texts: Can two populations of the same species pollinate during different times?

texts:
My question comes from the Barron's SAT Subject Test Practice Test #1 question 2
It states:

Two populations of rhododendron, R. ferrugineum, grow in the same region of Connecticut. Although rhododendrons are able to cross-pollinate, these two population never hybridize. Which of the following is the most likely reason for this phenomenon?
A) Genetic drift has caused one populatoin to be betteer adapted than the other.
B) Self pollination is more advantageous because it increases variation in the gene pool.
C) One population produces pollen in early June when the pistils of the other population are not ready to receive pollen.
D)The two populations demonstrate convergence of two separate species over time.
E) The two populations fill different niches

The Barron's book says that the correct answer is C. Why? If the it's the same species, shouldn't they produce pollen at the same time?


texts:
I was given the plant as a gift.  Started out small and has grown to almost 6 1/2 feet tall and has sprouted off spring.

Original

Offspring:

Google reverse image search resulted in "Houseplant".  Not very helpful.

I have since removed the dead leaves from the plant.


texts: Is there a correlation between B12 deficiency and cardiovascular disease?

texts:
I've read in several health sites that state that high blood homocysteine, as well as low B12 intake, is not only correlated, but actually causes cardiovascular diseases. In order to verify those claims, I've looked for related studies and found controversial results. This one, for example, observed no positive effects from B12 supplementation:

  In this randomized double-blind trial, high-dose vitamin therapy had no effect on the outcome measures of stroke, CHD events, or death.

The author speculates several possibilities for the negative results, including that high homocysteine levels could be merely correlated, but not actually causing the problem.

I wonder if there have been advancements on that matter. Is it known whether low B12 causes cardiovascular diseases, or is merely correlated? If it is just a correlation, then what is causing both low B12, high homocysteine and increased cardiovascular disease? In particular, have any study observed if a diet rich in red meat, for example, has the positive effects that pure supplementation failed to show?


texts:
I attended a meeting where the speaker claimed that a human body reacts to the exposition to gamma rays reducing the amount of acetylcholine. Is this thing scientifically proven? I cannot find any source that confirm this thesis.

- Update -
The source from which the speaker based his theory is this paper. Excluding the fact that here gamma rays seem not to be mentioned, is this a reliable source?


texts: How were genes located before the development of bioinformatics?

texts: I would like to know the detailed procedure of how scientists in earlier time were able to locate genes like how we were able to locate Huntington gene in 1983?


texts: What color was the most recent common ancestor of all swans?

texts: Was the most recent common ancestor of all swans black, or white, or some other color? How do we know, and how certain can we be?


texts: What kind of spider is this? SE Michigan, light brown color, second picture less focused but w tape measure for scale. Thank you!


texts: Which hydrophobicity scales are best for detecting transmembrane regions, and why?

texts:
There are many hydrophobicity scales for protein analysis.

Broadly, I gather the differences between them are from the experimental method to acquire the data and the normalisation (or lack thereof) of the data.

To detect/predict transmembrane segments one method is to use a window of 19-20 of these residue scales to detect a region of hydrophobicity above a threshold. The Eisenberg et al. scale is used by uniprot for example.

Uniprot don't seem to explain their choice of using the Eisenberg et al. scale.

Why might one use a certain scale over another when predicting transmembrane segments?


texts: Clarification on RefSeq Genes track on IGV

texts:
The following picture is a snapshot of the RefSeq Genes track (collapsed) on IGV. I know that the bold blue line indicates exons and the thin one indicates introns.

However, I cannot find what the medium line stands for. Is it part of the exon? Why is it different?

I have checked into the manual but I couldn't find any relevant info.

When you expand the track (bottom picture) even more diverse lines appear.

medium blue line without arrows
medium line with arrows
bold line with arrows

Can anyone explain to me what is the difference between all of them?


texts:
Can someone please tell me what is Degenerate alignment analysis? Could not find a good article on the internet that could help me understand what it means?
(I have not studied biology since last 8 years and now I am going through it because I need it for my research. So if someone can describe it in simple language it would be very helpful)


texts: Why do retroviruses go through a DNA stage to replicate their RNA genome?

texts: Why do retroviruses (e.g.HIV) convert their RNA genome to DNA (using reverse transcriptase) and then transcribe it back into viral RNA (and translate that into viral proteins). Surely to replicate their genome it would be simpler to use RNA-dependent RNA polymerases as RNA viruses like Measles Virus do.


texts: What species is this ? It is a stinky, hairy plant. I have found it nearby a river. It had reached a height of 1 meter. Bloomed three weeks ago. Found in Turkey.


texts: Does anyone know what this is? It is seen in France. It looks like it has eight legs and is about 8-10 cm long.


texts: Interpretation of F in inbreeding on the population level

texts:
The inbreeding coefficient for an individual gives the probability that the individual has two alleles at a locus that are IBD. What interpretation does the inbreeding coefficient have on the population level? Is it the average inbreeding value in the population?

It is possible to derive the genotype frequencies in the population when the population inbreeding coeeficient is given by F. These are given by:

$A_1A_1$: $p_{A_1}F+p_{A_1}^2(1-F)$

$A_1A_2$: $2p_{A_1}p(1-F)$

$A_2A_2$:  $p_{A_2}F+p_{A_2}^2(1-F)$

Is seems like F gives the probability that the two alleles in an individual in the population are IBD. Does this mean that F is the average inbreeding coefficient in the population?


texts: Do mosquitoes need to pump blood out of the host?

texts:
Many species of mosquitoes have bloodsucking females.

When they bite a host, do they need to pump? Or does the sheer blood pressure combined with capillary action suffice to make the blood rush into the mosquito's stomach?
If the blood pressure is enough, can the mosquito "explode" or simply die from having too much blood rushing in?


texts: Can chitosan affect the absorption of unsaturated fatty acid?

texts: I know chitosan will decrease the absorption of fat. However unsaturated fatty acid, such as DHA, is beneficial. Does chitosan effect the absorption of unsaturated fatty acid?


texts:
I am looking for a book that covers the following topics in ethology:

Behaviour

Sensory filtering, reponsive-ness, sign stimuli, learning and memory, instinct, habituation, conditioning, imprinting.

Role of hormones in drive

role of pheromones in alarm spreading; crypsis, predator detection, predator tactics, social hierarchies in primates, social organization in insects.

Navigation and Biological Rythms

Orientation, navigation, homing, biological rhythms, biological clock, tidal, seasonal and circadian rhythms.

Methodology

Methods for studying animal behaviour including sexual conflict, selfishness, kinship and altruism.

Do you have any suggestions?


texts: I read something like "some tested variants show self-immunoreactivity". So, what exacly is self-immunoreactivity? Is it something like antibodies induced by a specific variant showing immunoreactivity to this specific variant?


texts: Is oxidative phosphorylation less efficient in gram positive bacteria?

texts:
Gram negative bacteria perform oxidative phosphorylation in their periplasmic regions, between the inner and outer membrane where a proton gradient is maintained and used by the ATP synthase to make ATP.

Gram positive bacteria do not have a second membrane, but only a porous polysaccharide capsule.  Oxidative phosphorylation then would on try to pump protons to the outside of the bacterium and it could diffuse out into the surrounding environment.  Does this cause gram positive bacteria to operate less efficiency?  does it make them more vulnerable to a basic pH in their environment?


texts: What is the relationship between migraines and histamine?

texts:
A family member suffers from migraines so I have been reading a little around the subject.

There seem to be any number of "triggers", but I have seen mention several times of the role of histamine in migraine activation as an active area of research. The suggestion is that high histamine levels in the body can cause migraines.

Is there solid evidence that histamine can trigger migraines?  How does this mechanism operate?


texts:
Recently I watched a Youtube Video by
Veritasium

He said we are actually feeling the rate of heat transfer, not the temperature.

But how do we feel temperature?
How is feeling temperature different from feeling heat and heat transfer?


texts:
This came up in my biology diversity course and I wanted to raise a question about it.

On the topic of ex situ, one of the presentations that a speaker mentioned that one of its disadvantages is that 'endangered habitats may be fragmented and each small area may not be large enough to ensure survival'. Unfortunately, she left before I could ask anything of this statement.

Can anyone clarify what this means?


texts: My school is very fortunate to have a DNA sequencer, and I want to find an opportunity to learn how to use it. I'm currently taking AP Biology this year, and I hope to do an independent study in biology next year, concerning DNA. I'm sure there's plenty I can do with the sequencer, but do you have any cool project ideas?


texts:
Is HLA matching/ blood grouping required for corneal transplants ? I think,it shouldn't be, because cornea is avascular.

I tried searching on the net but most of the references are old and controversial. So please provide a reliable and latest reference for your answer.


texts: What are Codominant vs Dominant Genetic Markers?

texts:
When talking about types of genetic markers, the adjective "dominant" and "codominant" are often used. I don't fully understand their definitions and found contradicting definitions.

Foll and Gagiotti (2008)

Typically reading from  Foll and Gagiotti (2008), they list give two examples of markers of each type

Codominant markers

SNP
microsatellite

Dominant markers

RFLP
AFLP

reddit

This reddit post indicates that RFLP are codominant markers (unlike stated in  Foll and Gagiotti (2008)).

wageningenur

On wageningenur.nl (random website I never heard of before), they define dominant and codominant markers based on gene expression suggesting that the terms dominant and codominant used for markers have the same definition than those used for allelic effects on the phenotype (dominance, recessivity, overdominance, etc..).

Questions

What are the definitions of dominant and co-dominant genetic markers?
Can you please offer examples for each type and explain why they fit in one or another category?
Do the terms dominant and codominant have the same definition when used to describe a marker and when used to describe allelic effects on the phenotype (dominance, recessivity, overdominance, etc..)?


texts: Human genetic diversity in Africa in comparison with the rest of the world

texts:
Background

The claim ...

  Most of the genetic diversity in humans is in Africa

... is quite common. On Biology.SE, it is easy to find posts that make this claim. Consider for example:

Do humans have enough biological differences to be grouped into races or subspecies?
How do we know the human species arose in Africa?
What is the correct classification of population groups of homo sapiens?

