13
votes
1answer
215 views

How does herpes (HSV) infection suppress HIV?

HIV compromises the human body to defend against infection. Yet people who are infected with herpes are at less risk of developing AIDS. How does this work?
8
votes
2answers
391 views

Why is blood pressure higher the more distal an artery is?

Why is blood pressure generally higher in more distal arteries?
8
votes
3answers
633 views

Why is methylcellulose used in pharmaceuticals?

Why is methyl cellulose used as a pharmaceutical excipient? Is it due to certain chemical properties? What are the reasons for relying on the chemical properties of methyl cellulose?
11
votes
2answers
332 views

Why do pandas have a high probability of giving birth to twins?

According to the BBC documentary "Wild About Pandas", about half of panda birth result in twins. Why do they have such a high probability compared to other mammals? What factor(s) control that ...
12
votes
2answers
142 views

How to decide which is the correct scientific name for a particular species

To start with, I am not a person having sound knowledge in biology. When I started my search for phyto-chemicals in a particular family in the plant kingdom, I got confused. The scientific papers use ...
15
votes
2answers
236 views

Can methylation from DNA get copied to RNA during transcription?

Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or ...
7
votes
1answer
76 views

Is there a standard format for plant community composition data?

FIA has a nice database of forest Inventory data, this would be great except that it does not seem capable of handling data from non-tree species (e.g., grasslands, wetlands). Is there a standard ...
11
votes
1answer
284 views

What is the mechanism that directs myosin walking?

Myosin, dynein and kinase all "walk" towards specific ends of the microtubule or actin filament they are on. I'm most familiar with the walking mechanism for myosin, where ATP fuels conformal changes ...
4
votes
1answer
213 views

Automatic cropping of collimated digital X-ray images

Do you have any suggestions for a library which offers an algorithm to crop digital X-ray images automatically? We receive full-size images (43x43cm) from a detector, independent of the collimator ...
8
votes
2answers
203 views

Why do animal teeth get darker if exposed?

I was wondering why the teeth of cats (And dogs, as far as I know, plus possibly some other animals or even humans) get darker if they are exposed to air / light? Example: (See the lower end of ...
4
votes
0answers
42 views

Serological assays not detecting native proteins

Is there anyone out there who has done much work with serological assays? We have antiserum for a manufactured viral protein but no luck so far getting it to detect native protein (unless today's ...
8
votes
1answer
193 views

What is the maximum potential sucrose concentration of plant sap? What keeps plants below this potential?

I am interested in identifying the maximum potential dissolved sucrose (%w/w) that plant sap could have, and which (biological, physical, chemical) factors constrain the observed sucrose ...
12
votes
2answers
2k views

How do insects breathe?

Do ants even breathe? If they don't, how do they stay alive? On what resources do they depend upon to stay alive? How are they different form mammals?
7
votes
1answer
210 views

Compare and contrast “Rubisco activity” and “assimilation rate” (is there a difference, and if so, what is it)?

I am confused about the variable "RuBisCO activity". How is it measured, and is it any different from the net assimilation rate? Based on some background reading (e.g. Kling, 2008; Lambers et al ...
17
votes
2answers
14k views

What is the difference between HPLC and FPLC and why is FPLC preferable for protein purification?

I've used HPLC (high performance liquid chromatography) before (once, so I'm barely even qualified to know what it stands for) so I was surprised when my labmate told me she would be using an ...
8
votes
2answers
149 views

What type of CCD system is required to take photos of luciferase

I'm working with luciferase and I want to be able to take a photo of it. The trouble is, I can see the luciferase glowing in all of its glory in front of me but no matter how hard I try, I can't take ...
9
votes
1answer
187 views

What are the effects of caffeine on the mammalian circulatory system?

A friend of mine told me an anecdote about his mother, who drank too much caffeine, to the point she became hypotensive and would pass out. Because caffeine acts as a stimulant, I'm assuming the ...
9
votes
2answers
384 views

Does arterial blood always flow away from the heart?

