van Belkum M J, Hayema B J, Jeeninga R E, Kok J, Venema G
Department of Genetics, University of Groningen, Haren, The Netherlands.
Appl Environ Microbiol. 1991 Feb;57(2):492-8. doi: 10.1128/aem.57.2.492-498.1991.
Two distinct regions of the Lactococcus lactis subsp. cremoris 9B4 plasmid p9B4-6, each of which specified bacteriocin production as well as immunity, have been sequenced and analyzed by deletion and frameshift mutation analyses. On a 1.8-kb ScaI-ClaI fragment specifying low antagonistic activity, three open reading frames (ORFs) were present, which were organized in an operon. The first two ORFs, containing 69 and 77 codons, respectively, were involved in bacteriocin activity, whereas the third ORF, containing 154 codons, was essential for immunity. Primer extension analysis indicated the presence of a promoter upstream of the ORFs. Two ORFs were present on a 1.3-kb ScaI-HindII fragment specifying high antagonistic activity. The first ORF, containing 75 codons, specified bacteriocin activity. The second ORF, containing 98 codons, specified immunity. The nucleotide sequences of both fragments upstream of the first ORFs as well as the first 20 bp of the first ORF of both bacteriocin operons appeared to be identical.
乳酸乳球菌乳脂亚种9B4的质粒p9B4 - 6有两个不同区域，通过缺失和移码突变分析对其进行了测序和分析，每个区域都决定了细菌素的产生以及免疫性。在一个指定低拮抗活性的1.8 kb ScaI - ClaI片段上，存在三个开放阅读框（ORF），它们以操纵子形式排列。前两个ORF分别包含69和77个密码子，与细菌素活性有关，而第三个ORF包含154个密码子，对免疫至关重要。引物延伸分析表明在这些ORF上游存在一个启动子。在一个指定高拮抗活性的1.3 kb ScaI - HindII片段上有两个ORF。第一个ORF包含75个密码子，决定细菌素活性。第二个ORF包含98个密码子，决定免疫性。两个细菌素操纵子第一个ORF上游片段的核苷酸序列以及第一个ORF的前20个碱基似乎是相同的。
