Publications by authors named "Nicholas C Heng"

Orthodontic braces can impede oral hygiene and promote halitosis. The aim of the study was to investigate the effect of the oral probiotic Streptococcus salivarius M18 on oral hygiene indices and halitosis in patients wearing orthodontic braces. The study was a prospective, randomized, triple-blind, placebo-controlled trial.

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We report here the draft genome sequence of Weissella confusa MBF8-1, an isolate from a homemade fermented soybean product that produces sucrases and exhibits antibacterial (bacteriocin) activity. The draft genome of W. confusa MBF8-1 comprises a 2.

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Members of the Gram-positive lactic acid bacteria (LAB) are well-known for their beneficial properties as starter cultures and probiotics. Many LAB species produce ribosomally synthesized proteinaceous antibiotics (bacteriocins). Weissella confusa MBF8-1 is a strain isolated from a fermented soybean product that not only produces useful exopolysaccharides but also exhibits bacteriocin activity, which we call weissellicin MBF.

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Considerable human illness can be linked to the development of oral microbiota disequilibria. The predominant oral cavity commensal, Streptococcus salivarius has emerged as an important source of safe and efficacious probiotics, capable of fostering more balanced, health-associated oral microbiota. Strain K12, the prototype S.

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Aim: To determine the relationship between periodontal pathogen load and anti-human heat shock protein 60 (hHSP60) antibodies in patients with established cardiovascular disease (CVD).

Materials And Methods: Participants were cardiovascular patients (n = 74) with a previous hospital admission for myocardial infarction. Concurrent periodontal pathogen load of Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia and Aggregatibacter actinomycetemcomitans was determined using quantitative real-time PCR.

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Streptococcus salivarius is a Gram-positive bacterial commensal and pioneer colonizer of the human oral cavity. Many strains produce ribosomally synthesized proteinaceous antibiotics (bacteriocins), and some strains have been developed for use as oral probiotics. Here, we present the draft genome sequence of the bacteriocin-producing oral probiotic S.

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Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L.

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DysI is identified as the protein that confers specific immunity to dysgalacticin, a plasmid-encoded streptococcal bacteriocin. dysI is transcribed as part of the copG-repB-dysI replication-associated operon. DysI appears to function at the membrane level to prevent the inhibitory effects of dysgalacticin on glucose transport, membrane integrity, and intracellular ATP content.

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For over 30 years, the chain termination method of DNA sequencing (commonly known as Sanger sequencing) has been the mainstay of any DNA sequencing project. In the past, whole-genome sequencing employing exclusively Sanger chemistry has been a labor-intensive and costly exercise and an option unfeasible for the average research group. However, within the last 4 years, the introduction of three high-throughput sequencing technologies (454, SOLiD, and Illumina) has revolutionized genomics by facilitating unprecedented levels (up to gigabasepairs) of reliable DNA sequence output in a relatively short time frame and at a much lower cost per sequenced basepair.

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Streptococcus salivarius has an exclusive and intimate association with humans. We are its sole natural host, and its contribution to the relationship appears overwhelmingly benevolent. Beautifully adapted to its preferred habitat, the human tongue, it only rarely ventures far from this location in the healthy host and indeed appears ill-equipped to become invasive due to a scarcity of virulence attributes.

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Members of the Gram-positive bacterial genus Streptococcus are a diverse collection of species inhabiting many body sites and range from benign, nonpathogenic species to those causing life-threatening infections. The streptococci are also prolific producers of bacteriocins, which are ribosomally synthesized proteinaceous antibiotics that kill or inhibit species closely related to the producer bacterium. With the emergence of bacterial resistance to conventional antibiotics, there is an impetus to discover, and implement, new and preferably 'natural' antibiotics to treat or prevent bacterial infections, a niche that bacterial interference therapy mediated by bacteriocins could easily fill.

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Streptococcus uberis, a causal agent of bovine mastitis, produces ubericin A, a 5.3-kDa class IIa (pediocin-like) bacteriocin, which was purified and characterized. The uba locus comprises two overlapping genes: ubaA (ubericin A precursor peptide) and ubaI (putative immunity protein).

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The production of streptocins STH(1) and STH(2) by Streptococcus gordonii DL1 (Challis) is directly controlled by the competence regulon, which requires intact comR and comAB loci. The streptocin (sth) locus comprises two functional genes, sthA and sthB. Whereas STH(1) activity requires sthA alone, STH(2) activity depends on both genes.

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Streptococcus salivarius strains commonly produce bacteriocins as putative anti-competitor or signalling molecules. Here we report that bacteriocin production by the oral probiotic strain S. salivarius K12 is encoded by a large (ca.

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In naturally-competent streptococci such as Streptococcus pneumoniae, expression of the late competence operons is regulated by ComX (sigma(X)), the competence-specific alternative sigma factor. In this study, duplicate genes (comR1 and comR2) encoding the putative ComX homologue of the oral bacterium Streptococcus gordonii were identified. Like the identical twin comX loci of S.

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Streptococcus mutans UA159, the genome sequence reference strain, exhibits nonlantibiotic mutacin activity. In this study, bioinformatic and mutational analyses were employed to demonstrate that the antimicrobial repertoire of strain UA159 includes mutacin IV (specified by the nlm locus) and a newly identified bacteriocin, mutacin V (encoded by SMU.1914c).

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Streptococcus mutans UA159, the genome sequence reference strain, exhibits nonlantibiotic bacteriocin (mutacin) activity. In this study, we have combined bioinformatic and mutational analyses to identify the ABC transporter designated NlmTE, which is required for mutacin biogenesis in strain UA159 as well as in another mutacin producer, S. mutans N.

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Production of the novel bacteriocin streptococcin A-M57 (SA-M57) by Streptococcus pyogenes strains of M-protein type 57 is plasmid-associated. Plasmid pDN571 (3351bp) harbored by S. pyogenes 71-724, the prototype M-type 57 strain, has been completely sequenced and contains three putative open reading frames (repA, scnM57 and ORF3).

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Lactobacilli are common inhabitants of the gastrointestinal tracts of mammals and have received considerable attention due to their putative health-promoting properties. Little is known about the traits that enhance the ability of these bacteria to inhabit the gastrointestinal tract. In this paper we describe the development and application of a strategy based on in vivo expression technology (IVET) that enables detection of Lactobacillus reuteri genes specifically induced in the murine gut.

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