Abiotic stress induces differential expression of genes responsible for the synthesis of raffinose family of oligosaccharides (RFOs) in plants. RFOs are described as the most widespread D-galactose containing oligosaccharides in higher plants. Biosynthesis of RFOs begin with the activity of galactinol synthase (GolS; EC 2.4.1.123), a GT8 family glycosyltransferase that galactosylates myo-inositol to produce galactinol. Raffinose and the subsequent higher molecular weight RFOs (Stachyose, Verbascose, and Ajugose) are synthesized from sucrose by the subsequent addition of activated galactose moieties donated by Galactinol. Interestingly, GolS, the key enzyme of this pathway is functional only in the flowering plants. It is thus assumed that RFO synthesis is a specialized metabolic event in higher plants; although it is not known whether lower plant groups synthesize any galactinol or RFOs. In higher plants, several functional importance of RFOs have been reported, e.g., RFOs protect the embryo from maturation associated desiccation, are predominant transport carbohydrates in some plant families, act as signaling molecule following pathogen attack and wounding and accumulate in vegetative tissues in response to a range of abiotic stresses. However, the loss-of-function mutants reported so far fail to show any perturbation in those biological functions. The role of RFOs in biotic and abiotic stress is therefore still in debate and their specificity and related components remains to be demonstrated. The present review discusses the biology and stress-linked regulation of this less studied extension of inositol metabolic pathway.

Salinity poses a serious threat to yield performance of cultivated rice in South Asian countries. To understand the mechanism of salt-tolerance of the wild halophytic rice, Porteresia coarctata in contrast to the salt-sensitive domesticated rice Oryza sativa, we have compared P. coarctata with the domesticated O. sativa rice varieties under salinity stress with respect to several physiological parameters and changes in leaf protein expression. P. coarctata showed a better growth performance and biomass under salinity stress. Relative water content was conserved in Porteresia during stress and sodium ion accumulation in leaves was comparatively lesser. Scanning electron microscopy revealed presence of two types of salt hairs on two leaf surfaces, each showing a different behaviour under stress. High salt stress for prolonged period also revealed accumulation of extruded NaCl crystals on leaf surface. Changes induced in leaf proteins were studied by two-dimensional gel electrophoresis and subsequent quantitative image analysis. Out of more than 700 protein spots reproducibly detected and analyzed, 60% spots showed significant changes under salinity. Many proteins showed steady patterns of up- or downregulation in response to salinity stress. Twenty protein spots were analyzed by MALDI-TOF, leading to identification of 16 proteins involved in osmolyte synthesis, photosystem functioning, RubisCO activation, cell wall synthesis and chaperone functions. We hypothesize that some of these proteins confer a physiological advantage on Porteresia under salinity, and suggest a pattern of salt tolerance strategies operative in salt-marsh grasses. In addition, such proteins may turn out to be potential targets for recombinant cloning and introgression in salt-sensitive plants.

I. General Methods and materials: Unless otherwise noted, all commercial reagents and solvents were obtained from the commercial provider and used without further purification. Anhydrous toluene was distilled from sodium benzophenone ketyl. 1 H-NMR and 13 C-NMR spectra were recorded on Joel 270 and Varian 600 MHz spectrometers. Chemical shifts were reported relative to internal tetramethysilane (δ 0.00 ppm) or CDCl 3 (δ 7.26 ppm) for 1 H and CDCl 3 (δ 77.0 ppm) for 13 C. 31 P-NMR was recorded on Varian 600 MHz spectrometer operating at 242.88 MHz for 31 P. Chemical shifts were reported in ppm down field from internal Me 4 Si and external 85% H 3 PO 4 , respectively. Flash column chromatography was performed on 230-430 mesh silica gel. Melting points were measured on a Mel-Temp 1001D apparatus and uncorrected. HRMS were recorded on LTQ-FTUHRA spectrometer. PPh 3 AuCl 1 , PPh 3 AuNTf 2 2 , IPrAuNTf 2 2 were prepared according to the reported procedure Procedure for synthesis of Triazole-Gold complex 2a, 2b NaOH 1.0 eq., PPh 3 AuCl 1.0 eq. MeOH, rt,

Au revoir: Recent years have seen explosive growth in the use of homogeneous gold catalysts, owing to their excellent chemoselectivity, high efficiency, and applicability under mild conditions. In this Minireview, recent progress regarding asymmetric gold catalysis is summarized with discussion focused on homogeneous Au catalysts promoting CC multiple bond activation toward the synthesis of enantiomerically enriched products.

The cyclooxygenase-2 (COX-2) gene encodes the inducible prostaglandin synthase enzyme implicated in inflammation, cell growth, and tumorigenesis. Regulation of the COX-2 gene expression at the post-transcriptional level is poorly understood. For example, protein factors that regulate the post-transcriptional mRNA metabolism of COX-2 have not been fully characterized. In this study, we demonstrate that the RNA-binding protein HuR binds to COX-2 mRNA and regulates its expression. We show that there are three binding sites for HuR in the 3-untranslated region of human COX-2. These sites are located at the following positions in the COX-2 3-untranslated region: 39 -84 nucleotides (nt), 1155-1187 nt, and 1244 -1256 nt (hereinafter referred to as Sites I, II and III, respectively). Although all three sites are present in the 4.6-kb COX-2 mRNA, only site I is present in the shorter 2.8-kb isoform. HuR in MDA-MB-231 cell extracts associated with COX-2 mRNA at the identified sites. Further, HuR location in the cytoplasm was induced by serum withdrawal, a stimulus known to induce COX-2 mRNA. Down-regulation of HuR by two independent methods, namely RNA interference as well as antisense RNA expression, significantly attenuated serum withdrawal-induced increase in COX-2 mRNA (both the 4.6-and 2.8-kb isoforms) and protein levels. These data suggest that HuR binding to COX-2 is critical for its post-transcriptional mRNA stabilization.