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Haemolymph levels of Schistocerca gregaria ion transport peptide and ion transport‐like peptide
Author(s) -
Audsley N.,
Meredith J.,
Phillips J. E.
Publication year - 2006
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.2006.00500.x
Subject(s) - schistocerca , hemolymph , locust , biology , peptide , desert locust , high performance liquid chromatography , rhodnius prolixus , medicine , endocrinology , antibody , biochemistry , insect , chromatography , immunology , chemistry , botany
. Titres of ion transport peptide (ITP) and ion transport‐like peptide (ITP‐L) in the haemolymph of the desert locust Schistocerca gregaria Forskål are investigated using a combination of enzyme‐linked immunosorbent assay and reversed‐phase high‐performance liquid chromatography (HPLC). The estimated circulating levels of these two peptides are used to investigate their putative physiological roles. Haemolymph levels of ITP‐L are significantly higher in fed and exercise‐stressed locusts than in starved insects, suggesting a role for ITP‐L in postfeeding osmoregulation and metabolism associated with stress. The higher titres of ITP‐L in the final nymphal stadium could be related to increased levels of ecdysteroids over this same period. In addition detection of ITP‐L in the brain and corpus cardiacum of the locust demonstrates for the first time that the ITP‐L is expressed in these tissues. Immunoreactivity to antibodies raised against ITP is significantly higher in fed locusts compared with starved insects. However, >95% of this immunoreactivity elutes later than synthetic ITP when separated by HPLC. The results suggest that this more hydrophobic immunoreactivity is neither native ITP nor a metabolic breakdown product of ITP. Haemolymph levels of immunoreactivity to ITP during the last nymphal stadium are similar to ITP‐L but, unlike ITP‐L, there is no measured increase in immunoreactivity to ITP due to exercise stress.