole and upper-systole of AV node starting
lower-systole of AV node

intersection of upper- and lower-systoles

unstable end of lower-systole
unstable systole
extrinsic firing simultaneous SA and AV node (similar extrinsic regulation as in the beginning of this logic tree)
prolonged and stable refractory period and long compensatory pause

  It is debated whether the pathophysiology of IST and POTS results from abnormal autonomic regulation or abnormal sinus node function.

My conjectures based on my logic tree

Pathophysiology of IST results from normal extrinsic (recovery) mechanism of autonomic regulation which body uses to recover from abnormal stimuli (etc atrial fibrillation and flutter)
Pathophysiology of POTS results from abnormal extrinsic mechanism of autonomic regulation when there is no stimuli after abnormal stimuli

What is causing the abnormal autonomic mechanism in POTS?
I would say that IST precedes POTS.
Prolonged IST seems to be going to POTS.
Physical explanation is that the body cannot last regular IST so it goes to POTS, since losing its normal extrinsic regulation.
What is this (apparently cumulative, not necessarily long-term) trigger of disabling the extrinsic autonomic regulation of the heart?


texts: In which way would the yeast cell cope with the excess amount of methionine in the growth media?

texts: I guess that when there is surplus of methionine in the cell it is incorporated in the TCA cycle as a succinyl CoA, with cysteine as a by-product. But now the cell has the surplus of cysteine. What does it do with it? How does it remove excess sulphur from the cell? Would that process somehow influence NAD+/NADH balance?


texts: Has the human 7-day week had any impact on the evolution of species?

texts:
Most (if not all) industrialized countries follow a 7-day work week now, such that we are bound to follow a certain weekly trend in matters such as pollution generation, where to go (e.g. stay in town during weekdays, more likely to go to parks during weekends), what to do (mow the lawn on weekends).

Is there any evidence of any species evolving to adapt to the pace of the human 7-day week lifestyle?


texts: How does chromosome number get halved in meiosis I?

texts: In meiosis 1, it is said that chromosome numbers become halved in the two daughter cells. For example, in a 2n human cell there are 46 chromosomes. During meiosis 1, the cell will undergo interphase and probably the S-phase, where chromosome number becomes duplicated. Now the cell is 4n (i.e. 92 chromosomes). During anaphase 1, 46 chromosome out of 92 would go towards one pole and 46 would go opposite. Thus the resulting two cells will have 46 chromosomes in each. So why should we say that, in meiosis 1, the chromosome number is reduced? I say that S phase shouldn't occur in meiosis 1 but rather it should occur in meiosis 2. Is my reasoning incorrect?


texts: How can potassium rich foods reduce blood pressure?

texts: How come sodium increases blood pressure, but potassium, which has to some extent similar properties helps lower it?


texts: Are microRNAs transcribed from the same DNA strand as their parent messenger RNAs?

texts:
I am new to micro RNAs. I have been trying to find the answer to the question if microRNAs are transcribed from the same DNA strand as the messenger RNAs encoded by the encompassing gene?

From the scientific articles I have read so far, I infer that it is the same strand. If so, does the transcription of microRNA and mRNA occur simultaneously?

Finally, does the strand from which the microRNA is transcribed have any implications for its interaction with its mRNA target?


texts: Differences between synaptic connections

texts:
Consider the following synaptic connections (from here):

axodendritic - A term pertaining to an excitatory or inhibitory synaptic connection between the presynaptic axon of a transmitting neuron and the postsynaptic dendrite(s) of a receiving neuron in a nerve impulse pathway; such connections can influence whether or not a graded potential will be generated on a postsynaptic dendrite.
axosomatic - A term pertaining to an excitatory or inhibitory synaptic connection between the presynaptic axon of a transmitting neuron and the postsynaptic cell body/soma of a receiving neuron in a nerve impulse pathway; such connections can influence whether or not an action potential will be generated in the postsynaptic axon trigger zone at the axon hillock.
axoaxonic - A term pertaining to an excitatory or inhibitory synaptic connection between the presynaptic axon of a transmitting neuron and the postsynaptic axon hillock or axon of a receiving neuron in a nerve impulse pathway; such connections can influence whether or not an action potential will be generated in the postsynaptic axon trigger zone at the axon hillock.

