texts: What is the advantage of using plant-derived antibacterials rather than bacteria-derived antibacterials?

texts:
So obviously we have a big problem with antibiotic resistance. Most of our antibiotics originate from bacteria themselves (or are synthetic variations on scaffolds which originate from bacteria). I have heard it asserted that using antibacterials derived from plants would lessen the problem.

One argument for the use of plants is that the bacteria from which we derive an antibiotic must themselves already be resistant to that antibiotic, meaning that the allele for resistance is already in the bacterial gene pool and when we exert a selection pressure by using the antibiotic, resistance will eventually appear among pathogenic species.

Another argument I have heard is that plants can provide a lot of structurally diverse metabolites from which we might discover new classes of antibacterials.

Is there anything else to this?

(I know I have answered my own question to an extent, but I am wondering whether there are any other good reasons to look to plants for the next generation of antibacterial drugs).

Thank you!


texts: Why do surface mole tunnels follow directly below the electric fenceline

texts: I have electric fencing enclosing five acres, and moles always seem to tunnel in a straight line just under the electric fence - are they following a force field? Can that be?


texts: Breakpoint resolution for copy number variation analysis

texts:
I am reading [1].
One limitation of the Read Depth approach is that "the breakpoint resolution is often poor". Which is the meaning of low-resolution breakpoint in this case?
Breakpoint is defined as the sequence breakpoint:

Examples of a structural variation include a large deletion, insertion, duplication and inversion. Each requires the DNA duplex to be broken and rejoined, and this creates a new sequence of bases at the rejoined sites, i.e. the breakpoints.
Sequencing the new breakpoint regions is a good way (perhaps the only way?) to demonstrate an inversion, which does not increase or decrease the amount of DNA.
Original sequence: 123456789
Sequence with inversion: 123765489
Breakpoint sequences are at 37 and 48

[1]: C. Alkan, B. P. Coe, and E. E. Eichler, “Genome structural variation discovery and genotyping,” Nature Publishing Group, vol. 12, no. 5, pp. 363–375, Mar. 2011.


texts:
In many spas and salons I have seen people place a cold cucumber on their eyes.
 I think this might be for coolness, but why a cucumber?
And Is it actually for coolness or for something else (like lightening of dark circles, etc.)?


texts: Action potential: why called "depolarization" when polarity is reversed, not removed?

texts: During an action potential, the voltage shifts from the resting potential of -70 mV, to +30  mV, to then fall return back to the resting potential again of -70 mV. This reverse of the polarity, what is the reason it came to be called "depolarization", as in, removed polarity?


texts:
There's a genus of plants known as Typha, or cattail.
They have seeds like of dandelion, that form thick heads. Such a head may be cut off from the plant and be used for, say, decorative purpose, but when the spring comes, seeds will spread out their 'hairs' and fly away. It looks like an absolutely dry piece of plant - no life in it - suddenly gets alive.

I suggest that it may be a daytime prolongation of a  that causes it to spread seeds, but I wonder if anyone knows what sort of cellular/biochemical mechanics is at work here.


texts: Why does deamination in the lagging strand lead to an increase in the relative number of guanine and thymine to cytosine and adenine?

texts:
My question arose from this article on Wikipedia on the GC-skew in bacterial genomes: https://en.wikipedia.org/wiki/GC_skew
As far as I understood, the lagging strand (the template strand), during replication, is more often single stranded than the leading strand (template), so it is more prone to mutations like deamination. Therefore, on the lagging strand (here, the one being the template to the strand formed by Okazaki fragments), one should expect more Ts and fewer Cs. Conversely, the strand synthesised by Okazaki fragments should have an enrichment of As and a depletion of Gs. Why does the Wikipedia article mention a increase in the ratio of (G+T)/(C+A)? I would expect an increase in the ratio of (T)/(C). I don't get the link with Gs and As.


texts:
How is the maxillary bone split in the Bolyerine Snakes described in T.H Frazzetta's "From Hopeful Monsters to Bolyerine Snakes?"

In T. H. Frazzetta, "From Hopeful Monsters to Bolyerine Snakes?" He describes boid snakes on the island of Mauritius as being unique among snakes in that they had a split jaw, connected by a joint. This was said to be an example of how continuous evolution could not be true for all cases, as what is the point of 1/2 of jaw, according to Stephen J Gould.

I dont seem to understand the pictures illustrated in the aritcle though, and how the maxillary bone is split and where it is connected to a joint. I could not find a legible picture of a  Bolyerine Snake described like this, if anyone could help with understanding it with a picture that would be appreciated.

I would provide the pictures, but I am not sure if that counts as plagiarism.

Citation:

Published by: The University of Chicago Press for The American Society of Naturalists,
Available from: http://www.jstor.org/stable/2459073


texts: Can two Hfr strains of E. coli conjugate?

texts: Genetics textbooks (and some internet searching) yield abundant examples of Hfr strains conjugating with F- cells, but these sources are surprisingly silent regarding the results of an Hfr encountering another Hfr strain. Will conjugation occur in both directions, or will it not occur at all? Similarly, can F+ cells conjugate with other F+ cells?


texts: Why haven't humans been able to make blood producing vats?

texts:
There are people in hospitals in life threatening circumstances that need blood packages, and they fully depend on blood donors' blood.
With our current technology, we have been able to "persuade" stem cells to differentiate into many kinds of cells or to replicate themselves, and even modified bacterial DNA to produce insulin. Why haven't we still made something that produces blood?


texts: Does the second law of thermodynamics cause aging?

texts:
What is the current understanding as to why organisms age and die? In the following explanation on Ask an Engineer, entropy is not even considered (despite it being answered by an engineer). Unless you consider

  accumulation of damage to an organism over time

as a result of entropy ?

In the end, is the eventual death of any organism a result of how the laws of universe? In the paper Aging of the brain, entropy, and Alzheimer disease, the author states that

  Increasing entropy, manifest through a complex network of interacting ARCs, is seen as the fundamental driving cause of neural and cognitive decline in the elderly

where the abbreviation ARC stands for age-related changes.


texts: Why high quality DNA should be between 10 and 20 kb?

texts:
On this website, they are saying that, when using a gel electrophoresis to assess DNA quality, :

  High quality genomic DNA should give a major band of 10-20 kb on the
  gel.

Why is that so? I thought it could be because of the size of the chromosomes, but chromosome X in humans is 156,040,895 bp, which is far from 10-20kb. So why is that threshold of 10-20kb? Is DNA breaking usually in chunks with that size?


texts: To what extent do domestic animals understand language?

texts:
Note: Please tell me to re-post this in Cogsci or pets if this doesn't belong here.

Hello All,

I want to know how dogs or other domesticated animals differentiate between normal chat and a command. Do they understand their master's language or body language?

If they understand the body language of the master alone, then how come they can do the same trick (in most of the cases) if some other person gives the same command?

And to what extent do they have this understanding, meaning how many words does a domesticated animal understand?


texts:
What is the length of gene when calculating TPM (transcripts per million)?
Assume I have a dataset matrix with k rows(each row is a gene) and n columns (each column is a sample), is there any way I could transfer the data set into TPM? Many thanks!


texts: Why don't my ears pop in the morning going through a tunnel?

texts:
I drive through a tunnel (morning and evening) on my normal work commute. In the evenings, my ears will pop going through this tunnel, but they do not pop in the mornings. There are actually 2 separate tunnels for the northbound and southbound traffic, but they are right next to each other, with the same elevation changes.

What is the difference as to why the ears only pop in 1 direction?

Here's a short video of tunnel


texts: Just a thought: the CO2 concentration is increasing . Due to a different but possible related phenomenon, the algal blooms are on the rise. We humans want to control both. But algae are the major source of O2. Could the rise of algal blooms in the rising concentration of be related CO2 ? I wanted to know if this would eventually be advantageous to the environment, even though algal blooms may be detrimental to some species and directly or indirectly to humans too?


texts: What, if any, is the difference between covalently closed circular DNA and plasmids?

texts: Are cccDNA (covalently closed circular DNA) and plasmids the same thing? What about DNA topoisomers?


texts: Why is this dry pepper fruit still "powered"?

texts:
Check out this photo of my pepper plant this cloudy morning: (click for full res)

Usually (and this can be seen on 2 and a half of the 4 fruits in this pic) the fruits are "disconnected" from the plant's juice flow when they're ripe. Then the fruit starts to dry. Yet the middle one in the pic is dry while its "cord" is still green (literally). Why does it not become dry like his fellows do?

There's also another interesting situation going on with the lower right fruit's "cord", which is half-dry. I wonder why it has been like this for a little over a month now without change.

The lighting conditions are pretty poor for this plant, so I use a 40 watt incandescent lamp for it and 4 other plants 24/7.

Please, excuse my poor vocabulary :)


texts: Confusion related to a term probe-by-background interaction

texts:
I was reading a paper related to bioinformatics where it uses the drug response on the cancer cells and the gene expression of the individual cells are studied to find any useful insights. Specially, using the gene expression of the cells a predictor of the drug response is created.

They have stated that just using the correlation between the gene expression and the drug response might not be a good predictor. But the genes interact through signaling pathways to drive a particular drug response.

What these guys have done is like used PCA on the gene expressions of the cancer cells to use the components which preserve the greatest variance.

Actually, I didn't get what they mean by probe-by-background interaction and how it is calculated.

Can anyone please explain. I googled for a while but didn't get it.

Here are some quotes from the paper where the term is used

  Towards this end, we have compared how well drug response can be
  predicted by simple statistical models, which either directly relate
  probe and background networks to drug response or consider
  probe-by-background network interactions.

  To generalize this approach, the term ‘probe’ could be
  replaced by individual transcript expression levels measured through
  other gene expression methods. Similarly, ‘background networks’ and
  principal components are used interchangeably. Generally, ‘background
  networks’ could be represented by any data reduction method that
  summarizes the expression of a gene network. We demonstrate that
  probe-by-background network interactions significantly enhance drug
  response predictions, over and above the predictive power garnered
  through utilizing individual probes and background networks alone.


texts: Are antihistamines considered to be psychoactive substances?

texts:
I have heard many times that the widely used antihistamines are not considered to be psychoactive drugs. Yet their impact on ones cognitive functions can be substantial. According to some sources, sedatives are also attributed being psychoactive, but not antihistamines. What is the difference?

