Effects Of Juvenile Hormone Analogue Research Articles

Anti-proliferative and apoptosis-inducing effects of juvenile hormone analogue, fenoxycarb in the Sf21cell line

The apprehension regarding the possible environmental effects of synthetic pesticides has led to the discovery and production of environmental friendly pesticides. Insect hormone mimics, mainly juvenile hormone analogues, like fenoxycarb have acquired attention due to their greater specificity than conventional broad-range insecticides as pest control agents. The study explored the effects of the insecticide juvenile hormone analogue (JHA), fenoxycarb, on the Sf21 cell line of Spodoptera frugiperda to illustrate the mode of action. Cytotoxicity assay was conducted at different concentrations of fenoxycarb ranging from 0.5 nM to 10 μM. The results showed the concentration-and time-dependent anti-proliferative effect of fenoxycarb. The median inhibitory concentration (IC50) was calculated as 28 nM at 48 h of exposure, and IC50 and IC25 concentrations were used for further cytotoxicity screening assays. Furthermore, the significant morphological changes of the cells after 48 h revealed the development of apoptotic bodies, membrane blebbing, cell size reduction, and irregular cell aggregation; additionally, enlarged cell spaces and widely diffused apoptotic bodies were observed after 72 h of insecticide exposure. In the confocal microscopic analysis of fenoxycarb treated cells, the nucleus was observed to condense and collapse into many fragments by Hoechst-33,342. Assessment of the relative potential of the cell cycle at two concentrations (IC50& IC25) reported the concentration-and time-dependent reduction of cells in the G1 phase with an upsurge in apoptotic cells. The percentage of cells that underwent apoptotic changes, such as loss of mitochondrial membrane potential (MMP), was strictly dependent on the fenoxycarb concentration and duration of exposure. The findings confirm the presence of fenoxycarb-mediated cell proliferation inhibition and apoptosis in Sf21 cell lines.

Apoptotic and autophagic characteristics of perivisceral fat body remodeling of the greater wax moth Galleria mellonella and effects of juvenile hormone analog, fenoxycarb, on these processes.

In holometabolous insects, many tissues and organs such as the fat body and midgut undergo a remodeling process during metamorphosis. Larval fat body cells are eliminated by programmed cell death (PCD), while tissue cells that adapt to adult life are formed by stem cells. In this study, we analyzed the features of the remodeling period of Galleria mellonella fat body in terms of PCD types, apoptotic and autophagic cell death characteristics. Besides, the effects of juvenile hormone (JH) on these processes were evaluated under the modified hormonal conditions via applications of JH analog, fenoxycarb. Several hallmarks of apoptotic and autophagic cell death were analyzed by morphological, biochemical, and molecular methods. The results of the present study have ascertained that the degeneration process of larval cells occurs via autophagic cell death accompanied by caspase-3 activity during the pupal period and it is regulated by 20-hydroxyecdysone (20HE) mediated by ecdysone receptor B1 (EcR-B1). Increased activity of the acid phosphatase and upregulation of ATG6 and ATG8 in parallel with the formation of autophagosomes in the fat body of Galleria during the pupal period strongly indicated that autophagy was the key player in the remodeling processes.

Response variability of juvenile hormone and juvenile hormone analogs in workers of the Formosan subterranean termite (Coptotermes formosanus Shiraki)

Abstract Juvenile hormone (JH) or juvenile hormone analog (JHA) can induce soldier formation in termites. However, different studies have yielded inconsistent results on the effects of JHA on soldier production in Coptotermes formosanus Shiraki. Using filter paper as the testing substrate, the effects of JH III, pyriproxyfen and methoprene on the intact filter paper left, worker mortality and presoldier formation were tested on six colonies. Our results showed that pyriproxyfen and methoprene were more repellent than JH III. No significant difference in toxicity was observed among methoprene, pyriproxyfen and JH III. JH III and pyriproxyfen did not cause workers to differentiate into presoldiers, but methoprene can induce formation of presoldiers. Colony response variability to methoprene was observed. The confirmation of the effects of JH/JHA on C. formosanus establishes the foundation for molecular studies of soldier differentiation in this species.

