Pupil Dynamics, Salivary Alpha-Amylase, and Prefrontal Haemodynamics in Response to Very Light Exercise.

This study aimed to investigate the effects of exercise on pupil dynamics, prefrontal haemodynamic, and salivary alpha-amylase (sAA) responses in 45 healthy graduate students. These participants were divided into two groups: a resting control group (CTL) and a very-light-intensity exercise group (EX). Participants in the EX-group engaged in a 10-min exercise at 30% O2 peak on a cycle ergometer. Salivary samples and pupillometry assessments were collected before the exercise, at the end of the exercise, and 5 min after the completion to evaluate changes over time. Our analysis showed that exercise induced significant changes in the secretion of salivary alpha-amylase, with elevated levels suggesting increased neuroendocrine activity linked to the arousal state triggered by exercise. In addition, functional oxyHb signals indicated greater fluctuations in the mid-left prefrontal cortex among participants in the EX-group compared to those in the CTL group, pointing to altered prefrontal haemodynamic.

Oxidative damage biomarkers and antioxidant enzymes in saliva of patients with peri-implant diseases.

OBJECTIVES: 8-hydroxydeoxyguanosine (8-OHdG) and Malondialdehyde (MDA) are commonly used as markers to evaluate oxidative DNA and Lipid damage in disorders including chronic inflammatory diseases. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) protect tissues against oxidative injury from free oxygen radicals generated by various metabolic processes. The aim of this study was to evaluate 8-OHdG and MDA levels, and SOD and GPx activities in whole saliva of patients with peri-implant diseases. MATERIALS AND METHODS: A cross-sectional study was conducted on a sum of 60 age gender balanced; peri-implantitis (n = 20), peri-mucositis (n = 20) and healthy (n = 20) individuals. Unstimulated whole saliva samples were collected and to determine the clinical condition of each subject; the plaque index (PI), gingival index (GI), peri-implant probing pocket depth (PIPD), peri-implant presence of bleeding on probing (BOP) (with/without suppuration) and radiographic signs of crestal bone loss (BL) were measured. The salivary 8-OHdG level was measured using the ELISA method. SOD, GPx activities and MDA levels were determined spectrophotometrically. RESULTS: A total of 60 individuals had evaluations of 318 implants. In comparison to the peri-mucositis and peri-implantitis groups, the healthy group had significantly lower PI and GI scores (p < 0.001). The PIPD value differed amongst the groups, with the peri-implantitis group having the highest value (p < 0.001). Compared to the peri-mucositis and control groups, the peri-implantitis group had a significantly higher BL score (p < 0.001 and p < 0.001, respectively). The peri-implantitis group showed a significantly higher 8-OHdG level (p < 0.001; p < 0.001 respectively) than the peri-mucositis and control groups. Compared to the peri-mucositis and control groups, the peri-implantitis group had a significantly higher MDA level (p < 0.001 and p < 0.001, respectively). The peri-implantitis group had a significantly higher SOD level (p < 0.001 and p < 0.001, respectively) in comparison to the peri-mucositis and control groups. There was no significant difference in GPx levels between the peri-mucositis and control groups (p > 0.05), while the peri-implantitis group had significantly lower GPx levels than the peri-mucositis and control groups (p < 0.001 and p < 0.001, respectively). CONCLUSIONS: Elevated levels of oxidative stress in saliva may indicate the onset of pathological bone loss surrounding the implant and may be an indication of peri-implantitis. CLINICAL RELEVANCE: In peri-implant diseases, changes may occur in the levels of 8-OHdG, MDA, SOD and GPx in saliva, which may lead to a deterioration in the oxidant/antioxidant balance.

Lysophospholipase D activity on oral mucosa cells in whole mixed human saliva involves in production of bioactive lysophosphatidic acid from lysophosphatidylcholine.

