Painter S D, Clough B, Garden R W, Sweedler J V, Nagle G T
Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77555-1043, USA.
Biol Bull. 1998 Apr;194(2):120-31. doi: 10.2307/1543042.
Although animals in the genus Aplysia are solitary during most of the year, they form breeding aggregations during the reproductive season. The aggregations contain both mating and egg-laying animals and are associated with masses of egg cordons. The egg cordons are a source of pheromones that establish and maintain the aggregation, but none of the pheromonal factors have been chemically characterized. In these studies, specimens of Aplysia were induced to lay eggs, the egg cordons collected and eluted, and the eluates fractionated by C18 reversed-phase HPLC. Four peak fractions were bioassayed in a T-maze. All four increased the number of animals attracted to a nonlaying conspecific and were thus subjected to compositional and microsequence analysis. Each contained the same NH2-terminal peptide sequence. The full-length peptide ("attractin") was isolated from the albumen gland, a large exocrine organ that packages the eggs into a cordon. The complete 58-residue sequence was obtained, and it matched that predicted by an albumen gland cDNA. Mass spectrometry showed that attractin is 21 wt.% carbohydrate as the result of N-linked glycosylation. T-maze bioassays confirmed that the full-length peptide is attractive. Attractin is the first water-borne peptide pheromone characterized in molluscs, and the first in invertebrates.
虽然海兔属动物一年中的大部分时间都是独居的，但它们在繁殖季节会形成繁殖群体。这些群体中既有交配的动物，也有产卵的动物，并且与大量的卵索有关。卵索是建立和维持群体的信息素来源，但尚未对任何一种信息素因子进行化学表征。在这些研究中，诱导海兔标本产卵，收集并洗脱卵索，然后通过C18反相高效液相色谱对洗脱液进行分级分离。在T型迷宫中对四个峰级分进行了生物测定。所有四个级分都增加了被未产卵同种个体吸引的动物数量，因此对其进行了成分和微序列分析。每个级分都含有相同的氨基末端肽序列。从蛋白腺（一种将卵包装成卵索的大型外分泌器官）中分离出了全长肽（“吸引素”）。获得了完整的58个残基序列，它与蛋白腺cDNA预测的序列相符。质谱分析表明，由于N-连接糖基化，吸引素含有21%（重量）的碳水化合物。T型迷宫生物测定证实全长肽具有吸引力。吸引素是在软体动物中表征的第一种水溶性肽信息素，也是在无脊椎动物中发现的第一种此类信息素。
