title: Identification ofAeromonas hydrophilaGenes Preferentially Expressed after Phagocytosis byTetrahymenaand Involvement of Methionine Sulfoxide Reductases.
abstract: Free-living protozoa affect the survival and virulence evolution of pathogens in the environment. In this study, we explored the fate ofAeromonas hydrophilawhen co-cultured with the bacteriovorous ciliateTetrahymena thermophilaand investigated bacterial gene expression associated with the co-culture. VirulentA. hydrophilastrains were found to have ability to evade digestion in the vacuoles of this protozoan. InA. hydrophila, a total of 116 genes were identified as up-regulated following co-culture withT. thermophilaby selective capture of transcribed sequences (SCOTS) and comparative dot-blot analysis. A large proportion of these genes (42/116) play a role in metabolism, and some of the genes have previously been characterized as required for bacterial survival and replication within macrophages. Then, we inactivated the genes encoding methionine sulfoxide reductases,msrA, andmsrB, inA. hydrophila. Compared to the wild-type, the mutants ΔmsrAand ΔmsrABdisplayed significantly reduced resistance to predation byT. thermophila, and 50% lethal dose (LD50) determinations in zebrafish demonstrated that both mutants were highly attenuated. This study forms a solid foundation for the study of mechanisms and implications of bacterial defenses.
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural UniversityNanjing, China; Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety, Jiangsu Academy of Agricultural SciencesNanjing, China.
authors.forename: Maoda
authors.initials: M
authors.lastname: Pang
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Changming
authors.initials: C
authors.lastname: Guo
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Gao
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Hechao
authors.initials: H
authors.lastname: Du
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Chengping
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Liu
mesh_terms: D016980:Aeromonas hydrophila / Q000235:genetics* / Q000502:physiology*; D000818:Animals; D018920:Coculture Techniques; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D007928:Lethal Dose 50; D051150:Methionine Sulfoxide Reductases / Q000235:genetics / Q000378:metabolism*; D050296:Microbial Viability; D010587:Phagocytosis; D013312:Stress, Physiological; D016019:Survival Analysis; D016808:Tetrahymena thermophila / Q000502:physiology*; D014774:Virulence; D015027:Zebrafish
chemical_list: D051150:Methionine Sulfoxide Reductases
keywords: Aeromonas hydrophila; SCOTS; Tetrahymena; msr genes; phagocytosis