Morphogenesis of Cysts in
            <i>Azotobacter vinelandii</i>

Hitchins, Victoria M.; Sadoff, H. L.

doi:10.1128/jb.104.1.492-498.1970

Cited by 39 publications

(23 citation statements)

References 20 publications

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“…In the cytoplasm, vesicles containing polyhydroxybutyrate as a carbon and energy reserve accumulate, and on the outside of the cells a deposition of coat material eventually leads to an encasement of the cell, by formation of a layer designated the exine. In the space between the exine and the cell wall a viscous material, the intine, develops (Wyss et al, 1961;Hitchins and Sadoff, 1970). The exine is characterized by being structured and rigid with alginates rich in GG block sequences.…”

Section: Introductionmentioning

confidence: 99%

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The Azotobacter vinelandii AlgE mannuronan C‐5‐epimerase family is essential for the in vivo control of alginate monomer composition and for functional cyst formation

Steigedal

Sletta

Moreno

et al. 2008

Environmental Microbiology

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The industrially widely used polysaccharide alginate is a co-polymer of beta-D-mannuronic acid and alpha-L-guluronic acid (G), and the G residues originate from a polymer-level epimerization process catalysed by mannuronan C-5-epimerases. In the genome of the alginate-producing bacterium Azotobacter vinelandii genes encoding one periplasmic (AlgG) and seven secreted such epimerases (AlgE1-7) have been identified. Here we report the generation of a strain (MS163171) in which all the algE genes were inactivated by deletion (algE1-4 and algE6-7) or interruption (algE5). Shake flask-grown MS163171 produced a polymer containing less than 2% G (algG still active), while wild-type alginates contained 25% G. Interestingly, addition of proteases to the MS163171 growth medium resulted in a strong increase in the chain lengths of the alginates produced. MS163171 was found to be unable to form functional cysts, which is a desiccation-resistant differentiated form developed by A. vinelandii under certain environmental conditions. We also generated mutants carrying interruptions in each separate algE gene, and a strain containing algE5 only. Studies of these mutants indicated that single algE gene inactivations, with the exception of algE3, did not affect the fractional G content much. However, for all strains tested the alginate composition varied somewhat as a response to the growth conditions.

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Section: Introductionmentioning

confidence: 99%

“…The intine, in contrast, is less structured and its alginates consist mostly of MG and MM blocks (Page and Sadoff, 1975). When the environment is again suitable for growth, A. vinelandii escapes dormancy and re-enters the vegetative state (Wyss et al, 1961;Hitchins and Sadoff, 1970).…”

Section: Introductionmentioning

confidence: 99%

The Azotobacter vinelandii AlgE mannuronan C‐5‐epimerase family is essential for the in vivo control of alginate monomer composition and for functional cyst formation

Steigedal

Sletta

Moreno

et al. 2008

Environmental Microbiology

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“…Cytologically, encystment is initiated by the rounding up of the rod-shaped vegetative cell, its loss of motility Hitchins and Sadoff, 1970) and the termination of cell division (Sadoff et al, 1971). A loose-®tting, non-structured material develops around the cell, and the cytoplasmic content of vesicles containing an intracellular carbon and energy reserve, poly b-hydroxybutyrate (PHB), increases.…”

Section: Introductionmentioning

confidence: 99%

“…Upon germination of the cyst the central body enlarges again, eventually leading to its release from the ruptured, horseshoe-formed exine. The released central body then develops into a vegetative rod Hitchins and Sadoff, 1970).…”

Section: Introductionmentioning

confidence: 99%

Mannuronan C‐5 epimerases and cellular differentiation of Azotobacter vinelandii

Høidal

Svanem

Gimmestad

et al. 2000

Environmental Microbiology

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Differentiation in Azotobacter vinelandii involves the encystment of the vegetative cell under adverse environmental circumstances and the germination of the resting cell into the vegetative state when growth conditions are satisfactory again. Morphologically, the encystment process involves the development of a protective coat around the resting cell. This coat partly consists of multiple layers of alginate, which is a copolymer of beta-D-mannuronic acid (M) and alpha-L-guluronic acid (G). Alginate contributes to coat rigidity by virtue of a high content of GG blocks. Such block structures are generated through a family of mannuronan C-5 epimerases that convert M to G after polymerization. Results from immunodetection and light microscopy, using stains that distinguish between different cyst components and types, indicate a correlation between cyst coat organization and the amount and appearance of mannuronan C-5 epimerases in the extracellular medium and attached to the cells. Specific roles of individual members of the epimerase family are indicated. Calcium and magnesium ions appear to have different roles in the structural organization of the cyst coat. Also reported is a new gene sharing strong sequence homology with parts of the epimerase-encoded R-modules. This gene is located within the epimerase gene cluster of Azotobacter vinelandii.

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“…by electron microscopy [5] have been investigated during differentiation from vegetative cell to cyst. These have revealed a number of important differences (see [6] for review).…”

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confidence: 99%

Respiratory properties of cysts and vegetative cells of Azotobacter vinelandii

Field¹

1983

FEMS Microbiology Letters

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The respiratory activity of cysts of Azotobacter vinelandii has been compared with that of vegetative cells. Whole cysts had a much reduced respiratory activity which was less sensitive to KCN. Substrate oxidation rates by membrane preparations from cysts were reduced approximately 10fold and sensitivity to KCN was decreased by a similar factor. Difference spectra of cyst membranes revealed changes in cytochrome content. Cytochrome oxidase d was apparently absent, cytochrome a~ levels were approximately halved whilst those of cytochrome oxidase o were almost doubled. Cytochromes of the b and c-type were present in similar amounts to those in vegetative cells.

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Morphogenesis of Cysts in Azotobacter vinelandii

Cited by 39 publications

References 20 publications

The Azotobacter vinelandii AlgE mannuronan C‐5‐epimerase family is essential for the in vivo control of alginate monomer composition and for functional cyst formation

The Azotobacter vinelandii AlgE mannuronan C‐5‐epimerase family is essential for the in vivo control of alginate monomer composition and for functional cyst formation

Mannuronan C‐5 epimerases and cellular differentiation of Azotobacter vinelandii

Respiratory properties of cysts and vegetative cells of Azotobacter vinelandii

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