texts: GABA in plants (article about its mechanism)

texts:
I am studing to plant physiology exam and i cross over the statment about GABA in plants.

It said that level of GABA increasing my thermal shock. But mechanism of effect on plants is unknown.

Can anybody give me a tipe about proper article about it?


texts: Genotype of children conceived after stem cell transplant?

texts: If you have sickle cell disease and have a succesful stem cell or bone marrow transplant, your blood type changes to AA. But what about your future children? Do your sperm or egg cells continue to express the SS genotype or do they become AA as well?


texts: Is there a survey on whether people have gained or lost weight as a consequence of lockdown?

texts:
I am not sure if this is the right forum for asking such a question. Moderators can of course close it if it isn't and please migrate it to relevant site.
Is there a survey/study that statistically checks whether people have gained or lost weight as a consequence of lockdown?
Of course, it would be a complicated as there would be a need for number of controls such as age, usual changes in lifestyle of subjects (independent of lockdown), etc.


texts: Can an organism obtaining a part of its genome via horizontal gene transfer be called a "hybrid"?

texts:
Wikipedia definition of "hybrid" offers many competing definitions. But most seem to be centered on sexual-reproduction gene transfer.

Is there an official (in a textbook or widely accepted peer reviewed work) definition of a "hybrid"/"hybridization" that would clearly include ANY genetic mixing, most specifically obtaining genes via horizontal gene transfer?

If not, is it specifically because "hybrid" requires sexual reproduction, or merely because it requires a certain minimal amount of inherited genetic material from both sides, and horisontal genetic transfer in practice involves significantly less genetic material being inherited?


texts: How is randomness of the branch migration process ensured?

texts: Branch migration (part of genetic recombination) is a random process. It looks like Ruv-ABC proteins are mainly responsible for this process, but how is randomness ensured? After all, it can only be a quasi-random process - i.e. molecules don't behave randomly. Is it thermal motion perhaps?


texts: When did the most recent common ancestor of all living domestic dogs live?

texts: Wikipedia provides a very detailed page on the origins of the domestic dog, but this fact does not seem to be present there. Google searches for terms such as "most recent common ancestor (MRCA) of dogs" didn't reveal any authoritative sources.


texts: What were the mammal ancestors like 65 million years ago?

texts: What we know about our mammal ancestors that were alive (and survived) at the extinction event 65 million years ago?


texts: I was walking on the beach in New Jersey (U.S.), at about 40 degrees longitude, and found this bone. It's not a fish. The long process in the front is interesting. It is likely a C2 vertebra. I looked on the web, but could not find anything aquatic that it might match. Certainly not a dolphin. It is 2 inches long (50 mm), and 2.5 inches high and wide (64 mm). I guess it need not be aquatic, and New York City (20 miles North of here) used to dump garbage in the ocean. It looks old. Can you help me identify it?


texts: Why do Alu repeats form secondary structures?

texts:
I've been doing a lot of research on Alu repeats and how they mediate the gene expression. I read the following article "Useful junk: Alu RNAs in the human transcriptome".

And it says that alu repeats embedded in 5'UTR makes stable secondary structure that prevents the assembly of ribosomal subunits, thus blocking the process of translation. I've been reading various articles to find out why Alu repeats form this secondary structure and why only in the 5'UTR and not in the 3'UTR. But haven't been able to find an answer.


texts: I am experimenting with grafting multiple heartleaf philodendrons(philodendron cordatum) to the root of an oak tree(quercus). If the grafting is successful, the next step is to cut the root from the trunk, cap it, and place it in a long rectangular potter. The experiment to follow this will be to sustain the tree root with the philodendrons, and symbiotically use the philodendrons to sustain the tree root. Does anyone have experience in this type of experimental research and advice to provide?


texts: Human bone density and Brown Bear bone density?

texts:
It is stated on this website that the density of a Grizzly bear bone is ten times our own. And since I am not into biology at all, I am confused as I don't understand the meaning of bone density here.

I know what the "bone mineral density" term means, and I know it is measured in $g/cm^2$, but there is also the "physical" density term which is the mass by volume and it's measured in $g/cm^3$.

Now, what does it mean when we say that an animal has a bone that is 10 times more dense than ours ? Does it mean that the bone weighs 10 times more for the same size (or volume) ? Or does it mean that it has 10 times the amount of minerals and so it is somehow stronger ?


texts: Identify the pink mold infecting refrigerated lemons

texts:
I made lemon juice 6 month ago.

I just washed the lemon using brush and then cut them into pieces.
Then I put one layer of lemon in the bottle followed by one layer of
sugar
Again one layer of lemon and one layer of sugar.
Then I close the bottle and put it in the refrigerator.

When I opened it, I observed some pink colored mold on the lemon slices.

Can anyone can identify the mold or tell me how to identify it?

PS: in the 6 months, I never opened the bottle. The bottle was clean and I did not add water; just lemon and sugar.


texts: What is the difference in the electrical excitability between a "large diameter soma" and a "large diameter axon"

texts:
There are two stereotyped statements that I have seen during my coursework regarding electric properties of neurons:

Large diameter axons propagate action potentials more quickly than small diameter axons
Large motor neurons are the last motor neurons to be recruited

Separately, I have always understood these statements through the following lens:

Explanation for 1. (for arguments sake, lets talk about unmyelinated neurons...so, for example, a C-fiber with a small diameter and a C-fiber with a slightly larger diameter). The reason the larger diameter neuron will propagate its action potential more quickly is because, in a given cross section of the axon, there are more voltage gated sodium channels present along the circumference. Consequently, the speed with which the incoming sodium signal is generated is quicker. I am aware of "reduced longitudinal resistance" for larger axons, but I am purposely ignoring this...please continue reading.

Explanation for 2. Idealizing the soma of a neuron as a sphere, we know that capacitance increases with increasing radius (related to the distribution of charge along a 'longer' circumference). Consequently, for a large soma, the amount of charge required in order to observe a change in potential difference across the membrane is MORE than it would be for a smaller soma.

When treated individually, both of these statements are intuitively "okay". However, when I think of these two statements together, confusion arises:

A. Shouldn't the increased total number of ion channels observed in the larger diameter axon also be observed in the larger soma?

B. Shouldn't the capacitance increase observed in the larger soma also be observed in the larger unmyelinated axon?

If both of these statements are equivalently applicable in both cases, why do the two statements "1" and "2" seem fundamentally different?

The only rationale I can think is the following: The % of surface area occupied by ion channels on the soma membrane is significantly less than the % of surface area occupied by ion channels on the axon membrane. Consequently, the axon can offset its increased capacitance by the gain in additional ion channels. However, the soma cannot offset its increased capacitance because the % of ion channels occupying its surface is below this "capacitance offset" value.

Edit:

I have provided two pictures to help clarify my question:

As you can see from the above two images, the values in the two tables are the exact same. Summarizing, the larger soma and larger myelinated segment of axon both exhibit:

Less Longitudinal Resistance
Greater Capacitance
Greater Surface Area Available for Ion Channels

I have previously asked two separate questions:

Here_1: Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?

and

Here_2: Why do larger diameter myelinated axons have greater conduction velocities than small diameter myelinated axons?

The conclusions from the two questions were that larger somas take longer to depolarize and larger axons transmit electric signal more quickly.

Even though both 'entities' exhibit shared electrical properties, it appears as though the outcome of having these electrical properties is fundamentally different. In one case, the membrane is taking longer to depolarize...but in another case, the membrane is depolarizing quickly!

What am I missing that results in my perception that electrical properties are somehow being differently applied to the soma of a neuron and the axon of a neuron?

(Note that this question involves the myelinated section of the neuron so there is no need to talk about nodes of ranvier or any sort of "active" electric process)


texts:
The dorsal nerve cord of vertebrates is a hollow structure that develops into the nervous system. This embryonic tissue is hollow and I wonder what happens to this 'hollow' later?

Does it form the ventricles of brain?


texts: What would happen to the body if it suffered no injuries?

texts:
In this (super cute) animation: 'Jinxy Jenkins & Lucky Lou' (youtube), the girl, Lucky Lou, is shown to be so lucky, she seems to have never suffered an injury. This is, atleast, what I get the indication of at 1:26 when she looks at her hand in a mixture of confusion and awe.

And this got me thinking, what kind of applications would it have for a human body, to live to about 20-25 without having ANY injuries happen to it? And I mean NONE, not even muscle aches, scraping of hands or knees, no nothing.

I may be wrong in this, but I have perhaps been led to believe that when an injury occours, whilst the body repairs itself, it also goes through some steps to toughen the injured area.

Would the body be noticably more fragile, or would it have virtually no effect?


texts:
As I understand it, any gene on an exposed/unpacked region of a chromosome is continuously being expressed. Regulatory genes may increase or decrease the amount of protein synthesised due to its expression, but its expression is still fairly continuous.

Assuming I am correct, is there any regulatory framework by which genes are sequentially expressed. That is where the expression of one gene causes it to be turned off and another turned on?

For example, say some chromosome has genes A, B, and C. Is there a situation where gene A is expressed for some period, then gene B, and then gene C, but no more than one is ever expressed at once and they only are expressed in that order?

EDIT: I'll clarify that I don't expect genes which are suppressed to somehow still be accessible. Making them inaccessible is (as far as I know) how they are shut down. My point in mentioning how accessible genes are expressed is to highlight the uncontrolled nature of gene expression in relation to sequential gene expression and therefore to ask how the genetic machinery can get around this problem.


texts: Does methanol fixation deform cultured cells?

texts:
I use methanol fixation (@ -20⁰C for 10 minutes) when performing immunofluorescence assays on cultured cells. Generally speaking, this results in very good antibody staining. However, the cells tend to look markedly different than they did under phase contrast microscopy prior to fixation. This has my PI worried about how these images will be received by reviewers.

How does a methanol fixative work, and why does it cause a change in cell morphology? Are there parameters that can be adjusted to mitigate this effect?


texts: I'd like to add a cell penetrating peptide to my custom peptide (30aa). Can I just add it to the end of the peptide sequence or does it have to be positioned on an outward facing external chain?


texts: Why do people's hands get cold for the first half an hour and then suddenly they are warm when they are doing exercise outdoors in winter?

texts: When people do exercise outdoors in winter at temperatures less than zero degree celsius, their hands are quite cold and hurt for about half an hour. Then, there is a sudden rush of blood into the hands and they are warm afterwards, just as if they are indoors all along. Why does this happen and is there anything one can do to trigger the warmth faster?


texts:
How much penicillinase is needed to deactivate 125mg of amoxicillin?

