权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Human serum phage induction in Aggregatibacter actinomycetemcomitans

放线聚集杆菌中人血清噬菌体的诱导

基本信息

批准号：
10200010
负责人：
Gaoyan Grace Tang-Siegel
金额：
$ 15.6万
依托单位：
UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2023-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10200010
关键词：
Actinobacillus actinomycetemcomitans Adopted Affect American Antibiotic Resistance Antibiotics Area Bacteria Bacterial Chromosomes Bacterial DNA Bacterial Infections Bacteriophages Biological Models Blood Blood Vessels Cells Clinical Culture Media Cytolysis DNA DNA sequencing Data Development Disease Enhancers Environment Foundations Future Genes Genetic Genomic DNA Goals Gram-Negative Bacteria Growth Human Immune Sera Immune system Infection Infective endocarditis Inflammation Inflammatory Insertion Mutation Investigation Knowledge Laboratories Lead Libraries Lytic Lytic Phase Mammals Membrane Microbial Biofilms Modeling Mouth Diseases Nutrient Optics Oral Parents Pattern Periodontal Diseases Periodontal Pocket Periodontitis Permeability Phage Receptors Phenotype Physiological Population Process Prophages Proteins RNA Regulation Research Research Proposals Resistance Risk Serotyping Serum Source Specificity Stream Surface Systemic infection Therapeutic Tissues Work absorption bacterial fitness bacterial metabolism combat density fitness in vivo microorganism mutant novel novel therapeutic intervention novel therapeutics oral bacteria oral microbial community oral pathogen pathogenic bacteria prevent protein aggregation receptor resistant strain tool transcriptomics

项目摘要

Project Summary/Abstract Periodontitis is an inflammatory disease of the periodontium caused by bacterial biofilms and affects approximately 65 million Americans. Periodontal pockets serve as bacterial reservoirs and create potential risks to develop systemic illness. Aggregatibacter actinomycetemcomitans, an oral colonizer in 20% of the population, is a causative agent of periodontitis and infective endocarditis. The increasing antibiotic-resistant strains and the limitation of developing new antibiotics demand alternative therapeutics to cure bacterial infections. Bacteriophage therapy is listed as the top alternative and has successfully treated several bacterial infections. Currently, no phage therapeutics has been pursued to treat infections caused by oral bacteria. Development of new phage therapeutics requires understanding phage infection and replication in vivo. This knowledge is lacking in the human oral microbiota. The ultimate goal of this proposal is to develop alternative therapeutics to combat bacteria-associated oral diseases and, the immediate goal is to establish a phage infection model system to acquire the knowledge of phage infection and replication in oral pathogens. A. actinomycetemcomitans develops mechanisms to resist serum killing and survives in the inflammatory periodontal pockets and the blood. Both environments provide serum as the main nutrient source for bacterial growth. However, our data indicated that selective clinical strains of this microorganism clearly demonstrated a “bimodal” growth pattern only in the presence of human serum, and the secondary increase of optical density was due to bacterial lysis, therefore were grouped as “serum-sensitive” strains. This novel finding leaded to the discovery of a 44kb Aggregatibacter phage S1249 in the serum-sensitive strain and, 20% of the phage genes were up regulated over 10-fold in human serum comparing to other growth media. We propose that human serum induces the replication of this phage resulting in bacterial killing and, therefore phage S1249 is a potential candidate to be used for studying phage replication and regulation in this oral pathogen. We will start our investigation by accomplishing two specific aims in this proposal: Firstly, we will develop a phage infection model system by deletion of the prophage DNA from the bacterial chromosome to cure this phage, following by re-infection with the same phage. Phage induction and bacterial fitness in human serum will be characterized and compared between the wild type and its isogenic cured strain at the RNA and protein levels. Secondly, we will determinate the infection specificity of phage S1249 by using this phage to infect other serum-resistant strains to evaluate the growth fitness of those newly infected strains in human serum. This physiologically relevant model system simulates periodontal environment and will provide fundamental tools and knowledge for our future investigations, which includes: identification of bacterial surface receptors for the phage absorption and, determination of human serum components that trigger phage induction. Ultimately, the knowledge we gain will unravel phage infection and replication regulation by serum in this oral pathogen.

项目总结/摘要牙周炎是由细菌生物膜引起的牙周组织炎症性疾病，大约6500万美国人。牙周袋作为细菌储存库，发展成系统性疾病的风险。伴随放线菌聚集杆菌，20%的口腔定植者，是牙周炎和感染性心内膜炎的病原体。日益增强的抗真菌能力菌株和开发新抗生素的局限性需要替代疗法来治愈细菌性肺炎，感染.噬菌体治疗被列为首选，并已成功地治疗了几种细菌感染.目前，还没有噬菌体治疗剂被用于治疗由口腔细菌引起的感染。开发新的噬菌体疗法需要了解体内噬菌体感染和复制。这对人类口腔微生物群缺乏了解。该提案的最终目标是开发替代对抗细菌相关口腔疾病的治疗方法，当前目标是建立噬菌体感染模型系统，以获得口腔病原体中噬菌体感染和复制的知识。 A.伴放线菌形成抵抗血清杀伤的机制，并在炎性牙周袋和血液两种环境都提供血清作为细菌的主要营养源。增长然而，我们的数据表明，这种微生物的选择性临床菌株清楚地表明， “双峰”生长模式仅在人血清存在时出现，且继发光密度增加是由于细菌裂解，因此被归类为“血清敏感”菌株。这一新发现导致了在血清敏感菌株中发现了44 kb的聚集杆菌噬菌体S1249，与其他生长培养基相比，在人血清中上调超过10倍。我们建议人类血清诱导这种噬菌体的复制，导致细菌杀伤，因此噬菌体S1249是一种为研究该口腔病原体中噬菌体的复制和调控提供了潜在的候选者。我们将开始我们的研究通过实现两个具体目标，在这个建议：首先，我们将发展噬菌体感染通过从细菌染色体中删除原噬菌体DNA来治愈这种噬菌体，然后再次感染相同的噬菌体噬菌体诱导和人血清中的细菌适应性将被表征并在RNA和蛋白质水平上比较了野生型与其等基因型的治愈株。其次我们利用噬菌体S1249感染其它抗血清的大肠杆菌，菌株，以评估这些新感染的菌株在人血清中的生长适应性。这在生理上相关的模型系统模拟牙周环境，并将提供基本的工具和知识为我们未来的研究，其中包括：鉴定噬菌体的细菌表面受体吸收和测定触发噬菌体诱导的人血清组分。最终我们获得的知识将解开噬菌体感染和复制调节血清在这种口腔病原体。