Question

Is the claim true?
What fraction of the total genetic diversity is present in Africa?

I understand that the term genetic diversity is often used in a vague sense. Please make sure to explain what statistics has been considered in the study you would refer to when giving estimates of what fraction of the genetic diversity is found in Africa. Note that I am not asking "why is it true?" but only "is it true"?


texts: Can brain damage caused by physical injury affect the social behaviour of a person?

texts: Can a physical injury to the brain, resulting from an accident, and not the result of a diagnosed mental illness, affect a person's social behavior?


texts: What is the life-span of the various organs in the human body?

texts:
It is possible for a person to donate the harvestable organs (kidneys, eyes, and such) posthumously. Let's assume for a moment that the technology exists to kill rejection, and maintain the organ in excellent shape after it is harvested.

Could the organ/s ( e.g. Eye ) (assuming a decent life-style) travel for centuries from one donor to yet another donee? What is the typical life-span of the various organs in the human body assuming a healthy, and low stress life?

p.s. It's a curiosity question; my eyes even millenia after my death would continue to see.


texts: Rate of Diffusion Through Cellulose Membrane

texts: From what I understand, the larger the molecular size, the slower the rate of diffusion and vice versa. However, after doing a lab (similar to this one) about diffusion through a cellulose membrane, my instructor said that despite substances having different molecular sizes, the rate of diffusion (thru the membrane) will be the same. Could someone further explain or did I hear incorrectly?


texts: Is it possible to transfer acquired hemophilia with breast milk?

texts:
There is a transplacental form of acquired hemophilia: http://www.jpeds.com/article/S0022-3476%2895%2970132-X/abstract

This disease is caused by polyclonal immunoglobulins (IgG1 and IgG4) against the A2 and C2 domains of factor 8. So acquired hemophilia is an autoimmune disease. By the transplacental form the maternal IgG antibodies causing this disease in the newborn. As far as I know IgG antibodies are transferred with breast milk too. Can breast milk cause this disease?


texts: Is bad tasting food more likely to cause harm?

texts:
Taste is often referred to as subjective. For example certain foods taste bad to me, such as oranges, grapefruit, grapes, raisins, and sweet potatoes. However the wiki article on taste explains that from an evolutionary perspective, it's important that bad taste might indicate poison in the food; taste isn't an arbitrary matter of subjectivity.

With that in mind I pose the question if a food tastes bad to a particular person, is it more likely to be causing harm to that person than someone who finds the food pleasant? In other words, is the bad taste a sign that my body is not suited for some components in the food?


texts: What makes a metal safe to use for an artificial joint?

texts: What determines if a metal is suitable for transplantation such as in the hip? What I am most interested in however is why might some metals be toxic to animals once in the body?


texts: Why is Cysteine and Tyrosine used to calculate a sequence isoelectric point?

texts: Why are the amino acids - cysteine and tyrosine used in isoelectric point calculations for a protein sequence, yet neither of them are positively charged molecules? and are not used in net charge calculations.


texts: Using Canonical Correspondence Analysis on matrices with missing data

texts: I have a matrix of sites where not all the environmental variables I want to assess were sampled. In other words, there are sites with the whole set of variables sampled, and there are other sites where just some variables were sampled. Does Canonical Correspondence Analysis work with missing data for the environmental variables? If it does, what would be the effect of not including the missing values?


texts: Maximum loading volume for agarose gel with 10 well comb

texts:
I want to load my agarose gel with my PCR products, which are 50 µL reactions.

I am wondering how much of those reaction I can load into one well if I use a standard agarose mini gel (10 well comb, ~8 mm thickness, 1.2%).

Should I try loading the entire 50 µL into one well or should I split it into two?

Thanks in advance

Phil


texts: Use of pigs for obtaining transplant organs

texts: It is being said that organs can be obtained for transplant from the pigs. What is special about pigs that we are using them? Why can't we use monkeys or chimpanzees with whom we share a more recent common ancestor?


texts: Determining water movement in Cells with Same DPD

texts:
A cell has OP=10bars and TP =5bars .other cell has OP =15 bars and TP =10bars. DPD of both is same ie.5bars. So how do we determine in which direction water will move?

OP is osmotic pressure. TP is turgor pressure. DPD is Dossusion Pressure Deficient.


texts: Cross species effects of Apis mellifera queen pheromones

texts: I am looking for studies that show effects of Apis mellifera queen pheromones on other species. An example of one such study is where A. mellifera queen pheromones deactivated the ovaries of Drosophila melanogaster females. Similarly queen pheromone from Apis mellifera scutellate can deactivate worker ovaries in a different sub- species, Apis mellifera capensis (however, this is a sub species effect and not cross species). If anyone else knows any other studies of cross species effects, it would be highly appreciated if it could be pointed out.


texts:
Do oysters feel pain when you bite into the inside, or when you crack open the shell? I tried google searching it to no avail. When you bite inside the oyster or when you break the shell to open the oyster, does it feel pain?

EDIT: (Since some people think that mine is a duplicate) I'm asking if the oysters feel pain when we eat the inside, or when we crack open their shell. To the least of my knowledge, ants and oysters have a different body so I don't know if they do feel pain.


texts: Population dynamics ODE with Allee Effects

texts:
From reading about Allee effects, it appears that there is a modification of the one-dimensional logistic equation to account for an allee effect given by:

$$\frac{dN(t)}{dt} = rN\left(1-\frac{N}{K} \right)\left(\frac{N}{A}-1\right)$$

Here, $r$ is the species growth rate, $K$ is the carrying capacity, and $A$ is the threshold for the population to not go extinct $(0<A<K)$.

A few questions about this model:

1) What is it in this equation that determines whether or not the allee effect is strong or weak? It seems like the parameter $A$ would determine where the threshold is but not whether or not the effect is strong/weak.

2) I'm interested in an extension to a system of $n$ interacting species. Suppose I have $n$ competing species where each one is subjected to its own allee effect. Is this a suitable modification of the above ODE for $n$ species?

$$\frac{dN_i(t)}{dt} = r_iN_i\left(1-\frac{\sum_{j=1}^n\alpha_{ij}N_j}{K_i} \right)\left(\frac{N_i}{A_i}-1\right)$$

where $1 \leq i \leq n$. In that regard, the first two terms are the usual Competitive Lotka-Volterra model, and the last term accounts for the Allee effect.


texts:
I have been doing a lot of reading on quantitative genetics and the G- (and B-) matrix lately. I get the principle behind performing the analysis now but I am still not sure how to do it. I'd like to be able to try it out with some dummy/old data in R to see how it is done.

Let's pretend I have measured 5 traits of Drosophila (Wing length, lifespan, eye pigmentation, bristle number, and fitness). Could I construct a G-matrix for the population from this data and also get a B-matrix to measure the selection on the traits?

Aims of the post:

1) What information (trait measurements, fitness scores etc.) is needed to construct G- and B- matrices?

2) I would like to find print or online material that would guide me in actually implementing this method. It seems like there is an awful lot of papers saying that G-matrices are great, but no one actually says how to do them in real life...


texts: Why do 6-8% of diphtheria patients do not develop natural immunity after being affected?

texts:
I am thinking of why some patients do not have natural immunity after exposure to the A-B toxin of diphthria.
I think the A-B exotoxin is the key factor causing this disease and should trigger memory cells to form.

DT has both local and systemic effects.
Locally, its action on epithelial cells leads to necrosis and inflammation, forming a pseudomembrane composed of a coagulum of fibrin, leukocytes and cellular debris.
Absorption and circulation of DT allow binding throughout the body.
Local effects produce pseudomembrane.

The major impact of transduction in pathogens is the introduction and stable inheritance of virulence genes such as those coding for toxins.
C diphtheriae is lysogenic with a phage containing the diphtheria toxin gene.
Diphtheria toxin is produced by C diphtheriae only when infected with a bacteriophage that integrates the toxin-encoding genetic elements into the bacteria

The toxicity for intact cells depends on toxin binding and uptake.
In other words, the net effect of the toxin depends on the function of the target protein and the function of the cell.
B subunit binds to receptors that regulate cell growth and differentiation, thus exploiting a normal cell function.
A subunit inhibits protein synthesis.
B subunit binding determines cell susceptibility.
Absorption and circulation of DT allow binding throughout the body.
I think this uptake does not occur sufficiently with patients without natural immunity stimulation.

I think the reason for no natural immunity for some patients after toxin exposure is that the host does not stimulate enough adaptive immunity and no memory cells are built.
Again, this is because the bacteria has little invasive capacity.
Diphtheria is due to the local and systemic effects of DT with potent cytotoxic features.
The uptake of the toxin varies also among some patients.
So other patients have probably more local effects.
This would explain partially why the adaptive immunity is not triggered.

Diphtheria toxin is antigenic itself.
So it can stimulate the production of protective antitoxin antibodies during natural infection.
In those patients without development of natural immunity, A subunit fails to bind EF-2, probably.

One reason is that the toxin does not get into bloodstream in 6-8% cases, and so natural immunity is developed.
So there is too low effective dose of diphtheria for some patients to invade the epithelium and trigger the adaptive immune response and create memory cells.

Sources: Murray Microbiology, Sherris Microbiology and Jawetz Microbiology.

Why do 6-8% of diphtheria patients not develop natural immunity after being infected?


texts:
Is there a maximum threshold of pain a Human can experience, beyond which point there is no noticeable difference?

I ask this question in part to better understand the definition of pain and its different facets, e.g. Is there a quantitative measure of pain? Are there various types of pain, or are they all part of the same fundamental experience?

It would also be interesting to know since I could perhaps be allowed to claim:

  "well at least I know I cannot feel more pain than X"

Thank you for your opinions.


texts: Is half-a-tablet of X a substitute for a tablet of X/2?

texts:
This may be anecdotal.

At the pharmacy earlier, the prescription called for a drug with X mg of the target chemical. The pharmacy however only had stock of a higher potency of the same brand.

E.g. A prescription may call for 25mg of a particular chemical, whereas the pharmacy could only service a request for 50mg of that chemical in the same brand.

According to the pharmacist, and the medic - a proportional fraction of higher potency drug of the same brand may be substituted for the lower potency. Thus in the example above, half-a-tablet of 50mg may serve in lieu of a single tablet of 25mg.

