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A full-length complementary (c) DNA encoding ultraviolet ( UV)-sensitive opsin ( sws1) was isolated from the retina of the Japanese sardine Sardinops melanostictus. The sws1 phylogenetic tree showed a sister group relationship with the Cypriniformes, following the ray-finned fish phylogeny. By expressing reconstituted opsin in vitro, it was determined that the maximum absorbance spectrum ( λmax) of sws1 is around 382 nm, being intermediate in position between two subtypes of sws1 pigment that are UV sensitive ( λmax = 355-380 nm) and violet sensitive ( λmax = 388-455 nm), which have been reported to date. The ocular media transmitted >20% transmittance of light in the range of 360-600 nm. In situ hybridization analyses revealed that sws1 messenger (m) RNA is localized in a central single cone surrounded by four double cones in a square mosaic. The square mosaic occupies the ventro-temporal quadrant of the retina and the in situ hybridization signals were dominant in this area suggesting that the fish may use UV vision when looking upward. Based on these results, considerable significances of potential UV sensitivity, in relation to characteristic habits of S. melanostictus, are discussed. [ABSTRACT FROM AUTHOR]

The photoreceptors regulating photoperiodic gonadal development of ayu,Plecoglossus altivelis, are not known. In this study, we examined whether the gonads of ophthalmectomized and pinealectomized (Ex+Px) ayu respond to short photoperiod. Gonadosomatic index (GSI) and plasma levels of sex steroids were significantly increased in Ex+Px ayu kept under short photoperiod in both males and females. On the other hand, there were no significant increase in GSI and sex steroids in Ex+Px ayu kept under long photoperiod. The histological observation of the gonads revealed that oocytes undergoing final maturation in females and proliferation of germ cells in males were observed only in Ex+Px ayu kept under short photoperiod. Altogether, our results strongly suggest unknown photoreceptive organ regulates photoperiodic gonadal development of ayu. [ABSTRACT FROM AUTHOR]

Melanin-concentrating hormone (MCH), melanocyte-stimulating hormone (MSH), and somatolactin (SL) in the hypothalamus-pituitary axis are associated with body color regulation in teleost fish. Although these hormones' production and secretion respond well to light environments, such as background color, little is known about the effects of different water temperatures. We investigated the effects of water temperature, 10°C, 20°C, and 30°C, on body color and the expression of these genes and corresponding receptor genes in goldfish. The body color in white background (WBG) becomes paler at the higher water temperature, although no difference was observed in black background (BBG). Brain mRNA contents of proMCH genes ( pmch1 and pmch2 ) increased at 30°C and 20°C compared to 10°C in WBG, respectively. Apparent effects of background color and temperature on the pituitary mRNA contents of a POMC gene ( pomc ) were not observed. The pituitary mRNA contents of the SLα gene were almost double those on a WBG at any temperature, while those of the SLβ gene ( slb ) at 30°C tended to be higher than those at 10°C and 20°C on WBG and BBG. The scale mRNA contents of the MCH receptor gene ( mchr2 ) in WBG were higher than those in BBG at 30°C. The highest scale mRNA contents of MSH receptor ( mc1r and mc5r ) on BBG were observed at 20°C, while the lowest respective mRNA levels were observed at 30°C on WBG. These results highlight the importance of temperature for the endocrinological regulation of body color, and darker background color may stabilize those endocrine functions.