Penicillinase in penase concentrate from CPC.
20,000 Levy Units/ml/min

I need IU of 125 mg of amoxicillin.

Please note that the problem is with finding the right parameters for amoxicillin, not penicillin G.

My goal is to test an amoxicillin product (i.e. it contains more than just amoxicillin) so the overall problem is more complex, I wanted to keep the question focused.

I would like to know the minimal amount of penase needed to deactivate 125mg of amoxicillin (that's the amount of amoxicillin in the product) in a reasonable amount of time, say 5 minutes. I want the minimal amount of penase because I am not sure what is its influence on bacterial growth, I am going to test that separately. Maybe I am going wrong about the whole problem?

I think that this paper could be helpful in general: Microbiological Applications of the Inactivation of Antibiotics and Other Antimicrobial Agents but it's behind a paywall and I can't access it at the moment. So far, I failed to find any other useful resources.


texts: Finding Regulatory Elements: How Have People Been Doing This?

texts:
First up, I am NOT asking about how to search for and match regulatory elements using a database. I'm asking about how people found what to search for and match in a genome, how they built those databases. My question is,

How did people identify regulatory proteins/nucleotide elements in the first place?

Did they first find the proteins we now call transcription factors and sigma factors, or did they tamper with the genome to find the regulatory parts and then traced them to the proteins?

Is there a book on the history of research gene regulation to recommend?

Also, I tried Googling. Every site recommended one database or the other. I would be grateful too if you could tell me what should I have searched for?

I am more interested in Prokaryotes, but answers on Eukaryotes would also be welcome.

Context: I'm a freshman doing research (yep. the experience is kinda crazy for me) and I'm interested in finding regulatory elements in Mycobacterium smegmatis and its phages.


texts: How much of human's behaviors and preference can be explained by evolution?

texts: I'm talking about things like the tendency to feel sleepy after eating, avoidance of excrements, general preference for sweet foods, etc. Do all those characteristics have biological or evolutionary basis?


texts: I'm talking about CRISPR system. I know the crRNA is transcribed from the palindromic repeat and the "spacer" but I don't know where the tracrRNA comes from.


texts: Do death rate and birth rate become equal at replacement fertility rate?

texts:
A population transitions from stage 3 to stage 4 when the fertility rate reaches the population replacement level of 2.1.

My question is that if the population replacement level reached, shouldn't the net growth rate be zero? i.e., birth rate = death rate? But in the figure, in stage 4, birth rate > death rate and there is still a population increase.

How is this so?


texts: What is the oval shaped bone in the heads of some fishes?

texts:
I had a dish of fish and found 2 oval shaped nearly 1cm long bones in its head.What help does it do to the fish? what is its name?
I have clicked the picture myself .


texts: Why is the resonance frequency of a neuron defined by peak impedance?

texts:
I'm relatively new to the field of electrophysiology, so if anything is unclear or incorrect, please let me know.
One thing that continues to confuse me throughout my reading is the property of resonance frequency of a neuron.  Generally, I've seen resonance frequency defined as the frequency at which neurons respond best to inputs of injected current, which makes sense.  What does not make sense to me is why it has also been defined as the frequency at which peak impedance is observed because in circuit analysis, resonance frequency is the exact opposite (the value of frequency at which you have minimum impedance).  The definition for electronics is logical in my mind because that's also the value at which current is at a maximum (since the impedance is lowest).  I'm assuming that the relationship between impedance and resonance frequency is flipped in neurons because of another property I'm not considering (like driving force of ions, voltage-gated channels, etc.), but I'm genuinely curious what the reason is.  If anyone could be of assistance on this, I would greatly appreciate it.

EDIT WITH POTENTIAL RESOLUTION BY QUESTIONER:  I believe one of the pioneering texts discussing neuronal resonance was a Trends in Neurosciences paper by Hutcheon and Yarom (Volume 23, Issue 5, published in 2000).  However, after reviewing this text, I think I may finally understand the idea.  As described in the referenced article (which I would highly recommend), membrane properties of a neuron allow it to act like a band pass filter. A little more poking around the internet led me to the conclusion that it is specifically a parallel resonant band-pass filter (for a brief explanation, visit  http://www.allaboutcircuits.com/textbook/alternating-current/chpt-8/resonant-filters/).  I believe this might be the correct interpretation, but have left it as an open question because if there is something wrong in my interpretation, all you bright individuals out there can point out my mistakes or elaborate further on the concept!  Thank you!


texts: Evolution of sexually concordant genetic variation on the X-chromosome

texts:
It was theorised in 1984 that sexually antagonistic genetic (SA) variation should more easily evolve on the X-chromosome. This is partly because female beneficial/male deleterious mutations face less powerful selection against them; the X is in females twice as often as in males so mutations will persist up to the point where male cost is <2x the females gain. Furthermore, male beneficial/female deleterious recessive mutations (p) will always be expressed in males and, when rare, only very occasionally in females; if the frequency of p 0.1 then 1 in 10 males will express that trait and only 1 in 100 of the females.

It is therefore expected that the X-chromosome should become a hotspot for SA variation in comparison to the autosomes. A result would be increased persistence of genetic variation on the X- within sexually antagonistic loci. However, how would a sexually concordant (male & female beneficial, or male & female deleterious) fare in the X- compared to the autosomes? Just eyeballing it, it feels like the X- should be better able to select on recessive mutations because they are always expressed in males; removing deleterious and spreading beneficial mutations more rapidly. Should there then be less genetic variation on the X- than autosomes?


texts: Why in the Electron Transport Chain does PS2 go before PS1?


texts: Why WHO has not eliminated chicken pox like smallpox?

texts:
Chicken pox is a viral disease, so why then has the World Health Organization (WHO) not eliminated chicken pox like smallpox?

Smallpox still exists in labs.


texts: Can epistaxis or nosebleeds be a cause of death?


texts: Additive genetic variance components from LMER in R

texts:
I've set up some dummy data in R which makes 40 genetically related lines, they are all siblings within a line so are genetically related by a factor of ½ thus additive genetic variance should be twice the variance explained by line. For the lines there are 200 individuals being measured, for three characters/traits. The first trait has low phenotypic variance, the second has high environmental variance, and the third has high genetic variance.

rm(list=ls())
re = 200 # replicate individuals per line
li = 40  # lines

# setup
set.seed(5)
data = data.frame(rep(1:li, each = re))
colnames(data)="Line"
library(nlme)
library(lme4)
par(mfrow=c(1,3))

# trait 1: little variance (Va or Ve)
data$Trait = rnorm(li*re,10,1)
boxplot(data$Trait~data$Line, ylim=c(0,20), main = expression("Low V"[A]*"& Low V"[E]))
var1 = var(data$Trait); mean1 = mean(data$Trait); m1 = lmer(data$Trait ~ (1|data$Line))

# trait 2: high enivronmental variance, little Va
data$Trait = rnorm(li*re,10,1); data$Trait = data$Trait + rnorm(re*li,0,3)
boxplot(data$Trait~data$Line, ylim=c(0,20),main = expression("Low V"[A]*"& High V"[E]))
var2 = var(data$Trait); mean2 = mean(data$Trait); m2 = lmer(data$Trait ~ (1|data$Line))

# trait 3: high additive genetic variance, little Ve
data$Trait = rnorm(li*re,10,1); data$Trait = data$Trait+rep(rnorm(li,0,3),each=re)
boxplot(data$Trait~data$Line, ylim=c(0,20), main = expression("High V"[A]*"& Low V"[E]))
var3 = var(data$Trait); mean3 = mean(data$Trait); m3 = lmer(data$Trait ~ (1|data$Line))

Plots of the three traits,

Then to estimate additive variance ($V_A$) I extract the line variance ($V_L$) from the lmer model and double it,

# line variances (variance in additive effect of each haploid genome)
m1_line = unlist(VarCorr(m1))[[1]];
m2_line = unlist(VarCorr(m2))[[1]];
m3_line = unlist(VarCorr(m3))[[1]]

# additive variance (double the line variance because it is a hemiclone)
m1_add = 2*m1_line;
m2_add = 2*m2_line;
m3_add = 2*m3_line

Residual variances should be (assuming perfect experimental design, no measurement error etc.) the estimate of environmental variance ($V_E$) and phenotypic variance ($V_P$) should be the sum of $V_L$ and $V_E$,

# residual variance
m1_res = attr(VarCorr(m1), "sc")^2
m2_res = attr(VarCorr(m2), "sc")^2
m3_res = attr(VarCorr(m3), "sc")^2

# phenotypic variance
m1_phe = m1_line + m1_res
m2_phe = m2_line + m2_res
m3_phe = m3_line + m3_res

Heritability is additive variance divided by the phenotypic variance

$h^2 = V_A / V_P$

But I think it is correct in this case to use line variance rather than additive variance (if someone could explain in an answer that would be useful), so I've done,

# heritability (line/ (line+ residual))
m1_h2 = m1_line/ m1_phe
m2_h2 = m2_line/ m2_phe
m3_h2 = m3_line/ m3_phe
m1_h2; m2_h2; m3_h2

My question(s):

Is it appropriate to use the lmer function in R to extract variance components in this manner?

Have I calculated $V_A$, $V_E$, $V_P$, $h^2$ correctly? I think $V_A$ and $V_E$ are correct, $V_P$ could perhaps be the sum of $V_A$ and $V_E$ rather than $V_L$, and subsequently $h^2$ may be $V_A/V_P$.


texts: Is hypoxia/anoxia the ultimate cause of death?

texts:
I know there are different causes of death for humans like heart disease, cancer, stroke, injury and so on, but i was thinking if in every case in the last instance death is due to hypoxia/anoxia.

Am i missing other mechanisms ?

What i'm searching are the last mechanism that cause the organism to collapse and die.

