Department of Biology, Texas A&M University, 77843, College Station, Texas.
J Chem Ecol. 1990 Jan;16(1):121-31. doi: 10.1007/BF01021274.
The flagellate male and female gametes of the aquatic fungusAllomyces macrogynus are each attracted to a sexual pheromone produced by the opposite gamete type. The sperm attractant, sirenin, causes chemotaxis to female gametes. Examination of sperm chemotaxis shows that the pheromone influences the frequency of directional changes and the duration of a chemotactic run. Physiological experiments using tertiary amine local anesthetics or calcium chelators such as EGTA demonstrate that sirenin stimulates the influx of calcium ions (Ca(2+)) into the sperm cytoplasm. Radiological experiments with(45)CaCl2 have demonstrated this calcium flux directly. Structurally, sirenin is an oxygenated sesquiterpene that consists of a cyclopropyl ring attached onto an isohexenyl side chain. The pheromone displays a threshold concentration for attraction at 10 pM in chemotaxis bioassays. Structure-activity relationships with racemic sirenin and sirenin analogs indicate that biological activity requires a terminal hydroxymethyl group on the side chain. In addition, a hydrophobic group must be present at the other end of the sirenin molecule. Besides sirenin, the sperm cells ofA. macrogynus produce a female attractant, parisin. While the molecular nature of this attractant is not completely resolved, some general features of the molecule suggest it may be similar structurally to sirenin.
水生真菌大卵菌的鞭毛雄配子和雌配子都被相反配子类型产生的性信息素吸引。精子引诱剂 sirenin 引起雌配子的趋化性。对精子趋化性的研究表明，信息素影响定向变化的频率和趋化性运动的持续时间。使用叔胺局麻药或 EGTA 等钙螯合剂进行的生理实验表明，sirenin 刺激钙离子 (Ca(2+)) 流入精子细胞质。用(45)CaCl2 进行的放射学实验直接证明了这种钙流。结构上，sirenin 是一种含氧倍半萜，由一个环丙基环连接到异戊烯基侧链上。在趋化性生物测定中，该信息素在 10 pM 时显示出吸引的阈值浓度。与外消旋 sirenin 和 sirenin 类似物的结构-活性关系表明，生物活性需要侧链上的末端羟甲基基团。此外，sirenin 分子的另一端必须存在一个疏水性基团。除了 sirenin，A. macrogynus 的精子细胞还产生一种雌性引诱剂 parisin。虽然这种引诱剂的分子性质尚未完全确定，但该分子的一些一般特征表明它在结构上可能与 sirenin 相似。
