PAI-2/SerpinB2 inhibits proteolytic activity in a P. gingivalis-dominated multispecies bacterial consortium

ObjectiveThe aim of this study was to investigate the ability of the serine protease inhibitor plasminogen activator inhibitor type 2 (PAI-2/Serpin B2) to inhibit proteases produced by a multispecies bacterial consortium in vitro.BackgroundGingival and periodontal inflammation is associated with an increased flow of protein-rich gingival fluid. This nutritional change in the microenvironment favors bacteria with a proteolytic phenotype, triggering inflammation and associated tissue breakdown. PAI-2 is produced by macrophages and keratinocytes and is present in very high concentrations in gingival crevicular fluid; the highest level in the body.DesignA multispecies bacterial consortium comprising nine bacterial strains, resembling the conditions in a periodontal pocket, was grown planktonically and as a biofilm. After seven days PAI-2 was added to the consortium and the proteolytic activity was assayed with fluorogenic protease substrates; FITC-labeled casein to detect global protease activity, fluorescent H-Gly-Pro-AMC for serine protease activity and fluorescent BIKKAM-10 for Porphyromonas gingivalis-associated protease activity. Protease activity associated with biofilm cells was examined by confocal scanning laser microscopy.ResultsPAI-2 inhibited proteolytic activity of the bacterial consortium, as seen by decreased fluorescence of all substrates. PAI-2 specifically inhibited P. gingivalis proteolytic activity.ConclusionTo our knowledge, this is the first time that PAI-2 has been shown to inhibit bacterial proteases. Given the high concentration of PAI-2 in the gingival region, our results indicate that PAI-2 might play a role for the integrity of the epithelial barrier.     

Selective modulation of bacterial attachment to oral epithelial cells by enzyme activities associated with poor oral hygiene

The present investigation explored the hypothesis that elevated levels of certain enzymes in the gingival crevicular environment of individuals with poor oral hygiene and/or gingival inflammation may modify the surfaces of epithelial cells and thereby modulate the types of bacteria which attach and colonize. Buccal epithelial cells treated with neuraminidase and certain proteases were used as a model for study. Bacteria studied included Streptococcus sanguis and Streptococcus mitis which have been associated with gingival health, Actinomyces species which are increased in plaque associated with developing gingivitis, and Bacteroides gingivalis, Bacteroides intermedius, and Actinobacillus actinomycetemcomitans which are associated with destructive periodontal diseases. Treatment of epithelial cells with the enzymes studied produced selective effects on their receptivity for bacteria. Neuraminidase treatment of epithelial cells greatly reduced the attachment of all strains of S. sanguis and S. mitis studied. In contrast, the number of Actinomyces viscosus, A. naeslundii and A. israelii cells which attached was significantly increased. Neuraminidase treatment also appeared to enhance attachment of B. intermedius and B. gingivalis. Treatment of buccal cells with trypsin, chymotrypsin or papain also selectively affected bacterial attachment. Such protease treatment greatly reduced the numbers of streptococci and A. viscosus cells which attached, while the numbers of B. gingivalis and B. intermedius were significantly increased. Treatment of epithelial cells with preparations of lysosomal enzymes derived from human PMNs produced similar selective effects. The changes in bacterial adhesion observed by the enzyme treatments studied are consistent with the shifts in the composition of the gingival crevice flora which occur when oral hygiene is terminated and gingivitis develops.     

Biofilm growth of Lactobacillus species is promoted by Actinomyces species and Streptococcus mutans

The ability of oral bacteria to integrate within a biofilm is pivotal to their survival. A dependence on the amount of biofilm growth by noncoaggregating Lactobacillus rhamnosus and Lactobacillus plantarum on coculture with Actinomyces naeslundii, Actinomyces gerencseriae, Streptococcus mutans and Veillonella parvula was investigated using an artificial-mouth culture system. Biofilm formation by the lactobacilli in mono-culture was poor. In coculture with Actinomyces species the amount of L. rhamnosus increased 7-20 times and L. plantarum 4-7 times compared to its mono-culture biofilm. S. mutans also promoted substantial biofilm growth of lactobacilli but V. parvula had no effect. We conclude that these Actinomyces species promoted growth of key Lactobacillus species in a biofilm, as did S. mutans to a smaller extent, and that the ability of individual bacteria to form mono-culture biofilms is not necessarily an indicator of their survival and pathogenic potential in a complex multispecies biofilm community.     

