CharonY

A good news for all the coffee junkies. First it became apparent that coffee is not as strong a diuretic as believed initially. Now a report from Wanke et al. (Mol Mic, 2008) showed that caffeine targets the TORC1-Sch9-Rim15 phosphorylation cascade that is believed to be involved in increasing lifespan in nutrient limited organisms. As this cascade is highly conserved it may also have an effect on humans (the study was conducted with Saccharomyces cerevisae).

Of course. Plants and Animals are different kingdoms within the domain of eukaryotes. That leaves out prokaryotes by default according to Woese's system. To be honest, I am not that familiar anymore of the most recent consensus on classifications on that level (or whether it has been resolved at all). When I studied protista were still used as a taxon, although they were not monophyletic. Rather recently I think there was another proposition in which the eukarya were not only grouped into plants, animals, fungi, and one or several protists group, but in six clusters existed. I actually forgot the names, but according to my memory (so take it with a big chunk of salt), the groups were basically animals and fungi in one group, plants and red as well as green algae in another, then there was group consisting of other algae and finally three groups of mostly or exclusively single cell organisms.

I assume that the diet is adjusted accordingly, of course. A number of amino acids, co-factors and so on are mostly of bacterial origin at some point as many eukaryotes lost the ability to synthesize them. AFAIK the human colon is relatively ineffective in sequestering nutrients from gut bacteria (as compared e.g. to cows) so normally you need another source like vegetables, anyway. Of course if all bacteria on the planet were eliminated we all would die. Well in theory yes. But I would not know how to destroy them, ABs for the most part do not work on them.

While we are at this (well a few months back), one could also argue that Microbiology is for the most part associated with Biology rather then with Medicine. Likewise Neuroscience (in contrast to neurology) and physiology (even if we only concentrate on human physiology).

Guess we will know after the first couple of selective sweeps

Getting rid of them is somewhat possible (it is done during colon transplantation). Most of the time it does not work completely and residual bacteria are believed to be one of the major reasons why such operations are very risky. However, if you lived in a sterile environment and never get exposed to bacteria, then it is quite possible to live without them. Most likely you have to get rid of the rest of the bacteria on your body, too. Interestingly sterile mice even tend to live longer than their counterparts. Of course they die quickly once exposed to a non-sterile environment.

I have to admit that my former high school teacher actually did quite some of Mendelian genetics and statistics, more than required by the curriculum. A nice touch was the inclusion of statistical tests like t-test or chi square. He was an exception though and because a large number of students had very bad marks in these tests he had to stop doing it. Rather sad, actually. Regarding bioinformatics, I am quite interested to hear, what subject your course includes. There is a wide variety in these relatively new curricula. For instance, the Uni where I made my PhD had a very strong bioinformatics department. I have given a week's worth of lectures on applied bioinformatics there (out of a total of four week's course). I was basically giving a talk about algorithms for protein alignment, phylogentic tree construction and pattern finding. I was required to explain mathematically quite a number of the statistical models used in them and I think that course was quite good that way. Then, in an institute during my first postdoc a colleague gave a course about bioinformatics and there he basically showed how to do a BLAST search

Please elaborate on what kind of experiment you talk about. I assume that you did an experiment regarding osmotic stability of red blood cells, but it is usually better if the OP explains the question better (like spelling out RBC). Especially as it is a high school experiment with no standardized protocols. In any case the incubation is indeed needed to for water exchange. However it does not necessarily be two hours. In the simplest case the rate is dependent on the difference of the concentration of solute inside the cell compare to the outside.

Hmm that is a tricky one. The fact that it works for different cell line tends to be a a slightly weak indicator that everything is all right, as some are more susceptible to, e.g. certain contaminations. However if the same protocol suddenly does not work with the same cell line that worked before, that is strange. Especially if you use the same equipment. Disposable plastic wares also eliminate a lot of contamination problems. One final thing that I can think of at the moment is whether you have changed anything on the water system? For instance whether pyrogen and TOC levels are still low. I have not cultivated OVCAR cells myself (the closest I have cultivated are HeLa cells) so I am not 100% sure how sensitive they are.

Do you use glasswares to cultivate them or disposable plastics? Also do you buy the medium or do you make it yourself (are the chemicals fresh?).

Well, but how many curricula do actually do a good thing to teach evolution? Just how many (biology students even) know the difference between the darwinistic the neo-darwinistic theories of evolution and the (modern) synthesis. And to be honest hardly anyone is really sure how to call what is now the prevalent theory (as it has departed somewhat from a number of basic tenets of the modern synthesis). I agree that it should be taught more and deeper, as it is indeed one of the few common themes, but then a lot of people take bio classes to avoid mathematics. Teaching evolution requires a firm understanding at least of stochastic. I gave a short course in simple statistics for graduate students once, because a lot had serious problems with analyzing the data. I fear that it would be worse in high schools.

