Updated on 2021/12/27

写真a

 
NAKANO Michiyo
 
Organization
Medicine, Dentistry and Pharmaceutical Sciences Professor
Position
Professor
External link

Degree

  • PhD ( Osaka University )

Research Areas

  • Life Science / Social dentistry

Professional Memberships

  • 日本小児歯科学会

  • 岡山県小児保健協会

  • 歯科虐待防止研究会

  • 日本小児保健協会

  • 国際歯科研究学会日本部会

  • 歯科基礎医学会

  • 日本歯科医学教育学会

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Papers

  • Relationship between IgA Nephropathy and Porphyromonas gingivalis; Red Complex of Periodontopathic Bacterial Species Reviewed

    Nagasawa Y, Nomura R, Misaki T, Ito S, Naka S, Wato K, Okunaka M, Watabe M, Fushimi K, Tsuzuki K, Matsumoto-Nakano M, Nakano K.

    22 ( 23 )   2021.12

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  • Prognostic association of starvation-induced gene expression in head and neck cancer. Reviewed

    Hamada M, Inaba H, Nishiyama K, Yoshida S, Yura Y, Matsumoto-Nakano M, Uzawa N.

    11 ( 1 )   2021.9

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    DOI: 10.1038/s41598-021-9

  • Efficacy of FimA antibody and clindamycin in silkworm larvae stimulated with Porphyromonas gulae. International journal

    Sho Yoshida, Hiroaki Inaba, Ryota Nomura, Masaru Murakami, Hidemi Yasuda, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

    Journal of oral microbiology   13 ( 1 )   1914499 - 1914499   2021.4

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    Objective: Porphyromonas gulae, a major periodontal pathogen in animals, possesses fimbriae that have been classified into three genotypes (A, B, C) based on the diversity of fimA genes encoding fimbrillin protein (FimA). P. gulae strains with type C fimbriae were previously shown to be more virulent than other types. In this study, we further examined the host toxicity mediated by P. gulae fimbriae by constructing recombinant FimA (rFimA) expression vectors for each genotype and raised antibodies to the purified proteins. Methods and Results: All larvae died within 204 h following infection with P. gulae type C at the low-dose infection, whereas type A and B did not. Among fimA types, the survival rates of the larvae injected with rFimA type C were remarkably decreased, while the survival rates of the larvae injected with rFimA type A and type B were greater than 50%. Clindamycin treatment inhibited the growth of type C strains in a dose-dependent manner, resulting in an increased rate of silkworm survival. Finally, type C rFimA-specific antiserum prolonged the survival of silkworm larvae stimulated by infection with P. gulae type C strain or injection of rFimA type C protein. Conclusion: These results suggested that type C fimbriae have high potential for enhancement of bacterial pathogenesis, and that both clindamycin and anti-type C rFimA-specific antibodies are potent inhibitors of type C fimbriae-induced toxicity. This is the first report to establish a silkworm infection model using P. gulae for toxicity assessment.

    DOI: 10.1080/20002297.2021.1914499

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  • Inhibitory effects of flavedo, albedo, fruits, and leaves of Citrus unshiu extracts on Streptococcus mutans. International journal

    Ryota Nomura, Jumpei Ohata, Masatoshi Otsugu, Rena Okawa, Shuhei Naka, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Archives of oral biology   124   105056 - 105056   2021.4

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    OBJECTVES: Citrus unshiu has been shown to exhibit antimicrobial effects against citrus diseases. In the present study, C. unshiu was divided into flavedo, albedo, fruits, and leaves; the inhibitory effects of these extracts on Streptococcus mutans, a major pathogen of dental caries, were investigated. DESIGN: C. unshiu specimens were separated into flavedo, albedo, fruits, and leaves. First, pH values and polyphenol amounts in Citrus extracts were measured. In addition, Citrus extract was added to the bacterial suspensions of S. mutans MT8148, and inhibitory effects of C. unshiu extracts on MT8148 for antimicrobial activity, bacterial growth, and biofilm formation were analyzed. These assays were also performed using C. sinensis extracts. RESULTS: Among these extracts, albedo exhibited a pH value closest to neutral, while the fruits exhibited the most acidic pH value; the pH values significantly differed between these extracts (P < 0.05). In addition, the amounts of polyphenols were significantly higher in albedo than in other extracts (P < 0.001). All extracts showed inhibitory effects on MT8148 for antimicrobial activity, bacterial growth and biofilm formation. These inhibitory effects were significantly stronger in flavedo, albedo, and fruits, compared with leaves (P < 0.05). Furthermore, extracts of Citrus sinensis also showed inhibitory effects on S. mutans, although these effects were weaker than the effects of C. unshiu. CONCLUSION: These results suggest that extracts from C. unshiu fruits exhibit inhibitory effects on S. mutans, among which albedo may be especially useful for dental caries prevention due to its neutral pH and abundant polyphenols, in addition to its inhibitory effects.

    DOI: 10.1016/j.archoralbio.2021.105056

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  • Non-alcoholic steatohepatitis caused by oral bacteria Invited Reviewed

    Naka S, Matsumoto-Nakano M

    Pediatric Dental Journal   31 ( 1 )   11 - 16   2021.4

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  • Streptococcus mutans induces IgA nephropathy-like glomerulonephritis in rats with severe dental caries. International journal

    Shuhei Naka, Kaoruko Wato, Taro Misaki, Seigo Ito, Daiki Matsuoka, Yasuyuki Nagasawa, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Scientific reports   11 ( 1 )   5784 - 5784   2021.3

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    The mechanisms underlying immunoglobulin A nephropathy (IgAN), the most common chronic form of primary glomerulonephritis, remain poorly understood. Streptococcus mutans, a Gram-positive facultatively anaerobic oral bacterium, is a common cause of dental caries. In previous studies, S. mutans isolates that express Cnm protein on their cell surface were frequently detected in IgAN patients. In the present study, inoculation of Cnm-positive S. mutans in the oral cavities of 2-week-old specific-pathogen free Sprague-Dawley rats fed a high-sucrose diet for 32 weeks produced severe dental caries in all rats. Immunohistochemical analyses of the kidneys using IgA- and complement C3-specific antibodies revealed positive staining in the mesangial region. Scanning electron microscopy revealed a wide distribution of electron dense deposits in the mesangial region and periodic acid-Schiff staining demonstrated prominent proliferation of mesangial cells and mesangial matrix. These results suggest that IgAN-like glomerulonephritis was induced in rats with severe dental caries by Cnm-positive S. mutans.

    DOI: 10.1038/s41598-021-85196-4

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  • Roles of Porphyromonas gulae proteases in bacterial and host cell biology. International journal

    Alam Saki Urmi, Hiroaki Inaba, Ryota Nomura, Sho Yoshida, Naoya Ohara, Fumitoshi Asai, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

    Cellular microbiology   e13312   2021.1

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    Porphyromonas gulae, an animal-derived periodontal pathogen, expresses several virulence factors, including fimbria, lipopolysaccharide (LPS), and proteases. We previously reported that its invasive efficiency was dependent on fimbriae types. In addition, P. gulae LPS increased inflammatory responses via toll-like receptors. The present study was conducted to investigate the involvement of P. gulae proteases in bacterial and host cell biology. P. gulae strains showed an ability to agglutinate mouse erythrocytes and also demonstrated coaggregation with Actinomyces viscosus, while the protease inhibitors antipain, PMSF, TLCK, and leupeptin diminished P. gulae proteolytic activity, resulting in inhibition of hemagglutination and coaggregation with A. viscosus. In addition, specific proteinase inhibitors were found to reduce bacterial cell growth. P. gulae inhibited Ca9-22 cell proliferation in a multiplicity of infection- and time-dependent manner. Additionally, P. gulae-induced decreases in cell contact and adhesion-related proteins were accompanied by a marked change in cell morphology from well spread to rounded. In contrast, inhibition of protease activity prevented degradation of proteins, such as E-cadherin, β-catenin, and focal adhesion kinase, and also blocked inhibition of cell proliferation. Together, these results indicate suppression of the amount of human proteins, such as γ-globulin, fibrinogen and fibronectin, by P. gulae proteases, suggesting that a novel protease complex contributes to bacterial virulence. This article is protected by copyright. All rights reserved.

    DOI: 10.1111/cmi.13312

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  • Porphyromonas gulae lipopolysaccharide elicits inflammatory responses through toll-like receptor 2 and 4 in human gingivalis epithelial cells. International journal

    Hiroaki Inaba, Sho Yoshida, Ryota Nomura, Yukio Kato, Fumitoshi Asai, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

    Cellular microbiology   22 ( 12 )   e13254   2020.12

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    Porphyromonas gulae, a Gram-negative black-pigmented anaerobe, has been associated with periodontal disease in companion animals and its virulence has been attributed to various factors, including lipopolysaccharide (LPS), protease and fimbriae. Toll-like receptors (TLRs) recognise pathogen-associated molecular patterns, such as peptidoglycan, lipids, lipoproteins, nucleic acid and LPS. Following P. gulae infection, some inflammatory responses are dependent on both TLR2 and TLR4. In addition, a recent clinical study revealed that acute and persistent inflammatory responses enhance the expressions of TLR2 and TLR4 in the oral cavity. In this study, we investigated the interaction between P. gulae LPS and human gingivalis epithelial cells (Ca9-22 cells). P. gulae LPS was found to increase TLR2 and TLR4 mRNA expressions and protein productions, and enhanced inflammatory responses, such as COX2 , TNF-ɑ, IL-6 and IL-8. Stimulated Ca9-22 cells exhibited phosphorylation of ERK1/2 and p38, and their inhibitors diminished inflammatory responses, while knockdown of the TLR2 and/or TLR4 genes with small interfering RNA (siRNA) prevented inflammatory responses. Moreover, p38 and ERK1/2 phosphorylation was decreased in TLR2 and TLR4 gene knockdown cells. These findings suggest that P. gulae LPS activates p38 and ERK1/2 via TLR2 and TLR4, leading to inflammatory responses in human gingival epithelial cells.

