texts: How many kg of seed can one expect from 230 kg of cotton fiber?

texts:
So I'm working with data from recent cotton harvest from a seed company. They're more interested in cotton seed than the fiber itself. I'm trying to come up with seed yield numbers for an array of cultivars but the data I was given came in kg of harvested fiber. Excluding any changes between cultivars due to genetics,

Does anyone have an idea of how many kg of cotton seed I can get from a given yield of cotton fiber?

Kind regards,


texts: Adaptive Optics in Microscopy: what are the fastest processes in specimen causing optical aberrations?

texts:
Some companies e.g. the one of Nobel prize winner Stefan Hell (Abberior) are offering Adaptive Optics enhancements for microscopes for allowing deeper focus in locally changing optically refractive specimens. The underlying principle is quite well explained under the keywords 'astronomical seeing' or 'adaptive optics'.
I am (not a biologist at all and) wondering how fast these local patterns of different refraction can change in any microscopy task?


texts: Which part of the reflex arc takes the longest time?

texts:
The reflex arc is composed of 5 parts:

sensory receptors, afferent neuron(s), synapses within the central integrating station, efferent neuron(s) and the effector (includes transmission across the neuro-muscular junction and contractile mechanism - Assuming this is a myotatic reflex).

Which part takes the longest time & why?


texts: Is wiping with RNAse Zap enough to destroy RNAse activity?

texts:
From the RNAseZap MSDS, it is an SDS at some unknown concentration, maybe with some NaOH?

Some other links suggest there is some NaOH as well.

The Ambion site states that RNAseZap destroys RNAse activity on contact, but they also instruct to rinse with water twice after wiping RNAseZap on the surface being cleaned.

So, does RNAseZap actually destroy RNAse activity, or is it simply a "good detergent" to pick them up and rinse them away?

Thanks!
Carmen


texts: When there is incomplete dominance of one allele, is one allele still considered recessive?

texts:
When you have incomplete dominance between two alleles of a gene (say, on two different tail lengths blending into an intermediate tail length or two rose colours blending together), can you still call an allele recessive or dominant? If so, how would you tell which to call "dominant" and which to call "recessive"? Do you compare protein expression or measure the difference between the phenotypes of the two homozygous variants or something?
This is purely a terminology question -- I'm aware that the distinction might be a bit meaningless in practice. The closest I could find to an answer is this question, though I'm unsure whether they're measuring tail length to determine the difference between codominance and partial dominance or what.


texts: Does drinking dry water have same effect as drinking regular water?

texts:
Dry water consists of water droplets that have been coated with silica nanoparticles, which prevents the droplets from forming a liquid.

If a human swallows dry water, does it have the same effect as regular water? Or do the particles go through the digestive system without releasing water inside? Is it dangerous to "drink" dry water?


texts: Do non-migratory canada geese still exhibit migration behaviors?

texts:
I have noticed that many of the geese in my region (NE US) remain overwinter. I also see many of what I guess (but am not sure) may be the same geese flying in migration patterns. One thing that makes me think that non migrating geese do this, is that I observe group formations flying in all directions, not just southwards in the fall.

Does anyone know whether the resident geese still like to fly in migration patterns, or is it always the migrating geese that you see doing this?


texts: If life is discovered on another planet, will it likely be classified using the current domain/kingdom/phylum system?

texts: This may be a stupid question showing my lack of understanding of taxonomy, but I was wondering if the current classification system we use contains broad enough categories to include new life forms, if they are discovered on other planets?  Would this depend on whether or not the new organisms could be shown to be evolutionarily related (eg have DNA), or are the highest levels of organization independent of relatedness and more dependent on physical similarity?


texts: Why do toenails grow much slower than fingernails?

texts:
As the title suggests, I've noticed that my fingernail grow much faster than my toenails. For instance, I usually trim my fingernails every two week or so, but for toenails the number would be about 6 to 8 weeks.
A bit of research revealed this wikipedia article:

In mammals, the length and growth rate of nails is related to the length of the terminal phalanges (outermost finger bones). Thus, in humans, the nail of the index finger grows faster than that of the little finger; and fingernails grow up to four times faster than toenails. [12]
In humans, nails grow at an average rate of 3 mm (0.12 in) a month.[13] Fingernails require three to six months to regrow completely, and toenails require 12 to 18 months. Actual growth rate is dependent upon age, sex, season, exercise level, diet, and hereditary factors. Nails grow faster in the summer than in any other season.[14]

But correlation does not imply causation, so why should the growth rate of nails depend on the  length of the terminal phalanges? Then why do babies grow nail much faster? I wasn't satisfied by its answer, so I looked a bit more where I found this other article. They had two possible candidates:

because hands are physically closer to the heart than are feet, fingers get better blood circulation and consequently better access to oxygen and nutrients.

Fingernails experience almost constant trauma through tapping, typing, bumping, and other seemingly insignificant actions. These persistent minor traumas stimulate fingernail growth. Toes, on the other hand, are not exposed to nearly as much trauma as they are usually bundled up safely inside socks and shoes. Similarly, fingernails on a person's right hand grow faster in right-handed people than on their left hand and vice-versa.

However they don't give actual experimental results. So my question is which of the above is the real cause of this difference in the growth rate of nails; or simply why toenails grow much slower than fingernails?

P.S. The season dependence and the lefthand-righthand asymmetry were news to me; it would be really nice if the answer explains them as well.


texts: Why do, humans, like many birds,tend to stand on one leg (hut without lifting the other leg)?

texts:
I know, by observing people and from my own experience (you can try it yourself while standing, but not too consciously and in a loose way) that they, while standing, tend to do this on one leg. Just observe yourself and other people. Many birds do this as well. Like the stork:

The reason for this is to reduce heat loss:

Why do some birds stand around on one leg? A. One widespread theory among bird experts involves heat conservation. Herons, hawks, geese, ducks, and gulls — birds both short-legged and long-legged — are on the Audubon Society list of those that tuck up one leg under their feathers and balance on the other.

The question remains: why do people too tend to do this? We don't pull up our entire leg though. Many times I've seen people standing on one leg, their other leg crossed over the other.

Leaning on one leg
Leaning more on one leg while standing, sometimes referred to as “hanging on one hip”, can feel comfortable, especially if you've been standing for a while. Instead of using your buttocks and core muscles to keep you upright, you place excessive pressure on one side of your lower back and hip. Mar 26, 2016


texts:
Are there any good books, that shows some advanced models in genetics particularly?
The problem is i don't see any good math model in genetics interactions exept combinatorics. I'd like to know what else math structures and rules are there in genetics.
I'd like create strong math backbone for better understanding genetics, but i can't find any advanced reliable sources for that. Are there any books that could help me?

Thanks a lot.


texts: Does melatonin change the appearance of humans?

texts:
Melatonin (not to be confused with melanin) was sold as a wonder drug during the 90s. I remember images of mice, which supposedly got a more beautiful fur. I would like to know whether the effect is true and whether it also has an effect on humans skin (or appearance in general).

Obviously, googling about melatonin generates a lot of suspicious results.


texts: How does regurgitated food go to the 3rd stomach chamber instead of going to the 1st?

texts:
Ruminants are known for their regurgitation of food; the food goes through the 1st and 2nd stomach chambers, then returns to the oral cavity in cuds. The cuds then come back into the stomach, but this time they go through the 3rd and 4th chambers, instead of going to the 1st and 2nd again.

How is it ensured that the regurgitated food doesn't go through the 1st and 2nd chamber by a mistake?


texts:
Is this a fossilized backbone? If so then from what?
This "bone" is approximately four inches (10 cm) wide by two inches (5 cm) deep and two inches (5 cm) tall. The texture is rock-like. If it resembles any bone familiar to anyone let me know or take a guess and I'll look into it. I found it in North central Texas in the ground by a massive fruitless mulberry tree on the top of a hill. It weighs about what a 2x2x4 inch chunk of average run of the mill stone would weigh.


texts: Can I elute my GFP-tagged protein off anti-GFP antibody using a peptide?

texts: I would like to perform a modified co-immunoprecipitation assay using a GFP-tagged protein.  We are going to bind the tagged protein to anti-GFP antibody then bind that to protein A/G beads, however we want to be able to selectively elute the tagged protein off the beads.  I know that you can elute a FLAG tagged protein off of M2 anti-FLAG antibody by adding excess FLAG, so can I use the same approach with my GFP tag?  If so, does anyone know a commercially available GFP monoclonal antibody who's epitope has been mapped so I can use excess epitope to elute my protein?  Or possibly a source of recombinant GFP?


texts: Help explain multi alleles in terms of actual genetic code

texts:
I understand that someones genetic makeup at an allele is usually denoted as (AA,Aa,aa).

That means that instead of an A-T pair you get a C-G pair on none, 1 or 2 copies.

Now, what exactly happens when you have a tri-allele (as in blood type). Are they looking at two base positions? Or is it instead of an A -> C mutation, you get something weirder like an A->G mutation (and thus you need to account for directionality) etc?

Thanks!


texts:
Bitter gourd, cucumber, etc. are bitter to taste. Which chemical causes bitterness in them?

I found these when I searched online: this says that it is because of calcium, while this and this talk about physical effects.


texts: Can a cleaved plasmid "close" without exact matching "sticky ends"?

texts:
Say if you have a multiple restriction site and use two restriction enzymes on it to cleave a plasmid, can it recombine with ligase?

My concern is that without the small sequence of nucleotides that were in between the two restriction sites, the two ends of the plasmid won't stick and anneal. Would it work if the two sticky ends are almost the same in sequence – two bp off instead of all five?


texts:
I generated a series of local BLAST databases using makeblastdb of metagenomic data and am searching for the presence of a particular gene. While I can do the normal BLAST analysis looking at e-values, % identity, etc. I haven't been able to figure out how to determine how many times a given sequence exists in the database.

So: given a BLAST database of metagenomic data where a particular gene may exist multiple times, how do I determine the copy number of a given BLAST hit?

Thanks in advance.


texts: water stress expression markers in arabidopsis thaliana

texts: So far I found papers that show studies using RNA arrays on whom they categorized water stress gene markers in root. Water stresses were reproduced by different protocols (manitol...) but always on several week old plants. Does anyone know any study carried on young (6 days more or less) arabidopsis thaliana plants?


texts:
There are bacteria that can enter body cells as parasites.

