Inhibition of molting of the desert locust, Schistocerca gregaria, by the nematode parasite Mermis nigrescens

1974 ◽  
Vol 52 (12) ◽  
pp. 1535-1539 ◽  
Author(s):  
S. M. Craig ◽  
J. M. Webster
Keyword(s):  
Protein Synthesis ◽  
Schistocerca Gregaria ◽  
Fat Body ◽  
Nematode Parasite ◽  
Desert Locust ◽  
Body Protein

The older the host (Schistocerca gregaria) at infection, the greater the burden of parasitic Mermis nigrescens required to inhibit the next-but-one molt. Mermithid parasitism caused no change in ecdysone level in the host, but did cause a decrease in fat body protein synthesis. The effect of this decrease on host molting is discussed.

scholarly journals The mechanism of C-20 hydroxylation of α-ecdysone in the desert locust, Schistocerca gregaria

1977 ◽  
Vol 168 (3) ◽  
pp. 513-520 ◽  
Author(s):  
P Johnson ◽  
H H Rees
Keyword(s):  
Schistocerca Gregaria ◽  
Fat Body ◽  
Difference Spectrum ◽  
Maximum Activity ◽  
Malpighian Tubules ◽  
Desert Locust ◽  
Ph Optimum ◽  
Developmental Variation ◽  
Moulting Hormone ◽  
Cytochrome P 450

1. The C-20 hydroxylation of alpha-ecdysone to produce beta-ecdysone was investigated in the desert locust, Schistocerca gregaria. 2. alpha-Ecdysone C-20 hydroxylase activity was located primarily in the fat-body and Malpighian tubules. The properties of the hydroxylation system from Malpighian tubules investigated further. 3. The enzyme system was mitochondrial, had a pH optimum of 6.5, an apparent Km of 12.5 micron and required O2 and NADPH. 4. The activity of the hydroxylation system showed developmental variation within the fifth instar, the maximum activity corresponding to the maximum tire of endogenous moulting hormone. The significance of these results is assessed in relation to the control of the endogenous titre of beta-ecdysone. 5. The mechanism of the hydroxylation system was investigated by using known inhibitors of hydroxylation reactions such as CO, metyrapone and cyanide. 6. The CO difference spectrum of the reduced mitochondrial preparation indicated the presence of cytochrome P-450 in the preparation. 7. It concluded that the alpha-ecdysone C-20 hydroxylase system is a cytochrome P-450-deendent mono-oxygenase.

Some effects of the nematode Mermis nigrescens upon carbohydrate metabolism in the fat body of its host, the desert locust Schistocerca gregaria

1971 ◽  
Vol 49 (4) ◽  
pp. 431-434 ◽  
Author(s):  
Roger Gordon ◽  
John M. Webster ◽  
David E. Mead
Keyword(s):  
Carbohydrate Metabolism ◽  
Glycogen Phosphorylase ◽  
Schistocerca Gregaria ◽  
Fat Body ◽  
Constant Level ◽  
Desert Locust ◽  
Carbohydrate Levels ◽  
Fat Bodies

Adult desert locusts were experimentally infected with 50 Mermis nigrescens ova and changes in the fat body carbohydrate levels and glycogen phosphorylase activities recorded. At both 2 and 3 weeks after infection, the parasitism caused a significant reduction in the level of glycogen and non-glycogen carbohydrates in the host fat body, together with a progressive depletion of active and inactive glycogen phosphorylases. By feeding extensively upon the blood carbohydrates of the host, the developing nematode deprives the fat body of carbohydrates and thereby effects a reduction in glycogenesis by the host fat body. Increased catabolism (and (or) decreased anabolism) of the fat body phosphorylases, together with a possible suppression of the host "hyperglycaemic factor" by the nematode, prevent further glycogenolysis by the fat bodies of mermithid-infected locusts and allow a low, constant level of fat body glycogen to be maintained in these insects.