Juvenile hormone regulates the shift from migrants to residents in adult oriental armyworm, Mythimna separata

In migratory insects, increasing evidence has demonstrated juvenile hormone (JH) is involved in regulating adult reproduction and flight. Our previous study demonstrated that the switch from migrants to residents in Mythimna separata could be induced by adverse environmental conditions during a sensitive period in adulthood (the first day post-emergence), but the role of JH in this switch is not clear. Here, we found a significantly different pattern of JH titers between migrants and residents, with migrants showing a slower release of JH during adulthood than residents. Application of JH analogue (JHA) in the 1-day-old adults, significantly accelerated adult reproduction and suppressed flight capacity. The pre-oviposition period and period of first oviposition of migrants treated with JHA were significantly shorter, while the total lifetime fecundity and mating percentage increased. The flight capacity and dorso-longitudinal muscle size of the migrants were decreased significantly when treated with JHA. The effect of JHA on reproduction and flight capacity indicate that JH titers during the sensitive period (first day post-emergence) regulates the shift from migrants to residents in M. separata.

Effects of juvenile hormone analogue (methoprene) and 20-hydroxyecdysone on reproduction in Polygonia c-aureum (Lepidoptera: Nymphalidae) in relation to adult diapause.

We investigated the effects of juvenile hormone analogue (methoprene) and 20-hydroxyecdysone on female and male reproduction in a nymphalid butterfly, Polygonia c-aureum. This butterfly has a facultative adult diapause controlled by the corpora allata and brain. Methoprene seems to terminate reproductive diapause, although transplantation experiments indicate that the activity of the corpora allata does not affect male mating behavior Endo (Dev Growth Differ 15:1-10, 1973a), suggesting that the brain may be involved in diapause. We found that exposure to methoprene promoted the development of ovaries and of the male accessory glands and simplex. On the other hand, exposure to 20-hydroxyecdysone did not promote the development of female and male reproductive organs and eupyrene sperm movement from the testis to the duplex in the adult stage. Ecdysteroid titer in both sexes was consistently low in adults. These results suggest that imaginal diapause is largely regulated by juvenile hormone in this butterfly.

Effects of juvenile hormone analogue and ecdysteroid on adult eclosion of the fruit fly Bactrocera minax (Diptera: Tephritidae).

The univoltine Bactrocera minax (Enderlein) is a devastating pest of citrus in Nepal, India, Bhutan, and China. To better understand the overwintering pupal diapause, we investigated the juvenile hormone III (JH III) and ecdysteroid 20-hydroxyecdysone (20E) titers across the developmental stages, and the effects of juvenile hormone analog (JHA) and 20E treatments on adult emergence patterns. The results showed that both JH III and 20E levels fluctuated from the late larval stage to the late pupal stage. JHA and 20E treatments at the late larval stage had marginal effect on the adult emergence patterns, with slightly faster adult eclosion and higher eclosion rate. Similarly, JHA treatment at the early pupal stage did not affect the adult emergence. However, 20E treatment at the early pupal stage remarkably shortened the duration of diapause, but lowered the eclosion rate, especially with relatively high dose. These findings demonstrated that 20E treatment at the early pupal stage is a suitable method to hasten the diapause termination of B. minax, which will contribute to the rearing of B. minax in the laboratory as needed for routine experiments.

Effects of juvenile hormone analog on physiological and behavioral maturation in honeybee drones

The functions of juvenile hormone in the physiological and behavioral maturation in Apis mellifera males (drones) were investigated by application of a juvenile hormone analog, methoprene. No evidence was found for the stimulation of maturation of male reproductive organs by methoprene. The dry weight of the seminal vesicle and reproductive accessory gland was slightly but significantly lighter in drones treated with a high dose (100 or 500 μg/male) of methoprene than drones treated either with a low dose (1 or 10 μg/male) or solvent control only. Methoprene accelerated in-colony male movement from the center to the periphery. It also induced earlier diet transition from pollen and jelly-like materials to honey. These results suggest that juvenile hormone acts as a behavioral pacemaker rather than as a gonadotropin in drones.

