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.

Helicobacter pylori are known as a causative agent of gastritis, gastric duodenum and peptic ulcer, and gastric cancer, and multiple drug use is associated with various side effects in patients. The discovery of antibacterial substances against H. pylori from Korean resource plants is an important substitute for antibiotics. 52 species of Korean resource plants were collected and extracted with 50% ethanol, and antibacterial activity against H. pylori was measured using the disk diffusion method. The toxicity of plant extracts to human gastric adenocarcinoma(AGS) cells was measured by MTT assay, and the level of IL-8 secreted when gastric epithelial cells were inoculated with H. pylori was measured. As a result of measuring the antibacterial activity of H. pylori, antibacterial activity was confirmed in 38 plant extracts. The plant species with the strongest antibacterial activity were Chrysanthemum indicum, Rheum rhabarbarum, Patrinia scabiosaefolia and Petasites japonicus. C. indicum was not cytotoxic to H. pyroli-infected AGS cells and showed anti-inflammatory effects. This study's results can be used to develop healthy, functional foods and medical materials.

The salivary glands of hard ticks consist of three types (type I, II, and III) of acini according to their functions and location. The type II and III acini play critical roles in tick salivation, which is likely controlled by a variety of neuropeptides or neurotransmitter via interaction with their receptor, G protein-coupled receptors (GPCRs). Orchestration of dopamine receptor (D1) and invertebrate specific D1-like dopamine receptor (InvD1L) located in type II and III acini precisely control tick salivary secretion via collection of primary saliva in the lumen and expulsion of collected saliva, respectively. The two dopamine receptors (D1 and InvD1L) in Haemaphysalis longicornis were identified as 1278 bp (426 aa) and 1362 bp (454 aa) in length, respectively. Both dopamine receptors were functionally analyzed through Ca2+ and cAMP assay using the heterologous expression system. The transcripts of D1 and InvD1L were profiled from synganglion and salivary glands of female ticks (unfed, 3/18/60/96 post blood meal and replete). D1 and InvD1L were significantly upregulated in the early phase of blood feeding from female H. longicornis. Salivary secretion induced by dopamine was significantly reduced by RNAi of D1 and InvD1L. Interestingly, RNAi of two dopamine receptors induced a significantly longer period of blood feeding in female ticks, which were significantly lighter after feeding than control. Taken together, it was suggested that D1 and InvD1L play critical roles in early and late phase of tick blood feeding for feeding capability.

Receptor tyrosine kinase c-Kit, a marker found on interstitial cells of Cajal (ICCs), is expressed in Leydig cells, which are testicular interstitial cells. The expression of other ICC markers has not yet been reported. In this study, we investigated the expression of c-Kit and anoctamin 1 (ANO1), another ICC marker, in mouse testes. In addition, the relationship between c-Kit and ANO1 expression and Leydig cell function was investigated. We observed that c-Kit and ANO1 were predominantly expressed in mouse Leydig cells. The mRNA and protein of c-Kit and ANO1 were expressed in TM3, a mouse Leydig cell line. LH induced an increase in intracellular Ca2+ concentration, membrane depolarization, and testosterone secretion, whereas these signals were inhibited in the presence of c-Kit and ANO1 inhibitors. These results show that c-Kit and ANO1 are expressed in Leydig cells and are involved in testosterone secretion. Our findings suggest that Leydig cells may act as ICCs in testosterone secretion.

The salivary glands secrete saliva, which plays a role in the maintenance of a healthy oral environment. Under physiological conditions, saliva secretion within the acinar cells of the gland is regulated by stimulation of specific calcium (Ca2+) signaling mechanisms such as increases in the intracellular Ca2+ concentration ([Ca2+]i) via storeoperated Ca2+ entry, which involves components such as Orai1, transient receptor potential (TRP) canonical 1, stromal interaction molecules, and inositol 1,4,5-triphosphate (IP3) receptors (IP3Rs). Homer proteins are scaffold proteins that bind to G protein-coupled receptors, IP3Rs, ryanodine receptors, and TRP channels. However, their exact role in Ca2+ signaling in the salivary glands remains unknown. In the present study, we investigated the role of Homer2 in Ca2+ signaling and saliva secretion in parotid gland acinar cells under physiological conditions. Deletion of Homer2 (Homer2−/−) markedly decreased the amplitude of [Ca2+]i oscillations via the stimulation of carbachol, which is physiologically concentrated in parotid acinar cells, whereas the frequency of [Ca2+]i oscillations showed no difference between wild-type and Homer2−/− mice. Homer2−/− mice also showed a significant decrease in amylase release by carbachol in the parotid gland in a dose-dependent manner. These results suggest that Homer2 plays a critical role in maintaining [Ca2+]i concentration and secretion of saliva in mouse parotid gland acinar cells.

