Resuscitation of the viable but non-culturable state of Salmonella enterica serovar Oranienburg by recombinant resuscitation-promoting factor derived from Salmonella Typhimurium strain LT2.
A gene encoding the resuscitation-promoting factor (Rpf) from Salmonella Typhimurium LT2 was cloned and characterized. The amino acid sequence encoded by S. Typhimurium LT2 rpf gene shares 24.2% homology with Micrococcus luteus Rpf, which is secreted by growing cells, and required to resuscitate from viable but non-culturable (VNC) state. The S. Typhimurium LT2 rpf gene is 696 bp long, and shared a conserved segment with Salmonella enterica serovar Oranienburg (99.4%). Recombinant Rpf (rRpf) proteins of S. Typhimurium LT2 after expression in E. coli BL21 harboring the pET15-b plasmid was approximately 25 kDa. Since S. Oranienburg cells are relatively quick to enter the VNC state just after incubating in the presence of 7% NaCl at 37 degrees C for 3 days, we evaluated the biological effect of rRpf by using S. Oranienburg VNC cells. The rRpf not only promoted proliferation but also induced resuscitation of VNC cells to the culturable state in a dose-dependent manner. Therefore, rRpf may be useful for detection of bacterial contaminants present in the VNC form in food samples and the environment.
Panutdaporn
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N
Research Center for Animal Hygiene and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.
Kawamoto
K
K
Asakura
H
H
Makino
S-I
SI
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D015169:Colony Count, Microbial; D003470:Culture Media; D016207:Cytokines / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005516:Food Microbiology; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D012478:Salmonella Food Poisoning / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects / Q000254:growth & development*; D012486:Salmonella typhimurium / Q000737:chemistry / Q000235:genetics*; D012692:Serial Passage; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors
D001426:Bacterial Proteins; D003470:Culture Media; D016207:Cytokines; D011994:Recombinant Proteins; C113704:resuscitation-promoting factor, bacteria; D012965:Sodium Chloride