texts: Why do women mature (physically) earlier than men?

texts:
All sources I've read (the first page) states that the fact that women mature (in the sense of physical maturing) earlier than man is caused by the earlier selective prunning in brain. Though, this is an explanation just for the mechanism, not for the cause.

So what is the real evolutionary reason women mature earlier (though, probably slower) than men?


texts: Why do female humans invest more in parental care than male humans, from an evolutionary standpoint?

texts:
As the question title suggests, why do female humans invest more in parental care than male humans, from an evolutionary standpoint?

My guess is that the crux of this that males and females have different reproductive biology, but this by itself would not a very satisfying answer, due it not being very comprehensive.


texts: Mackerel evolutionary health affected by loss of predators?

texts:
I notice that Atlantic Mackerel (Scombrus scombrus) is endemically affected by parasites. In one study I read that the researchers found that over 70% of the mackerel sampled were infected with parasites.

Is there any evidence that the diseased state of the mackerel population is possibly due to loss of natural predation? The major predators of mackerel are tuna and cod, both heavily fished by humans. At one point cod was fished nearly to extinction and is still considered endangered. Since cod will typically catch the laggards and least fit of their prey fish, like mackerel, I would expect that over time this predation would tend to eliminate sick or unfit fish. Without this natural predator, perhaps it is leading to sickly conditions in mackerel?

Is there any basis for this thinking?


texts: Do camels have nucleated RBCs or enucleated RBCs?

texts:
Most mammals have enucleated RBCs as an adaptation to facilitate the transport of oxygen. My text says that camels and llamas are exceptions to these.

I was wondering why they are exceptions, and the Google search results are confusing. Some sites say that camels have nucleated RBCs to facilitate cell division. Some others state that camels, like all other mammals possess enucleated but different shaped RBCs. So, which is correct?

The links:https://www.quora.com/Why-do-camels-have-nucleated-red-blood-cells
https://in.answers.yahoo.com/question/index?qid=20070702070352AAkfspZ


texts:
I read quite a bit online about omega 3 deficiency. How is this actually determined - that is, what happens in the lab to determine this ?
n-3 fatty acids have roles in many different human tissues, so does the definition of sufficiency vary depending upon which tissue is being studied ?


texts: Is carbon dioxide dissolved in plasma same as carbonic acid?

texts:
Carbon dioxide is transported through blood via 3 methods :
1. Dissolved in plasma 2. As bicarbonate  ion 3.through RBCs. The carbondioxide when transported as bicarbonate ion i.e HCO3- and H+.  What i dont understand is that dissolved carbon dioxide in plasma should also yield H2CO3,  so is writing co2(aq)  the same thing as writing H2CO3? Further shouldnt this carbonic acid also dissociate and form bicarbonate ion and proton? Doesn't this make both the processes equivalent?
What i found out is that H2CO3 has a low   ionisation constant of the order 10-4, is this tbe reason why they are separate events? Implying that carbonic anhydrase  catalyses the formation of bicarbonate ion while some part of H2CO3 is not ionised and that is what refers to co2(aq)


texts: Can a person die from over exposure to rain?

texts:
Is it possible to die from being over exposed to rain? For example, if outside for a long amount of time (days) in a continuous storm?

I searched online but didn't find anything immediately. To me, maybe a really long exposure to rain (water) would cause skin tissue issues, which might then have potentially more serious effects on other body organs/systems.


texts: If a person is infected with an RNA virus what percentage of the RNA in the blood of the person contains RNA of the virus?

texts:
Karius uses DNA sequencing of everything that's contained in a sample to detect all bacteria and DNA-viruses in the sample. Given the way that costs of sequencing are falling this approach seems to be the future of detecting bacteria based infections.

It would be great if the same approach would also work for RNA-based viruses. For it to work it would of course be necessary that there's enough RNA of the virus in comparison to the other RNA.

How much virus RNA is there in a person who's infected by an RNA virus in comparison to the other RNA?


texts: Why is there disagreement on the number of surfaces of the human heart?

texts:
I am finding that some state that there are 5 and some that say that there are 3.

For example, "Cardiology: An Integrated Approach" that was published in 2018 states that

  There are 3 surfaces of the heart: anterior, inferior, and posterior

Radiopedia, Teach Me Anatomy, and others state that there are 5.

Why is there this difference? What exactly is a surface?


texts:
How can a mutualism between two species arise? I have thinking about this for a while and I have come up with the following points
1.If mutualism gives one specie a competitive edge over its competitors then it could arise. Suppose you are being really pounded by your competitors and there is now way you can survive except if you give in to mutualism, even if it means "selling your soul".
2.The benefits received from the partner species outweighs the costs involved in helping it out.

I cannot think of any more examples. Please suggest a few; also point out if there are flaws in my reasoning.


texts: Why Is Action Potential Propagation Not Described by Telegrapher's But Cable Equation?

texts: In modelling the propagation of action potential in an axon, why is the partial differential equation the cable equation rather than the telegrapher's equation? The difference between the two is that the former does not have inductance while the latter has. Does an axon not have inductance whether it is myelinated or unmyelinated? This is related to my previous question. There the only answer I obtained attributes this choice not to experimental evidence but the deficiency on the part of biologists in mathematical sophistication in dealing with the complication of electromagnetism arising from including inductance.


texts: It is from Bangladesh. Is it hawk moth? I am not sure. Please help.


texts: Examples of things that are undefined in terms of living and non-living

texts:
I'm putting together a class on basic biology for kids and I will discuss living and non-living.
I'm looking for examples of things which are undefined in terms of living and non-living, if there are any.
People expect viruses to be alive but they are defined as non-living. Other examples of things that go against intuition are also welcome. Or things which were once classified one way and later redefined.
I couldn't find anything online.


texts: Is EGF-mediated proliferation symmetric?

texts:
It's known that the MAPK signaling cascade (say, ERK) is downstream of EGFR in epithelial cells, and that EGFR activation can cause proliferation in some cell types in some situations. My question is the following: if an epithelial cell with active EGFR (and hence active ERK activity) divides, will the two daughter cells have the same amount of ERK activity as the parent, both have half as much ERK activity as the parent, or divide asymmetrically? I suppose ERK activity should be defined here as ERK phosphorylation... though I would certainly welcome better definitions!

If you need better context, I would be considering wound healing of mammalian epidermal skin. There are plenty of sources suggesting that in response to  a wound puncture, EGF is released and stimulates proliferation.

Thank you!


texts: How is the concept of species defined in asexual organisms?

texts: In asexual organisms such as bacteria, archea and some fungi, as well as in some plants where asexual reproduction is the only reproductive strategy, how can we be unambiguous in defining if an organism belong to a different species from another or not?


texts: What makes the hepatic portal vein unique?, is it because it begins and ends with capillaries or because it carries digested food.


texts: I took a few photos at the Aviary of Hong Kong Park. The photos included some pheasants, and the below shows 4 of them. What species are they? I am not sure if 1, 2, 4 are actually the same species or not. Unfortunately on the official website http://www.lcsd.gov.hk/en/parks/hkp/birds_collection.php they are not included in the bird list, perhaps they are newly introduced.


texts: Biological term for close species rivalry

texts: Is there any phenomenon/force in biology when two very close species fiercely fight each other (as a sign of a strong tendency to deepen the difference between species)? If there is, what's the name of the phenomenon or any similar phenomenon? (Question from a layman in biology, thanks for an answer.)


texts: Are there parasitoids of mosquitoes ? (other than nematodes)

texts:
Outside of nematodes, are there any examples of organisms that are parasitoids of mosquitoes ?

I could not find any example in literature so far. I'm notably interested to know if the most known mosquito genera (Aedes, Anopheles, Culex...) have already been described to be parasitized by other insects (e. g. parasitoid wasps), and if this is a common phenomenon in nature.


texts: Are we capable to generate sounds of animals to the point that they mistakenly recognize it as members of their species?

texts: From Animal language (Wikipedia), there are many evidences that we can communicate with animals, at least to baboons and dolphins. There is a case that fish moving away when hearing a record of whale sounds, however no examples mentions about the sound we actually make to communicate with them. We can even dog whistle, but this doesn't mean the dogs thinks that there is another dog. In my opinion, the answer is yes, since once we can capture the sound with spectrograms we can ultimately generate it. Is there any research on this?


texts: How are antibiotic resistant bacterial infections treated?

texts: For example, how are infections of antibiotic resistant strains of MRSA, Streptococcus, or Gonorrhea treated?


texts:
The concept of water potential in plants tries (and succeeds) to explain various movement and transports in plants. I have learnt that it can be though of being composed of various components like the solute (osmotic) potential, Matric potential, gravitational potential and the pressure potential. I know how to quantitatively determine the osmotic pressure and have worked with the chemical potential of water in solution and pure state. Can someone help me develop an intuitive understanding of all these components quantitatively? I am comfortable with basic thermodynamic treatments of chemical potential and already have an intuition of the osmotic component. Here is the basic definition regarding water potential. (Since this pdf is quite old, I am not sure whether the same definitions operate or rather are used now.)

EDIT:- As an example, we can derive the lowering of chemical potential of pure water on addition of solute and for the ideal case, the lowering turns out to be $RTln(X_a)$ (where $x_a$ is the mole-fraction of solute, $R$ is the gas constant and $T$ the absolute temperature) and this is defined as the osmotic potential or the solute potential. Next, the gravimetric component. We can intuitively understand that the water must flow from higher gravitational potential to lower and hence flow downwards. But I want to understand how can we assign a quantitative basis to our arguments in terms of chemical potential for differenf heights. Same way, how can we ascribe a mathematical (or chemical) basis to all the components of water potential including the turgor pressure and the matric components.


texts: Why are tree rings the same if rainfall is different from place to place?

texts:
I have looked at data from rain gauges and usually the rainfall levels are very different from place to even. Even in adjoining towns or townships the rainfall can exhibit much different patterns.

Nevertheless, all the trees in an area tend to show the same ring patterns. Why is this?


texts: What is the population limit that makes consanguinity an issue?

texts:
A recent incident brought in the news one of the last uncontacted people - the Sentinelese:

  the Sentinelese appear to have consistently refused any interaction
  with the outside world.

