June 30, 2008

7 Foods to Keep You Young

There are many foods that you are eating everyday. Seven foods here can keep you younger and long life are Olive oil, Yogurt, Fish, Chocolate, Nuts, Wine, and Blueberries.

June 15, 2008

Jasmonates as signals in the wound response

Plant responses to wounding and herbivore attack are orchestrated by complex signaling pathways that link the production of chemical and physical signals at the wound site to activation of gene expression and other cellular processes. The systemic nature of many wound-induced responses provides an attractive opportunity to study intercellular signaling pathways that operate over long distances within the plant. Genetic dissection of the wound-response pathway in tomato indicates that (1) systemin and its precursor protein, prosystemin, are upstream components of an intercellular signaling cascade that requires the biosynthesis and action of jasmonic acid (JA); and (2) physiological processes regulated by this pathway confer host resistance to a broad spectrum of plant invaders. Grafting experiments conducted with mutants defective in systemic wound signaling indicate that systemin functions at or near the wound site to trigger the production of JA, which in turn acts non-cell autonomously to promote systemic defense responses. The location of JA biosynthetic enzymes within the companion cell-sieve element complex of vascular bundles, together with the accumulation of JA in vascular tissues, support a role for jasmonates as phloem-mobile signals. The recent discovery of enzymes involved in the metabolism of JA to volatile methyl-JA and bioactive JA-amino acid conjugates has potential implications for the mechanism by which JA promotes wound signaling. Species-specific differences in the mechanism of wound signaling appear to reflect the way in which the wound-induced jasmonate pathway is regulated by other signals including systemin, cell wall-derived oligosaccharides, ethylene, and insect-derived elicitors. Adding to the complexity of the wound-induced jasmonate cascade are wound-signaling pathways that operate independently of JA.
Source: Journal of Plant Growth Regulation (2004) vol. 23 , p. 223-237

June 10, 2008

Oxylipin metabolism in response to stress

Oxylipins comprise a group of biologically active compounds whose structural diversity is generated by the coordinate action of lipases, lipoxygenases, and a group of cytochromes P450 that are specialized for the metabolism of hydroperoxy fatty acids. Research on oxylipins has focused mainly on the biosynthesis of the plant signaling molecule jasmonic acid, and its role in the regulation of developmental and defense-related processes. Recent genetic studies indicate that metabolic precursors of jasmonate are active as signals in their own right, and that the synthesis and perception of jasmonates is critical for wound-induced systemic defense responses. Increasing evidence indicates that the collective biological importance of oxylipins in plants is comparable to that of the eicosanoid family of lipid mediators in animals.

Source: Current opinion in plant biology (2002) vol. 5, p. 230-236