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Molecular Oral Microbiology

Robert C Shields, Paul A Jensen
Querying gene function in bacteria has been greatly accelerated by the advent of transposon sequencing (Tn-seq) technologies (related Tn-seq strategies are known as TraDIS, INSeq, RB-TnSeq and HITS). Pooled populations of transposon mutants are cultured in an environment and next-generation sequencing tools are used to determine areas of the genome that are important for bacterial fitness. In this review we provide an overview of Tn-seq methodologies and discuss how Tn-seq has been applied, or could be applied, to the study of oral microbiology...
February 9, 2019: Molecular Oral Microbiology
Leng Wu, Tao Gong, Xuedong Zhou, Jumei Zeng, Ruijie Huang, Yafei Wu, Yuqing Li
The Gram-negative anaerobe Porphyromonas gingivalis is not only a keystone periodontal pathogen, but also an emerging systemic pathogen. Although the newly discovered protein post-translational modification (PTM), lysine succinylation (Ksuc), appears to play an important role in modulating metabolic processes in bacteria, this PTM has not been investigated in P. gingivalis. In this study, we used a highly sensitive proteomics approach combining affinity enrichment with high-resolution liquid chromatography coupled with tandem mass spectrometry to examine Ksuc in P...
January 23, 2019: Molecular Oral Microbiology
Stephanie S Momeni, Tariq Ghazal, Hernan Grenett, Jennifer Whiddon, Stephen A Moser, Noel K Childers
Streptococcus mutans, a primary bacterium associated with dental caries, has four known clinical serotypes (c, e, f, and k). Some serotypes, presence of multiple serotypes and strains with collagen-binding proteins (CBP, Cnm and Cbm) have been linked with systemic disease. Evaluation of S. mutans serotype distribution and caries association is needed in the United States. The purpose of this study was to evaluate the prevalence of S. mutans serotypes from two cohorts of African American children in rural Alabama using 3 sample types (saliva, plaque, and individual S...
January 22, 2019: Molecular Oral Microbiology
Yan Yang, Mengying Mao, Lei Lei, Meng Li, Jiaxin Yin, Xinrong Ma, Xiang Tao, Yingming Yang, Tao Hu
The cariogenic pathogen Streptococcus mutans (S. mutans) effectively utilizes dietary sucrose for the synthesis of exopolysaccharides (EPS), which act as a scaffold for its biofilm and thus contribute to its cariogenic pathogenicity. Dextranase (Dex), which is a type of glucanase, participates in the degradation of water-soluble glucan; however, the structural features of the exopolysaccharides regulated by the dexA gene have received limited attention. Our recent studies reported novel protocols to fractionate and analyzed the structural characteristics of glucans from S...
January 19, 2019: Molecular Oral Microbiology
Melody Y Zeng, Irina Miralda, Cortney L Armstrong, Silvia M Uriarte, Juhi Bagaitkar
Neutrophils are phagocytic innate immune cells essential for killing bacteria via activation of a wide variety of effector responses and generation of large amounts of reactive oxygen species (ROS). Majority of the ROS in neutrophils is generated by activation of the superoxide-generating enzyme NADPH oxidase. Independent of their anti-microbial function, NADPH oxidase-derived ROS have emerged as key regulators of host immune responses and neutrophilic inflammation. Data from patients with inherited defects in the NADPH oxidase subunit alleles that ablate its enzyme function as well as mouse models demonstrate profound dysregulation of host inflammatory responses, neutrophil hyper-activation and tissue damage in response to microbial ligands or tissue trauma...
January 11, 2019: Molecular Oral Microbiology
Meng-Hsuan Ho, Richard J Lamont, Walter J Chazin, Huiqing Chen, Daphne F Young, Prashant Kumar, Hua Xie
Porphyromonas gingivalis is a keystone bacterium in the oral microbial communities that elicits a dysbiosis between the microbiota and the host. Therefore, inhibition of this organism in dental plaques has been one of the strategies for preventing and treating chronic periodontitis. We previously identified a Streptococcal ArcA derived Anti-P gingivalils Peptide (SAPP) that in vitro, is capable of repressing the expression of several virulence genes in the organism. This leads to a significant reduction in P gingivalis virulence potential, including its ability to colonize on the surface of Streptococcus gordonii, to invade human oral epithelial cells, and to produce gingipains...