Introduction: Koi carp, an ornamental fish derived from the common carp Cyprinus carpio (CC), is characterized by beautiful skin color patterns. However, the mechanism that gives rise to the characteristic vivid skin coloration of koi carp has not been clarified. The skin coloration of many teleosts changes in response to differences in the background color. This change in skin coloration is caused by diffusion or aggregation of pigment granules in chromatophores and is regulated mainly by sympathetic nerves and hormones. We hypothesized that there would be some abnormality in the mechanism of skin color regulation in koi carp, which impairs skin color fading in response to background color., Methods: We compared the function of melanin-concentrating hormone (MCH), noradrenaline, and adrenaline in CC and Taisho-Sanshoku (TS), a variety of tri-colored koi., Results and Discussion: In CC acclimated to a white background, the skin color became paler and pigment granules aggregated in melanophores in the scales compared to that in black-acclimated CC. There were no clear differences in skin color or pigment granule aggregation in white- or black-acclimated TS. The expression of mch1 mRNA in the brain was higher in the white-acclimated CC than that in the black-acclimated CC. However, the expression of mch1 mRNA in the brain in the TS did not change in response to the background color. Additionally, plasma MCH levels did not differ between white- and black-acclimated fish in either CC or TS. In vitro experiments showed that noradrenaline induced pigment aggregation in scale melanophores in both CC and TS, whereas adrenaline induced pigment aggregation in the CC but not in the TS. In vitro administration of MCH induced pigment granule aggregation in the CC but not in the TS. However, intraperitoneal injection of MCH resulted in pigment granule aggregation in both CC and TS. Collectively, these results suggest that the weak sensitivity of scale melanophores to MCH and adrenaline might be responsible for the lack of skin color change in response to background color in the TS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Shinohara, Kasagi, Amiya, Hoshino, Ishii, Hyodo, Yamaguchi, Sato, Amano, Takahashi and Mizusawa.)

Organisms have the ability to adapt their behavior and physiology in response to seasonal changes in their habitat's environments. Although it is known that a specific light wavelength affects growth and reproduction in various animal taxa, its effect on sexual and seasonal differences in year-round breeding animals remains unclear. Here, we demonstrate that a blue light stimulus promotes or suppresses larval growth in the red swamp crayfish Procambarus clarkia depending on the season. During the spawning season (natural growing period), blue light irradiation accelerates female growth faster than in males, but suppresses growth in both females and males in the overwintering season. Moreover, these seasonal plastic effects of blue light show apparent sexual differences, with female juveniles exhibiting the greatest sensitivity. Our findings provide an opportunity to research how the red swamp crayfish can adapt to various habitable niches from the point of view of light color perception, and can be applied for the development of a more effective aquaculture system, not only for crayfish, but also for other commercially available decapod crustaceans using a specific light environment.

Background: although high-density lipoprotein has cardioprotective effects, the association between serum high-density lipoprotein cholesterol (HDL-C) and hypertension is poorly understood. Therefore, we investigated whether high and low concentrations of HDL-C are associated with high blood pressure (HBP) using a large healthcare dataset., Methods: in a community-based cross-sectional study of 1,493,152 Japanese people (830,669 men and 662,483 women) aged 40-74 years who underwent a health checkup, blood pressures automatically measured at healthcare center were investigated in nine HDL-C groups (20-110 mg/dL or over)., Results: crude U-shaped relationship were observed between the nine HDL-C and blood pressures in both men and women. Logistic regression analysis showed left-to-right inverted J-shaped relationships between HDL-C and odds ratios for HBP (≥140/90 mmHg and/or pharmacotherapy), with lower limits of 90-99 mg/dL in both sexes, which were unchanged after adjusting for confounding factors. However, further adjustment for body mass index and serum triglyceride concentration revealed positive linear associations between HDL-C and HBP, although blunt U-shaped associations remained in nonalcohol drinkers., Conclusion: both low and extremely high HDL-C concentrations are associated with HBP. The former association might be dependent on excess fat mass concomitant with low HDL-C, whereas the latter association may be largely dependent on frequent alcohol consumption.

