Effect of proteolytic enzymes on the lysis and growth of oral bacteria

Towards Electrochemical Sensor Based on Molecularly Imprinted Polypyrrole for the Detection of Bacteria-Listeria monocytogenes

Detecting bacteria-Listeria monocytogenes-is an essential healthcare and food industry issue. The objective of the current study was to apply platinum (Pt) and screen-printed carbon (SPCE) electrodes modified by molecularly imprinted polymer (MIP) in the design of an electrochemical sensor for the detection of Listeria monocytogenes. A sequence of potential pulses was used to perform the electrochemical deposition of the non-imprinted polypyrrole (NIP-Ppy) layer and Listeria monocytogenes-imprinted polypyrrole (MIP-Ppy) layer over SPCE and Pt electrodes. The bacteria were removed by incubating Ppy-modified electrodes in different extraction solutions (sulphuric acid, acetic acid, L-lysine, and trypsin) to determine the most efficient solution for extraction and to obtain a more sensitive and repeatable design of the sensor. The performance of MIP-Ppy- and NIP-Ppy-modified electrodes was evaluated by pulsed amperometric detection (PAD). According to the results of this research, it can be assumed that the most effective MIP-Ppy/SPCE sensor can be designed by removing bacteria with the proteolytic enzyme trypsin. The LOD and LOQ of the MIP-Ppy/SPCE were 70 CFU/mL and 210 CFU/mL, respectively, with a linear range from 300 to 6700 CFU/mL.

Fusobacterium nucleatum Metabolically Integrates Commensals and Pathogens in Oral Biofilms

Fusobacterium nucleatum is a common constituent of the oral microbiota in both periodontal health and disease. Previously, we discovered ornithine cross-feeding between F. nucleatum and Streptococcus gordonii, where S. gordonii secretes ornithine via an arginine-ornithine antiporter (ArcD), which in turn supports the growth and biofilm development of F. nucleatum; however, broader metabolic aspects of F. nucleatum within polymicrobial communities and their impact on periodontal pathogenesis have not been addressed. Here, we show that when cocultured with S. gordonii, F. nucleatum increased amino acid availability to enhance the production of butyrate and putrescine, a polyamine produced by ornithine decarboxylation. Coculture with Veillonella parvula, another common inhabitant of the oral microbiota, also increased lysine availability, promoting cadaverine production by F. nucleatum. We confirmed that ArcD-dependent S. gordonii-excreted ornithine induces synergistic putrescine production, and mass spectrometry imaging revealed that this metabolic capability creates a putrescine-rich microenvironment on the surface of F. nucleatum biofilms. We further demonstrated that polyamines caused significant changes in the biofilm phenotype of a periodontal pathogen, Porphyromonas gingivalis, with putrescine accelerating the biofilm life cycle of maturation and dispersal. This phenomenon was also observed with putrescine derived from S. gordonii-F. nucleatum coculture. Lastly, analysis of plaque samples revealed cooccurrence of P. gingivalis with genetic modules for putrescine production by S. gordonii and F. nucleatum. Overall, our results highlight the ability of F. nucleatum to induce synergistic polyamine production within multispecies consortia and provide insight into how the trophic web in oral biofilm ecosystems can eventually shape disease-associated communities.

IMPORTANCE Periodontitis is caused by a pathogenic shift in subgingival biofilm ecosystems, which is accompanied by alterations in microbiome composition and function, including changes in the metabolic activity of the biofilm, which comprises multiple commensals and pathogens. While Fusobacterium nucleatum is a common constituent of the supra- and subgingival biofilms, its metabolic integration within polymicrobial communities and the impact on periodontal pathogenesis are poorly understood. Here, we report that amino acids supplied by other commensal bacteria induce polyamine production by F. nucleatum, creating polyamine-rich microenvironments. Polyamines reportedly have diverse functions in bacterial physiology and possible involvement in periodontal pathogenesis. We show that the F. nucleatum-integrated trophic network yielding putrescine from arginine through ornithine accelerates the biofilm life cycle of Porphyromonas gingivalis, a periodontal pathogen, from the planktonic state through biofilm formation to dispersal. This work provides insight into how cooperative metabolism within oral biofilms can tip the balance toward periodontitis.