UPDATE

Some links for the "cognitive effects" that I am referring to include hallucinations as well as drowsiness, anxiousness and irritability.

Besides that, it is well known that antihistamines cause drowsiness and sleepiness which are artificially altered states of mind because they are 1) not naturally-occuring, 2) have different mechanics and flow than their natural counterparts.

from experience I know these effects can be very strong, up to the state when one sees dreams while being awake. I can't find any scientific papers on that, but I have found many reports on the web and among people I've talked to.


texts: Why do my muscles move slowly when cold?

texts:
When my hands are cold, e.g. outside in the winter with no gloves for a while, their muscles begin to move slowly (assume I'm otherwise comfortably warm, e.g. dressed well but gloveless).

I don't seem to lose strength or endurance really, only maximum speed. Coordination is difficult and rapid repetitive movements are impossible, attempts instead lead to a continuous contraction (like normal, but the threshold is much slower). Of course normal function returns when the temperature is brought back to normal.

Why is this so? What is the correlation between lower temperatures and slower muscle response? Is it something with the neurons, something with the muscle tissue, or both? Is it related to blood flow (like when my hand "falls asleep" when circulation is cut off) or is it a property of the tissues themselves?


texts: I'm doing a lab soon and I need to find a way to measure fermentation rate to a relatively high degree of accuracy without using a specialized sensor. It should ideally be done with easy to find tools at home or in the classroom.


texts:
When considering how organisms store energy for later use, I was wondering what substance known in Biology is best for compacting the most energy in the smallest space(volume-wise).

With my (limited) knowledge, I would guess that it would be what we would normally call "body fat". However, I know I am probably not aware of most forms of stored energy, and I considered that perhaps substances like egg-whites may potentially contain more energy in the same amount of volume.

So, the question as in the title: What is the most condensed form of (stored) energy used in biology?

Alternatively, if there is no known "best": What would the leading competitors be?


texts:
I want to know the significance of sphingolipids in human.
I have learnt that sphingomyelin is the most significant type of sphingolipid in human.
Also that the sphingomyelin serves as a structural constituent of myelin sheath of nerve fibres.

Is that all? I need to clarify this. Please help me. Thank you


texts: How long can a human neuron live outside the body in a controlled environment?

texts: Have there been any experiments that have kept neurons alive (stationary), without preserving methods such as freezing? If yes, then how long were the cells kept alive for?


texts: How many hematopeietic stem cells (in percentage) does the bone marrow contains?

texts: I've found out that the body marrow of an adult weights about 5% of it's total weight. How much (%) of the bone marrow consists of hematopeietic stem cells and how much consists of other non-hematopoietic cells, i. e. "stroma" (%) ? I've also found that in adults, ~70% of bone marrow consists of adipocite cells.


texts: Why are nutrients from food absorbed more efficiently?

texts:
It seems to be common knowledge that micronutrients such as vitamins are more easily absorbed by your body when in your diet versus supplements such as pills.
I am wondering what the reasons for this are.


texts:
The Price equation describes mathematically the evolution of a population of units from one generation to the next.

  $\bar{w}\Delta \bar{z}$ = $Cov (w_i,z_i) $+$ E(w_i\Delta z_i)$

I would like to know how to actually employ the equation to some data. Perhaps a simple online "walk-through" type guide of the Price equation would help. It should simply show the calculation of the Price equation using numbers from an example population. For example, I'd like to see how the Price equation is applied to the following scenario:

  A population, $P$, of 5 individuals reproduces to produce population
  $P'$.

  The trait value of the $i^{th}$ individual is $z_{i}$ where $z_1$,
  $z_2$ and $z_3$ all = 1 and where $z_4$ and $z_5$ both = 2 and $\bar{z}$ = 1.4.

  Absolute fitness is $w_i$ for the $i^{th}$ individual where $w_1$,
  $w_2$ and $w_3$ all = 1, and $w_4$ and $w_5$ both = 5.

  Relative fitnesses, $\omega_i$, are $\omega_{z=1}$ = 0.077, and $\omega_{z=2}$ = 0.385.

  Thus the population $P'$ has $n$ = 13, with 3 individuals where $z$ = 1
  and 10 individuals where $z$ = 2 and $\bar{z}'$ = 1.769.

  $\Delta z $ is the transmission bias and is equal to 0 in this case
  (perfect transmission of the trait score $z$)

  The value $\Delta \bar{z}$ = $Cov (w,z)/ \bar{w}$ = ....

Here's an R script to create the above information:

# Define two trait values:
z1 = 1
z2 = 2

# Define two fitness values:
w1 = 1
w2 = 5

# Set number of units possesing each trait in P population:
n1 = 3
n2 = 2

# Create data
df = data.frame(c(rep(z1,n1),rep(z2,n2)),c(rep(w1,n1),rep(w2,n2)))
colnames(df) = c("z","w")

df$omega = df$w / sum(df$w)

n_P = length(df$z)
    n_O = sum(df$w)
z_P_bar = mean(df$z)
    z_O_bar = sum(df$w*df$z) / sum(df$w)
omega_z1 = mean(df$omega[df$z==z1])
omega_z2 = mean(df$omega[df$z==z2])

# Parental population size:
n_P
# Offspring population size:
n_O
# Parental mean trait:
z_P_bar
# Offspring mean trait:
z_O_bar
# Realtive fitnesses:
omega_z1
omega_z2


texts: So we know that there is a first gene therapy drug in the market out there called Alipogene tiparvovec to address  lipoprotein lipase deficiency (LPLD) at a genetic level. Does this genetic drug target all cell types (except germline) that expresses the LPL gene in the human body or simply the parenchymal cells that process fat? I have not been able to find information specific to Glybera.


texts:
Are there any completely autotrophic species of fungus?

If so, what species are they? What ecosystem do they live in? Some answers from Quora state that a fungus can never be autotrophic, but why is that?

Thanks for your time!


texts: Does the Jungian notion of collective unconsciousness have any legitimacy in the light of modern neurobiology and epigenetics?

texts:
Carl Jung has long ago proposed a rather controversial notion of collective unconsciousness [1, 2, 3],

  a form of the unconscious (that part of the mind containing memories
  and impulses of which the individual is not aware) common to mankind
  as a whole and originating in the inherited structure of the brain. It
  is distinct from the personal unconscious, which arises from the
  experience of the individual.

While the complete original formulation of the idea may be interpreted as unfalsifiable and hence unscientific, suppose that we try to redefine it to some more modest idea, e.g. a set of inheritable subconscious memories, impulses and reactions present in populations/groups, with some expected degree of variation.

Now, it has been shown that memories reside in specific brain cells [4]. What is also known is the direct impact of environment (which - as far as I understand it - also includes our thoughts, feelings and expectations) on gene expression and epigenetic inheritance. In the light of these insights, could the notion of collective unconsciousness be revitalized and interpreted in some non-trivial way that could be used to better understand the way we dream, feel, identify with characters in stories etc.?

In other words, do new discoveries in neurobiology, evolutionary biology and epigenetics shed any new light on Jung's writings (e.g. timescale for such structures to adapt between generations etc.) and perhaps confirm some of his ideas? If not, could experiments be performed that would provide some new insights? Or is the idea so trivial at its core that basic evolution is enough to explain it in its entirety?


texts:
In a microarray, which one is called a target and which one is the probe? the one that is added later , is that the probe or the one present in the slots of the microarray, that is the probe?
(I have not studied biology since last 8 years and now I am going through it because I need it for my research. So if the question seems to silly, forgive me)


texts: Can anyone explain how contraction of the ciliary muscles causes relaxation of the zonules? Please explain it anatomically i.e. the attachments of ciliary muscles and its relation with the accommodation process.


texts: Why did Eukaryotes evolve to have linear DNA and not circular like Prokaryotes? What are the pros and/or cons?


texts: How does the body really react to exposure to the vacuum of space?

texts:
I've seen sci-fi movies where the effects the body being unprotected in outer space are wildly different. In one movie, a guy radios for someone who's been ejected into space to breath all the air from his lungs immediately. In some movies, eyes are pulled from sockets. In others, ice crystals form, and the eyes begin to look a bit red... Sometimes the exposed person is a goner right away, sometimes they're shown to last for a minute or more. The Hollywood portrayals of space exposure just vary tremendously.

So I'm curious, what really happens to the human body in the vacuum of outer space?


texts: Pitch perception - why is the missing fundamental not directly detected in the cochlea?

texts:
I'm learning about pitch perception, and learned about the case of the missing fundamental.

In the main image in that wikipedia page, it seems like the bottom graph, with the fundamental frequency and its second harmonic removed, that the wave is still very periodic at 100 Hz. Since the Organ of Corti has some area which should be excited when there's a sound wave of frequency 100 Hz, why does this sound wave, which seems periodic at 100 Hz, not directly excite that region of the organ?

Can someone explain the workings of the inner ear and detail on why the missing fundamental does not activate the cochlea? Reversely, how can 100 Hz be heard when the cochlea is not even activated at that frequency?


texts: How do PrP mutations lead to prion disease?

texts:
My understanding is:

The PrP gene in human cells is expressed as both PrP-c (normal protein) and  PrP-sc (prion disease protein). This happens post transcriptionally, that is, the normal and the diseased protein are not distinguished based on genetic mutations, rather they are synthesized based on the same gene, but differ in their tertiary structures, which makes their functions also different.

If the amino acid sequence of both proteins is the same (same gene), then what determines whether the synthesized protein will take the disease-causing tertiary structure or the normal one? Is it due to post-translational modifications?

