Evaluating Antimicrobial Compounds from Coral-Associated Pseudovibrio Bacteria

说明(申请人提供)：由于微生物对常规抗生素抗药性的增加和新药(1，2)的不足，寻找新的抗生素与人类健康直接相关。珊瑚礁是最具生物多样性的海洋生态系统，也是新型抗生素的来源，但由于疾病、气候变化和污染，珊瑚礁受到威胁(3)。由于海洋细菌可以产生与陆地细菌在化学上不同的化合物(4)，因此必须对珊瑚中未知的微生物多样性及其潜在的抗生素进行分类和表征。这项工作的主要目标是表征与珊瑚相关的海洋细菌中的抗生素，并研究抗生素对病原体生理的功能作用。第一个目标是确定从美洲鬼臼表面粘多糖层(SML)分离的细菌的抗菌活性，SML是一个丰富和多样化的微生物群落的富碳栖息地(5)。SML选择具有抗菌活性的共生菌，该共生菌可以通过检测病原微生物来保护珊瑚宿主(6，7)。我们将使用琼脂覆盖抗菌素试验来确定美洲葡萄球菌SML相关细菌对七种与人类和珊瑚相关的微生物的抗菌素生产情况。第二个目标专门针对NIAID/NIH的药物发现任务，从广谱抗菌珊瑚分离株中鉴定和表征抗菌化合物，并利用分子技术调查其遗传生物活性潜力。抗生素化合物(S)将通过层析(如高效液相色谱)、质谱学(如LC-MS)和波谱(核磁共振)技术进行纯化和结构表征。分子技术将被用来确定已知产生生物活性化合物的基因的存在。第三个目标将通过与抗菌珊瑚分离物共培养的代谢谱特征来分析抗生素对珊瑚病原体的可能作用机制。我们将利用代谢组学来分析弧菌病原体在抗菌珊瑚分离物存在时细胞内的变化，重点是利用核磁共振分析代谢变化(例如DNA、RNA、蛋白质合成)。相关性--《世界卫生报告》将微生物抗生素耐药性列为对公众健康的主要威胁，由于新抗生素药物的开发研究减少，这一点进一步加强(8)。本项目旨在通过表征潜在的新型抗生素(S)及其对微生物病原体生理的作用来满足这一需求。

DESCRIPTION (provided by applicant): The search for novel antibiotics is of direct human health relevance because of the increase in microbial resistance to conventional antibiotics and a deficit in new drugs (1, 2). Coral reefs are the most biodiverse of marine ecosystems and a source of novel antibiotics, but they are threatened due to disease, climate change, and pollution (3). Since marine bacteria can produce compounds that are chemically distinct from their terrestrial counterparts (4), it is imperative to catalog and characterize the unknown microbial diversity in corals and their potential antibiotics. The main objectives of this work are to characterize antibiotics from marine bacteria associated with a coral, and to study the functional role of the antibiotic insult on a pathogen's physiology. The first aim will ascertain the antimicrobial activity of bacteria isolated from Pseudopterogorgia americana surface mucopolysaccharide layer (SML), which is a carbon-rich habitat for an abundant and diverse microbial community (5). The SML selects for symbiotic bacteria with antimicrobial activity that may protect the coral host by detemng pathogenic microorganisms (6, 7). We will use an agar- overlay antimicrobial assay to determine the antimicrobial production of P. americana's SML-associated bacteria against seven microorganisms relevant to human and corals. The second aim specifically targets NIAID/NIH's mission for drug discovery by identifying and characterizing antimicrobial compounds from a broad-spectrum antimicrobial coral isolate, and surveying its genetic bioactive potential with molecular techniques. Antibiotic compound(s) will be purified and structurally characterized using chromatographic (e.g., HPLC), mass spectrometric (e.g., LC-MS), and spectroscopic (NMR) techniques. Molecular techniques will be performed to determine presence of genes known to produce bioactive compounds. The third aim will analyze a possible mechanism of antibiotic action against a coral pathogen through metabolic profile characterization of its co-culture with the antimicrobial coral isolate. We will utilize metabolomics to analyze the intracellular changes of a Vibrio pathogen when in presence of an antimicrobial coral isolate, focusing on metabolic changes (e.g., DNA, RNA, protein synthesis) using NMR analysis. Relevance- The World Health Report categorized microbial antibiotic resistance as a major threat to public health, which is augmented due to the diminished developmental research for new antibiotic drugs (8). This project seeks to meet this demand by characterizing potentially novel antibiotic(s) and their function on a microbial pathogen's physiology.