Insects occupy a broad range of habitats after terrestrialization and radiation from marine crustaceans 519 million years ago(Schwentner et al.,2017).They found themselves in a new environment,foremost jeopardizing th...Insects occupy a broad range of habitats after terrestrialization and radiation from marine crustaceans 519 million years ago(Schwentner et al.,2017).They found themselves in a new environment,foremost jeopardizing them with low humidity,i.e.,dry or desiccation conditions.In addition,their co-evolution with land plants both as beneficial and maleficial companions exposed them to plant-produced xenobiotics(secondary metabolites)that as the plant defence molecules may have potential adverse effects on insects.Insects learned to cope with both situations,among others,through the evolution and activation of H-type ATP-binding cassette(ABC)transporters(Fig.1).Indeed,ABCH transporters are arthropod-specific ABC transporters that,in all kingdoms of living organisms,using ATP hydrolysis,transport molecules from one side of a membrane to the other,thereby influencing the physiological milieus of both compartments.展开更多
Wings are essential for insect fitness.A number of proteins and enzymes have been identified to be involved in wing terminal differentiation,which is characterized by the formation of the wing cuticle.Here,we addresse...Wings are essential for insect fitness.A number of proteins and enzymes have been identified to be involved in wing terminal differentiation,which is characterized by the formation of the wing cuticle.Here,we addressed the question whether chitinase 10(Cht10)may play an important role in chitin organization in the wings of the fruit fly Drosophila melanogaster.Initially,we first found that Cht10 expression coincides with the expression of the chitin synthase coding gene kkv.This suggests that the respective proteins may cooperate during wing differentiation.In tissue-specific RNA interference experiments,we demonstrate that suppression of Cht10 causes an excess in chitin amounts in the wing cuticle.Chitin organization is severely disrupted in these wings.Based on these data,we hypothesize that Cht10 restricts chitin amounts produced by Kkv in order to ensure normal chitin organization and wing cuticle formation.In addition,we found by scanning electron microscopy that Cht10 suppression also affects the cuticle surface.In turn,cuticle inward permeability is enhanced in Cht10 Aess wings.Moreover,flies with reduced Cht 10 function are unable to fly.In conclusion,Cht10 is essential for wing terminal differentiation and function.展开更多
Many holo-and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle(SC).To date,scholarly understanding of the SC composition and SC-related gene functions has been limited,e...Many holo-and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle(SC).To date,scholarly understanding of the SC composition and SC-related gene functions has been limited,especially for hemimetabolous insects.In this study,we initially performed transmission electron microscopic(TEM)observation and chitin staining of the SC in Nilaparvata lugens,a hemimetabolous rice pest known as the brown planthopper(BPH).We confirmed that the SC was a chitin-rich lamellar structure deposited gradually during the early embryogenesis.Parental RNA interference(RNAi)against Nilaparvata lugens chitin synthase 1(NlCHS1)in newly emerged and matured females resulted in decreases of egg hatchability by 100%and 76%,respectively.Ultrastructural analyses revealed loss of the lamellar structure of the SC in dsNlCHS1-treated eggs.According to temporal expression profiles,five cuticle protein coding genes,NlugCpr1/2/3/8/90,were specifically or highly expressed during the SC formation period,and NlugCpr1/2/3/90 were further detected in 72 h eggshells extract by ultra-performance liquid chromatography-tandem mass spectrometry/mass spectrometry.NlugCpr2/3/90 were likely three SC-specific cuticle proteins.TEM observations of the SC following parental RNAi against NlugCpr1/2/3/8/90 demonstrated that NlugCpr3/8/90 were essential for SC formation.The study provided an understanding of the SC formation process and SC-related cuticle proteins in BPHs,which offer potential targets for pest control in the egg stage as well.展开更多