For a given brand

Is half-a-tablet of X a substitute for a full tablet of X/2?
Does the corollary scale upwards too?


texts:
Looking for sites with fossil data in the following categories.

Fossil cells
Fossil invertibrates
Fossil fish
Fossil amphibians
Fossil reptiles
Fossil dinosaurs
Fossil birds
Fossil mammals
Fossil insects
Fossil plants
Fossil mushrooms
Fossil humans

I would like for the sites to be copyleft (i.e. free, public domain, or creative commons type license) if possible, not necessary though. However, some museums such as the British museum are copyleft. Also, many other sites that google brings up are not working.

The sites I have found are mostly not copyleft:

American Museum of Natural History - Paleontology (4.75 million specimens) (very restrictive, only personal/educational use)
Paleoportal (aggregated stuff from the University of California Museum of Paleontology, the Paleontological Society, the Society of Vertebrate Paleontology, and the United States Geological Survey). This may touch on all of the fossil categories above.
Paleobiodb. (top categories: Mollusca, Brachiopoda, Arthropoda, Mammalia, Cnidaria, Radiolaria)
Fossil works
Florida Museum - Natural History Collections (botany, plus others)
Bryophyportal. Unfortunately, the images are only for personal/educational use. Looking for sites that allow free use of the content (such as copyleft licences like creative commons, or as public domain).
UCMP (not copyleft, personal/educational use only)

Wondering if these are good enough, or if there is anything else that should be added to this list to cover the categories above.


texts: Why do cells divide (or copy themselves)?

texts:
What I know

I learned about cells (not too much, but I've studied them a little bit. So don't feel offended when I say something which isn't really true. If something I write is wrong, please correct me (if it's not too much of effort).

Question

Imagine the first cell on earth.

Why would this cell "think" of dividing itself? How would a cell come up with the idea of dividing itself? The process of dividing itself isn't that simple, so ... how could that be? I don't really see a reason for devision from the "standpoint of a cell".

One of the solutions would be, that there's an intelligent creator, but I want to know the answer from the point of view from science.

Layman explanation would be appreciated

Just don't go too deep in the answer, I really just want to know if there is a solution to my questions. And if scientists really found out something, please just give me a very (VERY VERY) easy explanation.


texts:
Are there multiple copies of circular DNA and membrane bound ribosomes IN CHLOROPLAST ?
Are polysomes found in them ?


texts: Can rigor mortis change the anatomical position in which a person died?

texts:
I've been told as an undergrad in anthropology that the flexed position of the body in which some Neanderthal skeletons were found indicates that they were deliberately buried. Apart from the good preservation of the remains, one of the arguments for deliberate burial was that if the individual had died in this very flexed position during sleep, rigor mortis or post-mortem bloating would have caused the body, if not already buried, to extend (see e.g. Villa's [1989:325] comments to Gargett 1989). Barring sudden death by rockfall and ceiling collapse, this suggests that the body was completely buried before rigor mortis set in, or was deliberately placed in this sleeping position after rigor mortis faded by those that buried it.

But I thought I had heard in a biology course that rigor mortis stiffens the muscles, but does not contract them (see e.g. Faux et al. 2006). If someone died during sleep, could rigor mortis really straighten a highly flexed death position?


texts: What is the preferred way to abbreviate amino acids?

texts:
Amino acids are often denoted using either a 3-letter abbreviation or a 1-letter notation, e.g. Glutamine  is denoted via $\mathrm{Gln}$ or $\mathrm{Q}$.

When one notation should be preferred over the other and what are the reasons behind?

P. S. This is a follow-up to my question on Chemistry.SE Proper common notation for a ligand, where the problem of distinction between $\mathrm{L}$ notation for "ligand" and for "leucine" occured.


texts: Can exercise strengthen tendons and ligaments?

texts: Is is possible to strengthen tendons using exercise to prevent injury, for example preventing shoulder dislocation?


texts: NADH generated by glycolysis must be oxidized back to NAD+ in order for glycolysis to continue. What three positive pathways exist for this to occur?

texts:
I know where NAD+ is reduced to NADH but don't have the slightest clue as to three pathways where NADH is oxidized to NAD+.
If you could give me some guidance that would be great!


texts:
This would seem to be an easy to answer question, but I was unable to find an answer (in g/L) for generic double-stranded DNA or plasmid neither on Google nor on BioNumbers. I would expect the solubility to vary slightly based on the sequence or length, but it probably wouldn't affect it very much due to the relative hydrophobicity of the bases.

I know I have made solutions of plasmid maxipreps of at least 1µg/µl, and the Nanodrop DNA quantifier datasheet has a maximum DNA detectable limit of 15µg/µl, but can anyone find a source for the maximum solubility level of generic DNA? For example, the solubility of a specific plasmid of approx. 5kb in length would be a good ballpark answer for this question.


texts:
I notice that in a lot of bacteria testing procedures the sample has to be cultured. You place the sample in agar or another growth medium and wait for the bacteria to proliferate before examining them.

Why is this necessary? If the bacteria are present in the sample, can't you just examine the sample directly with a microscope to find them? Is it a needle in a haystack problem?

For example, a listeria bacteria is about 1 micrometer in size and has a positive gram stain. So, at 1000x magnification the organism would be 1mm in size in the objective which is highly visible. Even at 100x magnification you should still be able to see a tiny dot and be able to zoom in on the dot.


texts: Does trapper/hunter harvest reflect abundance or community composition?

texts: I'm working on a study where a single professional trapper removes furbearers and corvids (who the trapper is changes annually). I would suspect that the composition of the harvest would be strongly influenced by the individual's trapping style, ie. how and where they choose to set their choice of traps, as none of this is regulated. However, others argue that the harvest is reflective of species abundance and community composition. I'm having difficulty finding sources for either argument that aren't fisheries-centric. Can anyone suggest any?


texts: A 10mm long creature in the California dust

texts:
I observed this tiny creature burrowing through the dusty soil of Cachuma Lake Recreation Area in Santa Barbara County, California, on June 8, 2014, about 7 a.m. I have really no clue what it could be, other than an annelid, or newly hatched type of legless lizard or snake. But it seems too tiny for the latter. Yet, I would think an annelid would need more moisture, or different soil. Do worms live in dust? I watched it for about five minutes, maybe more. Burrowing under and re-emerging. So that seemed to be its normal environment.

Here's a closeup, and a link to a Youtube page I put up for it. Video on Youtube of animal's movement


texts: Photosynthetic efficiency and light harvesting efficiency

texts: Is there some sort of measure of the light harvesting efficiency (possibly like transfer time) that is directly related to the photosynthetic efficiency in some sort of equation? Also, how important is light harvesting efficiency to photosynthetic efficiency?


texts: Why does decreasing ion channel density result in an action potential not firing?

texts: I'm pretty confused, when i run a simulation of an action potential reducing the sodium and potassium channel densities gradually over time results in an action potential not being fired, and when i only reduce sodium channel density it stops the action potential from firing even faster. My question is why? what role does density have in firing an action potential?


texts: A synthetic sieve organ known as kliver?

texts: in this video at 5:28, the narrator talks about a "vat-grown all-purpose sieve organ" called Kliver that would do away with both liver and kidney transplant. But i don't seem to find online resources about the same. Is that terminology popular in scientific literature, and if so, how would synthetic biology accomplish that? articles about the same will also be appreciated.


texts: Does anyone know how I can get fungal extracts from fungal isolates? I have isolates in PDA slants and I'm gonna need to get their respective extracts to impregnate in sterile discs. I'm a novice in the field and all the help I can get will be greatly appreciated.


texts: Where are eosinophils and basophils phagocytic?

texts: It seems known that neutrophils circulate and are phagocytic within the blood stream, but I'm having trouble finding similar conconclusions about where eosinophils and basophils are phagocytic which are less common.


texts: What is the use of eye banks, if eyeball transplants do not exist at present?

texts:
Corneas are donated and transplanted, but not the eyeball.

I don't understand. What is the purpose of donating a cornea without an eyeball to a blind person?


texts: I am looking for examples of polyandrous insects?

texts:
This is for a homework assignment, and yet I am not able find any references that can help me find example of polyandrous insects.

Does anyone have any references or suggestions on where to look?


texts: Is pith a ground tissue with no specialized function?

texts:
Here is a question from the book My Max Score SAT Biology E/M Subject Test (where the SAT is the exam taken by American high school students):

  Ground tissue with no specialized function
  A. Xylem
  B. Phloem
  C. Cambium
  D. Bark
  E. Pith

Here, I can eliminate A, B, and D because these are dermal and vascular tissues while a ground tissue is what's between those.

As for the remaining variants, cambium is a tissue that gives rise to other tissues and is responsible for the plant's growth up and to the sides. Pith is a tissue in the very center of the plant stem and is responsible for storage of nutrients. While trying to understand the question, I even found info that it is a type of vascular tissue because it is involved in plant transport (https://www.quora.com/What-are-the-functions-of-piths-in-a-plant) although I'm not sure if it's correct (yeah, I know that Quora is not the website with absolutely credible info).

So, as I can see, both cambium and pith have their function.
Then, I decided to determine whether they are a kind of ground tissue. Pith definitely is a ground tissue, according to its definitions. However, I could not find what kind of tissue cambium was considered to be.
With all that said, I can't be sure to choose either answer. First, both tissues have their functions. Second, pith is a ground tissue, and cambium is undetermined for me.
Here is the answer, however:

  E. Pith is a source of unspecialized ground tissue that adds structure
  to a stem at the very center.

I can't be sure about this answer because unspecialized means "not designed for a particular purpose." But, as I've pointed out, both pith and cambium have their purposes/functions.
Please explain why pith is written to be unspecialized. Is it because "storage" is not an "active" function like growth or transport; this tissue just exists and is able to store different substances in addition to that?

Also, is cambium a ground tissue or some other type (dermal, vascular)?


texts: How can the phenotypic effects of a tumor suppressor mutation be silenced?

texts:
I've been reading a little about the "two-hit" hypothesis for tumor suppressor genes here, which mentions that some genes exhibiting haploinsufficiency are exceptions to the hypothesis. I've read elsewhere on this site (namely the answer to this question) that suggests haplosufficiency as a means of "silencing" the mutation of the tumor suppressor gene such that the expression of the wild-type allele compensates for the mutant allele.