    DOI: 10.1111/cmi.13254

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  • Intravenous administration of Streptococcus mutans induces IgA nephropathy-like lesions.

    Shuhei Naka, Kaoruko Wato, Taro Misaki, Seigo Ito, Yasuyuki Nagasawa, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Clinical and experimental nephrology   24 ( 12 )   1122 - 1131   2020.12

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    BACKGROUND: IgA nephropathy (IgAN) is one of the most frequently occurring types of chronic glomerulonephritis. Previous analyses have revealed that a major pathogen of dental caries, Streptococcus mutans [which expresses collagen-binding protein (Cnm) on its surface], is involved in the pathogenesis of IgAN. METHODS: Cnm-positive S. mutans isolated from a patient with IgAN was intravenously administered to specific pathogen-free Sprague-Dawley rats to evaluate their kidney conditions. RESULTS: The urinary protein level of the S. mutans group reached a plateau at 30 days, with increased numbers of mesangial cells and an increased mesangial matrix. The numbers of rats with IgA-positive and/or C3-positive glomeruli were significantly greater in the S. mutans group than in the control group at 45 days (P < 0.05). Electron microscopy analyses revealed electron-dense depositions in the mesangial area among rats in the S. mutans group. There were significantly more CD68-positive cells (macrophages) in the glomeruli of the S. mutans group than in the glomeruli of the control group during the late phase (P < 0.05), similar to the findings in patients with IgAN. CONCLUSION: Our results suggested that intravenous administration of Cnm-positive S. mutans caused transient induction of IgAN-like lesions in rats.

    DOI: 10.1007/s10157-020-01961-1

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  • Potential involvement of Streptococcus mutans possessing collagen binding protein Cnm in infective endocarditis. International journal

    Ryota Nomura, Masatoshi Otsugu, Masakazu Hamada, Saaya Matayoshi, Noboru Teramoto, Naoki Iwashita, Shuhei Naka, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Scientific reports   10 ( 1 )   19118 - 19118   2020.11

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    Streptococcus mutans, a significant contributor to dental caries, is occasionally isolated from the blood of patients with infective endocarditis. We previously showed that S. mutans strains expressing collagen-binding protein (Cnm) are present in the oral cavity of approximately 10-20% of humans and that they can effectively invade human umbilical vein endothelial cells (HUVECs). Here, we investigated the potential molecular mechanisms of HUVEC invasion by Cnm-positive S. mutans. The ability of Cnm-positive S. mutans to invade HUVECs was significantly increased by the presence of serum, purified type IV collagen, and fibrinogen (p < 0.001). Microarray analyses of HUVECs infected by Cnm-positive or -negative S. mutans strains identified several transcripts that were differentially upregulated during invasion, including those encoding the small G protein regulatory proteins ARHGEF38 and ARHGAP9. Upregulation of these proteins occurred during invasion only in the presence of serum. Knockdown of ARHGEF38 strongly reduced HUVEC invasion by Cnm-positive S. mutans. In a rat model of infective endocarditis, cardiac endothelial cell damage was more prominent following infection with a Cnm-positive strain compared with a Cnm-negative strain. These results suggest that the type IV collagen-Cnm-ARHGEF38 pathway may play a crucial role in the pathogenesis of infective endocarditis.

    DOI: 10.1038/s41598-020-75933-6

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  • Identification and functional analysis of glutamine transporter in Streptococcus mutans Reviewed

    Morikawa Y, Morimoto S, Yoshida E, Naka S, Inaba H, Matsumoto-Nakano M

    Journal of Oral Microbiology   12 ( 1 )   2020.8

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    DOI: 10.1080/20002297.202

  • Author Correction: Inhibition of Porphyromonas gulae and periodontal disease in dogs by a combination of clindamycin and interferon alpha. International journal

    Ryota Nomura, Hiroaki Inaba, Hidemi Yasuda, Mitsuyuki Shirai, Yukio Kato, Masaru Murakami, Naoki Iwashita, So Shirahata, Sho Yoshida, Saaya Matayoshi, Junya Yasuda, Nobuaki Arai, Fumitoshi Asai, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Scientific reports   10 ( 1 )   7295 - 7295   2020.4

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    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

    DOI: 10.1038/s41598-020-63861-4

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  • Oral Lactobacilli Related to Caries Status of Children with Primary Dentition. Reviewed International coauthorship International journal

    Jinthana Lapirattanakul, Ryota Nomura, Rena Okawa, Setsuyo Morimoto, Pornpen Tantivitayakul, Thaniya Maudcheingka, Kazuhiko Nakano, Michiyo Matsumoto-Nakano

    Caries research   54 ( 2 )   194 - 204   2020.4

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    Oral lactobacilli are members of a group of bacteria implicated in caries progression, although information regarding their transmission, colonization, and caries-associated species is not well established. This study isolated oral lactobacilli from a group of children with primary dentition for determination of Lactobacillus prevalence, detection of Streptococcus mutans, a major pathogen of caries initiation, and dental caries status of the children. Species of Lactobacillus isolates were determined from examination of 16S rDNA sequences. Subsequently, the most prevalent species was evaluated for involvement in caries status, and binding ability to type I collagen of all Lactobacillus isolates was determined in association with caries status. Multilocus sequence typing (MLST) of eleven loci was carried out to study strains of the predominant Lactobacillus sp. The detection of oral lactobacilli together with S. mutans was significantly associated with the highest dental caries indices, but there was no involvement of collagen-binding properties of Lactobacillus isolates in caries status. Lactobacillus fermentum was the most prevalent, and its presence was related to high scores of caries indices. MLST analysis of L. fermentum population could not specify a particular clone associated with caries status, but revealed sharing of identical L. fermentum strains among children in the same classrooms. Taken together, the data contributed useful information on the role of oral lactobacilli, in particular L. fermentum in dental caries.

    DOI: 10.1159/000506468

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  • Inhibitory effect of a mouth rinse formulated with chlorhexidine gluconate, ethanol, and green tea extract against major oral bacterial species.

    Ryota Nomura, Hiroaki Inaba, Saaya Matayoshi, Sho Yoshida, Yuki Matsumi, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Journal of oral science   62 ( 2 )   206 - 211   2020.3

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    Mouth rinses are a useful supplementary tool for the prevention of oral infectious diseases. Although the antimicrobial effects of mouth rinses have been investigated, there are few studies focusing on the comparison of the effects among various oral bacterial species. In the present study, the inhibitory effect of a commercial mouth rinse, "ConCoolF," and each of its major components, chlorhexidine gluconate, ethanol, and green tea extract, on multiple species of oral bacteria were investigated. Inhibition of bacterial growth was observed in all cariogenic streptococcal species with different genera, serotypes, and strains isolated from different countries when either the complete mouth rinse or chlorhexidine gluconate were used. However, no growth inhibition was observed when the bacteria were exposed to ethanol or green tea extract. Interestingly, growth inhibition was greatly reduced in non-cariogenic streptococci compared with cariogenic streptococci. In addition, both the mouth rinse and chlorhexidine gluconate inhibited the biofilms formed by both Streptococcus mutans (S. mutans) and Porphyromonas gingivalis (P. gingivalis), among which the inhibitory effect against S. mutans was higher than that against P. gingivalis. These results suggest that a mouth rinse containing chlorhexidine gluconate, ethanol, and green tea extract, or chlorhexidine gluconate alone, exhibits antimicrobial activity against several oral bacteria species, having greater activity against pathogenic bacteria.

    DOI: 10.2334/josnusd.18-0483

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  • Inhibition of Porphyromonas gulae and periodontal disease in dogs by a combination of clindamycin and interferon alpha. International journal

    Ryota Nomura, Hiroaki Inaba, Hidemi Yasuda, Mitsuyuki Shirai, Yukio Kato, Masaru Murakami, Naoki Iwashita, So Shirahata, Sho Yoshida, Saaya Matayoshi, Junya Yasuda, Nobuaki Arai, Fumitoshi Asai, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Scientific reports   10 ( 1 )   3113 - 3113   2020.2

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    Porphyromonas gulae is a major periodontal pathogen in dogs, which can be transmitted to their owners. A major virulence factor of P. gulae consists of a 41-kDa filamentous appendage (FimA) on the cell surface, which is classified into three genotypes: A, B, and C. Thus far, inhibition of periodontal disease in dogs remains difficult. The present study assessed the inhibitory effects of a combination of clindamycin and interferon alpha (IFN-α) formulation against P. gulae and periodontal disease. Growth of P. gulae was significantly inhibited by clindamycin; this inhibition had a greater effect on type C P. gulae than on type A and B isolates. In contrast, the IFN-α formulation inhibited the expression of IL-1β and COX-2 elicited by type A and B isolates, but not that elicited by type C isolates. Furthermore, periodontal recovery was promoted by the administration of both clindamycin and IFN-α formulation to dogs undergoing periodontal treatment; moreover, this combined treatment reduced the number of FimA genotypes in oral specimens from treated dogs. These results suggest that a combination of clindamycin and IFN-α formulation inhibit P. gulae virulence and thus may be effective for the prevention of periodontal disease induced by P. gulae.

