Mining a collection of soil amoebae for antibacteria agents

描述(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一种手段，科学家们利用这一事实发现了当今用于治疗疾病的绝大多数药物。盘基网柄菌是已知基因组中最大的聚酮合成酶(PKS)库。此外，这种生物体中的某些类型的PKSS与其他具有酶活性的蛋白结构域融合在一起。这种独特的杂交排列非常有效地合成了参与黏液霉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，因为临床上使用的大多数抗生素都是来自土壤微生物的聚酮类化合物--然而，阿米巴在这方面还没有得到检查。我们将开始筛选大量土壤传播的阿米巴变形虫，用于生产抗生素。已故的肯尼斯·拉珀博士是研究社会阿米巴的生态学和系统学的权威，他积累了这一资源。Raper档案馆是一个多样化的社会土壤传播的阿米巴虫的集合，代表了5个不同的属，17个不同的物种和1000多个独特的分离物。在这个项目中，将在固体或液体介质中培养双鞭毛虫和它们的细菌猎物的共培养物，并使用一组已知的病原体对这些共培养物的上清进行抗菌活性筛选。太阳能电池板还将在液体和固体介质中生长。将进行生物检测，以确定含有抗菌活性的上清液。通过使用截留分子量(5x103)的膜过滤器，我们将评估抗生素的功能是蛋白质依赖的还是小分子依赖的。纯化程序将根据推测的抗生素性质而设计。我们的R21项目将通过指导经过验证的抗生素发现战略来瞄准一种新的和有希望的微生物次级代谢物来源--真核土壤栖息的阿米巴，从而重振制药NP的研究。在短期内，这项研究将提高我们对甲藻功能基因组学的科学知识。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。 与公共卫生相关：日益严重的抗生素耐药性问题正在产生对大力开展药物发现研究的需求。大多数临床抗生素来自土壤细菌的筛选，这些细菌以产生有价值的代谢物而闻名，但越来越多地产生以前发现的抗生素。在这个抗生素发现项目中，我们将筛选一组尚未开发的微生物，它们的生态和生化特征与昨天多产的微生物相似：居住在土壤中的真核社会阿米巴。

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.