E.g. (non detailed just an example)
In the case of heart disease, a plaque could lead to the block of a myocardial artery followed by local hypoxia/anoxya that kills the heart tissue followed by cardiac arrest and death by general anoxia.


texts: What proportion of salt in water would make it not dehydrate nor hydrate someone?

texts: Drinking sea water can be deadly as it contains too much salt, basically de-hydrating the body. Normal tap water contains little salt and is good for re-hydration. My question: How much salt needs to be dissolved in water such that it does not hydrate nor de-hydrate? For instance, would a physiologic saline solution (9 grams of salt per liter of water) meet this criterion?


texts: How loud a sound would need to be to wake someone up?

texts:
I have been researching about this and it looks like the term would be auditory arousal threshold. Imagine you fall asleep while listening to music with earbuds. Out of a sudden, the device starts playing really loud music (let´s say 40 dB higher compared to what you were listening). This sound would be quite loud that it would damage your ears.
My question is, is there any study showing which would be the minimum dB level of a sound that would make you wake up (and, well, remove the earbuds)?
I would assume this would depend on the frequency of the signals as well. But, what about the age of the person?


texts: Why do NK cells not destroy bacteria, even though bacteria don't have MHC-I?

texts:
Part of the function of NK cells is to destroy cells that are unable to bind their KIR receptors. Or in other words, cells that don't express MHC class I. This is why they can kill MHC supressed infected- or tumor cells, which other immune cells can't.

However bacteria also don't express MHC-I. Yet NK cells are said to have very limited influence one microbial infections. I do not understand why NK cells do not degranulate (kill) bacteria upon finding that they do not have the MHC-I receptor complex.

Could someone elaborate this?


texts:
As the title says, are all cells organisms? Why or why not?

As I understand, not every cell is an organism because some of them -those which aren't organism- require the rest of the organism to live. But arguing with someone about that, he says that, for that matter, every cell needs of others to live in some way or another, or that they can be kept alive and sometimes reproduce in a petri dish, without the need of the organism. So every cell, he says, even those which constitute larger organisms are organisms in themselves. I tell him that saying every cell is an organism is awkward, that would imply that every multi-cellular organism is really a colony, rather than an organism.

Is this only a philosophical question or can we say for sure, for example, that an epidermal stem cell or a lymphocyte are not organisms?


texts: Is a sequential double transformation acceptable?

texts: Standard protocol states having two compatible vectors being transformed simultaneously during the same procedure. I've come across a situation in which transforming one vector, obtaining results, and then transforming the other is preferable. Is there any reason to think that this wouldn't work? Do I risk losing my first vector upon transformation of the second?


texts: We inserted an insulin gene from human into bacteria. Will translation of the gene (protein formation) occur in bacteria? If translation occurs then why does it occurs, give a reason for this?


texts: What are evolutionary implications of contraception and reduced childhood mortality rates worldwide?

texts:
I've heard the following idea this morning: Before the introduction of contraception, humans conceived quite a lot of babies (there was little to do to avoid that), but the population was kept in check by very high childhood mortality rates. This mortality rate ensured that only the fittest survived.

The idea seems common sense, but I decided to investigate if this is really true. I know that for evolution, even 2000 years should be an instant.

I did some research, for example the worst childhood mortality rate currently in the world is around 17.5%, which is still about half of what it was in "developed" countries during the 1700s, according to the table below. But looking at the wikipedia map of childhood mortality, it seems that a baby nowadays has only around 1-3% chance of dying before adulthood, because even the weakest baby can be kept on life support long enough for the danger to pass.

What are the implications of reducing childhood mortality rates worldwide on human evolution? Maybe evolution is a wrong term to use here. Would it be fitness as species? I'm particularly interested in how this relates to developmental defects and genetic disorders. Is there any evidence that people who lived in a world without contraception and with high childhood mortality rate were more physically or mentally fit?

Here's an paper that deals with the subject and the table is from the paper below:

IS CHILD DEATH THE CRUCIBLE OF HUMAN
EVOLUTION?


texts: Is there any small animal that can jump over a meter high/long?

texts: By small, let's say less than 5 cm body length. I always thought that grasshoppers were the highest absolute jumpers in this class but the highest jump according to this article is 0.7 m...


texts: Biosphere that simulates sun and moon shifts

texts:
Is there an enclosed biosphere that artificially simulates the movement of the sun and moon at increased intervals?

It is known that the sun and moon alter plant movements therefore I was wondering how far experimentation has gone.  Ideally I am wondering if they have experimented with different speeds of the moon and sun rotation and how it effects plant(and possibly other animal behavior ideas) growth.


texts: What is the distribution of the number of heterozygotes in finite populations?

texts:
Consider a bi-allelic locus with alleles A and a. We denote the frequency of the A allele by $p$. Assuming absence of selection and panmixia, the expected number of heterozygotes is $2p(1-p)N$, where $N$ is the population size. We can also calculate the expected number of AA and aa individuals.

What is the joint probability distribution of the number of AA, Aa and aa individuals?


texts:
I overheard a rather heated argument about whether or not animal cells have vacuoles.

One person said that they do, but they're much smaller than vacuoles in plant cells.

The other person said they don't. While there is something there that acts similar to a vacuole, it's slightly different. The person also noted that the only websites that say that something as a vacuole aren't credible sites (ie. not University sites, etc...)

I'm really curious as to which it is: Do animal cells have vacuoles or not?


texts: Does a top heavy population grow, decline or stabilize?

texts:
Imagine a population that has a larger proportion of older individuals than younger ones, what could possible happen to it in the future?

I am guessing that if the older individuals reproduce, the population will increase but as the older generation grow older they would eventually perish again decreasing the population. As they form the larger proportion, the net population would eventually grow but decline, but would the population then begin to stabilize or continue declining?


texts: What's the lowest temperature a tardigrade can remain active at?

texts:
There's a lot of information floating around the net about how tough they are & what they can survive, like "We now know that some tardigrades can tolerate being frozen to -272.8 °C".

But any details on the environmental ranges they can actually be active in rather than what extremes they can survive in one or other of their various states of metabolic suspension seem entirely absent for the casual (& not so casual, I've spent hours looking for these details) surfer.

So does anyone out there know what the temperature range of an active (rather than dormant) tardigrade is, with specific reference to the lower end of the scale.


texts: Like size and colour constancy, why does the brain not maintain focus constancy?

texts:
I have progressive myopia. I grew up with perfectly normal eyes but slowly started getting myopic.

The thing is, my brain knows (or should know) what the world looks like -- it knows that far away objects do not suddenly blur. So when the input from the retina changes, why doesn't the brain correct it in perception?

I'm assuming here that this should work by the same principles as size and colour constancy. In both cases the input from the retina is different but the brain doesn't perceive it as an actual change in size or colour.


texts: Last-ditch efforts to maintain thermal homeostasis

texts:
I was in the gym's steam-room today and a thought occurred to me: have I truly thwarted all possible mechanisms for maintaining thermal homeostasis?

There's sweating, which is thwarted because the steam-room's atmosphere is as close to 100% humidity as possible, so there's almost no evaporative cooling.

There's convection, which is thwarted because the ambient temperature is above normal body temperature.

And I can't get rid of heat by exhaling, because every lungful of air I inhale is already above normal body temperature.

I think that, eventually, I should go into hyperthermia, but beside the above, are there any other last-ditch attempts to lower core temperature that my body could take?


texts: Do ginko trees grow well in Eastern North America (specifically Ontario,Canada)

texts:
I have recently noticed many Ginko (Ginko biloba) saplings planted in my Eastern Ontario city (in Canada), and they are looking a bit sickly, with yellow leaves.
They seem to be a popular choice in new developments, but I didn't think they grew well in the region (which is in Hardiness Zone 5).  Could the yellowing leaves just be poor management, or are the poorly suited to the region?

Wikipedia tells me that although these trees are native to China, they have been cultivated in North America for 200 years.


texts: Could the protein dystrophin be artificially synthesised?

texts:
Could the protein dystrophin be artificially synthesised and if so could patients with DMD (Duchenne Muscular Dystrophy) benefit from it?

//Now I don't have much scientific background other than a high school biology qualification

I met someone the other day the same age as me who suffers from DMD, so I did some research and curiosity led to this question.

Sorry if I used the wrong tags or/and this question isn't allowed. \


texts:
Recently, I reviewed the different levels of chromatin structure. The primary level is nucleosomes, where DNA is bound to histones, and has structural similarity to "beads on a string." The secondary level is a 30nm fiber, and the tertiary level is formed by radially looping the fibers.

I've also been learning about the histone code and how different modifications to the core histones relate to transcriptional regulation. Are these modifications the primary regulation mechanism for chromatin structure? In other words, does chromatin assume the most compact structure possible until histone modifications are made to enable transcription? Or have other regulatory mechanisms unrelated to transcription been discovered and characterized?


texts: Empty room, Room full with stuffs & Auditory adaptation to reflection of sounds

texts:
Background

When a room is full with stuffs like furniture, electronic utilities, books etc. it's hard to hear reflections of sounds made by us (talking, playing an instrument, sound from falling objects).

But, when the room is empty we quite easily hear the reflections of sound which is according to physics perfectly legit.

However, what seems interesting to me that when we suddenly empty a room with stuffs, the change in hearing reflection of sounds has a great impact on our ear. I personally experienced  this phenomenon several times while emptying a room for cleaning and other purposes.

Question

Is it because of the sudden nature of the phenomenon described above, the phenomenon seems to have a greater impact on our ears?
What would happen if we try to get used to the empty room environment? Would sensory adaptation slowly diminishes our sensibility towards reflection?


texts: Are there solitary animals communicating with themselves?

texts:
I can imagine 3 different kinds of communication between individuals:

Communication between individuals of the same species.
Communication between an individual and another from a different species.
Communication between an individual and the same individual at a different time, i. e. some individual "taking notes" or "marks" for later use.

My question is whether there are animals showing (3) but not (1) or (2).

In order to make sure the absence of (1) I stipulate that the individual animal should be capable to live a completely solitary life, which excludes e. g. all mammals from the list of candidates.

Here, the criteria for "communication" are the following:

The message is created by a defined action of the animal.
The message is an object, separate from the animal's body.
The animal is able to interpret the message at a later time, i. e. removal or modification of the message artifact would result in a different behavior.

This question is motivated by the more general question whether the ability to communicate necessitates a social context.

