title: Biological characteristics of staphylococcal enterotoxin Q and its potential risk for food poisoning.
abstract: OBJECTIVE
  To elucidate the biological characteristics and stability of a newly identified staphylococcal enterotoxin Q (SEQ) against heating and digestive enzymes and to evaluate the risk of seq-harbouring Staphylococcus aureus in food poisoning.
  
  
  RESULTS
  Purified SEQ was treated with heating, pepsin and trypsin which are related to food cooking, stomach and intestine conditions, respectively. Superantigenic activity of SEQ was assessed by determining the ability of IL-2 induction in mouse spleen cells. The emetic activity of SEQ was assessed using house musk shrew, a small emetic animal model. The results revealed that SEQ exhibits a remarkable resistance to heat treatment and pepsin digestion and has significant superantigenic and emetic activities. Furthermore, a sandwich ELISA for detection of SEQ production was developed, and the results showed that seq-harboring S. aureus isolates produce a large amount of SEQ.
  
  
  CONCLUSIONS
  The newly identified SEQ had remarkable stability to heat treatment and digestive enzyme degradation and exhibited significant superantigenic and emetic activities. In addition, seq-harbouring S. aureus isolated from food poisoning outbreaks produced a large amount of SEQ, suggesting that seq-harbouring S. aureus could potentially be a hazard for food safety.
  
  
  CONCLUSIONS
  This study found, for the first time, that SEQ, a nonclassical SE, had remarkable stability to heat treatment and enzyme degradation and exhibited significant emetic activity, indicating that SEQ is a high-risk toxin in food poisoning.
authors.affiliation: College of Veterinary Medicine, Jilin University, Changchun, Jiling, China.|Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.|Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
authors.forename: D-L
authors.initials: DL
authors.lastname: Hu
authors.affiliation: Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.|Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
authors.forename: H K
authors.initials: HK
authors.lastname: Ono
authors.affiliation: Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Isayama
authors.affiliation: Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Okada
authors.affiliation: Department of Zoonoses, Kitasato University School of Veterinary Medicine, Towada, Aomori, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okamura
authors.affiliation: College of Veterinary Medicine, Jilin University, Changchun, Jiling, China.
authors.forename: L C
authors.initials: LC
authors.lastname: Lei
authors.affiliation: College of Veterinary Medicine, Jilin University, Changchun, Jiling, China.
authors.forename: Z S
authors.initials: ZS
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Jilin University, Changchun, Jiling, China.
authors.forename: X-C
authors.initials: XC
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Jilin University, Changchun, Jiling, China.
authors.forename: M Y
authors.initials: MY
authors.lastname: Liu
authors.affiliation: College of Life Science, Dalian Minzu University, Dalian, Liaoning, China.
authors.forename: J C
authors.initials: JC
authors.lastname: Cui
authors.affiliation: Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Nakane
mesh_terms: D000818:Animals; D004639:Emetics / Q000494:pharmacology; D004768:Enterotoxins / Q000737:chemistry* / Q000378:metabolism / Q000506:poisoning; D004797:Enzyme-Linked Immunosorbent Assay; D005517:Foodborne Diseases / Q000382:microbiology*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D051379:Mice; D010434:Pepsin A / Q000737:chemistry; D018570:Risk Assessment; D012788:Shrews; D013202:Staphylococcal Food Poisoning; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism; D018089:Superantigens / Q000378:metabolism; D013696:Temperature; D014357:Trypsin / Q000378:metabolism
chemical_list: D004639:Emetics; D004768:Enterotoxins; D007376:Interleukin-2; D018089:Superantigens; D014357:Trypsin; D010434:Pepsin A
keywords: emesis; food poisoning; stability; staphylococcal enterotoxin; superantigen