Is there a negative net flow of blood in human arteries at any point of the cardiac cycle? I realise that blood flow can be turbulent, e.g. in the aorta or around stenotic arteries, but then the ...
8
votes
1answer
231 views

How fast is the blood flow in various vessels?

How fast is the blood flow in different blood vessels, such as the aorta and capillaries?
12
votes
2answers
4k views

Do white Australians have a distinct look?

Background I've heard from many people working in tourism or similar industries that, white Australians can be recognized as Australian solely by their facial features. Being Australian myself I've ...
12
votes
3answers
228 views

When are population dynamics models useful?

When are population dynamics models useful? There seems to have been a lot of research about it, but how does it help? If I need data about how a population will evolve under what conditions, I need ...
5
votes
1answer
80 views

Why would we overexpress Sir2 by overexpressing its hypomorph (dSir2-EP2300) in C. elegans?

Can't we just overexpress regular Sir2 in the paper? Rather than overexpress a reduced-function gene? The paper is Burnett C, Valentini S, Cabreiro F, Goss M, Somogyvári M, Piper MD, Hoddinott M, ...
8
votes
1answer
110 views

Why is propanoic acid often added to the diet of C. elegans?

And what are its effects on C. elegans? The paper is Burnett C, Valentini S, Cabreiro F, Goss M, Somogyvári M, Piper MD, Hoddinott M, Sutphin GL, Leko V, McElwee JJ, et al.. 2011. Absence of effects ...
4
votes
1answer
479 views

Auxotrophic complementation test with yeast

If auxotrophic strains grow on minimal media do they complement each other or not? Also, is complementation the same thing as complementing each other?
8
votes
1answer
1k views

What influences the timing of human bowel movements in the morning?

I'm trying to understand if the timing of human bowel movements in the morning is associated with the circadian rhythm, and can thus be used to make predictions about the circadian rhythm. What ...
4
votes
1answer
289 views

Human sleep cycles and dream times, what influences the timing and intensity? Sleep history included

I'm doing sleep and dreams research and have developed an iPhone application to help me track my bedtime, rise time, sleep onset and also mark dreams. The app also monitors overall activity overnight ...
9
votes
3answers
1k views

Why some genes are dominant to each other? What is the mechanism behind it?

If i have a brown eye gene which encodes the protein that is responsible for the brown color, and have a blue eye gene either, what is the reason that my eye color is brown? How does one gene ...
8
votes
1answer
480 views

How are antibiotic resistant bacterial infections treated?

For example, how are infections of antibiotic resistant strains of MRSA, Streptococcus, or Gonorrhea treated?
6
votes
1answer
264 views

How do ribosomes contribute to their own synthesis?

In other words, what products synthesized by ribosomes are actual parts of ribosomes (if any)? How are they involved in their own synthesis otherwise? What is the cycle/chain of products starting ...
13
votes
2answers
251 views

Percentage of genome devoted to regulating gene expression

Recently I've been studying the p53 tumor suppressor gene as a model for regulation of gene expression. It's amazing how many different post-translational modifications are known to regulate p53 ...
19
votes
1answer
401 views

Regulation of chromatin structure

Recently, I reviewed the different levels of chromatin structure. The primary level is nucleosomes, where DNA is bound to histones, and has structural similarity to "beads on a string." The secondary ...
7
votes
1answer
398 views

Which human body hormonal systems exhibit 24 hour diurnal cyclical activity?

I'm researching the possible connection between the dream content and the activity of various organ or hormonal systems within the human body. I'm looking for information on biological cycles within ...
4
votes
1answer
216 views

Why dont “growing degree days” have units of degrees Celsius (or do they)?

