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The Biological Bulletin Dec 1975
Topics: Animals; Hemolymph; Juvenile Hormones; Larva; Lepidoptera
PubMed: 1203335
DOI: 10.2307/1540383 -
General and Comparative Endocrinology Aug 1989The role of juvenile hormone (JH) in the regulation of prothoracic gland activity was investigated during the early days of the last (fifth) larval instar of Bombyx...
The role of juvenile hormone (JH) in the regulation of prothoracic gland activity was investigated during the early days of the last (fifth) larval instar of Bombyx mori. Allatectomy on the day of larval ecdysis into the fifth instar or 1 day before ecdysis shortened the time between larval ecdysis and gut purge. Prothoracic glands of the freshly ecdysed fifth instar larvae were inactive and did not respond to the prothoracicotropic hormone (PTTH), whereas those larvae that were allatectomized 1 day before ecdysis exhibited secretory activity in vitro and were capable of responding to PTTH. When corpora allata were removed from freshly ecdysed fifth instar larvae, the prothoracic glands became competent to respond to PTTH in 6 hr and exhibited secretory activity in vitro 9 hr after the allatectomy. Treatment of allatectomized larvae with a JH analog resulted in the recovery of the normal inactive state of the glands. These data suggest that JH acts during the early stages of the instar to suppress both the secretory activity of prothoracic glands and also the acquisition of competence to respond to PTTH.
Topics: Animals; Bombyx; Brain; Ecdysterone; Endocrine Glands; Insect Hormones; Juvenile Hormones; Larva; Microinjections; Thorax
PubMed: 2806872
DOI: 10.1016/0016-6480(89)90074-9 -
Journal of Insect Science (Online) 2006Abstract Patterns of juvenile hormone have been intensively studied in the cockroach Blattella germanica under different physiological situations. However, data have...
Abstract Patterns of juvenile hormone have been intensively studied in the cockroach Blattella germanica under different physiological situations. However, data have been mainly obtained in vitro, and refer to hormone synthesized by isolated corpora allata, whereas information available on hormone concentration in the hemolymph is restricted to adult females. In order to complement our studies in vitro, we have measured juvenile hormone titer in the hemolymph of B. germanica females in four characteristic physiological situations: penultimate and last instar nymphs, adults during the first vitellogenic cycle, and adults transporting egg cases (ootheca). In general, a significant positive correlation between rates of hormone synthesis and concentration in the hemolymph is observed. The main disparities appear in the penultimate day of the period of ootheca transport, where titer is high whereas synthesis is low, and on day 6 of the first vitellogenic cycle, where synthesis increases whereas titer decreases. At these stages, the observed disparities between synthesis and titer might be explained by differential action of degradation enzymes.
Topics: Animals; Cockroaches; Female; Juvenile Hormones; Nymph
PubMed: 20233097
DOI: 10.1673/031.006.4301 -
Bioscience, Biotechnology, and... 2013Juvenile hormone (JH) I, II and III in the hemolymph of the silkworm, Bombyx mori were quantified by liquid chromatography-mass spectrometry (LC-MS). JHs were treated...
Juvenile hormone (JH) I, II and III in the hemolymph of the silkworm, Bombyx mori were quantified by liquid chromatography-mass spectrometry (LC-MS). JHs were treated with methanol and trifluoroacetic acid to convert into JH methoxyhydrines (JH-MHs). The key to the analytical condition for JH-MHs was the addition of 5 µM sodium acetate to the eluting solution. Each JH-MH was observed as the sodium adduct ion with good sensitivity. This improved method enabled the titration of JH I, II and III in hemolymph of the silkworm to be monitored from the 3rd instar through to the early pupal stage. A peak of JH I was observed immediately after ecdysis in the 3rd and 4th instar stages. The JH I titer sharply decreased on day 1 and reached the lowest level before ecdysis, but there was no peak at the beginning of the 5th stadium, and no apparent increase was observed until pupation.
Topics: Animals; Bombyx; Chromatography, Liquid; Hemolymph; Hydrogen-Ion Concentration; Juvenile Hormones; Mass Spectrometry; Methanol; Salts
PubMed: 23649254
DOI: 10.1271/bbb.120883 -
PLoS Neglected Tropical Diseases Jan 2015The auto-dissemination approach has been shown effective at treating cryptic refugia that remain unaffected by existing mosquito control methods. This approach relies on...
BACKGROUND
The auto-dissemination approach has been shown effective at treating cryptic refugia that remain unaffected by existing mosquito control methods. This approach relies on adult mosquito behavior to spread larvicide to breeding sites at levels that are lethal to immature mosquitoes. Prior studies demonstrate that 'dissemination stations,' deployed in mosquito-infested areas, can contaminate adult mosquitoes, which subsequently deliver the larvicide to breeding sites. In some situations, however, preventative measures are needed, e.g., to mitigate seasonal population increases. Here we examine a novel approach that combines elements of autocidal and auto-dissemination strategies by releasing artificially reared, male mosquitoes that are contaminated with an insecticide.
METHODOLOGY
Laboratory and field experiments examine for model-predicted impacts of pyriproxyfen (PPF) directly applied to adult male Aedes albopictus, including (1) the ability of PPF-treated males to cross-contaminate females and to (2) deliver PPF to breeding sites.
PRINCIPAL FINDINGS
Similar survivorship was observed in comparisons of PPF-treated and untreated males. Males contaminated both female adults and oviposition containers in field cage tests, at levels that eliminated immature survivorship. Field trials demonstrate an ability of PPF-treated males to transmit lethal doses to introduced oviposition containers, both in the presence and absence of indigenous females. A decline in the Ae. albopictus population was observed following the introduction of PPF-treated males, which was not observed in two untreated field sites.
