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The coexistence of competing species is a long-lasting puzzle in evolutionary ecology research. Despite abundant experimental evidence showing that the opportunity for coexistence decreases as niche overlap increases between species, bacterial species and strains competing for the same resources are commonly found across diverse spatially heterogeneous habitats. We thus hypothesized that the spatial scale of competition may play a key role in determining bacterial coexistence, and interact with other mechanisms that promote coexistence, including a growth-motility tradeoff. To test this hypothesis, we let two Pseudomonas putida strains compete at local and regional scales by inoculating them either in a mixed droplet or in separate droplets in the same Petri dish, respectively. We also created conditions that allow the bacterial strains to disperse across abiotic or fungal hyphae networks. We found that competition at the local scale led to competitive exclusion while regional competition promoted coexistence. When competing in the presence of dispersal networks, the growth-motility tradeoff promoted coexistence only when the strains were inoculated in separate droplets. Our results provide a mechanism by which existing laboratory data suggesting competitive exclusion at a local scale is reconciled with the widespread coexistence of competing bacterial strains in complex natural environments with dispersal.

A novel endospore forming bacterium designated strain GSsed3T was isolated from deposits clogging aboveground filters from the geothermal power plant of Gross Schoenebeck in Northern Germany. The novel isolate was Gram staining positive facultative anaerobe catalase positive and oxidase positive. Optimum growth occurred at 60 °C 0.5 (w/v) NaCl and pH 7 8. Analysis of the 16S rRNA sequence similarity indicated that strain GSsed3T belongs to the genus Anoxybacillus and showed 99.8 sequence similarity to Anoxybacillus rupiensis R270T 98.2 similarity to Anoxybacillus tepidamans GS5 97T 97.9 similarity to Anoxybacillus voinovskiensis TH13T 97.7 similarity to Anoxybacillus caldiproteolyticus DSM 15730T and 97.6 similarity to Anoxybacillus amylolyticus MR3CT. DNA DNA hybridization (DDH) indicated only 16 relatedness to A. rupiensis DSM 17127T. Furthermore DDH estimation based on genomes analysis indicated only 19.9 overall nucleotide similarity to A. amylolyticus DSM 15939T. The major respiratory menaquinone was MK 8. The polar lipid profile consisted of phosphatidylethanolamine phosphatidylglycerol diphosphatidylglycerol one unknown phosphoglycolipid and one unknown phospholipid. The predominant cellular fatty acids were iso C15:0 iso C17:0 C16:0 iso C16:0 and anteiso C17:0. The peptidoglycan type was A1? meso Dpm direct. The genomic DNA G+C content of the strain was 46.9 mol. The phenotypic genotypic and chemotaxonomic characterization indicated that strain GSsed3T differs from related species of the genus. Therefore strain GSsed3T is considered to be a novel species of the genus Anoxybacillus for which the name Anoxybacillus geothermalis sp. nov. is proposed. The type strain of Anoxybacillus geothermalis is GSsed3T ( = CCOS808T = ATCC BAA2555T).

Characterization of the action of the molecular chaperone PceT on the reductive dehalogenase PceA

Action of Molecular Chaperones dedicated to the maturation of Reductive Dehalogenases