texts:
Some actions, almost behaviour, exist that are common across a species. For instance, based on personal observation, human babies try to taste anything new they encounter until they are a few score months old. Similarly most dogs will go round-and-round before they finally settle down to sleep.

We probably use the term 'instinctive' to indicate there is no conscious thought behind that action, albeit the action is not a reflex either. Anyway, what causes instinctive behaviour? Is it genetic in nature? Are there some basic rules/behaviour hard-coded into our brains sort of like BIOS in a computer?


texts: Why can't neurons undergo cell division?

texts: Many cells in the human body can divide and reproduce, making healing possible. Neurons, however, cannot reproduce, which makes diseases affecting the brain particularly crippling. Why can't neurons divide - that is, what makes them different from "normal" cells? Are there any ways to artificially stimulate neuron cell division?


texts: How to obtain a list of proteins sorted by the ~1400 unique protein folds?

texts:
The databases CATH and SCOP both have around 1400 unique protein folds recorded from analysis of the PDB.  However, I do not see any method to access this particular data.

A list of each of the 1400 folds (just an id number, and/or a descriptor)?
For each individual fold (of the 1400), a list of PDB IDs for proteins which are known to adopt each individual fold?


texts: Cell type that expresses 90% of the genome

texts: Cells that are differentiated express the genes that are necessary for their own usage. I've heard that some cell type expresses about 90% of 30,000 proteins that are encoded in the genome. Can anybody tell me what this cell type is?


texts:
I have lost count of how many protocols I've seen, including those supposed to be professionally written (such as manuals that come with kits from well known brands, or methods sections of papers in respected journals), that outright fail to give unambiguous instructions. Some common examples are:

Give centrifuge speed in RPM instead of RCF, and not say what rotor or centrifuge it is.
Say to spin a sample at "maximum speed".
Use subjective time periods, e.g. "incubate briefly" (is one minute brief enough or does it have to be five seconds?)
Subjective quantities, such as "get a good amount of cells" (!!!)
Give time ranges without explaining the consequences of the choice, such as "5-10 minutes" (is it 5 or 10? which one???).
Say "mix well", without specifying if vortexing is okay.
Say "mix well, don't vortex", and don't explain what mixing technique I'm supposed to use.
Give urgent-sounding warnings, such as "don't touch the pellet!", without explaining what happens if I do it or how to fix it (do I need to start over? will I just get 5% lower yield?).
Give urgent-sounding warning, without explaining how to actually heed the warning ("dry the pellet, but do not over-dry it!")

It is in fact extremely rare that I ever see a protocol that has none of these issues. It almost never happens.

It is extremely important that scientific results be reproducible, and it seems like you are opening yourself up to a lot of trouble with an ambiguous protocol. What if somebody fails to reproduce your results, not because your experiment wasn't legitimate, but simply because you left out some crucial detail from the protocol you gave them? You would look bad, and for no good reason.

So why is it so common for protocols to be ambiguous? Is there some nuance to this that escapes me, or do people just not care? How do you follow a protocol that left out crucial information so as to be impossible to follow? Or are you supposed to have amassed a sufficiently vast reservoir of practical knowledge that you can draw on it to "fill in the blanks" on the fly?


texts:
My Campbell's Biology Textbook says the following:

  "For example, when an elk or other mammal moves up into the mountains from sea level, physiological changes that occur over several days facilitate activity at the higher elevations. The lower oxygen concentration in the air stimulates the animal to breathe more rapidly and deeply. It therefore loses more CO2 through exhalation, raising blood pH above its set point.

I was wondering if anyone could explain why blood pH increases as your altitude increases? I know that an increase in pH is a sign of less H+ ions in the blood, but what exactly causes you to lose the ions when you're exhaling CO2?

Thanks!


texts: Head transplant feasibility - Project HEAVEN-GEMINI

texts:
There is a news circulating that in the next two years, Dr. Sergio Canavero, of the Turin Advanced Neuromodulation Group (TANG) in Italy, will perform the world's first head transplantation. A procedure which will require

  150 surgeons and nurses approximately 36 hours to complete

and after which the patient is held in coma during recovery

  The recipient will be kept in a coma for around 3-4 weeks, says Dr. Canavero, during which time the spinal cord will be subject to electrical stimulation via implanted electrodes in order to boost the new nerve connections.

Is this even feasible? If it can be done, does that imply that humans can live for a long time, if they can find a compatible donor ? What requirements are there for compatibility?


texts: What is the mechanism by which seeds stay alive while in storage?

texts:
I know folks who store seeds for months and sometimes a year before planting them. What is the mechanism by which they stay alive?
Also some associated questions:
How do the cells in the seed stay alive without resources for so long?
How long can the seeds stay alive in storage?
Does storing them long affect their growth?


texts: Can the excessive consumption of mineral water lead to kidney stones or other health issues?

texts: I heard that drinking too much mineral (bottled) water could lead to problems such as kidney stones because of the high amount of minerals in it. Is it true? If so, what is considered to be excessive?


texts: If my uncle and I both got our DNA tested and compared ancestry results, should we have 50% or 25% similarity? I get normally it would be 25% but since the mitochondrial DNA and Y chromosome are (mainly) used to figure this out using the test we did, shouldn't we share the same exact maternal DNA since it's my mom's brother and that doesn't recombine or anything and they got it from their mother? I just want to know if this is a different genetics problem than normal. Thanks!


texts: When does exposure to an allergen increase / decrease allergy?

texts:
In immunotherapy a person is regularly exposed to an allergen to decrease the allergy. Yet apparently "repeated intranasal challenges ... induces robust allergic airway inflammation, " [0]

So when does exposure to an allergen cause allergy induction vs hyposensitization?

[0] http://www.researchgate.net/post/Which_is_the_best_way_to_sensitize_mice_to_house_dust_mites


texts: Are harmful gases abiotic or biotic factors in our environment?

texts: As we all know, harmful gases play a negative role in our society and our environment. Are these gases playing as abiotic or biotic factors in our lives?


texts: How is vitamin B12 stored in the body although it is water-soluble?

texts:
Vitamin B12 is stored in the liver for a long time.

How is it stored?


texts: Is there a map of the individual motor axons in the limbs?

texts:
As of right now, I can only find a map of nerve fibers, but not necessarily the individual neuron axons.

For example, here's a map of the nerves in the arm and hand.
http://www.innerbody.com/anatomy/nervous/arm-hand


texts: Does a phenotype include the presence of a recessive gene

texts:
I am trying to understand what exactly a phenotype is to try and understand a genetics database. (Ie I don't really know very much about genetics at all)

I've been reading through wikipedia on what a phenotype is and from what I can gather it is an observable trait which may be impacted by a specific gene.

What I would like to know is if you were looking for the presence of a phenotype such as red hair, would characteristics like not red hair and carrier of red hair also be phenotypes?

For example the following table is named Phenotype,

+------+------------------+
| Code |   Description    |
+------+------------------+
| RR   | Red Hair         | this makes sense with my understanding of phenotype
| RN   | Red Hair Carrier | this doesnt
| NR   | Red Hair Carrier | this doesnt
| NN   | No Red Hair      | this doesnt
+------+------------------+

The whole code column looks like it represents a gene not a phenotype


texts: Why is neuronal firing rate proportional to axonal diameter?

texts: I know that a larger axonal diameter results in faster speed of action potentials due to reduced resistance. However this doesn't explain why the firing rate of neurons is proportional to neuronal diameter. Is it because higher spike rates require larger capacitance (since each spike charges the neuron) meaning a larger surface area and diameter of neuron is needed?


texts: Where do the electrons and protons formed from biological reactions go?

texts: In a reaction like disulphide bond formation protons and electrons are released. These particles are presumably damaging in high levels. What systems are in place to prevent a build up of electrons and protons?


texts: What is internal symmetry in membrane proteins?

texts:
I have come across the term "internal symmetry" in the context of membrane proteins, but have never found a satisfactory definition.

I'm struggling to figure out exactly what this term means... What plane is this symmetry seen on? Is it dimers that are symmetrical or can a monomer also be internally symmetrical?


texts: Previously frozen papaya seeds sprouted. How will it affect the plants?

texts:
I thought about asking this on Gardening SE, but it seems to me as a technical subject which requires biological expertise to answer. This is not something that usually occurs for gardeners, so I don't think anyone there would have experience with it.

A bunch of seeds from a papaya fruit were put in the refrigerator. They were taken straight out of the fruit, along with pieces of pulp, sarcotesta and all.

The seeds ended up below zero. Probably only by a few degrees, at worst. They would have been in that state only for a few hours, at most. However, ice crystals had formed on them, and the pouch had hardened a little bit. I then thawed them. All that happened on May 19.

Well, I decided to plant them, as an experiment. And a few days ago, they started sprouting.

I actually have more seeds from the same fruit, which have not been exposed to below zero temperatures.

Now my question is: If I let these plants become large trees, will they in any way be different from the normal seeds? (Assuming they get equal treatment.)

I thought the seeds would die, so I was surprised when they sprouted. But since this is a tropical plant, could the negative temperatures have damaged their DNA in any way? Or had some other detrimental effect on them? Or can I expect these plants to be exactly like the other group? (Except for individual variations unrelated to the freezing, of course.)


texts: Why does BLAST use Local alignment, not Global alignment? And when would a global alignment be useful?


texts: How to interpret the relationships of PTMs from BioGRID's data

texts:
On BioGRID Database, PTMREL is a file that describes relationships of the PTMs (Post Translation Modification) tabulated in a PTMTAB file.
I have several issues with this file.

Foremost, I am not sure how to interpret the 'relationships'.

There are two columns 'Relationship' and 'Identity' that supposedly describe the relationships of PTMs.
    Relationship. A plain text descriptor of the type of relation represented. (Unique values: ['-', 'kinase', 'phosphatase'])
    Identity. A plain text descriptor of additional identity details if available. (Unique values: ['catalytic', 'regulatory', 'PTM'])

Lets say, a gene has a relationship (in in PTMTAB file, column 'Has relationship' is True) and in PTMREL file it is 'kinase' (in PTMREL file column 'Relationship'), does that mean that the gene is kinase or it is phoshorylated by a kinase?
Also what does it mean if the gene is additionally 'catalytic', 'regulatory' or a 'PTM' (in PTMREL file column 'Identity')?
Here's BioGRID's wiki page describing (but not detailing) the file format of PTMREL file.
https://wiki.thebiogrid.org/doku.php/biogrid_ptmtab_ptmrel.

