title: Primary structure of an adipokinetic neuropeptide from the rhinoceros beetle, Oryctes rhinoceros L (Coleoptera: Dynastidae).
abstract: BACKGROUND
  Neuropeptides play an important role in cellular communication in vertebrates. This is also true for insects in which many physiological, developmental and behavioral processes are affected by neuropeptides produced in neurosecretory cells of the retrocerebral complex. Small neuropeptides of the adipokinetic hormone/red pigment concentrating hormone family (AKH/RPCH) are one of the important groups of peptides that regulate physiological homeostasis.
  
  
  OBJECTIVE
  The present investigation was carried out to elucidate the primary structure of adipokinetic neuropeptides in the rhinoceros beetle, O. rhinoceros.
  
  
  RESULTS
  In the present investigation, an adipokinetic neuropeptide from the coconut pest, Oryctes rhinoceros was isolated from corpora cardiaca by HPLC; the chromatographic fractions were tested for adipokinetic activity in the plant bug, Iphita limbata in vivo. Two UV absorbance peaks were found to be significantly active in elevating haemolymph lipid levels. MALDI-MS analysis of the extract indicated that the molecular mass, 1003.70 Da is similar to the already known AKH from another beetle, Melolontha melolontha. MALDI-MS/MS analysis confirmed that its primary structure is exactly similar to the structure reported for the Melme-AKH (pE-L-N-Y-S-P-D-W-NH2).
  
  
  CONCLUSIONS
  The findings suggest that the distribution of AKH peptides has shown that there exists a taxonomic order or family specificity. This data can be used as additional information to aid in the construction of phylogenetic trees by means of computer programme and protein parsimony algorithms.
authors.affiliation: Division of Insect Biochemistry and Physiology, Department of Zoology, University of Calicut, Kerala - 673 635, INDIA.
authors.forename: A P
authors.initials: AP
authors.lastname: Ajay Kumar
authors.affiliation: Division of Insect Biochemistry and Physiology, Department of Zoology, University of Calicut, Kerala - 673 635, INDIA.
authors.forename: M
authors.initials: M
authors.lastname: Gokuldas
keywords: Adipokinetic hormone; HPLC; MALDI-MS/MS; Neuropeptides; Oryctes rhinoceros