We reported that lysophosphatidic acid (LPA) is present at 0.8 µM in mixed human saliva (MS). In this study, we examined the distribution, origin, and enzymatic generation pathways of LPA in MS. LPA was distributed in the medium and cell pellet fraction; a true level of soluble LPA in MS was about 150 nM. The soluble LPA was assumed to be generated by ecto-type lysophospholipase D on exfoliated cells in MS from LPC that originated mainly from the major salivary gland saliva. Our results with the albumin-back extraction procedures suggest that a significant pool of LPA is kept in the outer layer of the plasma membranes of detached oral mucosal cells. Such pool of LPA may contribute to wound healing in upper digestive organs including oral cavity. We obtained evidence that the choline-producing activity in MS was mainly due to Ca2+-activated lysophospholipase D activity of glycerophosphodiesterase 7.

Light-Controlled Regulation of Dual-Enzyme Properties in YbGd-Carbon Quantum Dots Nano-Hybrid for Advanced Biosensing.

Compared to nanozymes with single enzyme activity, those with multiple enzyme activities possess broader application potential due to their diversified enzymatic functionalities. However, the multienzyme nanozymes currently face challenges of interference among different enzymatic activities during practical applications. In this study, we report the synthesis of a light-responsive YbGd-carbon quantum dots nano-hybrid, termed YbGd-CDs, which exhibits controllable enzyme-mimicking activities. This light-responsive behavior enables selective control of the enzymatic activities. Under visible light irradiation, YbGd-CDs demonstrate robust oxidase-like activity. Conversely, under dark conditions, they primarily exhibit peroxidase-like activity. Leveraging the dual-enzyme-mimicking capabilities of YbGd-CDs, we developed colorimetric assays for sensitive detection of total antioxidant capacity (TAC) in both normal and cancer cells as well as d-amino acids in human saliva. This study not only advances the synthesis of carbon-based nanozymes but also highlights their potential in biosensing applications.

Intrinsic oxidase-mimicking activity of nitrite upon visible light illumination and its colorimetric detection in saliva.

Small molecules with enzyme-like properties have recently attracted considerable attention. Herein, we discovered that nitrite possesses intrinsic oxidase-mimicking activity upon visible light, catalyzing the oxidation of the typical chromogenic substrate in the absence of H2O2. Notably, nitrite exhibited a markedly high value of Kcat, approximately 4, 7, and 4000-fold greater than that of Acr+-Mes, Eosin Y, and Diacetyl, respectively. Comprehensive investigation elucidated that O2•⁻ and •OH are the primary reactive oxygen species (ROS) responsible for the oxidation of 3,3',5,5'-tetramethylbenzidine dihydrochloride hydrate (TMB). Leveraging the linear correlation between the absorbance of oxidized TMB (oxTMB) at 652 nm and nitrite concentration, a simple colorimetric approach for nitrite detection was successfully established in the range of 1-75 µM with a detection limit of 0.14 µM. Moreover, the proposed strategy could be applied to determine the nitrite concentration in saliva, exhibiting a great prospect for clinical diagnosis. This work contributes novel insights into the exploration of small-molecule enzyme mimics.

Changes in cortisol, cortisone and 11ß-hydroxysteroid dehydrogenase type II activity in saliva during pregnancy and lactation in sows.

The activity of the enzyme 11ß-hydroxysteroid dehydrogenase type II (11ß-HSD type II), which can be estimated by the combined measurement of cortisol and cortisone, is gaining importance as a marker for the assessment of stress in pigs. The aim of this study was to investigate the activity of this enzyme and the salivary concentrations of cortisol and cortisone in pigs during pregnancy, farrowing and lactation and to compare it with other stress-related biomarkers such as Chromogranin A (CgA), S100A12 and alpha-amylase. Salivary cortisone concentrations and 11ß-HSD type II activity decreased after farrowing, while cortisol concentrations increased. Enzyme activity did not show significant correlations with any of the other stress-related biomarkers measured in this study. Overall, the results of this report indicate a different regulation of 11ß-HSD type II activity and of cortisol and cortisone during pregnancy and lactation, which should be considered when evaluating these analytes in saliva during these periods.

Is Salivary Α-Amylase a Reliable Indicator of Psychological Status and Quality of Life in Patients with Oral Lichen Planus: a Case-Control Study.

