Glycerol 3-phosphate inhibits swarming and aggregation of Myxococcus xanthus.
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ABSTRACT:
SUBMITTER: Moraleda-Munoz A
PROVIDER: S-EPMC99693 | biostudies-literature | 2001 Oct
REPOSITORIES: biostudies-literature
Publications
Glycerol 3-phosphate inhibits swarming and aggregation of Myxococcus xanthus.
Moraleda-Muñoz A A Carrero-Lérida J J Extremera A L AL Arias J M JM Muñoz-Dorado J J
Journal of bacteriology 20011001 20
We have cloned a gene of Myxococcus xanthus with similarities to the permease for glycerol 3-phosphate (G3P) of other bacteria. Expression of the gene increased significantly during the first hours of starvation. Swarming of the wild-type strain was inhibited and aggregation was delayed by G3P. Conversely, a DeltaglpT strain aggregated even on rich medium. These results indicate that G3P may function to regulate the timing of aggregation in M. xanthus. ...[more]
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Project description:Under starvation conditions, a swarm of Myxococcus xanthus cells will undergo development, a multicellular process culminating in the formation of many aggregates called fruiting bodies, each of which contains up to 100,000 spores. The mechanics of symmetry breaking and the self-organization of cells into fruiting bodies is an active area of research. Here we use microcinematography and automated image processing to quantify several transient features of developmental dynamics. An analysis of experimental data indicates that aggregation reaches its steady state in a highly nonmonotonic fashion. The number of aggregates rapidly peaks at a value 2- to 3-fold higher than the final value and then decreases before reaching a steady state. The time dependence of aggregate size is also nonmonotonic, but to a lesser extent: average aggregate size increases from the onset of aggregation to between 10 and 15 h and then gradually decreases thereafter. During this process, the distribution of aggregates transitions from a nearly random state early in development to a more ordered state later in development. A comparison of experimental results to a mathematical model based on the traffic jam hypothesis indicates that the model fails to reproduce these dynamic features of aggregation, even though it accurately describes its final outcome. The dynamic features of M. xanthus aggregation uncovered in this study impose severe constraints on its underlying mechanisms.
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Project description:Myxococcus xanthus is a gram negative rod-shaped delta proteobacterium that differentiates into environmentally resistant spores in response to starvation. Little is known about the sporulation mechanism in part because sporulation occurs in a subpopulation of cells undergoing a lenghtly complex multicellular developmental program. This developmental program requires a solid surface, motility, a minimum population density and a sophisticated network of inter and intra-cellular signals which direct some cells first to aggregate into multicellular fruiting bodies and then to sporulate exclusively within these fruiting bodies. However, it has previously been demonstrated that synchronous conversion of vegetative cells into myxospores can also be triggered in nutrient-rich liquid medium by addition of glycerol to 0.5 M. Here, we took advantage of the glycerol-induced sporulation process to gain information about the core M. xanthus sprorulation mechanism. We determined changes in the global gene expression at 0.5, 1, 2, and 4 hours after glycerol induction compared to vegetative cells (wild-type DK1622). The expression of nearly 1,500 genes was found to be significantly altered at least two-fold within four hours of glycerol-induced development. Most of the known core sporulation marker genes were up-regulated, whereas most genes required for proper aggregation and fruiting body formation were not significantly regulated. Keywords: Time course of glycerol-induced (0.5 M final conc.) development with 4 time points referenced to vegetative cells
2010-05-06 | GSE17912 | GEO
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