texts:
Introduction

Selective sweep is the most famous genetic signature of selection. We know of a number of classical examples of selective sweeps, some of them in humans. See the classical example of the sweep on a sequence relgulating the lactase gene in the post Are humans the only species who drink milk as adults?.

Question

I do not have a good intuition about how common such sweeps are. Are there constantly 5 to 10 sweeps happening in a species genome or is there a sweep every 1000 generations only?

How frequent are selective sweeps?

Clarification

Of course, the answer will vary (and will probably vary greatly) among species. I would welcome empirical estimates and/or theoretical expectations coming from any species (I would prefer an estimate coming from a eukaryote species though).


texts: What could an increase in systolic blood pressure and decrease in diastolic mean?

texts:
Sorry if this is a really simple question but my academic background is in completely different sciences. I recently made a computer game for an experiment that was related to anxiety and relaxation. One of the ways that I measured for success was to record participants blood pressure before and after they played the game.

There was a slight increase in systolic BP after playing the game, but not by a statistically significant amount. However the data shows a decrease in diastolic BP that is statistically significant. I've been trying to figure out why this might have happened but can't seem to find any answers. My brief overview of search engines and journals only seem to relate these changes to certain types of exercise. Which doesn't help as the participants of the experiment were asked to remain seated for 20 minutes by the time the second BP recording was made. Just wondering if anyone has any information in relation to relaxation techniques that might result in this pattern?

If it helps heart rate has mostly uniform throughout the experiment.


texts: Before I move my arm the brain sends signals - what causes the brain to send signals?

texts:
Please tell me what causes the brain to send signals, how does the brain send signals?
can you tell me what happens between the point when you make an intention to pick up a glass of water, and before the brains sends signals to the body which excites the muscles.

So what happens at the moment when you make the intention to pick up a glass of water but before the brains sends signals after you reach to pick up a glass of water.


texts: What part of the cactus photosynthesizes?

texts: In general, plants photosynthesize through their leaves and, to a much lesser extent, through their stems. Cacti, however, have no visible leaves, but instead spines. In what part of the cactus does the photosynthesis take place?


texts: If a bacterium had a protein on its surface that humans also have, would it cause an autoimmune disease?

texts:
Suppose that a bacterium happened to have a protein on its surface. This protein can also be found in the human body. If this bacterium were to then infect a human with an otherwise normal immune system, would his/her immune system attack the person's body, in addition to the bacterium?

The reason I'm asking this is because I have read a book about how, supposedly, the Soviet Union created a bacterium that did just that: they modified Yersinia Pestis to produce myelin which, supposedly, caused multiple sclerosis. The book's author claims that this really happened, but I am skeptical of that claim.


texts: Why doesn't a substance like loperamide promote analgesia?

texts:
Loperamide is frequently used to slow gastrointestinal motility.  It is available over the counter (in the US, I don't know about elsewhere) without any regulations whatsoever, yet it's derived from an opiate.  Knowing that the opiates slow the intestinal motility, it makes sense that it shares the same side effect.

What doesn't make sense to me is why it doesn't share the same primary effect of analgesia?  Clearly it binds to opiate receptors in the gut, but are they the same subtype as those in the CNS?  Or is it that the structure of the drug is such that hardly any crosses the blood brain barrier?


texts: Is there any measure by which the Germans today could be called a genetically superior race?

texts:
The Nazi eugenics programs are well known. Despite their controversy, I cannot find any indication on their effectiveness. Were there ever and studies done on the (arguably subjective definition of) superiority of German genetics due to (or possibly in spite of) these programs?

Do we even have a way to objectively measure genetic superiority or fitness? In the case of a lack of such a measurement, the idea could be qualified for purposes of this question as:

Lower instances of genetic disease.
Lower instances of mental retardation, criminal tendencies, and mental illness.
Higher general academic achievement.
Healthier, longer lived population.

Note of course that I am not promoting or condoning eugenics in any way. I am only interested in knowing if the results were effective (i.e. achieved their goals), without comparing the programs' possible benefit against its obvious drawbacks. All contemporary discussion of the programs concentrate only on the drawbacks, unfortunately.

EDIT: Before anyone accuses me of bigotry or crimes against humanity, I will mention that my grandfather lost all seven of his siblings, his parents, and all the rest of his entire family to this same regime. My grandmother lost five of eight siblings, both parents, and all the rest of her entire family to this same regime. What these people did to Jews, Gypsies, and the feeble was terrible and I do not excuse it. This question is intended only to concentrate on the scientific issue of forced, deliberate genetic improvement, a form of "breeding" if you will.


texts: Does melanin protect against nuclear radiation?

texts:
It is known that melanin protects against UV radiation.

But say a nuclear bomb dropped somewhere would more people of dark complexion survive the radiation burns because the melanin would protect them?

Or as another example, suppose there was a meltdown and someone had to swim into the reactor to pull out the core, would it be best to send the light skinned or dark skinned person to ensure maximum chance of survival? All other things being equal.


texts: Biological siblings possible with <9 months age difference?

texts:
I'm currently in the middle of writing a story, and one of the story elements threw up a question for me. In this story, there are two siblings, who are only one or two months apart in age. As they grow older, they start to question how this age difference is even possible. How could their mother have had another child after just a month of giving birth to the first child? They suspect that they're not related and don't actually have the same mother, and it turns out that it's true.

I want to know if that suspicion is justified. I began to think of ways two siblings can be less than the usual nine months apart in age and yet still be related to each other. One idea I had was of twins, one of whom is born earlier, while the other had to stay inside the womb for another month for whatever medical reason.

Basically, my question is: can you have siblings (with the same mother and father), who are less than nine months apart in age? And if yes, how?


texts: What is the protein sequence taken as input in the Path-A prediction system

texts:
Considering the Path-A based metabolic pathway prediction (http://nar.oxfordjournals.org/content/34/suppl_2/W714.short). It uses machine learning for pathway prediction. Suppose that the input was a protein sequence of a query organism. I do not understand what these protein sequences are? Are these the enzymes for the reactions?

  The basic algorithm has two inputs: a set of protein sequences from the query organism and a set of model pathways, one for each target pathway.


texts: Where can I get a file/list of the common and scientific names of species?

texts: I am searching for an un-encoded data file with common and scientific names for example of a few hundred species or tens of thousands, where I can search the common and scientific labels of organisms.


texts:
During sleep, our body activity decreases. I am wondering on the extent of the lowering of this activity regarding our five senses. Clearly, the sense of touch is still very efficient since shaking a body is the most common way to awake someone, and hearing is also quite unaffacted (most, if not all, alarm clock, rely on this sense). Most deaths due to fire are due to intoxication rather than the burnt of the fire, so it suggests that smell and taste are pretty dimmed during sleep.

My main question: To which extent each sense is dimmed during sleep?

For example,

Can we smell during sleep? I don't remember having been awoken by the smell of something during my life...
Similarly, can we taste? If someone gives me delicious food during my sleep, would I be able to feel its taste and remember this experience?
Can we see? REM are well known but it is a mechanical feature of the sleep. Some people sleep with the eyes opened: what do they see?

Note: This related question tries to explain how senses are dimmed during sleep but not how much they are.

Note 2: I am aware this is person-dependant: any sound would awake my mother (a skill during my nightly escapades) whereas I would not notice a party around me when I am in deep sleep. But there should be some kind of average... It also depends on the phase of sleep; I am mostly interested in deep sleep and REM sleep, but an answer detailing every phase would be awesome.

Note 3: This question is certainly naive in its current form. Please help me to improve it.


texts: Is there any ethnicity difference in average pupil size?

texts:
I have seen some articles claim African Americans have smaller average pupils than whites while Asians have larger pupils. Is it true?
link:
Y. Li, D. Huang; Pupil Size and Iris Thickness Difference Between Asians and Caucasians Measured by Optical Coherence Tomography. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5785.


texts: What are common causes of unexpected ligation products?

texts:
I digested two plasmids, one with EcoRI and AgeI and the other with EcoRI and XmaI. Digests looked as expected, so I purified the respective fragments and set up the T4 DNA ligation (AgeI and XmaI sites are compatible).

After E.coli transformation, culture and miniprep from 12 of the resulting cultures, I digested the isolate from the minipreps with BclI to confirm I had the correct product (because there was one BclI site in the insert and another one in 1.4kb away in the backbone). The results of this digest clearly show that there are two different ligation products: four lanes share one banding pattern and the other eight share a pattern which is different from it.

I checked both plasmids for other restriction sites of the enzymes used which I overlooked before, but found none. Because EcoRI and XmaI/AgeI sites are radically different (AATT vs. CCGG), I would exclude the possibility of the insert being ligated in reverse orientation.

Are there any common causes of unexpected ligation variants besides unnoticed restriction sites and reverse ligation?


texts: Creative ways to deactivate alpha-amylase taken from fungi

texts:
I can deactivate $\alpha$-amylase in ways such as extreme temperature controls, pH controls of the solution it stays in, or adding salt to the solution.

However, are there any other unique or elaborate ways to deactivate the enzyme? (maybe the lock-and-key hypothesis also works for enzymes AND enzymes?)


texts:
Is there such a thing as cysteine deficiency in humans or other mammals?

What effects would such a deficiency have?

As I understand it, most cysteine for humans comes from dietary sources, though it can be biosynthesized in humans.


texts: Would salt cause a pistachio nut not to be able to germinate?

texts: If I buy a bag of pistachio nuts that have been hand picked off the tree when ripe, then salted in a (light) saltwater solution, then vacuum-sealed, and stored in a refrigerator, then will they germinate if I take them out and soak them in a moistened towel laying out in the sun?


texts: Why are interspecies hybrids so often larger than either parent species

texts:
Recently doing a little reading on interspecies hybrids I noticed that it seems interspecies hybrids are most often much larger than either parent.  Notably, Ligers, Dzo and Savannah Cats, but it seems like all or at least most.

Is there a reason for this genetic expression in hybrids?