Advancements in the Pharmaceutical Applications of Probiotics: Dosage Forms and Formulation Technology

Probiotics have demonstrated their high potential to treat and/or prevent various diseases including neurodegenerative disorders, cancers, cardiovascular diseases, and inflammatory diseases. Probiotics are also effective against multidrug-resistant pathogens and help maintain a balanced gut microbiota ecosystem. Accordingly, the global market of probiotics is growing rapidly, and research efforts to develop probiotics into therapeutic adjuvants are gaining momentum. However, because probiotics are living microorganisms, many biological and biopharmaceutical barriers limit their clinical application. Probiotics may lose their activity in the harsh gastric conditions of the stomach or in the presence of bile salts. Moreover, they easily lose their viability under thermal or oxidative stress during their preparation and storage. Therefore, stable formulations of probiotics are required to overcome the various physicochemical, biopharmaceutical, and biological barriers and to maximize their therapeutic effectiveness and clinical applicability. This review provides an overview of the pharmaceutical applications of probiotics and covers recent formulation approaches to optimize the delivery of probiotics with particular emphasis on various dosage forms and formulation technologies.

The Associations of Periodontopathic Bacteria and Oral Candida with Periodontal Inflamed Surface Area in Older Adults Receiving Supportive Periodontal Therapy

The periodontal inflamed surface area (PISA) has been proposed for assessment of the total periodontal inflammatory status in people with periodontitis. This study was performed to investigate the associations of periodontopathic bacteria and candida with PISA in older people. We enrolled 100 patients aged ≥ 60 years who visited Hiroshima University Hospital. PISA and periodontal epithelial surface area (PESA) were calculated in each patient. Oral rinse samples were collected for DNA extraction. Periodontopathic bacteria and candida were detected by polymerase chain reaction. The mean values of PISA and PESA were significantly greater in T.forsythia-positive patients than in T.forsythia-negative patients. T.forsythia/C. albicans double-positive patients exhibited significantly greater PISA values than did non-double-positive patients. Additionally, PISA values were significantly greater in T. forsythia//T. denticola/C. albicans triple-positive patients than in T. forsythia//T. denticola/C. albicans non-triple-positive patients (p = 0.02). Propensity score-matching was performed between periodontopathic bacteria-positive and -negative patients using propensity scores generated from clinical factors. Importantly, T.forsythia/T. denticola double-positive patients exhibited significantly greater PISA values than non-double-positive patients among 72 propensity score-matched patients. Our preliminary results highlight the importance of the presence of T.forsythia and T. denticola for periodontal inflammation severity in older Japanese people.

Bactericidal effect on skin mucosa of dietary guava (Psidium guajava L.) leaves in hybrid tilapia (Oreochromis niloticus × O. mossambicus)

ETHNOPHARMACOLOGICAL RELEVANCE

Due to the intensification practices in global aquaculture, fish are often confined in small volumes, which can results in outbreak diseases. In this context, the use of antibiotics is very usual. Thus, looking for natural substance able to reduce the use of the antibiotics is imperative. Among them, there is a great interest at present in the study of medicinal plants such as guava (Psidium guajava L.). These plants could help to develop a more sustainable aquaculture all over the world. The application of guava in traditional medicine dates for centuries and it is widely used in tropical countries for the treatment of diseases in human and animals.

AIM OF THE STUDY

The purpose of this work was to study the effects of the dietary administration of dried leaves of Psidium guajava on the skin mucosal immunity of hybrid tilapia (Oreochromis niloticus × O. mossambicus). Furthermore, the ability of this plant to inhibit the bacterial load in different tissues after an experimental infection with Vibrio harveyi was studied.

MATERIALS AND METHODS

P. guajava leaves collection and the experimentation was carried out in Dominican Republic. Fish were fed with a commercial diet supplemented with guava leaf at different concentrations (0%, 1.5% and 3%) for 21 days before being intraperitoneally injected with V. harveyi (1 × 10⁴ cells mL^-1). Thereafter, several immune activities were measured in fish skin mucus and after 48 h of injection, the skin, spleen and liver were collected to analyse the bactericidal activity of guava leaf and the gene expression of some immune related genes.