    DOI: 10.1038/s41598-020-59730-9

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  • Case of autoimmune neutropenia with severe marginal periodontitis Reviewed

    2019.12

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  • Case of autoimmune neutropenia with severe marginal periodontitis

    Setsuyo Morimoto, Keiko Hirano, Keiko Tabata, Haruka Asaumi, Yuko Morikawa, Yuki Matsumi, Shuhei Naka, Michiyo Matsumoto-Nakano

    PEDIATRIC DENTAL JOURNAL   29 ( 3 )   138 - 145   2019.12

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    Early onset periodontitis is rarely seen in infants, though often leads to an acute and serious clinical course when encountered in such patients. Autoimmune neutropenia presents systemic and dental symptoms, as depressed resistance to bacterial infection is caused by a disorder that reduces the number of neutrophils. This disease can result in not only gingival inflammation but also destruction of periodontal tissues, such as attachment loss, alveolar bone absorption, and early tooth loss in primary as well as mixed dentition. Here, we report treatment of a child with marginal periodontitis from the age of 3 years-7 years 9 months. No systemic manifestations were noted until 3 years of age, thus the patient had never received a detailed examination or medication related to the disease. Following examinations at our department, we referred the patient to a pediatrician at our university hospital for possible systemic disease, who made a diagnosis of autoimmune neutropenia. Although administration of antibiotics and professional dental care were continued, neutrophil count was not increased and progressive periodontal destruction was observed. Extraction of teeth with poor prognosis was performed and a prosthetic strategy for the missing teeth developed. It is important to recognize that periodontitis along with autoimmune neutropenia can appear in infants, even though the incidence is quite low. Early detection and early treatment of this disease is necessary for delaying progression of periodontitis and optimal occlusal induction of permanent teeth. (C) 2019 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.pdj.2019.06.002

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  • Specific strains of Streptococcus mutans, a pathogen of dental caries, in the tonsils, are associated with IgA nephropathy Reviewed

    Seigo Ito, Taro Misaki, Shuhei Naka, Kaoruko Wato, Yasuyuki Nagasawa, Ryota Nomura, Masatoshi Otsugu, Michiyo Matsumoto-Nakano, Kazuhiko Nakano, Hiroo Kumagai, Naoki Oshima

    Scientific Reports   9 ( 1 )   2019.12

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    DOI: 10.1038/s41598-019-56679-2

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    Other Link: http://www.nature.com/articles/s41598-019-56679-2

  • Identification and molecular characterization of Porphyromonas gulae fimA types among cat isolates. Reviewed International journal

    Iwashita N, Nomura R, Shirai M, Kato Y, Murakami M, Matayoshi S, Kadota T, Shirahata S, Ohzeki L, Arai N, Yasuda J, Yasuda H, Inaba H, Matsumoto-Nakano M, Nakano K, Asai F

    Veterinary microbiology   229   100 - 109   2019.2

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    Porphyromonas gulae, a Gram-negative black-pigmented anaerobe, is one of several major periodontal pathogens of animals. P. gulae isolates from dogs have been classified into three genotypes based on a 41-kDa filamentous appendage (FimA) on the cell surface, which is closely related to virulence in periodontal disease. However, other specific bacterial virulence factors contributing to the aggravation of periodontal disease in cats remain elusive. In the present study, we assessed FimA diversity in P. gulae isolates from cats and examined whether this diversity influenced periodontal condition. The putative amino acid sequences of FimA from 15 P. gulae isolates from 13 cats were classified into three genotypes (types A, B, and C), which showed 95-100% identity and similarity to the fimA types in dogs. The type C isolate showed greater adhesion and invasion properties in periodontal ligament fibroblasts as well as stronger inhibition of scratch closure of the cells compared with type A and B isolates. Next, a PCR-based method for identification of fimA genotype was developed and used to analyze 99 oral swab specimens from cats. High fimA type A detection rates were observed regardless of the periodontal condition, whereas types B and C were frequently detected from subjects with moderate and severe periodontitis, respectively. These results suggest that P. gulae isolates from cats can be classified into three types based on fimA genotype, which may be closely related to virulence in periodontitis.

    DOI: 10.1016/j.vetmic.2018.12.018

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  • Adhesion and invasion of gingival epithelial cells by Porphyromonas gulae. Reviewed International journal

    Inaba H, Nomura R, Kato Y, Takeuchi H, Amano A, Asai F, Nakano K, Lamont RJ, Matsumoto-Nakano M

    PloS one   14 ( 3 )   e0213309   2019

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    Porphyromonas gulae, an animal periodontal pathogen, possess fimbriae classified into three genotypes (A-C) based on the diversity of fimA genes encoding FimA. Accumulating evidence suggests that P. gulae strains with type C fimbriae are more virulent as compared to those with other types. The ability of these organisms to adhere to and invade gingival epithelial cells has yet to be examined. P. gulae showed the greatest levels of adhesion and invasion at a multiplicity of infection of 100 for 90 min. P. gulae type C and some type B strains invaded gingival epithelial cells at significantly greater levels than the other strains, at the same level of efficiency as P. gingivalis with type II fimbriae. Adhesion and invasion of gingival epithelial cells by P. gulae were inhibited by cytochalasin D and sodium azide, indicating the requirements of actin polymerization and energy metabolism for those activities. Invasion within gingival epithelial cells was blocked by staurosporine, whereas those inhibitors showed little effects on adhesion, while nocodazole and cycloheximide had negligible effects on either adhesion or invasion. P. gulae proteases were found to be essential for adhesion and invasion of gingival epithelial cells, while its DNA and RNA, and protein synthesis were unnecessary for those activities. Additionally, α5β1 integrin antibodies significantly inhibited adhesion and invasion by P. gulae. This is the first report to characterize P. gulae adhesion and invasion of human gingival epithelial cells.

    DOI: 10.1371/journal.pone.0213309

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  • Relationship between Streptococcus mutans expressing Cnm in the oral cavity and non-alcoholic steatohepatitis: a pilot study. Reviewed International journal

    Shuichi Tonomura, Shuhei Naka, Keiko Tabata, Tasuku Hara, Kojiro Mori, Saiyu Tanaka, Yoshio Sumida, Kazuyuki Kanemasa, Ryota Nomura, Michiyo Matsumoto-Nakano, Masafumi Ihara, Nobuyuki Takahashi, Kazuhiko Nakano

    BMJ open gastroenterology   6 ( 1 )   e000329   2019

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    Background: Non-alcoholic steatohepatitis (NASH) is a severe state of non-alcoholic fatty liver disease (NAFLD), which is pathologically characterised by steatosis, hepatocyte ballooning, and lobular inflammation. Host-microbial interaction has gained attention as one of the risk factors for NASH. Recently, cnm-gene positive Streptococcus mutans expressing cell surface collagen-binding protein, Cnm (cnm-positive S. mutans), was shown to aggravate NASH in model mice. Here, we assessed the detection rate of cnm-positive S. mutans in oral samples from patients with NASH among NAFLD. Methods: This single hospital cohort study included 41 patients with NAFLD. NASH was diagnosed histologically or by clinical score. The prevalence of cnm-positive S. mutans, oral hygiene and blood tests, including liver enzymes, adipocytokines and inflammatory and fibrosis markers, were assessed in biopsy-proven or clinically suspected NASH among NAFLD. Results: Prevalence of cnm-positive S. mutans was significantly higher in patients with NASH than patients without NASH (OR 3.8; 95% CI 1.02 to 15.5). The cnm-positive S. mutans was related to decreased numbers of naturally remaining teeth and increased type IV collagen 7S level (median (IQR) 10.0 (5.0-17.5) vs 20.0 (5.0-25.0), p=0.06; 5.1 (4.0-7.9) vs 4.4 (3.7-5.3), p=0.13, respectively). Conclusions: Prevalence of cnm-positive S. mutans in the oral cavity could be related to fibrosis of NASH among NAFLD.

    DOI: 10.1136/bmjgast-2019-000329

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  • Dental management of unilateral multiple impacted primary teeth

    Yuki Matsumi, Yuko Morikawa, Eri Yoshida, Setsuyo Morimoto, Sho Yoshida, Tatsushi Matsumura, Seiji Iida, Yukiko Takashima, Shuhei Naka, Michiyo Matsumoto-Nakano

    PEDIATRIC DENTAL JOURNAL   28 ( 3 )   119 - 124   2018.12

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    Impacted primary teeth can be caused by odontogenic tumors such as odontomas, cystic diseases such as dentigerous and eruption cysts, and fibrous hyperplasia of the gingiva, while elimination of those causes reportedly results in normal eruption of primary teeth. We describe the course of a child from the age of 1 year until 4 years 10 months who had primary tooth eruption failure and was treated with dental methods. Although primary teeth expected to spontaneously erupt were followed, there were several on the left side that remained unerupted. We performed a left maxillary and mandibular gingivectomy to closely examine the cause of eruption delay and tooth germ dislocation, as well as attempt to induce eruption of the primary teeth. Based on histopathological results, the diagnosis was fibroma. Surgical procedures did not result in clear improvement of eruption failure. In order to improve masticatory function and aesthetics, the child was fixed with an artificial denture for all primary teeth not expected to erupt. (C) 2018 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.pdj.2018.09.002

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  • Campylobacter rectus in the Oral Cavity Correlates with Proteinuria in Immunoglobulin A Nephropathy Patients Reviewed

    Taro Misaki, Shuhei Naka, Kaoruko Wato, Rina Hatakeyama, Yasuyuki Nagasawa, Seigo Ito, Hiroaki Inaba, Ryota Nomura, Michiyo Matsumoto-Nakano, Kazuhiko Nakano

    Nephron   139 ( 2 )   143 - 149   2018.5

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    Background: Periodontitis-related pathogens, such as Campylobacter or Treponema species, have recently been shown to be associated with immunoglobulin A nephropathy (IgAN). Some strains of Streptococcus mutans, a major pathogen of dental caries, harbour the cnm gene that encodes a collagen-binding protein (Cnm). This has also been demonstrated to be associated with urinary protein levels in IgAN patients. Objectives: The purpose of the present study was to analyse the association of IgAN with C. rectus, Treponema denticola and cnm-positive S. mutans in the oral cavity of humans. Methods: The presence of C. rectus, T. denticola and cnm-positive S. mutans strains in saliva samples of 117 IgAN patients and 56 healthy controls was evaluated by PCR, and the subjects' clinical parameters were analysed. Results: C. rectus was significantly more prevalent in the IgAN group than in the control group (p &lt
    0.05). The C. rectus-positive group was significantly associated with proteinuria in the IgAN group (p &lt
    0.05). In addition, the C. rectus-positive and cnm-positive S. mutans group was shown to be more closely associated with urinary protein levels than the other groups (p &lt
    0.0083). Conclusion: Our results suggest that harbouring C. rectus in the oral cavity could be associated with proteinuria in IgAN patients.