If I am incorrectly inferring this to be the case let me know that instead.


texts: How do trees manage to grow equally in all directions?

texts:
I was walking down a road with these beautifully huge trees when this question occurred to me.

Large trees with many thick branches have to grow equally in all directions, or they would tip over. Is there some sort of mechanism to ensure this uniform growth? Or is it just a happy coincidence arising from uniform availability of sunlight on all sides? If one branch of a tree becomes too heavy due to many sub-branches, does this somehow trigger growth on the opposite side of the tree?

I have seen that potted plants in houses tend to grow towards sunlight. My mum often turns pots around by 180 degrees to ensure that plants don't bend in any one direction. I assume that this is because sunlight increases the rate of photosynthesis, leading to rapid growth of the meristem.
For trees growing in open spaces, this wouldn't be a problem. But there are many large trees that grow in the shadow of buildings without bending away from the buildings, even though this is the only direction from which they would receive any sunlight. Is there any explanation for this?


texts:
Throughout various species, there seems to be a clear distinction between the front and the back. The musculature of the front, when engaged, closes or curls up the body, protecting it, while the musculature of the front straightens and stiffens. This feels intuitively to me like a pretty fundamental pattern.

Is this a "real" pattern at an embryological level, or just a common pattern of adaptation?

Is the innervation of the front and back musculature neurologically distinct in any way?

Which biological systems show a front to back separation?

How early in evolution does a front to back distinction occur?


texts: Lacking other resources, could a healthy adult slit his wrist to feed a starving child with his blood? Would it be nutritional and would a starving dehydrated child eat it?


texts:
When one studies cell division, usually the process is explained through what happens with the DNA of the cell, particularly, that in eukaryotes the nucleus dissolves. But what happens to the rest of the organelles? I read here what happens to the ER and Golgi complex, in particular I'm wondering what happens to the mitochondria, in which part does it reproduces? do they make a parallel process? or do they get dissolved?

$%---------
%I started wondering about this because I was reading Lynn Margulis' article _Bacterial Bedfellows_, and it baffles me that in such little time an organism can just coexist with an attacker and turn it in a _good relationship_, how ever it's not clear to me how cell reproduction might work in those cases.$


texts: Examples of intracellular parasites of medical or economic importance?

texts:
What are examples of intracellular parasites of medical or economic importance? I have read that Xanthomonas oryzae is an intracellular parasite in rice that produces proteins able to cause changes in the gene regulation of the rice cells in order to feed off the sugars produced by the rice cells.

I would like to know of other examples of intracellular parasites of medical or economic importance that would be potentially (even if not tested) able to interact with the host's genome in a similar manner.


texts: Is it possible for a human to live forever if he/she didn't catch any diseases?

texts: Aging is not a disease, but it's the gradual weakening of the body, as the body gets weaker it gets more prone to diseases. So one doesn't die from aging but from diseases. So if one didn't catch any diseases, would it possible for him/her to live forever? Or just longer than the maximum life span?


texts: Why do we have such a wide range of responses to pathogens and carcinogens?

texts:
I was reading an article recently debunking the idea of 'boosting' your immune system. It occurred to me that - presuming it's right - our immune systems are all pretty much the same (with the exception of the immunocompromised). Given this, I wondered why there is such a disparity in how people respond to pathogens or carcinogens.

Most people would be quite happy, for example, to say that poor food hygiene causes food poisoning or that smoking causes cancer, but in actual fact, most of the time they don't. People who have poor food hygiene standards have them every day, but they're not sick every day, they're sick once in a while. Only 25% of heavy smokers actually get lung cancer, even with something like Asbestos, only 1 in 10 former Asbestos workers actually get Mesothelioma.

What is it that protects most people from these diseases despite definitely encountering the pathogen/carcinogen concerned?

I realise the most obvious answer is the immune system, but that just shifts the question to why this doesn't protect everyone all the time. Presumably the immune system doesn't just have a day off every now and again


texts: GWAS: marker map based on old genome assembly - can I use the new assembly to look for SNP positions?

texts:
I have an old set of pig SNP data and the positions were mapped using v10.2 of the assembly.

I submitted a GWAS paper for review, and the reviewer wants to know if any of the significant SNPs that were located in previously unknown genes are now in known genes, with the release of the latest assembly last year.

I was under the impression that I had to use the assembly the marker map was based on to see where SNPs are located. Is this correct or can I use the new assembly?

Many thanks in advance!


texts: What is the most genetically simple organism except viruses?

texts:
What is the most genetically simple organism (except viruses) on this planet?

By simple I mean the least number of genes.


texts: Does muscle growth trigger angiogenesis?

texts:
So heavier people generally have more blood than lighter people (this is why heavier people generally need to take higher doses of medication for the same effect of medication). They also have more blood to draw from. But this fails to differentiate between muscle mass and fat mass.

So here's my question: Is the net angiogenesis per gram of muscle more or less than the net angiogenesis per gram of fat?


texts: Why does exposure to a smell for some time reduce the electrical response of receptor neurons in the olfactory system?

texts: In what way does exposure to a certain smell for some time causes them to loose sensitivity and have a lesser electrical response


texts: If D1 receptors stimulate adenylate cyclase (through GPCRs) and D2 receptors inhibit it, then why do mutations in both have similar effects?

texts:
D1 and D2 both refer to specific types of dopamine receptors.

I'm sure it has something to do with the fact that the D1 receptors are in regions different from D2 receptors.

I know that adenylate cyclase usually triggers a signal transduction cascade that leads to increased cAMP+calmodulin, resulting in increased gene expression of proteins that help promote long-term potentiation of postsynaptic neurons (presumably lowering the absolute value of the voltage threshold that's needed to trigger another action potential, which increases neuron excitability).

But an increase in dopamine is going to cause more neuron excitability in postsynaptic neurons in some regions (those that have D1 receptors), and less in others (those that have D2 receptors). What then explains the fact that increased expression at all dopamine receptors can help modulate attention span?

I know that D3 and D4 are also involved, but they have to be either excitatory, inhibitory, or neutral.


texts: Do humans have chemosensors for nutrients or chemicals?

texts:
I'm reading about chemoreceptors on Wikipedia, and see that the typical ones are mentioned: taste, smell, CO₂.  I would like to learn more about the other kinds of chemoreceptors that humans may possess. I'm particularly interested if these can detect chemical compounds, or lack of thereof in food.

Here's an example:
Do omnivore mammals vary food preferences based on dietary needs?

  There's "rapid recognition of Indispensible Amino Acid(IAA) depletion in the rat brain's IAA chemosensor, the anterior piriform cortex (APC)"

Reading the article above, it appears that at least rats and birds can develop aversion to food that does not contain indispensable amino acids. This is done through chemosensors in the brain. Do humans possess any similar chemosensors?

Thank you for your input!


texts: $F_{ST}$ when considering a multi-allelic locus

texts:
Sewall Wright defined the $F_{ST}$ in a metapopulation as being:

$$F_{ST} = \frac{\text{Var}(p)}{\bar p (1-\bar p)}$$

, where $p$ is a vector of frequencies of a given allele and $\bar p$ and $\text{Var}(p)$ are the mean and variance of this vector.

For example, consider a metapopulation made of 4 subpopulations. The allele frequencies in these 4 subpopulations are p=[0.2, 0.5, 0.8, 0.3]. $\bar p$ is the mean of $p$ ($\bar p = 0.45$) and $\text{Var}(p)$ is the variance of $p$ ($\text{Var}(p )=0.07 \space$).

Question

Can we define $F_{ST}$ for a multiple allele locus? Or should $F_{ST}$ be defined for each allele independently?


texts: Estimation of cell count of E.coli culture

texts:
Can I get some help with an estimation of a cell count in a culture of E.coli cells if we assume we begin with $10^6$ cells, that they divide every 30 minutes and they are incubated for 12 hours?

I do not know how to do the calculation with a start number that is not 2, if it was it would just be $2^{24}$. But how is it done when the starting number of cells is $10^6$?

Is it $(10^6)^{24}$?

Thank you!


texts: How does different sensory stimuli differ in nerve signal?

texts:
Every day, we experience different types of sensory stimulus,  like heat, pain, cold, etc. However, in each case, the transmission of the stimulus to the brain through the neurones is carried on in the same way: through propagated depolarisation and repolarisation in axons, while through the release of acetylcholine at the synapses.

So, how does the different sensory stimulus differ if they are transmitted the same way? (I mean to say that how does the nerve signals differ for two different kinds of stimulus?)

Let's put the question simply:

How do two nerve signals originated from two different stimuli differ? If they do not differ, then how does the brain differentiate between different nerve signals if they are all alike? How does it understand what nerve signal carries what message?


texts: Some trophoblast excreting digestive enzymes in implantation

texts:
I found this paragraph in my study materials about implantation

Original

  Simplest trophoblast excretes trypsin related substances and embedding consists of 3 stages:

  The blastocyst (composed of cytotrophoblast and embryoblast) stick to the uterine wall
  Enzymes digest nische (little hole in the endometrium) to the functional layer and the blastocyst deepens in it. The nische is a closed and destroyed functional layer, in it tissue and blood is used for trophic (called a nischtrophic way of feeding)
  Implantation ends in 13½ day when the functional layer covers the blastocyst.
  Implantation normally takes place in anterior and posterior wall of uterus, sometimes in superior or fundus wall.

My suggestion for corrections

  Syncitiotrophoblast excretes Digestive Enzymes and embedding consists of 3 stages:

  The blastocyst (composed of cytotrophoblast and embryoblast) stick to the uterine wall
  Syncytiotrophoblast expresses digestive enzymes which dig a little hole (nische) into endometrium. The hole is usually filled with maternal tissue (so closed) and blood used by the conceptus for histotrophic feeding (nischtrophic way of feeding)
  Implantation should end in 13½ day when the endometrium covers the blastocyst.
  Implantation normally takes place in anterior and posterior wall of uterus between glands of the hypertrophic endometrium, sometimes in superior or fundus wall.

I cannot accept the phrase simplest trophoblast and the use of the words trypsin related substances. Really, how can you get trypsin without pancreas? I would not use the word trypsin although the enzymes may have some structural similarities.