Are there any other mechanisms that contribute to incomplete penetrance of tumor suppressor mutations?


texts: Why magnesium ion is needed for activity of G-proteins?

texts: I was studying about G-protein coupled signaling sysytem, somewhere they have mentioned about need of Mg$^{2+}$ for acticty of G-protein and related it to increase of cyclic AMP production. On further reading I came to know that the said ion is related to GTPase activity of G-protein, but how does it relate to incresed cyclic AMP production?


texts: If cancer cells have telomeres are they different than the telomeres in non-cancerous cells? Would cancer cell telomeres be somehow 'set-up' to function almost indefinitely; in other words are 'they' very 'robust' or 'durable'? If these cancer cell telomeres are 'durable could their functioning cause any apoptosis mechanisms to 'shut down'?


texts: How to find a PDB structure of a protease with a peptide like inhibitor

texts:
I wonder how, for purposes of just illustrating some concepts like substrate alignment in the catalytic triad active site, I can quickly and efficiently find a protease structure (irrelevant of what organism exactly) that has a peptide like inhibitor on the PDB database.

Hints appreciated.


texts: Why does spraying water on plants help them survive in case of frost?

texts:
I've heard that spraying water on plants will help them survive the frost. Why is that?

Some say that you should do it in the morning right before the sun rises, and others spray water the whole time of low temperatures.

What is the explanation for why this spraying techniques works?


texts: Strange planarian/leech like creatures found with California blackworms

texts:
I've been trying to ID these things myself but to no avail.  They came with a shipment of California blackworms from Florida.  I've heard so many ID's and apparently it's not uncommon to get these kinds of flatworm like hitchhikers with blackworms, but apparently different suppliers have different hitchhikers, so what one layman claims they are doesn't necessarily apply to another supplier.
I've heard these guys are planarians, leeches, or some sort of parasite specific to blackworms. I can probably eliminate most of these guys, but I just noticed they gave "birth" or something.  I thought they reproduced via fragmentation, but I saw one with what looked like legs, and realized it was actually dozens of smaller babies wiggling underneath.
I'm worried, because I don't want them to kill my blackworms, or accidentally kill my fish.
The creatures are about a half an inch stretched out? the creature is inside of a standard 3ml pipette in the later pictures. They tend to wiggle back and forth (see the video). They scrunch up into a small ball when I disturb them.

It's hard to tell because they are transparent, but the below gif is definitely the same type of creature.   Basically half the time I see them, they stick their heads out of the water and wiggle back and forth like that (but not sway, like the blackworms).   My phone isn't good enough to capture this behavior well.

https://imgur.com/a/4S4EPBB


texts: Interpretation of table on analysis of genetic diversity between groups

texts:
I am very confused about how to interpret Table 8.3 in Smith's Evolutionary Genetics.

Is the GST in the table the same as the G,ST (with the comma), which is defined (pg. 156; Box 8.3) as "the probability that two genes drawn at random from the same deme are identical"?  If so, is it not the same as Hs, the probability that two homologous genes from the same deme are identical?  If it is the same, why do they differ?

And why would Hr be larger than Hs?  That is, why would a gene be more likely to be identical with a gene from a different deme than the same deme?  Doesn't this suggest negative assortment?

Thank you very much to anyone who can help!

This is the table:


texts: Finding different Proteins with same function

texts:
Could you help me about finding two different proteins that coming from different ancestors, perform same function?

Thank you


texts: Coronavirus: Why does soap inactivate the virus on skin, but not on surfaces?

texts:
In a comment on "Stability of SARS-CoV-2 in different environmental conditions", published today in The Lancet Microbe, it is stated that household soap is highly effective on the skin. Not much further down the same paragraph it is noted that soap cannot be used as a surface disinfectant for SARS-CoV-2.
So why is it so effective on hands, but so ineffective on a sink?


texts: I'm unsure whether to call it a fruit or a vegetable. I found it on the road in a neighborhood and decided to pick it up before a car squashed it. (Thus, my initial guess was a squash.)


texts: Would we know about a virus that causes no symptoms?

texts:
I've heard that there are a number of viral illnesses that humans can get from animals, which cause no symptoms in the animals. If there was such a virus in humans, which was very widespread but caused no symptoms, would we know about it?

As far as I know most pathogens have only been discovered when people were specifically looking for the cause of some disease. With bacteria, I think we know / can discover any that can be found in a human body, though we don't necessarily know what each type does. But viruses are much smaller.


texts: How to find the reaction rate in an enzyme reaction?

texts:
First time posting questions here, so let me know if I need to edit anything.
I need to decide $dC/dt$ and $dP/dt$ when the reaction is like this, where I don't have any info about $S, E$ or $P$:
$$2S + E \overset{k_a}{\longrightarrow} C \overset{k_c}{\longrightarrow} 2P + E, \quad C \overset{k_b}{\longrightarrow} 2S + E$$
Is $dC/dt = 2k_a SE - (k_b + k_c)C$? Is $dP/dt = 2k_cC$? Thanks in advance.


texts:
I try to get a picture of the life cycle of a protein (considered as a specific molecule).

This is how I can imagine it:

After the cell is born a protein molecule is synthesized by gene expression for the very first time de novo. This happens at a specific point in time and in space, typically at an ribosome, which may be located anywhere inside the cell.
From the location of its generation (combination or recombination, see below) the protein travels to its final destination, e.g. as an ion channel in the cell membrane. (But possibly it was already synthesized very close to its point of use.) Or it just floats around in the cytosol. (Possibly, it gathers some other biomolecules around it.)
Whereever it arrives or not: the protein lives and works for some time.
Eventually, it gets damaged (= looses small functional units), but gets repaired in situ. Continue with 3.
Eventually, it gets marked by ubiquitin and destructed in a controlled manner. Continue with 7.
Eventually, it decays spontaneously (= splits into some larger fragments).
Its fragments are released (in case it was bound) and start again to float around in the cytosol.
Eventually, its (or other proteins') fragments are recombined (at specific points in time and in space, possibly at "re-factories" comparable to the ribosome-"factories"). Continue with 2.

Is this rough picture of the life-cycle of a protein essentially correct?

If so: What is known about the time ranges in which these processes take place? Especially: How long is the effective life and working time of typical proteins? Are there proteins that live and work only for minutes or hours, and others that live for months or years? (Specific examples are welcome!)


texts: Do pale skinned people show other low light adaptations?

texts:
So, pale skin is, fundamentally, an adaptation to living in low light conditions. Pros: reduce energy spent on producing melanin, increase vitamin D production. Cons: more vulnerable to sunburns and skin cancer.

Do populations with this sort of adaptation have an increased rate of other low light adaptations? Specifically, I'm thinking of vision in low light situations. Examples of possible adaptations: increased rod count in the retina (pro: better low light vision, con: worse bright light vision), or faster production/resetting of rhodopsin (pro: better low light vision, con: greater energy expenditure).


texts:
I have got a pet tortoise and I was wondering if any one could identify it. I think it's a male around 2 years old.

I'm not quite sure, it is quite small, very shy and goes very fast.

He likes carrots, pears, apples and tomatoes.

At the bottom of his shell there's sum light orange color.

Basically light line of orange on each side but only on the bottom of his shell.

If this helps at his last owner house he was bitten by a dog and his shell was repaired by a local farmer with fibreglass.


texts: Do individual neurons communicate with the origin of thoughts?

texts:
When mapping the different neural pathways in the brain, often pictures such as these are drawn:

Or similar versions. Clearly these sketches draw the neural pathways as being a two-sided connection, as can be judged from the double arrows. I was wondering, how such bidirectional pathways work. Specifically, I am interested to know whether individual neurons constitute such a bidirectional pathway between different parts of the brain, or if the bidirectional pathway can be thought of as a 'circuit': a pathway of neurons that eventually comes back to a certain part of the brain.

This question is especially interesting in light of abstract thoughts. Let's make some extremely generalising (and ludicrous) assumptions and assume that our conscious thoughts are governed by our hippocampus only. That is, we assume that thinking about a matter without input from sensory neurons causes the hippocampus to fire an action potential into some specific cluster of neurons (somewhere in the brain). E.g. we assume that thinking about the letter 'A' causes the hippocampus to fire an action potential into the cluster of neurons that represents the letter 'A'. Let's also assume that the memory we have regarding the letter 'A' must be returned to the hippocampus, in order to continue our thought process. For example, I might want to recite the alphabet in my head. Starting with the letter 'A', I then continue to the letter 'B', which arises in my conscious thoughts as a result of the firing of the cluster of neurons that contain information regarding the letter 'B'.

So if we assume the circuit, conscious thoughts $\rightarrow$ cluster of information fires $\rightarrow$ conscious thoughts to exist, then how would its feedback most likely work?

Let's take the example where we think of the letter 'A' and want to think of the letter 'B'. I have sketched two different theories about how the communication between these two clusters of information and the 'governing body of thoughts' (which I assumed to be the hippocampus), might be:

The difference is the following: in the second theory, all individual neurons are expected to be able to communicate directly to the hippocampus. Whereas in the first theory, the feedback to the hippocampus arises only when we have reached our destination: the letter 'B'. Clearly, if we assume that a specific thought process is able to self-induce action potentials (of course, this is highly debatable), at least one of the two theories must be partially true. For which one exists evidence?

My first intuition would be to say that the first theory is more likely, but this is ambiguous under Dale's principle: why would only some cells be connected to the hippocampus? On the other hand, I found it hard to believe that every individual neuron is directly connected to the hippocampus.

So now that I have explained my thought process, my question can be formulated as follows:

  How are clusters of neurons that are involved in abstract thoughts bidirectionally connected to the thought-governing-body (whichever actual part(s) of the brain this is)? Can we say that just a single neuron in the cluster provides the feedback to the thought-governing-body, or is every individual neuron that is involved in conscious thought potentially capable of a feedback loop?