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  • Cell cycle arrest and apoptosis induced by Porphyromonas gingivalis require Jun N-terminal protein kinase- and p53- mediated p38 activation in human trophoblasts Reviewed

    Hiroaki Inaba, Atsuo Amano, Richard J. Lamont, Yukitaka Murakami, Michiyo Matsumoto-Nakano

    Infection and Immunity   86 ( 4 )   2018.4

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    Porphyromonas gingivalis, a periodontal pathogen, has been implicated as a causative agent of preterm delivery of low-birth-weight infants. We previously reported that P. gingivalis activated cellular DNA damage signaling pathways and ERK1/2 that lead to G1 arrest and apoptosis in extravillous trophoblast cells (HTR-8 cells) derived from the human placenta. In the present study, we further examined alternative signaling pathways mediating cellular damage caused by P. gingivalis. P. gingivalis infection of HTR-8 cells induced phosphorylation of p38 and Jun N-terminal protein kinase (JNK), while their inhibitors diminished both G1 arrest and apoptosis. In addition, heat shock protein 27 (HSP27) was phosphorylated through both p38 and JNK, and knockdown of HSP27 with small interfering RNA (siRNA) prevented both G1 arrest and apoptosis. Furthermore, regulation of G1 arrest and apoptosis was associated with p21 expression. HTR-8 cells infected with P. gingivalis exhibited upregulation of p21, which was regulated by p53 and HSP27. These results suggest that P. gingivalis induces G1 arrest and apoptosis via novel molecular pathways that involve p38 and JNK with its downstream effectors in human trophoblasts.

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  • Contributions of Streptococcus mutans Cnm and PA antigens to aggravation of non-alcoholic steatohepatitis in mice Reviewed

    Shuhei Naka, Rina Hatakeyama, Yukiko Takashima, Michiyo Matsumoto-Nakano, Ryota Nomura, Kazuhiko Nakano

    SCIENTIFIC REPORTS   6   36886   2016.11

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    Streptococcus mutans, a major pathogen of dental caries, can cause infective endocarditis after invading the bloodstream. Recently, intravenous administration of specific S. mutans strains was shown to aggravate non-alcoholic steatohepatitis (NASH) in a mouse model fed a high-fat diet. Here, we investigated the mechanism of this aggravation in a NASH mouse model by focusing on the S. mutans cell surface collagen-binding protein (Cnm) and the 190-kDa protein antigen (PA). Mice that were intravenously administered a S. mutans strain with a defect in Cnm (TW871CND) or PA (TW871PD) did not show clinical or histopathological signs of NASH aggravation, in contrast to those administered the parent strain TW871. The immunochemical analyses demonstrated higher levels of interferon-gamma and metallothionein expression in the TW871 group than in the TW871CND and TW871PD groups. Analysis of bacterial affinity to cultured hepatic cells in the presence of unsaturated fatty acids revealed that the incorporation rate of TW871 was significantly higher than those of TW871CND and TW871PD. Together, our results suggest that Cnm and PA are important cell surface proteins for the NASH aggravation caused by S. mutans adhesion and affinity for hepatic cells.

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  • Apple-and Hop-Polyphenols Inhibit Porphyromonas gingivalis-Mediated Precursor of Matrix Metalloproteinase-9 Activation and Invasion of Oral Squamous Cell Carcinoma Cells Reviewed

    Hiroaki Inaba, Motoyuki Tagashira, Tomomasa Kanda, Yukitaka Murakami, Atsuo Amano, Michiyo Matsumoto-Nakano

    JOURNAL OF PERIODONTOLOGY   87 ( 9 )   1103 - 1111   2016.9

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    Background: Recent epidemiologic studies have revealed a significant association between periodontitis and oral squamous cell carcinoma (OSCC). Furthermore, periodontitis is markedly associated with orodigestive cancer mortality, whereas Porphyromonas gingivalis (Pg) infection has been identified as a specific and potentially independent microbial factor related to increased risk of orodigestive cancer death. The authors previously reported that Pg induced the precursor form of matrix metalloproteinase-9 (proMMP-9) production via proteinase-activated receptor (PAR)-related pathways, after which proMMP-9 was activated by gingipains to enhance cellular invasion of SAS cells. In the present study, effects of selected polyphenols as inhibitors of cellular invasion caused by Pg gingipains in SAS cells are examined.
    Methods: OSCC cells were infected with Pg strains including gingipain mutants. To evaluate effects of inhibitors: 1) apple polyphenol (AP); 2) hop bract polyphenol (HBP); 3) high-molecular-weight fractions of HBP (HMW-HBP); 4) low-molecular-weight fractions of HBP (LMW-HBP); 5) epigallocatechin gallate (EGCg); 6) KYT-1 (Arg-gingipain inhibitor); and KYT-36 (Lys-gingipain inhibitor) in combination are used. PAR2 and PAR4 mRNA expressions are examined using real-time reverse transcription polymerase chain reaction, and signaling pathways are evaluated by western blotting analysis.
    Results: KYT-1/KYT-36, AP, HBP, and HMW-HBP significantly inhibited PAR2 and PAR4 mRNA expressions, proMMP-9 activation, and cellular invasion. Furthermore, AP, HBP, and HMW-HBP reduced activation of heat shock protein 27 and Ets1 and nuclear translocation of nuclear factor-kappa B, whereas EGCg and LMW-HBP did not.
    Conclusion: These results suggest that AP, HBP, HMW-HBP are potent inhibitors of proMMP-9 activation and cellular invasion mediated with Pg in OSCC cells.

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  • Characterization of the dextran-binding domain in the glucan-binding protein C of Streptococcus mutans Reviewed

    Y. Takashima, K. Fujita, A. C. Ardin, K. Nagayama, R. Nomura, K. Nakano, M. Matsumoto-Nakano

    JOURNAL OF APPLIED MICROBIOLOGY   119 ( 4 )   1148 - 1157   2015.10

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    Aims: Streptococcus mutans produces multiple glucan-binding proteins (Gbps), among which GbpC encoded by the gbpC gene is known to be a cell-surface-associated protein involved in dextran-induced aggregation. The purpose of the present study was to characterize the dextran-binding domain of GbpC using bioinformatics analysis and molecular techniques.
    Methods and Results: Bioinformatics analysis specified five possible regions containing molecular binding sites termed GB1 through GB5. Next, truncated recombinant GbpC (rGbpC) encoding each region was produced using a protein expression vector and five deletion mutant strains were generated, termed CDGB1 through CDGB5 respectively. The dextran-binding rates of truncated rGbpC that included the GB1, GB3, GB4 and GB5 regions in the upstream sequences were higher than that of the construct containing GB2 in the downstream region. In addition, the rates of dextran-binding for strains CDGB4 and CD1, which was entire gbpC deletion mutant, were significantly lower than for the other strains, while those of all other deletion mutants were quite similar to that of the parental strain MT8148. Biofilm structures formed by CDGB4 and CD1 were not as pronounced as that of MT8148, while those formed by other strains had greater density as compared to that of CD1.
    Conclusion: Our results suggest that the dextran-binding domain may be located in the GB4 region in the interior of the gbpC gene.
    Significance and Impact of the Study: Bioinformatics analysis is useful for determination of functional domains in many bacterial species.

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  • Short communication: Distribution of Porphyromonas gulae fimA genotypes in oral specimens from dogs with mitral regurgitation Reviewed

    Mitsuyuki Shirai, Ryota Nomura, Yukio Kato, Masaru Murakami, Chihiro Kondo, Soraaki Takahashi, Yoshie Yamasaki, Michiyo Matsumoto-Nakano, Nobuaki Arai, Hidemi Yasuda, Kazuhiko Nakano, Fumitoshi Asai

    RESEARCH IN VETERINARY SCIENCE   102   49 - 52   2015.10

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    Porphyromonas gulae, a suspected pathogen for periodontal disease in dogs, possesses approximately 41-kDa fimbriae (FimA) that are encoded by the fimA gene. In the present study, the association of fimA genotypes with mitral regurgitation (MR) was investigated. Twenty-five dogs diagnosed with MR (age range 6-13 years old, average 10.8 years) and 32 healthy dogs (8-15 years old, average 10.8 years) were selected at the participating clinics in a consecutive manner during the same time period. Oral swab specimens were collected from the dogs and bacterial DNA was extracted, then polymerase chain reaction analysis was performed using primers specific for each fimA genotype, with the dominant genotype determined. The rate for genotype C dominant specimens was 48.0% in the MR group, which was significantly higher than that in the control group (18.8%) (P &lt;0.05). These results suggest that P. gulae fimA genotype C is associated with MR. (C) 2015 Elsevier Ltd. All rights reserved.