BACKGROUND/AIMS: The objectives of our study were to determine salivary α-amylase activity (stress biomarker) and its association with psychological status and quality of life (QoL), disease duration and intensity of symptoms (pain/burning) in patients with OLP. METHODS: A total of 50 subjects participated in this case-control study: 30 patients with oral lichen planus (OLP); 20 control subjects. Unstimulated whole saliva (UWS) was collected between 9 and 10 am to avoid diurnal fluctuations. Psychological status was assessed using the Croatian validated version of the original Depression, Anxiety and Stress Scale (DASS-21). The impact of oral health on QoL was assessed using the Croatian version of the Oral Health Impact Profile Questionnaire (OHIP-CRO14). RESULTS: There was no statistically significant difference in salivary α-amylase activity between patients with OLP (N=30) and control subjects (N=20) (133813.3 vs. 166815.5 U/L, p=0.314; t-test). Depression, anxiety and stress showed no statistically significant difference between patients with OLP and control subjects (p=0.076, p=0.111, p=0.209; t-test). The patients with OLP had statistically significantly poorer QoL (total) compared to control subjects (p=0.004, t-test). There was a moderate positive correlation between symptom intensity (pain/burning) and poor QoL (total) (r=0.584, p<0.001), the OHIP-CRO14 dimension "physical pain" (r=0.661, p<0.001), "psychological impossibility" (r=0.555, p<0.01), "handicap" (r=0.546, p<0.01). CONCLUSION: Although salivary α-amylase showed no statistically significant difference between patients with OLP and control subjects, the patients with OLP had poorer psychological status (three times higher scores for depression and two times higher scores for anxiety) and poorer QoL compared to the control subjects. Recognising and treating mental disorders in patients with OLP is important in order to break the "vicious circle" and achieve a better QoL in these patients.

Scavenging H2O2 of plant host by saliva catalase of leafhopper vector benefits viral transmission.

Catalase (CAT) is the main reactive oxygen species (ROS)-scavenging enzyme in plants and insects. However, it remains elusive whether and how insect saliva CAT suppresses ROS-mediated plant defense, thereby promoting initial virus transmission by insect vectors. Here, we investigated how leafhopper Recilia dorsalis catalase (RdCAT) was secreted from insect salivary glands into rice phloem, and how it was perceived by rice chaperone NO CATALASE ACTIVITY1 (OsNCA1) to scavenge excessive H2O2 during insect-to-plant virus transmission. We found that the interaction of OsNCA1 with RdCAT activated its enzymatic activity to decompose H2O2 in rice plants during leafhopper feeding. However, initial insect feeding did not significantly change rice CATs transcripts. Knockout of OsNCA1 in transgenic lines decreased leafhopper feeding-activated CAT activity and caused higher H2O2 accumulation. A devastating rice reovirus activated RdCAT expression and promoted the cosecretion of virions and RdCAT into leafhopper salivary cavities and ultimately into the phloem. Virus-mediated increase of RdCAT secretion suppressed excessive H2O2, thereby promoting host attractiveness to insect vectors and initial virus transmission. Our findings provide insights into how insect saliva CAT is secreted and perceived by plant chaperones to suppress the early H2O2 burst during insect feeding, thereby facilitating viral transmission.

Structure-function relationships in (poly)phenol-enzyme binding: Direct inhibition of human salivary and pancreatic α-amylases.

(Poly)phenols inhibit α-amylase by directly binding to the enzyme and/or by forming starch-polyphenol complexes. Conventional methods using starch as the substrate measure inhibition from both mechanisms, whereas the use of shorter oligosaccharides as substrates exclusively measures the direct interaction of (poly)phenols with the enzyme. In this study, using a chromatography-based method and a short oligosaccharide as the substrate, we investigated the detailed structural prerequisites for the direct inhibition of human salivary and pancreatic α-amylases by over 50 (poly)phenols from the (poly)phenol groups: flavonols, flavones, flavanones, flavan-3-ols, polymethoxyflavones, isoflavones, anthocyanidins and phenolic acids. Despite being structurally very similar (97% sequence homology), human salivary and pancreatic α-amylases were inhibited to different extents by the tested (poly)phenols. The most potent human salivary α-amylase inhibitors were luteolin and pelargonidin, while the methoxylated anthocyanidins, peonidin and petunidin, significantly blocked pancreatic enzyme activity. B-ring methoxylation of anthocyanidins increased inhibition against both human α-amylases while hydroxyl groups at C3 and B3' acted antagonistically in human salivary inhibition. C4 carbonyl reduction, or the positive charge on the flavonoid structure, was the key structural feature for human pancreatic inhibition. B-ring glycosylation did not affect salivary enzyme inhibition, but increased pancreatic enzyme inhibition when compared to its corresponding aglycone. Overall, our findings indicate that the efficacy of interaction with human α-amylase is mainly influenced by the type and placement of functional groups rather than the number of hydroxyl groups and molecular weight.