Could it be that some of these are benign, such that the guest will not kill the host cell it lives in (especially in human)?


texts:
I am looking for a family tree for plants, particularly veg / herbs / fruit.

Something similar to:

If it could be slightly less technical than all the Latin names too :). The aim is to easily find out what plants are related such as Cabbage, Broccoli, sprouts, Cauliflower (all Brassicaceae). Currently having to look them all up on Wikipedia which is quite painful.

Another example, but a plant version.


texts: Why are diabetic people often overweight?

texts:
I was looking at diabetes the other day, and I noticed something strange. Lower amounts of lipase are a symptom of diabetes, as is overweightness. However, since lipase is the enzyme that breaks down fats, shouldn't a lack of it mean that less of it enters your blood stream and is simply excreted instead? In that case, how come diabetic people are often overweight?

This question has been bugging me for ages, does anyone know why?


texts: Pen and paper game to explain the theory of evolution

texts:
Sometimes when explaining the theory of evolution one sees a glazed-over look on the persons face. To this person the theory seems completely incomprehensible no matter which avenue one takes to explain it. This leads me to think that a game might be a fun alternative. In the process of playing, I suspect that the player might pick up a stronger intuition of how and why it works which would eventually lead to understanding the basics as a whole.

It is easy enough to dream up any number of problems that can be presented as a genetic algorithm with pen and paper, the challenge however is to make it easy to understand and fun to play.
Does anyone know of such a game or able to construct such a game?


texts: Difference between inbreeding and interbreeding

texts:
Is inbreeding the same as interbreeding?

On this site interbreeding is defined as (http://www.thefreedictionary.com/interbreeding):

  To breed with another kind or species; hybridize.
  To breed within a narrow range or with closely related types or individuals; inbreed.

But I am sure that interbreeding is not the same as inbreeding. Inbreeding would be between genetically related members of a species and interbreeding would be between genetically un-related members of the same or different species.

after looking at wikepedia pages for both terms as well as searching the english oxford dictionar I am certain they are different


texts:
Habitat:  Men's room at a rest stop in Syracuse, New York.

Size: ~1 cm

Based on my limited searching ability, I think it's a type of "drain fly" (Psychodomorpha): https://en.wikipedia.org/wiki/Psychodomorpha

Hard to get a better picture without a macro lens, but is anyone able to speciate this fuzzy urinal-fly?


texts: What happens if someone with mutations to alcohol dehydrogenase (ADH) drinks alcohol?

texts:
ethanol then doesn't get converted to acetaldehyde.

in fact, could someone KO'ed for ADH be resistant to methanol poisoning?


texts: Weinman AIF and High temporal resolution AIF difference

texts:
I'm dealing with MRI DCE maps. Actually I need to find such parameters as the transfer constant $K^{trans}$ and rate constant $k^{ep}$ according to the two-compartment model.
Mathematically, this dynamic system can be described by the following equation:
$$C_t(t)=DK^{trans} \sum\limits_{i=1}^2 a_i [exp(-k^{ep}t) - exp(-m_it)]/[m_i-k_{ep}]$$
Now if I have contrast agent concentration $C_t(t)$ time series from experiment I can extract transfer constant $K^{trans}$, and rate constant $k^{ep}$ by least square fitting. The only problem is that I need to know $a_i$ and $m_i$ constants. For this purpose I use the next formula for blood plasma concentration: $$c_p(t)=D \sum\limits_{i=1}^2 a_i exp(-m_it)$$
However I can't find the relation between the blood plasma concentration: $c_p(t)$ and $c_t(t)$. In the next article:
 Geoff J.M. Parker et. al. "Experimentally-Derived Functional Form for a Population-Averaged High-Temporal-Resolution Arterial Input Function for Dynamic Contrast-Enhanced MRI"
I have found that biexponential function $c_p(t)$ is used to describe AIF (arterial input function). It's presented on plot as Weinmann AIF.

QUESTIONS:

1) How Weinman AIF and High temporal resolution AIF can describe the same processes, actually from mathematical point of view it's two completely different functions?

2) Do I really can find $a_i$ and $m_i$ parameters by fitting AIF curve with $C_p(t)$ function?

P.S. I'm just a programmer so I completely unaware in the field of biology and any help is appreciated.


texts: will an earthworm survive after covering its skin with a wet cloth

texts: I am very curious about this question. I got this doubt when I was studying anatomy and physiology of the earthworm Lampito mauritii. It breathes through its skin (cutaneous respiration) and if we cover its body with a wet cloth and all the necessary external openings are left uncovered (such as nephridia and other genital pores) then will the earthworm survive?


texts: Getting read size less then specified in parameter file Flux Simulation

texts:
I have tried to use flux simulation tool to generate simulated RNA-seq data.

I gave the following parameter file to flux-simulation shell script

## File locations

REF_FILE_NAME   cElegansAnnotation.gtf
GEN_DIR         chromFa

## Library preparation
# Expression
NB_MOLECULES    5000000
TSS_MEAN    50
POLYA_SCALE     100
POLYA_SHAPE     1.5

# Fragmentation
FRAG_SUBSTRATE  RNA
FRAG_METHOD UR
FRAG_UR_ETA     350

# Reverse Transcription
RTRANSCRIPTION  YES
RT_MOTIF    default

# Amplification
PCR_DISTRIBUTION default
GC_MEAN      NaN
PCR_PROBABILITY  0.05

# Size Filtering
FILTERING   NO

## Sequencing
READ_NUMBER 1000000
READ_LENGTH 100
PAIRED_END  YES

# create a fastq file
FASTA           YES

According to this parameter, flux-simulation should have given reads with length 100. However when I look at the output, I have seen that reads with less then length of 100 are also included in my  fasta file:

>chrI:47472-49416W:Y48G1C.12:3:651:351:594:A/1
CGTCGAAATTAGTGATATTTTTATCGGGAATCGGTCCGTGTGGTTCTCCGGTGAATATTCGATTCGTTGTGGAGACACGAGATCGCTGGGGTCCAAGGAC
>chrI:47472-49416W:Y48G1C.12:4:651:394:467:S/1
TACGCGACAAAAATGGGAAACCGAATCGCGTTTTTTGGCTTCAAGTACAAGTTATTCAGAATCATCAAAATGGG
>chrI:47472-49416W:Y48G1C.12:4:651:394:467:A/2
CCCATTTTGATGATTCTGAATAACTTGTACTTGAAGCCAAAAAACGCGATTCGGTTTCCCATTTTTGTCGCGTA
>chrI:47472-49416W:Y48G1C.12:5:651:126:142:S/2
AGTTGTAAAAGCGGATT

So, is there anyone how could I fix it?


texts: Identify the fluff that I have found in tea

texts:
I have just opened a new pack of a black Pu'er tea that I've bought at the local store selling it by weight, and found a piece of fluff in there. To me it looks much like some kind of a bird fluff. It might also actually be a plant fluff, but somehow I doubt it. Probably it was white originally, but being so long in contact with the tea made it a bit browner.

Of course it spoiled all the impression of the tea. Now I wonder if I should drink it, or even keep buying at the same store. The worst thing is that their supplier is one of the major suppliers of Chinese tea in our country, and this is not the first time I find something hairy in it. The last time it was a human hair.

The questions:

Please help identify what it is (I don't mean a particular species of whatever it is, but at least what is it? Bird fluff, plant fluff, synthetic fluff?)
Would you still drink your tea if you'd find such things in it? Like, should it be safe, or is there any risk in contracting some terrible infection or a virus in case if it comes from a bird?

Here are some photos that I've made:

It also very much looks like this picture I've found in the internet, but failed to find a proper description of what is it actually (the most bold one was that its a swan fluff, but I can't imagine how a swan would come in contact with the tea):


texts: I have seen this question where the author is asking why people take drugs for fever. So my question is: Is fever is a disease or not?


texts:
I am not a biology student, just a curious person. To be specific, I'm talking about female humans. I know that it might apply to other mammals.
What controls the size of breasts?
I have heard about progesterone hormone.

Is it just progesterone?

Are there any other factors?

I have seen a movie in which couple talks about breast size increases after sex. Is it true?

Can somebody give more info on this?


texts: How does the frequency of a visual stimulus affect the steady-state visually evoked potential?

texts:
I want to design a project for EEG signal processing. In my research I found the concept of SSVEP. SSVEPs represent the electrical activity of the brain as measured via EEG, and are evoked by visual stimuli with low frequency applied to the eye.

My question is whether it is known how the electric activity of brain will change? And a second thing, does it mean that each frequency applied to the eye has a fixed reaction for the brain?


texts: What type of photosynthesis is performed by phytoplankton?

texts:
I am not a biologist, but I know there exist three variants of photosynthesis, namely C3, C4 and CAM.

I would like to know what type is used by the ocean's phytoplankton? It might also be that different photosynthetic mechanisms are used by the bacteria vs. algae. I have searched the web, but the information I find is too broad.


texts: Can the human body create glucose out of fat?

texts: I read conflicting views about whether or not the human body can create glucose out of fat. Can it?


texts: Can you identify the bird in this photo?

texts: I spotted this bird in Bangalore, atop a building on a September morning.


texts:
You can easily find a lot of pictures of the SARS-CoV-2 virus. But although it should be trivial for an electron microscope to measure the size, I am not able to find accurate size information.

What is the size (diameter) of the SARS-CoV-2 virus?
(Why does some virus particles seem to have a different size?)


texts: Is identifying the genus of a fungus (mushroom specifically) enough?

texts:
Does the genus of a mushroom have enough information about it, without the species?

Let's say I wanted to identify a mushroom (when picking) to see if I can safely pick and later eat it. Let's say I successfully identified the mushroom's genus (using an identification key guide book such as this one). Is this enough to determine whether or not the mushroom is edible? Is it enough to determine other general information about it? Furthermore, is it enough to determine whether it is good-to-eat (as in not bitter)? For example, I know that some edible mushrooms have other mushrooms very similar to them that are not edible or that are bitter and difficult to cook.

In other words, are there any genuses of mushrooms that generally are recognized as edible but in reality contain both edible and inedible species of mushrooms in them?


texts: Where do the protons in the mitochondrial intermembrane space originally come from?

texts:
I'm currently reviewing this concept in cellular respiration. The book which I'm using is Reece, Minorsky, Campbell's Biology and while it does a good job at explaining the process involved in the electron chain transport. I think it lacks of clearing out my doubts concerning initial protons.