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  • Contribution of glucan-binding protein A to firm and stable biofilm formation by Streptococcus mutans Reviewed

    Y. Matsumi, K. Fujita, Y. Takashima, K. Yanagida, Y. Morikawa, M. Matsumoto-Nakano

    MOLECULAR ORAL MICROBIOLOGY   30 ( 3 )   217 - 226   2015.6

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    Glucan-binding proteins (Gbps) of Streptococcus mutans, a major pathogen of dental caries, mediate the binding of glucans synthesized from sucrose by the action of glucosyltransferases (GTFs) encoded by gtfB, gtfC, and gtfD. Several stress proteins, including DnaK and GroEL encoded by dnaK and groEL, are related to environmental stress tolerance. The contribution of Gbp expression to biofilm formation was analyzed by focusing on the expression levels of genes encoding GTFs and stress proteins. Biofilm-forming assays were performed using GbpA-, GbpB-, and GbpC-deficient mutant strains and the parental strain MT8148. The expression levels of gtfB, gtfC, gtfD, dnaK, and groEL were evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Furthermore, the structure of biofilms formed by these Gbp-deficient mutant strains was observed using confocal laser scanning microscopy (CLSM). Biofilm-forming assay findings demonstrated that the amount formed by the GbpA-deficient mutant strain (AD1) was nearly the same as that by the parental strain, while the GbpB- and GbpC-deficient mutant strains produced lower amounts than MT8148. Furthermore, RT-qPCR assay results showed that the expressions of gtfB, dnaK, and groEL in AD1 were elevated compared with MT8148. CLSM also revealed that the structure of biofilm formed by AD1 was prominently different compared with that formed by the parental strain. These results suggest that a defect in GbpA influences the expression of genes controlling biofilm formation, indicating its importance as a protein for firm and stable biofilm formation.

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  • Variation of expression defects in cell surface 190-kDa protein antigen of Streptococcus mutans Reviewed

    Jinthana Lapirattanakul, Ryota Nomura, Michiyo Matsumoto-Nakano, Ratchapin Srisatjaluk, Takashi Ooshima, Kazuhiko Nakano

    INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY   305 ( 3 )   383 - 391   2015.5

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    Streptococcus mutans, which consists of four serotypes, c, e, f, and k, possesses a 190-kDa cell surface protein antigen (PA) for initial tooth adhesion. We used Western blot analysis to determine PA expression in 750 S. mutans isolates from 150 subjects and found a significantly higher prevalence of the isolates with PA expression defects in serotypes f and k compared to serotypes c and e. Moreover, the defect patterns could be classified into three types; no PA expression on whole bacterial cells and in their supernatant samples (Type N1), PA expression mainly seen in supernatant samples (Type N2), and only low expression of PA in the samples of whole bacterial cells (Type W). The underlying reasons for the defects were mutations in the gene encoding PA as well as in the transcriptional processing of this gene for Type N1, defects in the sortase gene for Type N2, and low mRNA expression of PA for Type W. Since cellular hydrophobicity and phagocytosis susceptibility of the PA-defective isolates were significantly lower than those of the normal expression isolates, the potential implication of such defective isolates in systemic diseases involving bacteremia other than dental caries was suggested. Additionally, multilocus sequence typing was utilized to characterize S. mutans clones that represented a proportion of isolates with PA defects of 65-100%. Therefore, we described the molecular basis for variation defects in PA expression of S. mutans. Furthermore, we also emphasized the strong association between PA expression defects and serotypes f and k as well as the clonal relationships among these isolates. (C) 2015 Elsevier GmbH. All rights reserved.

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  • Contribution of the Interaction of Streptococcus mutans Serotype k Strains with Fibrinogen to the Pathogenicity of Infective Endocarditis Reviewed

    Ryota Nomura, Masatoshi Otsugu, Shuhei Naka, Noboru Teramoto, Ayuchi Kojima, Yoshinori Muranaka, Michiyo Matsumoto-Nakano, Takashi Ooshima, Kazuhiko Nakano

    INFECTION AND IMMUNITY   82 ( 12 )   5223 - 5234   2014.12

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    Streptococcus mutans, a pathogen responsible for dental caries, is occasionally isolated from the blood of patients with bacteremia and infective endocarditis (IE). Our previous study demonstrated that serotype k-specific bacterial DNA is frequently detected in S. mutans-positive heart valve specimens extirpated from IE patients. However, the reason for this frequent detection remains unknown. In the present study, we analyzed the virulence of IE from S. mutans strains, focusing on the characterization of serotype k strains, most of which are positive for the 120-kDa cell surface collagen-binding protein Cbm and negative for the 190-kDa protein antigen (PA) known as SpaP, P1, antigen I/II, and other designations. Fibrinogen-binding assays were performed with 85 clinical strains classified by Cbm and PA expression levels. The Cbm(+)/PA(-) group strains had significantly higher fibrinogen-binding rates than the other groups. Analysis of platelet aggregation revealed that SA31, a Cbm(+)/PA(-) strain, induced an increased level of aggregation in the presence of fibrinogen, while negligible aggregation was induced by the Cbm-defective isogenic mutant SA31CBD. A rat IE model with an artificial impairment of the aortic valve created using a catheter showed that extirpated heart valves in the SA31 group displayed a prominent vegetation mass not seen in those in the SA31CBD group. These findings could explain why Cbm(+)/PA(-) strains are highly virulent and are related to the development of IE, and the findings could also explain the frequent detection of serotype k DNA in S. mutans-positive heart valve clinical specimens.

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  • Identification and Functional Analysis of an Ammonium Transporter in Streptococcus mutans Reviewed

    Arifah Chieko Ardin, Kazuyo Fujita, Kayoko Nagayama, Yukiko Takashima, Ryota Nomura, Kazuhiko Nakano, Takashi Ooshima, Michiyo Matsumoto-Nakano

    PLOS ONE   9 ( 9 )   e107569   2014.9

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    Streptococcus mutans, a Gram-positive bacterium, is considered to be a major etiologic agent of human dental caries and reported to form biofilms known as dental plaque on tooth surfaces. This organism is also known to possess a large number of transport proteins in the cell membrane for export and import of molecules. Nitrogen is an essential nutrient for Grampositive bacteria, though alternative sources such as ammonium can also be utilized. In order to obtain nitrogen for macromolecular synthesis, nitrogen-containing compounds must be transported into the cell. However, the ammonium transporter in S. mutans remains to be characterized. The present study focused on characterizing the ammonium transporter gene of S. mutans and its operon, while related regulatory genes were also analyzed. The SMU. 1658 gene corresponding to nrgA in S. mutans is homologous to the ammonium transporter gene in Bacillus subtilis and SMU. 1657, located upstream of the nrgA gene and predicted to be glnB, is a member of the PII protein family. Using a nrgA-deficient mutant strain (NRGD), we examined bacterial growth in the presence of ammonium, calcium chloride, and manganese sulfate. Fluorescent efflux assays were also performed to reveal export molecules associated with the ammonium transporter. The growth rate of NRGD was lower, while its fluorescent intensity was much higher as compared to the parental strain. In addition, confocal laser scanning microscopy revealed that the structure of biofilms formed by NRGD was drastically different than that of the parental strain. Furthermore, transcriptional analysis showed that the nrgA gene was co-transcribed with the glnB gene. These results suggest that the nrgA gene in S. mutans is essential for export of molecules and biofilm formation.

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  • Role of ABC transporter proteins in stress responses of Streptococcus mutans. Reviewed

    Nagayama K, Fujita K, Takashima Y, Ardin AC, Ooshima T, Matsumoto-Nakano M

    Oral health and dental management   13 ( 2 )   359 - 365   2014.6

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  • Black pigmentation in primary dentition: Case report and literature review Reviewed

    Yukiko Takashima, Yuki Matsumi, Yoshie Yamasaki, Keiko Hirano, Kanako Yanagida, Kazuyo Fujita, Michiyo Matsumoto-Nakano

    Pediatric Dental Journal   24 ( 3 )   184 - 188   2014

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    Black tooth staining is an extrinsic discoloration found in both primary and permanent dentition, and seen as dark pigmented lines extending to the gingival margin or an incomplete coalescence of dark dots that rarely extend beyond the cervical third of the crown. An association between black tooth staining and Actinomyces bacterial strains has been reported, while black-pigmented bacteria associated with such staining are known to be harbored in the oral cavity. Prevotella intermedia and Prevotella nigrescens are black-pigmented bacteria known to be dependent on the heme portion of hemoglobin as an iron source required for their growth. Recently, developments in molecular biological techniques have enabled rapid and easy detection of periodontopathic bacterial species using bacterial DNA extracted from oral specimens, such as plaque and saliva. Here, we report a case of black pigmentary deposition identified on all teeth of a 2-year-old girl, as well as the results of analysis of the distribution of oral bacteria in saliva and plaque specimens obtained from the patient using a molecular biological technique. In addition, a literature search found a case of disease related to the oral bacteria detected in our patient. We concluded that the bacteria detected in this case may have a strong relationship with black pigmentation, although the route of bacterial infection and cause of staining remain to be elucidated.

    DOI: 10.1016/j.pdj.2014.09.003

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  • Correlation of age with distribution of periodontitis-related bacteria in Japanese dogs Reviewed

    Norihiko Hirai, Mitsuyuki Shirai, Yukio Kato, Masaru Murakami, Ryota Nomura, Yoshie Yamasaki, Soraaki Takahashi, Chihiro Kondo, Michiyo Matsumoto-Nakano, Kazuhiko Nakano, Fumitoshi Asai

    Journal of Veterinary Medical Science   75 ( 7 )   999 - 1001   2013

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    We analyzed the distribution of 11 periodontitis-related bacterial species in dental plaque collected from 176 Japanese dogs divided into young (less than 2 years of age), middle-aged (2-7 years of age) and elderly (more than 8 years of age) groups using a polymerase chain reaction method. Clinical examination revealed that no dogs in the young group were affected by periodontitis, whereas the rates for gingivitis and periodontitis were high in the middle-aged and elderly groups. In addition, the total numbers of bacterial species in the middle-aged and elderly groups were significantly greater than in the young group. Our findings suggest that age is an important factor associated with the distribution of periodontitis-related bacteria and periodontal conditions in dogs. © 2013 The Japanese Society of Veterinary Science.