Alpha-melanocyte-stimulating hormone (α-MSH), a peptide derived from proopiomelanocortin (POMC), and melanin-concentrating hormone (MCH), act as neuromodulators and regulate food intake in vertebrates. In teleosts, these peptides are also involved competitively in body color regulation; α-MSH induces a dark body color, while MCH induces a pale body color. Similarly, members of the growth hormone (GH) family, somatolactin (SL) and prolactin (PRL), which are involved in the regulation of energy metabolism, are also associated with body color regulation in teleosts. Since these hormones are involved in both body color regulation and energy metabolism, it is possible that feeding status can affect body color. Here, we examined the effects of fasting on the response of goldfish body coloration to changes in background color. Goldfish were acclimated for one week in tanks with a white or black background under conditions of periodic feeding or fasting. The results showed that body color and expression levels of pmch1 and pomc were affected by background color, irrespective of feeding status. Expression levels of sla were higher in fish maintained in tanks with a black background than in tanks with a white background, and higher in the fasted fish compared to the fed fish. However, the pattern of slb expression was almost the opposite of that observed in sla expression. The expression levels of gh and prl in the pituitary, and pmch2a and pmch2b in the brain, were not affected by background color. These results suggest that MCH, α-MSH, SLα, and SLβ might be involved in body color regulation and that they are affected by background color in goldfish. The results also suggest that feeding status may affect body color regulation via SLα and SLβ, although these effects might be limited compared to the effect of background color., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: In healthy people, the lowest daily blood glucose concentration is usually observed in the early morning, after overnight fasting. However, the clinical relevance and the prevalence of fasting biochemical hypoglycemia (FBH) are poorly understood in people who do not have diabetes, although the clinical implications of such hypoglycemia have been extensively studied in patients with diabetes. FBH can be influenced by many factors, including age, sex, body mass, smoking, alcohol drinking, exercise levels, medications, and eating behaviors, such as breakfast skipping and late-night eating., Aim: To determine the prevalence of FBH and investigated its association with potential risk factors in a population without diabetes., Methods: Clinical parameters and lifestyle-related factors were assessed in a cross-sectional study of 695613 people aged 40-74 years who had undergone a health check-up (390282 men and 305331 women). FBH was defined as fasting plasma glucose < 70 mg/dL (3.9 mmol/L) after overnight fasting, regardless of any symptoms. The absence of diabetes was defined as HbA1c < 6.5%, fasting plasma glucose < 126 mg/dL (7.0 mmol/L), and no pharmacotherapy for diabetes. Multivariate logistic regression analysis, with adjustment for confounding factors, was used to identify associations., Results: FBH was present in 1842 participants (0.26%). There were significantly more women in the FBH group (59.1%) than in the non-FBH group (43.9%). Values of most of the clinical parameters, but not age, were significantly lower in the FBH group than in the non-FBH group. Logistic regression analysis showed that a body mass index of ≤ 20.9 kg/m 2 (reference: 21-22.9 kg/m 2 ) and current smoking were significantly associated with FBH, and this was not altered by adjustment for age, sex, and pharmacotherapy for hypertension or dyslipidemia. Female sex was associated with FBH. When the data were analyzed according to sex, men in their 60s or 70s appeared more likely to experience FBH compared with their 40s, whereas men in their 50s and women aged ≥ 50 years appeared less likely to experience FBH. The relationships of FBH with other factors including alcohol drinking and pharmacotherapies for hypertension and dyslipidemia also differed between men and women., Conclusion: FBH occurs even in non-diabetic people, albeit at a very low frequency. FBH is robustly associated with low body mass and smoking, and its relationship with lifestyle factors varies according to sex., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict-of-interest., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)

Background/purpose: With the advancement of an over aging society, the average number of remaining teeth has increased. However, these remaining teeth do not always have sufficient alveolar bone support, and sometimes fabricated connected crowns are applied. This study evaluated the influence of crown material, crown thickness, and alveolar bone resorption on the stress distribution within the abutment teeth of connected crowns., Materials and Methods: Using structural analysis software, a premolar crown model was fabricated. Three kinds of crown materials, two types of crown thickness, two types of post and core systems, and two levels of alveolar bone were assumed and evaluated for the stress distribution within the abutment teeth., Results: The higher material properties crown was, the more stress was concentrated at the marginal area. The composite resin core showed larger stress values around the marginal area, and the metal core showed larger stress values at the tip of the post. Alveolar bone resorption progressed, the marginal area stress value increased., Conclusion: The low elastic modulus crown material polyetheretherketone (PEEK) prevented stress concentrations at the marginal area of the crown and dentine, even with alveolar bone resorption. However, the amount of bone resorption has a great influence on the stress distribution around the tip of the post compared to the type of crown material., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2021 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

