ABSTRACT
Nisin is a cationic antimicrobial peptide produced by some lactic acid bacteria. However, expression of nisin resistance protein (NSR) could confer nisin resistance on some non-nisin-producing Lactococcus lactis. To deeply elucidate molecular mechanism underlying NSR-mediated nisin resistance, an NSR mutant with N-terminal 38 amino acid residues deleted (NSR?38) was overexpressed in Escherichia coli by fusion with GST. Purified NSR?38 was obtained through glutathione (GSH) affinity chromatography followed by cleavage of GST tag. Putative proteolytic activity of NSR?38 was determined in vitro against nisin. Antimicrobial activity analysis revealed that nisin lost its bactericidal activity after incubation with NSR?38. Further reversed-phase high performance liquid chromatography (RP-HPLC) analysis indicated that NSR?38 displayed proteolytic activity against nisin, thus inactivating the antimicrobial peptide. The current study paves the way for in-depth functional studies on NSR.
ABSTRACT
BACKGROUND: Many scholars have reported the study of genetic polymorphism of short tandem repeat loci in different countries, areas, and population. But what is the genetic polymorphism of short tandem repeats loci of Chinese Korean is still unknown.OBJECTIVE:To investigate the distribution of the genetic polymorphism of D16S539 D7S820, D13S317, CSF1PO, TPOX and TH01 in Chinese Korean, obtain the crowded genetic data of corresponding polymorphism loci.DESIGN: Single sample observation.SETTING: Staff Room of Biology, Department of Detecting and Analyzing DNA, Mudanjiang Medical College.MATERIALS: Periphoral blood samples from 100 unrelated individuals in Korean of Mudanjiang were chosen from January 2001 to February 2001.METHODS: Genotype detection was performed in one hundred unrelated individuals with polymerase chain reaction amplification fragment length polymorphism analysis.MAIN OUTCOME MEASURES: Sample genotype of D16S539,D7S820, D13S317, CSF1PO, TPOX, THO1 6 short tandem repeat loci.TH01 locus.CONCLUSION: The genotypes distributions of the 6 short tandem repeat (STR) in Chinese Korean met Hardy-Weinberg equilibrium, and have higher heterozygosities. The gene frequency and other data obtained can provide the basis for studying the crowded genetics of Chinese Korean.
ABSTRACT
In organic chemistry teaching,we discuss with our colleagues some aspects such as how to stimulate students'interest in learning to make them have a sense of innovation,how to create the environment of question to form innovative thinking,how to establish the concept of space and develop their innovative thinking,how to conduct exploring experiment to foster their capacity of innovation.
ABSTRACT
<p><b>OBJECTIVE</b>To analyze genetic polymorphism of D16S539 D7S820 D13S317 CSF1PO TPOX and TH01 in Chinese Korean.</p><p><b>METHODS</b>One hundred unrelated individuals were analyzed by PCR amplification fragment length polymorphism analysis.</p><p><b>RESULTS</b>Six alleles and 18 genotypes of D16S539 locus, 7 alleles and 22 genotypes of D7S820 locus, 7 alleles and 23 genotypes of D13S317 locus, 6 alleles and 16 genotypes of CSF1PO locus, 6 alleles and 11 genotypes of TPOX locus, 5 alleles and 12 genotypes of TH01 locus.</p><p><b>CONCLUSION</b>The genotype distribution of all the 6 short tandem repeat(STR) in Chinese Korean met Hardy-Weinberg equilibrium, and have higher heterozygosities. The data obtained can be used in human identity and paternity testing, and in other genetic researches and population investigation.</p>