Project description:Campylobacter jejuni is the major cause of acute gastroenteritis in the developed world. It is usually acquired through contaminated poultry as C. jejuni causes a silent asymptomatic infection of the chicken. Pathogens face different sources of stress during its transit through the gut. In this study, we describe the ability of C. jejuni to survive nitrosative stress at very low oxygen levels that reflect those in hypoxic gut environments. Specifically, we here explore an innovative model of signal recognition during colonization. We use a diffusion capsule to feed small, diffusible molecules from chicken caecal matter into a microaerobic C. jejuni culture to study the transcriptomic changes mounted as response to chemical signals present in the chicken gut. We find that in early stages of exposure to the caecal contents (10 min) the dual component colonization regulator, dccR, plays an important yet not fully understood role. Although the caecal material contains cyanide derived from plant sources, we find no role for a truncated globin (encoded by ctb), which has previously been implicated in resistance to this haem ligand.
Project description:Bacteroidaceae are common gut microbiota members in all warm-blooded animals. However, if Bacteroidaceae are to be used as probiotics, the species selected for different hosts should reflect the natural distribution. In this study, we therefore evaluated host adaptation of bacterial species belonging to the family Bacteroidaceae. B. dorei, B. uniformis, B. xylanisolvens, B. ovatus, B. clarus, B. thetaiotaomicron and B. vulgatus represented human-adapted species while B. gallinaceum, B. caecigallinarum, B. mediterraneensis, B. caecicola, M. massiliensis, B. plebeius and B. coprocola were commonly detected in chicken but not human gut microbiota. There were 29 genes which were present in all human-adapted Bacteroides but absent from the genomes of all chicken isolates and these included genes required for the pentose cycle, and glutamate or histidine metabolism. These genes were expressed during an in vitro competitive assay, in which human-adapted Bacteroides species overgrew the chicken adapted isolates. Not a single gene specific for the chicken-adapted species was found. Instead, chicken adapted species exhibited signs of frequent horizontal gene transfer, of KUP, linA and sugE genes in particular. The differences in host adaptation should be considered when the new generation of probiotics for humans or chickens is designed.
Project description:This study utilized comparative global gene expression microarray analysis to evaluate the effects of DFM on intestinal immunity of chicken.
Project description:Adaptation to hypoxia is a complicated and important physiological course for organisms, but the genetic mechanism underlying the adaptation is not fully understood yet. Tibetan Chicken (T), an indigenous chicken breed in China which inhabit in high areas with an altitude above 2,900 meters. Shouguang Chicken(S) and Dwarf Recessive White Chicken (DRW), two lowland chicken breeds, were used as control groups. The heart was the first functional organ to develop during the embryonic development. Furthermore, the heart is an efficient energy converter utilizing the most appropriate fuel for a given environment. Therefore, GeneChip® Chicken Genome Array was employed to identify the differentially expressed genes in embryonic hearts of Tibetan Chicken and two lowland chicken breeds in both hypoxic and normoxic incubating environments with a genome wide profile. Keywords: stress response
Project description:This study utilized comparative global gene expression microarray analysis to evaluate the effects of DFM on intestinal immunity of chicken. Two-condition experiment, DFM-fed chickens vs. Non-treated control chickens. Biological replicates: 2 control replicates, 2 DFM-fed replicates with dye-switching.