PGA exopolysaccharide in biofilm formation and pathogenicity of Aggregatibacter a

PGA胞外多糖在聚集杆菌生物膜形成和致病性中的作用

• 批准号: 8436935
• 负责人: NARAYANAN RAMASUBBU
• 金额: $ 11.83万
• 依托单位: UNIV OF MED/DENT OF NJ-NJ DENTAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8436935
• 关键词: Acetylation; Acetylglucosamine; Actinobacillus pleuropneumoniae; Address; Affect; Bacteria; Bacterial Adhesion; Biological Models; Cells; Characteristics; Charge; Control Groups; Culture Media; DNA; Data; Deacetylase; Deacetylation; Dental Plaque; Dental caries; Disease; Enzymes; Escherichia coli; Event; Excision; Food; Genes; Gingivitis; Goals; Gram-Positive Bacteria; Health; Homologous Gene; Human; In Vitro; Individual; Knowledge; Link; Microbial Biofilms; Molecular; Mono-S; Mutate; N-terminal; Operon; Oral cavity; Organism; Pathogenicity; Periodontal Diseases; Periodontitis; Phase; Phenotype; Plasmids; Play; Polymers; Process; Proteins; Rattus; Research; Resistance; Risk; Rodent Model; Role; Serotyping; Site; Site-Directed Mutagenesis; Staging; Staphylococcus epidermidis; Surface; Testing; Tetanus Helper Peptide; Virulence; Work; Yersinia pestis; antimicrobial drug; base; bone loss; depolymerization; design; enzyme activity; in vivo; in vivo Model; insight; interest; mutant; novel; oral bacteria; oral biofilm; pathogenic bacteria; prevent; public health relevance; three dimensional structure

DESCRIPTION (provided by applicant): Aggregatibacter actinomycetemcomitans (Aa) and several pathogenic bacteria attach to abiotic surfaces and produce exopolysaccharide that immobilize the bacterial cells on these colonized surfaces. The exopolysaccharide produced by Aa is a homopolymer of ¿-1,6-linked N-acetyl-D-glucosamine (GlcNAc) units. Aa produces this exopolysaccharide (PGA) utilizing a four-gene operon homologous to the pga of Escherichia coli, hms of Yersinia pestis, and ica of Staphylococcus epidermidis. In Aa, the operon pgaABCD carries a deacetylase enzyme (EC 3.5.1.41) encoded by pgaB. Our Preliminary Data show that the enzyme PgaB has the ability to remove acetyl groups from GlcNAc of PGA. More intriguingly, we discovered that PgaB detaches preformed biofilms and inhibits biofilm formation of Aa, Actinobacillus pleuropneumoniae and S. epidermidis when added to the growth medium. We have previously shown that an enzyme dispersin B (DspB) also from Aa prevents the surface attachment of several Gram negative as well as Gram-positive bacterial species through depolymerization of PGA. Unlike DspB, the newly discovered enzyme PgaB is a deacetylase of GlcNAc residues in PGA and through deacetylation alters the charge state of PGA (enrichment of positive charges). This enzyme activity suggests that the mechanism of detachment/inhibition might be through the increased repulsive interactions on the PGA polymer. Importantly, the role of deacetylation in biofilm removal or formation is understudied in these organisms, especially in Aa. We will use PgaB from Aa as a model system to understand these processes. Our long-range goal is to understand the role of PGA in Aa pathogenicity and how the deacetylase activity of PgaB is central to this role. We will use both in vitro as well as in vivo models to tet the overall hypothesis that PGA plays a critical role in Aa virulence. Specifically, the following aims will be studied: Specific Aim 1. Demonstrate that PGA deacetylating ability of the enzyme PgaB is critical for its antibiofilm activity. Specific Aim 2a. Demonstrate that the status and degree of acetylation of PGA contributes to the biofilm formation in Aa. Specific Aim 2b. Demonstrate that the exopolysaccharide PGA contributes to Aa pathogenicity.

描述（由适用提供）：聚集的放线菌菌（AA）和几种致病细菌附着于非生物表面，并产生外多糖，使细菌细胞固定在这些定殖表面上。 AA产生的外多糖是€-1,6连接的N-乙酰基-D-葡萄糖胺（GLCNAC）单位的均聚物。 AA使用与Escherichia大肠杆菌，耶尔森氏菌的HMS和葡萄球菌表皮的ICA同源的四基因歌剧产生这种外多糖（PGA）。在AA中，操纵子PGAABCD携带PGAB编码的脱乙酰基酶（EC 3.5.1.41）。我们的初步数据表明，PGAB酶具有从PGA GlcNAC中去除乙酰基的能力。更有趣的是，我们发现PGAB脱离了预制的生物膜并抑制AA，pleuropneumoniae和S. epidermidis的生物膜形成，当添加到生长培养基中时。我们先前已经表明，从AA中分散酶（DSPB）也可以通过沉积PGA来防止几种革兰氏阴性和革兰氏阳性细菌物种的表面附着。与DSPB不同，新发现的酶PGAB是驻留在PGA中的GlcNAC的脱乙酰基酶，通过脱乙酰基化改变了PGA的电荷状态（富含阳性电荷）。这种酶活性表明，脱离/抑制的机制可能是通过对PGA聚合物上的排斥性相互作用的增加。重要的是，在这些生物体中，尤其是在AA中，可以理解脱乙酰化在生物膜去除或形成中的作用。我们将使用AA的PGAB作为模型系统来了解这些过程。我们的远程目标是了解PGA在AA致病性中的作用以及PGAB的脱乙酰基酶活性如何对这一作用至关重要。我们将使用体外和体内模型同时使用PGA在AA病毒中起关键作用的总体假设。具体而言，以下目的是研究：特定目标1。证明酶PGAB的PGA脱乙酰化能力对于其抗生素活性至关重要。特定目标2a。证明PGA的乙酰化状态和程度有助于AA中的生物膜形成。特定目标2B。证明外多糖PGA有助于AA致病性。