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Guoxiong Peng - One of the best experts on this subject based on the ideXlab platform.
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disruption of an adenylate forming reductase required for conidiation increases virulence of the insect pathogenic fungus metarhizium acridum by enhancing cuticle invasion
Pest Management Science, 2020Co-Authors: Hongjuan Wang, Nemat O. Keyhani, Guoxiong PengAbstract:BACKGROUND: Metarhizium acridum, is a specific acridid pathogen developed for use against the migratory locust (Locusta migratoria manilensis). Adenylate-forming reductases (AFRs) include enzymes that are involved in natural product biosynthesis. Here, we genetically characterize the functions of a class IV AFR in M. acridum (MaAfrIV ) on fungal development and virulence. RESULTS: Gene expression analyses indicated MaAfrIV was induced on locust wings early during the infection process. Surprisingly, loss of MaAfrIV increased virulence (25.20% decrease in the median lethal time) against the locust in topical bioassays but was no different than the wild type when the cuticle was bypassed by direct infection of conidia into the insect hemocoel. Virulence markers including protease (Pr1) expression and appressorial turgor pressure were higher in the mutant than the parent strain. No difference was seen in the expression of host immune genes (Toll pathway) or in polyphenol oxidase (PPO) activity in locusts infected by the ΔMaAfrIV or wild type strains. However, the ΔMaAfrIV strain was unable to successfully sporulate on dead cadavers. CONCLUSION: Disruption of MaAfrIV increased fungal virulence by promoting insect cuticle invasion without altering host immune response or fungal immune evasion. Although loss of MaAfrIV conferred an apparent benefit to the fungus in terms of enhanced virulence, a significant trade-off was seen in the inability of the fungus to sporulate on the cadaver. As conidiation on the cadaver is essential for subsequent propagation in the environment, loss of MaAfrIV can reduce the engineering strains survivability in the field and improve the safety. © 2019 Society of Chemical Industry.
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the acid trehalase atm1 contributes to the in vivo growth and virulence of the entomopathogenic fungus metarhizium acridum
Fungal Genetics and Biology, 2015Co-Authors: Guoxiong PengAbstract:Abstract For pathogens, the ability to acquire available nutrients in a host is a key to their survival and replication. Entomopathogenic fungi of the genus Metarhizium secrete trehalase, which enables them to use trehalose, the predominant sugar in insects. Here, the roles of the acid trehalase gene ( ATM1 ) in the in vivo growth and virulence of Metarhizium acridum were investigated. Phenotypic analysis showed that disruption of ATM1 severely reduced fungal growth on exogenous trehalose as the sole carbon source. Bioassays showed that ATM1 disruption impaired the virulence of M. acridum against the host insect Locusta migratoria . The ATM1- disruption strain (Δ ATM1 ) grown more slowly than the wild-type strain (WT) and complemented transformant (CP) in locust blood, which was consistent with the activity of acid trehalase in the hemolymph of infected locusts. Correspondingly, the trehalose concentration in locusts infected by Δ ATM1 was significantly higher than in those infected by WT or CP. Thus, ATM1 disruption led to a significant reduction in virulence by adversely affecting the fungal growth in insect hemolymph, which resulted from the inability of the mutant strain to use trehalose.