Let me explain, the part where I'm stuck at is, where do originally the protons in the mitochondrial intermembrane space come from?. I understand that there is a proton gradient and the translocation of this protons in the proton pump is key during the electron shuttle process but, how did those initial protons come?. In other words, during the formation of the mitochondria in the cell, have they always been there? or are they part of some bigger molecule and that those protons are detached from them so that there is an initial gradient that triggers the process for the first time?. In other words, how does that initial spark or kick off begins?.

In most animations I've found, the explanations take for granted that the protons are freely moving in the intermembrane space such as here and also here but what do those videos lack is the explanation of how (as mentioned above) do those protons got there in the first place.

I'd like somebody could help me to clear out this doubt. I feel that as an addition to the answer, I'd like to know how does the mitochondria forms in the cell?. Since I believe there might be steps involved, I'd appreciate that the answer could explain those steps so I could easily understand, because as mentioned. I'm still confused on that part as well.


texts: What makes boric acid so toxic to roaches and not so much to any other insect?

texts: When I look up boric acid on the net there are various ads for it to kill roaches but no explanation of why it is effective on roaches. I am in East TX , roach central. When my house was built I put pounds of boric acid in between the studs before drywall went up . For 25 years  I don't think I saw a dozen roaches in the house. But starting this spring ,I have killed a few roaches every night . As if they became immune to the boric acid ( as much as I put in ,it could not be gone). We have pets so I am reluctant to use insecticide in the house.


texts: I have been reading about drug-gene interactions and pharmacogenetic tests. I haven't been able to find many resources that define the process of testing for possible drug-gene interactions without performing trial and error method. For example, drug-drug interactions can be predicted by using several parameters as noted here. Are there any parameters similar to the ones described in given paper for predicting drug-gene interactions if drug characteristics and genetic data is available? Please describe process or provide source.


texts: Why/how does exposure to noise cause cochlear hair-cell loss?

texts:
I am trying to understand why listening to loud music - e.g. concerts or earphones at high volume damages hearing.

According to the National Institute on Deafness the cause is physical.

  Most NIHL is caused by the damage and eventual death of these hair
  cells. Unlike bird and amphibian hair cells, human hair cells don’t
  grow back. They are gone for good.

But I don't understand why/how would noise - which should basically lead to higher amplitude waves in the basilar membrane, induce damage and death of these hair cells?


texts: What are the environmental conditions for SARS-CoV-2 to survive?

texts:
What do we know about the environmental limits for nCoV to survive outside the body? For example, in:

In open air
On surfaces
In water

What are the limits for temperature, humidity and air pressure, where the virus, can or cannot survive?


texts: Why does a housecat (or other predator) play with it's food before killing and eating it? Does it make the food taste better?

texts:
I've read a couple people theorize that a cat playing with a mouse causes the mouse's body to be flushed with adrenaline before the final kill and that this adrenaline makes the meat more tender/easier to digest/more nutritious etc.

Is there any evidence to support the idea that by playing with it's prey the cat is making it taste better or easier to eat?


texts: What Freshwater Fish Are Affected By Magnetic Fields

texts: I am interested in knowing which freshwater fish are affected by magnetic fields.  I've heard that Lake Sturgeon are, but would like more references. This is for a project that will have buried 3 phase power cables.


texts: What is the biological name of this plant?

texts: The plant was observed in a rural area near Digha.


texts: Does ATP production increase with oxygen availability?

texts:
I'm not a biologist so pardon any ignorance on my part. I'm working on a speculative evolution project and I'm looking to understand how the partial pressure of oxygen effects the maximum aerobic performance of muscle. This paper gives the maximum aerobic performance of 100 Watts per KG of muscle. This limit is stated to be observed for both insects and vertebrate fliers and is in turn used to calculate the aerobic flight capacities of various animals. The paper also mentions that squamate muscle tissue can achieve 450 W/kg anaerobically.
I have used the equations listed in the linked paper to calculate the size limits of my speculative world's fauna. The only problem is that this assumes an aerobic power output of 100W/kg of muscle. It is my understanding that aerobic respiration in muscle cells is driven by ATP production and that ATP production is dependant on a constant supply of oxygen. It seems logical that the maximum aerobic power output should be higher if there is more oxygen available.
For context, the atmosphere of this speculative world contains 13.5% O2 at a pressure of 12atm. This equates to a partial pressure of oxygen of 1.62 - approximately ~8x higher than our current atmosphere. In these conditions, there is 8 times the amount of oxygen available for respiration. If oxygen availability is the sole factor in ATP production (thus aerobic muscle power), then this means the aerobic power output would net 800W/kg of muscle (assuming the biology of these creatures are the same as known animals). This is almost double what lizards can produce anaerobically which doesn't seem likely.
My question is how would ATP production scale with available oxygen? I assume there comes a point where mitochondria simply cannot process ATP any faster, which would imply a maximum aerobic power output. I have read that some athletes breathe canned air to reduce fatigue. Does more oxygen equate to more power or does it simply mean that muscle cells would not fatigue as quickly? If I've made any mistakes in my reasoning then please correct them. Thanks.


texts:
I am interested in learning about attempts to treat adult individuals suffering from a genetic disease in which the underlying changes in the DNA of the gene are understood.

(i) Are there approaches that use drugs or do they use DNA corresponding to the normal DNA?

(ii) Are there attempts to reverse the condition or only ammeliorate it?

(iii) How near is such gene therapy to clinical use and for which diseases?


texts: How does the brain know where a signal came from? What is the addressing system

texts:
I am an electronic engineer so I am thinking about this from an electronics outlook.

How does the addressing system work, As I see it, the nervous system is small parallel branches attached to larger "serial" lines (spinal cord).

The serial line is then attached to the brain, but how does it then figure out where the message came from and then get the message back to the place it came from.

If I were to build a robot I would have an addressing system with each message and maybe some kind of error checking to make sure the messages don't become corrupted, but as it's not an electronic system I don't see how the brain could possibly do this. unless it is a fully parallel system and there is a single wire going from every sensor back to the CPU..


texts: Why is the spirit bear/Kermode bear a subspecies of the American black bear Ursus americanus?

texts: The Kermode bear Ursus americanus kermodei is only found in British Columbia,Canada. The Kermode bear has single nucleotide polymorphism at the melanocortin 1 receptor gene (mc1r) locus which cause the white color. 1 out of 10 indviduals are white and are refer as Kermode bear. However, is the black version of the Kermode bear still a Kermode bear Ursus americanus kermodei? If not, why?


texts: What is the purpose of the brown louver-like structure on the underside of a mushroom?

texts:
On the underside of the cap of a mushroom is a structure with many brown leaves closely spaced together like slats or a louver.

What is the purpose of this structure?


texts: Why are large amounts of DNA required for analysis?

texts: I know PCR is used to create large amounts of copies of genes and that it's a scientific breakthrough but want to understand why. Why do we need large amounts of DNA to be able to analyse it, to utilise it. Isn't a single DNA molecule enough?


texts:
Normal air consist of oxygen, CO₂ and nitrogen, with traces of water etc.

Now imagine displacing all gasses except oxygen with water vapour. By water vapour I don't mean hot steam or fog. Just gaseous water.

The question is would it be beneficial or harmful to human, and how much so?
And assuming it's not deadly, in which circumstances could it be useful?

One thing I am wondering in particular is deep dive and high altitude applications. Having no/low content of nitrogen in such an artificial air mixture would help to avoid decompression sickness. And one would think water vapour is at least cheaper than pure oxygen (also might be safer and have less side effects).


texts: Why are there ghost images of objects just out of focus

texts:
I have observed an interesting phenomena with my vision lately. I just think I have never reflected over this before but it might always have been this way.

I am nearsighted and have no problem with double vision as long as an object is in focus, either with or without glasses.

However when I take my glasses off and look at, e.g. my phone screen, and push it slowly just out of focus, there is a phase where multiple distorted weak ghost images appear before everything just becomes a more Gaussian like blur. It is especially clear with bright lines on a dark surface.

I do not believe that there is anything else wrong with my eyes, since as soon as an object is in a range where I can focus on it, all ghosting disappears.

I am interested in knowing if anyone else observes this.

But more interesting is what are the possible optical properties of the eye that contributes to this, or is it a property of how our brain processes the input from the eyes.


texts: Is flowers nectar secreation influenced by bees/pollinators?

texts:
Nectar secretion by flowers is influenced by many environmental factors e.g. water supply and air temperature [1].

My question is: do bees (or any other pollinator) influence it too?

I can imagine every bee's visit takes away a certain amount of nectar from the flower. Then following the flower nature, it should produce nectar again (if there are the right conditions, e.g. enough water).

[1] https://www.jstor.org/stable/2468960


texts: What is the minimum functional biological light sensor?

texts:
As a follow up to this question regarding the evolution of the eye, it was suggested that primitive eyes only needed to evolve a light sensor and could perhaps use the existing biochemical cascade infrastructure.

What is the minimum of this biological light sensor? Please provide a detailed biochemical description of how many proteins are involved and their interactions which can be "hooked up" to the existing biochemical cascade infrastructure. (to the best of our knowledge)


texts: Does Alzheimer affect more than day-to-day memory?

texts:
I know that Alzheimer's damages a part of the brain called the hippocampus, which has a central role in day-to-day memory.

But, could it affect also on things in other memory centers, things such as taste and moves?


texts: Is there any way to cultivate viruses without cells?

texts:
I know what viruses are. They replicate only inside the living cells, and so on, and so on.

I just interesting maybe there is some progress in this field. I don't know exactly, but I suppose before invention of the nutrient agar microorganisms were cultivated on substrates like eggs, potatoes, meat etc. Perhaps there is the same story for viruses.


texts: Have bacteria evolved antibiotic resistance in a laboratory setting?

texts: Is it possible to breed a strain of bacteria in a laboratory setting so that it gains resistance to an antibiotic, replicating the kinds of resistance seen in wild, and has that been done?


texts: Capture recapture for only two visit assuming a open population model

texts:
I have a study system where I’m doing a capture recapture analysis. I mark fish in one year and I’m recapturing a subset of them the next year.

