4
votes
1answer
148 views

Is a raised baseline between T and QRS normal in any ECG lead?

Here are excerpts from an unknown ECG lead. I find it weird that the "baseline" changes after the T wave and doesn't return until after the following QRS complex. Is that normal/expected for any lead? ...
15
votes
3answers
254 views

Defining paper(s) in epigenetics

For someone who is interested in learning about the discovery of epigenetics, which are the foundational defining papers in the area?
14
votes
6answers
1k views

Online Molecular and Cellular Biology Video Lectures?

I am looking for video lectures to go through to guide my reading in intro molecular and cellular biology. I've had intro bio and I study evolutionary theory, but my molecule- and cell-level knowledge ...
8
votes
1answer
85 views

Which aspects of renal physiology are standing in the way of an artificial (mechanical) kidney?

Scientists have been able to create artificial organs with varying degrees of success. The mechanical heart (in its various forms, e.g. ventricular assist) is able to sustain life for some period of ...
30
votes
4answers
688 views

How does the sensitive plant detect vibrations?

The sensitive plant (Mimosa pudica) is a remarkable little plant whose characteristic feature is its ability to droop its leaves when disturbed: Apparently, this ability to droop rests on the cells ...
9
votes
1answer
99 views

Last-ditch efforts to maintain thermal homeostasis

I was in the gym's steam-room today and a thought occurred to me: have I truly thwarted all possible mechanisms for maintaining thermal homeostasis? There's sweating, which is thwarted because the ...
12
votes
1answer
563 views

How many people's DNA were involved in the compilation of the reference human genome?

I know that the reference human genome is complied from DNA portions from different people, most of whom were European. Do you know how many of them were involved? Do you know which ones were ...
40
votes
2answers
1k views

Is there any evidence that sexual selection may lead to extinction of species?

Darwin suggested that sexual selection, especially by female choice, may counter natural selection. Theoretical models, such as a Fisherian runaway process, suggest that evolution of preference and ...
19
votes
2answers
97 views

How is duration of efficacy estimated for vaccines?

Vaccines, especially those given in adulthood, usually have term limits attached, eg: 10 years for yellow fever or 3 years for typhoid. Since presumably the time course of an immune response is no ...
23
votes
4answers
496 views

How are the boundaries of a gene determined?

What statistical processes and methods are used by geneticists/molecular biologists to know where one gene starts and one ends?
25
votes
4answers
3k views

Do plants produce any heat?

Many plants (e.g. roses, palms) can be protected from frost during the winter if shielded with an appropriate coat that can be bought in garden shops. Do plants produce any heat that can be kept ...
9
votes
1answer
135 views

What are the criteria for determining the influence of epigenetic factors?

Isolating a gene or sets of genes in diseases sometimes isn't enough to determine penetrance - epigenetic factors can have a significant effect. What are the criteria in determining whether epigenetic ...
7
votes
1answer
227 views

Mechanism of syndesmophyte growth in AS

Ankylosing Spondylitis (AS) causes inflammation around joints and the growth of syndesmophytes that may eventually fuse vertebrae. I'm familiar with the genetics (HLA-B27, IL1A) related to the ...
2
votes
1answer
74 views

Substrates of cytochemical reactions in this immunostaining

Expression of extracellular protein Laminin 9 alpha-4 chain in human skeletal muscle. Indirect immunostaining with HRP immunostain marker. Ob.x40. I have unsuccessfully searched NCBI -database, JSTOR ...
7
votes
2answers
485 views

Where does vasoconstriction occur in limbs?

When cold or in shock a person's blood vessels constrict in order to preserve heat or to move blood flow to protect vital organs. I am interested in the mechanism by which this is achieved. Does ...
15
votes
3answers
799 views

Are single-celled organisms capable of learning?

I've read that the amoeba is capable of learning. Since these protists have no nervous system, it's safe to assume that even highly simplified learning mechanisms of the Aplysia are miles off in the ...
11
votes
1answer
191 views

Are there any pre-Holocene venomous animals?

The novel (and subsequently movie) Jurassic Park featured a dinosaur called Dilophosaurus, that was purported to be venomous and had an ability similar to that of the extant spitting cobra. ...
17
votes
2answers
300 views

What are the major evolutionary pressures for Bioluminescence?