Bioinsecticides are naturally-occurring substances from different sources that control insect pests.Ideal bioinsecticides should have low toxicity to non-target organisms.They should also be easily degraded in sewage ...Bioinsecticides are naturally-occurring substances from different sources that control insect pests.Ideal bioinsecticides should have low toxicity to non-target organisms.They should also be easily degraded in sewage treatment works and natural environments,highly effective in small quantities and affect target pests only.Public concerns about possible side-effects of synthetic pesticides have accelerated bioinsecticide research and development.However,to develop bioinsecticides into mainstream products,their high production costs,short shelf-life and often uncertain modes of action need to be considered.This review summarizes current progress on bioinsecticides which are categorized as biochemical insecticides and their derivatives,plant-incorporated protectants,and microbial bioinsecticides.The current constraints that prevent bioinsecticides from being widely used are discussed and future research directions are proposed.展开更多
Lipid homeostasis is crucial for growth and development of organisms.Several cytochrome P450 monooxygenases(CYPs)are involved in lipid metabolism.The function of Cyp3llal in the anterior midgut as a regulator of phosp...Lipid homeostasis is crucial for growth and development of organisms.Several cytochrome P450 monooxygenases(CYPs)are involved in lipid metabolism.The function of Cyp3llal in the anterior midgut as a regulator of phosphatidylethanolamine(PE)metabolism in Drosophila melanogaster has been demonstrated,as depletion of Cyp31lal caused larval growth arrest that was partially rescued by supplying PE.In this study,we investigated the role of CYP311A1 in wing morphogenesis in Drosophila.Using the GAL4-UAS system,Cyp31lal was selectively knocked down in the wing disc.A deformed wing phenotype was observed in flies with reduced Cyp31lal transcripts.BODIPY and oil red O staining revealed a reduction of neutral lipids in the wing disc after the depletion of Cyp31lal.In addition,we observed an enhanced sensitivity to Eosin Y penetration in the wings of Cyp31lal knocked-down flies.Moreover,the reduction of CYP311A1 function in developing wings does not affect cell proliferation and apoptosis,but entails disordered Phalloidin or Cadherin distribution,suggesting an abnormal cell morphology and cell cortex structure in wing epithelial cells.Taken together,our results suggest that Cyp3llal is needed for wing morphogenesis by participating in lipid assembly and cell homeostasis.展开更多
Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of experiments.The Gal4/UAS system has been widely used to direct gene expression for studying complex genetic...Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of experiments.The Gal4/UAS system has been widely used to direct gene expression for studying complex genetic and biological problems in Drosophila melanogaster and other model organisms.Driven by a given tissue-specific Gal4,expressing UAS-transgene or UAS-RNAi(RNA interference)could be used to up-or down-regulate target gene expression,respectively.However,the efficiency of the Gal4/UAS system is roughly predefined by properties of transposon vector constructs and the insertion site in the transgenic stock.Here,we describe a simple way to modulate optomotor blind(omb)expression levels in its endogenous expression region of the wing disc.We co-expressed UAS-omb and UAS-omb-RNAi together under the control of dpp-Gal4 driver which is expressed in the omb expression region of the wing pouch.The repression effect is more sensitive to temperature than that of overexpression.At low temperature,overexpression plays a dominant role but the efficiency is attenuated by UAS-omb-RNAi.In contrast,at high temperature RNAi predominates in gene expression regulation.By this strategy,we could manipulate omb expression levels at a moderate level.It allows us to manipulate omb expression levels in the same tissue between overexpression and repression at different stages by temperature control.展开更多
Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular int...Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular intima of the foregut and hindgut are unclear.Here,we investigated the roles of their respective genes LmCDAI and Lm-CD42 in this process,in the hemimetabolous insect Locusta migratoria.Transcripts of LmCDAI and LmCDA2 were highly expressed both before and after molting in the foregut.In the hindgut,their expression was high only before molting.In both the foregut and hindgut,LmCDA1 protein was localized in the basal half of the chitin matrix(procuti-cle),whereas LmCDA2 was detected in the upper half of the procuticle.K nockdown of LmCDAI by RNA interference(RNAi)in 5th-instar nymphs caused no visible defcts of the hindgut cuticle.By contrast,the chitinous lamellae of the cuticular intima in the foregut of knockdown animals were less compact than in control animals.RNAi against LmCDA2 led to thickening of both the foregut and hindgut cuticles,with a greater number of thinner laminae than in the respective control cuticles.Taken together,our results show that LmCDAI and LmCDA2 have distinct,but overlapping,functions in chitin organization in the foregut cuticle.However,in the hindgut,this process seems independent of LmCDA1 activity but requires LmCDA2 function.Thus,the CDAs reflect tissue-specific differences in cuticular organization and function,which need further detailed molecular and histological analyses for full comprehension.展开更多
