Role of Dispersin B in the colonization and virulence of Aggregatibacter actinomycetemcomitans

分散素 B 在放线菌聚集菌定植和毒力中的作用

• 批准号: 9525196
• 负责人: NARAYANAN RAMASUBBU
• 金额: $ 23.85万
• 依托单位: RBHS-SCHOOL OF DENTAL MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9525196
• 关键词: Actinobacillus actinomycetemcomitans; Adolescent; Adult; Affect; African American; Alveolar Bone Loss; Animals; Bacteria; Bacterial Infections; Carbon; Cells; Clinical; Coculture Techniques; Control Groups; Diagnosis; Disease; Distal; Ecosystem; Elderly; Ensure; Environment; Enzymes; Epidemic; Etiology; Exhibits; Famines; Food; Gene Expression Regulation; Genes; Genetic Transcription; Glucosamine; Goals; Growth; Habitats; Habits; Human; Hydrolysis; Immobilization; Immune response; In Vitro; Individual; Laboratories; Life Style; Link; Location; Metabolic; Methods; Microbial Biofilms; Minority; Modeling; Mouth Diseases; Movement; Nutrient; Nutritional; Oral cavity; Periodontitis; Play; Polymers; Polysaccharides; Population; Positioning Attribute; Rattus; Reporting; Role; Seeds; Serotyping; Site; Source; Starvation; Streptococcus gordonii; Surface; Surgeon; Surveys; Testing; Tissue-Specific Gene Expression; Up-Regulation; Virulence; adolescent patient; bone loss; commensal bacteria; depolymerization; experimental study; extracellular; feeding; microorganism; mutant; nutrition; operation; overpopulation; transcriptome sequencing; virtual

Abs tract Aggregatibacter actinomycetemcomitans (Aa) and other bacteria attach to biotic and abiotic surfaces and produce exopolysaccharides, which are used to immobilize the bacterial cells on these colonized surfaces forming a biofilm matrix. The exopolysaccharide produced by Aa is a homopolymer of N-acetyl-D- glucosamine (GlcNAc) with b-1,6-linked units (abbreviated as PGA). During biofilm growth, to overcome starvation associated with overpopulation, cells must disperse from a surface to move to distal surfaces to colonize further. This movement of released cells of Aa is facilitated by the hydrolytic action of Dispersin B (DspB), an enzyme produced by Aa, which releases cells that are enmeshed in the biofilm matrix. The product of PGA hydrolysis, GlcNAc, is present around the mature biofilm and could become a nutrient for Aa and other neighboring bacteria. In a multispecies biofilm where many bacteria co-habitat, Aa gains nutrients by positioning itself near the commensal bacterium, Streptococcus gordonii (Sg). In this scenario, Aa can utilize the lactate produced by Sg, a preferred carbon source, for its growth. In order to maintain the presence of Sg in its vicinity, in reciprocation, Aa supplies the neighboring Sg with GlcNAc through the action of DspB on PGA. Since GlcNAc is a preferred carbon source for Sg, both bacteria can survive by entering into a nutritional co-operation wherein both have an advantage for persistent colonization in the niche. It should be noted that mutualistic or cooperative cross-feeding between bacteria is favored in biofilms (2). Our hypothesis is that 1) PGA-derived GlcNAc, not exogenous GlcNAc, is important for the survival and colonization of Aa in the biofilm and metabolic cross-feeding relationship with Sg; 2) DspB is required for the virulence of Aa. We will test these hypotheses with the following Specific Aims: Specific Aim 1: a) Demonstrate that DspB is essential for the survival of Aa in a biofilm mode of growth. b) Demonstrate that DspB is essential to maintain the cross-feeding relationship and cooperative nutrient exchange with Sg. Specific Aim 2: Characterize the role of DspB in the colonization and virulence of Aa in the oral cavity.

抽象的 聚集的放线菌菌（AA）和其他细菌附着于生物和非生物表面以及 产生外多糖，用于将细菌细胞固定在这些定殖表面上 形成生物膜基质。 AA产生的外多糖是N-乙酰基-D-的均聚物 葡萄糖胺（GLCNAC），具有B-1,6连接单元（缩写为PGA）。在生物膜生长期间要克服 与人口过多相关的饥饿，细胞必须从表面分散到远端表面到远端 进一步定居。释放的AA细胞的这种运动通过分散的水解作用来促进 （DSPB），一种由AA产生的酶，该酶释放出嵌入生物膜基质中的细胞。产品 成熟生物膜周围存在PGA水解，GlcNAC，可能成为AA和AA的营养素 其他邻近细菌。在多种细菌共同使用的多物种生物膜中，AA获得营养 将自己定位在共生细菌链球菌（SG）附近。在这种情况下，AA可以使用 SG（首选碳源生长）生产的乳酸。为了维持SG的存在 在附近，AA通过DSPB的作用向附近的SG提供了glcNAC PGA。由于GlcNAC是SG的首选碳源，因此两种细菌都可以通过进入营养而生存 合作，其中两者都有优势在利基市场中持续定殖。应该指出的是 在生物膜中有利于细菌之间的相互主义或合作交叉进食（2）。我们的假设是1） PGA衍生的GlcNAC而非外源性GlcNAC对于AA的存活和定殖至关重要 与SG的生物膜和代谢交叉喂养关系； 2）DSPB是AA的毒力所必需的。我们将 以以下特定目的测试这些假设： 具体目标1：a）证明DSPB对于在生物膜生长模式下AA的生存至关重要。 b）证明DSPB对于维持交叉喂养关系至关重要 与SG的合作营养交换。 具体目标2：表征DSPB在AA在口腔中的定殖和毒力中的作用。