RRC ID 49205
著者 Nozue S, Katayama M, Terazima M, Kumazaki S.
タイトル Comparative study of thylakoid membranes in terminal heterocysts and vegetative cells from two cyanobacteria, Rivularia M-261 and Anabaena variabilis, by fluorescence and absorption spectral microscopy.
ジャーナル Biochim Biophys Acta Bioenerg
Abstract Heterocyst is a nitrogen-fixing cell differentiated from a cell for oxygen-evolving photosynthesis (vegetative cell) in some filamentous cyanobacteria when fixed nitrogen (e.g., ammonia and nitrate) is limited. Heterocysts appear at multiple separated positions in a single filament with an interval of 10-20 cells in some genera (including Anabaena variabilis). In other genera, a single heterocyst appears only at the basal terminal in a filament (including Rivularia M-261). Such morphological diversity may necessitate different properties of heterocysts. However, possible differences in heterocysts have largely remained unexplored due to the minority of heterocysts among major vegetative cells. Here, we have applied spectroscopic microscopy to Rivularia and A. variabilis to analyze their thylakoid membranes in individual cells. Absorption and fluorescence spectral imaging enabled us to estimate concentrations and interconnections of key photosynthetic components like photosystem I (PSI), photosystem II (PSII) and subunits of light-harvesting phycobilisome including phycocyanin (PC). The concentration of PC in heterocysts of Rivularia is far higher than that of A. variabilis. Fluorescence quantum yield of PC in Rivularia heterocysts was found to be virtually the same as those in its vegetative cells, while fluorescence quantum yield of PC in A. variabilis heterocysts was enhanced in comparison with its vegetative cells. PSI concentration in the thylakoid membranes of heterocysts seems to remain nearly the same as those of the vegetative cells in both the species. The average stoichiometric ratio between PSI monomer and PC hexamer in Rivularia heterocysts is estimated to be about 1:1.
巻・号 1858(9)
ページ 742-749
公開日 2017-9-1
DOI 10.1016/j.bbabio.2017.05.007
PII S0005-2728(17)30097-X
PMID 28576442
MeSH Absorption, Radiation Anabaena variabilis / metabolism Anabaena variabilis / radiation effects Anabaena variabilis / ultrastructure Cyanobacteria / metabolism Cyanobacteria / radiation effects Cyanobacteria / ultrastructure* Intracellular Membranes / ultrastructure Light Microscopy / methods* Microscopy, Fluorescence Nitrogen Fixation Photosystem I Protein Complex / metabolism Photosystem I Protein Complex / radiation effects Phycobilisomes / radiation effects Phycobilisomes / ultrastructure Phycocyanin / analysis Species Specificity Spectrum Analysis / methods Thylakoids / metabolism Thylakoids / radiation effects Thylakoids / ultrastructure*
IF 3.411
引用数 6
リソース情報
藻類 NIES-2095