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Development (Cambridge, England) May 2023Female insects can enter reproductive diapause, a state of suspended egg development, to conserve energy under adverse environments. In many insects, including the fruit...
Female insects can enter reproductive diapause, a state of suspended egg development, to conserve energy under adverse environments. In many insects, including the fruit fly, Drosophila melanogaster, reproductive diapause, also frequently called reproductive dormancy, is induced under low-temperature and short-day conditions by the downregulation of juvenile hormone (JH) biosynthesis in the corpus allatum (CA). In this study, we demonstrate that neuropeptide Diuretic hormone 31 (DH31) produced by brain neurons that project into the CA plays an essential role in regulating reproductive dormancy by suppressing JH biosynthesis in adult D. melanogaster. The CA expresses the gene encoding the DH31 receptor, which is required for DH31-triggered elevation of intracellular cAMP in the CA. Knocking down Dh31 in these CA-projecting neurons or DH31 receptor in the CA suppresses the decrease of JH titer, normally observed under dormancy-inducing conditions, leading to abnormal yolk accumulation in the ovaries. Our findings provide the first molecular genetic evidence demonstrating that CA-projecting peptidergic neurons play an essential role in regulating reproductive dormancy by suppressing JH biosynthesis.
Topics: Animals; Female; Corpora Allata; Drosophila melanogaster; Juvenile Hormones; Neurons; Insect Hormones; Drosophila Proteins; Reproduction
PubMed: 37218457
DOI: 10.1242/dev.201186 -
Biomolecules Nov 2023Honey bees are typical model organisms for the study of caste differentiation, and the juvenile hormone (JH) is a crucial link in the regulatory network of caste...
Honey bees are typical model organisms for the study of caste differentiation, and the juvenile hormone (JH) is a crucial link in the regulatory network of caste differentiation in honey bees. To investigate the mechanism of JH-mediated caste differentiation, we analyzed the effect of the JH response gene on this process. We observed that expression levels were significantly higher in queen larvae than in worker larvae at the 48 h, 84 h, and 120 h larval stages, and were regulated by JH. Inhibiting expression in honey bee larvae using RNAi could lead to the development of larvae toward workers. We also analyzed the transcriptome changes in honey bee larvae after RNAi and identified 191 differentially expressed genes (DEGs) and 682 differentially expressed alternative splicing events (DEASEs); of these, many were related to honey bee caste differentiation. Our results indicate that regulates caste differentiation in honey bees by acting as a JH-responsive gene.
Topics: Bees; Animals; Juvenile Hormones; Larva; Transcriptome
PubMed: 38002339
DOI: 10.3390/biom13111657 -
Frontiers in Immunology 2022Cry toxins produced by (Bt) are well known for their insecticidal activities against Lepidopteran, Dipteran, and Coleopteran species. In our previous work, we showed...
Cry toxins produced by (Bt) are well known for their insecticidal activities against Lepidopteran, Dipteran, and Coleopteran species. In our previous work, we showed that trypsin-digested full-length Cry7Ab4 protoxin did not have insecticidal activity against larvae but strongly inhibited their growth. In this paper, we expressed and purified recombinant active Cry7Ab4 toxic core from for bioassay and identified its binding proteins. Interestingly, Cry7Ab4 toxic core exhibited activity to delay the pupation of larvae. Using protein pull-down assay, several proteins, including basic juvenile hormone-suppressible protein 1-like (BJSP-1), were identified from the midgut juice of larvae as putative Cry7Ab4-binding proteins. We showed that feeding larval Cry7Ab4 toxic core upregulated the level of BJSP-1 mRNA in the hemocytes and fat body and decreased the free juvenile hormone (JH) level in larvae. BJSP-1 interacted with Cry7Ab4 and bound to free JH . A possible mechanism of Cry7Ab4 in delaying the pupation of larvae was proposed.
Topics: Animals; Bacterial Proteins; Insect Proteins; Insecticides; Juvenile Hormones; Larva; Moths; RNA, Messenger; Trypsin
PubMed: 36159828
DOI: 10.3389/fimmu.2022.849620 -
BMC Biology Dec 2022In insects, an interplay between the activities of distinct hormones, such as juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulates the progression through...