If PTMREL contains data associated with PTMTAB file, why not simply combine it with PTMTAB file? Without knowing how to interpret the relationships of the PTMS, the users too, can not combine the two files.

Additionally, there are PTMs included in 'BioGRID TAB 2.0' too, and the number of PTMs (for a species) in that file are not the same as in PTMTAB file(!).

I understand that BioGRID provide this data 'WITHOUT ANY WARRANTY'. But still, since BioGRID is the most unified and constantly updated resource of gene interaction networks, users should know about basic usage of the data.
UPDATE:
After some data explorations, I could guess the meanings of the data.
If Relationship is '-' -> Identity is always 'PTM'. So, these are the PTMs that do not have known relationships.
If Relationship is 'kinase' or 'phosphatase' -> Identity is 'catalytic' or 'regulatory'. Now, here, I am not sure what do 'catalytic' or 'regulatory' mean.


texts: Does the formation of water inside the mitochondrial matrix help contribute to the proton gradient during the electron transport chain?

texts:
Does the synthesis of water in the final step of the electron transport chain significantly increase the electrochemical gradient across the matrix? I understand that pumping protons out of the matrix clearly increases the positive charge in the intermembrane space, but the chemical reaction in Complex IV O2 + 4H+ + 4e− → 2H2O also reduces the protons in the matrix by binding them in water.

Since ATP synthase relies entirely on the electrochemical proton gradient, it seems like this might be worth mentioning, yet I haven't seen this explicitly explored in any textbooks. If there is any literature about this topic, I would love to see it.


texts: Is one DNA molecule same as one chromosome

texts: Is one DNA molecule = one chromosome or is one DNA molecule = all the chromosomes, ie, all the genetic material in our cells? I have googled it but  I am not getting clear answers ?


texts: Thermodynamics of spontaneous protein folding: role of enthalpy changes

texts:
I'm trying to get clear why protein folding occurs spontaneously.

$$\ce\Delta G=\Delta H-T\Delta S$$

According to thermodynamics the ΔG should be negative for a process to occur spontaneously.
When a protein folds the ΔS (Entropy) is decreasing, because the protein gets more ordered. However I think the forming of the bonds (disulfide and other weak interactions) counterbalance this unfavourable rising entropy by forming an enthalpy (ΔH) which thus would result in a negative ΔG.

However I saw some other explanation online which didn't apply the Gibbs free energy formula to the protein but instead to the water. Because the water is more ordered when the protein is unfolded it would be favourable according to the second law of thermodynamics to fold the protein because after folding the water molecules can move more freely --> higher entropy -->negative ΔG --> spontaneous folding.

So my question is which of these two (or maybe both) are the cause of the spontaneous folding of proteins?


texts: Do large animals often evolve into smaller animals?

texts:
There are several examples where the largest animals were killed off preferentially due to a major ecological shift:

The KT extinction event
The Holocene extinction, as well as the major megafauna humans killed off

The common ancestor of modern mammals is thought to be "shrew-like" in size, and it differentiated into most of the large animal species in the world today.  I imagine that a similar statement can be made for dinosaurs.  In general it seems that a major extinction event is likely to be best weathered by smaller creatures which can later, over time, increase in size to fill the niche that larger animals, and evolution dictates it will be profitable to do so.

Does this limit large animals to only the branches of the tree of life?  Any given set of (Multicellular) species obviously share a common ancestor that is much smaller than them.  Is it possible for many species to share a common ancestor that is considerably larger than any of them?


texts: Why should or shouldn't we allow the human body to take its natural course?

texts:
For example, when you are sick but don't feel thirsty, this could be due to baroreceptor reflex that is attempting to readjust salt and water balancing.

Why shouldn't a patient be left thirsty and let the body to adjust until he or she feels thirsty again?


texts: Identifying internal structure of dissected prawn

texts:
Note: Some of the images might be disturbing.

I have dissected prawn for the first time. Would like your help in identifying some structures
.

This is the dissection of the posterior part of the prawn. What is this blackish structure in the middle ? This structure becomes whitish farther down. Then, it forms a small sac like structure and then becomes thin again. This whole structure appeared just after I cut the exoskeleton. It is directly above the muscles.

I think that this is it's alimentary canal and the black area has digested food in it. The sac like structure might be the rectum.


texts: Protein folding, extra dimensions and bio-mathematics

texts:
One metaphor that I have found to explain how proteins fold so quickly to a native shape is that of the blind golfer.

I have made a video to illustrate this metaphor. This shows how the shape of a slope can determine precisely where individual elements will end up.

The video represents many zero-dimensional points each following its own one-dimensional path down a three-dimensional slope to end up in a two-dimensional arrangement. Or almost: the one-dimensional paths are curves in three-dimensional space, the final resting surface is not flat, and one marble sits on top of three others.) The movement takes place through the fourth dimension of time.

Proteins form three-dimensional shapes, so the "slope" that their components slide down must be in an extra dimension.

Atoms have been observed to jump through a crystal lattice, without any indication that, in travelling from their start point to their end point, they pass through the three-dimensional space that we can observe. Is it conceivable that the component parts of a protein move through an extra dimension as the protein "folds"?

There are very simple protein chains whose native folded shape is well known. Is there any data available to suggest what path the different molecules in the protein follow during the folding process? Or do they appear to "jump"?

I imagine that it would be possible to create a mathematical model in n-dimensions to describe the simplest "slope" that the protein molecules could follow as the protein collapses into its native state.

What mathematical work is currently being done in this area?


texts:
I performed a WB using plasma rats and monkeys samples with anti ubiquitin K-48 antibody. In every sample the antibody binds something and it appears a specific band that seems to be 71kDa. When I used anti-ubiquitin unspecific antibody(just to see if I get the same results) same bands appears. It cannot be ubiquitination because the molecular weight. How can I explain the both antibodies bind something that I dont know?

Thanks


texts: Suitable introductory book on Bioinformatics for a computer scientist?

texts:
Do you have any suggestions on a suitable introductory text on bioinformatics for a computer scientist? Any recommendations with pros and cons of different books would be appreciated. I'm mainly looking for a brief introduction since I'm a novice to this field.

I found some books like

Systems Biology by Edda Klipp,
Introduction to Bioinformatics  by Arthur Lesk
Bioinformatics For Dummies
Bioinformatics and Functional Genomics by Jonathan Pevsner
An Introduction to Bioinformatics Algorithms by Neil C. Jones and Pavel A. Pevzner

I would like to develop software related to sequencing applications, so any suggestions should ideally aid in this goal.


texts: Is the missing "life-ingredient" in today's Earth's existence the reason why we cannot recreate life?

texts:
As far as I know, there was no report of "life" popping up in a lab or in nature so far.

Everything that we know is only some copy with similarity to previous life-forms.

We certainly can mix some amino acids and stuff, and even some of the chemicals can retain some structure for a certain time and even form some proto-RNA-like structure (not sure how they called it in one document I have seen), but it's very very far from a living organism.

Does it mean that life cannot be "sparked" in today's Earth like conditions or, was it not even sparked here to begin with? I have read, as many others have done, this article: New research supports an idea that the Red Planet was a better place to kick-start biology billions of years ago than the early Earth was. They argue that you need molybdenum to create life-like structures and that it's not common in the right form on Earth.

What do you as biologists think about the statement that life cannot evolve on Earth because the conditions in the beginning of the Earth were not good for life to develop.


texts:
DNA, has a deoxyribose sugar — phosphate backbone with the purine and pyrimidine bases, adenine, cytosine, thymine, and guanine connected to the deoxyribose sugar. (The base–sugar molecules are nucleosides, and those with phosphate, nucleotides.) In the double helix structure of DNA the two strands are twisted and connected by hydrogen bonds between the bases.

How is this "twist" created in the cell, and why is it necessary?


texts: How do we regulate the production of proteins when designing plasmids?

texts:
I think it should be no surprise that I, as many others, am interested in the new COVID-19 vaccines being developed. In my region of the world there are two mayor candidates. One is mRNA based and one is, as far as I understand, plasmid based.
I have a passable understanding of the mRNA based vaccine.
I also know what a plasmid is, and how it is transferred between cells, but my understanding is otherwise limited.
As far as I understand we want the plasmid to be "unlooped" and grafted onto our target cells DNA. This, as far as I reckon, should enable the cell to produce whatever protein the plasmid coded for. In vaccines this lets us device anti-measures (vague because of my lack of knowledge) against the virus... But, how do we regulate the production of these anti-measures? Can we include a "regulator" for the production in the plasmid, so that the modified cells only produce the proteins when the virus is present? Or do we just let the cells continuously produce the anti-measure proteins, regardless of their necessity?
My main interest here lies in where the permanency of the vaccines induced changes lie. With the mRNA vaccine I understand that the permanency lies in the regulated immune system, with other cells being otherwise unchanged after the mRNA decomposes. Regarding the DNA/plasmid vaccine I'm still unwise.
Thank you for your time, and happy holidays.


texts:
During the differentiation of B cells in bone marrow, recombination occurs in light chain and heavy chain genes to produce a single type of functional gene which determines the type of light chain and the heavy chain produced by that B cell.
Therefore, a single B cell and its generation displays a single type of antigen receptor on its cell surface.

My question is-
Recombination will occur in both the copies of the light chain gene present on the homologous chromosomes (same with the heavy chain gene).

So, the combination produced on the homologous chromosomes should be different.
Is it really so?  And if not, then how come they are identical?


texts:
Why do humans "need" to cook animal meat?

It seems there's an aspect of safety to it: are other animals (eg, house cats, dogs) not vulnerable to the same diseases we get from modern food processing of meats?

But it also seems there's something else to it: is raw animal flesh is harder to digest for us, no matter how fresh or processed?