Disclaimer: Yes, I'm not up-to-date to all the latest advances in neuroscience. Yes, I'm aware that my question might be ambiguous with respect to all the different types of neurons, connections and theory about neuronal networks and micronetworks. My question, however, is concerning the likelihood of the theories I presented. For which one do we have evidence. Are both wrong? If so, in what way? Are both right? If so, when does their difference play a role? etc.


texts: Disease causing variants and Hardy-Weinberg Equilibrium

texts:
Is it true that many disease causing variants/mutations do not follow Hardy Weinberg Equilibrium?  If so, then please elaborate on why this may be true (or not) and provide examples.

I am interested in single-gene disorders or those linked with single nucleotide variants.  I was told that many disease causing variants/mutations do not follow Hardy Weinberg Equilibrium, but I cannot find any documentation showing this (so I am looking for a reference on this matter).  In particular, I have considered Huntington's disease, Sickle cell anaemia and Hemophilia, but have not found any special relationships with these diseases and HWE.

Thank you.


texts:
I was watching Sherlock Holmes - A Game of Shadows yesterday. I saw that he had developed a serum that causes a  person to react like he has been injected with adrenalin.

Watsons's dog fainted, I think, and the moment Holmes injected the dog with this serum, it jumped up and ran away.

So my question is: Is it possible to extract adrenalin, or was it a steroid?


texts: How to compare Smith–Waterman algorithm implementations?

texts:
Assume that you have two implementations of the Smith–Waterman algorithm (with what ever heuristic they apply to speed up) for local sequence alignment of genomic sequences.

I would like to know if one can be certain that these implementations do a good job of aligning (i.e the program has been correctly written). How do I benchmark this?


texts: Converting fmri data to association matrix

texts:
I am currently working on a new tool for the analysis of (large) weighted networks. Association matrices (correlation matrices) as obtained from fMRI data are perfect examples of the kind of data I am looking for. Unfortunately I am only able to locate raw fMRI data and the task of converting them is way outside my expertise.

Can anyone point me to a place where such converted data can be found, or where I can download software which automatically converts the data? Preferably a dataset divided into control/disease.

Thanks!


texts: What is effectiveness of methyl-alcohol as sporicide?

texts:
Methyl-alcohol is the weakest alcohol in terms of bactericidal properties. However, I have read that it also works as sporicide.

What is the effectiveness of methyl-alcohol in killing the spores of fungi and bacteria compared to other substances and what is the best dilution?


texts: What (if anything) about tuberculosis makes producing a highly effective vaccine difficult?

texts:
What about tuberculosis makes it difficult to produce a safe vaccine that is effective at producing an immunogenic response in >99% of individuals against all strains of the bacteria?

I am aware of the BCG vaccine which has a variable efficacy depending on how it is measured and am aware of the 4 current vaccine candidates (MVA85A, rBCG30, 72F fusion protein, and ESAT6-Ag85b fusion protein). I am curious about the very specific question of aspects of the bacteria that make the TB vaccine difficult.

Many, many thanks.


texts: Why both forward and reverse primer are added in asymmetric PCR?

texts: If the purpose of Asymmetric PCR is to amplify single targeted strand of dsDNA then instead of adding just one primer for targeted strand why do we add both forward and reverse primer? Upon addition of only one type of primer won't we will get linear amplification of that strand?


texts:
I have often heard that right and left ovaries alternate in releasing ovum.

Is it always true? What controls this rhythm? Is it simply because the other ovary is unresponsive to LH or FSH? If so, why?


texts: Study case of the inheritance system of Oenothera

texts:
I've been told some interesting facts about oenothera. Apparently in this species some lineages have been through some translocations and in results to these translocations and in consequence, some chromosomes are inherited exclusively through the female function while some other chromosomes are inherited only through the male function.

Can you please provide a summary description of how things work in this species concerning the meiosis, the haplo-diplontic life cycle and the recombination?


texts:
I saw a video where an ant lost its head and was still walking for some time.

If this is possible for an arthropod, what keeps it from working with a vertebrate? (Humans, especially)


texts: In a typical model ecosystem, what might the percentage of plants be to top predators and everything inbetween?

texts:
I'm not sure if this will be a simple question that is almost a natural law for an ecologist, or a complex serious of assumptions.

I vaguely remember from school that only 10% of the energy is converted to biomass at each 'level up' however I have never seen any academic support of this. Lets say we have a fairly representative model ecosystem. In a pyramid of biomass, what percentage of biomass would I expect to see at each level (top predator, primary predator, herbivores, plant mass)?

An additional part I would like to know is does this ever correlate to the ecosystem of any given tier. i.e typically 5 predators will be found in the same area as 20 herbivores rather than 10% of predator biomass for 100% of prey.

There are plenty of diagrams available on google, but I have yet to see anything that looks credible. Any citations to academic sources would be greatly appreciated.


texts: Is there any explaination to homeopathies in modern biology sciences?

texts:
I'd like to know if there is any sort of explaination from rigurous biological arguments which could potentially explain how homeopathies could work?

I'm not talking about placebo effects (psychological) or "water memory" (purely hypothetic), but really about the immune system itself.

Usually, there is only 1, or a really insignifiant amount of toxins after the dillutions for the homeopathies.
But does that mean that there is absolutely no effect on the organism, biologically talking?
Or could there be some immune memory taking place here for example (ik it is usually in adaptative reaction with the lymphocytes, but does it happen with the white cells or other stuff)?

I'm just curious about it :), thanks!


texts: Do Vaccinium membranaceum plants need a minimum amount of darkness per 24 hours?

texts:
I have Vaccinium membranaceum (black huckleberry) seedlings growing in a greenhouse. I have the option of providing fluorescent light to the plants 24 hours a day.

However, it has occurred to me that plants like Vaccinium membranaceum might require a minimum amount of darkness per 24 hours.

What darkness requirements do Vaccinium membranaceum plants have?


texts:
Why do mammalian skeletal muscles have t-tubules at the junction of the anisotropic and isotropic band, whereas non-mammalian muscles and cardiac muscles have it at Z-line? What could have been the functional significance?

If skeletal muscle would have it at the Z-line then I think it would have been more effective in contraction of muscle fibre. So which arrangement is more efficient?

Also, why is a common arrangement (the more efficient one) not seen in all those muscle types?


texts: Why aren't native predators in Australia able to handle the mice problem?

texts:
Australia is currently dealing with a mouse infestation problem, but Australia is awash with different types of predators that presumably eat lots of mice like animals.  Snakes in particular are well suited to kill mice, especially in close quarters. Snakes can fit in places most other predators can't due to their size. Additionally large invertebrates (like huntsman spiders) should also be able to take on some of the mouse load.
And it would be one thing if this was the first time the population ever boomed like this, but mice population booms have apparently have happened since Australia has existed. So why aren't we seeing large spikes in those predators when mice populations boom like this?


texts:
I'm not much of an ornithologist but I know enough to distinguish most Central European birds of prey. To me it is amazing that there are so many species that seem to occupy the same niche. Especially the two native kite species (Milvus milvus and Milvus migrans) and the common buzzard (Buteo buteo) are -- to my impression -- quite similar in terms of size, preferred prey, habitat etc. According to the competetive exclusion principle, these species would not coexist if they would exploit the exact same set of resources. So my question is:

What are the major differences between the mentioned species that allow coexistence? Are there more such examples from other geographical regions?


texts: In what ways, if any, does administration of rapamycin *not* mimic calorie restriction?

texts:
Numerous sources like this say that rapamycin increases lifespan. And mTOR antagonism appears to be a large part of this (mTOR antagonism also appears to be a large part of calorie restriction's mechanism too).

Is the effect of calorie restriction equal to that of rapamycin treatment or are there differences?


texts: Differences between right and left handed people

texts: Are there any articles reporting any significant differences in behavior, attitudes, intelligence, appearance, etc., between right and left handed people?


texts: Why bacteria and viruses are so much smaller than animal cells?

texts:
Why are bacteria and viruses so much smaller than animal cells? -
I don't have more information about the question, sorry if this is too vague.


texts: Could the denaturation of protein during cooking could generate a prion, by any chance?

texts:
It may sound silly, but it appeared to me as a theoretical possibility; not a practical fear.

On a healthy and correctly folded protein if cooking process is applied (that includes heating and mixing with various other things), is there by any chance a possibility to develop a prion?


texts: What are the differences between isozymes, allozymes and isoforms?

texts:
As far as I have understood

Isozymes are derived from different genes but perform similar functions
Allozymes are derived from the same gene but different loci, functionally conserved
Isoforms are a result of post transcriptional modification of the same gene, I am not sure for its functional conservation.

Are there anyother things to know about them?
Thanks


texts: Why does ATP contain ribose rather than deoxyribose?

texts:
I read in a textbook that ATP is made from ribose and not deoxyribose. Originally, I thought that the pentose sugar didn’t have functional importance.

Is there a functional reason why the ATP used in metabolism has to be made from ribose?


texts:
Obviously, humans can survive underwater for a short while. I've assumed this is because at some point it benefited us to stop breathing momentarily, and so we evolved a respiratory system that was able to take short breaks.

Similarly, fish can survive outside of water for a short while. However, I can't think of a single instance for most fish where they may have needed to evolve that ability. Even their ancestors originated from aquatic environments, so I don't think it's a residual ability they no longer need.

Why did fish evolve a respiratory system that could take breaks like ours can?


texts: Can I change the genetics of a group of plants naturally?

texts:
I have been thinking about introducing all sorts of types to certain environments where the plants will have to adjust to survive.

For example having a dark area with one light source right next to the plants so they all want to grow towards the light.. however this could be made more difficult by either introducing slight angle adjustments or artificial wind (custom controlled fans).