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.

The purpose of the present study was to determine the elaborate characteristics of ovarian changes including follicles and corpus luteum, and hormonal patterns of gonadotropin surge mode secretions during the normal consecutive estrous cycle in three dairy cows. Non-lactating and multiparous Holstein cows (n=3) used as experimental animals. The cows were assigned to examine the relationship among ovarian changes (follicle, corpus luteum), ovarian steroids (estradiol, progesterone) and gonadotropin (LH, FSH) surge mode secretion during the successive estrous cycles by rectal palpation, ultrasonography and hormonal assay. The mean length of the estrous cycle for the three cows was 23.1 ± 1.44 days (± SEM), with a range of 20-28 days. In six estrous cycles, the number of two follicular waves, three follicular waves and four follicular waves was 2, 3 and 1, respectively. The sequential ultrasonographic monitoring showed that the corpus luteum with ≥ 10 mm in diameter detected from Day 2 (Day 0 is ovulation) in six estrous cycles of all cows. Preovulatory increases in estradiol concentration reached 10.36 ± 1.10 pg/ml on the 2 days before ovulation of the last dominant follicle. All cows exhibited a preovulatory rise in estradiol concentration followed by a typical preovulatory LH and FSH surge. The mean interval from the peak of LH/FSH surge to ovulation of the last dominant follicle was 31.3 ± 1.76 h (± SEM). In these results, each dairy cow showed that ovarian morphological changes and gonadotropin surge mode secretion will be regulated by various environmental factors including age, breeds, nutrition, breeding conditions, etc.

In the present study, we investigated the physiological effects of smartphone use at night when the display luminance and white balance were differently manipulated. Two levels of luminance and two types of white balance were combined to form four types of displays. Subjects were instructed to use smartphones between 23:00 to 01:00 twice a week for two weeks, and for each trial, subjects were given one of the four display types. Melatonin concentration in the saliva, body temperature and heart rate were measured before and after each experiment. The experimental result showed that the low luminance display supported melatonin secretion and thermoregulation compared to the high luminance display. With regard to the white balance, higher melatonin level was observed when using the display that filtered blue light. The low luminance display together with yellowish tint best supported restful sleep at night in terms of every physiological response. This study collectively demonstrates that bright and blue light emitted from smartphone displays adversely affect melatonin secretion, body temperature, and heart rate, and therefore, suggests the use of a display with low luminance or a display that filters blue light for a restful sleep at night.

The Osmia cornifrons plays an important role in pollinating fruit trees, such as apple trees. To better understand diapause and oviposition in O. cornifrons, we investigated the correlation between the ovarian development and secretion level of OcVg protein in hemolymph. During ovarian development in wintering the number of oocytes progressively increased in comparison with the length of the ovaries and the oocytes. After emergence, the oocyte and ovary sizes developed until 6 days after emergence and declined after 6 days, but the number of oocytes decreased gradually. The secretion level of OcVg protein in hemolymph revealed that during wintering, the secretion level increased from 1 month to 2 months and then stagnated after 2 months. After diapause, the secretion level increased gradually until day 6 of the newly emerged adult from cocoon stage, and thereafter gradually declined, remaining detectable until day 30 of the adult stage. The correction analysis between ovarian development and OcVg secretion level in hemolymph found that in wintering, the number of oocytes was positively correlated to OcVg secretion level. After diapause, the ovary and first oocyte lengths and the number of oocytes showed significant changes in OcVg secretion level and positively correlated with OcVg secretion level, respectively. These results suggest that there is a significant interaction between ovarian development and the secretion level of OcVg protein and the pattern of ovarian development and secretion of OcVg protein are stage-specific in the O. cornifrons female.