How would you reformulate the paragraph?


texts:
I recently learned about Osteoid (the substance secreted by osteoblasts during intramembranous ossification), and I read that it was an "unmineralized organic component of bone."

Now, does this mean that Osteoid is un-calcified?? I don't know if I can equate unmineralized with uncalcified but I just wanted to make sure.


texts: Any simulations of four-winged dinosaur flight? (microraptors)

texts:
This week's podcast of the BBC's Science in Action includes a section by Rory Galloway (12:20 to 18:30) covering the Dinosaurs of China exhibit currently hosted by Wollaton Hal at the University of Nottingham, and includes an interview with curator Dr. Adam Smith.
The exhibit is of highly detailed dinosaur fossils from Liaoning, China where detailed feather structures were well preserved and have been analyzed in great detail.
One section caught my attention:

Rory Galloway: "The similarity between dinosaurs and birds was far more than superficial though. Eventually a branch of small, theropod dynosaurs evolved into the birds that fly around today. But curator Adam Smith says, if we concentrate on flight alone, it gets quite difficult to know exactly which branch of the dinosaurs actually became our birds."
Adam Smith: "Flight is really important and that’s why it evolves many times. Some of the earliest flying dinosaurs, such as the microraptor actually had four wings, not two."

The Wikipedia article on the Microraptor is quite long and includes a lengthy, technical discussion on just how these four wings might have been used. It seems that it is (currently) generally believed that these dinosaurs had the capability of powered flight, and that they could actually take off from the ground, rather than climb trees, jump, and simply glide.
This is with four wings.
There are many variety of insects with four wings and the two pair are used in a variety of different ways. But these dinosaurs are much larger, of the order of a kilogram.
Question: Have there been any complete simulations of the mechanics of four-winged dinosaur flight, showing how the wings would have been used to take off from the ground and gain altitude? A movie or animation of the coordinated flapping of the front versus rear pair of wings would be great. These days the numerical models and computing power are within reach, but it would still be a substantial effort, so I'm not sure if this has been done yet or not.
I'm assuming that this is not currently believed to be the branch of dinosaur that eventually evolved into modern birds, but it's a fascinating branch nonetheless.
below: from here.


texts: Can high energy photoelectrons damage cell membranes?

texts: I've read that in addition to ionizing radiation causing damage to DNA through direct absorption, but DNA can also be damaged through photoelectrons with enough energy.  The thing I was wondering is what kind of energy (in electron volts) would or might photoelectrons need to damage or penetrate the cellular membrane (like if x-rays excite photoelectrons outside of cells)?


texts: How does an increased amplitude affect nerve conduction velocity?

texts: My professor said that increasing the amplitude (the amount of depolarization e.g. depolarizing from -80 mV instead of -50 mV) leads to a greater conduction velocity.


texts: If DNA is more or less the same in all cells, and DNA is used to produce proteins from aminoacids, then do all cells produce the same proteins or are they specialised/controlled by something?


texts: What is known about the coding sequence of Factor H in the human genome?

texts:
Factor H is a protein coded in 20 domains.

My question is whether these domains form some kind of repeat cluster in the human genome. Basically, I'm interested in the coding sequence from an assembly point of view: Is the coding region fully resolved? Apparently there is only one copy of the gene per haplotype, but are coding domains maybe similar to each other or repetitive in themselves?


texts:
Is there anything special about not considering ear ossicles as a part of skull?

I could not understand the reasoning behind such  classification.


texts: Why is beta-mercaptoethanol often added to cell culture media

texts: Many protocols suggest that beta-mercaptoethanol is necessary for growing cells. It is a reducing agent but what does it mechanistically do for your cells. When would one not add it.


texts: I have recently begun using Folding@Home and I am curious how people are prevented from cheating the system. It seems to me that unless the final result is easily verifiable users could submit bogus folds in order to quickly gain credits. Is it in fact the case that the final results of calculating a protein fold are easily verifiable?


texts: What causes pain in an angina pectoris? Ok, heart muscles may lack oxygen, but what is the role of pain here? Is it being beneficial? I'd like to know the physiological process of induction of pain during hypoxia.


texts: What are the purposes of granulocytes in acute inflammation?

texts:
I heard the phrase

  Neutrophilic leucocytes are kings in the acute inflammation.

Neutrophils are granulocytes, while leucocytes are not granulocytes.
I think this statement refers to the fact that leucocytes have neutrophilic properties, instead of being neutrophils itself.

Acute inflammation players are, I think

Granulocytes, monocytes and leucocytes

while in chronic inflammation similar player but the main factor is macrophages so the phrase which I heard

  Macrophages are the kings of chronic inflammation.

I think granulocytes are related to the Healing and Proliferation.
Eosinophils for instance in the allergic responses of acute inflammation.
I think granulocytes are phagocytosed by the macrophages and this way spread their functions through macrophages around.
Probably, neutrophiles are attached to the leucocytes such that they spread their function through leucocytes (so called neutrophilic leucocytes).

Let's cover first this, since we can after understanding it go to the chronic one.
What is the purposes of granulocytes in acute inflammation?


texts: How are antibodies specific for a disease detected in the blood if everybody produces a different antibody for the same antigen?

texts:
To break the title down into parts:

There exist serology tests that detect the amount of an antibody (Ab)
against a specific pathogen/antigen.
Every human produces their own Ab for a specific antigen by
(relatively) random combination of different gene segments in their B
cells, until one that recognizes the pathogen is found and produced
in massive amounts.
One portion of every Ab is constant, whereas the portion that
recognizes the antigen is variable. Even for antibodies (in different
humans) that recognize the same antigen, albeit to a lesser degree.

What exactly does an antibody titer/serology test detect in the blood so that it can accurately measure the amount of antibodies against a specific antigen? I am assuming they use antibodies against the antigen-binding/variable portion of an antibody. But if the variable region differs from person to person, how can a universal antibody (to be used in serology tests) against it be generated?

Is the variable region not that variable, so that any lab-generated antibody against any functional antibody against a virus works well enough for an accurate measurement of antibodies against that virus? But even so the concept sounds hard to believe since even a single antigen can have multiple epitopes, and one person might have an Ab for epitope 1 of antigen X, while the other would have an Ab for epitope 2 of antigen X. And they would still be immune to the same virus, while a universal Ab titer test for the virus would be unable to detect antibodies from one of them.

Do they perhaps employ multiple lab-generated antibodies against most of the possible variations of human-generated antibodies in the tests?


texts: Can the mating of a couple with Rhesus positive and negative blood types result in miscarriage?

texts: Can the combination of $+ve$ and $-ve$ blood groups of a couple be a cause of miscarriage in pregnancy?


texts: Is there any difference in terms of personal healthcare between complete DNA sequencing and SNPs genotyping?

texts:
There are several companies (most notably 23andMe) providing SNP genotyping for individuals claiming that there is no sense for individual in obtaining full genome sequence since only small part of it could be interpreted.

While this agrees with my understanding of the subject, I wonder whether there could be any use to perform full sequence of one's genome for means of personal health care?

The only effect I recall which affects individual's health and could not be caught by SNP genotyping is DNA methylation, but complete sequencing procedure does not detect it either, as far as I know.


texts: In cell division, are daughter cells identical?

texts:
I understand that after a cell replicates, there will be two daughter cells instead of one. But wouldn't one of them be the old cell that created the second one?

The old cell having gone through G0, interphase, and mitosis and after dividing wouldn't it be somewhat different from the new cell (the old cell's telomeres having shortened, having already undergone the cell cycle and so on)?


texts: Does germinal centre interaction with environment contributes by any means to the heterogeneity of the SHM-resulted antibody repertoire?

texts:
B-cells undergo a process of rapid mutagenesis and division which is followed by selection. Somatic hypermutation (SHM) produces many different antibody (Ab) genes that can potentially be useful against a co-evolving pathogen. SHM occurs in structures named germinal centres (GCs). Now, my question, as a student, is:
Are SHM and other processes in GC the only factors contributing to the huge variance of antibody genes, or some environmental factors directly influence this variance? (create, destroy or even select some Ab variants) For example, is there any chemical factor that can affect the SHM or selection process with the results of addition, loss or favouring some of the Ab variants produced in GC?


texts: Activated carrier molecules and their relationship to enzymes

texts: I am reading Molecular Biology of the Cell, and one thing I don't quite get is the difference between an enzyme and an activated carrier molecule. I understand that enzymes lower the activation energy for a reaction, and in that sense speed up the rate at which a reaction occurs. I also understand that activated carrier molecules act as a source of energy that can drive unfavorable reactions (like anabolic reactions) forward. But I still don't quite grasp the exact difference. I was wondering if someone could shed some light on this.


texts: How does gene expression work in an adult organism? Is everything encoded everywhere?

texts:
The color of a person's eyes are genetically predetermined. If I knew how and in which gene(s) colors are encoded, I could change these genes in the ovary and sperm and thus change the eye color of the new human being. I only had to work on one or two cells.

What would I need to do to change the eye color of an adult human? Manipulate the genes in all body cells? Or would a limited number of cells suffice (e.g. those in the eye)?

Eye color is just an example. Your answer does not have to deal with this trait.


texts: Probability of carrier for recessive trait given parents are carriers and sister affected

texts:
I'm trying to understand more about inheritance of an autosomal recessive trait that runs in my girlfriend's family. How could I start looking at this?

My girlfriend's sister, C, is affected with a recessive trait. Her parents, A and B, are confirmed unaffected carriers. Am I correct to assume my girlfriend, D, is a carrier with probability 50%? Or must I take into consideration that we know the state of C given she is affected.

Furthermore, if I (E) have a child with my girlfriend, what is the probability that our children are either carriers or affected? My carrier status is unknown.


texts: I want to start learning Neuroscience. Can someone give me an advice about a nice textbook for beginners? I'm particularly interested in the application of Neuroscience in programming and AI development. Thanks in advance.


texts: Why does getting certain chemicals in cuts hurt?

texts:
More specifically, shampoo. What are the mechanics of detecting a noxious chemical stimulus in terms of which receptors recognise what, how do they do it, and how is this information relayed to the nerve cells?

