ABSTRACT
<p><b>OBJECTIVE</b>To isolate and identify nisin resistance determinant (NSR) gene from Lactococcus lactis.</p><p><b>METHODS</b>The Lactococcus lactis strains harboring NSR gene were isolated from different milk samples by selective culture supplemented with nisin and confirmed by PCR detection of 16S rRNA. Nisin resistance determinant gene was determined by PCR amplification, enzyme digestion and sequencing.</p><p><b>RESULTS</b>Thirty nisin-resistant Lactococcus lactis strains from fresh milk samples were obtained. Three of these strains contained NSR gene of about 1000 bp as determined by agarose gel electrophoresis and further confirmed by enzyme digestion and sequence analysis. The NSR gene was located on the plasmid of Lactococcus lactis.</p><p><b>CONCLUSION</b>Complete NSR gene, located on the bacterial plasmid, has been successfully isolated from nisin-resistant Lactococcus lactis strains from fresh milk.</p>
Subject(s)
Animals , Cattle , Anti-Bacterial Agents , Pharmacology , Drug Resistance, Bacterial , Genetics , Lactococcus lactis , Genetics , Milk , Microbiology , Nisin , Genetics , Pharmacology , Plasmids , Genetics , Polymerase Chain Reaction , RNA, Ribosomal, 16S , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To detect serve acute respiratory syndrome-associated coronavirus (SARS-CoV) and SARS-like-CoV in fruit bats captured in Guangzhou and its vicinity.</p><p><b>METHODS</b>Totally 927 bats of 9 species (Cynopterus sphinx, Rousettus leschenaulti, Miniopterus schreibersi, Hipposideros pratti, Rhinolophusasinicus, Scotophilusakuhlii, Hipposideros Pomona, Rhinolophus affinis, and Rhinolophus pusillus) captured in Guangzhou and its vicinity from September 2004 to November 2005 were available for this investigation, from which 3,043 samples (813 throat swasb, 524 sera, 853 lung tissues and 853 colorectal tissue specimens) were obtained. SARS-Cov and SARS-like-CoV were detected in these specimens using diagnostic kit for novel coronavirus N protein (ELISA), SARS-CoV Virus RNA detection kit, fluorescence PCR, Genchip, RT-PCR and cell isolation culture methods.</p><p><b>RESULTS AND CONCLUSION</b>No SARS-CoV and SARS-like-CoV were detected in the 3043 samples, indicating the current absence of SARS-CoV and SARS-like-CoV in the bats captured in Guangzhou and its vicinity.</p>