摘要: Spermatogenesis is critical for insect reproduction and the process is regulated by multiple genes. Glycosyltransferases have been shown to participate in the development of Drosophila melanogaster; however, their role in spermatogenesis is still unclear. In this study, we found that alpha 1,4-galactosyltransferase 1 (alpha 4GT1) was expressed at a significantly higher level in the testis than in the ovary of Drosophila. Importantly, the hatching rate was significantly decreased when alpha 4GT1 RNA interference (RNAi) males were crossed with w1118 females, with only a few mature sperm being present in the seminal vesicle of alpha 4GT1 RNAi flies. Immunofluorescence staining further revealed that the individualization complex (IC) in the testes from alpha 4GT1 RNAi flies was scattered and did not move synchronically, compared with the clustered IC observed in the control flies. Terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay showed that apoptosis signals in the sperm bundles of alpha 4GT1 RNAi flies were significantly increased. Moreover, the expression of several individualization-related genes, such as Shrub, Obp44a and Hanabi, was significantly decreased, whereas the expression of several apoptosis-related genes, including Dronc and Drice, was significantly increased in the testes of alpha 4GT1 RNAi flies. Together, these results suggest that alpha 4GT1 may play dual roles in Drosophila spermatogenesis by regulating the sperm individualization process and maintaining the survival of sperm bundles.

摘要: The vast majority of all global species have circadian rhythm cycles that allow them to adapt to natural environments. These regular rhythms are regulated by core clock genes and recent studies have also implicated roles for microRNAs in this regulation. Oviposition is an important circadian behavior in the reproductive cycle of insect vectors of diseases, and little is known about the rhythm or its regulation in mosquitoes. Aedes albopictus is a diurnal mosquito that transmits arboviruses and is the major cause of outbreaks of dengue fever in China. We analyzed the oviposition rhythm patterns of A. albopictus under different light/dark conditions and show that the mosquitoes have an oviposition peak between zeitgeber time 9 (ZT 9) and ZT 12. Furthermore, the antagomir-mediated knockdown of expression of the microRNA miR-2940-1 affected the oviposition rhythm of A. albopictus. These data support the conclusion that miR-2940-1 is involved in the regulation of oviposition rhythm in A. albopictus and provide a foundation for using oviposition rhythms as a new target for vector mosquito control.

摘要: The role of miRNAs in the regulation of seasonal reproduction in rodents, particularly in relation to photoperiod changes, is still poorly understood. Previous studies on miRNA transcriptomes of striped hamster (Cricetulus barabensis) testes have indicated that the photoperiodism of testes, especially apoptosis, may be influenced by miRNAs. As a functional miRNA, cba-miR-222-3p in striped hamster testes exhibits suppression under a short photoperiod. To elucidate the potential role of testicular cba-miR-222-3p in the seasonal reproduction of striped hamsters, we exposed male striped hamsters to different photoperiods or injected miRNA agomir into the testes and observed the effects of these treatments, particularly some indicators related to apoptosis. The results showed that the levels of apoptosis in the testes increased in short daylength, accompanied by a significant decrease in cba-miR-222-3p expression and an increase in TRAF7 expression. Dual luciferase reporter assays verified the targeting relationship between cba-miR-222-3p and TRAF7 predicted by bioinformatics. In addition, the expression of TRAF7 decreased in the testes, which injected miRNA agomir, leading to inhibition of apoptosis, and the expression of key genes (MEKK3, p38, p53) in the downstream MAPK signaling pathway of TRAF7 was suppressed. These results suggest that short daylength induces testicular apoptosis in striped hamsters, and one possible mechanism is that the decreased expression of miR-222-3p in testes reduces the repression of TRAF7 translation, thereby activating the MAPK pathway and affecting the level of testicular apoptosis. These findings reveal the potential role of miR-222-3p in animal reproduction and provide new insights into the regulation of rodent populations.

摘要: Diapause is an adaptive strategy employed by insects to endure adverse environmental conditions and is characterized by reduced metabolic activity, primarily due to a decreased respiratory rate. AMP-activated protein kinase (AMPK) serves as an intracellular energy regulator, modulating energy metabolism in response to metabolic fluctuations. However, its role in pupal diapause of the cotton bollworm, Helicoverpa armigera, remains unclear. In this study, we found that AMPK and its active form, P-AMPK, are highly expressed in diapause-destined pupae. Furthermore, activation of AMPK delayed the development of nondiapause-destined pupae, suggesting a critical role for AMPK in the regulation of pupal diapause in H. armigera. Manipulating AMPK activity in H. armigera epidermal (HaEpi) cells and pupae significantly influenced the expression of hypoxia-inducible factor-1 alpha (HIF-1 alpha), which our laboratory previously reported as a key inducer of pupal diapause through the reduction of mitochondrial activity in H. armigera. Histone deacetylase 4 (HDAC4), a shuttle protein phosphorylated by AMPK which translocates between the cytoplasm and the nucleus, was found to exhibit significantly higher expression in diapause-destined pupal brains compared to their nondiapause counterparts. AMPK in both HaEpi cells and pupae positively regulated the protein levels of P-HDAC4 by binding to the HDAC4 promoter. Additionally, HDAC4 was shown to enhance HIF-1 alpha expression in diapause-destined individuals. HDAC4 binds to and deacetylates heat shock protein 70 (HSP70), and reduced acetylation of HSP70 was found to significantly elevate HIF-1 alpha protein levels. The AMPK-HIF-1 alpha signaling pathway appears to play a pivotal role in reducing mitochondrial activity and facilitating diapause induction in H. armigera pupae.

摘要: The Gansu zokor (Eospalax cansus), a subterranean rodent endemic to the Loess Plateau of China, exhibits remarkable adaptability to hypoxic environments. While gut microbiota are known to regulate lipid metabolism through bile acid (BA) pathways, this phenomenon has not been investigated in subterranean rodents exposed to hypoxia. This study employed 16SrRNA sequencing, targeted analysis of BA metabolites in colonic contents, and assessments of BA and lipid metabolites alongside molecular analyses in the liver and ileum under conditions of acute and chronic hypoxia in Gansu zokors. The results revealed that hypoxia altered the composition of gut microbiota and BA pools in Gansu zokors. Hypoxia-induced changes increased the abundance of gut microbiota associated with BA metabolism, thereby modulating lipid metabolism via farnesoid X receptor (FXR) signaling in the distal ileum and liver cells. Under acute hypoxia, FXR upregulated lipid synthesis and suppressed fatty acid beta-oxidation by downregulating the carnitine palmitoyl-transferase1A (CPT1A) expression. Conversely, during chronic hypoxia, particularly under long-term exposure, FXR reduced lipid synthesis and enhanced fatty acid beta-oxidation by upregulating acyl-CoA oxidase (ACOX1) expression. In both hypoxic conditions, FXR facilitated lipoprotein metabolism. In summary, this study elucidates that gut microbiota-mediated BA metabolic pathways contribute to the Gansu zokor's ability to maintain lipid metabolic homeostasis and adaptation to hypoxia.