Coronavirus disease 2019 (COVID-19) is a highly contagious illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This disease is characterized by a wide spectrum of symptoms, ranging from mild to severe, including fatal outcomes. This study aims to review gustatory and salivary secretion dysfunctions and determine their potential pathogenic mechanisms. Gustatory impairment and salivary dysfunction are prevalent among patients with acute COVID-19 and those recovering from the disease. The mouth serves as a critical entry route for SARS-CoV-2. The cells within the oral epithelium, taste buds, and minor and major salivary glands express key entry factors for SARS-CoV-2, including angiotensin-converting enzyme 2, transmembrane serine protease 2, and furin. The co-occurrence of gustatory and salivary secretion dysfunctions possibly has pathogenetic association with the following factors: the expression of SARS-CoV-2 cellular entry receptors in the taste buds and salivary glands and SARS-CoV-2–induced zinc deficiency, which is crucial for normal taste perception and saliva secretion. Furthermore, the cytokine storm triggered by COVID-19 contributes to secondary damage affecting gustatory and salivary functions.

Graphene is a suitable transducer for wearable sensors because of its high conductivity, large specific surface area, flexibility, and other unique considerable features. Using a simple, fast galvanic pulse electrodeposition approach, a unique nonenzymatic glucose amperometric electrode was successfully developed based on well-distributed fine Cu nanoparticles anchored on the surface of 3D structure laser-induced graphene. The fabricated electrode allows glucose detection with a sensitivity of 2665 μA/mM/cm2, a response time of less than 5 s, a linear range of 0.03–4.5 mM, and a LOD of 0.023 μM. It also detects glucose selectively in the presence of interfering species such as ascorbic acid and urea. These provide the designed electrode the advantages for glucose sensing in saliva with 97% accuracy and present it among the best saliva-range non-enzymatic glucose sensors reported to date for real-life diagnostic applications.

The purpose of this study is to develop a pH measurement system capable of measuring the acidity of saliva to check the change in pH level in saliva during driving and to detect whether fatigue is affected. When the pH level is checked at rest and operation, and oxygen concentration is supplied additionally, it will be verified whether the fatigue is reduced. It is reported that the pH level in saliva is divided into stages from 0 to 14, and the lower the value based on step 7, the higher the fatigue, and the lower the fatigue. In particular, in enclosed vehicles, drowsiness and fatigue due to increased carbon dioxide have increased, leading to a major cause of traffic accidents. Therefore, fatigue may be detected in advance by analyzing fatigue through a change in pH level by supplying oxygen during operation. The electromotive force generated by the existing itself is a level of several mV to develop a pH measurement system, so it is developed by expanding it to a range that can be measured using a readout circuit. In the experiment, 13 male experimenters in their 20s measured pH levels in resting and driving conditions. After 20 minutes of rest, the process of inhaling oxygen for 20 minutes was repeated three times. The oxygen concentration used in the experiment was 21% oxygen and 30% oxygen concentration in the atmospheric state, and in the oxygen supply method, a triangular flask was directly connected to the subject’s nose and then oxygen was supplied. As a result of collecting and analyzing saliva after rest and operation, it was confirmed that the pH level tended to decrease in the operating state. In addition, as a result of increasing the pH level when the oxygen concentration is 30% more than 21%, it is confirmed that fatigue tends to decrease as the oxygen concentration increases. Therefore, it was possible to confirm a significant change in fatigue by analyzing the pH level of saliva through this pH measurement system. This study can be used as a fatigue test in various environments through simple pH measurement.

Since the outbreak of coronavirus disease 2019 (COVID-2019), the infection has spread worldwide due to the highly contagious nature of severe acute syndrome coronavirus (SARS-CoV-2). To manage SARS-CoV-2, the development of diagnostic assays that can quickly and accurately identify the disease in patients is necessary. Currently, nucleic acid-based testing and serology-based testing are two widely used approaches. Of these, nucleic acid-based testing with quantitative reverse transcription-PCR (RT-qPCR) using nasopharyngeal (NP) and/or oropharyngeal (OP) swabs is considered to be the gold standard. Recently, the use of saliva samples has been considered as an alternative method of sample collection. Compared to the NP and OP swab methods, saliva specimens have several advantages. Saliva specimens are easier to collect. Self-collection of saliva specimens can reduce the risk of infection to healthcare providers and reduce sample collection time and cost. Until recently, the sensitivity and accuracy of the data obtained using saliva specimens for SARS-CoV-2 detection was controversial. However, recent clinical research has found that sensitive and reliable data can be obtained from saliva specimens using RT-qPCR, with approximately 81% to 95% correspondence with the data obtained from NP and OP swabs. These data suggest that self-collected saliva is an alternative option for the diagnosis of COVID-19.

