Probiotics are increasingly popular, currently. Probiotics have been described with the ability to treat many disorders of the gastrointestinal tract (GIT) such as irritable bowel syndrome (IBS) and Crohn’s disease. Types of probiotics include bacterial strains from Lactobacillus and Bifidobacterium. Probiotics can restore balance to gut microbiota by outcompeting pathogenic bacteria for nutrients and secrete antimicrobials to eliminate these bacterial pathogens. However, the viability of most advertised probiotics lose their potency due to being freeze dried into powders during storage or for consuming. Many probiotics become ineffective and produce lower CFUs while traversing through the gastric acids of the digestive system. For these reasons, this study sought to enhance the antimicrobial response of a highly potent probiotic known as Bacillus subtilis. B. subtilis has been used to treat many disorders of the gut and secrete many antimicrobials lethal for pathogenic microbes. B. subtilis was genetically modified to express CRISPR-Cas9 nuclease deletion of the accA gene (ΔB.subtilis mutants), which inhibits expression of an essential accA gene a part of the fatty acid synthesis (FAS) metabolic pathway. The CRISPR-Cas9-accA ΔB.subtilis mutants were co-cultured with V. harveyi and E. Coli. Bacterial growth, biofilm formation, antimicrobial activity, and antibiotic resistance were quantified. It was found that ΔB.subtilis mutants co-cultured with V. harveyi and E. Coli lessened bacterial growth, amplified biofilm with V. harveyi, reduced biofilm formation of E. Coli, the co-cultures with the mutants lacked antimicrobial activity, and increased the antibiotic resistance of V. harveyi and E. Coli. It can be concluded that there is an immense potential for using genetically engineered probiotic strains to enhance the antimicrobial activity of B. subtilis, which can amplify the reduction of pathogenic bacteria. However, the safety and frugality of using B. subtilis as a probiotic requires further consideration.

中文翻译：

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量化 CRISPR-Cas9-accA 修饰 ΔB 的抗菌活性。针对 V. harveyi 和 E. Coli 的 subtilis 突变体

目前，益生菌越来越受欢迎。益生菌已被描述为能够治疗许多胃肠道 (GIT) 疾病，例如肠易激综合征 (IBS) 和克罗恩病。益生菌的类型包括来自乳杆菌和双歧杆菌的菌株. 益生菌可以通过与病原菌竞争营养并分泌抗菌素来消除这些细菌病原体，从而恢复肠道微生物群的平衡。然而，由于在储存或食用过程中被冷冻干燥成粉末，大多数宣传的益生菌失去了它们的活力。许多益生菌在穿过消化系统的胃酸时变得无效并产生较低的 CFU。由于这些原因，本研究试图增强一种称为枯草芽孢杆菌的高效益生菌的抗菌反应。B. subtilis已被用于治疗许多肠道疾病并分泌许多对病原微生物致命的抗微生物剂。枯草芽孢杆菌经过基因改造以表达 CRISPR-Cas9 核酸酶缺失accA基因（Δ B.subtilis突变体），它抑制必需的accA基因的表达，该基因是脂肪酸合成 (FAS) 代谢途径的一部分。CRISPR-Cas9-accA ΔB.subtilis突变体与V. harveyi和E. Coli共培养。对细菌生长、生物膜形成、抗菌活性和抗生素耐药性进行了量化。发现ΔB.subtilis突变体与V. harveyi和E. Coli共培养减少了细菌生长，放大了与V. harveyi 的生物膜，减少了E. Coli 的生物膜形成，与突变体的共培养物缺乏抗菌活性，并增加了哈维伊氏菌和大肠杆菌的抗生素抗性。可以得出结论，使用基因工程益生菌菌株来增强枯草芽孢杆菌的抗菌活性具有巨大的潜力，这可以放大病原菌的减少。然而，使用枯草芽孢杆菌作为益生菌的安全性和节俭性需要进一步考虑。