texts: What is the reason for 'microcytic' anaemia?

texts:
I know the causes for microcytic anaemia are Fe deficiency, prolonged inflammation, Thalessemia, Sideroblastic etc. All these logically point to a decrease in Haemoglobin synthesis - either Haeme or globin.

But my doubt is, what exactly causes the microcytosis? Lesser Hb can explain the hypochromicity, but how does it explain the decreased MCV?


texts: difference between "Petri dishes" and "Petri plates"?

texts:
In microbiology, we often hear "we use Petri dishes to prepare our cultural media".

Which is correct — "Petri dishes" or "Petri plates"?


texts: Why does magnesium deficiency is considered as a rick factor for some types of human cancer?

texts: I am not really sure how to explain this question but briefly, I just learned about the role of magnesium as an anti apoptotic agent as opposed to calcium during apoptosis. If so, shouldn't it also make it harder for the body to eliminate the malignant and cancer cells, too? How come low levels of magnesium is linked to some types of cancer?


texts: How does the brain’s limbic system work together to form a working memory, short-term memory, and long-term memory?

texts:
In the past few days, I was reading about the limbic system and how its components (hippocampus, hypothalamus, thalamus, etc.) cooperate.

Among papers and forum posts I read about how those components interact and how each of them plays a vital role in the memory formation.

But, is there someone who can give me an abstract view of how the limbic system components form the cycle that results in the formation of memory?

Something like:

The sensory signal comes through the Temporal lobe.
Goes to Thalamus where it is classified as new, existing or similar to already existing memory.( maybe somewhere between this or maybe after the next step the working and short-term memory should be involved?)
Goes to Hypothalamus to be classified as good or bad experience.
Goes to Hippocampus so it can be saved the neocortex at some point (while sleeping for example).

and so on...

Thanks!


texts: How many cells does the smallest animal have?

texts:
Note: question rewritten to prevent misunderstanding and make it more answerable

I know that some small animals like C. elegans display surprising sophistication with a very small number of cells. But I wonder, among the animals with known/estimated cell count, which has the fewest cells?

To make the question answerable, please note these constraints:

I'm only asking about members of the kingdom Animalia, so single cell organisms and colonials like Vovox are excluded. If there are single cell organisms which are classified under Animalia (I think there aren't, but not 100% sure), I still want to know about the smallest multicellular animal.
I'm only asking about species where we can distinguish individuals. If some kind of polyp or sponge is just a bunch of cells which can merge with or separate from other cells and remain a viable organism, it's not interesting.
Please only consider species where the adult form reaches some size and stops growing. (Macroscopic) examples like the tapeworm, which continues building more proglottides throughout life, or fish which continue getting larger as they age, are excluded.
If the species consists of distinctive, stable "subgroups" of different sizes, the smallest size subgroup counts. For dogs, the size of the average chihuahua counts. For C. elegans, the size of the hermaphrodite (959 cells vs 1031 in the male) counts.
What counts is the number of cells in a healthy adult of the species or the relevant subgroup. For non-eutelic animals, make that the average healthy adult. Not the smallest ever observed exemplar, and also not amputated or stunted exemplars.
I am aware that we haven't discovered all microscopic animals yet, and haven't counted the cells of all discovered ones. Still, I'd like info on the current level of knowledge, including current known cell count, evidence that something has less than the current lowest known-for-sure count, and other relevant information.


texts:
Supposing we have the genotypes “Aa”, “AA”, and “aa”... which are not mono-allelic (not imprinted and not X-inactivated). Does the dominance of the “A” allele over “a” allele affect which gene is transcribed, or are both alleles transcribed and the allelic dominance only determines the observed phenotype?
I’m guessing it’s the latter, but that makes me confused as to what the concept of allelic dominance would mean for mono-allelic expression, where only one allele is always expressed and observed.


texts: To have TBE vaccine during allergic times with mild asthmatic symptoms?

texts:
My assistant says that if you have asthmatic symptoms you cannot have TBE (Tick Born Encephalitis) vaccine, although you are living in the active zone of TBE.

Cases

mild allergic symptoms
allergic symptoms under control of Montelukast (asthma in control)
asthmatic symptoms (bronchitis, rhinosinutis, repeated cough)

What are the risks of having this vaccine during allergic symptoms when you have mild asthma medication (Montelukast)?

I still think the risk of encephalitis is higher if you get TBE from nature than from vaccine.
Are there really some cases where encephalitis is caused by the TBE vaccine?


texts: Why can't intermediate filaments be used as tracks by motor proteins?

texts:
A motor protein like kinesin-1 cannot use an IF as a track because it lacks polarity.

Can someone elaborate on this answer?


texts: What determines the duration of larval stage?

texts: Why do insects have very long pre reproductive periods and very short reproductive periods? Is there a common characteristic that can indicate the duration of these stages or offer an explanation for the same?


texts: Finding targets of transcription factors

texts:
I'm trying to find an easy way to get a list of putative targets of a particular transcription factor (for example, STAT1). I'm interested in targets determined using both experimental and computational evidence. I thought it should be easy to obtain such a list, but I'm having a hard time. Could anyone help me with this, preferably with specific, step-by-step instructions. As a bonus, I'm also interested in the reverse problem, which is, for a given gene, obtain a list of all transcription factors for which there is evidence that it regulates that gene.

Thanks,

Jennifer


texts: Presence of reaction module in bacteria but not in Eukaryotas (human)

texts: From the statistics page, I found that the Module-M00008 is present only in bacteria and not Eukaryotes. Why so? I noticed that all the compounds necessary or the reaction are present in human body and also all the enzymes required for the reactions are present in human body too. Then why does that reaction not happen in humans?


texts: Can Covid-19 (similarly to HIV) infect T-Cells?

texts:
I'm interested in better understanding this Nature publication, discussing the potential for Covid to infect t-cells.

After describing the results they conclude:

"Based on the results of pseudovirus and live virus infection, here we proved that (1) SARS-CoV-2 could infect T cells, (2) SARS-CoV-2 infected T cells through receptor-dependent, S protein-mediated membrane fusion, and (3) infection could be inhibited by EK1 peptide."

Is this big news? I am not an expert but I believe that HIV's special trait is it's ability to infect CD4+ T cells. If this virus has this ability, does it mean it will have long-term effects like lymphocytopenia, which occurs in HIV?


texts:
Is it true that in an enzyme-catalyzed reaction, the rate of reaction does not vary with varying osmotic pressure?

Instead of just a true or false answer, why does it, or why does it not vary with osmotic pressure?


texts: Is trembling an advantageous response during periods of anxiety?

texts:
I originally had planned to ask about whether there was any biological truth in the popular phrase "shivering with fright".  However, after doing a fair bit of googling it seems that there is a lot more medical reference to trembling as a result of anxiety (1) (though I would imagine the distinction to be fairly minor).

I was, after about an hour of fruitless searching, beginning to wonder if it was a phenomenon created only in literature (such as being 'frozen by fright') rather than genuine human physiology, however then a website described how many people often have minor trembling before exams, interviews or other high pressure situations - something I can attest to myself!

This hasn't really changed the biological purpose behind the question however - is there any advantage to shivering in a fight or flight situation or is it more a side effect of the release of adrenaline or another chemical response? I am struggling because I can only imagine it being a real disadvantage (consider for example an organism hiding from a predator - uncontrolled movement in a stressed situation can not be beneficial) so the only way that I can see is that the shivering must be linked to something that is a definite advantage in a high stress situation.  What would that be?


texts: Can neurons divide if somehow centrioles are introduced in nerve cells?

texts:
I am a biology student, so i know that centrioles are required for cell division, and i also know that nerve cells lack centrioles.

My question is that if somehow compatible  centrioles were introduced to the nerve cells, would their division be possible?


texts: Effect of nerve pills and relationship to Shingles

texts: Do nerve pills actually suppress the nervous system and how would that effect the Shingles virus which is known to activate under large amounts of stress?


texts: Can you approximate Cardiac Output by Ohm's law?

texts:
I found this sentence from my notes which I cannot understand

PR < CO, CO $\uparrow$, PR > CO $\downarrow$

where

\item CO = AP / PR, Cardiac Output = Arterial P / Peripheral Resistance

I cannot understand the first sentence.
I cannot understand how you can deduce by Ohm's law the relationship.

What is the point of the first sentence?


texts: Examples of references for mathematical approaches in bioinformatics that are applicable to linguistics?

texts:
Do you have any classic references for mathematical approaches in bioinformatics that are applicable to linguistics (or vice versa)?

EDIT
I am mainly interested in approaches to reconstruct the history of languages, the rate of language mutation, phylogenies of languages, etc.


texts: Can human brain memory be removed by EMP?

texts: The human brain is the most complicated human organ so it is hard to examine it completely but based on what we know do you think (or do you know from some source) if a human memory can be removed by emp(electromagnetic pulse) ? (If so do you think it would be pernament or temporary?)


texts: How do you find pre-miRNAs from mature miRNA Blast output?

texts: So in short, I did a blastn with standalone blast using all known miRNAs against the EST sequences in a genome (word length 7 and e-value 0.01). Now to confirm one of the next steps would be obtain the pre-miRNA sequence of each hit and do an mFOLD for structural confirmation. Each paper I read always mentions to get a sliding window (of 70 - 100 nt length) but how do you get this sliding window from the BLASTN output.. Do you have to code something yourself or is there an easier way to do it. Thanks.


texts:
I have questions regarding "selection using insertional inactivation".

In a typical DNA recombination experiment using plasmid pBR322 where a new gene in inserted in the place of tet gene, it is said that entities with the recombinant plasmid can be selected by growing all the bacteria in two different medium: one with tetracycline and one with ampicillin.

I know that pBR322 contains two genes that make it resistant to both tetracycline and ampicillin, and also that the newly created plasmid will only be resistant to ampicillin, since its tet gene is no longer functional.

So in the plate with tetracycline, only entities with the original plasmid will grow. In the plate with ampicillin, however, entities with the original plasmid and the modified plasmid will grow.

How can this be a selection when two different types of entities are growing in one plate?

Am I misunderstanding the meaning of "selection" in this case?

