Actinobacteria (Actinomycetes) are a significant and interesting group of gram-positive bacteria. They are regular, though infrequent, members of the microbial life in the rumen and represent up to 3 % of total rumen bacteria; there is considerable lack of information about ecology and biology of rumen actinobacteria. During the characterization of variability of rumen treponemas using non-cultivation approach, we also noted the variability of rumen actinobacteria. By using Treponema-specific primers a specific 16S rRNA gene library was prepared from cow and sheep rumen total DNA. About 10 % of recombinant clones contained actinobacteria-like sequences. Phylogenetic analyses of 11 clones obtained showed the high variability of actinobacteria in the ruminant digestive system. While some sequences are nearly identical to known sequences of actinobacteria, we detected completely new clusters of actinobacteria-like sequences, representing probably new, as yet undiscovered, group of rumen Actinobacteria. Further research will be necessary for understanding their nature and functions in the rumen.

• MeSH
• Actinobacteria classification   genetics   isolation & purification   MeSH
• Rumen microbiology   MeSH
• Biodiversity MeSH
• DNA, Bacterial genetics   MeSH
• Phylogeny MeSH
• Molecular Sequence Data MeSH
• Sheep MeSH
• DNA, Ribosomal genetics   MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Cattle MeSH
• Animals MeSH
• Check Tag
• Cattle MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• DNA, Bacterial MeSH
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 16S MeSH

Complete 16S rRNA sequences were determined of recently proposed new species of treponemes designated strain S and T. Sequence comparison indicated that both species belong to the Treponema saccharophilum cluster, having thus at least 5 cultivable representatives. Phylogenetic analysis of available GenBank 16S rRNA sequences revealed two phylogenetically distant treponema clusters (T. saccharophilum cluster and T. bryantii cluster). Surprisingly, while among cultivated treponemes dominate T. saccharophilum cluster members, detailed analysis showed that all treponema-like sequences obtained by culture independent 16S rRNA methods belong to the T. bryantii cluster, from which only two cultivable representatives have so far been known. Meta-analysis of available data revealed that treponemes are an infrequent and minor group of bacteria, representing less than 2.4% of total rumen bacteria.

• MeSH
• Rumen microbiology   MeSH
• DNA, Bacterial chemistry   genetics   MeSH
• Phylogeny MeSH
• Molecular Sequence Data MeSH
• Colony Count, Microbial MeSH
• Ruminants microbiology   MeSH
• DNA, Ribosomal chemistry   genetics   MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Sequence Analysis, DNA MeSH
• Cluster Analysis MeSH
• Treponema classification   isolation & purification   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA, Bacterial MeSH
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 16S MeSH

Genome analysis of Treponema zioleckii proved that, in this bacterium, besides chromosomal DNA, a relatively small extrachromosomal DNA element is present. This element was shown to be a double-stranded circular plasmid DNA of approximately 7 kbp; it was designated as pKT. The plasmid was characterized by molecular and bioinformatic analysis. No pKT homologous DNA sequences were detected in other rumen Treponema strains. The overall G+C content of the pKT plasmid is approximately 56 %, which is higher than in other Treponema plasmids or genomes. The Rep module of the pKT plasmid consisting of the rep gene and the region of repeats was identified within a 1.6-kbp fragment. The putative rep gene encodes the replication protein belonging to the pfam04796 RepA_C family of proteins with the highest similarity (25 % within 249 amino acids) to the RepA protein from the green sulfur bacterium Prosthecochloris aestuarii.

• MeSH
• Rumen microbiology   MeSH
• Bacterial Proteins genetics   MeSH
• DNA, Bacterial analysis   isolation & purification   MeSH
• Phylogeny MeSH
• Genome, Bacterial * MeSH
• Nucleic Acid Hybridization MeSH
• Molecular Sequence Data MeSH
• Sheep MeSH
• Plasmids genetics   MeSH
• DNA Replication MeSH
• Amino Acid Sequence MeSH
• Sequence Analysis, DNA MeSH
• Treponema genetics   isolation & purification   MeSH
• Base Composition MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bacterial Proteins MeSH
• DNA, Bacterial MeSH

Bacterial 16S rDNA from fecal samples of two calves were amplified by PCR and analyzed by denaturing gradient gel electrophoresis; selected bands were sequenced. Escherichia coli and Bifidobacterium animalis were the initial colonizers, followed by species closely related to the genera Bacteroides, Clostridium and Faecalibacterium. Change of diet was connected with shifts of bacterial population and with the occurrence of many bacterial species that have not been cultured up to now. The diet change corresponded with an alteration in a volatile-fatty-acid concentration in fecal samples.

• MeSH
• Bacteria classification   genetics   growth & development   isolation & purification   MeSH
• Bifidobacterium genetics   growth & development   isolation & purification   MeSH
• DNA, Bacterial analysis   MeSH
• Ecosystem MeSH
• Electrophoresis methods   MeSH
• Escherichia coli genetics   growth & development   isolation & purification   MeSH
• Feces microbiology   MeSH
• Gastrointestinal Tract microbiology   MeSH
• Animals, Newborn * MeSH
• Polymerase Chain Reaction methods   MeSH
• DNA, Ribosomal analysis   MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Sequence Analysis, DNA MeSH
• Cattle * MeSH
• Animals MeSH
• Check Tag
• Cattle * MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA, Bacterial MeSH
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 16S MeSH