Sucrose rinse modulates the salivary behavior of carbonic anhydrase VI and its buffering capacity: a longitudinal study in 4 to 6.5-year-old children.

Background: Carbonic anhydrase VI (CA VI) is crucial in regulating oral pH and predicting susceptibility to dental caries. The hypothesis posits that caries activity may alter the CA VI function, diminishing its capacity to regulate pH effectively and potentially exacerbating cariogenic challenges. This 1-year cohort study sought to investigate the enzymatic activity of salivary CA VI and buffering capacity following a 20% sucrose rinse in 4 to 6.5-year-old children. Method: This research involved 46 volunteers categorized into three groups based on their caries status after follow-up: caries-free (CFee), arrested caries (CArrested), and caries active (CActive). Children underwent visible biofilm examination and saliva collection for salivary flow rate, buffering capacity, and CA VI analyses before and after a 20% sucrose rinse. Results: A reduction in the buffering capacity was observed after sucrose rinse in all groups. The CA VI activity decreased significantly in CFee and CArrested groups after sucrose rinse, although it did not change in the CActive group. An improvement in the buffering capacity and salivary flow rate was found at follow-up when compared with the baseline. After 1-year follow-up, buffering capacity and salivary flow rate increased in all groups, whilst the CA VI activity reduced only in CFree and CArrested children. Conclusion: Sucrose rinse universally reduces the salivary buffering capacity, while caries activity may disrupt CA VI activity response during a cariogenic challenge. After a year, increased salivary flow enhances buffering capacity but not CA VI activity in caries-active children.

Diagnostic accuracy of salivary active matrix metalloproteinase (aMMP)-8 point-of-care test for detecting periodontitis in adults: A systematic review and meta-analysis.

OBJECTIVE: To determine the accuracy of salivary active matrix metalloproteinase (aMMP)-8 point-of-care test (POCT) for detecting periodontitis in adults, through meta-analysis. MATERIALS AND METHODS: Diagnostic studies evaluating the accuracy of salivary/oral rinse aMMP-8 POCT for detecting periodontitis in adults, when compared with clinical examination, were considered eligible. A comprehensive search was performed up to 31 August 2023 through five databases. Quality Assessment of Diagnostic Accuracy Studies 2 was utilized to evaluate the methodological quality of the included articles. Meta-analysis was performed using Bayesian bivariate hierarchical model and subgroup analysis. RESULTS: From 368 screened studies, 6 studies (4 cross-sectional and 2 longitudinal studies) were included in the meta-analysis. Overall, the pooled sensitivity and specificity of salivary aMMP-8-POCT for detecting periodontitis were 0.63 (95% CI: 0.41-0.82) and 0.84 (95% CI: 0.65-0.95), respectively. Subgroup analyses revealed that the 95% CI for oral fluid types, predefined diagnostic thresholds and the POCT systems largely overlapped, indicating that the differences between them may not be significant. CONCLUSION: Salivary aMMP-8 POCT shows fair accuracy for detecting periodontitis. The diagnostic accuracy cannot be significantly influenced by the types of oral fluids, predefined diagnostic thresholds or the specific POCT systems used. More research is needed to confirm the clinical utility and implementation of aMMP-8 POCT in the diagnosis of periodontitis.

Turn-off enzyme activity of histidine-rich peptides for the detection of lysozyme.