Xylitol is well-known to have an anti-caries effect by inhibiting the replication of cariogenic bacteria. In addition, xylitol enhances saliva secretion. However, the precise molecular mechanism of xylitol on saliva secretion is yet to be elucidated. Thus, in this study, we aimed to investigate the stimulatory effect of xylitol on saliva secretion and to further evaluate the involvement of xylitol in muscarinic type 3 receptor (M3R) signaling. For determining these effects, we measured the saliva flow rate following xylitol treatment in healthy individuals and patients with dry mouth. We further tested the effects of xylitol on M3R signaling in human salivary gland (HSG) cells using realtime quantitative reverse-transcriptase polymerase chain reaction, immunoblotting, and immunostaining. Xylitol candy significantly increased the salivary flow rate and intracellular calcium release in HSG cells via the M3R signaling pathway. In addition, the expressions of M3R and aquaporin 5 were induced by xylitol treatment. Lastly, we investigated the distribution of M3R and aquaporin 5 in HSG cells. Xylitol was found to activate M3R, thereby inducing increases in Ca2+ concentration. Stimulation of the muscarinic receptor induced by xylitol activated the internalization of M3R and subsequent trafficking of aquaporin 5. Taken together, these findings suggest a molecular mechanism for secretory effects of xylitol on salivary epithelial cells.

Exosomes are Nano-sized lipid vesicles secreted from mammalian cells containing diverse cellular materials such as proteins, lipids, and nucleotides. Multiple lines of evidence indicate that in saliva, exosomes and their contents such as microRNAs (miRNAs) mediate numerous cellular responses upon delivery to recipient cells. The objective of this study was to characterize the different expression profile of exosomal miRNAs in saliva samples, periodically isolated from a single periodontitis patient. Unstimulated saliva was collected from a single patient over time periods for managing periodontitis. MicroRNAs extracted from each phase were investigated for the expression of exosomal miRNAs. Salivary exosomal miRNAs were analyzed using Affymetrix miRNA arrays and prediction of target genes and pathways for its different expression performed using DIANA-mirPath, a web-based, computational tool. Following the delivery of miRNA mimics (hsa-miR-4487, -4532, and -7108-5p) into human gingival fibroblasts, the expression of pro-inflammatory cytokines and activation of the MAPK pathway were evaluated through RT-PCR and western blotting. In each phase, 13 and 43 miRNAs were found to be differently expressed (|FC| ≥ 2). Among these, hsa-miR-4487 (|FC|=9.292005) and hasmiR- 4532 (|FC|=18.322697) were highly up-regulated in the clinically severe phase, whereas hsa-miR-7108-5p (|FC|= 12.20601) was strongly up-regulated in the clinically mild phase. In addition, the overexpression of miRNA mimics in human gingival fibroblasts resulted in a significant induction of IL-6 mRNA expression and p38 phosphorylation. The findings of this study established alterations in salivary exosomal miRNAs which are dependent on the severity of periodontitis and may act as potential candidates for the treatment of oral inflammatory diseases.

During tick infestation, the tick secretes bioactive substances that modify the host’s physiological and immunological reactions. The study of tick saliva is important to understand tick biology as tick saliva plays a special physiological role in pathogen transmission. The average salivary protein concentration was found to be 0.169 μg/μl/tick and saliva secretion decreased with increased time of tick detachment from the host. Saliva secretion volume increased to 3.56 μl in the group of ticks with a body weight between 301–350 mg as compared to higher and lower body weight groups. On-chip-electrophoresis results show 13 distinct bands ranging from 9.9 to 294 kDa. For salivary protein LC-MS/MS was performed. A total of 135 tick salivary proteins were identified of which 30 proteins were found exclusively in fully engorged nymph saliva, 74 in fully engorged adult females, and 31 were detected in both stages. Results of this may help researchers to identify tick proteins as potential candidates for further studies aimed to develop novel tick control strategies to affect both the ticks and the pathogens transmitted by them.