  There is significant uncertainty as to the group's size, with
  estimates ranging between 40 and 500 individual

If I understood correctly, the Sentinelese have a rather small population for dozens if not hundreds of generations and I am wondering if consanguinity is not issue (e.g. serious childhood effects) for them.

Question: What is the population limit (lower bound) that makes consanguinity an issue?


texts:
I want to understand how Turner syndrome - monosomy X - occurs at the molecular level. The NIH mentions that there are cases of both complete monosomy and of mosaicism.

I’m particularly interested in the monosomy case, as this really confuses me. How does a fertilized egg end up with only one sex chromosome (an X, in this case)? Is an empty egg fertilized by an X-bearing sperm? Is an X-bearing egg fertilized by an empty sperm?

The case of the mosaicism is easier to imagine - say through X chromosome nondisjunction at a very early point in some cells of the embryo. NB: unsure this is actually how mosaic monosomy X happens.

I haven't found a source that doesn't begin from the point at which monosomy has already occurred.

How do things get to that point? Where and how is a sex chromosome lost, such that a human can develop with only the one?

Thanks so much for any pointers!


texts: Why are amino acids in biology homochiral?

texts: Why are nearly all amino acids in organisms left-handed (exception is glycine which has no isomer) when abiotic samples typical have an even mix of left- and right-handed molecules?


texts:
Many have heard about the fabled "immortal" jellyfish, Turritopsis dohrnii, which doesn't die from aging (senescence) and can revert the aging process indefinitely. It is rather remarkable that only one, or very few species show this type of behavior.

I wonder if at some earlier point in evolution, when life was predominantly simpler and sea based, there were more species with this feature, but this "immortality" caused overpopulation and/or didn't allow for proper action of natural selection, meaning that "immortal" species didn't evolve much and got wiped out almost entirely by whatever phenomenon.

In this scenario, aging and dying from old age would be an important evolutionary trait which would allow for populations to maintain reasonable sizes and would allow for natural selection to impart changes.

I was wondering how plausible all of this is, since I'm not an expert in the area and know little about the appropriate technical concepts behind these things.


texts: What is this insect in a cocoon climbing a web?

texts:
I found this thing hanging from the framework of my garage yesterday:

The size of the object in the picture was about .75 inches tall by maybe a quarter inch wide. This was taken yesterday in a suburb of Jacksonville, Florida, US in late evening (8:30 pm?).

He was (apparently) using his mouth-parts to draw in what appeared to be a strand of spiderweb, and in about 10 minutes had drawn himself upward, towards the top of the garage framework, a total distance of about two feet.

An additional question would be what is that he's in, a cocoon? a piece of bark or something being used like a hermit crab uses a scavenged shell?

Any help would be appreciated!


texts:
I am aware that the average DNA contribution from each grandparent is 25%, while the possible range is 0%-50%.  I found a source citing 18%-32% as the "normal" range but this was undefined.  I assume it must be referring to a percentile based on the distribution in a Gaussian curve.

After searching in vain for a chart showing "normal" ranges for each level of consanguinity (sibling, grandparent/aunt, great-grandparent/cousin etc.), I started doing the calculations myself on an Excel spreadsheet... and soon went back to searching.  Surely this information is available somewhere, and there must be generally accepted norms.  The math formulas are well established.

Where should I look to find the results summarized in a compact format?

I want to first know, essentially, the statistical results of flipping 23 identical immutable coins to represent the various generational probabilities.  The facts that the chromosomes are not identical, and that recombination is more likely at certain loci on certain chromosomes, are to be considered later as adjustments to the non-biological math.

I will pursue a statistical answer elsewhere if I can get the "biological" answer as to what percentile is accepted as the "normal" range.  (The 25% average for grandparents has a vanishingly small probability of actually occurring, as it would require enough recombination to equal an inheritance of 11.5 chromosomes from each grandparent.)


texts:
I encountered the term, “rapidly labeled RNA”, in the article: Rapidly labeled HeLa cell nuclear RNA. I. Identification by zone sedimentation of a heterogeneous fraction separate from ribosomal precursor RNA. (1966).
I would appreciate it if someone could explain to me what it means or implies.


texts: Answer the questions in one word with help of clues and images given

texts:
Name the things associated with Antonie Van Leeuwenhoek - (6 pictures are given for help and four of them are associated with these clues)

a)Leeuwenhoek was the first to describe these and hence called the "Father of Microbiology"

b)He found many of these (rotifers) in the rainwater collected in ditches and canals

c)Leeuwenhoek was the first to describe plant vessels in this cross section of an ash tree

d)Leeuwenhoek used this to observe microorganisms.


texts: What is a good miniprep protocol for the class room?

texts:
I'm trying to find a good protocol for plasmid minipreps and I'm looking at 3 preps I've found:

Using phenol/chloroform

extract with phenol:chloroform:isoamylalcohol,
isopropanol precipitation, 12,000g spin down,
rinse with cold 70% ethanol.

Using lysozyme

lyse with lysozyme,
remove pellet,
isopropanol precipitation,
wash with cold 80% ethanol.

Using alkaline lysis

open cells with 80% glucose in EDTA buffer,
add SDS and NaOH,
pellet protein/membrane with acetic acid/acetate,
ispropanol precipitation,
wash with cold 70% ethanol.

They all differ in how to break open the cells and separate plasmids from the rest of the cell -- quite a bit.  Can anyone help me figure out which protocol is best here?


texts: Are rods/cones rejuvenated periodically?

texts:
Pretty much what the title states.

Some cells/structures in the human body undergo rejuvenation periodically by flushing away older cells and growth of new ones.
E.g Skin, Blood

Does this (for want of a better word) 'rejuvenation' apply to Rods/Cones within the eye too? If so, how are the old cells flushed out - or do the old cells become part of the local humour?


texts:
I was wondering, after decades of research what we do not know about Cancer yet as in what unanswered questions are still puzzling biologists about cancer?

I have read that cancer research, in its modern form, is a quest for biological immortality. Does this hold any truth?


texts:
The retina is light sensor, which converts light to an electrical signal.  LEDs can both emit and receive light. Similarly, is it possible to apply electricity to retina to generate light?

Simply put, in theory, can humans emit electromagnetic waves from their eyes?


texts: What is the scientific name of this flying insect?

texts:
It looks like some relative of dragon fly.

To give an idea about its size I picked it by its wings

It had quite a flexible abdomen

I set it free after clicking the pics. I live in central India (If that matters)


texts: Is there a term for the group of individual organisms whose matrilineally descended female ancestors all share a common ancestor?

texts: A group of individual organisms that are all descended from a common ancestor is a clade. Is there a term for a group of individuals whose matrilineally descended ancestors (mothers, maternal grandmothers, maternal grandmothers' mothers, etc.) are all descended from a common ancestor?


texts: Can anyone help me identify what type of horns these are?

texts:
I picked these up at an estate sale a few years ago and now need to identify them for shipping purposes.

They are 29x18x10.5 inches in size.

A friend who works in antiques believes the are over 100 years old based on the wood they are attached to and thinks they belong to some kind of ram. That's all the information I have on them.

Any help would be appreciated.

Thank you.


texts: Insect identification - is it a bed bug?

texts:
We were on holiday and got bitten by (most probably) bed bugs. We then carried them home, and I also saw a typical one: 4mm, flat, round, black. I thought it was pretty clear we had bed bugs. I smashed one:

Currently (2 weeks later) we have a lot of small insects in the house, like shown in the picture. But they don't really seem like bed bugs, do they? The big ones look like bed bugs, but the small ones don't?

What is it? It's around 2mm (others are much smaller, very tiny, less than 1mm). They can jump (or run really fast) 2cm if I try to squash them with a finger.

Update:

The small one is very similar to a psocid?!

Update 2:

They have wings.. I think they're psocids.
What I also realized, I probably have two different larves. I take some more probes..


texts: What mechanism prevent Colchicum Autumnale from being affected by Colchicine

texts: Colchicine is a chemical usually used to cause polyploidy mutant by inhibiting chromosome segregation. It is synthesized in the Colchicum Autumnale. But what mechanism prevent C. Autumnale from being affected by the Colchicine?


texts: What is Hamilton's rule for multiple generations?

texts: What is Hamilton's rule as it applies to multiple generations?  Is it that the lineage success given up by the actor must be exceeded by the lineage success acquired times the relatedness between actor and acquirers?  How is this represented?


texts:
A colleague of mine who mainly focuses on clinical chiropractic work claimed recently in a book he wrote that muscles in the pelvic floor have "elastic recoil."

What he means by this is that a muscle behaves like a spring and, upon relaxation, releases potential energy somehow.

I am highly skeptical of this and want to verify if this is true or not.

When a muscle contracts, does it store potential energy like a spring that is released upon relaxation?


texts: When restriction enzymes jaggedly cut double stranded DNA it results in so called sticky ends. What is the substance that makes the DNA sticky?


texts: How is Pseudomonas aeruginosa diagnosed?

texts: I know that P. aeruginosa is cultured on an agar plate, but which media or assays make it distinct from other Gram-negative bacteria?


texts: What are the differences between how glucagon and cortisol work to increase blood sugar?

texts: As I understand, both cortisol and glucagon cause an increase in blood sugar concentrations. However I don't understand how they work differently or why they work separately. I would be very grateful if someone could explain the seperate roles and functions of these two hormones and also the different effects that they have (I believe cortisol also has something to do with promoting lypogenesis in adipose tissue at the trunk of the body and lypolysis at the extremities).


texts: Why are Lymphatic trunks part of the Cardiovascular system?

texts:
According to Wikipedia the Terminologia Anatomica (international anatomy standard) the lymphatic trunks are part of the cardiovascular system instead of the lymphoid system.

Why did they make that choice?


texts: What are the obstacles to modifying an algae to secrete fuel?

texts:
I've been reading a bit about algae fuel. It sounds like people did some work and then decided it was too difficult. This link mentions Exxon's work:

https://en.wikipedia.org/wiki/Algae_fuel#Commercial_Viability

And this next link shows the ex-CEO of Exxon talking about how they wanted an algae genetically modified to secrete oil, so they didn't have to kill and harvest it. He then says they encountered a low-level problem with the basic science, but doesn't elaborate.

https://youtu.be/vGv0R3zJ3cc?t=4m26s

Anyone know what that problem was?


texts: What are the distinct neurochemical components of sexual pleasure?

texts:
Sexual activity is usually described as pleasurable.