What are the major evolutionary pressures for Bioluminescence?
33
votes
1answer
14k views

Why Does Salt Water Help Sore Throats?

I am having some trouble understanding how salt water, a simple solution, could so effectively remove the pains of a sore throat. I do believe that the answer is closely related to hypo/hyper-tonic ...
7
votes
1answer
171 views

Are cerebellar basket and stellate neurons actually different cell types?

The title more or less says it all, but to contextualise a bit: Cerebellar molecular layer interneurons have been classified, probably since Cajal, into the basket cells, which synapse onto the soma ...
25
votes
3answers
394 views

Is telomere length a reliable measure of health/lifespan?

Several companies are commercializing tests for telomere length such as this one here. I understand the basic mechanism for why telomeres shorten during DNA replication, but how good is the evidence ...
9
votes
2answers
83 views

Recommended applications for commercial antibodies

Commercial suppliers of primary antibodies for given protein targets typically list recommended applications, for which the antibody has presumably been shown to work. I am usually looking to use them ...
8
votes
1answer
190 views

Does the oxygen concentration equilibrate between red blood cells in the liver sinusoids?

In the sinusoids of the liver, venous blood from the hepatic portal system mixes with arterial blood from the hepatic arteries. Do oxygen molecules move between oxygenated RBCs and non-oxygenated ...
10
votes
2answers
141 views

Is there an equivalent to “Fields Virology” for Bacteria?

I've gotten a staggering amount of use out of my copy of Fields Virology as a general reference for "getting me up to speed" on whatever pathogen I'm currently looking at. I don't know of a similar ...
14
votes
1answer
132 views

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

So I'm looking for some information on the infectious dose necessary to colonize a human with Clostridium difficile. There's no human challenge studies, and since it's not a foodborne pathogen, little ...
7
votes
1answer
68 views

What is the effect of exendin on beta-cells

Do you know if exendin, an analog of GLP-1 (glucagon like peptide-1), can be toxic for beta-cells? For example what is the effect on INS1 or Min6 cells at a certain concentration or after 90 mins of ...
8
votes
2answers
912 views

How much time do INS1-E and MIN6 cells need after splitting?

I am currently doing an experiment on cells to test the internalization of a protein. Normally, I seeded my cells the day before the incubation. This worked well for Hela, CHL or PANC1 cells. However, ...
6
votes
1answer
165 views

How Do Large Ocean Viruses Form Their Own Organelles?

Several large viruses (Arslan 2011) form their own organelles within the amoebae they invade. How do these organelles form? Reference: Arslan, D., Legendre, M., Seltzer, V., Abergel, C., Claverie, ...
50
votes
3answers
25k views

Why is uracil used in RNA rather than thymine?

What is the advantage gained by the substitution of thymine with uracil? I have read previously that it is due to thymine being "better protected" and therefore more suited to the storage role of ...
9
votes
2answers
509 views

What is causing my problem with very low yields when isolating a 42kb yeast plasmid?

I have to isolate a large plasmid from yeast and transform it in E. coli. After transformation, I often get no colonies. One reason for that is the yeast mini prep hasn't worked or the DNA ...
9
votes
4answers
1k views

What determines a successful protein expression in E. coli?

Some proteins express well in a heterologous host; others- don't. A few requirements are known to determine the protein expression, like a strong promoter (like T7) for transcription and a strong ...
13
votes
2answers
278 views

When does BLAST fail to align 2 DNA sequences?

This is an assignment that had confused me for a long time. So I think you guys who study computational biology might be interested. The original question is: Find the two most similar DNA ...
24
votes
2answers
358 views

How do biological communities at deep-ocean hydrothermal vents migrate between vents?

Much interest in the astrobiology community has been generated by the discovery of biological communities populating deep-ocean hydrothermal vents (i.e. "black smokers"). (1) These ecosystems rely on ...
17
votes
1answer
196 views

Are there dextral/sinistral higher animals?

