Bacteriophages and plasmids in Streptococcus thermophilus

嗜热链球菌中的噬菌体和质粒

• 批准号: RGPIN-2019-06705
• 负责人: Moineau, Sylvain
• 金额: $ 8.38万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=693003
• 关键词: Bacteriophages; plasmids; Streptococcus; thermophilus

The dairy industry is a significant part of our heritage and our economy. It is the third largest sector of the Canadian agri-food economy behind grains and red meats. In 2016 (last year for which data are available), dairy farming generated $6.2 billion and manufactured shipments of milk and dairy products equaled $17.7 billion. Overall, the dairy industry accounted for 15.8% of all processing sales in our nation's food and beverage sector. The dairy workforce includes 18,805 dairy farm operators while the manufacturing sector includes 22,904 jobs which are spread into the 471 Canadian dairy factories. Canada produces more than 1,050 cheeses that are listed in the Canadian Cheese Directory. Last year, Mozzarella and pizza cheeses were produced at a record level in Canada (> 148,000 kg, +2.0% from the previous year). A record level was also observed with the production of speciality cheeses (> 163,000 kg, +5.5% from the previous year). There is no indication that this production trend will change. However, our dairy industry faces intense competition in national and international markets and must deliver high-quality products. ******Cheese manufacture requires the inoculation of milk with carefully selected bacterial cells (starter culture) to properly control the fermentation and to obtain high-quality products. The starter culture is a combination of lactic acid-producing bacteria, from which Streptococcus thermophilus is one of the most important species. It is well documented that increased productivity within existing manufacturing facilities will lead to milk fermentation failures due to bacterial viruses (phages) that destroy the starter cultures. A shut down of production may even be required to thoroughly clean up the facilities. This natural phenomenon leads to low quality products and economic losses. Thus, constant phage monitoring and stringent application of phage control measures are indispensable. One of the key measures is to use phage-resistant bacterial cultures. CRISPR-Cas systems are by far the most important phage defense mechanisms in S. thermophilus and CRISPR-phage-resistant S. thermophilus strains are now used worldwide. However, phages are evolving and they have found ways to bypass the CRISPR-Cas defense systems. This fundamental research program on S. thermophilus will focus on three areas: 1) Phage biology, 2) Phage resistance, and 3) Plasmid biology. This grant will also train several students in various areas of biological sciences such as microbiology, virology, biochemistry, molecular biology, bioinformatics, and food sciences.******This ambitious and state-of-the-art program will lead to the most comprehensive analysis of phage-host interactions in a Gram-positive bacterium. This research will provide fundamental knowledge to our Canadian dairy industry to give them a competitive edge. This knowledge will also be applicable to other bacterial strains susceptible to phage attack in industrial fermentations.

乳制品行业是我们遗产和经济的重要组成部分。它是加拿大农业用品经济的第三大领域，仅次于谷物和红肉。 2016年（去年可获得的数据），奶牛场产生了62亿美元，制造的牛奶和乳制品货物等于177亿美元。总体而言，乳制品行业占我们国家食品和饮料部门所有加工销售的15.8％。乳制品劳动力包括18,805家奶牛场运营商，而制造业则包括22,904个工作岗位，这些工作被分配到471个加拿大乳品工厂中。加拿大生产超过1,050多个奶酪，这些奶酪在加拿大奶酪目录中列出。去年，马苏里拉奶酪和披萨奶酪是在加拿大创纪录的（> 148,000公斤，比上一年 +2.0％）生产。生产特种奶酪（> 163,000公斤， +上一年 +5.5％）也观察到了创纪录的水平。没有迹象表明这种生产趋势会改变。但是，我们的乳制品行业在国家和国际市场上面临激烈的竞争，必须提供高质量的产品。 ******奶酪生产需要用精心选择的细菌细胞（开胃培养）接种牛奶，以正确控制发酵并获得高质量的产品。起动培养物是产生乳酸的细菌的结合，嗜热链球菌是最重要的物种之一。有充分的文献证明，现有制造设施内的生产率提高将导致牛奶发酵失败，这会破坏开胃植物的细菌病毒（噬菌体）。甚至可能需要关闭生产才能彻底清理设施。这种自然现象会导致低质量的产品和经济损失。因此，持续的噬菌体监测和噬菌体控制措施的严格应用是必不可少的。关键措施之一是使用耐噬菌体的细菌培养物。 CRISPR-CAS系统是迄今为止最重要的噬菌体防御机制，在全球范围内使用了嗜热链球菌和耐嗜热链球菌菌株。但是，噬菌体正在发展，他们找到了绕过CRISPR-CAS防御系统的方法。有关嗜热链球菌的基本研究计划将重点放在三个领域：1）噬菌体生物学，2）噬菌体耐药性和3）质粒生物学。该赠款还将在生物科学领域的各个领域进行培训，例如微生物学，病毒学，生物化学，分子生物学，生物信息学和食品科学。这项研究将为我们的加拿大乳制品行业提供基本知识，以使他们具有竞争优势。这些知识也将适用于在工业发酵中容易受到噬菌体攻击的其他细菌菌株。