RESULTS

The administration of P. guajava leaves significantly modulated some immune-related enzymes (protease, antiprotease and peroxidase) in the skin mucus of hybrid tilapia. In addition, the bacterial load after V. harveyi infection in skin, spleen and liver significantly reduced in fish supplemented with guava leaves. Finally, the expression profile of hepcidin gene in skin and liver was modulated in fish feed with control diet after V. harveyi infection.

CONCLUSION

These results demonstrate that the dietary intake of guava leaves increases the skin mucosal barrier defences of hybrid tilapia and confers protection against V. harveyi colonization.

Matrix metalloprotease-1 inhibits and disrupts Enterococcus faecalis biofilms

Enterococcus faecalis is a major opportunistic pathogen that readily forms protective biofilms leading to chronic infections. Biofilms protect bacteria from detergent solutions, antimicrobial agents, environmental stress, and effectively make bacteria 10 to 1000-fold more resistant to antibiotic treatment. Extracellular proteins and polysaccharides are primary components of biofilms and play a key role in cell survival, microbial persistence, cellular interaction, and maturation of E. faecalis biofilms. Degradation of biofilm components by mammalian proteases is an effective antibiofilm strategy because proteases are known to degrade bacterial proteins leading to bacterial cell lysis and growth inhibition. Here, we show that human matrix metalloprotease-1 inhibits and disrupts E. faecalis biofilms. MMPs are cell-secreted zinc- and calcium-dependent proteases that degrade and regulate various structural components of the extracellular matrix. Human MMP1 is known to degrade type-1 collagen and can also cleave a wide range of substrates. We found that recombinant human MMP1 significantly inhibited and disrupted biofilms of vancomycin sensitive and vancomycin resistant E. faecalis strains. The mechanism of antibiofilm activity is speculated to be linked with bacterial growth inhibition and degradation of biofilm matrix proteins by MMP1. These findings suggest that human MMP1 can potentially be used as a potent antibiofilm agent against E. faecalis biofilms.

Lysine-specific proteolytic activity responsible for forsythia detaching factor modification

OBJECTIVES

The objective of the present study was to clarify the lysine-specific proteolytic activity derived from periodontal pathogens responsible for Forsythia detaching factor (FDF) modification.

DESIGN

The activity responsible for FDF modification in Tannerella forsythia and Porphyromonas gingivalis were evaluated by colorimetric assay using Ac-Arg-Ala-Lys-p-nitroaniline as a substrate. FDF modification in T. forsythia and P. gingivalis were evaluated by Western blotting using recombinant FDF (rFDF) as a substrate. Furthermore, the activity in GCF of 20 patients with periodontitis and 10 healthy subjects was also evaluated by colorimetric assay. Bacteria in subgingival plaque were detected using polymerase chain reaction.

RESULTS

The activity of both bacteria in colorimetric assay were 21.35 unit (P. gingivalis) and 3.61 unit (T. forsythia), respectively. Western blot analysis revealed that P. gingivalis was found to efficiently degrade rFDF and T. forsythia partially cleaved rFDF. The activity in GCF from patients with periodontitis (clinically healthy sites: CH, deep bleeding sites: DB and deep non-bleeding sites: DNB) was significantly higher than those from healthy subjects (healthy sites: H). Among the patients with periodontitis, the activity from CH was significantly lower than those from DB and DNB. T. forsythia was detected in 68.4% of DNB, in 78.4% of DB and in none of CH. P. gingivalis was detected in 63.2% of DNB, in 84.0% of DB and in 10.5% of CH. No bacterium was detected in healthy subjects.

CONCLUSION

The lysine-specific proteolytic activity responsible for FDF modification correlates with the presence of major periodontal pathogens.