We clarified the properties of visual opsin genes in the marbled sole (Pseudopleuronectes yokohamae) by cDNA sequencing, quantification of the opsin gene expression from the larval to the juvenile stage, and measurement of the maximum absorption spectra (λ max ) using photopigment reconstitution. In the marbled sole eye, at least eight visual opsin genes, lws, rh2-a, rh2-b, rh2-c, sws2a, sws2b, sws1, and rh1, were expressed. Quantitative RT-PCR analysis revealed that the expression of opsin genes increased (lws, rh2-c, sws2a, and rh1) or decreased (rh2-a, rh2-b, sws2b, and sws1) from the larval to the juvenile stage. Notably, rh2-a expression was observed only in pre- to mid-metamorphic stage larvae and disappeared after metamorphosis. Thus, pre-metamorphism-specific expression of rh2-a in the marbled sole suggests that its function is restricted to the developmental stage. The reconstituted RH2-A opsin λ max was 470 nm, which is typical of acanthopterygian species. These results strongly suggest that mid-wavelength-sensitive rh2-a expression was diminished drastically in the marbled sole, probably resulting in a shift of spectral sensitivity during its metamorphosis from the larval to the juvenile stage., (Copyright © 2021 Elsevier B.V. All rights reserved.)

A married couple of a 62-year-old woman and a 64-year-old man as well as their neighbor, an 84-year-old woman, visited the hospital complaining of a burning sensation on their hands and feet that had presented on the same day. They had consumed mushrooms that had been picked on a mountain five days before the onset of the symptoms. The symptoms were attributed to Paralepistopsis acromelalga. In conclusion, asking about the dietary history is considered essential when diagnosing the cause of erythromelalgia, which has multiple causative diseases, including food poisoning due to P. acromelalga.

Objectives: Doubt has been cast on the atheroprotective effect of very high high-density lipoprotein cholesterol (HDL-C). Hypertensive retinopathy (HR) is caused by persistent systemic hypertension. Therefore, we aimed to investigate the association between extremely high HDL-C (EH-HDL) and HR., Design: A cross-sectional study., Participants: A total of 4072 general Japanese population aged 40-74 years who underwent regular medical check-ups including fundus examinations., Outcome Measures: HR and clinical parameters including serum HDL-C were investigated. HR was determined by the Keith-Wagener classification and the Scheie classifications for Hypertension and Atherosclerosis (n=4054 available). Serum HDL-C was divided into five categories: 30-49, 50-69, 70-89, 90-109 and ≥110 mg/dL., Results: Overall, 828 (20.3%) subjects had Keith-Wagener-HR, 578 (14.3%) had hypertension-HR, and 628 (15.5%) had atherosclerosis-HR. Blood pressure decreased as HDL-C level increased, whereas the prevalences of HRs showed U-shaped curves against HDL-C with minimum values for HDL-C 90-109 mg/dL. In logistic regression analyses, EH-HDL ≥110 mg/dL was significantly associated with Keith-Wagener-HR and atherosclerosis-HR, compared with HDL-C 90-109 mg/dL after adjustments for age, sex and systolic blood pressure (OR 3.01, 95% CI 1.45 to 6.27 and OR 2.23, 95% CI 1.03 to 4.86). The hypertension-HR was not significantly associated with EH-HDL regardless of adjustment for the confounding factors (p=0.05-0.08). Although serum HDL-C as a continuous variable was inversely associated with three HRs, which disappeared after adjustment for the confounding factors., Conclusion: EH-HDL may be associated with HR independently of blood pressure, suggesting that EH-HDL reflects a special atherosclerotic condition., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Breakfast skipping (BS) has been considered to be associated with obesity, particularly among younger generations. However, few studies have addressed this issue in a middle-aged population considering sex and the conditions prior to breakfast. Therefore, we investigated clinical parameters, self-reported BS, late-night dinner (LND) eating, and late-night snacking (LNS) in ten body mass index (BMI) categories in a cross-sectional study of 892,578 non-diabetic people aged 40-74 years old who underwent a checkup. BS and LND were more prevalent in men (20.7% and 40.5%, respectively) than women (10.9% and 17.4%), whereas LNS was more prevalent in women (15.0%) than men (12.2%; all p < 0.0001). The overall prevalence of BS increased linearly with increasing BMI. However, when subjects were divided into men and women, the prevalence of BS showed a U-shaped relationship with BMI in men (n = 479,203). When male subjects were restricted to those in their 40s or those reporting LND, the prevalence of BS further increased, maintaining a U-shaped form. Logistic regression analysis also showed a U-shaped relationship in the adjusted odds ratios of BMI categories for BS in men and a J-shaped curve in women. In conclusion, our study revealed an unexpectedly high prevalence of BS in middle-aged low-body-weight men.