What neurochemical systems does sex activate? Does the presence or absence of a partner make a difference -- say, in the activation of the oxytocin system?

Undoubtedly, sexual activity is salient, and so it surely involves dopamine. (Salient activities, whether painful or pleasurable, activate the dopaminergic system.)

What about these systems:

adrenergic
gabaergic
cannabinoid
nicotinic
opioid
serotonergic
cholinergic
glycinergic
histaminergic
glutaminergic


texts: Can Two Opposite Running Action Potential Cross Each Other without Annihilation in One Axon

texts:
Can two opposite travelling action potential cross each other annihilation in an axon?
My answer would be affirmative. If the propagation mechanism is linear as described by https://en.wikipedia.org/wiki/Cable_theory or even https://en.wikipedia.org/wiki/Telegrapher%27s_equations with approximately constant coefficients, the waves are then linearly additive and each signal should propagate unperturbed. The refractory period on each end of the axon can not possibly prevent the other end from being excited at the same time since the signal has not arrived yet.
This question is inspired by the question Can a single axon propagate multiple simultaneous action potentials?


texts: What purpose is served by the pits and pores in xylem and phloem cells? I cant find what purpose that these components serve in the vascular tissues in plants


texts: Is there any way a human could whistle and be unable to speak?

texts:
Is there any situation anatomically, where a human could understand the speech of others perfectly, without any capabilities of speech themselves, but would retain the ability to whistle with a tune?

I was led to believe that the larynx is the most important thing for creating the sounds in speech, however I don't know if a damaged larynx would necessarily not allow someone to speak.

I would suggest someone who has no tongue cannot speak coherently, however I would imagine that the tongue is instrumental (pardon the pun) in creating a range of sounds whilst whistling.

Is there perhaps a part of the brain that could be affected in order to stop someone speaking? Or would this also mean the person could not understand speech either?


texts:
At the molecular level, electrical current across cell membranes ﬂows through three unique classes of integral membrane proteins (see Chapter 2): ion channels, electrogenic ion transporters, and electrogenic ion pumps.1

later it is said:

One class of electrogenic transporters includes the adenosine triphosphate (ATP)–dependent ion pumps.2

Is there any fundamental difference between "electrogenic" ion transporter and "electrogenic" ion pump, considering the fact that denosine triphosphate (ATP)–dependent ion pumps are also included in the former?

My attempt:
From this site ,Secondary active transporters are electrogenic, so if I consider those as electrogenic ion transporters , then also iam still confused why sodium potassium pump is in the category of ion transporter but not in ion pump.


texts:
I am a student of Physiology, and I have ended up a bit confused after what I've read today regarding events during a threshold potential. So, while cells are in their resting membrane potential, the inward current of sodium is equal and opposite to the outward current of potassium. The same is true about the threshold potential.

When the threshold potential is reached, the inward sodium current is exactly equal and opposite to the outward potassium current. If this is true, why is there a change in the voltage of the membrane, let's say from -70 mV to -55 mV? I mean, both of the currents are equal and opposite and therefore there shouldn't be any change in the resting potential of the membrane.


texts: What indices can we use to describe fitness landscapes?

texts:
We usually talk of smooth or rugged fitness landscape.

Are there any (standard) indices to measure the "structure" of fitness landscapes?

For example, one might consider the mean epistatic interactions (over all possible combination of loci)


texts: Does the change in eye color (melanin concentration) affect the iris pattern?

texts:
In cases of acquired heterochromia, is there a quantifiable change in the iris pattern; the clefts , furrows, etc.
If yes, what changes are observed?
And if no, are there any diseases or acquired conditions that cause a change in iris patterns?


texts: Does anyone use bootstrapping to report mass gain during experiment?

texts:
When performing an experiment to report gain of body mass in an experiment, do any of you know of a paper whose authors have used a bootstrap to improve their confidence intervals?

I have a n = 10 per group for a total of 6 groups, measuring whole body mass on a weekly basis in small animal models of a disease. Experimental design is essentially treatment by the use of a drug, over a period of ten weeks, and analysis of the final gain of body weight

(essentially think of a google search term as bootstrap, body mass, mouse)


texts: Convert flux value in nmol/min/mg protein to nmol/min/cell?

texts:
This is a question about unit conversion. I found an experimental measurement of the saturation uptake of glucose in yeast:
$$V_\textrm{max} \approx 650 \textrm{nmol}/\textrm{min}/\textrm{mg protein}$$
See Table III of Diderich et al. (1999)*. Actually the paper reports a range of measurements, I just picked an intermediate value.

Table III
Maximum velocity (nmol·min−1. mg protein−1) and Michaelis constant (mm)
of glucose transport by cells grown in aerobic glucose-limited
chemostats at various dilution rates and in batch culture on glucose

I want to convert this to nmol/min/cell, that is, to units of flux per individual cell.
These are my questions:

What exactly is the meaning of the units reported?
It wasn't very clear to me after reading the paper, so I suppose these are standard units. I presume that "mg protein" refers either to the milligrams of transporter protein, or to the total cellular protein content, but I don't know which.
If that's the case, what's the advantage of these units instead of
grams of dry weight (which I think are more common)?
Finally, how can I convert this to flux per cell?

* Diderich, Jasper A., et al. "Glucose uptake kinetics and transcription of HXTgenes in chemostat cultures of Saccharomyces cerevisiae." Journal of Biological Chemistry 274.22 (1999): 15350-15359.


texts: Why does double vision when drinking happen?

texts:
Why do you see double sometimes when you're drunk?  Its weird because it seems to happen more when you try to focus.

Try to look at something when you're drinking and it barely seems to double up
Try to focus on it more than just immediately, and slowly the image seems to separate
Refocusing on new object seems to re-focus and lets you not see double

Why does this happen?

Edit:
http://www.esquire.com/news-politics/q-and-a/a5711/double-vision-causes-0509/ This seems to imply an inability to focus, however, if I try to refocus on a new object it works out


texts: Is it possible to purify antigens from a vaccine and to separate them from the adjuvant?

texts: I need to separate the antigens from several vaccines in order to use them for coating microplates to run an indirect ELISA. I at least need to remove the adjuvant from the vaccines. Is this possible to do and if yes, how do I go about it?


texts: Why is darker skin a better defense against sun than lighter skin?

texts:
We know from physics that the colour of something comes from the light it reflects.

Dark/Black objects absorb most light while light/white objects reflect most light.

Sunburn is the absorbance of too much light and is bad for your skin's health suggesting that absorbance of light is bad for you.

So why is darker skin better than lighter skin for high sun intesity living conditions? Logically darker skin should absorb more light (and so energy) while lighter skin should reflect most light (and energy).


texts: If a trait does not appear to be advantageous to organism, why does the organism have it?

texts: Why do organisms have some traits that do not appear to have any evolutionary advantage?


texts: Is it possible to identify this chrysalis?

texts:
At least I believe it's a chrysalis. I found it hanging from my gate the other day.

I'm in Western Arkansas:

More photos here


texts: Proline Iminopeptidase v Proline Aminopeptidase

texts:
We're an undergraduate independent research team and we are having trouble purchasing commercial proline iminopeptidase as it is unavailable on Sigma Aldrich and very expensive on other websites. We need to test that this peptidase will cut a series of tripeptides we are synthesizing in e coli.

Could we purchase proline aminopeptidase instead of proline iminopeptidase; will the peptidase function the same way?

This paper says that they are the same, but this paper says that they are different. Does anyone have any experience with this commercial peptidase?


texts: What is the best way to clean immersion oil from the microscope lens?

texts:
My job is to photograph mushroom spores at x100 using immersion oil.

What is the best practice for cleaning the oil from the lens?

Right now I am just wiping it with a cotton swab.


texts: How can we decide at which level does natural selection apply?

texts:
Here is a passage from The Selfish Gene

  If selection goes on between groups within species, and between species, why should it not also go on between larger groupings? Species are grouped into genera, genera into orders and orders into classes. Lions and antelopes are both members of class Mammalia, as are we. Should we then not expect lions to refrain from killing antelopes, 'for the good of the mammals'? Surely they should hunt birds or reptiles instead, in order to prevent the extinction of the class. But then, what of the need to perpetuate the whole phylum of vertebrates?

So shouldn't it eat the other animals? Also in the next line, it says about vertebrates that since reptiles and birds are vertebrates, the lion should go for invertebrates.

It sounds illogical, but what stops lion from eating his "relatives", or from sparing a deer? And till what extent is the term "relatives" valid?

Is the question is too broad, please give a source where I can get an answer.


texts: how can we identify the novel protein amino acid sequence and function?

texts:
if there is a novel protein, how would you know the amino acid sequence and  how would you determine the number of subunits and the function of that protein?

Specifically what molecular techniques we can use to identify the novel protein?

Basically, this is a question asked during a biochemistry interview? It will be helpful, if someone just clarify it


texts: Bright green caterpillar with long white stripes, few hairs, no extensions, possibly Noctuidae

texts:
Our herbs had strange holes, and we found eight of these caterpillars to be the reason. They were mainly underneath the leafs and measured about 5 cm in length.

We collected them from the herbs, put them in boxes and also fed them (slightly rusty) crisphead lettuce, which they seemed to like just as well.

We tried to identify them, and our best guess was some sort of Noctuidae, possibly Ctenoplusia limbirena. We're located in central Germany.

When disturbed, they froze for several seconds, then slowly began to move (and eat) again. When picked up, they sometimes spit a few drops of green fluid at their attacker.

They ate "a lot" for a few days - and pooped just as much. I cleaned their box twice a day, but as you can see, they were quick to fill it up again. (I hope you don't mind the picture - at least it did not smell at all.)

Now, their behavior changed, and they folded leaves, attaching it with strings to stay in place, and hide in there - I suppose they're about to become pupas.

I would be interested in what species they are, and if they are dangerous to humans. We've always washed hands after contact and avoided touching their poo, though they most viciously attacked my girlfriend's finger with green spit (she survived without any damage).

Further, how can we help them advance to become winged? Is it sufficient to just leave them alone, or should we add more leafs or sticks to their box?

Finally, I was told they would practice cannibalism if food supply were too low - is this true? I would have thought their stomachs are specialized to leaves exclusively.

