Nitrospirales, including the genus Nitrospira, are environmentally widespread chemolithoautotrophic nitrite-oxidizing bacteria. These mostly uncultured microorganisms gain energy through nitrite oxidation, fix CO2, and thus play vital roles in nitrogen and carbon cycling. Over the last decade, our understanding of their physiology has advanced through several new discoveries, such as alternative energy metabolisms and complete ammonia oxidizers (comammox Nitrospira). These findings mainly resulted from studies of terrestrial species, whereas less attention has been given to marine Nitrospirales. In this study, we cultured three new marine Nitrospirales enrichments and one isolate. Three of these four NOB represent new Nitrospira species while the fourth represents a novel genus. This fourth organism, tentatively named "Ca. Nitronereus thalassa", represents the first cultured member of a Nitrospirales lineage that encompasses both free-living and sponge-associated nitrite oxidizers, is highly abundant in the environment, and shows distinct habitat distribution patterns compared to the marine Nitrospira species. Partially explaining this, "Ca. Nitronereus thalassa" harbors a unique combination of genes involved in carbon fixation and respiration, suggesting differential adaptations to fluctuating oxygen concentrations. Furthermore, "Ca. Nitronereus thalassa" appears to have a more narrow substrate range compared to many other marine nitrite oxidizers, as it lacks the genomic potential to utilize formate, cyanate, and urea. Lastly, we show that the presumed marine Nitrospirales lineages are not restricted to oceanic and saline environments, as previously assumed.

• MeSH
• amoniak metabolismus   MeSH
• Bacteria * MeSH
• dusitany * metabolismus   MeSH
• fylogeneze MeSH
• genomika MeSH
• nitrifikace MeSH
• oxidace-redukce MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• amoniak MeSH
• dusitany * MeSH

The order Lactobacillales represents a morphologically, metabolically, and physiologically diverse group of bacteria. Lactic acid bacteria represent the core of this phylogenetic group. They are a part of epiphytic microflora, fermented dairy, meat, fruit and vegetable products, and the digestive tract of humans and animals. Despite the fact that these bacteria form a phenotypically and genotypically heterogeneous group, their phylogenetic relationship enables to propose a common genetic marker usable in classification, typing, and phylogeny. By creation of consensus sequence based on available genomic sequences of some representatives of order Lactobacillales, a specific primer-pair binding variable region of aspS gene (length of 615 nts) encoding the aspartyl-tRNA synthetase was designed. This gene has not yet been used in classification and phylogeny of the order Lactobacillales, although it meets the requirements of molecular markers (distribution and single copy in bacterial genomes, functional constancy and genetic stability, sequence variability among taxonomic units, irreplaceable role in proteosynthesis). Primers were applied on 54 type and wild Lactobacillales strains. Obtained sequences allowed to provide alignments for purpose of phylogenetic tree reconstructions that uncovered particular phylogenetic clusters of vagococci/enterococci, obligately homofermentative and heterofermentative lactobacilli. Although a relatively short fragment of the aspS gene (approximately 33% of the complete gene sequence) was evaluated, much higher sequence variability (61.8% of pairwise identity) among strains examined compared with 16S rRNA gene (90.7%, length of 1318 nt) provides a relatively simple and effective tool for classification and typing of selected representatives of the order Lactobacillales.

• MeSH
• aspartát-tRNA-ligasa genetika   MeSH
• bakteriální geny MeSH
• bakteriální proteiny genetika   MeSH
• DNA bakterií genetika   MeSH
• esenciální geny MeSH
• fylogeneze * MeSH
• genetické markery MeSH
• Lactobacillales klasifikace   enzymologie   genetika   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• aspartát-tRNA-ligasa MeSH
• bakteriální proteiny MeSH
• DNA bakterií MeSH
• genetické markery MeSH
• RNA ribozomální 16S MeSH