December 2018: Molecular Oral Microbiology
Susan Yost, Ana E Duran-Pinedo
In this study, we characterized a serine protease from Tannerella forsythia that degrades gelatin, type I, and III collagen. Tannerella forsythia is associated with periodontitis progression and severity. The primary goal of this research was to understand the mechanisms by which T. forsythia contributes to periodontitis progression. One of our previous metatranscriptomic analysis revealed that during periodontitis progression T. forsythia highly expressed the bfor_1659 ORF. The N-terminal end is homologous to dipeptidyl aminopeptidase IV (DPP IV)...
December 2018: Molecular Oral Microbiology
J L Ebersole, R Peyyala, O A Gonzalez
This study examined the oral epithelial immunotranscriptome response patterns modulated by oral bacterial planktonic or biofilm challenge METHODS: We assessed gene expression patterns when epithelial cells were challenged with a multispecies biofilm composed of S. gordonii, F. nucleatum, and P. gingivalis representing a type of periodontopathic biofilm compared to challenge with the same species of planktonic bacteria RESULTS: Of the 579 human immunology genes, a substantial signal of the epithelial cells was observed to 181 genes...
November 8, 2018: Molecular Oral Microbiology
Yixiao Xing, Yunpeng Zhang, Linglu Jia, Xin Xu
Human periodontal ligament stem cells (PDLSCs), a type of dental tissue-derived mesenchymal stem cells (MSCs), can be clinically applied in periodontal tissue regeneration to treat periodontitis, which is initiated and sustained by bacteria. Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is a pertinent deleterious factor in the oral microenvironment. The aim of this study was to investigate the effect of LPS on the proliferation and osteogenic differentiation of PDLSCs, as well as the mechanisms involved...
November 2, 2018: Molecular Oral Microbiology
Naresh V R Mutha, Waleed K Mohammed, Natalio Krasnogor, Geok Y A Tan, Siew Woh Choo, Nicholas S Jakubovics
Cell-cell interactions between genetically distinct bacteria, known as coaggregation, are important for the formation of mixed-species biofilms such as dental plaque. Interactions lead to gene regulation in the partner organisms that may be critical for adaptation and survival in mixed-species biofilms. Here, gene regulation responses to coaggregation between Streptococcus gordonii and Fusobacterium nucleatum were studied using dual RNA-Seq. Initially, S. gordonii DL1 was shown to coaggregate strongly with F...
October 17, 2018: Molecular Oral Microbiology
Tao Gong, Boyu Tang, Xuedong Zhou, Jumei Zeng, Miao Lu, Xiaoxin Guo, Xian Peng, Lei Lei, Bo Gong, Yuqing Li
Streptococcus mutans is the primary etiological agent of human dental caries. Its major virulence factors, glucosyltransferases (Gtfs), utilize sucrose to synthesize extracellular polysaccharides (EPS), leading to the formation of dental plaque biofilm. The current study was designed to develop a novel self-targeting gene editing technology that targeted gtfs to inhibit biofilms formation. The CRISPR-Cas system (ie, clustered regularly interspaced short palindromic repeat, with CRISPR-associated proteins) provides sequence-specific protection against foreign genetic materials in archaea and bacteria, and has been widely developed for genomic engineering...
October 17, 2018: Molecular Oral Microbiology
Delphine Dufour, Alexandra Mankovskaia, Yuki Chan, Kamyar Motavaze, Siew-Ging Gong, Céline M Lévesque
The oral pathogen Streptococcus mutans communicates using a canonical Gram-positive quorum sensing system, CSP-ComDE. The CSP pheromone already known to be involved in the development of genetic competence positively influences the formation of persisters, dormant variants of regular cells that are highly tolerant to antimicrobial therapy. It is now believed that the persistence phenotype is the end result of a stochastic switch in the expression of toxin-antitoxin (TA) modules. TAs consist of a pair of genes that encode two components, a stable toxin and its cognate labile antitoxin...
October 8, 2018: Molecular Oral Microbiology
S Biswas, L Turner, I Biswas
Lactobacillus rhamnosus is a lactic acid bacterium with a diverse ecological habitat. We recently isolated a L. rhamnosus strain (LRB) from a healthy baby-tooth that had naturally fallen out. We determined the whole genome sequence of LRB and found that the isolate is closely genetically related to an intestinal isolate, L. rhamnosus GG (ATCC 53103). However, the LRB genome had lost about a 75-kb segment and undergone a genomic rearrangement. We assessed LRB's capacity to survive in the gut environment, at least temporarily...
