Thursday, November 11, 2010

the first case of intracellular symbiosis

From World...

A clue about the single-celled alga Oophila amblystomatis can be found in its name: It means "salamander egg lover."...these algae have been known to enjoy a mutually beneficial relationship with the offspring of the spotted inside the egg sac of the embryos, which grow more quickly because of the oxygen and carbohydrate produced by the algae during photosynthesis. In turn, the algae feed on the nitrogen-saturated waste of the embryo. have scientists noticed Oophila lurking inside the embryo itself—in its very cells...speculate that the algae are passed directly from mother to egg.


At November 11, 2010 at 2:17 PM , Blogger William Lang said...

I recall reading about an experiment done some time ago involving, if memory serves, a bacterial species that was introduced into a certain amoeba species and ended up forming a successful symbiotic relationship; a new "species" was formed—the bacteria and amoeba became depended upon each other, and when the amoeba divided, the daughter cells contained the bacteria.

Apparently, this kind of symbiosis is important in evolution. In biology, there are (essentially) two kinds of cells, prokaryotic and eukaryotic (with or without a nucleus). The latter cells are the kind all plants and animals are made of; the former are represented by bacteria. Eukaryotic cells are extremely complex compared to prokaryotic cells. It's difficult to understand how such complex cells could have evolved. But a big hint is the discovery that some of the structures (organelles) found in eukaryotic cells bear a strong resemblance to certain kinds of bacteria. For example, the chloroplasts found in algae cells bear a strong resemblance to cyanobacteria, which contain chlorophyll (they do photosynthesis). The mitochondria found in most animal and plant cells resemble another bacteria species (I forget which one). So the surmise is that modern eukaryotic cells originated as symbioses between various bacterial species, before multi-celled organisms appeared a billion or more years ago.


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