And finally (I apologize for advance for multiple questions): how do prions, which are void of nucleic acids (being proteins), integrate into the genome of a newly infected host by reverse translation, and become a familial disease?


texts: My eyes were accidentally exposed to high infrared radiation and they hurt, why?

texts: My eyes were exposed to high amounts of infrared radiation. They hurt - why?


texts: How can a drink contain 1.8 kcal energy while 0 g fat/carbs/protein?

texts:
How is it possible that the Red Bull Zero contains 0 gramms of fat, carbs and protein, but it still has 1.8 kcal of "energy".
I always thought that the human body can gain energy only from 3 kinds of nutrients: fat, carbs and protein. Is there a 4th kind? Or they just display an energy value that's not accessible to the body?


texts: What causes the localization of myoglobin in turkey to regions of muscle tissue?

texts: I've read that myoglobin localization is responsible for the darker colour of leg muscles in turkeys. Why does this localization occur in terms of any of cell biology, molecular biology, or biochemistry? I'm not looking for bigger picture explanations at the levels of physiology or evolution, although I understand that they'll be connected to this question.


texts: How come degraded eyesight still holds with a mirror?

texts: When you use a mirror to look at something, you can position it at an angle arbitrary to your face and still look at an object far away. My question is, for degraded eyesight, how come the picture is still degraded in the mirror? Is it because of an imperfect mirror? Is it theoretically possible to have a mirror that when looked at an angle with perfect scattering to give you better vision than without the mirror, just looking regularly with degraded vision? I am just wondering, it seems like a photonic process, but i don't know enough about the eyes to turn them into any sort of functional system


texts: What happens when a genome is shorter than the other?

texts:
Say there were 2 creatures of the same species. Creature 1 has a longer genome than creature 2, it may be just a few base pairs, but what would happen when the genes were crossed to create creature 3 (via Sexual Reproduction)? Do the genes know where to match up or are there genes that end up being corrupted during this process?

Thanks in advance


texts: We all know that DNA acts as a genetic molecule. Does DNA have any other function in the cell other than being a genetic material and carrier of information?


texts: Do cancer cells respond to electromagnetic fields? If so, can someone please provide reliable information as to how they behave in such fields? Do you suppose the growth rate to be affected in any way ?


texts:
Hey guys I want to ask why I can't get any binding interaction if I use TRIS-NaCl buffer for protein quantification using aptamer as its bioreceptor. But I can see the binding interaction if I use PBS buffer
The procedure step for my experiment :
1.) Self Assembled Monolayer (24-48 hrs) - NHS/EDC Activation (wash with acetate) - Streptavidin (Acetate buffer) - wash with acetate - wash with TRIS - ETH Blocking - wash with TRIS - Aptamer biotinylated (TRIS buffer) - Protein (TRIS buffer)
all washing buffer are using TRIS or PBS
And down below (my other method) I tried to exchange the buffer from PBS to TRIS after aptamer injection
2.) Self Assembled Monolayer (24-48 hrs) - NHS/EDC Activation (wash with acetate) - Streptavidin (Acetate buffer) - wash with acetate - wash with PBS - ETH Blocking - wash with PBS - Aptamer biotinylated (PBS buffer) - Buffer exchange (PBS to TRIS) - Protein (TRIS buffer)
I can see my aptamer signal in 1st and 2nd method, but still no binding occurred between my aptamer and my protein in TRIS buffer.


texts: If DNA changes over time, how is it that forensic DNA gathered decades ago can be matched to a person today for solving crimes?


texts: How are DNA polymerase error rates measured?

texts: It is well known that the first DNA polymerase, Taq, is quite error prone. Newer generation commercial enzymes that have either been isolated from different thermophile species or have been improved by recombination are less error prone. How are these error rates compared? For instance, if this is done by Sanger sequencing, the average signal will dominate in reading the output and so it will be very unlikely to pick up on errors by this method.


texts: Why is beta actin commonly used as a control in Western blots?

texts:
It is about the western blot question. The paper:http://www.sciencedirect.com/science/article/pii/S1931312813001145.
In the western blot experiment in this paper, they use beta actin as control. And also I saw other research paper also use beta actin as control. So why is beta actin used, not other gene? is it because it expressed in all different kinds of cells?


texts: Why is living muscle tissue seemingly able to restore its shape under force, while dead tissue is not?

texts:
When I press my finger, even with relatively little force, into beef or chicken (say, at a grocery store), the indentation remains.

When I poke a cow with my finger, the indentation does not remain. When I squeeze my own arm, even with the same (or greater) amount of force used to alter the shape of meat with my finger, my arm remains the same shape afterwards.

What is the difference between dead and living muscle tissue, with respect to mechanisms that allow it to maintain its shape? Does living muscle tissue somehow actively maintain its shape while dead tissue cannot? Is it something more passive, such as a breakdown of something in dead muscle tissue that makes it more malleable (and if so, what)?


texts: What factors govern the variable age of onset in Huntington's Disease?

texts:
"Huntington's disease (HD) is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric problems." As we all know, this genetic disease exhibits a generally late age of onset. It has been shown that a increase in the number of CAG repeats in the hungtingtin gene is negatively correlated to the age of onset of the disease. However, patients having a  particular number of CAG repeats still have an extremely variable age of onset, which leads to believe that other factors are contributing to the Huntington phenotype.(reference)

 (reference)

What other genetic or environmental factors have been shown to vary the age of onset of Huntington's disease?

References

Andrew, S. E. et al. The relationship between trinucleotide (CAG) repeat length and clinical features of Huntington’s disease. Nature Genetics 4, 398–403 (1993).


texts: Why Can Varied Species Live Together in Particular Ecosystems?

texts:
Consider the following question:

  The Piney Woods of Eastern Texas is home to a wide variety of organisms ranging from the grass Longleaf Oats to coyotes. Which of the following best explains why these varied specifies can live together in this particular ecosystem?
  A.) Each species lives in a slightly different habitat B.) Each spices occupies a different niche C.) Each species functions at a different trophic level D.) A and B   E.) A, B, and C

I chose answer choice E with the reasoning that: Oats and Coyotes do not share the same habitat; they occupy a different niche -- Coyotes eat organisms, oats use photosynthesis; coyotes are at a completely different trophic level when compared to oats -- oats being primary producers. The answer choice E however is incorrect and I'd like to know why and what the correct answer should be. Is there a flaw in my logic?


texts:
I am trying to understand the meaning of the dominance coefficient. I'll be more specific to what I don't understand, in a moment.
Let $A_{11}$, $A_{12}$ and $A_{22}$ be genotypes with fitnesses $1$, $1-sh$ and $1-s$ respectively. I can understand the meaning of the selection coefficient $s$ as its sign clearly determines which allele is more advantageous.
Though, I cannot figure out the meaning of the dominance coefficient $h$. I understand the following:

if $h>1$ we have underdominance i.e. both homozygotes are more fit than the heterozygote
if $h<0$ we have overdominance i.e. the heterozygote is more fit than the homozygotes
if $0 < h <1$ we have that the heterozygote is only more fit than the deleterious homozygote

The last point is called incomplete dominance as opposed to complete dominance in the cases $h=0$ and $h=1$. Here, I'm having trouble to understand how this is related to dominance. I mean, I can clearly state that $h=0$ implies that the fitnesses of $A_{11}$ and $A_{12}$ are equal, but why does this imply that $A_1$ is dominant and $A_2$ recessive (the situation $h=1$ is symmetrical of course)?

For this terminology, I'm referring to Gillespie's Population Genetics: a concise guide. A table resuming what I'm talking about is also on Wikipedia here.

I'd like to point out that I'm not a biologist, but just a mathematician, so it may be something simple in how dominance works that I'm missing. Also, for the same reason, please, forgive me if I have worded something not appropriately. Thanks to those who will help.

EDIT: I'm not asking what the biological process behind dominance is. I'm just asking how $A_{11}$ and $A_{12}$ having the same fitnesses (which, for me, reads as having the same chance at surviving) relates to $A_1$ being dominant. As it was pointed out in the comments, this is the definition of dominance. Though, I thought that dominance of one allele means only which phenotype will prevail in the heterozygote case and I cannot find the relation between the two definitions.


texts: Feet size correlated with testosterone in women?

texts:
Do females with bigger feet have more testosterone? Examples:

1.Regular-sized women with larger than average shoe size

2.Taller women who tend to wear larger shoe sizes more often than not

I ask because some people say that when women feet get bigger they resemble men's feet more. I ask if this such resemblance is indicative of testosterone higher naturally in these women vs. women with smaller feets. I hope someone can understand and apply these methods to an answer.

For example my sister have bigger feet (size 10 in women's Canada) and people have always told her, especially family, that her feet look like a guy's feet/structure more because they are bigger.

Like the genes that mold the bone structure and design of the foot could having higher test. impact the feet and give the women with larger types feet that people say are more masculine more natural test?


texts:
I am making a T1 weighted phantom for an MRI project. It consists of distilled boiling water, 7g/L agar, 10g/L NaCl and 1g/L CuS04. As the phantom cools it will get a jelly like texture. What I would like is for the phantom to be as homogeneous as reasonably possible when it solidifies. What do you think is the best way to do so?

I was thinking of having the mixture on a vibrating plate, or maybe a centrifuge or even just inverting the mixture at regular intervals. Any ideas would be greatly appreciated.


texts: What species are these juvenile birds found at São José dos Campos, Brazil?


texts: Quantitative Physiology Textbooks Recommendations?

texts:
I am currently completing a 2nd year (UK) Mamamilian Physiology Module and a Neuroscience Module. However, my degree is also 40% Maths and Statistics. So in order to learn the content better, I am thinking I may be more suited to a quantitative first explanation before the qualitative description.
I am asking here as I don't want the biology to be glossed over as I am being assessed by Physiology Professors not my Statistics Professor


texts: Why was the evolution of large, slowly reproducing organisms preferred?

texts:
One of the very basic facts that Darwin pointed out was about the life span of organisms. Organisms with smaller lifespan reproduce quickly and hence variations are produced faster. This helps in faster evolution.

One of the main goals of living organisms is to reproduce, this fact being the backbone of neo-Darwinism.
For organisms with longer life span, say humans, the amount of time required for new generations to come up, as well as the energy requirement is high, much higher if compared to bacteria. Then why did evolution of complexity arise if bacterial life forms could survive in harsh conditions and reproduce and mutate faster?


texts: DNA-DNA cross-linking with formaldehyde?

texts:
The 3C (chromosome conformation capture) technology for studying chromatin 3D organization starts by a cross-linking step using formaldehyde to find segments of DNA interacting. In my understanding the cross-linking happens only between the DNA and proteins forming a DNA-protein-DNA complex. The "only" is from a DNA stand-point as of course protein-protein cross-links will also occur.

Can formaldehyde cross-link two double stranded DNA molecules? Is the 3C approach also capturing direct DNA-DNA interactions?