My explanation above seems very immature, so it would be great if someone can provide me with deeper understanding.


texts: When is it best to use Hoechst vs. DAPI for nuclear staining? They seem to be very similar on paper. Are there situations where one is clearly preferable?


texts: The concepts of relatedness - Hamilton's rule and kin selection

texts:
Here is a quotation from this wikipedia page

  The relatedness parameter (r) in Hamilton's rule was introduced in
  1922 by Sewall Wright as a coefficient of relationship that gives the
  probability that at a random locus, the alleles there will be
  identical by descent.[14] Subsequent authors, including Hamilton,
  sometimes reformulate this with a regression, which, unlike
  probabilities, can be negative.

Here is my question:

What are all the different definitions of relatedness in biology?

how do we calculate them?
what do they mean?


texts: I have a pretty simple question which always kept me intriguing since childhood and I couldn't find its precise answer yet. Why do we cough by cold water. Recently I had flu and found very strange correlation between cold water and coughing. Even seconds after drinking cold[er] water, I started coughing as you all would have experienced as well. So why does it happen?


texts: Does E. coli survive at any pH level? If I was to incubate it in agar of different pH, would it still form a bacterial lawn as it's called?


texts: What's behind the amazing colour combinations in pests & insects?

texts: What's behind the amazing colour combinations in pests & insects ? Do this colour combination signals any character/ poison of the pest/insect ?


texts: Historical recovery from mass extinction events

texts: Is there a way to generally characterize how species "regrew" after the various mass extinction events happening periodically from 450 Ma to 65 Ma.  Would the surviving species just start back where they had left off and evolve willy-nilly as if the destroyed 50% or 70% of biodiverse species had never existed?  Or would the biome in some way have the capacity to regrow something resembling the former order based just on the remaining species.  This is probably a whopper of a dumb question, my apologies in advance.


texts: Could a fetus properly develop in micro/zero-gravity?

texts:
I suppose another way of looking at the question is: how important is gravity for the development of mammal fetuses?

And if things would go wrong, what sort of things would they be, and what would be the result?


texts: Why difference in degree of folding in a cell?

texts:
For a cell to maintain constant volume, input should be equal to output of substances.

My question is, if the basolateral membrane, by less folding can attain the same rate of transport as of the apical surface with microvilli, then why do cells produce more foldings (microvilli)?

Why is there a difference in degree of foldings on each side?


texts: I'm trying to detect the level transcriptional protein inside cells. However, the cells contained both of this protein that is phosphorylated and not phosphorylated. Can RT-PCR detected the level of both of them? If yes can it detect them separately?


texts: Are there any medical treatments which no longer work because humans have evolved?

texts:
(Not sure if this should be on the medicine SE)
There've been plenty of medicines that no longer work because the target pathogen has evolved resistance, e.g. penicillin is no longer an effective antibiotic. Have there been any treatments that no longer work because the human body evolved?
I imagine since evolution is a slow process, if there is such a medicine, it would've been around since antiquity (to give evolution the most time possible to work).


texts: Can nerves in the human body be spliced with a form of electric wire?

texts:
This may be a ridiculous question, and is hypothetical, but I'd like a well-supported answer.

Is it possible to splice copper wire (for example) into the human nervous system? Would the charge carried along the nerves then travel into the wire?

Say for example that I wanted my reflexes to be improved (because I know electrical current travels significantly faster through copper wire than our nerves), and wanted to replace a section of my nerves with copper wire. Would it work?


texts: Do biologists use the word "solubilize" to mean "dissolve"?

texts:
I work with biologists who often use the word "solubilize" to mean "dissolve".
Is this correct usage? I keep correcting them (I'm not a biologist, but I help with writing), and we've argued about it. Not all are native English speakers, so I've been attributing it to that. But maybe they're right. I want to know.
The context here is pharmacology - taking drugs in powder form and dissolving them in a vehicle for dosing lab animals.
I thought "solubilize" means to make something more soluble by adding (for example) soap. (for example: https://www.thefreedictionary.com/solubilisation ).
But they use "solubilize" to mean "dissolve". That usage doesn't seem to be standard English, but maybe it's normal usage as a term of art in pharmacology.
Is it?
For scientific writing in pharmacology, what is the standard usage? When we mean (standard English) "dissolve", which word should we be using, in order to be clearly understood and conform with standard professional terminology?

Added: Some of the commenters seem to misunderstand what I'm trying to ask, so I'll try to clarify.
I can read dictionaries as well as you can, and Google is my friend, too; I'm not asking what the standard dictionary definitions are (I already know).
I'm asking about how working biologists, English-speakers, use these words.
Do practicing biologists/pharmacologists use these terms differently than the standard English definitions? Are these "terms of art" in those fields, with a different definition? Or not?
Some of my colleagues insist that, in their field of biology/pharmacology, the word "solubilize" is used to mean what the dictionary says "dissolve" means. Are they correct, or are they mistaken (presumably because they're not native English speakers)?
I'm not a biologist and so don't know from personal experience. The people I work with are biologists but not native English speakers, so I'm not convinced they know either.
Thus, I'm asking here.

I've been asked for a sample sentence re how it's used. I don't see how that affects the answer, but here:
"Diphtheria toxin (List Biological Laboratories, Cat #150) was solubilized in sterile water at 2 mg/mL, aliquoted, and frozen at -20 C."
Is this correct usage or would "dissolved in sterile water" be better?


texts: Flight trajectory of domestic pigeons on sudden noise

texts:
In places where people feed pigeons, its a common sight to see them fly off suddenly when there is a sudden disturbance.

When they do, there is an interesting pattern that these birds follow.

Say there is a huge noise in the surrounding, all the pigeons fly off together, and return to the very same place, traversing a semicircular path of some fixed radius. The flight of each bird relative to another is also interesting, looks like some sort of a wave. It seems more like a formality rather than of some utility (since they return to the same place).

I assume this has been studied and has some significance. Does it happen in other birds too? What is this phenomenon called?


texts:
What sorts of EM frequencies are emitted by the human body?
Are there any processes in the human body that produce Radio/Microwaves or uv/x-rays/gamma rays?


texts: How do the brain and nerves create electrical pulses?

texts:
The information between the brain and peripheral nerves is sent via electrical pulses or signals, How then does a non-metallic human cell manage to conduct an electrical
signal?


texts: Confirmation of organoid's character with the respective organ

texts: How can we verify that the Organoid formed from culturing stem cells shows the exact characteristics of the organ it is developed for?


texts: what is the difference between pituitary dwarfism and thyroid dwarfism?

texts: My book (Comprehensive Biology class XI, by J P Sharma ) mentions of two kinds of dwarfism- "Pituitary Dwarfism" and "Thyroid Dwarfism" but does not provide any details about the matter. so please help me.


texts:
At 06:43 in The Secrets of Nature video Sky Hunters, The World of the Dragonfly - The Secrets of Nature the narrator says:

Scientists have been collecting dragonflies since the eighteenth century, but there’s always been a difficulty. Dragonflies quickly become deathly pale, they lose all their color. That’s why collectors have usually preferred to concentrate on butterflies...

and an image of rows and rows of uncolored dragonflies pinned to a display are show.
Question: Why do dragonflies lose all of their coloration once they die?
 click screen shots for full size


texts:
The first polar body formed after meiosis-I is completed in oocyte, may or may not divide.

Why is the statement that "it may or may not divide"? Is it random ?


texts: Effect of light intensity on the frequency of stomata

texts:
According to this article, the frequency of stomata increases with an increase in the intensity of light. What I inferred from this is, since the rate of photosynthesis increases at higher light intensities, more C02 is is required and hence the frequency of stomatal openings increases.

I know that the Light Harvesting Complexes inside chloroplasts use light to release electrons, which are then subsequently used in photophosphorylation. If we compare the process with the photoelectric effect, we shouldn't see an effect of the intensity of light, but instead we should see changes for different frequencies(which we already do).

So how does the rate of photosynthesis increase with higher light intensities?
Is the mechanism of light absorbtion by LHCs similar to that of a photoelectric cell?


texts: How many times is a single strand of mRNA translated into a protein?

texts:
In other words, is the mRNA damaged or somehow "marked completed" in the translation process? Or does it pop out the other side of a ribosome ready to be translated again? If the latter, how many copies of a protein result from a single strand of mRNA?
Thank you in advance!


texts: What species of worm is this? Found in underwear on Ecuador coast

texts:
My wife found this worm in her underwear this morning when she woke up.  It wasnt attached to her or anything. About 4-5 inches long. Redish in color and slightly see through, meaning you could sort of see its organs.

We are in Puerto Lopez Ecuador.


texts: What is the actual process and reflexes that cause the goose bumps? Why is it an evolutionary advantage to have goose bumps in the first place?


texts: Is the coronavirus getting less dangerous?

texts:
Please note

This question is based on data from the UK government's web site (data from the ONS). I am not taking this data as accurate, but am using this as it is the only source of data I can find, and is what (presumably) the government themselves use when deciding what to do. My question is about trends, not the accuracy of the government's data.

I'm also not asking about the wisdom of government policy, that is a political issue, and I'm only interested in biology and statistics here.

Finally, I realise that my analysis is all quite rough and ready, as there are many indeterminate factors involved. Again, I'm interested in an overall picture, so a rough analysis is probably reasonably informative.

Here in the UK, the data on new virus cases seems to imply we have a serious problem...

This was plotted using data from the government's web site, and shows that the number of new cases has risen dramatically since the beginning of September. I used a 5-day average to smooth the line (same for the other graphs below)
However, if you look at the number of deaths, it seems that the increase is nothing like as rapid...

Whilst there has been an increase since the beginning of September, it is very much more modest, and not necessarily indicative of a serious problem.
Now, I'm not a medical expert in any way, but it seems to me that the fact that the number of deaths is growing more so much more slowly than the number of new cases indicates that things may be not actually be getting worse, but may be getting better. Sure, more people are getting the virus, but the percentage of those who are dying (which I would have thought is the most important issue we need to consider) is not increasing.
To check this, I divided the number of deaths by the number of new cases, and it showed a very different picture...

As you can see, there isn't a noticeable increase since the beginning of September. To examine this more closely, you can zoom in on the past 8 weeks or so...

