Biomedical subjects

T Ansai

Publications and source records attributed to T Ansai.

32 records · Page 2Linked to original sources

PubMed1999

Sequencing, expression and biochemical characterization of the Porphyromonas gingivalis pepO gene encoding a protein homologous to human endothelin-converting enzyme.

We have determined the nucleotide sequence of the clone pAL2 obtained from Porphyromonas gingivalis 381 in the previous study [Ansai et al. (1995) Microbiology 141, 2047-20521. The DNA sequence analysis of this fragment revealed one complete ORF and one incomplete ORF. The ORF encoded a protein (PgPepO) of 690 amino acids with a calculated molecular weight of 78796. The deduced amino acid sequence exhibited a significant homology with human endothelin-converting enzyme (ECE)-1. Recombinant PgPepO was purified to homogeneity and characterized. The purified enzyme was strongly inhibited by phosphoramidon, and converted big endothelin-1 to endothelin-1. Furthermore, the purified PgPepO strongly cross-reacted with a monoclonal antibody against rat ECE-1. These results indicate that PgPepO has striking similarity to mammalian ECE in structure and function.

Amino Acid Sequence↗

PubMed1999

Isolation, cloning, and expression of an acid phosphatase containing phosphotyrosyl phosphatase activity from Prevotella intermedia.

A novel acid phosphatase containing phosphotyrosyl phosphatase (PTPase) activity, designated PiACP, from Prevotella intermedia ATCC 25611, an anaerobe implicated in progressive periodontal disease, has been purified and characterized. PiACP, a monomer with an apparent molecular mass of 30 kDa, did not require divalent metal cations for activity and was sensitive to orthovanadate but highly resistant to okadaic acid. The enzyme exhibited substantial activity against tyrosine phosphate-containing peptides derived from the epidermal growth factor receptor. On the basis of N-terminal and internal amino acid sequences of purified PiACP, the gene coding for PiACP was isolated and sequenced. The PiACP gene consisted of 792 bp and coded for a basic protein with an M(r) of 29,164. The deduced amino acid sequence exhibited striking similarity (25 to 64%) to those of members of class A bacterial acid phosphatases, including PhoC of Morganella morganii, and involved a conserved phosphatase sequence motif that is shared among several lipid phosphatases and the mammalian glucose-6-phosphatases. The highly conservative motif HCXAGXXR in the active domain of PTPase was not found in PiACP. Mutagenesis of recombinant PiACP showed that His-170 and His-209 were essential for activity. Thus, the class A bacterial acid phosphatases including PiACP may function as atypical PTPases, the biological functions of which remain to be determined.

Acid Phosphatase↗

PubMed1998

Purification and characterization of alkaline phosphatase containing phosphotyrosyl phosphatase activity from the bacterium Prevotella intermedia.

A novel alkaline phosphatase, designated PiALP, has been purified and characterized from Prevotella intermedia ATCC 25611, an anaerobe implicated in progressive periodontal disease. The enzyme was a homodimer of apparently identical subunits of Mr 54 kDa. Thiol-reducing agents completely inhibited the purified enzyme. The enzyme was highly stable even at 80 degrees C. It exhibited substantial activity against tyrosine-phosphate-containing Raytide. The phosphatase activity was sensitive to orthovanadate and Zn2+ but highly resistant to okadaic acid. The amino acid sequence of peptides derived from PiALP showed a high degree of identity (65%) with alkaline phosphatases from Zymomonas mobilis and Synechococcus. The present results imply that PiALP might represent a new family of alkaline phosphotyrosyl phosphatases which has not been described previously.

Alkaline Phosphatase↗

PubMed1998

A comparison of DAI scores and characteristics of occlusal traits in three ethnic groups of Asian origin.

