CRISPR1 analysis of naturalized surface water and fecal Escherichia coli suggests common origin.

Clustered regularly interspaced short palindromic repeats (CRISPRs) are part of an acquired bacterial immune system that functions as a barrier to exogenous genetic elements. Since naturalized Escherichia coli are likely to encounter different genetic elements in aquatic environments compared to enteric strains, we hypothesized that such differences would be reflected within the hypervariable CRISPR alleles of these two populations. Comparison of CRISPR1 alleles from naturalized and fecal phylogroup B1 E.

Campylobacter jejuni increases flagellar expression and adhesion of noninvasive Escherichia coli: effects on enterocytic Toll-like receptor 4 and CXCL-8 expression.

Campylobacter jejuni is the most common cause of bacterium-induced gastroenteritis, and while typically self-limiting, C. jejuni infections are associated with postinfectious intestinal disorders, including flares in patients with inflammatory bowel disease and postinfectious irritable bowel syndrome (PI-IBS), via mechanisms that remain obscure. Based on the hypothesis that acute campylobacteriosis may cause pathogenic microbiota dysbiosis, we investigated whether C.

Structures of free-living and protozoa-associated methanogen communities in the bovine rumen differ according to comparative analysis of 16S rRNA and mcrA genes.

Structures of free-living and protozoa-associated methanogen (PAM) communities from forage-fed cattle were investigated by comparative sequence analysis of 16S rRNA and methyl coenzyme M reductase (mcrA) gene clone libraries. The free-living and protozoa-associated communities were composed of the same three genera [namely Methanobrevibacter, Methanomicrobium and rumen cluster C (RCC), which is distantly related to Thermoplasma]; however, the distribution of the methanogen genera differed between the two communities. Despite previous reports of potential bias for the degenerate mcrA primer set, the 16S rRNA (n = 100 clones) and mcrA (n = 92 clones) gene libraries exhibited a similar distribution pattern for the three methanogenic genera.

Community structure analysis of methanogens associated with rumen protozoa reveals bias in universal archaeal primers.

The diversity of protozoan-associated methanogens in cattle was investigated using five universal archaeal small-subunit (SSU) rRNA gene primer sets. Methanobrevibacter spp. and rumen cluster C (distantly related to Thermoplasma spp.