摘要: Gustatory receptors (GRs) are critical for multiple life activities of insects. Owing to the rapid development of genome and transcriptome sequencing, numerous insect GRs have been identified. However, the expression patterns and functions of these receptors are poorly understood. In this study, we analyzed the expression pattern of GRs in Helicoverpa armigera and found that the fructose receptor HarmGR9 was highly expressed in the foregut and abdomen. The function of HarmGR9 was identified using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system. Knockout of the HarmGR9 gene shortened the developmental period of the larval stages and increased food consumption in both larvae and adults. This study revealed the tissue distribution of sugar-sense-related receptors in H. armigera and thereby expanded the understanding of insect feeding regulation.

摘要: Zeugodacus tau (Walker) is an invasive pest. The sterile insect technique is an environment-friendly method for pest control. Understanding the mechanism of sex determination will contribute to improving efficiency of this technique. In this study, we identified the transformer (tra) gene in Z. tau. One female-specific and two male-specific isoforms of tra were found in Z. tau, and the male-specific splicing pattern of tra was found to occur 5 h after egg laying. We performed transcriptome sequencing at 1 h (E1), 5 h (E5), and 9 h (E9) after egg laying and obtained high-quality transcriptome libraries of early embryo development. We identified 13 297 and 11 713 differentially expressed genes (DEGs) from E5 versus E1 and E9 versus E1 comparisons, respectively. To explore the potential functions of the DEGs during embryonic development, Gene Ontology, Clusters of Orthologous Groups of proteins, and Kyoto Encyclopedia of Genes and Genomes analyses were performed. Twenty-six genes potentially involved in sex determination or differentiation, including Maleness-on-the-Y (MoY), were identified in Z. tau. To verify the transcriptome results, 15 genes were selected for quantitative real-time PCR validation. The results were consistent with the transcriptome sequencing results. Moreover, U2 small nuclear riboprotein auxiliary factor (U2AF-50), female lethal d (fl(2)d), and virilizer (vir) were highly expressed at E5, indicating that they may be related to the sex-specific splicing of tra. Further functional analysis is needed to confirm this speculation. Our data provide an insight into the mechanism underlying sex determination and differentiation in tephritid species.

摘要: Ecdysone-induced protein 93F (E93) plays important roles during the metamorphosis process in insects. In this study, a cDNA of the LmE93 gene was identified from the transcriptome of Locusta migratoria, which consists of the 3378-nucleotide open-reading frame (ORF) and encodes 1125 amino acids with helix-turn-helix (HTH) motifs. Reverse transcription quantitative polymerase chain reaction analysis revealed that LmE93 was highest expressed in ovary. The LmE93 expression level was markedly low from the 3rd to 4th instar nymphs, and greatly increased in 1-day-old 5th instar nymphs with a peak on middle nymphal days, then declined in the late nymphal days. Moreover, injected dsLmE93 into 4th and 5th instar nymphs greatly reduced LmE93 transcripts, respectively, and prevented the process of metamorphosis, causing supernumerary nymphal stages. Hematoxylin-eosin staining of the integument showed that the apolysis occurred in advance in 4th instar nymphs, and old cuticle degradation was decreased in dsLmE93-injected locusts of 5th instar nymphs. Smaller and no fully developed wings with reduced columns between the anterior and posterior regions were found in N6 and N7 supernumerary nymphs. In addition, the development of the ovary in dsLmE93-injected locusts was severely blocked, the yolk was almost not formed and there was no development of ovarioles. The results indicated that LmE93 play key roles in the metamorphosis, cuticle, wing and ovarian development of locusts.

摘要: Wolbachia infection is known to affect host reproduction and development. To date, however, the underlying mechanism related to the effects of Wolbachia on host development has not yet been reported. Here, we compared the developmental duration and body weight in different instars of Wolbachia-positive (W+) and Wolbachia-negative (W-) spiders (Hylyphantes graminicola) and detected the relative expression levels of 6 insulin-related genes and 3 ecdysone-related genes using reverse transcription qPCR. Results showed that the developmental duration was significantly shortened in W+ spiders compared with W- spiders. Furthermore, W+ spiders were significantly heavier than W- spiders at the 3(rd) and 4(th) instars, although no significant differences in body weight were observed after maturity. We also found that the expression levels of insulin-like growth factor-2 mRNA-binding protein-1, insulin-degrading enzyme, and ecdysone-inducible protein-1 genes were significantly down-regulated in W+ spiders compared with W- spiders, whereas the expression levels of insulin-like growth factor-binding protein-1, insulin-like peptide receptor, insulin receptor substrate 2-B, insulin-like, ecdysone-induced protein-2, and ecdysone receptor genes were significantly up-regulated in W+ spiders. Our results suggest that Wolbachia may influence host development by affecting insulin and ecdysone signaling pathways.

摘要: Seasonal hibernation has provided an opportunity to study animals' phenotypic plasticity in adaptation to changing environment. In the present study focusing on the female Daurian ground squirrel (Spermophilus dauricus)-a well demonstrated seasonal hibernator-we examined their behavioral, morphological, and metabolic changes during fattening, hibernation, and emergence. Our data indicated high levels of food intake, fat deposition, and body mass increases during fattening compared to hibernation. The levels of serum glucose and triglycerides were also higher during fattening than during hibernation and emergence. Interestingly, although squirrels showed signs of obesity and elevated triglycerides in serum during fattening, triglyceride levels in the liver and skeletal muscles remained unchanged. Our data also indicated that adiponectin levels in serum and cerebrospinal fluid were different between fattening and hibernation. Levels of adiponectin receptor 1 in the skeletal muscle remained low during fattening but peaked in late hibernation. In contrast, adiponectin receptor 2 in the liver showed a steady increase during fattening, which was followed by a significant decrease at early hibernation. Our data indicate that adiponectin may play an important role in preventing heterotopic fat accumulation in a receptor- and organ-specific manner, as well as in facilitating the switch from glucose metabolism to lipid metabolism during fattening and hibernation in female Daurian ground squirrels.