BACKGROUND
In insects, an interplay between the activities of distinct hormones, such as juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulates the progression through numerous life history hallmarks. As a crucial endocrine factor, JH is mainly synthesized in the corpora allata (CA) to regulate multiple physiological and developmental processes, including molting, metamorphosis, and reproduction. During the last century, significant progress has been achieved in elucidating the JH signal transduction pathway, while less progress has been made in dissecting the regulatory mechanism of JH biosynthesis. Previous work has shown that receptor tyrosine kinase (RTK) signaling regulates hormone biosynthesis in both insects and mammals. Here, we performed a systematic RNA interference (RNAi) screening to identify RTKs involved in regulating JH biosynthesis in the CA of adult Blattella germanica females.
RESULTS
We found that the epidermal growth factor receptor (Egfr) is required for promoting JH biosynthesis in the CA of adult females. The Egf ligands Vein and Spitz activate Egfr, followed by Ras/Raf/ERK signaling, and finally activation of the downstream transcription factor Pointed (Pnt). Importantly, Pnt induces the transcriptional expression of two key enzyme-encoding genes in the JH biosynthesis pathway: juvenile hormone acid methyltransferase (JHAMT) and methyl farnesoate epoxidase (CYP15A1). Dual-luciferase reporter assay shows that Pnt is able to activate a promoter region of Jhamt. In addition, electrophoretic mobility shift assay confirms that Pnt directly binds to the - 941~ - 886 nt region of the Jhamt promoter.
CONCLUSIONS
This study reveals the detailed molecular mechanism of Egfr signaling in promoting JH biosynthesis in the German cockroach, shedding light on the intricate regulation of JH biosynthesis during insect development.
Topics: Animals; Female; Blattellidae; Corpora Allata; Juvenile Hormones; Metamorphosis, Biological; Signal Transduction; Mammals
PubMed: 36514097
DOI: 10.1186/s12915-022-01484-z -
International Journal of Molecular... Jan 2022Juvenile hormone and ecdysone are key regulators in the metamorphosis and development. Grocho (Gro) is a highly conserved protein required for metamorphosis and...
Juvenile hormone and ecdysone are key regulators in the metamorphosis and development. Grocho (Gro) is a highly conserved protein required for metamorphosis and development. Brown planthopper () is a major pest affecting rice production in China and many Asian countries. Although the molecular function of has been investigated in holometabolous insects such as and , their role in the hemimetabolous insect, brown planthopper, and the relationship between / and JH/ecdysone signaling pathway, remained unknown. In this study, () and () were cloned. An analysis of the predicted protein sequence showed that NlGro has highly conserved Q domain and WD40 domain, and NlGro1-L has a highly conserved WD40 domain. The expression profiles of both genes were studied by quantitative real-time PCR (qRT-PCR). Their relative expressions were high in egg, head, wing, ovary, and testis. and were found to interact genetically with juvenile hormone and ecdysone signaling by hormone treatment and RNAi of JH/ecdysone signaling-related genes. Moreover, when or was down-regulated alone, the survival rate was decreased, the ovarian development was delayed, and the oviposition was also affected. All defects were aggravated when and were down-regulated together. This study will help to develop new pesticides on the basis of the function of and , and provide new possibilities for the control of .
Topics: Amino Acid Sequence; Animals; Basic Helix-Loop-Helix Transcription Factors; Female; Gene Expression Regulation, Developmental; Hemiptera; Insect Proteins; Juvenile Hormones; Metamorphosis, Biological; Ovary; Oviposition; Sequence Homology; Wings, Animal
PubMed: 35163119
DOI: 10.3390/ijms23031197 -
Scientific Reports Mar 2019Zika virus infection and dengue and chikungunya fevers are emerging viral diseases that have become public health threats. Their aetiologic agents are transmitted by the...