I've read so many conflicting things about it, like how cooking is really a way to avoid disease, but that the human body is capable of processing protein from raw meat just the same. An example is how other countries eat raw meats that Americans would not. But then I've also read things about how cooking meat is what allowed humans an energy advantage early in our development as a species (I'm not clear how more calories are "unlocked" by cooking) or how denatured protein plays some role in usability. I also know that my person experience with raw meats doesn't help me understand it, because sushi seems to be fine but raw eggs will upset my stomach.


texts: Does rainwater contain many fewer micro-organisms than river water?

texts:
From watching many documentaries on micro-organisms, I can tell water typically contains quite a lot of them.

But what about rainwater? (before it hits the ground). I know nothing about any micro-organisms that live in the sky or clouds. Does rainwater contain fewer, and less dangerous, micro-organisms?


texts: What is this giant insect that just bounced off a second-floor glass door?

texts:
At about 11 pm, I heard a loud impact on the nearby glass door to a second-floor balcony. I thought it might be an acorn but it'd be a very unlikely angle - it'd have to be thrown from below or be a very strange ricochet.

So I looked and encountered this rather impressive creature recovering on the balcony:

Those planks are six inches wide.

I've never seen one of these before. What is it? Are those giant serrated appendages on the front mandibles or antennae?

I expect it's not as hazardous as it looks, but is there any risk of it biting people or pets?

Do they routinely launch themselves two stories into the air, or would it have crawled up and then just bounded from the balcony floor?

Location: Southern Oregon, USA.


texts: What causes random long white body hairs?

texts:
I'm sure many of you have experienced this - you scratch your back or brush your hand over your arm and find a ridiculously long thin white hair, sometimes as long as 3 or 4 inches. I know a few people who get these quite frequently, and anecdotal evidence seems to suggest they almost grow almost overnight. A quick Google search for "single long white hair" throws up plenty of references to them, and various beauty advice, but I'd like to know the biology behind them.

What triggers abnormal body hair growth?
What causes these hairs to grow so much longer than other "normal" body hairs in physical proximity?
Why are they so thin and white compared to other body hair?

My primary hypothesis is that the hair cell grows rapidly in an uncontrolled manner, similar to how cancer might, and that the unusual appearance is due to the cells being starved of nutrients. I may be completely wrong, though.

I'm mainly interested in humans here, but if more in-depth research is available on animals that'd be interesting too.


texts: Is stereo olfactory ability restricted to humans?

texts:
Most animals I see around seem to have two nostrils - humans, snakes, birds, fish .. and so on. From reading online I see that 2 nostrils provide a stereo olfactory effect. This stereo effect is caused by the difference in flow of air through the nostrils.

Does this stereo effect apply only to humans? Are there any animals that have a different number of nostrils? Say, more than 2, or less.


texts: Are molecular machines encoded in the DNA?

texts: I don't know much, if anything, about molecular biology. I watched the "inner life of the cell" on Youtube which triggered my curiosity about how these molecular machines came to be. My simple understanding is that if these molecular machines are encoded in the DNA, then they are "evolve-able" by mechanisms such as natural selection. Is that case? And if so, can we identify which part in the DNA sequence have the encoding for these molecular machine such as the Kinesin? Do molecular motor machines get synthesized by the RNA as well?


texts: Hi I saw this bird near my school canteen in Singapore in Spring. Can anyone identify the species of this bird? Thanks in advance!


texts:
Sorry if this is too much of a soft question or if it is too broad for this site.

As a person who has much more experience with math than biology, I've always been really interested in the mathematical side of biology. As I study math in biology, however, I am left with the question of "how is this actually useful?"

What kind of unique insight can mathematical models give us about biological systems that we couldn't just find experimentally?


texts: insect paralysis in response to predator echolocation frequency

texts: I remember a case in which some insect had evolved an adaptation in response to a predator's (bat's?) echolocation frequency. In mid-flight, it's wing muscles would become paralyzed and it would suddenly drop like a stone directly towards the ground. Does anybody know what this insect is? I thought it was a moth or a mantid.


texts: Is there a biological environment that we can we assume glutamate exists as glutamic acid?

texts:
In the body we almost always assume that glutamate exists as glutamate rather than glutamic acid. It is so commonly glutamate yet glutamic acid and glutamate share the abbreviations of Glu and E. From the wikipedia page:

  The side chain carboxylic acid functional group has a pKa of 4.1 and therefore exists almost entirely in its negatively charged deprotonated carboxylate form at pH values greater than 4.1; therefore, it is negatively charged at physiological pH ranging from 7.35 to 7.45.

Glutamic acid:

Glutamate:

Given that the pKa of glutamate is 4.1, is their any biological situation (a cell type, organel etc.) that glutamic acid is preferred?

Additionally, does this have any large biochemical implications, or is that outweighed by the (relatively speaking) "extreme" acidic environment?


texts: Does the Parasympathetic Tract of Colon Sigmoideum Travel with Nervus Vagus and its Nucleus Dorsalis Nervi Vagi?

texts:
I have the following tractus now:

  nucleus parasymphaticus sacrales -> nervus splanchnic -> ganglion
  terminalis -> colon sigmoideum

The tract is parasympathetic.
It suggests me that it should travel along CN 9 or CN 10, most likely with CN 10.

Does tractus colon sigmoideum travel with CN 10 and its nucleus dorsalis nervi vagi?


texts: Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?

texts:
In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows:

Say we have the minimum charge input, "X", necessary to depolarize the axon initial segment of Neuron 1.

Now, we have Neuron 2, which has a larger soma. Will this same input X be sufficient to depolarize the axon initial segment of Neuron 2?

I am trying to explore how physical concepts like capacitance manifest in biological systems. Neuron 1's soma (approximated as a sphere) presumably has a lower capacitance than Neuron 2's soma (approximated as a sphere), due to the difference in cross sectional area of the somas. Therefore, I would assume that Neuron 2's axon initial segment requires greater input to depolarize than Neuron 1's axon initial segment.

Is this simplistic idealization of somas actually observed in experiments?


texts: Why do orcas eat only the tongue of whales, liver of sharks, etc.?

texts:
I noticed that although killer whales are clearly the top predator living in the present oceans, some of them appear to be very picky with their meals.

After spending hours hunting down a whale, pretty much the only thing they eat is the tongue. I'm not sure how that satisfies their hunger, especially considering how long and arduous the hunt took.

Then there are orcas hunting sharks and eating virtually only the liver. For such a dangerous prey, is such a delicacy worthwhile? I mean, what happens if they're starving after the hunt?

Any relevant comment will be greatly appreciated. Thanks!


texts: Effects of smoking tobacco compared to inhaling other smoke

texts:
How much less dangerous is breathing smoke from burning wood and coal compare to smoking tobacco?

Edit:  Sorry.  I should have made the question clearer.

If this were an experiment, it would be set up like this.  Subject 1 is a control, so he is exposed to smoke from burning tobacco for a year.  Subject 2 is exposed to smoke from burning maple leaves for a year.  Subject 3 is exposed to smoke from burning pine needles for a year.  The other subjects continue in this fashion, being exposed to smoke from many different sources.  The rats are examined for lung cancer through this year and for the remainder of their lives.  What would the expect results of this experiment be?


texts: How do plants prevent infection from retroviruses?

texts: Why are plants not affected by animal viruses such as retroviruses? What prevents them from being infected?


texts: Why is it that drinking caffeinated tea does not help one to stay awake?

texts:
I have never felt after drinking tea that I can have the power of being able to work late at night. Neither have I felt that it helps me to be awake while working or keeping eyes opened while I am not in mood for sleeping.

Drinking tea, then, does not helps me to stay awake.

Is it the nature of the tea itself, or does it have to do with how the body processes caffeine?


texts: I know the clavicle of the cat floats freely as opposed to be attached as in humans. This is supposed to allow them to be able to squeeze through spaces, according to a quick google search. But how does that allow them to move through tight spaces in comparison with humans?


texts: Is there such a thing as subclinical immunity?

texts:
This current CNN article suggests exposure to very low doses of a virus may be protective.  However, I recall reading a flu study that found protective antibodies were only produced in symptomatic individuals.
Question:  Suppose a group of animals (e.g. humans) is exposed to small doses of a virus, and you exclude any individuals from the group that show symptoms or antibody titer significantly above nonspecific background.  What is known about whether these individuals will have a lower rate of symptomatic infection, seroconversion, or death after a second exposure to a standardized infectious dose?
Addendum:  I hadn't wanted to put a specific model into people's minds, but given the lack of response I should go into what I was thinking a bit further.  Suppose one individual epithelial cell in the nose were to be infected with an RNA virus, and either the virus is defective (such as a frameshift) or the cell responds so quickly and effectively via the interferon pathway that it is unable to assemble infectious particles.  If the interferon response leads to vigorous antigen presentation and cytokine release, could enough T cells interact with the infected cell and/or phagocytic cell(s) that take up and present its antigens, that one of them could find a match to its T cell receptor and become activated?  My guess would be that even a single helper or cytotoxic T cell division, if it's the right cell, might put the adaptive immune response many hours ahead of schedule relative to the replication of the next viral particle to be encountered, which could be enough to make a difference.  But I don't know immunology nearly well enough to be sure that is logical, and biology is free to disagree with logic when it pleases.


texts:
I found a tiny, white animal in my mouth on the morning of June 28, 2015, in Toronto, Ontario. Luckily I don't seem to have hurt it. I was eating some sunflower and pumpkin seeds at the time. I believe that's how it got there.

The pictures include a toothpick and a Canadian cent to give an idea of its size.

I also took a video of it crawling around. I will post it if the pictures are not sufficient for identification.


texts: Do individual (free) nucleotides base-pair with other free nucleotides?

texts: I had a student ask me about this and my google-fu let me down. He asked if individual nucleotides (not in a nucleic acid) base-pair with their complementary nucleotides, essentially forming many dinucleotides. I would think this would occur, but have no evidence one way or the other. If it does, how does this impact the usage of nucleotides in nucleic acid synthesis? I'd assume they have to be broken apart first...


texts: In a fitness landscape, is fitness relative or absolute?

texts:
I was asked if the fitness of a fitness landscape is absolute or relative.

