BcpAIOB-Mediated CDI and Biofilm Formation in Burkholderia pseudomallei

描述（由申请人提供）：假性伯克霍尔德菌是一种可移动的革兰氏阴性环境腐殖质菌，是一种新出现的传染病问题，也是以前被CDC武器化的一级选择剂。它在人类中引起类鼻疽，在急性形式下，如果不治疗，可以在几天内致命。虽然是东南亚和澳大利亚北部的地方病，但有证据表明假假芽孢杆菌正在超越既定边界传播。缺乏疫苗和缺乏快速诊断测试，再加上该细菌的感染剂量低和固有的抗生素耐药性，强调需要开发新的治疗方法和新战略，以消除受污染环境中的假假芽孢杆菌，这是发生向人类传播的唯一宿主。接触依赖性生长抑制（contact - dependent Growth Inhibition， CDI）是细菌在细胞与细胞接触时，利用暴露在表面的外蛋白的有毒c端抑制邻近细菌生长的一种现象。如果存在于细胞质中，免疫蛋白与有毒多肽结合，阻断其催化活性，防止细胞死亡。CDI系统外蛋白的毒性c端和免疫蛋白具有多态性，免疫蛋白以等位基因特异性的方式保护CDI。有人认为，这种多态性允许细菌使用CDI系统来区分自我和非自我，作为微生物群落亲缘选择的机制，但这一假设尚未得到验证。不同的CDI系统是否有等级的效力，以及拥有多个CDI系统是否有利，也没有经过测试。我们提出实验来确定假芽孢杆菌中的bcpAIOB基因是否如预测的那样编码介导假芽孢杆菌细菌间竞争和生物膜形成的蛋白质。我们将确定不同的bcpAIOB等位基因编码的蛋白质是否具有不同的效力，以及拥有多个等位基因是否具有竞争优势。我们还将确定是否发生种间CDI，是否可以设计泰国伯克霍尔德菌（与假芽孢杆菌生活在同一生态位的非病原体）产生多个CDI系统，以及该菌株是否能够与假芽孢杆菌竞争并阻止或破坏假芽孢杆菌的生物膜。我们的研究结果将为CDI系统的应用奠定基础

DESCRIPTION (provided by applicant): Burkholderia pseudomallei, a motile, Gram-negative, environmental saprotroph, is an emerging infectious disease problem and a previously-weaponinzed CDC Tier 1 select agent. It causes melioidosis in humans, which, in its acute form, can be fatal within days if untreated. Although endemic to southeast Asia and northern Australia, there is evidence that B. pseudomallei is spreading beyond established boundaries. Lack of a vaccine and lack of rapid diagnostic tests, together with the bacterium's low infectious dose and intrinsic antibiotic resistance, underscore the need to develop new therapeutics and new strategies for eliminating B. pseudomallei from contaminated environments, the only reservoir from which transmission to humans occurs. Contact-Dependent Growth Inhibition (CDI) is a phenomenon in which bacteria use the toxic C-terminus of a large surface-exposed exoprotein to inhibit the growth of neighboring bacteria upon cell-cell contact. If present in the cytoplasm, immunity proteins bind to the toxic polypeptides, blocking their catalytic activity and preventing cell death. The toxic C-termini of CDI system exoproteins and the immunity proteins are polymorphic and immunity proteins protect against CDI in an allele-specific manner. It has been suggested that this polymorphism allows bacteria to use CDI systems to discriminate self from non-self as a mechanism for kin selection in microbiological communities, but this hypothesis has not been tested. Whether there is a hierarchy of potencies of different CDI systems and whether the possession of multiple CDI systems is advantageous have also not been tested. We propose experiments to determine if bcpAIOB genes in B. pseudomallei do, as predicted, encode proteins that mediate interbacterial competition and biofilm formation in B. pseudomallei. We will determine if different bcpAIOB alleles encode proteins with different potencies, and if possession of multiple alleles confers a competitive advantage. We will also determine if inter-species CDI occurs and if Burkholderia thailandensis, a non-pathogen that lives in the same ecological niche as B. pseudomallei, can be engineered to produce multiple CDI systems and if this strain can out-compete B. pseudomallei and prevent or destroy B. pseudomallei biofilms. Our results will form the foundation for the exploitation of CDI systems for use as decontaminants and, potentially, therapeutics.