A Protein Synthesis Stimulating Hormone in the Locust

Carlisle, James A.; Loughton, B.G.

doi:10.1007/978-1-4684-4643-2_23

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…The use of HP-SEC fractions may have separated possibly modulating/counteracting molecules from the active fractions. The finding that no biological activity was detected after a second HPLC run is reminiscent of the results obtained for the protein synthesis-stimulating factor (Carlisle and Loughton, 1984) which also displayed a small molecular weight and was unstable after freezing and thawing. Clearly more experiments are required to assess whether the decrease of hemolymph carbohydrates and stimulation of protein synthesis in the fat body are linked to the same molecule.…”

Section: Discussionmentioning

confidence: 50%

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Hypolipemia, hypoglycemia, and inactivation of glycogen phosphorylase in Locusta migratoria

Siegert

1995

Arch Insect Biochem Physiol

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Feeding starved adult migratory locusts, Locusta rnigraforia, caused decreases of hemolymph lipid concentrations and of the percentage of active fat body glycogen phosphorylase which suggested that a molecule(s) from the neurosecretory system or the midgut may have been released to regulate metabolism. Fat body phosphorylase was also inactivated after insects were transferred from 0 to 25°C. In adults with elevated hernolymph lipid levels after the injection of small doses of corpus cardiacum extract (CC), feeding did not induce a decrease in hemolymph lipid concentrations. It appears that the processes initiated by feeding could not override the effects of the continued presence of adipokinetic hormonels) (AKHs) in the hemolymph or their long-term effects.Aqueous, methanolic, or ethanolic extracts of brains or storage lobes (SL) of fed locust CC did not lead to decreases of hemolymph lipid concentrations.Bovine insulin was equally inactive when tested at doses which were previously reported to reduce lipid levels. Fractions of ethanolic brain extracts from 3-day-starved males collected after high-performance size-exclusion chromatography, however, produced hypoglycemic effects in fed males. Two biologically active fractions were found, one with high (2 10 kDa) and one with low molecular weight (approximately 1 kDa). o 1995 Wiley-Liss, Inc.

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Section: Discussionmentioning

confidence: 50%

“…These effects could be mimicked by bovine insulin. Feeding also caused the presence of a factor (apparent molecular weight of approximately 600 Da) in the hemolymph which stimulated protein synthesis (Carlisle et al, 1987) and was unstable to freezing and thawing (Carlisle and Loughton, 1984).…”

Section: Introductionmentioning

confidence: 99%

Hypolipemia, hypoglycemia, and inactivation of glycogen phosphorylase in Locusta migratoria

Siegert

1995

Arch Insect Biochem Physiol

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Direct manipulation of insect reproduction by agents of parasite origin

Webb

Hurd

1999

Proc. R. Soc. Lond. B

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Reproductive output of female Tenebrio molitor beetles is reduced upon infection with metacestodes of the rat tapeworm, Hymenolepis diminuta. We are using this as a model to investigate the adaptive signi¢cance of parasite-induced curtailment of insect reproduction. Production of the yolk protein vitellogenin (Vg) in the insect fat body is signi¢cantly reduced both in vitro and in vivo by metacestodes. Synthesis can be measured by using [14 C]L-leucine incorporation, followed by immunoprecipitation. In this paper we demonstrate that a signi¢cant decrease in [14 C]Vg can be produced by an acetic acid extract of the parasite. Conclusive evidence is presented that the active component(s) originate from the metacestodes: an extract of parasites grown entirely axenically has similar deleterious e¡ects. The developmental stage of the metacestode is important: immature (stage I^II) parasites had greater capacity to suppress Vg synthesis than mature ones (stage V^VI). Examination of the chemical nature of the e¡ector molecule(s) revealed that acetic-acid-extractable, boiling-resistant, pronase-sensitive agents in the molecular mass range 10^50 kDa reduced Vg synthesis by 47.4%. These data suggest that metacestodes produce a modulator molecule that directly a¡ects insect vitellogenesis and, therefore, that reduction of host ¢tness may confer a selective advantage upon the parasite.

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A Protein Synthesis Stimulating Hormone in the Locust

Cited by 2 publications

References 2 publications

Hypolipemia, hypoglycemia, and inactivation of glycogen phosphorylase in Locusta migratoria

Hypolipemia, hypoglycemia, and inactivation of glycogen phosphorylase in Locusta migratoria

Direct manipulation of insect reproduction by agents of parasite origin

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