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integration of an insecticidal scorpion toxin bjαit gene into metarhizium acridum enhances fungal virulence towards Locusta migratoria manilensis
Pest Management Science, 2015Co-Authors: Guoxiong PengAbstract:BACKGROUND Entomopathogenic fungi have been developed as biopesticides, but poor efficacy has blocked their application. One approach to improving virulence is by genetic manipulation. BjαIT from the venom of Buthotus judaicus is an insect-selective neurotoxin. To clarify the insecticidal potency of BjαIT as a virulence candidate in microbial biocontrol agents, the entomopathogenic fungus Metarhizium acridum was genetically modified with BjαIT, and its resulting activity against locusts (Locusta migratoria manilensis) was assessed. RESULT In comparison with the wild-type strain, the engineered isolate BjαIT-102 grew significantly quicker in locust haemolymph. Correspondingly, the median lethal dose (LC50) for BjαIT-102 was 18.2-fold lower, and the median lethal times (LT50) for BjαIT-102 were reduced by 28.1 and 30.4%, respectively, after topical inoculation and injection. BjαIT-102 formed conidia on dead locusts, although the conidial yield was reduced 1.58-fold. Moreover, there were no significant differences in germination and appressorium formation between the BjαIT-102 and wild-type strains. CONCLUSION Expression of BjαIT in M. acridum significantly increased virulence against locusts by shortening the in vivo infection period without affecting conidium formation on the carcasses. This study demonstrated that engineering entomopathogenic fungi to incorporate BjαIT offers great potential for increasing their virulence. © 2014 Society of Chemical Industry
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expression of scorpion toxin lqhit2 increases the virulence of metarhizium acridum towards Locusta migratoria manilensis
Journal of Industrial Microbiology & Biotechnology, 2014Co-Authors: Guoxiong PengAbstract:LqhIT2 is an insect-specific neurotoxin from the venom of scorpion. In this study, the LqhIT2 gene was introduced into the entomopathogenic fungus, Metarhizium acridum. The virulence of the genetically modified strain MaLqhIT2 was then evaluated against locusts (Locusta migratoria manilensis). Compared with the wild-type strain, the median lethal cell density (LC50) for MaLqhIT2 was a 22.6-fold lower, and the median times to death (LT50) for MaLqhIT2 were reduced by 30.3 and 29.6 %, respectively, after topical inoculation and injection. MaLqhIT2 also grew significantly faster in the hemolymph than wild-type strain. There were no significant differences in germination, appressorium formation and sporulation in locust carcasses between the MaLqhIT2 and wild-type strain. These results indicate that LqhIT2 increased the virulence of M. acridum towards locusts by shortening the in vivo infection period, without affecting cuticle penetration or conidia formation in the carcasses. LqhIT2 thus shows considerable potential for increasing fungal virulence against locusts.
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field trials of metarhizium anisopliae var acridum ascomycota hypocreales against oriental migratory locusts Locusta migratoria manilensis meyen in northern china
Crop Protection, 2008Co-Authors: Guoxiong Peng, Zhongkang Wang, Dengyu ZengAbstract:Abstract During 2002–2006, nymph bands of Locusta migratoria manilensis (Meyen) were treated by ground and aerial applications in 6000 ha of grasslands and the nearby beach of Yellow river using a soybean oil miscible suspension ULV formulation of Metarhizium anisopliae var. acridum isolate CQMa102. The formulation was also applied in Tianjin, Henan, Hebei, Shandong and Shanxi provinces of Northern China by ground and aerial applications. During field studies, cage tests were carried out in corresponding field plots in order to estimate the mortality accurately. Doses of 3.3×10 12 and 5.0×10 12 conidia ha −1 were equally effective and caused 90% mortality 9–13 days after treatment. In the ground spray trial, 3.3×10 12 conidia ha −1 killed >90% of L. migratoria manilensis 11–15 days after treatment in a wide variety of vegetation and weather conditions. The decline of locust populations was slower where vegetation was taller and denser. In the aerial spray treatment, the final percent survival of locusts was lowered to 10% at 11 and 14 days in the field cage and open field locusts, respectively. Furthermore, the M. anisopliae oil miscible suspension formulation did not appear to harm natural enemies of locusts in the field.
Le Kang - One of the best experts on this subject based on the ideXlab platform.