What exactly are the differences between the connections in terms of their influence on the neuron?
To my understanding:

axodendritic: influences a dendrite $\rightarrow$ hence influences the graded potential of the neuron
axosomatic: influences the graded potential of the neuron directly
axoaxonic: influences the axon only (independently of the neuron?)

Hence, to my understanding the axodendritic and axosomatic connections yield the same result: they influence the graded potential of the neuron (e.g. whether the neuron "fires"), where the axoaxonic connection only influences whether the axon fires. Is this correct?
If so, then what is the purpose of dendrites? If axons can connect to the cell body directly, then why would they need dendrites (apart from yielding a larger connection surface to the neuron)?
Note: I have read this answer, which partially explains the use of dendrites. However, it also states that the signal decay due to the synaptic location is compensated for by the local potential change. Therefore, IMO, the answer states that the main advantage of having dendrites is that inhibitory axosomatic synapses can capitalize on the location-dependence of the axodendritic synapses. Is that the true and only purpose of axosomatic synapses? (Please, correct me if my inference is wrong!)


texts:
Would I be correct in saying that the Bohr effect is ONLY related to the concentration of [H+] in the tissues.

Obviously the concentration of carbon-dioxide can contribute to this concentration by producing protons (through carbonic anhydrase) but it isn't directly involved in the effect?


texts: How to prove that pork meat has parasites

texts:
I suspect that the pork sold at a certain shop is infected with the parasite pork tapeworm (Taenia solium).

Is there a way I can prove this without special equipment? Would it work to leave the raw meat in the fridge (at 4 degrees Celcius, or higher?) for a week or so and the worms will come out of their eggs and grow big enough for the eye?


texts: What bird species is this? (Heron-like waterfowl from China)

texts:
I need help identifying this bird.  (Some sort of heron?)

It was seen in Wuhan, Hubei, China, in September.

It is very common there.  It can also swim like a duck, but I've only seen it do this once (it's not something they commonly do).  I can supply more photos upon request.

These are two different individuals:


texts:
Many of these little snails suddenly appeared in our aquarium from nowhere.  I suspect that some snail eggs hitched a ride with some recently purchased plants.

Can anyone identify the species?  I am not having any luck with googling.

The photos show a baby snail of about 2-3 mm in size.  The shell is asymmetric, with one side looking completely flat (or concave).

These  are not pond snails.  We also have (uninvited) pond snails, but pond snails look different even when as small as these.  This new species has a lighter colour than pond snails, a more transparent shell of a different shape, and moves slower.


texts: Enzyme immobilization: Factors that help or hurt success

texts:
Are there any factors to consider that can help / hurt the chance to get a successful immobilized enzyme catalyst?

i.e. The relative attractiveness of a live host synthesis vs an immobilized enzyme.

Specifically, the product of interest is a secondary metabolite of MW approx. & the host of choice is S. Cervesae. The transformation is a single step, catalyzed by a single, known enzyme with the gene coding for it approx. 2000 base pairs.


texts:
In the recent veritasium video about mosquitoes , the host says that the researchers used identical female twins and fraternal female twins to understand the effect of genes on attractiveness to mosquitoes.
Is there a scientific reason to use only female test subjects for the experiment?

The video:
https://youtu.be/38gVZgE39K8


texts: Human body power consumption in still state

texts:
I'd like to know what kind of power human body needs to maintain life, in still state (average daily power consumption of an average man is also of interest). In terms of watts.

I've only managed to find one figure - 1700 kcal per day without physical activity. That converts to 80 watts, which seems (intuitively) a bit low, so I wonder if it's the right figure or not.


texts: is it possible that there is no gene at a locus?

texts: "the location of a certain gene on a chromosome " is the definition I know for locus. ı just read that a gene is not necessarily present on a locus. how would that be possible?


texts: Recommendations for textbooks on statistical and quantitative genetics, and genetic epidemiology

texts:
I'm looking for a textbook on statistical genetics, quantitative genetics, association mapping, and genetic epidemiology. My interests include, but are not limited to, complex trait analysis, and the mathematical and statistical aspects of these subjects.

I've found a lot of books, below are some that I'm considering:

"Genetics and Analysis of Quantitative Traits" by M. Lynch et al. (amazon link)
"Introduction to Quantitative Genetics" by D. Falconer et al. (amazon link)
"Statistical Genetics: Gene Mapping Through Linkage and Association" by B. Neale et al. (amazon link)
"Statistical Genetics of Quantitative Traits: Linkage, Maps and QTL" by R. Wu et al. (amazon link)

I haven't found anyone else posting this question. There are discussions about population genetics textbooks, but these books have limited information about quantitative genetics, etc.