EDIT: In order to make it clearer what communication could be, as suggested by the comments, here are a few examples:

territory marking: matches the categories (1), as a signal to rivals and probably (3), as a reminder for the territory owner.
alarm call: matches (1) and/or (2)
behaviour of the Honeyguides: a typical example of (2)
creation of trails: may have a communicative function (e. g. for ants), and is also seen with solitary animals. Is there a case, where the communicative function is predominant and all other criteria are met?

Here is why I think that some classes of species can be excluded:

mammals, birds: every individual enjoys parental care, which has a communicative aspect of type (1)
plants: may be able to communicate with other plants or animals, but self-communication seems hard to imagine.


texts: why hiv genome not attacked by lysosome in macrophage

texts:
HIV cells lifecycle in macrophages suggests the early phase with naked genome entering the macrophage along with reverse trancriptase enzyme. i am thinking that macrophages are abundant with lysosomes and so called defense sodiers of the body who engulf all pathogens and kill them with lysosome action.

My questions

my question is that why this soldier is not able to distinguish a foreign and rather weird kind of genome of a retrovirus and not sending lysosome to act upon it at the very moment of entry of genome.

My second question is that why do T LYMPHOCYTES undergo lysis but macrophages are not affected?


texts: How many proteins could participate in a complex

texts:
Disclaimer: I’m a computer science student with minimum knowledge of biology.

I’m working on an algorithm to cluster proteins in Protein-Protein-Interaction Networks to find protein-complexes. While working on that I stumbled upon the question how many different proteins can be part of a protein complex. (I'll call this the size of the complex from this point.)

I started by counting the the participants from all Corum complexes.
I got sizes ranging from 1 to 143:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33, 36, 37, 38, 40, 44, 45, 47, 48, 62, 68, 78, 80, 104, 143]

The distribution is skewed to smaller sizes with 3 participants counted 1465 times and most of the bigger sizes from around 30 counted 1 or 2 times.

{44: 1, 36: 1, 32: 1, 47: 1, 78: 1, 48: 1, 31: 1, 143: 1, 40: 1, 26: 1, 38: 1, 62: 1, 104: 1, 23: 1, 20: 2, 22: 2, 33: 2, 80: 2, 37: 2, 45: 2, 28: 2, 68: 2, 27: 2, 30: 3, 19: 3, 24: 4, 25: 4, 18: 6, 17: 11, 15: 19, 1 6: 21, 14: 23, 11: 25, 12: 28, 13: 30, 10: 55, 9: 57, 8: 72, 7: 83, 6: 100, 1: 127, 5: 237, 4: 499, 2: 1370, 3: 1465}[Sorry for not sorting...]

My main question from this first dip into data is, are there any assumptions to make about the size of complexes? Are these big complexes for example special cases and normally complexes are limited to a size of around n?
Is there maybe even an upper limit of participants in a complex?

Anything would be helpful for me to minimize runtime.


texts:
According to CDC, non-bite exposure includes scratches, abrasion, and contamination of the mucous membrane from a rabid animal's saliva.

So, is it possible to catch rabies if a rapid animal barks near you? I mean, it can have some tiny droplets of saliva on it, right? Or the contamination of the mucous membrane should come from licks as stated by WHO?


texts: How to restrict a BLAST search to include only a few protein sequences?

texts:
I am performing a BLAST search and I need to filter the output to a certain family of proteins.

Specifically, I need to get matches within the CYP152 family of the Cytochrome P450 proteins. I can parse the results to just P450 proteins fairly easily as the "hit def" field in the output will contain "Cytochrome P450" somewhere in there if it is in fact a P450 protein sequence, but the same is not true for CYP152.

Is there some way to do this? I am using ExPASy BLAST:

http://web.expasy.org/blast/

Thanks in advance


texts:
Why does being taller provide advantages for Bryophyta but being
  shorter is better for Marchantiophyta? What disadvantages could being
  taller have?

I think that by being taller, you have better spore dispersal. However, the problem with being tall is that the temperature flucuates more. Am I correct? Is this the right answer? Am I on the right track?


texts:
This post is regarding a follow up on my initial post on "Properties and life cycle of chondrocytes and tenocytes".

I am elaborating on my question on the lifespan of tenocytes and chondrocytes.

From what I have read, tenocytes and chondrocytes form from mature stem cells, more specifically Mesenchymal stem cells. These cells can replicate through mitosis, and are present in the body in different tissues like bone marrow. These cells are the key in the regeneration of diverse tissues.

When the cells that inhabit tendons or cartilage die, do new MS cells travel to the tendon or cartilage area and diffentiate into a new tenocyte or chondrocyte? Are tenocytes and chondrocytes continuously replaced?


texts: Why can't our eyes smoothly transition from side to side without focusing on a moving object?

texts: Why are we not able to slowly and smoothly look from side to side, or up and down in a single and smooth transition, given that we are able to do this if our eyes are focused on a moving object?


texts: Why doesn't the herbicide 2,4-D damage lawn grass?

texts:
I sometimes use 2,4-Dichlorophenoxyacetic acid to control broadleaved weeds in lawns. It is selective, and quickly kills the dicot weeds, while other plants are unharmed.

2,4-D is a synthetic auxin, a class of plant hormones. It is gets taken in through the stomata on the leaves, and is transported to the meristems of the plant. This causes uncontrolled, unsustainable growth, and the plant wilts, and dies.

Why doesn't this affect most monocotyledons?


texts: Resources for finding all drugs of a certain class

texts: I may be embarking on a project involving a fairly extensive healthcare records data set, looking for the use of a particular type of drug (for example, "Proton Pump Inhibitors"). But these drugs are usually listed by their trade or generic names - is there a well maintained resource for looking up what drugs are members of a certain class (if class is indeed the right word)?


texts:
In A level Bio today we talked about abcesic acid as a stress hormone, and its ability to reduce osmotic potential around guard cells to close stomata.

My question is, is abscesic acid in sorghum bicolor leaves responsible for its ability to roll up in lack of water?


texts: Etymology of eccentric/concentric contractions

texts:
I was wondering if anyone knew why the terms eccentric and concentric were chosen to refer to lengthening and shortening muscle contractions?

The basic etymology of the words are to do with alignment with the centre of something. Eccentric is derived from the Greek for "off centre" and is also commonly used in bio-mechanics, another branch of sports science, to refer to a force applied out of alignment with an object's centre of gravity. I couldn't see how this definition applied to a lengthening muscle contraction, and haven't been able to find any information on why the terms were chosen.

I'd appreciate any help.


texts: Are multi-chain proteins synthesized as one biological unit?

texts: Are multi-chain proteins (especially homo/hetero-dimers) synthesized together as one overall unit or are they separate monomers which bind together at some point after synthesis, and are there any relevant factors to know about this process?


texts: What is this agglomeration of pink cells I found attached to a stone?

texts:
Photo taken in a garden in Singapore. The organism is attached to a stone, close to water. Many of these were there.

Size approx 3cm.

The shell of this eggs is very soft. When touched, a pink colored liquid drops out.


texts: Reproductive isolation causing evolution

texts:
My course book says about reproductive isolation that it does not allow the interbreeding among the individuals of different species. It also says that it is a cause of evolution.

How is this cause of evolution?


texts: Is it possible to feel pain in some part of a body, but the pain "feeling" is introduced somewhere else?

texts: Is it possible to feel pain in some part of a body, but that the cause of the pain is situated elsewhere in the body? For example, somebody feels pain in his toe, but it turns out that this pain is not signaled by nerves in his toe, but caused by a damaged nerve in the spinal cord, or somewhere in the brain.


texts: Why is prothrombin time used to monitor warfarin and not activated partial thromboplastin time?

texts:
Warfarin is said to change prothrombin time (PT) but not activated partial thromboplastin time (aPTT) (for practical purposes at least anyways, not really sure). But looking at the mechanism of action of warfarin, I dont see why that is.
Warfarin works by inhibiting vitamin K, or more specifically, vitamin K-mediated post-transnational modifications of certain clotting factors (X, IX, VII and II) which are important for the activity of said clotting factors. Warfarin affects factors in both the extrinsic and intrinsic pathway (and maybe a bit silly and irrelevant, but the same number of factors in each too; 3 by 3!). So, why is it that PT is affected by warfarin but aPPT isnt? I looked alot and couldnt really find any satisfactory answer (there werent many answers to begin with either). What I've found and have gotten from my professor are the following points:

Warfarin's effect is more pronounced on PT because factor VII (the first factor in the extrinsic pathway) has the shortest half-life and is therefore the quickest to get depleted. But in that case, warfarin usually takes a few days to be considered effective enough to stop administering patients heparin with it; wouldnt all the affected factors be depleted enough by that time to also affect aPTT?
Warfarin affects factor VII, which is the initiating factor (tissue factor aside) for the extrinsic pathway, which is why it affects PT more? Honestly I don't know how these tests work exactly so I'm not sure if this would matter. This was what my professor answered with when a student asked (or at least it's what I recall).


texts: how many copies of tp53 (p53) gene do we have?

texts:
I just started studying biology so I almost have no knowledge.

I learned about the tp53 gene and I just wanted to know how many copies of tp53 gene we have?


texts: If you injected a tumor with epithelial cells infected with the Rhinovirus, would this still evoke an immune response as it would with the respiratory system? Secondly, what is the specific reason the Rhinovirus is only attracted to the epithelial cells in the respiratory system.  Do these cells give off a specific chemical signature in which the virus is attracted to?


texts: Why was not RNA completely replaced by DNA when the RNA world evolved into a DNA and protein world?

texts: If DNA just has a slightly different chemical composition from RNA, why can't DNA act as a catalyst and why hasn't it replaced RNA? Here, I am talking in terms of evolution, shouldn't evolution just replace all the RNA with DNA?


texts: Which plants are healthy to keep in the bedroom at night?

texts:
I know that there are no plants which release oxygen in the dark (Can plants produce oxygen at night (without light)?).

I also know that some plants can clean toxic agents from the air (Nasa Clean Air Study).

Are there any plants which have health-beneficial properties specifically at night, i.e. in the dark?