Dear Editor,The insect cuticle is a multifunctional coat that defines and stabilizes the shape of the body,appendages and internal organs,serves as a barrier against water and chemical compounds,such as insecticides,p...Dear Editor,The insect cuticle is a multifunctional coat that defines and stabilizes the shape of the body,appendages and internal organs,serves as a barrier against water and chemical compounds,such as insecticides,prevents infection and protects against predators(Moussian,2010).The surface of insects is covered by a lipid layer composed of diverse hydrocarbons,wax esters,fatty acids,fatty alcohols,sterols and triglycerides.Delivery of lipids to the body surface occurs through the cuticle by a nano-canal system consisting of pore canals(PC)and wax canals(WC).展开更多
The polysaccharide chitin is a major scaffolding molecule in the insect cuticle.In order to be functional,both chitin amounts and chitin organization have been shown to be important parameters.Despite great advances i...The polysaccharide chitin is a major scaffolding molecule in the insect cuticle.In order to be functional,both chitin amounts and chitin organization have been shown to be important parameters.Despite great advances in the past decade,the molecular mechanisms of chitin synthesis and organization are not fully understood.Here,we have characterized the function of the Chitinase 6(Cht6)in the formation of the wing,which is a simple flat cuticle organ,in the fruit fly Drosophila melanogaster.Reduction of Cht6 function by RNA interference during wing development does not affect chitin organization,but entails a thinner cuticle suggesting reduced chitin amounts.This phenotype is opposed to the one reported recently to be caused by reduction of Cht10 expression.Probably as a consequence,cuticle permeability to xenobiotics is enhanced in Cht6-less wings.We also observed massive deformation of these wings.In addition,the shape of the abdomen is markedly changed upon abdominal suppression of Cht6.Finally,we found that suppression of Cht6 transcript levels influences the expression of genes coding for enzymes of the chitin biosynthesis pathway.This finding indicates that wing epidermal cells respond to activity changes of Cht6 probably trying to adjust chitin amounts.Together,in a working model,we propose that Cht6-introduced modifications of chitin are needed for chitin synthesis to proceed correctly.Cuticle thickness,according to our hypothesis,is in turn required for correct organ or body part shape.The molecular mechanisms of this processes shall be characterized in the future.展开更多
Chitin is the second most abundant polysaccharide on earth. It is produced at the apical side of epidermal, tracheal, fore-, and hindgut epithelial cells in insects as a central component of the protective and support...Chitin is the second most abundant polysaccharide on earth. It is produced at the apical side of epidermal, tracheal, fore-, and hindgut epithelial cells in insects as a central component of the protective and supporting extracellular cuticle. Chitin is also an important constituent of the midgut peritrophic matrix that encases the food supporting its digestion and protects the epithelium against invasion by possibly ingested pathogens. The enzyme producing chitin is a glycosyltransferase that resides in the apical plasma membrane forming a pore to extrude the chains of chitin into the extracellular space. The apical plasma membrane is not only a platform for chitin synthases but, probably through its shape and equipment with distinct factors, also plays an important role in orienting and organizing chitin fibers. Here, I review findings on the cellular and molecular constitution of the apical plasma membrane of chitin-producing epithelia mainly focusing on work done in the fruit fly Drosophila melanogaster.展开更多
With climate change,the spotted-wing Drosophila(SWD,Drosophila suzukii)invades a great number of fruit production regions worldwide.A plethora of insecticides are being applied for management of this pest.As expected,...With climate change,the spotted-wing Drosophila(SWD,Drosophila suzukii)invades a great number of fruit production regions worldwide.A plethora of insecticides are being applied for management of this pest.As expected,SWD develops resistance against some potent insecticides or is rather insensitive to some others.Therefore,there is an urgent need to identify and characterize alternative insecticides to control SWD populations.Here,we have studied the effects of the orally applied inhibitor of the fatty acid synthesis pathway spirotetramat on SWD fitness with respect to fecundity and surface barrier function at different stages.In our experiments,we applied spirotetramat mixed with baker's yeast and showed that females and males were not repelled by effective concentrations of this insecticide.We found that spirotetramat,by trend,lowers egg numbers laid by fed females.These eggs rapidly desiccate,and only a few larvae hatch.Spirotetramat is lethal to larvae and reduces survival of adult flies under low-humidity conditions.Taken together,based on our data,we propose to use yeast supplemented with spirotetramat and additional SWD-specific attractants in traps in non-crop areas in order to eradicate SWD populations before they infest crop production sites.展开更多