Edit: Not even a week later, they hatched, and I took some photos before setting them free:


texts: Why do people say that trans fatty acids are bad for your health?

texts:
I've heard from several sources that trans FAs are bad for you and their consumption will lead to cardiac problems, and that they are indigestible.
But I also learned from biochemistry that they are digestible. What is the reason for this, or is it true at all?


texts:
Is there a good book that explains operons: lac operon and trp operon in details.

I was reading  the functioning of the trp repressor protein from 'Principles of genetics-by Snustard and Simmons',they have mentioned that the binding of the repressor-corepressor complex to O$_t$$_r$$_p$ prevents the transcription of the structural genes. But they don't explain how.

Khan academy says that the repressor-corepressor complex physically comes in the way of the RNA polymerase. They have used this diagram below which shows that the large RNA polymerase cannot bind to the promoter site due to steric hindrance.

I'm looking for a more authentic source to study exactly how this RNA polymerase is being prevented from transcribing the DNA in both the operons.


texts: Nicotine levels in non fruit/edible parts of plants (that are not tobacco)

texts:
I am an ex smoker who now vapes (uses e-cigs). Various authorities are equating vaping with smoking by calling it a 'tobacco product' - which is in a sense true given that the majority of nicotine sold is extracted from the leaves of tobacco. I am interested in the practicality (or otherwise) of extracting nicotine from other botanical sources.

Of course, it is not just tobacco that contains nicotine, it is common in other plants of the nightshade family, as suggested by The Nicotine Content of Common Vegetables & Nicotine: Occurrence and biosynthesis. The second source notes:

  Nicotine is a natural product of tobacco, occurring in the leaves in a range of 0.5 to 7.5% depending on variety.[84] Nicotine also naturally occurs in smaller amounts in plants from the family Solanaceae (such as potatoes, tomatoes, and eggplant).[85]

Reference 85 points back to the first link, which shows this table.

But looking at the numbers, it seems unlikely. At even .5%, the 'low nicotine' tobacco leaf comes in at 5 mg/g, which is 5,000,000 ng/g - around 50,000 times more concentrated than eggplant. In fact, here is a graph of the log10 value (2 is ten times larger than 1) of each.

On the other hand, the ability of a plant to produce nicotine is retained and handed down to ancestors because nicotine is a pesticide that ..discourages insects from eating the plant, and larger herbivores will also get sick if they eat too much of it. Logically, levels of nicotine would be higher in the leaves and stems of a plant than in the fruits/food that we & animals are more interested in eating. That again makes sense, since most fruits are 'designed' to be put through the stomach of a larger animal as part of the process of regeneration.

That logic seems to be borne out by the levels of nicotine in tomatoes, that start around 40 ng/g in green tomatoes, but end up at just over 4 ng/g in ripe tomatoes (not sure what's going on with that 'pureed tomato' level of over 50 ng!). The drop suggests to me that's the plant's way of preventing consumption while the fruits are still developing, but making them safe(r) to eat once ripe.

But what about the nicotine content in the leaves of those plants? Logically they might have a higher nicotine content. Does anyone know of studies of the levels of nicotine in the other parts of plants of the nightshade family?


texts: Double Digestion with Restriction Enzymes Using Different Buffers

texts: I am currently working on preparing a 9 kb sequence of DNA for restriction digestion into the pBAD30 expression vector. There are very few restriction enzymes that do not have a restriction site located on my insert, and since I am using 2 restriction enzymes in my digestion, I had little choice in choosing my restriction enzymes. The only two restriction enzymes that will work for me are Xmal and KpnI. XmaI uses CutSmart buffer while KpnI uses NEB buffer. The efficiency of XmaI in CutSmart buffer is 100% while the efficiency of KpnI in CutSmart buffer is 50%. Would it be easier to perform a double digestion using CutSmart buffer and 2x KpnI than to perform two consecutive digestions?


texts: Why do Arctic predators accumulate vitamin A?

texts:
Top predators in the Arctic are known to accumulate vitamin A, often to levels that are toxic for human consumption.  A 2012 study by Senoo, Imai, et al. found that the livers of several predator species in the Arctic showed much higher levels of vitamin A than other Arctic species or closely related continental species, with no symptoms of hypervitaminosis A.

Why is it that these species accumulate vitamin A?  Does this have something to do with the food sources available in the Arctic as opposed to the mainland?  Or are there physiological reasons why Arctic predators would tend to accumulate vitamin A rather than breaking it down or otherwise eliminating it?

References:

Senoo, Haruki; Imai, Katsuyuki; Mezaki, Yoshihiro; Miura, Mitsutaka; Morii, Mayako; Fujiwara, Mutsunori; Blomhoff, Rune (2012). "Accumulation of vitamin A in the hepatic stellate cell of arctic top predators". Anatomical Record 295 (10): 1660–8. doi:10.1002/ar.22555. PMID 22907891.


texts: What proportion of the people who lived 1000 years ago have genetic descendants alive today?

texts:
For context, I've been wondering about this for a paper I'm writing (in philosophy). Really, I want to figure out the chances that someone alive today will end up still having descendants 1000 years in the future. But people from 1000 years ago should be a good approximation.

So, any ideas? And are there any published papers which talk about this?


texts:
I am physicist and have recently heard about DNA computing. I want to work in this area.
I want your ideas on a "feasible but new project" (maximum time I can put on the project: 6 Months ), I can work on.
(I have already heard about songs, image storage on DNA and don't want to repeat the same process for some other song or image).


texts: If longer wavelength color is perceived faster by human, what about non-spectral color (black)?

texts:
Related to human vision, I read the hypothesis about how longer-wavelength color is perceived faster by human eye than shorter-wavelength color source : A Brief Classification of Colour Illusions. But what if the other color is a non-spectral color like, black ? Black is achromatic color, it's the absence of colors and has no wavelength. Does this perception hypothesis still apply ?

Because I've been doing a color comparison by putting a layer of colors on top of each other. In this case I tried with black - green (~549nm) and black - yellow (~570nm), and it seems like black is always dominant against other colors. But I can't find any scientific reference for this. The closest I found is the hypothesis I mentioned before. Any suggestion ?


texts: Question about phylogenies and DNA sequencing

texts:
I'm reading this web page which talks about phylogenies and DNA sequencing:

https://bioinf.comav.upv.es/courses/biotech3/theory/phylogeny.html

A certain sentence says, "If we consider dolphins and sharks to be closely related because they share a similar shape we would be mistaken."

If we were to take the DNA sequence of the dolphins and sharks and compare the genes encoding for shape, wouldn't they be very similar? Wouldn't we then be able to conclude that dolphins and sharks are similar?

Or is the workaround that we would examine the entire genome, i.e. the entire DNA sequence, to see if that's the only similarity they have?


texts: Genes that exist in old Affymetrix platform but not in the newer one

texts:
I am using two gene expression datasets from an Affy U95Av2 platform and an Affy U133 Plus 2.0 platform. When I map the Affy probe names to HUGO gene names, there are thousands of genes which exist in the newer Affy U133 Plus 2.0 dataset while not in the old Affy U95Av2 dataset, which is something expected. But there are also 97 genes which exist in the old Affy U95Av2 platform while not in Affy U133 Plus 2.0 platform. I would not expect that because Affy U133 Plus 2.0 is a much newer platform and I would expect it to contain all genes that were measured by Affy U95Av2. What does that mean? Should I understand that those 97 gene measurements in the Affy U95Av2 platform were not reliable and that's why they don't exist in Affy U133 Plus 2.0? Here are those 97 genes:

"ACSL4" "ACSM2A" "AP3S1" "AQP7" "ARPC3" "ATF4" "ATP5H" "BAK1" "BAK1P1" "CBX1" "CCL15" "CELP" "CFHR3" "CHEK2" "CLCNKA" "COL8A1" "CS" "CXorf40B" "CYP2D6" "DDI2" "EIF3F" "EIF3IP1" "EIF5AL1" "FCGR2A" "FCGR3A" "GBX1" "GPX1" "HAVCR1" "HBZ" "HIST1H2AH" "HIST1H2AI" "HIST1H2BC" "HIST1H2BJ" "HIST1H4I" "HOXA9" "HSPB1" "IFNA14" "IGF2" "IL9R" "ITGA1" "KAT7" "KRT33A" "KRTAP26-1" "LDHA" "MAGEA12" "MAP2K4P1" "MIA" "MKRN3" "MROH7" "MSX2P1" "MT1A" "MT1B" "NDUFV2" "OPHN1" "OR7E24" "PARP4" "PCDHA12" "PCDHA13" "PCDHGA12" "PCDHGB4" "PINK1-AS" "PMS2P3" "PSMC6" "PSME2" "RAB13" "RCN1" "RNF216P1" "RNF5" "RPL10A" "RPL18" "RPL27" "RPL35" "RPL37" "RPLP1" "RPS15A" "RPS26" "RPS29" "RPS5" "RPS9" "RSC1A1" "S100A7" "SAA1" "SAA4" "SNX29" "SPRR2D" "TOMM40" "UBC" "UBE2E3" "UBE2S" "UGT2B7" "UQCRFS1" "UQCRH" "VDAC2" "VENTXP7" "VOPP1" "XCL2" "ZNF799"


texts:
What dissociates first - the last tRNA, mRNA and release factors or the subunits of ribosomes?

I tried searching this from Lehninger but couldn't get a clean answer.


texts:
When I'm studying stomach cancer, I found that some samples have opposite subtypes in TCGA and 'Comprehensive molecular characterization of gastric adenocarcinoma'. For examples,
'TCGA-CG-4476','TCGA-CG-4444','TCGA-CD-A4MG' were intestinal type in the paper, but they were diffuse type in TCGA clinical data. Could you please help me find out what causes this?


texts:
So throughout my education and research career I have been taught that all enzymes are proteins. This makes sense when you consider enzyme denaturing and folding/shape etc. However, I was recently told by a biology professor that in fact, not all enzymes are proteins -- and he alluded to the RNA world hypothesis and rRNA's.

Could someone explain further how exactly an rRNA (or similar) could be (or not be) considered an enzyme, and whether or not all enzymes are proteins etc?