The Dental Aesthetic Index (DAI) is an orthodontic index based on socially defined aesthetic standards. The primary aim of this study was to compare the prevalence of malocclusion using the DAI among three ethnic groups of Asian origin; Japanese, Chinese in Taiwan and Native Americans with white Americans. A secondary goal was to consider the possibility that genetic factors might be the cause of the characteristics of malocclusion in the ethnic groups of Asian origin. Malocclusion was evaluated in 1029 Japanese and 176 Chinese in Taiwan students utilising the DAI, and the findings were compared with those of Native Americans and white Americans. The DAI values of Japanese and Native Americans were significantly higher than those of Chinese in Taiwan and white Americans. The mean DAI values showed no common tendency among the three ethnic groups. The characteristics of malocclusion in each ethnic group were also evaluated by analysis of each of the 10 DAI component scores. The results revealed common characteristics of malocclusion in the three ethnic groups of Asian origin using white Americans as the standard. The findings in the present study suggest the possibility that genetic factors might have an influence on the characteristics of malocclusion.

Adolescent↗

PubMed1997

Extracts of Prevotella intermedia and Actinobacillus actinomycetemcomitans inhibit alkaline phosphatase activity in osteoblastic cells in vitro.

In order to study the effects of sonicated extracts from Prevotella intermedia, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and other oral-related bacteria, as well as Escherichia coli on bone formation, clone MC3T3-E1 cells, which have retained osteoblastic activity, were cultured with various bacterial extracts. The addition of the sonicated extracts from Prevotella intermedia and Actinobacillus actinomycetemcomitans decreased the alkaline phosphatase activity in a dose-dependent fashion over the concentration range of 1-1000 ng ml-1 compared with the control. By contrast, the sonicated extracts from other oral bacteria including Porphyromonas gingivalis, Capnocytophaga ochracea, Streptococcus milleri and Streptococcus sanguis, and Escherichia coli did not decrease the alkaline phosphatase activity even in the presence of 100 ng ml-1 protein. The addition of Prevotella intermedia and Actinobacillus actinomycetemcomitans extracts that had been treated with heat and trypsin to the cell cultures also inhibited alkaline phosphatase activity in the cells, suggesting that inhibitory factors are not proteinaceous. Polymyxin B did not change the alkaline phosphatase activity in the cells treated with the extracts from Prevotella intermedia and Actinobacillus actinomycetemcomitans, suggesting that the inhibitory activity of the extracts is not lipopolysaccharide. The inhibitory effect of both extracts was observed in the molecular mass over 290 kDa eluted from Sephadex G-200 column. The inhibitory substances of Prevotella intermedia were partially purified and showed broad band with estimated molecular weight of 170-190 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These results indicate that Prevotella intermedia and Actinobacillus actinomycetemcomitans may play an important role in inhibiting bone formation as well as in stimulating bone resorption.

3T3 Cells↗

PubMed1996

Interactions between a minimal protein serine/threonine phosphatase and its phosphopeptide substrate sequence.

The protein phosphatase encoded by coliphage lambda (PPlambda) was found to be the equivalent of the minimal catalytic core of serine/threonine protein phosphatases (PP) by biochemical and mutational criteria. Bacterially expressed truncated versions of PP1 and PP5 phosphatases, representing the catalytic cores homologous to PPlambda, exhibited potent phosphatase activity. Unlike full-length PP1, but like PPlambda, the recombinant cores could use casein, p-nitrophenyl phosphate, and a wide variety of peptides as substrates and were resistant to okadaic acid, microcystin-LR, and trypsin. Mutations of His173, Asp208, or Arg221 had little effect on the activity of the PP1 core protein, indicating its closer identity with PPlambda than with full-length PP1. Terminal deletions of a few amino acids of the cores destroyed their activity, supporting their minimal nature. Analysis of PPlambda mutants suggested an influence of the substrate on metal ion binding. The minimal length of a phosphopeptide substrate of PPlambda appeared to be a phosphorylated serine/threonine flanked by 1 or 2 amino acid residues on either side, the N-terminal ones being more effective.

Amino Acid Sequence↗

PubMed1995

A murC gene in Porphyromonas gingivalis 381.