Background:Aconitum carmichaelii,the mother root of Aconitum,has a long-applied history for treating many diseases in China.Increased use of it has prompted significant concerns regarding its extensive cardiotoxicity ...Background:Aconitum carmichaelii,the mother root of Aconitum,has a long-applied history for treating many diseases in China.Increased use of it has prompted significant concerns regarding its extensive cardiotoxicity and neurotoxicity.The molecular mechanisms underlying A.carmichaelii-induced neurotoxicity are poorly understood.Methods:We took advantage of the zebrafish model to investigate the neurotoxic mechanism of A.carmichaelii.In addition to the behavior and neuronal activity testing,gene expression of neuronal oxidative stress,and apoptosis levels were also analyzed.Results:In contrast to the excitatory effect of low-dose A.carmichaelii decoction,hypoactivity of locomotor behavior,and neural activity,especially telencephalon,were detected in the 20 mg/mL group.High doses of A.carmichaelii induced excessive ROS bydownregulating DJ-1 and activating Nox5,and further triggered cell apoptosis through the bax/bcl2a-caspase-9 pathway in zebrafish larva.Mitochondrial protection-relatedgenes PinK1 and Parkin were upregulated to protect against mitochondrial dysfunction during cellular stress.The ROS scavenger-NAC significantly alleviated neurotoxicity in the 20mg/mL group.Conclusion:The study reveals the potential mechanism of A.carmichaelii-induced neurotoxicity and provides new insights in to a significant risk marker of A.carmichaelii poisoning.展开更多
文摘Insects occupy a broad range of habitats after terrestrialization and radiation from marine crustaceans 519 million years ago(Schwentner et al.,2017).They found themselves in a new environment,foremost jeopardizing them with low humidity,i.e.,dry or desiccation conditions.In addition,their co-evolution with land plants both as beneficial and maleficial companions exposed them to plant-produced xenobiotics(secondary metabolites)that as the plant defence molecules may have potential adverse effects on insects.Insects learned to cope with both situations,among others,through the evolution and activation of H-type ATP-binding cassette(ABC)transporters(Fig.1).Indeed,ABCH transporters are arthropod-specific ABC transporters that,in all kingdoms of living organisms,using ATP hydrolysis,transport molecules from one side of a membrane to the other,thereby influencing the physiological milieus of both compartments.
基金the National Natural Science Foundation of China(Grant No.31672364)the NSFC-DFG(Grant No.31761133021)+2 种基金Research Project Supported by Shanxi Scholarship Council of China(HGKY2019011)Special Talents Projects in Shanxi Province,China(201805D211019)the Program for Top Young Academic Leaders of Higher Learning Institutions of Shanxi(TYAL)2017.BM’s contribution was supported by the German Research Foundation(DFG grant MO1714/10-1).
文摘Wings are essential for insect fitness.A number of proteins and enzymes have been identified to be involved in wing terminal differentiation,which is characterized by the formation of the wing cuticle.Here,we addressed the question whether chitinase 10(Cht10)may play an important role in chitin organization in the wings of the fruit fly Drosophila melanogaster.Initially,we first found that Cht10 expression coincides with the expression of the chitin synthase coding gene kkv.This suggests that the respective proteins may cooperate during wing differentiation.In tissue-specific RNA interference experiments,we demonstrate that suppression of Cht10 causes an excess in chitin amounts in the wing cuticle.Chitin organization is severely disrupted in these wings.Based on these data,we hypothesize that Cht10 restricts chitin amounts produced by Kkv in order to ensure normal chitin organization and wing cuticle formation.In addition,we found by scanning electron microscopy that Cht10 suppression also affects the cuticle surface.In turn,cuticle inward permeability is enhanced in Cht10 Aess wings.Moreover,flies with reduced Cht 10 function are unable to fly.In conclusion,Cht10 is essential for wing terminal differentiation and function.