Proteases of an early colonizer can hinder Streptococcus mutans colonization in vitro

Streptococcus mutans is the primary cariogen that produces several virulence factors that are modulated by a competence-stimulating peptide (CSP) signaling system. In this study, we sought to determine if proteases produced by early dental plaque colonizers such as Streptococcus gordonii interfere with the subsequent colonization of S. mutans BM71 on the existing streptococcal biofilms. We demonstrated that S. mutans BM71 colonized much less efficiently in vitro on streptococcal biofilms than on Actinomyces naeslundii biofilms. Several oral streptococci, relative to A. naeslundii, produced proteases that inactivated the S. mutans CSP. We further demonstrated that cell protein extracts from S. gordonii, but not from A. naeslundii, interfered with S. mutans BM71 colonization. In addition, S. mutans BM71 colonized more efficiently on the sgc protease knockout mutant of S. gordonii than on the parent biofilms. In conclusion, proteases of early colonizers can interfere with subsequent colonization by S. mutans in vitro.     

Relationship Between Halitosis and Periodontitis: a Pilot Study

ObjectiveHalitosis, or oral malodour, is an unpleasant smell emanating from the oral cavity. It is a common complaint among patients with periodontitis, however, their relationship is not fully elucidated. This study aimed to evaluate the association between halitosis measures, clinical indicators of periodontitis and tongue coating, as well as a novel measure, periodontal inflamed surface area (PISA).Material and methodsData of 10 patients with periodontitis and halitosis were included in this study. Halitosis was assessed by the organoleptic method and the portable sulphide monitor, measuring volatiles sulphur compounds. A comprehensive periodontal examination was conducted, and the parameters of probing depth, gingival recession, clinical attachment level, bleeding on probing, plaque and tongue coating were registered. The PISA was calculated using clinical attachment level, gingival recession and bleeding on probing.ResultsA correlation between organoleptic score and tongue coating (r=0.554) and plaque (r=0.614) could be observed. No correlation between measures of halitosis and probing depth or the PISA could be detected. A significant correlation was found between organoleptic scores and volatiles sulphur compounds values (r=0.931).ConclusionThis pilot study has shown and further reiterated a complex interplay between different factors causative to halitosis in patients affected by periodontitis. The results suggest that tongue coating and oral hygiene may have an important role in halitosis in patients with periodontitis.     

Saliva viscosity as a potential risk factor for oral malodor

Objectives. The objective of this study was to assess whether saliva viscosity, measured by a viscometer, was a predictor of oral malodor. Materials and methods. The subjects were 617 patients who visited an oral malodor clinic. The organoleptic test (OT) was used for diagnosis of oral malodor. An oral examination assessed the numbers of teeth present and decayed teeth as well as the presence or absence of dentures. Further, periodontal pocket depths (PD), gingival bleeding, dental plaque and tongue coating were investigated. Unstimulated saliva were collected for 5 min. Saliva viscosity was measured with a viscometer. Logistic regression analysis with oral malodor status by OT as a dependent variable was performed. Possible confounders including age, gender, number of teeth present, number of decayed teeth, number of teeth with PD ≥ 4 mm, number of teeth with bleeding on probing, presence or absence of dentures, plaque index, area of tongue coating, saliva flow rate, saliva pH and saliva viscosity were used as independent variables. Results. Saliva viscosity (p = 0.047) along with the number of teeth with PD ≥4 mm (p = 0.001), plaque index (p = 0.037) and area of tongue coating (p < 0.001) were significant variables for oral malodor. Subjects with a higher number of teeth with PD ≥ 4 mm (OR = 1.32), plaque index (OR = 2.13), area of tongue coating (OR = 3.17) and saliva viscosity (OR = 1.10) were more likely to have oral malodor compared to those with lower values. Conclusions. The results suggested that high saliva viscosity could be a potential risk factor for oral malodor.     

Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm

Introduction

Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation.