An assay that integrates histidine-rich peptides (HisRPs) with high-affinity aptamers was developed enabling the specific and sensitive determination of the target lysozyme. The enzyme-like activity of HisRP is inhibited by its interaction with a target recognized by an aptamer. In the presence of the target, lysozyme molecules progressively assemble on the surface of HisRP in a concentration-dependent manner, resulting in the gradual suppression of enzyme-like activity. This inhibition of HisRP's enzyme-like activity can be visually observed through color changes in the reaction product or quantified using UV-visible absorption spectroscopy. Under optimal conditions, the proposed colorimetric assay for lysozyme had a detection limit as low as 1 nM and exhibited excellent selectivity against other nonspecific interferents. Furthermore, subsequent research validated the practical applicability of the developed colorimetric approach to saliva samples, indicating that the assay holds significant potential for the detection of lysozymes in samples derived from humans.

Salivary Proteinase 3 as a Biomarker for Caries Severity in Children: A Cross-sectional Study.

AIM: This study aims to evaluate the relation between salivary proteinase 3 (PR3) concentration and caries severity in children. MATERIALS AND METHODS: Six-to-eight-year age group children, from the Outpatient Department of Pediatric and Preventive dentistry at PMS Dental College were selected for the study. From these children, three groups each consisting of 28 children were selected according to the dental caries severity. Three groups were: (1) No Dental Caries group, (2) Low Dental Caries group with DMFT/DEFT score of 1-4, and (3) High Dental Caries group with DMFT/DEFT score of 5-15. Thus, a total of 84 children who satisfied the inclusion criteria were selected. The concentration of PR3 in saliva of the donors were analyzed using an ELISA kit. One way ANOVA was used for finding the relation of salivary PR3 concentration with caries severity. Pairwise comparison of PR3 concentration and caries severity were analyzed using post hoc Tukey test. RESULTS: Severity of caries and concentration of salivary PR3 showed an inverse relation. As the caries severity increases there was a decrease in PR3 concentration and vice versa. CONCLUSION: The children with high caries severity showed lower concentration of PR3 in their saliva compared with those with lower caries severity which indicates that PR3 can be used as a biomarker for assessing caries severity and also paves way to use PR3 as a caries vaccine in future. Nowadays, interest toward noninvasive and personalized dentistry has been increased. Molecular assays using salivary biomarkers can be an effective tool in detecting the caries in earlier stages and assessing a patient's caries risk. CLINICAL SIGNIFICANCE: Salivary PR3 can be used as prognostic biomarker for assessing caries severity and after treatment the value of PR3 can be used as a assessment tool to confirm its relation with caries. How to cite this article: Karthika S, George S, Soman A, et al. Salivary Proteinase 3 as a Biomarker for Caries Severity in Children: A Cross-sectional Study. J Contemp Dent Pract 2024;25(3):236-240.

Salivary, acidic and enzymatic degradation of resin composite subjected to different finishing and polishing systems.

PURPOSE: To evaluate the effect of different finishing and polishing systems on the surface roughness of a resin composite subjected to simulated saliva-, acid-, and enzyme-induced degradation. METHODS: 160 specimens (n= 40) were fabricated with Filtek Z350 XT nanofilled composite and analyzed for average surface roughness (Ra). The specimens were finished and polished using: AD - Al2O3-impreginated rubberized discs (medium, fine, and superfine grit, Sof-Lex); SD - silicon carbide and Al2O3-impregnated rubberized discs (coarse, medium and fine grit, Jiffy,); MB - 12- and 30-multiblade burs. The control group (CT) (n= 40) comprised specimens with a Mylar-strip-created surface. Specimens from each group were immersed in 1 mL of one of the degradation methods (n= 10): artificial saliva (ArS: pH 6.75), cariogenic challenge (CaC: pH 4.3), erosive challenge (ErC: 0.05M citric acid, pH 2.3) or enzymatic challenge (EzC: artificial saliva with 700 µg/mL of albumin, pH 6.75). The immersion period simulated a time frame of 180 days. Ra measurements were also performed at the post-polishing and post-degradation time points. The data were evaluated by three-way ANOVA for repeated measures and the Tukey tests. RESULTS: There was significant interaction between the finishing/polishing system and the degradation method (P= 0.001). AD presented the greatest smoothness, followed by SD. After degradation, CT, AD and SD groups became significantly rougher, but not the MB group, which presented no difference in roughness before or after degradation. CT and AD groups showed greater roughness in CaC, ErC and EzC than in ArS. The SD group showed no difference in roughness when the specimens were polished with CaC, EzC or ArS, but those treated with ErC had greater roughness. In the MB group, the lower roughness values were found after using CaC and EzC, while the higher values were found using ErC or ArS. CLINICAL SIGNIFICANCE: As far as degradation resistance of nanofilled composite to hydrolysis, bacterial and dietary acids and enzymatic reactions is concerned, restorations that had been finished and polished with Al2O3-impregnated discs had the smoothest surfaces.