Assume, if you'd like, that 12 leprechauns bring the plants to your bedroom the moment you turn off the lights and place them outside your house when you turn on the lights in the morning. Can bedroom plants still be beneficial to your health in this case? If so, which ones and why?


texts: What is the most durable electronic pipette?

texts:
We have a routine task of pipetting substance concentration series in triplicate on cell cultures under a laminar hood. To speed up the process, we use an electronic pipette in the repetitive pipetting mode and an electronic dispenser. The pipettes are several times a day wiped with 70% ethanol for decontamination, as they are moved to and from the hood. Up to date, we used the Eppendorf ones, but they fail after roughly a year of use. The failing parts are usually piston position sensor and pipette tip sensor on electronis dispenser.

Does anybody have an experience with the durability of different brands of electronic pipettes (Socorex Acura electro, Gilson Pipetman M, MT E4, maybe, others), especially under a laminar hood in repetitive pipetting mode?

Thank you in advance!


texts: I recently found out that alder trees have root nodules which contain nitrogen-fixing bacteria and that alders are primary colonizers in primary succession. That leads me to this question: since there are really no fungi in the soil and since the alder is a colonizing species, where does the fungi come from? Or is my assumption that there are no fungi in the soil incorrect?


texts: What are some examples of coupled reactions in the cell?

texts: Except DNA Synthesis that requires ATP hydrolysis, which other reactions require activated carriers?


texts:
I've been reading paper on ancient horse genome (Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse) and in abstract authors mention term continuous selection:

  We also find evidence for continuous selection on the immune system and olfaction throughout horse evolution

Can someone please explain what it means? What is continuous selection? Is it selection without interruptions, but what are those interruptions?


texts: Size of classical liver lobule across species

texts: A classical liver lobule is made up of a central vein and the portal triads.  A typical human liver weighs around 3 lbs. , while a typical bovine liver weighs around 12 lbs.  I was wondering if anyone had a reference that might discuss the size of a bovine liver lobule vs. the size of a human liver lobule.  Specifically, is the bovine liver lobule also larger than a human liver lobule?


texts: Why is the blood pressure in the superior vena cava during inhalation less than during the exhalation?

texts:
For further investigation into the progress of the blood pressure, we will measure a patient's blood pressure in the superior vena cava measured during inhalation and during an exhalation. His heart function remains the same during the measurements

Why is this subject's blood pressure in the superior vena cava during inhalation less than during the exhalation?


texts: What's the difference between stabilizing selection and balancing selection?

texts: I came across these terms in Darwin's "Origin of Species" and I wasn't sure what the difference is.


texts:
I am new in Bioinformatics and recently studying UCLUST algorithm by Robert Edgar(2010). It is a fast sequence searching and clustering algorithm. The algorithm is heuristic based. I studied that first, this algorithm finds unique common words(k-mers) between a query sequence and a target sequence.(one of the sequences from sequence database). If there are enough common k-mers between a target sequence and a database sequence then it is selected for the alignment in the next step, otherwise skipped. All such sequences having enough common k-mers are selected. Target sequences are compared in order of decreasing common k-mers.

In next step, HSPs (High Scoring Segment Pairs) are identified. For this purpose, exact matching words between a query sequence and a target sequence (one of the sequences selected in the previous step) are found. I AM CONFUSED AT THIS POINT. Is it necessary that these matching words(between the query sequence and the target sequence) be at same positions ?

Kindly if some one explains with an example, will be very help full.

Any guidance will highly be appreciated.


texts: Distribution of dendritic spike generating ion channels on the dendritic tree

texts:
Is there evidence that dendritic spike generating ion channels are distributed unevenly on the dendritic tree, with higher density near the branching points of the tree than along the unbranched segments? Or the other way around? Or is there no observed correlation between density and local geometry of the tree?

If there is, i.e. if those channels tend to condense near branching points: which mechanism drives them to do so?

[I believe it could make sense to have the spike generating channels condensed at branching points: there they could act as local logical gates, summing up the inputs of the afferent branches (see Poirazi et al, Pyramidal Neuron as Two-Layer Neural Network).]

[There is also a figure in Larkums article on A cellular mechanism for cortical
associations in which at least one electrode is placed close to a branching point. Maybe because there are extraordinarily many spike generating channels?]


texts:
A recent1 AncestryDNA commercial highlights a customer who discovered that she was 26% Native American.

Credit: ancestry.com/dna

You can see the full commercial here.

My question is, how can this be?

What combination of parents' race lineage would dictate that a person is 26% Native American (or any other race for that matter), and how many generations back would one have to go to achieve these numbers?

1. Recent to me, I don't watch much television.


texts:
I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit.
Why can hair grow without limit while eyebrow cannot?


texts: Do apes and humans share 99% of DNA or 99% of genes? What is the difference?

texts:
I made an answer on the Scifi.SE that can be read here. It is about how the characters in the story Jurassic Park might have gotten DNA for all the species shown.

In my answer, I said this:

  Apes and Humans, for example, share over 99% of their genes. That means the difference between our species is less than 1% of our genes. In fact, all life on Earth shares about 50% of it's genes.

but in the original posting (before someone edited it) I chose to use the word DNA instead of genes.

He left this comment in the section to explain the edit:

  Sorry, I'm a biologist, I can't help it. Humans and apes share 99% similarity in the coding sequences of their DNA, the ~5% that codes for genes, not on all the DNA. I simplified this to genes for the answer.

I have a basic high school understanding of DNA and genes, so I'm afraid I fail to see the difference between using "DNA" or using "genes" in my statement. I understand that genes are specific sequences of DNA that are used by the cell in some way. I understand that DNA is more generic, including all of the strands, whether they are used or not, whether they seem to code for something or not.

So is it wrong then to say that apes and humans share 99% of their DNA or is it equally correct to say "genes"?


texts: Perplexing by the way of estimating the shared or different genes between humans and chimps

texts:
We share 98.5% genes with chimps (it means we have 98.5% same DNA sequeces ),so there is about one percent difference .It means we can approximately differ from them by one base pair every hundred base pairs on average.

The following is my question.

A human receive 3 billion base pairs from each of parents ,and has six billions in total .Do the math by using one hundred to divide six billions and then it equals sixty millions.

Due to that, The person have ,on average ,sixty-million-nucleotide differences with a chimp.

However,the professor of the online courses I attended said it's thirty-million-letter differences.

Dose that mean it's counted on haploid?Why?

Also ,I'm not sure that about one percent difference is calculated on one base pair or one nucleotide every thousand base pairs or nucleotides .Because he mentioned the both.

This is the course ,my questions occur at 1:58

In another course , similar questions occur at 3:11


texts: Do different species of bacteria have distinct absorption bands?

texts:
Do bacteria of different species absorb different wavelengths of light? How different?

Most of my searching has lead to topics about Optical Dispertion which seems to be species independent as opposed to single species.


texts: Is presence of air necessary for silica gel to absorb moisture?

texts:
I am a biologist currently doing field work where I need to quickly dry leaf samples using silica gel crystals.  I use the orange indicating kind that are 2-4mm in size.  The setup is like this.  I stuff 1-2 leaves in a manila paper envelop which I drop in a ziplock bag containing ~1/8th cup of silica gel.  Then I squeeze out most of the air before sealing the ziplock.  The end goal here is to extract DNA from dried leaves when I am back in the lab.

I have had varied results in terms of drying and looking to achieve the maximum efficiency.  Recently it occurred to me whether squeezing air out is actually counterproductive to fast drying.

So my question is, whether presence of sufficient air necessary for silica gel to absorb moisture from leaves?  Essentially I am creating partial vacuum inside the ziplock.  Is that keeping silica from doing its job?


texts:
I have done IFA (immunofluorescence assay) previously but i targeted only one protein or i tagged my endogenous protein with GFP/RFP then i performed IFA. I want to do the IFA in parental cell line (HEK cells). My aim is to show the two proteins are co-localized or not?

Protein-1 (secondary antibody Mouse)
Protein-2 (secondary antibody Rabbit)

How can i co-localize two different proteins in the same sample? Which primary antibody do i have to add first?  can any one please suggest me something?


texts: Which sex has higher variance of reproductive rate in modern societies - male or females?

texts: Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that reproduction is more concentrated in some subgroup of given sex so this subgroup transfer their genes at higher rates then average rate in whole population. The next question would be 'is that subgroup somehow homogeneous' ?


texts: Which database has the ready made 16S rRNA Multiple Sequence Alignment File that I can download directly from?

texts:
In my case, I need the ready made 16S rRNA Multiple Sequence Alignment File for E.coli and use it to generate the phylogenetic tree file in Newick format. I've tried using the one from utexas website, but I get too many errors when using the alignment file for tree generation, either the file size is too big or the input file is not a fasta file, so I tried to read the alignment file in R using read.alignment() function and it reads fine. Still I get this error when I used it to generate the tree.

So, can someone tell me where do I get a ready made Multiple Sequence Alignment File for 16S rRNA of E.coli being the reference sequence?

Thank you.


texts:
The DNA exists in linear and cirular forms. The latter form has interesting feature called Supercoiling. The more number of writhe makes it more supercoiled because of which it gets more compact. Hence the supercoiled DNA runs faster compared to other forms in a gel electrophoresis experiment.

But why does the circular DNA run slower than linear DNA? Isn't circularity supposed to make it compact?


texts: Anyone know what emerged from these cocoons?

texts: Found a little universe in the back of a ceramic decoration I put up outside in summer...the concave back was full of grainy soil and several exited cucoons...anyone know what critter this is/was?!


texts:
Not all men who take Viagra experience any sexual side effects about 40% have no change of sexual abilities on the pill. However like many women the drug in such cases cause a strong pain reduction without any considerable side effects. Also in some cases is able to eliminate persistent nausea and increase oxygen flow through the lungs.

Could Viagra be used for cancer patients or others who need to manage pain?

Update:

Roles for Sildenafil(or Viagra) in Enhancing Drug Sensitivity in Cancer


texts: If a person has a specific mutation in a gene, is it more likely he has other mutations in that gene?

texts: If a person has a specific mutation in a gene (2281 del/ins in a single copy of the Bloom BLM gene), is he more likely than the general population to have other types of mutations in the same gene?


texts: Which DNA would sperms contain from a transplanted scrotum?

texts:
We had a discussion at the coffee break today about transplanting a scrotum.