Whilst there was a jump in the middle of Sept, it hasn't really increased since then, and may even be decreasing.
So, is my analysis wrong, or is the virus actually becoming less of a problem in the UK?


texts: Are human teeth only diphyodont or both diphyodont and monodont?

texts:
Many books say human teeth are only diphyodont .But premolars appear only once and one molar appears later which should be considered monophyodont.
 Dental Formulae :

CHILD -
 1. Incissor -2/2
 2. Canine -1/1
 3. Premolar-0/0
 4. Molar-2/2
ADULT-
 1. Incissor-2/2
2.Canine-1/1
3.Premolar-2/2
4.Molar 3/3 .

Here the 3rd molar and two premolar appear only once. Therefore human teeth should be both diphyodont and monophyodont


texts: Is ability to easily pollinate desirable?

texts: In Mendel's crosses was it desirable for the plants to be able to cross-pollinate and self pollinate easily ?


texts:
Perhaps it would not be wrong to say that "translation/transcription goes in the direction of 3' to 5'" or "in the direction of 5' to 3'";that's because these statements are ambiguous, not specifying "XX's".
However, I am confused.
So I would like to clarify by clarifying the "XX's".
My Question;

Are the following understanding correct?

(1) Transcription;
In the case of transcription, the RNA polymerase moves in the 3'→5' direction of the template strand of genome DNA, and the ribonucleotide attaches to the 3' side of the mRNA during synthesis, am I right?
(2) Translation;
In the case of translation, the ribosome moves (relatively) in the 5'→3' direction of the mRNA, and the amino acids are attached to the C-terminal side of the polypeptide, am I right?
(3) Overall;
The genetic code is "the sequence of the complementary strand of genomic DNA read in the 5'→3' direction, with T replaced by U". For example, if the sequence of the complementary strand of the genomic DNA is "5'-ATGTTT...termination codon-3'", the corresponding sequence of the mRNA is "5'-AUGUUU...termination codon-3'", which is "N-terminal - methionine - phenylalanine ...C-terminal" sequence.


texts: Is it possible to buy a DNA sample with a specific mutation?

texts:
I would like to test a genotyping method (ARMS) on a specific human snp (heterozygous or homozygous ).
Unfortunally, we do not have any dna samples with the mutation.
Is it possible to buy somewhere a dna sample with the mutation ?
Otherwise, can you redirect me to other solution like directed mutagenesis?

Thanks


texts: How does mannitol decrease intracranial pressure?

texts: What is the mechanism by which mannitol is able to reduce intracranial pressure? Also why aren't other substances used for this purpose such as say sorbitol (an epimer) or in fact any other hyperosmotic agent?


texts: Is this a bed bug? Found this on the pillow as I was putting my daughter to sleep

texts:
My husband found this small (~4mm long) insect on a pillow while putting my daughter to sleep in our New Jersey (USA) suburb home.
We checked our daughter's and our own mattress as well as the rug, but we found no mark or other bugs. No one has recorded any bites.
We had bedbugs years ago in another home in another city, but have not seen evidence previously in this home. We moved in about 2 months ago at the end of September. We have not travelled recently due to Covid.
We are petrified and will call someone first thing in the morning but need to know


texts: Acquiring Covid-19 vaccination through kissing with viral vector vaccinated person

texts:
The mechanism of COVID-19 viral vector based vaccines (AstraZeneca - Vaxzevria, Johnsen, Sputnik V - Gam-COVID-Vac, Johnson & Johnson - Janssen, etc. ) is delivering the genetic information of the corona virus through adenoviruses.
Would it therefore be possible to get "infected" by droplets (f.e kissing) with the manipulated adenovirus from a viral vector vaccinated person and consequently acquire the same vaccination?


texts: Father with mutated mtDNA- why isn't his offspring at risk?

texts:
Mothers transmit their mitochondria (and therefore mtDNA) to their offspring and fathers don't. Lets assume that father had a mutation of the gene that encodes mtDNA, would then be his offspring at risk? Why?

I also found the following statement:
"The current genetic advice is that fathers with mtDNA mutations are at no risk of transmitting the defect to their offspring."

How can that be true? Is it because of gene silencing?

Thank you in advance!


texts: How many Watson-Crick + Hoogsteen triple base pair combinations are there?

texts: Are these triple base pairs the only Watson-Crick + Hoogsteen triple base pairs possible? Furthermore, are TAA and TAT mixed up? This image is from Wikipedia, so it's possible that it's erroneous.


texts: To which negatively charged components of the cell envelopes do the crystal violet complexes bind in gram staining?

texts: The gram positive have negative components in the peptidoglycan layer in the form of teichoic acid phosphodiester bonds, and the gram negative have negative components in their outer membrane in the form of lipopolysaccharide. Is that where the crystal violet binds?


texts:
Why aren't green eyes more prevalent, given that the green allele is dominant over the blue one?

My understanding is that human eye colour is determined by two genes:

1) HERC2, with alleles Bx, BB or xx,
2) gey, with alleles GG, Gb or bb,

where

B means brown
x means not brown (this is less confusing than using b for blue here, because having no B allele in HERC2 doesn't necessarily give someone blue eyes; their eyes will be either blue or green depending on the gey gene)
G means green
b means blue.

Capital letters stand for alleles that are dominant; lower case, ones that are recessive.

So the 'algorithm' goes:

1) look at HERC2; if it's anything other than xx, you've got BROWN eyes
2) if HERC2 is xx, look at gey; if it's anything other than bb, you've got GREEN eyes
3) still here? then you've got BLUE eyes

My question is this: why is it that green eyes are so rare if the green allele is dominant over the blue one? When a blue-eyed person and a green-eyed person interbreed, their offspring will either be equally likely to have green eyes as blue (if the green-eyed parent is Gb) or always have green (if that parent is GG).

But many more people have blue eyes than green eyes, despite blue being recessive to green.

The obvious answer is that people with blue eyes (xx bb) and people with green eyes (other xx-ers) have tended to avoid breeding with each other to a large extent. Is any other explanation in the ring? Perhaps the greens are catching up?


texts: On stochastic Lotka-Volterra predator-prey model

texts:
I am currently working (as a mathematician) on some estimations involving an stochastic predator-prey type model in which some of the coefficients have been perturbed by a Brownian Motion yielding to a system of stochastic differential equations.

The basic formulation of this problem can be found for instance in this article.

We have the following model

\begin{equation}\label{0}
    \begin{cases}
    dX(t)=X(t)\left(a-bX(t)-\frac{sY(t)}{\beta+Y(t)}\right)dt\\
    X(0)=x>0,\\
    dY(t)=Y(t)\left(\frac{h X(t)}{\beta+Y(t)}-c-fY(t)\right)dt\\
    Y(0)=y>0.
\end{cases}
\end{equation}

where we use Holling II response function.

In the literature (mostly mathematics literature) the authors propose to perturb the birth rate of the preys $a\mapsto a+\dot{B}_1(t)$ and the mortality rate of predators $c\mapsto c+\dot{B}_2(t)$.

This yields to the following (stochastic) system

\begin{equation}\label{1}
    \begin{cases}
    dX(t)=X(t)\left(a-bX(t)-\frac{sY(t)}{\beta+Y(t)}\right)dt+\sigma_1 X(t)dB_1(t),\\
    X(0)=x>0,\\
    dY(t)=Y(t)\left(\frac{h X(t)}{\beta+Y(t)}-c-fY(t)\right)dt+\sigma_2 Y(t)dB_2(t),\\
    Y(0)=y>0
\end{cases}
\end{equation}

I know nothing about biology but I am concerned about a couple of things regarding this particular formulation:

If we assume that the Brownian motions are perturbing the birth/mortality rates, how can I interpret the fact that this new "perturbed" rates can become negative (due to the effect of the BM). Does it have any sense (in the framework of this particular model) to talk about "negative birth rate" or "negative mortality rate"?
What if the "perturbed" mortality rate goes beyond $100 \%$? Mathematically nothing "wrong" will happen, but what about the interpretation?

Notice that the "noise"  and the model as a whole can be interpreted differently (ignoring the fact that we are actually modelling the dynamics of two species) but my main issue is that if I(together with many authors) am stating that we perturb a certain parameter I believe that we must respect the basic assumptions of the model!

I hope everything's clear and I thank you all in advance, any opinion or suggestion will be welcome!


texts: Are There Exceptions to Animal Cells not Having Cell Walls?

texts:
In the January Issue of SciAm (discussing Haemophilia):

  When damage occurs to blood vessels, exposure of the blood to collagen in the cell walls and material released by the cells triggers the activation of clotting factors.

I read the original in print, but it is available online here.

This seems to imply that animal cells (in this example, those of humans) have cell walls.  I sometimes see similar implications in other resources.  However, in elementary biology, one is taught that animal cells never have cell walls.

Therefore, my question: Are references to animal cell cell walls (such as the above, for human animal cells) simple mistakes--or are they exceptions to a generalization?


texts: How can haired mammals synthesize vitamin D?

texts: The human body can synthesize vitamin D in the skin from cholesterol, when sun exposure is adequate. But how can haired mammals do it? Do not they need it?


texts: What is the benefit of fever during infections?

texts: When people get sick, they often develop a fever. What is the effect of an increased body temperature on viruses and bacteria in the body? Is it beneficial to the infected body? Importantly, often fever-reducing agents like aspirin are prescribed when people are sick. Doesn't this counteract any benefits of fever?


texts: Bug identification: Striped grub/worm, 5mm long, indoor highrise 9th floor, Ottawa, Canada

texts:
I've seen two worms like the one below tonight, but none before.  A neighbour with a dog moved in next door 2 days ago, and it is close to our wall that I've seen them.  However, she hasn't seen the bug.  I saw one on the kitchen tile floor and one on the kitchen counter.  I'm in Ottawa, Canada, in a 9th floor apartment of a highrise.  I have no pets.
Not sure if it's relevant, but it also got very cold in the last 2 days (negative teens in terms of celsius) -- never seen these grubs in previous years when it got this cold.  It's mid-December.  The grub is about 5mm long.


texts:
Today I was watching a show on Discovery Science (Everything You Need to Know About). In that show they were talking about toxins and venom.
In that they mentioned Dioxin and its effect. And suddenly I heard the unexpected, that Dioxin damages Pancreas!!
Dioxin spreads due to contamination by food & mainly beef (as mentioned in the show).
It is produced mainly because of (chlorinated) burning of fossil fuel, coal,trees,PVC, plastic.
As there is a spike in the diabetes in recent years. And there was a increase in pollution from last few decades.