If anyone has a favorite book, comments about the books above, or anything, I would greatly appreciate it.

Thanks in advance.

EDIT:

Another promising book:

"The Statistics of Gene Mapping" by D. O Siegmund (amazon link)


texts:
What is the function of the membrane potential? Cells invest huge amounts of ATP to drive ion pumps to sustain this potential. Therefore it must have a very important function.

I read somewhere that the membrane potential acts as a battery, which can be used to energize other processes. But probably most of these processes could be energized with ATP just as well, which could be used directly instead of wasting it into building a potential first.

In muscle cells and nerve cells changes in the membrane potential are used to transmit information, so that is one use for it. But what about all the other cells?


texts:
I'm interested in designing an ELISA to detect the presence of Aflatoxin B1, but I'm having a hard time finding information about designing an enzyme and some sort of guidance on how ELISA protocols are designed, and generally where I can get more information. I'm in Grade 9 and am extremely unexperienced to a lot of the terms I'm coming across, but I'm very interested and would be grateful if anyone has a book or a website I can visit to get started or give me some sort of direction.

Thanks,
Joshua


texts: How do parents give their offspring a chromosome?

texts:
Whenever an organism sexually reproduces, it gives its offspring one chromosome from each of its pairs of chromosomes. My questions are

Is this done randomly?
Is it uniformly random?
If so, what mechanism allows it to be random, considering that the laws of physics are deterministic?

(Note: I'm a little rusty on this subject, so if there are any errors in the question, feel free to correct them.)


texts: Abbreviations for molecules: What are CheW, CheA, CheY?

texts:
I've encountered the abbreviations such as "CheW" and "CheA" for certain organic molecules.  For example:

  Proteins associating with the Tar complex include the autophosphorylating protein kinase CheA, the transducing protein CheW, the methylating enzyme CheR
  and perhaps the protein phosphatase CheZ.  (Morton-Firth et al. 1999, p. 1060; available here)

What does "Che" stand for?  What do the capital letters at the ends of the abbreviations mean?

Let me know if this would be a better question for chemistry.SE.


texts: Comparing angles between population vectors of neural activity

texts:
I am reading this paper on fear conditioning, where the following is given:

The n-dimensional population vector (activity of n neurons) evoked by the conditioned stimulus (CS+, auditory tone) before conditioning
The n-dimensional population vector (activity of n neurons) for the CS+ after conditioning

The authors write that: "[After conditioning] the CS+ population vector rotated out of the plane defined by the US [unconditioned stimulus] and the initial CS+". They conclude that this out-of-plane rotation corresponds to "new learning".
My question: Why is out-of-plane-rotation of neural activity vectors equated with a new representation/new learning?


texts:
When the shoot apical meristem is cut out/removed, it induces lateral growth. I'm wondering if this means that that stem will never grow vertically again. Is there a way to stop lateral growth after the apical meristem is removed? Is there a way to grow that meristem back again?

Thank you


texts: How are drug metabolism and detection related?

texts:
If someone is taking treatment for a psychiatric disorder (e.g. diazepine), then would traces of the metabolized drug be detectable in their sweat or saliva?

Any links to resources regarding this, or any help is greatly appreciated!


texts: Flow diversion for cerebral aneurysms or stabilizing the hemodynamics?

texts: I'm doing research of flow diverter for cerebral aneurysms applications and I'm wondering the reason behind stent placement underneath of cerebral aneurysms is to divert the flow or stabilize the hemodynamics (e.g. reduce wall shear stress or blood flow velocity in the aneurysmal region)? Let's say people do it to divert the flow and prevent blood to enter the aneurysmal region. That looks fine for side wall aneurysms when there is no smaller arterioles or branches connected to the aneurysm, but for terminal aneurysm where the flow diverter may block the blood flow into smaller arterioles, is it a appropriate case to deploy stent? I mean if we prevent the blood to enter some part of smaller arterioles how brain could maintain its functionality due to its need for oxygen. I appreciate if someone could explain the logic behind the flow diverter placement in the cerebral aneurysms.


texts: Tools for modelling and visualizing growth of cells

texts:
I am looking for a program/GUI app/package that would help me do simulations for cell growth. I have a microscopic mathematical model, and the scenario is basically the following: I start with a rod-shaped cell characterized my its center and direction angle, it grows until it reaches a certain length, it divides into two identical cells whose angles change randomly and the process continues.