Exogenous substances regulate silkworm fat body protein synthesis through MAPK and PI3K/Akt signaling pathways

Chemosphere ◽  
2017 ◽  
Vol 171 ◽  
pp. 202-207 ◽  
Author(s):  
J.H. Tian ◽  
B. Xue ◽  
J.H. Hu ◽  
J.X. Li ◽  
X.Y. Cheng ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Signaling Pathways ◽  
Fat Body ◽  
Akt Signaling ◽  
Body Protein ◽  
Exogenous Substances

A comparison of nutritional regulation in solitarious- and gregarious-phase nymphs of the desert locust Schistocerca gregaria

2002 ◽  
Vol 205 (1) ◽  
pp. 121-129 ◽  
Author(s):  
S. J. Simpson ◽  
D. Raubenheimer ◽  
S. T. Behmer ◽  
A. Whitworth ◽  
G. A. Wright
Keyword(s):  
Schistocerca Gregaria ◽  
Desert Locust ◽  
Nutritional Regulation ◽  
Body Protein ◽  
Genetic Potential ◽  
Trade Offs ◽  
Nutrient Utilisation ◽  
Two Phases ◽  
Unbalanced Diet ◽  
The Cost

SUMMARY Nutritional regulatory responses were compared for the cryptic ‘solitarious’ and the conspicuously coloured, aggregating ‘gregarious’ phases of the desert locust Schistocerca gregaria. The desert locust has the genetic potential to exist in either phase, changing between them within a lifetime and epigenetically across generations. Our aim was to compare final-instar nymphs of the two phases with respect to key nutritional variables, including (i) points of regulated intake (the ‘intake target’) for protein and carbohydrate, (ii) the nature of trade-offs between over-eating nutrients in excess and under-eating those in deficit when fed nutritionally unbalanced foods, (iii) diet-related patterns of nutrient utilisation, and (iv) the performance consequences of eating nutritionally unbalanced diets. When provided with pairs of nutritionally unbalanced but complementary foods, both phases regulated their intake of protein and carbohydrate to a similar point. However, when confined to foods that were of unbalanced protein to carbohydrate ratio, gregarious nymphs ate more than solitarious insects. Both phases regulated protein growth, but gregarious insects did so to a lower adult body protein content and converted ingested protein to growth less efficiently. When fed a food high in carbohydrate and low in protein, gregarious nymphs deposited more body lipid and survived less well than did solitarious insects. Solitarious nymphs developed more quickly than gregarious nymphs except on the two most extremely unbalanced diets, on which development time was similar. The results are discussed with respect to the different nutritional ecologies of the two phases and used to develop the hypothesis that animals have evolved to trade-off the cost of eating excess of a nutritionally unbalanced diet against the probability of encountering foods of complementary composition in the future.

scholarly journals Purification and characterization of an insulin-related peptide in the desert locust, Schistocerca gregaria: immunolocalization, cDNA cloning, transcript profiling and interaction with neuroparsin

2008 ◽  
Vol 40 (3) ◽  
pp. 137-150 ◽  
Author(s):  
Liesbeth Badisco ◽  
Ilse Claeys ◽  
Matthias Van Hiel ◽  
Elke Clynen ◽  
Jurgen Huybrechts ◽  
...  
Keyword(s):  
Schistocerca Gregaria ◽  
Fat Body ◽  
Sequence Similarity ◽  
Desert Locust ◽  
Adult Males ◽  
Igf Binding Proteins ◽  
Insulin Superfamily ◽  
Related Peptide

Members of the insulin superfamily are not restricted to vertebrates, but have also been identified in invertebrate species. In the current report, we present the characterization of Scg-insulin-related peptide (IRP), an insulin-related peptide in the desert locust, Schistocerca gregaria. This peptide was isolated from corpora cardiaca (CC) extracts by means of a high-performance liquid chromatography (HPLC)-based purification strategy. Subsequent cloning and sequencing of the corresponding cDNA revealed that the encoded Scg-IRP precursor displays the structural organization that is typical for members of the insulin superfamily. Moreover, immunocytochemistry on brain tissue sections demonstrated the presence of Scg-IRP in median neurosecretory cells of the pars intercerebralis and their projections towards the storage part of the CC. Quantitative real-time RT-PCR studies revealed the presence of Scg-IRP transcripts in a variety of tissues, including nervous tissue and fat body. Furthermore, these transcripts showed a tissue- and phase-dependent, temporal regulation during the reproductive cycle of adult males and females. Finally, we demonstrated that Scg-IRP interacts in vitro with a recombinant neuroparsin, a locust protein displaying sequence similarity with vertebrate IGF binding proteins.

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