生物谷报道:加州理工学院的一个研究小组发现,由三种小分子组成的一个混合物在低浓度时对线虫起性激素的作用,而由这三种化合物中的两种所组成的较高浓度的混合物却能诱导一种休眠的幼虫状态,被称为“多尔阶段”(dauer stage)。
性生殖和“多尔”形成(一种能够增加幼虫寿命和韧性的种群控制机制)都是重要的生命史特征。关于它们是由在很大程度上相互交叠的小分子家族调控的发现,既表明线虫生命周期的这些方面之间存在密切联系,同时也与一个普遍现象相关,即对很多生物来说,生殖能力和寿命长短的变化是呈负相关的。(生物谷Bioon.com)
生物谷推荐原始出处:
Nature 454, 1115-1118 (28 August 2008) | doi:10.1038/nature07168
A blend of small molecules regulates both mating and development in Caenorhabditis elegans
Jagan Srinivasan1,7, Fatma Kaplan2,3,4,7, Ramadan Ajredini2,3,4, Cherian Zachariah2,3,4, Hans T. Alborn5, Peter E. A. Teal5, Rabia U. Malik6, Arthur S. Edison2,3,4, Paul W. Sternberg1 & Frank C. Schroeder6
Howard Hughes Medical Institute and Biology Division, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
Department of Biochemistry and Molecular Biology,
McKnight Brain Institute,
National High Magnetic Field Laboratory, University of Florida, PO Box 100245, Gainesville, Florida 32610-0245, USA
Center for Medical, Agricultural and Veterinary Entomology, USDA-ARS, 1600–1700 SW 23rd Drive, PO Box 14565, Gainesville, Florida 32604, USA
Boyce Thompson Institute, Cornell University, Ithaca, New York 14853, USA
These authors contributed equally to this work.
In many organisms, population-density sensing and sexual attraction rely on small-molecule-based signalling systems1, 2. In the nematode Caenorhabditis elegans, population density is monitored through specific glycosides of the dideoxysugar ascarylose (the 'ascarosides') that promote entry into an alternative larval stage, the non-feeding and highly persistent dauer stage3, 4. In addition, adult C. elegans males are attracted to hermaphrodites by a previously unidentified small-molecule signal5, 6. Here we show, by means of combinatorial activity-guided fractionation of the C. elegans metabolome, that the mating signal consists of a synergistic blend of three dauer-inducing ascarosides, which we call ascr#2, ascr#3 and ascr#4. This blend of ascarosides acts as a potent male attractant at very low concentrations, whereas at the higher concentrations required for dauer formation the compounds no longer attract males and instead deter hermaphrodites. The ascarosides ascr#2 and ascr#3 carry different, but overlapping, information, as ascr#3 is more potent as a male attractant than ascr#2, whereas ascr#2 is slightly more potent than ascr#3 in promoting dauer formation7. We demonstrate that ascr#2, ascr#3 and ascr#4 are strongly synergistic, and that two types of neuron, the amphid single-ciliated sensory neuron type K (ASK) and the male-specific cephalic companion neuron (CEM), are required for male attraction by ascr#3. On the basis of these results, male attraction and dauer formation in C. elegans appear as alternative behavioural responses to a common set of signalling molecules. The ascaroside signalling system thus connects reproductive and developmental pathways and represents a unique example of structure- and concentration-dependent differential activity of signalling molecules.