A neuropeptide family from the sinus gland of the Mexican crayfish, Procambarus bouvieri (Ortmann)

• Published in: Aquaculture Vol. 135; no. 1; pp. 149 - 160
• Main Authors: Huberman, Alberto, Aguilar, Manuel B., Quackenbush, L.Scott
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.1995; Elsevier Sequoia S.A
• Subjects: Crustacean; Crustaceans; ENDOCRINE GLANDS; Endocrine system; GLANDE ENDOCRINE; GLANDULAS ENDOCRINAS; Gonads; High pressure; Hormone; Liquid chromatography; Neurology; PEPTIDE; PEPTIDES; PEPTIDOS; PROCAMBARUS; Procambarus bouvieri; Procambarus bouvieri, Neuropeptide; SENOS; Shellfish; SINUS; Sinus gland; SINUSES; Hormone; Sinus gland; Gonads; Crustacean; Procambarus bouvieri, Neuropeptide
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/0044-8486(95)01010-6

The main neuroendocrine axis of crustaceans is constituted by the brain, medulla terminalis X-organ (MTXO) -sinus gland (SG) system. A variety of hormonal peptides are synthesized in the MTXO where the peptidergic neuronal somata are situated. The peptides are then transported via axonic flow to the SG, which is a conglomerate of bulbous axonic terminals in close contact with the hemolymph, where these hormones are liberated to the circulation by a process of exocytosis. Four peptides have been isolated from crude aqueous extracts of microdissected SG of the Mexican crayfish, Procambarus bouvieri, by means of a single-step reverse-phase high pressure liquid chromatography (RP-HPLC) on a μBondapak-Phenyl column; these have been characterized physiologically by specific bioassays, and structurally by means of tryptic peptide mapping and sequencing. These procedures have identified (in the order of elution) a gonad-inhibiting hormone (GIH), a molt-inhibiting hormone (MIH), a major isomorph of the crustacean hyperglycaemic hormone (CHH-I) and its minor isomorph (CHH-II), in approximate concentrations of 5, 18, 60, and 20 ng per SG, respectively. Their common characteristics are: (1) acidic pl, (2) hydrophobicity, (3) molecular masses between 8300 and 8400 Da, (4) approximately 72 amino acid residues, (5) blocked N- and C-termini, (6) six cysteines forming three disulfide bridges, (7) lack of histidine, methionine, and tryptophan residues, (8) long tracts of sequence identity. These features clearly establish these four peptides as members of one neuropeptide family. Recently, a factor with gonad-stimulating activity has been isolated from this same crude extract by means of RP-HPLC. This factor stimulated by 300% the specific incorporation of radioactive leucine into yolk proteins in an in vitro bioassay consisting in the incubation of ovary fragments from the adult female shrimp, Penaeus vannamei, and immunoprecipitation of the proteins with a specific antibody to shrimp yolk protein. Thus, the SG extract from the crayfish, P. bouvieri, contains both a gonad-inhibiting hormone and a gonad-stimulating hormone (GSH), capable of acting on ovarian yolk protein synthesis in the shrimp, P. vannamei. The output of shrimp larvae spells the success of a shrimp hatchery. The induction of maturation of shrimp in captivity is done at present via eyestalk ablation of female broodstock, but this method causes increased mortality, disruption of the shrimp's endocrine system, and decreased larval viability with repeated spawnings. GSH could be used in aquaculture to increase the effect of eyestalk ablation or to substitute for this procedure completely.