Pseudomonas prosekii isolated in Antarctica inhibits plantpathogenic strains of Pseudomonas viridiflava and Pseudomonas fluorescens

Pseudomonas-caused plant diseases are present worldwide and affect most of the major lineages of higher plants which, as a consequence, may result in significant economic losses. Despite the use of bacteriocins produced by rhizosphere and soil bacteria has been nowadays considered as novel crop protection approach, antagonistic interactions of cold-adapted isolates toward agriculturally important phytopathogenic bacteria have not been studied yet. In this study, we tested inhibition activity of Antarctic Pseudomonas spp. against phytopathogenic pseudomonads. Four Antarctic stains (P. prosekii CCM 8878, CCM 8879, and CCM 8881 and Pseudomonas sp. CCM 8880) inhibited several phytopathogenic strains of P. viridiflava and P. fluorescens. Based on inhibition zone character and previous genome research we suggest that L-pyocin activity was responsible for this effect against P. viridiflava strains and that tailocin inhibited P. fluorescens isolate

First evidence of high-molecular-weight bacteriocin (tailocin) produced by Antarctic Pseudomonas spp.

Cold-adapted soil ecosystems represent dynamic communities varying in a structure, microbial abundance and metabolic activity. To antagonize competitors, soil bacteria produce a variety of inhibitory agents. We tested production of antimicrobials in Pseudomonas spp. isolated in James Ross Island, Antarctica, and performed transmission electron microscopic analyses of selected high-molecular-weight bacteriocin particles. The dimensions of R-tailocins produced by Pseudomonas sp. P2422 were 168 ± 2.0nm (length) and 16 ± 0.8nm (width) thus representing one of the largest tailocins secreted by Pseudomonas spp. To our knowledge, this is the first evidence of tailocin production by bacteria originated from polar regions

Free-Living Enterobacterium Pragia fontium 24613: Complete Genome Sequence and Metabolic Profiling

Pragia fontium is one of the few species that belongs to the group of atypical hydrogen sulfide-producing enterobacteria. Unlike other members of this closely related group, P. fontium is not associated with any known host and has been reported as a free-living bacterium. Whole genome sequencing and metabolic fingerprinting confirmed the phylogenetic position of P. fontium inside the group of atypical H2S producers. Genomic data have revealed that P. fontium 24613 has limited pathogenic potential, although there are signs of genome decay. Although the lack of specific virulence factors and no association with a host species suggest a free-living style, the signs of genome decay suggest a process of adaptation to an as-yet-unknown host

Genome sequences of two Antarctic strains of Pseudomonas prosekii: insights into adaptation to extreme conditions

Pseudomonas is ubiquitous bacterial genus with the high biotechnological potential. Pseudomonas prosekii is species recently described from James Ross Island (Antarctica). Although its endemic lifestyle could be assumed, its low-temperature adaptation mechanisms have not yet been described and understood. Therefore, we sequenced two P. prosekii strains and performed deep genome analysis with a special respect to the genes related to cold adaptation. We identified and analyzed the genes responsible for cold shock and oxidative stress response, osmoregulation, exopolysaccharide and siderophores production, and biofilm formation. Comparative genome analysis of P. prosekii and P. aeruginosa PAO1 highlighted differences in genome content between extremophile species and a mesophilic opportunistic pathogen

Description of Pseudomonas gregormendelii sp. nov., a novel psychrotrophic bacterium from James Ross Island, Antarctica

During the microbiological research performed within the scope of activities of Czech expeditions based at the Johann Gregor Mendel Station at James Ross Island, Antarctica, two psychrotrophic gram-stain negative non-fluorescent strains CCM 8506T and CCM 8507 from soil were extensively characterized using genotypic and phenotypic methods. Initial characterization using ribotyping with HindIII restriction endonuclease and phenotyping implies that both isolates belong to a single Pseudomonas species. Sequencing of rrs, rpoB, rpoD and glnA genes of strain CCM 8506(T) confirmed affiliation of investigated strains within the genus Pseudomonas. Further investigation using automated ribotyping with EcoRI (RiboPrinter(A (R)) Microbial Characterisation System), whole-cell protein profiling using the Agilent 2100 Bioanalyzer system, extensive biochemical testing and DNA-DNA hybridization experiments confirmed that both investigated strains are members of a single taxon which is clearly separated from all hitherto described Pseudomonas spp. Based on all findings, we describe a novel species Pseudomonas gregormendelii sp. nov. with the type strain CCM 8506(T) (=LMG 28632T)

Progressive multifocal leukoencephalopathy - Epidemiology, immune response, clinical differences, treatment

Progressive multifocal leukoencephalopathy (PML) is a severe disease of the central nervous system with very high mortality. It is caused by the JC virus with high seroprevalence, at up to 80%. Development of PML is typically opportunistic, particularly in acquired immunodeficiency syndrome, and usually affects patients with profound immunodeficiency. Furthermore, as a result of highly efficient immunosuppressive and immunomodulatory treatments in recent years, the number of PML cases has increased in the general population. In this article, the authors mention virological and epidemiological relationships and characteristic manifestations of PML. Possible relationships of humoral and cellular immunity are discussed and limited treatment options including prophylaxis are mentioned. © 2019, Czech Medical Association J.E. Purkyne. All rights reserved