For example, almost every dog I've met in my life (more than 20 subjects) uses their right paw touching one while asking for attention. Can it be used as a criterion for calling them dextral? If not, ...
9
votes
1answer
104 views

Why is there an extended delay before G.M. liver cells are attacked by the immune system?

In this BBC article a trial is described where patients with B-Haemophillia are infected with modified Adeno-associated Virus 8 which contained the genes for Factor IX clotting protein. Trials seemed ...
6
votes
1answer
280 views

How can I keep HEK cells alive while expressing NMDA receptors?

I am trying to express functional NMDA receptors in HEK293 line cells for single channel recording experiments. The HEK cells are maintained in the standard way (Thomas & Smart 2005) and ...
15
votes
1answer
586 views

Can siRNA induce DNA methylation in mammalian cells?

Some years ago Hiroaki Kawasaki and Kazunari Taira published an article called "Induction of DNA methylation and gene silencing by short interfering RNAs in human cells" in Nature: In plants, ...
9
votes
1answer
251 views

What are the olfactory chemicals in whiteboard/permanent markers and what do they bind to in the nose, lungs, and brain?

What are the olfactory chemicals in whiteboard/permanent markers and what do they bind to in the nose, lungs, and brain?
6
votes
1answer
115 views

Latency to audition in human beings?

On average, in a human being with no neurological deficits, how long does it take for a sound which is sensed in the ear to reach the cortex? Which brainstem structures are most responsible for the ...
12
votes
2answers
402 views

What is the morphological difference between Leydig cell in human and pig?

The pig is only an example, just an animal. Leydig cells have protein inclusions (Reinke crystals) that are mostly made of crystallised lipofuscin. They are secretory inclusions i.e. cells formed in ...
5
votes
4answers
1k views

What are good resources for self-learning modern molecular biology concepts? [closed]

My learning of molecular biology ended in the early 90's (and with early 90's era information). While I don't aspire to be a molecular biologist, I do aspire to better understand modern approaches ...
6
votes
2answers
761 views

How do I prepare and clone from E. coli DNA?

I'm looking for a protocol to get genomic DNA from an E. coli sample so that I can clone a small portion of it using PCR into a plasmid. (< 500 bp in this case). It seems OWW (Open Wet Ware) ...
9
votes
1answer
739 views

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

I would like to perform a modified co-immunoprecipitation assay using a GFP-tagged protein. We are going to bind the tagged protein to anti-GFP antibody then bind that to protein A/G beads, however ...
7
votes
4answers
158 views

How can I produce milligram quantities of an isotope-labeled DNA oligomer?

I'd like to produce a specific DNA sequence on a milligram-scale and 13C15N-label it. The sequence is around 35 nucleotides long, so chemical synthesis is out due to the exorbitant costs. I'm also ...
18
votes
3answers
383 views

Good source that explains the evolution of single-celled organisms “from scratch”

Are there any books or sites that detail, step-by-step, the evolution of the first single-celled organisms (bacteria, archaea) from a Miller-Urey-like beginning? That is, assumes only amino acids, ...
14
votes
1answer
550 views

Do large animals often evolve into smaller animals?

There are several examples where the largest animals were killed off preferentially due to a major ecological shift: The KT extinction event The Holocene extinction, as well as the major megafauna ...
9
votes
1answer
188 views

What are the clotting factors' effect on avascular necrosis development?

Do clotting factors tpa and pai-1 lead to degenerative osteoarthritis in the same way that lupus anticoagulant and prothrombin might? Is one of these pathways particularly detrimental during formation ...
31
votes
2answers
1k views

How do cockroaches resist the effects of ionizing radiation?

Cockroaches are very hardy insects. It is known that, among other things, they are able to withstand bursts of ionizing radiation that would kill a human being. The explanations of this observed ...
17
votes
2answers
321 views

Can an adult without genetic lactase persistence still develop a tolerance for dairy foods?

While investigating the rise of adult lactose tolerance, I came across the news that China has been encouraging its citizens to drink more milk, even though most of the Asian population lacks the SNP ...
5
votes
2answers
1k views

What conditions should I use for Gel Red staining?

What are the optimal staining conditions when using Gel Red? So far, since we have started using it, the gels ran in our lab have been of very poor quality. The bands are very blurred and often ...

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