Using CRISPR/Cas9 genome editing to facilitate antibiotic discovery in novel Streptomyces species

抗生素是我们最重要的药物之一;它们治疗一系列感染性疾病，也用于预防免疫功能低下患者的感染，如接受化疗或器官移植手术的患者。不幸的是，微生物对我们目前的抗生素产生了越来越多的耐药性，这意味着抗生素不再有效。迫切需要对耐药微生物具有活性的新抗生素。目前使用的抗生素中约有三分之二是由土壤中的细菌（如链霉菌）天然产生的化合物开发的。链霉菌被认为在环境中产生许多抗菌化合物，但在实验室中，它们通常只产生少数。这意味着如果我们能在实验室中找到开启这些“沉默”途径的方法，那么还有更多的抗菌分子有待于从链霉菌中发现。该项目将使用基因工程来开启甲酸链霉菌（Streptomyces formicae）中抗生素的生产，甲酸链霉菌是一种从Tetraponera penzigi植物蚂蚁巢穴中分离出来的新菌株。S.蚁科是一种有天赋的菌株，具有产生许多抗菌分子的潜力。到目前为止，只有一种抗生素得到了鉴定;一种新的抗生素家族，称为甲酸霉素，是耐药性微生物的有效抑制剂。通过删除负责甲酸霉素生产的基因，我们已经证明，S。蚁科开始产生以前“沉默”的化合物，包括更多对耐药微生物具有活性的新抗菌剂。在这个奖学金，我将寻求验证这些新的抗菌药物，并确定其临床潜力。我还想了解S.蚁科和为什么删除蚁科霉素途径诱导这些以前沉默的分子的生产。通过了解这些沉默的途径是如何开启的，我们可以确定是否可以在地球仪上分离的数百种其他链霉菌菌株中使用相同的方法，从而促进许多新的抗菌分子的发现。

Antibiotics are some of our most important medicines; they treat a range of infectious diseases and are also used to prevent infections in immunocompromised patients such as those undergoing chemotherapy or organ transplant surgery. Unfortunately, microorganisms are increasingly developing resistance to our current antibiotics, meaning the antibiotics no longer work as effectively. New antibiotics that have activity against resistant microorganisms are urgently needed. Around two-thirds of currently used antibiotics were developed from compounds made naturally by soil-dwelling bacteria like Streptomyces. Streptomyces are thought to produce many antimicrobial compounds in the environment, but in the lab, they only usually make a few. This means many more antimicrobial molecules remain to be discovered from Streptomyces if we can find ways to switch on these 'silent' pathways in the lab.This project will use genetic engineering to switch on the production of antibiotics in Streptomyces formicae, a new strain isolated from the nests of Tetraponera penzigi plant-ants. S. formicae is a talented strain, with the potential to produce many antimicrobial molecules. So far, only one has been characterised; a new family of antibiotics called the formicamycins which are potent inhibitors of resistant microorganisms. By deleting the genes responsible for formicamycin production, we have shown that S. formicae starts to produce previously 'silent' compounds, including more new antimicrobials that have activity against resistant microorganisms. In this fellowship, I will seek to characterise these new antimicrobials and determine their clinical potential. I also aim to understand how the antimicrobial molecules are made by S. formicae and why deletion of the formicamycin pathway induces the production of these previously silent molecules. By understanding how these silent pathways are switched on, we can determine whether the same approach could be used in the many hundreds of other Streptomyces strains isolated across the globe, facilitating the discovery of many new antimicrobial molecules.