Low-density lipoprotein receptor-related protein 2(LRP2)is required for lipid export in the midgut of the migratory locust,Locusta migratoria

Low-density lipoprotein receptor-related protein 2(LRP2)is a multifunctional endocytic receptor expressed in epithelial cells.In mammals,it acts as an endocytic receptor that mediates the cellular uptake of cholesterol-containing apolipoproteins to maintain lipid homeostasis.However,little is known about the role of LRP2 in lipid homeostasis in insects.In the present study,we investigated the function of LRP2 in the migratory locust Locusta migratoria(LmLRP2).The mRNA of LmLRP2 is widely distributed in various tissues,including integument,wing pads,foregut,midgut,hindgut,Malpighian tubules and fat body,and the amounts of LmLRP2 transcripts decreased gradually in the early stages and then increased in the late stages before ecdysis during the nymphal developmental stage.Fluorescence immunohistochemistry revealed that the LmLRP2 protein is mainly located in cellular membranes of the midgut and hindgut.Using RNAi to silence LmLRP2 caused molting defects in nymphs(more than 60%),and the neutral lipid was found to accumulate in the midgut and surface of the integument,but not in the fat body,of dsLmLRP2-treated nymphs.The results of a lipidomics analysis showed that the main components of lipids(diglyceride and triglyceride)were significantly increased in the midgut,but decreased in the fat body and hemolymph.Furthermore,the content of total triglyceride was significantly increased in the midgut,but markedly decreased in the fat body and hemolymph in dsLmLRP2-injected nymphs.Our results indicate that LmLRP2 is located in the cellular membranes of midgut cells,and is required for lipid export from the midgut to the hemolymphand fat body in locusts.

Development and formation of wing cuticle based on transcriptomic analysis in Locusta migratoria during metamorphosis

Wings are an important flight organ of insects.Wing development is a complex process controlled by a series of genes.The flightless wing pad transforms into a mature wing with the function of migratory flight during the nymphto-adult metamorphosis.However,the mechanism of wing morphogenesis in locusts is still unclear.This study analyzed the microstructures of the locust wing pads at pre-eclosion and the wings after eclosion and performed the comparative transcriptome analysis.RNA-seq identified 25,334 unigenesand 3,430 differentially expressed genes(DEGs)(1,907 up-regulated and 1,523 down-regulated).The DEGs mainly included cuticle development(LmACPs),chitin metabolism(Lm Idgf4),lipid metabolism-related genes,cell adhesion(Integrin),zinc finger transcription factors(LmSalm,LmZF593 andLmZF521),and others.Functional analysis based on RNA interference and hematoxylin and eosin(H&E)staining showed that the three genes encoded zinc finger transcription factors are essential for forming wing cuticle and maintaining morphology in Locusta migratoria.Finally,the study found that the LmSalm regulates the expression of LmACPs in the wing pads at pre-eclosion,and LmZF593 and LmZF521 regulate the expression of LmIntegrin/LmIdgf4/LmHMT420 in the wings after eclosion.This study revealed that the molecular regulatory axis controls wing morphology in nymphal and adult stages of locusts,offering a theoretical basis for the study of wing development mechanisms in hemimetabolous insects.

Timing of mineralization at the Shihu gold deposit in the middle segment of the Taihang Mountain, China

The Shihu gold deposit, located in the middlesouth section of the core of the Fuping mantle branch structure, is hosted in the Archean Fuping Group and adjacent to the quartz diorite porphyrite. The gold deposit is the only large gold deposit with reserves of more than 30 tons gold discovered in western Hebei Province so far. In order to constrain the timing of mineralization of this ore deposit, this paper focuses on the isotopic dating of zircon and pyrite. Zircons in gold-bearing quartz veins are magmatic in origin and no hydrothermal zircon has been found in such quartz veins, indicating that zircons were derived from the wall rocks. U–Pb ages of zircons fall mainly in the two domains: 2492 ± 82 and 136 ± 4 Ma, respectively,indicative of the contribution of the Fuping-Group TTG gneiss and Yanshanian igneous rocks, respectively. The Re–Os isotopic compositions of pyrites in the gold-bearing quartz veins yield an isochron age of 127 ± 31 Ma. Combined with other dating results, we suggest that the main metallogenic age of the Shihu gold deposit is 120–127 Ma.

Role of CYP311A1 in wing development of Drosophila melanogaster

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.

Clathrin heavy chain is essential for the development and reproduction of Locusta migratoria

Clathrin heavy chain(Chc)is a constituent of clathrin-coated vesicles and serves important functions in endocytosis and intracellular membrane trafficking but ap-pears to have physiological roles also at the organismal level.Most of what we know about Chc functions originates from studies performed in fungal or vertebrate cells.How-ever,the physiological functions of Chc in insects remain poorly understood.Here,we identified a Chc ortholog from a Locusta migratoria transcriptome database.RT-qPCR revealed that LmChc was constitutively expressed in fifth-instar nymphs.In this develop-mental stage,LmChc showed the highest expression in the ovary followed by hemolymph,testis,hindgut,midgut,and foregut.In isolated hemocytes,we detected the Chc protein in patches at the plasma membrane.To examine the role of LmChc in L.migratoria during development,RNA interference was performed by injecting dsRNA into the early fifth-instar nymphs.Silencing of LmChc caused a lethal phenotype with molting defect from nymph to adult.In addition,silencing of LmChc resulted in abnormal development of the ovaries,the size of which was significantly smaller than that in controls.Taken together,our results suggest that LmChc is a vital gene in L.migratoria that plays an important role in growth,development,and reproduction.LmChc may be used as an efficient RNAi target gene for developing dsRNA-based biological insecticides to manage insect pests.

Lethal giant larvae gene is required for normal nymphal development and midgut morphogenesis in Locusta migratoria

Disruption of morphogenesis,an essential process in organismal development,can lead to disruption of biological processes,reduction in fitness,or even death of an organism.The roles of lethal giant larvae(Lgl)protein in maintaining tissue organization have been studied extensively in mammals,but little is known about this gene's roles in promoting correct tissue morphogenesis in insects.In this study,we identified an Lgl ortholog in Locusta migratoria.RT-qPCR results revealed that LmLgl was constitutively expressed during third,fourth,and fifth instar nymphs.Furthermore,LmLgl showed highest expression in the ovary followed by wing pads,midgut,hindgut,Malpighian tubules,and foregut of the third-instar nymphs.To examine the role of LmLgl in L.migratoria development,RNA interference was performed during nymphal stages.Silencing of LmLgl increased body size but decreased bodyweight by 9.0%.Histological sections of the midgut revealed abnormal large masses of disordered epithelial cells in dsLmLgl-injected nymphs.In addition,downregulation of LmLgl transcript levels significantly altered the morphological structure in midgut,resulting in the formation of tumor-like structures.Our results indicated that LmLgl may act as a tumor-suppressor gene,which plays an essential role in maintaining a normal morphological structure in the midgut of L.migratoria.Our results also suggest that LmLgl may be explored as a potential target for developing dsRNA-based biological pesticides for managing insect pests.