title: [Assessment on the quality of restriction endonuclease in typing Listeria monocytogenes with pulsed-field gel electrophoreses].
abstract: OBJECTIVE
  To study the relative effective factors of PFGE typing methods of Listeria monocytogenes, and set up this PFGE method of this pathogen digested with Asc I and Apa I.
  
  
  METHODS
  Listeria monocytogenes isolates (including 1/2a, 1/2b, 1/2c, 3a and 4b serovars) from food in China were digested with one brand of Asc I and 5 different brands of Apa I. The better test parameters were studied by the fingerprint patterns.
  
  
  RESULTS
  Digestion with Asc I yielded about 11 distinct fragments, and Apa I yielded similar number of fragments. However, ten percent of strains (1/2a, 1/2b serovars) showed partial digestion with all these brands of restriction endomuclease Apa I, including different enzyme concentration, different temperature and different digestion time.
  
  
  CONCLUSIONS
  AscI was suitable for digestion of all these Listeria monocytogenes isolates (1/2a, 1/2b, 1/2c, 3a and 4b serovars), but Apa I was suitable for most of the isolates (1/2a, 1/2b).
authors.affiliation: Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing 100021, China. fuping_63@126.com
authors.forename: Ping
authors.initials: P
authors.lastname: Fu
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Pei
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Yunchang
authors.initials: Y
authors.lastname: Guo
mesh_terms: D015373:Bacterial Typing Techniques; D016172:DNA Fingerprinting; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D015252:Deoxyribonucleases, Type II Site-Specific; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes; C078382:endodeoxyribonuclease AscI; D015252:Deoxyribonucleases, Type II Site-Specific; C038485:GGGCCC-specific type II deoxyribonucleases