QSAR study on (13)C NMR chemical shifts on carbinol carbon atoms

QSAR calculations of (13)C NMR chemical shifts (ppm, TMS=0) on carbinol carbon atoms have been attempted using a large set of distance based topological indices: Wiener (W)-, Szeged (Sz)-, PI (Padmakar-Ivan) and Connectivity ((m)chi, (m)chi(v)) indices. The regression analysis has shown that excellent results are obtained in multiparametric regression. The predictive power of the proposed models are discussed using cross-validated parameters.     

QSAR study on phenolic activity: need of positive hydrophobic term (log P) in QSAR

The phenolic activity (log 1/C) of a large series of phenols against L1210 leukaemia cells was modelled using physicochemical parameters other than conventional electronic and steric parameters. Attempts have also been made to examine need or otherwise of the hydrophobic parameter, log P, in such studies. The results have shown that contribution of log P in modelling log 1/C is favourable.     

On the topological evidences for modelling lipophilicity

Topological evidences for modelling lipophilicity of a large series of diversed compounds have been provided on the basis of distance-based topological indices. A pool of topological indices along with indicator parameters related to the type of the compounds present in the set of 140 compounds were used for this purpose. The results have shown that topology as well as the type of compounds are the responsible parameters for modelling lipophilicity.     

QSAR study on solubility of alkanes in water and their partition coefficients in different solvent systems using PI index

The aqueous solubility (S(w)) of liquids and solids, expressed as log S(w) as well as their partition coefficients in different solvent systems viz. P(oct) (partition coefficient in octanol-water), P(16) (partition coefficient in water-hexadecane), P(alk) (partition coefficient in water-alkane), and P(cyc) (partition coefficient in water-cyclohexane), and aqueous solubility (S(w)) have been estimated using the PI (Padmakar-Ivan) index and the results compared with those obtained using the widely used Wiener index (W). Regression analysis of the data using n-alkanes show that the PI index gives better results than the W index.     

QSAR studies on the activation of the human carbonic anhydrase cytosolic isoforms I and II and secretory isozyme VI with amino acids and amines

The first QSAR study on the activation of the human secretory isoform of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1), CA VI, with a series of amines and amino acids is reported. A large set of topological indices have been used to obtain several tri-/tetra-parametric models. We compared the CA VI activating QSAR models with those calculated for activation of the cytosolic human isozymes hCA I and hCA II. In addition, the effect of D- and L-amino acids as activators of hCA I, hCA II and of hCA VI as compared to those of structurally related biogenic amines was investigated for obtaining statistically significant and predictive QSAR equations. The obtained models are discussed using a variety of statistical parameters. The best models were obtained for hCA II activation, followed by hCA I, whereas the QSAR models for the activation of hCA VI were statistically weaker.     

A novel method of estimation of lipophilicity using distance-based topological indices: dominating role of equalized electronegativity

Attempt is made to propose yet another method of estimating lipophilicity of a heterogeneous set of 223 compounds. The method is based on the use of equalized electronegativity along with topological indices. It was observed that excellent results are obtained in multiparametric regression upon introduction of indicator parameters. The results are discussed critically on the basis various statistical parameters.     

A microsatellite-based consensus linkage map for species of Eucalyptus and a novel set of 230 microsatellite markers for the genus

Background  

Eucalypts are the most widely planted hardwood trees in the world occupying globally more than 18 million hectares as an important source of carbon neutral renewable energy and raw material for pulp, paper and solid wood. Quantitative Trait Loci (QTLs) in Eucalyptus have been localized on pedigree-specific RAPD or AFLP maps seriously limiting the value of such QTL mapping efforts for molecular breeding. The availability of a genus-wide genetic map with transferable microsatellite markers has become a must for the effective advancement of genomic undertakings. This report describes the development of a novel set of 230 EMBRA microsatellites, the construction of the first comprehensive microsatellite-based consensus linkage map for Eucalyptus and the consolidation of existing linkage information for other microsatellites and candidate genes mapped in other species of the genus.     

Novel estimation of lipophilic behaviour of polychlorinated biphenyls

A novel method has been developed for the estimation of lipophilic behaviour of polychlorinated biphenyls (PCBs) using the recently introduced Padmakar-Ivan (PI) index. The results obtained are compared with the earlier reported Abraham method. The statistical analyses showed that the proposed method based on the PI index is quite useful.