The gene encoding a 51 kDa polypeptide of Porphyromonas gingivalis 381 was isolated by immunoblotting using an antiserum raised against P. gingivalis alkaline phosphatase. DNA sequence analysis of a 2.5 kb DNA fragment containing a gene encoding the 51 kDa protein revealed one complete and two incomplete ORFs. Database searches using the FASTA program revealed significant homology between the P. gingivalis 51 kDa protein and the MurC protein of Escherichia coli, which functions in peptidoglycan synthesis. The cloned 51 kDa protein encoded a functional product that complemented an E. coli murC mutant. Moreover, the ORF just upstream of murC coded for a protein that was 31% homologous with the E. coli MurG protein. The ORF just downstream of murC coded for a protein that was 17% homologous with the Streptococcus pneumoniae penicillin-binding protein 2B (PBP2B), which functions in peptidoglycan synthesis and is responsible for antibiotic resistance. These results suggest that P. gingivalis contains a homologue of the E. coli peptidoglycan synthesis gene murC and indicate the possibility of a cluster of genes responsible for cell division and cell growth, as in the E. coli mra region.

Alkaline Phosphatase↗

PubMed1995

Periodontal conditions in older age cohorts aged 65 years and older in Japan, measured by CPITN and loss of attachment.

Periodontal conditions were assessed by CPITN and loss of attachment in 601 elderly people randomly selected in Kitakyushu, Japan. The percentage of edentulous persons was 21 per cent, 38 per cent and 65 per cent in the 65-74 year, 75-84 year and 85 years and older groups, respectively. In dentate persons, over 60 per cent had pocket probing depths of 4mm or more; in the majority loss of attachment did not exceed 5mm. The mean numbers of sextants with pocket probing depths of 4-5mm (CPITN 3) and probing depths of 6mm and more (CPITN 4) were similar in each age group. The mean numbers of sextants with both pockets and loss of attachment showed no clear difference among groups. Only the mean number of excluded (no, or only one tooth) sextants increased with increasing age from 1.9 to 3.1. It could therefore be suggested that in the population examined the progress of periodontal destruction with increasing age might not be shown by an increase in pocket probing depth, loss of attachment or gingival recession, but only by an increase in tooth loss. The results for the remaining teeth show that a) severe loss of periodontal attachment (6mm or more) was not frequently encountered, b) recession (attachment loss without pocketing) was present at only very low levels, c) the main periodontal problem seemed to be pocketing, which could be treated. It is therefore tempting to suggest that some of the teeth already lost, could have been saved if proper self- and professional care had been applied.

Aged↗

PubMed1994

Relationship between dental caries experience of a group of Japanese kindergarten children and the results of two caries activity tests conducted on their saliva and dental plaque.

To establish a dental caries preventive programme in 4- and 5-year-old children, caries activity tests were used to assess salivary levels of mutans streptococci (using the Mucount test, Showa Yakuhin, Japan) and the acidogenic ability of dental plaque bacteria (using the Cariostat test, Sankin, Japan) in 260 kindergarten children. The relationships between the results of these two tests and the dental caries experience (dfs) of the children was evaluated. There was a significant positive correlation between the results of the Mucount and Cariostat tests in the total group of subjects. However, 91 subjects (35%) gave conflicting results with the two tests. These subjects were divided into two groups: one group (group B) included Mucount-negative and Cariostat-positive subjects, and the other group (group C) included Mucount-positive and Cariostat-negative subjects. Group B had a significantly higher mean dfs score than a group that was negative on both tests (group A). On the other hand, no significant difference in mean dfs score was observed between group C and group A. These findings suggested that mutans streptococci levels alone are an insufficient indicator for assessing dental caries activity of children at these ages and that the role of lactobacilli and other aciduric bacteria should be considered. It was concluded that assessment of caries activity using both Mucount and Cariostat tests is useful for a dental caries preventive programme for children of these ages.

Child, Preschool↗

PubMed1993

Prevalence of malocclusion in high school students in Japan according to the Dental Aesthetic Index.

The Dental Aesthetic Index (DAI) was used to evaluate malocclusion in Japanese high school students (n = 409, ages 15-18 yr). The purpose of this study was to obtain basic data concerning malocclusion in Japanese high school students. This study used a sample of students from randomly selected urban and rural high schools in Japan's Kyushu district. The DAI scores for urban and rural high school students, as well as the total DAI scores from these two areas were significantly higher than that of American high school students. These results showed that the number of students with an acceptable dental appearance among Japanese high school students is significantly lower than among American high school students. This indicates a higher need for orthodontic treatment among Japanese high school students.