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  • Diversity of Fimbrillin among Porphyromonas gulae Clinical Isolates from Japanese Dogs Reviewed

    Ryota Nomura, Mitsuyuki Shirai, Yukio Kato, Masaru Murakami, Kazuhiko Nakano, Norihiko Hirai, Tetsuya Mizusawa, Shuhei Naka, Yoshie Yamasaki, Michiyo Matsumoto-Nakano, Takashi Ooshima, Fumitoshi Asai

    JOURNAL OF VETERINARY MEDICAL SCIENCE   74 ( 7 )   885 - 891   2012.7

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    Porphyromonas gulae, a gram-negative black-pigmented anaerobe, is a pathogen for periodontitis in dogs. An approximately 41-kDa fimbrial subunit protein (FimA) encoded by fimA is regarded as associated with periodontitis. In the present study, the fimA genes of 17 P. gulae strains were sequenced, and classified into two major types. The generation of phylogenetic trees based on the deduced amino acid sequence of FimA of P. gulae strains along with sequences from several strains of Porphyromonas gingivalis, a major cause of human periodontitis, revealed that the two types of FimA (types A and B) of P. gulae were similar to type I FimA and types II and III FimA of P. gingivalis, respectively. A PCR system for classification was established based on differences in the nucleotide sequences of the fimA genes. Analysis of 115 P. gulae-positive oral swab specimens from dogs revealed that 42.6%, 22.6%, and 26.1% of them contained type A, type B, and both type A and B fimA genes, respectively. Experiments with a mouse abscess model demonstrated that the strains with type B fimA caused significantly greater systemic inflammation than those with type A. These results suggest that the FimA proteins of P. gulae are diverse with two major types and that strains with type B fimA could be more virulent.

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  • Molecular interaction of alanine-rich and proline-rich regions of cell surface protein antigen PAc in Streptococcus mutans Reviewed

    Matsumoto-Nakano M, Tsuji M, Amano A, Ooshima T

    Oral Microbiology and Immunology   2008.8

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  • Role of bacteriocin immunity proteins in the antimicrobial sensitivity of Streptococcus mutans Reviewed

    Michiyo Matsumoto-Nakano, Howard K. Kuramitsu

    JOURNAL OF BACTERIOLOGY   188 ( 23 )   8095 - 8102   2006.12

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    Bacteria utilize quorum-sensing systems to modulate environmental stress responses. The quorum-sensing system of Streptococcus mutans is mediated by the competence-stimulating peptide (CSP), whose precursor is encoded by the comC gene. A comC mutant of strain GS5 exhibited enhanced antimicrobial sensitivity to a wide variety of different agents. Since the addition of exogenous CSP did not complement this phenotype, it was determined that the increased tetracycline, penicillin, and triclosan sensitivities resulted from repression of the putative bacteriocin immunity protein gene, bip, which is located immediately upstream from comC. We further demonstrated that the inactivation of bip or smbG, another bacteriocin immunity protein gene present within the smb operon in S. mutans GS5, affected sensitivity to a variety of antimicrobial agents. Furthermore, both the bip and smbG genes were upregulated in the presence of low concentrations of antibiotics and were induced during biofilm formation relative to in planktonic cells. These results suggest, for the first time, that the antimicrobial sensitivity of a bacterium can be modulated by some of the putative bacteriocin immunity proteins expressed by the organism. The implications of these observations for the evolution of bacteriocin immunity protein genes as well as for potential new chemotherapeutic strategies are discussed.

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Books

  • 最新歯科衛生士教本 小児歯科 第2版

    ( Role: Joint author ,  小児歯科における患者との対応法)

    医歯薬出版  2021.3 

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    Total pages:211   Language:Japanese

  • 子どものみかたBOOK

    ( Role: Joint author ,  乳歯におけるランパントカリエスの特徴と治療法)

    デンタルダイヤモンド社  2021.3  ( ISBN:978-4-88510-493-0

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    Total pages:175   Language:Japanese

  • 身近な臨床・これからの歯科医のための臨床講座

    ( Role: Contributor)

    日本歯科医師会  2021.2 

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    Language:Japanese

  • 子どもの病気・けがNOTE

    ( Role: Contributor ,  その他の歯と口の病気(口内炎と正中離開))

    東山書房  2020.11 

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    Language:Chinese

  • 小児歯科はじめましょう

    ( Role: Joint author ,  小児の歯内療法)

    デンタルダイヤモンド社  2020.6 

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    Total pages:209   Language:Japanese Book type:Textbook, survey, introduction

  • 小児救急治療ガイドライン

    ( Role: Joint author)

    2020 

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    Language:Japanese Book type:Scholarly book

  • 乳幼児の口と歯の健診ガイド

    ( Role: Joint author ,  乳幼児の航空健康診査ポイント)

    医歯薬出版  2019.6 

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    Language:Japanese Book type:Textbook, survey, introduction

  • 小児歯科のレベルアップ&ヒント

    ( Role: Joint author ,  侵襲性歯周炎)

    デンタルダイヤモンド社  2019.6  ( ISBN:978-4-88510-436-7

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Presentations

  • Porphyromonas gulae 線毛のバイオフィルム形成能と遺伝子多型の関連

    吉田 翔, 稲葉 裕明, 仲野 道代

    第 42 回岡山⻭学会総会・学術集会  2021.11.28 

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  • 乳⻭の早期脱落が認められた小児と健常児の口腔細菌叢の比較

    宮井 由記子, 仲 周平, 仲野 道代

    第 42 回岡山⻭学会総会・学術集会  2021.11.28 

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Research Projects

  • 口腔細菌叢のメタゲノム解析による非アルコール性脂肪肝炎発症機序解明と新規予防戦略

    Grant number:21K19604  2021.07 - 2024.03

    日本学術振興会  科学研究費助成事業 挑戦的研究(萌芽)  挑戦的研究(萌芽)

    仲野 道代

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    Grant amount:\6500000 ( Direct expense: \5000000 、 Indirect expense:\1500000 )

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  • 骨系統疾患患者の歯科病態の包括的検証と新規治療薬の歯科領域における評価

    Grant number:21K10183  2021.04 - 2024.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    大川 玲奈, 鋸屋 侑布子, 柿本 直也, 中元 崇, 仲野 道代

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    Grant amount:\4030000 ( Direct expense: \3100000 、 Indirect expense:\930000 )

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  • 歯周病レッドコンプレックスとIgA腎症発症進展機序解明と新規治療法の開発

    Grant number:21K08242  2021.04 - 2024.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    長澤 康行, 仲野 道代, 野村 良太

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

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  • 口腔内細菌叢の網羅的解析による口腔粘膜障害への臨床アプローチ

    Grant number:21K10185  2021.04 - 2024.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    平野 慶子, 仲野 道代, 後藤 花奈

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    Grant amount:\4160000 ( Direct expense: \3200000 、 Indirect expense:\960000 )

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  • 膜タンパクをターゲットとした新たな口腔バイオフィルム制御法の確立

    Grant number:20H03897  2020.04 - 2023.03

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    仲野 道代, 仲 周平, 稲葉 裕明

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    Grant amount:\17290000 ( Direct expense: \13300000 、 Indirect expense:\3990000 )

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  • 歯科領域からの革新的治療法の開発を目指した口腔細菌に起因するIgA腎症の病態解明

    Grant number:20K10225  2020.04 - 2023.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    仲 周平, 仲野 和彦, 仲野 道代

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

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  • IgA腎症患者の口腔検体と腎生検・摘出扁桃検体の歯科ー腎臓内科による学際的検討

    Grant number:19K10098  2019.04 - 2022.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    三崎 太郎, 仲野 和彦, 長澤 康行, 仲野 道代

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

    本研究はIgA腎症をはじめとする慢性腎臓病と口腔内疾患との関連を検討する。
    ●う蝕原生細菌cnm 陽性S. mutans株とIgA腎症との関連についての病理的(扁桃)検討を行った。【目的】Cnm陽性S. mutansが扁桃を介してIgA腎症発症に関わっている可能性を検討する。【方法】腎生検で診断されたIgA腎症患者64人と慢性扁桃炎患者40人の摘出扁桃切片を, リコンビナントCnmタンパクを抗原として作製したポリクローナル抗体を用いて免疫染色し、Cnmの陽性率と臨床データとの関連を検討した。【結果】IgA腎症群では、慢性扁桃炎群と比較してCnm陽性S. mutansの陽性率が有意に高値であった(p < 0.05)。さらに、 IgA腎症群において、Cnm陽性S. mutans扁桃保菌者が非保菌者に比べ、有意に蛋白尿が多かった(p < 0.05)。【結論】扁桃におけるCnm陽性S .mutansはIgA腎症発症に関わり、患者の蛋白尿と関連する。以上はScientific Reports 2019に報告した。
    ●透析患者のう蝕の研究を行った。“透析患者の口腔状態は悪く、様々な全身の合併症に影響している”と仮説を立てた。【方法】透析患者80人と健常者76人のう蝕経験歯数(DMFT)と地域歯周疾患指数(CPI)を算定し、臨床データとの関連を検討した。【結果】透析患者群では健常群と比較して、DMFTが24以上である対象が有意に多かった (p < 0.05)。また、透析患者群内の比較では、DMFTが24以上の群では24以下の群と比べ脈圧差が有意に大きく(p < 0.05)、心疾患の既往率が高値であった (p < 0.05)。CPIは有意差を認めなかった。【結論】透析患者では健常者に比べてう蝕が重篤であり、そのことが動脈硬化と関連している可能性がある。以上はPLOS ONE2019に報告した。

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  • Elucidation of the relationship between P. gulae infection and periodontitis onset mechanism

    Grant number:17K11612  2017.04 - 2020.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Inaba Hiroaki

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    Grant amount:\4550000 ( Direct expense: \3500000 、 Indirect expense:\1050000 )

    P. gulae type C and some type B strains invaded gingival epithelial cells at significantly greater levels than the other strains, at the same level of efficiency as P. gingivalis with type II fimbriae. Adhesion and invasion of
    gingival epithelial cells by P. gulae were inhibited by cytochalasin D and sodium azide, indicating the requirements of actin polymerization and energy metabolism for those activities. Invasion within gingival epithelial cells was blocked by staurosporine, while nocodazole and cycloheximide had negligible effects on either adhesion or invasion. P. gulae proteases were found to be essential for adhesion and invasion of gingival epithelial cells, while its DNA and RNA, and protein synthesis were unnecessary for those activities. Additionally, α5β1 integrin antibodies significantly inhibited adhesion and invasion by P. gulae. This is the first report to characterize P. gulae adhesion and invasion of human gingival epithelial cells.

