15
votes
3answers
930 views

Do probiotics survive digestion?

Pretty much this. I've been wondering if any of the yogourt and other "health" foods containing living probiotic cultures survive digestion to populate our intestines? If so, is there peer-reviewed ...
5
votes
2answers
179 views

First pass protein structure prediction

I'm working with a protein that doesn't have any homology to other proteins so it will likely require ab initio structure prediction. However, since I don't work for a structure prediction lab and I ...
5
votes
1answer
135 views

Descendants of dinosaurs

It is commonly accepted that birds are descendants of dinosaurs. It is nice that not all dinosaurs died out. Are there other animals, descendants of dinosaurs, that survived ? (Maybe not till our ...
6
votes
3answers
284 views

Compressing structural information in PDB files

There seems to be a lot of redundancy in PDB files. These files can of course be compressed with general-purpose compression programs like gzip, but I can't help but imagine that these tools are ...
6
votes
1answer
99 views

Mechanics of going from DNA sequence to metabolic network

My apologies for possibly a naive question. I'm a statistics type and have been asked to assist with analysis of metabolic pathways (and networks). However, I would like to have at least a layman's ...
21
votes
3answers
3k views

What actually happens when my leg 'falls asleep'?

Most people have experienced the temporary loss of feeling and tingling in their leg resulting from sitting in an abnormal position for a short while. Usually you get a loss of feeling in your leg ...
5
votes
1answer
110 views

How do I prepare a PDB for submission to the Protein Data Bank?

I have a couple structures that are nearly ready to be deposited in the PDB. Out of curiosity, I ran them through the ADIT's precheck tool and they failed with one error after another, as I lacked ...
7
votes
2answers
1k views

Altering the human genome

I recently had a conversation with a rather unusual gentleman who was, let's say, more than a little partial to conspiracy theories. He has this idea that governments are lowering "nanowires" from ...
19
votes
2answers
660 views

Why is rabies incurable?

I'm still not sure about the mechanics that lead to rabies being incurable. I know that it can be treated before any symptoms show up, but why is it that once symptoms show the person is a dead man ...
11
votes
4answers
262 views

What was the reason for some plant and animals to become giant in course of evolution?

The dinosaurs, mammoths, giant plants etc are known to be bigger than modern animals. I wonder why they had been lived and why they are not living now? I really don't know much but is it something ...
3
votes
2answers
355 views

Why do plants' leaves become enlarged in low light areas?

Why do almost all plants in shade have a smaller stem structure and larger leaf than that same species grown in a well lit, sunny area?
5
votes
1answer
68 views

How are the various classes of E coli genes determined?

Looking at some more detailed codon usage tables, genes may be further clustered into three gene classes: Metabolic genes, highly expressed genes during exponential growth, and horizontal gene ...
10
votes
1answer
139 views

Were dinosaurs 'hot-blooded' or 'cold-blooded'?

Were dinosaurs hot-blooded or cold-blooded? NOTE: The popular term 'hot-blooded' means having an internally maintained average body temperature, which is generally more than that of the surroundings, ...
13
votes
5answers
343 views

Can species back-evolve?

One of the tenets of Darwin's theory is the survival of the fittest, ie adaptation of features that allow a species to adapt better to its surrounding environment. I am wondering that given the right ...
16
votes
3answers
301 views

How is the blood volume of a living organism measured without killing it?

How is the blood-volume of an organism measured without killing it? NOTE: The blood-volume of an organism is defined as the total volume of blood present inside that organism.
21
votes
1answer
315 views

Phagemid display

If I'm using a bacteriophage for phage display and I'm trying to avoid avidity effects by using a helper phage what would be the best way to maintain a large library size while keeping everything ...
7
votes
1answer
173 views

What is the fastest way to build an alanine scanning library?

For interfacial studies, I would like to build an alanine scanning library for one of my proteins examining 20 sites. I will ultimately express the gene using E.coli cell-free protein synthesis. I ...
7
votes
1answer
196 views

What is the difference between copy number changes with and without allelic imbalance?