Adolescent↗

PubMed1992

Mechanism of water-insoluble glucan synthesis in Streptococcus sobrinus.

Synthesis of water-insoluble glucan (IG) by 1,3-alpha-D-glucan synthase from Streptococcus sobrinus was examined using methylation analysis. The purified enzyme was incubated with sucrose and dextran T2000 (DT2000) for a given time and only IG was harvested by centrifugation. The remaining supernatant was incubated again, and IG was obtained. By repeating the above method using the residual supernatant, we obtained 5 varieties of IG precipitated in different periods. These IGs were methylated and examined using gas chromatograph mass spectrometry. The DT2000 water-insolubilized in the early reaction stage tended to have a highly ramified structure, with 1,3-alpha-D-glucan on a 1,6-alpha-D-glucan chain as the main chain. On the contrary, the DT2000 water-insolubilized in the late stage tended to have sparse side chains of 1,3-alpha-D-glucan which elongated with incubation. Specifically, the greater the number of side chains, the sooner the DT2000 was insolubilized. These results suggest that water-insolubilization of the water-soluble glucan not only depends on the increase of the ratio of 1,3-alpha-glucoside linkages to 1,6-alpha-glucoside linkages but also on the degree of branching of the 1,3,6-alpha-branched glucoside linkages.

Glucans↗

PubMed1991

The extension of alpha-D-1,3-branch linkages by 1,3-alpha-D-glucan synthase from Streptococcus sobrinus.

In the presence of an acceptor, 1,3-alpha-D-glucan synthase of Streptococcus sobrinus synthesizes water-insoluble glucans from sucrose. Under such conditions, 1,3-alpha-D-glucoside linkages were extended without any change in the glucose-residue number between the 1,3,6-branch points on the acceptor. From these results, the mechanisms of water-insoluble-glucan formation were proposed as follows: (i) the attachment of an acceptor to the glucan binding sites of 1,3-alpha-D-glucan synthase occurs during the initiation of the reaction, and concurrently determines the positions of the branched portions of 1,3,6 on the acceptor, and (ii) the 1,3-alpha-D-glucoside linkage extends from these positions.

Carbohydrate Conformation↗

PubMed1990

Learning efficiency of a toothbrush for mastering scrubbing method.

Toothbrushing with long horizontal strokes often causes traumatization of sound enamel and gingival tissues. Also, dental plaque on cervical and adjacent surfaces of teeth can hardly be removed because toothbrush tips cannot reach these regions adequately. A toothbrushing device which indicates overstroke was tested to determine the efficacy with which it makes subjects master brushing with short horizontal strokes following an initial period of instruction. The degree of learning measured in the testing group was superior to that of the control group immediately after the first instruction. Moreover after one week and 12 weeks, its efficacy persisted. The plaque elimination ratio, however, showed no significant difference between the testing group and the control.

Adult↗

PubMedDate not supplied

Influence of colonization with mutans streptococci on caries risk in Japanese preschool children: 24 month survival analysis.

PURPOSE: This study evaluates how various microbial- and salivary-related risk factors influenced the hazard for caries development in preschool children. METHODS: The study population consisted of 131 subjects (age: 0.5 to 6.0 yrs). Oral examination, including two bacterial tests and buffering capacity test, was conducted at six month intervals over 24 months. A survival analysis was used to describe caries hazard over a 24-month follow-up period. A Cox proportional hazards regression analysis was performed to test the influence of salivary mutans streptococci (MS), aciduric bacteria, buffering capacity and age on caries development. RESULTS: Of the total subjects, 60 children (46%) were found to be caries-free at baseline. Caries hazard correlated significantly with salivary MS levels at baseline (relative risk, 1.7; P = 0.003), but not with aciduric bacteria and buffering capacity. This analysis showed that all of children with high colonization of MS at baseline had dental caries 15 months later. CONCLUSION: The results suggest that salivary MS level at baseline influenced caries hazard in preschool children.

Buffers↗