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Query: UNIPROT:P06889 (Mol)
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The aim of this study is to analyze two polymorphisms in exon 1 of Mannose-binding lectin (MBL) gene in children with carious teeth and children caries-free in order to determine the frequencies of these polymorphisms and to investigate possible association between MBL polymorphisms and dental caries. Fourty-two children with carious teeth and 40 children caries-free participated in the study. Two-hundred microliters of peripheral blood samples were taken in EDTA tubes and genomic DNA was isolated. PCR-RFLP method was used with BanI and MboII digestion enzymes. The overall distribution of genotypes did not significantly differ between two groups and there was also no significant difference in the allele frequency of codon 54 wild type (allele A) (p=0.884, p=0.585). It has been concluded that further investigations may be required to show possible association between MBL and dental caries in which high number healthy children are participated.
Mol Immunol 2005 May
PMID:Might there be a link between mannose-binding lectin polymorphism and dental caries? 1582 2

Molecules that have no center of symmetry are able to convert light to its second harmonic, at twice the frequency and half the wavelength. This only happens with any efficiency at very high light intensities such as are given by a pulsed laser, and because the efficiency of the process depends on the square of the intensity, it will be focal plane selective in exactly the same way as two-photon excitation of fluorescence. Because of its unusual molecular structure and its high degree of crystallinity, collagen is, by far, the strongest source of second harmonics in animal tissue. Because collagen is also the most important structural protein in the mammalian body, this provides a very useful imaging tool for studying its distribution. No energy is lost in second-harmonic imaging, so the image will not fade, and because it is at a shorter wavelength than can be excited by two-photon fluorescence, it can be separated easily from multiple fluorescent probes. It is already proving useful in imaging collagen with high sensitivity in various tissues, including cirrhotic liver, normal and carious teeth, and surgical repair of tendons.
Methods Mol Biol 2006
PMID:Second-harmonic imaging of collagen. 1671 49

Cavity ring-down spectroscopy with an off-axis multipass cell and space separated detectors is proposed to record absorption spectra without modulation of the diode laser intensity. The spectral resolution is approximately 0.0003 cm-1. The whole spectrum is obtained for one continuous tuning of the laser frequency for approximately 20 ms. When comparing this method to conventional CRDS the required rise time is 1000 times slower. The recording of the whole spectrum for one measurement gives additional possibilities of signal extraction at relatively high noise. The technique is applied to absorption measurement of NO2 in atmosphere.
Spectrochim Acta A Mol Biomol Spectrosc 2007 Apr
PMID:Diode ring-down spectroscopy without intensity modulation in an off-axis multipass cavity. 1726 75

Checkerboard DNA-DNA hybridization (CKB) is a technique that provides a simultaneous quantitative analysis of 40 microbial species against up to 28 mixed microbiota samples on a single membrane; using digoxigenin (DIG)-labeled, whole-genome DNA probes. Developed initially to study the predominantly gram-negative dental plaque microorganisms involved in periodontitis, we modified the probe species composition to focus on putative pathogens involved in the development of dental caries. CKB analysis is applicable to species from other biodiverse ecosystems and to a large number of samples. The major limitations are that high-quality DNA is required for the preparation of DIG-labeled probes and standards, and that probe specificity requires careful evaluation. Overall, CKB analysis provides a powerful ecological fingerprint of highly biodiverse microbiota based on key cultivable bacteria.
Methods Mol Biol 2007
PMID:Checkerboard DNA-DNA hybridization technology using digoxigenin detection. 1733 32

Streptococcus mutans is a primary pathogen for dental caries in humans. CiaR and CiaH of S. mutans comprise a two-component signal transduction system (TCS) involved in regulating various virulent factors. However, the signal that triggers the CiaRH response remains unknown. In this study, we show that calcium is a signal for regulation of the ciaRH operon, and that a double-glycine-containing small peptide encoded within the ciaRH operon (renamed ciaX) mediates this regulation. CiaX contains a serine + aspartate (SD) domain that is shared by calcium-binding proteins. A markerless in-frame deletion of ciaX reduced ciaRH operon expression and diminished the calcium repression of operon transcription. Point mutations of the SD domain resulted in the same phenotype as the in-frame deletion, indicating that the SD domain is required for CiaX function. Further characterization of ciaX demonstrated that it is involved in calcium-mediated biofilm formation. Furthermore, inactivation of ciaR or ciaH led to the same phenotype as the in-frame deletion of ciaX, suggesting that all three genes are involved in the same regulatory pathway. Sequence analysis and real-time RT-PCR identified a putative CiaR binding site upstream of ciaX. We conclude that the ciaXRH operon is a three-component, self-regulatory system modulating cellular functions in response to calcium.
Mol Microbiol 2008 Oct
PMID:The cia operon of Streptococcus mutans encodes a unique component required for calcium-mediated autoregulation. 1868 38