Let's assume that it's possible.

Would the produced sperms contain the DNA of the donor or the one that got the scrotum transplanted? Can you explain why?


texts: Can butterflies still fly after their wings are touched?

texts:
When I was a kid, I was told not to ever touch a butterflies wing, as it would lose its ability to fly. This was because of some dust which was supposed to be in place on the wings and when disturbed it had the described consequences. I doubt at least the story about the dust, which sounds a bit too much like "fairy dust", but am I right?

What damage will be done by touching a butterfly?


texts: The "truce of the watering hole" -- is it completely discredited?

texts:
In short, the idea comes from Kipling that animals observe a sort of truce around watering holes and prey animals do not have to be on guard (as much?) from predators in the vicinity.

I have read that this is false, that predators might even wait around watering holes for prey. However: Cleaning stations in the ocean seem to have rules and a truce (and a fish violating these rules, primarily not to attack other fish waiting to be cleaned is attacked by other fish of various species). So the idea of a truce at waterholes, perhaps only partially observed, is not that far fetched.

I wonder too if lions, for example, at some level understand that in order to survive they need prey to be able to eat/drink and breed. While this also sounds too sophisticated, is it any more sophisticated than the behavior of killing cubs so that females come into heat?


texts: Folded stem on apples - does it have a name?

texts:
I have some Newton Wonder apple trees. One feature of the apples it bears is that the flesh around the stalk is occasionally elongated out of the calyx. Below is a picture that shows this on the near side.

Is there a specific name for this feature in apples?


texts: Are there animal models for Clostridium difficile that better replicate human infection than hamsters?

texts:
So I'm looking for some information on the infectious dose necessary to colonize a human with Clostridium difficile. There's no human challenge studies, and since it's not a foodborne pathogen, little we can get from outbreak data.

Which leaves me looking at animal models, to at least get the shape of the probability of infection based on a given dose. But the papers on hamsters makes it appear that they're infected rather easily, and that this infection is particularly severe.

Is there another animal model that more closely mimics the infection dynamics of C. difficile in humans?


texts:
How does glutaraldehyde kill bacteria?

After disinfecting, does it leave the corpses of the bacteria to count?

Does it leave bio-film in tact?


texts: Humans have three cones of color light, red, green and blue. If the region of the green cone is hit by his photons we will see green light. Now we don't really receive green light but our eyes and brains are 'making' it to look green. But if all the different cones are hit by their photons we will see white. Now the question is why is that white? Why isn't our brain just keeping these different colors, is this a kind of black out of our brain or an overwhelming of input making us blind etc?


texts: allogeneic organ transplant and the immune response

texts: What happens when an allogeneic organ transplant is performed on an immunocompetent recipient vs. when it is performed on an immunosuppresed recipient using a donated organ with immunocompetent cells?


texts:
As far as I know, the oesophagus in vertebrates has no digestive or absorptive function. It is simply a conduit from the mouth to more distal parts of the gastrointestinal tract. Why have it at all, then? What evolutionary advantage does it give? Why not have the stomach start right where the mouth/pharynx ends?

Could it be to make space for the heart?

A Google search did not yield any useful answers.


texts: Will a mosquito die due to blood clumping if it sucks blood from two people who have different blood groups? What will happen in its gut? Is there any mechanism to avoid clumping? Or do mosquitoes know what group it should suck?


texts: if an SNP were edited using CRISPR What are the chances that, absent artificial selection, wild type alleles would reemerge?

texts:
I am researching a fatty acid amide hydrolase (FAAH) SNP RS324420 and FAAH out microdeletion that together lead to reduced pain sensitivity and reduced anxiety (Moreira et al 2008).

The causative mutations for this new pain insensitivity disorder are: the
co-inheritance of (i) a microdeletion in dorsal root ganglia and
brain-expressed pseudogene, FAAH-OUT, which we cloned from the
fatty-acid amide hydrolase (FAAH) chromosomal region; and (ii) a
common functional single-nucleotide polymorphism in FAAH conferring
reduced expression and activity. Circulating concentrations of
anandamide and related fatty-acid amides (palmitoylethanolamide and
oleoylethanolamine) that are all normally degraded by FAAH were
significantly elevated in peripheral blood compared with normal
control carriers of the hypomorphic single-nucleotide polymorphism.
The genetic findings and elevated circulating fatty-acid amides are
consistent with a phenotype resulting from enhanced endocannabinoid
signalling and a loss of function of FAAH. Our results highlight
previously unknown complexity at the FAAH genomic locus involving the
expression of FAAH-OUT, a novel pseudogene and long non-coding RNA.

Br J Anaesth. 2019 Aug; 123(2): e249–e253.
Published online 2019 Mar 28. doi: 10.1016/j.bja.2019.02.019
I would like to know, theoretically if CRISPR was used to edit these genes in humans to allow  reduced anxiety and pain sensitivity,  'what is the probability that a recurrent mutation would cause the wild-type allele to reemerge in this gene',


texts: How do we call a region of low carrying capacity?

texts:
I am looking for a convenient word to define a region of the landscape where the  local carrying capacity (population size) for a given species is low but different from zero. The species is still present in this zone.

How would you call such area?


texts: Is the sex of siblings mutually independent?

texts:
I am studying probability, and one of the lectures I came across (Skip to 52:00) states that the sex of siblings is not mutually independent and that there is some correlation.

Can anyone tell me why? And if so, where is the evidence?


texts:
I am looking at identifying a tree for a friend who lives outside of Melbourne.  Being from Tennessee in the US, we don't have anything very similar to this at all and it doesn't look like any of the US tropical trees that I know of either.  Can anyone help?
This is the far away view of the tree
Specific location: It was taken in the laneway behind a property in Glen Iris, Victoria just outside of Melbourne (Australia).


texts: Are self pollinated plants genetically different?

texts: Gametes in pollen grain are formed during meiosis in the anther. And meiosis produces genetically different gametes. When the pollens grains are carried to the stigma to fertilise the egg cell of the different/same flower from the same plant, doesn't it produce genetically different flowers even though it is self pollinating because of the variation in gametes?


texts: This insect is in my house in North Carolina, USA. I think it shares similar body features of that of a wasp, but it is far too narrow and has what appears to be a long stinger. What is it?


texts: Cross section of actin network in neurites

texts:
for a simulation I am developing I would like to know how the actin network in neurites is distributed.

Is actin confined to the periphery or is the whole neurite shaft containing actin with a rather constant density?

If you have any papers backing up the one or the other view don't hesitate to pass the link.

Thanks for answering.


texts: Examples of plant families that contain species that are safe for human consumption and species that are poisonous to humans?

texts: I am trying to make a point to someone that just because two plants share a family and one plant is safe for human consumption, it does not follow that the other plant also is safe for human consumption. Can anyone provide an example I can use as proof?


texts: As a child I watched tiny fiddler crabs living in conical shells, and many years later I find that people study fossil turritellids. So now I wonder: how old are shells, typically, that you see on beaches? Do they wear out after a year of sand abrasion? 100 years, a million? Is it known?


texts: How can I determine where meiosis occurs in the life cycle of a plant?

texts:
To fill out this diagram with the mitosis, meiosis, and ploidy , we start with the definition that spores are haploid (N).

Based on knowing that as the sperm and eggs are N, the gametophyte is also N (as only fusion can make something go from N to 2N).

Then I know that the link between spores and gametophytes is mitosis, as we go from N to N.

Similiarly, as zygotes are 2N, and spores are N, either the link between zygote to sporophytes OR the link between sporophytes to spores must be meiosis.

Can I figure out at which stage meiosis occurs with this information, or do I need to know more about the definitions of the different parts of the life cycle? How do I know that sporophyte to spores, and not zygote to sporophyte, is Meiosis?

 (Source)


texts: Is this plant lantana camara? If not what is it?

texts:
I was in a botanical garden recently and wasn't able to find the tag on this plant. The diameter of the entire flower tended to be around 5cm.

Google seems to suggest its lantana camara but I'm not 100% convinced yet.

When rubbed, its leaves produced a minty aroma


texts: Want to know which insect it is? I often found it in washroom. Is it dangerous and how to control it

texts: This insect found in the wash room.  Its so fast and disappears once someone enters the washroom.  Is it dangerous?  Whats name of this insect.  How to control this insect


texts: Biological Neural Network Training for Babies

texts:
I am concerned by the fact that babies cant walk because the muscles in their limbs arent developed and tuned to give directional control, it takes years before babies gain mobility and dexterity. So technically the neural nets in the motor cortex requires years of training before that capability is achieved.
However, when the babies are born they dont need training for ocular muscles for directional control of their eyeballs (which is quite computationally challenging problem due to high degree of freedom compared to hinge movement) . Do biological neural network for occular muscles come pre-trained while the neural network for limb muscles come untrained by birth?


texts:
Last summer I was visited by this unusual golden fly, whose kind I have never seen before. It was impossible to scare away so I could take relatively good pictures.
The pictures on this hobbyist page suggest, it is a  "Golden blowfly". Those pictures were taken in Australia. The only paper I could find on golden blowflies locates the species in Australia as well. However, I took my pictures in southern Germany.
What is this fly? Is it an invasive species or native to Germany as well as Australia?


texts: What's the difference between the terms "gene map" and "genome"?

texts: It seems some sites arbitrarily restrict "gene map" to only a single chromosome, but others don't. Supposing we don't restrict it to just a single chromosome, is it different from "genome"? Are these two terms just synonyms?


texts:
I am reading the paper Cooperative Subnetworks of Molecularly Similar
Interneurons in Mouse Neocortex and a term "starter cell" apears there (page 6):

  This yielded tissue sections where SOM or
  VIP starter cells carry both nucleus-localized GFP and cytoplasmic mCherry

Does anyone know what a starter cell is?
(I couldn't find it on the web)


texts: This bird was found in my backyard in the north east of Italy. It's about 5cm long and can fly as high as 1.5m (so far).


texts: How to incorporate size data with shape in stereographic morphometrics?

texts: This may be an extremely simple point that I am missing, but how are you supposed to know the exact size of a structure being analyzed in three dimensions? When doing two dimensional morphometrics, you simply have a scale bar with your image. I know that microCT and some other methods may do this automatically, but some are now using free software like 123D Catch from Autodesk to create mesh models. In this case, are you strictly restricted to shape independent of size? If not, how do you add in a 3D scale bar, so to speak?


texts:
My attempt:  I looked for the TACs because I thought this would be AUG in mRNA and ultimately Methionine (the start codon). But apparently, that's not how you do this problem.  Im confused because the answer (shown in red) doesn't have any TACs and the boxes seem to start at random places.  I am also confused as to why my professor drew a box around both strands.  I thought only one strand at a time was turned into mRNA?

