生物谷報道：加州理工學(xué)院的一個研究小組發(fā)現(xiàn)，由三種小分子組成的一個混合物在低濃度時對線蟲起性激素的作用,，而由這三種化合物中的兩種所組成的較高濃度的混合物卻能誘導(dǎo)一種休眠的幼蟲狀態(tài),，被稱為“多爾階段”（dauer stage）。
性生殖和“多爾”形成（一種能夠增加幼蟲壽命和韌性的種群控制機制）都是重要的生命史特征,。關(guān)于它們是由在很大程度上相互交疊的小分子家族調(diào)控的發(fā)現(xiàn),，既表明線蟲生命周期的這些方面之間存在密切聯(lián)系，同時也與一個普遍現(xiàn)象相關(guān),，即對很多生物來說,，生殖能力和壽命長短的變化是呈負相關(guān)的。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
