title: Ultrastructural stability under high temperature or intensive light stress conferred by a small heat shock protein in cyanobacteria.
abstract: The role and sub-cellular localization of the small heat shock protein HspA under stress conditions was investigated comparing the cyanobacterium Synechococcus strain ECT16-1, which constitutively expresses HspA, with the reference strain ECT. The ultrastructure of ECT cells under elevated temperature or intensive light stress exhibited severe damage including aggregation of cytosol and disordered thylakoid membranes, but in ECT16-1 cells these ultrastructural changes were much less conspicuous. Immunocytochemical studies showed that the main localization of HspA in the ECT16-1 cells shifted from the thylakoid area to the cytoplasm, then back to thylakoid area during the heat stress. Expression of HspA stabilized the morphology of nucleoids. The results are discussed, in particular with respect to the unique property of HspA to associate with thylakoid membranes.
authors.affiliation: Department of Regulation-Biology, Saitama University, Saitama 338-8570, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Nitta
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Suzuki
authors.forename: Daisuke
authors.initials: D
authors.lastname: Honma
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakamoto
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D000458:Cyanobacteria / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure*; D004269:DNA, Bacterial / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D007150:Immunohistochemistry; D007211:Indoles; D008027:Light; D008854:Microscopy, Electron; D011489:Protein Denaturation / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006360:Heat-Shock Proteins; C113725:HspA protein, bacteria; D007211:Indoles; C007293:DAPI