Fitness landscapes are usually graphed with a fitness function that uses either phenotypes or genotypes in relation to fitness or one of its component.

More specifically, if the fitness measured is survival, and it's computed based on a quadratic model, does that means that every individual survival probability is an absolute measure of "fitness" (survival)?

Or since it's computed from a model, would it be better to find the relative contribution of a variable on the predictor in the model and say that the "fitness" is relative to a trait if it's computed with multiple traits?

How does the mean fitness of the population influence the model, which will determinate the fitness of all individuals? Is this "mean contribution of the population's fitness" a relative measure of fitness?

My specific questions are:

What type (relative vs absolute) of fitness is shown in a fitness landscape?
Does the type of fitness change if you change way to model it (For example, I want to know specifically for a quadratic model vs a spline)?
Does the type of fitness change if you change way to model it (For example, I want to know specifically for a quadratic model vs a spline)?
When using a mark recapture model (you use the survival of each individual to find a fitness function) is the survival estimated by the model relative or absolute? Does the mathematical formulation of the model changes something?

In the image below, I've graphed all the points (black line) and I've removed the 3 lowest values of y for the 3 largest x values (red line). If I was calculating the fitness of the individuals with or without the 3 smallest points for the 3 largest x values, then the fitness of all the other individuals would be affected (except at x~38 and y~38).

x = c(1:100,101,102,103)
y =  c(x[1:100]+rnorm(100, sd = 6), 50,60,30)

x = c(1:100,101,102,103)
y =  c(x+rnorm(103, sd = 6))

summary(lm(y~x))
plot(y~x)
abline(lm(y~x),col = "red")
points(38,38,col="blue")

Another example with crossbills:

Would you say it's relative or absolute fitness. Here the fitness measure is "performance" of eating certain types of seed.

In this article they are saying (Morrissey & Sakrejda 2013):

  Regression analyses are central to characterization of the form and
  strength of natural selection in nature. Two common analyses that are
  currently used to characterize selection are (1) least squares–based
  approximation of the individual relative fitness surface for the
  purpose of obtaining quantitatively useful selection gradients, and
  (2) spline-based estimation of (absolute) fitness functions to obtain
  flexible inference of the shape of functions by which fitness and
  phenotype are related. These two sets of methodologies are often
  implemented in parallel to provide complementary inferences of the
  form of natural selection.

Are least squares-based approximation of the individual always computing relative fitness surfaces? For spline, is it always absolute values?


texts: How does C-DNA have 9.33 base pairs per turn? The number of base pairs should be quantised. How can it be a decimal?


texts: Use numbers or algebra when introducing an evolutionary biology concept?

texts:
I'm working on an (approximately 20 pg) evolutionary biology paper for submission to a journal.  The paper introduces a couple of strategies (I use "strategies" loosely; they can be carried out by unconscious individuals).  I have described the strategies verbally.  However, I have also tried to offer additional clarity by putting the strategies into some numerical form.  I would imagine that there are many possible models that could be used to test these strategies.  I am using one model, with so many simplifying assumptions that even if I were to carry through an algebraic treatment under this model, it would be of little use in giving a general representation of when the strategies can be selected. My goal is to go through an example under the model in order to show how the strategies are supposed to work, not the conditions under which they can be selected.

Is it easier to follow an example with numbers or with algebra in place of those numbers?


texts: Can emulsion test be used to detect phospholipids?

texts:
The emulsion test- causes a white cloudy colour when lipid is dissolved in ethanol and then water added.
Can this be used for phospholipids? I am aware that they are polar so may arrange in a circular formation in water but would the test still work?

Thanks


texts: Gene copies vs. gene paralogs - what's the difference?

texts:
I'm trying to get into the theory and practice of gene copy number variation (CNV) analysis, but there is something basic confusing me, which I couldn't yet figure out. Sorry if this is a dumb/trivial question - would appreciate your help anyway.

My confusion is regarding the terms 'gene copy' and 'paralogs'. As far as I understand, paralogs are created when a gene undergoes duplication (never mind by what molecular mechanism), and then starts accumulating mutations as evolution proceeds. So, if gene X was duplicated to create another X, and then X changed to become X', are X and X' considered copies of the same gene, or are they paralogs? Is it a matter of applying some threshold on the sequence similarity between X and X', so they are considered copies up to the point where they diversify enough? Or maybe gene copies are expected to be perfect duplicates? If so, I'd guess that finding such gene pairs is very rare... Maybe it's a matter of function, so once X' gets a different function from X (neo-functionalization), it is considered a paralog? This is a rather complex and difficult to measure definition...
To make things less theoretical and more practical, lets limit the conversation to the context of whole genome sequencing analysis. Let's say that I am annotating a newly-assembled genome, and let's assume that the assembly is good enough so gene copies are not collapsed, but rather are located in their respective genomic positions. How would you look for gene copies and paralogs, and how do you make the classification?

Could anyone clarify this point for me, or refer me to relevant literature?
 Thanks a lot!


texts: Is there a way to see what representations are currently displayed in PyMOL?

texts:
I am using PyMol to visualize .pdb protein structures.

I show/hide representation a lot, and sometimes I get confused with what representations are currently displayed. So I end up with doing a lot of hides (basically trying to hide each representation).

Is there a command which shows me what representations are currently used.

For instance if I have used

show ribbon
show lines
show mesh
hide lines

and than use some sort of showRepresentation
it will return me ribbon, mesh


texts:
I've seen a lot of articles claiming that alcohol has a very bad impact on athletic performance. Examples include, but are by far not limited to:

http://oade.nd.edu/educate-yourself-alcohol/alcohol-and-athletes/
http://www.theguardian.com/lifeandstyle/the-running-blog/2014/apr/23/how-does-alcohol-affect-athletic-performance
https://www.acsm.org/docs/current-comments/alcoholandathleticperformance.pdf
http://www.athletestore.co.uk/wordpress/wp-content/uploads/2013/01/The_Effect_of_Alcohol_on_Athletic_Performance.7.pdf

I'm of course not in position to doubt those articles, as I'm a no expert in biology.

However. There is one thing I find odd.

Namely. These articles themselves claim that alcohol is widely consumed even by the highest ranking athletes. I mean, if alcohol has that bad effects... then it couldn't have been consumed by highest-ranking athletes, as alcohol-consuming athletes could never rich the heights of the tops of proffessional sports?

Also. AFAIK mediaval knights were not abstinents by any means, they were drinking beer and wine and mead to excess; yet they were able to bring their strength, stamina, etc, to an extreme.

This is not something I wish to argue about; rather, this is something I fail to understand.

BTW. This question is not personal; I don't do sports and I very rarely drink. And I regret the former, not the latter.


texts: Why is the pressure pulse bigger after exercise?

texts: Right after exercise, is the amplitude of the pulse smaller or bigger than resting period? And why is that ?


texts: Do rare earth metals actually repel sharks?

texts:
Stroud claims that sharks are effectively repelled by the use of rare earth metals in the water. There has even been a patent issued by the same author for rare earth-wrapped fish hooks to reduce the shark by-catch.

Apparently these metals work by generating an electric current that repels sharks via the shark's electric sensing organ.

Is the repellent action of rare earth metals scientifically confirmed? And if so would it be effective even on the largest and aggressive white sharks?

Also if effective why haven't dive equipment manufacturers developed shark repellent devices for sport divers?


texts: Are antibodies removed before blood transfusion

texts:
I am an O blood group person meaning, I can donate my blood to all as I don't have any Antigen A and B. But my body does contain antibodies A and B right?
If they were along with the donor blood, wouldn't they cause clotting with the recipients blood?
We spent a whole period over this. My teacher said they probably remove the antibody before transfusion, but I couldn't find much info on that. I postulated that these antibodies can not work outside the donor body for some reason.
Thanks for the help


texts: How do human cells respond to mechanical pressure such as heel contact during walking?

texts:
Basically, I'd like to do a full accounting (inventory, assets, liabilities) of a human cell under mechanical pressure.

For example, if in steady-state, does the cell consume more or less energy under pressure?

Is membrane transport affected? For example are ion gradients or cell fluid levels changed in response to pressure. If there is a change, how does the cell sustain this over a period of time.

Conversely, if a gradient is disturbed by mechanical pressure, what are the energetic consequences? Does the system behave like a spring such that if the concentration gradients are perturbed out of balance, there is a restoring force (say passive) that will rebalance after the mechanical pressure is removed?

Any focused sources or references would be greatly appreciated.


texts: Do cortical cells in root have higher water potential than endodermal cell solution?Or is it the other way round?

texts: Well, water normally passes from root hair cells to cortex to endodermis, and from there to the xylem vessels. All of this occurs down the water potential gradient by apoplastic or symplastic pathway through these cells. I was wondering how water potential differs in each of these cells for water to be transported. BTW I'm confused why my teacher said that the water potential in xylem vessels(the tracheids) is highest among all the cells I mentioned. Then how come water can move down the water potential gradient?


texts: Are there epigenetic effects in the regulation of human height?