Why is the pain (and so signal, I presume) larger if one is having a hot shower at the time?


texts: Evolution: How could all useful traits evolve simultaneously?

texts:
I have a basic question about evolution, for which I never found an answer. I understand how evolution works if we focus on one specific organ or trait. With each generation, some organism is more likely to reproduce, so the trait that leads to success gets more frequent. My problem is understanding how all the traits can evolve simultaneously.

Looking back to our ancestors, we evolved many different kinds of adaptations (in unrelated areas like eyesight, kidney efficiency or a healthy fear of predators, digestion of certain nutrients, balanced walking etc.).
Natural selection can only work with what's there, so mutations are important. But if  mutations are rare, it seems unlikely that many (thousands of) properties of organisms get improved in a single generation. You'd need to get very lucky to randomly improve all the genes responsible for it.

So, if we look back to our ancestors again, did they just improve on a single or a handful of traits in each generation? In that case we would need hundreds of generations before we have improved somewhat on each "front". By then, the other properties could "drift" back to a not-so-advantageous version. (This was supposing that each generation improves on a random trait, as opposed to long sequences of generations each improving on the same).
Or were there always some super lucky organisms that randomly got an improvement on almost all different traits? But just having some of those super lucky ones is not enough. The good traits don't guarantee success, just improve the odds. So we'd need many very lucky ones in each generation.

Has anyone calculated or simulated how the adaptation for many different traits can happen simultaneously?


texts: Why do we have to exhale (or inhale) in order to speak?

texts:
Every time we speak, sing, or make any other kind of advanced noise with our throats, we exhale, or to put it that way, blow air through our throats. Why is this required? After all, speakers do not need any air blowing through them, they simply vibrate the air and create the vibrations (sounds) they're supposed to.

Why can't humans create (intelligible) sound just by having an organ that vibrates the air around us? Also, are there any animals that can? (None that I can think of at least). Would it be an evolutionary gain, or just rather pointless?

PS:
Obvoiusly we can clap out hands and the like, but that's not what I'm talking about.

Edit: The question is not about exhaling/inhaling, but rather why we need airflow in the first place; why we cannot use a mechanism similar to that of speakers.


texts: Does the cranial dura consist of the periosteum? and if not, then is there a mistake in my textbook?

texts:
My textbook (Neuroanatomy an illustrated colour text) states that:

  The spinal dura and much of the cranial dura are separate from the periosteum, which forms the inner lining of the surrounding bones.

However, as far as I am aware the cranial dura has two layers, one of which is the outer periosteal layer or the periosteum, so I'm not sure why this is mentioned separate to the cranial dura.
The textbook later states that:

  At certain locations, however, such as on the floor of the cranial cavity, the dura and periosteum are fused and the cranial dura is tightly adherent to the interior surface of the skull.

This would make sense if they were referring to the pericranium, but the first quote suggests that the textbook is referring to the outer periosteal layer (or the inner periosteum).

Please could you shed some light on this. Thank you.


texts: What is this strange sea creature we found on the beach?

texts:
We found this on a beach in North Devon, UK. I've never seen anything like it.
There's a yellowy-ball in the middle with 5 pointed shells attached to it, each of which seems to have a single "leg" coming out of the bottom. It almost looks like it's 5 separate creatures feeding on something, but they're pretty firmly attached. Perhaps it's some sort of egg-sac that they're growing from?
Does anyone know what this is?


texts: How many gigabases of DNA are there on earth?

texts:
The human genome is about 770 MB, the C. elegans genome is about 100 MB, the yeast S. cerevisiae is about 12 MB. Different other genomes have been sequenced: how many GB of genomic DNA we have now?

Let say we would like to make a Noah hard-disk ark: how much space would it take to represent the genomes of all known species on earth? There is a way to provide an estimate?

I'm also interested in the total biodiversity: for instance, if two species each have 1 GB genomes and have half of their DNA in common this would count as 1.5 GB.


texts:
There's a small insect that seems to enjoy residing near trees and takes blood meals. The pain is sharp, comparable to being stung by a wasp.

I'm located in Serbia, Eastern Europe, bordering Hungary and Romania. It's currently August, warm and very moist from the grass being regularly sprinkled.


texts: Difference between Bioscience and Lifescience

texts: Are bioscience and lifescience the same things? I am a little bit confused about it. If not, then what is the difference between the two?


texts: What is the biological significance of finding palindromes in DNA sequence?

texts: I found a function called palindromes in Matlab that finds palindromes from DNA sequence. Now what is the biological intention behind incorporating this function? What the biological significance of finding palindrome in DNA sequences?


texts: What are those patterns found on the surface of wooden furniture? Are those growth rings of trees?

texts: This image can give a suitable example for the above question.


texts: I want to use some yeast mutants to conduct gene functional analysis, and the gene was isolated from plants. Can anybody give me some information regarding the websites or agencies from which I can purchase the yeast mutants?


texts:
I found a formula online which explained the reaction which occurred in the anode chamber of a microbial fuel cell but there was a typo

$\small NADH + Ferredoxin_{(ox)} (NADH-Ferredoxin\ Oxidoreductase) \longrightarrow NAD^+ + Ferredoxin_{(red)}\ \
Ferredoxin_{(red)} (Hydrogenase)\#61614;Ferredoxin_{(ox)} + 2H^+ + 2e^-$

I attempted to correct it but I'm not sure if I'm right could you check this and see if it's correct?

$\small NADH-Ferredoxin\ Oxidoreductase \longrightarrow NAD^+ + Ferredoxin_{(red)}$

$\small Ferredoxin_{(red)} \longrightarrow Hydrogenase + Ferredoxin_{(ox)} + 2H^+ + 2e^-$


texts: Are cytotoxic (killer) T-cells always present or are they only produced during a cell mediated immune response?

texts:
The book I'm studying says the following
"During a cell mediated immune response, the release of IL-2 by helper T-cells is resposible for stimulating the production of Cytotoxic T-cells, which have receptors that match the anti-gen of the infecting pathogen."

I'm not exactly sure if this is impliying that cytotoxic T-cells are only produced and present during an immune response or not, since I also have an older version of the book that simply says "the IL-2 released by helper T-cells activates cytotoxic T-cells" which seems to indicate that they are normally always present, but just inactive


texts: How to identify whether something is in linkage disequilibrium?

texts:
If the following loci indicated the presence of an SNP in flu strains, is Locus 2 and Locus 3, which are located 10 bp apart in linkage disequilibrium?

"When alleles and molecular
markers are associated with each other at a frequency that
is significantly higher than expected by random chance, they
are said to exhibit linkage disequilibrium" Brooker's Genetics

Both loci seem to be linked, but how do I determine if it is significant enough to be considered in disequilibrium or not.


texts: Why are the other bases not used for RNA capping and tailing?

texts: Why does the addition of a 5' cap and that of a 3' tail involve guanine and adenine respectively? Why aren't any of the other two bases added to an mRNA to protect its ends or act as a signal to transport it to the cytoplasm?


texts:
I live in Africa (DR Congo). Here we have these insects that look like ants. They appear between May and June.

These insects give severe damage if crushed on the skin. They contain something like acid that burns the skin. I saw many people wounded by them.

So I would like to know what these insects are, and whether they can cause death if swallowed? Can someone point me to where I could learn more about them?

PS: There are no forests near where I live.

Edit:

The insects appear at the end of the rain season (April, May)  and right before the dry season (May, June).
Attracted by (neon) light. I think they fly only once then drop their wings (not really sure).
Can be found in homes (houses).
Can burn skin like acid.
It measures approximately 5 - 8 millimeters (not sure. can't find one right now).
Crawls fast with its tail upwards (don't know how to describe else, see image).
Solitary animal.


texts: At which temperature is the Tick-Borne Encephalitis Virus destroyed? If there is no data specifically for TBEV, is there any data for typical temperatures at which other Flaviviruses / Flaviviridae / other similar viruses are destroyed? (Or if there's nothing specific at all, then viruses in general?)


texts: Please explain what a gene isoform is in lay terms?

texts:
I am a physicist by training, however I am now doing computational biology research. I know what genes, DNA, proteins, enzymes, introns and exons are.  I sort of understand how DNA is used to create RNA, which is used by ribosomes to manufacture proteins.  That is the extent of my biology and genetics knowledge.

So, could someone explain what a gene isoform is in lay terms?  There is a related question here and wikipedia has an explanation.  However, there is a significant jargon barrier for me.


texts: What organisms are Chloroperoxidase enzymes found in?

texts: Are they found in humans? I'm wondering because they display a structural similarity to glucose-6-phosphatase, which is an important enzyme in gluconeogenesis.


texts: Why do you need you room dark for melatonin release?

texts:
There is a light pollution movement that says lighting at night obstructs melatonin production. They say:

  What makes you fall asleep are changes in the level of the hormone
  melatonin circulating in your body. During the day, light stimulates a
  part of the brain. This brain part (known as the suprachiasmatic
  nucleus) tells the pineal gland to decrease the melatonin level when
  it is light out and to increase it when it is dark. The brighter the
  light, the bigger the decrease and the darker the dark, the bigger the
  increase of melatonin. By making your days lighter and your nights
  darker, you can improve both the quality of your sleep and the amount
  of time it takes you to fall asleep.

and recommend all kind of protection against the light,

  Dark Nights: Make your nights as dark as possible. Draw the curtains,
  close the shades and keep the lights off. Try a sleep mask if you
  can’t get eliminate enough light. The darker your night, the quicker
  you will fall asleep.

Do I sense the light by the whole skin surface or only open eyes? If you sense by eyes, which are closed during the sleep, then what is the problem?

In other words, the question is: is the sleep mask sufficient for melatonin secretion or you need to cover the skin?

update What if I close only one eye? I tend to do this when the blinding sun shines. Does such light eject melatonin?


texts:
What happens if one looks directly at infrared LEDs? Sometimes I see this kind of LED at night as red dots and I'm also courious about it.

