Increased juvenile hormone synthesis and decreased fertility in aging Schistocerca gregaria

1981 ◽  
Vol 59 (9) ◽  
pp. 1744-1748 ◽  
Author(s):  
H. S. Injeyan ◽  
J. F. Dale ◽  
S. S. Tobe
Keyword(s):  
Juvenile Hormone ◽  
Schistocerca Gregaria ◽  
Corpora Allata ◽  
Synthetic Activity ◽  
Hormone Synthesis ◽  
Young Females ◽  
Old Females

The fertility of aging Schistocerca gregaria females of both solitary and gregarious phases is markedly reduced in comparison with that of young females. Examination of eggs (from both young and aging females) maintained in vitro revealed that the decreased fertility of aging females of both phases could be attributed to a decrease in viability of eggs. This, in turn, was found to be in large part due to an increase in the proportion of embryos showing inhibited development. The proportion of inhibited embryos, in pods from young and old females, respectively, increased from 5 to 42% for gregarious animals and from 3 to 38% for solitary animals. Inhibition was found to occur at all stages from blastokinesis to ecdysis of the provisional cuticle. These morphogenetic aberrations were very similar to those obtained after treatment of S. gregaria eggs with exogenous juvenile hormone (JH). Investigation of the JH synthetic activity of corpora allata from aging females of each phase revealed a marked increase in the rates of JH synthesis in comparison with those of young females of the same phase. Furthermore, injection of JH into young females increased the proportion of embryos showing inhibited development from 7% (in control females) to 30% (in JH-treated females). These results suggest a possible correlation between reduced viability of eggs and high rates of JH synthesis in aging S. gregaria of both phases.

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.

Corpus allatum activity in vitro during ovarian maturation in the desert locust, Schistocerca gregaria

1975 ◽  
Vol 62 (3) ◽  
pp. 611-627
Author(s):  
S. S. Tobe ◽  
G. E. Pratt
Keyword(s):  
Schistocerca Gregaria ◽  
Physiological Activity ◽  
Corpus Allatum ◽  
In Vitro Assays ◽  
Synthetic Activity ◽  
Clear Correlation ◽  
Methyl Farnesoate ◽  
Endocrine Activity ◽  
Hormone Synthesis

1. Radiochemical in vitro assays show that there are large and rapid changes in the spontaneous rate of juvenile hormone synthesis and release during the course of sexual maturation in the locust. 2. Parallel observations on glands incubated with farnesenic acid show that the rate-limiting step is always prior to the stage of esterification of farnesenic acid to the final intermediate, methyl farnesoate. 3. Corresponding changes in oocyte morphometrics do not reveal any clear correlation between endocrine activity of the corpus allatum and either the induction or maintenance of rapid vitellogenesis. 4. Peaks of synthetic activity in the corpus allatum correspond well with the onset of previtellogenic growth in the oocytes. 5. The data do not provide any evidence that ‘corpus allatum insufficiency’ is responsible for resorption of growing oocytes. 6. It is concluded that short-term in vitro radio-assays provide a valid method for estimating quantitatively the physiological activity of the corpus allatum.

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.

Stimulation of Juvenile Hormone Biosynthesis in vitro by Locust Allatotropin

1983 ◽  
Vol 38 (9-10) ◽  
pp. 856-858 ◽  
Author(s):  
Hans-Joerg Ferenz ◽  
Ingrid Diehl
Keyword(s):  
Juvenile Hormone ◽  
Locusta Migratoria ◽  
Corpus Allatum ◽  
Corpora Allata ◽  
Biosynthetic Activity ◽  
Hormone Synthesis ◽  
Heat Stable ◽  
Juvenile Hormone Biosynthesis ◽  
Hormone Biosynthesis

Abstract In Locusta migratoria the gonotrophic cycles are regulated by juvenile hormone. The cyclical changes of juvenile hormone synthesis in locust corpora allata seem to be regulated by a neuro-hormonal factor. Such an allatotropin could be extracted from corpora cardiaca and brains of Locusta migratoria. It is a small pronase-sensitive and heat-stable peptide. Extract of one corpus cardiacum stimulates corpus allatum biosynthetic activity in vitro 5 to 20-fold.

Juvenile hormone synthesis in vitro by larval and pupal corpora allata of Manduca sexta

1982 ◽  
Vol 28 (3) ◽  
pp. 587-604 ◽  
Author(s):  
N.A. Granger ◽  
S.M. Niemiec ◽  
L.I. Gilbert ◽  
W.E. Bollenbacher
Keyword(s):  
Juvenile Hormone ◽  
Manduca Sexta ◽  
Corpora Allata ◽  
Hormone Synthesis
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