texts:
Development of human average height
Human average height has fluctuated significantly throughout history. For instance, in the last 100 years or so, it has increased sharply by about 10cm. OWID (Our World in Data) has data and figures on, among other measures, the average height over the last 18K years, average male height by country over the last 200 years, annual change in average male height, and annual change in average female height.
Regulation of human height
Already the genetics of human height seem to be complicated and to involve a large number of different genes (and hundreds of loci) according to, e.g., this article by Lettre (2011). However, since the time spans are too short for significant purely genetic effects, there must be either developmental or epigenetic effects at play or both. Developmental effects have been linked to socio-economic status, perhaps via steady and good nutrition before birth and during childhood. This paper by Komlos (2007) (without paywall here) shows data for English youths in the 1700s and 1800s by socio-economic status and finds a height gap of up to 22.6cm, his sample sizes are a couple of thousands for the lower-class group and less than that for the upper-class group.
Epigenetics human height
Carey reports in her book "The Epigenetics Revolution" (2012) that people born after the Dutch Hunger Winter would not only remain small for their entire lives but that there was still a significant difference in their children, born decades later. She does not seem to refer to height differences though (I guess?), but to differences in the risk to develop certain diseases as reported in this paper by Heijmans et al. (2008) (not sure if there's a paywall; same paper is also here). They trace this to differences in the expression of a certain gene (IGF2) because of hypomethylation of that region.
Since other phenomena are thus shown to be subject to epigenetic effects, it is possible that the regulation of human height is too. To be clear, I am not aware of any study that suggests this (or investigates this). It would certainly be very difficult to identify, so I suspect this has not been thoroughly investigated. Note that the epigenetic effects shown in Heijmans et al. (2008) could only be shown because of the very specific conditions of the Dutch Hunger Winter, a short but horribly severe famine with intact medical records. But I am hoping there is some information out there.
So my question is
Are there indications that epigenetic effects may be present in the regulation of human height and its rather interesting development in recorded history? (Or is this unlikely, e.g. because the variation is sufficiently explained by other factors or because studies have tried and failed to find epigenetic effects? Or has this not been investigated so far?)


texts: Can domestic breeding be considered evolution?

texts:
Domestic breeding of animals (and plants) by humans seems to match some of the definitions of evolution I have been able to find:

"a process that results in heritable changes in a population spread over many generations." (the TalkOrigins website)
"cumulative inherited change in a population of organisms through time leading to the appearance of new forms" (Merriam-Webster)
"Changes in the heritable attributes of populations of organisms over time" (this SE's 'evolution' tag info)

But other definitions seem to be less of a fit:

"the way in which living things change and develop over millions of years" (Cambridge)
(domestic breeding does not take millions of years)
"The process by which different kinds of living organism are believed to have developed from earlier forms during the history of the earth" (Oxford)
(Does breeding lead to different 'kinds' or organisms?)
"The gradual development of more complex organisms from simpler ones" (Chambers)
(Breeding may not result in more complex organisms)

I've seen people argue that domestic breeding can not be considered evolution, because domestic breeding:

does not involve natural selection
doesn't direct towards 'fitness'
does not lead to new species
decreases, rather than increases, the size of the gene pool (is this actually true?)
does not (or may not) lead to more complex organisms

I was not able to find whether or not there is a general consensus among experts from relevant fields on whether domestic breeding can be considered evolution. Is there?

EDIT: I've made the list of arguments I've heard against calling it evolution a bit clearer, and also added an extra one.
EDIT 2: Added why the second set of definitions seem to exclude domestic breeding as evolution


texts: What is SDS PAGE gel polymerization time?

texts: I am working on 20% SDS PAGE. I want to know optimum polymerization time for 20% resolving gel and 6% stacking gel. If I increase the time then would it affect the band pattern?


texts: My understanding of chromosomes and the processes related to them is lacking

texts:
I'm sorry for the incredibly simple question, I just can't seem to find any answers elsewhere online.
I am a high school student currently studying for the upcoming AP biology exam, and recently I have realised that I do not quite understand chromosomes. To be specific, I understand what they are (the condensed form of chromatin that one sees when viewing a dividing cell), but my understanding is still lacking when it comes to:

Ploidy, specifically when it changes.
Alleles and how they move/interact during meiosis.
How homologous chromosomes work: When do they occur? Is each chromatid pair identical, or is one chromatid in each pair from each parent?

I made a diagram that details my current understanding, because it can be a bit difficult to describe what I don't understand, but I can try to elaborate more if necessary.

If this is the wrong sort of place to ask this question, some advice on a better place to ask would be greatly appreciated.
Thanks.


texts: Is there a metabolic pathway that generates methanol?

texts: I've been looking for help topics about methanol in metabolism. Specifically, I wish to know what is a common dietary component that generates methanol following metabolism and comment on its toxicity?  I cannot seem to find any relevant data and i'm seeking to know if anyone here has any experience and knowledge of this.


texts:
I have this idea about how we perhaps could decode animal vocabularies that I would like to have some input on.

The idea is to design an experiment/challenge where we could predict roughly what has to be communicated between two individuals of a species in order to succeed with the challenge, for instance two dolphins.

An example could be a colored button that one dolphin has to push to give both dolphins a treat, but where only the other dolphin (the one that can't push it) gets to know which is the correct one. This should encourage them to communicate what to do and specifically what colored button to press. And by doing this kind of experiment several times we could perhaps extract what sounds represent for instance "red". And so on we could build up a basic vocabulary. What do you think about that? =)

The main idea is to in some way encourage two individuals to communicate something that we by design can infer from the outcome of the experiment. If first training one individual in solving a challenge and then letting it observe another individual that has no clue how to solve it, it should encourage it to communicate the solution, if it's sufficient intelligent that is.

Could it be done you think? I wish I had the resources to try this out myself but alas I don't. I'm all out of dolphins. I have asked a few researchers for input but they don't seem to think this is possible since no animal are intelligent enough and have any kind of language in the way we think about it. But personally I don't fully buy that. I still think a few animals would be possible subjects for a test like this, such as dolphins.


texts: Can light function as a neurotransmitter?

texts:
Any animal with an eye has photoreceptors, which are essentially light-sensitive neurons. Green algae have channelrhodopsin, which are ion channels that open and close in response to light. Clearly, the nervous system and its molecular components have evolved to use light effectively.

I'm wondering if light can act as a neurotransmitter in the classical sense; that is, the presynaptic cell releases a photon, which travels across the synaptic cleft and interacts with a receptor, depolarizing the postsynaptic cell. Light can be generated in vivo through chemiluminescence, and as with channelrhodopsin, different proteins can activate in response to different wavelengths or intensities. I suspect this would be much faster than traditional chemical signaling.


texts: When might an inhibitor of bacterial transformation be useful?

texts:
I am part of a project elucidating some structures that are required for bacterial transformation. We have the opportunity to screen inhibitors of the system to stop it from functioning. I am not a microbiologist and have never worked with transformation, and this research process would be time and resource intensive. I am weighing up the pros and cons, however am struggling with how the inhibitors could be practically applied.

How useful would stopping transformation be? My thoughts so far boil down to:

Could it enhance controls by allowing two separate strains to grow on the same plate without any genetic conference?

Could it be applied to stop contamination of genetic information from otherwise insignificant contaminants?

Are there any other problems that transformation is causing in laboratory experiments?


texts:
I am interested in the relationship between blood leptin concentration and fat mass.  It is well known that as fat mass increases, leptin increases.

Have there been studies that look into whether the relationship is linear, or perhaps as fat mass increases, the level of leptin increases at a decreasing rate (e.g. logarithmic relationship) or an increasing rate (exponential) etc.

Furthermore, for two individuals with identical fat mass, is there a high variance of leptin concentration?


texts: Why is offspring of identical twins not identical?

texts: When identical twins marry identical twins, the children of the couples will be full genetic siblings but why are they not genetically identical?


texts: Why does photosynthesis occur even in blue light when the photocentres are activated in red light

texts:
From Engelmann's experiment

  Engelmann used this device to illuminate a strand of Cladophora (not Spirogyra) with light from the visible spectrum, exposing different sections to different wavelengths (or colors of light). He added the oxygen seeking bacteria B. termo to this setup and noted where they accumulated (Note: Four years later, Hauser concluded that B. termo had been mislabeled and was not one, but three species of bacteria of the genus Proteus [2]). Their clumping allowed him to see which regions had the highest concentration of oxygen. He concluded that the most photosynthetically active regions will have the highest concentrations of bacteria. The bacteria accumulated in the regions of red and violet light, showing that these wavelengths of light generated the most photosynthetic activity.

It can be concluded that the photosynthetically active regions of light are present at the blue-violet region and the red region

What I am unable to understand is , if photosystems I and II are activated at light wavelengths of 680nm and 700nm (primarily at the red region of the spectrum) then what type of photosynthesis is happening at the blue region due to which there is oxygen evolution?

My attempt:

The antenna molecules (light harvesting complex) which absorb majorly at this wavelength are transferring energy to the photocentre due to which there is excitation of the photocentre and thus OEC gets activated.

Even if this were true, then should'nt blue light be as effective as red light in helping in generating the quantum yield?


texts: What is working definition for female infertility?

texts:
I've studied infertility and found that its quite complex to define. However, I came to know about a useful working definition of infertility; which was " Failure to achieve pregnancy".
Few days later I've hit upon a idea that proves that definition wrong. As I studied the turner syndrome, in which condition was XO but individual was infertile female. Further I studied that if they are subsequently treated with Gonadotrophin hormones, they have menstrual periods as well. There I found that if a fertilized egg is implanted in their uterus, pregnancy would be achieved. Now how would we call that female infertile?


texts: Which organism built this 2 cm long sandy tube?

texts:
I found this tube and wondered which animal built it.

It is 2 cm long and has an entrance/exit hole on one side. The material seems to be sandy.

I assume it is for breeding purposes.

Before finding the tube, I saw an unfamiliar kind of wasp around (could also be a hornet), with very long black legs. However, I could not find a wasp or hornet that builds such tubes, so it could be unrelated.

Location is Germany.

