Jump to content

CharonY

Moderators
  • Posts

    13261
  • Joined

  • Last visited

  • Days Won

    149

Everything posted by CharonY

  1. I would say that unopened cola would be virtually sterile. During the manufacturing process there is little which promotes growth, and the things in there, like the pH (phosphoric acid) and high sugar content (close to 200 mM based on rough calculations) would be stressful to most cells. Opening it up would be a different thing, though. Still, osmotic and acidic stress for most, and I am not sure whether there may be additional nasties in it.
  2. Dude, you are still operating under the wrong assumption what junk DNA is. It was very well known that gene expression is dependent on stimuli and is necessary for cell differentiation. Just following logic, how the heck are cells supposed to differentiate when there are no expression differences. Also, gene expression analyses have been done for ages. This would be quite futile if there were no differences to be expected, no? Also non-coding DNA with regulatory functions are VERY well known. How, do you think, is transcription regulated (textbooks may help you here). A surprise were the detection of functional sRNAs (they were simply not known as class and have not been detected). Seriously, read a basic genetics textbook and then we can discuss some more. I see little value in discussing erroneous assumptions.
  3. I assume that the transferable diseases were mostly parasites (as ewmon mentioned) as well as a number of viruses. Bacteria tend to be somewhat less specific in that regard.
  4. It is hard to tell from the description, but the failure of DAPI is suspicious. First, are you sure the microscope is working? I.e. even without stain you can see your cells well in transmittance light? And second, the cells are Ok?
  5. Knockdowns are very useful.
  6. Actually evolution does not consider individuals per se (selfish genes are mostly interesting in terms of specific mechanisms), but always focuses on the population. The key is allele frequency. They are, by definition a description of the state of the population. There is no individual resolution. From that standpoint individual changes are almost always relatively inconsequential, with few exception. This may include extremely low population sizes, or enormous selective pressures, which would rapidly increase the frequency of the involved allele(s). Again, evolution is all about population changes. Not about individuals. Actually, certain teleological elements in the broadest sense are somewhat possible. For instance, loss of certain functions may lock the future direction of a species (if the re-occurence of the mechanism by whatever means is highly unlikely), especially assuming an otherwise constant environment. Under these conditions (and probably some more that I did not think of right now, like e.g. the proportion of fixed alleles in the gene pool and whatnot), the possible directions of evolution may be limited to such a point that a certain endpoint appears inevitable. Though I probably would not call it teleology in the classical concept (i.e. final cause) as it is more the consequence of certain mechanisms (or lack thereof). It would be a bit akin to invoke teleology to explain gravity, for instance.
  7. Regarding non-expressed genes. This is what physiologically is expected from about every cell. Not even in prokaryotes can anyone expect to see every gene to be active. They are regulated by internal or external stimuli. The basic premises in the OP are simply wrong.
  8. Actually I remember that at least in many of the more famous battles the mongols were numerically inferior and were victorious due to superior tactics. They excelled in the use of flanking tactics, though. Eventually this could result in encirclement.
  9. Not as the OP describes it. Here: Junk DNA is clearly referred to genes that have no function in a specific cell type (as opposed to another). Also note, while there are genes that are not expressed anymore in certain tissues, they may have very well been active during differentiation. Also this is not quite accurate .It would only be surprising if the additional DNA came at a cost with no benefit. This appears to be somewhat true in e.g. prokaryotic and, even more pronounced, in viral genomes, where DNA size places a considerable cost on the organism. However, in eurkayotes genome size is much less limiting. So even in absence of benefits an increase would be considered neutral or near-neutral. Viral resilience have been put forth relatively early to explain an expansion of genome sizes in eukaryotes and, as mentioned, quite a bit of the junk DNA can actually be assigned to regulatory or structural functions. Once the cost restraint of DNA was lifted in higher eukaryotes expansion of genome size could lead to benefits that overcome the (in eukaryotes) relatively low additional cost for DNA synthesis.
  10. If they gave me some samples I could run it through the MS for a few bucks.
  11. Don't have much time but there are a number of factual errors in the OP: This is not what junk DNA is. Essentially they refer to non-coding regions (though with the discovery of sRNA this has to be expanded somewhat). Genes that are silent (in a given tissue) are not junk DNA.