I was wondering what would happen if one looks directly to these LEDs, because we see them everywhere like in remote controls, CCTV cameras, sensors, etc.

What is the difference between infrared and visible light to our eyes?
(I mean why is it impossible to look directly to visible light while we can look to infrared?)

LED: Light-emitting diode


texts: Can the mutation rate vary for individuals of the same species, growing in similar environments?

texts:
Suppose we consider several populations who originally inherited their genome from the same ancestor, and that we put for a few thousands generations in similar environments.
Could the mutation rate vary between the different populations or within the same population, but between different time points?


texts: Is tunneling of a proton in our DNA a cause of mutations?

texts: Our DNA strands are tight together by hydrogen bonds. Can the proton of Hydrogen tunnel to the other complementary strand, and by this during the replication bind to a different/wrong nucleotide, causing a point mutation?


texts: Do exon deletions in C.elegans mutants necessarily result in nonsense mediated decay of the transcript?

texts: I am trying to write out my research proposal about a project in C.elegans. There are multiple mutants of the factor that I want to study, each with different mutations. I know that a mutation that abolishes the promoter and transcription start site of the gene will most likely be a null mutant. But what about strains that have internal deletions? For example, if I were to generate mutants missing specific exons such that there was a predicted ORF for the gene product, is this transcript automatically targeted for nonsense mediated decay? I was told that this was a C.elegans specific process (deletion mutants are often protein null?), but I am having trouble finding this information.


texts: Does leaving land alone actually help nature conservation?

texts:
I like nature conservation - the idea of creating protected areas where nature lives on its own and wilderness is "created" like that. Is is possible to raise the natural value of land only by leaving it on its own - I mean in the way that humans do not touch the land in any way (buildings, roads etc.)?

I know about some "private" protected areas in Europe, where NGOs thought this piece of land should be protected but the authorities failed to do so, so they bought the land and took care of it themselves (restricted public access to help conservation, removed invasive species etc.)

I wonder what does it take to correctly protect an area - is it OK to leave the land alone and never touch it again or is it necessary to take care of it somehow. I mean things like invasive species (I can imagine the normal "unprotected" nature is full of them) like various types of grass, invasive animals etc. I can imagine this may be largely location dependent (some parts of the world are more influenced by humans than others). My location is the Czech Republic.


texts:
I heard in this interview of Jill Cook (tendon researcher) on https://youtu.be/GKkSp-TlofI?t=230:

  Tendons talk to you 24 hours later. So what happens if if I put load on a tendon today, it will tell me tomorrow it's been happy with the load.

Why does it take 24 hours for tendons to give feedback on whether the loads they received were excessive?


texts:
I am very new to biology,  currently just a student. Recently I learned of the electron transport chain used in cellular respiration. This  got me thinking. At the end of the chain, the electrons are joined with hydrogen and oxygen forming water.

It  seems that  all cellular activity (that  I've learned about) is very careful to bind any electrons to some byproduct molecule after using them. Thus I get the impression that free electrons in a cell are dangerous. I asked my  teacher about it, but he wasn't sure. So now I am dying to know, what would be the consequences of allowing  a free electron to float about a cell?


texts:
I've been referred to here from https://philosophy.stackexchange.com/questions/8052/why-are-things-conscious. Could you guys help out? Here's the question:

What is the reason for animals or more general entities being conscious? How did this evolve? What is the advantage?

I'm aware of ideas that consciousness is merely a illusion, however I find them less than convincing. The counter-argument would follow the line "if consciousness is an illusion, who has the illusion and more importantly why?". Additionally I believe that consciousness is a bare empirical fact. Even more, it is the basis for empirical thought. That "consciousness is an illusion" is not a good idea has been discussed by e.g. Searle (a video can be found here http://www.youtube.com/watch?v=yCii726A4Jc)

So what are good explanatory models for consciousness?


texts: I am trying to extract information about SNP data from the FTP server of NCBI. Could someone please explain to me how the directory is organised? There are many many files and folders and I can't figure which contains what. Is there one file which explains the organisation of the ftp site properly? The NCBI help manual did not give much help beyond helping me find species of interest.


texts: Difference between 'fitness' and 'fitness effects'

texts:
Term 'fitness' is pretty obvious, but, often 'fitness effects' is commonly used in many research articles in the field of evolutionary biology.

I suspect that 'fitness effects' has a different meaning than just 'fitness'. I found that it's really difficult to find the distinction between the two terms just by googling.

So, if some expert in the subject is reading, please clarify.


texts: Possible to Gain More Weight than the Food You Eat

texts:
I was wondering if it's possible to gain more weight than the mass of the food you eat. At a first look, this is impossible because of the principle of mass conservation, but are there other things to take into consideration?

For example, fat contains carbon. Does the body use the carbon we breathe to produce the fat necessary to store any energy we don't use? And a relevant question: how efficient is human fat at storing energy, compared to what humans normally eat?


texts: Is it possible to add a new sequence to a blast database without recreating it from scratch?

texts: I have a new sequence and I want to add it to a pre-constructed BLAST database containing other sequences. The makeblastdb help does not give any hint on this regard.


texts: Selection marker for a cytoplasmic vector that works at low expression levels?

texts:
I need to express a selection marker on a plasmid in human cells (e.g. HEK293). However, I am using a cytoplasmic vector derived from a non-human virus with its own mechanism for transcriptional initiation. This means that the expression level of any protein marker will suck: low copy number, very weak promoter, unstable transcripts - these are things that I cannot change in this precise biological context.

Most selection markers (for instance KanMX) come with their own black-box promoter and so I do not know whether they rely on a high number of proteins being produced.

What would be a marker most likely to be selectable despite a very low expression level? I could not find any resource comparing the protein copy numbers of classic markers.

I need to be sure that the cells that cannot survive the selective pressure died because they did not have the marker, and not because the marker was too weakly expressed to protect  cells that have the marker. The standard approach would be to use a regular antibiotic selection and just work with lower concentrations of antibiotics but the number of false positives would most likely be too high.

I can manipulate the host cell to some extent, so I can use antibiotic selection but I can also complement a conditional deletion of an essential gene (auxotrophic marker or non-metabolic genes).


texts: Evolutionary term for multiple, related adaptations

texts:
Is there a term in biology for when adaptations are compounded on (or by) other adaptations?

One example in whales: the tail flukes, reduction of rear limbs and development of the blowhole were all part of a number of shifts that aided the transition from land to water. Is there a term, like chain shift, for that?

Also with humans, encephalization led to pelvic adaptation for larger infants.


texts: Finding diploid neanderthal alignment data, looking for ambiguity codes

texts:
I'm using Neanderthal alignment data from here: http://www.eva.mpg.de/neandertal/draft-neandertal-genome/data.html

Specifically, the .bam files. I would like to find alignments for neanderthal sequences to human genomes that state ambiguities (such as M or R). However, the data from that site does not have the ambiguities. Is there a way to find such information? Or are there no ambiguity codes in neanderthal alignments?

My goal is to compare diploid neanderthal sequences to diploid human sequences. How do researchers typically deal with this given the limited data they have for neanderthals?


texts: Does the radula sac in any mollusc serve a purpose other than sheathing the radula?

texts:
According to Barne Gat Shellfish:

When not feeding the radula is retracted into this chamber which protects the mouth from the sharp teeth of the radula.

Does the radula sac serve any other purpose?


texts: Is it possible to kill parasitic worms by intoxicating oneself?

texts:
I've heard of parasites that can live in the human body and do a lot of damage to the host. There are even safer forms of worm-like parasites inside the intestine, but some parasites can live in the blood vessels or even in the brain or eyes.

Parasites are, in my opinion, the most disgusting creatures there are, so I wondered if they could be killed with intoxication.
Would it be possible to get rid of worm parasites in the blood by increasing the amount of alcohol in the blood to a level that humans can tolerate but parasites can't?
Could you also eliminate brain parasites with hangover-related brain dehydration?

That the dead parasites remain in the body may not be good or advisable. In addition, eggs, which are usually a little more resilient, should rather be removed from the body by antibiotics or proper medication. But is it at least theoretically possible to do something with alcohol against parasites?


texts: how origin of koi carp is different from goldfish

texts: where did koi-carp originate? how are they different from goldfish? Wikipedia say that goldfish originated by genetic mutation but what about koi-carps?


texts: Similarity between a heart attack and a spasm

texts:
When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work.

The heart is basically a muscle working constantly to create a sinus rhythm. As I understand it, one can get muscle spasms in any muscle (correct me if I'm wrong). If so, then couldn't someone get a muscle spasm in a part of the heart muscle that disrupts the sinus rhythm and causes chaotic signals? Thus causing a spasm throughout the muscle.

When one is having a heart attack, does the electric shock used cause a dramatic and fast 'stretching' of the heart muscles allowing the heart to get over the spasm and back to normal rhythm? Could something else, like an ElectroMagnetic Pulse be used to 'stretch' the heart muscles away from the spasms?


texts: I managed to photograph a lizard in Haruvit Forest, Israel. I would like to know - what lizard species is this? Size appr. 20-25cm


texts: Why do we experience temperatures below 37 degrees Celsius as 'hot'?

texts: We always prefer to be in 20-25° C, although our core temperature is about 37°? Why is our skin temperature lower than our core temperature?


texts: Why can't sodium butyrate be delivered orally in humans and other mammals?

texts: I think I know why -- bioavailability problems but since I have no firm evidence to support this theory I thought I would ask the biology stackexchange community for their input. I'd like some firm bioavailability data of sodium butyrate in mammals, preferably humans.


texts: Can tubular secretion regarded as local hormone?

texts:
Tubular secretion is : The process in which ions and other waste products are transported into the distal tubules of the nephron.

can it be regarded as local hormone??


texts: Alternative conditions for Liquifactive Necrosis

texts: A person is beaten on the head hard enough to swell the whole front part of the head. The body is thrown into the river and recovered after about 36 hours. Is this condition enough for liquifactive necrosis to occur? If not, what could have caused it?


texts: Has there even been a clinical study where healthy volunteers consented to be infected with a pathogen?

texts:
I am curious if there has ever been a (modern) clinical study where a healthy volunteer was purposefully infected with a pathogen in order to test the effectiveness of a therapeutic or preventative measure (like a vaccine)?