My questions are: which organism built this structure and should I expect anything crawling out one day? Or is it unfinished, since the entrance isn't closed?


texts: Name this green giant insect hanging on the wall

texts: This Insect was found on the wall of the Party Hall, Where I went to my Girlfriend's birthday party. This insect looks very greeny. I am in India.


texts: Why aren't the twin organs like both the eyes, ears, hands and legs lying both sides of a human body identical?

texts:
Both the eyes are not identical in geometrical shape and size i.e. physical appearances of both the eyes of a person are different from each other. The same difference is observable in both the hands, ears.
I don't know which causes the difference in geometrical shape and size of the twin organs in the human body.
Any explanation will be greatly appreciated.


texts: Are neurons capable of buffering a signal to sync up with other data?

texts:
The brain is the most complex thing that mankind discovered thus far in the universe. Super computers aren't able yet to outperform the human brain (running only on ~25 watt or so) on the domain of general intelligence.
With a computer it is fairly straightforward to capture an image stream and split it into 2 streams. So in a videoclip depth data could be contained by alternating the images from 2 streams from two different angles.
What if an organism would loose sight in 1 eye. And the other eye would be fed with data that contains actually 2 image streams, with these alternating angled images, at an always exact framerate. Would the organism (the brain basically) be able to comprehend the data and experience depth? For that it would kind of need to buffer every other image and put them through simultaneously, mimicking the feed from two eyes basically.
Would this be possible? Is there any research done on a topic similar to the example above? Where data is buffered by a neural network to be send in combination with other data?


texts: How strong of an electric field is dangerous to adult humans?

texts:
Given that "a potential difference is introduced over the membrane, the associated electric field induces a conformational strong in the potassium channel" is required for our muscles to move, how powerful of an electric field is required to cause our muscles (including the heart) to fire irregularly?  How much stronger would it have to be to kill someone?

https://biology.stackexchange.com/a/53330/7973

https://en.wikipedia.org/wiki/Voltage-gated_ion_channel

(No, I'm not an "electrosensitive" afraid of cellphones or high-tension wires.)

Thanks


texts: Why is sedimentation rate significant for a ribsome

texts: When we take a look at biology textbooks (Campbell,  Pearson etc), they will only mention the difference between eukaryotic and prokaryotic ribosome sedimentation rates. Why is sedimentation rate numerically important for ribosomes and not for other organelles like the mitochondria or the nucleus?


texts: How to gauge the clinical significance of specific cell type presence?

texts:
How does one decide whether the presence of certain cell types is clinically important or negligible? Would the presence of certain cells in conjunction with other symptoms be enough, or should it be judged on relative proportions?

I have arrived at a diagnosis for a case study (and I know it is correct) and am just reviewing what I have included and am beginning to question myself. I fear that I am making unnecessary tenuous connections to further support my conclusions.

An example, to put this into context:

A peripheral blood film has all the hallmarks of acute myeloid
leukaemia (AML), however, the film alone is not enough to confirm.
In addition, have spotted definitely one, maybe two, dacrocytes (teardrop cell) on the film, these are not typically associated with AML as far as I am aware.
Dacryocytes are not diagnostically indicative of any specific
condition.
Dacrocytes are however present in several conditions that can
transform to AML.

So, in this scenario, I feel it would be worth mentioning considering the clinical setting but the numbers just seem so insignificant that I am concerned it would appear as grasping, or a bit through the grapevine.

Any guidance in general is appreciated, I'm not looking for an answer to the provided example per se.


texts: Just saw a meme online with this fish on it. Is this a real fish? Can some aquatic expert identify this for us?


texts:
This question asked: What is the evidence it is feasible to reverse ocean acidification by adding large quantities of a base (bicarb soda)?

The result was:

  Danny Harvey of the University of Toronto has already looked into this. His solution is to deposit 4 Gt/yr of limestone into the oceans. To put this in perspective, global coal production in 2013 was nearly double this at 7.823 Gt and it is more than global iron ore production in 2014 of 3.22 Gt.

The respondent then posed the question: What impact would such a huge annual deposition of limestone have of ocean life forms and biodiversity?

My question is: What would be the impact of depositing limestone in the oceans (to reverse acidification) on ocean life forms and biodiversity?


texts: Do orcas react differently to swimmers in orca-like dresses?

texts: Question on animal behaviour. This video shows the trainers of the orcas in swimming pool with them. Why do they use orca-like dresses? Is it just for the show, or do orcas then treat them more peacefully? :)


texts: What is the explanation for the smaller number of tRNA than codons?

texts:
Translation, or decoding, of the four-nucleotide language of DNA and
  mRNA into the 20–amino acid language of proteins requires tRNAs and
  enzymes called aminoacyl-tRNA synthetases. To participate in protein
  synthesis, a tRNA molecule must become chemically linked to a
  particular amino acid via a high-energy bond, forming an
  aminoacyl-tRNA; the anticodon in the tRNA then base-pairs with a codon
  in mRNA so that the activated amino acid can be added to the growing
  polypeptide chain.

  Some 30–40 different tRNAs have been identified in bacterial cells
  and as many as 50–100 in animal and plant cells. Thus the number of
  tRNAs in most cells is more than the number of amino acids used in
  protein synthesis (20) and also differs from the number of amino acid
  codons in the genetic code (61). Consequently, many amino acids have
  more than one tRNA to which they can attach ; in addition, many tRNAs
  can pair with more than one codon.

If perfect Watson-Crick base pairing were demanded between codons and anticodons, cells would have to contain exactly 61 different tRNA species, one for each codon that specifies an amino acid. As noted above, however, many cells contain fewer than 61 tRNAs.

What is the explanation for the smaller number of tRNA than  codons codons?


texts: Is Urea excretion a shared ancestral trait of amphibians and mammals relative to synapomorphic Uric Acid excretion in living reptiles?

texts: Is the ancestral condition of prehistoric amphibians and early amniotes urea excretion? Would it follow then that the lineage leading to living reptiles went on to evolve uric acid excretion as a derived trait? Therefore urea excretion is a shared plesiomorphy of living amphibians and living mammals relative to a synapopmorphy of uric excretion in living reptiles?


texts: Relative concentration of enzyme vs reaction product

texts:
I was reading a paper in which a recombinant protein (His-6 tagged) is expressed in E Coli (BL21 DE3). The yield of the enzyme isolated from the culture is reported as 10-30 mg per L of bacterial culture. (After purification by Ni-affinity Chromatography)

First, is this a reasonable concentration for an enzyme? I thought it was rather high.

Second, when they measure the concentration of the product of the enzymatic reaction that was found to be merely 1-3 mg/Litre of bacterial culture.

Is this typical or unusual for the product concentration to be an order of magnitude smaller than the enzyme concentration? I assumed that since enzymes were in catalytic amounts they ought to be at lower concentrations?

PS. They use SDS-PAGE followed by the Bradford method for determining the protein titres. How accurate is the Bradford method?


texts: How can oxygen production during photosynthesis be measured?

texts:
I'm curious how people measure quantitatively photosynthetic rate in labs.

I've seen many qualitative examples with direct observations of bubbles forming in water due to photosynthetic output of aquatic plants.

The ways I have come up with are:

to measure the CO2 intake.
to measure the O2 output.
to measure the amount of sugar produced.

The 3rd option seems most trivial, but I don't know how to measure the amount of CO2 present in a container. With a reaction? Or with a measuring machine of some sort? What about O2?


texts: What are minerals (other than zinc) that the human body cannot store

texts:
It is known that zinc is an essential mineral that the body cannot store.

What are other minerals, especially metals, that the body cannot store?

(other than water-soluble vitamins such as vitamin B and C)

Sincere thanks.


texts: Why are some vegetables/fruits seasonal?

texts:
How does the mango tree perceive the summer season, so tree starts producing the fruits?

Every tree requires sunlight to grow but what limits the production of fruits to a certain season?

For example: Mango only grows in summer season, whereas banana grows in all seasons.


texts: How did Smith et al 2004 deal with missing HI [Hemagglutination Inhibition assay] values and HI values <10?

texts:
In the scientific paper "Mapping the Antigenic and Genetic Evolution of Influenza Virus's" Supporting Material, Smith et al write about determining antigenic distance Dij. However, I don't understand how one could calculate Dij from HI values of <10. Is it better to remove these data values or to change it to 9?

Also, regarding the missing data, how does one make a comprehensive antigenic map using shape space distance dij? I see that an error function must be minimized, but how does that give dij for all the missing data? Should missing data be ignored for the error function?


texts: Is it better to receive a certain dose of radition gradually or all at once?

texts:
Suppose you had to choose between getting exposed to 1000 mSv gradually over the next 5 years, or all at once exactly 5 years from now.

Which one would be the healthiest option? Is the probability of having developed a disease like cancer after those 5 years the same in both cases?

Phrased differently: Are the effects of multiple doses of radiation entirely probabilistic and/or cumulative?

Thanks in advance!


texts: What is the scientific opinion on plus lens therapy?

texts:
Plus lens therapy is the theory that most myopia is environmentally triggered and that conventional corrective minus lenses increase nearsightedness over time. Thus the hypothesis that applying plus lenses for nearsightedness will invert the environmental pressures and halt or reverse existing myopia.

What is the scientific majority and minority opinion on plus lens therapy?


texts: Consider two linked loci that are 50+ map units apart. I perform a test cross between a female that is heterozygous at both loci to a male that is homozygous recessive. In this case, the phenotypic ratio of the offspring will be 1:1:1:1 suggesting that the loci are independently assorting. Then, I cross a heterozygous male to a homozygous recessive female. In this case I will have just two phenotypes due to the lack of recombination in male drosophila. Do I describe the loci as linked or unlinked in this scenario? Do we consider the loci to be linked for males and unlinked for females?


texts: How would one go about identifying unknown cell cycle checkpoint proteins (i.e., cyclins)?

texts:
No this is not 'homework'. I'm a PhD student, and this was something brought up at the end of a journal club recently, and one of the PIs posed this question and told us to think about it. It sounds simple, but it sort of has me baffled.

Western blot: No. Need a known antigen and so, since we don't know what we're after, this won't work.
Total protein gel: Collect cell lysates from different cell populations that are in different parts of the cell cycle, run it on a gel and observe any cyclic expression. This seems sort of ok but I feel like there are a few problems with it: 1) identifying the cell populations that are in the different cycle stages; 2) other proteins of same/similar size that cannot be differentiated.
Some sort of RNAi, knockdown, etc.: Like the western blot, we don't know what we're dealing with and so can't target anything.
Pulldown assay with mass spec: I don't know a lot about it aside from that it looks at protein-protein interactions. Unsure if it would be appropriate here.