CONCLUSIONS/SIGNIFICANCE
The results demonstrate that, in cage and open field trials, adult male Ae. albopictus can tolerate PPF and contaminate, either directly or indirectly, adult females and immature breeding sites. The results support additional development of the proposed approach, in which male mosquitoes act as vehicles for insecticide delivery, including exploration of the approach with additional medically important mosquito species. The novelty and importance of this approach is an ability to safely achieve auto-dissemination at levels of intensity that may not be possible with an auto-dissemination approach that is based on indigenous females. Specifically, artificially-reared males can be released and sustained at any density required, so that the potential for impact is limited only by the practical logistics of mosquito rearing and release, rather than natural population densities and the self-limiting impact of an intervention upon them.
Topics: Aedes; Animals; Female; Insecticides; Juvenile Hormones; Male; Mosquito Control; Oviposition; Pyridines
PubMed: 25590626
DOI: 10.1371/journal.pntd.0003406 -
Pesticide Biochemistry and Physiology Dec 2023Allatostatin (AS) or Allatotropin (AT) is a class of insect short neuropeptide F (sNPF) that affects insect growth and development by inhibiting or promote the synthesis...
Allatostatin (AS) or Allatotropin (AT) is a class of insect short neuropeptide F (sNPF) that affects insect growth and development by inhibiting or promote the synthesis of juvenile hormone (JH) in different insects. III-2 is a novel sNPF analog derived from a group of nitroaromatic groups connected by different amino acids. In this study, we found that III-2 showed high insecticidal activity against S. frugiperda larvae with a LC of 18.7 mg L. As demonstrated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), III-2 particularly facilitated JH III and hindered 20E synthesis in S. frugiperda. The results of RNA-Seq and quantitative real-time polymerase chain reaction (qPCR) showed that III-2 treatment promoted the expression of key genes such as SfCYP15C1 in JH synthesis pathway and inhibited the expression of SfCYP314A1 and other genes in the 20E synthetic pathway. Significant differences were also observed in the expression of the genes related to cuticle formation. We report for the first time that sNPF compounds specifically interfere with the synthesis and secretion of a certain JH in insects, thus affecting the ecdysis and growth of insects, and leading to death. This study may provide a new plant conservation concept for us to seek the targeted control of certain insects based on specific interference with different JH.
Topics: Animals; Spodoptera; Chromatography, Liquid; Tandem Mass Spectrometry; Juvenile Hormones; Larva; Insecta
PubMed: 38072528
DOI: 10.1016/j.pestbp.2023.105653 -
General and Comparative Endocrinology May 2009
Topics: Animals; Endocrinology; Genome, Insect; Insecta; Juvenile Hormones; Signal Transduction
PubMed: 19408361
DOI: 10.1016/s0016-6480(09)00157-9 -
The Biological Bulletin Dec 1975
Topics: Animals; Juvenile Hormones; Larva; Lepidoptera
PubMed: 1203337
DOI: 10.2307/1540387 -
The Journal of Biological Chemistry Sep 1995Four nonapeptides that inhibit juvenile hormone synthesis have been isolated by four high performance liquid chromatographic steps from extracts of the brain of the...
Four nonapeptides that inhibit juvenile hormone synthesis have been isolated by four high performance liquid chromatographic steps from extracts of the brain of the field cricket, Gryllus bimaculatus. The primary structures of these peptides were assigned by Edman degradation and mass spectrometry as Gly-Trp-Gln-Asp-Leu-Asn-Gly-Gly-Trp-NH2 (Grb-AST B1), Gly-Trp-Arg-Asp-Leu-Asn-Gly-Gly-Trp-NH2 (Grb-AST B2), Ala-Trp-Arg-Asp-Leu-Ser-Gly-Gly-Trp-NH2 (Grb-AST B3), and Ala-Trp-Glu-Arg-Phe-His-Gly-Ser-Trp-NH2 (Grb-AST B4). Each of the peptides shows high sequence similarity to the locustamyoinhibiting peptide (Lom-MIP), but is structurally different from all the allatostatins so far identified. The synthetic allatostatins Grb-AST B1-4 are potent inhibitors (50% inhibition at 10(-8) to 7 x 10(-8) M) of juvenile hormone III biosynthesis by corpora allata from 3-day-old virgin females of G. bimaculatus using an in vitro bioassay. At 10(-7) M, Grb-AST B1 also strongly inhibits juvenile hormone III biosynthesis by corpora allata from 2-day-old adult males and 1-day-old (males and females) and 4-day-old (females) last instar larvae of G. bimaculatus. The inhibitory effect of Grb-AST B1 was also evident on corpora allata from a related species, Acheta domesticus. Inhibition of juvenile hormone synthesis by Grb-AST B1-4 is reversible.
Topics: Amino Acid Sequence; Animals; Chromatography, High Pressure Liquid; Female; Gryllidae; Juvenile Hormones; Male; Mass Spectrometry; Molecular Sequence Data; Neuropeptides; Sex Factors; Species Specificity
PubMed: 7673141
DOI: 10.1074/jbc.270.36.21103 -
Biochemical Society Transactions Aug 1996
Topics: Animals; Carboxylic Ester Hydrolases; Female; Hemolymph; Juvenile Hormones; Ticks; Tissue Distribution
PubMed: 8878981
DOI: 10.1042/bst024437s