Funny enough Ecoli as a single word does yield some results. Surprised me a bit. Google scholar is soso for finding articles, but a very good database is web of science. It is not free either, though. Free Journals are ASM-journals (after half a year), BMC and plos, where you can find microbiology articles. I do have the feeling that he/she was asking for general microbiology info rather than science articles. In this case there are a few online resources, but they all cost money. A good textbook would be cheaper in that case.

This is basically correct. It is used to find an optimum concentration or mixture of reagents. It is normally used in ELISA assays (I assume that was your starting point) but in variations it can be used in all concentration based assays on plates. In the simplest case you can imagine one reagent(e.g. primary antibody) diluted 1:1 1:5 1:10 and so on across the plate and a dilution series with the second reagent (e.g. secondary antibody) down the plate. So in the top left (A1) you would have a mixture of 1:1 primary to 1:1 secondary antibody, in the well left to it (B1)1:5 primary to 1:1 secondary, and in the well below the top left (A2) 1:1 primary to 1:5 secondary. If you fill the plate you then can easily see which ratios are in the optimum for your experiment, or you can determine the possible range of your measurement (by using a dilution series of standards) and so on.

Actually I do not have much respect for biology in highschools. What you learn in physics and chemistry there really helps later on if you go to university, but biology is almost always a bit this and a bit that, but not useful at all once you get to university. One the few things that actually have merit are structure of a cell and certain metabolic pathways. At least this is true for all highschool (or equivalent) curricula I have seen to date. I assume that it is partly because biology is so bloody diverse that a real comprehensive curriculum is hardly possible. And if there is no common theme in which you can wrap your mind around it boils down to memorizing stuff. And that does not help in the long run. To be honest though I have little ideas how to improve it. To date I have only given specialized lectures but I have a hard time thinking about a comprehensive curriculum that does not appear like stamp collecting facts. In University you can at least give practical courses, but they take too long usually to implement them in a meaningful way in highschools. Another problem is that many of the "facts" that are taught can be obsolete once one end up in an uni. Knowledge turnover has increased dramatically at least in molecular biological disciplines.

Hmm are you asking about CO2 or nitrogen fixation? Actually it is not that puzzling. Redox enzymes have been around forever (like e.g. in the respiratory chain). While proteins of the respiratory chain most likely first interacted with non gaseous terminal electron acceptors (e.g. iron(III)) It is not that a large jump to reacting with oxygen, or N2. The paper gets more interesting towards the end. It is always tricky to think in that long time frames, especially in fast proliferating organisms. Nature does not care about that, of course (or about anything). But as I said it is likely that a redox enzyme "simply" switched substrate.

I have not read the other thread, but let me barge in uninvited. Natural selection has a an advantage compared to top-down approaches: what works, works. One basic disadvantage of eugenics is that usually a reduction of variance. If the environmental conditions were constant forever and we knew the complete results of any given eugenic approach, then maybe more alleles which increase fitness may accumulate faster. But this is only very theoretical. We do not know hardly enough to actually even try to do that on a population level.

I think I see what confused you. The formula you put forth is the same as wikipedias, the volume of the solution is equal to ethanol and water together. For most intents and purposes a percent solution is simply calculated against a given total volume (e.g. 1l). What you have to take into account is the density of ethanol which is 0.789 kg/l (at 25°). What the calculator does wrongly is probably calculating %(w/v) against a kg instead of an liter. In that case 1l of Ethanol would have a weight of 0.789 kg or 78.9%(w/w) against the 1 kg. But using the density, however, the correct calculation is fairly easy.

Actually it is just a means to get rid of foreign elements. They do not have to be harmful per se to be a target of an immune system. It is kind of a means between self and non-self (and to attack the latter).

Sounds like homework to me. 1) Do you mean whole plasmids? 2) This does not make sense. Do you mean DNA strand? Even so a single DNA strand does not ligate. What precisely, do you think does ligation mean?

Actually why should it not be considered alive? Of course at the current state it cannot replicate. The same goes for caterpillars. Or certain differentiated cells that do not replicate anymore. Well the properties of life are not as dual as one might think (as in life vs dead).

I used to have many dogs, mostly strays, but also 5 chihuahuas. But when I became a phd student and later on postdoc, there was not enough time, I had to leave them to my parents. Also I had three guinea pigs, two chinchillas and three rabbits.

Well, at the moment I got my lab for me alone. But I guess I may have some grad students to teach, soon.

Ah, OK. Reading some of the endorsements I was under the impression that it included original experiments. My bad.

Well it does not need to be fertilized to be classified as living cell. Ovaries are cells, so they are living.

Ow and is anything of its findings published in journal?