It looks like Dioxin is culprit which is lurking behind to attack people and causing Diabetes.

Am I thinking right?


texts: This paper uses Pied Flycatcher as a study species. For the population of Pied Flycatchers they studied, 'pedigree information' was available. What exactly does this 'pedigree information' mean?


texts: number of RNA pol II molecules in a given human nucleus?

texts: Does anybody have any estimate on the number of RNA pol II molecules in the nucleus of a given human cell? For example, how many RNA polymerase type II protein complexes would there be on average at a given time in, say, a human immortalized lymphoblastoid cell line (LCL)?


texts:
From Learning from the Octopus 1 (p. 201):

  A complimentary line of defense would be to lower the chance of infection by lowering the prevalence and virulence of diseases…just keep the variability of nature intact…West Nile virus increases its prevalence when bird diversity declines.

and on p. 212:

  A high diversity of bird species has recently been shown to be a key factor in reducing transmission of some diseases such as avian flu.

Why is this so?

What does bird diversity have to do with reduced disease transmission?


texts: WHO Essential Medicines vs Essential Medicines for Children

texts:
Per the WHO (World Health Organization), there are a list of "Essential Medicines" such as those listed on their Wikipedia page.

Is there a database link for this directly other than Wikipedia?
What is the difference between the "Children" list and the regular list. Is one a complete superset of the other? I noticed the "Children's" list is much larger.

I would like to make an open JSON database of some sort regarding a more easily accessible and organized way of accessing this data in a Postgres database or something. What do you know like this that exists?

https://en.wikipedia.org/wiki/WHO_Model_List_of_Essential_Medicines
https://en.wikipedia.org/wiki/WHO_Model_List_of_Essential_Medicines_for_Children


texts: Do corresponding areas in the two hemispheres arise from the same stem cells?

texts:
After having asked this question about the connectivity between clonal cortical neurons, I'd like to know:

  Do corresponding areas in the two hemispheres arise mainly from the same stem
  cells, such that these areas connect to each other more strongly than to others?


texts: What is the cause of the spots on this leaf?

texts:
On a hiking trip to the Alps I found trees whose leaves showed those spots you see on the picture. I am curious about what the cause is.

Higher resolution pictures of front and back side.


texts: Why add hydrogens in molecular dynamics simulations?

texts:
In my molecular dynamics lecture, our prof said, that we always have to add hydrogen atoms to titratable groups, before we start the force field simulations, and that it is especially important for Histidine.
But why is that? Why do we always have to add the hydrogen atoms? And do we only have to do that for titratable groups, or for all?


texts:
Hailed as the "gold standard" of sequencing, I was wondering to what Sanger sequencing owes its incredible accuracy to. If possible, I would like a quantification of the accuracy (because I doubt it is 100%, though possibly very close).

I understand ddNTP chain termination and the strategies involved in Sanger sequencing but I lack the connection to accuracy.

Thanks!


texts: Is the occurrence of a particular enzyme in a given subcellular location a random phenomenon?

texts: Enzymes occur in different subcellular locations. Some are specific to a given subcellular location, whereas others are heterogeneously distributed. What evolutionary decisions influence the occurence of enzymes in particular compartments?. Are the locations species-specific?


texts: Central of Dogma? reverse transcriptase says No

texts: I know what a reverse transcriptase is but I'm not sure why it is suggesting that the central dogma may be wrong -- RNA first then DNA instead of the well-known sequence of DNA -> RNA -> protein


texts: How do researchers map root systems of plants?

texts:
For example, here is a picture of the root systems for some prairie grasses:

(Click image for higher-resolution PDF) from: http://www.conservationresearchinstitute.org/educational-offerings.html

How is it possible to follow one root thread 15 feet down? Especially when they are so densely packed in the top foot of soil that you couldn't dig at all without destroying roots.


texts: How does salt concentration affect chromatin compaction?

texts:
I've read that the primary obstacle to the compaction of chromatin is the negative charge on the DNA phosphate-sugar backbone. This negative charge is slightly stabilized by the positive charges on histone proteins. In solutions with high salt concentrations, chromatin adopts a more condensed state, whereas in solutions of low salt concentration, chromatin is less condensed. The explanation I found was that cations from the salt help provide additional stabilization to the negative charges on the DNA molecules—thus, solutions with higher cation concentration promote greater condensation of chromatin.

But what about the anions in the solution? A solution must be electrically neutral; when salt concentration increases, the concentrations of both cations and anions increase. Even if the salt cations stabilize the DNA's negative charge, won't this be perfectly offset by electrostatic repulsions between the DNA and the salt anions?


texts: Are receptors integral membrane proteins or peripheral membrane proteins?

texts: Integral membranes proteins serve as transporters. Peripheral proteins serve as cell adhesion molecules, antigens and enzymes. So what about receptors? Which proteins carry out the duty of receptors?


texts:
I am thinking this question.
Thrombosis can result in

organisation of thrombus,
sepsis
thromboembolism,
fibrinoid swelling
adiposity.

I fibrinoid swelling (edema) (4) can occur.
Also, I think (3) thromboembolism can occur and also (1) organisation of thrombus.

What can thrombosis result in?


texts: How do parrots stabilize their field of view without moving their necks while walking?

texts:
Based on my search online, I have found some theories which try to validate the activity of some birds (like pigeons) which involves moving their heads and neck while walking. These theories include - Assistance with balance, Providing depth perception, Sharpening their vision. Also, most of the studies state that similar to our eye movement, they need to move their heads along with their eyes to stabilize their surroundings visually.
If the above mentioned hypothesis is true, then how do some birds which do not move their heads while walking, manage to visually stabilize their surroundings and balance themselves?


texts: Agony, Hydrophobia and viruses in the light of evolutionary principles

texts:
I'm undergraduate physics student, but I've always been interested in biology. So I have a couple of questions about an application of the evolutionary principles to practice.

Agony as the last stage of dying.
Hydrophobia as symptom during Rabies.

Now I'm going to clarify what exactly I do not understand. In the first case it's not clear for me how this mechanism helps to survive, how it can help at all? In the second case it's not obvious why this virus causes such a symptom. As I think virus always create favorable environment for himselve (for reproduction). But how could water prevent it?


texts: What are the characteristics of a promising drug?

texts:
The drug development industry is a multi-billion dollar economy powered by a multitude of research bodies from industry and academia. A big risk is that drug development costs are in the tens of millions of dollars when looking at the most successful drugs

Generally speaking, what makes a good drug for research for those researchers working on these projects? Why are some potential drug pursued and others not? What traits, according to the experts, justifies such a vast investment?


texts: Could alpha-numeric taxonomy of fungi make things simpler?

texts:
Please feel free to construe this question broadly--I don't see why the question would not apply to branches of biology other than mycology.

If the goal of taxonomy is to create classification of fungi that reflect evolutionary relationships, and if this results in a more or less unmanageable proliferation of names, might it not be a good idea to use a numeric or alpha-numeric system instead of a verbal one? One author estimates there may be as many as 5 million species of fungi (and it may take 1000 years to catalog them). If we did manage to note them all would the result really be useable? The ease of storage and retrieval alone would seem to commend a numerical approach.

I assume someone has thought of this before and I guess viral taxonomy does this to some extent. Are there any proposals like this afoot?

Thanks for any insights.


texts: If a woman was fertilized with her own DNA, would it be her clone?

texts:
Several questions:

1) Can human DNA fertilize an egg, without having been naturally packaged in a sperm cell?
2) If a female had her ovum fertilized with her own DNA, would the fetus be her clone?
3) If this technology of fertilizing ovum from arbitrary samples of human DNA were effective, would males be unnecessary for reproduction of the human species? (No political implications, just a thought experiment.)

Thank you for your insight!


texts: Is it possible to combine live attenuated and non-live vaccines?

texts: There are many combination vaccines available but I've noticed that there don't seem to be any with both live and non-live components, e.g. DTaP/IPV/MMR. Such combinations could be useful in some cases, since most developed countries give a second dose of MMR (or MMRV) at the same time as DTaP/IPV. Is there a biological reason that this is difficult?


texts: Effect of doubling volumes of PCR reagents

texts:
We ran PCR with a positive control and two lanes of sample. We used the same sample, but in one PCR mixture we used a total volume of 50μL (25μL Taq, 5μL forward&reverse primer each, 10μL sample, 5μL dH2O) while in the other we halved each volume to a total of 25μL. Pipetting was done by the same person.

The positive control and the 25μL total volume lane gave nice and clear bands, but the 50μL sample showed nothing. How could this be explained?

Edit: We only ran one PCR with all the samples simultaneously, so no second thermocycler or different temperatures or anything. Didn't even consider that option!

Edit 2: In case it's relevant, we were using this: http://www.chemheritage.org/discover/collections/collection-items/scientific-instruments/perkin-elmer-cetus-model-480-dna-thermal-cycler.aspx


texts:
Are there any lectures available on Patch-Clamping?
Were can I find a mathematical model of Patch-Clamp? (that can be easily implemented in matlab).
I have found some step-by-step protocols on (Springer book site) but nothing to useful--I am setting up a new rig. Where can I find protocols that have worked and have been tested?


texts: How do cells age and die if they are dividing into new cells?

texts:
If cells in our body keep on dividing into new cells how do they ever grow old?

The only cells to grow old would be defunct cells or those who won't divide into new cells like nerve cells.

What am I missing here?


texts: Does increasing the speed of a reaction (say by introducing a catalyst) shift the equilibrium of the reaction? I assume it does not, as Gibbs free energy is not changed, but I am not sure.


texts:
Twins could be monzygotic i.e. identical twins and dizygotic i.e. non-identical twins.Well, monozygotic twins occur when a single egg is fertilized to form a zygote which later divide into separate embryos.

Now, My question is Why does the embryo collapse splitting the progenitor cell into half?
While searching for the answer I found certain theories (possibly without evidence). Following are those theories;

An enzyme in the sperm causes them to split.

I have known only a few hyaluronidase and hydrolysing enzymes present in the sperm acrosome which helps penetrating the ovum by lysis of Zona pellucida.

