EFFECT OF ABSCISIC ACID ON VITELLOGENESIS IN SARCOPHAGA BULLATA

Abstract

In the carnivorous dipteran Sarcophaga bullata Parker, vitellogenesis was partially inhibited by injection of two doses of 12 μg abscisic acid (ABA), There was no significant difference between injections on day 2 and 4, or on day 4 and 6. Higher and lower doses were less effective, The mixture of isomers inhibited vitellogenesis more than the cis‐trans isomer. ABA had no effect on the total lipid concentration of the haemolymph but it inhibited the sharp increase in total protein concentration of the haemolymph and particularly that of vitellogenin, which normally occurred within 24 hr following liver feeding on day 4, Since vitellogenin synthesis is under the control of moulting hormone (MH), the MH activity was measured by radioimmunoassay to find out whether ABA might interact with vitellogenin synthesis via its hormonal inductor. Eight hours after liver feeding, there was a MH peak in the control groups while following ABA treatment this peak occurred after 18 hr, The inhibitory effect of ABA on vitellogenesis could be overruled by feeding sugar impregnated with ecdysterone (5 mg/g), not by topical application of JH. Our results suggest that ABA might interact with a mechanism which phytophagous and non‐phytophagous insects share in common. If in phytophagous insects the same amount of ABA per gram weight, as was effective in Sarcophaga (about 200 μg/g), is needed to reduce fecundity, it is not probable that this plant hormone plays a role in the seasonal synchronisation of the growth and reproduction of insects with the senescence of their host plants. RÉSUMÉ EFFET DE L'ACIDE ABSISIQUE SUR LA VITELLOGENESE DE SARCOPHAGA BULLATA La vitellogenèse du diptère carnivore, Sarcophaga bullata a été partiellement inhibéc par injection de deux doses de 12 μg d'acide absisique (ABA). Il n'y avait pas de différence significative entre les injections du deuxième et quatrième jour, ou du quatrième et sixième jour La mixture d'isomères a plus inhibé la vitellogenèse que le cis‐trans isomère. ABA n'a pas eu d'effet sur la concentration totale des lipides de l'hémolymphe, mais il a inhibé l'augmentation brutale de la concentration protéique totale de l'hémolymphe, et particulièrement celle de la vitellogénins qui se produit normalement dans les 24 h après consommation de fore le 4ème jour La synthèse de la vitellogémne étant sous le contrôle de l'hormone de mue (MH), l'activité MH a été mesurée par radio‐immunologie, pour découvrir si l'ABA agissait sur la synthèse de la vitellogénine par intermédiaire de son inducteur hormonal. Huit heures après alimentation sur foie, le taux de MH chez les témoins était élevé tandis qu'après traitement avec ABA ce pic n'apparaissait qu'après 18 h. L'effet inhibiteur de l'ABA sur la vitellogénine a pu être neutralisé en fournissant aux mouches du sucre impregné d'ecdystérone (5mg/g), mais non par application locale d'hormone juvénile. Nos résultats suggèrent qu'ABA agit probablement sur un mécanisme commun aux insectes phytophages et non phytophages. Il est peu probable que l'acide absisiq...

Comprehensive and Durable Modulation of Growth, Development, Lifespan and Fecundity in Anopheles stephensi Following Larval Treatment With the Stress Signaling Molecule and Novel Antimalarial Abscisic Acid

“…et al, 2008). The reduction in Vg expression that we observed is consistent with reduced Vg levels in S. bullata injected with ABA (De Man et al, 1981) and reduced Vg levels reported for malnourished A. aegypti (Shiao et al, 2008). Reduced protein content has been shown to result in smaller follicle size and increased resorption of oocytes (Caroci et al, 2004;Clifton and Noriega, 2011).…”

“…Further, ABA affected 20E titers on only a single day of larval development (day 6) at the highest concentration of ABA (100 µM), affirming minimal to no effect of ABA on the interacting effects of JH and 20E. Our data contrast with the reported effects of ABA on 20E in adult S. bullata (De Man et al, 1981), suggesting the likely possibility that the effects of ABA vary to some degree across insect species. In D. melanogaster, reduced food seeking behavior is mediated by the overexpression and release of ILP2 and ILP4 (Wu et al, 2005), suggesting that reduced expression of ilps in our ABA treated larvae might be associated with increased food seeking behavior.…”

“…In the bigheaded grasshopper, Aulocara elliotti, ingested ABA increased the number of eggs per female, however, eggs derived from ABAtreated females exhibited decreased viability (Visscher, 1980). Injection of ABA reduced protein uptake and Vg concentrations following consumption of a liver meal in the flesh fly Sarcophaga bullata (De Man et al, 1981). In addition, ABA injection appeared to act negatively on 20E signaling by delaying the peak of 20E by 16 h (De Man et al, 1981).…”

“…Injection of ABA reduced protein uptake and Vg concentrations following consumption of a liver meal in the flesh fly Sarcophaga bullata (De Man et al, 1981). In addition, ABA injection appeared to act negatively on 20E signaling by delaying the peak of 20E by 16 h (De Man et al, 1981). ABA from nectar and pollen ingested by honeybees (Apis mellifera) can be detected in honey (Lipp, 1990) and ingestion of ABA by honeybee larvae can increase cold tolerance and cellular immunity (Negri et al, 2017;Ramirez et al, 2017).…”

Abscisic acid induces a transient shift in signaling that enhances NF-κB-mediated parasite killing in the midgut of Anopheles stephensi without reducing lifespan or fecundity

“…We reasoned that the changes in ilp expression induced by ABA could have an effect on fecundity as observed in Aedes aegypti [49] and based on observations that injections of ABA reduced vitellogenesis in the flesh fly Sarcophaga bullata [50] . However, ABA had no effect on egg laying rate, clutch size, and egg hatch rate relative to unsupplemented control A. stephensi following a single uninfected blood meal (Fig.…”