1. Microcystin Biosynthesis and mcyA Expression in Geographically Distinct Microcystis Strains under Different Nitrogen, Phosphorus, and Boron Regimes.
- Author
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Srivastava, Ankita, Ko, So-Ra, Ahn, Chi-Yong, Oh, Hee-Mock, Ravi, Alok Kumar, and Asthana, Ravi Kumar
- Subjects
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BACTERIAL metabolism , *AGAR , *ANALYSIS of variance , *BACTERIAL physiology , *BACTERIAL toxins , *CELL division , *CELLULAR signal transduction , *ELECTROPHORESIS , *GENE expression , *MICROBIAL genetics , *MICROBIOLOGICAL techniques , *MULTIVARIATE analysis , *NITROGEN , *NUTRITIONAL requirements , *PEPTIDES , *PHOSPHORUS , *POLYMERASE chain reaction , *RESEARCH funding , *TRACE elements , *AQUATIC microbiology , *REVERSE transcriptase polymerase chain reaction , *DATA analysis software , *SEQUENCE analysis , *PHYSIOLOGY - Abstract
Roles of nutrients and other environmental variables in development of cyanobacterial bloom and its toxicity are complex and not well understood. We have monitored the photoautotrophic growth, total microcystin concentration, and microcystins synthetase gene (mcyA) expression in lab-grown strains of Microcystis NIES 843 (reference strain), KW (Wangsong Reservoir, South Korea), and Durgakund (Varanasi, India) under different nutrient regimes (nitrogen, phosphorus, and boron). Higher level of nitrogen and boron resulted in increased growth (avg. 5 and 6.5 Chl a mg/L, resp.), total microcystin concentrations (avg. 1.185 and 7.153 mg/L, resp.), and mcyA transcript but its expression was not directly correlated with total microcystin concentrations in the target strains. Interestingly, Durgakund strain had much lower microcystin content and lacked microcystin-YR variant over NIES 843 and KW. It is inferred that microcystin concentration and its variants are strain specific. We have also examined the heterotrophic bacteria associated with cyanobacterial bloom in Durgakund Pond and Wangsong Reservoir which were found to be enriched in Alpha-, Beta-, and Gammaproteobacteria and that could influence the bloom dynamics. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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