Publications

4719

A Gram-stain-negative, non-motile, non-spore-forming, long rod-shaped bacterium, designated strain GYP-15T, was isolated from the culture broth of a marine microalga,Picochlorumasp. 122. Phylogenetic analyses revealed that strain GYP-15Tshared 90.6 % 16S rRNA gene sequence similarity with its closest relative,Kangiella aquimarinaKCTC 12183T, and represents a distinct phylogenetic lineage in a robust clade consisting of GYP-15Tand members of the generaKangiellaandPleioneain the orderOceanospirillales. Chemotaxonomic and physiological characteristics, including major cellular fatty acids, NaCl tolerance and pattern of carbon source utilization, could also readily distinguish strain GYP-15Tfrom all established genera and species. Thus, it is concluded that strain GYP-15Trepresents a novel species of a new genus, for which the nameAliikangiella marinagen. nov., sp. nov. is proposed. The type strain ofAliikangiella marinais GYP-15T( = MCCC 1K01163T = KCTC 42667T). Based on phylogenetic results, 16S rRNA gene signature nucleotide pattern and some physiological characteristics, the three generaKangiella,PleioneaandAliikangiellaare proposed to make up a novel family,Kangiellaceaefam. nov., in the orderOceanospirillales.

To improve the knowledge base of Borrelia in north Africa, we tested 257 blood samples collected from febrile patients in Oran, Algeria, between January and December 2012 for Borrelia species using flagellin gene polymerase chain reaction sequencing. A sequence indicative of a new Borrelia sp. named Candidatus Borrelia algerica was detected in one blood sample. Further multispacer sequence typing indicated this Borrelia sp. had 97% similarity with Borrelia crocidurae, Borrelia duttonii, and Borrelia recurrentis. In silico comparison of Candidatus B. algerica spacer sequences with those of Borrelia hispanica and Borrelia garinii revealed 94% and 89% similarity, respectively. Candidatus B. algerica is a new relapsing fever Borrelia sp. detected in Oran. Further studies may help predict its epidemiological importance.

Abstract Methylotrophic planktonic bacteria fulfill a particular role in the carbon cycle of lakes via the turnover of single-carbon compounds. We studied two planktonic freshwater lineages (LD28 and PRD01a001B) affiliated with Methylophilaceae (Betaproteobacteria) in Lake Zurich, Switzerland, by a combination of molecular and cultivation-based approaches. Their spatio-temporal distribution was monitored at high resolution (n=992 samples) for 4 consecutive years. LD28 methylotrophs constituted up to 11 × 107 cells l−1 with pronounced peaks in spring and autumn–winter, concomitant with blooms of primary producers. They were rare in the warm water layers during summer but abundant in the cold hypolimnion, hinting at psychrophilic growth. Members of the PRD01a001B lineage were generally less abundant but also had maxima in spring. More than 120 axenic strains from these so far uncultivated lineages were isolated from the pelagic zone by dilution to extinction. Phylogenetic analysis separated isolates into two distinct genotypes. Isolates grew slowly (μmax=0.4 d−1), were of conspicuously small size, and were indeed psychrophilic, with higher growth yield at low temperatures. Growth was enhanced upon addition of methanol and methylamine to sterile lake water. Genomic analyses of two strains confirmed a methylotrophic lifestyle with a reduced set of genes involved in C1 metabolism. The very small and streamlined genomes (1.36 and 1.75 Mb) shared several pathways with the marine OM43 lineage. As the closest described taxa (Methylotenera sp.) are only distantly related to either set of isolates, we propose a new genus with two species, that is, ‘Candidatus Methylopumilus planktonicus’ (LD28) and ‘Candidatus Methylopumilus turicensis’ (PRD01a001B).