Succession of oral bacterial colonizers on dental implant materials: An in vitro biofilm model

ObjectivesOral bacterial adhesion on dental implant materials has been extensively studied using in vitro systems but has yielded results restricted to in vitro growth patterns due to limitations in species selection, sustained fastidious anaerobe growth, and mixed culture longevity. The aim of this study was to develop an oral bacterial biofilm model consisting of colonizers representative of the oral microbiome exhibiting temporal shifts characteristic of plaque development and maturation in vivo.MethodsStreptococcus oralis, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Veillonella parvula, Fusobacterium nucleatum, and Porphyromonas gingivalis were grown in monoculture prior to combination in mixed culture. Commercially pure titanium (cpTi) and yttria-stabilized zirconia (ZrO₂) disks with polished, acid-etched, or sandblasted surfaces were prepared to evaluate oral bacterial adhesion. After 6 h, 1, 3, 7, 14 and 21 days, genomic DNA from planktonic and adherent bacteria was isolated. Quantitative polymerase chain reaction (qPCR) was used to enumerate the amount and proportion of each species.ResultsEarly-colonizing S. oralis and A. actinomycetemcomitans, dominated after 6 h prior to secondary colonization by F. nucleatum and V. parvula in planktonic (1 day) and sessile (3 days) form. A. naeslundii maintained relatively low but stable bacterial counts throughout testing. After 14 days, late-colonizing P. gingivalis became established in mixed culture and persisted, becoming the dominant species after 21 days. The composition of adherent bacteria across all substrates was statistically similar at all timepoints with notable exceptions including lower S. oralis bacterial counts on polished cpTi (3 days).SignificanceWithin the present model’s limitations, multispecies oral bacterial attachment is similar on surface-treated cpTi and ZrO₂.     

Tetracycline and its derivatives strongly bind to and are released from the tooth surface in active form

Several antibiotics were found to adsorb to saliva-coated enamel and to inhibit in vitro plaque formation by pure cultures of oral bacteria: Actinomyces viscosus, Actinomyces naeslundii and Streptococcus mutans. Tetracycline, minocycline and oxytetracycline adsorbed to the greatest degree, showing 100-fold higher adsorption than spiramycin, the test antibiotics with least adsorption. Inhibition of in vitro plaque formation was found to require both drug substantivity (capacity for adsorption) and antimicrobial activity. Inhibition of plaque formation in the in vitro assay employed correlated well with clinical efficacy.     

Purification of large quantities of human salivary cystatins S, SA and SN: their interactions with the model cysteine protease papain in a non-inhibitory mode

OBJECTIVES: Our aim was to purify large quantities of human salivary cystatins S, SA and SN in order to determine whether these salivary cystatins have a stable interaction with cysteine proteases at a second binding site, other than the protease active site. This property may affect their availability to act as cysteine protease inhibitors within the oral environment. METHODS: Salivary cystatins S, SA and SN were purified from human submandibular sublingual saliva to homo- geneity by column chromatography. Formation of stable complexes between the model cysteine protease papain in the absence of reductant was assessed by SDS-PAGE and probing Western blots with antibody to human salivary cystatin SN. Proteolytic activity of the complex was determined in the gel after electrophoresis. RESULTS AND CONCLUSIONS: Only cystatin SN (14.3 kD) was found to form a stable complex with papain (22 kD) that could be separated by SDS-PAGE producing a Coomassie stained band at (37 kD). After western transfer this same band (37 kD) cross-reacted with antibody to SN. In the presence of E64, an active site inhibitor of cysteine proteases, the same complex was formed, suggesting that SN is able to bind to papain at a site other than the active site. Activity staining of the gel confirmed that this complex (-E64) retained proteolytic activity. Such complex formation between cystatin SN and cysteine proteases in a non-inhibitory mode may reduce its availability to act as an effective cysteine protease inhibitor in the oral environment.     

Effects of tongue and oral mucosa cleaning on oral Candida species and production of volatile sulfur compounds in the elderly in a nursing home

The purpose of this study was to investigate the effects of oral care using simple tools and methods on the cleanliness of the oral cavity in the elderly. Enrolled were 84 elderly subjects with a mean (+/-S.D) age of 85.1+/-7.0 years in a nursing home. They were given tongue and oral mucosa cleaning (the oral care) after lunch every day or every other day for two consecutive weeks by the authors. The effect of the oral care was studied in terms of Candida scores in tongue coating, concentration of volatile sulfur compounds (VSC) which are the main causative substance of bad breath, and change in tongue coating scores. The above parameters were measured five times; just before the oral care program, weekly during, and at the end of the oral care program. The groups of patients, who were given the oral care, especially the group of patients cared with sponge brushes every day, showed a significant reduction in Candida scores but not in VSC concentration and tongue coating scores. The present method of oral care proved effective in cleaning the tongue and oral mucosa, and the Candida scores appeared to be a reliable indicator for evaluation. It is suggested that this way of oral care is simple, easy and useful not only for the elderly at a nursing home but for the house-bound elder people who will rapidly increase in the near future in Japan.     