Zika virus infection and dengue and chikungunya fevers are emerging viral diseases that have become public health threats. Their aetiologic agents are transmitted by the bite of genus Aedes mosquitoes. Without effective therapies or vaccines, vector control is the main strategy for preventing the spread of these diseases. Increased insecticide resistance calls for biorational actions focused on control of the target vector population. The chitin required for larval survival structures is a good target for biorational control. Chitin synthases A and B (CHS) are enzymes in the chitin synthesis pathway. Double-stranded RNA (dsRNA)-mediated gene silencing (RNAi) achieves specific knockdown of target proteins. Our goal in this work, a new proposed RNAi-based bioinsecticide, was developed as a potential strategy for mosquito population control. DsRNA molecules that target five different regions in the CHSA and B transcript sequences were produced in vitro and in vivo through expression in E. coli HT115 and tested by direct addition to larval breeding water. Mature and immature larvae treated with dsRNA targeting CHS catalytic sites showed significantly decreased viability associated with a reduction in CHS transcript levels. The few larval and adult survivors displayed an altered morphology and chitin content. In association with diflubenzuron, this bioinsecticide exhibited insecticidal adjuvant properties.
Topics: Aedes; Animals; Chikungunya Fever; Chitin Synthase; Dengue; Diflubenzuron; Escherichia coli; Gene Silencing; Insecticides; Larva; Mosquito Vectors; Zika Virus Infection
PubMed: 30858430
DOI: 10.1038/s41598-019-39666-5 -
Changes in sex differences in neuroanatomical structure and cognitive behavior across the life span.Learning & Memory (Cold Spring Harbor,... Sep 2022Sex differences occur in the structure and function of the rat cerebral cortex and hippocampus, which can change from the juvenile period through old age. Although the...
Sex differences occur in the structure and function of the rat cerebral cortex and hippocampus, which can change from the juvenile period through old age. Although the evidence is incomplete, it appears that in at least some portions of the cortex these differences develop due to the rise of ovarian hormones at puberty and are potentially not dependent on the perinatal rise in testosterone, which is essential for sexual differentiation of the hypothalamus and sexual behavior. During aging of female rats, the presence of continued ovarian hormone secretion after cessation of the estrous cycle also influences sex differences in neuroanatomical structure and cognitive behavior, resulting in nullification or reversal of sex differences seen in younger adults. Sex differences can be altered by experience in a stimulating environment during the juvenile/adolescent period, and sex differences in performance even can be affected by the parameters of a task. Thus, broad generalizations about differences such as "spatial ability" are to be avoided. It is clear that to understand how the brain produces behavior, sex and hormones have to be taken into account.
Topics: Animals; Cognition; Female; Longevity; Male; Rats; Sex Characteristics; Sex Differentiation; Testosterone
PubMed: 36206396
DOI: 10.1101/lm.053499.121 -
Ecotoxicology and Environmental Safety May 2017Some pesticides are applied directly to aquatic systems to reduce numbers of mosquito larvae (larvicides) and thereby reduce transmission of pathogens that mosquitoes... (Review)
Review
Some pesticides are applied directly to aquatic systems to reduce numbers of mosquito larvae (larvicides) and thereby reduce transmission of pathogens that mosquitoes vector to humans and wildlife. Sustained, environmentally-safe control of larval mosquitoes is particularly needed for highly productive waters (e.g., catchment basins, water treatment facilities, septic systems), but also for other habitats to maintain control and reduce inspection costs. Common biorational pesticides include the insect juvenile hormone mimic methoprene and pesticides derived from the bacteria Bacillus thuringiensis israelensis, Lysinibacillus sphaericus and Saccharopolyspora spinosa (spinosad). Health agencies, the public and environmental groups have especially debated the use of methoprene because some studies have shown toxic effects on non-target organisms. However, many studies have demonstrated its apparent environmental safety. This review critically evaluates studies pertinent to the environmental safety of using methoprene to control mosquito larvae, and provides concise assessments of the bacterial larvicides that provide sustained control of mosquitoes. The review first outlines the ecological and health effects of mosquitoes, and distinguishes between laboratory toxicity and environmental effects. The article then interprets non-target toxicity findings in light of measured environmental concentrations of methoprene (as used in mosquito control) and field studies of its non-target effects. The final section evaluates information on newer formulations of bacterially-derived pesticides for sustained mosquito control. Results show that realized environmental concentrations of methoprene were usually 2-5µg/kg (range 2-45µg/kg) and that its motility is limited. These levels were not toxic to the vast majority of vertebrates and invertebrates tested in laboratories, except for a few species of zooplankton, larval stages of some other crustaceans, and small Diptera. Studies in natural habitats have not documented population reductions except in small Diptera. Bacterial larvicides showed good results for sustained control with similarly limited environmental effects, except for spinosad, which had broader effects on insects in mesocosms and temporary pools. These findings should be useful to a variety of stakeholders in informing decisions on larvicide use to protect public and environmental health in a 'One Health' framework.