Would it be possible to start slowly introducing such challenges to change the plants? for example strengthen their stems to be able to fight the gravity or wind?


texts:
I'm interested if there is a way to degrade the plasmid DNA inside an E.Coli cell specifically so that the method does no harm to the chromosomal DNA. First I was thinking about restriction endonucleases but I'm afraid that;

it isn't specific enough and kills the cell
or it does nothing, because the E.Coli methylates the plasmid DNA too

My second thought was the CRISPR/Cas9 system but it sounds like an overcomplication of the problem. Any simpler ideas? (For eg. specific enzymes)

EDIT: the main idea is to create more competent E.Coli cells with directed evolution. Currently this is just a thought experiment, so there is no specific plasmid sequence. In details; I would transform the plasmid into the cells, then do the selection part with an antibiotic and let them grow, then transfer the cells into a medium where there is no antibiotic and add IPTG to induce the plasmid-DNA-hydrolase enzyme, then maybe an other selection part could be performed to remove the cells which still contain the plasmid (for example with FACS if there is a GFP gene on the plasmid), then make the cells competent again with CaCl2 and do this whole process over and over again.


texts:
I am a computer scientist with no biological background and working on analyzing lab  results of patients with Acute myeloid leukemia. They have been tagged with following subtypes of AML:

AML with No maturation
AML with granulocytic differentiation
AML with monocytic  differentitaion.

I know there are two classifications for AML subtypes: FAB(M0-M7) and WHO. I think these patients have been classified using FAB, but their corresponding subtypes' names do not match in any of the names associated with M0-M7:  http://www.cancer.org/cancer/leukemia-acutemyeloidaml/detailedguide/leukemia-acute-myeloid-myelogenous-classified.

I checked a lot of literature but still not sure about the class of the last two tags in FAB classification. Could someone please help me with that?

"AML with No maturation"  is M1?
"AML with granulocytic differentiation" is M2 (or M4, M5) ?
"AML with monocytic  differentiation" is M4 or M5 or both ?


texts: Why does the pH decrease, when adding pancreatin to different types of milk (cow milk, soy milk etc.)?

texts:
I'm experimentally observing how pancreatin affects the pH in different types of milk.
Why does the milk's pH decrease when I add an enzyme solution to different types of milk (e.g., cow milk, soy milk etc.)?
I am not sure how to explain this reaction.

Thank you for your help.


texts: Are there any traces for evolution in modern humans over the last 100 years?

texts: I ask that because I had a biology class and my teacher said something about a bone in the back of the head that apparently every male has, and for some reason, in the last 20-25 years, its started to fade away and so even though my father has the bone I don't. Or when I was still in high school, and I had to do X-rays for braces the doctor told me that I don't even have wisdom teeth? Are those traces of evolution or are they just random mutations?


texts: Does the preservation fluid (ethanol or formaldehyde) leach heavy metals from mollusc tissue?

texts:
In a thread on researchgate, the concern was raised that long term exposure to unbuffered preservation fluids such as ethanol or formaldehyde may leach heavy metals from biological samples due to a reduction in the fluid's pH. Can anybody tell me if this also applies to mollusc samples? I would assume that carbonate shells function as a pH buffer and thus keep the fluid's pH relatively stable over a long time.

Edit: Link to the researchgate thread. No research articles were mentioned in that thread.


texts: Why do mice have a higher metabolic rate than humans?

texts:
Mice and other small animals have higher metabolic rate than humans.

How does that happen on cellular level, if we look on one cell in the mouse body?

What is it in this cell that will be different?

How is that regulated inside mouse cell?


texts: What is this? Is this a part of the tubular heart? Does it pump hymolymph? Does it have ostium?


texts: Is natural selection still at work in humans in the 21st century?

texts: There has been some disussion on this site about some aspects (e.g. evolution of eye sight, or height, or the effect of medicine, or evolution the past $\sim10000$ years). My question is really more general regarding evolution and more specific regarding the current age. I'm looking for answer with references to original research if possible.


texts: Main methods used to predict functional annotations in GO

texts: Can someone provide me some information about the main method used to predict the inferred electronic annotations in Gene Ontology?


texts: How are blood vessels affected by UV and infrared radiation?

texts:
The lining of the blood vessel as an interface and boundary layer is of existential necessity to the life-support of mammals.

My question is:
How are major blood vessels and the blood vessel lining affected by sun-irradiation in humans, when exposed through equal or less than a millimeter of skin in total (including subcutaneous fatty tissue)?

Information regarding infrared exposure is welcome too.

Source: http://www.dermatology.ucsf.edu/skincancer/General/prevention/UV_Radiation.aspx

Thanks.


texts: What is the blood ejection speed outward from human body vein?

texts:
At what height blood can eject from human vein ?
I see, sometime there is direct blood transfer from one person to patient.
So sometime blood bottle is kept at certain height and blood is transfered from person to upper bottle and then from that bottle to patient directly.
At what height blood can go ?

EDIT

For example, I had not mentioned before,
What would be the blood pressure outside from body after cutting certain nerve or vein or whatever which carries blood-speedily, when we go inside vacuum chamber ?
Consider any chamber where you will be able to remove air/atmosphere inside it and a person is provided with oxygen cylinder. Now what will be the blood ejection speed outward from the body ? At what height ? You will have to consider atmospheric pressure also when we leave normally on earth. So question is, at what height in vacuum (where there is no pressure from outside world) ?


texts: What is this plant, and should the lowermost leaves be curling up?

texts:
We've got a couple of these plants but have no idea how to look after them. Watering them regularly (every 2-3 days, or when the soil seems dry) seems to help. The pot rims are about a foot at their widest part.
However, we're concerned about the lower leaves drying up. Is this a normal part of this plants growth process and does it continue this way and produce a 'trunk' of sorts?
As a follow on question, do we need to re-pot these plants?


texts: Number of beneficial mutations cataloged?

texts: I can see from Wikipedia that there are possibly thousands of harmful mutations that have been cataloged and linked to disease. There are also unnumbered neutral mutations. But, does anyone know how many "beneficial" mutations have been cataloged in scientific literature?


texts: How does a spider's legs not get caught in silk when wrapping prey?

texts:
When a spider catches a prey, it wraps it up in silk. It uses its legs to do this. So how does its own legs not get stuck on the silk?

Note: I'm not talking about walking around the web. There are non-sticky anchor strands of silk to walk on. I'm talking about when the spider actually wraps something up.


texts: What percentage of human capillaries are located in the skin?

texts:
As in the subject line, what percentage of capillaries in a human (expressed in terms of total length, I suppose) are located in the skin, as opposed to internal organs?  Google scholar has not turned up anything obvious, but I'm an outsider so I may have missed the appropriate term.

Another followup question would be:  if we're considering the amount of energy expended by the heart in pumping blood throughout the body, what's the percentage of that energy that is devoted only to (1) transporting blood to the skin and (ii) circulating blood through the skin via capillaries?


texts: Does physical exercise of a specific part affect muscles in the other parts of the body?

texts:
There is a theory among bodybuilders, that is, if you train big muscle groups (e.g. legs, chest), it will increase the overall growth of muscles all over the body; the trained muscle will release signals (what are they?) into the blood stream and in turn, triggers the release of muscle growth/repair hormones (insulin-like growth factor?) which have effects on any (skeleton) muscle cells.

Is this story true?
Will the muscle growth/repair hormones also enhance the smooth muscle or cardiac muscle?


texts: Is cell senescence in culture comparable to that in vivo?

texts:
A cell is 'senescent' when is has permanently left the cell-cycle. This can be caused by stresses, or by reaching the 'Hayflick limit' (the cell has reached its replicative lifespan, as defined by its telomeres).

Cells cultured in vitro can be used as models to study senescence (or sometimes 'ageing', although the distinction there is not necessarily within scope of this question) by growing the same population of cells for a long time (many passages). A common method to identify a senescent cell population is to use beta-galactosidase staining.

I was wondering to what degree senescent cells in culture (identified by beta-gal staining) are actually comparable to those you might expect in vivo. I ask because it seems to me that a terminally senescent cell may not actually survive long in an organism, so what we refer to as senescent cells in vivo are actually pre-senescent cells? I haven't got any basis for this, just a feeling. (Very scientific I know).


texts: Why do I see so many handicapped dorbeetles?

texts:
Living in southern Germany, I often visit nearby forests and pastures.
From early spring to autumn, I frequently see lots of dorbeetles on my wanderings. An estimated amount of 50% of those bugs seem to be somewhat handicapped or crippled. All of them share the same symptoms:

They stretch their legs away from their body, moving them in a
swimming-like manner, which causes them to be unable to get over the
smallest rocks or plants. It looks very clumsy, almost drunk. Often they draw back one of their rear-end legs, getting caught in parts of plants.
Many of them are lying on their backs, struggling to get back on
their feet. When I turn them around, they will start walking in the
fashion I described above, falling over again almost instantly

Like already pointed out, not all of the dorbeetles behave like this. I see lots of bugs that seem to be perfectly fine, too.

What can possibly cause this?


texts: When does weak selection produce qualitatively different results from strong selection?

texts:
In evolutionary game theory, it is typical to model organisms as having a base fitness that is modified slightly by the game interaction. The ratio of the game effect versus the base fitness determines the strength of selection, with weak selection meaning the game modifies overall fitness only slightly, and strong selection meaning that the game payoff is a big part of the overall fitness of the organism.

Most analytic models like to assume weak selection because it allows the authors to Taylor expand the selection function and linearize it by dropping terms that are higher order in the stength of selection. However, it is unclear that results derived for weak selection would necessarily hold under strong selection. Are there mathematical (or computational) models where weak and strong selection produce qualitatively different results? If not, is there an argument as to why weak and strong selection should produce the same results?

I've also seen this discussion come up outside of evolutionary game theory, in a more general biological setting. In particular, with respect to inclusive fitness. The take away message I got was that in the regime of weak selection relatedness means what you expect it to mean, but for strong selection the concept becomes very slippery and counter-intuitive. What does inclusive fitness theory tell us about going from weak to strong selection? Again, I prefer arguments supported by clean mathematical or computational models over ones based on intuition and words alone.


texts: What is the signal conversion from hair cells to cochlear nerve cells?

texts:
If I understood correctly, inner hair cells generates a graded potential (receptor potential), this potential maps the stereocilia deflection. On the other hand, the cochlear nerve cells transmit action potentials to the brain.

