Bentley R W, Leigh J A
Institute for Animal Health, Newbury, Berkshire, UK.
FEMS Immunol Med Microbiol. 1995 Sep;12(1):1-7. doi: 10.1111/j.1574-695X.1995.tb00167.x.
Species-specific oligonucleotide probes and a universal oligonucleotide probe derived from sequences of 16S rRNA were hybridised to chromosomal DNA from Streptococcus agalactiae, S. dysgalactiae, S. parauberis and S. uberis following digestion with EcoRI. Due to the presence of a unique EcoRI site in each 16S rRNA gene, the number of hybridised fragments was indicative of the number of 16S rRNA genes. Southern hybridisation indicated six 16S rRNA genes in ten isolates of S. agalactiae, five genes in ten isolates of S. uberis, five genes in six isolates and six in another isolate of S. dysgalactiae, and six genes in four isolates of S. parauberis. For a fifth isolate of S. parauberis, six 16S rRNA genes were indicated by the universal probe but only five when hybridised to the species-specific probe, indicating sequence variation (microheterogeneity) within the probe target region.
将源自16S rRNA序列的种特异性寡核苷酸探针和通用寡核苷酸探针，与用EcoRI消化后的无乳链球菌、乳房炎链球菌、副乳房链球菌和乳房链球菌的染色体DNA进行杂交。由于每个16S rRNA基因中存在一个独特的EcoRI位点，杂交片段的数量表明了16S rRNA基因的数量。Southern杂交显示，十株无乳链球菌中有六个16S rRNA基因，十株乳房链球菌中有五个基因，六株乳房炎链球菌中有五个基因，另一株乳房炎链球菌中有六个基因，四株副乳房链球菌中有六个基因。对于第五株副乳房链球菌，通用探针显示有六个16S rRNA基因，但与种特异性探针杂交时只有五个，表明探针靶区域内存在序列变异（微异质性）。