Is there any program or package that I can use for such a situation? I have found several on GitHub, but they were mostly for very complicated biological processes. I use Python/Julia/Matlab and can code, but I was wondering whether there are any tools for such simpler scenarios.


texts:
I am studying by myself Human Physiology.
I have encountered the following question:

In the following given model of sodium channel with 3 states open closed blocked (which I assume means inactivated), the rates of going from state to stated are given in the picture below.

a. Write matrix $Q$ for the system and find it's eigenvalues.
b. What does these values represent?

If anyone has an idea what is the required matrix I will be grateful.
Thanks!


texts: Which animal dug this 5 cm diameter hole deep into mud and build a large mound around it?

texts:
I noticed the large structure below today at the edge of a very small pond in northern Taiwan lowlands. It is June and it has rained a bit the past few days, and this 15 cm mud dome with a 5 cm diameter hole going straight down looked fresh and wet and glistening.

It is hard to tell for sure but it looks like the borough went deep enough to reach the water line of the pond next to it, but I could not tell because it's dark inside and I did not have a flashlight.

The mound is large, perhaps 15 cm tall and wide, which suggests that a lot of material has been removed and the tunnel could be quite deep.

The pond is only about 3 x 5 meters in diameter.

Question: Snake? Crab? Mole? What further information can I collect about it that would help to identify what produced this?

click images for full size view


texts:
I am using the following protocol to extract chromosomal DNA from bananas:

Cut up one banana into small pieces, approximately (1 cm3)
Add ½ a cup of warm salt water and the banana pieces into the blender and set to max for 5-10 seconds
Poor into a beaker and add 1 teaspoon of detergent to the beaker
Stir for 5 mins with a spoon to break down the plasma membrane
Place the mixture into a centrifuge for 30 seconds
Pour the mixture through a gauze with a beaker catching the liquid underneath
Smoothly pour cold ethanol into the mixture at a 1:1 ratio so a clear layer of liquid will form on top of your mixture

Why is the centrifuge step (5) needed? Why would that increase the yield of DNA?


texts: Criticism of the significance of fMRI studies

texts:
On the german Wikipedia page on fMRI I read the following

  "There is some critisism of the basic assumptions and possible
  insights gained from fMRI studies which is based on a constructive
  component of the visualization of measured data, whereby it is more
  the ideas and expectations of the researchers than the actual
  processes that are visualized." (translation by me)

Can these "basic assumptions" and "expectations" be made more precise, and the way how they are reflected in the "constructive component", and how the constructive component in turn is reflected in the visualization (which doesn't necessarily show the averaged but true activities of neurons)?

Especially:

What do typical "basic assumptions" concern? The processing of single neurons, the inner connectivity and processing of groups of neurons, the collective processing of different groups of neurons, the interwovenness of neurons and blood vessels?
What is a specific typical "basic assumption" in the context of fMRI?
What is a typical "expectation of the researcher"? Finding a correlation between two regions of activity while performing a task?
What is a typical "constructive component"? A method of statistical analysis? Or something else?
How does an inappropriate "constructive component" typically lead to false fMRI visualizations?
Do fMRI researchers regularly check if a BOLD signal really (or most probably) reflects neuronal acitivity at that spot - and don't display it if not?


texts: Which white beans have phosphatidylserine?

texts:
Many articles online say that plant foods are poor sources of phosphatidylserine, except for white beans, which have 107 mg per 100 g.¹ ² ⁴ Honestly though, I think they might just be repeating a claim from Wikipedia, which cites "Souci SW, Fachmann E, Kraut H (2008). Food Composition and Nutrition Tables. Medpharm Scientific Publishers Stuttgart." I wasn't able to find this source freely available online. Examine.com mentions that "Phosphatidylserine (PS) is found in Soy Lecithin at around 3% of total phospholipids"⁵, citing https://www.ncbi.nlm.nih.gov/pubmed/18846580.

I haven't been able to find any (reliable) sources that say which kind of white bean is being referred to here: is it navy beans, cannellini beans, great northern beans, runner beans, or marrow beans? There are some that say navy beans,³, but I believe that information is derived from the Wikipedia article on phosphatidylserine, plus some speculation based on what the writer of the article thinks "white bean" refers to.


texts: How would a different solar day affect evolution?

texts:
Has anyone theorized how evolution would be affected by a different length of solar day, what were the conclusions?