I require some clarification on copy number aberrations (structural gain and loss in chromosomes). From what I understand, gain/loss per se can be divided into two types. Consider two alleles, A and ...
5
votes
4answers
4k views

RNA or ribosome, which one moves during translation?

During translation ribosomes decode the genetic information present in the mRNA and protein synthesis takes place. During this process which of those two does move, the ribosome or the mRNA?
9
votes
1answer
772 views

How does population stability evolve?

The number of individuals constituting a population is called population size. Over time population size does not remain constant, it fluctuates to different extent over generations because of ...
13
votes
1answer
197 views

How straightforward is in vitro compartmentalization?

in vitro compartmentalization (IVC) is one of those technologies that everyone knows about, talks about, but never actual does due to the rather technical difficulties in setting the system up. I was ...
11
votes
2answers
174 views

protocol for pulldown of DNA breakpoints?

Is there any method to do pulldown enrichment of DNA breakpoints from a cell? I have found this paper reporting a method to enrich for the DNA single-strand breakpoints from meiotic recombination ...
3
votes
2answers
894 views

Neutralizing TCA washes

Trichloroacetic Acid (TCA) is commonly used for protein precipitation but the wash waste needs to be neutralized prior to disposal. What exactly is required to effectively neutralize TCA waste? Do I ...
5
votes
2answers
365 views

What does the 34/70 in Saccharomyces pastorianus Weihenstephan 34/70 stand for?

I've searched everywhere. No Wikipedia page. No information on NCBI. I searched all occurrences of 34/70 in some primary research articles! The best I've found is this brewery forum where someone ...
25
votes
3answers
10k views

Why do eukaryotic organisms have introns in their DNA?

We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not ...
5
votes
1answer
291 views

How long does it take to stain cells?

I'm never going to run these type of experiments but I do need to have a good idea of their timescale. After I fix my cells, if I stained my cells with histology stains like DAPI, Fluorescein, and ...
5
votes
0answers
126 views

What temperature should mammalian B-Cells be stored at outside of the incubator?

I'm working with murine B-cells. The general protocol is to keep cells on ice to keep them from dying but I've noticed that it makes these cells aggregate and precipitate out. I've heard suggestions ...
8
votes
2answers
7k views

Glomerular Filtration Rate

In practice, when you have vasoconstriction of the glomerular capillaries and subsequently an increase in blood pressure, glomerular filtration rate increases. However, this seems counterintuitive to ...
7
votes
1answer
197 views

When collecting cell lysates for a Western blot, how do I induce di-sulfide bonds?

I would like to conduct a simple dimerization experiment for some protein I'm collecting from a cultured cells. My thought is, that if I'm running a non-reducing, denaturing PAGE gel, then removing ...
7
votes
1answer
3k views

How do Proteins migrate in MES vs. MOPS

My gels look significantly different in MES (2-(N-morpholino)ethanesulfonic acid) and MOPS (3-(N-morpholino)propanesulfonic acid). That is to be expected. What I don't understand is why the simple ...
5
votes
1answer
4k views

How do SDS-PAGE gels differ in a Bis-Tris system vs. a Tris-Glycine system?

Protein migrate differently in Bis-Tris and Tris-Glycine gels. I was curious about the actual reasons why. Do certain gel systems result in a tighter resolution than others?
5
votes
2answers
152 views

Analysing the results of real-time PCR

I want to evaluate the level of gene expression by real-time PCR. I have five controls that are "clinically" the same. I calculated the "fold change" of the target gene regarding each control. What ...
7
votes
1answer
100 views

Soma-soma paired neurons

I'm reading this paper for a presentation I have to do. Since I have no real biology background I encountered a few questions and one I couldn't find an answer using my google-fu. It's about how ...
9
votes
1answer
122 views

Organ cloning - possible to make a non-antigenic organ?