  12. Article A few things that need to be noted. First the described process itself is a very dangerous process and can lead to death, as such, it is most likely not a very appealing therapy in its current form. In addition it requires compatibility as well as immunity of the donor, which further limits practical application. Also, it would require quite some more time to establish whether the virus may still be present. Other than that, very interesting. that such a brute force method appeared to work.
  13. Because lending money to sick people does not give enough profits and especially in case of critical medical treatments it is not clear whether it will be paid back at all (if the patient dies, for instance). A car can be impounded. It is slightly tricky with livers, for example.
  14. Standard protocols for biological samples is dry weight measurement using moderate temps (often around 65-85 ° to avoid loss). Depending on application freeze drying is also an option.
  15. As mentioned elsewhere, the paper mostly demonstrated high resilience of an organism to As, rather than living off it.
  16. You cannot get the size accurately of uncut plasmids (at best you can approximate using other plasmids with known size). Now you got a semi-log of size over migration length of linear DNA fragments. How would you use that to read out the size? Tip: use the only remaining other parameter.
  17. Also in what area? The best hospitals are usually highly specialized in a specific field. E.g. cancer treatment, cardiovascular diseases, infectious diseases, etc. There is unlikely to be a single country filling all the top spots, though.
  18. I would think that this is somewhat irrelevant for broad comparisons as e.g. between countries. It is almost a no-brainer that there are variations within a country (and yes, there is a study for that, not committed to my memory, though). The goal of country-wide comparison are not to find out which hospitals are the best, but rather whether there are elements (infrastructure, funding, policies, accessibility etc.) on a country-wide basis that affect the health of the respective population. The spread is more interesting to look within a country which local elements pertain to the spread. However, there was at least another study that compared infant mortalitiy in different cities around the world. What they focused on were socio-econmic disparities and found an inverse association with infant mortality and income in an US city (and also maybe in one European one), but I remember that at least in Paris and Tokyo there were none (forgot the other cities, could be London and New York). The strongest was found in the US city though. This is one example of a comparison on the microscale.
  19. What you are looking for is the meninges.
  20. Well, an epi-study without statistical evaluation would not be worth much, would it? But fair enough, I did not quote the statistical analysis. They calculated rate rations and the 95% confidence intervals and for each cause of infant death, which includes congenital anomalies, injury etc. the rate was higher in the USA (within the mentioned CI) with the exception of maternal complications at term. There was another study focusing on socio-economic factors, but I would have to dig for that.
  21. I think, i commented on ti elsewhere already, but it has to be noted that the bacterium does not have an arsenic base. It only has been shown that it is able to incorporate a lot of arsenic, including levels in which P has presumably been exchanged by As (this has mostly been demonstrated indirectly). Moreover, the data is not perfectly clear on whether the cells really utilized As for growth or e.g. managed to do it in presence of the limited P still present (or released from the increased rate of dying cells). At least that was my impression after a quick read a while ago. I still have not gotten to re-read it in more detail, but this paper has been criticized heavily elsewhere. I still consider it a very interesting finding, however, it is not a demonstration of an organism with an As base.
  22. There are comparisons like that out there. One that I had saved was between Canada and the US: Ananth et al. Int J Epidemiol. 2009 Apr;38(2):480-9.
  23. An analogy with skeleton and muscles is probably not very helpful, as the cytoskeleton itself is involved in movement. Actin is involved in maintaining cell shape as well as movement, as pointed out above. Microtubuli are also participating in cell shape, but also are part of intracellular molecular movements. Membranes and cell walls are also elements of cell stability, and so on.
  24. I do not think that you got impurities. First, minipreps generally result primarily in OC, CCC plasmids and then you got multimers (but still closed). So additional higher MW bands are perfectly normal. Linear DNA tends to pop up if some mechanical nicking occurred. From the gel it appears that the additional band is only seen in the phosphatase treated sample? Because the digest alone looks perfectly fine (is it the expected size)?
  25. Isopropanol and ethanol are realatively close in terms of their dissolution ability. Ethanol is slightly more polar and more salt tolerant. However, for cleaning purposes denatured ethanol should be used (due to cost issues). I have no idea why a well-equipped lab is insane (well, two bottles is rather poorly equipped, actually).
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.