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4 vinylanisole is an aggregation pheromone in locusts
Nature, 2020Co-Authors: Qiaoqiao Yu, Dafeng Chen, Pengcheng Yang, Jia Yu, Xianhui Wang, Le KangAbstract:Locust plagues threaten agricultural and environmental safety throughout the world1,2. Aggregation pheromones have a crucial role in the transition of locusts from a solitary form to the devastating gregarious form and the formation of large-scale swarms3,4. However, none of the candidate compounds reported5-7 meet all the criteria for a locust aggregation pheromone. Here, using behavioural assays, electrophysiological recording, olfactory receptor characterization and field experiments, we demonstrate that 4-vinylanisole (4VA) (also known as 4-methoxystyrene) is an aggregation pheromone of the migratory locust (Locusta migratoria). Both gregarious and solitary locusts are strongly attracted to 4VA, regardless of age and sex. Although it is emitted specifically by gregarious locusts, 4VA production can be triggered by aggregation of four to five solitary locusts. It elicits responses specifically from basiconic sensilla on locust antennae. We also identified OR35 as a specific olfactory receptor of 4VA. Knockout of OR35 using CRISPR-Cas9 markedly reduced the electrophysiological responses of the antennae and impaired 4VA behavioural attractiveness. Finally, field trapping experiments verified the attractiveness of 4VA to experimental and wild populations. These findings identify a locust aggregation pheromone and provide insights for the development of novel control strategies for locusts.
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octopamine and tyramine signaling in locusts relevance to olfactory decision making
2016Co-Authors: Xiaojiao Guo, Le KangAbstract:Abstract Swarm-forming locusts are among the most favored subjects in the study of insect neurobiology and behavior. The migratory locust (Locusta migratoria) exhibits population-density-dependent transitional decision-making (attraction versus repulsion). Individual olfactory decision-making is essential in the phase polyphenism of locusts. Here, we summarize the progress of octopamine and tyramine signaling in locusts and discuss the relevance of these chemicals to olfactory decision-making in Locusta. Octopamine and its receptor α (OARα) can mediate olfactory attraction elicited by volatiles from gregarious locusts, whereas tyramine and its receptor (TAR) can modulate the repulsion response toward those volatiles. Octopamine–OARα and tyramine–TAR signaling antagonistically modulate the transitional olfactory decision-making during phase change, suggesting a seesaw manner utilized in this process. The seesaw mode by which these two signaling pathways function may provide vital clues to neurogenetic and neurophysiological mechanisms underlying individual olfactory decision-making.
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chapter 15 octopamine and tyramine signaling in locusts relevance to olfactory decision making
Trace Amines and Neurological Disorders#R##N#Potential Mechanisms and Risk Factors, 2016Co-Authors: Xiaojiao Guo, Le KangAbstract:Swarm-forming locusts are among the most favored subjects in the study of insect neurobiology and behavior. The migratory locust (Locusta migratoria) exhibits population-density-dependent transitional decision-making (attraction versus repulsion). Individual olfactory decision-making is essential in the phase polyphenism of locusts. Here, we summarize the progress of octopamine and tyramine signaling in locusts and discuss the relevance of these chemicals to olfactory decision-making in Locusta. Octopamine and its receptor α (OARα) can mediate olfactory attraction elicited by volatiles from gregarious locusts, whereas tyramine and its receptor (TAR) can modulate the repulsion response toward those volatiles. Octopamine–OARα and tyramine–TAR signaling antagonistically modulate the transitional olfactory decision-making during phase change, suggesting a seesaw manner utilized in this process. The seesaw mode by which these two signaling pathways function may provide vital clues to neurogenetic and neurophysiological mechanisms underlying individual olfactory decision-making.