호박벌의 휴면 제어 관련 유전자 탐색 및 특성 분석

To find diapause-related genes, we were performed by differential hybridization with three types of [α32 P]dCTP-labeled total cDNA probes synthesized from diapause-prepared, diapause-maintained and diapause-activated stage of Bombus ignitus queen. Nine individual cDNA clones were found to be differentially expressed in diapause-maintained and diapause-activated stage. Among these clones, BIDC9(BIDC ; Bombus ignitus differentially expressed clone) was analyzed through full-length sequencing and expression pattern analysis. This clone was specifically expressed in the thorax organ. The effect of Juvenile hormone analog(JHA) and CO2 treatment was examined. JHA treatment induced the expression of BIDC9 cDNA clone abruptly after 4 day of treatment. CO2 treatment induced also the clone after 2 day of treatment. BIDC9 cDNA was identified as Bombus ignitus diapause gene contained an open reading frame of 1376 bp encoding 255 amino acids.

Programmed cell death of larval tissues induced by juvenile hormone in the bamboo borer, Omphisa fuscidentalis

Programmed cell death (PCD) plays a critical role during animal development through the destruction of unneeded cells and tissues. In some insects, the prothoracic glands (PGs) and anterior silk glands (ASGs) are larval-specific tissues that are normally eliminated by PCD after pupation. Previous studies report that juvenile hormone analog (JHA) terminates the larval diapause of Omphisa fuscidentalis by increasing the hemolymph ecdysteroids that trigger PCD. Because JHA may indirectly induce the PCD of the PGs and ASGs of Omphisa diapausing larvae, the effects of JHA on the induction of PCD were determined. The application of 1μg JHA induced PCD in the PGs and ASGs of larvae identified as stage G0 (prior to pupation). The injection of 1μg 20E triggered the PCD of the ASGs when the larvae expressed a G0–G1 morphology, whereas PCD occurred in the PGs on day 1 post-injection. Histological studies revealed similar patterns of morphological changes during the PG and ASG PCD in the JHA- and 20E-treated larvae. Furthermore, to confirm that PCD was induced by a high ecdysteroid level that increases after JHA application, the expression profiles of EcR-A and EcR-B1 in the PGs and ASGs from the JHA-treated larvae were examined, and the results showed that the expression levels of EcR-A and EcR-B1 mRNA increased during the G0 stage. These results suggest that JHA may be involved in PCD by increasing the ecdysteroid titer, leading to termination of the larval diapause period in Omphisa fuscidentalis.

Effect of juvenile hormone analog in a natural host-parasite system

Hormones mediate the physiological responses of animals to environmental changes. Consequently, hormones can be responsible of trade offs between different life history traits. Juvenile hormone (JH) is thought to mediate resource allocation in insects: specifically, it is thought to enhance the expression of condition-related traits like sexual signals, whilst reducing immune responsiveness. Here, we experimentally test whether a JH analog (JHa) had an effect on immunity of male dragonflies Celithemis eponina, and if such effects are translated into faster growth or development of a natural parasite (water mite). We also tested the effects of JHa on host condition (muscular mass and fat reserves) of mature male dragonflies. Mites from JHa treated dragonflies grew faster than mites from control dragonflies receiving just an acetone carrier. However, there was no effect of JHa on measures of host immune response (melanization of a nylon implant) or condition of mature males. We suggest that better parasite growth in JHa treated males does not result from the JH immunosuppressive function, but instead it appears that parasites receive hormone signals from the host and alter their development without affecting host condition measurably. Our work highlights the importance of measuring both immune parameters and response to real parasites when studying evolutionary trade offs.

