Kuhlmann H W, Brünen-Nieweler C, Heckmann K
Institut für Allgemeine Zoologie und Genetik, Universität Münster, Germany.
J Exp Zool. 1997 Jan 1;277(1):38-48.
Cells of the ten mating types of the ciliate Euplotes octocarinatus communicate by pheromones before they enter conjugation. The pheromones induce homotypic pairing when applied to mating types that do not secrete the same pheromone(s). Heterotypic pairs (i.e., those between cells of different mating types) are formed only when both mating types in a mixture secrete a pheromone that the other does not. The genetics of mating types is based on four codominant mating type alleles, each allele determining production of a different pheromone. Here we report that the pheromones not only induce pair formation but also attract cells. This was shown by placing cells of various mating types in neighboring agar wells so that the pheromones could diffuse from one well to the next. We found that the cells accumulated on the side of the well where a pheromone entered by diffusion. This response was observed only if the pheromone had the capacity to induce the cells to conjugate. That the pheromones and not some other substances attract the cells was shown by placing pheromone 3, expressed in Escherichia coli, in wells next to tester strains. Mating types known to respond to pheromone 3 by pair formation also showed accumulation on the side of the well at which the pheromone entered by diffusion. Since the pattern of cell attraction corresponds with the pattern of conjugation induction, we suggest that not only conjugation induction but also cell attraction is governed by pheromone-specific receptors. In addition, we describe a succession of changes in the behavior of cells affected by the pheromones.
八肋游仆虫（Euplotes octocarinatus）的十种交配型细胞在进入接合之前通过信息素进行通讯。当将信息素应用于不分泌相同信息素的交配型时，这些信息素会诱导同型配对。异型配对（即不同交配型细胞之间的配对）仅在混合物中的两种交配型都分泌另一种交配型不分泌的信息素时才会形成。交配型的遗传学基于四个共显性的交配型等位基因，每个等位基因决定一种不同信息素的产生。在此，我们报告信息素不仅诱导配对形成，还吸引细胞。这是通过将各种交配型的细胞放置在相邻的琼脂孔中，使信息素能够从一个孔扩散到另一个孔来证明的。我们发现细胞聚集在信息素通过扩散进入的孔的一侧。仅当信息素具有诱导细胞接合的能力时才会观察到这种反应。通过将在大肠杆菌中表达的信息素3放置在测试菌株旁边的孔中，表明是信息素而非其他物质吸引细胞。已知通过配对形成对信息素3作出反应的交配型在信息素通过扩散进入的孔的一侧也显示出聚集。由于细胞吸引模式与接合诱导模式相对应，我们认为不仅接合诱导而且细胞吸引都由信息素特异性受体控制。此外，我们描述了受信息素影响的细胞行为的一系列变化。