Thank you!


texts: Perception of distant lights without glasses

texts:
I am fairly short-sighted and wear glasses pretty much all the time. Naively, I would expect that when I take my glasses off, the image I see should look very much the same as as a photograph that's out of focus, or an image to which someone has applied a Gaussian blur filter. In bright conditions this is mostly true, but at night if I look at distant point sources of light, the blurry halos around them appear to have quite a complex structure, and a fairly well-defined edge. Why is this?

To make it clearer what I mean, and at the same time to make a hypothesis about the answer, here is a public domain image of some lights, taken with a camera out of focus:

(image source.) Notice that the image cast by each light is not simply a uniform circle. They are each slightly hexagonal; they are slightly brighter around the edge than in the middle; and there are distinct nonuniformities in the brightness in the interior of each shape.

What I see is actually fairly similar to this but much more extreme. The shape formed by a light is much further from a circle, being very irregular in shape and distinctly elongated in one direction. (This latter is perhaps not surprising given that I have a strong astigmatism.) The bright edge to the shape, and the non-uniformities in its brightness, are much more pronounced than in the camera image.

Now, in the photograph I know that the hexagonal shape is due to the hexagonal aperture in the camera. This can be ruled out in my eyes because my pupils are definitely circular. (Unless some light also passes through parts of the iris?) I would guess that the bright edges are caused by diffraction, and that the nonuniformities are caused by defects in the lens and/or dirt on its surface. I suppose that diffraction and lens aberrations must be the causes of what I see when looking at distant lights without my glasses.

So in the end, my question is mostly just, am I right about this? Are the shapes I see the result of defects in my eye's optics, and which specific anatomical features of the eye are likely to be their main causes?


texts:
What is the difference between Endoproteinase Lys-C and Lysyl endopeptidase?

In the text I'm translating about peptide mapping, "lysine protease" is mentioned (in Russian: лизиновая протеаза). This might be erroneous to translate word for word as "lysine protease". There must be a slight error in the original text. This "lysine protease" is mentioned there due to its use in protein hydrolysis.

I guess that the correct translation might be either endoproteinase Lys-C or lysyl endopeptidase.

I found that endoproteinase Lys-C is used in peptide mapping. Is it synonymous and interchangeable with lysyl endopeptidase, or do they differ in their function? Is endoproteinase Lys-C used more often as a hydrolysis agent in peptide mapping?

Maybe the difference is that endoproteinase Lys-C cleaves "on the C-terminal side of lysine residues", while lysyl endopeptidase cleaves on both sides?


texts: Selective breeding fluorescent sheep - possible?

texts:
I got into a small argument :-)

Friends of mine try to draw fat line between "natural" selective breeding and applying molecular biology (CRISPR/Cas9) to put new traits in existing species. The line of their argument is "GMO is something different, because you can't (in reasonable timeframe, ~1000 years) breed a sheep that will glow in the dark.

Intuitively I think that doing so is possible even without molecular tools to "write" new genes, just using things like horizontal gene transfer and "standard" breeding (I reserve right to use all modern knowledge and tools to plan and monitor progress). I don't have much to substantiate this claim though.

In your enlightened opinion, who is correct?


texts: MCQ - Independent assortment or Incomplete linkage

texts:
Two flies were crossed one wildtype another double mutant sepia(se) and vestigial(vg) yielding 40% wild type 40% se vg, 10% se and 10% vg. The genes show-
a.Complete linkage b.Incomplete linkage c.Independent assortment d. epistasis

My attempt at a solution
Since no. of combination of phenotypes appeared =/= 2 ( there are non-parental traits so) it is not complete linkage.
It is neither epistasis because two genes are controlling two diffrenet phenotypes, not one.
It can be independent assortment or incomplete linkage.
Since the question says double mutant sepia(se) and vestigial(vg) (I am getting the idea that) it is a female and the wildtype individual (with no genotype concerned hint) is a male. The genes are likely on X chromosome.
So..... it is incomplete linkage.
But I'm not sure why not independent assortment.


texts: How is the timing of gene expression controlled in developing embryo?

texts:
I understand how cell differentiation works in general (gradients of homeobox proteins etc), but how is timing controlled? Why do some genes switch on at a very specific moment of development and then switch off.
I imagine that the timing could be enabled by the same homeobox proteins (genes are switched on as soon as the proteins diffuse far enough, and switched off as soon as the homeobox is used up), but perhaps there's some special mechanism of gene expression timing?


texts: What is the point of being selection-free?

texts:
I'm reading "Highly efficient endogenous human gene correction using designed zinc finger nucleases" by Urnov et al. They propose a way to use zinc finger proteins for gene therapy. They repeatedly claim their method is "selection free" and it seems they are claiming that as an advantage to their method.

Why would selection free be an advantage? Wouldn't you have to select for the transformed cells anyway to be relevant in a clinical setting?


texts:
How does (neuro)science characterize "confusion" that occur to "healthy" persons when engaged on a particular mentally-intensive task?

I would exclude the case where we are rationally and with clear arguments deciding one out of many choices (but remain undecided due to lack of sufficient resource/information). My thinking is more towards the case where, for example, we are trying to understand a mathematical problem and its solution, or an abstract reasoning, but in the process get lost: even have no clear idea of what part is 'not understood', or where to start learning (the parts involved) so that we can understand the original problem.

I am aware that I am unable to make my question very clear, I am actually confused how to formulate my thoughts.


texts: Sharks, alligators and Gould's "random walk" theory

texts:
I was thinking about Stephen Jay Gould's view on evolution as pure "random walk" / Drunkard's Walk, increasing or decreasing complexity in basically random fashion, just limited by death if an organism becomes too simple and so increasing complexity without meaning that it somehow confers survival / fitness advantage.

Now, I've read elsewhere that at least some of the shark species (subspecies?) have existed in about unchanged forms for at least 100 million years (correct me if that's wrong) and alligators for 37 million years. 100M years or 37M years is pretty long even for evolution, so wouldn't it create pretty high chance that such long-running species would die out and/or evolve into species even more complex (per Gould's claim of complexity systematically increasing for purely random reasons)? Why would then what seems like about optimum fitness for particular environment persist so long?

Note: obviously I'm not a biologist or even student of biology, evolutionary biology is just my occasional interest. Apologies if I made basic mistakes in premises to this question.


texts: In which organs is water that we drink absorbed into the blood?

texts:
From biology classes I remember that water from food we eat is mostly 'sucked in' (absorbed into blood) in the colon. I guess the same is true for water we drink. But if I eat something, it will reach the  colon after say 4 hours, and if I drink a lot of water, I'd want to go to bathroom earlier than in 4 hours.

So is water absorbed not only in colon?

If it's absorbed in other organs, what % of it would be absorbed in each organ?


texts: Can I imbibe seeds before sterilization?

texts: For an experiment I want to germinate lettuce seeds. For logistical reasons it would be convenient to imbibe the seeds by placing them in the cold for 2 days, afterwards I would sterilize the seeds using dilluted bleach. I mostly see people apply stratification or imbibition after sterilization, does the order matter? Would there be a difference for cold treatment (stratification) or wet treatment (imbibition)?


texts: Chicken Genome what are the LGE 'chromosomes'?

texts: The chicken genome identifies two "LGE" sequences in the chicken genome.  Are these distinct chromosomes or some highly variable sequence from the genome that is put in a separate sequence? I'm thinking they are not really separate chromosomes.... It would be great to know a little bit about their biology.  the papers didn't seem to help me.


texts: Using perceptual adaptation for enhancing realism of VR/other entertainment

texts:
I am quite a fan of the recent oculus rift VR glasses, but it does have several flaws over normal vision, most notably a much less wide field of view, the so-called screen door effect because of too low resolution (example 1, example 2) and often also a certain latency between head movements and corresponding view angle change.

Could one, in theory, create glasses which have these limitations to wear during everyday life to adapt to them, and later have the benefit of a more "realistic" experience?

I know making the glasses is not trivial, I'm just asking about whether the perceptual adaptation part would even work as intended, what timeframe I could expect to adapt in, and how stringent the wearing of them has to be (is waking up without them ok, or should sleep be blindfolded, etc).

Does anyone have experience/advice/knowledge on the subject, maybe even links to prior applications?


texts: Why are market squid attracted to fishing lights but also avoid naturally lit surface waters during daytime/full moons?

texts: Squid fishermen use really bright lights (which can be seen from space!) to attract squid to the surface at night, but a lot of squid also naturally avoid surface waters that are lit during the day (by the sun) and at night (by full moon). As far as squid are concerned, what is the difference between the bright artificial lights and diffuse light that naturally occurs?


texts:
Question from an outsider: have we been able to pinpoint where exactly the feeling of pleasure comes from?

I know that there are several types of pleasure, I'm talking about the 'liking'. If that involves several separate pleasure centers (which is probably the case), I'm interested in any/all of them.

I am wondering if it is the electrical stimulation part, or maybe the release of some chemicals/hormones (but then, where do they go to produce the feeling?), or maybe a chemical reaction somewhere? How much have we been able to narrow it down? Do we know which part of the chain reaction is actually responsible for the feeling of pleasure?

Is it possible to like without a body, just a "head"? Are there experiment on rats (or people) whose body is completely paralyzed?

Any reference to scientific paper, as well as personal opinions or suggestions as to where I could find this type of information would be greatly appreciated.


texts: How much divergence would be needed for classifications as astrobiology?

texts: It is possible that life has invaded mars or the moon by way of probes rovers and other man made tech. How many years or generations of sequential and phenotypical diverge would be  necessary to establish the organism as astrobiology?


texts: Is there any evidence that sexual selection may lead to extinction of species?

texts:
Darwin suggested that sexual selection, especially by female choice, may counter natural selection. Theoretical models, such as a Fisherian runaway process, suggest that evolution of preference and preferred phenotypes may drive each other in ever increasing speed.

Because one male may fertilize many females, one could imagine that natural selection against preferred but energetically costly phenotypes may be weak, and the whole process may not slow down fast enough (i.e., be sufficiently self-limiting). If male mortality is high and their number is low, the random fluctuations may easily cause the extinction of population.