I looked at the literature, especially Dekker et al. description of the method, but couldn't find this information. Thanks.


texts: Do DNA viruses have their own DNA dependant DNA polymerase?

texts:
There's an exception to the rule that all DNA viruses need to get to the nucleus in order to replicate. Poxviruses do not require to get into the nucleus because they can make protein from their very own DNA-dependant-RNA-polymerase.

That is fine. But then, how do they make new DNA (for daughter virions)? Do they also have their own DNA-dependant-DNA-polymerase?

So here are my questions -

Does the pox virus also have its own DNA-dependant-DNA-polymerase? If yes, is it unique in having so?
How about other DNA viruses? The rule that they need to get into the host nucleus - is it for making protein using the host DNA-dependant-RNA-polymerase or for replication using the host DNA-dependant-DNA-polymerase? Or for both?
Do all other DNA viruses need to get integrated into the genome to be able to replicate, and do so along with the cell? Are there instances where the host DNA-dependant-DNA-polymerase is expressed at times other than the cell's S-phase?
Are there viruses that replicate inside the cell's nucleus without being integrated into the genome?

I know that's a lot of questions! Hope someone does help.

Note: Discussion limited to those viruses infecting eukaryotic cells. Also excluding Hep B (hepadna virus).


texts:
ery bug 1]1

What insect are these? Found them indoors. No wings, just crawling on the walls.


texts: Why are birds have balls in the form a cork screw i dont have the scientific name

texts: Why do birds have penises in the form of a cork  screw?


texts: What organ can be conserved outside of the body for the longest time and still function when reimplanted?


texts: How much weight/volume do microbes occupy within the human body?

texts:
Microorganisms constitute the bulk of all the biomass on Earth. I weighed myself yesterday, and wondered how much less I would weigh if I were completely free of bacteria and microbes, inside and out.

Approximately how much weight and volume do microbes occupy within the average human body? How were these values obtained?


texts: Why only female mammals have well developed mammary glands?

texts: In course of evolution (possibly), mammary glands became vestigial in male mammals, but became fully developed in females. Is there any plausible explanation for this characteristic?


texts: Which species has the highest proportion of homosexual individuals?

texts: Are there more homosexual individuals in ducks, humans, or some other species?


texts: I need to express a protein in vitro but I don't know where to start.  I will likely do a  T7 transcription protocol but for translation I am not sure what to do.  Are there any good kits?


texts: When are neuropeptides loaded into vesicles?

texts:
It is well known that small neurotransmitters like monoamines (dopamine, serotonin, etc), acetylcholine, glutamate, etc are loaded into vesicles at the axon terminal. Stated differently, synaptic vesicles,SVs (which are the name of the vesicle type that store small neurotransmitters), are made locally within the axon terminal, and then ultimately loaded with small neurotransmitters.

However, I cannot seem to find when larger molecules, like neuropeptides, are actually loaded into their vesicles. I know that neuropeptides are made in the soma, but I am unsure of when they are loaded into their vesicles.

Are neuropeptides loaded into their vesicles at the synapse?

" Small-molecule neurotransmitters are synthesized locally within the axon terminal" https://web.williams.edu/imput/synapse/pages/I.html

"As a rule, the synthesis of small-molecule neurotransmitters occurs within presynaptic terminals" https://www.ncbi.nlm.nih.gov/books/NBK11110/

"SVs are made locally at the terminals and are regenerated after exocytosis"  https://www.sciencedirect.com/science/article/pii/B9780080450469013929


texts: How many mRNA strands are in a single dose of the COVID-19 vaccines?

texts:
I realize there are several different mRNA vaccines. I would be happy to know the ballpark figure for any of them.
As a follow-up, is it known about what percentage of injected mRNA strands are successfully translated into proteins?


texts: Is it possible to distinguish between coding and template strands from the sequence?

texts:
Let’s say you have the following DNA sequence fragment:

5’-ACCAGTACTTCGT-3’
3’-TGGTCATGAAGCA-5’

Is there any way to determine which strand is the template strand and which is the coding strand for RNA synthesis solely from the above information?


texts: What would happen if Carbon-14 was in a glucose molecule and decayed into Nitrogen?

texts: This interested me because of Melvin Calvin's experiment with photosynthesis where he used radioactive Carbon-14. If a plant used it as a reactant to make glucose, and that Carbon-14 decayed into nitrogen, what would happen to the molecule?


texts: Plant cell question in age 12 science test

texts:
Can anyone help me answer the questions in the attachment about plant cells. It was a question in my 12 year olds science exam. I'm baffled as I think he has given a good knowledgable answer but it wasn't awarded a mark.

Kind Regards
Matthew


texts: Why roots have radial vascular bundles while stems have conjoint?

texts: Why not the whole plant has the same arrangement of vascular bundle,  why there is a difference of arrangement in roots and stems (radial in root and conjoint in stem) ,  what is the purpose of this difference?


texts: Why does the stomach ache if you take a brisk walk after lunch or dinner

texts: After eating your lunch or dinner, if you take a brisk walk, most of the time your stomach aches. Why does that happen? What happens with respect to the body metabolism?


texts: Can a person be infected with Polio even after vaccination in childhood?

texts: We know that a person develops antibodies by active immunisation after the administration of vaccines (either in dead form / live attenuated form). Is there any chance of developing the same disease in immuno compromised persons after reaching adulthood?


texts: Are there available fluids that can be used in place of blood to facilitate oxygen and carbon dioxide exchange during major surgery/trauma?

texts: Are there any available fluid alternatives that can be used instead of blood replacement that adequately exchange oxygen and carbon dioxide?


texts: What species is this orange and black caterpillar from Costa Rica?

texts:
Does anyone know what type of caterpillar this is? I don't know much about them. Pictured it in January in Costa Rica cloudforest (Monteverde) and am using it in a speech for visiting Costa Rica.

Size about 3,5-4 inches.


texts: Identify this black dragonfly with a bright bluish-white band around its body

texts:
I took these photos around noon in late July in Hsinchu county Taiwan. This particular stick in this particular pond is visited by many dragonfly species. This one was very high energy and nervous but taking my time and waiting for it to return each time I spooked it I eventually got almost (but not quite) close enough to take a decent photo with my phone.
Its body is about 5 cm long and mostly jet-black. However it has a bright, solid white or blue-white band about 1 cm long behind the fat part of it's body along the long "tail section".
I'm showing the two best photos below, for the darker one I lowered the brightness of the photo on my phone before taking it so that the band wouldn't be saturated but it is still extremely bright. It may in fact be slightly blue-hued or that could be an effect of the phone's camera.
Is it possible to identify this particular species of dragonfly?


texts: How can you test what color different people perceive?

texts:
If I would show someone a yellow object and ask them, "is this object yellow?"
 That person would say "yes".

But I could never know if my perception of the color yellow is the same as that other person's.
Because he or she could actually be seeing, what I know to be the color green.
But then tells me that its the color yellow because that has been taught to him or her from young age.

So how can you test if people are really seeing the same color?
(originally posted this question on physics.stackexchange but was advised to try it here)
https://physics.stackexchange.com/questions/48731/how-can-you-test-what-color-different-people-perceive


texts: What are good techniques for determining direct maps of proteins?

texts:
I am looking for which techniques to explore to determine electron density maps (or Fourier maps) for a protein (possibly using an assumed model).

In particular, I want to avoid techniques that create difference maps like Fo - Fc, and I think this means I also want to avoid 2Fo - Fc or other types of "sigma_A" maps, which all (I think?) contain data indicating the difference/discrepancy between observed and modeled densities. I believe what I am referring to is a "direct map."

While I'm open to techniques that are informed by a candidate model, I don't want F_calc to show up in the actual output. Also, I'd like to reduce model bias as much as possible while still arriving at a direct map (assuming that is the correct nomenclature).

I've seen references to "Iterative OMIT" and various other "OMIT" maps, but could not determine whether those gave the output I'm looking for.

Ideally, I'd like to use techniques that are implemented in open-source libraries, though that may not be an absolute requirement.


texts: What does the MAF/MinorAlleleCount mean?

texts:
I'm not sure why reporting the second most frequent allele is helpful?
what is the Major allele?


texts: Conversion of ATP to NADH without creating a proton motive force?

texts: Is it possible to convert ATP into NADH and vice versa without first creating a proton motive force? If so by what mechanism is it done?


texts: Why does cold kill humans but not bacteria?

texts: Bacteria can continue like nothing happened after being exposed to low temperatures why doesn't this happen to humans as well? Why can't our metabolic machinery continue as normal?


texts: What is the maximum distance for an argentine ant (Linepithema humile) trail?  I imagine that there is some point where the ants are unable to make the return trip either through exhaustion or from the chemicals of the trail failing somehow.


texts: Why is it difficult for germs to jump species?

texts:
If you haven't watched CGP Grey's video Americapox: The Missing Plague, I suggest you watch it. It's an excellent video.
One assertion he makes is that "germs jumping species is extraordinarily rare [...] being the patient zero of a new animal-to-human plague is winning a terrible lottery."
Why is this true? Why is it so rare for a germ to move from a cow's body to a human's? Is it because it can't travel that distance while remaining alive? Is it because the human's immune system will kill it? More details will be appreciated.


texts: What effect does a bat's echolocation have on other bats?

texts:
Bat echolocation is a perceptual system where ultrasonic sounds are emitted specifically to produce echoes. By comparing the outgoing pulse with the returning echoes, the brain and auditory nervous system can produce detailed images of the bat's surroundings. This allows bats to detect, localize, and even classify their prey in complete darkness. – Echolocation, Wikipedia

Furthermore, we read that:

  [ . . . ] these bats contract their middle ear muscles when emitting a call, so they can avoid deafening themselves.

So far, so good. But this gives rise to two questions I've been challenging with. (And unfortunately I seem not to be able to find the correct search terms and I don't get relevant results)

Imagine two bats close together, flying in a distance of, say, 1 meter from each other. As we know, both echolocate in order to perceive the whereabouts of their surroundings. Bat #1 emits ultrasonic waves, but contracts its middle ear muscles so it won't get hurt. I imagine these two bats are close enough to each other for the waves to be harmful to bat #2's hearing as well.