I only have 2 capture events. Since a lot of time has passed, relative to the fish, between the two episode of recapture, I cannot assume a closed population model. Is there an alternative?

What mark-recapture model would be best for this situation given that I want to compute a recapture probability?


texts: Why are H+ ions pumped out instead of in during cellular respiration

texts:
During cellular respiration in both mitochondria and aerobic prokaryotes, the Electron Transport Chain pumps H+ ions out of the matrix or cytoplasm to create a H+ concentration gradient. This forces the H+ ions back into the matrix or cytoplasm forcing ATP synthase into action.

I was wondering, however, why the H+ ions are pumped out of the matrix or cytoplasm, instead of into it. For aerobic prokaryotes, and the early mitochondria (which were prokaryotes living on their own) pumping the H+ ions out of the matrix or cytoplasm means pumping them into the outside world, a very uncontrolled environment. There is nothing to prevent the H+ ions from diffusing out, making the pumping completely inefficient, if not pointless. Wouldn't it make more sense to pump the H+ ions into the matrix or cytoplasm, where the H+ ions cannot diffuse, resulting in much higher efficiency?


texts: I've been told that flies take off backwards, but I haven't really been able to prove it to myself. The closest I've gotten was noticing that they fly into window glass back-first, with their heads pointing up. Is that how they take off?


texts: Why is trypsin digestion required for proteomic studies?

texts: I know that trypsin is used for proteomic studies, but I do not understand why trypsin digestion is necessary/important.


texts: Is there any example, where cooperative behaviour of predators induce fear in prey population?

texts:
I am basically from math background and doing Ph.D in mathematical biology. So I am not so efficient in biology. But my problem based on cooperative behaviour of animals during hunting which is related to the animal behaviours in ecology.

We know that different animals show cooperative behaviour during hunting (or, group hunting) such as wild dogs, lions, chimpanzees, birds, spiders, crocodiles etc.
We also know that fear of  predator (predation risk) reduces the  growth rate of prey population. Now, I am looking for
example(s), in which prey population does not fear predator but cooperative behaviour of predators induces (creates) fear in prey.


texts: How is human biological clock modelled in modern science?

texts:
Im an engineer by education and i program a lot, so the question sounds weird to people from other disciplines.

Im trying to better understand the human biological clock. Yet i do not really know what it is. I read about clock genes, endogenous cycles, and other observed phenomena that is time sensitive or cyclical in nature. But is there a centralized model of what the circadian rhythm is or how itis exhibited within the human body?

For example an electrical clock can be modelled with feedback loops or electrical flip flops that control the timing. Ive seen the heart modelled as Van Der Pol oscillator.

Does modern science have some notion of how the "master" clock within the human body work? Is there a feedback or an oscillator model of the master clock?

Thank you for any articles or keywords that ican use to research this question!


texts: Does a woman contain all the genes needed to make a man?

texts:
I know the answer of inverse is at here, but how about this question?
I also read this question, can I imply to human that a woman can also contain all the genes needed to make a man?

Edit:
I think everyone has  the ability of being a man or a woman in terms of their DNA, and that their gender is just determined by the presence of SRY.
Is my concept correct?


texts: Do circadian hormones fluctuations follow sleeping patterns or the time of day?

texts:
It is said that testosterone and cortisol are at their highest early in the morning, at 8 am, and lowest at night.
What happens, though, if someone regularly goes to sleep at 8 am and wakes up in the afternoon/evening over a long period? What happens if sleep times are inconsistent, sometimes sleeping overnight and sometimes in the morning? Do hormonal fluctuations follow the sleep pattern or do they follow the time of day?


texts: Discalimer: I am not a biologist. I am modelling E.Coli growth and in the Wikipedia gif one can see observe some groups where the bacteria are one next to each other, oriented at approximately the same angle. I did some simulations and obtained similar results. Is there any reason why this happens?


texts: How to correctly and accurately identify a few species of trees from their leaves?

texts:
I want to identify a tree from one of the 12 species listed based on observing their branch and leaves. Is there quick and neat way to do it?

Red Oak, White Oak, Red Maple, Striped Maple, Tulip Poplar, Black Cherry, White Pine, Virginia Pine, Dogwood, Hickory Species, Sourwood and Cucumber Magnolia.

Thank you!


texts:
I found this snake near a small garden.

Location: India (Hyderabad, south India)

Temperature: 38 oC

Humidity: 28%

Time: 2 hours past noon (2PM).

Similar snake was found in drainage of our locality.


texts: Can life occur from a fertilised egg cell, in which both the egg and sperm possess an extra copy of a chromosome?

texts: Patau, Edward, and Down Syndrome are all the result of either the egg or sperm cell possessing an extra copy of chromosome 13, 18, and 21, respectively. However, what would be the outcome if both cells possessed an extra copy? That is to say, if the fertilised egg cell is left with not three, but four copies of a chromosome?


texts: What prevents platelets from clotting regular blood vessels?

texts: Platelets clump together to initiate clotting, but, why don't platelets clot within healthy tissue and cause heart attacks all the time?


texts:
Do all psychoactive substances induce tolerance eventually?

For that matter, do all receptor-binding substances induce tolerance eventually?

It seems certain that different substances take different amounts of time to produce tolerance. Is there a pattern here? Do all receptor antagonists take similar amounts of time, or does it vary by receptor type?

(How do we know medications are not a zero-sum game?)


texts: Sometimes men wake up with an erection in the morning. Why does this happen?


texts: What is this fungus growing on tree stumps?

texts:
Location: Austria, Vienna, Ottakring Forest

Time: 2019, Feb 2, 16:02 local time

Size:

From below; lamellar structure:

Some more angles:

I found many tree stumps nearby covered by moss, but only this one displaying the fungi. I am not knowledgeable enough to determine the species of the tree.

I first suspected a Ganoderma, but none of the species listed on Wikipedia looked very similar.

A better bet might be Lenzites Betulina although the pics on Wikipedia always seem more richly coloured than mine. You can check many pics of L. Betulina candidates on mushroom observer. The L. Betulina in this Video also seem to have more marked rings.

Edit:
After some searching I am also considering Trametes Pubescens, as Wikipedia remarks:

  Unlike most other turkey tail-like species of Trametes, the cap surface lacks strongly contrasting zones of color.


texts: What insect is this? (Black body two orange lines in its back and six legs)

texts:
I found this today in the library while studying. I am very curious to know whether this particular insect has a name that I can look up and find more information about:

Full length is almost one centimeter. It doesn't bite or anything. It has lots of small hairs in its back (similar to cockroaches and ants) and has a tail that a white sticky substance comes out from.


texts:
I have found the following definition on Wikipedia:

  An organic chemical compound (or related set of compounds) is called a
  vitamin when the organism cannot synthesize the compound in sufficient
  quantities, and it must be obtained through the diet;

That doesn't seem to exclude essential amino acids and essential fatty acids though, and those are also organic chemical compounds that by definition can't be synthesized in sufficient amounts.

So is the definition incomplete?


texts: Regulation of V. cholerae virulence factors

texts:
So I know that several different environmental signals, such as pH, bile, and temperature, regulate virulence gene expression in V. cholerae. Specifically, they control expression of the genes encoding the toxin co- regulated pilus (TCP) and cholera toxin (CT).

But what are the two key (main) transcriptional regulatory proteins that control TCP and CT expression, and where is each localized in the bacterial cell? Also, what does each protein do?

I know that the proteins involved are ToxR/S, ToxP/H, and ToxT, but I don't know which are the MAIN ones and why...


texts: Where am I going wrong in a Reactive Oxygen Species Assay done in N9 cells?

texts:
I have followed the modified protocol that was given to me by my senior (who was using for his RAW 264.7 cells - Reference article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308605/ ) for assessing ROS in N9 cells.
But, I am not able to standardize it in our lab ... every time there are variations in the results.

Protocol

Seeded 10,000 cells per well in a 96 well plate.
After 12 Hrs of growth, the spent medium is discarded and the cells were washed twice with PBS.
After the PBS wash, 50uM DCFDA was prepared in PBS and 100ul/well was added in 96 well plate and then incubated for 30 min at 37oC and 5% $CO_2$.
The DCFDA was removed from the wells, immediately and cells were washed twice with PBS.
After the wash, to standardize the protocol, the cells were treated with 10uM, 30uM, 50uM ${H}_{2}{O}_{2}$ as a positive control and 1mM and 5mM N-Acetyl Cysteine was used as negative control.
And a set of cells not treated with any compound (DCFDA/${H}_{2}{O}_{2}$/N-acetyl cysteine) are also used as control.
After treating with the compounds, the fluorescence was recorded in multi-plate reader at (excitation -485 nm and emission-530 nm) different time points with a 10 min interval - T0, T10, T20, T30, T40, T50, and T60.

We could not see in difference in different concentrations of ${H}_{2}{O}_{2}$ (newly purchased) and also with N-acetyl cysteine. We would expect to see some difference.

It will be a great help if you can suggest me where I might be going wrong with the protocol or is it anything to do with the seeding density of the cells.


texts: Is there a list with common mistakes in database entries?

texts: I am a university student at the department of Biology. As part of my assignment for the subject Bioinformatics, I was asked to refer to common mistakes in biological database (e.g. Uniprot). For instance, "dehydrofolate reductase". Is there any list with such common mistakes? Otherwise, in your own experience, could you mention some examples of similar mistakes that you meet regularly?


texts: What species is this colourful caterpillar?

texts: What species is this colourful caterpillar found on a road in Central Europe?


texts:
Why is ebola disease does not cured on elevating body temperature by body defense system?
Can we cure it either by elevating or reducing body temperature (in ice bath) and creating hostile environment for virus?


texts: What is the current scientific consensus on how insects innately know what is food and not food? If they are introduced to new food sources do they experiment with eating the new food? Could you teach a preying mantis to eat beef?


texts: Are there mechanisms that limit the amounts of time conjugation and F-plasmid transfer can happen? If yes, what are they?

texts:
Not all bacteria have acquired F-plasmids through conjugation. Some of the mechanisms for this are unsuccesful conjugation events (mechanical disruption), no transfer due to integration in bacterial chromosome, etc (See previous question and answer).

