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Perhaps it was the upcoming Asilomar conference or maybe the International Society for Microbial Ecology meeting later this summer. Whatever the reason, the 101st General Meeting of the American Society for Microbiology held in Orlando, June 20-24, 2001, did not have very many presentations that focused on cyanobacteria. Even so, what follows is not a complete list, as I know I've seen others that I can't find in the abstract book right now.
A few presentations focused on marine Synechococcus. Jennifer Sallee, Tara Bayly, and Marcia Marston (Roger Williams U.) described (in different presentations) on one hand the ability of different cyanophage isolates to infect strains of marine Synechococcus and on the other the acquisition of resistance to the phage by the cyanobacteria. Lauren McDaniel and John Paul (U. South Florida) completed the picture of phage-host relationships by relating the rise and fall of lysogenization of marine Synechococcus over the course of a year. Kendall M Gray (U. Washington) reported the isolation of two compounds produced by marine Synechococcus and evidently used by populations as a measure of their number. The compounds appear to be distinct from N-acyl homoserine lactone, a molecule often used by bacteria for quorum sensing.
Cyanobacteria also produce a unique compound, cyanophycin, used as a storage form of nitrogen. Maliha Farooq (Wellesley College) reported on the rate of formation of cyanophycin in cyanobacteria exposed to chloramphenicol and the effect of the drug on polymeric molecular weight. Jane Gwira (Wellesley College) looked at the other side of the equation, the breakdown of cyanophycin when nitrogen is added back to unicellular cyanobacteria. She noted the appearance of a 62kD protease that appears early after the addition of nitrogen.
Times are not always so good, and cyanobacteria must respond to certain environmental stresses. Jesse Dillon (U.Washington) presented on stress factors that affect the synthesis of scytonemin, a compound that protects certain cyanobacteria against UV radiation. Sergei Markov (Marshall U.) also examined high intensity irradiation, in particular the relationship between photoinhibition and hydrogen production and acetylene reduction in cyanobacteria exposed to light of different quality and intensity. Jean Huang (Wellesley College) focused on chemical insults, describing the appearance of a different protease as well as morphological and physiological changes in Synechocystis exposed briefly to low pH. Finally, Scott Miller (NASA Ames) told about the wide range of resistances of PSII to sulfide amongst natural cyanobacterial strains. His analysis indicates that resistance, achieved in different ways, has arisen multiple times within the cyanobacterial radiance.
Evolution was also on the mind of William Martin (Heinriche-Heine Dusseldorf), who gave a most remarkable presentation on endosymbiotic theory. He discussed the origin of the glycolytic pathway in eucaryotes (Eubacterial) and contrasted it with Calvin cycle enzymes (cyanobacterial). William Schopff (U.California-Los Angeles) gave a general talk about the Precambrian fossil record. He showed some nice images of stromatolites and cyanobacterial fossils.
Perhaps the most notable cyanobacterial reference that I encountered was in an odd talk within a section on geobiology. Abigail Salyers (U. Illinois) will be the next president of the American Society for Microbiology. She gave a speculative talk about the health implications of geobiology that was quite provocative, discussing the origin of pathogens and their evolution in non-human hosts or geological systems. One example was cyanobacteria that are implicated in blackband disease in corals. The cyanobacteria have acquired toxins. Could these move to humans and become human pathogens? And then the great quote. Stepping back and trying not to offend anyone, she said that she was not trying to pick on cyanobacteria, and added that clearly over evolutionary time "cyanobacteria have been man's best friend." I agree.