Effects of S-PRG eluate on oral biofilm and oral malodor

ObjectivesThis study evaluated the effects of a surface pre-reacted glass-ionomer (S-PRG) eluate on oral microbiota and dental biofilms in vitro, and on oral malodor and tongue bacterial loads clinically.Study designThe effect of S-PRG eluate on the growth and survival of salivary bacteria was examined under both aerobic and anaerobic conditions; its ability to inhibit new biofilm formation and disrupt mature biofilms was also evaluated. The concentration of volatile sulfur compounds (VSCs) was measured using a portable sulfide monitor before and after rinsing with S-PRG eluate or distilled water. The number of bacteria on the tongue surface was calculated using a portable bacterial counter before and after tongue scraping with S-PRG eluate or distilled water.ResultsNo zone of inhibition was seen for S-PRG eluate against salivary microbiota under either aerobic or anaerobic conditions; however, treatment with ≥20% S-PRG eluate was sufficient to suppress biofilm formation relative to untreated controls. Mature biofilms were significantly disrupted following treatment with ≥60% S-PRG eluate relative to controls. Rinsing with S-PRG eluate significantly reduced the level of VSCs relative to baseline; this effect was not seen with distilled water alone. Waste fluids collected after oral rinsing with S-PRG eluate contained more bacteria than rinsing with distilled water alone. Finally, tongue scraping using S-PRG eluate was shown to significantly reduce the number of bacteria on the tongue surface.ConclusionsS-PRG eluate inhibits biofilm formation and disrupts mature biofilms, although its antibacterial activity is limited. Oral rinsing and tongue cleaning with S-PRG eluate may reduce oral malodor by effectively removing oral bacteria from the oral cavity.     

牙菌斑生物膜研究模型的进展

口腔微生物群落是典型的生物膜,牙菌斑生物膜是多种菌属组成的三维结构,黏附在牙齿表面,具有生物膜结构和微生物生理学的功能。牙菌斑生物膜是龋病和牙周病的主要致病因素,已有多种生物膜模型用于研究龋病的病因、预防和治疗的研究。这些龋病生物膜模型有助于研究者用一种可控、简化的方式来预测龋病的临床进展结果。目前,研究龋病微生物的模型有体外单菌种生物膜模型和多菌种生物膜模型。本文将从研究龋病的生物膜体外模型建立做一综述。     

Relationship between tongue coating and secretory-immunoglobulin A level in saliva obtained from patients complaining of oral malodor

AIM: The aim of this study was to confirm the relationships between oral malodor and periodontal condition, oral malodor and tongue coating, and to investigate the secretory-immunoglobulin A (S-IgA) level in saliva in relation to the accumulation of tongue coating. METHODS: Fifty-four patients complaining of oral malodor were included in the study. Their periodontal conditions, tongue coating status and salivary characteristics (flow rate, protein and S-IgA concentrations) were assessed in addition to the level of volatile sulfur compounds (VSC) in oral cavity. The patients were divided into three groups according to their tongue coating level. RESULTS: There are significant relationships between oral malodor and specific periodontal parameters used. The degree of tongue coating was also significantly correlated with the amount of H2S, CH3SH and the total amount of VSC determined. The concentration of S-IgA in the group identified as slight tongue coating was significantly higher than in the moderate or the severe group. By Western immunoblotting analysis, a high level of S-IgA specific to Streptococcus species was recognized in all groups, whereas the reactivity of Porphyromonas gingivalis and Fusobacterium nucleatum with S-IgA was very weak in both the slight and the moderate groups. CONCLUSION: Data herein indicate that tongue coating is closely related to oral malodor. Furthermore, S-IgA in saliva may influence the accumulation of tongue coating, and S-IgA antibodies directed to Streptococcus species may play a role in protective immunity against the initial colonization of tongue plaque.     

