The Tape Measure Protein Is Involved in the Heat Stability of Lactococcus lactis Phages
The Tape Measure Protein Is Involved in the Heat Stability of Lactococcus lactis Phages
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DOI：
10.1128/aem.02082-17
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发表时间：
2018-02-01
影响因子：
4.4
通讯作者：
Moineau, Sylvain
中科院分区：
文献类型：
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作者：
Geagea, Hany;Labrie, Simon J.;Moineau, Sylvain
致病性乳球菌芽孢杆菌仍然是牛奶发酵过程的主要风险，因为它们可能导致速度减慢和低质量的发酵乳制品，特别是奶酪。工业上使用的一些噬菌体控制策略依赖于热处理。近年来发现了一些具有高度耐热性的乳酸乳球菌。为了鉴定负责乳球菌属细菌耐热性的遗传决定因子，我们使用了强毒噬菌体CB 14（属于乳酸乳球菌936噬菌体组[现在的Sk1virus]）来选择具有增加的热稳定性的噬菌体突变体。通过将噬菌体CB 14连续低温和高温处理，我们能够选择两种具有增加的热稳定性的CB 14衍生物。它们的基因组测序揭示了与野生型噬菌体CB 14相同的核苷酸序列，除了在每个噬菌体突变体的编码卷尺蛋白（TMP）的基因中的相同大小的缺失（120 bp），但在不同的位置。将这些突变体的TMP蛋白序列与其它野生型L.具有广泛多样性的热稳定性。比较分析表明，同样的核苷酸缺失似乎也发生在编码高度耐热性乳球菌P1532和P680的TMP的基因中。我们建议，TMP是，在一定程度上，负责的热稳定性的高度占主导地位的乳球菌的SK 1病毒group.IMPORTANCE的毒力乳球菌仍然是牛奶发酵的主要风险，因为它们可能会导致减速和低质量的发酵乳制品。热处理是控制干酪副产品中这些有毒有害物质最常用的方法之一。最近，一些乳酸乳球菌，Sk1病毒组的成员，已经出现了高热稳定性。据我们所知，在乳球菌中负责这种耐热性的遗传决定因素是未知的。需要更好地了解这些新出现的有毒乳球菌的热稳定性，以改善工业控制策略。在这项工作中，我们报告的鉴定噬菌体结构蛋白，参与了一个有毒的Sk1病毒噬菌体的热稳定性。确定这种热稳定性的遗传决定因素是理解这组热稳定性基因出现的第一步。
Virulent lactococcal phages are still a major risk for milk fermentation processes as they may lead to slowdowns and low-quality fermented dairy products, particularly cheeses. Some of the phage control strategies used by the industry rely on heat treatments. Recently, a few Lactococcus lactis phages were found to be highly thermoresistant. To identify the genetic determinant(s) responsible for the thermal resistance of lactococcal phages, we used the virulent phage CB14 (of the Lactococcus lactis 936 [ now Sk1virus] phage group) to select for phage mutants with increased heat stability. By treating phage CB14 to successive low and high temperatures, we were able to select two CB14 derivatives with increased heat stability. Sequencing of their genome revealed the same nucleotide sequences as the wild-type phage CB14, except for a same-sized deletion (120 bp) in the gene coding for the tape measure protein (TMP)of each phage mutant, but at a different position. The TMP protein sequences of these mutant phages were compared with their homologues in other wild-type L. lactis phages with a wide diversity in heat stability. Comparative analysis showed that the same nucleotide deletion appears to have also occurred in the gene coding for the TMP of highly thermo-resistant lactococcal phages P1532 and P680. We propose that the TMP is, in part, responsible for the heat stability of the highly predominant lactococcal phages of the Sk1virus group.IMPORTANCE Virulent lactococcal phages still represent a major risk for milk fermentation as they may lead to slowdowns and low-quality fermented dairy products. Heat treatment is one of the most commonly used methods to control these virulent phages in cheese by-products. Recently, a few Lactococcus lactis phages, members of the Sk1virus group, have emerged with high thermal stability. To our knowledge, the genetic determinant(s) responsible for this thermal resistance in lactococcal phages is unknown. A better understanding of the thermal stability of these emerging virulent lactococcal phages is needed to improve industrial control strategies. In this work, we report the identification of a phage structural protein that is involved in the heat stability of a virulent Sk1virus phage. Identifying such a genetic determinant for heat stability is a first step in understanding the emergence of this group of thermostable phages.