title: Transducer like proteins of Campylobacter jejuni 81-176: role in chemotaxis and colonization of the chicken gastrointestinal tract.
abstract: Transducer Like Proteins (Tlps), also known as methyl accepting chemotaxis proteins (MCP), enable enteric pathogens to respond to changing nutrient levels in the environment by mediating taxis toward or away from specific chemoeffector molecules. Despite recent advances in the characterization of chemotaxis responses in Campylobacter jejuni, the impact of Tlps on the adaptation of this pathogen to disparate niches and hosts is not fully characterized. The latter is particularly evident in the case of C. jejuni 81-176, a strain that is known to be highly invasive. Furthermore, the cytoplasmic group C Tlps (Tlp5, 6, and 8) were not extensively evaluated. Here, we investigated the role of C. jejuni 81-176 Tlps in chemotaxis toward various substrates, biofilm formation, in vitro interaction with human intestinal cells, and chicken colonization. We found that the Δtlp6 and Δtlp10 mutants exhibited decreased chemotaxis toward aspartate, whereas the Δtlp6 mutant displayed a decreased chemotaxis toward Tri-Carboxylic Acid (TCA) cycle intermediates such as pyruvate, isocitrate, and succinate. Our findings also corroborated that more than one Tlp is involved in mediating chemotaxis toward the same nutrient. The deletion of tlps affected important phenotypes such as motility, biofilm formation, and invasion of human intestinal epithelial cells (INT-407). The Δtlp8 mutant displayed increased motility in soft agar and showed decreased biofilm formation. The Δtlp8 and Δtlp9 mutants were significantly defective in invasion in INT-407 cells. The Δtlp10 mutant was defective in colonization of the chicken proximal and distal gastrointestinal tract, while the Δtlp6 and Δtlp8 mutants showed reduced colonization of the duodenum and jejunum. Our results highlight the importance of Tlps in C. jejuni's adaptation and pathobiology.
authors.affiliation: Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA.
authors.forename: Kshipra
authors.initials: K
authors.lastname: Chandrashekhar
authors.affiliation: Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA.
authors.forename: Dharanesh
authors.initials: D
authors.lastname: Gangaiah
authors.affiliation: Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA.
authors.forename: Ruby
authors.initials: R
authors.lastname: Pina-Mimbela
authors.affiliation: Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA.
authors.forename: Issmat I
authors.initials: II
authors.lastname: Kassem
authors.affiliation: Department of Environmental Health Sciences, School of Public Health, University of Alberta Edmonton, AB, Canada.
authors.forename: Byeong H
authors.initials: BH
authors.lastname: Jeon
authors.affiliation: Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA.
authors.forename: Gireesh
authors.initials: G
authors.lastname: Rajashekara
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D002169:Campylobacter Infections / Q000382:microbiology / Q000662:veterinary*; D016123:Campylobacter jejuni / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D002633:Chemotaxis; D002645:Chickens; D004705:Endocytosis; D004847:Epithelial Cells / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D017353:Gene Deletion; D006801:Humans; D008124:Locomotion; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D037521:Virulence Factors
keywords: amino acids; chemotaxis; chicken; colonization; methyl accepting chemoreceptors; motility; organic acids; virulence