Topics: Animals; Bacillaceae; Bacillus thuringiensis; Culicidae; Diptera; Drug Combinations; Environmental Health; Insecticides; Larva; Macrolides; Methoprene; Mosquito Control; Water Pollutants
PubMed: 28187397
DOI: 10.1016/j.ecoenv.2016.12.038 -
International Journal of Molecular... Mar 2022Allatostatin C (PISCF/AST) is a neuropeptide gene that affects juvenile hormone (JH) synthesis in the corpora allata. Juvenile hormone acid O-methyltransferase () is a...
Allatostatin C (PISCF/AST) is a neuropeptide gene that affects juvenile hormone (JH) synthesis in the corpora allata. Juvenile hormone acid O-methyltransferase () is a key gene in the JH biosynthetic pathway. In this study, two genes encoding and were cloned. Both and were expressed in the larvae, pupae and adults of Chinese white pine beetle (), and highly expressed in the head and the gut. The expression of the two genes was induced by JH analog (JHA) methoprene and the functions of the two genes were then investigated by RNAi. Considering the role of hormones in metamorphosis, JHA significantly induced and in the larval stage. knockdown in larvae, pupae and adults significantly increased the mRNA levels. Moreover, knockdown of instead of increased pupae mortality and the abnormal rate of emergence morphology and reduced emergence rates. However, knockdown of instead of significantly reduced frontalin biosynthesis in adult males. The results showed that acts as an allatostatin and inhibits JH biosynthesis, and that is a key regulatory enzyme for JH synthesis in the .
Topics: Animals; Corpora Allata; Juvenile Hormones; Larva; Male; Methyltransferases; Neuropeptides; Pupa
PubMed: 35269892
DOI: 10.3390/ijms23052749 -
Psychopharmacology Oct 2019Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurobehavioural disorders with morphological and functional brain abnormalities. However,...
RATIONALE
Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurobehavioural disorders with morphological and functional brain abnormalities. However, there is a growing body of evidence that abnormalities in the immune and endocrine systems may also account for the ADHD pathogenesis.
OBJECTIVES
To test ADHD pathogenesis in neurological, immune and endocrine systems, this study examined the concentrations of cytokines, chemokines, oxidative stress markers, metabolic parameters, steroid hormones and steroidogenic enzymes in the serum and/or tissues of spontaneously hypertensive rats (SHRs, animal model of ADHD) and Wistar Kyoto rats (WKYs, control animals). Moreover, the volume of the medial prefrontal cortex (mPFC) as well as the density of dopamine 2 (D) receptor-expressing cells and tyrosine hydroxylase (TH)-positive nerve fibres in it was also elucidated.
METHODS
Peripheral blood, spleen and adrenal gland samples, as well as brain sections collected on day 35 (juvenile) and day 70 (maturating) from SHRs and WKYs, were processed by ELISA and immunohistochemistry, respectively.
RESULTS
The results show significant increases of serum and/or tissue concentrations of cytokines, chemokines and oxidative stress markers in juvenile SHRs when compared to the age-matched WKYs. These increases were accompanied by a lowered volume of the mPFC and up-regulation of D in this brain region. In maturating SHRs, the levels of inflammatory and oxidative stress markers were normalised and accompanied by elevated contents of steroid hormones.
CONCLUSIONS
Significant elevations of serum and/or tissue contents of cytokines, chemokines and oxidative stress markers as well as volumetric and neurochemical alterations in the mPFC of juvenile SHRs may suggest the cooperation of neurological and immune systems in the ADHD pathogenesis. Elevated levels of steroid hormones in maturating SHRs may be a compensatory effect involved in reducing inflammation and ADHD symptoms.
Topics: Animals; Attention Deficit Disorder with Hyperactivity; Brain; Chemokines; Cytokines; Disease Models, Animal; Dopamine; Endocrine System; Immune System; Inflammation Mediators; Male; Nervous System; Oxidative Stress; Prefrontal Cortex; Rats; Rats, Inbred SHR; Rats, Inbred WKY
PubMed: 30737597
DOI: 10.1007/s00213-019-5180-0