基金supported by the National Natural Science Foundation of China(31630057 and 31871954).
文摘Many holo-and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle(SC).To date,scholarly understanding of the SC composition and SC-related gene functions has been limited,especially for hemimetabolous insects.In this study,we initially performed transmission electron microscopic(TEM)observation and chitin staining of the SC in Nilaparvata lugens,a hemimetabolous rice pest known as the brown planthopper(BPH).We confirmed that the SC was a chitin-rich lamellar structure deposited gradually during the early embryogenesis.Parental RNA interference(RNAi)against Nilaparvata lugens chitin synthase 1(NlCHS1)in newly emerged and matured females resulted in decreases of egg hatchability by 100%and 76%,respectively.Ultrastructural analyses revealed loss of the lamellar structure of the SC in dsNlCHS1-treated eggs.According to temporal expression profiles,five cuticle protein coding genes,NlugCpr1/2/3/8/90,were specifically or highly expressed during the SC formation period,and NlugCpr1/2/3/90 were further detected in 72 h eggshells extract by ultra-performance liquid chromatography-tandem mass spectrometry/mass spectrometry.NlugCpr2/3/90 were likely three SC-specific cuticle proteins.TEM observations of the SC following parental RNAi against NlugCpr1/2/3/8/90 demonstrated that NlugCpr3/8/90 were essential for SC formation.The study provided an understanding of the SC formation process and SC-related cuticle proteins in BPHs,which offer potential targets for pest control in the egg stage as well.
基金This work was supported by the National Natural Science Foundation of China(31872972,31830076)the Shenzhen Science and Technology Program(KQTD20180411143628272)。
文摘Bioinsecticides are naturally-occurring substances from different sources that control insect pests.Ideal bioinsecticides should have low toxicity to non-target organisms.They should also be easily degraded in sewage treatment works and natural environments,highly effective in small quantities and affect target pests only.Public concerns about possible side-effects of synthetic pesticides have accelerated bioinsecticide research and development.However,to develop bioinsecticides into mainstream products,their high production costs,short shelf-life and often uncertain modes of action need to be considered.This review summarizes current progress on bioinsecticides which are categorized as biochemical insecticides and their derivatives,plant-incorporated protectants,and microbial bioinsecticides.The current constraints that prevent bioinsecticides from being widely used are discussed and future research directions are proposed.
基金supported by the National Natural Science Foundation of China(Grant No.3217050532170526)Natural Science Foundation of Shanxi Province(Grant No.20210302123473).
文摘Lipid homeostasis is crucial for growth and development of organisms.Several cytochrome P450 monooxygenases(CYPs)are involved in lipid metabolism.The function of Cyp3llal in the anterior midgut as a regulator of phosphatidylethanolamine(PE)metabolism in Drosophila melanogaster has been demonstrated,as depletion of Cyp31lal caused larval growth arrest that was partially rescued by supplying PE.In this study,we investigated the role of CYP311A1 in wing morphogenesis in Drosophila.Using the GAL4-UAS system,Cyp31lal was selectively knocked down in the wing disc.A deformed wing phenotype was observed in flies with reduced Cyp31lal transcripts.BODIPY and oil red O staining revealed a reduction of neutral lipids in the wing disc after the depletion of Cyp31lal.In addition,we observed an enhanced sensitivity to Eosin Y penetration in the wings of Cyp31lal knocked-down flies.Moreover,the reduction of CYP311A1 function in developing wings does not affect cell proliferation and apoptosis,but entails disordered Phalloidin or Cadherin distribution,suggesting an abnormal cell morphology and cell cortex structure in wing epithelial cells.Taken together,our results suggest that Cyp3llal is needed for wing morphogenesis by participating in lipid assembly and cell homeostasis.
基金supported by National Natural Science Foundation of China(NSFC31402021and NSFC31672364)2018 Special Talents Projects in Shanxi Province,China(201805D211019).