A mutation in the mother's RNA which may control embryogenesis in the first nine days.
The splitting of embryo is more of a random process then genetically governed one.
Genetic mutation which leads to rejection of one group of cells by the other.


texts: Evidences supporting that coronavirus (SARS-CoV-2) came from bats

texts: I was trying to find evidence that the coronavirus (SARS-CoV-2) came from bats. So far I know that coronavirus shared 96.2% overall genome sequence identity with a bat coronavirus RaTG13 from horseshoe bats who identified as natural hosts for SARS-related coronaviruses which were the direct progenitors for the origin of SARS-CoV and also comparing the receptor-binding domain (RBD) of 2019-nCoV to SARS-CoV, the structure of the RBD allowed for the use of ACE2 (angiotensin-converting enzyme 2) as an entry receptor. I wanted to know that apart from these two pieces of evidence are there any major evidence that also suggests that indeed SARS-CoV-2 came from bats.


texts: This is a picture of a tree in Nepal. Can somebody identify it?


texts: Advanced books about molecular biology and genetics

texts: I'm finishing my third year of biochemistry and doing gene therapy practicals during the summer. I'd like to buy a book that describes flow of genetic information (transcription, translation, replication, splicing...) and its mechanisms in depth (such as transcription factors, regulation, etc). The closest thing I currently own is Lehninger's Principles of Biochemistry, but most of it deals with metabolism. I've also got to know about Molecular Biology of the Gene, but I'm not sure if it's what I'm looking for. I'm not interested in books about heredity or population genetics.


texts: I'm pretty sure it's a beetle due to the lines on it's back/rear but I'm not positive and if I'm wrong I need to take action quickly. Thanks in advance :)


texts: Where do the bacteria within the vagina originate from?

texts: I understand that it's feasible the bacteria within the gastrointestinal tract originate from the food we eat and air we breath, but where does this population of microbes originate from?


texts: Hamming distance between two DNA strings

texts:
By definition from Wikipedia, the Hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different. In other words, it is the number of substitutions required to transform one string into another. Given two strings of equal length, compute the Hamming distance.

So to find the how many differences there are between two strings, say we have two DNA strings A and B:

A = TGACCCGTTATGCTCGAGTTCGGTCAGAGCGTCATTGCGAGTAGTCGTTTGCTTTCTCAAACTCC
B = GAGCGATTAAGCGTGACAGCCCCAGGGAACCCACAAAACGTGATCGCAGTCCATCCGATCATACA

Throw them to two arrays A and B. Therefore, If

(= count 0)
(cond
   [(symbol=? A[1] B[1]) /do nothing just move on to the next pair of string]
   [else (add1 count)] ;; counter:= counter + 1;

output would be the counter.

Is this the right logic flow to go with this problem? Any suggestion to write this on python or Scheme?


texts: Could a strong magnet field repel the body before damaging it?

texts:
Could a magnetic field be strong enough to damage the body or erase the brain?

Blood is slightly diamagnetic, so if the field was strong enough, could it repel a body evenly?

Could a diamagnetic material go through electrolysis with water then ingested to give the body more diamagnetic properties?


texts:
My background is not genetics. 2.I am not interested in knowing how dna sequencing or genotyping is done. 3. I am interested just in the nature of the results as described here.

Now coming to the question: Humans have two sets of chromosome in each cell. So if I say sequencing chromosome1, what does that actually mean? Which of the two chromosome's gets sequenced? Of genotyping-do comparison take place between two+two=four chromosome1's? Or is my entire undertanding flawed?


texts: Is it safe to publish a person's genome?

texts:
I recently went through the process of having my genome analyzed by 23andme, and received my raw data.

Its very interesting to me, and I want to share it with the world.

Is it safe to publish the raw genome to a public site, or are there reasons I should keep this information private?

What could someone do with the raw genome of another person? Outside of privacy concerns, is there any potential for malicious concerns from someone with this information?


texts: Is there any artificial species (in particular, an artificial species of animal)?

texts:
Dogs were artificially selected from wolves, but a dog and a wolf can produce fertile offspring, and thus are of the same species. I had heard that the aurochs and cattle were different species, but I could not find this information anywhere. I had heard also that some artificially selected flies are considered to be a new species.

Is there any human-made species (especially a species of animal) which is not able to produce fertile offspring witch any other species, in particular with the one from which it evolved?

EDIT: (A similar question in different words.) Is there any human-made animal lineage which was conceived by artificial selection and which is broadly accepted as not being a race or subspecies, but a species on its own.


texts: Validity of comparing gene expression levels between alive and <24h postmortem cohort

texts:
There is a recent paper about assessment of a suicidal risk in psychotic patients https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4759104/

One of the important points is that the authors compare gene expression levels between alive patients and post-mortem suicidal completers (RNA extracted from blood <24h post-mortem).

In result, they identify suicide-specific blood biomarkers that also have "biological roles in immune and inflammatory response, growth factor regulation, mTOR signaling, stress, and overall the switch between cell survival and proliferation vs apoptosis".

Do you think that one may really perform this type analysis if we know that post-mortem biochemistry is very different? Plus they killed themselves via different means (gunshot, hanging, electrocution, slit wrist etc.)


texts: Can encoding of miRNAs in introns not cause dysregulation of gene expression?

texts:
For example, consider a gene X which has an intron which encodes a miRNA that downregulates expression of another gene Y.

When the gene X is translated, this miRNA will appear as a byproduct of splicing, then expression of gene X will inhibit expression of gene Y, which could be deleterious.

How did the mechanisms of gene expression evolve to avoid possible unplanned interference in gene expression?


texts: When a stoma’s guard cells try to swell and open the stomata, they actively pump out protons outside of the cell. This causes a membrane potential, where the inside of the cell is negative with respect to the outside. This then causes potassium ions, which are positive, to rush into the cell, mitigating that potential. However, my texts say that anions such as chloride and malate ions follow potassium into the cell as well; their rationale is that positive ions must be balanced by the presence of negative ions. I do not understand why this is the case. If you extruded positive ions (protons) out of the cell and allowed positive ions (potassium) back in, there would be no ionic imbalance to draw the anions from where they’re idling. Could someone clear this up for me?


texts: Are there any viruses that have infected all humans in the past or present?

texts: Are there any known viruses that have managed to infect all of humankind either in the past or presently, either benign or otherwise?


texts:
Do they act directly on the muscle and actually relax muscle tissue and ease spasms, or do they just prevent your brain from receiving signals that inform you of tight muscles?

In the latter case, it seems like your brain would sort of become "immune" to the pain even though the muscle is still in a spasm.

I'm obviously not a biologist, just curious about this.

How do muscle relaxants work?


texts: Hodgkin-Huxley Model and Propagation of Action Potential

texts:
I'm studying Hodgkin-Huxley model of action potential, and I have some confusion.
In the well-stated HH model, we have time constants for each ion currents, described as the reciprocal of the sum of forward rate and backward rate.
In the caple theory, there is another time constant that is defined as the multiple of cell resistance and cell capacitance.
Is there any relationship between the two time constants? Do we have to think the two processes, which means the 'generation' of action potential and the 'propagation' of it separately?
Thanks.


texts: Evolution of the energy generating system in mitochondria

texts:
Both yeast and humans have mitochondria. Given that yeast have a much shorter time between generation I would expect evolution to have had more time to optimize mitochondria of yeast.

The main function of mitochondria in yeast is essentially similar to that in human cells.

Is their efficiency roughly the same or did the stronger evolutionary pressure allow yeast to evolve much better mitochondria? Is there empirical research about mitochondria that studies the difference between the mitochondria of different species that includes metrics of their efficiency?


texts:
I have an inquiry regarding the exact function of height genes.

To my knowledge, although they are heavily regulated by epigenetic factors, height genes can have either an "on" or an "off" allele, and the probability of the person being "tall" shows positive correlation with the number of "on" height genes alleles he has.

However, I could not find any resources showing the exact function or mechanism of these genes' function. Do these genes code for a specific protein when they are "on"? And if there are any, how do these proteins increase the probability of the person being "tall"?

Thank you.


texts: Why is the character of bleed/blood in normal menstrual cycle different from mid cycle bleed(Spotting/breakthrough bleeding)


texts: Why would diffusion be faster across a non-specialised tissue?

texts:
The standard protocol for a person experiencing chest pains is to chew a 300mg aspirin tablet, the argument being that chewing rather than swallowing the tablet results in the aspirin entering the blood stream faster.

From a biological standpoint, why is this the case?  Given that the stomach and GI tract are specialised tissues to allow for maximum diffusion, why would it be faster to pass aspirin across the gums (bucaal administration?) tongue and cheeks which are not specialised for this purpose?

It is not just a special case for aspirin either, as HypostopTM/GlucogelTM (acute treatment for hypoglycaemic shock, essentially concentrated sugar) is applied directly to the gums or cheek with a similar argument that in critical situations it is faster.

The only suggestion I could find was  very vague from the "Merck Manual":

  The stomach has a relatively large epithelial surface, but its thick mucous layer and short transit time limit absorption
  Which I assume could mean that it is the reduced absorption rate in the stomach that makes the oral membranes faster, yet it also says that the delay in the stomach is brief.

I'd be really interested to know the biology behind this!


texts: Can dolphins actually communicate linguistically?

texts:
Humans use "language." By language, I mean the thing I am using right now to talk to you.

I know dolphins and orcas have very complex communication systems and also seem to process linguistic and gestural commands.

But do they have their own languages? Where is the evidence for or against? If we take two group of dolphins Group A and Group B, would Group A speak one language and Group B speak another?


texts: Is erythropoietin released when breaking down RBCs

texts:
I came across the MCQ in my physiology book, it says:

Erythropoietin.....
i) may decrease the life span of RBCs.
ii) is not released on breakdown of RBCs.
iii) may stimulate the stem cells.
iv) is formed mainly in liver.
v) is lipid in nature

I think ii) and iii) are correct answers, as when breaking down RBCs we don't get erythropoietin, and erythropoeitin stimulated stem cells to produce RBCs, am I right?
Because the book says that only one choice is correct. Help me please! Is there something I don't understand?


texts: Are longer and shorter DNA similarly charged?

texts:
A longer DNA molecule would have more phosphate groups, so it should have a greater negative charge, right? It was taught in my class that only terminal ends of DNA are charged and all the phosphates in the middle are not charged.