UPDATE:  It has occured to me that the entire strand is transcribed and then the introns are removed.  So I know why not to look for the TACs.  But now, how can I identify the exons?


texts: How does a gene "know" what to change to?

texts:
Excuse my ignorance but I've always been curious about this...

For example, a frog is red, but it starts living in a green forest. Over time the frog becomes green to camouflage. But a gene can't see and I'm sure there's no mechanism for color info to be transmitted to individual genes from the brain. So how does a gene know to pick green over, say, blue?


texts: Phototropism or Hydrotropism is a more important factor for trees beside the lakes growing bending to the water?

texts:
I see a lot trees beside the lakes are growing bending to the water and I wonder why. After reading this I think it might be a combined effects by:

Phototropism: the lake works as a mirror and sunlight are reflected
Hydrotropism: of course, Hydrotropism...

But which one is a more important factor? Phototropism or Hydrotropism?


texts: From my understanding melanocyte stem cells (McSCs) stop being produced and we have a finite reserve that gets depleted with time. They're at the origin of melanocytes that create hair and skin pigments. Our hair turns white when we don't have any more McSCs. So why does our skin stay the same color with aging?


texts: Do nematodes have organ-level organisation?

texts: Some introductory biology books state that nematodes have a pseudocoelom. So, they have a false body cavity. So, does it also mean that they have organ level body organisation?


texts:
If I am blood type B, what are all the possible genotypes that could be expressed by my parents?

I think it might be 16 but I was reading online and saw this:

  Similarly, someone who is blood type B could have a genotype of either
  BB or BO.

So if someone can help me answer this, that would be great.


texts: Does recombination increase the additive genetic variance for fitness?

texts:
On this article, first column, eighth line of the introduction:

  By bringing together favourable alleles from different chromosomes, sex and recombination increase the additive genetic variance for fitness [..]

Can you please help me understanding why does recombination increase the additive genetic variance for fitness?

Note: In reaction @mgkrebbs comment, I think that given the subject of this article, when talking about different chromosomes, the authors actually referred exclusively to homologues chromosomes. My question concerns the second part of this sentence anyway: "Why does sex and recombination increase the additive genetic variance for fitness"?

Here is another question on the same article


texts: What happens if a speciation event causes the new species to evolve out its clade's defining trait?

texts: If a speciation event occurs to a member of the strepsirrhine clade in such a way that its rhinarium is selected out, would it stay a strepsirrhine?


texts: I have read somewhere that viruses and other microbes can not penetrate skin but what about sweat pores? Can viruses pass through these pores?


texts: If you suspended your DNA like a rope in its 6ft full length, could you feel it if you waved your hand through it?

texts:
Maybe a silly question but I was wondering about this.  Trying to understand how small things are.

I have read that the DNA in a single cell if stretched out, would be about 6 feet long.

If you actually stretched it out and had something hold it - so that it was n a vertical line from about 6 ft to the floor, and then

would it cast a visible shadow?
if you waved your hand through it, would you be able to feel it?


texts:
This bird is a frequent "visitor" at a lake south west of Berlin, GERMANY.

For more pictures here's a link:
https://goo.gl/photos/ADVSZwbDQUpbomCBA


texts: Do we actually know the molecular dynamics of any enzyme?

texts:
That is right, is there a limitation, say Heisenberg's uncertainty principle or something that limits our understanding of machinery of enzymes at atomic level? Can we know how do they actually work?

As far as I can tell, there is no explanation of actual design and working principles of any enzyme at atomic scale. Even the nobel prizes are given to discoveries not related to molecular details but rather pathways in which enzymes are not the primary concern, they are just represented as simple geometric shapes.

PS: I know that we have the exact molecular structures of some enzymes discovered using crystallography techniques, but even then, do we know which parts execute which function and how?


texts: What constitutes FDA's First in Class designation for New Molecular Entities?

texts:
What constitutes a First in Class designation for new molecular entities? I've seen this term on FDA documents, as well as in databases (Chembl for example), but I was curious if there are any set criteria for First in Class drugs? The easy definition, in my mind, would be a drug that hits a novel target given its indication. However, if you look at antifungal drugs, you see that drugs with the same target for the same general indication (anti-fungal) treat completely different fungal infections because of their pharmacokinetics.

Are there discrete criteria for the FDA's first-in-class designation for New Molecular Entities?


texts:
I have a city garden (see picture below) and yesterday I was nurturing it and I pulled up a small plant. I saw its root system and laid it in the sun to dry a bit and then scraped of the rest of the earth from it. That gave me a better look at the roots.

Then the question appeared to me. How do roots obtain water and nutrition from their environment. I mean what structures are we dealing with and how does the uptake take place?


texts: AIDS can easily pass from mother to the newborn, then why do we not consider it to be a congenital disease (or syndrome)


texts:
Having a look at the corpus callosum one sees that the axons passing the corpus callosum (the  commissural fibers) connect mirror-symmetric counter regions of the cortex (roughly).

Is there a model that explains how the growing axons find their way to their far-away targets in this highly structured way?

(One possibility would be that the counter regions originally were close to each other but separated during brain development.)


texts: Atelectasis due to decreased surfactant in lungs

texts:
Surfactant is a protein lipid mixture produced by alveolar pneumocytes composed of Dipalmitoyl Phosphatidyl Choline lipid, apoproteins and calcium ions.
This surface lines the alveolar epithelium thereby reducing surface tension preventing lungs from collapse.
Atelectasis is collapse of lung mainly due to lack of surfactant.
Moreover it may also be due to obstruction of the airway tract.

My question is why is this surfactant found to be lowered in patients who have undergone cardiac surgery under pump oxygentor? Why does long term exposure to 100% Oxygen affect the surfactant.
Is it due to its chemical composition or is it something to do with pulmonary circulation?

This Wikipedia article states alveolar collapse due to Oxygen Toxicity
http://en.m.wikipedia.org/wiki/Oxygen_toxicity


texts: Glucose Carrier Proteins in Cell Membranes

texts:
I'm using Campbell's Biology textbook, and it states that certain carrier proteins transport glucose across the cell membrane much faster than would occur normally. It states that the "glucose transporter" is an extremely selective protein, which doesn't accept even fructose, which is an isomer of glucose. However, another hexose, galactose, appears to me to be even more similar to glucose- it's just that one of the H-OH pairs is flipped. In comparison, though fructose is indeed an isomer, it's a ketose, but glucose and galactose are both aldoses. Given this, I'm pretty sure galactose is more similar to fructose.

My question is: is the carrier protein specific enough to carry only glucose and not even galactose? If it isn't and it's able to carry galactose, what would happen if galactose was transported into the cell in greater quantities?

Note: I'm a bio beginner, so please have some patience if my questions are nonsensical or my facts are incorrect, any corrections would be welcome.


texts: Are amantadine and rimantadine MOAs unknown to evolution?

texts:
Are any natural (human or otherwise) antiviral mechanisms similar to the antiviral mechanisms of amantadine and rimantadine, or are these mechanisms undiscovered by evolution? Are drug researchers discovering completely new mechanisms to attack viruses?

http://www.rapidreferenceinfluenza.com/chapter/B978-0-7234-3433-7.50014-1/aim/mechanisms-of-action-of-antivirals

The mechanism by which antiviral drugs (amantadine and rimantadine) interrupt the replicative cycle of influenza is illustrated. M2 inhibitors prevent the M2-mediated acidification of the interior of the virus while it resides in endosomes and the subsequent uncoating of the viral genome, thus inhibiting viral replication. Neuraminidase inhibitors (NAIs) prevent cleavage of sialic acid residues and thus newly formed virus cannot be released from the cell surface to infect adjacent cells; also, virus particles remain associated to one another.


texts: How to reduce the number of sequences in a Multiple Sequence Alignment?

texts:
I have a Multiple Sequence Alignment, where there are around 5000 sequences. There also exists many sequences where, there are so much of non-sequenced regions (for instance, AU----CGGGCA--NNNNNNNNNN).

So, by trial and error, I found a threshold value of 25%, so I removed the sequences which contained more than 25% of non-sequenced region (N's here), retaining around 400 sequences in the alignment, by writing a simple R script.

But, I would like to know, if there is any other standard method to do this, because I do not think, removing sequences based on finding a threshold for the percentage of non-sequenced regions, by trial and error is more efficient.If there is, can you please tell me, how to do?

Thanks in advance.


texts: Do humans have skin cells that trigger oxytocin release in the brain?

texts:
I was reading an article by Montgomery on the therapeutic effect of pets (Boston Globe, January 12, 2015), and I found this quote:

  All animals appear to have cells directly under the skin that activate oxytocin in the brain. So gentle touch — from grooming your
  horse’s coat to making love with your spouse — is a powerful trigger.
  But so is simply thinking about someone you love, whether it’s a
  person or a pet. And in fact, a small study published this fall at
  Massachusetts General Hospital found that MRI scans of women’s brains
  lit up in the same areas when shown pictures of their pets as when
  shown pictures of their children.

Do humans have oxytocin triggering skin cells or formations under the skin? If so, are there higher concentrations of these cells in certain areas of the body? In the human erogenous zones, like neck, lips, etc?


texts: Alcohol effect on heart and vascular system

texts: How does alcohol weaken heart muscles and why does it increase blood pressure both temporarily and long term? Is the long term effect due to increase of plaque or is it due to other effects?


texts:
(Apologies if this is a too weird/inappropriate question in this forum. I only thought that I ask it since it happens to be part of human life.)

The skin on a human typically blocks many substances that could be harmful for the organism. One area that is not covered by skin, however, is the "glans penis" (the tip of the penis).

Considering that the surface on this area seems to become more stretched during erection, it would look like erection causes the tip to allow more substances to pass through than otherwise.