From a J. Neil Schulman article on Organ Cloning: Cannibalizing organs from other people also entails the risk of rejection because of incompatibilities, not only for tissue-typing but also ...
5
votes
1answer
167 views

What evolutionary mechanism caused felines to develop purring?

And why can some felines roar while others meow?
8
votes
1answer
201 views

Why are some bodily fluids more of an infection risk than others?

Whilst on a recent refresher course it was highlighted that when considering risk of exposure to infection from bodily fluids we should be aware of two distinct risk levels: High Risk: Blood Semen ...
6
votes
2answers
663 views

Are cells really the basic unit of all life? [closed]

Please see comments as to the appropriateness of this question on biology SE. All known life on Earth is made up of cells. It is thus safe to say that all known life is characterized by the presence ...
2
votes
1answer
185 views

Why do the sick and unhealthy trees leaf out first in spring?

It's spring. The time of year that trees start to leaf out. I have been watching them, and noticed an interesting pattern. The unhealthy trees of a species leafs out first. I've noticed this ...
11
votes
1answer
4k views

Fish “coming back to life” after being frozen

I've encountered a clip on Youtube showing a goldfish thrown in liquid nitrogen and immediately after to normal water and swimming normally. In the explanation to the clip it says: For everyone ...
9
votes
1answer
1k views

Will the “frog in boiling water not jumping out” work on warm blooded animals

There is the famous saying about a frog that is put in water that are slowly boiling will not jump out until it's too late. I realize it happens because of the frog's cold blood that adjusts to the ...
8
votes
1answer
196 views

Why is maintaining a circadian rhythm important?

What are the real consequences of never maintaining a circadian rhythm? How is circadian rhythm important for health and function? Where did it arise in evolution?
17
votes
1answer
20k views

Why is coffee a laxative?

How does caffeine (or any additional agents) act as a laxative when ingested? I'm interested in the metabolic/signaling pathway.
9
votes
2answers
283 views

Are there differences in DNA between humans of today and humans from 2000 years ago?

Are there any significant differences in our genome compared to the genes of our ancestors from 1000-2000 years ago? And if there are significant differences, do they result in significant ...
9
votes
1answer
133 views

Is there a biophysical causation from local field potential (LFP) to spikes?

Many experiments showed that neurons tend to fire at some phase (usually trough) of local field potential (LFP) oscillations, such as theta or gamma rhythm. LFP is supposedly generated by a population ...
9
votes
3answers
197 views

Does GFAJ-1 use Adenosine triarsenate as its energy currency?

Regarding the bacteria found in Mono Lake, CA that scientists believe uses or can use arsenic in its DNA backbone where life as we know it uses phosphorus (according to their experiments depriving the ...
12
votes
3answers
190 views

Why do some fruits have a much wider range of acceptable sizes than others?

Some fruits such as pumpkins can grow to be 100 lbs. Under different conditions, the same variety of pumpkin can produce a 15 lb. fruit. Both plants are healthy, and look the same except for their ...
12
votes
1answer
215 views

Why do people dying of immune deficiency diseases appear sick?

Please forgive the obviously silly appearance of this question, and/or of the tenor which may come across as flippant or dismissive of real world suffering. My intention is none of the above. As a ...
4
votes
1answer
94 views

Are CN3, CN7, CN9 and CN10 the only Parasymphatetic Cranial Nerves?

It has been my thought for a long time that that is the case but I am unsure about it now, since the parasympathetic tract of colon sigmoideum does not seem to have connection with CN 10. It connects ...
8
votes
2answers
172 views

Electricity generated by the body and its applications?

I recently came across this article from Nature. In it, it states that the snails have "tiny biofuel cells that extract electrical power from the glucose and oxygen in the snail’s blood", and that the ...
1
vote
1answer
87 views

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

I have the following tractus now: nucleus parasymphaticus sacrales -> nervus splanchnic -> ganglion terminalis -> colon sigmoideum The tract is parasympathetic. It suggests me that it should ...

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