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argonaute 1 is indispensable for juvenile hormone mediated oogenesis in the migratory locust Locusta migratoria
Insect Biochemistry and Molecular Biology, 2013Co-Authors: Jiasheng Song, Le Kang, Feng Jiang, Wei Guo, Shutang ZhouAbstract:Juvenile hormone (JH) is the primary hormone controlling vitellogenesis and oocyte maturation in the migratory locust Locusta migratoria, an evolutionarily primitive insect species with panoistic ovaries. However, molecular mechanisms of locust oogenesis remain unclear and the role of microRNA (miRNA) in JH mediated locust vitellogenesis and oocyte maturation has not been explored. Using miRNA sequencing and quantification with small RNA libraries derived from fat bodies of JH-deprived versus JH analog-exposed female adult locusts, we have identified 83 JH up-regulated and 60 JH down-regulated miRNAs. QRT-PCR validation has confirmed that transcription of selected miRNAs responded to JH administration and correlated with changes in endogenous hemolymph JH titers. Depletion of Argonaute 1 (Ago1), a key regulator of miRNA biogenesis and function by RNAi in female adult locusts dramatically decreased the expression of vitellogenin (Vg) and severely impaired follicular epithelium development, terminal oocyte maturation and ovarian growth. Our data indicate that Ago1 and Ago1-dependent miRNAs play a crucial role in locust vitellogenesis and egg production.
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altered immunity in crowded locust reduced fungal metarhizium anisopliae pathogenesis
PLOS Pathogens, 2013Co-Authors: Y L Wang, Pengcheng Yang, Le KangAbstract:The stress of living conditions, similar to infections, alters animal immunity. High population density is empirically considered to induce prophylactic immunity to reduce the infection risk, which was challenged by a model of low connectivity between infectious and susceptible individuals in crowded animals. The migratory locust, which exhibits polyphenism through gregarious and solitary phases in response to population density and displays different resistance to fungal biopesticide (Metarhizium anisopliae), was used to observe the prophylactic immunity of crowded animals. We applied an RNA-sequencing assay to investigate differential expression in fat body samples of gregarious and solitary locusts before and after infection. Solitary locusts devoted at least twice the number of genes for combating M. anisopliae infection than gregarious locusts. The transcription of immune molecules such as pattern recognition proteins, protease inhibitors, and anti-oxidation proteins, was increased in prophylactic immunity of gregarious locusts. The differentially expressed transcripts reducing gregarious locust susceptibility to M. anisopliae were confirmed at the transcriptional and translational level. Further investigation revealed that locust GNBP3 was susceptible to proteolysis while GNBP1, induced by M. anisopliae infection, resisted proteolysis. Silencing of gnbp3 by RNAi significantly shortened the life span of gregarious locusts but not solitary locusts. By contrast, gnbp1 silencing did not affect the life span of both gregarious and solitary locusts after M. anisopliae infection. Thus, the GNBP3-dependent immune responses were involved in the phenotypic resistance of gregarious locusts to fungal infection, but were redundant in solitary locusts. Our results indicated that gregarious locusts prophylactically activated upstream modulators of immune cascades rather than downstream effectors, preferring to quarantine rather than eliminate pathogens to conserve energy meanwhile increasing the “distance” of infectious and target individuals. Our study has obvious implications for bio-pesticides management of crowded pests, and for understanding disease epidemics and adaptiveness of pathogens.
Jianzhen Zhang - One of the best experts on this subject based on the ideXlab platform.
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two fatty acid synthase genes from the integument contribute to cuticular hydrocarbon biosynthesis and cuticle permeability in Locusta migratoria
Insect Molecular Biology, 2020Co-Authors: Yang Yang, Xiaoming Zhao, Niu Niu, Yiyan Zhao, Weimin Liu, Bernard Moussian, Jianzhen ZhangAbstract:Lipids of the insect cuticle have important roles in resistance against the arid environment and invasion of foreign substances. Fatty acid synthase (FAS) is an important enzyme of the insect lipid synthesis pathway. In the present study, we identified three FAS genes from transcriptome data of the migratory locust, Locusta migratoria, based on bioinformatics analyses. Among them, two FAS genes (LmFAS1 and LmFAS3) are highly expressed in the integument of fifth instar nymphs. Suppression of LmFAS1 and LmFAS3 by RNA interference caused lethality during ecdysis or shortly after moulting. The weight of the locusts and the content of lipid droplets were reduced compared with those of the control. The results of gas chromatography-mass spectrometry analysis showed that knockdown of LmFAS3 led to a decrease of both cuticular hydrocarbons and inner hydrocarbons (CHCs and IHCs) contents, especially the content of methyl branched hydrocarbons. By contrast, knockdown of LmFAS1 only resulted in a decrease in the IHC content, but not that of CHCs. By consequence, in LmFAS1- and LmFAS3-suppressed locusts, hydrocarbon deficiency reduced desiccation resistance and enhanced cuticle permeability and sensitivity to insecticides. These results indicate that LmFAS1 and LmFAS3 are essential for hydrocarbon production and cuticle permeability, which play influential roles in waterproofing the insect cuticle.
