Synergism between morphogenetic mutants of Myxococcus xanthus

Hagen, David; Bretscher, Anthony; Kaiser, Dale

doi:10.1016/0012-1606(78)90079-9

Cited by 403 publications

(352 citation statements)

References 9 publications

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“…Aliquots (10 ml) of cell suspension (1610 7 c.f.u.) were spotted on the surface of a clone fruiting (CF) agar plate (Hagen et al, 1978). The plates were incubated at 28 uC for 2-7 days.…”

Section: Methodsmentioning

confidence: 99%

PhpA, a tyrosine phosphatase of Myxococcus xanthus, is involved in the production of exopolysaccharide

et al. 2012

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Protein-tyrosine phosphorylation plays a significant role in multiple cellular functions in bacteria. Bacterial tyrosine phosphatases catalyse the dephosphorylation of tyrosyl-phosphorylated proteins. Myxococcus xanthus PhpA shares homology with DNA polymerase and histidinol phosphatase family members. Recombinant His-tagged PhpA requires Mn 2+ or Co 2+ for phosphatase activity, and shows strict specificity for phosphorylated tyrosine residues. The k m values of PhpA for p-nitrophenyl phosphate (pNPP) and phosphotyrosine peptide, RRLIEDAEpYAARG, were 803 and 139 mM, respectively. The phosphatase activity of PhpA was inhibited by sodium orthovanadate with a k i of 33 mM. phpA gene expression was observed under both vegetative and developmental conditions, but peaked during late fruiting body formation. A phpA mutant exhibited an elevated level of tyrosine phosphorylation of a 79 kDa protein and cytoplasmic tyrosine kinase, BtkA. In M. xanthus, exopolysaccharide (EPS) is essential for cellcell adhesion and fruiting body formation. phpA mutant cells exhibited enhanced capacity for cellcell agglutination in agglutination buffer. Under starvation conditions, phpA mutation caused early aggregation and sporulation. The EPS production assay showed that the phpA mutant produced an increased amount of EPS in comparison with the wild-type. These results indicate that PhpA may negatively regulate the production of EPS in M. xanthus.

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“…Aliquots (10 ml) of cell suspension (1610 7 c.f.u.) were spotted on the surface of a clone fruiting (CF) agar plate (Hagen et al, 1978). The plates were incubated at 28 uC for 2-7 days.…”

Section: Methodsmentioning

confidence: 99%

PhpA, a tyrosine phosphatase of Myxococcus xanthus, is involved in the production of exopolysaccharide

et al. 2012

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“…The developmentally proficient parent strain, M. xanthus DK1622 (13), and developmental mutant strains DK3260 and DK3261 (dsg) (2,15), DK5057 (asg) (9), and M380 (bsg) (8) were supplied by the laboratory of D. Kaiser. The csg mutant strain (DK2653) was supplied by L. Shimkets (28).…”

Section: Methodsmentioning

confidence: 99%

Role of autocide AMI in development of Myxococcus xanthus

Rosenbluh

Rosenberg

1990

J Bacteriol

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A new developmental mutant of Myxococcus xanthus has been isolated by screening TnV insertion mutants for AMI-dependent development in submerged culture. This mutant (ER304) aggregated and sporulated on agar surfaces but required at least 3.8 ,ug of autocide AMI per ml for development in submerged cultures. Spore rescue of ER304 was obtained with the saturated, monounsaturated, and diunsaturated fatty acid fractions of AMI, with specific activities of 68, 115, and 700 U/mg, respectively. In addition, several model fatty acids were capable of rescuing sporulation of ER304; however, there was no correlation between specific lytic activity observed in vegetative cultures and specific rescue activity. Rescue of ER304 was effected during the first ca. 12 h after the initiation of starvation conditions; after this time, addition of AMI or model fatty acids killed the cells. Supernatant fluids of ER304 rescued development in dsg mutants (e.g., DK3260) in submerged cultures, but dsg mutant supernatant fluids were incapable of rescuing ER304 development. The data presented in this article support the idea that the primary mechanism of rescue by AMI is not via lysis, although developmental lysis may be an indirect result of the rescue event. A membrane permeability model is presented to explain the role of autocides in early developmental events in wild-type strains and in the aggregation and sporulation rescue of developmental mutants ER304 and DK3260.Myxococcus xanthus, the most extensively studied member of the Myxobacterales, is a gram-negative, gliding bacterium, characterized by a complex, multicellular development program (33). Development of M. xanthus, which culminates in the building of spore-filled fruiting bodies, is contingent upon the fulfillment of several conditions: (i) a minimal cell density, (ii) a solid substratum to support the aggregating cells, and (iii) nutritional downshift of exponentially growing cells (25). Successful completion of the developmental process depends upon the proper functioning of many genes. Some of these genes are directly involved in the intercellular signaling necessary for coordinating specific multicellular activities (16); others affect development by controlling the motility (11, 12) or cohesiveness (27) of the cells.Autocides are substances produced by vegetative M. xanthus cells which are capable of inducing lysis in the producing and related strains (29). The two major autocides, referred to as AMI and AMV, have been isolated and chemically characterized (6, 30). Autocide AMV is phosphatidylethanolamine (PE), the major component of the inner and outer cell membranes of M. xanthus. Autocide AMI, a mixture of saturated, monounsaturated, and polyunsaturated fatty acids, appears to be an enzymatic breakdown product of AMV and its active lytic moiety. In addition to its autolytic activity, autocide AMI has recently been shown to be capable of accelerating aggregation and sporulation in the wild-type strain and of rescuing aggregation and sporulation in dsg development mutan...

