[Effect of cadmium on the absorption and excitation energy transfer in cyanobacterium Nostoc muscorum].
The absorption and energy transfer between pigments in Nostoc muscorum by the action of 10(-4) M Cd2+, when the cyanobacterium remains viable, and in the presence of 10(-3) M Cd2+, which causes the death of cells during 3-4 weeks of incubation, were studied. A comparative study by the methods of absorption and fluorescence spectrophotometry at 295 and 77 K, including derivative spectroscopy and deconvolution of emission spectra into a number of Gaussian components, showed that, in the presence of 10(-4) M Cd2+, the energy transfer from phycobilisomes to chlorophyll of photosystem I increased. After incubation with 10(-3) M Cd2+, the energy transfer from phycobilisomes to chlorophyll of photosystem II decreased, and the transfer to photosystem I was absent. New bands in the absorption spectra, in the second derivative of absorption spectra, and in the fluorescence spectra at 77 K of cyanobacterium were observed after 7 days of incubation with cadmium. We belive that these bands are due to the formation of CdS particles and Cd-pigment complexes. The conclusion about the dual effect of Cd2+ on the functioning of the energy transfer chain in N. muscorum was derived.
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Bekasova
A A
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Brekhovskikh
D002104:Cadmium / Q000633:toxicity*; D004735:Energy Transfer; D004785:Environmental Pollutants / Q000633:toxicity*; D005453:Fluorescence; D046937:Nostoc / Q000187:drug effects* / Q000378:metabolism
D004785:Environmental Pollutants; D002104:Cadmium