Now I am wondering if there are also mechanisms that self-limit the conjugation and transfer of F-plasmids. For instance that a bacterium can only transfer its F-plasmid once during its lifetime.


texts: Do animals get sick from eating dirty food or eating off the floor?

texts:
Humans have very strict tradition of hygiene, such as washing hands before eating, using utensils, and in general keeping as much distance between food and dirt as possible.

At the same time, most animals would eat off the floor or eat food with foreign particles stuck to it ( after being dropped on the floor). Many animals, like cats groom themselves, practically licking off (and swallowing?) dirt off their coats.

Do animals suffer adverse effects, such as indigestion or disease from consuming food that is dirty by human standards?

Or is it something about the human digestive system that cannot handle the same kinds of dirt that animals can?


texts: Nernst equation and equilibrium potential

texts:
Solutions A and B are separated by a membrane that is permeable to Ca2+ and impermeable to Cl−.
Solution A contains 10 mM CaCl2 , and solution B
contains 1 mM CaCl2.
Assuming that 2.3 RT/F = 60 mV, Ca2+ will be at electrochemical equilibrium when

(A) solution A is +60 mV

(B) solution A is +30 mV

(C) solution A is −60 mV

(D) solution A is −30 mV

(E) solution A is +120 mV

(F) solution A is −120 mV

(G) the Ca2+ concentrations of the two solutions are equal

I eliminated A,B and E because of the +ve sign immediately, and G because it doesn't take into account the electrical potential factor.
I also understand the general idea (that Ca2+ ions will cross the membrane but Cl- won't so it will stop when solution A is negative enough for the electrical gradient to be > concentration gradient) but I don't know what to do next.
Using Nernst equation (here's the version in my book) I got that the equilibrium potential is about -60 mV (I did -61log(10/1))
But the book's answer is D which makes me think I might have a huge misunderstanding in the principle itself.


texts: Why are published chromosome counts for polyploids often incorrect by an integer multiplication factor of the original diploid like count?

texts:
Why are published chromosome counts (done using techniques such as root smashes) for polyploidy flowering plants often incorrect by a multiplication factor of 2 or 3 from the original diploid like count?

When published chromosome counts for some polyploidy orchid and rhododendron species were updated such counts showed a multiplication of the original more diploid like count rather than a incremental refinement to a slightly more accurate count already in the polyploidy range.

See Ploidy Orchids

In rhododendron multiple counts of 26 chromosomes for R. austrinum, atlanticum, and luteum have been updated indicating a number of chromosomes for these three species is closer to 52 chromosomes.

Is there something about the way a polyploidy flowering plant species undergoes meiosis or mitosis that causes such miscounting to be the chromosome count for closely related diploids?


texts: Autoimmunity - negative selection of T-cells - APC

texts:
Through negative selection of T-cell in the thymus T-cells lose the possibility to react to antigens which are "body own" -> self antigens.
Though there are more than just this negative selection for preventing T-cells recognizing own antigens some T-cell become self reacting.
This T-cell in our case cd4 T-cells can recognize antigens presented on MHC II complexes by APC cells.

And the question is:

Who presents the self-antigens to the wrong selected CD4 T-cell, which leads to autoimmunity? How does the APC cell get this self-antigen in the first place?


texts: What are two butterflies doing when they fly together, 'hitting' each other?

texts:
I've Googled this subject extensively but couldn't get an answer:
My country is full of butterflies and moths, I've seen a lot of butterflies performing what looks like some kind of fight or mating ritual: Two butterflies of the same species flying together and 'hitting' each other, and when they do that a noise can be heard, I don't know if it's from the actual 'impact' or a noise they produce, but sometimes it's very loud and resembles an electrical arc.
I'm extremely curious on what that is all about. I thought they were actually mating but I've seen so many species doing that, including some that I know don't mate like that.
I live in Brazil - in the humid southeast region.
Any help or clue is really appreciated. I'm putting a link to a YouTube video below which shows more or less what I'm talking about, but strangely the butterflies in the video aren't of the same species:
https://www.youtube.com/watch?v=FpRQLtyIRog
Thank you for your time.


texts: What is the scientific name of this plant that is possibly called ogre ears?

texts:
I already did a reverse image search and came up with "ogre ears" as a name for this plant. However, this name is associated with other plants: Crassula argentea and Crassula ovata. What is the scientific name of this plant?

Thanks


texts: Theoretical Rules Governing Life in the Universe

texts:
Obviously, no one can know what life on another planet would look like until we discover such life. However, scientists have speculated that (if I'm not mistaken) all living things must be carbon-based. I think it's also assumed that all life requires water.

Are you aware of a published list of theoretical "universal life guidelines"? For example, I would speculate that locomotory organs (e.g. legs) tend to evolve in pairs (one-legged animals unlikely), and that microscopic creatures have no legs at all (replaced by cilia, tentacles, etc.).

Again, this isn't hard science; I'm just interested in knowing about the speculations of various scientists.

Let me add a few details to make my question more clear. On Earth, most life can be divided into a handful of kingdoms (e.g. plants and animals), and animals are commonly divided between invertebrates and vertebrates. Vertebrates are generally bigger and are bilaterally symmetrical (as are some invertebrates).

I would speculate that the laws of physics dictate that really tiny organisms have locomotory organs like cilia, and some may have just one cilia.

However, larger, more complex animals possess bilateral symmetry. This includes not just vertebrates but arthropods and even some mollusks (e.g cephalopods). There are some obvious advantages to bilateral symmetry among larger life forms.

So, if we discovered a planet with a similar size to Earth, we probably would not expect to find fifty-feet amoebas crawling on land. We might speculate that most large terrestrial creatures would have paired leg-like organs - and probably one or two pairs, not 100. Similarly, paired eyes help with navigation and depth perception.

But those are just very general personal guesses. Lots of alien life forms have been created for science fiction movies, but I wondered if the scientific community has created some more rigorous theories about what alien life forms would really be like.


texts: Mechanism to limit the exponential growth of the number of ancestors that are n-generations away from an organism?

texts:
The context is organisms with sexual reproduction, with 2 parents per organism.
Construct the family tree of one such organism, back into geologic time.

Take a(n) as being the number of ancestors that are n generations distant.
The function a(n) has an exponential character (at least in the beginning, with n sufficiently small).

For 2^n, simple math gives:

After 20 generations, you have about 10^6 ancestors.
After 30 generations, you have about 10^9 ancestors.
After 50 generations, you have about 10^15 ancestors.
After 1000 generations, you have about 10^300 ancestors.

I've read one estimate that there are about 10^80 atoms in the Universe. What does this mean?

It's important to note the the members of generation n usually aren't all alive at the same time.
As an example, for humans, the birth-dates of generation-20 are roughly between the years 1720-1520, for example.

It doesn't take very many generations for a(n) to exceed p(t), the population as a function of time.
This is accounted for (at least for sufficiently low n) by the fact that a(n) represents organisms that aren't alive simultaneously, while p(t) does.
I understand that.
But, this effect, important as it is, seems to be linear with time.
As such, it doesn't seem capable of limiting the exponential growth of a(n).

In this context, inbreeding is often raised.
But, in my opinion, inbreeding is not germane.
Here, all that matters is that each organism has 2 parents.
Period.
Whether or not inbreeding was involved doesn't change that basic fact.
All inbreeding means is that one ancestor is a member of more than 1 generation.
That's not relevant to my question.

Edit later:
No, inbreeding is germane. It means that 2 members of a(n) can have the same two parents in a(n+1). That reduces the exponential growth of a(n).

It seems that a(n) must be limited by something, for sufficiently large n. What is that something?


texts: Cellular specific mass (in grams-dry-weight per pico liter)?

texts:
What is the cellular specific mass, in units of pgDW (pico-gram dry-weight) per pL (pico liter)?

I suspect there is some variability between cell types, but this variability must be limited. Perhaps bacteria and mammalian cells are different, but the number shouldn't change much among bacteria. This is just intuition, I could be wrong.

So, what is the cellular specific mass, for different cell types (assuming there is limited variability, so this is not an infinite table)?


texts: why do sodium channels close with excessive extracellular potassium ions in cardiac myocytes?

texts:
When there is an excessive concentration of potassium ions outside cardiac myocytes, the membrane potential surely goes up. I would have thought that this would make it easier for the membrane potential to go up past the threshold level, opening sodium ion channels and causing an action potential like at a synapse.

However, I understand that as the high concentration of extracellular potassium ions actually deactivates voltage gated sodium ion channels as opposed to opening them. Why does this happen?

Sorry if this question is pretty basic. We haven't covered anything nearly as complicated at school, especially not about cardiac cells.

Thanks for answering!


texts:
B-CELL EPITOPE PREDICTION

Regarding this article:

"Such a molecule can be synthesized or, in case of a protein, its
gene can be cloned into an expression vector."----- is a particular
line in this article. What does expression vector mean here??
"antipeptide antibodies"---- what are these?
"immunogenic peptides"----these are basically epitopes, am I right??


texts: Why do ion concentrations change with different secretion rates in pancreatic juice?

texts:
Why is it that when secretory rate increases in the pancreas the concentration of chloride ions decreases, and the concentration of bicarbonate increases in the production of isotonic NaCl secretion?

The modification that goes on in the duct of the acinus is dependent on flow. If the flow is faster, then less ions can be reabsorbed from the primary secretion. In the pancreas, chloride ions are removed, so surely their concentration should go up as the flow increases?

Bicarbonate on the other hand is added to the primary secretion in the duct. So shouldn't its concentration in the secretion stay the same or even increase as flow increases?


texts: Brainbow fluorescence labeling technique

texts:
I have this picture describing the Brainbow system here:

The paper I am reading says it uses Cre-lox recombination to express a certain color. If the cell in question was expressing a yellow fluorescence then what would the construct in that cell look like in terms of the picture given? Would it just be a single line with the UAS, EGFP, and mKO2 in that order or would it be two lines, wone with the UAS and EGFP and on with the UAS and mKO2?


texts: Can microorganisms (e.g. bacteria) be damaged or killed by 253,7 nm light?

texts:
The question arose in a hospital, where I saw these flyers advertising lamps that emit such light. It was claimed that they can clean the air of microorganisms up to an arbitrary degree.

Does anyone know if that is a thing? (If it is, doesn't it also kill the beneficent types of microorganisms?)