If not, would the FDA allow for ethical exceptions in cases where there is an extreme case of urgency (like in a pandemic)?

Obviously these would be willing volunteers who signed waivers, etc. So Nazi experimentation, the Tuskegee trial, and other studies without total consent from the participants wouldn't qualify here.

Edit: Self-experimentation wouldn't qualify here either because the bioethics of self-experimentation are different than testing on others.


texts: Is Batesian Mimicry a form a parasitism? To what extent is the species with real defenses harmed by the defenceless species?

texts:
It seems like Müllerian mimicry would be an example of mutualism because both species would end up being eaten less by predators that only have to learn one pattern of warning symbols. But to what extent is Batesian mimicry a form a parasitism? It seems like predators who ended up consuming the harmless species would lose some of their conditioning to not eat prey that resembled it, thus harming the species that is actually protected.

How often might this happen in ecosystems where Batesian mimicry is present? Does the presence of a similar unprotected species cause the protected species to be a more common target for predators?

Difference between Batesian and Mullerian mimicry on wikipedia


texts:
[This is one more post in my growing "X for dummies/idiots/morons/etc." series.]

I've been enjoying Provine's The origins of theoretical population genetics for the last couple of days, but I must confess that I find his description (on pp 127-8) of the logic behind Sewall Wright's (and W. Castle's) selection experiments with "hooded rats" about as clear as if it had been chiseled in Linear A...

Which is really bumming me out, because I'd love to understand these experiments.

Does anyone know where I can find a description of these experiments aimed at those with only a very limited grasp of classical genetics?  (I took a graduate-level genetics class a billion years ago, and I did not find it easy.)


texts: Does PCR amplification affect microarray or DNA biosensor results?

texts:
I've noticed that PCR amplification is commonly done before analyzing the DNA sample with microarrays or biosensors.

However, won't amplification biases or errors mess up the gene expression profile results you get from a microarray? Secondly, does that mean amplification only allows you to get qualitative information from say an electrochemical biosensor? (rather than actual quantitative information about DNA concentration)


texts: There is a lake in Siberia called Lake Pustoye. No life exists in the lake. There are no fishes and no plants and even trees around the lake die . No birds even visit this lake .The lake even has bubbles in it like champagne .The water has been tested and there is nothing in the water that makes it harmful to life.  It even tastes like champagne and yet life cannot exist in it .Fish were introduced into the lake but they quickly died off . So why can't any life form survive in this lake ?


texts: Why do grapes not pea shrink when placed in strong sugar solution?

texts:
I tried an experiment. First, I placed grapes in pure water(hypotonic solution). The grapes burst because of endosmosis. Then, I placed new set of grapes in strong sugar solution(fully saturated) but they did not shrink. And then when I placed it in strong salt solution(fully saturated), they did shrink a little. Why does this occur?

How is this possible?


texts:
"Formation of Rh  antigen is controlled by dominant gene(R) and its
  absence by recipient gene(r).People having this antigen with genotype
  (RR or Rr) are called Rh positive and those whose blood is devoid of
  it with genotype (rr) are called Rh negative. About 85% in world are
  Europe and 97% human being in India are Rh positive."

My questions are:-

Which factors result into dominance of gene(R) and  absence of recipient gene(r)?

With difference seen in %ratio in India and Europe, can it be concluded that environmental factors affects it.?


texts: Is there a surface or body cavity that does not have epithelium?

texts: Is there any surface in the (human) body that is not covered with epithelium?


texts: Correlating Ki values of pesticides to bacterial growth

texts:
Four pesticides P1 to P4 are reversible inhibitors of an enzyme E that
  is essential for the growth of a bacterium B. Their Ki values are
  given in the table below. Each of these four pesticides is used in
  four geographically different regions R1 to R4. The residual
  concentrations of these four pesticides in the respective regions are
  also shown in the table below:

  Which pesticides will be able to inhibit bacteria ?

My question : I know that Ki shows the binding affinity. So, how is that related to residual concentration ? How can I deduce whether it will kill the bacteria or not ?

Unrelated question : Is it acceptable to use the word pesticide here ?!


texts: Why do bacteria use formylated methionine in the initiator tRNA, while eukaryotes do not?

texts:
Could anyone suggest an explanation for the evolution of this trait in bacteria? Does it confer any advantage?

It is also exploited by immunity receptors of some eukaryotes for the recognition of bacteria.

In the literature I was only able to find a paper suggesting a possible role in signalling for protein degradation.


texts:
Is it possible to spray stem cells on fully grown skeleton to get fully grown humans?

Currently, just read about recent advances, and wondered if something like this is possible.


texts: What limits the maximum spacing of Nodes of Ranvier and which organisms tend to have the widest gaps?

texts:
Assuming that a longer distance between gaps in the myelin sheath is beneficial for an organism due to the increased propagation speed, what is the limiting factor in determining the maximum spacing between nodes?  I have previously encountered the analogy of the Nodes of Ranvier as forming a circuit between themselves and the previous node in order to pass on the action potential, which leads me into thinking that it is simply electrical resistance that is the cause however I assume the analogy is an over simplification and would be very interested in any alternatives.

Also, is there a significant variation in node separation between organisms?  Which organisms have the greatest gaps?


texts:
I just finished an immunofluorescence experiment and I'm wondering what went wrong. The tissues seem dimmer than they should be.

One mistake I made was: I completed the antigen retrieval step, in a 90 degree sodium citrate bath for an hour. The next step is to cool the tissue in ice for 8 minutes before washing. I forgot to cool the tissue, and just put it straight in the wash.

Could this rapid temperature change have affected my results? How important is this step?


texts: How can you identify if a person is homozygous for a certain allele?

texts:
I've been thinking about starting a small private research project. In this project I need to find out whether a person is homozygous for a certain allele. The reason for this is that I'm really trying to find out whether has a mutation that makes him/her not produce this chemokine. Thus I need to identify in an easy way which people are "normal", which people have the mutation in one chromosome, and which people have the mutation in both. About 1% of the population have the mutation in both chromosomes.

A primer would AFAIK not be able to differ between the heterozygous and the "normal" people.

Do anyone know how to approach this?


texts: At what temperature do human bones disintegrate?

texts:
I know, the human skin can get damaged as quickly as 2 seconds, when exposed to temperature above 80 Celsius.

However, what about human bones, say the skull?

For example, when you cook a meal, at great temperature, the chicken bones, still stay hard and intact, that's why I am asking.


texts: What could cause a forest of bent trees?

texts: While hiking on the northern Idaho-Montana border, I encountered a large area where virtually every tree is bent at the base in the downhill direction.  Only the very largest and very smallest trees are straight.  What could cause this?


texts:
Is apoptosis a part of cell division?
Can apoptosis occur if DNA is damaged beyond repair?


texts: Do mutations in one bacterial strain have the same effect in other strains within the same species?

texts: I would assume so, since they are the same species after all. I am asking this because I am doing a bioinformatics project for school and I cannot find any protein mutations for the specific bacterial strains that my department has managed to isolate. The proteins I have identified as stress proteins are within their genomes, but there is no known mutations I have found while perusing the literature. Mutations for these proteins are present in other strains though. Any help would be greatly appreciated.


texts: nontechnical understanding of a mammalian expression system

texts:
I just started working as an intern in the pharmaceutical industry. My background is in economics and I have pretty much zero knowledge of biology/chemistry. I am trying to build a basic understanding of some of the products I work with to better understand their place in the market. One (the most important) such product is a mammalian protein expression system. My questions are the following:
As I understand it the "output" of such a system is a protein, the "input" is DNA and the system itself is a cell, is this correct?
In the context of producing pharmaceuticals, would this system be used primarily for R&D, manufacturing or both?
I have read that an expression system consists of host cell lines, vectors, media and know-how. Would it be possible to explain in layman's terms what each of these elements is, and how they fit together?
Thanks


texts: Have anyone used realtime PCR, is that the plate for realtime PCR is one-time using or not ? Otherwise how to clean the plate after reaction to prevent wrong result in next time using ?


texts: Any pros and cons? One puts the test substance in sterile discs, while the other one puts it directly into wholes in the agar. Any thoughts?


texts: Change Genbank entry date with Biopython

texts:
I can create a new Genbank record in Biopython with the following code:

from Bio import SeqIO, SeqFeature
from Bio.SeqRecord import SeqRecord
from Bio.Seq import Seq
from Bio.Alphabet import generic_dna
from Bio.Alphabet.IUPAC import IUPACAmbiguousDNA

my_sequence = "ATAGGGACUCATAGATA"
my_record = SeqRecord(Seq(my_sequence, IUPACAmbiguousDNA()))
my_feature_location = SeqFeature.FeatureLocation(2,5, strand=1)
my_feature = SeqFeature.SeqFeature(my_feature_location, type="CDS", id="Cre")
my_feature.qualifiers["foo"] = "bar"
my_record.features.append(my_feature)

print my_record.format("gb")

The corresponding genbank file then looks like:

LOCUS       .                         17 bp    DNA              UNK 01-JAN-1980
DEFINITION  .
ACCESSION   <unknown id>
VERSION     <unknown id>
KEYWORDS    .
SOURCE      .
  ORGANISM  .
            .
FEATURES             Location/Qualifiers
     CDS             3..5
                     /foo="bar"
ORIGIN
        1 atagggacuc atagata
//

How can I change this bit UNK 01-JAN-1980?


texts:
Let me start by saying I have never used a microscope outdoors, and in general I have never owned a microscope nor used one regularly.

However, I am currently developing and organising some activities for children, to be carried out in a woodland. I thought it would be really interesting to use a microscope to analyse and compare different samples: leaves, insects, etc. In a word, to do some "field microscopy" (I googled that, but doesn't seem to be a popular expression).

