Klijn N, Weerkamp A H, de Vos W M
NIZO, Ede, The Netherlands.
Appl Environ Microbiol. 1995 Feb;61(2):788-92. doi: 10.1128/aem.61.2.788-792.1995.
The presence of lactose-utilizing Lactococcus species in nondairy environments was studied by using identification methods based on PCR amplification and (sub)species-specific probes derived from 16S rRNA sequences. Environmental isolates from samples taken on cattle farms and in the waste flow of a cheese production plant were first identified to the genus level, using a Lactococcus genus-specific probe. Isolates which showed a positive signal with this probe were further identified to the (sub)species level. Lactococcus lactis isolates were also characterized at the phenotypic level for the ability to hydrolyze arginine, to ferment citrate, and to produce proteases and bacteriocins. With specific PCR amplifications, the presence of sequences related to citP, coding for citrate permease; prtP, coding for protease; and nisA or nisZ, the structural genes for production of nisin A or nisin Z, respectively, was verified. By these methods, it was possible to isolate lactococci from various environmental sources, such as soil, effluent water, and the skin of cattle. The strains of L. lactis isolated differed in a number of properties, such as the ability to hydrolyze arginine or the absence of citP-related sequences, from those found in industrial starter cultures. The results indicate that the majority of the industrially produced lactococci do not survive outside the dairy environment, although natural niches are available. However, from those niches strains with the potential to be developed into novel starter cultures may be isolated.
通过使用基于PCR扩增和源自16S rRNA序列的（亚）种特异性探针的鉴定方法，研究了非乳制品环境中利用乳糖的乳球菌属物种的存在情况。首先使用乳球菌属特异性探针将从奶牛场采集的样本以及奶酪生产厂废水中分离得到的环境菌株鉴定到属水平。对该探针呈阳性信号的菌株进一步鉴定到（亚）种水平。还对乳酸乳球菌分离株在表型水平上进行了水解精氨酸、发酵柠檬酸盐以及产生蛋白酶和细菌素能力的表征。通过特异性PCR扩增，验证了与编码柠檬酸盐通透酶的citP、编码蛋白酶的prtP以及分别编码乳酸链球菌素A或乳酸链球菌素Z的结构基因nisA或nisZ相关序列的存在。通过这些方法，有可能从各种环境来源，如土壤、废水和牛的皮肤中分离出乳球菌。分离得到的乳酸乳球菌菌株在许多特性上与工业发酵剂培养物中发现的菌株不同，例如水解精氨酸的能力或缺乏与citP相关的序列。结果表明，尽管存在自然生态位，但大多数工业生产的乳球菌在乳制品环境之外无法存活。然而，从这些生态位中可能分离出有潜力开发成新型发酵剂培养物的菌株。
