Archive for January 2012
The new cell biology
I have not been a very faithful blogger the last few months – whether that will change in the new year remains to be seen. I travelled more in November than usual and then spent December getting caught up on some book reviews, referees reports etc. that I had been asked for and had agreed to do. Among other things, I have been left with a pile of reading to catch up on. One thing that caught my attention as I began to do so was three related front-of-the-magazine pieces in Nature on December 1st, the first of which here was called “the new cell anatomy”.
Apparently a mixture of biophysicists, cell biologists and biochemists in recent years have been discovering all kinds of previously unknown structures inside of cells. The phenomena and terminology are bewilderingly diverse – various “tubes, sacs, clumps, strands and capsules” including filaments, nanotubes, purinosomes, microcompartments, carboxysomes, exosomes, cytoophidia (cell serpents) – some of which concepts undoubtedly will last, others of which undoubtedly will not. A lot of the discussion has been about the development of new methods as well as of applying old methods to single cells accompanied by a fair amount of arm waving about possible medical and industrial applications.
My point is that I hope in all of this, at least some of the researchers will keep their eye on a different question. As the late Lynn Margulis among others showed – there is a lot of knowledge to be gained about evolution working between the cell and the molecule, including by microscopy, newer fancier versions of which play a role in some of the new work. Since nobody thinks that life began de novo with prokaryotic cells fully formed, and since evolution always, always leaves marks of its history, there surely is a lot to be learned about the origin and early evolution of life by peering into, prodding and manipulating existing cells. So I very much look forward to eventually hearing more about the implications of the new work for that subject.
Why is my organic (kitchen) waste so heavy?
Like many cities in the developed world these days I suppose, mine has a recycling programme. Basically, organic (kitchen) waste is put out in one can once a week for composting; cans, bottles and paper in another every two weeks for recycling; garbage in a third every two weeks as well for disposal; and garden waste seasonally in paper bags. In our household, the first two are accumulated in similar sized plastic bags in containers in the kitchen and put out in the cans every once in a while, while the third is put out bagless in the third can more frequently as it accumulates. Now here is the puzzle. Whenever I happen to put out the first two at the same time, always in similarly sized bags and therefore similar in volume, the organics for composting are always, always heavier than the garbage for disposal, and by quite a lot. Every time I wonder why that is. Some possibilities might be:
– it’s just idiosyncratic to our household. I suppose if we were repairing cars and disposing of scrap metal (not that anybody would be, scrap metal is valuable these days) but if for the sake of argument we were, it would be different. But I doubt if our experience is unique (otherwise I would not be wondering about it here!)
– biological organisms need protection against antagonists, parasites and predators, hence the denser (from our point of view, waste) – thick skins, peels etc. as well as needing to reproduce – seeds etc. I doubt if that is the answer either. After all, a lot of our garbage is in fact protective – various kinds of non-recyclable packaging like the tissue thin plastic bags that bulk foods and produce are put in and some heavier packaging which have properties designed to persuade you to purchase it, i.e. to serve its reproduction.
-culturally-evolved processes have become more efficient than biologically-evolved ones. Now that is an intriguing possibility.
– finally my (originally an engineer) husband’s suggested answer is that the organic material is wet and water is heavy. Hmm – this possibility admits of an experimental answer, if we dried out a bag of organics would the weights be similar? I have never been much of an experimenter but . . .
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