Hence, two problems arise

Either the waves aren't harmful to the other one (I'd love some calculations on this, or hints on how to do some myself) or something's happening to bat #2 that doesn't let the ultrasonic waves damage its hearing. Certainly bat #2 isn't supposed to know when #1 will emit those waves, so what is happening?
Won't the waves bat #1 has emitted affect the waves bat #2 will emit? So, won't this affect bat #2's perception? We've seen many bats flying together in real life with [maybe seemingly] no trouble visualizing the surroundings, so this mustn't be the case, but why?


texts: Help to identify this large, slow-growing mushroom?

texts:
Here in my backyard in Southern California, there appears to be this relatively smooth, mottled-colored dome-like structure a little larger than a chicken egg in the dirt. Can anyone identify it? Is it some sort of insect nest or a multicellular fungus?

Edit: After a couple weeks, I've observed some changes. It appears as though this is definitely a fungus and it has been growing taller out of the base. I also see a few feet away something that looks a little different, but not that different, which appeared even at first to be more mushroom-like. Right now the closest thing I could find online is something like a Shaggy Mane. Here are the new photos:

Edit #2: It's been about three more weeks, and the fungus has continued growing larger. Also I am pretty confident that the second one is also the same species. Both have been growing longer and have started to crack at the top.


texts: Photographed in south east Brazil in the Atlantic rainforest during October 2017


texts: Is there a system biology approach to compare pathways or famillies of proteins from an evolutionary point of view for the same organism?

texts:
I would be interested to know if there is a method/analysis or a set of methods to compare two groups of pathways or families of proteins.

I would specifically be interested by a system biology approach which takes all the components of the pathway or family of proteins. I would like to know if there is a method which can not only compare the similarity, homology, divergence and convergence of a family of proteins (like ribosomal proteins) between species but also between groups in the same organism.

For example I would like to compare the molecular components of vesicular trafficking pathways to the molecular components of non-vesicular pathway in the same organism saccharomyces cerevisiae (yeast).

I would greatly appreciate your suggestions.


texts: How to compute the regression of individual fitness on individual phenotype

texts:
Consider a population structured in groups of two individuals. Individuals' interactions follow an additive prisoner's dilemma:

\begin{array}{c |c |c|}
& C & D \\
\hline
\text{Cooperate (} C \text{)} & b -c & -c \\
\hline
\text{Defect (} D\text{)} & b & 0 \\
\hline
\end{array}
where $b$ is the benefit and $c$ is the cost. The payoffs are to the player on the left. I need to calculate  the regression of individual fitness on individual phenotype, $\beta (w_i, p_i)$, where $p_i = 0$ if $i$ defects and $p_i = 1$ if $i$ cooperates. Note that I need to calculate the regression within groups rather than between groups.

I thought that the right way of calculating $\beta(w_i,p_i)$ would be to vary the strategy of the focal individual while keeping the strategy of the other individual constant (my thought was that the other individual becomes the environment for the focal individual). Because switching to cooperation causes an individual to lose $-c$ in fitness (if we keep the strategy of the other individual constant), I thought that $\beta(w_i,p_i) = -c$. But, to my surprise, $\beta(w_i,p_i) = -b -c$. To show why, McElreath & Boyd ("Mathematical Models of Social Evolution", p. 242) draw the following graph:

Let $V(X|Y)$ be the payoff of individual $X$ when it interacts with $Y$ (in other words, $X$ is the focal individual; $Y$ is the other individual). I understand that McElreath and Boyd calculated the regression coefficient by computing $V(C|D) - V(D|C)$ --- as opposed to $V(C|C) - V(D|C)$, where you keep the strategy of the other individual constant. My question is why this is the right way of calculating $\beta(w_i,p_i)$.


texts: I have seen this tree in Spain and Portugal. Its leaves and bark bring to mind the American Sycamore or London Plane Tree, but not exactly. Also, it has three spherical fruits, an arrangement I am unfamiliar with. Like an idiot, I left my tree identification book at home and the Internet has failed to satisfy my curiosity in this matter. Any help would be appreciated.


texts: What is the name of this South India plant?

texts:
Location: South India.

Month: June.

Branches of the tree:

Lower part of the Plant:

Plant's leaf:

Whole plant:


texts:
E. coli has a generation time of about 20 min, and a single CFU will generate a colony a few millimeters in diameter after 16 hours of incubation.

Is this the upper limit? How much faster can bacteria grow? How much faster can colonies grow?


texts: What is the non-local impact of a large-scale destruction of coral reefs?

texts:
I'm reading today that the "bleaching" of coral reefs is progressing with unanticipated speed. Bleaching is occurring at a scale which was previously believed to be decades in the future.

Bleached corals, according to the article in the New York Times1, have shed their symbiotic algae in order to protect themselves from toxins the algae produce when the water temperature rises above a certain threshold. If cooler temperatures are not restored quickly, the corals will die. This has happened with many affected reefs in the past and seems likely with the latest wave of bleaching too, given the apparent long-term increase in global water temperatures.

Even if the article does not say so directly it appears to me a distinct possibility that most coral reefs will simply disappear from the planet within just a few decades.

What impact will the disappearing of the coral reefs have on the oceans and the life in them, and ultimately on the whole planet? We know that reefs are the core of a complex and rich ecosystem. Which plants and animals outside the immediately affected areas depend on it? Are there migratory species who lose the reefs as a seasonal base? Which food chains will be interrupted, or over-provided? Do coral reefs have other functions like filtering, causing or reducing turbulence, influencing currents? Have there been studies or simulations which try to assess the global consequences?

[Edit]: I know the question is very broad. I'd be happy about answers to just one aspect. Specifically I'm interested in effects which are not obvious and/or have not been broadly publicized. Links to scientific publications would be awesome. Maybe somebody is working in the field, or knows somebody?

For example, affecting migratory species (fish or birds) may have unexpected consequences in otherwise unrelated parts of the world, similar to the effect of disappearing wetlands on migratory birds.

I also think it's possible that non-reef fish which are important food sources directly or indirectly depend on coral reefs. Are there specific examples?

I'm less interested in answers concerning species just living around the reef because cause and effect (though significant) are obvious.

1Which refers to the original study in this nature article.


texts: Is there any evidence of increased life expectancy for animal species?

texts: Life expectancy for human has significantly increased during the last century or so. We all know that there are many reasons that are not linked with "evolution", but I am wondering if such change in life expectancy has been observed "naturally" (not counting animals in zoos or domestic ones). Does evolution favor long lasting individuals?


texts: Can Allergy and Auto-immune diseases be the signs of hyper-vigilant immune system?

texts:
Allergy sufferers are much less likely to get some types of cancers. Theories regarding  allergy - cancer link are mixed.

Many say it is due to hyper-sensitive immune response.  But the correlation between allergy and lowered glioma risk is also difficult to explain, due to blood -brain barrier.

However there was one interesting theory, saying that, allergy is an evolutionary anti-cancer protection. Allergy sufferers simply do not let some of the carcinogens to come into their body.

I am computer engineer. When we setup a protection at a system (antispam, antivirus, firewall) there is  sensitivity level that we have to select.  Higher sensitivity offers better protection but also results in more false positives.  However not all false positives are due to higher sensitivity. Some can simply be due to faulty protection system.

So my question is,  can  allergy or auto-immune diseases be sign of high-sensitive immune system which will have advantages and  disadvantages  or just a sign of simply faulty immune system which will have only disadvantages?


texts: Does estrogen increase muscular growth in females?

texts:
Regarding humans it is said that most psychological effects caused in men by testosterone are caused in women by estrogens. There are many studies on that, particularly regarding temporary shifts of hormone levels: Ovulatory shift hypothesis. Also, there are some studies (and possibly controversial) claiming such differences between individuals.

But this made me think if there are any similar physiological diffences caused by estrogens. It's known that in males testosterone affects muscular growth, which means higher testosterone levels will make it easier to gain muscular weight. So, I ask if higher estrogen levels in females affect muscular growth.

While this question is regarding humans, studies about other primates also can be acceptable.


texts: Is it possible for neurons themselves to manifest cancerous behavior?

texts:
From what I understand, one form of cancer is a faulty gene responsible for the programmed death of a cell.

Not long ago, popular wisdom used to say neurons don't regenerate. However that is no longer believed to be true, if I am to believe what the internet says. For me, this begs the question: can neurogenesis result in faulty death genes which in turn result in overgrowth of the number of neurons? Would those neurons be functional? And if so, if theoretically such a brain could be artificially sustained without a body, would its growth be beneficial (in terms of intelligence)?


texts: How to distinguish the Ct of the target gene from the Ct of the housekeeping gene? (very basic qPCR question)

texts: I will do a qPCR experiment for the first time, and I have a bottom-level question to ask. I know that for normalizing the quantity of your target gene you have to add an endogenous control, like a housekeeping gene, in your qPCR sample, and then you subtract the Ct of the housekeeping gene from the Ct of your target gene. However, since the same SYBR green fluorophore is used to quantify both the target gene and the housekeeping gene in the same sample, how do you know which Ct is from the target gene and which one is from the housekeeping gene?


texts: What do these novel splicing sites mean?

texts:
I'm sure that the anwser is obvious for some of you but I just endend my internship where we found novel splice junctions (junctionseq; RNAseq data) (see the attached file) and I have some difficulties with splice junctions.
I understand that reads can map in the junction of 2 exons (which can be linked to quality assesment) and that comparing 2 conditions, we can find groups of exons more "associated" but I dont understand :

How a novel junction can be discovered in a previous junction (sub1), or behind the last exon of a gene (sub2) and thus, what can be the consequence(s)


texts: Are all single-celled organisms Bacteria?

texts: I read that "Bacteria are one-celled organisms that can multiply by division", are all one-celled organisms bacteria or are there any more narrow definitions?


texts: Can plants be grown using lights in the home?

texts:
Plants need sunlight to grow, mainly the blue and red wavelength of the sunlight . The lights used in homes are also white light, it will also have red and blue wavelength of light.

So , can they be grown in such lights perfectly?


texts: Hydroxyapatite is the main component of tooth enamel. It contains phosphorus in the form of phosphates, pyrophosphates etc. that are found to exhibit the the property of phosphorescence. But why don't the teeth glow in the dark ?


texts:
I recently took pictures of Spotted doves (Spilopelia chinensis) during their courtship. The one on the right, is large with a off-white breast and the one on the left is comparatively small with dingy reddish white breast.

My professor and I presumed that the one on the right is the male and the other is the female. The larger one mounted the other during cloacal kiss.