Online I found quite a bit on the matter, but only from other distributors of similar installations.


texts: I am trying to view several data tracks in the modENCODE GBrowse genomic browser. However, the site is so slow, it is practically unworkable. Is there a faster way to explore the data?


texts: How does a tree trunk sprout and grow after being cut?

texts: After I cut trees into logs and remove the branches in winter, they start growing. They sprout out and grow completely normal looking stems and leaves and maintain them all summer. The sprouts mostly appear around the cut branches.  Sometimes they last all winter and grow for another year. How does it find the energy and water necessary to maintain and grow these stems without ground connection and a water source?


texts: Is the signal peptide always cleaved during protein synthesis in the ER?

texts:
My university supervisor said that the signal sequence is always cleaved, however my text book differs.

What I gather from my text book (though it isn't very clearly stated so i'm not sure) is that:

A protein that is meant to be completely extracellular (or go into a membrane-bound organelle) will have only a signal sequence which will be cleaved by signal peptidase.

If there is a protein that is meant to have just one transmembrane domain, it can either:

a) have a single signal sequence, however this will not be at the start of the N terminus that is being translated. If there are more negatively charged amino acids before the signal sequence, then when the signal sequence binds into the translocon complex this beginning 'tail' will be threaded through as it is repelled from the more negatively charged cell interior. The amino acids following the sequence will be more positively charged to stay in the cytosol rather than passing through to the ER lumen. This will determine the directionality of this single-transmembrane-domain strand.
//Alternatively there can be one signal sequence and the amino acids before are more positively charged and after are more negatively charged, so you get the reverse situation where the already synthesised strand remains in the cytosol and the rest of the polypetide is threaded through as it is synthesised. Either way, this involves just one signal sequence.

b)The polypeptide can have one signal sequence and one stop-transfer sequence, with the charges on the surrounding amino acids determining directionailty, and then one of the signal sequcne or stop transfer sequence may be cleaved by signal peptidase.

Multipass proteins have a series of signal peptides/start-transfer and stop transfer.

But if my textbook (or rather what I understand from it!) is correct, then some but not all signal sequences are cleaved. So how does the signal peptidase know which to cleave?

I would really appreciate if someone could tell me answer this and also correct me where I have gone wrong in my understanding.


texts:
There is a three edged stiletto (weapon, not shoe) with a triangular cross-section that is often touted as being "extra dangerous" because of the triangular puncture it makes, and its copper construction. The claim is that the copper inclusion causes something colloquially referred to as "blood poisoning."

Is there any basis to the idea that a copper blade would cause some kind of secondary toxic effect?


texts:
Phosphene from rubbing the closed eyes where first described at least since Ancient Greece, but I caught myself thinking that I wouldn't want to try it out. So I wonder, how safe it is to actually rub closed eyes or put pressure on the human eye in general? Can frequent but small, or rare but sharp, application of pressure cause myopia or other eye disorders? What is the maximum pressure before the eye is damaged? What happens with the eye if you accidentally hit it?

I remember several times during my childhood accidentally poking myself in the eye with a finger—the experience was very uncomfortable, I couldn't even open the eye for several minutes, but I don't think anything happened to my eyes since then, and my myopia was probably caused by any other factor than pressure damage.


texts: Foveal ganglion cell density (Tay-Sachs Disease)

texts:
I’m currently reading on Tay-Sachs disease and have stumbled upon something regarding the typical “cherry red” macula symptom.

On the one hand it is mentioned that the macula is almost devoid of ganglion cells (GCs) and this actually the reason for the high acuity in this region since there is not obstruction of light [Suvarna JC, Hajela SA. Cherry-red spot. J Postgrad Med 2008;54:54-7].

On the other hand google books gives me numerous textbooks that highlight the fovea as the location of highest GC density and conclude that this leads to the high acuity because a GC only receives information from one or two cone cells.

I guess both are correct but how does one fit the other? It seems contradictory to me.

To be precise some sources specifically mention the boundary regions of the central fovea to have the high GC density, this could leave the fovea devoid of them and therefore combine both facts, however if this is correct I still wonder:

1: Where are the GCs that the cones in the central fovea are connected to?

2: Why is the “cherry red” spot in the macula so large on all the pictures. If my explanation is correct only the tiny area of the central fovea should be red and the surroundings the complete opposite due to the high GC density, right?

I’d really appreciate if someone could shed some light into this.


texts:
Standard 'Explanation':
I've seen countless neuroscience articles and experts explain that 'cortical gyrification is advantageous because it increases surface area which obviously increases your intelligence' (e.g. this wikipedia article).
Question(s):
But this explanation is woefully lacking, why does surface area matter at all? That implies  that somehow empty space is contributing to cognition (since the alternative is that space being filled with brain matter).
My best guess:
The only guesses I have are that perhaps it functions like skip layer connections in Residual ANNs. This section of the wiki page, says it is advantageous because 'it allows neurons to be closer together' which I guess kind of corroborates my idea?
Question(s):
But it is still far too vague and speculative. Why could these same wiring patterns not just emerge within a smooth-surfaced brain without wasting space? Also, does this imply that if you got more brain matter to fill in these spaces later your intelligence would decrease?


texts: Why do reptiles still move even after death?

texts:
I saw a video in which a decapitated snake head still tried to bite.

I also saw a video in which a man was hit by the moving tail of a dead crocodile.

So why do reptiles move even after death?

http://en.wikipedia.org/wiki/Reptile


texts: How does a test like the Natera Panorama distinguish the child's genome from the mother?

texts:
Blood tests on an expectant mother, like the Natera Panorama, are now being used regularly to screen fetuses for chromosome abnormalities. At my wife's recent prenatal visit, she wasn't really even asked if she wanted the test; apparently it's standard in that office. I understand some of the science of how such a test could be performed. When the placenta implants, some of the fetal cells get into the mother's bloodstream, and even though the chromosomes from those cells are breaking down, these pieces can be scanned for the markers for genetic disorders and gender. But I don't understand how the fetus's maternal chromosomes can be identified against the background of the mother's genome.

For example, one of the things that they can rule out with pretty high certainty is Monosomy X: only one X chromosome and no Y. I can see that after determining the mother's genome, it could be determined if there was no evidence of an X or Y from the father. But how would they know if an X was not contributed by the mother. If they are looking through decomposing pieces of DNA in the mother's bloodstream, are they not guaranteed to find each of her X chromosomes, whether or not the fetus has a copy of either one? How can they determine that any piece of a maternal fetal chromosome really came from the fetus rather than from the mother?

Disclaimer: I do not endorse Natera over any of their competitors. I mention them by name only because they are the only ones I am familiar with.


texts: Can you suggest me some books/articles about how female birds indicate receptivity to copulation?

texts:
Where can I find informations about the topic? I need to find some examples.

I also really need this particular information: I know that many female mammals display lordosis behavior that indicate receptivity to copulation, but can birds do that or it is a peculiarity of mammals only?


texts: Does anyone know what insect species this is?

texts:
The insect has an approximate length of 2.5 cm and It was found in Panama, Central America.
It was living hidden between the leaves of a papaya tree (Carica papaya).


texts: How does the brain instinctively know the math behind Newtonian Physics?

texts:
A 10 year old child does not have the intellectual power to accurately calculate the energy required to throw a ball an arbitrary distance. Yet they are able to accurately throw a ball at a distinctive target.

Similarily, we often "instinctively" know an approximation of the amount of energy and force required to accomplish certain tasks, even considering that many of us have minimal knowledge of the mathematical complexity behind the tasks.

How does the human brain know the values of force, energy etc. required when accomplishing certain tasks, while being ignorant of the mathematics behind the Newtonian Physics of the task? Is it just a game of "guess and check"?


texts: Is there any way to tell if a gene is functional for an individual with only a reference sequence and the individual's sequence of the gene?

texts: I have gene sequence of a ton of individuals within a subspecies from cdna and the ncbi IDed sequence as well. Is there any way to tell using just the sequence that the gene for an individual is non-function or only partially functional?


texts: Do all plants photosynthesize with equal efficiency?

texts:
Just what the title states.

Given identical, necessary and favourable conditions (Probably nutrients, humidity, and light but what I mean is all necessary requirements are fulfilled) - Is photosynthesis equally efficient in terms of the amount of sugar/carbohydrates generated by all plants/trees, or are some plants/trees more adept at it?

My background in biology/botany is high-school, so my list of necessary requirements may be lacking for which I crave your indulgence


texts: What would kill you first water or cola?

texts:
After discussing this with some colleagues, I devised the theory that you could drink more coca-cola in a single sitting than you could water, without killing you.

Defining the volume it would take for one of the liquids to kill you as the 'x volume'.

Thus the hypothesis goes that the x volume for water would be lower than that of coke.

This is based on the notion that water would affect the body's water potential significantly more than the cola solution. For instance, the large volume of water would diffuse, via osmosis, into your blood and this would reduce the water potential of the blood, which would in turn diffuse into your cells which would in turn damage the micro environments and prevent proper enzymatic activity in all aspects of the cell cycle: which would have devastating affects on the brain function. Given enough water: something that can be read about here (water intoxication).

Coca-cola on the other hand which has an acidic pH -- though I'm not entirely sure of it's water potential -- would not have the same disturbance on somatic cells in the body due to the acids and sugars. However, although the large consumption of cola may have longer term effects: would the x volume of coca cola be higher than that of water?


texts: Why are hens so different from other birds?

texts: Hens lay many eggs during their lifetime (at least, I don't know of one which can lay more eggs) and they can't fly. Compared to other domestic animals it seems to me they are the least capable of defending themselves or escape if it comes to be left alone in open wild. What is their evolutionary story?


texts: How do injected purified anti-D antibodies prevent the natural production of antibodies in order to prevent Hemolytic Disease of the Newborn?

texts: Treatments involving Anti-D antibodies are given to pregnant women carrying Rh+ fetuses when the mother has an Rh- blood type in order to prevent Hemolytic Disease of the Newborn during the 2nd pregnancy. The anti-D antibodies are injected during later stages of pregnancy and right after birth in order to eliminate any Rh+ blood cells in the mother before D-antigen antibodies are produced naturally by the mother. If antibodies do not attack cells directly, what stops the mother's macrophages from engulfing the antibody bound Rh+ blood cells, becoming an antigen presenting cell and hence initiating the process of producing antibodies and saving the antigen in memory cells? Are the Fc receptors on the macrophages not compatible with the injected anti-D antibodies?


texts:
I was surprised to learn that worker ants in some species live many years. I would have expected a lifespan of a few weeks or months (which is apparently the case for many species).