Is it possible?
Is it easy?
What type of microscope should I look for? We have quite a bit of funding, so feel free to suggest anything.

Thank you very much.


texts: Do evergreen trees have higher densities of stomata to compensate for retaining leaves?

texts:
According to literature (Walls-Thumma), evergreen trees have less stomata on their leaves (than deciduous trees) to limit water evaporation.

Does this mean they have less less stomata in total, or do they have stomata on the adaxial surface that compensates for the smaller amount of the abaxial surface (in comparison to deciduous trees?).
Thanks!


texts:
many papers I read mentioned "RNA-seq data". While searching for the meaning of this word, I could not find any layman's definition.

As far as I understand, RNA-seq data is the complete RNA information in a cell (or all of the cells) of a species that is extracted at a certain time.

Am I correct with this definition? If yes, does this mean that by extracting all the RNA information ones knows all the RNA sequences in that species (like AUGGUCAUCAG....)? Or does it mean I have the RNA, but not the sequence?


texts: Does food grade diatomaceous earth contain mercury

texts: Not sure if this is the right site to ask this question, but since diatomes are or once were biological creatures it seemed to fit this one more than any of the others. I have been supplementing my food, and my cats food occasionally, with food grade diatomaceous earth which is supposed to be healthy and good for bones, teath, skin, hair and cell growth among other things, it is inhert & has no known side effects, its is used regularly as a cattle feed additive & also as a pesticide or anti-parasite treatment to kill worms, fluke and other critters.. I only started doing this as a supplement as i do not generally eat alot of vegtables or fruit & am more of a snacking person.. However I just seen an article that say's beer, wine and many other beverages contain mercury as many of them are filtered using diatomaceous earth (Which pressumably would have to be Food Grade). If there are any minerologist/biologist's is this true? Where does the mercury come from? is it safe? Can the human body filter this out?


texts: How long might a tick be on a body before biting?

texts: I understand that a tick must be attached for roughly 24+ hours before presenting a danger of transmitting Lyme Disease. However, I am wondering how long a tick might be on my body before actually attaching itself to me.


texts: Evolution, What would the first plants have been like?

texts: I am curious what the first plants are thought to have been like, what they may have evolved from, and how much earlier (or later) than animals they are thought to have moved to land, if they even started in water like animal-life?


texts:
I imagined that typical cells and viruses could have very different physical properties or reactions to mechanical stresses, which makes selective targetting possible. For instance, some  major differences between viruses and animal cells:

Difference in size/mass
Difference in elasticity (lack of cytosol in virus)
Difference in structural composition results in a different reaction in response to different vibrational frequencies

Preliminary search found something related to microwave absorption induced oscillation mode fracturing airborne virus, taking advantage of the (structural) core-shell charge separation in virus (not sure if I described the principle right, to be honest). However, though looks exciting, it is more like a disinfection rather than a treatment method. So the question goes: Has there ever been an approved viral infection treatment method based on the physical/mechanical properties of virus?


texts: How does botulinum toxin enter the blood stream from the digestive tract?

texts: To my understanding, large polypeptides such as botulinum toxin cannot pass the intestinal lining intact. How, then, can it enter the bloodstream and cause botulism poisoning?


texts: Why does the pulmonary artery have higher glucose concentration than the pulmonary vein?

texts:
If the pulmonary artery have higher glucose concentration than the pulmonary vein, does it mean glucose will be consumed during gas exchange?

That confused me because gas exchange is something like diffusion and shouldn't consume any glucose


texts:
Do butterflies (insects) sleep, and if so, where??

I have googled for information but didn't get an exact answer.


texts: Literature that demonstrates organisms have a competitive advantage in numbers

texts:
I'm studying two bird populations that are competing against each other for a resource: Population A and Population B.

Population A is present in much higher numbers than Population B, and as a consequence, I think that Population A has a competitive advantage over Population B.

I'm looking for literature that demonstrates that when one population is present in higher numbers than the other population, the population present in higher numbers has a competitive advantage. Can anyone point me in the direction of literature that demonstrates this?


texts: Effect of opposing electric charges on cells

texts:
Is the affect on a cell between two negatively charged plates theoretically similar to between a positively and negatively charged plate?  In other words, would it induce charges on the inside and outside like in the other case:

But it would induce negative charges on the left and right outer sides of the membrane and positive charges on the inner sides:


texts: I have recently realised that one of my friends had brown scars or marks inside his eyes. He says that he doesn't know what they are and has been there since young. What could this possibly be ? Are those parasites ?


texts: What is this plant with yellow large fruit?

texts: Found this in a garden in San Francisco. Can't decide if it's pomelo, capri lemon or something else, ideas?


texts: Is this modification of Livak's 2-delta delta CT method valid?

texts:
I have done a modification to include qPCR efficiency in the calculations:

In a given gene I calculate the fold changes relative to an arbitrary sample. That sample will be one and the rest will vary according to 2-dCT (equation 13 in Livaks paper). The efficiency comes into play when 2 becomes 1+efficiency (e.g. 1.9 when efficiency is 90%).
The gene of interest will be normalized by the reference gene:
$$\frac{(1+\text{efficiency})^{-\Delta CT_\text{GOI}}}{(1+\text{efficiency})^{-\Delta CT_\text{ref.}}}$$

This makes sense to me more because it includes PCR efficiency and keeps the all groups in the calculations. But I can't tell if I am missing somethng, since no one has descirbed this approach before.

What do you think?


texts: Analysing the ERP (Event-Related Potential from EEG recordings) in terms of the P-300 wave

texts:
I am trying to understand how to analyze ERP (Event-Related Potentials) from EEG recordings in focus on P-300 waves.

I have come up with a few questions which I hope you might be able to help with:

I assume that the number of repetitions af the stimulus should give better results, but I am not sure why. On one hand, it should help because avaraged results are usually better in neurosciences. On the other hand, maybe there is an unwanted adaptation effect of the subject?
So, are repetitions wanted in this kind of experiment?
There are time points in which I didn't expect P300 but the brain activity was not 0. I understand that there is always a background activity in the brain, but maybe there is more to it? And if so, are there certain frequenciess that are more likely to happen under these conditions?
When I analyze the data using an avarage response, should I assume anything on the P300 response?
What is the recommended Sample Rate I should use. I guess there should be an advantage for high sample rate for more resolution bur I am not sure about that. Am I right, or maybe a lower sample rate has advantages thst I am not aware of?


texts: Can sperm cells penetrate the cell membrane of non-ovum cells?

texts:
Sperm cells have tiny bags of enzymes on their tip (the acrosome) which allow them to penetrate the ovum. My question is whether or not the process that allows sperm cells to penetrate the cell membrane is specific to ova, or if it allows them to penetrate other types of cells.

In either case, a quick description of the process would be greatly appreciated!


texts:
I'm doing my High School biology final on Progeria, and am wondering what type of mutation causes this disease.

I know that the LMNA gene codes for the "prelamin A" protein, and that protein contains a farnesyl group that is then not able to be removed (in the case of Progeria). The abnormal form (with the farnesyl still attached) of prelamin A is then called progerin, and attaches to the nuclear rim resulting in an abnormally formed cell nucleus, making mitosis impossible.

Is this a structural mutation? What sort of mutation is this?

Thanks in advance.


texts: identification request - medium size fly invasion

texts:
I have two invasions going on!
the one here: identification request - tiny flies invasion
and this one:

We are in Berlin, Germany. This fly is 2.5mm long vs 1mm wide, and seems to like the dark and colder area of the apartment. They arrived at the same time as the tiny ones in the other link, but they don't look similar, so I don't think this is the adult form of the other kind but maybe I'm wrong.
They came with the heat, looking for shelter.


texts: How much salt [NaCl] is too much in DNA precipitation?

texts:
In DNA extractions, how much is too much salt in a CTAB extraction buffer? Protocols hover around 2.5 molar; if you go over this (e.g. 25 molar), will you saturate your solution, and precipitate the DNA too early?

Background:
  Most DNA extraction protocols approximate the following:

~Physical lysis
~Chemical (detergent) lysis
Phase separation (dreaded phenol-chloroform-isoamyl step)
Precipitate, dry

Variants are plentiful, but a common feature of steps 1\2 is inclusion of CTAB and NaCl in the extraction buffer - detergents and salts help to rupture the cell membrane, but (maybe more importantly) CTAB 'selectively'  complexes and precipitates out organic impurities (saccharides, proteins...) while DNA/RNA are left in solution.

For this to work, the net-negative charge of the DNA phosphate (PO4-) backbone needs to be neutralised allowing the DNA to stay in solution: sodium (Na+) ions are attracted to the regular (PO4-) groups, while more irregularly spaced charges*  in proteins etc. associate tightly with CTAB, and 'fall' out of solution: you keep your DNA in the liquid phase and purify, with excess salt washed out at the end using repeated 70% EtOH washes.

Would excess Na+/Cl- effectively level the 'selective' properties of CTAB? 'Salting-Out' the DNA from solution (disrupting the solvation shell) is used in step 4, most often with sodium acetate and 2-propanol: how much salt can be used in Steps 1\2 before the DNA is precipitated out with other organic materials? Are there other considerations (e.g. salts and organic solvents in Step 3)?

First description I've found for this is Zhou (1996), but a really good protocol on it is Wilson (2001).

*: presumably?


texts: Was there ever a very first Homo sapiens?

texts:
My friend keeps saying that there was a first Homo sapiens. Meaning, there was a very first human being that was ever born.

I can't really understand what she means to say from a selection/gene mutation perspective. I can't understand how there would be anything that could be considered the very first human being.

Was there ever a very first, singular human being that could be discerned as such?


texts:
What is Difference between “Archenteron” and “Gastrocoele”.
Are they same or different?
Gastrula is characterized by Archenteron or Gastrocoele or Both?


texts: Why the total phosphorylation of certain neuronal proteins decrease during development?

texts:
Looking at the effects of RIM1a which is a protein involved in neurotransmitter release. Any ideas as to why its total phosphorylation decreases as the rats develop?