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  • Dental caries prevention methods using GbpC glucan-binding domain in S. mutans.

    Grant number:17K11961  2017.04 - 2020.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    TAKASHIMA YUKIKO

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    Grant amount:\4420000 ( Direct expense: \3400000 、 Indirect expense:\1020000 )

    Streptococcus mutans, a major pathogenic bacterium involved in development of dental caries, produces multiple glucan-binding proteins (Gbps) that bind to glucan and other molecules. In our previous study, bioinformatics analysis results identified a glucan-binding domain (GBD) located in the middle of the gbpC encoding GbpC. In addition, an MT8148 strain deficient of GBD was constructed to examine adherence to human umbilical vein epithelial cells (HUVECs). Adhesion to HUVECs by the deficient strain was reduced as compared to that of the parental strain. In this study, we examined the inhibitory effects of an antibody against the peptide encoded by GBD on induction of dental caries using a rat caries model. The caries score in the group that receive adminisration of the antibody was decreased as compared to that of control group. These results suggest that inhibition of the function of the binding domain of GbpC is effective to prevent its invovlvement in dental caries development.

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  • ABC transporter function in biofilm formation and its application for dental caries prevention

    Grant number:16H05550  2016.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    NAKANO Michiyo

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    Grant amount:\16900000 ( Direct expense: \13000000 、 Indirect expense:\3900000 )

    Streptococcus mutans possesses a large number of transporters with import/export functions, including the PII protein family that is widely distributed among bacterial species. We constructed and examined a glutamine ABC transporter (GlnP) deficient mutant strain. Biofilm formed by GlnP-deficient mutant strain was remarkably different as compared to that produced by the parental strain. GlnP-deficient mutant strain also showed a reduced number of imported molecules and lower acid tolerance ability. The S. mutans signaling system is mediated by the competence-stimulating peptide (CSP), whose precursor is encoded by the comC gene. We analyzed nrgA gene expression regulation by CSP and found that GlnP and PII protein gene expressions were decreased in comC-deficient mutant strains. Together, these results suggest that GlnP is associated with the S. mutans substrate transport and signaling system, and involved in biofilm formation.

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  • Clinical and basic investigations for proposal regarding chemotherapy use in pediatric dentistry

    Grant number:16K15838  2016.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    NAKANO MICHIYO

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    Grant amount:\3380000 ( Direct expense: \2600000 、 Indirect expense:\780000 )

    Several case reports have described dental anomalies in permanent teeth caused by chemotherapy administration during tooth germ development. In the present study, clinical and basic examinations were performed to investigate the correlation between chemotherapy and dental abnormalities in children. For the clinical research portion, detailed of 39 patients were collected and dental abnormalities detemined by vieweing orthopantomograph images, which showed their occurrence in 32 cases, with atypical root formation most commonly noted. To investigate the effects of chemotherapy on dental development, immunohistological examinations of tooth germs in a mouse model treated with cyclophosphamide were done. Cytokeratin and vimentin expression levels were decreased in a cyclophosphamide dose-dependent manner, and defective root formation was seen. These results suggest that chemotherapy is strongly correlated with dental abnormalities.

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  • Clinical effects of hematopoietic stem cell transplantation on oral microflora using microbiological analysis

    Grant number:15K11366  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Hirano keiko

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    Grant amount:\4810000 ( Direct expense: \3700000 、 Indirect expense:\1110000 )

    The oral condition of pediatric patients with cancer worsens following hematopoietic stem cell transplantation (HSCT), with oral mucositis, caused by environmental fluctuations in the oral cavity that involve oral microflora, one of the major side effects of that procedure. For the present study, saliva and plaque samples were collected from patients before and after undergoing HSCT. Genomic DNA was then extracted from those samples and microbiological examinations using PCR assays were performed. The frequency of occurrence of oral streptococci did not change before and after, while that of periodontal bacteria was increased following the procedure. In addition, the rate of detection of Lactobacillus was 40% before and increased to 90% after HSCT. In a previous study, co-existing Lactobacillus and mutans streptococci in the oral cavity were shown to cause severe caries. The present results suggest that oral mucositis and severe caries are induced by oral microflora alterations.

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  • Basic and clinical approaches for dental problems associated with skeletal diseases

    Grant number:15K11364  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    OKAWA RENA, NAKANO Kazuhiko, OZONO Keiichi, KITAOKA Taichi, NAKANO Michiyo

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )

    The purpose of this study was to investigate dental problems related to skeletal diseases with basic and clinical approaches. A nationwide dental survey revealed that dentinogenesis imperfecta is a major dental problem occurring in 60% of patients affected by osteogenesis imperfecta. In those patients, a permanent successor often emerges into the oral cavity without resorption of the root of the corresponding primary tooth due to dislocation by that successor. However, the present survey found that bisphosphonate treatment does not need to be interrupted in such cases when the primary tooth is extracted. Early exfoliation was recognized in not only primary but also permanent teeth in a patient with hypophosphatasia. In another hypophosphatasia patient who received enzyme replacement therapy 1 day after birth, cementum formation was detected. Furthermore, gene therapy was demonstrated to improve dental manifestations in model mice with hypophosphatasia.

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  • Construction of global standard molecular epidemiological method for identification of the children at risk for severe dental caries

    Grant number:15H05300  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    Nakano Kazuhiko, LAPIRATTANAKUL Jinthana

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    Grant amount:\15730000 ( Direct expense: \12100000 、 Indirect expense:\3630000 )

    Saliva specimens were taken from 3- and 4-year-old Thai children attending a kindergarten and nursery school in Bangkok, Thailand, from which Streptococcus mutans and Lactobacillus species were isolated using selective medium for each. Findings obtained from the S. mutans isolates provided new data to be added to a previously constructed multilocus sequence typing (MLST) scheme, which revealed the possibility of the correlation of a specific group of strains with clinical findings related to dental caries. As for the Lactobacillus species, Lactobacillus fermentus was shown to be associated with severe dental caries, thus several strains were classified using an MLST scheme, with novel sequence types revealed.

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  • 乳酸菌による新たな齲蝕発生メカニズムの解析

    Grant number:15K11365  2015.04 - 2017.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    藤田 一世, 仲野 道代

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    Grant amount:\4810000 ( Direct expense: \3700000 、 Indirect expense:\1110000 )

    近年、小児の唾液中に存在する齲蝕原性細菌であるStreptococcus mutans菌数は減少する傾向にあり、齲蝕があるにも関わらず、S. mutansが検出されない小児が増加している。そこで、口腔内には、乳幼児の重度齲蝕において重要な位置を占めていると考えられている乳酸菌群が存在することから、本研究の目的は、乳酸菌が関連する新たな齲蝕発生メカニズムを明らかにすることである。
    岡山大学医歯薬学総合研究科倫理委員会承認のもと、岡山大学病院小児歯科を受診された患児のうち、齲蝕を認める患児の唾液を採取し乳酸菌を分離同定し、その齲蝕原性について検討を加えた。結果として乳酸菌単独では、スクロース依存性平滑面付着能はS. mutansと比較すると低下していたが、S. mutansと混合して培養した場合、乳酸菌単一で培養した時と比較して、付着率が有意に高くなった。また、バイオフィルムの構造を観察したところ、乳酸菌は固層表面に単独でもバイオフィルムを形成することが可能であることが明らかとなった。さらに、乳酸菌単一のバイオフィルと比較して、S. mutansと混合して培養した場合のバイオフィルムでは、密度が高くなり、高さも増加していた。そこで、培養中に乳酸菌を作用させたS. mutansから全RNAを抽出し、Real-Time Reverse transcription PCRにより、S mutansのグルカン合成酵素であるグルコシルトランスフェラーゼの発現を調べたところ、乳酸菌を作用させていないS. mutansと比較して有意に発現の上昇が認められた。これらのことから、乳酸菌の存在は、齲蝕の発生に大きく関与している可能性が示唆された。
    一方で口腔内より分離された乳酸菌のコラーゲン結合を調べたところ、S. mutansと比較してコラーゲン結合能が顕著に高い乳酸菌の存在が明らかとなった。この結果は、乳酸菌の存在は、象牙質齲蝕の進行に関連している可能性が示唆された。

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  • Establishment of evidence of effectiveness of amoxicillin in the subjects at risk for infective endocarditis

    Grant number:25463177  2013.04 - 2016.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    NEMOTO Hirotoshi, NAKANO Michiyo

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    Grant amount:\5070000 ( Direct expense: \3900000 、 Indirect expense:\1170000 )

    Analyses of saliva specimens collected from healthy mothers and their children revealed that the prevalence rate of amoxicillin-resistant oral streptococci was approximately 5%, while that of clindamycin-resistant oral streptococci was approximately 30%. Other findings revealed resistance to other antibiotics by these strains as well as their possible transmission from mother to child. Thereafter, analyses of obtained oral specimens were performed to investigate the presence of amoxicillin-resistant strains in subjects at risk for infective endocarditis. However, we were unable to collect an adequate number of samples in order to analyze with statistical significance and consider that a large-scale study is necessary to perform this research.