I've checked Wikipedia and other sites which seem to copy Wikipedia, they say that the species does not show sexual dimorphism. On the other hand, this website claims that there is a difference.

Does it show sexual dimorphism?

Location: West Bengal, India


texts: How is signalling disturbed in trophoblastic cancer cells?

texts: Trophoblastic cancer seems to be a form of growth that no longer responds to the neural signals which try to inhibit them. Can someone please explain whether experiments have been performed as to how exactly cancer cells manage to "shut off," these neural signals?


texts:
I have always imagined that cutting the umbilical cord after birth might be painful. But I have always been confused about who would feel the pain and why. It occurred to me that the mother or the infant could only feel pain if they had nerves connected to the umbilical cord.

Do either mother or infant have nerves running into the umbilical cord that carry nociceptive information?
If not, is there a reason why no pain receptors are present?


texts: Insulin and monoclonal antibody production

texts:
When producing insulin, the gene for its production is inserted into the plasmid of a bacterium that is allowed to replicate freely.

Why can't the same thing be done with antibodies (as I understand it, currently cancer cells are fused with mammalian cells that produce these antibodies, and now the tumour is allowed to replicate, much like the bacterium, making more antibodies)?

What is different about these two proteins that means fairly distinct processes of production are required for each?


texts: Do we instinctially interpret birdsongs as a sign that there are no predators present?

texts:
I was outside today thinking how nice it was to hear the birds back from winter when I started thinking about the fact that we like bird song.  It makes us happy in a very basic level, the sort of level that usually implies subtle evolved instincts.  Thus I started wondering, why do humans all over the world naturally love the sound of birds?

The simplest explanation that came to my mind was because birds supposedly will flee or be quite when predators are around.  Thus the presence of birds singing may indirectly mean a lower chance of predation.  In other words it's less that were happy when birds are singing, as that were a little more on edge when they aren't singing.

However, that seems almost too easy an explanation.  Has anyone more intelligent then a random computer geek who's just happy to be away from the computer for a few hours put any more effort into considering this?  What is the generally accepted hypothesis?


texts:
I need 16S rRNA and 5S rRNA (Gammaproteobacteria - E.coli) Secondary structure files in ct format.

I tried looking for them in different RNA databases, could not find one. Can someone tell me where to find such datasets?

Thanks in advance.


texts: Is this a black carpet beetle and how do I keep it alive?

texts: About 3mm in length, location Hong Kong. Is it possible to keep it as a pet? I currently have it in a clear plastic case (kinda cubic, 6.5cm per side) with a piece of moist paper. It rarely flies.


texts:
I have a question about the experiment that using microinjection to inject RNAi into the C. elegans. To prepare the dsRNA for injection, fist have to clone the gene of interest from the worm genome DNA and insert into a plasmid that has either T3 or T7 promotors. To clone the gene of interests, one has to design the primers. There is a paper descripting the protocol of the microinjection. Here is the link to the paper: http://labs.bio.unc.edu/goldstein/dudleygoldsteinmmb05.pdf
It is said that the primer for clone need to add sequence of T7 Promotor, but why? and why just add partial not complete sequence? why is it in the second step of PCR? Is it required to add the restriction enzyme site to both primers? Why?
Also in the feeding experiment, the plasmid(insert) is transformed into the HT115 strain and use IPTG to induce the expression of dsRNA. However, the microinjection is using dsRNA to inject the worm. So after cloning the gene of interest and insert into the plasmid, is the dsRNA expressed in the vitro before injection? And how? Thank you!


texts: I found this in my hair this morning! Yucko! Please help me identify it. I have tried and tried to no avail.Thanks in advance.


texts: Why I obtain larger bands than expected after minipreparation?

texts:
guys!
I made a "home made" minipreparation to obtain my plasmid+insert (totalizing approximately 6Kb). But, when I run a agarose gel, I saw a unique band with 10Kb. Why?


texts:
I know that it has alpha1, alpha2 and beta1 effects.
It has beta2 receptor where epinephrine can effect.
However, to say that it is beta adrenomimetic, I am not sure.
That is ligand binding beta2 receptor causes a stimulatory effect.

Is norepinephrine beta2 adrenomimetic?


texts: How do sporozoites travel into the human host when the mosquito is sucking blood?

texts: I mean how are the sporozoites able to swim in the reverse direction of blood flow through the proboscis of the mosquito into the human body?


texts: What is the evolutionary tradeoff against primates producing multiple offsprings (litter)?

texts:
If we evolved to have multiples all the time we would more likely have extended families living together in 1 house. This would be better than the spouses by themselves for multiple reasons including money.

And during prehistoric times it would have been better for several reasons including that 1 would be more likely to survive than if it was born without any siblings.

Most mammals have litters of at least 2. An extreme of this is the cheetah which has litters of up to 9 cubs. They evolved to have litters because they were in conditions where 1 is likely to starve. Lions evolved this for a different reason since lions are not likely to starve. They evolved it because of the fact that they live in prides.

So for primates including us wouldn't it be better if they had litters often instead of single babies?


texts: Is it possible to repopulate lactase in the stomach?

texts:
Possible Duplicate:
  Can an adult without genetic lactase persistence still develop a tolerance for dairy foods?

In my younger years, I don't seem to have a problem drinking milk.

Nowadays, when I drink milk, I keep farting away.

After searching around the Internet, this site claimed that it is due to lactose intolerance. They have a product that claims to be able to repopulate the enzymes in the body so that it can digest milk. Is this product based on sound principles?

Can someone (other than the Dairy Care company itself) refute or support its claims?

Thanks!


texts: What are the obstacles to a quick survey of statin usage in COVID-19 patients?

texts:
A recent preprint paints a grim picture of the effect of role of obesity in COVID-19 infection.  A high role of C-reactive protein (CRP) is specifically indicated as a risk for critical illness.

It is possible to reduce the level of CRP by statin administration, but statin administration raises the level of ACE2.  It is not known whether that increases or decreases the risk from the virus.  The use of statins for coronavirus patients has been suggested - so has the possibility of the discontinuation of statin use by infected patients.

Obviously I would hope to see a study of statin use in COVID-infected patients, and one does begin recruiting this month.  The entry, however, says that it will be completed in August 2021.  My thought is that surely somebody could run around the New York COVID wards with a clipboard, though I'd hope for a wiser way to do this, asking patients whether they use statins versus whether they have ever turned down the suggestion of taking statins when their doctor mooted the issue, and seeing how many of which group ended up in the ICU.  What are the factors preventing data like this, which could have such influence on the way people respond to the outbreak, from being collected and published within a couple of weeks?


texts:
Just saw this beetle on my window.
The coin is an American dime.
Location is Shenandoah Valley,
in central Virginia, U.S.A.


texts: How does RNA polymerase II CTD bind to the RNA modification proteins if the tail is flexible?

texts: The tail of RNA polymerase II is flexible, not folded into a fixed structure , but does each repeat have more "rigid" structure (i.e. fold into a structure that has less rotation freedom inside a repeat)? If not, then how can the proteins bind some repeat with high specificity? (you can't make lock and key with soft material)


texts: Regulation in plants bearing cleistogamous and chasmogamous flowers

texts:
In most plants bearing cleistogamous flowers, chasmogamous flowers are also borne by the plants. For example, Viola, Oxalis and Commelina contain both these kinds of flowers.( I am unaware of a species which bears only cleistogamous flowers, which would be very unfavourable for evolutionary success)

The Cleistogamous flowers help in reproduction with minimal energy and resource expenditure. It also maximises the chance of reproduction, which is an important factor where the agents of pollination are scarce. On the other hand Chasmogamous flowers provide variablity, hybrid vigour and generate better genotypes through recombination. Both of these strategies are useful in different environment. In adverse (less pollinators, energy stress) cleistogamy would be favourable, and in other cases where no energy stress prevails, chsmogamy is advantageous.

  My question is, How can plants, if they can, regulate which strategy
  is supported? Is the ratio of cleistogamous to chasmogamous flowers
  constant irrespective of the environment, or does the prevailing
  environment have a say in deciding which of these two kinds of flowers
  will be preferred over the other? If it does, what is the regulatory
  mechanism underlying this control of flowering startegies?

One other related question is whether there are any species which bear only cleistogamous flowers? That would seem very unfavourable for evolution to act on.


texts: How does eutrophication yield lower levels of dissolved oxygen?

texts: Where do the oxygen go? Is it consumed by a particular species? Is just not enough being made? Please explain.


texts: Ligaments at the posterior superior iliac spine

texts:
In Causes of Back Dimples, it was determined that these 'Dimples of Venus' are created by

  a short ligament stretching between the posterior superior iliac spine and the skin. They are thought to be genetic. (@Johnny)

The linked article in the answer to my original question says nothing more other than the fact that dimples of venus are normal dimples (not medically significant).

DrLumbago.com states:

  The sacroiliac joints move together as a single unit.  From the back it is common to see a pair of dimples on the buttock near the base of the spine.  These are sometimes called the “dimples of Venus” and they are a landmark for the top portion of the sacroiliac joints.

Posterior superior iliac spine (PSIS) marked in red

Image made by DBCLS (Polygondata is from BodyParts3D) CC BY-SA 2.1 jp, via Wikimedia Commons

Ligaments of the PSIS

Cooperstein & Hickey (2016) has an image of ligaments connected to the PSIS, but unless I am mistaken, the image doesn't seem to have the ligament(s) involved with the dimples of venus.

It seems from the description in Kumar, et al. (2014) that the "dimples of venus ligament(s)" are connected to the skin, and seeing that ligaments are fibrous connective tissues that normally connect bones to other bones, I am intrigued to know more.  What is the name of these "dimple of venus ligaments" and what is their purpose?

References

Cooperstein, R., & Hickey, M. (2016). The reliability of palpating the posterior superior iliac spine: a systematic review. The Journal of the Canadian Chiropractic Association, 60(1), 36.PMCID: PMC4807681

Kumar, A., Kanojia, R. K., & Saili, A. (2014). Skin dimples. International journal of dermatology, 53(7), 789-797. DOI: 10.1111/ijd.12376


texts:
Update: I have just received a grant to pursue this research.  However, I must still perform the preliminary experiment described below before dipping into my very limited funds.  Thank you for any ideas.

