Mining a collection of soil amoebae for antibacteria agents

描述（由申请人提供）：生物体使用化学物质作为与周围环境相互作用的手段，科学家已经利用这一事实发现了今天用于治疗疾病的绝大多数药物。盘状盘基网柱体（Dictyostelium disideum）具有已知基因组中最大的聚酮合成酶（PKS）酶库。此外，在这种生物体中，某些类型的PKSs融合到其他酶活性蛋白结构域。这种独特的杂交排列可以高效地合成参与黏菌细胞分化的聚酮分子。这对传染病的治疗具有潜在的影响，因为临床使用的大多数常见抗生素是从土壤传播的微生物中提取的聚酮——然而，在这方面还没有对变米虫进行研究。我们将开始筛选大量的土传变形虫档案，用于生产抗生素。已故的肯尼斯·雷珀博士是社会变形虫生态学和系统发育方面的权威，他积累了这些资源。Raper档案是一个多样化的社会土壤传播变形虫的集合，代表了五个不同的属，十七个不同的物种，超过一千种独特的分离株。在这个项目中，将在固体或液体培养基中培养盘牙甾体及其猎物细菌，并使用一组已知病原体筛选这些共培养物的上清液的抗菌活性。面板也将在液体和固体介质中生长。将进行生物测定以鉴定含有抗菌活性的上清液。通过使用具有分子量截止值（5 × 103）的膜过滤器，我们将评估抗生素功能是蛋白质还是小分子依赖。将根据推断的抗生素性质设计纯化程序。我们的R21项目将通过指导经过验证的抗生素发现策略来振兴药物NP研究，以新的和有前途的微生物次级代谢物来源为目标，真核土壤居住变形虫。在短期内，本研究将提高我们对蝶基骨类功能基因组学的科学认识。最终，我们的工作将确定急需的抗生素的先导化合物，这些化合物可能具有新的化学结构和作用机制。

DESCRIPTION (provided by applicant): Organisms use chemicals as a means of interacting with their surroundings and scientists have exploited this fact to discover the vast majority of pharmaceuticals used to treat disease today. Dictyostelium discoideum exhibits the largest repository of polyketide synthase (PKS) enzymes of all known genomes. Furthermore, some types of PKSs in this organism are fused to other enzymatically active protein domains. The unique hybrid arrangement works with great efficiency to synthesize polyketide molecules that are involved in the differentiation of slime mold cells. This has potential implications for the treatment of infectious disease because most of the common antibiotics in clinical use are polyketides derived from soil-borne microbes - however, amoebae have not been examined in this regard. We will begin screening a large archive of soil- borne amoebae for the production of antibiotics. The late Dr. Kenneth Raper, an authority on the ecology and phylogeny of social amoebae, amassed this resource. The Raper Archive is a diverse collection of social soil- borne amoebae representing five different genera, seventeen different species, and over a thousand unique isolates. In this project, co-cultures of dictyostelids and their bacterial prey will be grown in solid or liquid media and the supernatants of these co-cultures will be screened for antimicrobial activity using a panel of known pathogens. The panels will also be grown both in liquid and on solid media. Bioassays will be conducted to identify supernatants that contain antibacterial activity. By using membrane filters with a molecular weight cutoff (5 x 103), we will assess whether the antibiotic function is proteinaceous or small molecule-dependent. Purification procedures will be designed according to the inferred nature of the antibiotic. Our R21 project will reinvigorate pharmaceutical NP research by directing proven antibiotic discovery strategies to target a new and promising source of microbial secondary metabolites, eukaryotic soil-dwelling amoebae. In the short term, this research will improve our scientific knowledge of the functional genomics of dictyostelids. And ultimately, our work will identify lead compounds for much-needed antibiotics that may have novel chemical structures and mechanisms of action. PUBLIC HEALTH RELEVANCE: The growing problem of antibiotic resistance is generating a need for vigorous drug discovery research. Most clinical antibiotics come from screens of soil-dwelling bacteria, which are renowned for their production of valuable metabolites, but are increasingly yielding previously discovered antibiotics. In this antibiotic discovery project we will screen an untapped group of microorganisms with similar ecological and biochemical characteristics to the prolific producers of yesterday: the soil-dwelling, eukaryotic social amoebae.