As far as a model, I was thinking either yeast or some immortalized mammalian cell line.


texts: What are the implications of tigers being susceptible to SARS-CoV-2?

texts:
It was recently reported that a handful of tigers and lions tested positive at the Bronx Zoo for SARS-CoV-2 (see here and here). Does this imply that the SARS-CoV-2 strain in humans mutated into a form that can infect these other species? I thought these sorts of mutations required a long time and prolonged contact between the species (which I wouldn't have thought would be present with such large cats).
Alternatively, is it possible that a single strain of the virus is capable of infecting multiple species?


texts:
How does an overdose of sleeping pills kill?
What are the body's reactions to an overdose?
In an article published in ScienceDaily, I read that "Sleeping pills owe half their benefit to the placebo effect".
So what constituents of a sleeping pill, when taken in excess, lead to a negative reaction?


texts:
What is the name of this graph/plot?
What is the name of this graph/plot?


texts: Small flying insects gathering around the pot flowers

texts:
Recently I spotted relatively small flying insects gathering around the pots inside my flat.

There are smaller than fruit flies, probably around 1mm - 2mm long, blackish, and fly somewhat erratically. As far as I can tell the insects are active mostly during the day.

I didn't spot any obvious damage to the plants so far, but I might have miss something.

The location is relatively warm (southern window, above heating sink), and excluding the soil in the pots, rather dry.

Geographical location: Central Europe
Time of observation: Late summer, early autumn.

I'd be grateful if someone could help me identify this species.


texts: Example(s) of reduced rate of mitotic progression?

texts: Most species complete mitosis, and in particular the process of chromosome condensation, rather quickly, in a matter of minutes. Are there any known species that undergo mitoses with substantially reduced kinetics (on the time scale of hours), particularly with respect to the processes of chromosome condensation (prophase through metaphase) or decondensation (anaphase through telophase)?


texts: How to measure the total number of cells in an average human body?

texts: I have got one assignment to calculate the approximate sum total of all cells in the human body. How to tackle this problem? I know that the current statistics is $10^{13}$ cells. I wanted some hints.


texts: How do mushrooms react to being grown in a microgravity environment?

texts:
I'll use Agaricus Bisporus as an example mushroom. If cultured in potato dextrose yeast extract agar, will the resulting growth grow in a normal pattern? Will the sporocarps emerge from the surface (assuming there is one) properly? Will they develop inside the agar, or emerge an an angle?

Will the plant develop at a normal rate, and to normal proportions?


texts: Are the changes required to produce genetically manipulated organisms (GMOS) considered to be mutations

texts: By definition, are mutations required to be natural, or are synthetic lab-induced genetic changes considered mutations too? Furthermore, are genetically manipulated organisms (GMOs) considered forced mutants?


texts: Are there predators evolved to eat puffer fish?

texts:
Puffer fish is known for having a anti-predation defense mechanism of having toxin-exuding spikes.

Are there predators which evolved specifically to prey on puffer fish? (presumably, by evolving immunity to the toxin)?

I know that sharks eat them, but I doubt sharks evolved to be immune specifically to puffer fish toxin, since their evolutionary development preceded puffer fish's.


texts: What kind of fish is this? I don't remember the full name but it started with Tiger

texts: name starts with tiger, forgot the rest, please help


texts: Does RNA serve as the genetic material of some plants and animals along with viruses?

texts:
My teacher mentioned that some plants and animals have RNA as genetic material but did not substantiate his statement  with examples. I'm wondering if it is so?
I have searched the internet but have found no such information.


texts: Coracoid vs. Coronoid - Etymology/Naming Choice?

texts:
The word coracoid (e.g., coracoid process of scapula) literally means "resembling a crow/raven" or "of the form of a crow/raven." In this case, I assume, resembling the hooked characteristic of a corvid's beak.

Etymology: korax ("raven",Greek) + -oid (from Greek -oeidēs meaning "form").

However, the word coronoid (e.g., coronoid process of the ulna or of the mandible) also refers to a hooked projection of bone. Its etymology, however, is more straightforward:

Etymology: korōnē ("hooked", Greek) + -oid (from Greek -oeidēs meaning "form").

My question: Why the distinction?
 - Why is one termed the "coracoid" while the other structures are referred to as "coronoid"?

Since the coracoid process looks no more like an actual corvid's beak than the other structures, it seems that they should have all been referred to as "coranoid".

I get that we've just kept things the way they originally were b/c we like to do that in biology, but what was the original reason for the naming of the  coracoid to break from the trend?


texts: Where can I find the pZ189vector plasmid vector sequence?

texts:
I need this sequence since it was used in this paper https://onlinelibrary.wiley.com/doi/pdf/10.1002/em.1046. They say that the plasmid was prepared as in this paper http://www.jbc.org/content/271/16/9637/F1.expansion.html (see figure below)

However, they do not seem to be reporting the sequence of the pZ189 vector. Does anybody know where can I find this sequence?


texts: Derivation of Michaelis' Equation from Michaelis' Constants

texts:
The enzyme reaction condition, $E + S \leftrightarrow ES \rightarrow E + P$ uses $\kappa_{1}$ (forward reaction), $\kappa_{-1}$ and $\kappa_{2}$ as the rate constants.

E: Enzyme
S: Substrate
P: Product

What is the relationship between $\kappa_{1}$, $\kappa_{-1}$ and $\kappa_{2}$ to yield Michaelis's constant:

$\kappa_{m}$ = ($\kappa_{-1}$ + $\kappa_{2}$) / $\kappa_{2}$ ?

I understand that $\kappa_{m}$ = $S$ at $1/2 \times V_{max}$, however I do not understand the relationship of the rate constants based on the enzyme reaction condition.

This question has been marked as a repeat of the question "How does pH affect Michaelis' constant". I am not asking for any affect with pH, just a proof for the mathematical relationship of the factors shown above.


texts: Open database of whole slide digital pathology images

texts:
I am looking for sequential image sections (stacks) of biological structures (such as liver, kidneys etc.) that I can download and use. Most of the pathology images I have found are either one image or 3-4 sections. I am looking for >50 sections to test some code.

Is there a public repository for this kind of data?


texts: How does a bacterium age without cell division?

texts: If somehow a bacterium, let's say E. coli, is engineered in such a way that it loses the formation of ftsZ ring (or other ways that inhibit cell division), and if other conditions are optimal for bacterial growth, then will the bacterium grow without cell division? If so, how long will it live? And how will it age?


texts: If Evolution Is In Progress, Why Fight Extinction?

texts:
Natural selection is a central tenet of evolution. However, most biologists seem determined to prevent the extinction of the species that have been selected against. Why is this? Preservation of genetic diversity?

I thought evolution was supposed to create diversity not destroy it. What am I missing?


texts: Do all species have asymmetric female meiosis?

texts:
In all the examples I can think of, (mostly vertebrate), female meiosis, or oogenesis, only haploid gamete is produced while the other cell divisions result in polar bodies. While male meiosis results in 4 haploid gametes. This difference follows the fundamental definition of female and males being defined as resources committed into reproductive cells.

I want to know if this asymmetrical gamete production is truly universal across all organisms. Are all meiosis in plants or unicellular organisms unequal between male and female?


texts: Why did humans evolve the ability to feel such a high level of heat pain?

texts: It's probably because our ancestors were frequently around 300°C metal which badly damages flesh in a fraction of a second because they made fires to cook. I don't see why that would cause natural selection to make that pain so extreme instead of only slight. It's so rare for somebody to die from getting a nasty burn from touching such a hot metal. Is it because those who didn't feel heat pain were frequently holding very hot metal objects and although each one touching made them only a tiny bit less likely to survive, the damage added up and eventually they would have held such hot metal objects so many times that they had a very high probability of dying?


texts:
Centimorgan's aren't physical distances. The analogy that I could come up with is if you had an array with 10 items,

A = [a, b, c, d, e, f ,g ,h ,i ,j, k]

The distance of a in the array is closer to b than k, ie A[0] is closer to A[1] than A[10] so that the centimorgan of A[0] and A[1] is less than A[0] and A[10]?


texts: What if there are no bacteria such as Streptococcus mutans

texts:
If someone removed all bacteria such Streptococcus mutans in her mouth by starving long time, or by some chemical method, would she never have such bacteria?

In my thought, because S.mutans only spread out through human teeth, and if there are some in the air, white blood cell might kill all from the air completely because they are very little.

Is this foolish hypothesis of mine possible?

Thanks for your answer in advance.


texts: How do we know that selective agonists are indeed selective?

texts: Suppose we know that compound X is a selective agonist of receptor Y, meaning that it binds only this receptor Y and no other. But how do we know this that it doesn't bind some another receptor? I suppose that screening for the binding strength of a given ligand to all known receptors would be very tedious and not feasible.


texts: You can judge my habits later, but sometimes I stick my finger in my ear and smell my finger. When doing this, I get a pleasant smell for some reason. I haven't use hair lotion for a long time cause I have like no hair. I suspect it has to do with my headphones since I wear them often, but i have them for more than a year.


texts: Can living cells be imaged with electron microscopy?

texts:
According to this article from October 2009, http://news.mit.edu/2009/electron-microscope

  "Electron microscopes are the most powerful type of microscope,
  capable of distinguishing even individual atoms. However, these
  microscopes cannot be used to image living cells because the electrons
  destroy the samples."

  "Now, MIT assistant professor Mehmet Fatih Yanik and his student,
  William Putnam, propose a new scheme that can overcome this limitation
  by using a quantum mechanical measurement technique that allows
  electrons to sense objects remotely. Damage would be avoided because
  the electrons would never actually hit the imaged objects."

Is it possible yet to image living cells with an electron microscope? If not, has there been any advance in this direction?


texts: Slicing cell cultures frozen in vitrified ice with a laser for CryoEM

texts: Could a cell culture frozen in vitrified ice for CryoEM be effectively sliced into thin planes and resolved images produced? I was thinking if this could be done to get images from inside a cell.


texts: Average Nucleus size of human skeletal muscle cell

texts:
I’ve been struggling the last couple of days to find reliable data on the average nucleus size of a human skeletal muscle cell. If I deduce it from pictures it should be in the range of 20 micrometers long and 3 micrometers in diameter but I need reliable data and a proper source.

Could anyone help me with this?


texts: Why do veins undergo vasoconstriction during physical activity?

texts: How would this help increase blood circulation?


texts:
For some time we've been finding these little fellows in our apartment:

They seem harmless enough, but finding them is a bit... annoying. I found the fellow above in the bathtub, and it's not uncommon to find more than one.