Gram-stain-positive, catalase and oxidase-negative and short rod-shaped bacterium C10 with occasional branching was isolated under strictly anaerobic conditions from the rumen fluid of a red deer (Cervus elaphus) in the course of study attempting to uncover new xylanolytic and cellulolytic rumen bacteria inhabiting the digestive tract of wild ruminants in the Czech Republic. The anaerobic M10 medium containing bovine rumen fluid and carboxymethylcellulose as a defined source of organic carbon was used in the process of bacterial isolation. The 16S rRNA gene similarity revealed recently characterized new species Actinomyces succiniciruminis Am4T (GenBank accession number of the gene retrieved from the complete genome: LK995506) and Actinomyces glycerinitolerans G10T (GenBank accession number from the complete genome: NZFQTT01000017) as the closest relatives (99.7 and 99.6% gene pairwise identity, respectively), followed by the Actinomyces ruminicola DSM 27982T (97.2%, in all compared fragment of 41468 pb). Due to the taxonomic affinity of the examined strain to both species A. succiniciruminis and A. glycerinitolerans, its taxonomic status towards these species was evaluated using variable regions of rpsA (length of 519 bp) and rplB (597 bp) gene sequences amplified based on specific primers designed so as to be applicable in differentiation, classification, and phylogeny of Actinomyces species/strains. Comparative analyses using rpsA and rplB showed 98.5 and 97.9% similarities of C10 to A. succiniciruminis, respectively, and 97.5 and 97.6% similarities to A. glycerinitolerans, respectively. Thus, gene identities revealed that the evaluated isolate C10 (=DSM 100236 = LMG 28777) is a little more related to the species A. succiniciruminis isolated from the rumen of a Holstein-Friesian cow than A. glycerinitolerans. Phylogenetic analyses confirmed affinity of strain C10 to both recently characterized species. Unfortunately, they did not allow the bacterial strain to be classified into a particular species. Phenotypic characterization suggested similar conclusions. This brief contribution is aimed at classification and detailed phenotypic characterization of bacterial strain C10 isolated from the rumen of a wild red deer exhibiting, from the point of view of Actinomyces species, noteworthy cellulolytic and xylanolytic activities.

• MeSH
• Actinomyces klasifikace   genetika   izolace a purifikace   metabolismus   MeSH
• bachor mikrobiologie   MeSH
• bakteriální geny genetika   MeSH
• celulosa metabolismus   MeSH
• DNA bakterií genetika   MeSH
• fenotyp MeSH
• fylogeneze MeSH
• mastné kyseliny analýza   MeSH
• peptidoglykan analýza   MeSH
• RNA ribozomální 16S genetika   MeSH
• vysoká zvěř mikrobiologie   MeSH
• xylany metabolismus   MeSH
• zastoupení bazí MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• celulosa MeSH
• DNA bakterií MeSH
• mastné kyseliny MeSH
• peptidoglykan MeSH
• RNA ribozomální 16S MeSH
• xylany MeSH

Amoebae play an important ecological role as predators in microbial communities. They also serve as niche for bacterial replication, harbor endosymbiotic bacteria and have contributed to the evolution of major human pathogens. Despite their high diversity, marine amoebae and their association with bacteria are poorly understood. Here we describe the isolation and characterization of two novel marine amoebae together with their bacterial endosymbionts, tentatively named 'Candidatus Occultobacter vannellae' and 'Candidatus Nucleophilum amoebae'. While one amoeba strain is related to Vannella, a genus common in marine habitats, the other represents a novel lineage in the Amoebozoa. The endosymbionts showed only low similarity to known bacteria (85-88% 16S rRNA sequence similarity) but together with other uncultured marine bacteria form a sister clade to the Coxiellaceae. Using fluorescence in situ hybridization and transmission electron microscopy, identity and intracellular location of both symbionts were confirmed; one was replicating in host-derived vacuoles, whereas the other was located in the perinuclear space of its amoeba host. This study sheds for the first time light on a so far neglected group of protists and their bacterial symbionts. The newly isolated strains represent easily maintainable model systems and pave the way for further studies on marine associations between amoebae and bacterial symbionts.

