Department of Food Science and Technology, Federal Institute of Southeast of Minas Gerais, 36180-000 Rio Pomba, MG, Brazil.
Food Research Center, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, 05508-000 São Paulo, SP, Brazil.
Biomed Res Int. 2018 Oct 22;2018:2723157. doi: 10.1155/2018/2723157. eCollection 2018.
The 16S rDNA of six psychrotrophic Enterobacteriaceae isolated from cold raw milk were sequenced and the isolate 039 was identified as sp., isolates 059, 068, and 071 were identified as , 067 was identified as sp., and 099 was identified as . They presented different spoilage potentials in milk with 099 being the most deteriorative. Only sp. 039 was not able to induce the quorum sensing monitor strains of acyl homoserine lactones (AHLs). The gene, which encodes the AHL synthase in , was identified in the isolates 059, 067, 068, and 071. After initial sequencing characterization and cloning, this gene showed its function by the heterologous synthesis of N-hexanoyl-DL-homoserine lactone and N-3-oxohexanoyl-L-homoserine lactone in . In addition to producing AHLs, 099 produced AI-2 in higher level than the assay's positive control BB120. Therefore, Enterobacteriaceae strains isolated from cooled raw milk produce a rich array of signaling molecules that may influence bacterial traits in the milk environment.
从冷藏生牛乳中分离到的 6 株嗜冷肠杆菌科的 16S rDNA 序列已被测序，其中菌株 039 被鉴定为 sp.，菌株 059、068 和 071 被鉴定为 ，菌株 067 被鉴定为 sp.，而菌株 099 被鉴定为 。它们在牛奶中有不同的腐败潜力，其中 099 是最具破坏性的。只有 sp. 039 不能诱导群体感应监测菌株的酰基高丝氨酸内酯 (AHLs)。在菌株 059、067、068 和 071 中发现了编码 AHL 合酶的 基因。在经过初始测序特征分析和克隆后，该基因通过在 中异源合成 N-己酰基-DL-高丝氨酸内酯和 N-3-氧代己酰基-L-高丝氨酸内酯证明了其功能。除了产生 AHLs 外，099 产生的 AI-2 水平高于阳性对照 BB120。因此，从冷却生牛乳中分离出的肠杆菌科菌株产生了丰富的信号分子，这些信号分子可能会影响牛奶环境中的细菌特性。
