chlorophyll-a and 1-3-butadiene

Here it is reported the first detection of DV-chl a together with the usual chl a in the marine dinoflagellate Alexandrium ostenfeldii from the Baltic Sea. Growth response and photosynthetic parameters were examined at two irradiances (80 and 240 μmol photons m(-2) s(-1)) and temperatures (15 °C and 19 °C) in a divinylic strain (AOTV-OS20) versus a monovinylic one (AOTV-OS16), using in vivo chl a fluorescence kinetics of PSII to characterize photosynthetic parameters by pulse amplitude modulated fluorescence, (14)C assimilation rates and toxin analyses. The divinylic isolate exhibited slower growth and stronger sensitivity to high irradiance than normal chl a strain. DV-chl a : chl a ratios decreased along time (from 11.3 to < 0.5 after 10 months) and to restore them sub-cloning and selection of strains with highest DV-chl a content was required. A mutation and/or epigenetic changes in the expression of divinyl reductase gene/s in A. ostenfeldii may explain this altered pigment composition. Despite quite severe limitations (reduced fitness and gradual loss of DV-chl a content), the DV-chl a-containing line in A. ostenfeldii could provide a model organism in photosynthetic studies related with chl biosynthesis and evolution.

Topics: Butadienes; Chlorophyll; Chlorophyll A; Dinoflagellida; Fluorescence; Oceans and Seas; Oxidoreductases; Photosynthesis; Temperature; Vinyl Compounds

Treatment of normal green Euglena gracilis with N-methyl-N'-nitro-N-nitrosoguanidine results in permanent loss of the ability to form chloroplasts in close to 100 percent of the organisms. The resulting "bleached" strains can be maintained for over 100 generations; no reversion to chloroplast-containing organisms occurs within this time. Alkylating agents, azaserine, mitomycin C, acridines, nitrous acid, hydroxylamine, and gamma-irradiation do not bleach significant proportions of cells even at concentrations sufficient to kill most of the cells. These results may be due partly to differences in the base compositions of nuclear and chloroplast DNA.

Topics: Acridines; Azaserine; Butadienes; Chlorophyll; Chloroplasts; Cobalt Isotopes; DNA; Euglena; Flavins; Genetics; Guanidines; Hydroxylamines; Lactones; Mechlorethamine; Methylnitronitrosoguanidine; Mitomycin; Mutagenesis; Mutation; Nitrites; Pharmacology; Radiation Effects; Research; Sulfates; Triethylenemelamine