The question is how and where the graded potential is converted to action potentials. In particular, as action potential signals are characterized by the interval between triggers, how are the sound properties (power and frequency) mapped into this interval?


texts: Is there differences in components of saliva among species

texts: Are there differences in the components of saliva among species? Also, do the functions of saliva differ between species?


texts:
I have a background in product design and so am familiar with with how most things are mass-produced — food, machines, etc.  But I've been able to find very little information on how vaccines are mass-produced.
It looks like there are 4 types of vaccines, all of which include pieces or byproducts of the virus they're intended to counteract.
If you're producing billions of vaccines, I imagine you need a tremendous amount of the virus.
How is such a mass of virus obtained? Do they just fill up tanks with a culturing agent and a sample of the virus and wait for it to grow, like a giant petri dish? Are there big vats of Coronavirus sitting in factories somewhere?


texts: Is olfaction same among different individuals?

texts:
For instance if I smell the fragrance of a rose, well it smells like roses (little bit sweet).  But is that smell the same for other people?

Because we also have different voices, why not have different olfaction.


texts: Clonal and subclonal mutations in cancer

texts:
Likely this will sound as a silly question, but I don't know whom to ask. Ok, here it goes.

McGranahan et al link found that tumors with high clonal antigen load are more likely to respond to the immune checkpoint blockage.

Bozic et al link (at the same time) proposed a probabilistic model to determine the number of clonal and subclonal mutations. They found that fast growing cancer types (where growth is cell division over cell death) are more likely to generate a higher number of subclonal mutations.

Knowing that melanoma and NSCLC are fast growing cancer types, these results seem to contradict each other. We know that they are fast and we know that both melanoma and NSCLC are cancer types where immunotherapy is most effective.

Plus, probabilistically how likely it is for a certain cancer lesions to have lots of shared mutations? A totally genetically homogeneous lesion with no branches with a very high number of mutations.

Or (much more likely) I'm missing something.


texts:
I'm now designing primers for PCR. I use Oligo analyzer to check the primer secondary structures.

Ex: Delta G:  -4.16 kcal/mole  Base Pairs: 4

5'        GCCGTCTAGCAGCACATAATG
            :  ||||  :
3' GTAATACACGACGATCTGCCG

So my question is with delta G = -4.16, how do I know how much temperature degree can break these bonds?


texts:
I recently heard a proposition that fasting (especially fruit-only diet) can improve liver function because it removes the load usually induced by toxins in common diets, thereby allowing the liver to regenerate itself quicker.

This is a common proposition in "detox diets" but I am not sure if it has any ground in science? Does consuming less toxic food allow liver to "recover" and regenerate quicker?


texts: How did the largest/longest dinosaurs hold their head and necks up?

texts:
After seeing the images in the articles shown below, I am having a tough time understanding the mechanics of how these incredibly long and heavy necks can be supported outstretched like this. A rigid beam or tube would remain fairly straight through compression on the bottom and tension on the top, and since there is muscle, tendon, ligament and bone, I know the necessary mechanical functions are there somehow.

Is there one "neck muscle" along the top that holds the neck "up", or many short muscles between vertebra? Where is the origin of the tension, the shoulders or the pelvis, or is it all the tension distributed along the whole spine from neck to tail?

How does this work??

above: Titanosauria of Chubut from here.

above: A reconstructed Patagotitan mayorum, a 70-ton dinosaur discovered in Argentina. (Courtesy of José Luis Carballido) from The Washington Post article Which dinosaur is the biggest? There’s a new contender — and it’s alarmingly large.

above: A reconstruction of the newly named titanosaur Patagotitan mayorum. from The National Geographic article New Dinosaur Species Was Largest Animal Ever to Walk the Earth.


texts: I have two animal running trajectories. A regular one with repeated back and forth running between point A and B, like the one on top in the figure. The other one is very irregular, animal paused and turned around a lot in the middle. Is there any algorithm to measure the regularity of a trajectory, like repeated activity on the top? And compare the extend of regularity between the two trajectories? Thanks in advance.


texts:
I'm not sure how to measure genetic distance. There seems to be many different equations out there, and all the ones I found are rather old.

In my specific problem I want to see if the twist in collagen differs if the species are different. (I have a program to predict collagen twist according to amino acid sequence)

I therefore want an objective numerical value to base my comparaison on. "Nei's standard genetic distance" seems good, but it is very old so I was wondering if there was a modern alternative. Is there an R package or something like that to calculate it automatically?


texts: Can an epileptic seizure start in the spinal cord?

texts: My understanding of an epileptic seizure is caused by "invalid electrical signaling" in the brain. Can these start from the spinal cord  (outside the brain) and move into the brain and cause an epileptical seizure? (sorry for not using the right terms)


texts: Is hunger pushing cognitive ability in humans?

texts:
We have a lot of those questions here that base on personal anecdotes and I try to avoid asking any of those. Still, after skipping breakfast and an extremely effective work day so far I started wondering.
I have always felt, that for most cognitive tasks I perform best before breakfast. Of course some of it is sure related to being very awake and supposedly having a biorhythm that favours working in the morning, but I have always related this to not having eaten and also surprisingly not feeling hungry at all until basically deciding to eat "because I really should eat something" around noon.
So today I decided to find out, if this phenomenon is more widely known or just anecdotal for me. Of course there is a lot of information on how digestion makes you feel tired and you should not expect to be very productive directly after eating. That was not what I am looking for.

Finally I found this 2006 NY Times article about "Empty-Stomach Intelligence", where it is stated that at least for mice being "mildly starving" seems to increase cognitive ability based on the hormone ghrelin targeting not only the hippothalamus, but also the hippocampus.
I then tried finding a relevant publication and was only lead to this one, describing the original study about ghrelin influencing food intake, but seemingly not the "sidetrack" of it influencing cognitive abilities during starving.

Now I am lost. Is there any newer publication about this phenomenon that I completely missed, possibly even in relation to how humans can perform cognitive tasks while being mildly starved?


texts:
Centromeres move toward the poles as the microtubules that connect them shorten. This shortening is due to the removal of tubulin subunits from the kinetochore ends of the microtubules.

I'm confused as to how the centromeres can be pulled closer to their respective poles while tubulin subunits are being removed. To me, this is similar to pulling an object by a rope while simultaneously cutting pieces of the rope out. How do the centromeres remain connected to the spindles while tubulin subunits are being removed?


texts:
is there a relationship between taxonomy and the presence of stomach in marine fish? In other words, are stomachless fish present in only certain phylogenies or are stomachless fish scattered throughout the fish classes (Class Agnatha (jawless fishes); Class Chondrichthyes (cartilaginous fishes); Class Osteichthyes (bony fishes))?
Thank you for your time!


texts: Why the sense strand is only involved in transcription though the antisense strand just has the compliment strand of the sense strand?


texts: Meaning of letter "c" in description of mutation: "Homozygous c.195C>G; (p.Cys65Trp)"

texts:
In a table in a paper titled Cerebral folate deficiency: Analytical tests and differential diagnosis, there's the following description of a mutation in a patient:

  Homozygous c.195C>G; (p.Cys65Trp)

I wonder what the letter c means here.


texts: advantages of shivering in cold environments

texts:
When we feel cold, our the muscle tries to generate heat by shivering and the brown adipose tissue tries to generate heat by non-shivering methods. The muscle generates heat but also spends energy on movement whereas the adipose tissue produces heat directly. This feels like muscle is not as efficient as BAT in generating heat.

What makes the muscle cause shivering? Isn't it sort of unnecessary movement which wastes energy which could otherwise have been used to directly produce heat?


texts: How does bacteriorhodopsin differ from the rhodopsin present in mammalian eyes?

texts:
In my high school textbook, it is written that they are similar. So, I was just curious to know about this.
Thank you.


texts: I often find booklice (aka psocids) in old paper notes I have in semi-storage. These pages of paper are intentionally left in dry conditions on my desk to avoid damage. However, if the psocids live and feed totally within these pages, how are they getting any water? How do the booklice avoid drying out and dying?


texts: Is this some kind of parasite crawling about in my yard?

texts: I've been living in Jamaica 25 years now and never seen something like this until recently they started popping up around my house at nights by the dozens.  They appear to be blackish purple or maybe just black (I think my light has something to do with it), but I recall seeing a grey one once and longest one I've seen so far is about 3 inches long.


texts: Why unripe, very young coconut fruits spoil in days, but the ones picked medium mature can keep months?

texts:
Coconut fruits can be collected at various stages of maturity.
Coconuts which are collected just when the flesh starts forming (about 5-6 months on-palm age), so they have very thin or almost no flesh, mostly just coconut water, they will spoil within just a few days in ambient temperature 30°C (86°F). Coconut water from such a fruit which stayed (in a n intact coconut) just a few days will start to taste off, and give stomach cramps.
As coconut mature on the palm, about 7-8 months of on-palm age, they grow more flesh and the flesh is becoming more firm, but not completely firm yet, while the outside of the coconut still remains more or less the same as the very young ones. Such coconuts will keep without spoiling much longer at the same temperature 30°C (86°F), provided the shell is intact, no cracks. Such coconuts are still considered young. I am not talking about fully mature coconuts, when the meat is completely hard and the outer shell starts to turn brown - this happens after about 10 months of on-palm age.
What biochemical difference is in the coconut water that prevent the medium-young (7-8 month) coconuts from spoiling as fast as the very young-picked ones?


texts: Why does the affinity of haemoglobin for oxygen increase at higher elevations?

texts:
Why does the affinity of haemoglobin for oxygen increase if an organism lives at a higher elevation where the oxygen pressure is lower?

Wouldn’t its affinity for oxygen decrease because the acidity of the body would increase with the lack of oxygen? The textbook said otherwise though and I don't understand.


texts:
People with Huntington's disease have HTT genes with more than 37 copies of CAG repeat. The risk of extra copies being generated is higher during sperm formation than during ovum formation. Why is it so?

Interesting fact: People with HD allele inherited from father develop symptoms earlier than if that allele is inherited from mother.


texts: umbrella term for microtiter plate, petri dish, cell culture flask etc

texts:
I'm looking for a term I can use in a software user interface that includes anything that may carry cell cultures or similar biological imaging samples (ie that may conceivably go into an automated microscope).

Since it's for a user interface, the term should be short and intuitive.  It should not depend on context.