In vitro effects of juvenile hormone analog on wing disc morphogenesis under ecdysteroid treatment in the female-wingless bagworm moth Eumeta variegata (Insecta: Lepidoptera, Psychidae)

Female adults of the bagworm moth, Eumeta variegata, lack wings completely, whereas male adults of this species have functional wings. We previously found that ecdysteroid induces apoptotic events in the female wing rudiment of E. variegata in vitro, whereas the male wing discs cultured with 20-hydroxyecdysone (20E) underwent apolysis and then cell differentiation. To investigate whether juvenile hormone (JH) in involved in sex-specific cellular response to ecdysteroid during wing development between sexes of E. variegata, we tested the effects of juvenile hormone analog (JHA), methoprene, and 20E on wing disc morphogenesis between sexes in vitro. Using transmission electron microscopy (TEM), we found that both higher concentration of JHA (5 μg/ml) and 20E (1 μg/ml) addition induced cell death (apoptosis) in the male wing discs but not induced cell death in the female wing rudiments in vitro in E. variegata. These culture experiments clearly detected the differential responses of wing discs to JHA under ecdysteroid treatment between sexes. We propose two important hypotheses: (1) JH is not significantly involved in the suppression of the female wing rudiment morphogenesis under 20E treatment, (2) female wing rudiment has lost the ability for cell proliferation in response to the stimulus of 20E.

Effect of an insect juvenile hormone analogue, Fenoxycarb ® on development and oxygen uptake by larval lobsters Homarus gammarus (L.)

Little attention has been focused on the effect of anthropogenic compounds that disrupt the endocrine systems in crustaceans. Consequently, this study investigated the effects of the juvenile hormone analogue (JHA), Fenoxycarb ® on selected physiological and developmental processes of the zoeal stages in the European lobster, Homarus gammarus. Chronic exposure to Fenoxycarb (50μg L − 1) resulted in a significant ( p < 0.05) reduction in moult frequency and size at moult. Fenoxycarb exposure extended zoeal duration between zoea I to II ( p < 0.05) and resulted in total inhibition of the moult from zoea II to III. Significantly greater rates of O 2 uptake were observed in Fenoxycarb-exposed larvae in comparison with controls ( p < 0.05). All rates of O 2 uptake decreased significantly between 7 and 12d of exposure ( p < 0.05). At 12d, exposure to the solvent control no longer influenced rates of O 2 uptake, but it was not possible to attribute increased O 2 uptake to Fenoxycarb exposure directly, as treated individuals did not moult beyond zoea III. The low exposure concentrations of Fenoxycarb, comparable to those used in plant protection, resulted in endocrine disrupted responses in H. gammarus (albeit with little clear, demonstrable effect on metabolism) a finding that could have important ecological and commercial implications.

Functional analysis of the larval serum protein gene promoter from silkworm, Bombyx mori.

The regulation region of larval serum protein gene, Bombyx mori. (BmLSP), consisting of the first intron, the first exon, the central promoter region and 5’-upstream region, is cloned from genomic DNA from the silkworm variety of Suju × Minghu. Using PCR and restriction endonuclease methods, a series of luciferase reporter plasmids, driven by different length of BmLSP promoters, are constructed. Via the transient expression system in BmN cells, the effects of the regulation elements and foreign insect hormones on the BmLSP promoter activity are investigated. The results demonstrate that the promoter activity of BmLSP is 5.8- or 4.4-fold higher than that of BmLSPs whose first intron or the element in 5’-upstream region harboring the homologous sequence with the first intron of light-chain fibroin gene (EHIF) is deleted, respectively, suggesting that both the first intron and EHIF contain the main positive cis-acting elements. However, the inactive mariner transposable element (MTE) in 5 ’-upstream region presents a negative effect. Furthermore, the effects of juvenile hormone analogue (JHA) on the BmLSP promoter activity show a typical dose-dependent manner, that is, low concentration treatments increase the BmLSP promoter activity and high concentration treatments decrease it. Meanwhile, insect ecdysone (MH) treatments present no significant effect.