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transcriptome wide survey gene expression profiling and exogenous chemical induced transcriptional responses of cytochrome p450 superfamily genes in migratory locust Locusta migratoria
Insect Biochemistry and Molecular Biology, 2018Co-Authors: Xueyao Zhang, Jianzhen Zhang, Xiaolin Kang, Kristopher Silver, Kun Yan ZhuAbstract:Cytochrome P450 monooxygenases (CYPs) belong to a large superfamily of heme-containing enzymes catalyzing at least 60 different types of chemically distinct reactions. Insect CYPs play key roles in biotransformation of insecticides and plant chemicals, and are implicated in insecticide resistance and insect adaptation to their host plants. Insect CYPs are well studied in model insects, but little is known about the CYP superfamily in paurometabolous insects. We employed Illumina sequencing technology to identify 71 partial and 78 full-length open reading frames (ORFs) of LmCYP genes from the migratory locust (Locusta migratoria), one of the most destructive paurometabolous insect pests in the world. Seventy-eight LmCYPs with complete ORFs were formally named and classified into 19 families and 43 subfamilies. The majority of LmCYPs were mainly expressed in nymphal and adult stages, but LmCYP expression varied widely among thirteen different tissues examined. Regulatory elements were predicted in the promoter regions of LmCYP genes, and subsequent exposure of locusts to 12 different exogenous chemicals showed that 2-tridecanone and xanthotoxin were the most effective at increasing LmCYP expression. Our results represent the first transcriptome-wide analysis of the LmCYP superfamily from migratory locust, and provide a foundation for understanding the physiological functions, functional diversity, evolution, and regulatory mechanisms controlling the expression of the CYP gene superfamily in the locust.
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identification of lmuap1 as a 20 hydroxyecdysone response gene in the chitin biosynthesis pathway from the migratory locust Locusta migratoria
Insect Science, 2018Co-Authors: Xiaojian Liu, Yawen Sun, Jianzhen ZhangAbstract:In Locusta migratoria, we found that two chitin biosynthesis genes, UDP N-acetylglucosamine pyrophosphorylase gene LmUAP1 and chitin synthase gene LmCHS1, are expressed mainly in the integument and are responsible for cuticle formation. However, whether these genes are regulated by 20-hydroxyecdysone (20E) is still largely unclear. Here, we showed the developmental expression pattern of LmUAP1, LmCHS1 and the corresponding 20E titer during the last instar nymph stage of locust. RNA interference (RNAi) directed toward a common region of the two isoforms of LmEcR (LmEcRcom) reduced the expression level of LmUAP1, while there was no difference in the expression of LmCHS1. Meantime, injection of 20E in vivo induced the expression of LmUAP1 but not LmCHS1. Further, we found injection-based RNAi of LmEcRcom resulted in 100% mortality. The locusts failed to molt with no apolysis, and maintained in the nymph stage until death. In conclusion, our preliminary results indicated that LmUAP1 in the chitin biosynthesis pathway is a 20E late-response gene and LmEcR plays an essential role in locust growth and development, which could be a good potential target for RNAi-based pest control.