What are some accurate methods to measure the rate of photosynthesis that can be performed without access to a professional laboratory?

I am a citizen scientist who is designing a experiment to measure the rate of photosynthesis under different conditions.  Although this idea stems from my interests as an amateur horticulturist, it has grown to into something of real scientific potential.  However, I must conduct this experiment on a low budget without access to a professional laboratory.

Furthermore, I should note that it is almost impossible to quantify photosynthesis by measuring gas emissions in this scenario. The only way to keep the plants in a stable environment with equipment that I can afford is in an open, climate controlled room, (as opposed to a closed testing chamber that could trap gasses).

Any ideas on how to measure the rate of photosynthesis would be greatly appreciated.


texts: If I am not mistaken, during exposure to electricity sources it is the magnitude of the current and not the voltage that kills the human body.  If so, what is the order of magnitude of current that human body can sustain, and for what duration?  How do defibrillators exploit this?


texts: Is there such thing as "half-life" of dopamine?

texts:
If a dopamine is released at T=0 and binds to receptor D2, what determines the time when the concentration of this neurotransmitter bound to the receptor reaches half of the original concentration? In other words, when will the effect of neurotransmitter on the intercell signalling fall in half?

Is there any time estimate of how quickly the brain thinks that neurotransmitter has "fulfilled its purpose" and is to be re-uptaken? Or is this process completely random?

Thank you for your input!


texts: Why is the Pentose Phosphate Pathway so active in erythrocytes?

texts: Is it because glyceraldehyde -3-phosphate (a molecule which when enter glycolysis help produce ATP through substrate level phosphorylation) can be prepared without losing an ATP through this process?


texts:
I have searched around and read my textbook but I am failing to understand how enantiostasis is different to homeostasis. For reference, Wikipedia definition is as follows:

  Enantiostasis is the ability of an open system, especially a living organism, to maintain and conserve its metabolic and physiological functions in response to variations in an unstable environment. Estuarine organisms typically undergo enantiostasis in order to survive with constantly changing salt concentrations.


texts: What kind of animals are these little creatures?

texts:
I have 3 tanks. 1 with my fishes and 2 other are technical.
The smallest one is 0.5l and I'm using it as trash bin where I put dead plants and algae from main aquarium and it has sand from the see at the bottom. For more than 5 monthes it was full of algae and no alive creatures. Now it has many live black dots that are very fast moving and now the tank is very clean.
Second technical was planned to used for daphnia (didn't get it yet). It has 5l volume now. In the bottom it has simple ground and rasied Glossotigma eletinoides from the seeds. Also it has many algae (including Spirogyra).
Two tanks are closed tightly.
I have a some questions about it:

What kind of animals are these?
Can I move black dots to the other tank to have it clean from algae?
Are these creatures safe for me?
Are these creatures safe for my fishes?

I recorded video, it has 3 parts (1 tank, 1 tank in zoom, 2 tank in zoom):
https://youtu.be/3jbqPiAcKOc

Update:

Tank 1. This animal is hard to catch

Tank 2. In water I see only one type and on the stick I got 2 different animals. The left one looks like one of the species of daphnia.

Update 2:
I think I found what I have in the tank 1. It is some sort of Ostracod (seed shrimp), because I saw whiskers and slit in the shell


texts: How to solve the problem of 2 melt peaks in real time PCR?

texts:
I am facing a problem in my real time experiment. After standardizing the annealing temperature by semi-quantitative PCR, I did real time for my gene of interest. In one of my samples, I got 2 peaks in the melt curve. Thinking it would be non-specificity, I tried by increasing the temperature further by 3 degrees. But still found 2 peaks in the same sample. I ran the product in a gel and found one blazing band and below it another distinct band. Is it still non-specificity or I am starting to think it could be an isoform? Also, in the same sample, with respect to control, protein expression is increasing whereas when I analyzed my real time, the RNA levels are coming low. Please provide your inputs.

See an image of the melting curve below. The red ones are melt peaks of my gene of interest. Green is of housekeeping gene. There are only 2 samples that show two peaks.


texts: Why is the floral biodiversity of grazed grassland higher than that of mown grassland?

texts:
I have collected some data to compare the biodiversity of a field in which the plagioclimax is maintained by machine mowing with a field in which the plagioclimax is maintained by sheep grazing.

What I found was that there was a significant increase in floral biodiversity in the field which was managed by agricultural grazing when compared to the floral biodiversity of the machine-mown field.

I am trying to explain my findings, and I believe that it is due to the comparitively short amount of time that machine-mowing has been a grassland management technique, so there has been little time for natural selection to take place and for species to develop adaptations to machine-mowing (such as being low-lying, or extremely fast-growing). Whereas the field which is managed through sheep-grazing, contains multiple competing species which have adapted over time to grazing sheep, such as Cirsium arvense.

Moreover, the field which is managed by grazing has nutrients returned to it through defecation of the grazing animals, allowing for more favourable conditions for growth.

Is my explanation valid? Are there any other reasons why the floral biodiversity of a field managed by sheep grazing would be higher than one managed by machine-mowing?

Thanks in advance!


texts: What is it called when a dead flower is rotted away and only the veins remain?

texts:
I've spotted a flower that is dead:

It looks like most of the tissue has rotted away and only the veins remain.

(Sorry, I don't know the proper name for flower veins).

What is the technical term for this phenomenon?


texts: Extremely Scientific Sexual Education Material?

texts:
I'm trying to prepare material for 'the talk' about sex and reproduction. I know there's plenty of great books and resources out there for young readers, which I'll use to start with, but I'm also looking for something overbearingly scientific.

Essentially, I'm looking for an academic-level resource that is as close as possible to a literal play-by-play second-by-second explanation of puberty and the entire reproductive cycle. This is partly to polish my understanding, and to prepare myself for unexpected questions.

For example, it should explain the mechanics that sperm/egg cell(s) use to get around, how sperm penetrates the ovum, the process of breast development, and how they become lactation-ready, how the milk is made, what controls where adult body hair grows, the chemical process leading to feelings of lust, etc.

I was mentally reviewing my knowledge of this the other day and realized I know a lot of 'what' but not 'how' or 'why', so here I am.

Multiple books/resources is fine.


texts:
With respect to this website:
http://horfdb.dfci.harvard.edu/
what does the term clonal isolates mean?


texts: What happens during kefir fermentation process?

texts:
I’ve found many sources about the positive effects of kefir for the digestive system. However I haven’t found any information about the fermenting process.

What is the exact biology (chemistry?) behind the process of milk becoming kefir?

What do the kefir grains exactly consume from the milk? And what do they defecate?  What happens inside the microbes?


texts: What is the advantage of the inverted image on the retina?

texts:
Recently, I learned that the image of the world which we see actually reaches the retina inverted.
This is due to the fact that the retina lies behind the focus of our eyes.

I have two questions:

When the retina lies behind the focus and the lens in our eyes has a spherical shape, shouldn't left and right also be interchanged?
What is the advantage of this? Why does the retina lie behind the focus and not in front of it?
Or doesn’t it matter since our brain is not a real screen and it’s only a question of the correct interpretation of the electic signals?


texts: Why is 70% ethanol preferred for aseptic techniques?

texts: Are other concentrations (say 80%) less effective,or is this just for convenient manufacturing? Is the concentration chosen only because it is less volatile than 100 percent ethanol and hence safer?


texts: We know archea and eukarya are more closely related but endosymbiotic theory says eukarya have evolved from prokaryotes, justify the statements?

texts: I am confused if eukaryotes have evolved from prokaryotes then how are they more closely related to archea?


texts: Is it possible to suffer from hyperthermia by spending too much of time in the hot springs?

texts: People may tend to spend time in a hot water spring. Is it possible to get hyperthermia (like a sun stroke) due to this?


texts:
I live in the southern rocky mountains of Canada. I was in bed the other night when I saw a small scurrying shadow out of the corner of my eye. The source of the shadow was a small spider (95% sure it was a barn funnel weaver), approx 2cm in diameter. I killed the spider.

Interestingly, what intrigues me is that the place on my bed where I killed the spider the jus of the spider had melted to the sheet (!). How could that happen?


texts: Co-transformation of plasmids from the same incompatibility group

texts: Can two plasmids with the same origin of replication (for example pBR322 ori) and thus from the same incompatibility group be successfully co-transformed in E. coli? What are the mechanisms that would prevent the two plasmids from co-existing together? Does it matter what is the dual resistance selection? How would the efficiency of co-transformation compare to the efficiency of a uni-transformation?


texts: I took a picture of this bug when I was camping with my boyfriend in Ontario, Canada. The little guy (or gal) kept wanting to climb onto my hand which kind of freaked me out. I'd love to know what kind of bug this is!


texts: Why is the central tendon of diaphragm called a tendon?

texts: Why is the central tendon of diaphragm called a tendon when it does not connect the diaphragm to any bone?


texts: Depositing/publishing protein structure simulations

texts:
Just wondering if anyone has any information on what the general consensus on publishing/depositing online protein structure simulations is?

I've been doing a fair bit of work to characterise the 'quality' of the simulations I have (how well they approximate known homologous structures), but don't know what is generally thought of protein structure simulation methods. They do a lot of work in the CASP programs every couple of years to assess whether they simulate accurately, so a plausible structure simulation should be a valid surrogate for an otherwise unknown protein IMO?

Are the online databases purely for structures resolved experimentally?


texts: What is the cause of "imbalanced" linkage disequilibrium?

texts:
With perfect linkage disequilibrium ($D' = 1, R^2 = 1$), you might have the following table of counts for the alleles:

    B     b
A  100    0
a    0  100

With "partial" linkage disequilibrium ($D' < 1, R^2 < 1$), you'll see something like this:

    B     b
A  100   25
a   25  100

But I've sometimes seen the following "imbalanced" linkage disequilibrium ($D' = 1, R^2 < 1$):

    B     b
A  100    0
a   50  100

What gives rise to this sort of situation, where aB occurs, but Ab never does? Is there a name for this phenomenon? Which is a better measure of linkage disequilibrium in this case, the normalized LD coefficient $D'$, or the squared-correlation $R^2$?


texts: What is this yellow sticky excretion from a moth? Details in photos

texts:
Saw this moth on some grass the other day and took some bad phone photos. I'd like to know what the yellow excretion is. I believe it is an excretion from the moth (as opposed to for example, some bubble gum someone dropped on the ground), because it was attached to the tail end of the moth instead of its whole body.