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  • Relationship of Streptococcus mutans bacteriocin production with formation of biofilm

    Grant number:25463178  2013.04 - 2016.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Nagayama Kayoko, NAKANO Michiyo

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    Grant amount:\5070000 ( Direct expense: \3900000 、 Indirect expense:\1170000 )

    Streptococcus mutans, known as a primary causative agent of dental caries, produces bacteriocins that inhibit the growth of similar or closely related oral bacteria. The purpose of the present study was to examine the functions of 2 peptide bacteriocins, SmbA and NlmA, as well as the correlation between production of bacteriocin and biofilm formation. The amount of bacteriocin produced by an SmbA-deficient mutant strain was lower as compared to that by an NlmA-deficient mutant strain, while biofilm formation by NlmA-deficient mutant strain was lower than that by the SmbA-deficient mutant strain. In addition, both bacteriocin production and biofilm formation were altered in the presence of Streptococcus gordonii. These results suggest that the presence of strains prossessing bacteriocins, such as SmbA and NlmA may be dominant in biofilm due to their effects on other oral streptococci. In addition, bacteriocins might have a role in competition with other oral streptococci.

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  • Mechanism of aggravation of periodontitis caused by periodontitis-related bacteria transmitted from companion animals

    Grant number:25670873  2013.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    NOMURA Ryota, NAKANO Michiyo, ASAI Fumitoshi

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    Grant amount:\3770000 ( Direct expense: \2900000 、 Indirect expense:\870000 )

    Information regarding transmission of periodontitis-related bacterial species between dogs and their owners is limited. In the present study, we detected periodontitis-related species in both dogs and their owners including Porphyromonas gulae, known to be a major bacterial pathogen of periodontitis in dogs. P. gulae possesses approximately 41-kDa filamentous appendages (FimA), which have been classified into three major genotypes; A, B, and C. Our results showed that P. gulae with FimA genotype C was associated with mitral regurgitation in dogs.

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  • Development of substrate with recombinase A to prevent dental caries

    Grant number:25670874  2013.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    NAKANO MICHIYO

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    Grant amount:\3770000 ( Direct expense: \2900000 、 Indirect expense:\870000 )

    Streptococcus mutans produces glucosyltransferases (GTFs), with recombinase A (RecA) is required for homologous recombination. Previously, we isolated several S. mutans strains with a smooth colony morphology, which also demonstrated characteristics thought to be derived from GTFBC fusion. As for their biological characteristics, biofilm formation was reduced as compared to strains with no fusion. In this study, we artificially produced GTFBC fusion strains by adding recombinant RecA (rRecA), which showed low cariogenic properties. Also, gel-shift assay results indicated that rRecA may bind to the promoter sequences of gtfB and C, encoding GTFB and C. However, gtfB expression was increased when the rRecA was added to growing cells. We speculate that RecA has two functions with gtf genes, though further investigation is needed. RecA may have important roles in gtf expression related to biofilm formation, which may lead to development of a substrate to prevent dental caries.

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  • Functional analyses of expression and regulation of glucan-binding protein B in Streptococcus mutans

    Grant number:24593089  2012.04 - 2015.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    FUJITA Kazuyo, NAKANO Michiyo

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    Grant amount:\5330000 ( Direct expense: \4100000 、 Indirect expense:\1230000 )

    Streptococcus mutans is known to synthesize at least 4 different glucan-binding proteins (Gbps), of which GbpB has been purified and shown to be immunologically distinct from the other Gbps. GbpB is considered to play an important role in cell-wall construction. The mreC and mreD, encoding MreC and MreD, respectively, are essential proteins for lateral peptidoglycan synthesis are located upstream of the gbpB encoding GbpB. The purpose of the present study was to analyze the expression of mreC and mreD with focus on GbpB expression patterns. Transcriptional analysis showed that mreC, mreD, and gbpB constituted an operon. Next, MreC- and MreD-deficient mutant strains were constructed by insertional inactivation of the corresponding genes, and the expression level of gbpB was examined. gbpB expression was elevated in the MreC-deficient mutants and reduced in the MreD-deficient mutants. These results suggest that the mreC and mreD genes participate in regulation of gbpB gene expression.

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  • Functional analysis of signal transduction system involving membrane transporters in Streptococcus mutans

    Grant number:23390473  2011.04 - 2014.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    NAKANO Michiyo, FUJITA Kazuyo, OSHIMA Takashi

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    Grant amount:\19240000 ( Direct expense: \14800000 、 Indirect expense:\4440000 )

    Streptococcus mutans metabolizes carbohydrates for adherence to and formation of biofilm on tooth surfaces, which allows the pathogen to tolerate rapid and frequent environmental fluctuations, such as nutrient availability, aerobic-to-anaerobic transitions, and pH changes. Investigation of ammonium transporters is important, as they play crucial roles in the uptake of nutrients by S. mutans in biofilm. The present study focused on characterizing the SMu1510 gene corresponding to nrgA in S. mutans, which is homologous to the ammonium transporter gene in Bacillus subtilis. The growth rate of an nrgA-deficient mutant strain (NRGD) was lower than that of the parental strain in the presence of ammonium. In addition, confocal laser scanning microscopy revealed that the structure of biofilm formed by NRGD was drastically different as compared to formed by the parental strain. These results suggest that the nrgA gene in S. mutans is essential for export of molecules and biofilm formation.

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  • Study on canine periodontal disease as zoonosis

    Grant number:23658256  2011 - 2013

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    ASAI Fumitoshi, KATO Yukio, NAKANO Kazuhiko, NAKANO Michiyo

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    Grant amount:\3770000 ( Direct expense: \2900000 、 Indirect expense:\870000 )

    The objective of the present study was to determine whether dog periodontal diseases are zoonotic and clarified the relationship between periodontal and systemic diseases. Oral swab samples were collected from dogs kept as family pets. Polymerase chain reaction was used to detect the presence of periodontopathic bacterial strains—10 from humans and 1 from dogs. P. gulae was detected in nearly all of the 100 or more dogs that were analyzed. By analyzing a fimbrial gene (fimA) sequence, we identified 3 types of P. gulae: type-A, type-B, and type-C. Type-C was the most virulent. A correlation between P. gulae type-C and cardiovascular disease was found by investigating the association between periodontal and systemic diseases.

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  • Analysis of biological function of recombinase A in Streptococcus mutansquorum sensing

    Grant number:22592283  2010 - 2012

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    INAGAKI Satoko, OOSHIMA Takashi, NAKANO Michiyo

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    Grant amount:\4550000 ( Direct expense: \3500000 、 Indirect expense:\1050000 )

    Streptococcus mutansproduces 3 types of glucosyltransferases (GTFs), whose cooperative action is essential for cellular adhesion, with the recombinase A (RecA) protein required for homologous recombination. Determination of the sequences of the gtfBand gtfCgenes showed that an approximately 3500-bp region was deleted in the smooth colonies of S. mutans. These results suggest that DNA recombination and phenotypic changes that occur through uptake of extracellular RecA may have a relationship with the signal transduction system involving biofilm formation in S. mutans.

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  • Analysis of mutans streptococci signal transduction system in biofilm formation

    Grant number:20592399  2008 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    NAKANO Michiyo

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )

    Quorum sensing has been reported to mediate biofilm formation by Streptococcus mutans. Recombinase A (RecA) encoded by the recA gene, is essential for transformation of both plasmids and chromosomal DNA. We found that the expression intensity of glucosyltransferases was reduced and biofilm structure altered in an RecA-deficient mutant strain. Thus, RecA was shown to have strong relationships with biofilm formation and quorum sensing.

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  • Molecular analysis of gloom-binding Protein in canes Pathogenesis of S. mutans

    Grant number:18592233  2006 - 2007

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    NAKANO Michiyo

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    Grant amount:\3830000 ( Direct expense: \3500000 、 Indirect expense:\330000 )

    Streptococcus mutans has been implicated as a major causative agent of dental caries in humans. Bactreial components associated with the adhesion phase of S. mutans include glucosyltransferase, protein antigen c, and proteins that bind glucan. At least four glucan-binding proteins (Gbp) have been identified; GbpA, GbpB, GbpC, and GbpD. In our previous study,the contributions of GbpA and GbpC to the virulence of S. mutans were investigated; however, the biological function of GbpB and its role in the virulence of S. mutans remain to be elucidated. Using a GbpB-deficient mutant strain (BD1), we demonstrated in the present study that GbpB has a role in the biology of S. mutans. The growth rate of BD1 was lower than that of other strains, while it was also shown to be less susceptible to phagocytosis and to form longer chains than the parental strain MT8148. In addition, electron microscope observations of the cell surfaces of BD1 showed that call-wall layers were obscure. These results suggest that GbpB may have an important role in the cell-wall construction and be involved in cell separation and cell maintenance.

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  • 植物ポリフェノールのう蝕抑制効果に関する分子生物学的解明

    Grant number:15791205  2003 - 2004

    日本学術振興会  科学研究費助成事業 若手研究(B)  若手研究(B)

    仲野 道代

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    Grant amount:\3600000 ( Direct expense: \3600000 )

    現在,様々な植物中に含まれているポリフェノールがう蝕の発生を抑制することがいわれている。また,う蝕病原細菌Streptococcus mutans表層には様々なタンパクが存在している。我々はこのうちグルカン合成酵素(Glucosylltransferase:GTF)の機能ドメインにどのように作用することにより,ポリフェノールがう蝕抑制効果を発揮するか調べた。ウーロン茶ポリフェノールはGTFのブルカン結合領域に結合し,グルコースの転移を阻害することにより,う蝕抑制効果を発揮することが明らかとなった。

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  • 教えてヨミドック Newspaper, magazine

    読売東京  読売新聞  2010.10.16

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    Author:Myself