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characterization of a midgut specific chitin synthase gene lmchs2 responsible for biosynthesis of chitin of peritrophic matrix in Locusta migratoria
Insect Biochemistry and Molecular Biology, 2012Co-Authors: Xiaojian Liu, Jianzhen Zhang, Kun Yan Zhu, Huanhuan ZhangAbstract:Chitin, an essential component of peritrophic matrix (PM), is produced by a series of biochemical reactions. Chitin synthase plays a crucial role in chitin polymerization in chitin biosynthetic pathway. In this study, we identified and characterized a full-length cDNA of chitin synthase 2 gene (LmCHS2) from Locusta migratoria. The cDNA contains an open reading frame of 4569 nucleotides that encode 1523 amino acid residues, and 76- and 373-nucleotides for 5′- and 3′-noncoding regions, respectively. Analysis of LmCHS2 transcript in different tissues of the locust by using real-time quantitative PCR indicated that LmCHS2 was exclusively expressed in midgut and gastric caeca (a part of the midgut). The highest expression was found in the anterior midgut with a decline of the transcript level from the anterior to posterior regions. During growth and development of locusts, there was only a slight expression in eggs, but the expression gradually increased from nymphs to adults. In situ hybridization further revealed that LmCHS2 transcript mainly presented in the apical regions of brush border forming columnar cells of gastric caeca. LmCHS2 dsRNA was injected to fifth-instar nymphs to further explore biological functions of LmCHS2. Significantly down-regulated transcript of LmCHS2 resulted in a cessation of feeding and a high mortality of the insect. However, no visible abnormal morphological change of locusts was observed until insects molted to adults. After dissection, we found that the average length of midguts from the LmCHS2 dsRNA-injected locusts was shorter than that of the control insects that were injected with dsGFP. Furthermore, microsection of midguts showed that the PM of the LmCHS2 dsRNA-injected nymphs was amorphous and thin as compared with the controls. Our results demonstrate that LmCHS2 is responsible for the biosynthesis of chitin associated with PM and plays an essential role in locust growth and development.
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silencing of two alternative splicing derived mrna variants of chitin synthase 1 gene by rnai is lethal to the oriental migratory locust Locusta migratoria manilensis meyen
Insect Biochemistry and Molecular Biology, 2010Co-Authors: Jianzhen Zhang, Xiaojian Liu, Jianqin Zhang, Yi Sun, Yaping Guo, Kun Yan ZhuAbstract:Chitin synthases are crucial enzymes responsible for chitin biosynthesis in fungi, nematodes and arthropods. We characterized two alternative splicing-derived variants of chitin synthase 1 gene (LmCHS1) from the oriental migratory locust, Locusta migratoria manilensis (Meyen). Each cDNA of the two variants (LmCHS1A and LmCHS1B) consists of 5116 nucleotides that include a 4728-nucleotide open reading frame (ORF) encoding 1576 amino acid residues, and 67- and 321-bp non-coding regions at the 5′- and 3′-ends of the cDNA, respectively. The two variants differ only in one exon consisting of 177 nucleotides that encode 59 amino acid residues. The amino acid sequences within this alternative splicing region are 75% identical between the two variants. Both variants were expressed in all the developmental stages. However, LmCHS1A was predominately expressed in the integument whereas LmCHS1B was mainly expressed in the trachea. Our RNAi-based gene silencing study resulted in a dramatic reduction in the levels of the corresponding mRNA in the locust nymphs injected with dsRNA of LmCHS1, or either of its two variants, LmCHS1A and LmCHS1B. Consequentially, 95, 88 and 51% of mortalities were observed in the locusts injected with the LmCHS1, LmCHS1A and LmCHS1B dsRNA, respectively. The phenotypes resulted from the injection of LmCHS1A dsRNA were similar to those from the injection of LmCHS1 dsRNA, whereas the locusts injected with LmCHS1B dsRNA exhibited crimpled cuticle phenotype. Our results suggest that both variants of chitin synthase 1 are essential for insect growth and development.
Shigui Wang - One of the best experts on this subject based on the ideXlab platform.
