Yoshitaka Nishiyama

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Light stress and salt stress are major environmental factors that limit the efficiency of photosynthesis. However, we have found that the effects of light and salt stress on photosystem II (PSII) in the cyanobacterium Synechocystis sp. PCC 6803 are completely different. Strong light induced photodamage to PSII, whereas salt stress inhibited the repair of(More)
When photosynthetic organisms are exposed to abiotic stress, their photosynthetic activity is significantly depressed. In particular, photosystem II (PSII) in the photosynthetic machinery is readily inactivated under strong light and this phenomenon is referred to as photoinhibition of PSII. Other types of abiotic stress act synergistically with light(More)
The Amphibacillus xylanus NADH oxidase, which catalyzes the reduction of oxygen to hydrogen peroxide with beta-NADH, can also reduce hydrogen peroxide to water in the presence of free flavin adenine dinucleotide (FAD) or the small disulfide-containing Salmonella enterica AhpC protein. The enzyme has two disulfide bonds, Cys128-Cys131 and Cys337-Cys340,(More)
We have characterized four putative ADP-ribose pyrophosphatases Sll1054, Slr0920, Slr1134, and Slr1690 in the cyanobacterium Synechocystis sp. strain PCC 6803. Each of the recombinant proteins was overexpressed in Escherichia coli and purified. Sll1054 and Slr0920 hydrolyzed ADP-ribose specifically, while Slr1134 hydrolyzed not only ADP-ribose but also NADH(More)
The repair of photosystem II (PSII) after photodamage is particularly sensitive to reactive oxygen species—such as H2O2, which is abundantly produced during the photoinhibition of PSII. In the present study, we generated a transformant of the cyanobacterium Synechococcus elongatus PCC 7942 that expressed a highly active catalase, VktA, which is derived from(More)
We present a polymer-enhanced capillary transient isotachophoresis (PectI) selection methodology for acquisition of high-affinity (kinetically inert) DNA aptamers capable of recognizing distinct microbial cell surfaces, which requires only a single electrophoretic separation between particles (free cells and cells bound with aptamers) and molecules (unbound(More)
The cyAbrB2 transcriptional regulator is essential for active sugar catabolism in Synechocystis sp. PCC 6803 grown under light conditions. In the light-grown cyabrB2-disrupted mutant, glycogen granules and sugar phosphates corresponding to early steps in the glycolytic pathway accumulated to higher levels than those in the wild-type (WT) strain, whereas the(More)
LexA is a well-established transcriptional repressor of SOS genes induced by DNA damage in Escherichia coli and other bacterial species. However, LexA in the cyanobacterium Synechocystis sp. PCC 6803 has been suggested not to be involved in SOS response. In this study, we performed RNA-seq analysis of the wild-type strain and the lexA-disrupted mutant to(More)
In response to an increased level of Zn(2+), Synechococcus sp. PCC 7942 expresses SmtA, a metallothionein-like metal-chelating protein, while Synechocystis sp. PCC 6803 expresses ZiaA, a transporter of Zn(2+). The gene expression of these proteins is regulated by repressor protein, SmtB and ZiaR, respectively. In spite of contributing to different response(More)