Examples:

vessel, carrier, dish --- often used for what I mean, but not intuitive out of context.
cell culture carrier --- too long, also potentially too specific.


texts: How to write a stoichiometric matrix for a part of the Pentose phosphate pathway

texts:
maybe this is more bioengineering than biology but I didn't find any such group.

So I got the following photo:

And I was asked to do the following for the network inside the red area.
1) Write the stoichiometric matrix for the network
2) Draw a pathway map for the network
3) Draw primary metabolite connectivity maps
4) Write the mass balance equations for primary metabolites

I know that for the first one the columns are the reactions taking place and the lines are the "chemicals". Should the markings on the columns be the same as the numbers that are written on each reaction? (like "3.1.1.31")
Almost every reaction can go in both direction, is there anything that says which chemical should get minus and which one gets plus?
My attempt at the matrix was:

As for the pathway map, isn't that basically the photo is given?
And finally what would be a "primary metabolite" in this case?

All help and hints very well appreciated!


texts: What is one Botulinum toxin medical unit?

texts: How many Botulinum toxin molecules or grams are contained in one medical unit of Botox?


texts:
Spotted this beetle on Morfa Nefyn, a beach in North Wales, UK. The beach is a mixture of sand and stone, with large sandy cliff faces and rocky outcrops.

The beetle was about 3 to 5 mm or so long, running around on the rocks at the edge of a rock pool (not in the water though!), on a warm sunny day. It was moving are quickly, but not really fast, maybe around 1cm per second.

I've seen them on the beach before and sure I know what they were called but can't for the life of me remember.


texts: Is there a scientific explanation for male and female fragrance preferences?

texts:
The following is only anecdotal evidence, but in my experience it's very consistent.

When products have added fragrance (cosmetics, soap, air freshner, candles, etc), women often seem to enjoy the fragrance whereas men's reaction is normally something from indifference to outright revulsion.

I've tried googling this but the results are all about sexual attraction, which I'm not asking about.

One could speculate that this pattern is because the folks in marketing have worked out that adding fragrances will make women buy things and that as far as men are put off by fragrances, that doesn't have a net negative sales impact. But such theories don't answer the underlying question:

Why is there a difference in experience between men and women reacting to the same fragrances in the first place? Is there a "hard science" explanation for this phenomenon?


texts: Every RNA has an unique sequence. Since RNAse is an enzyme and substrates react to its active site in a lock-key mechanism, how is RNAse able to degrade any kind of RNA?


texts: I mean the immunity that covers only one body part or skin area after exposure to the infection but does not cover the whole organism.


texts:
Endorphins are among the brain chemicals known as neurotransmitters, which function to transmit electrical signals within the nervous system. Stress and pain are the two most common factors leading to the release of endorphins. I wanted to know if they are addictive, and found some contradicting answers:

  If people can get addicted to risky sports just for the thrills they
  provide, they can also get addicted to painful activities where
  endorphins provide relief, "despite the harm to self and/or others,"
  says Dr. Anna Lembke, chief of addiction medicine at Stanford
  University School of Medicine in an email interview. "For example,
  someone who compulsively cuts herself for the endorphin release is
  causing self-harm. Someone who compulsively runs, even to the point of
  causing musculoskeletal injury, is causing self-harm."

Source:
https://science.howstuffworks.com/life/inside-the-mind/human-brain/can-be-addicted-to-endorphins.htm

  In contrast to the opiate drugs, however, activation of the opiate receptors by the body's endorphins does not lead to addiction or dependence.

Source: https://www.medicinenet.com/endorphins_natural_pain_and_stress_fighters/views.htm#

If they are not, how can we explain the 'love' for pain in (this content might be sensitive for some of you) some people?


texts:
I've been looking into CAM plants - notably the snake plant which is native to West Africa.
Upon researching the CAM photosynthesis cycle, I've found it fascinating that the plant stores CO2 at night and photosynthesizes during the day. But I'm a little confused as to how oxygen is a byproduct of this reaction. There seems to be no images of the cycle where oxygen is involved in any of the diagrams I've seen.
There was one question somewhere online that explained it, but I was nowhere near smart enough to understand their technical language and so I didn't really get an answer.
So here's my question.
Does a CAM plant release oxygen during the day? If so, is there a specific ppm value or some other value that that is applicable to a snake plant or another similar plant that I can use to calculate the approximate amount of oxygen released?
Your help is  much appreciated.
Thanks!


texts: What happens if a non-diabetic receives an injection of insulin?

texts: If a person without diabetes or any diabetes-related issues receives an injection of insulin, what happens? Would the blood glucose level drop or does the body naturally compensate for the added insulin? What biological process occurs?


texts: Why are we able to differentiate between colored objects without the presence of light?

texts:
Rods help us to see during the dark.

We can see colour of the object when it reflects light.

But in a dark room(room of any color but the light is switched off and it is night),we still can differentiate between colored objects if we open our eyes for sometime.(although not very much clearly)

How the colors are seen when there is no light?

Do we see as the brain remembers their colour?


texts: Since the matter in the brain is recycled every few days how does consciousnesses work?

texts: Since parts of the brain are recycled every few days does that mean that materialistic theories of consciousness don't work?


texts: Is touching or inhaling 70% isopropyl alcohol dangerous to humans?

texts:
I bought 99% isopropyl alcohol and made 70% alcohol + 30% water in small spraying bottles as a disinfectant.

I also read that this solution is safe and recommended by Apple for cleaning iPhones.

My worry comes from reading on the 99% bottle how extremely dangerous it is to humans. Basically touching, inhaling and of course consuming it is very toxic.

On the other hand 70% alcohol solutions are found in most hand and surface sanitizers which are usable against COVID-19.

So my question is: how much should I be afraid when cleaning surfaces with my small 70% spray bottle? Since alcohol evaporates, I'd be naturally inhaling it, I mean where else could it go in the air? I'm also just spraying it on a wipe to clean my mobile, not using a rubber glove for that.

What are the health concerns when using such solution?


texts: Is one part of the day more prevalent then other when it comes to mammal animals mating? Is there an aggregating study that has been done to see if these living beings in nature mate mostly during day or night?


texts: If someone were to die on the moon, would their body decay?

texts:
I heard that the footprints of Neil Armstrong are still there, so I was wondering if someone were to die there, would they remain preserved, too?

If not how long would it take for them to decay?


texts: What labs/companies provide comparative genomic analysis?

texts: I’m looking for labs/companies that provide comparative genomic analysis between two different species, AND do so for the “paying” public.  I am looking to test a hypothesis regarding genetic expression and would appreciate any direction.  Thanks!


texts: can one be infected with Naegleria fowleri by taking Steam?

texts:
will Naegleria fowleri be present in the steam molecules.

Many people take steam from hot water to get relief from sinus.

I read somewhere that Naegleria fowleri gets killed over 70 C. So steam will also kill it?


texts:
What risks are associated with ultrasound/infrasound listening via bone conduction?

Would you risk yourself serious physical harm doing this?
What levels for these frequencies are safe to the human body?


texts:
Why are nitrogenous bases of DNA hydrophobic if they can hydrogen bond?

Is it that they are only relatively hydrophobic?

This forum explains it but does not give an example of the structure.


texts: How do detergents interfere with protein assays?

texts: This has been getting me stuck. I've tried to understand what a detergent would do in an assay, but I can't figure out whether it would affect the protein or the reagent (say, in a Bradford assay).


texts: Is cell cycle arrest needed for apoptosis to occur? I note that some of the factors that mediate cell cycle arrest induction (e.g. DNA damage) happen to be responsible for initiating apoptosis as well. However can apoptosis occur without first arresting the cell cycle?


texts: Why slow worm lost ability to walk in evolution/ecology perpective?

texts: Can  lost of legs for slow worm be considered as Batesian mimicry?


texts: How do nuclear membranes form during Telophase of Mitosis/Meiosis?

texts:
During Telophase, homologous chromosome pairs reach the poles of the cell with the help of microtubules. From there, nuclear membranes form around each new set of chromosomes.

My confusion originates from a single question: How did these nuclear membranes form around the chromosomes?


texts: Are there any exceptional cases in which a person with O negative blood group cannot donate?

texts: Are there any exceptional cases in which a person with O negative blood group cannot donate or any case in which compatibility might not be established between O negative an any other blood group?


texts:
NK cells are very effective in destroying circulating cancer cells before their extravasation into the organ, However they have only a minimal inhibiting effect on already established micrometastases.
Anyone knows why ?
Regards.


texts: Why does applying pressure to a venipuncture site prevent haematoma?

texts:
From what understand, when drawing blood, a phlebotomist puts pressure on the venipuncture site while withdrawing the needle to prevent a haematoma.

I'd like clarification;

How does this prevent a haematoma?
And why is it not necessary until withdrawal?
I assume it's not necessary, and counterproductive to apply pressure prior to withdrawal, besides complications or unusual procedures etc?

My best guess at a rough idea if what's happening is simply pressure restricts flow out of the vein, so slowing blood leaking into surrounding tissue, helping clotting? Or maybe it increases vein inner wall cell damage, releasing agents triggering faster clotting?

Thanks


texts:
As a medical student I have been taught that tendon sheaths are found predominantly in the wrists, hands and ankles. However, I learned recently that tenosynovitis often affect the biceps brachii. It is confusing me because this implies that the biceps' tendon also has a sheath.
Can someone tell me where exactly tendon sheats are found in humans ? Are they ubiquitous ?
Many thanks in advance.


texts:
I have very limited knowledge of how the human memory works as I think, at this time, most people do. However, I have been reading and some articles which say, and I quote the article just linked

  Memories are made by messenger RNA (mRNA) that encode β-actin protein.

Now, correct me if I'm wrong but proteins of any sort have mass. So, why following this rule of proteins being used to create the memory does our brain not grow in mass with each memory we create/ encode. And also, if our memories are encoded using proteins, why can neurodegenerative  (E.g. Alzheimer's) cannot be cured by artificial proteins in the same way we use insulin. I quote again,

  memories were merely out of reach

full article
Surely this means that, it is possible to, by using artificial proteins or possibly electrical stimuli we could recover memories. Or have I wandered off on a wrong track here? Am I correct? Or are my concepts of memory slightly wrong?