Unfortunately, some started to appear near the kitchen sink as well. Or outside of the bathroom on the floor (at least that's where we noticed them).

I think this thing prefers darkness over light, and seems to be drawn towards wet places or just water. These critters are also surprisingly fast.

What is it? Should we be concerned about a pest problem, or is this just a minor, unwelcome guest?

PS. We live in Poland.


texts: How do fish persist in the upper parts of mountainous rivers with waterfalls?

texts:
I was recently traveling in a remote mountain region and hiking alongside a very small river.
What caught my attention was the fish in the small ponds under the waterfalls.
These ponds were just a couple of square meters in size and each one housed between 5 and 10 fish.
The course (do you mean flow?) of the river combined with the waterfalls mean it was basically out of question that they could swim / jump upstream.
In such small mountainous rivers, how do fish remain in the upper parts over the course of hundreds of years.
I mean the size of the ponds and the amount of fish did not look to me like it could be sustainable for a population. And there should be the occasional one going down.
Are there examples or situations where the upstream population becomes extinct?


texts: Pyruvate seems to pass easily through the outer membrane of the mitochondrion but has difficulty entering the inner membrane (and gets in by H+ symport). I have two questions: (1) what property of pyruvate disallows it from passing through the inner membrane? Is it its charge? and (2) what structural differences are there between the outer and inner membranes of the mitochondrion that create their disparate permeabilities to pyruvate?


texts:
I have this tiny tree in my garden in Cancun, Q.Roo Mexico.

(More photos available here.)

The little tree started to grow in a planter. I did not pay any attention to it until it grew to 10 cm. It does grow like any bigger tree, starting with one curving branch with regular leaves. I buy unsterilized soil from locals and always get something growing without planting.
It is a phyllanthus plant, but that is all we know so far.
By now I have 20 little ones and one big one, which is a year and a half old.

It certainly is not a phyllanthus Niuri which is an incredible medicinal plant, but with way less "tree attitude" than this one.

This lovely bonsai tree could be unknown to the world, hidden in the deep vegetation of the Yucatan peninsula, one of the world's regions with the highest tree variety.

Can you identify this tree for me?


texts: Scale up of Bacterial growth from 250mL to 1-5L?

texts:
I am currently growing up a specific strain of E.Coli with a knockout in 40mL of growth medium (LB) in a 250mL shaker flask... My ultimate goal is to scale up this process to a 1-5L large scale setup for the lab. But for now I'd like to quantitatively characterize this 250mL scale using Monod Kinetics so that the mathematical model can be used to build the aforementioned bio-reactor.

Currently I am making two growth curves of the E.Coli in the current 250mL flask. One is OD vs. time and the other g.Dry mass vs. time. The idea of doing so is to ascertain the $\mu_g^{max}$ (maximum specific growth rate). However, I am stuck as to how to find the saturation constant (Ks). I am also stuck on how to measure the sugar concentration ([S]) at each time-point that I would measure the OD. The idea behind these two variables is to use the equation(s):

$D = \mu_g^{max} . \frac{[S]}{Ks + [S]}\\
D^{\ max} = \mu_g^{max} . \frac{[S^{\ max}]}{Ks + [S^{\ max}]}$

Am I looking for the right variables and/or using the right equations?

Thanks again for your help!


texts: If Tumors have lots of mutations in them how is it the immune system can't detect them?

texts: If a cancerous tumor has a lot of mutations in them why can't the immune system detect them? If a person has cancer could this somehow alter the person's immune system so it doesn't function effectively to detect greatly mutated cells? Does the fact that a tumor is 'made' of 'mutated' non-foreign human cells help it to be undetectable?


texts:
My textbook says, secretin secretion is triggered by the presence of acidic chyme in intestine.

But why is secretin sensitive to acidic environment? I checked the wikipedia page of secretin and found no related information.
Is there some mechanism for secretin to secrete in presence of acidic chyme?


texts:
Please help identify this insect - genus, species and anything interesting about it.

Note, this is posted separately due to comments in this other thread.

I'm


texts: What happens in a nerve cell when a thought is generated?

texts: I know basic nerve physiology of impulse conduction and transmission, but I don't know what actually happens in a nerve cell when a thought is generated. When a external stimulus (like tactile stimulation, injury causing tissue damage) leads to stimulation of respective Na+Channels and action potential is generated. But what is the stimulus in the neurons of the Central Nervous System when we think about something? What exactly is the stimulus that cause the neuron to generate action potential and then following it, it is transmitted to different circuits and then we react accordingly?


texts: By What Mechanism Does Heat Cause Muscle Relaxation?

texts: Heat is commonly used "loosen" muscles, but what exactly is happening to relax the muscle? It wouldn't make sense that increased blood flow alone would relax muscle.


texts: Does the bending of a tree's trunk in the wind stimulate and strengthen root growth?

texts:
Recently Southern California experienced extreme wind velocities and afterwards the news reported over 300 trees had fallen in San Diego County. I had either heard or read somewhere that the action of the wind and bending of a tree assists to strengthen the roots ( I suppose as long as the wind is not strong enough to pull the tree out of the ground). And so that brings me to the point of my question.

Does some kind of mechanism exist within the tree that connects mechanical bending of the trunk with increased rate of root growth? I can imagine that bending might stimulate fluid movement through the phloem & xylem, and perhaps this might be the mechanism. Or does the bending cause a release of some type of growth hormone? Or perhaps the mechanism is epigenetic?

I suppose that if such a mechanism were to exist it would provide one means of evolutionary weeding; removing the weaker part of the gene pool. Perhaps that's what happened in San Diego this last week.


texts: Clarification for the anatomical terminology of the cerebellum

texts:
I've been trying to find descriptions for some of the fissures found on the inferior surface of the cerebellum, and so far the only source I've been able to find that provides an adequate description is Gray's anatomy (1918, 20th edition):

The prepyramidal fissure crosses the vermis between the uvula in front and the pyramid behind, then curves forward between the tonsil and the biventral lobe, to join the postnodular fissure.
The postpyramidal fissure passes across the vermis between the pyramid and the tuber vermis, and, in the hemispheres, courses behind the tonsil and biventral lobules, and then along the lateral border of the
biventral lobule to the postnodular sulcus; in the hemisphere it forms the anterior boundary of the inferior semilunar lobule.

So, that would make these fissures the following ones:

(the blue one being the postpyramidal fissure, and the red one being the prepyramidal fissure)
However, I checked a few atlases:

(here, 2 and 2' are the postpyramidal fissure and 4 is the prepyramidal fissure)
And on radiologykey, the descriptions it gives for these fissures is the following:

The postpyramidal (secondary) fissure separates the pyramis/biventral lobule above from the uvula/tonsils below
the prepyramidal fissure separates the tuber above from the pyramis below.

It seems like Gray's anatomy has the names swapped or something, is that the case? If so, that means I can still use these descriptions but just swap the names.
And is the secondary fissure the same as the retrotonsilar fissure/postpyramidal fissure?


texts:
How do butterflies defend themselves from other creatures when they don't have the ability to sting or some other offensive/defensive mechanism?

  Butterflies are part of the class of Insects in the order Lepidoptera. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight.


texts: Where do the 31 spinal nerves start/meet?

texts:
Which part of the brain is the first place (from top to bottom) where all 31 pairs of spinal nerves (on each side) meet? Or if they all start at one place - where is that?

Nominally, the beginning of the spinal cord is the medulla oblongata, but perhaps the spinal nerves or some sort of "root" of every nerve start at the Thalamus?


texts: How are large snails able to climb trees?

texts:
In answers to What kind of hot pink eggs are these? and the linked duplicate I found out that snails that live in the water will climb up a smooth stick or branch to deposit their eggs. Today I saw several large (8 to 10 cm) snails climbing trees both a relatively smooth one and one with considerably rough bark.

How do these large and heavy snails manage to adhere safely to the sides of trees and climb so high? Is it adhesion? Is suction involved?

click images for full size view

above: June, northern Taiwan lowlands in a damp area. They look similar to the species discussed in answers to What are these four large snails doing? below: from What kind of hot pink eggs are these?


texts: How long does it take for DNA to degrade

texts: Can i still use 3-4 years old bacterial DNA template for my PCR? They were kept in -20 all this while. Will the DNA degrade?


texts: Why DNA gyrase inhibitor, such as Nalidixic acid and Norfloxacin, do not stop gyrase from cutting DNA helix but only prevent them from decatenation replicating DNA?


texts: Transgenic Plant-Gene source for introduction into host organism

texts:
Let's say the plant-gene itself is known, i.e. the exact neucleotide sequence is available in a gene bank (originally sequenced from a tree sample extracted RNA). Previous work has already successfuly inserted & expressed the gene in a host bacterium, say, E Coli.

My question is: Does subsequent work on inserting the gene into other host organisms also have to start from tree samples as source of the RNA & hence DNA?

Or is there a more direct route to convert a Neucleotide sequence from a gene database into actual DNA that can be inserted into hosts?

e.g. Are there machines that can take a sequence & synthesize the correct DNA molecules? Or not yet?


texts: What is this small tissue structure found in kidney?

texts: It's covered with white adipose tissue and it is smooth with reddish brown colour. HE dyed with dimensions 3 cm long and 1 cm wide. I'm guessing that this is a rare thing because I already checked pubmed etc. On the right is a closer picture of the tissue.


texts: What would the ploidy of a multinucleate cell be?

texts: If we have a haploid organism, and it undergoes karyokinesis without cytokinesis, would the organism be considered haploid or diploid?


texts: Can adding Trypsin to mammalian cells affect the expression of or hydrolyze cell surface receptors?


texts:
In the animal kingdom there is a striking variety of pupil shapes, with great variety among relatively close relatives. Cats have vertical slits. Siberian tigers have round pupils. Cuttlefish have a W shape. Goats have what I would call a horizontal bar. Many foxes have vertical slits, many dogs have round ones.

I just started paying attention to it and I was looking at some good pictures of both Japanese and European squirrels. I sometimes feel that I see a round irregularity at the centre, but can never be sure.