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 放线菌聚集菌 (Aa) 和其他细菌附着在生物和非生物表面， 产生胞外多糖，用于将细菌细胞固定在这些定植表面上 形成生物膜基质。 Aa产生的胞外多糖是N-乙酰基-D-的均聚物 具有 b-1,6-连接单元的葡萄糖胺 (GlcNAc)（缩写为 PGA）。在生物膜生长过程中，要克服 与人口过剩相关的饥饿，细胞必须从表面分散到远端表面 进一步殖民。分散素 B 的水解作用促进了 Aa 释放细胞的这种运动 (DspB)，一种由 Aa 产生的酶，可释放陷入生物膜基质的细胞。产品 PGA 水解的 GlcNAc 存在于成熟生物膜周围，可以成为 Aa 和 其他邻近的细菌。在许多细菌共生的多物种生物膜中，Aa 通过以下方式获取营养： 将自身定位在共生细菌戈登链球菌 (Sg) 附近。在这种情况下，Aa 可以利用 Sg 产生的乳酸是其生长的首选碳源。为了维持Sg的存在 在其附近，往复运动中，Aa 通过 DspB 的作用向邻近的 Sg 提供 GlcNAc 职业高尔夫球协会。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物质而生存。 合作，其中双方都具有在利基市场中持续殖民的优势。需要注意的是 生物膜有利于细菌之间的互利或合作交叉喂养 (2)。我们的假设是 1) PGA 衍生的 GlcNAc，而非外源 GlcNAc，对于 Aa 在细胞中的存活和定植非常重要。 生物膜和与 Sg 的代谢交叉喂养关系； 2) Aa 的毒力需要 DspB。我们将 通过以下具体目标来检验这些假设： 具体目标 1：a) 证明 DspB 对于 Aa 在生物膜生长模式中的存活至关重要。 b) 证明 DspB 对于维持交叉喂养关系至关重要，并且 与Sg合作进行营养交换。 具体目标 2：表征 DspB 在 Aa 在口腔中的定植和毒力中的作用。