We investigated the effects of tank brightness on body color, growth, and endocrine systems of rainbow trout (Oncorhynchus mykiss). Five different tank colors that produce varying levels of brightness were used, including black, dark gray [DG], light gray [LG], white, and blue. The fish were reared in these tanks for 59 days under natural photoperiod and water temperature. The body color was affected by tank brightness, such that body color brightness was correlated with tank brightness (white-housed ≥ LG-housed ≥ DG-housed ≥ blue-housed ≥ black-housed). No difference in somatic growth was observed among the fish reared in the five tanks. The mRNA levels of melanin-concentrating hormone (mch1) was higher in white-housed fish than those in the other tanks, and the mRNA levels of proopiomelanocortins (pomc-a and pomc-b) were higher in fish housed in a black tank than those in other tanks. mRNA level of somatolactin, a member of growth hormone family, was higher in black-housed fish than those in white-housed fish. The mRNA levels of mch1 and mch2 in blue-housed fish were similar to those in black-housed fish, while the mRNA levels of pomc-a and pomc-b in blue-housed fish were similar to those in white-housed fish. The current results suggest that tank color is not related to fish growth, therefore any color of conventional rearing tank can be used to grow fish. Moreover, the association between somatolactin with body color changes is suggested in addition to the role of classical MCH and melanophore stimulating hormone derived from POMC., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Trace proteinuria (TrP), which is usually defined as ± by dipstick urinalysis, is considered as normal and of limited clinical significance. However, the relationship between TrP and overt proteinuria (OP) (≥ +1) in the future is unknown. Therefore, we investigated the association between TrP and future incidence of OP in a community-based cohort study., Methods: TrP detected during the initial 2 years, which was classified into transient TrP (once/2 years) (T-TrP) and recurrent TrP (twice/2 years) (R-TrP); and the incidence of OP after 5 years were investigated in 292,257 general Japanese people aged 40 - 68 years who attended checkups. To determine TrP and OP, dipstick urinalysis was conducted with visual reading (VR) by medical staff or automated reading (AR) using a machine reader., Results: Overall, T-TrP and R-TrP were observed in 24,782 (8.5%) and 3,767 (1.3%) subjects, respectively. Both types of TrP were prevalent in the detection with AR than VR. The prevalences of T-TrP and R-TrP showed J-shaped relationships against baseline body mass index (BMI), regardless of sex and BMI categories. The incident of OP after 5 years was larger (around 10%) in R-TrP than T-TrP (around 5%): approximately two times. Logistic regression analysis showed that T-TrP and R-TrP were significantly associated with OP, even after adjustment for relevant confounding factors including age, sex, and BMI (odds ratios (95% confidence intervals (CIs)): 2.77 (2.60 - 2.95) and 4.85 (4.34 - 5.43)), which were not largely altered when sub-analysis was conducted according to men and women, non-obesity and obesity, or AR and VR. In all analysis above, the odds ratios (95% CIs) of R-TrP for OP were higher than T-TrP., Conclusions: Our findings suggest that TrP, particularly R-TrP, is substantially associated with the future incidence of OP, which may be independent of confounding factors and the methods detecting TrP., Competing Interests: None of the authors have any potential conflict of interest., (Copyright 2020, Nakajima et al.)