What factors might account for the length (and/or variation) in ants' lifespans?   (ie, is there some evolutionary preference? Some fundamental limit on the reproductive capacity of the queen?) Is there any relationship between these lifespans and different structures of ant communities?


texts: What amount of light energy is required to produce one O2 molecule? How about one molecule of NADPH?

texts:
I know that for each O2 molecule, a total of 8 photons are required (4 per photosystem). Would the amount of light energy required be E=hc/wavelength using 680 and 700? Or would the energy from the initial incident light need to be taken into account (as in when light initially hits the photosystem and gets funneled down)?

Additionally, I know that one NADPH  is produced per 2 electrons. I am puzzled as to how this can be transformed into light energy? Would the amount of light energy required be that of PSI and PSII once again, due to the Z-scheme that ultimately leads to the NADPH production?

I appreciate any help.


texts:
Does transferring blood between two people also transfer all the white blood cells?

Why can't AIDS victims with low t-cell count just get blood transfusions till they have more t-cells? Why can't someone who's over a cold give blood to someone with a cold to cure them? I know this is silly, but I really want to know why this won't work.


texts: How much current is required to stimulate a neuron?

texts: Extracellular stimulation of neural tissue is done using electrode. Amount of current determines neurons how far from the electrode will be excited. How much current is required to stimulate the neuron in immediate vicinity? Such information is not available on internet.


texts: Small skull found in Alberta, Canada. Do not know the region. Skull is about 17 mm in length. Trying to identify the species, narrowed it down to most like a species of vole but can't figure out which one. Below are pictures of the teeth under a dissecting microscope that we were using to ID, upper jaw and then lower jaw respectively.


texts: Is cell wall and cytoplasm an organelle?

texts:
So cell wall is an organelle?
Whereas, it is not a membrane-closed organelle?

Cytoplasm is an organelle?
Whereas, it is not a membrane-closed organelle?


texts: Pseudomonas aeruginosa biofilms grows stronger after 95 % ethanol treatment

texts: I used 95 % ethanol to disinfect Pseudomonas aeruginosa biofilms from titanium discs and compared it to disinfection with water and hydrogen peroxide. The strange thing was that when examining in SEM, roughly ten times more bacteria was present in the ethanol treated samples than the water treated samples hydrogen peroxide treated samples showed no bacteria. Metabolic activity assay showed however more bacterial activity from the water treated samples than the ethanol treated, hydrogen peroxide showed least. Anyone have any theory why ethanol seamed to increase the bacterial biofilm compared to water? Ethanol are regarded as an effective disinfectant on bacteria.


texts: What is the most recent non-primate ancestors of humans?

texts: If we go down the evolutionary tree of humans, (Homo sapiens, Homo erectus, ...), what will be the first non-primate ancestors?


texts: Reasons for strange heart rate graph following exercise (line going up and down)?

texts:
Following a 2 minute general jumping and movement exercise designed to involve the entire body, the pulse was taken every minute for ten seconds. Strangely, the graph appears to jump up and down, for which I have little understanding why.

The pulse was measured simply and crudely with the traditional "fingers on the wrist" method.

If it is not clear, time is on the x axis and no. of heartbeats per minute on the y.

Thanks in advance


texts: What are the known natural biochemical reasons for a dead human's body not fully decaying?

texts:
What are the known natural biochemical reasons for a dead human's body not fully decaying (decomposing)?

EDIT:
I am interested in a scientific explanation of those cases, in which human body would not fully decay, for example, some parts of skin and hair would still be there, and I am not talking about such cases like hand-made mummification (like, say, those Pharaoh's mummies in Egypt).


texts: Did early 20th century researchers state why they used E. coli as a model organism?

texts:
I am investigating the early uses of E. coli as a model organism. Sadly, many early 20th century papers are not in English. In those that are, I have been unable to find explicit statements as to why a researcher chose to use E. coli as a model organism.

Does anyone know of early literature in which this reasoning is stated? I imagine that prior to the widespread use of E. coli, scientists would have had to argue why they chose to use it to investigate biological phenomena not limited to this bacterium alone.


texts: Our eyes are spherical, our retina is circular, but still our eyes can see more in the horizontal direction than in vertical direction. Why is it so, why is the preferred aspect ratio not square?


texts: Does the mesoderm evolve from the ectoderm or the endoderm?

texts:
I know the embryos of most animals develop into 3 germ layers. However primitive animals, such as Cnidarians, only have 2 germ layers - they lack a mesoderm. Therefore the 3rd germ layer must have evolved from cells which originally differentiate to one of the two more basal germ layers.

So my question is - does the mesoderm evolve from the ectoderm or the endoderm? Meaning, during embryogenesis, which cell type is the first to differentiate from the other two - the ectoderm or the endoderm?


texts: Why are there so many sex determining systems in animals

texts:
There are several sex determining systems in animals.

In mammals XY = male(except in rare cases where SRY crosses with genes on the X so that it is the reverse) and XX = female.

In  some birds it is just the opposite. That is XY(actually ZW) = fertile female and XX(actually ZZ) = fertile male.

In  some reptiles it is determined by temperature and has no genetic determination.

In lots of insects there is XX = female and X0 = male. This is usually accompanied by males being haploid and females being diploid like it is in bees.

In some insects and reptiles there is also the ZW/ZZ system but they are not dependent on it. In other words ZZW in some insects and reptiles can give rise to either sex but there is no temperature determination either.

Why are there so many sex determining systems? Why did animals evolve to not all have the familiar XY system? It must be so confusing as to which species has which sex determining system when biologists are trying to determine the gender of an animal.


texts: From the moment we learn to communicate, we always get told, whether by our parents, or our teachers, or by anyone else, to avoid the cold, or to put a jacket on to avoid catching a cold, to dry our hair before we go outside, because we'll get sick otherwise, so on and so forth. I also was diagnosed with a pneumonia last year, while in Switzerland under chilly conditions ($-20^◦\text{C}$). This made me wonder, why does the cold make us sick? It doesn't seem logical to me that a viral infection like the common cold, or a viral/bacterial infection such as a pneumonia is more prevalent when it's colder outside. I always figured it was because our bodies are less 'effective' under cold temperatures, but this seems lacking to me. Can anyone explain?


texts: Validated Protein-Protein interaction database for cancer

texts: I need to use validated PPI data in my research. Is there any database of such validated (like Mass Spectrometry) database for cancer?


texts:
I recently found an article talking about the colors of bird feathers. https://www.smithsonianmag.com/science-nature/why-are-some-feathers-blue-100492890/
Apparently, unlike other colors, where pigmentation is at fault, blue feathers are actually blue thanks to their unique structure. According to the article, when the feathers grow, they form air pockets, which then form a pattern that just so happens to cancel out the red and yellow wavelenghts, leaving us with blue.

Now, of course, all feathers have the ability to trap air. It's what makes them such excellent insulators, as air conducts heat very poorly. Bonus points if the air is contained in very small cells, as that increases a materials insulation qualities. It's for the very same reason we also use foam for this. Now my question is: As the blue feathers contain miniature air pockets to give them their color, would that make them, in essence, better heat insulators than the ones of other colors, or do all feathers have such pockets, and the blue birds just so happen to be arranged differently, without actually changing any insulation capabilities?


texts: Redox potentials in photosynthesis light dependent stage

texts:
In my lecture notes, it states

...there is a significant thermodynamic problem due to the respective redox potentials of the half reactions:
H2O<--> 1/2 O2 + 2H+ +2e-      pE=+0.82V
NADP+ +2H+ +2e- <--> NADPH +H+      pE=-0.32V

Could someone please explain what the 'pE' is? I thought it would be just ordinary redox potential, however the redox potential for water is apparently +1.23V not 0.82V. I cannot find anywhere a source stating the figures given above or what they mean (I have also consulted Biochemisty, Stryer et al)
Could it have something to do with this being the potential in the conditions present in a typical chloroplast as opposed to standard conditions?


texts: I'm confused about how organelles communicate with each other. I understand signaling between cells and the whole transcription and translation of DNA process. However, how does a motor protein know the destination of its package? How does a lysosome know when to break down a worn out organelle? How does the cell distribute ATP to the organelles where it's needed (how does it figure out where the ATP is needed?)?


texts:
I recently read up that people with NADPH oxidase deficiency (Chronic granulomatous disease CGD) have a tendency to be infected by Catalase positive organisms. NADPH oxidase helps produce the $H_2O_2$ via superoxide that is required by other enzymes to kill the bacteria.

Case 1: In the phagoloysozome, when there is a deficiency of NADPH oxidase, catalase positives can clear off the $H_2O_2$ they produce, thereby stopping production of free radicals via Fenton and myeloperoxidase. The bacteria survives and hence causes symptomatic infection in CGD patients.

Case 2: On the other hand, since catalase negative organisms can't clear off the $H_2O_2$ they produce, they remain susceptible to the free radicals produced by other enzymes like Myeloperoxidase and Fenton reaction, which would still kill the bacteria. In short, the bacteria 'lend' the $H_2O_2$ which feeds into these reactions leading to its own death. Hence, CGD patients can fight off catalase negative organisms.

My question is, why do the bacteria produce $H_2O_2$ in the first place? Is it produced only by aerobic organisms? If so, why would there be organisms that produce $H_2O_2$ and still not have a catalase (as had happened in case 2)? Isn't $H_2O_2$ is harmful even in the absence of free radical producing enzymes since the Fenton reaction is a non-enzymatic reaction?


texts: Goats are so fearless but sheep are not. Is there any genetic difference responsible?

texts: As you see in the picture goats (not only wild goats) are so fearless, but I never saw any sheep do this. What is the source of this difference in behavior?


texts: How do emus/ostriches/rheas have their upper leg connected to the rest of their body?

texts:
I'm working on a model for educational graphics of an emu in conjunction with other information, but there aren't a lot of great reference images. The thing that's most unclear is how the upper leg around the femur is connected to the rest of the body because it's always obscured by feathers.