成虫生殖休眠中のウヅキイエバエモドキ, Melinda pusilla の卵発達に対する幼若ホルモン様物質の影響

成虫生殖休眠中のウヅキイエバエモドキ, Melinda pusilla の卵発達に対する幼若ホルモン様物質の影響

Vitellogenesis in a lady-beetle, Coccinella septempunctata in relation to the aestivation-diapause

Yolk-protein precursor, vitellogenin, synthesis and effects of juvenile hormone analogue on vitellogenesis were studied in a lady-beetle, Coccinella septempunctata, which enters aestivation-diapause in the adult stage. In the prediapause period, total protein synthesis in the fat body was relatively high but vitellogenin synthesis was negligible. During diapause, total protein synthesis declined to a low level (but detectable) and vitellogenin synthesis was not detected at all. In the course of diapause termination, total protein synthesis recovered gradually, but vitellogenin synthesis did not occur before feeding. Juvenile hormone analogue application to a diapausing female induces vitellogenin synthesis and consequent oviposition. Sensitivities to juvenile hormone analogue in the stimulation of vitellogenin synthesis depended on the stage of diapause: pre-diapause period, diapause period and post-diapause period. The time lags between juvenile hormone analogue application and vitellogenin induction in the haemolymph were shorter in the pre- and post-diapause period than that in diapausing females.

Effects of juvenile hormone analogue on ecdysis prevention induced by precocene in Rhodnius prolixus (Hemiptera:Reduviidae).

Precocene II, added to the meal of fourth-instar larvae of Rhodnius prolixus (25 micrograms/ml of blood), induced an increase in the duration of the molting cycle. This effect was related to the decrease of both the nuclear area of the prothoracic gland cells and the mitotic activity in epidermal cells. Juvenile hormone analogue applied topically (60 micrograms/insect) together with Precocene II treatment avoided atrophy of the prothoracic glands and induced a higher number of epidermal mitosis accelerating the time of subsequent ecdysis. A possible relationship between juvenile hormone and production of ecdysone is discussed.

Field and laboratory tests on the effect of juvenile hormone analogue on the larvae of Galleria mellonella L. (Lep., Pyralidae)

AbstractThe greater wax moth, Galleria mellonella, was tested for mortality of larvae, adult emergence and some morphological responses under normal conditions and following exposure to Altosid SR‐10 (ZR515) in laboratory and apiary. Water solutions of Altosid SR‐10 (isopropyl [2E, 4E]‐11‐methoxy‐3,7,11‐trimethyl‐2,4 dodecadionate) were used for dipping of G. mellonella larvae for 5 seconds, in laboratory. Percent larval mortality, one week after treatment, was ranged from 5.0 to 8.6 % at 31.25 ppm to 500 ppm of Altosid. Percent malformed adults, five weeks after treatment, was ranged from 1.7 to 20.0 % at 31.25 ppm to 500 ppm of Altosid. The dose expected to produce 50 % inhibition of normal adult emergence (ED50) was 400 ppm of Altosid. Field treatment of G. mellonella in the apiary inside the honey bee colonies using musclin‐cloth pieces which previously dipped in water solutions of Altosid, indicated that a dosage of 1500 ppm caused complete inhibition of normal adult emergence of G. mellonella accompanied with 36 % increase on brood rearing ability of treated colonies as compared with control ones.ZusammenfassungFreiland‐ und Laborversuche zur Wirkung von JHA auf die Raupen von Galleria mellonella L. (Lep., Pyralidae)Die Große Wachsmotte, Galleria mellonella, wurde hinsichtlich Raupenmortalität, Falterschlüpfen und einiger morphologischer Merkmale unter der Wirkung normaler Verhältnisse sowie des JHA Altosid SR‐10 im Labor und in Bienenstöcken untersucht. Im Labor wurden die Raupen 5 s in wäßrige Lösungen von Altosid getaucht. Die Raupenmortalität betrug eine Woche nach Behandlung zwischen 5,0 und 8,6 % bei Altosid‐Dosen zwischen 31,25 und 500 ppm. 5 Wochen nach Behandlung wurden 1,7 bis 20,0% deformierter geschlüpfter Falter bei 31,25–500 ppm Altosid festgestellt. Die zu 50%iger Deformierung führende Altosid‐Dosis betrug 400 ppm. In Bienenstöcken aufgehängte Stücke von Musselingewebe, die mit Altosid getränkt waren, führten bei einer Dosis von 1500 ppm zu vollständiger Verhinderung des normalen Falterschlüpf ens der Wachsmotte, was einen im Mittel 36%igen Anstieg des Brutumfangs des Bienenvolkes zur Folge hatte.