• MeSH
• Amoeba klasifikace   mikrobiologie   MeSH
• buněčné jádro mikrobiologie   MeSH
• cytoplazma mikrobiologie   MeSH
• druhová specificita MeSH
• Gammaproteobacteria klasifikace   izolace a purifikace   fyziologie   MeSH
• symbióza fyziologie   MeSH
• vodní organismy klasifikace   izolace a purifikace   mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Permafrost-affected soils in the Northern latitudes store huge amounts of organic carbon (OC) that is prone to microbial degradation and subsequent release of greenhouse gasses to the atmosphere. In Greenland, the consequences of permafrost thaw have only recently been addressed, and predictions on its impact on the carbon budget are thus still highly uncertain. However, the fate of OC is not only determined by abiotic factors, but closely tied to microbial activity. We investigated eight soil profiles in northeast Greenland comprising two sites with typical tundra vegetation and one wet fen site. We assessed microbial community structure and diversity (SSU rRNA gene tag sequencing, quantification of bacteria, archaea and fungi), and measured hydrolytic and oxidative enzyme activities. Sampling site and thus abiotic factors had a significant impact on microbial community structure, diversity and activity, the wet fen site exhibiting higher potential enzyme activities and presumably being a hot spot for anaerobic degradation processes such as fermentation and methanogenesis. Lowest fungal to bacterial ratios were found in topsoils that had been relocated by cryoturbation ("buried topsoils"), resulting from a decrease in fungal abundance compared to recent ("unburied") topsoils. Actinobacteria (in particular Intrasporangiaceae) accounted for a major fraction of the microbial community in buried topsoils, but were only of minor abundance in all other soil horizons. It was indicated that the distribution pattern of Actinobacteria and a variety of other bacterial classes was related to the activity of phenol oxidases and peroxidases supporting the hypothesis that bacteria might resume the role of fungi in oxidative enzyme production and degradation of phenolic and other complex substrates in these soils. Our study sheds light on the highly diverse, but poorly-studied communities in permafrost-affected soils in Greenland and their role in OC degradation.

• Klíčová slova
• Greenland, climate change, extracellular enzyme activities, microbial communities, permafrost-affected soils,
• Publikační typ
• časopisecké články MeSH

Bacterial clone libraries of the gut microbiota of nurtured and starved Cylindroiulus fulviceps specimens displayed the predominance of the phyla Bacteroidetes (55 and 37 %, respectively) and Proteobacteria (40 and 35 %, respectively) and a high similarity to bacteria previously detected in the intestinal tract of termites and beetles, which are known to harbor symbiotic bacteria essential for digestive activity. Bacterial isolates were dominated by Proteobacteria (74 %), followed by members of the phyla Actinobacteria, Firmicutes and Bacteroidetes. PCR-DGGE fingerprints of the gut samples showed that intestinal bacteria were affected by starvation, although the change was not significant.

• MeSH
• Actinobacteria klasifikace   genetika   izolace a purifikace   MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• Bacteroidetes klasifikace   genetika   izolace a purifikace   MeSH
• bakteriologické techniky MeSH
• členovci mikrobiologie   MeSH
• DNA bakterií genetika   MeSH
• DNA fingerprinting metody   MeSH
• ekosystém MeSH
• elektroforéza v agarovém gelu metody   MeSH
• fylogeneze MeSH
• gastrointestinální trakt mikrobiologie   MeSH
• klonování DNA metody   MeSH
• kultivační média MeSH
• metagenom MeSH
• molekulární sekvence - údaje MeSH
• Proteobacteria klasifikace   genetika   izolace a purifikace   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA bakterií MeSH
• kultivační média MeSH
• RNA ribozomální 16S MeSH