Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were iden...Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were identified from the Thitarodes xiaojinensis transcriptome. According to their domain structures, six CTLDPs with one carbohydraterecognition domain (CRD) were classified into the CTL-S subfamily. The other 23 CTLDPs with two CRDs were grouped into the immulectin (IML) subfamily. The remaining three with extra regulatory domains were sorted into the CTL-X subfamily. Phylogenetic analysis showed that CTL-S and CTL-X members from different insects could form orthologous groups. In contrast, no T. xiaojinensis IML orthologues were found in other insects. Remarkable lineage-specific expansion in this subfamily was observed reflecting that these CTLDPs, as important receptors, have evolved diversified members in response to a variety of microbes. Prediction of binding ligands revealed that T. xiaojinensis, a coldadapted species, conserved the ability of CRDs to combine with Ca^2+ to keep its receptors from freezing. Comparative analysis of induction of CTLDP genes after different immune challenges indicated that IMLs might play critical roles in immune defenses. This study examined T. xiaojinensis CTLDPs and provides a basis for further studies of their characteristics.展开更多
Ghost moths inhabiting the alpine meadows of the Tibetan Plateau are cold? adapted stenothermal organisms that are susceptible to heat (dead within 7 days at 27 °C exposure). Exploring the metabolic basis of thei...Ghost moths inhabiting the alpine meadows of the Tibetan Plateau are cold? adapted stenothermal organisms that are susceptible to heat (dead within 7 days at 27 °C exposure). Exploring the metabolic basis of their heat susceptibility would extend our understanding of the thermal biology of alpine-dwelling invertebrates. Here, gas chromatography-mass spectrometry-based metabolomics was combined with physiological and transcriptional approaches to determine the metabolic mechanisms of heat susceptibility in Thitarodes xiaojinensis larvae. The metabolomics results showed that 27 °C heat stress impaired the Krebs cycle and lipolysis in T. xiaojinensis larvae, as demonstrated by the accumulation of intermediary metabolites. In addition, carbohydrate reserves were highly and exclusively consumed, and an anaerobic product, lactate, accumulated. This evidence suggested a strong reliance on glycolysis to anaerobically generate energy. The respiration rate and enzymatic activity test results indicated a deficiency in O2 metabolism;in addition, the Krebs cycle capacity was not decreased, and the metabolic flux through aerobic pathways was limited. These findings were further supported by the occurrence of hypoxia symptoms in midgut mitochondria (vacuolation and swelling) and increased transcription of hypoxia-induced factor 1-α.Overall, heat stress caused O2 limitation and depressed the overall intensity of aerobic metabolism in ghost moths, and less efficient anaerobic glycolysis was activated to sustain their energy supply. As carbohydrates were depleted, the energy supply became deficient. Our study presents a comprehensive metabolic explanation for the heat susceptibility of ghost moths and reveals the relationship between O2 metabolism and heat susceptibility in these larvae.展开更多
基金National Key Plan for Scientific Research and Development of China (2017YFD0200400, 2016YFC1200603)National Natural Science Foundation of China (No. 31272366, 30900947, 31672291)Open research Fund Program of State Key Laboratory of Integrated Pest Management (Chinese IPM1505, 1612).
文摘Insects have a large family of C-type lectins involved in cell adhesion, pathogen recognition and activation of immune responses. In this study, 32 transcripts encoding C-type lectin domain proteins (CTLDPs) were identified from the Thitarodes xiaojinensis transcriptome. According to their domain structures, six CTLDPs with one carbohydraterecognition domain (CRD) were classified into the CTL-S subfamily. The other 23 CTLDPs with two CRDs were grouped into the immulectin (IML) subfamily. The remaining three with extra regulatory domains were sorted into the CTL-X subfamily. Phylogenetic analysis showed that CTL-S and CTL-X members from different insects could form orthologous groups. In contrast, no T. xiaojinensis IML orthologues were found in other insects. Remarkable lineage-specific expansion in this subfamily was observed reflecting that these CTLDPs, as important receptors, have evolved diversified members in response to a variety of microbes. Prediction of binding ligands revealed that T. xiaojinensis, a coldadapted species, conserved the ability of CRDs to combine with Ca^2+ to keep its receptors from freezing. Comparative analysis of induction of CTLDP genes after different immune challenges indicated that IMLs might play critical roles in immune defenses. This study examined T. xiaojinensis CTLDPs and provides a basis for further studies of their characteristics.
基金the National Nature Science Foundation of China (31272366, 31772525)the National High Technology Research and Development Program (“863" Program) of China (2011AA10A204)the State Key Laboratory of Integrated Management of Pest Insects and Rodents (Chinese IPM 1504).
文摘Ghost moths inhabiting the alpine meadows of the Tibetan Plateau are cold? adapted stenothermal organisms that are susceptible to heat (dead within 7 days at 27 °C exposure). Exploring the metabolic basis of their heat susceptibility would extend our understanding of the thermal biology of alpine-dwelling invertebrates. Here, gas chromatography-mass spectrometry-based metabolomics was combined with physiological and transcriptional approaches to determine the metabolic mechanisms of heat susceptibility in Thitarodes xiaojinensis larvae. The metabolomics results showed that 27 °C heat stress impaired the Krebs cycle and lipolysis in T. xiaojinensis larvae, as demonstrated by the accumulation of intermediary metabolites. In addition, carbohydrate reserves were highly and exclusively consumed, and an anaerobic product, lactate, accumulated. This evidence suggested a strong reliance on glycolysis to anaerobically generate energy. The respiration rate and enzymatic activity test results indicated a deficiency in O2 metabolism;in addition, the Krebs cycle capacity was not decreased, and the metabolic flux through aerobic pathways was limited. These findings were further supported by the occurrence of hypoxia symptoms in midgut mitochondria (vacuolation and swelling) and increased transcription of hypoxia-induced factor 1-α.Overall, heat stress caused O2 limitation and depressed the overall intensity of aerobic metabolism in ghost moths, and less efficient anaerobic glycolysis was activated to sustain their energy supply. As carbohydrates were depleted, the energy supply became deficient. Our study presents a comprehensive metabolic explanation for the heat susceptibility of ghost moths and reveals the relationship between O2 metabolism and heat susceptibility in these larvae.
