東京農業大学

BackgroundHepatitis B virus (HBV) infection remains a leading cause of hepatocellular carcinoma (HCC), yet the molecular mechanisms underlying HBV-mediated hepatocarcinogenesis are not fully understood. This study focused on miR-4461, which is encoded within the intronic region of PCBD2 gene, and investigated its role in HBV-derived HCC.MethodsmiR-4461 expression was examined in HBV-expressing hepatoma cell lines and in HBV-infected primary human hepatocytes. Functional analysis evaluated the effects of miR-4461 overexpression or inhibition on hepatocyte proliferation. Candidate targets were screened, and fibrinogen alpha chain (FGA) was tested for regulation by miR-4461. Circulating miR-4461 and plasma FGA were measured in patients with chronic viral hepatitis, including those with HBV-related HCC; in the HBV-HCC cohort, FGA was also assessed before and after surgical tumor resection.ResultsmiR-4461 expression was significantly reduced in HBV-expressing hepatoma cells and HBV-infected primary hepatocytes. Overexpression of miR-4461 inhibited hepatocyte proliferation, whereas its inhibition enhanced proliferation, indicating a tumor-suppressive function. FGA was identified as a downstream target; in hepatoma cells, FGA protein levels were regulated by miR-4461. Clinically, circulating miR-4461 levels were significantly lower in HBV-infected individuals, particularly in those with HBV-related HCC. In contrast, plasma FGA protein levels were markedly elevated in HBV-related HCC and decreased significantly after tumor resection.ConclusionsThese findings suggest a novel regulatory axis in HBV-associated HCC involving HBV-induced suppression of miR-4461 and subsequent upregulation of FGA. Both miR-4461 and FGA were associated with disease status, supporting their potential utility as biomarkers or therapeutic targets in HBV-derived HCC.

The molecular mechanisms underlying odorant reception in insects have been elucidated in the past two decades. Of the odorant receptors (ORs) deorphanized to date, many were primarily derived from lepidopteran, dipteran, and hymenopteran species. However, only a few ORs from coleopteran species have been characterized. Therefore, we aimed to characterize CmacOR13a, a male antenna-dominant OR suggested as a sex pheromone receptor in the cowpea weevil (Callosobruchus maculatus). To this end, we conducted RNAi-based CmacOR13a knockdown and examined its effects on behavioral and electrophysiological responses to sex attractant pheromones. CmacOR13a-silenced males exhibited significantly reduced attraction in the Y-tube olfactometer assay and reduced amplitude of the electroantennogram response to sex attractant pheromones. To our knowledge, this is the second sex attractant pheromone receptor to be characterized in coleopteran beetles. These results provide insights into the molecular mechanisms underlying mating behavior and could facilitate the development of sustainable pest management strategies.

Spatiotemporal analysis of bacterial communities in wastewater can explain the role of bacteria in removing organic matter, phosphorus, and nitrogen as well as the impact of wastewater treatment on riverine ecosystems. This study investigated the bacterial dynamics within an anaerobic-anoxic-oxic (A2O) wastewater treatment plant (WWTP), comprising anaerobic, anoxic, and aerobic tanks, in Tokyo and its impact on the receiving Tama River. 16S rRNA gene analysis and ion chromatography were used to monitor bacterial composition and nutrient concentrations, respectively, to assess the effectiveness of nutrient removal across seasonal temperature variations, and the influence of treated wastewater on riverine bacterial communities. The A2O process effectively removed nutrients, but the nitrification efficiency was affected by temperature, with decreased temperatures correlating with reduced Nitrospira abundance, while nitrate concentrations increased due to higher influent ammonium loads. The WWTP bacterial community exhibited a polarized structure with a dominant core community that was stable over time and across tanks. The abundance of bacterial DNA introduced into the river via treated wastewater decreased downstream, indicating the spatial attenuation of the wastewater treatment impact on the riverine ecosystem. This study demonstrated the temperature sensitivity of WWTP processes, and the transient impact of treated wastewater discharge on river bacterial communities, thereby emphasizing the importance of understanding these dynamics for effective environmental conservation.

The high lactation performance or parity in dairy cows may affect intrauterine oxidative stress (OS) status. This study aimed to investigate the effects of milk yield, blood β-hydroxybutyrate (BHBA) concentrations, and parity on oxidative stress (diacron-reactive oxygen metabolites [d-ROMs]) or antioxidant activity (biological antioxidant potential [BAP]) in the uterine flush fluid of lactating Holstein Friesian dairy cows. Uterine flush fluid samples were collected at 4, 5, 6, and 8 weeks postpartum (n = 43), and d-ROMs and BAP were measured. d-ROMs, BAP, and oxidative stress index (OSI) were investigated in relation to the correlation between milk yield and BHBA concentrations. Cows were classified into primiparous cow groups (P group, n = 11), biparous cow group (B group, n = 5), and the third or more calving groups (M group, n = 27); d-ROMs, BAP, and OSI changes were evaluated across the groups. No significant correlations were noted between milk yield, blood BHBA concentrations, and d-ROMs, BAP, or OSI. The M group exhibited higher d-ROMs and OSI than the P group at 5 weeks, and the M group had a higher OSI than the B group at 6 weeks. Therefore, parity may influence uterine OS and antioxidant activity.

Male sticklebacks (Gasterosteidae) produce an adhesive protein called "spiggin" in the tubular epithelial cells of their kidneys, which they use to attach plants or plant debris together and build nesting sites. Spiggin is a glycoprotein excreted in urine. A similar substance has been reported in freshwater sculpins (Cottidae), and it is thought that male sculpins that nest under stones use this glycoprotein in their enlarged kidneys to attract females to their nests. Based on the phylogenetic closeness of sticklebacks and sculpins and the physiological similarities in their kidneys, we hypothesized that spiggin may play a role in attracting females to nesting sites in sticklebacks. We tested this hypothesis using a Y-maze with the nine-spined stickleback (Pungitius sinensis), a member of the Gasterosteidae. Ovulated females were more consistently attracted to male kidney extracts than female kidney extracts. The high-molecular-weight fraction (molecular weight > 3000) separated from the male kidney extract using a dialysis membrane had an attractive effect on ovulating females, while the low-molecular-weight fraction (molecular weight < 3000) had a repellent effect. The water in the aquarium containing nests built by males significantly attracted ovulating females. These results suggest that spiggin or an unknown component associated with spiggin functions to attract ovulating females. In sticklebacks, which evolved from territorial breeding to building elaborate nests, it is possible that the substance that attracts females produced in the male kidney has evolved into an adhesive component that solidifies the nest.