Sanz Y, Hernández M, Ferrús M A, Hernández J
Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Universidad Politécnica, Valencia, Spain.
J Appl Microbiol. 1998 Apr;84(4):600-6. doi: 10.1046/j.1365-2672.1998.00387.x.
Lactobacillus sake strains originally isolated from dry-fermented sausages were characterized by phenotypic and genotypic methods, including DNA-DNA hybridization, restriction fragment length polymorphism (RFLP), and 16S rDNA sequencing analysis, in order to establish their taxonomic position and relation to well defined reference species. Initially, isolates of Lact. sake showing a characteristic phenotype (melibiose-positive, maltose- and arabinose-negative) were identified by DNA-DNA hybridization. Subsequently, RFLP studies using EcoRI and HindIII as restriction enzymes, and cDNA from Escherichia coli or 16S rDNA from Lact. sake strains as probes, showed distinct polymorphism levels. Thus, EcoRI-digested DNA probed with cDNA from E. coli disclosed the presence of a unique cluster for the meat isolates tested, allowing their differentiation from the reference type strain. When HindIII-digested DNA was hybridized with the cDNA probe, strain-specific patterns were obtained, showing a higher discrimination power. Considerable strain differentiation was also observed when EcoRI and HindIII digests were hybridized with 16S rDNA probes. Finally, sequence analysis of the 16S rDNA from one isolate also revealed a certain degree of genetic variability with respect to the reference strain of Lact. sake.
为了确定从干发酵香肠中最初分离出的清酒乳杆菌菌株的分类地位及其与明确的参考菌株的关系，采用了包括DNA-DNA杂交、限制性片段长度多态性（RFLP）和16S rDNA测序分析在内的表型和基因型方法对其进行了特征分析。最初，通过DNA-DNA杂交鉴定出表现出特征性表型（蜜二糖阳性、麦芽糖和阿拉伯糖阴性）的清酒乳杆菌分离株。随后，以大肠杆菌的cDNA或清酒乳杆菌菌株的16S rDNA为探针，使用EcoRI和HindIII作为限制性内切酶进行RFLP研究，结果显示出不同的多态性水平。因此，用大肠杆菌的cDNA探测经EcoRI消化的DNA，揭示了所测试的肉类分离株中存在一个独特的簇，从而使其能够与参考模式菌株区分开来。当用cDNA探针与经HindIII消化的DNA杂交时，获得了菌株特异性模式，显示出更高的鉴别力。当用16S rDNA探针与EcoRI和HindIII消化产物杂交时，也观察到了明显的菌株分化。最后，对一个分离株的16S rDNA进行序列分析，结果还显示出该分离株与清酒乳杆菌参考菌株相比存在一定程度的遗传变异性。