My teacher said that this is the reason that Electrophoresis separates the fragments. All DNA have same charge and so same force on all of them. Then difference in masses would give different acceleration and thus separation of fragments according to size. But isn’t Gel Electrophoresis more like a sieve where longer molecules move slowly and shorter pass through easily?


texts:
What is the relationship between term "Gene isoform" and "Protein isoform"?

Say a gene can make 3 isoforms, will it produce only (maximum) 3 isoform protein?


texts:
I've heard that stomach lining has the fastest reproducing cells and the brain has the slowest.

Where in the human body does mitosis occur and at what rates do these cell reproduce? Is there a chart for the whole body available?


texts: Can a ribozyme be present on two different RNA molecules?

texts:
Suppose we have a ribozyme that consists of an 'enzyme' strand and a 'substrate' strand. (e.g. hammerhead ribozyme)

Is it possible to have the enzyme strand of the ribozyme on one RNA molecule and the substrate strand on another RNA molecule (such that it allows multiple-turnover reaction)?


texts: How did this spider evolve to mimic exactly a human face and arms?

texts:
So I came across something terribly amazing today, that is, a video showing this species of peacock-spider, that literally, transforms into a human face waving his arms about.

What could have possibly given rise to this?

I can understand the arms waving around, but why the uncanny human-face template, complete with eyes, nose, mouth, etc.

I do not believe this to be a case of anthropomorphism on my part, (seeing what I am familiar with), because I cannot imagine any other natural case where such symmetry in a pattern would closely resemble a human face.

Would appreciate any explanation. Thanks!


texts: Is this some sort of book lice or bed bug? Online shipping box

texts:
I found a few of these in the box when I opened it after delivery. Worried it could be a bed bug nymph. There were a few in the edges of the box. I’ve been opening up boxes in the garage so haven’t bought the items inside yet but still concerned.
Pics attached. Would appreciate any help in identification.
Color is mostly clear white.


texts:
I found this bug last year in August in Bharatpur, Rajasthan, India. The scale at the bottom of the picture is in mm and the size of the bug seem to be about 1.5 cm.
It looks a bit like Halyomorpha halys, but all the pictures of H. halys I've seen show white markings and sometimes more colour and not the dark markings as shown here.


texts: How much mass does a person lose in a day through breathing and perspiration?

texts:
Water and carbon are lost through perspiration and breathing.

How much mass is lost in this way in a single day for a typical person?


texts: Is the sun's damage to skin sufficient to warrant protection anytime the average person goes outside or just for extended periods?

texts:
According to the American Academy of Dermatology website,

Everyone needs sunscreen
Sunscreen should be used every day if you will be outside. The sun emits harmful ultraviolet (UV) rays year round.
Even on cloudy days, up to 80% of the sun’s harmful UV rays can penetrate your skin.

I also saw this video a while ago.

The two of these make it sound like we should be wearing sunscreen even if I step outside to get my mail.

Is the sun's damage to skin sufficient to warrant protection anytime I go outside or just for extended periods? What is the general criteria this kind of organization uses to determine what is "sufficiently" damaging to warrant sunscreen protection?


texts: Can photosyntetic cells be genetically modified to grow at a faster rate?

texts: I hope the question is not silly, but I wonder if a sort of genetically modified plant "cancer" could be used for carbon sequestration. For example, cancer cells like HeLa have been reproduced in tons, and as far as I know their growth rate is very high.


texts: What's this black, white and orange beetle?

texts:
Found in Toronto Canada.
Maybe 1-2 mm long but I'm not a good judge of measurements.
Should I be concerned it has friends? I've dealt with carpet beetle larvae in several homes over 7 years and an praying this isn't an adult.


texts:
I know that in botany there is a wide classification for plants that can survive in hot deserts (semi-arid or arid) and harsh climates such as 4-season countries with a tendency to droughts each year (such as Palestine).
This classification, as I understand it, is thermophilic plants (hot loving).

But there is also the classification thermophilic plants which are also halophilic (salt loving), i.e. can survive and even flourish in extremely low and salty ground? Examples of such plants are found in the Ein Feshkha reserve near the Dead Sea in Israel and other similar Thypa and other plants reserves near the Dead Sea (current) shorelines in Israel, Palestine and Jordan.

Is there term for thermophilic-halophilic plants and if so, what is it?


texts: Is Phenylalanine hydroxylase gene biallelic?

texts:
Since the PAH gene is biallelic, and there are many disease causing mutations, most PKU patients are compound heterozygotes.
  (paper)

  Compound heterozygosity in medical genetics is the condition of having two heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state.
  (wikipedia)

  More than 400 disease-causing mutations have been found in the PAH gene. (wikipedia)

Why is Phenylalanine hydroxylase gene considered biallelic when PKU is also caused by the presence of two different mutant reccesive alleles at a locus with more that 400 types of mutations occurring in nature?


texts: What do bones need to grow outside the body?

texts:
In what environment outside of a living organism can bones grow?

If I were to put an arbitrary human bone in a room and attach a bunch of tubes to it, or dunk it in some kind of solution, where would I have to connect the tubes and what stuff would have to be in the tubes/solution to make the bone grow as if it were inside a living organism?


texts:
How can I know if I can combine anti Cenp-C and anti Rod1 antibodies? I want to use them to label those protein and analysing cells by fluorescence microscopy.

*Cenp-C is kinetochore protein and Rod1 is localized on the kinetochores or spindle microtubules during cell division.

Can I just combine them if they are from different animals? how can I know they will not have cross reactivity?

Thanks


texts:
OK, this may be a stupid question…but here goes.

Does the human eye “white balance” itself?

I assume that each human perceives colour slightly differently according to the peculiarities of their own eye, but within parameters (notwithstanding colour-blindness).

But does our eye (or brain) white balance? Or do we simply all see our own personal colour balance?

If the eye can white balance in real life, can it also colour balance a photograph that has been taken at the wrong colour temperature.

So, say I shoot and print an image shot at 2000K. The image printed will have its luminance information intact, but colour-wise, it will be very, very orange.

If I could somehow exclude all other vision from my eye and fill my entire viewing capacity with that single image, would my eye balance the colour back to a true white?

If it does not, why not? What goes on in our brain to say “this is an image at a fixed colour temperature, so you will see it as an orange hue”

Please excuse me if this is an eye-roller of a question. I’m not a Biologist, so I am well aware I may be demonstrating my own ignorance in asking the question!


texts: What concentration of table salt is needed to kill bacteria in sweaty gym clothes?

texts:
My gym clothes retain an unpleasant musk even after washing them with warm water and detergent. I've experimented with soaking my gym clothes in salty water before washing them. My hypothesis is that the high salt concentration will cause plasmolysis in the cells of the bacteria. It has worked with mixed results; I'm never sure how much salt I should add or how long to soak the clothes.

I've looked for answers but I can only find papers with highly technical results.

(1) Can the odor-causing bacteria be killed with a salt treatment?

(2) If so, what concentration of table salt is needed?

(3) How long does the treatment need to last for plasmolysis to occur?


texts: How come Draq5 stains cytoplasm and membranes under confocal

texts:
Just an imaging question on the back of my head.
For nuclear counter stain, Draq5 has been an excellent choice for many people over many years. And I too love it.
The working principle of Draq5 is the nuclear dye Draq5 binds to doubles strand DNA, especially d-A and d-T. That is to say it is very specific to stain nucleus DNA, minimal binding to mitochondria DNA, and no binding to RNA. It is also a very good live cell permeant dye.
In practice, we use it to stain cell nucleus and then perform image analysis, the primary objective in image analysis is identification of the cell object, usually through nucleus staining. No problem, Draq5 does this perfectly, I can see my image crispy clear.
Next, it comes to the estimation of the entire cell, that is to find cell membrane boundaries. A huge advantage of Draq 5 is it also stain cytoplasm and cell membrane weakly, allowing the accurate detection of cell boundaries. Comparing this to Hoechst dye, which also stain nucleus and weakly cytoplasm only for estimation of cell boundaries. This is unlikely a Draq5 non-specific binding, since data from resistant cancer cells that have membrane drug pumps still retain Draq5 very well.
I'm not a chemist so that one thing in the back of my head is:
Why does Draq5 bind cytoplasm and outlines cell membranes that well? Given it is highly specific to bind A/T in double strand DNA grooves. Presumably the dye is binding to its cytoplasm target and membrane target via different mechanisms. Can someone explain that?


texts: Origin of melatonin: oxidative stress defense OR circadian rhythm?

texts:
Question

Which functional role of melatonin came first?

Regulation of the circadian rhythm
Defense against oxidative stress
Other

Background

I was well aware of the important role melatonin plays in Human sleep behavior, and circadian rhythm regulation, quoting the Wiki page:

  Melatonin, also known as N-acetyl-5-methoxy tryptamine,1 is a
  hormone that is produced by the pineal gland in animals and regulates
  sleep and wakefulness.2

What I was not so aware of, but now quite fascinated to learn about, is melatonin's role in oxidative stress management. In fact, the quote below is taken from the sentence immediately following the one above, in the same Wiki page:

  it functions as a first line of defense against oxidative stress.3

Related Stack Bio Discussion

I also came across this Stack Biology answer to the question "Does melatonin change the appearance of humans?", quoting it:

  Melatonin works as an antioxidant and helps in removing free radicals
  from the body ... I would have to conclude that
  melatonin could have a part to play in maintaining the beauty of your
  skin.


texts: How does adjuvant enhance the immunogenicity of antigen?

texts:
My question is, How does adjuvant enhance immunogenicity of antigen?

I just want to know deeply about it , Any suggestions will be helpful!


texts:
I have computer science background and I am trying to understand the equation below.

The average value of the G + C content of a protein-coding region is
given by :

(G+C)=  $\sum_{\alpha} (I_\alpha *f _\alpha$ )/3

$I_\alpha$ = Maximum number of nucleotides C and G that appear in one of the
synonomous codons for given amino acid

$f_\alpha$ = Frequency of amino acid α.

Where does the 3 in the denominator come from ?


texts: Differentiating Antaresia (Children's Complex) Pythons using something other than color pattern

texts:
I have a standard wild-type Children's python (Antaresia childreni) that I'm planning on breeding in the next few years and was just sold a male "Children's python" that I think might actually be a spotted python (Antaresia maculosa). Unfortunately, he's of some kind of reduced pattern morph (granite, I think) that has completely blown out his natural patterning, so my main method of identification is useless.

