. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SEXUAL PHEROMONES IN ALGAE 169 conservative character of pheromone systems. Thus, complete species-specificity cannot be expected. This is confirmed by the finding of an order-specificity for lamoxirene in Laminariales, and the presence of multifidene in at least two species from divergent phylogenetic lines, Cutleria multifida and Chorda tomentosa. In many cases, female gametes produce considerable amounts of by-products in addition to their specific pheromones. These may act as male-attractants in other species. Moreover,
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SEXUAL PHEROMONES IN ALGAE 169 conservative character of pheromone systems. Thus, complete species-specificity cannot be expected. This is confirmed by the finding of an order-specificity for lamoxirene in Laminariales, and the presence of multifidene in at least two species from divergent phylogenetic lines, Cutleria multifida and Chorda tomentosa. In many cases, female gametes produce considerable amounts of by-products in addition to their specific pheromones. These may act as male-attractants in other species. Moreover, the signal compounds are similar in respect to their physico-chemical properties in the reception process (), particularly in their overall 7r-electron distribution. For example, ec- tocarpene and multifidene show nearly identical topology in an appropriate confor- mation, including double bond arrangement (Fig. 14). The basic molecular mechanism of pheromone-receptor interaction can be assumed to be identical in all brown algae (Roland et al, 1983b; Boland el al, 1984a; Muller el ai, 1985a). In high-sensitivity recognition processes with the potential for one-molecule effects in extreme cases, as seen in certain brown algal pheromone systems (Boland et ai, 1984a), interspecific interferences can be expected. Under laboratory conditions, in- terspecific cross reactions are easily demonstrated. Because of the conformational re- semblance of ectocarpene and multifidene (Fig. 14), Cutleria male gametes react toward ectocarpene in the same manner as to their own pheromone, multifidene (Muller, 1976; Boland et al., 1983b), although at approximately 400-fold higher concentration. This difference can be attributed to the loss of one coordination point caused by the shifted position of one double bond (Boland et al., 1981, 1983b). Conversely, male gametes of Ectocarpus are attracted by Cutleria female gametes and to eggs of Lam- inaria and Alaria, which secrete ectocarpene as a c
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
