georgeskohler

Argh, I wish we could just conserve our resources better! Oh well...

maybe what you are saying is not so far-fetched...I mean people do get genetic counseling about possible disease risk for offspring should a couple decide to have kids, right? But can you "breed out" diseases? Also, there are genetic factors that likely contribute to disease that interact in ways we don't understand/cannot predict, but maybe it will work I don't know.

Can someone explain what the main differences are in functions of cytotoxic T cells versus natural killer cells (...and are there also "natural killer T cells")? Is it right that NK cells recognize virally infected cells by reduced MHC I expression because the infecting agent takes over host machinery so the host makes less proteins? And do cytotoxic T cells kill cells presenting viral peptides in MHC I? I am confused...also do they both kill by releasing cytotoxic granules into the infected cell, or what is the mechanism?

It's a really complicated topic. Cells receive signals from other cells around them which tell them to proliferate or not to. One example of this is a growth factor produced by one cell can bind to a molecule on the surface of another cell, which tells that cell to proliferate. Cells have to replicate their DNA prior to dividing and the telomeres on chromosomes get shorter with each division. This is partially prevented by the telomerase enzyme, but ultimately normal cells will enter into a senescent state and won't continue to proliferate. One mechanism cancer cells get around this is by expressing more telomerase and inactivating proteins such as p53 whose normal function is to prevent uncontrolled proliferation. So, I think if you tried to reactivate telomerase, you could run into problems.

my thinking is on the one hand, most cells lose telomerase expression and telomeres can get so short with each cell division that eventually the cells cannot transmit the genetic material to daughter cells. hmm, what happens if you reactivate telomerase--cancer cells do this...

did you design the plasmid correctly? does expression of the protein have some deleterious effect?

good point, I guess both why medium with limited nutrients which basically starves the yeast causes that from a mechanistic standpoint and the potential adaptive significance (maybe spores are hardy and can survive the lack of nutrients and then enter into normal growth phase when nutrients are available again...) I know yeast can exist and be propagated in haploid or diploid form in culture.

in terms of dedifferentiating cells, we have turned adult somatic cells to induced pluripotent stem cells, and can differentiate these cells to many different cell types. Also, I think there is some value in showing we can synthesize a known chromosome--maybe down the road it will contribute to our understanding of chromatin structure...

oh yeah, agrobacterium...that's the one that forms that makes trees look all funky?

There was a whole issue of Science dedicated to the idea of capturing and storing CO2 that is emitted when we burn fossil fuels. Is our best option to pursue this strategy while continuing research on alternative energy sources? I understand the need for this I guess, but even if we can minimize leakage from underground storage, etc. to me this just highlights the need to really directly address our entropy crisis once and for all...what do you all think?

I wish I could form a pili and transfer chromosomes to bacteria and see what happens. I think homologous recombination is cool...like mitotic recombination is relatively rare, right? I guess there is recombinational repair. And meiotic recombination can generate cool combinations of alleles for the next generation.

Under starvation conditions (medium lacking nitrogen source) yeast will undergo meiosis to produce haploid spores. Why?

so the innate immune response is all that matters?

I agree.... well, germ cells have only one set of chromosomes, but yeah. It's also cool that small regulatory RNAs regulate gene expression and....other stuff. And then there are cells without nuclei like platelets, and Schwann cells which wrap around axons and that's cool....but I guess irrelevant...what would be a relevant response?

how about mitochondria in humans? okay, so that does not help, sorry!