Mainly, is the leg connected to the rest of the area around the hip only half way through the femur, at the distal joint of the femur, or past the distal joint of the femur to the tibia? Elephants seem to have the third option, while horses seem to have the second option, and wolves seem to have the first option, so there are many possibilities without a clear generalization.
Below are the three options with the red indicating how far up the body the leg is connected to the skin of the hip area.


texts: Is Hematoxylin/Eosin stained tissue used for cancer scoring?

texts:
I am an engineering student working for the first time in breast cancer field. I am trying to learn breast cancer scoring (for example Allred score). I have come across 2 types of images:
First (let be A):

Second (let be B):

Images are from the VitroVivo site.
My confusion:
For breast cancer scoring, is image A used?
What I think I understand: In cancer scoring (in breast), we are trying to find a score. For example in image B we have immunopositive (brown) nuclei and immunonegative (blue) nuclei and the ratio of brown to total is an indicator. This brown nuclei can be Ki67, HER2, Estrogen, Progesterone protein/antigen. But in H&E stained images, nuclei are separated from cytoplasm. There are no positive/negative nuclei, only one type of nucleus. So, is there any way H&E stained tissues are used for scoring?


texts:
As far as I know, in developed countries protection suits used by people who treat patients with Ebola are disposed of after a shift.

From a rather ambitious costume last year, I still have a hazmat suit like this one and this full-face gas mask.

More out of curiosity than out of real concern, I was wondering whether it would be possible to use this equipment in a potential outbreak of the virus. My greatest concern would be reusing the suit, as it might not be safe after the first use.

Is there a way to disinfect the suit and mask with publicly available chemicals? For example, I could imagine a friend spraying me with a solution of chlorine. Would that be feasible and make wearing the suit reduce the risk of an infection?


texts: What chemicals will kill P1 Phage but not E. coli?

texts: I'm working with E. coli and P1 Phage. I'm wondering if there is some chemical agent that will kill or disable P1 but leave E. coli untouched? It is not enough to just prevent infection. It must destroy the Phage.


texts: Most school books still say that recapitulation is an evidence of evolution but as far as I know it has been proved wrong so why is it being still taught? Has it got any sort of relevance?


texts: Could anyone please identify this flower/plant found on the semi-shaded banks of a river in East Ireland? It was located near Japanese Knotweed and looks quite similar to this.


texts: Found this spider in my bathroom on the wall by the door. Near Houston, TX.


texts: How does the intracellular accumulation of cyclic AMP cause edema in case of anthrax?

texts: Edema factor is adenyl cyclase which is activated only inside the target cell. It leads to intracellular accumulation of cyclic AMP resulting in edema. How?


texts: Does sleep duration vary for animals based on time of the year?

texts:
I'm interested in the sleep patterns of wild animals, that still use sun for controlling their biological clock.

Animals entrain their biological clock to the day/night cycle using light as the entrainment signal. The biological clock follows the day/night cycle: dim light initiates melatonin secretion, while bright morning light stops melatonin production. Melatonin is involved in sleep regulation

Here, I have plotted the day duration over the course of the year for Northeast US, around Washington DC.

My question is given the day duration plot below, would the total sleep duration for wild animals vary over the course of the year?

In other words, would animals sleep longer in the winter time and shorter in the summer time?


texts: Why AZT is selective towards HIV and doesn't impair human DNA replication?

texts:
I've found this article, which is a very old one (from the time when nucleoside analogs where researched as a possible way to prevent replication of virus genetic material, before the HIV epidemics).
In the last page, the authors suggest that cellular repair enzymes could remove azidothymidine (AZT, zidovudine) from cellular DNA if it's incorporated, but viruses' polymerases lack this ability.
As it's an old article, I would like to know if this hypothesis was confirmed. As both azidothymidine and thymidine can form normal base pairings, how could human enzymes detect an azidothymidine was incorporated?

If someone is not familiar with AZT mechanism: basically, it's an analog of thymidine which has an azide group instead of 3'-OH

It can be phosphorylated by cell kinases and incorporated to the growing DNA chain; however, this will stop the polymerization because it depends on free 3'-OH. The natural question which follows is: why wouldn't AZT also block the replication of human cells' DNA?


texts: If our skin is burned by the sun what causes the red color of the skin?

texts:
Mostly it is not a good sign we are burned because too much UV light has damaged our skin and increases skincancers.

But the red color we get after a few ours, what is the exact cause of it and why is it red? Is that our blood we see or other changes in skincells or our immunesystem reacting?

And why does it takes a while before it gets red?


texts:
In genbank (ftp://ftp.ncbi.nlm.nih.gov/genomes/archive/old_refseq/Fungi/Saccharomyces_cerevisiae_uid128/) there are an archive .frn (nucleotide sequences of structural RNAs in fasta format), and  I want to know the differences between structural RNAs and genes.
Are the nucleotide sequences of structural RNAs a coding region?

My goal is separate the coding region from the non coding region of a given complete genome.

I'm physicist so, I apologize if my question is pretty simple.


texts: Confusion regarding the ventricle system in the brain

texts:
I have a hard time finding out a small detail about the ventricle system.

As the CSF flows into the 4th ventricle, there's a small foramen in the lateral aspect, as well as an open space bounded by the medulla and cerebellum.

Do both these lead the same place? Is the space under the arachnoid matter only accessed through the small foramen, whereas the space between the medulla and cerebellum leads into the spinal column?


texts: What is the difference between a paralog and an isoform?

texts:
I am reading a journal paper about the protein kinase GSK3 and I have come across the following statement:

Although commonly referred to as isoforms, GSK3α and GSK3β are
actually paralogs, homologous proteins derived from different genes.

I am not sure what the difference is between an isoform and a paralog. I have Googled both definitions and paralogs refer to 'genes that derive from the same ancestral genes'.
Whereas isoforms refer to 'any of two or more functionally similar proteins that have a similar but not identical amino acid sequence and are either encoded by different genes or by RNA transcripts from the same gene which have had different exons removed'
These definitions seem quite similar to me so I was wondering if there are any significant differences between paralogs and isoforms? Any insights are appreciated.


texts: Do cows produce more milk than it is required for their calves? It seems like cows are able to provide milk all the time (all year around). Is it so? Or do they, like other mammals, produce milk only in ammounts requeired by their offspring?


texts: Atlas from human brain structures to 3D coordinates?

texts:
I would like to visualize specific human brain structures in the three dimensional space and compute specific geometric properties of these brain structures (size, centroid, etc).

Therefore, I am looking for an atlas that maps human brain structures to 3D coordinates (in Talairach or MNI coordinates).

I saw online a lot of websites allowing the inverse mapping, which is from coordinates to brain structures. So I know that this data should be somewhere but I was not able to find it.

Any lead would be greatly appreciated.


texts: I observed many beetles like this in Pune/India in the beginning of rainy season. It was dark green in color with white spots and not too much shiny like many other beetles. Size is about 2cm to 3cm.


texts: Regarding inherited fertility in animals

texts: If an animal is fertile does it follow that both its parents of the same species (not necessarily the same species of the offspring)? Was it Mayer who said a fertile male and fertile female of two different species, if they 'reproduce' and the offspring survives it won't be fertile. Reproductive isolation I think this is called. So if an animal is fertile then both its parents should be of the same species, right?


texts: I'm concerned about the safety and mechanism of RF cautery. The frequency of the radio waves used is 4Mhz so normally there should not be any DNA damage BUT the thing you read everywhere is that only UV, X-rays and Gamma rays have enough energy to pop an electron from the orbit. Can't the same energy be reached with radio waves (higher amplitude instead of higher frequency). After all the RF cautery evaporates the cells why wouldn't it damage the DNA of the remaining cells?


texts:
Recently I took this shot of a 'pack' of ants moving towards some destination, and I was wondering, is this normal? Aren't ant scouts lone wolfs, and when a viable source of food is found near the ant colony, the worker ants form a trail to facilitate transport? If so(I'm poorly versed with biology as such, being an electrical engineering student), what purpose could this formation serve, my opinion being bent on supposed predator protection. This is not the only one I've noticed, but it is new to me, and a quick google search without any technical terms to feed it, yielded nothing substantial. This is the monsoon season here in India, if it is of any consequence to this peculiar behaviour.

I'd love to found out more about this(tag edits would be helpful), thank you :D


texts: Identification of fuzzy insect in Pennsylvania

texts: I live in south eastern Pennsylvania, USA. About a month ago I came across this very peculiar insect. Its body was about an inch long, it was fuzzy, and it had a long proboscis(?) and long orange legs.  I've been wondering about it ever since. Can anyone identify it?


texts: What is the largest animal that has no hard parts?

texts: Some examples of "hard" animal parts are bones, cartilage, and exoskeletons. What animal has the most mass while being completely "soft". I don't think it's the colossal squid, since it has a hard beak and cartilage in their mantle. My guess is the heaviest jellyfish.


texts: Blocking buffer for actin and fetuin-b in western blot

texts: I have been working on western blots for about a month now using actin and fetuin-b primary antibodies to no avail. My background is always high and I only had one good result. I want to know if there is a certain blocking buffer I should use instead of 5% milk with my membranes to get a better result.


texts:
A greyish bird, with brown head and relatively long, pointy beak.
Size comparable to mallard.
Spotted in central Poland, on small, artificial pond, populated by mallards and Eurasian coots.
Photo has been taken today (late September).

I'd be grateful for any information that could be used to identify this bird.


texts: Difference between micro RNA and short-interfering RNA and CRISPR Cas 9 system?

texts:
I read this article https://www.quantamagazine.org/20150206-crispr-dna-editor-bacteria/ and am slightly puzzled as to why the CRISPR/Cas 9 system is seen as being so revolutionary. It seems like the very same thing that micro RNA and short interfering RNA does- cleaves synthesised mRNA strands by attaching to the complementary part of the mmRNA strand, and the restrictive enzymes combine to this RNA and cleave it. I don't see how the CRISPR system is any different or better...

Thank you in advance :)

EDIT: Also, does anyone know whether Cas 9 cuts both DNA strands at the same place, or whether it leaves 'sticky ends'? Thank you.


texts:
Is it possible to restart the whole human species with less than 10 individual.
let say that the whole human species was wipe out of the surface of the earth by a catastrophe only 8 different couple survive the catastrophe could they restart the human species?