RESUMEN
Neuropeptides are small molecules that mediate intercellular signaling and regulate physiological processes. Starfish possess various myoactive neuropeptides, including starfish myorelaxant peptide (SMP) and a calcitonin-type peptide with apical muscle relaxing properties. In this study, we report the purification of a neuropeptide from starfish (Patiria pectinifera) pyloric caeca extract using high-performance liquid chromatography (HPLC) and an in vitro bioassay to screen for fractions and peptides with relaxing effects on P. pectinifera apical muscle preparations. A series of HPLC steps using reversed-phase and cation-exchange columns yielded a purified peptide with muscle-relaxing effects. The purified peptide's structure was determined by LC-MS and Edman degradation, revealing a pentapeptide with an amidated C-terminus (NGFFYamide) and a molecular mass of 646.2930â¯Da. This is the first report of NGFFYamide purification from P. pectinifera through biochemical methods. The nucleotide sequence encoding the NGFFYamide precursor was determined, showing the presence of a conserved neurophysin domain in the C-terminal region. RT-qPCR results confirmed high expression in radial nerves cord, consistent with previous findings on NG peptides in echinoderms. In vitro pharmacological studies on muscle preparations from P. pectinifera and Asterias amurensis revealed differential relaxing activity of NGFFYamide on apical muscles, while its effects on tube foot preparations were similar in both species. NGFFYamide also induced potent contraction in P. pectinifera cardiac stomach. Comparison of three NG peptides (NGFFYamide, NGFFFamide, and NGIWYamide) on P. pectinifera cardiac stomach revealed varying potency, suggesting class-specific receptor interactions. Tachyphylaxis was observed in P. pectinifera apical muscle but not in A. amurensis, warranting further investigation. Based on these results, it is plausible that NGFFYamide could be involved in regulating locomotion and feeding behavior in P. pectinifera, consistent with findings in Asterias rubens.
Asunto(s)
Neuropéptidos , Estrellas de Mar , Animales , Neuropéptidos/farmacología , Neuropéptidos/aislamiento & purificación , Neuropéptidos/química , Neuropéptidos/genética , Estrellas de Mar/química , Secuencia de Aminoácidos , Cromatografía Líquida de Alta Presión , Relajación Muscular/efectos de los fármacosRESUMEN
Marine organisms, such as sea urchins like Heliocidaris crassispina, produce bioactive substances with antimicrobial activity to protect themselves from the high density of microorganisms in their habitats. One such substance, Echinochrome A (Ech A), has been isolated from various sea urchins' shells and spines using strong acidic solutions and organic solvents. Ech A, however, has not been reported from the coelomic fluid of H. crassispina. In this study, we report the antimicrobial activity of H. crassispina coelomic fluid extract against various microbes, evaluating its potential for purifying potent antimicrobial materials. Upon confirming the extract as a promising source of antimicrobial materials, we isolated antimicrobial compounds from the extract. A series of HPLC steps were taken to purify antimicrobial materials from the H. crassispina coelomic fluid extract, resulting in the isolation of two single absorbance peaks showing antimicrobial activity against Staphylococcus aureus. One peak consisted of a single antimicrobial compound with a molecular weight (MW) corresponding to Ech A, while the other peak comprised five MWs inferred to be those of Ech A and its oxidative products. The elution of Ech A in two separate peaks may be attributable to the presence of Ech A's isomer, as reported in several previous studies. The use of the environmentally friendly extraction method in procurement of Ech A from the coelomic fluid would contribute to the implementation of risk-reducing extraction method for researchers studying Ech A from sea urchins.