Are there any studies about how erection affects the porosity in this area of the body?


texts:
My textbook "CGP AS-Level Biology Exam Board: Edexcel Complete Revision & Practice" says xylem is a tissue.

Then I read from this website that "[Xylem's] major components include xylem parenchyma, xylem fibers, tracheids, and xylem vessels." Therefore, from my understanding, xylem is made up of multiple tissues including xylem parenchyma tissues, xylem vessel tissues and etc to carry out the functions of transporting water and nutrients in plants? Therefore that would make xylem an organ instead of a tissue?


texts: Development threshold of a blowfly species differ depending on situation?

texts: Within a species, does the lower development temperature threshold remain the same in all situations (also known as the development zero temperature)? For example, would the temperature threshold be the same for larvae grown on small carcasses compared to large carcasses? e.g. mouse carcass compared to human/pig carcass.


texts: (secondary) human/primate advantages over other animals?

texts:
I am trying to understand the advantages that humans have over other species, besides what you could call 'sentience-critical'.

What I mean by this is, the first set of answers you'll get is "more capable brains (in general), opposable thumbs, tools, comunication". But all that is core to sentience and civilization, not primates. I am more interested in the second set of answers, such as 'better temperature management'.

I suppose the question is, what advantages do primates have over other animals? Or, what traits are likely to be missing, compared to humans, from a hypothetical non-primate sentient creature?


texts: Why does Citric Acid occur in Citrus fruits?

texts:
Why is there so much citric acid in citrus fruits? And how did it evolve i.e. what did it come from? Is it a by-product of the ripening process?  Why have citrus fruit evolved a particularly high amount of citric acid compared to other fruits? Was it due to particular selection pressure for acidic fruits or was there a genetic bottle neck that caused this such as human cultivation?

I've been trying to search for this but google scholar isn't throwing up anything so I'd really appreciate some help.


texts: Does every wave length of UV kill bacteria?

texts: Will every wave length of UV work for killing bacteria? So will UV A, UV B and UV C all work? Or will only the shortest of the three, UV C, work? Also, will the average UV lamp help against bacterial growth (if it is shone on an object for 3-5 minutes for example)? What about a longer period: a bacterial colony in a petri dish under an average household UV lamp for a day? Would the growth be reduced noticeably? Or would the change be too small to notice when using the average UV lamp? Does the type of UV also matter for this (A/B/C)?


texts: Why is there no way to remove an immune response?

texts:
We've known for a long time now how to "add a new entry to the database," as it were, of immune responses.  It's called vaccination, and it's been one of the greatest success stories in the history of medicine.

And yet, allergies and autoimmune disorders, both caused by an immune system gone rogue, are still serious problems today.  If it's so easy to add a new immune response, why don't we have any way of deleting one?


texts:
In other words, what is the vertical distance between the deepest and highest point on Earth where life is found?

Life has been discovered at the bottom of the Mariana Trench, 13 km below sea level. It's hard to get deeper than this, but I'm not sure if this really represents the bottom of the biosphere. Elsewhere at sea, microbes can be found many kilometers below the sea floor -- would we expect to find life far below the Mariana Trench?

In the other direction, the biosphere arguably reaches as high as 435 km, the maximum altitude of the International Space Station. If the ISS is disqualified, then that number would be much lower, but again I'm not sure exactly what it would be. The highest recorded bird flight clocks in at 11 km, though it's possible that microbes regularly get dragged up higher than this by wind.


texts: Is it possible to become pregnant indirectly? For instance, if there is some wet semen left behind inside tight clothing, jeans for example, and a woman tries them on for a couple of minutes? What is sperm's motility after it's deposited on cloth in room temperature? Can sperm still swim inside from outside if it's near the vaginal opening in the cloth? What are the chances of pregnancy if the woman is/is not wearing any underwear?


texts:
Many psychopharmaceutical drugs change synapse chemistry or directly agonize neuroreceptors in the brain. For example, cabergoline is a D2 agonist.

How do these compounds enter the physical synapses? Are they simply lipid soluble and diffuse throughout all cells?


texts:
Have a modest background in molecular biology and presently considering a project that requires some knowledge of botany.  Specifically, I seek details on the epiphytic relation between the microbe pseudomonas fluorescens and flowering plants such as the orchid and rose.

    * What would be the relationship?  Commensalism or Mutualism?
    * What is the nutrient source for Pseudomas? Life Span?
    * What becomes of the metabolic end products from Pseudomonas?
    * Does the plant alter its surface properties to accommodate Pseudomonas?


texts: I saw a nearly jet black squirrel in ardeche today,  carolinensis have invaded the UK and Italy, however I didn't find news about their arrival in France. Was that black squirrel really a Canadian species?


texts:
After rain, we often find shrimp-like creatures in the puddles left on our concrete patio. We have also found them in the cat's water bowl (on the same patio). They are pink in color, and around 3mm long.

The idea of shrimp on land seems absurd, but that's certainly what they look like.

We live in Okinawa, and even long-time local residents don't seem to know what they are. We're on a cliff 10 meters tall, right next to the beach.

My questions: what are they, and how do they magically appear after rain? From eggs that are lying dormant on my patio, waiting for rain??

The alleged duplicate is quite helpful. My question is slightly different because I live beachside in Okinawa, not in central Florida, and my creatures are much smaller. Probably a related species, though one that doesn't seem to be familiar to the locals.


texts: I understand that the overall function is voluntary movement, but is it the same in the skin? Is the main function in the skin movement or is there a greater function? Could anyone could provide this information or at least recommend a site that could help me with this research, as I have been searching and I haven't been able to find the answer?


texts:
I have noticed that some older adults (40+ range) can have voices that sound much younger than their actual age (i.e. an adult sounds like an adolescent).

My question is: could any physical aspects play a part? For instance the size of the throat, the tongue or something else? I am assuming that there are no external factors that are influencing this (smoking, exposure to chemicals, physical trauma, etc).


texts:
This question tries to narrow down the scope of that question.

What is the statistical relationship between radioactivity and mutation rate? By how much would the mutation rate be lowered in a idealized world were radioactivity is absent?


texts:
Transferrin Saturation (TS) is a common laboratory test and its values can be used to diagnose a variety of medical conditions.
In healthy humans, and I assume it is the same for other species, TS is typically found to be around 30%. Values above 50% are considered very suspect of hemochromatosis. This means that in healthy humans, at least 50% of the transferrin found in plasma is useless, at least with regards to iron metabolism. In particular, the bioavailability of plasmatic iron does not seem to depend on TS.
My question is therefore: what is the reason for the low TS value typically found in humans? Has it any known evolutionary advantage? I have not been able to find answers in the literature. Thank you very much for your help.


texts: Why do stomata close in low intensity light?

texts: Stomata close during high intensity light to prevent excessive transpiration but why did they close during low intensity of light? Please explain in easy- understand language because i'm  in just 10th standard.


texts: Why do we fall asleep when our eyes are closed? When we lie down with our eyes closed, eventually we'll fall asleep. Why is that? Is our eyes closing some sort of trigger to our brain that says it's time to sleep?


texts: The skull is 4 to 6 inches long and still has tendons attached. I found this on a beach in central California, which leads me to think it's probably from a seabird. I believe this is from a smaller scavenger bird.


texts: Limited space for animals - how is that bad?

texts:
I am writing an English paper wherein I have to appeal for change in the way humans treat wildlife. I was initially given a situation wherein I took a ferry in a certain area and saw a dead baby dolphin.

Along the way, I (it is written in second person) apparently notice how little water is now available for the dolphins (due to some bridge being constructed).

What exactly is bad for dolphins (or animals in general) when they have limited space to roam around?

So far I thought of dolphins hitting boats due to the crowded state of the area in question.


texts: Horizontal gene transfer and Botulinum toxin

texts: Is it theoretically possible that any aerobic bacterium becomes able to produce Botulinum toxin as a result of horizontal gene transfer from Clostridium botulinum to that bacterium?


texts: Inbreeding Coefficient and Coefficient of Relationship

texts:
Wikipedia gives the following formula to calculate a "path of coefficient of relationship" between an ancestor $A$ and an offspring $O$:

$$\rho_{AO} = 2^{-n} \left( \frac{1+f_A}{1+f_O} \right)^{1/2} = \left( \frac{1}{2}\right)^n \sqrt { \frac{1+f_A}{1+f_O}}$$

, where $f_A$ and $f_O$ are the coefficient of inbreeding of the ancestor and the offspring respectively.

Question

Where does the term $\sqrt { \frac{1+f_A}{1+f_O}}$ comes from? Please explain why this multiplicative term is $\sqrt { \frac{1+f_A}{1+f_O}}$ and not something different such as $\frac{f_A f_O}{2}$ for example.


texts:
Reading [1] I found the sentence:

  Consistently, functional dissection of mouse and human wild-type and mutant RAS isogenic leukemia cells demonstrated induction of methotrexate resistance but also improved the response to vincristine in mutant RAS-expressing lymphoblasts.

I did not find a definition online yet. What is the meaning of functional dissection in this context?

[1]   K. Oshima et al., “Mutational landscape, clonal evolution patterns, and role of RAS mutations in relapsed acute lymphoblastic leukemia,” Proc Natl Acad Sci USA, vol. 113, no. 40, pp. 11306–11311, Oct. 2016.


texts: Is there a favoured mathematical model of bacterial growth?

texts:
One of the most regularly measured phenotypes in bacterial synthetic biology is growth. Anyone who does wet lab microbiology or synthetic biology will have performed a growth curve measurement. However, it is quite rare in synthetic biology papers for growth to be characterised using a mathematical model - even though growth curves are regularly shown in supplementary materials.
There are a plethora of growth models around - from basic logistic growth to the more biologically grounded Monod growth. I recently discovered the Richard's model which seems to be a more general form encompassing logistic, Gompertz etc. Is there a favoured model for the microbiology and/or synthetic biology community? Is there something holding the synthetic biology community back from regularly reporting growth characteristics of their cells?


texts: Do plants have preference for the form of nitrogen as nutrient?

texts: In the nitrogen cycle (ecology), it is usually described that plants can use nitrogen in the form of ammonium (NH4+) and nitrate (NO3-). Do plants prefer one form of nitrogen over the other?