Proteomics of Fusobacterium nucleatum within a model developing oral microbial community

Fusobacterium nucleatum is a common oral organism that can provide adhesive and metabolic support to developing periodontal bacterial communities. It is within the context of these communities that disease occurs. We have previously reported whole cell proteomics analyses of Porphyromonas gingivalis and Streptococcus gordonii in early-stage communities with each other and with F. nucleatum, modeled using 18 h pellets. Here, we report the adaptation of F. nucleatum to the same experimental conditions as measured by differential protein expression. About 1210 F. nucleatum proteins were detected in single species F. nucleatum control samples, 1192 in communities with P. gingivalis, 1224 with S. gordonii, and 1135 with all three species. Quantitative comparisons among the proteomes revealed important changes in all mixed samples with distinct responses to P. gingivalis or S. gordonii alone and in combination. The results were inspected manually and an ontology analysis conducted using DAVID (Database for annotation, visualization, and integrated discovery). Extensive changes were detected in energy metabolism. All multispecies comparisons showed reductions in amino acid fermentation and a shift toward butanoate as a metabolic byproduct, although the two organism model community with S. gordonii showed increases in alanine, threonine, methionine, and cysteine pathways, and in the three species samples there were increases in lysine and methionine. The communities with P. gingivalis or all three organisms showed reduced glycolysis proteins, but F. nucleatum paired with S. gordonii displayed increased glycolysis/gluconeogenesis proteins. The S. gordonii containing two organism model also showed increases in the ethanolamine pathway while the three species sample showed decreases relative to the F. nucleatum single organism control. All of the nascent model communities displayed reduced translation, lipopolysaccharide, and cell wall biosynthesis, DNA replication and DNA repair.

Modification of forsythia detaching factor by gingival crevicular fluid in periodontitis

OBJECTIVES

Forsythia detaching factor (FDF) is a virulence factor of Tannerella forsythia detected as a mixture of the 60-kDa form of FDF and the 28-kDa C-terminal fragment (FDFc). The objective of the present study was to clarify the proteolytic activity of gingival crevicular fluid (GCF) from patients with periodontitis and healthy subjects using recombinant FDF (rFDF) as substrate.

DESIGN

Eleven patients with periodontitis and 6 healthy subjects were recruited. Modification of rFDF and subsequent production of rFDFc by proteolytic activity of GCF was determined by Western blotting. Proteolytic activity of GCF was evaluated using an Ac-Arg-Ala-Lys-p-nitroaniline substrate. Correlation analysis between two different sets of variables was performed. Variables used in this analysis were proteolytic activity, clinical parameters, relative band density of rFDFc and those of rFDF.

RESULTS

Proteolytic activity in GCF was significantly higher in patients with periodontitis than in healthy subjects. Production of rFDFc was determined by treatment of rFDF with GCF from patients with periodontitis and with GCF from healthy subjects. Correlations between clinical parameters and proteolytic activity in GCF were significantly positive. On the other hand, correlations between relative band density of rFDFc or rFDF on Western blot and cleaving activity or clinical parameters were significantly negative.

CONCLUSION

The detected extend of GCF-activity generating rFDFc from rFDF and/or even further degrading rFDF correlates with severity of periodontitis.

Where do the immunostimulatory effects of oral proteolytic enzymes (‘systemic enzyme therapy’) come from? Microbial proteolysis as a possible starting point