Is there any fossil or experimental evidence that this may really happen?


texts: What is the difference between an antibiotic and an antibacterial?

texts: Concerning medicine, what are the differences between antibiotics and antibacterials?


texts: Why are some organisms able to regenerate?

texts: Why can sponges, cnidarian polyps and planaria regenerate if broken up, but other animals e.g. humans and phylum chordata cannot?


texts: Why is iodine used for metabolic hormones?

texts:
Iodine and related biological iodine-carrying hormones are phylogenetically very old, at least according to Wikipedia. Humans use iodine as a metabolic indicator, as do axolotls and apparently most multicellular life.

So why? Growth hormones, sex hormones, et cetera don't require strange heavy elements not used for anything else. It's not a requirement of transcription factors that they contain iodine.

All I've got for hints is that selenium forms an essential part of deiodinases, as well as forming an essential part of thioredoxin reductase. Thioredoxin is a component used to reduce things around the cell, like thiols and RNA bits and so on and so forth, which I could see being worth the evolutionary cost of running down some selenium.

What's the point of iodine? People have iodine deficiency 'all the time' (it's common enough to be named). Is that a product of agriculture somehow? Are there any advantages to using iodine for metabolic hormones? If there are, what are they?


texts: Does mechanotransduction of cells play a role in the biocompatibility of titanium?

texts:
What exactly is mechanotransduction as the information varies between sources. Some sources indicate that mechanotransduction is the underlying principle where cells pull on the surface they grow on to test their stiffness, so they can stretch and facilitate cell growth and differentiation. Other sources indicate that mechanotransduction is how cells detect mechanical stimuli and turn them into chemical signals.

Is this the main reason titanium is biocompatible to replace bones because it has a low surface resistance and cells on stretch on it?


texts: Myelination of 1st Order Neurons in Spinal Cord Ascending Tracts

texts: When a 1st order sensory neuron enters the Dorsal Column Ascending Pathway (i.e. Spinal Cord), does it get its myelination from Oligodendrocytes (as inside CNS) or it retains Schwann Cell myelination?


texts:
B19 virus (about 20 nm) can; which I think is partially because of its small size; not sure of genomics has something to do with the passing. Rubella's (also called German measles) size is then again minimum 45 nm.
So I started to think if this virus can pass into the brain stem.

Can Rubella pass into the brain stem?

Some studies are made about Rubella associated hemolysis.
I think it is not related with this question at all.
Rubella is diffused along carbon dioxide from capillaries into the brain stem, this is my hypothesis.


texts: How many species can have the same scientific name?

texts: For my science homework, a question came up asking how many species can have the same scientific name. I'm pretty sure that each species has a different scientific name, but just to be sure...


texts: What are the different causes for a snail species to have chiral dimorphism or speciate into a new species of the opposite form?

texts: One way for the snail species to have complete chiral dimorphism where one form is an identical mirror image of the other form is if one form can't reproduce with the other form and it's predator is a species of snake that also has chiral dimorphism. If the snail species has chiral dimorphism and and one form can't reproduce with the other form but the species of snake that eats it does not, that means each individual snake of that species can eat either form and the evolutionary stable strategy is to have a mixture of both forms of snail in unequal proportions; if one form becomes more common, the snake will evolve to change a tiny bit in shape to be better at eating that form and less good at eating the other form so that form will evolve to be less common again. If the species of snail reproduces asexually and has chiral dimorphism and the species of snake that eats it also does, then the evolutionary stable will also be for both forms of each species to be identical mirror images occurring in equal proportions, even if it's very rare for in individual snail of that species to be eaten by a snake. If an asexually reproducing species of snail has chiral dimorphism and the species of snake that eats it doesn't, then both forms of snake will still occurr in equal proportions but the random fluctuations from that equilibrium will be larger because it will be the snake's brain adaption that makes it better at eating the more common form but its brain will already be so well adapted to eating both forms. According to Remi.b's answer at Does the species of snake that eats Amphidromous inversus have chiral dimorphism? and https://www.ncbi.nlm.nih.gov/pubmed/16217668, Amphidroumous inversus has chiral dimorphism occurring in very nearly equal proportions and one form can reproduce with the other form but the species of snake that it's it doesn't have chiral dimorphism. Maybe it can be treated very much like the case where the snail species reproduces asexually and the snake does not have chiral dimorphism but one form isn't quite an identical mirror image of the other form because the identical mirror image of either form would be less able to reproduce with that form and the species of snake that eats it is very close to symmetrical but isn't quite because the two forms of snail aren't identical mirror images. How can predation cause mutants of the rarer form of snail to arise and evolve into a different species entirely? Is it really because no mutants of the predator species of the mirror image form arise getting it into the evolutionary stable strategy where the predator and prey both have chiral dimorphism occurring in equal propertions?


texts: What's the mechanism or structure responsible for new species genetic code generation?

texts:
I always had this question in mind. I think, If humans find answer to it then we can trigger the next evolution of human specie.

What is the mechanism or structure responsible for evolution ? I don't mean the nucleus and the genetic code. because it's the consequence (the result) of evolution.

I mean all that I found right now as studies materials, treat only the consequences of the evolution, similarities between ancestors and descendants..etc

But what process triggers this evolution ?
For example, the birds ancestor (which couldn't fly ), how did his cells generate genetic code to build new proteins needed to build new protein structures and organs and also to keep this evolution's result for next generations ?

Is there any current research on this matter ?

Thank you All for your explanation, but they treat only the case when there is only a certain length ADN chain and this chain will change in time to produce let's say "more effective population ".

but if we say that all the species came from one cell. than this cell had necessarily less ADN then we have now (for ex: it doesn't have yet ADN to code for hemoglobin and other complex proteins)

So my question was Where did the new ADN came From ?

This question came to me, when we were studying bacteriology and one bacteria had all my attention, it's the staphylococcus, they produce a coagulase that trigger the coagulation process to stop the blood stream so the phagocytes and immune cells can't reach there position.

Random mutations ? well random process can have some result in variation and deletion of existing species, but not in building new ADN chains.

don't tell me that the staphylococcus acquired the ability to produce this protein randomly, because if we do some math, the ADN is a base 4 code (there is 4 bases) and to produce an amino acid we will need 3 bases, so for 30 A.A protein we have only one chance in 4 power 90 without adding the random length and the random 3 dimensional structure, I know, even if there is billions of staphylococcus that will mutate all the time there will be nearly 0 chance to produce a protein that can action exactly with the prothrombin.

that's only for one protein.

I Know I have moderate knowledge in biology but I don't believe that errors in a code (mutations) can make it "better" or produce functioning mechanisms that can interact with other organisms, because if we say so, then we are just insulting our intelligence as human being, because we are saying that random process is making organisms that we, with our brain can't reproduce, the proof is we are still using antibiotics and didn't make our immune system more effective.


texts: I recently found some pictures of animals' skeletons. Does anyone know what species they are?


texts: How do baby animals that primarily subsist on cellulose get their initial gut flora?

texts: In the case of mammals like giraffes and koalas, is that bacteria common on the plants they eat so when a baby starts to try to stick something besides its mother's milk in its mouth, it can't digest the cellulose at all the first time, but along with the cellulose, into its mouth went some cellulose-digesting flora that then begins a lifelong colony in the animal's gut? Is that about how it happens?


texts: What kind of eye strain causes an visual aurora effect?

texts:
When I have done too much reading on the PC sometimes I feel a tickling sensation inside my eyeball. At first I didn't even notice the tickle, however my eye would start to see blurred in one area, and a growing halo of yellow blue orange stars grows outwards from one place in my visual field. the shape is not very round, it growns like a mycelium shape, where the border is very bright with stars and lights.

So the effect resembles a mushroom growth ebbing slowly outwards from a point over the space of 30-45 minutes, where my vision in one eye becomes overcome with a blurring effect and a flashing colored araura, and an annoying tickling/electrical effect inside the eyeball. it can be more or less pronounced, and sometimes I can barely read anything up to 1 hour afterwards, and after 2 hours it has returned to normal.

I have 9.5/10 visual acuity, and this started occuring every few months since I was 33.

I can't find what I am experiencing, all the eye disorders and symptoms seem to describe different issues than what i have.

What can it be?


texts:
I found this definition on Wikipedia, but I didn't quit undestand it :

  Topologically associating domains (TADs) are genomic regions ("chromosome neighborhoods") used to summarize the three-dimensional nuclear organization of mammalian genomes.

Can anyone explain it more, and give examples if it's possible ?


texts: When you insert your finger into your ear, you hit a dead end. You can't insert your finger into the auditory canal. What's this dead end called, the medical term for it?


texts: What is it the most common reason for community acquired pneumonia?

texts:
This is a difficult question because there are many types of community-acquired pneumonia (CAP): typical acute, atypical acute and chronic.
Most common microorganisms are also different among different groups: children, adults, elderly, immunocompromised and people at risk of different diseases.

Some options:

Streptococcus pneumoniae
Hemophilus influenzae
Escherichia coli
Klebsiella pneumoniae
Pseudomonas aeruginosa
bronchiectasis
Chlamydia pneumoniae

Not any virus, since they are present in only about 20% of diseases.
Streptococcus pneumonia is probably a good choice.

What is the most common reason for community acquired pneumonia?


texts: Validity of the August Weismann mouse-detailing experiment refuting Lamarckism

texts:
Weismann conducted the experiment — described in Wikipedia — of removing the tails of 68 white mice, repeatedly over 5 generations, and reporting that no mice were born in consequence without a tail or even with a shorter tail. This was intended to refute the Lamarckian idea of of acquired characteristics.

However, surely five generations is too short a time to observe a change in an organ when the fossil record indicates that such changes in animals took millions of years. Was this not known at the time and does it invalidate the experiments?


texts: Is there a limit to acceptable brightness for plants?

texts:
Can overly bright artificial light harm plants? Is it possible to achieve a level of brightness so high that it does more harm than good to plants?

If sunlight can be filtered of infrared light spectrum, so the plants don't burn from high temperature, but if it's possible, then that too.


texts: How can fresh cavities form at the margins of sliver amalgam fillings on teeth?

texts: Silver amalgam fillings predominantly contain silver a known bactericidal agent and mercury which a known toxin and has bactericidal property. So how is it that the plaque bacteria survive near the filling margins and produce fresh caries?


texts: What species is this bird (found in Cousset, Switzerland)?

texts: A friend of mine saw that bird in Cousset, Switzerland but it doesn't look like anything we know or we've already seen before around here. Does anyone have an idea of what species it could be? Thank you in advance (and sorry for the bad quality of the picture)!


texts: What is this abbreviation CT in female reproductive system

texts:
I have this sentence in my notes

  Ovary is surrounded by tunica albuginea and the cortex keeps the primordial follicles. The medulla containing CT and blood vessels develop from mesonephros.