Relationship between sulcular sulfide level and oral malodor in subjects with periodontal disease

BACKGROUND: The relationship between oral malodor and sulfide levels in periodontal pockets (pS) has not yet been determined. The aims of this study were: 1) to identify the correlation among oral malodor, pS levels, and the BANA (benzoyl-DL-arginine-naphthylamide) test and 2) to recognize the interaction between oral malodor, demographic factors, tongue coating, and periodontal condition. METHODS: Eighty-one periodontal patients participated in this study. A portable sulfide monitor and organoleptic method were used to evaluate oral malodor. Demographic data included age, gender, race, and smoking habits. The volume of tongue coating and periodontal condition for all teeth were assessed. The pS levels of 3 different radiographic bone loss (RBL) sites: RBL < 2 mm, healthy; RBL > or = 2 to < 4 mm; low to moderate; RBL > or = 4 mm, severe, were measured using an industrial sulcular sulfide-monitoring device. Subgingival plaque samples from the above 3 sites and tongue scraping were examined by the BANA test. RESULTS: The volume of tongue coating (P<0.001), extent of periodontal disease (P<0.05), pS levels of the sites with low to moderate bone loss (P<0.05), and BANA score of tongue scrapings (P<0.05) were significantly associated with oral malodor. Stepwise multiple regression analysis examined the degree of association between oral malodor and potential explanatory variables. The volume of tongue coating and percent of sites BOP (bleeding on probing) were significantly associated with oral malodor. Females and smoking habit were negatively correlated with organoleptic measurements. CONCLUSIONS: The pS level of the representative sites with low to moderate bone loss demonstrated a modest association with oral malodor. Oral malodor in periodontal patients was primarily associated with tongue coating and gingival inflammation.     

Salivary β-galactosidase activity affects physiological oral malodour

ObjectivesPrevious reports have associated salivary β-galactosidase activity with non-periodontopathic oral malodour. In this study, we investigated the localization of β-galactosidase and elucidated the relationship between its enzymatic activity and physiological oral malodour.Study designFifty-six patients complaining of halitosis were separated into two groups: periodontally healthy and periodontitis. Saliva samples from the subjects were separated by centrifugation, and the level of β-galactosidase activity was measured in the supernatant, pellet lysate, and whole saliva using the chromogenic substrate o-nitrophenyl-β-d-galactopyranoside. The correlation of salivary β-galactosidase activity with breath odour and associated parameters was examined.ResultsSimilar levels of β-galactosidase activity were detected in the pellet lysate and whole saliva, but not in the saliva supernatant. Positive correlations were observed between the β-galactosidase activity in whole saliva and oral malodour levels in the periodontally healthy group, but not in the periodontitis group. In addition, the plaque index and tongue coating score were positively correlated with β-galactosidase activity in the periodontally healthy group. Overall, stimulated salivary flow and salivary pH were negatively correlated with enzyme activity. The amounts of total bacteria, Fusobacterium nucleatum, and Streptococcus salivarius were positively associated with β-galactosidase activity in the periodontally healthy group. Furthermore, the amounts of total bacteria and S. salivarius were positively associated with the amount of volatile sulphur compounds.ConclusionsOur results indicate that β-galactosidase is located on the cell surface of oral bacteria derived from dental plaque and tongue coating, and it plays an important role in producing the malodour underlying physiological oral malodour.     

口臭与牙周炎及舌苔的相关性研究

目的　探讨口臭及口气中挥发性硫化物 (volatilesulphurcompounds ,VSCs)与牙周炎及舌苔的相关性 ,舌在口臭及VSCs产生中的作用。方法　选择 6 0例全身健康、有口臭的牙周炎患者 ,鼻闻法检查口臭程度 ,使用便携式口臭测量仪分别测量清除舌苔前后的VSCs量。记录牙周袋探诊深度(probingdepth ,PD)及PD≥ 4mm位点比例 ,出血指数 (bleedingindex ,BI) ,菌斑指数 (plaqueindex ,PLI)及舌苔厚度与面积。结果　Spearman相关分析法显示 ,口臭值、VSCs量与BI、PLI、舌苔厚度存在明显的正相关性 (P <0 0 1) ,与舌苔面积也有关系 (P <0 0 5 )。口臭值与PD及PD≥ 4mm位点比例无关 ,VSCs量与PD及PD≥ 4mm位点比例存在一定的相关性 (r=0 2 6 ,P <0 0 5 )。清除舌苔可以明显降低VSCs量 (t=10 15 ,P <0 0 1) ,其减少量与舌苔厚度及面积均有明显相关性 (P <0 0 1)。结论　口臭值、VSCs量与BI、PLI及舌苔均有关系 ,而牙周袋PD只与VSCs量有关系 ;虽然清除舌苔可以明显降低VSCs量 (降低 36 7% ) ,但由于存在如何完全彻底清除舌苔的问题 ,所以舌与牙周炎在口臭及VSCs形成中的作用尚需进一步研究。     