Many thanks

Image; https://i.gyazo.com/16170fd79bd1f96517e028dfa2e70fbf.png

Paper; http://www.cell.com/cell/pdf/S0092-8674(03)00727-X.pdf


texts: I would like to know if every cell is competent or if there are any cells that are not competent.


texts:
This 2014 Oct 14 article by Jolene Bouchon avouches:

How do you know if your bivalves are alive? Immediately get rid of anything with broken or damaged shells. Clams and mussels shells should be slightly open, and should shut quickly when you tap on them. If they're closed, don't shut, or float in water, they're dead. Introduce them to the trash. Oyster shells, on the other hand, should be closed tightly. And, as with all fish and shellfish, your bivalves should have a fresh, oceany smell with no hint of fishiness or ammonia.

Screenshot below hails from 0:15.
Jasper White avouched the opposite on Epicurious.com

When submerging the steamers in the water, watch for any that float—this means that they're already dead and should be discarded. (Note that when preparing mussels, the opposite is true: They clamp shut tightly, trapping air in the shell, and therefore should float when alive. Discard any that sink.)

So who's correct, and why?


texts: Is high metabolism linked to high evolutionary turnover?

texts:
I recently read The Dinosaur Heresies by Robert T. Bakker, a 1986 popular science book presenting arguments for an active lifestyle and high metabolic rate in dinosaurs.

One of the arguments that Bakker presents relates to the pattern of species and genera in the fossil record over time.  He states that "warm-blooded" animals (i.e. animals with high metabolic rates) are expected to have higher turnover of taxa and faster rates of diversification.  Dinosaurs have high species and genus turnover and rapid diversification, which Bakker interprets as evidence for a high metabolism.

This argument rests on the claim that high metabolism is correlated with high evolutionary turnover.  Setting dinosaur physiology aside, I wonder how reliable the underlying assumption really is.

Is there good evidence that metabolism and evolutionary rates are causally linked, perhaps due to the ecological strategies that warm-blooded animals tend to adopt?


texts: Are there real world examples of one way isolation between two populations?

texts:
I know that for two populations A and B, there are situations in which there is a two way exchange of individuals between the populations, and there are situations in which there is no exchange of individuals between the populations.  I have thought before of a situation involving one way isolation between two populations, in which it's easy for individuals from population A to immigrate to population B, but impossible for members of population B to immigrate to population A.
I tried searching to see if I could find any examples of one way isolation between populations, and couldn't find any examples, although I don't know if this is from not using the correct keywords to find it, not knowing where to look, or there being no known examples of it.
Are there any real world examples of the one way isolation I mentioned between populations?


texts: Would the lysogenic cycle for the reproduction of viruses be considered a form of naturally occurring transformation since DNA from the virus is being incorporated into the DNA of the host cell?


texts: How to validate the use of an anti-virus monoclonal antibody in IHC by spiking a fresh organ with infected cultured cells?

texts: I have assessed the specificity of a particular monoclonal antibody against a virus by immunofluorescence. I'd like to further validate it by testing it by IHC. Therefore I'd like to infect cells in culture, and then inject them in a piece of fresh organ, fix in formalin, embed in paraffin and then cut slides before performing IHC. Is there any protocol or references to do so ?


texts: Are there known 3- or 4-nucleotide RNA linkers with no RE sites?

texts:
Question is rather self-explanatory. I'm looking for a non-cleavable RNA sequence to act as an RNA linker.

I mention 3- or 4-nucleotides only, but making such a sequence with 2 nucleotides is rather easy as seen below, but I've encountered some difficulties in transcription.

  GAGGAAGGGAAAGGGGAAAAGGGGGAAAAA...

This also works for just about any random sequence of G's and A's.


texts: Using different polysaccharides for coagulation

texts: Would a particular type of polysaccharide be better at coagulation than another? For example, would the presence of cellulose in a bio-coagulant be more effective at coagulation than the presence of starch or glycogen? I would like to know as I am doing an experiment about it and since nobody has done this before, I don't know whether having a higher concentration or ratio of a certain polysaccharide in a bio-coagulant compared to other polysaccharides will have an effect on coagulation efficiency?


texts: Are Protocadherin Gamma Cluster transcripts considered separate genes?

texts:
The PDCH@ cluster of genes share exons and are therefore isoforms of each other.  However, they are considered separate genes, by both HUGO and Ensembl.

A "gene" is defined as "a locus of co-transcribed exons" (Venter 2001), and this locus clearly fits that definition with no ambiguity. So why are these transcripts considered separate genes?


texts: Are there any companies that sell Totalseq antibodies that can bind fluorophores conjugated on another antibody?

texts:
Are does anyone know of any company which sells Totalseq antibodies that are capable of binding to fluorophores conjugated to another antibody? In this context, I plan to use the Totalseq antibody as a secondary antibody.
Thank you in advance for your kind help.


texts: New earliest life found, what are the implications?

texts:
So a couple of days ago it was announced that new fossils of microorganisms were possibly discovered around former hydrothermal vents. According to the paper these fossils "are at least 3,770 million and possibly 4,280 million years old" making them the earliest instance of life found so far. If the upper estimate is correct that would mean these organisms existed "only" ~250 million years after the formation of Earth.

Does this discovery shake up any of our previous ideas and/or provide new insights about the earliest life?


texts:
I have heard that during meiosis, homologous chromosomes from each parent "cross-over", which enables the off-spring to inherit some alleles from the mother and some alleles from the father.  The picture below illustrates this "cross-over", but of course this must occur at multiple sites, rather than just the one shown in the picture.

Now my question is what causes the chromosomes to align perfectly during cross-over so that the loci of a particular gene will substitute for the corresponding loci on the homologous chromosome, as opposed to being substituted with a completely random locus?  Does each gene have a unique non coding sequence before it specifying what gene it is to enable this process to occur?


texts: How would real-time blood glucose monitoring work?

texts:
Is it possible to perform real-time blood glucose monitoring using a wearable non-invasive device (similar to a fitness band measuring heart rate)? I'm aware that there are some devices in the market developed by medical companies but most of them require you to stick a needle in your body and it also requires you to switch needles and reapply it every few days.

How can blood glucose be measured in a non-invasive way?


texts:
I was searching for any review unravelling the structure-function motifs responsible for RNAse activity. Or at least a well-composed review of RNAse superfamilies that are described nowadays (with linkage to their functional activity). My PubMed search performed didn't give any valuable results for that.
Any specialists to comment?

Thanks in advance!


texts: Why is the chordate nerve cord described as hollow when it appears to be solid?

texts:
My textbook says arthropods have a double, ventral, solid nerve cord. And chordates have a single, dorsal, hollow nerve cord.
What is hollow exactly in a cord that looks like this?


texts: Identify this bug (which looks like a cross between a beetle and a bed bug)

texts:
I am located in a large Eastern European city. During this summer, a new kind of bug has started appearing in my house (or more specifically, coming into my house from the garden). It's about 1.5-2 cm long, doesn't appear to have any wings, and a relatively strong exoskeleton (makes an audible crack when the bug is squished). Its favorite activities seem to be either sitting in the middle of the floor, waiting for someone to step on it, or sitting on the ceiling and then falling onto somebody's head. Whenever I see one of them, it's almost completely stationary, regardless of the time of day.

Here are pictures of it (sadly, they're very grainy due to my phone's camera's low quality).


texts: The mechanism of the evolutionary rate hypothesis

texts:
There are several hypotheses for explaining the latitudinal gradients in species diversity (link). Of which, the evolutionary rate hypothesis states that warm temperature increases the rate of speciation. I want to know why warm temperature facilitates evolution.

This is not a question, but... some other hypotheses specifically discuss how a factor influences the rate of evolution (e.g., the size hypothesis discusses how large area can promote speciation). I think temperature hypothesis is a better name for the evolutionary rate hypothesis.


texts: Is there any websites that provide the DNA sequences of food samples?

texts:
We can get many DNA sequences at NCBI websites for free. Is there any websites that provide the DNA sequences of food especially meat, for free?

When I read papers regarding food authentication, they only stated the exact DNA sequence for the primers only, not the DNA sequence of their food samples. Why primers? Is it because scientists from the same field can guess what the sample's sequence will be?

Alternatively, if there's no site that shares the DNA sequence of food samples, is there any other place where I can get DNA sequence of mixed species or mutation? For free.


texts: What I know about metabolism is that,during exercise body uses carbohydrate first then fats and then protein,so my question is why does body prefer glucose first as fuel for energy and what makes glucose biochemically preferred molecule to be metabolized first


texts: Database of time lapse stem cell differentiation

texts: Currently I am working on a project about modelling the social behaviours of embryonic stem cells (or induced pluripotent stem cells). I need a series of time-lapse live cell images which recording the stem cells behaviours in cell culture, also with markers showing the differentiation state of each cell. I wonder is there public resources of this kind of data?


texts:
Humans have approximately 21000 genes but they probably make more proteins than that. This has been explained by many mechanisms like alternative RNA splicing.

My question is - If what we call as "introns" and "exons" vary so much, then how is the  number of introns present in a genome determined ?


texts: What sort of fish is the big one in this picture? I saw it in an aquarium so I don't really know anything about its habitat.


texts: Cat's tail movement as an indicative of tension

texts:
It appears to me that tail's twitching in the cats indicates how much tension the individual is under. During a hunt, when a cat tries to stay invisible, while approaching a target it is almost immovable, yet the tip of the tail keeps on moving restlessly.

Is there an explanation for such a behavior? How does it help?


texts: Most actual karyotypes online appear as single chromosomes (unreplicated). I was under the impression that a micrograph of the replicated chromosomes was taken during metaphase of mitosis and thus should show up as duplicated sister chromatids instead of single chromatids post anaphase.  Are the arms of the chromatids just so close to each other that they are hard to distinguish?


texts: Can COVID-19 affect a person a second time?

texts: I keep hearing people are recovering from COVID-19 virus. Is there any chance that same person can become infected with COVID-19 for a second time?