Nitrogenase Activity in Heterocysts of Blue–Green Algae

Stewart, W. D. P.; Haystead, A.; Pearson, H. W.

doi:10.1038/224226a0

Cited by 185 publications

(76 citation statements)

References 16 publications

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“…Among the filamentous BGA, the ability to fix nitrogen under aerobic conditions is strictly correlated with the ability to form heterocyst (Stewart, 1969). In the present investigation, the heterocyst frequency ( fig.8) decreased at higher metal concentration.This could be either due to the inhibited synthesis of proteins involved in heterocyst differentiation or due to degradation of pre-existing heterocyst.…”

Section: Pbsupporting

confidence: 48%

Effect on Biochemical Parameters of Cyanobacterium Anabaena Sp Under Lead Stress.

Deep¹,

Bhattacharyya²,

Nayak³

2016

IJAR

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Section: Pbsupporting

confidence: 48%

Effect on Biochemical Parameters of Cyanobacterium Anabaena Sp Under Lead Stress.

Deep¹,

Bhattacharyya²,

Nayak³

2016

IJAR

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“…In the absence of a combined nitrogen source, a small fraction of the cells in the trichome develop into heterocysts, Cyan0 bacteria 7 distinguishable from vegetative cells by their thick walls, relatively weak pigmentation and refractile polar granules (Figs 43,44,49). When mature, the heterocyst can neither divide nor dedifferentiate; it is the specific cellular site of nitrogen fixation under aerobic conditions (Stewart et al, 1969). Polar granules form near the point(s) of attachment of the heterocyst to adjacent vegetative cells.…”

Section: Resultsmentioning

confidence: 99%

Generic Assignments, Strain Histories and Properties of Pure Cultures of Cyanobacteria

et al. 1979

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On the basis of a comparative study of 178 strains of cyanobacteria, representative of this group of prokaryotes, revised definitions of many genera are proposed. Revisions are designed to permit the generic identification of cultures, often difficult through use of the field-based system of phycological classification. The differential characters proposed are both constant and readily determinable in cultured material. The 22 genera recognized are placed in five sections, each distinguished by a particular pattern of structure and development. Generic descriptions are accompanied by strain histories, brief accounts of strain properties, and illustrations; one or more reference strains are proposed for each genus. The collection on which this analysis was based has been deposited in the American Type Culture Collection, where strains will be listed under the generic designations proposed here. I N T R O D U C T I O NThe cyanobacteria constitute one of the largest sub-groups of Gram-negative prokaryotes. As a result of their traditional assignment to the algae, the classification of these organisms was developed by phycologists, working under the provisions of the Botanical Code (Stafleu et al., 1972). Almost entirely on the basis of observations on field materials, about 150 genera and well over lo00 species have been described. The discriminatory properties, both generic and specific, are either structural or ecological, these being virtually the only characters determinable in the field. Types are represented by herbarium specimens or, failing these, by descriptions and illustrations; cultures are not recognized as valid type materials under the Botanical Code.The attempt to identify cyanobacteria in culture through this field-based system of classification leads to many difficulties and ambiguities. The limited and necessarily provisional taxonomic goal of the present article is to redefine certain cyanobacterial genera in such a way that simple and clear-cut generic assignments can be made for cultures. It is based on our experience over the past decade with pure strains representative of all major sub-groups of cyanobacteria. As far as possible, we have attempted to maintain the system of generic nomenclature and the generic definitions now used by phycologists (Bourrelly, 1970;Geitler, 1932;Desikachary, 1959). However, when the discriminatory characters that nominally distinguish two genera are either not determinable on cultures or within the range of variation of a single strain, the existing genera have been combined. Some of the proposed generic definitions include discriminatory characters that have not hitherto received taxo-

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“…Recently Stewart, Haystead & Pearson (1969) produced strong biochemical evidence indicating the location of nitrogen-fixing activity in heterocysts. High oxygen tension is known to inhibit nitrogenase activity (Fay & Cox, 1967) and we (Thomas, 1970; Thomas et al I 970) have demonstrated the absence in heterocysts of photosystem I1 of photosynthesis responsible for the evolution of molecular oxygen.…”

Section: Discussionmentioning

confidence: 99%

Studies on the Physiology of Heterocyst Production in the Nitrogen-fixing Blue-green Alga Anabaena sp. L-31 in Continuous Culture

Thomas

David

1971

Journal of General Microbiology

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SUMMARYInduction of heterocysts in the blue-green alga Anabaena sp. L-31 is totally inhibited by potassium nitrate in batch cultures whereas in continuous cultures no inhibition is observed at high dilution rates. When nitrate is utilized ammonia accumulates in the growth medium, the quantity of extracellular ammonia declining with increasing dilution rate.The rate of release of ammonia per cell increases with decreasing density of organisms, and induction of heterocysts is consistently observed when ammonia release per cell exceeds 2 x 1 0 -l~ pg. It is inferred that such excessive release depletes the level of intracellular ammonia causing the induction of heterocysts.

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Nitrogenase Activity in Heterocysts of Blue–Green Algae

Cited by 185 publications

References 16 publications

Effect on Biochemical Parameters of Cyanobacterium Anabaena Sp Under Lead Stress.

Effect on Biochemical Parameters of Cyanobacterium Anabaena Sp Under Lead Stress.

Generic Assignments, Strain Histories and Properties of Pure Cultures of Cyanobacteria

Studies on the Physiology of Heterocyst Production in the Nitrogen-fixing Blue-green Alga Anabaena sp. L-31 in Continuous Culture

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