Streptococcus mutans is the primary etiological agent of dental caries in man and other mammalian organisms. This bacterium metabolizes carbohydrates actively and thrives under anaerobic conditions by fermenting l-ascorbate (Asc) via the sga operon, which includes SgaT, PtxB, and PtxA. These three proteins are members of the Asc family of enzyme II (EII) complexes of the bacterial phosphotransferase system. Here, we report the crystal structure of PtxB, solved by single-wavelength anomalous dispersion phasing, and that of PtxA, solved by molecular replacement, from S. mutans. PtxB provides the first crystal structure of an EIIB from the Asc family, composed of a central beta sheet of parallel strands flanked by alpha helices on both sides. The structure of PtxB is similar to the structures of IIB(Mtl) (IIB subunit of mannitol PTS) and IIB(Cel) (IIB subunit of cellobiose) in Escherichia coli despite the low sequence identity. PtxA adopts a globular alpha/beta sandwich structure. The phosphorylation-site His68 is situated between beta2 and beta3, within a hydrophobic pocket. We found that the hydrogen bond on N(delta1) of the active-site histidine is a common means of ensuring that phosphate is on the correct N(varepsilon2) site in many EIIA families. Finally, a model of the PtxB-PtxA complex was constructed, and a PtxA-phospho-PtxB state is proposed. Analyses of the two structures shed light on the catalytic mechanism of the phosphotransferase system.
J Mol Biol 2009 Feb 20
PMID:Crystal structures of phosphotransferase system enzymes PtxB (IIB(Asc)) and PtxA (IIA(Asc)) from Streptococcus mutans. 1913 50

The aim of the study was to assess the presence of six common cariogenic bacteria from Cariostat-inoculated plaque samples of Japanese elementary school children through PCR analysis and check its associations with caries risk testing the validity of Cariostat as a caries risk assessment tool. This epidemiological school-based study investigated plaque samples of 399 Japanese elementary school children. Assessed using the Cariostat, 48.2% of the children had high caries risk. DNA detection of Streptococcus mutans, Streptococcus sobrinus, Streptococcus salivarius, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus fermentum and both S. mutans and S. sobrinus was seen in 65.2%, 24.1%, 69.7%, 17.5%, 7.8%, 19.3%, and 17.3% of the participants, respectively. Except for S. salivarius, the presence of all other investigated bacteria resulted in a statistically significant increase among the proportion of subjects with high caries risk. Caries risk assessed using Cariostat was significantly influenced by the presence of cariogenic bacteria. Being a selective medium for cariogenic bacteria, the Cariostat can be a useful and direct source of cariogenic bacterial DNA for PCR analysis while effectively assessing caries risk.
Mol Cell Probes 2009 Dec
PMID:Culture-based PCR analysis of plaque samples of Japanese school children to assess the presence of six common cariogenic bacteria and its association with caries risk. 1957 92

Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a "coat of many colors," enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.
Microbiol Mol Biol Rev 2009 Sep
PMID:Streptococcus adherence and colonization. 1972 Oct 85

Cavity ring-down spectroscopy is used to probe the optical absorption of the optical pseudo-two level system [Xe]4f(13) Yb(3+) in room temperature solution, a situation where the two-color pump-probe luminescence approach commonly used to study the other [Xe]4f(n) (2 < or = n < or = 12) trivalent lanthanide ions fails. A 1m optical cavity constructed from two highly reflective mirrors is used to obtain ring-down signals as a function of wavelength from 1 mL samples contained in a quartz cuvette placed in the center of the cavity. Absorption spectra constructed from these signals characteristic of the (6)H(15/2)-->(4)F(9/2) [Xe]4f(5) Dy(3+) and the (7)F(0)-->(5)D(0) [Xe]4f(6) Eu(3+) transitions are presented and compared to the corresponding single pass absorption and two-color pump-probe luminescence spectra to obtain sensitivity estimates. Finally the spectrum for the (2)F(5/2)-->(2)F(7/2) [Xe]4f(13) Yb(3+) transition for a model Yb(3+) complex in room temperature solution is obtained using cavity ring-down spectroscopy for the first time.
Spectrochim Acta A Mol Biomol Spectrosc 2010 Apr
PMID:Cavity ring-down observation of Yb(3+) optical absorption in room temperature solution. 2013 3

Lactobacilli have been associated with the presence and progression of dental caries. Nevertheless, the relation between certain species or genotypes of Lactobacillus and caries is unclear and there are no data available for the Thai population. This study aimed to examine the distribution of species and genotypes of oral Lactobacillus among children with rather high caries prevalence, and to investigate whether certain species or genotypes were more related to caries activity than others. One hundred and sixty-five children were examined for caries status. Saliva samples were collected and the numbers of lactobacilli were counted. A total of 357 Lactobacillus isolates from 59 children were identified to species level by 16S ribosomal RNA genes polymerase chain reaction (PCR) -restriction fragment length polymorphism and 16S ribosomal RNA gene sequencing. Furthermore, 304 isolates from 56 children were genotyped using arbitrarily primed PCR. Significant correlation was found between levels of lactobacilli and dental caries (P < 0.001). Among the 10 identified species of Lactobacillus, L. salivarius was more prevalent in children with moderate to high caries prevalence compared with children with low caries prevalence, while L. fermentum was the most predominant species in all study groups. Moreover, a genetic heterogeneity of Lactobacillus species was found among the children and those with high caries prevalence tended to be colonized with more than one clonal type. In summary, L. salivarius may be a putative caries pathogen among preschool Thai children.
Mol Oral Microbiol 2010 Apr
PMID:Lactobacillus species and genotypes associated with dental caries in Thai preschool children. 2033 3


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