Department of Microbiology, University College Cork, Cork, Ireland.
J Dairy Sci. 2013 Aug;96(8):4945-57. doi: 10.3168/jds.2013-6748. Epub 2013 Jun 13.
This study reports on the identification and characterization of bacteriophages isolated from cheese-production facilities that use undefined, mixed starter cultures. Phage screening was carried out on whey samples isolated from 3 factories, 2 utilizing one particular undefined starter mixture and 1 utilizing another undefined starter mixture. Phage screening was carried out using 40 strains isolated from the 2 mixed starter cultures, and phages were profiled using host range, electron microscopy, multiplex PCR, and DNA restriction analysis. Twenty distinct lactococcal phages were identified based on host range and DNA restriction profiles, all belonging to the 936-type phage species. Nineteen of these phages were found to be able to infect both recognized subspecies of Lactococcus lactis. Restriction of phage DNA isolated using a newly developed guanidinium thiocyanate disruption method showed that the genomes of the 20 isolated phages were between 26 and 31 kb in size. It is evident from this study that the use of mixed starters creates an ideal environment for the proliferation of different phages with slightly varying host ranges. Furthermore, in this environment, members of the 936-type phage species clearly dominated the phage population.
本研究报告了从使用未定义、混合起始培养物的奶酪生产设施中分离和鉴定噬菌体的情况。在 3 家工厂的乳清样本中进行了噬菌体筛选，其中 2 家使用了一种特定的未定义起始混合物，1 家使用了另一种未定义起始混合物。使用从 2 种混合起始培养物中分离出的 40 株菌进行了噬菌体筛选，并通过宿主范围、电子显微镜、多重 PCR 和 DNA 限制分析对噬菌体进行了分析。根据宿主范围和 DNA 限制图谱，确定了 20 种不同的乳球菌噬菌体，均属于 936 型噬菌体。其中 19 种噬菌体被发现能够感染已识别的乳球菌 lactis 亚种。使用新开发的胍硫氰酸破坏法对分离出的噬菌体 DNA 进行限制显示，20 种分离出的噬菌体的基因组大小在 26 到 31kb 之间。从这项研究中可以明显看出，使用混合起始物为具有略微不同宿主范围的不同噬菌体的增殖创造了理想的环境。此外，在这种环境中，936 型噬菌体明显占据了噬菌体种群的主导地位。
