ABSTRACT
A polymerase arrest assay was designed to determine sites of adduction in the human p53 gene induced by incubation with fecal water. Significant formation of adducts was observed on p53 DNA after a 2-h incubation in fecal water from 10 of 17 samples studied. Large sample-to-sample variation was observed. The major sites of polymerase termination occurred at nucleotides 3' to guanine residues. Adduct sites coincided with colorectal cancer p53 mutation "hotspots," highlighting the potential carcinogenicity of fecal material.
Subject(s)
Biomarkers/analysis , DNA Adducts/genetics , Feces/chemistry , Genes, p53 , Intestine, Large/drug effects , Mutagens/adverse effects , Body Water , DNA-Directed DNA Polymerase/drug effects , Humans , Mutagenesis , Polymerase Chain ReactionABSTRACT
Red meat consumption causes a dose-dependent increase in fecal apparent total N-nitroso compounds (ATNC). The genotoxic effects of these ATNCs were investigated using two different Comet assay protocols to determine the genotoxicity of fecal water samples. Fecal water samples were obtained from two studies of a total of 21 individuals fed diets containing different amounts of red meat, protein, heme, and iron. The first protocol incubated the samples with HT-29 cells for 5 min at 4 degrees C, whereas the second protocol used a longer exposure time of 30 min and a higher incubation temperature of 37 degrees C. DNA strand breaks were quantified by the tail moment (DNA in the comet tail multiplied by the comet tail length). The results of the two Comet assay protocols were significantly correlated (r = 0.35, P = 0.003), however, only the second protocol resulted in detectable levels of DNA damage. Inter-individual effects were variable and there was no effect on fecal water genotoxicity by diet (P > 0.20), mean transit time (P = 0.588), or weight (P = 0.705). However, there was a highly significant effect of age (P = 0.019). There was no significant correlation between concentrations of ATNCs in fecal homogenates and fecal water genotoxicity (r = 0.04, P = 0.74). ATNC levels were lower in fecal water samples (272 microg/kg) compared to that of fecal homogenate samples (895 microg/kg) (P < 0.0001). Failure to find dietary effects on fecal water genotoxicity may therefore be attributed to individual variability and low levels of ATNCs in fecal water samples.
Subject(s)
Colon/drug effects , Comet Assay/methods , Ammonia , Body Water , DNA/chemistry , DNA Damage , Diet , Feces , HT29 Cells , Humans , Meat , Models, Statistical , Mutagens , Nitrites , Nitroso Compounds/chemistry , Quality Control , Reproducibility of Results , Temperature , Time FactorsABSTRACT
Morphological, biochemical and molecular genetic studies were carried out on an unknown non-spore-forming, Gram-positive, rod-shaped bacterium that was isolated from dog faeces. The bacterium grew under strictly anaerobic conditions, was asaccharolytic, and possessed a relatively high G + C content of 61 mol%. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that the unidentified bacterium was a member of the family Coriobacteriaceae and represents a hitherto unknown subline within the genus Slackia. Based on the presented findings, a novel species, Slackia faecicanis sp. nov., is described. The type strain of Slackia faecicanis is 5WC12(T) (= CCUG 48399(T) = CIP 108281(T)).
Subject(s)
Actinobacteria/classification , Actinobacteria/isolation & purification , Dogs/microbiology , Feces/microbiology , Actinobacteria/cytology , Actinobacteria/physiology , Anaerobiosis , Animals , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/chemistry , DNA, Bacterial/isolation & purification , DNA, Ribosomal/chemistry , DNA, Ribosomal/isolation & purification , Genes, Bacterial , Genes, rRNA , Molecular Sequence Data , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNAABSTRACT
Morphological, biochemical and molecular genetic studies were carried out on an unknown non-spore-forming, Gram-negative, rod-shaped bacterium which was isolated from dog faeces. The bacterium grew under anaerobic conditions, was asaccharolytic, resistant to 20 % (v/v) bile and was oxidase- and urease-negative. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that the unidentified bacterium clustered with Sutterella wadsworthensis, although a sequence divergence of >5 % indicated that the bacterium from dog faeces represented a previously unrecognized subline within the genus. On the basis of the presented findings, a novel species, Sutterella stercoricanis sp. nov., is described. The type strain of Sutterella stercoricanis is 5BAC4T (= CCUG 47620T = CIP 108024T).
Subject(s)
Alcaligenaceae/classification , Alcaligenaceae/isolation & purification , Feces/microbiology , Alcaligenaceae/cytology , Alcaligenaceae/physiology , Animals , Bile , DNA, Bacterial/chemistry , DNA, Bacterial/isolation & purification , DNA, Ribosomal/chemistry , DNA, Ribosomal/isolation & purification , Dogs , Genes, rRNA , Molecular Sequence Data , Oxidoreductases/analysis , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Urease/analysisABSTRACT
Morphological, biochemical, and molecular genetic studies were performed on an unknown anaerobic, catalase-negative, non-spore-forming, rod-shaped bacterium isolated from dog feces. The unknown bacterium was tentatively identified as a Eubacterium species, based on cellular morphological and biochemical tests. 16S rRNA gene sequencing studies, however, revealed that it was phylogenetically distant from Eubacterium limosum, the type species of the genus Eubacterium. Phylogenetically, the unknown species forms a hitherto unknown sub-line proximal to the base of a cluster of organisms (designated rRNA cluster XVI), which includes Clostridium innocuum, Streptococcus pleomorphus, and some Eubacterium species. Based on both phenotypic and phylogenetic criteria, it is proposed that the unknown bacterium be classified as a new genus and species, Allobaculum stercoricanis. Using a specific rRNA-targeted probe designed to identify Allobaculum stercoricanis, in situ hybridisation showed this novel species represents a significant organism in canine feces comprising between 0.1% and 3.7% of total cells stained with DAPI (21 dog fecal samples). The type strain of Allobaculum stercoricanis is DSM 13633(T)=CCUG 45212(T).
ABSTRACT
Morphological, biochemical and molecular genetic studies were performed on an unknown, anaerobic, rod-shaped organism isolated from faeces of a canine. The organism was tentatively identified as a member of the genus Clostridium based on its cellular morphology and ability to form endospores but, biochemically, it did not appear to correspond to any recognized species of this genus. Comparative 16S rRNA gene sequence analysis showed that the bacterium represents a previously unrecognized subline within Clostridium rRNA group I (Clostridium sensu stricto), which includes Clostridium butyricum, the type species of the genus. The nearest phylogenetic relatives of the unknown bacterium corresponded to Clostridium absonum, Clostridium baratii, Eubacterium budayi, Eubacterium moniliforme, Eubacterium multiforme and Eubacterium nitritogenes, but 16S rRNA sequence divergence values of > 3% demonstrated that it represents a novel species. Based on the findings presented, a novel species, Clostridium colicanis sp. nov., is described, with the type strain 3WC2T (=CCUG 44556T =DSM 13634T).