October 2018: Molecular Oral Microbiology
S Yu, L Ding, D Liang, L Luo
Reprograming of metabolic pathways is critical in governing the polarization of macrophages into classical proinflammatory M1 or alternative anti-inflammatory M2 phenotypes in metabolic diseases, such as diabetes. Porphyromonas gingivalis, a keystone pathogen of periodontitis, causes an imbalance in M1/M2 activation, resulting in a hyperinflammatory environment that promotes the pathogenesis of periodontitis. However, whether P. gingivalis infection modulates metabolic pathways to alter macrophage polarization remains unclear...
October 2018: Molecular Oral Microbiology
K Sturød, G Salvadori, R Junges, F C Petersen
Streptococcus pneumoniae transformation occurs within a short competence window, during which the alternative sigma factor X (SigX) is activated to orchestrate the expression of genes allowing extracellular DNA uptake and recombination. Importantly, antibiotic stress promotes transcriptional changes that may affect more than 20% of the S. pneumoniae genome, including competence genes. These can be activated or repressed, depending on the antibiotic agent. For most antibiotics, however, it remains unknown whether transcriptional effects on competence translate into altered transformability...
October 2018: Molecular Oral Microbiology
D P Miller, Q Wang, A Weinberg, R J Lamont
Acinetobacter baumannii is a nosocomial, opportunistic pathogen that causes several serious conditions including meningitis, septicemia, endocarditis, and pneumonia. It can be found in the oral biofilm, which may be a reservoir for pneumonia and chronic obstructive pulmonary disease. Subgingival colonization by A. baumannii is associated with chronic and aggressive periodontitis as well as refractory periodontal disease. Porphyromonas gingivalis, a keystone periodontal pathogen localized to subgingival plaque, is also implicated in several chronic conditions including aspiration pneumonia...
October 2018: Molecular Oral Microbiology
Sylvio Redanz, Xingqun Cheng, Rodrigo A Giacaman, Carmen S Pfeifer, Justin Merritt, Jens Kreth
The majority of commensal oral streptococci are able to generate hydrogen peroxide (H2 O2 ) during aerobic growth, which can diffuse through the cell membrane and inhibit competing species in close proximity. Competing H2 O2 production is mainly dependent upon the pyruvate oxidase SpxB, and to a lesser extent the lactate oxidase LctO, both of which are important for energy generation in aerobic environments. Several studies point to a broad impact of H2 O2 production in the oral environment, including a potential role in biofilm homeostasis, signaling, and interspecies interactions...
October 2018: Molecular Oral Microbiology
Zezhang T Wen, Kathleen Scott-Anne, Sumei Liao, Arpan De, Meng Luo, Christopher Kovacs, Brendaliz S Narvaez, Roberta C Faustoferri, Qingzhao Yu, Christopher M Taylor, Robert G Quivey
Our recent studies have shown that BrpA in Streptococcus mutans plays a critical role in cell envelope biogenesis, stress responses, and biofilm formation. In this study, a 10-species consortium was used to assess how BrpA deficiency influences the establishment, persistence, and competitiveness of S. mutans during growth in a community under conditions typical of the oral cavity. Results showed that, like the wild-type, the brpA mutant was able to colonize and establish on the surfaces tested. Relative to the wild-type, however, the brpA mutant had a reduced ability to persist and grow in the 10-species consortium (P < ...
October 2018: Molecular Oral Microbiology
J L Brown, E A Yates, M Bielecki, T Olczak, J W Smalley
Streptococcus gordonii, an accessory pathogen and early colonizer of plaque, co-aggregates with many oral species including Porphyromonas gingivalis. It causes α-hemolysis on blood agar, a process mediated by H2 O2 and thought to involve concomitant oxidation of hemoglobin (Hb). Porphyromonas gingivalis has a growth requirement for heme, which is acquired mainly from Hb. The paradigm for Hb heme acquisition involves the initial oxidation of oxyhemoglobin (oxyHb) to methemoglobin (metHb), followed by heme release and extraction through the actions of K-gingipain protease and/or the HmuY hemophore-like protein...
August 2018: Molecular Oral Microbiology
N Buduneli, D A Scott
Cigarette smoking presents oral health professionals with a clinical and research conundrum: reduced periodontal vascular responsiveness to the oral biofilm accompanied by increased susceptibility to destructive periodontal diseases. This presents a significant problem, hampering diagnosis and complicating treatment planning. The aim of this review is to summarize contemporary hypotheses that help to explain mechanistically the phenomenon of a suppressed bleeding response to dysbiotic plaque in the periodontia of smokers...
August 2018: Molecular Oral Microbiology
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