From Wikipedia: Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, ...
7
votes
0answers
91 views

Pancretic Acinar Cell - ATP, calcium concentration data

I need to find a decent source of data for concentration of ATP and calcium in the pancreatic acinar cell. So far all I can find is ATP or calcium 'levels' based on fluorescence , which are not ...
9
votes
1answer
2k views

Why can hair grow without limit while eyebrow cannot?

I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit. Why can hair grow without limit while eyebrow cannot?
8
votes
3answers
156 views

How is the sequenced genome of a person useful to him in practice, now?

Currently it is possible and not so expensive for a person to have his genome. This is useful in general for understanding how life works. But, in practice, how is this useful for the specific person ...
6
votes
2answers
65 views

Is there a binding affinity metric for interactions not in equilibria?

I am investigating the strength of binding of a small peptide to a protein by isolating the bound version and subjecting it to collisions with gas molecules (CID mass spectrometry) to dissociate the ...
5
votes
2answers
139 views

How to typeset gene regulatory networks

I have a relatively simply gene regulatory network I would like to visualize, complete with the common arrow and bar symbols used to show, respectively, which genes enhance or repress with other ...
5
votes
2answers
87 views

Why do glial cells of the retina become more abundant the closer they are to the optic nerve?

I am doing a project on expression of GFAP in the zebrafish retina. GFAP is a marker for glial cells. I have found that the glial cells are more abundant the closer they are to the optic nerve at the ...
9
votes
2answers
155 views

What is the least costly method to generate sequential amino acid deletions?

I'm looking to generation sequential deletions from a gene of interest. The total size of this region is 8 amino acids. I'm trying to determine which portion of this region is necessary within the ...
6
votes
1answer
121 views

Ideal low-protein binding membranes

I'm looking through the literature on the topic. It seems like hydrophilic PVDF membranes are ideal for low-protein binding but it also sounds like Regenerated Cellulose is an appropriate ...
8
votes
1answer
103 views

Is bootstrapping an acceptable way to determine standard error for binding constants?

I'm measuring binding constants my system and I appreciate the usual methods of using replicates to measure standard errors and using those errors to calculate propagation of error. I'm curious if ...
7
votes
1answer
1k views

How does one calculate the resolution of a crystal structure?

Considering that I have a diffraction pattern of a crystal, how would I calculate the resolution of a structure in Angstroms? How does that value differ from the information that I would get from the ...
8
votes
1answer
755 views

How strong is spider silk?

Spider silk is pretty darn strong and all sorts of comparisons are made to steel. I'm more curious about the various moduli of spider silk and how it compares to other materials. What is the Young's ...
5
votes
1answer
237 views

Stabbing muscles when flexed and when relaxed

Just a random question, would a sharp object pierce your muscle more(stabbed with the same amount of force) when the muscle is flexed or when relaxed?
8
votes
1answer
117 views

How would a warm winter affect maple sap production?

The past winter (2011-2012) was warmer than usual. Trees are normally tapped in late February when the daily maximum temperature goes above freezing. However, assuming that there have been ...
15
votes
1answer
371 views

What is the lowest pressure at which plants can survive?

What is the lowest pressure at which plants can survive? How the plants behave in a Martian-type atmosphere? Is there any plant that can survive such atmosphere? Can a lichen grow at Martian ...
12
votes
5answers
4k views

Can any protein be phosphorylated?

I am working with an Arabidopsis mutant with an F-box protein knocked out. It has been shown that F-box proteins targets must first be phosphorylated (Skowrya et al., 1997). I have heard of ...
6
votes
2answers
201 views

PCR amplification and error propagation

Say I have one dsDNA that undergoes normal PCR (where amplification is exponential). If there is a mistake, say a G is swapped for an A during the 2nd round of replication, what percentage of the ...
4
votes
1answer
207 views

What is the molecular mechanism of cystine bond formation?

My bioinorganic and redox chemistry isn't up to par and I'm having a very difficult time understanding the chemical mechanism behind cystine bond formation. Most reactive environments are actually ...

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