The use of bioluminescent enzyme bioassay for the analysis of human saliva: Advantages and disadvantages.

The purpose of the work was to find optimal conditions for bioluminescent enzymatic analysis of saliva (based on the use of NADH:FMN oxidoreductase + luciferase) and then to determine the biological effect of using bioluminescence assay of saliva to study the physiological state of the body under normal and pathological conditions. The saliva of snowboarders and students were studied in the "rest-training" model. The saliva of patients diagnosed with acute pharyngitis was examined in the "sick-healthy" model. Bioluminescence assay was performed with a lyophilized and immobilized bi-enzyme system using cuvette, plate, and portable luminometers. The concentrations of secretory immunoglobulin A (sIgA) and cortisol were determined by enzyme immunoassay, and the total protein content was measured by spectrophotometric method. The activity of the bioluminescent system enzymes increased as the amount and volume of saliva in the sample was decreased. The cuvette and plate luminometers were sensitive to changes in the luminescence intensity in saliva assay. Luminescence intensity correlated with the concentrations of sIgA and cortisol. The integrated bioluminescent index for saliva was reduced in the "rest-training" model and increased in the "sick-healthy" model. Thus, the non-invasive bioluminescent saliva analysis may be a promising tool for assessing the health of the population.

Honeycomb-Inspired Surface-Enhanced Raman Scattering Microarray for Large-Area Automated Testing of Urease in Saliva Samples.

Surface-enhanced Raman scattering (SERS) technology, as an important analytical tool, has been widely applied in the field of chemical and biomedical sensing. Automated testing is often combined with biochemical analysis technologies to shorten the detection time and minimize human error. The present SERS substrates for sample detection are time-consuming and subject to high human error, which are not conducive to the combination of SERS and automated testing. Here, a novel honeycomb-inspired SERS microarray is designed for large-area automated testing of urease in saliva samples to shorten the detection time and minimize human error. The honeycomb-inspired SERS microarray is decorated with hexagonal microwells and a homogeneous distribution of silver nanostars. Compared with the other four common SERS substrates, the optimal honeycomb-inspired SERS microarray exhibits the best SERS performance. The RSD of 100 SERS spectra continuously collected from saliva samples is 6.56%, and the time of one detection is reduced from 5 min to 10 s. There is a noteworthy linear relationship with a R2 of 0.982 between SERS intensity and urease concentration, indicating the quantitative detection capability of the urease activity in saliva samples. The honeycomb-inspired SERS microarray, combined with automated testing, provides a new way in which SERS technology can be widely used in biomedical applications.

Salivary and serum levels of lactate dehydrogenase in oral submucous fibrosis: A meta-analysis.

BACKGROUND: The occurrence of oral submucous fibrosis (OSF) is often accompanied by an increase in lactate dehydrogenase (LDH) levels. In this meta-analysis, we compared the salivary and serum levels of LDH levels between OSF patients and controls. MATERIAL AND METHODS: A comprehensive search was conducted in PubMed, Embase, Web of Science, and Cochrane Library from the establishment of the database to June 2023, and the quality of the studies was checked by the Newcastle-Ottawa Quality Assessment scale. The mean difference (MD) and 95% confidence interval (CI) were calculated using RevMan 5.4 software. RESULTS: A total of 28 studies were retrieved from the database, and we included 5 studies in this meta-analysis. The salivary LDH level of OSF patients was higher than healthy controls (MD: 423.10 pg/L 95%CI: 276.42-569.77 pg/mL, P < .00001), the serum LDH level of OSF patients was also higher than that of healthy controls (MD: 226.20 pg/mL, 95%CI: 147.71-304.69 pg/mL, P < .00001). CONCLUSIONS: This meta-analysis showed that salivary and serum LDH levels were higher in OSF patients than in healthy controls, suggesting that LDH may be a potential biomarker for OSF.

