Encystment and germination in Azotobacter vinelandii.

Sadoff, H L

doi:10.1128/mmbr.39.4.516-539.1975

Cited by 121 publications

(71 citation statements)

References 121 publications

(173 reference statements)

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“…The molecular mass calibration curve is missing for molecules eluting below 12 ml (entire MS163171 sample) due to inconsistent values for samples with a molecular mass over 10 6 Da. 1968; Sadoff, 1975). The difference between the wild type and MS163171 was also very obvious upon inspection of the cells in a transmission electron microscope ( Fig.…”

Section: Fig 3 Molecular Mass Distribution Of Alginates From a Vinmentioning

confidence: 92%

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: Fig 3 Molecular Mass Distribution Of Alginates From a Vinmentioning

confidence: 92%

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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“…It Is also worth noting that Azotobacter vinelandii another bacterium producing alginate. does so as a part of the developmental process of encystment (Sadoff. 1975).…”

Section: Strain"mentioning

confidence: 99%

Differentiation of Pseudomonas aeruginosa into the alginate‐producing form: inactivation of mucB causes conversion to mucoidy

Martin

Schurr

Mudd

et al. 1993

Molecular Microbiology

113

153

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Mucoidy in Pseudomonas aeruginosa is a critical virulence factor associated with chronic respiratory infections in cystic fibrosis. A cluster of three tightly linked genes, algU, mucA and mucB located at 67.5 min, controls development of mucoid phenotype. This locus is allelic with a group of mutations (muc) associated with conversion into constitutively mucoid forms. One of the genes previously characterized in this region, algU, is absolutely required for the transcriptional activation of algD, a critical event in the establishment of mucoidy. AlgU is homologous to the alternative sigma factor sigma H (Spo0H) controlling sporulation and competence in Bacillus. Two genes downstream of algU, mucA and mucB were further characterized in this study. Previous complementation studies have demonstrated that mucA is required for suppression of mucoidy in the muc-2 strain PAO568. In this work, complementation analysis indicated that, in addition, mucB was required for suppression of mucoidy in the muc-25 strain PAO581, and for enhanced complementation of the muc-2 mutation in PAO568. The complete nucleotide sequence of mucA and mucB was determined. Insertional inactivation of mucB on the chromosome of the standard genetic strain PAO resulted in mucoid phenotype, and in a strong transcriptional activation of algD. Thus, a loss of mucB function is sufficient to cause conversion of P. aeruginosa into the mucoid phenotype. Since the algU-mucA-mucB region is a general site where muc mutations have been mapped, it is likely that mucB participates in the emergence of mucoid forms. Both mucA and mucB play a regulatory role in concert with the sigma-like factor AlgU; all three genes, along with signal transduction and histone-like elements, control differentiation of P. aeruginosa into the mucoid phenotype.

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“…Their role is more likely to be in differentiation and encystment where very great changes occur in the surface polymers of the bacteria [115]. It has been reported that alginate with differing composition is present in various locations inside and outside the Azotobacter cysts [106]. However, no apparent change in enzyme specificity was noted following encystment; the greatest activity remained against alginates of high mannuronate content.…”

Section: Possible Role Of Lyases In Development Of Azotobacter Spp ?mentioning

confidence: 99%

Polysaccharide lyases

Sutherland

1995

FEMS Microbiology Reviews

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Polysaccharide lyases are the products of various microorganisms, bacteriophage and some eukaryotes. All such enzymes cleave a hexose-1,4-alpha- or beta-uronic acid sequence by beta-elimination. They are in some examples, the only known type of enzymes degrading their polyanionic substrates. Although only a small number of these enzymes have been exhaustively studied, the pectin lyases of bacterial origin have proved to be of interesting crystal structure containing a parallel beta-helix domain. Alginate and heparin lyases may yield products with biotechnological potential.

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Encystment and germination in Azotobacter vinelandii.

Cited by 121 publications

References 121 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

Differentiation of Pseudomonas aeruginosa into the alginate‐producing form: inactivation of mucB causes conversion to mucoidy

Polysaccharide lyases

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