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Nitrogen stress induced changes in the marine cyanobacterium Oscillatoria willei BDU 130511.

Authors
  • Kumar Saha, Sushanta
  • Uma, Lakshmanan
  • Subramanian, Gopalakrishnan
Type
Published Article
Journal
FEMS Microbiology Ecology
Publisher
Oxford University Press
Publication Date
Aug 01, 2003
Volume
45
Issue
3
Pages
263–272
Identifiers
DOI: 10.1016/S0168-6496(03)00162-4
PMID: 19719595
Source
Medline
License
Unknown

Abstract

Exclusion of combined nitrogen (NaNO3) from the growth medium caused certain changes in metabolic processes leading to cessation in growth of the non-heterocystous, non nitrogen-fixing marine cyanobacterium Oscillatoria willei BDU 130511. But antioxidative enzymes, namely superoxide dismutase and peroxidase, helped the organism to survive the nitrogen stress. Prominent effects observed during nitrogen starvation/limitation were: (i) reduction of major and accessory photosynthetic pigments, (ii) impairment of photosynthesis due to loss of one major Rubisco isoenzyme, (iii) reduced synthesis of lipids and fatty acids, (iv) modifications of protein synthesis leading to the repression of three polypeptides and synthesis of two new polypeptides, (v) enhanced glutamine synthetase and reduced nitrate reductase activities, (vi) enhanced production of hydrogen peroxide and (vii) induced appearance of four new peroxidase isoenzymes. The observed metabolic changes were reversible, and the arrested growth under prolonged nitrogen deficiency could be fully restored upon subculturing in freshly prepared ASN III medium containing nitrogen (NaNO3). The present study demonstrates the capability of a non-nitrogen-fixer to withstand nitrogen stress making it an ecologically successful organism in the marine environment. The above pleiotropic effects of nitrogen deficiency also demonstrate that nitrogen plays a crucial role in growth and metabolism of marine cyanobacteria.

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