A combined therapeutic approach to manage oral halitosis: a 3-month prospective case series

BACKGROUND: Clinical research assessing different therapeutic protocols aimed at treating oral halitosis is scarce. The aim of this study was to evaluate the effects of a combined mechanical and pharmacological approach to treat oral halitosis on clinical and microbiological outcomes on patients followed for 3 months. METHODS: Nineteen subjects with oral malodor participated. At baseline, all subjects completed a questionnaire and carried out an examination including full-mouth organoleptic and volatile sulfur compound (VSC) levels and the Winkel tongue coating index. Standard periodontal outcome variables were assessed at six teeth. Standardized microbiological samples of subgingival plaque, unstimulated saliva, and tongue coating were obtained for culture analysis. The treatment protocol included supragingival prophylaxis; instructions in oral hygiene (toothbrushing, interproximal cleaning, and tongue scraping); and gargling with a mouthrinse containing chlorhexidine, cetylpiridinium chloride, and zinc lactate. The same outcome variables were registered 1 and 3 months after baseline. RESULTS: Statistically significant reductions in organoleptic scores (P <0.001), VSC levels (P <0.05), and tongue coating index (P <0.05) were observed after 1 and 3 months. Mean probing depth and plaque levels also demonstrated significant reductions after 3 months (P <0.05). Total anaerobic counts were significantly reduced at all three locations after 1 month (P <0.05), and in samples from tongue coating and subgingival plaque at 3 months (P <0.05). Aerobic counts were significantly reduced in saliva at 1 month (P <0.05), and the anaerobic/aerobic ratio significantly increased in the tongue samples. Among the selected pathogens evaluated, Porphyromonas gingivalis was the most affected of the three microflora evaluated. CONCLUSIONS: The evaluated therapeutic approach demonstrated its efficacy in the management of oral halitosis, demonstrating statistically significant improvements in both organoleptic and VSC values at 1 and 3 months. The proposed clinical protocol significantly affected the microbial composition in tongue coating, saliva, and subgingival microflora.     

The effects of histatin-derived basic antimicrobial peptides on oral biofilms.

Susceptibility of bacteria to antimicrobial agents is strongly reduced by the formation of complex biofilms. We investigated whether synthetic histatin analogs with broad-spectrum antibacterial activity in vitro were also active against these complex mixtures of bacteria, as present in saliva and plaque. In a simplified model system for dental plaque, hydroxyapatite discs were placed in a continuous culture system comprised of Streptococcus mutans, S. sanguis, S. salivarius, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, and Prevotella intermedia. Ex situ treatment of the biofilms formed on these discs with 100 microg/mL of peptide dhvar4 significantly reduced facultative anaerobic, total anaerobic, and obligate anaerobic Gram-negative counts with 0.8, 0.5, and 0.5 log units, respectively. Ex vivo treatment of salivary bacteria gave reductions of 0.4, 0.7, and 1.5 log units, respectively. For ex vivo treatment of plaque bacteria, reductions of 0.4, 0.4, and 1.4 log units, respectively, were found. In both saliva and plaque samples, obligate anaerobic Gram-negative bacteria were significantly more susceptible to dhvar4 than facultatively anaerobic or anaerobic bacteria as a whole (p=0.013 and p=0.018, for salivary bacteria, and p=0.021 and p=0.020 for plaque bacteria, respectively). Although the oral bacteria are protected by biofilm formation, the synthetic histatin analog caused a significant reduction of viable counts in a model for oral biofilm as well as in isolated oral biofilms.     

Protein breakdown in submandibular glands rendered hypertrophic by amputation of lower incisor teeth in rats

Protein breakdown in submandibular glands rendered hypertrophic by amputation of the lower incisor teeth in rats was investigated. Reduced protein breakdown was observed in the hypertrophic gland tissues, and was found to be inhibited by 20 mM epsilon-amino-n-caproic acid, an inhibitor of serine protease, and 50 microM leupeptin, an inhibitor of trypsin, plasmin, papain and cathepsin B, but not by 2 mM PMSF (phenylmethylsulfonyl fluoride), an inhibitor of serine protease, 10 microM pepstatin, an inhibitor of cathepsin D and 20 microM antipain, an inhibitor of cathepsin A and B. These results suggest that some serine proteases and leupeptin-sensitive proteases (presumably cathepsin B) participate in protein breakdown in hypertrophic gland tissues, and that hypertrophy of the submandibular glands is closely related to the reduced protein breakdown in these tissues.