An RNA G-quadruplex is essential for cap-independent translation initiation in human VEGF IRES

RNA G-quadruplexes located within the 5'-UTR of mRNA are almost always known to be associated with repression of cap-dependent translation. However, in this report we present functional as well as structural evidence that sequence redundancy in a G-rich segment within the 5'-UTR of human VEGF mRNA supports a 'switchable' RNA G-quadruplex structure that is essential for IRES-mediated translation initiation. Additionally, utilization of a specific combination of G-tracts within this segment allows for the conformational switch that implies a tunable regulatory role of the quadruplex structure in translation initiation. A sequence engineered from a functionally handicapped mutant moderately rescued the activity, further indicating the importance of G-quadruplex structure for VEGF IRES-A function. This to our knowledge is the first report of a conformationally flexible RNA G-quadruplex which is essential for IRES-mediated translation initiation.     

A Practical,Flexible and Highly Stereocontrolled Approach to Densely Functionalized Diquinanes

The Diels-Alder adduct 1 has been tailored into the difficultly accessible angularly substituted diquinanes 6a-d in high overall yield.     

Parity violation in a gravitational theory with torsion: A geometrical interpretation

In a space-time with torsion, the action for the gravitational field can be extended with a parity-violating piece. We show how to obtain such a piece from geometry itself, by suitably modifying the affine connection so as to include a pseudo-tensorial part. A consistent method is thus suggested for incorporating parity-violation in the Lagrangians of all matter fields with spin in a space-time background with torsion.     

Studies on indian medicinal plants,part LXXIX : Synthesis proves the structure of aristolindiqu inone

Aristolindiquinone ($\text{1}$) , the first naturally occurring 8-methyl-juglone earlier isolated from $\text{Aristolochia indica}$ has been synthesised from $\text{o}$-allyl-$\text{p}$-cresol in 7% overall yield.     

Optical and magnetic properties of manganese-incorporated zinc sulfide nanorods synthesized by a solvothermal process

Manganese-incorporated ZnS (MnxZn1-xS) nanorods were synthesized by a simple solvothermal process. Synthesized nanorods were single crystalline. Manganese incorporation in the ZnS lattice induces a phase transformation from hexagonal wurtzite to cubic zinc blende structure. The diameter of the nanorods increased with the increase of Mn concentration. Intense orange luminescence at approximately 585 nm was observed for the nanorods. Six-line hyperfine splitting was observed in the EPR spectra for lower Mn concentrations, whereas broad Lorentzian-shaped EPR spectra were obtained for higher Mn concentrations because of the Mn-Mn cluster formation at higher Mn concentrations.     

The first reported syntheses and characterisation of alkali metal trifluoronickelate(II) monohydrates,MNiF3 · H2O (M = NH4, Na or K)

Summary Ni(acac)₂ · (H₂O)₂ (1 mol) and alkali metal fluorides (4 mols), MF (M=NH₄, Na or K), react with an excess of 40% HF on a steam-bath. The product upon treatment with water gives light green crystalline alkali metal trifluoronickelate(II) monohydrate, MNiF₃ · H₂O in a high yield. Chemical analyses, pyrolysis at 120 °C, i.r. spectroscopic, and cryomagnetic (300–80 K) data have been used to characterise, and establish the identity of the compounds. While NH₄NiF₃ · H₂O behaves as a normal octahedral nickel(II) compound, NaNiF₃ · H₂O is ferromagnetic with Curie point 145 K, KNiF₃ · H₂O behaves antiferromagnetically; its Neel point is 230 K.     

Synthesis,physico-chemical and antimicrobial studies on acetylferrocenyl hydrazone derivatives of dichlorobis(cyclopentadienyl)hafnium(IV)

The reactions of Cp₂>HfCl₂> with hydrazones (LH) derived from acetylferrocene and aromatic acid hydrazides (benzoic, 2-chlorobenzoic, 3-nitrobenzoic and 4-toluic) in various stoichiometric ratios have been studied and the complexes of the types [Cp₂>Hf(L)Cl] and [CpHf(L)₃>] were obtained. Tentative structural conclusions are drawn for the reaction products based upon elemental analyses, electrical conductance, magnetic moment and spectral data (u.v.–vis, i.r., ¹>H-n.m.r. and ¹³>C-n.m.r.). Studies were conducted to assess the growth-inhibiting potential of the complexes synthesized, and the ligands, against various fungal and bacterial strains.