文摘Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of experiments.The Gal4/UAS system has been widely used to direct gene expression for studying complex genetic and biological problems in Drosophila melanogaster and other model organisms.Driven by a given tissue-specific Gal4,expressing UAS-transgene or UAS-RNAi(RNA interference)could be used to up-or down-regulate target gene expression,respectively.However,the efficiency of the Gal4/UAS system is roughly predefined by properties of transposon vector constructs and the insertion site in the transgenic stock.Here,we describe a simple way to modulate optomotor blind(omb)expression levels in its endogenous expression region of the wing disc.We co-expressed UAS-omb and UAS-omb-RNAi together under the control of dpp-Gal4 driver which is expressed in the omb expression region of the wing pouch.The repression effect is more sensitive to temperature than that of overexpression.At low temperature,overexpression plays a dominant role but the efficiency is attenuated by UAS-omb-RNAi.In contrast,at high temperature RNAi predominates in gene expression regulation.By this strategy,we could manipulate omb expression levels at a moderate level.It allows us to manipulate omb expression levels in the same tissue between overexpression and repression at different stages by temperature control.
基金the National Natural Science Foundation of China(Grant No.31672364,31761133021,32072419,31701794,31801749)the Pro-gram for Top Young Academic Leaders of Higher Learn-ing Institutions of Shanxi(TYAL)2017+1 种基金Scientific and Technological Innovation Programs of Higher Edu-cation Institutions in Shanxi(2017104)BM's contribu-tion was supported by the German Research Foundation(DFG grant MO1714/10-1).
文摘Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular intima of the foregut and hindgut are unclear.Here,we investigated the roles of their respective genes LmCDAI and Lm-CD42 in this process,in the hemimetabolous insect Locusta migratoria.Transcripts of LmCDAI and LmCDA2 were highly expressed both before and after molting in the foregut.In the hindgut,their expression was high only before molting.In both the foregut and hindgut,LmCDA1 protein was localized in the basal half of the chitin matrix(procuti-cle),whereas LmCDA2 was detected in the upper half of the procuticle.K nockdown of LmCDAI by RNA interference(RNAi)in 5th-instar nymphs caused no visible defcts of the hindgut cuticle.By contrast,the chitinous lamellae of the cuticular intima in the foregut of knockdown animals were less compact than in control animals.RNAi against LmCDA2 led to thickening of both the foregut and hindgut cuticles,with a greater number of thinner laminae than in the respective control cuticles.Taken together,our results show that LmCDAI and LmCDA2 have distinct,but overlapping,functions in chitin organization in the foregut cuticle.However,in the hindgut,this process seems independent of LmCDA1 activity but requires LmCDA2 function.Thus,the CDAs reflect tissue-specific differences in cuticular organization and function,which need further detailed molecular and histological analyses for full comprehension.
基金This work was supported by the National Natural Science Foundation of China(32001895,31630057 and 31871954)China Postdoctoral Science Foundation(2020M681874)BM was financed by the German Research Foundation(DFG)in cooperation with the National Natural Science Foundation of China(MO1714/10-1).
文摘Dear Editor,The insect cuticle is a multifunctional coat that defines and stabilizes the shape of the body,appendages and internal organs,serves as a barrier against water and chemical compounds,such as insecticides,prevents infection and protects against predators(Moussian,2010).The surface of insects is covered by a lipid layer composed of diverse hydrocarbons,wax esters,fatty acids,fatty alcohols,sterols and triglycerides.Delivery of lipids to the body surface occurs through the cuticle by a nano-canal system consisting of pore canals(PC)and wax canals(WC).
基金supported by the National Natural Science Foundation of China(Grant No.32170505,32170526)the NSFC-DFG(Grant No.31761133021)+2 种基金Natural Science Foundation of Shanxi Province(Grant No.20210302123473)Research Project Supported by Shanxi Scholarship Council of China(HGKY2019011)the Fund for Shanxi“1331 Project.”BM’s contribution was supported by the German Research Foundation(DFG grant MO1714/10-1).