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transcriptome analysis of the molecular mechanism underlying immunity and reproduction trade off in Locusta migratoria infected by micrococcus luteus
PLOS ONE, 2019Co-Authors: Shaohua Wang, Xiaojun Liu, Zhiyong Xia, Guoqiang Xie, Bin Tang, Shigui WangAbstract:Immune response and reproductive success are two vital energy-consuming processes in living organisms. However, it is still unclear which process is prioritized when both are required. Therefore, the present study was designed to examine this question arising for one of the world's most destructive agricultural pests, the migratory locust, Locusta migratoria. Transcripts from the ovaries and fat bodies of newly emerged locusts were analyzed, using RNA-seq based transcriptome and qualitative real-time PCR, at 4 h and 6 d after being infected with the gram-positive bacteria Micrococcus luteus. Changes in the main biological pathways involved in reproduction and immunization were analyzed using bioinformatics. After 4 h of infection, 348 and 133 transcripts were up- and down-regulated, respectively, whereas 5699 and 44 transcripts were up- and down-regulated, respectively, at 6 d after infection. Moreover, KEGG analysis indicated that vital pathways related with immunity and reproduction, such as Insulin resistance, FoxO signaling, Lysosome, mTOR signaling, and Toll-like receptor signaling pathways were up-regulated. Among the differentially expressed genes, 22 and 17 were related to immunity and reproduction, respectively. The expression levels of PPO1 and antimicrobial peptide defensin 3 were increased (log2FC = 5.93 and 6.75, respectively), whereas those of VgA and VgB were reduced (log2FC = -17.82 and -18.13, respectively). These results indicated that locust allocate energy and resources to maintain their own survival by increasing immune response when dealing with both immune and reproductive processes. The present study provides the first report of expression levels for genes related with reproduction and immunity in locusts, thereby providing a reference for future studies, as well as theoretical guidance for investigations of locust control.
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transcriptome analysis of the molecular mechanism underlying immunity and reproduction trade off in Locusta migratoria infected by micrococcus luteus
bioRxiv, 2019Co-Authors: Shigui Wang, Shaohua Wang, Xiaojun Liu, Zhiyong Xia, Guoqiang Xie, Bin TangAbstract:Abstract Immune response and reproductive success are two of the main energy-consuming processes in living organisms. However, it is unclear which process is prioritized when both are required. Therefore, the present study was designed to examine this question using one of the world’s most destructive agricultural pests, the migratory locust Locusta migratoria. Transcripts from the ovaries and fat bodies of newly emerged locusts were analyzed, using RNA-seq based transcriptome and qualitative real-time PCR, at 4 h and 6 d after being infected with the gram-positive bacteria Microcroccus luteus, and changes in the main biological pathways involved in reproduction and immunization were analyzed using bioinformatics. At 4 h after infection, 348 and 133 transcripts were up- and down-regulated, respectively, whereas 5699 and 44 transcripts were up- and down-regulated, respectively, at 6 d after infection. Meanwhile, KEGG analysis indicated that vital pathways related with immunity and reproduction, such as Insulin resistance, FoxO signaling, Lysosome, mTOR signaling, and Toll-like receptor signaling pathways were up-regulated. Among the differentially expressed genes, 22 and 17 were related to immunity and reproduction, respectively, and the expression levels of PPO1 and antimicrobial peptide defensin 3 were increased (log2FC = 5.93 and 6.75, respectively), whereas those of VgA and VgB were reduced (log2FC = −17.82 and −18.13, respectively). These results indicated that that locusts allocate energy and resources to maintain their own survival by increasing immune response when dealing with both immune and reproductive processes. The present study provides the first report of expression levels for genes related with reproduction and immunity in locusts, thereby providing a reference for future studies, as well as theoretical guidance for investigations of locust control.
Angela B. Lange - One of the best experts on this subject based on the ideXlab platform.
