Duplessis Martin, Lévesque Céline M, Moineau Sylvain
Département de Biochimie et de Microbiologie, Faculté des Sciences et de Génie, Groupe de Recherche en Ecologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, Quebec, Canada G1K 7P4.
Appl Environ Microbiol. 2006 Apr;72(4):3036-41. doi: 10.1128/AEM.72.4.3036-3041.2006.
To investigate phage-host interactions in Streptococcus thermophilus, a phage-resistant derivative (SMQ-301R) was obtained by challenging a Tn917 library of phage-sensitive strain S. thermophilus SMQ-301 with virulent phage DT1. Mutants of phages DT1 and MD2 capable of infecting SMQ-301 and SMQ-301R were isolated at a frequency of 10(-6). Four host range phage mutants were analyzed further and compared to the two wild-type phages. Altogether, three genes (orf15, orf17, and orf18) contained point mutations leading to amino acid substitutions and were responsible for the expanded host range. These three proteins were also identified in both phages by N-terminal sequencing and/or matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The results suggest that at least three phage structural proteins may be involved in phage-host interactions in S. thermophilus.
为了研究嗜热链球菌中的噬菌体-宿主相互作用，通过用烈性噬菌体DT1挑战噬菌体敏感菌株嗜热链球菌SMQ-301的Tn917文库，获得了一种噬菌体抗性衍生物（SMQ-301R）。能够感染SMQ-301和SMQ-301R的噬菌体DT1和MD2的突变体以10^(-6)的频率被分离出来。对四个宿主范围噬菌体突变体进行了进一步分析，并与两种野生型噬菌体进行了比较。总共，三个基因（orf15、orf17和orf18）发生了导致氨基酸替换的点突变，并导致宿主范围扩大。通过N端测序和/或基质辅助激光解吸电离飞行时间质谱法在两种噬菌体中也鉴定出了这三种蛋白质。结果表明，至少三种噬菌体结构蛋白可能参与嗜热链球菌中的噬菌体-宿主相互作用。
