Relative oxygenase activities in Juvenile hormone biosynthesis of corpora allata of an african locust (Schistocerca gregaria) and American cockroach (Periplaneta americana)

1975 ◽  
Vol 31 (1) ◽  
pp. 120-122 ◽  
Author(s):  
G. E. Pratt ◽  
S. S. Tobe ◽  
R. J. Weaver
Keyword(s):  
Juvenile Hormone ◽  
Periplaneta Americana ◽  
Schistocerca Gregaria ◽  
American Cockroach ◽  
Corpora Allata ◽  
Juvenile Hormone Biosynthesis ◽  
Hormone Biosynthesis

scholarly journals The influence of substrate concentrations on the rate of insect juvenile hormone biosynthesis by corpora allata of the desert locust in vitro

1974 ◽  
Vol 144 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Stephen S. Tobe ◽  
Grahame E. Pratt
Keyword(s):  
Juvenile Hormone ◽  
Schistocerca Gregaria ◽  
Corpora Allata ◽  
Synthetic Activity ◽  
Methyl Farnesoate ◽  
Physiological Concentration ◽  
Juvenile Hormone Biosynthesis ◽  
Hormone Biosynthesis ◽  
Influence Of Substrate

The rate at which isolated corpora allata of adult female Schistocerca gregaria incorporate [3H]farnesenic acid and [14C]methionine into C16juvenile hormone in vitro was examined at different concentrations of farnesenic acid, methionine, O2 and H+ ions. Maximum juvenile hormone biosynthesis is obtained at a farnesenic acid concentration of 20μm. The range of optimum l-methionine concentrations (0.1–0.4mm) encompasses the physiological concentration of this substrate in the haemolymph. Hormone biosynthesis is dependent on O2, but is not stimulated by hyperbaric oxygen tension. The glands had a maximum synthetic activity at pH8.0, but their activity was more reproducible in the the physiological range pH7.0–7.5. At pH6.5 and less, the synthetic ability was considerably decreased. The relative incorporations of the labelled substrates into methyl farnesoate and C16 juvenile hormone indicate that [3H]farnesenic acid comes into isotopic equilibrium within the gland more rapidly than [14C]methionine. The incorporations into methyl farnesoate become stoicheiometric after 20min incubation and into C16 juvenile hormone after a further 10min. Labelled juvenile hormone is detectable after 10min incubation and the rate of incorporation is constant for up to 4h. It is proposed that the described method may be usefully employed to assess the physiological changes in the enzymic competence of the glands to effect the last two stages in C16 juvenile hormone biosynthesis.

Juvenile hormone biosynthesis by the corpora allata of the male desert locust, Schistocerca gregaria, during sexual maturation

1978 ◽  
Vol 56 (10) ◽  
pp. 2097-2102 ◽  
Author(s):  
L. I. Avruch ◽  
S. S. Tobe
Keyword(s):  
Juvenile Hormone ◽  
Sexual Maturation ◽  
Time Course ◽  
Schistocerca Gregaria ◽  
Dry Weight ◽  
Corpora Allata ◽  
Gas Liquid Chromatography ◽  
Juvenile Hormone Biosynthesis ◽  
Hormone Biosynthesis

The time course of release of C16 juvenile hormone (JH III) from isolated corpora allata (CA) of male Schistocerca gregaria was followed at selected times during sexual maturation. The rates of JH release over an 8-h incubation period were observed to be directly related to the age of the animals: CA from younger animals showed low rates of release (days 5 and 8) whereas CA from older animals showed intermediate to high rates of release (days 12–13). The mean rate of JH release is linear for at least 4 h. The only biosynthesized JH which could be detected in the incubation medium by radio gas–liquid chromatography was C16JH.The dry weight of the accessory reproductive glands (ARG) was also followed during the period of sexual maturation. This increased rapidly between days 10 and 15 and leveled off thereafter. The biosynthesis of C16JH, as determined by a radiochemical assay in vitro, also increased during this period, suggesting a functional relationship between synthesis of ARG secretion and JH.

On the Specificity of Juvenile Hormone Biosynthesis in the Male Cecropia Moth

1981 ◽  
Vol 36 (7-8) ◽  
pp. 579-585 ◽  
Author(s):  
Martin G. Peter ◽  
Paul D. Shirk ◽  
Karl H. Dahm ◽  
Herbert Roller
Keyword(s):  
Juvenile Hormone ◽  
Enzyme System ◽  
Reaction Rates ◽  
Corpora Allata ◽  
Low Molecular Weight ◽  
Methyltransferase Activity ◽  
Accessory Sex Glands ◽  
Juvenile Hormone Biosynthesis ◽  
Hormone Biosynthesis ◽  
Natural Enantiomer

Abstract The accessory sex glands (ASG) of adult male Cecropia contain an enzyme that methylates juvenile hormone acids (JH-acids) in the presence of S-adenosyl-L-methionine (SAM). The methyltransferase is highly specific. The reaction rates decrease in the order JH-I-acid, JH-II-acid and JH-III-acid; in each case the natural enantiomer is esterified predominantly. Methyltrans­ ferase activity with the same substrate specificity was also demonstrated in adult female corpora allata (CA). Male CA have only marginal methyltransferase activity. The CA of male H. cecropia contain substantial amounts of JH-I-acid and JH-II-acid (minimum: 5 pmol/pair). When kept in organ culture, they release JH-acids into the medium. Radiolabeled propionate and mevalonate are incorporated efficiently into the carbon skeletons of the JH-acids. The enzyme system performing these transformations cannot be forced to produce JH-III-acid even in the presence of high mevalonate concentrations, though homomevalonate may enhance biosynthesis of JH-I-acid and JH-II-acid more than tenfold. It becomes evident that the regulation of JH titer balances with regard to the homologous structures during insect development is not merely a question of the availability of low molecular weight precursors, but in addition that of highly specific enzymes acting as regulatory entities in the later steps of the biosynthetic sequence.

Juvenile hormone biosynthesis during sexual maturation and after mating in the adult male migratory grasshopper, Melanoplus sanguinipes

1985 ◽  
Vol 63 (12) ◽  
pp. 2789-2792 ◽  
Author(s):  
G. A. Couche ◽  
C. Gillott ◽  
S. S. Tobe ◽  
R. Feyereisen
Keyword(s):  
Juvenile Hormone ◽  
Adult Male ◽  
Sexual Maturation ◽  
Adult Emergence ◽  
Corpora Allata ◽  
Melanoplus Sanguinipes ◽  
Juvenile Hormone Iii ◽  
Juvenile Hormone Biosynthesis ◽  
Single Mating ◽  
Hormone Biosynthesis

Juvenile hormone III is the exclusive juvenile hormone produced by the corpora allata in adult male Melanoplus sanguinipes. For the first 5 days after adult emergence, the rate of juvenile hormone biosynthesis is low, it then increases rapidly to peak on day 7. Between days 7 and 12 the rate declines to that of newly emerged males and then increases again in 14-day insects. In males allowed a single mating on day 7, the rate of juvenile hormone biosynthesis remains elevated at least to day 12.

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