I know that along with the Stimson's python (Antaresia stimsoni) all of these snakes have been identified as "Children's pythons" at some point in the not-too-distant past, but someone saw fit to distinguish between them and I can't seem to find any basis for doing so that isn't based on range and pattern, both of which are meaningless for a captive-bred snake of a morph that makes its natural pattern indiscernible.

Is there some reliable way to tell the difference between these snakes other than coloration and range? Perhaps some difference in number or placement of certain scales or details about the eyes?

I've included a picture in case anyone can comment and tell me what this little guy actually is on the basis of the modified pattern - but I'd still like a better way if anyone can provide a real answer.


texts: Is the poison from Stink Bugs dangerous?

texts:
I just went to kill what I thought was a moth on the wall, and instead it fell on the floor and it sounded like dropping a coffee bean (because of the hard shell)

I live in the UK and have never seen one of these things before, I thought maybe it was a variant of a woodlouse, so I just crushed it in some kitchen roll I had over my hand and saw a little stain on the paper, but I assumed it was just blood.

When I looked on the internet and discovered what it was, I smelled my hand and it stank (I'd literally washed my hands like a minute or two before killing this thing). Since I've touched my laptop keyboard and stuff, is that a problem? If I use my laptop and now eat something will it poison me or leave an awful taste in my mouth?

P.S. If this seems OTT I do have slight OCD when it comes to hygiene and bugs.


texts:
Question. Why are we (humans) more likely to help people genetically related to us than people who are not?

My understanding of this question as follows:

Because the reproduction of people genetically related to us can help us spread our genes. People genetically related to us are also more likely to help ourselves to reproduce.

Is this correct? What am I missing?

I was wondering if anybody had anything, especially intuition or some finer nuances, to add to what I have to say.


texts: In the film "The Perfect Human Diet" at 32:36, a scientist points to animal remains and states "we've got a scutella of reindeer there."  What is scutella in this context?


texts: How can a sequence be downloaded from UCSC genome browser

texts: If I have genome coordinates is there a simple way to download the entire intervening sequence from the UCSC genome browser? I found some fancy way of using ftp but I can't figure it out.


texts:
Scratching and biting helps furred animals dispose parasite insects from their surface. Is it a productive action for humans who have less fur, have hands that can pinch off parasites and can help each other out?

If evolution were perfect, humans would never scratch, and to resort to pinching off any actual parasites - scratching and biting could break skin and expose it to germs.


texts: How to combine data points from different western blots into one graph?

texts:
I am doing Western blot data analysis and I have data from two different western blots. In my two Western blots, I have labelled for the same proteins. I am comparing knockout (KO) samples against wild-type (WT) samples in my Western blots. I am making graphs showing the fold change of the level of my protein of interest in my KO samples relative to my WT samples.
The way I am doing this is to first get the normalised integrated density of my protein bands. I am studying the inactive form of a phosphoprotein. To get the normalised integrated density, I am dividing the integrated density of the inactive protein band by the integrated density of the total protein band.
I have 2 WT/KO pairs in my first blot, and I am analysing the fold change within each pair. In my second blot, I have a technical replicate of these 2 pairs.
I am dividing the normalised integrated density of the WT band in each pair by itself so that the value is 1. Then, for each pair, I am dividing the normalised integrated density of the KO band by the normalised integrated density of the WT band. These values are compared against the baseline of 1 to get the fold change.
I want to put the technical replicates from the second blot on the same graph with the data points from the first blot, so that I can compare them. However, I would like to know when outlining your protein bands in order to calculate their integrated density, do they have to be the same area amongst the 2 blots?
For example in my first blot, the outlines for the inactive protein bands all have the same area. In my second blot, the outlines for the inactive protein band are all the same area but the area is different compared to the first blot.
Similarly, for my total protein bands, in the first blot the areas for the band outlines are all the same but they are different from the band areas in the second blot.
If I want to combine my data points from both blots into one graph, do the band areas for my inactive protein & total protein have to be the same in both blots in order for the analysis to be valid? Or is this not necessary?
Any insights are appreciated.


texts: Why not self pollination for finding the genotype instead of test cross?

texts:
Test cross can tell us what's the genotype of a plant is. But we can know that even by self pollinating the plant. For example,
If a garden pea plant has the genotype TT, then self pollinating them will give all tall plants.
If the plant has the genotype Tt, then self pollinating them will give both tall and dwarf plants in 3:1 ratio.
So we can simply say that by self pollination if all the plants are of same type then the parent plant is homozygous. If the plants are in ratio them the parent plant is heterozygous.


texts: If two different diseases have more than one common pathway, the relationship between their occurences?

texts:
I just wonder that are there any special relationship between the pathway and disease occurrence.

For example, there are cancer A and cancer B (and they have more than one common pathway). Then if one person was diagnosed with cancer A, does he have a high probability for getting cancer B? Could you recommend any researches for that?


texts:
This morning, I walked out front of my house to find a medium-sized snake balled up on my driveway beneath my motorcycle. I spotted it from my porch so I didn't walk any closer. I believe it was a Texas rat snake.

I've seen a few snakes in my area but none really up close, so I watched it curiously for a few minutes. It seemed to be acting oddly - its head was tightly bent sideways at its "neck," and it was slowly coiling and writhing while opening and closing its mouth. It didn't seem very alert.

Then, a friendly neighborhood cat began batting at the snake's head, and while the snake was not acting aggressively, it did haphazardly snap back in self-defense a couple of times.

I (subjectively) assumed that the snake was injured or otherwise "done for," so I ended up moving it into the street with a long pole and crushing its head with a large rock. I had taken its lack of objection to agitation with the pole as another sign of distress.

I really don't like killing other creatures. In retrospect, maybe I could have handled the situation differently, maybe by capturing the snake and releasing it somewhere else. At the time, for whatever reason it seemed like it was suffering and I felt like I was doing it a favor, as well as potentially saving some local pets from injury.

Moral questions aside, does it sound like this snake was in fact behaving abnormally? Are the actions I described typical of a distressed snake (at least of this species), are there other plausible explanations, or is it unclear? I can elaborate if there are any specific questions.


texts: Determination of genes to be modified in epigenetics

texts:
It seems that during reproduction particular genes are targeted for modification (mutation, deletion, insertion, etc.) given environmental inputs of either or both of the parents.

If a creature was fit given its environment, its seems there is little mutation. However, if the creature becomes less fit (i.e, due to increasingly becoming prey to a predator) it will undergo increased rate of mutation to find a successful adaption to the new environment. But it seems that the mutation is also targeted to particular genes that maybe most beneficial to mutate (i.e, to develop camouflage).

This begs the question - given environmental inputs, is there something that controls gene modification during reproduction? More specifically, is there a process that targets a specific gene or trait?


texts: What kind of bug/insect is this? photo attached

texts:
This morning (a few hours after sunrise) I saw this insect running over the blanket.
I'm thinking what it is, if it's a bed bug that missed feeding time and is out of schedule (as i thought that they come out just before sunrise). And I thought they were brown, too but upon research found that they could (colorwise) look similar to this one too. Also, I have not found another one of these and my wife and I both don't find any bite marks on our bodies.  Our matress is packed in a plastic hull to not allow bed bugs to start living in it. What might this be?
Thanks!


texts: How is incomplete dominance different from codominance?

texts:
Ok let me start with the definitions of incomplete dominance and codominance.

incomplete dominance - The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele.

codominance - The situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways.

It is the standard textbook example of incomplete dominance to show a cross of red and white Snapdragons of pure bread. Which yields the phenotypic ratio of 1 red : 2 pink : 1 white. The standard text example of codominance is AB blood type where the A glycoprotein and B glycoprotein together produce a distinguishable phenotype apart from AA or BB.

I really don't understand the distinction between intermediate phenotypes and distinguished phenotypes. How is pink not distinguished from white and red. Consider a hypothetical example of some insect that interprets red, white and pink as distinguishable signals where perhaps red is a safe flower, white is ignored, and pink is dangerous. Say these signal recognitions have evolved based on the insects contrast against the flower pigment and the probability of being eaten by a predator because of increased exposure while getting nectar from the flower. I suppose I have a misunderstanding but wouldn't the red, white, and pink phenotypes be distinguishable rather than intermediates in that case?

So I'm probably just being an idiot but how is incomplete dominance different from codominance?


texts:
I read somewhere that eating a lot of salt will raise blood pressure, which will in turn damage brain tissue. This is because water molecules gather around salt ions, thus making it harder for the body to remove the excess water from the blood.

Is this true? How much salt is actually dangerous?


texts: Is the crispr (where the parts of Virus DNA is saved) section of the DNA existing in human cells aswell or is it just in bacteria cells?


texts: T-Cell Motility: does motility require direction specific actin polymerization?

texts: T-cells have been shown to migrate inside concentration gradients - both in the direction of the source or away. Even under shallow gradients, t-cells move. I argue that, to be able to move in a directed manner, a cell must be able to have a differential response of actin polymerization and philipodia. But I find it hard to believe that it is a differential response unless the sensor resolution not only communicates centrally, but is also extremely sensitive. How does this work?


texts: What kind of detergent should I use in cell culture laboratory for cleaning purposes?

texts: I work on establish a cell culture laboratory in the company where I work. All equipment are new and I want to clean lab before I start to work with cells. Is there any special detergent for cleaning cell culture lab?


texts: What is the difference between Founder effect and Bottleneck effect?

texts:
Both are examples of genetic drift in which there is a change in the allele frequency when the population size becomes small.
What is the difference between the two?


texts: Valence electrons in DNA nucleotide addition

texts: Can anyone explain the movement of valence electrons during the nucleophilic attack that occurs during DNA synthesis? The 3' oxygen starts with two lone pairs of electrons but what happens during the formation of the phosphodiester bond?


texts:
A recent report from UNOS states:

  The kidney discard rate has returned to pre-KAS levels, dropping from 20.2 percent in the first six months to 18.4 percent in months 7-10.

To me, this seems quite high considering the number of people waiting for a kidney. Why is this rate not lower?


texts: Where to find the corrected BLOSUM matrices?

texts:
I was looking at this paper which talks about the miscalculations in the BLOSUM matrices and how the "wrong" BLOSUM62 matrix performs better than the corrected version. I was trying to find the corrected version they talk about to experiment with, but the link they list in the paper appears dead.