최근 알로에 베라 섭취에 의한 독성 간염이 보고되고 있으나, 아직까지 알로에 베라의 간에 대한 염증 효과가 명확히 밝혀지지 않았다. 본 연구는 알로에 베라 에탄올 추출물이 간세포의 염증 발현에 미치는 영향과 그 기전을 밝히기 위해 수행되었다. 0.001~100 μg/mL의 알로에 베라 추출물을 HepG2세포에 처리하여 MTT assay를 시행한 결과, 모든 농도에서 세포사멸이 유도되지 않았다. 그러나 모든 농도에서 알로에 베라 추출물은 염증성 사이토카인인 IL-8의 분비를 15.7~25.8%까지 유의적으로 증가시켰다(p<0.05). 또 다른 사이토카인인 M-CSF도 알로에 베라 추출물에 의해 36.3~61.5%까지 유의적으로 분비가 증가되었다(p<0.05). 본 연구 결과는 알로에 베라 추출물이 IL-8과 M-CSF와 같은 염증성 사이토카인 분비기전에 의해 간에 염증을 유발할 수 있음을 보여준다. 또한 알로에 추출물에 의해 유발될 수 있는 간염기전을 제시함으로써, 향후 수행될 추가 실험을 위한 기초 자료로 그 가치가 높을 것으로 사료된다.

About 70% of total honey products produced by Korean bee keepers was acacia honey. The remaining 30% was chestnut honey, jujube honey, snowbell honey, and another honey. False acacia, went down in payability since the middle 2000s because of simultaneous blooming etiolation chlorsis decreases productivity after aging. Therefore, substitution honey plants were necessary. This study estimated nectar secretion amount of each flower and productivity per ha at 14 medical herbs. Each flower, Codonopsis lanceloata, estimated a majority nectar secretion amount at 176.08 ul for each of the 14 medical herbs. Astragalus membranaceus estimated majority nectar secretion amount at 1273.3 L per ha for each of the 14 medical herbs. Medical herbs were hypothesized with valuable honey plants.

Jujube trees, herbal medicine material, produce not only their fruit but also jujube honey for bee and human’ food sources. Although jujube is an important honey plant after acacia bloom, the research was done with 15-year-old jujube trees grown in ChungDo-Gun, which there was no information on jujube floral nectar. According to the research, jujube nectar secretion mostly happens during dawn and morning for two days. The average number of inflorescence per tree is 638.1 according to the research. And also, the average number of flowers per inflorescence is 64.4. The amount of nectar secretion is 11.6 ul on average per flower, and hypothesized nectar secretion from 15-year-old tree per tree is 476.682 ul. Also,a jujube tree has 545.5ul hypothesized nectar secretion per ha by the research.

In ruminants, Interferon-τ (IFN-τ) has the role of recognizing pregnancy signals produced by the embryo and it may have an important role during the luteolysis. Therefore, the purpose of the present study was to investigate the effect of IFN-τ on prostaglandin synthesis, cyclooxygenase-2 (COX-2) gene expression in vitro and secretion of progesterone (P4) in vivo. The epithelial and stromal cells isolated from bovine endometrium were cultured with different doses of IFN-τ (0, 0.02, 0.2 and 2 μg/ml). Human chorionic gonadotropin (hCG, 1.5 IU/ml) was used as a positive control. Prostaglandin E2 and F2α levels in the culture media were analyzed by enzyme immunoassays, and total RNA was extracted from the cells for RT-PCR. P4 concentrations in blood samples were assayed by chemiluminescent immunoassay system. In epithelial cells, COX-2 gene expression was increased in the presence of IFN-τ (p<0.05), but it was not significantly different in all groups of stromal cells except 2 μg/ml IFN-τ group (p<0.05). Although IFN-τ did not affect PGE2 and PGF2α production in epithelial cells, it decreased PGE2 and PGF2α production significantly in stromal cells (p<0.05). In vivo experiment, the P4 concentrations in blood sample was significantly increased after injection of 1 μg/ml IFN-τ. These results indicate that PG production was mediated by COX-2 expression in the stromal cells but it did not affect in the epithelial cells, and suggest that treatment of IFN-τ was to improve the implantation environment of uterine by maintenance of high P4 concentration. * This work was carried out with the support of “Cooperative Research Program for Agriculture Science & Technology Development (Project No. PJ907008)” Rural Development Administration, Republic of Korea.