Enteric-coated proteolytic enzyme preparations like Wobenzym and Phlogenzym are widely used for the so-called 'systemic enzyme therapy' both in humans and animals. Numerous publications reveal that oral proteolytic enzymes are able to stimulate directly the activity of immune competent cells as well as to increase efficiency of some of their products. But origins of the immunostimulatory effects of oral proteolytic enzymes are still unclear. The hypothesis described here suggests that it may be proteolysis of intestinal microorganisms that makes the immune competent cells to work in the immunostimulatory manner. The hypothesis was largely formed by several scientific observations: First, microbial lysis products (lipopolysaccharides, muropeptides and other peptidoglycan fragments, beta-glucans, etc.) are well known for their immunostimulatory action. Second, a normal human being hosts a mass of intestinal microorganisms equivalent to about 1 kg. The biomass (mainly due to naturally occurring autolysis) continuously supplies the host's organism with immunostimulatory microbial cell components. Third, the immunostimulatory effects resulting from the oral application of exogenously acting antimicrobial (lytic) enzyme preparations, such as lysozyme and lysosubtilin, are likely to be a result of the action of microbial lysis products. Fourth, cell walls of most microorganisms contain a considerable amount of proteins/peptides, a possible target for exogenous proteolytic enzymes. In fact, several authors have already shown that a number of proteases possess an ability to lyse the microbial cells in vitro. Fifth, the pretreatment of microbial cells (at least of some species) in vitro with proteolytic enzymes makes them more sensitive to the lytic action of lysozyme and, otherwise, pretreatment with lysozyme makes them more susceptible to proteolytic degradation. Sixth, exogenous proteases, when in the intestines, may participate in final steps of food-protein digestion. The resulting food-borne peptides have recently been shown to be potential activators of microbial autolysis. The main question that needs to be answered in order to verify the hypothesis is whether oral proteases are able (and to what extent) to lyse/mediate lysis of intestinal microorganisms in situ. Methods based on up-to-date molecular biology techniques to allow investigation of the influence of exogenous proteases on microbial lysis processes in vivo (in the intestines) need to be developed. Research testing of this hypothesis may have an important impact in development of novel preparations for the systemic enzyme therapy.

A simple approach to examine early oral microbial biofilm formation and the effects of treatments

BACKGROUND/AIMS

A simple in vivo approach to examine early dental plaque formation in the human mouth and to determine the effects of common dietary and oral hygiene procedures on biofilm formation is reported.

METHODS

A custom designed device that fits securely behind the teeth of the mandibular arch provides a surface for microbial colonization. This device is prepared with denture acrylic and can be repeatedly used by the subject, exposing a large and constant surface area for microbial accumulation.

RESULTS

Large numbers of oral bacteria colonized the device by 2 h; these increased significantly by 4 h (P < 0.05). Bacterial colonization increased significantly after rinsing with a sucrose solution (P < 0.05) but remained unaffected after rinsing with water, a commercially available fluoride mouthrinse without antimicrobial agents, or brushing with a fluoride dentifrice (P > 0.05). Rinsing with mouthrinses formulated with chlorhexidine, cetylpyridinium chloride or triclosan/copolymer significantly inhibited colonization (P < 0.05). A dose-dependent inhibition was noted with chlorhexidine rinses (P < 0.05). Brushing with a triclosan/copolymer dentifrice significantly inhibited microbial colonization compared with a control (P < 0.05).

CONCLUSION

This simple approach was useful for examining the effects of common dietary and oral hygiene procedures. Significant biofilm inhibitory effects were noted with formulations that demonstrated efficacy in previous clinical studies.

Fusobacterium nucleatum supports the growth of Porphyromonas gingivalis in oxygenated and carbon-dioxide-depleted environments

The authors compared the differences in tolerance to oxygen of the anaerobic periodontopathic bacteria Fusobacterium nucleatum and Porphyromonas gingivalis, and explored the possibility that F. nucleatum might be able to support the growth of P. gingivalis in aerated and CO2-depleted environments. Both micro-organisms were grown as monocultures and in co-culture in the presence and absence of CO2 and under different aerated conditions using a continuous culture system. At steady state, viable counts were performed and the activities of the enzymes superoxide dismutase and NADH oxidase/peroxidase were assayed in P. gingivalis. In co-culture, F. nucleatum was able to support the growth of P. gingivalis in aerated and CO2-depleted environments in which P. gingivalis, as a monoculture, was not able to survive. F. nucleatum not only appeared to have a much higher tolerance to oxygen than P. gingivalis, but a significant increase in its numbers occurred under moderately oxygenated conditions. F. nucleatum might have an additional indirect role in dental plaque maturation, contributing to the reducing conditions necessary for the survival of P. gingivalis and possibly other anaerobes less tolerant to oxygen. Additionally, F. nucleatum is able to generate a capnophilic environment essential for the growth of P. gingivalis.

