1496 



Price, D. A., and M. J. Greenberg. 1975. 



Isolation of a cardioexcitatory oligopeptide from molluscan ganglia. Fed. 

 Proc. 34: 776 (abstract 3154). 



Extracts of molluscan ganglia, including those of Mereenaria meraenaria, 

 contain a substance that increases amplitude of molluscan heart beat or 

 induces rhythmicity . The authors conclude from various experiments that 

 the active substance is an oligopeptide (ca 500 MW) containing at least an 

 arginyl and a phenylalanyl residue. - J.L.M. 



1497 



Price, David A., and Michael J. Greenberg. 1977. 



Structure of a molluscan cardioexcitatory neuropeptide. Science 197(4304): 

 670-671. 



Neurohumors characteristic of mollusks are acetylcholine, 5-hydroxytryptamine , 

 and dopamine. Other substances in aqueous extracts of molluscan ganglia have 

 cardioexcitatory activity. These can be separated chroma tographically, but so 

 far are unidentified. One, up to now called peak C, is of particular interest 

 because it not only can augment the contractile force of molluscan cardiac 

 muscle and induce prolonged contractions of other muscles, but also can 

 restore regular beating of arrhythmic hearts or induce beating in quiescent 

 hearts. Peak C has been found in all major classes of mollusk, concentrated 

 particularly in nervous tissue. Using heart preparations of Mercenavia 

 meraenaria and radula protractor of Busycon as parallel bioassay systems, 

 the authors isolated peak C from ganglion extracts of Macrocatlista nimhosa 

 and purified the extract. Peak C was identified as a tetrapeptide amide 

 having the sequence: Phe-Met-Arg-Phe-NH2 (Phe=phenylalanine; Met=methionine; 

 Arg=arginine) . This appeared to be the correct sequence of 4 possible 

 structures. Another abbreviation, approved by the IUPAC-IUB Commission on 

 Biochemical Nomenclature, is FMRFamide (F, M, and R are one-letter abbreviations 

 for the amino acids Phe , Met, and Arg, and the designation FMRFamide conveys the 

 amino acid sequence of the peptide and the fact that the carboxyl terminal is 

 substituted with an amide group) . Assuming that FMRFamide is a neurosecretory 

 product, its physiological role in mollusks might be as a long-term regulator 

 of muscular rhythmicity and tone. - J.L.M. 



1498 



Price, Kent S. 1978. 



Advances in closed (recirculated) system mariculture. Rev. Biol. Trop. 26 

 (Suppl. 1) : 23-43. 



The long-range collective objective of Delaware's maricultural research is 

 to produce successfully, on algal or prepared foods, or both, desirable, 

 fast growing, palatable, nutritious oysters and clams, free of toxins and 

 pathogens, in a controlled environment seawater system, at reasonable cost, 

 unhampered by legal constraints, using natural sources of energy, and 

 recycling organic wastes. Research began in September 1968. During the 

 7th year (1974-75) clams and oysters were grown to seed size in recirculating 

 seawater systems, and clams ("ereenaria mercenaria) and oysters (Cvassostvea 

 virginica) were raised to edible market size, with growth about three times 

 that of the fastest reported growth in Delaware Bay. Details of other 

 investigations are given. Economic aspects and research needs still to be 

 determined are listed and discussed. Outstanding progress during the past 

 year (1975-76) and the strong interest expressed by industry in the closed 

 system process, cause them to expect to enter into a cooperative industry- 

 University pilot effort to demonstrate the commercial feasibility of closed 

 system bivalve mollusk culture before the end of the 1978-79 grant year. 

 - J.L.M. 



418 



