caa a22 4500 475746937 CHVBK 20180406123516.0 cr unu---uuuuu 170329e20001101xx s 000 0 eng 10.1007/s002840010151 doi (NATIONALLICENCE)springer-10.1007/s002840010151 Calcium and Phosphate Regulation of Nitrogen Metabolism in the Cyanobacterium Spirulina platensis Under the High Light Stress [Elektronische Daten] [D.P. Singh, Namita Singh] High light stress (40 W/m2)-induced alterations in the nitrogen assimilatory enzymes in Spirulina platensis were studied under the Ca2+ and phosphate (Pi)-supplemented as well as starved conditions. Results revealed that activities of nitrate reductase (NR), amino acid transferases (AST/GOT and ALT/GPT), and protease enzymes in the high-light-incubated cells were relatively higher under the Ca2+- and Pi-starved conditions. On the contrary, relative rates of glutamine synthetase (GS) and ATPase activities were lower in the Ca2+- and Pi-starved cells. But the Spirulina cells under the Ca2+- and Pi-added conditions showed enhanced activity of both GS and ATPase enzymes. During the high-light stress, a decline in the GS activity, particularly under the Ca2+- and Pi-starved conditions, was indicative of a nitrogen starvation-like condition. This could be one of the reasons for induction of the NR and protease enzymes. A higher rate of GS activity was recorded under both the Ca2+- and Pi-supplemented conditions, perhaps owing to the enhanced rate of ATPase activity in such conditions. But a declining pattern of both NR and protease activities in the presence of Ca2+ and Pi, despite the higher rate of ATPase activity, might involve some other mechanism like the protein-kinase system. Springer-Verlag New York Inc., 2000 Singh D.P. School of Environmental Sciences, B.B.Ambedkar University, Lucknow-226025, India, IN aut Singh Namita Institute of Microbiology and Biotechnology, Barkatullah University, Bhopal-462026, India, IN aut https://doi.org/10.1007/s002840010151 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002840010151 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Singh D.P. School of Environmental Sciences, B.B.Ambedkar University, Lucknow-226025, India, IN aut NATIONALLICENCE 700 1- Singh Namita Institute of Microbiology and Biotechnology, Barkatullah University, Bhopal-462026, India, IN aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer