CharonY

I am not sure what is meant by .I guess just poor wording, but I still want to point that the the dye do not associate themselves with living cells due to their (negative) charge. Now, the question is why do you think that you are overcounting? Is the background too high (trypan blue tends also to stain the serum a bit)? Or maybe do you need a higher dilution?

In both cases as many as needed. Though in field it may be more limited. To ascertain whether you got enough N you could do a power analysis.

Stop drinking coffee???

Interesting, actually. I recently had my first lecture in the USA (kind of a different experience than back in Germany). I had the feeling that the students were only interested in those parts that are likely to be tested in the exam (especially calculations). Usually when I asked questions I was greeted with silence (but the person(s) addressed were at least polite enough to remove their ipods before acknowledging that they didn't have a clue). Unfortunately i am stuck with a basic chemistry lecture (with over 60 students) which does not give me enough freedom yet. I hope I can give an advanced seminar at some point (I will try running around more).

Both theories explain all experiments, so that means that the experiments conducted by the first guy did not exclude the explanation as proposed by the second. Depending on the research one usually tries to exclude as many possibilities as possible in ones experiments and has to include those explanations that could not be disproved with the experiments. In other words regardless who did the experiments, the first guy has to concede that the second explanation could be correct and the next set has to be conducted that apparently is able to distinguish between the two. Happens quite regularly in biological papers. In order to publish the second guy usually would have done the experiments to disprove the first guy first, though. In fact, in one of my first papers I pretty much did that.

It is basically old news. I am aware that this thread is kind of spam regarding to some (I assume Bollywood) movie in a completely different context, but as it claims to be correct, I feel compelled to correct some points . This is wrong. Other body fluids with high concentrations are vaginal fluids breast milk, cerebrospinal fluids, amniotic fluids and synovial fluids. While one seldom comes into contact with the latter, it may prove to be a danger to health care specialists. This is not correct (or rather has not been established as that). It denaturates quite quickly, but there is no way to determine whether it loses infections abilities in few or less than a second. The low concentration is the primary point. Also, fluids in which the virus is present in higher concentrations (e.g. blood) might remain infectious even after exposure to air for some time. The reports are in hours, clearly not in milliseconds. I also want to point out that Air itself does not kill (or inactivate) the virus per se, but rather the drying process denatures it. See above. This is partially right but at the same time wrong in several accounts. It is correct that the virus denatures in low pH. However, lesion in the mouth are rather common. Drinking blood and semen therefore poses a health risk. Also breast milk may be infectious to babies. Additionally, the pH gives no indication of the corrosive strength of an acid. You have also to regard the concentration. The molarity of stomach acid is roughl 0.1-0.2 M. There is no way in hell you can burn your fingers with it. At around 5 M you will notice irritations and maybe itching (especially if you skin hast go small lesions). Not necessarily, under lab conditions at least on researcher managed to get himself infected while transferring blood via a needle. A process under air which takes far longer than one second. Or think of transmission via infected needles among drug users. Implying that needles are not infectious is dead wrong. Despite air exposure not all blood dries up in the syringe.

Oh wow. Now I remember why I never check out the pseudoscience threads.

Minor comment, I would put microbiology and immunology into the biology section rather than the medical one. At least the posts there are rarely of really medical nature.

No, Xgal is dissolved in dimethylformamide, pH does not play a role. You did not use water, did you? I think I recalled that my stock solution also was yellowish, but it was rather highly concentrated. What was your concentration? And yes, this would be something to discuss with your supervisor. It is important (from the viewpoint of the supervisor) that the students communicate and give feedback.

The additional incubation at 37 (not 47!) is for enrichment.

I am also a fan of simple black on white. No background.

Almost, but not quite. Activation (or inhibition for that matter) by posttranslational modification are normally not considered to be allosteric regulation. Allosteric regulation is characterized by binding of a ligand at a specific site of the enzyme that is not the active site. Again, it does not refer to a modification of the enzyme itself. Moreover, "inhibiting" refers to all means of inhibition (of which allosteric is but a subgroup) , what is meant in the OP is probably "competitive inhibition" vs. allosteric inhibition. Note that allosteric regulation can be both activating as well as inhibiting. Competive modes of regulation are, per definitionem, always inhibitory. Also I should add that the binding of the ligand to the allosteric site leads to confirmation changes resulting in activation/inactivation of the protein. Binding of a competitor blocks the active site, but does not necessarily result in larger confirmation changes.

While it is a nice, easy to read book, it is not really a textbook about genetics (or a textbook at all, for that matter). "Genes" (Lewin), was a nice book, IIRC.

To date, those distinctions are more or less arbitrary. In theory one could try to define it properly, e.g. utilizing whole genome information instead of just picking out specific traits. This however, would still require an enormous amount of money (for sequencing as well as the computational part). With the decline of sequencing costs on next-gen systems (around 10-20k to sequence a smallish prokaryotic genome), it may still happen in our lifetime.

If you are asking whether inoculation of in BHis is a prerequisite for a coagulation test, then the answer is no. However it is easier to have a liquid culture to do the test as you can easier add a defined amount of your culture (from BHis in this case).

Appraisal? As in putting a price tag to it? Well, once they are used they drop radically in price. You may want to check out Chemglass (http://www.chemglass.com/) or any other lab equipment company out there.

Well, unless he showed a example in his lecture you would have to ask the following questions: - which carboxypeptidase? -what is its activity under the given conditions? -how many units enzyme are used and what is the concentration of the peptide?

At which wavelength did you do the measurements?

Question: are you the author of the original blog?

This sounds like homework, but it is lacking essential info. Carboxypeptidases are a broad family of peptidases with different specificities. While they can only attack from the C-terminus (hence the name) you just cannot expect a homogeneous digest every 30 seconds or so.

Actually I am pretty sure that the endosymbiotic theory primarily explains the history of mitochondria and plastids. Some other organelles (like the above mentioned flagella and cilia or peroxisomes) where at one or another point also discussed to be the result of endosymbiosis, however to my knowledge there is no real evidence for it.

While population is a great resource it requires heavy investments (e.g. in the educational system). They are now pouring money into it, but as it is true for basically all countries, it is not easy to find a good educational system.

Simply put because of the relatively low output from Chinese institutions. Only in the last decade or so did they really put up speed. Also, if you check the Chinese nobel laureates I am sure that you will find them doing their research in the USA. China is trying to get back top scientists (a similar problem that Germany faces, albeit for different reasons) and is recruiting aggressively. But again, the infrastructure is still lower than that of the ones that I would count to the leading nations.

What equipment do you have access to and do you just want to quantify them, or really identifying them? In the latter case you probably need an MS or a tandem/MS.

There are far more examples than that. A gene does not control the behaviour per se, but a limited number of proteins (including genes involved in metabolisation of neurotransmitters, receptors, channels, etc.) working in concert are necessary for any behaviour. It is easy to imagine that even minor changes in one of these (e.g. a GABA receptor) can result in distinct behavioural changes.