Comparative studies on Polyferm and Fermosorb, two oral (ferment + sorbent) - type preparations designed for therapy/prophylaxis of intestinal infections in animal neonates

Polyferm and Fermosorb are oral acid resistant antimicrobial enzyme preparations designed specifically for therapy/prophylaxis of intestinal infections in animal neonates. Both are authorized for use throughout the former Soviet Union, but until now only Fermosorb is being applied on a large scale. The comparative studies on these two preparations, described in this paper, were carried out in order to find differences between the preparations. Characteristics that were compared included stability of the preparations in acidic environment as well as in storage (in vitro studies), and their efficacy for the treatment and prophylaxis of colibacillosis in newborn calves (in vivo studies). Results of in vitro studies revealed that proteolytic enzymes of Polyferm (as well as lytic enzymes of Fermosorb) were suitably (and in a very similar magnitude) protected from the influence of the acidic environment. The complete enzyme activity retention period in storage at room temperature of Polyferm and Fermosorb was equally high (5 years). In vivo studies performed on 2000 calves revealed that both preparations were highly effective and, although the efficacy of Polyferm was a bit lower than that of Fermosorb (93.6% vs. 95.0%, 94.6% vs. 95.8% for therapy and prophylaxis of colibacillosis, respectively), no statistically significant differences in the number of Polyferm vs. Fermosorb cured/protected animals were found. It is concluded that there were no reasons, other than the lack of supportive advertising materials, that might impede the utility of Polyferm.

Lysosubtilin modification, Fermosorb, designed for polymeric carrier-mediated intestinal delivery of lytic enzymes: pilot-scale preparation and evaluation of this veterinary medicinal product

Antimicrobial enzymotherapy/enzymoprophylaxis has potential for use as a measure to overcome problems associated with resistance to commonly applied antibiotics. Lysosubtilin, an authorized veterinary medicinal product, when used per os for the treatment and prophylaxis of intestinal infections in newborn calves, is not always efficient due to partial inactivation of lytic enzymes in the gastric region. In this contribution a simple technology for preparation of pH-dependent reversibly dissociating acid stable enzyme-polymer complex (two-component oral delayed-release lysosubtilin formulation, Fermosorb) designed for intestinal delivery of lytic enzymes is described. The technology is based on immobilization of lytic enzymes, using 1% lysosubtilin solution in 10 mM acetate buffer of pH 5.0, onto commercial highly porous carboxylic cation exchanger Biocarb L (v/w ratio 10:1, process duration 1 h) with after-following procedures of vacuum-filtration, oven-drying and standardization of the enzyme-polymer complex formed. The technology process of pilot-scale Fermosorb fabrication on the whole revealed itself as simply employed and highly repeatable, totalling in the final lytic enzyme activity yield of 40.2% (the average value obtained from the analysis of the 11 batches running) and approximately 4000 (3938) kg of Fermosorb (200 batches) produced. The proposed technological approach can be successfully applied for fabrication of other enzyme preparations as well and this was shown in the example of Polyferm, a preparation with both lytic and proteolytic enzyme activities. In vitro evaluation of Fermosorb revealed it was more stable when exposed to the acidic environment as well as in storage when compared with the native lysosubtilin. No negative change in the antimicrobial spectrum of action of Fermosorb versus lysosubtilin, influenced by immobilization of lytic enzymes onto Biocarb L, was observed. Moreover, all six lysosubtilin-resistant microbial strains tested have been found to be Fermosorb-susceptible. In vivo evaluation studies performed on 1200 newborn calves revealed 95.2% therapeutic as well as 95.0% prophylactic efficacy of Fermosorb in respect to colibacillosis versus 74.0 and 80.0% for lysosubtilin, respectively, the differences being statistically significant (P<0.01). As a consequence of these studies Fermosorb was authorized for use throughout the former Soviet Union. Data collected during postmarketing surveillance of Fermosorb, which was applied for more than 163,000 newborn calves, confirmed high efficacy (92.3 and 95.5% for treatment and prophylaxis, respectively) and safety of this veterinary medicinal product.

