Project description:Improving the health beneficial fatty acid content of meat and milk is a major challenge requiring an increased understanding of rumen lipid metabolism. In this study, we isolated and characterized rumen bacterial lipases/esterases using functional metagenomics. Metagenomic libraries were constructed from DNA extracted from strained rumen fluid (SRF), solid-attached bacteria (SAB) and liquid-associated rumen bacteria (LAB), ligated into a fosmid vector and subsequently transformed into an Escherichia coli host. Fosmid libraries consisted of 7,744; 8,448; and 7,680 clones with an average insert size of 30 to 35 kbp for SRF, SAB and LAB, respectively. Transformants were screened on spirit blue agar plates containing tributyrin for lipase/esterase activity. Five SAB and four LAB clones exhibited lipolytic activity, and no positive clones were found in the SRF library. Fosmids from positive clones were pyrosequenced and twelve putative lipase/esterase genes and two phospholipase genes retrieved. Although the derived proteins clustered into diverse esterase and lipase families, a degree of novelty was seen, with homology ranging from 40 to 78% following BlastP searches. Isolated lipases/esterases exhibited activity against mostly short- to medium-chain substrates across a range of temperatures and pH. The function of these novel enzymes recovered in ruminal metabolism needs further investigation, alongside their potential industrial uses.
Project description:To investigate the evolutionary changes of regulatory elements in ruminants, we then performed regulatory elements profiling analysis using ChIP-seq datasets (H3K27ac and H3K4me3) of liver from three ruminants.
Project description:To investigate the evolutionary changes of gene expression in ruminants, we performed gene expression profiling analysis using RNA-seq data of liver from three ruminants.
Project description:Enterohemorrhagic Escherichia coli (EHEC) are transmitted from cattle to human by means of contaminated food products resulting from fecal contamination. Transcriptome analysis was performed to gain further insight into the metabolic pathways required for persistence and growth of EHEC in the bovine intestine. Understanding the physiology of EHEC in the gut of ruminants is critical to identifying the potential nutritional basis to limiting EHEC shedding. A global transcriptome analysis was performed to gain further insight into the metabolic pathways required for persistence and growth of EHEC in the bovine intestine. DNA microarrays were performed using RNA from EHEC O157:H7 EDL933 incubated in bovine small intestine content (BSIC) compared with cells incubated in M9-minimal media.
Project description:Infections in cattle by the abomasal nematode Ostertagia ostertagi result in impaired gastrointestinal function. Six partially immune animals were developed using multiple drug-attenuated infections, and these animals displayed reduced worm burdens and a slightly elevated abomasal pH upon reinfection. In this study, we characterized the abomasal microbiota in response to reinfection using metagenomic tools. Compared to uninfected controls, infection did not induce a significant change in the microbial community composition in immune animals. 16S rRNA gene-based phylogenetic analysis identified 15 phyla in the bovine abomasal microbiota with Bacteroidetes (60.5%), Firmicutes (27.1%), Proteobacteria (7.2%), Spirochates (2.9%), and Fibrobacteres (1.5%) being the most predominant. The number of prokaryotic genera and operational taxonomic units (OTU) identified in the abomasal microbial community was 70.8±19.8 (mean ± SD) and 90.3±2.9, respectively. However, the core microbiome comprised of 32 genera and 72 OTU. Infection seemingly had a minimal impact on the abomasal microbial diversity at a genus level in immune animals. Proteins predicted from whole genome shotgun (WGS) DNA sequences were assigned to 5,408 Pfam and 3,381 COG families, demonstrating dazzling arrays of functional diversity in bovine abomasal microbial communities. However, none of COG functional classes were significantly impacted by infection. Our results demonstrate that immune animals may develop abilities to maintain proper stability of their abomasal microbial ecosystem. A minimal disruption in the bovine abomasal microbiota by reinfection may contribute equally to the restoration of gastric function in immune animals.
Project description:The study objective was to determine the effects of two treatment regimens on quantities of ceftiofur and tetracycline resistance genes in feedlot cattle. The two regimens were ceftiofur crystalline-free acid (CCFA) administered to either one or all steers within a pen and subsequent feeding/not feeding of therapeutic doses of chlortetracycline. A 26-day randomized controlled field trial was conducted on 176 steers. Real-time PCR was used to quantify bla(CMY-2), bla(CTX-M), tet(A), tet(B), and 16S rRNA gene copies/gram of feces from community DNA. A significant increase in ceftiofur resistance and a decrease in tetracycline resistance elements were observed among the treatment groups in which all steers received CCFA treatment, expressed as gene copies/gram of feces. Subsequent chlortetracycline administration led to rapid expansion of both ceftiofur and tetracycline resistance gene copies/gram of feces. Our data suggest that chlortetracycline is contraindicated when attempting to avoid expansion of resistance to critically important third-generation cephalosporins.
Project description:To describe the gene expression profile of brain and muscle across ruminants, we performed gene expression analysis of brain and muscle using RNA-seq data for three ruminants.
Project description:Enterohemorrhagic Escherichia coli (EHEC) are transmitted from cattle to human by means of contaminated food products resulting from fecal contamination. Transcriptome analysis was performed to gain further insight into the metabolic pathways required for persistence and growth of EHEC in the bovine intestine. Understanding the physiology of EHEC in the gut of ruminants is critical to identifying the potential nutritional basis to limiting EHEC shedding. A global transcriptome analysis was performed to gain further insight into the metabolic pathways required for persistence and growth of EHEC in the bovine intestine. DNA microarrays were performed using RNA from EHEC O157:H7 EDL933 incubated in bovine small intestine content (BSIC) compared with cells incubated in M9-minimal media. Four biological replicates collected for bacterial cultures on separate days for each media and labelled following a dye-switch design : For each media two replicates labeled in Cy3 and two replicates in Cy5.