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Title: Analysis of carbohydrate storage granules in the diazotrophic cyanobacterium Cyanothece sp. PCC 7822

The unicellular diazotrophic cyanobacteria of the genus Cyanothece demonstrate oscillations in nitrogenase activity and H 2 production when grown under 12h light-12h dark cycles. We established that Cyanothece sp. PCC 7822 allows for the construction of knock-out mutants and our objective was to improve the growth characteristics of this strain and to identify the nature of the intracellular storage granules. We report the physiological and morphological effects of reduction in nitrate and phosphate concentrations in BG-11 media on this strain. We developed a series of BG-11-derived growth media and monitored batch culture growth, nitrogenase activity and nitrogenase-mediated hydrogen production, culture synchronicity, and intracellular storage content. Reduction in NaNO3 and K 2HPO 4 concentrations from 17.6 and 0.23 mM to 4.41 and 0.06 mM, respectively, improved growth characteristics such as cell size and uniformity, and enhanced the rate of cell division. Cells grown in this low NP BG-11 were less complex, a parameter that related to the composition of the intracellular storage granules. Cells grown in low NP BG-11 had less polyphosphate, fewer polyhydroxybutyrate granules and many smaller granules became evident. Biochemical analysis and transmission electron microscopy using the histocytochemical PATO technique demonstrated that these small granules contained glycogen. The glycogenmore » levels and the number of granules per cell correlated nicely with a 2.3 to 3.3-fold change from the minimum at L0 to the maximum at D0. The differences in granule morphology and enzymes between Cyanothece ATCC 51142 and Cyanothece PCC 7822 provide insights into the formation of large starch-like granules in some cyanobacteria.« less
 [1] ;  [1] ;  [2] ;  [2] ;  [1]
  1. Purdue Univ., West Lafayette, IN (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0166-8595; 47732; 44624; KP1704020
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Photosynthesis Research; Journal Volume: 118; Journal Issue: 1
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org:
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; PHOTOSYNTHESIS; CARBOHYDRATES; GLYCOGEN; Photosynthesis; carbohydrate; diazotrophic; cyanobacterium; Cyanothece; cells; glycogen; Environmental Molecular Sciences Laboratory