The thought came from thinking about life on other planets/moons, but I'm initially thinking about it from the frame of "How would life on earth and humans specifically have evolved (or if they would have) if a day were 12 hours or 48 hours?

I imagine the actual effects on evolution and lifestyle would be extensive.

Note: this question How would the human body adjust to sleep times if we were to live in a place with different day lengths? is slightly related, but just to clarify I'm intersted in effect on evolution, not adaptation if an indivdual moved between planets.


texts: natural characteristics of insects used as human disease model

texts:
In this paper [1], the author found that the autism-related genes are conserved between honey bee and human. Thus, this paper providing a means to further explore sociobiology theory. In my opinion, the honey bee have the potential to be developed into an model for human autism disease.

My question is: what other examples in insect like this in honey bee that the model species itself has some characteristics, which could be used as model system for some human disease studies?

Thank you!

[1] Shpigler HY, Saul MC, Corona F, Block L, Cash Ahmed A, Zhao SD, Robinson GE: Deep evolutionary conservation of autism-related genes. Proc Natl Acad Sci U S A 2017.


texts: Are Asians more genetically homogenous than other races?

texts:
I've heard that Asians (I'm not entirely sure which subgroup was being referred to) tend to be more genetically homogenous than other races, with people of African lineage being on the other end of the spectrum being the least homogenous.

Is there any truth in the claim that Asians or a specific subcategory such as South East Asians have less genetic variance than other races?

I've seen papers like Extreme mtDNA homogeneity in continental Asian populations for example, but I don't understand enough to know if that answers my question.

If Asians have less genetic variance, would that lead to less variance in phenotypes?


texts: What makes animal to continually reproduce?

texts:
I was reading about Trypophobia and reached to Surinam Toad's reproduction methods. Then I had this doubt-
Why would animals want to reproduce so much?
In case of humans we mostly have the offsprings nearby for entire life, so some of them may take care of us. But in case of many other animals after birth they have no connection with their parents.

So why do they always try to reproduce in large quantities in entire life time?
What they achieve in this?


texts: What is meant by "the degree to which a gene is expressed" in an individual?

texts:
Here is an excerpt from a text that I was reading,

  Here is an example of microarray data. The idea is to take a group of
  different individuals and for each of them, you measure how much they
  do or do not express a certain gene. Technically, you measure how much
  certain genes are expressed. The colors in the graph, like red, green,
  grey etc. show the degree to which different individuals do or do not
  have a specific gene.

The data they are talking about is this:

But a gene is either expressed or not expressed right? It's one allele is expressed or another allele is expressed, or yet another one is expressed. It is a discrete thing.

Then what is meant by the extent or the degree to which the gene is expressed? Can a gene be expressed more in certain individuals and less in others? Please explain with example.


texts: What is the literal meaning of the scientific name for the cactus wren?

texts: What does the scientific name Campylorhynchus brunneicapillum mean? I simply want to find a way to decipher the meaning of scientific names. In the past I had to translate the names syllable by syllable using an abbreviated Latin dictionary to get a rough idea of the meaning. I can not find an on-line Latin translator that works - and not all scientific names are Latin.


texts: Are releasing-hormones and release-inhibiting hormones from the hypothalamus ever present in the blood?

texts: Our teacher said that these two hormones are normally never present in the blood stream, and to be carfeul of it if it comes as a question. I'm not conviced to be honest, is this true?


texts: Can human eys/the brain be trained to see with bidirectional monocular vision?

texts:
Most people have a dominant eye, and while it uses its non-dominant eye in tandem with the dominant eye most of the time, the brain, being an expert in eliminating redunant information, ignores the images received from the non-dominant eye.  However, with special training or practice most individuals can force the brain to temporarily switch to receiving images from their non-dominant eye, even to receive images from both at once, resulting in a blurred chamelion-like or image.

Some individuals however, have a non-dominant eye so weak, that not only does the brain ignore the images it sends, the eye it self no longer moves in tandem with the dominant eye.  This is known as strabismus or Lazy eye.

My question is, if the eyes are capable of not moving in tandem in those people, why can't we all train our eyes to move independently, and couldn't we also train our eyes to focus on two different images (on opposite sides) at once?