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proctolin a possible releasing factor in the corpus cardiacum corpus allatum of the locust
Peptides, 2006Co-Authors: Lisa Clark, J R Zhang, Stephen S. Tobe, Angela B. LangeAbstract:Abstract The corpus cardiacum (CC) and corpus allatum (CA) of the locust, Locusta migratoria , contain intense proctolin-like immunoreactivity (PLI) within processes and varicosities. In contrast, in the cockroach, Diploptera punctata , although a similar staining pattern occurs within the CC, PLI appears absent within the CA. The possible role of proctolin as a releasing factor for adipokinetic hormone (AKH) and juvenile hormone (JH) was investigated in the locust. Proctolin caused a dose-dependent increase in AKH I release (determined by RP-HPLC) from the locust CC over a range of doses with threshold above 10 −8 M and maximal release at about 10 −7 M proctolin. Isolated glandular lobes of the CC released greater amounts of AKH I following treatment with proctolin and in these studies AKH II was also released. Confirmation of AKH I release was obtained by injecting perfusate from incubated CCs into locusts and measuring hemolymph lipid concentration. Perfusate from CC incubated in proctolin contained material with similar biological activity to AKH. Proctolin was also found to significantly increase the synthesis and release of JH from locust CA, with the increase being greatest from CAs that had a relatively low basal rate of JH biosynthesis ( −1 per CA). In contrast, proctolin did not alter the synthesis and release of JH from the cockroach CA. These results suggest that proctolin may act as a releasing factor for AKHs and JH in the locust but does not act as a releasing factor for JH in the cockroach.
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Proctolin: A possible releasing factor in the corpus cardiacum/corpus allatum of the locust.
Peptides, 2005Co-Authors: Lisa Clark, J R Zhang, Stephen S. Tobe, Angela B. LangeAbstract:Abstract The corpus cardiacum (CC) and corpus allatum (CA) of the locust, Locusta migratoria , contain intense proctolin-like immunoreactivity (PLI) within processes and varicosities. In contrast, in the cockroach, Diploptera punctata , although a similar staining pattern occurs within the CC, PLI appears absent within the CA. The possible role of proctolin as a releasing factor for adipokinetic hormone (AKH) and juvenile hormone (JH) was investigated in the locust. Proctolin caused a dose-dependent increase in AKH I release (determined by RP-HPLC) from the locust CC over a range of doses with threshold above 10 −8 M and maximal release at about 10 −7 M proctolin. Isolated glandular lobes of the CC released greater amounts of AKH I following treatment with proctolin and in these studies AKH II was also released. Confirmation of AKH I release was obtained by injecting perfusate from incubated CCs into locusts and measuring hemolymph lipid concentration. Perfusate from CC incubated in proctolin contained material with similar biological activity to AKH. Proctolin was also found to significantly increase the synthesis and release of JH from locust CA, with the increase being greatest from CAs that had a relatively low basal rate of JH biosynthesis ( −1 per CA). In contrast, proctolin did not alter the synthesis and release of JH from the cockroach CA. These results suggest that proctolin may act as a releasing factor for AKHs and JH in the locust but does not act as a releasing factor for JH in the cockroach.
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The association of proctolin with the spermatheca of the locust, Locusta migratoria
Journal of Insect Physiology, 1993Co-Authors: Angela B. LangeAbstract:The association of proctolin or a proctolin-like peptide with the spermatheca of Locusta migratoria has been shown using immunohistochemistry and RP-HPLC coupled to the sensitive locust oviduct bioassay. Immunohistochemistry reveals that a proctolin-like peptide is present in processes and terminal arborizations on the spermatheca, in axons of the nerves which project to the spermatheca and in neurons in the eighth abdominal ganglion. The spermatheca of Locusta is sensitive to proctolin, with exposure to proctolin resulting in dose-dependent increases in muscle tonus as well as increases in amplitude and frequency of phasic contractions. The threshold for proctolin's effect is approximately 10−9 M with a maximum at approximately 5 × 10−8 M. The effects of proctolin on contractions of the spermatheca are reversible. The results indicate that proctolin, or a very similar peptide, is associated with the spermatheca of the locust Locusta migratoria and may play a neural role in modulating muscular activity.