文摘The polysaccharide chitin is a major scaffolding molecule in the insect cuticle.In order to be functional,both chitin amounts and chitin organization have been shown to be important parameters.Despite great advances in the past decade,the molecular mechanisms of chitin synthesis and organization are not fully understood.Here,we have characterized the function of the Chitinase 6(Cht6)in the formation of the wing,which is a simple flat cuticle organ,in the fruit fly Drosophila melanogaster.Reduction of Cht6 function by RNA interference during wing development does not affect chitin organization,but entails a thinner cuticle suggesting reduced chitin amounts.This phenotype is opposed to the one reported recently to be caused by reduction of Cht10 expression.Probably as a consequence,cuticle permeability to xenobiotics is enhanced in Cht6-less wings.We also observed massive deformation of these wings.In addition,the shape of the abdomen is markedly changed upon abdominal suppression of Cht6.Finally,we found that suppression of Cht6 transcript levels influences the expression of genes coding for enzymes of the chitin biosynthesis pathway.This finding indicates that wing epidermal cells respond to activity changes of Cht6 probably trying to adjust chitin amounts.Together,in a working model,we propose that Cht6-introduced modifications of chitin are needed for chitin synthesis to proceed correctly.Cuticle thickness,according to our hypothesis,is in turn required for correct organ or body part shape.The molecular mechanisms of this processes shall be characterized in the future.
文摘Chitin is the second most abundant polysaccharide on earth. It is produced at the apical side of epidermal, tracheal, fore-, and hindgut epithelial cells in insects as a central component of the protective and supporting extracellular cuticle. Chitin is also an important constituent of the midgut peritrophic matrix that encases the food supporting its digestion and protects the epithelium against invasion by possibly ingested pathogens. The enzyme producing chitin is a glycosyltransferase that resides in the apical plasma membrane forming a pore to extrude the chains of chitin into the extracellular space. The apical plasma membrane is not only a platform for chitin synthases but, probably through its shape and equipment with distinct factors, also plays an important role in orienting and organizing chitin fibers. Here, I review findings on the cellular and molecular constitution of the apical plasma membrane of chitin-producing epithelia mainly focusing on work done in the fruit fly Drosophila melanogaster.
基金Open access funding enabled and organized by Projekt DEAL.
文摘With climate change,the spotted-wing Drosophila(SWD,Drosophila suzukii)invades a great number of fruit production regions worldwide.A plethora of insecticides are being applied for management of this pest.As expected,SWD develops resistance against some potent insecticides or is rather insensitive to some others.Therefore,there is an urgent need to identify and characterize alternative insecticides to control SWD populations.Here,we have studied the effects of the orally applied inhibitor of the fatty acid synthesis pathway spirotetramat on SWD fitness with respect to fecundity and surface barrier function at different stages.In our experiments,we applied spirotetramat mixed with baker's yeast and showed that females and males were not repelled by effective concentrations of this insecticide.We found that spirotetramat,by trend,lowers egg numbers laid by fed females.These eggs rapidly desiccate,and only a few larvae hatch.Spirotetramat is lethal to larvae and reduces survival of adult flies under low-humidity conditions.Taken together,based on our data,we propose to use yeast supplemented with spirotetramat and additional SWD-specific attractants in traps in non-crop areas in order to eradicate SWD populations before they infest crop production sites.
基金National Key Research and Development Program,Grant/Award Number:2021YFF1200600China Postdoctoral Science Foundation,Grant/Award。
文摘Background:Aconitum carmichaelii,the mother root of Aconitum,has a long-applied history for treating many diseases in China.Increased use of it has prompted significant concerns regarding its extensive cardiotoxicity and neurotoxicity.The molecular mechanisms underlying A.carmichaelii-induced neurotoxicity are poorly understood.Methods:We took advantage of the zebrafish model to investigate the neurotoxic mechanism of A.carmichaelii.In addition to the behavior and neuronal activity testing,gene expression of neuronal oxidative stress,and apoptosis levels were also analyzed.Results:In contrast to the excitatory effect of low-dose A.carmichaelii decoction,hypoactivity of locomotor behavior,and neural activity,especially telencephalon,were detected in the 20 mg/mL group.High doses of A.carmichaelii induced excessive ROS bydownregulating DJ-1 and activating Nox5,and further triggered cell apoptosis through the bax/bcl2a-caspase-9 pathway in zebrafish larva.Mitochondrial protection-relatedgenes PinK1 and Parkin were upregulated to protect against mitochondrial dysfunction during cellular stress.The ROS scavenger-NAC significantly alleviated neurotoxicity in the 20mg/mL group.Conclusion:The study reveals the potential mechanism of A.carmichaelii-induced neurotoxicity and provides new insights in to a significant risk marker of A.carmichaelii poisoning.