The purpose of this study is to evaluate salivary flow rate, salivary pH, and cariogenic activity using unstimulated saliva of the head and neck cancer patients. Twenty three cancer patients (19 males, 4 females) who had undergone chemotherapy and radiation therapy and twenty four healthy volunteers (14 males, 10 females) as a control were included. Salivary flow rate, salivary pH, and cariogenic activity using unstimulated saliva were examined. Compared to saliva of the control group, salivary flow rate (p<0.001) and salivary pH (p<0.001) were significantly lower in head and neck cancer patients. The colony counts of Lactobacilli was higher in head and neck cancer patients (p<0.05) than in control group. These salivary factors and cariogenic activity can increase the prevalence of dental caries in head and neck cancer patients.

A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick. They are used to determine physiological and biochemical states, such as disease, mineral contents, drug effectiveness, and organ function. Although the term blood test is used, most routine tests (except for most haematology) are done on plasma or serum, instead of blood cells. Main advantage of using saliva in diagnostics is easy and non invasive sample taking compared to peripheral blood. According to the study published, saliva contains more than 20 percent of the proteins found in blood. The purpose of present study is to compare biochemical enzymes in saliva and in blood serum and to evaluate the usefulness of saliva specimens instead of blood in dental clinic. The saliva from 215 healthy over 50 years of aged people lived in Dong-gu district, Gwangu city was collected and the analysis was performed by six enzyme-linked immunosorbent assays (ELISA). ELISA results were compared with blood chemistry results. The values or patterns on Alanine Aminotransperase (ALT), Aspartate Aminotransperase (AST), Cholesterol and Triglyceride in saliva were not correlated with those in blood serum. However, Albumine and γ-glutamyl transpeptidase (γ-GTP) were followed the positive relationship with blood chemistry. These result showed that detection and identification of Albumine and γ-GTP level could be established by saliva ELISA analysis, so that ELISA assay on saliva could be useful alternative to serum testing.

Candida albicans and their associated Candida species are opportunistic pathogens which exists as normal flora in the oral cavities of healthy individuals. In response to physiological changes in the host, these yeasts can become pathogenic, resulting in oral candidiasis. The rapid detection and identification of Candida species in clinical laboratories are extremely important for the management of patients with hematogenous candidiasis. The presently available culture and biochemical methods for detection and species identification of Candida are time-consuming and lack the required sensitivity and specificity. In this study, we have established a seminested PCR (snPCR) using universal and species-specific primers for detection of Candida species in saliva. The universal outer primers amplified the 3end of 5.8S ribosomal DNA (rDNA) and the 5end of 28S rDNA, including the internally transcribed spacer 2 (ITS2), generating 350- to 410-bp fragments from the four commonly encountered Candida spp., viz., C. albicans, C. tropicalis, C. glabrata, and C. parapsilosis. The saliva from 331 healthy and, over 50 years of aged people lived in Dong-gu, Gwangu city, was collected. Total DNA were extracted by Hoffman-Winston yeast total DNA prep. method and performed t he s nP CR. R esults appeared to b e negative on 292 people ( 88.2%), however, 2 6 people ( 7.9%) were p ositive Candida albicans, 6 people (1.8%) were positive Candida glabrata, 5 people (1.5%) were positive Candida tropicalis, and only 2 person (0.6%) were positive Candida parapsilosis. These result showed that detection and identification of Candida species could be established by saliva analysis, so that snPCR on saliva is useful method of diagnosis of clinical fields

As the human mixed saliva plays important roles for the protection, regeneration, immunity, and molecular transfer/ signaling in the oral and gastro-intestinal mucosa, the salivary contents have great implications for the general health of human body. Nevertheless, the analysis method of human saliva has not been well developed up to date, because the proteins of mixed saliva are rapidly interacted with each other and easily degraded by proteolytic enzymes and microorganisms. This study aims to develop an immunoprecipitation-based high performance liquid chromatography (IP-HPLC) for the analysis of human mixed saliva. The representative IP-HPLC analyses were performed to compare among different subjects in variable general conditions. Compared to the normal control the subjects suffered from bacterial infections of gastro-intestinal enteritis, chronic periodontitis, and acute necrotizing gingivo-stomatitis showed dramatic increase of LL-37 level depending on the severity of diseases, while the subject suffered from Herpes stomatitis, a viral infection showed great increase of β-defensin 2. These data indicate that LL-37 in human mixed saliva is more responsible to the bacterial infections of gastro-intestinal enteritis, chronic periodontitis, and acute necrotizing gingivo-stomatitis, while β-defensin 2 is more responsible to the viral infection of Herpes stomatitis. This study also suggeststhat the IP-HPLC be easily applicable to the wide range of biological samples for the quantitative analysis of an objective protein.

