Beetle diuretic peptides: the response of mealworm (Tenebrio molitor) Malpighian tubules to synthetic peptides, and cross-reactivity studies with a dung beetle (Onthophagus gazella).
This paper reports the effects of different diuretic factors on the Malpighian tubules of beetles. Calcitonin (CT)-like peptides from silkmoth and mosquito increase fluid secretion in a dose-dependent manner in the tubules of Tenebrio molitor, but the cockroach CT-like peptide, Dippu-DH(31), has no effect. Thapsigargin induces a small but significant increase in tubule secretion rates. The interactions between different factors in mealworm tubules were explored by testing CT-like peptides, thapsigargin and the mealworm CRF-related diuretic factor Tenmo-DH(37) in various combinations, but no synergistic effects were observed. C-terminal fragments of the CRF-related diuretic peptides Locmi-DH(46) and Dippu-DH(46) fail to increase fluid secretion in mealworm tubules, unlike their corresponding whole peptides. Cross-reactivity of factors between beetle species was investigated using the scarabaeid Onthophagus gazella. Tenmo-DH(37) increases fluid secretion in isolated tubules of O. gazella in a dose-dependent manner, revealing a high degree of cross-reactivity in this distantly related beetle species. However, homogenates of O. gazella brains inhibited fluid secretion in mealworm tubules.
Holtzhausen
W D
WD
Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa.
Nicolson
S W
SW
D000818:Animals; D001923:Brain Chemistry; D001517:Coleoptera / Q000502:physiology*; D004357:Drug Synergism; D008317:Malpighian Tubules / Q000187:drug effects; D009479:Neuropeptides / Q000494:pharmacology*; D013712:Tenebrio / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology
D009479:Neuropeptides; D019284:Thapsigargin