Chymotrypsin-like enzyme secretion is stimulated in cultured epithelial cells during proliferation and in response to Actinobacillus actinomycetemcomitans

A chymotrypsin-like enzyme was partially purified from culture medium of epithelial cells of human skin, human gingiva and porcine periodontal ligament by aprotinin-affinity chromatography. The enzyme levels from all three cell types were low in quiescent cultures but increased markedly when the cells were allowed to proliferate. The biphasic elution profile of the enzyme from the affinity column closely matched that of alpha-chymotrypsin and the protein comigrated with it on polyacrylamide gels at 27,000 ML. Synthetic substrate tests of purified fractions showed strong chymotrypsin-like but no trypsin-like or elastase-like activity. Inhibition of protease activity and pH optimum in the range of 7.5-8.0 were consistent with chymotrypsin-like enzymes. Secreted activity was found to be significantly increased by phorbol myristate acetate treatment in a time-course that differed from that of elastase-like activity. Keratinocyte growth factor and epidermal growth factor but not transforming growth factor-beta increased the chymotrypsin-like activity in a concentration-dependent manner. The enzyme secretion by epithelial cells was strongly elevated by exposure to 5 of 6 Actinobacillus actinomycetemcomitans strains isolated from plaque samples of juvenile periodontitis patients. These results indicate that chymotrypsin-like enzymes are secreted by proliferative phenotypes of normal epithelial cells. This enzyme may, therefore, play a role in epithelial physiology and in cell response to certain pathogenic bacteria.

Role of the chymotrypsin-like membrane-associated proteinase from Treponema denticola ATCC 35405 in inactivation of bioactive peptides

The ability of washed whole cells of Treponema denticola ATCC 35405 to hydrolyze (inactivate) substance P, bradykinin, and angiotensin I was studied. Substance P was attacked primarily at the Phe-8-Gly-9 bond by a chymotrypsin-like proteinase (CTLP), at Pro-4-Gln-5 by an endo-acting prolyl oligopeptidase (POPase), and at Gln-5-Gln-6 by an endopeptidase (FALGPA-peptidase). Bradykinin was cleaved at Phe-5-Ser-6 by the FALGPA-peptidase and at Pro-7-Phe-8 by the POPase. Angiotensin I was rapidly converted to angiotensin II by the CTLP, and both angiotensin I and angiotensin II were further hydrolyzed at Pro-7-Phe-8 by the POPase. All these enzymes were assumed to be cell associated and were easily extracted with a mild (0.05 to 0.1%) Triton X-100 treatment. Because it was conceivable that the hydrolysis of substance P at the Phe-8-Gly-9 bond was catalyzed by a CTLP described earlier (V.-J. Uitto, D. Grenier, E. C. S. Chan, and B. C. McBride, Infect. Immun. 56:2717-2722, 1988), the enzyme was purified to homogeneity by means of conventional fast protein liquid chromatography procedures. For kinetic studies, Phe-8(4-nitro)-substance P (NSP) (absorption maximum at 309.2 nm, epsilon = 545 M-1 cm-1) was synthesized to replace substance P as a substrate in kinetic studies. In reversed-phase chromatography, both NSP and substance P gave identical results with both whole cells and the purified enzyme. The CTLP has a mass of 95 kDa, and its activity is suggested to be based on an active seryl residue, on an active imidazole group, and on an active carboxyl group but not on metal cations. The enzyme hydrolyzes N-succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroaniline (SAAPFNA, a typical chymotrypsin substrate) at a high rate and several proteins, such as calf thymus histone, human plasma fibrinogen, milk caseins, and gelatin. Among the substrates tested, substance P showed the highest affinity (Km = 0.22 mM) for the purified enzyme. Depending on conditions, clinically applicable chlorhexidine levels (3.2 mmol/liter, or 0.2%) strongly activated (up to fourfold) the hydrolysis of SAAPFNA by whole cells and the purified CTLP. The hydrolysis of NSP by whole cells and purified CTLP was slightly inhibited by chlorhexidine. The results demonstrated the versatility and the effectiveness of the outer membrane of T. denticola in occasioning a rapid breakdown and inactivation of human bioactive peptides and other peptidolytic catalyses.(ABSTRACT TRUNCATED AT 400 WORDS)