Effects of Zinc Compounds on the Enzymatic Activities of Lysozyme and Peroxidase and Their Antifungal Activities.

This study aimed to investigate the effects of zinc compounds on the enzymatic activities of lysozyme, peroxidase, and the glucose oxidase-mediated peroxidase (GO-PO) system and their antifungal activities. Four different zinc compounds (zinc chloride, gluconate, lactate, and sulfate) were incubated with hen egg-white lysozyme (HEWL), bovine lactoperoxidase (bLPO), the GO-PO system, and human unstimulated whole saliva in solution and on a hydroxyapatite surface. Enzymatic activities of lysozyme, peroxidase, and the GO-PO system were measured through the hydrolysis of Micrococcus lysodeikticus, oxidation of fluorogenic 2',7'-dichlorofluorescin, and glucose assay, respectively. Interactions between zinc and enzymes were analyzed by surface plasmon resonance (SPR). The minimum inhibitory concentration (MIC) and candidacidal activities of zinc compounds were examined against three Candida albicans strains. Zinc gluconate and sulfate significantly increased the enzymatic activities of salivary lysozyme in the solution assay and of HEWL and salivary lysozyme on the hydroxyapatite surface. However, all examined zinc compounds significantly decreased the enzymatic activities of bLPO and salivary peroxidase in solution and on the surface. SPR analyses revealed binding of zinc to lysozyme and peroxidase, with affinity differing according to the zinc compounds. The MIC of zinc compounds against C. albicans was 1.0-2.4 mM. Candidacidal activities were 17.7-38.8% and 23.7-47.0% at 1.0 and 10 mM concentrations, respectively. In conclusion, zinc compounds enhanced lysozyme activity but inhibited peroxidase activity. Zinc compounds exhibited concentration-dependent candidacidal activity against C. albicans. Zinc compounds are potential therapeutic agents for oral health, especially for geriatric patients.

Detection and enzymatic characterization of human saliva amylase.

As a rule, an experiment carried out at school or in undergraduate study courses is rather simple and not very informative. However, when the experiments are to be performed using modern methods, they are often abstract and difficult to understand. Here, we describe a quick and simple experiment, namely the enzymatic characterization of ptyalin (human salivary amylase) using a starch degradation assay. With the experimental setup presented here, enzyme parameters, such as pH optimum, temperature optimum, chloride dependence, and sensitivity to certain chemicals can be easily determined. This experiment can serve as a good model for enzyme characterization in general, as modern methods usually follow the same principle: determination of the activity of the enzyme under different conditions. As different alleles occur in humans, a random selection of test subjects will be quite different with regard to ptyalin activities. Therefore, when the students measure their own ptyalin activity, significant differences will emerge, and this will give them an idea of the genetic diversity in human populations. The evaluation has shown that the pupils have gained a solid understanding of the topic through this experiment.

Is adenosine deaminase (ADA) activity in saliva and serum a more accurate disease detection tool than traditional redox balance parameters in early-lactating dairy cows?

Enzyme adenosine deaminase (ADA) is a marker of inflammation in domestic animals, but it is unclear whether it is a reliable marker of oxidative stress, especially in the transition period in dairy cows. This study aims to assess if ADA and redox status measurements in saliva provide the same utility to detect disease condition as that obtained from serum. Sixty-eight multiparous Holstein cows, between 2 and 3 weeks postpartum were selected. Five study groups were established: control (healthy), and cows with ketosis, mastitis, laminitis, and metritis. The parameters measured were ADA activity, total oxidants (TOS), antioxidants (TAC), and OSi ratio.Regarding redox status, no significant differences arise in both saliva and serum being the correlations negative and not significant. In saliva, ADA activity in healthy cows differs from those with pathological processes, having the lowest activities. In serum, ADA activity is similar in the healthy and ketosis cows, showing the lowest activities meanwhile animals with mastitis, laminitis, or metritis have significantly higher activities. In conclusion, the measurement of ADA activities and redox status in saliva does not give consistent results, being preferable to measure them in serum during the transition period.