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“…Vegetative cultures were grown in casitone/yeast extract (CYE) medium (14). Development was induced on clone fruiting (CF) agar (15). Plates were allowed to dry at room temperature for [10][11][12][13][14] 10 ,l per spot).…”

Section: Methodsmentioning

confidence: 99%

Myxobacterial hemagglutinin: A development-specific lectin of Myxococcus xanthus

Cumsky¹,

Zusman²

1979

Proc. Natl. Acad. Sci. U.S.A.

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Fruiting body formation in the bacterium Myxococcus znthus consists of a temporal sequence of cellular aggregation and sporulation. During the period of cellular aggregation, a major new development-specific protein that has lectin-like activity is synthesized. This protein, called myxobacterial hemagglutinin (MBHA), was able to agglutinate sheep or guinea pig erythrocytes but not horse, ox, chicken, or human erythrocytes. MBHA was undetectable in extracts of vegetative cells, cells starved in liquid buffer, or in glycerol-induced cells. However, cells starved on a fruiting medium produced large amounts of MBHA (about 5% of protein synthesis), starting at about 6-8 hr of development. The protein accumulated in the soluble fraction of cells, reaching a peak of 1-2% of total protein at about the time when aggregation was completed. At later times the amount of MBHA present in the soluble fraction declined although synthesis continued. The hemagglutinating activity of MBHA could not be inhibited with simple sugars or aminosugars but could be inhibited with fetuin, a fetal calf serum glycoprotein. The Oglycosidically linked trisaccharide glycopeptide of fetuin was shown to be inhibitory by itself. The penultimate galactose of this glycopeptide was directly implicated in the inhibitory activity, because the inhibition byasialofetuin was reduced to 1/60th by periodate oxidation and to 1/15th after -galactosidase treatment. MBHA is an abundant biochemical marker of development in M. Xanthus. Ihe fact that it is a lectin suggests that it may play a role in cell-cell recognition or agglutination.Myxococcus xanthus is a Gram-negative bacterium which, because of its complex life cycle, is well suited for studies of development. When nutrients are depleted in a solid culture medium, cells reverse their outward movement and glide inward towards aggregation centers, forming mounds consisting of about 106 to 107 cells. The flat mounds then tighten into raised translucent structures. Within the mounds, the rodshaped cells convert to round or ovoid spores, which are resting cells resistant to many environmental factors. Mounds of mature myxospores are referred to as fruiting bodies. Thus, M. zanthus is an attractive microbial system for the study of cell-cell interactions during the aggregation process as well as cellular morphogenesis during sporulation.Cell surface carbohydrate binding or "lectin-like" proteins have been implicated in cell-cell interactions and intercellular adhesion in the cellular slime molds Dictyostelhum discoldeum (1) and Polysphondylium pallidum (2) as well as in other eukaryotic systems (3, 4). These proteins may act as molecular hooks directly facilitating cell-cell contact and recognition at the appropriate times during development or tissue differentiation (5-8). Lectins have been found in nondifferentiating cells as well (9-12). We therefore examined extracts of M. xanthus for a hemagglutinating activity. In this paper, we report that during fruiting body formation a major new development-s...

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Synergism between morphogenetic mutants of Myxococcus xanthus

Cited by 403 publications

References 9 publications

PhpA, a tyrosine phosphatase of Myxococcus xanthus, is involved in the production of exopolysaccharide

PhpA, a tyrosine phosphatase of Myxococcus xanthus, is involved in the production of exopolysaccharide

Role of autocide AMI in development of Myxococcus xanthus

Myxobacterial hemagglutinin: A development-specific lectin of Myxococcus xanthus

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