Biolog ECO plates (31 different carbon sources, Biolog Inc., Hayward, USA) were used to discriminate between rhizosphere soil samples from 4- and 9-year alfalfa stands each with three replication. The growth curves for different groups of carbon sources were nearly sigmoidal, but the maximum rate of utilization was faster for amino acids, carbohydrates and polymers t㏊n for amides, miscellaneous and carboxylic acids, and carbon sources utilization efficiency were all higher in 9-year t㏊n in 4-year alfalfa stand.

In this study, calcium titanate (CaTiO3) gel was prepared by mixing calcium nitrate and titanium isopropoxide in 2-methoxy-ethanol. CaTiO3 gel was single-layer coated on Ti-6Al-4V using a sol-gel dip-coating technique. The coating was calcined at 750˚C in air by utilizing a very slow heating rate of 2˚C/min. The crystalline phases of the coating were characterized by x-ray diffraction using a slow scan rate of 1˚/min. The morphology of the coating was analyzed by scanning electron microscopy. The corrosion behavior of Ti-6Al-4V samples coated with CaTiO3 films were tested in an artificial saliva solution by potentiodynamic polarization and were quantified by the Tafel extrapolation method. The electrochemical parameters showed a considerable increase in the corrosion resistance for the CaTiO3-coated Ti-6Al-4V samples compared to bare substrates.

Human saliva contains a large number of proteins and peptides whose composition may alter as a consequence 。f disease. To date. however‘ the proteins and peptides that routinely populate thi s ora l fluid a re largely unknown To provide a catalogue of saliva proteins, we have surveyed the unstimulated human whole saliva by us ing shotgun proteornics. For the shotgun approach, whole saliva proteins were digested into peptides with ChemDigestD ‘ and the resul ting peptide fragments were separated by RP-HPLC, followed by each fraction was t ryptic digestion. ChemDigestD-Trypsin digested peptides were analyzed by tandem mass spectrometry(MS/MS) us ing a nano-LC eq 버 pped quadrupole-time of f1ight mass spectrometer, and the obtained spectra were searched against human protein seq uence data base using MASCOT. Shotgun proteomics allowed a total of 291 human pr。 teins to be confidently assigned . The largest group(17 .2%) of the identified proteins sorted into functional catego ries was included in t he signal t ransduction funct ion except for the hypothetical 0 1' unknown function. This work provides a valuable s ta rting point for the analysis of human salivary proteins and their biological functions and candidates from human whole sali va that may prove to be of diagnostic and therapeutic significance

Human saliva conta ins a la rge number of proteins and peptides whose composition may alter as a conseq uence of disease. '1'0 date‘ however. the proteins and peptides that routinely populate t his oral fluid are largely unknown, '1'0 provid e a ca ta logue 이， sali va protei ns. we have surveyed the unstimulated human whole saliva by using shotgun proteomics. F'or the shotgun a pproach‘ whole sali va proteins were digested into peptides with ChemDigestD and the res ulting pe ptide fragments were sepa rated by RP- HPLC, followed by each fraction was tryptic di gestion ChemDiges tD- Trypsin diges ted pe pt ides were analyzed by tandem mass spectrometry (MS!MS) using a nano-LC equi pped quadru po le-time of fli ght rnass spect rometer, and the obtained spectra were searched against human protein sequence da tabase us ing MASCOT Shotgun proteomics a llowed a total of 291 human proteins to be confidently assigned. The largest gro u p (17 , 2%) of the identifi ed proteins sorted into functional categories was included in the s ignal transducti on function except for the hypothet ical or unknown functio n, This work provides a valuable starting point for the ana lys is of human sa l i va ry protei ns a nd theil‘ biological functions and candidates from human whole saliva that may prove to be of diagn ost ic and t herapeutic s ignif‘ Ica nce