I tried to label the pictures as best I could, you may have to look closely. You can only see a tiny portion of the moth wing in the first picture, below.

The yellow thing was quite sticky but not as hard as bubble gum, as it stopped the moth from flying away. It was frantically flapping its wings trying to get away from some ants, which seemed to be very attracted to the yellow thing. At first I thought the swarm of ants were eating the dead moth, but the moth was alive and the ants were more interested in the yellow sticky thing. I got a thin stick and pulled away some of the sticky stuff and the moth was free enough to crawl away, taking the yellow sticky thing with it, leaving a thin trail behind, like when you stretch out bubble gum. It seemed to be very sticky to the moth and my stick, and very tensile, because unlike a spider's web, I was able to draw it out more when I tried to pull it away from the moth to free it.

I am so curious to know what it might be. I don't think it was made by ants, because it seemed to be attached to, or coming from the actual moth, although, the ants did not seem to be stuck to it.

Please add "moths" to the tags if you have enough 'reputation level' to do so.
Thank you


texts:
When visiting the south of France (around St Tropez) I had a plant in the garden which I initially mistook for mint but the aroma of the leaves (when rubbed) was distinctly different (I cannot put a name on it, it is sweet and remotely reminds of orange).

The plant has bare branches (it is a bush), and beside the leaves there are some round things which I took a picture of (sorry for my abysmal lacks in correct botanical words - these are the last two photos).

The photos are as of end of October.

The leaves are not smooth, they have some kind of tiny barbs which I can feel when rubbing the leave upwards (towards the petiole). The other way round (from the petiole) is smooth.

I cannot tell about the taste yet as my wife suggested that I wait for more information (just kidding).


texts:
Can - on a very coarse level - the functional role of dendritic processing as a whole (at least one of possibly many functional roles it might play) be described as rewarding spatially coherent synaptic inputs when creating action potentials?

This would make sense, when the mapping of neurons to synapses was neighbourhood preserving (in the sense of topology): the efferent synapses of two neurons in close vicinity (in other parts of the brain) sit in close vicinity on the dendritic trees of their common target neurons.

Then it would be desirable, that when a group of $n$ neurons in close vicinity to each other (e.g. a nucleus) projects to a subtree of the dendritic tree (i.e. synapses in close vicinity) and those neurons are firing at the same time, this should evoke an action potential in the target neuron, but not, if $n$ synapses spread randomly over the dendritic tree are active at the same time. To achieve this could be the (or one) function of dendritic processing.

As I said: this is a very coarse level of description, and to be taken with some grains of salt.

(The whole question would break down if there is no such neighbourhood preserving mapping from neurons to synapses.)

References

I've read the following articles (but maybe not carefully enough to be able to pin them down to the short form above):

Buonomoano/Maass, State-dependent computations: spatiotemporal processing in cortical networks
Stuart/Spruston, Dendritic integration: 60 years of progress
Poirazi et al, Pyramidal Neuron as Two-Layer Neural Network (this article comes closest to the spirit of my question)
Magee, Dendritic integration of excitatory synaptic input


texts: My Queen ant has laid eggs but has not dropped her wings, is this ok?

texts: My Queen ant has laid eggs but has not dropped her wings! I caught this Queen in England, I've had her for three days and she's laid eggs already but I was expecting her to to drop her wings first as she needs the wing muscles to feed her brood. I don't yet know the species of the queen but I'm suspecting it's a camponotus queen but I'm not sure, the queen is 1cm long and 4mm wide, the gastor is bigger than the thorax and she is black. (I haven't got a recent photo of the queen because I am currently away on holiday and will be for the next month. (My mum is still at home though so that's how I know there are eggs and the queen still has her wings)).Is there a species of ant that never drop there wings or don't drop them for a long time?


texts: Can 'human' become a genus due to space colonization?

texts:
I have read that during the Second World War, some mosquitoes got trapped in the London underground railway system. The mosquitoes never got out and eventually they became a new species by themselves.
I had a similar thought. In the next few centuries, if humans could, in theory, colonize other planets like Mars, Proxima Centauri and beyond, then the environments there are not the same as Earth. So, in the long term, humans who would be born and who would grow up on Mars, for example may become more and more suited to Martian conditions than Earths.
Now, when early humans explored and ventured into new geographical areas, they did change characteristics, but we are still one species Sapiens. But living extraterrestrial, is a whole new thing. The gravity alters, the entire atmospheric composition does. So that is going to have some significant changes on humans.
So, my question is: is it possible that in millions or even billions of years, if humans expand to space, there may arise separate species of humans? And would this new emergence of human species actually result in humans moving one step up the taxonomical ladder: becoming a genus?
EDIT: To avoid confusion and create speculations at the answers, I should specify that I am talking about a very particular case: if Sapiens are living in different planets, then is there a chance that Sapiens will become a new genus, and that Homo can be taken one step higher in the taxonomical order? There would still be Sapiens on Earth, but considering the environmental changes that could happen here too, humans then can be drastically different from humans now. So the question is: can 'Sapiens' become a genus?
Thanks to @tyersome and @jamesqf for pointing this out.


texts: Can primary tumor cells grow in 2D culture?

texts:
Is it possible to expand primary tumor cells in 2D culture? Are they adherent cells? Do you have any experience especially with culturing non-small cell lung cancer in 2D?
Thank you.


texts: Difference between genetic engineering and synthetic biology

texts:
I've recently seen the term synthetic biology being used to describe research involving genetic modification of organisms. What is the difference between synthetic biology and genetic engineering?

Is it just a new term for the same thing, or is it something different? Does one of the two terms encompass the other?


texts: Are there biological reasons why life expectancy is lower for men in most countries of the world?

texts:
I've been checking life expectancy figures for men versus women in many countries of the world and the figures for men sometimes are terrifying. Countries like Russia have a 12 years gap in disfavor of men. Developed countries have usually a 4-5 years gap in disfavor of men. My country Argentina has a 7 years gap. African countries and middle east countries where supposedly women have a harder life because of religion have usually a 3 years gap in disfavor of men. So far I haven't found a single country where men lives more than women.

Now I know there are more men than women who dies in homicides, suicides, work accidents, wars, etc. men are more likely to get addictions because of depression, etc. but aside of all that, is there any biological reason why men lives less than women everywhere?


texts: How pricey does the media need to be for a typical bacterial culture experiment?

texts:
I'm considering various lab supplies for a protocol we're going to be running, and have been struck by the remarkable difference in price for different quality levels of the same basic substance.
Sigma will sell you water, for example, for anything from \$15/L to \$500/L and even over \$10,000/L, depending on what level of purity is guaranteed. Obviously, one doesn't want to use inferior tools and guaranteed unreliable results, but also it would be foolish to use a reagent that's far pricer than one's actual tolerances.
Most of the actual protocols that I encounter, however, don't seem to actually specify what grade of purity they need, and I'm trying to figure out how to navigate the problem. Trial and error is definitely not a good option, since (a) it can waste a lot of time, and (b) good and bad results in a trial don't actually tell you what you need (a good result could be an unusually good batch of poor reagent; a bad result could be from an entirely different problem). Asking the authors is also not a great solution, for a number of similar reasons.
To make this concrete, let's consider a very simple and typical case that I am currently encountering. The protocol I'm setting up for right now cultures E. coli in LB media. Sigma will sell me LB media powder as "quality 100" L3152 for \$139/kg and "quality 200" L3522 for \$182/kg. Both say they are "good for E. coli".
Is there any reason not to pick the cheaper media? How should one decide how much quality their media needs to have for a typical bacterial culture experiment?


texts: What decides whether an activated B cell will get converted to plasma cell or memory B cell? Is it necessary that out of a mitotic division one will convert to memory B cell and the other to plasma cell?


texts: Is there a metric for “evolutionary agility”?

texts: By "evolutionary agility" I mean how fast an organism can adapt to changes in the environment. I’d imagine that a population with more offspring and a shorter time between generations would be more “evolutionary agile”.


texts: Lack of skin in a certain area of the body --- hypo[what]?

texts:
Lack of skin in a certain area of the body. How shell I name this?

Hypocutaneousis?
Hypo[somethingElse]?

What is the correct term?


texts:
I have recently encountered this red thing on one of the beaches of east Sardinia. It was pretty close to the coast (around 20 meters) and has sticked to one of my fins.

My question is: how is this creature called? Is it dangerous to have skin contact with it?


texts: Is it possible to fuse DNA from two sperms into one sperm?

texts: Is it possible to fuse the DNA of two genetically different sperms into one singular sperm? In theory, half of the number of chromosomes in a normal sperm would come from one sperm and the other half could come from a separate sperm. In return, the fused sperm could fuse with a healthy egg cell for fertilization.


texts: Can potassium ions depolarise neuron membranes?

texts:
I am reading a journal paper about the cell adhesion molecule NCAM2 and I have come across the following statement:

To confirm the functionality of the reporters, neurons were time-lapse
recorded before and after application of 90mM K+ used to depolarize
membranes and induce Ca2+ influx via VDCCs.

I know that depolarisation is when the membrane potential of a neuron becomes more positive. I have read that the opening of channels that let positive ions flow into the cell causes depolarisation, such as the opening of channels that let Na+ into the cell.
However, the above statement in the paper seems to imply that extracellular K+ ions can also cause membrane depolarisation. I am not sure what the relationship between potassium ions and membrane depolarisation is and I have not found anything about it online. Any insights are appreciated.


texts:
The Young's modulus of elasticity when a bone is stretched is : 16×109 and when it is compressed, it is 9×109 N/m2. That means, change in length will be more if you compress a bone as compared to stretching it.

What is the biomechanical reason behind this ?


texts: How many cells should be seeded for passaging?

texts:
Do you count cells when you passage them?
I found that many people will according to a ratio (maybe 1：2 or 1：3，etc.) to subpackage. It is so indistinct!
What is the optimal seedling density or optimal original confluent in various sizes of cell culture dishes and flasks?
that's all, thank you!


texts: Why do slime molds pulsate when growing into their fruiting body?

texts:
An example can be seen in this Youtube video, where the slime mold pulsates as it engulfs a rock in order to form its fruiting body.

Why does this pulsing happen?