The effects of β-lapachone on gastric secretion were investigated. The pylorus of male Sprague-Dawley rats was ligated and intraduodenally injected with β-lapachone, and the volume, pH, free HCl, and total acidity of gastric fluid were measured 6 hours after the operation. Treatment with β-lapachone resulted in dose-dependent inhibition of gastric secretion Gastric fluid was reduced to 42.9% of control level by 100 mg/kg of β-lapachone, leading to an increase of pH to 6.70 from 1.85 in the control group. In parallel with the increase of pH, at this dosage, free HCl and total acidity decreased to 16.7% and 12.0%, respectively, of control levels. β-Lapachone exhibited ED50 values of 72, 46, and 47 mg/kg for inhibition of gastric volume, free HCl, and total acidity, respectively, implying a superior efficacy on gastric acid to volume. In comparison, pantoprazole (30 mg/kg) reduced the volume, free HCl and total acidity of gastric fluid to 53.0%, 26.0%, and 25.0%, respectively, of control levels, resulting in an increase in pH to 6.36. In the current study, it was confirmed that β-lapachone at an appropriate dose (100 mg/kg) exerted a higher inhibitory effect on gastric secretion than pantoprazole (30 mg/kg), a well-known proton-pump inhibitor. Therefore, it is suggested that β-lapachone could be a candidate compound for prevention or treatment of gastric ulcers induced by diverse psychological and physical stimuli.

Male adults of bean bug, Riptortus clavatus Thunberg (Heteroptera: Alydidae), release aggregation pheromone (AP) which consists of (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and tetradecyl isobutyrate (TI). Variation in the pheromonal secretion were checked by the factors of age, mating status, seasons, body weight and time in a day. There were no significant differences in the amounts of AP secretion by mating, body weight, and time in a day. Higher amount of AP was detected from older males than younger ones. The amount of AP detected was higher in the males collected from April to September than in those collected during October. No AP was detected in the males of November and December. These phenomena in the AP secretion were discussed in relation to food exploitation and reproductive diapause of the bean bug.

The objective of present study was to investigate the effect of seasons on reproductive performance of Hanwoo and Holstein heifers. Heat stress in summer or cold stress in winter stress to Hanwoo and Holstein heifers may bring reproduction failure, which would pose an important economic loss, even around Daegwallyeong region located in high mountainous area. Seasonal differences in the serum levels of LH, FSH and progesterone () in response to environmental factors (hot and cold) out of 20 pubertal Hanwoo heifers in Daegwallyeong, Gangwon Province and 20 non-lactating Holstein heifers in Chonan city of Republic of Korea at 2-3 years of age were compared. Blood samples for hormonal analysis were from jugular vein after detection of estrus repeatedly over four seasons within four-week intervals (Spring: May to June, Summer: July to August, Autumn: October to November and Winter: January to February). In Hanwoo heifer population, averages of LH and FSH concentration in spring and in summer were greater compared to those in winter (p<0.05). LH or FSH levels tended to be greater (p=0.06) in spring and less (p=0.09) in winter compared to the levels in autumn. Only in summer, cattle seemed to show lower LH or FSH secretion (p<0.05). Similar to the results in Hanwoo heifers, the serum concentrations of LH and FSH in Holstein heifers decreased further by heat stress in summer when P 4 levels were high during luteal phase. The results demonstrate significant effect of summer heat on reproduction of Hanwoo or Holstein heifers. Although parameters indicating the extent of heat stress were not measured in this study, we suggest that serum hormone levels could be considered as successful indicators of summer heat stress condition for Hanwoo and Holstein heifers even under rather cool summer climate.