Does anyone know where I can find the corrected matrix that the authors talk about?  (preferably a version listing frequencies rather than scores)


texts: How does smoking, an environmental factor, cause cancer, fundamentally a genetic disease?

texts: If cancer is fundamentally a genetic disease, how might an environmental factor such as smoking cause cancer?


texts: How do Mockingbirds find each other during mating season?

texts: Since mockingbirds imitate songs of other birds, how do they find each other during mating season? How can they tell it's a mockingbird singing, instead of other birds? Is there something in their imitations that still identifies them as a Mockingbird?


texts: This bugger is pecking on the side of my house. I don’t know anything about birds, but it doesn’t look like your typical woodpecker.


texts:
I am currently working on a project where I need to trim the adapters off of some single end read RNA-Seq data, and I want to know which sequences to cleave.  Illumina TruSeq adapters were used.  I have tried following Tuft's explanation and make sense of Illumina's video, but I am left with several unresolved questions.

The TruSeq Universal adapter, seems to be what binds to the flow cell and is

AATGATACGGCGACCACCGAGATCTACACTCTTTCCCTACACGACGCTCTTCCGATCT

The TruSeq Adapter Index N is

 GATCGGAAGAGCACACGTCTGAACTCCAGTCAC-NNNNNN-ATCTCGTATGCCGTCTTCTGCTTG

My impression of how the cDNA fragment attached to the adapters is :

(flow cell)
||
||
||                                             (Index Adapter)                                               (Universal Adapter)
||    3'                                                                5'                          3'                                                        5'
||    GTTCGTCTTCTGCCGTATGCTCTA-NNNNNN-CACTGACCTCAAGTCTGCACACGAGAAGGCTAGA                           TCTAGCCTTCTCGCAGCACATCCCTTTCTCACATCTAGAGCCACCAGCGGCATAGTAA
||                                                         ||||||||||||||                           ||||||||||||||                                                              <----- Must get denatured!
||        5'   AATGATCGGCGACCACCGAGATCTACACTCTTTCCCTACACGACGCTCTTCCGATCT--(5' MY DNA FRAGMENT 3')--AGATCGGAAGAGCACACGTCTGAACTCCAGTCAC‐NNNNNN‐ATCTCGTATGCCGTCTTCTGCTTG
||-------------TTACTAGCCGCTGGTGGCT                                     3'                           5'                                                                3'
||
||             ^(Flow cell oligo)              ^(Universal Adapter)                                            ^(Index Adapter)
||
||                                     TGTGAGAAAGGGATGTGCTGCGAGAAGGCTAGA                           TCTAGCCTTCTCGTGTGCAGACTTGAGGTCAGTGTG
||
||                                             ^(Read 1 Primer)                                                ^(Read 2 Primer)
||
||
||                                                                                TAGAGCATACGGCAGAAGACGAAC----------||
||
||                                                                                ^(Flow cell oligo)
||

Here are my questions :

Is this image correct in the single stranded case?
Do I have the correct primer binding site (used for the actual sequencing)?
Do I have the correct oligo for paired end reads, i.e. TAGAGCATACGGCAGAAGACGAAC---------?
Do I have the correct primer (and it's site) for the index read?

 Per Illumina, I guess I need to include this :
"Oligonucleotide sequences © 2007-2013 Illumina, Inc. All rights reserved. Derivative
works created by Illumina customers are authorized for use with Illumina instruments
and products only. All other uses are strictly prohibited."


texts: Why is it difficult to bend the waist while keeping the knees straight?

texts:
It's easy to keep your legs straight when you're standing up or laying flat on your back, but as soon as you try to sit up or bend down, you need to bend your knees as well as your waist.  (Try it.  Lay down flat on the floor, then try to sit up straight while keeping the backs of your knees pressed against the ground.  You'll have trouble long before you reach 90 degrees.)

Why is this?


texts: Why proprioceptive fibres (of CN V) have their cell bodies in mesencephalic trigeminal nucleus?

texts:
It's seen that GSA (General Somatic Afferent) fibres (of CN V) have their cell bodies in trigeminal ganglion. But the proprioceptive fibres' peripheral processes terminate at mesencephalic trigeminal nucleus, making it the only nucleus in CNS where cell bodies of 1st order neurons are present.
Why this is so?


texts: The distance the electromagnetic field of the heart can be detected

texts: A very smart friend of mine seems to get taken in by junk science. He started telling me last night that the electromagnetic field of the heart can be detected beyond 30 feet. What is the actual distance? Thank you.


texts: why secondary/booster vaccine shots may sometimes induce worse side effects?

texts:
Background:
I had my first shot about 1.5 months ago, I just had my shot yesterday. Unmistakable fever like symptom started within 4 hours. within 10 hours the whole body started aching, accompanied with chill, tiredness and headache.
2 details in this chain of event I can't explain: (this is not asking 2 questions, as I believe those 2 details are related, I just couldn't connect the dots)
1
Fever should be a function of the innate immune system, which is programmed to recognize a fixed set of signature molecules, first vaccine shot and the second vaccine shot should have induced the same innate immune response. I do have my own guess on this one: a while after 1st shot, there are now some killer T cells roaming in my blood. Once seeing "infected" cells, those killer Ts started killing and raising alarms in mass, inducing lots of macrophages into the region, as if there is a deep wound or a serious infection at my arm, thus the whole-body fevers. (Similarly, leftover production of the newly minted antibodies would start marking the "infected" cells, attracting macrophages).
2
muscle and joint pain should be due to white blood cells releasing cytokine. The vaccine's lipid particles are injected into my arm muscle, not major blood vessels. Those lipid particles couldn't travel far into my whole body, they should only merge with or "infect" mostly local cells around the injection site. local pain, local ache makes sense, why did the whole body's immune cells ALL decide to release cytokine? shouldn't the aching be a gradient though out the body? starting from the site of injection, it should hurt the most, gradually the pain will be lowered the further away from the site of injection.
P.S.
the whole question is based on the knowledge that adaptive immune response takes days to take effect.  I just assumed the 2nd shot's side effect which takes merely hours to manifest couldn't be the adaptive immune response. However, I am thinking now, maybe the side effect is the continuation of the adaptive immune response from the first shot?
PS2 NEW INFORMATION
apparently nanolipids don't just stay locally
body ache is immensely way more complicated


texts: Is there a reason for the lack of full RTK structures?

texts:
Bocharov et al. (2013) write that

  As there are no structures of full-length RTKs [receptor tyrosine kinases], we do not fully understand how different domains function together to mediate signal transduction inside the cell.

True to the above quote, I've so far only found isolated domains of some RTKs in the PDB, but no complete structures (neither X-ray nor NMR). I am a chemist by training, so am hardly an expert in this area, but it does seem counterintuitive given the general importance of RTKs in cell signalling. Is there a fundamental reason for the lack of RTK structures?

In contrast, there are examples of full-length GPCRs, e.g. rhodopsin (Palczewski et al. 2000). As tsttst brought up in the comments, this seems to be an issue with RTKs being single-pass membrane proteins, whereas GPCRs are multi-pass. How does this affect the ability to obtain a structure?

Bocharov EV, Lesovoy DM, Goncharuk SA, Goncharuk MV, Hristova K, Arseniev AS. 2013. Structure of FGFR3 transmembrane domain dimer: implications for signaling and human pathologies. Structure 21(11):2087–2093. doi: 10.1016/j.str.2013.08.026.

Palczewski K, Kumasaka T, Hori T, Behnke CA, Motoshima H, Fox BA, Le Trong I,  Teller DC, Okada T, Stenkamp RE, et al. 2000. Crystal structure of rhodopsin: a G protein-coupled receptor. Science 289(5480):739–745. doi: 10.1126/science.289.5480.739.


texts: How do genetic chimeras with different blood types not die?

texts:
If a person is a chimera and has two different blood types in his veins, how does he not die? Shouldn't the immune system attack one of the blood types?

  In 1953 a human chimera was reported in the British Medical Journal. A
  woman was found to have blood containing two different blood types.
  Apparently this resulted from her twin brother's cells living in her
  body. More recently, a study found that such blood group chimerism
  is not rare.


texts: Can dish soap really be used to kill ticks and fleas?

texts:
An answer at Pets suggested using dawn dish soap to kill fleas. I did a little looking around, and found several references supporting the idea.  Most of what I found was in 'selfhelp' and 'save a dime' type books and web sites. So while it seems to be a popular idea, I am unsure if it is an effective idea.

Is there any reliable science supporting the use of dish soap to kill fleas and/or ticks? If so what points in the life cycle would it be effective?  If it does work, how often would I need to use it to be relatively sure all the fleas/ticks have been through the appropriate life cycle and are dead?


texts: Do we get 1/4 of our genes from each grandparent?

texts: I know that we get half of our genes from each parent, but does it necessarily mean we get 1/4 of our genes from each grandparent? Or is it possible that we might get say 30% from one grandparent, 20% from other, 15% from another, 35% from another?


texts: What species of thermophilic prokaryote is present in hot compost that creates white mould like threads?

texts:
A method known as the "hot composting" method aims to create the right ratio of carbon rich and nitrogen rich materials in the pile in order to encourage thermophilic organisms to thrive in order to accelerate the process of making compost.

The following source 1 explains:

  Need optimum temperature of 55-65 degrees Celsius. At temperatures over 65 degrees Celsius a white “mould” spreads through the compost, which is actually some kind of anaerobic thermophilic composting bacteria, often incorrectly referred to as”fire blight”. (It appears when the compost gets too hot – over 65 degrees Celsius and short of oxygen. It disappears when the temperature drops and aerobic composting bacteria take over).

What specific species is this organism?

I say prokaryote in the question title as I'm aware it may be a bacteria or archaea. Many sources incorrectly refer to archaea as bacteria.

Hot Compost – Composting in 18 Days


texts: Online course on Plant Taxonomy and Physiology

texts: After following a course in Permaculture, I realised that if I want to get serious about it, I need to be able to distinguish plants. So I am looking for an online Video course on Plant Taxonomy and Physiology. My understanding is that it is a fairly standard course in basic Botany degrees, and since there are more and more school that put their material online it is quite possible that one of them might have placed this online too. Any suggestion?