I have these words in my mind about CT

tunica
cyto- (maybe cytotrophoblast)
corona (no other than corona radiata so not)

What can CT be here?


texts: Internet says that the carotene is an important pigment for photosynthesis and UV-protection. That explains its accumulation in leaves. I suppose colored fruits are more appealing to animals, so that explains the fruits. But why roots? Why is carrot full of carotene? The only reason I can think of is human cultivation. Is there any specific reason carrots synthesize so much carotene? Are there other similar examples of so vividly colored roots?


texts: How does the eukaryotic cell synthesize all of the proteins of a protein complex (like ETC complex I) at stoichiometric ratios/numbers?

texts:
(eg synthesize all proteasome proteins at the appropriate ratios to which they are used)
How often are proteins of the same complex (eg all the proteins of the 20S/19S parts of the proteasome or complex I of ETC) controlled by the same enhancers/promoters? Is it often the case that you just have non-stoichiometric synthesis and then the cell degrades the excess protein if it can't put them both together?


texts: Why is fructose not glucose the main energy source of sperm?

texts:
The seminal fluid contains fructose as the main energy source for the sperm and not glucose.

  Why is fructose and not glucose the primary energy source for these
  sperm, since glucose is the preferred energy source for most other
  tissues?


texts:
I'm studying the digestion of fats and I understand that our dietary fats mostly consist of triglycerides. We absorb the fats and eventually they end up in a muscle/adipose cell for storage (as triglycerides) or for oxidation for energy.

However I don't understand exactly where cholesterol plays in? I read about lipids being synthesized by the liver being exported by VLDL and then taken up by cells. We're moving closer to cholesterol here but I still don't see the connection.


texts:
I am reading a journal paper on the effect of a neural cell adhesion molecule on neuronal development and in the abstract of this paper I have come across the following:

The autophosphorylation and activity of Pak1 were enhanced when
isolated growth cones were incubated with NCAM function triggering
antibodies, which mimic the interaction between NCAM and its
extracellular ligands.

In this paper, the NCAM protein becomes activated when it is exposed to NCAM function triggering antibodies. I understand that antibodies are molecules produced by the immune system and bind to antigens. However, I am not sure how incubating growth cones with NCAM triggering antibodies would actually trigger/activate the NCAM protein itself.
Isn't the purpose of an antibody to bind to an antigen  so that it can be removed from the body? I am not sure how exposing an antigen its respective antibody would trigger its function. I have read several other papers about neural cell adhesion molecules where antibodies were used to activate their function. I have searched function-triggering antibodies on Google but I have found no useful results regarding this. Any insights are appreciated.


texts: What is a unitary post synaptic potential?

texts:
I am reading the paper Cooperative subnetworks of molecularly similar interneurons in mouse neocortex and have encountered the term:
"Unitary (excitatory or inhibitory) post synaptic potential".
I know what is an excitatory (or inhibitory) post synaptic potential.
But what does the unitary refers to?

Thanks!


texts: Are alleles passed down and shuffled randomly to the offspring during meiosis or fertilization?

texts: If it does occur during meiosis, are the alleles switched over from one sister chromatid to the other during the crossing over process in Prophase I?


texts: What are the main principles of the Bacteriological Code?

texts:
Although the Bacteriological Code is an important guideline for taxonomists and microbiologists, describing the criteria for delineating species and higher taxa of the prokaryotes, I, and plenty of other microbiologists with me, would not be able to describe the main rules by heart. I am also not able to find a clear summary anywhere on the web, and reading and understanding the Code itself is currently taking quite some time.

Furthermore, does the Code say anything about taxa mainly or solely composed of uncultured strains based on 16S sequences, apart from the addition of Candidatus to currently uncultured single species? I am specifically referring to higher taxa, large groups of sequences.


texts: Why there is more chances of injury to carotid vessels in zone 1 although if palpated carotid pulse  is best appreciated in zone 3(then it is supposed to be superficial).?


texts: Do strictly anaerobic organisms use metabolic reactions requiring oxygen?

texts: When looking through genome annotations of strictly anaerobic organisms I see reactions featuring oxygen. I suspect these are likely an artifact of the annotation process. But I am wondering if it is possible for such organisms to have oxygen associated metabolism. Strict anaerobes are known to die in the presence of oxygen due to the lack oxidative stress pathways. So I cannot think of any reason for oxygen to be part of their metabolism.


texts:
I found the question about tear gas very interesting. Shigeta says there that crying helps the cells of the eye to wash themselves clear of the toxic components in the tear gas.

Does non-emotional tearing always work this way? Is tearing not caused by cells in the tear duct working as receptors? If not, why we have tear duct (the first in-eye part of it)?
What is the cause of tear-production associated with crying during strong emotions? Is it due to hormones or nerve activation?


texts: Determining and Differentiating specific ATPases

texts:
In respects to this certain ATPase transporter. What do i look for in respects to determining what specific kind it is out of:

F-ATPases
V-ATPases
A-ATPases
P-ATPases
E-ATPases

Im assuming that analyzation of the gradients dealt with will guide me to the answer. With that logic, i can assume that this is an F-ATPase since i know this membrane protein can synthesize ATP using a H+ gradient, and work in the reverse to create a H+ gradient using the energy gained from the hydrolysis of ATP.( I see 2H+ cations being expelled) Is this a correct method in differentiating ATPases ?


texts: Which kind of drugs get absorbed through epidermis?

texts: Some drugs such as nicotine can be administered through skin. I thought the layers of skin are designed to prevent in-flow of any chemical/germs. Not all drugs get absorbed in this fashion. So do drugs like nicotine have any specialities(such as a special chemical group) that fool the sentries of skin? A link to an article/site would be very helpful, or even a book recommendation.


texts: Do residue sequence numbers in PDB files correspond to the positions in the backbone?

texts: In other words if two residues have sequence numbers, say, 20 and 21 then are they next to each other in the backbone? If no (or not necessarily) then is there any way to find consecutive residues from a PDB file?


texts:
Dicrocoelium dendriticum is a parasite that uses ants as a second intermediate host (which means that ants aren't its primary host/target, but are rather a temporary host to help reach their main/definitive host: sheep).

When ants are infected, this parasite causes them to climb onto the top of grass blades, which increases the chance that sheep will devour the ant along with the grass, helping the parasite reach the sheep.

My question is: how do parasites such as (but not limited to) that described above "reprogram" the minds of the hosts? I know that brains are incredibly complex, so I'm fascinated and curious about how a parasite can change the behavior of its hosts - which I'm assuming is only possible by modifying its brain? If so, how do they do this?


texts: What is the effect of persistent hypothermia on cardiac performance?

texts:
I define persistent hypothermia in this thread about the mechanisms of persistent hypothermia.
The Graph of Katzung et al. in Pharmacology about Heart Failure:

I am thinking which parts here are critical on temperature.
Temperature has a direct effect of reaction rates of chemical reactions here, for instance NE, AII and probably chemical reactions in endothelin such as ET.

Therefore, I am thinking that the relationship between temperature and cardiac performance cannot be linear at all.
Some have said me that low temperature can decrease metabolism and oxygen consumption.
However, I started to think differently when time goes enough far that is when heart cannot anymore supply enough blood with oxygen. Thus, hypoxia can occur and asymptomatic exodus may occur.

Physiological case

Based on physiology, I can propose that the cardiac output curve shifts to the left (CO1 $\to$ CO2), due to less oxygen being supplied to the heart, similarly EDV1 (end-diastolic volume) shifts $\to$ EDV2 and SV1 (stroke volume) $\to$ SV2.
However, the venous return (VR) curve can shift much more, since I propose that the effect of temperature on smooth musculature is relatively bigger than on heart because of proportional size of tissue.
So the VR1 shifts to VR2, so EDV2 $\to$ EDV3 and SV2 $\to$ SV3.
Consequently, SV3 > SV1, while EDV3 < EDV1.
See my draft figure about this:

where EDV (End Diastolic Volume) in the x-axis and SV (Stroke Volume) in the y-axis.

In a healthy person, who have no hypertrophy of ventricles and elastic myocardium, the heart can tolerate this. So such a condition of cardiac failure as in the figure 13-3 is possible.

However, if flexibility of the myocardium, for instance, is not possible, such a pathway may not be possible.
The autonomic nervous system may enter the picture and increase vagus nerve stimulation (PS more).
However, not sure about the exact pathway.

What is the effect of temperature on cardiac performance?
How can temperature decrease cardiac performance?


texts: What is the difference between vegetable and animal fats?

texts:
I often hear from many people saying to waiters - "Please, don't put oil to salad". They probably believe the fat from vegetables has the same impact on the weight as an "animal" fat (meat, eggs, butter).

My questions are -

Are these two types of fat have equal influence considering their converting to fat tissue in humans?
What are the pathways for conversion of vegetable oil fats to adipose tissue storage, in humans?
If one eats $X$ grams of either saturated or unsaturated fats, will they (in equal conditions) gain equal weight ($Y$ grams) in both the cases ?


texts: What is the 'fallacy' in simple segregation rules in reference to polyploidy?

texts:
I was reading a paper Why polyploidy is rarer in animals than in plants’: myths and mechanisms, Mable 2004 where I found this sentence.

  Stebbins (1950) suggested that autopolyploids were probably more frequent than often considered because of the ‘fallacy’ that simple segregation rules (i.e. auto- polyploids showing multivalent associations and allopolyploids showing bivalent associations) can be used to distinguish modes of origin.

What does it mean? I know that autopolyploidy is where the chromosome sets are from the same species and it is the other way for allopolyploidy. What do segregation rules mean here and what is the fallacy?


texts: What amount of protein comprises the feces of a domestic cat?

texts:
I've heard it said that the fecal excrement of cats, Felis catus, contains adequate amounts of protein so as to attract the interest of other animals e.g. dogs (Canis familiaris).

However, I am unable to locate any studies which reported the composition of a cat's feces as compared to those of any other animal with regards to a controlled quantity of proteins in the diet.  I do see a lot of people on the internet making claims one way or the other, but never a citation to be seen.

Would anyone be interested in citing some references here so as to provide a more reputable resolution to this oft–repeated “fact”?
Unlikely as that would be, I'll post an answer here next time I check the university library.


texts:
Developmentally male rats don't have nipples because (reddit)

  Testosterone release in the fetal male rat happens before the stage of mammogenesis where the teat is formed whereas other species halt that same process after the teat is formed.

According to the same page, male rats and horses (and mice) are unique among non-monotreme mammals in not having nipples.

Male humans have nipples because there's no evolutionary pressure for them not to. (Why do men have nipples?) Then, why was there selection for males to lack nipples in the case of mice, rats, and horses?

(Apparently, male horses lack nipples because "female horses have their nipples between their hind legs, and in males, that real estate is used for other purposes". (Straight Dope))

Evolutionarily, why do male rats and horses lack nipples?


texts: Is the function of a co-enzyme to make a reaction run quicker? If catalysts speed up reactions, and enzymes are catalysts, and co-enzymes make enzymes work better, does that mean the co-enzymes just make reactions quicker?


texts: Why is the  microbial ecosystem of the gut so susceptible to disruption by pathogens?

texts:
From all accounts, it seems as if the Escherichia, Enterobacter, etc. that live and thrive in the human gut are pretty well entrenched.  I know that these microbial populations are often analyzed as an ecosystem.

What surprises me is that it seems like minor food poisoning can throw the whole ecosystem off.  I know superficially that Clostridium are contenders in the fight because they remain viable after traveling through the acid of the stomach, but why are these populations so sensitive to other invading bacteria?


texts:
I'm from South India and I'm having quite a fuss identifying this plant. It has totally transparent stems, and when I break them, water squeezes out. My local friend tells me that this was used in the olden days to clean slates. It has a bit fat stem. And another thing about this plant is that when you soak it in Ink, you can see the ink travelling up it. That's why it is so transparent.

I heard that it is locally called Mashithandu and I searched all  over the net for it, but can't find a name except that. I'm really sorry I can't add a photo. I'll see what I can do.


texts: Is lowered blood pressure a primary lethal symptom of an opiate overdose?

texts:
When someone has a opiate overdose, they can have no or almost no pulse and can  have shallow breathing or stop breathing. When you stop breathing (for example) by drowning, you can survive for a long time without breathing, so it seems that stopping breathing because of the overdose won't kill very easily.

Is the lack of (detectable) pulse due to the blood pressure going really low instead of the anecdotal explanation that the heart has stopped? Can the low blood pressure be more immediately dangerous than the reduced breathing because it makes the heart's pumping ineffective and cuts off oxygen from the brain?


texts: I have read in wikipedia that the first dengue virus infection is cleared by the body very easily. The second infection, however, is dangerous. How does body fight second infection, or does it has any tool to fight it given earlier antibody will be ineffective?


texts: Why do we have no enzyme to digest cellulose?

texts: As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have an enzyme to digest cellulose?


texts: Why do many fruit trees have five-petaled flowers?

texts:
Peach, pear, apple, cherry, and many other fruit trees seem to have flowers comprised of five petals. Assuming there is no evolutionary advantage to confusing students of trees, is there a plausible reason (evolutionary or otherwise) the morphology is so regimented? Are the trees related? Do they like the same pollinators?

Thanks for any insight.


texts: Where do the H+ ions come from in light reactions?

texts: In the light-dependent reactions of photosynthesis, H+ ions pass to the thylakoid space. Where do these protons come from?


texts: What does it mean for a distribution to be "consistent with a two rate-limiting stochastic steps"?

texts:
I'm reading a study (full text here) that examine the dynamic of nuclear translocation of a transcription factor in budding yeast, in response of calcium stress. They found that it occurs in bursts, which distribution of durations is plotted on this normalized histogram:

In the text they say:

  Normalized histograms, $h(t)$, of total burst duration at two calcium concentrations are both well-fit by $h(t)=te^{-t/\tau}$, with $\tau$ = 70 sec (black line).

And also

  This distribution was consistent with two rate-limiting stochastic steps, each with a timescale of ~70 sec.

Can someone explain me the second sentence cited?


texts: Are these fruit flies really coming back to life after being frozen?

texts: I've found this video on Reddit where they pretend these are frozen fruit flies coming back to life... I didn't find any publication related to this specific experiment. Is this just a fake video?


texts: How do molecular recognition features work?

texts: The occurrence of relatively short (10–70 residues), loosely structured protein regions bind within longer, largely disordered sequences that were characterized as bound to larger proteins. These regions are MoRFs. But how do these high specificity regions combined with low affinity proteins?


texts: What mammals can rotate and move their ears the most?

texts: I found out that rabbits can rotate their ears 270 degrees, and also move them up, down and independently. Are there any other mammals that can control their ears' position that well, or even better?


texts: How does natural selection explain how organisms that are poisonous evolved?

texts:
Natural selection makes perfect sense when describing the evolution of say camouflage. For example 2 bugs of the same species live on a tree. One is mutated to look slightly more like a tree, so the bird misses it and eats the one that sticks out more.

This logic seems to fail for poisonous animals though. For example, two bugs are equally visible but one has developed a mutation to be poisonous. Since they are both easy to spot they both get eaten. Now the poisonous mutation has died out. How does natural selection explain the poison mutation overcoming the initial hurdle?


texts: How do we know we are made of stardust? As our cells divide, are our atoms repurposed from existing materials or spontaneously generated? Do we consume materials after we are born that contain elements that were in stars? This I would understand. Or, as our cells are initially dividing after conception, but before birth, are we already repurposing existing materials to grow?


texts: Is each blade of grass an individual plant or not?

texts:
Sometimes when I do gardening, I notice multiple blades of grass appear fused together at the root, yet still appear to be segmented. When I look at images, I get some that suggest each blade is an individual plant like this one, and I find ones that suggest they're fused together like this other one, and I wouldn't know if they're actually fused or if they just have a tendency to have seeds or roots distributed in a clumped manner as some survival strategy.

Should it be assumed that each individual blade of grass is a separate plant, or otherwise how many blades are part of the same plant?


texts: Do the two catalytic cores of DNA polymerase III operate in the same direction?

texts:
This diagram is from Molecular Cell Biology by Lodish, 2000 which states:

The other core-polymerase molecule, which elongates the lagging strand, moves with its β-subunit clamp in the direction opposite to that of the fork movement.

Again the images provided in Principle of genetics by Simmons, 2015 and Cell Biology by Karp, indicate that the catalytic cores are directed in the same direction. The following diagram is from former book.

Which one is correct and why(please provide citations)?


texts: How do you differentiate between SR protein and SR-like protein?

texts: What are the criteria that the researchers use to choose whether a protein is an SR protein or and SR-like protein?


texts: Mammalian advantage at filling large-animal niches after the KT extinction?

texts: Larger animals are more prone to extinction due in part to smaller numbers. The asteroid that impacted 65 million years ago killed off the larger mammals and dinosaurs but spared some of the smaller ones. The smaller niches were refilled by both mammals and Theropods (as birds), but there is a paucity of large bird species. Is there a reason mammals were better at refilling these large-animal niches?


texts: What level of cellular radiation is harmful for humans?

texts: What level of radiation at the frequencies used by the cellular network(1-2 Ghz) is harmful for human health?


texts: How is Coenzyme A Transported to the Matrix?

texts: So, I've been researching cellular respiration on my own, and trying to keep track of most of the major processes. However, I do have one question left: I can't seem to find any sort of information about how Coenzyme A (I think it's made in the cytosol) is transferred to the matrix (the inside of the mitochondria, inside the inner membrane). Is it transported with a shuttle like for NAD+/NADH, a translocase like for ATP/ADP, or something else? Thank you for your time.


texts: Loooking for dataset of proteotypic and non-proteotypic peptide

texts:
I'm experimenting with peptide prediction using machine learning. I need some data for testing. I already have one dataset, but I need another one or two for verification.

I'm looking for data for a proteotypic peptide and a non-proteotypic peptide.


texts:
My crude understanding of how people normally go about building muscle is something like this following 2 step process:

1) a person can lift weights (for example), which tears muscle and stimulates the nervous system.
2) They can then eat protein and get sleep, which build the muscle back up stronger than it was before, as the nervous system tells the body that more muscle is needed to handle the type of stimulation its been getting.

Now to my question: exotic training techniques like EMS exist which do the same in principle as lifting weights.  What about something as simple as the muscles taking a beating (as in kickboxing)?  If a muscle is battered in a systematic way, will it be built up stronger as per the muscle building process?  If so, what type of muscle would this be (Fast twitch/slow)?  Would it transfer well to overall strength?


texts: How long does each of the stages in meiosis take?

texts: For each stages of meiosis (i.e. Interphase, Prophase I, ...), I wanted to know the time between each stages either in percentages or minutes. However, while I could find the cell cycle for mitosis like the image (original link), I couldn't find such thing for meiosis. Does anybody know anything about this?


texts: Is this a large bee? (species identification)

texts:
While hiking in some low hills near Taipei in the late afternoon in July an hour after it rained, I saw this large flying insect visiting flowers the way bees do.

I'm curious, is it a bee (if so, what kind), does it come from a hive or live on its own, and does it sting?

I'm estimating its body to be about 5 cm long. While not captured in photos, I'm pretty sure I remember it sticking its head into flowerers. It was moving flying from place to place fairly quickly and difficult to get any photos at all, this is the best I could do.

edit: Since further clarification of the size was asked for in comments, I'll add here also that the length of "about 5cm" that I mentioned wold be for nose to tail when stretched straight, (rather than in it's current somewhat curled position) and it could certainly be 4.5 cm. But I'm fairly sure it's closer to 5 cm (2 inches) than to 4 cm. I've added a few more images of the flower sans insect. I've cropped my friend on the left out of the images.


texts: What evidence do we have to derive a rate of evolution?

texts:
When analyzing how the human species evolved and will continue to evolve over time, what evidence and tools (theory/models) do we have available to derive the rate at which this happens? Is it even possible to set reasonable bounds on such a rate?

Also, how large is the available dataset? And how does the dataset match with theory? I would especially like to get an idea of how well statistical (Bayesian/likelihood) analysis matches with empirical data and more conceptual models.