Hydrogen Bonding in Phenol, Water, and Phenol−Water Clusters

Structure, stability, and hydrogen-bonding interaction in phenol, water, and phenol-water clusters have been investigated using ab initio and density functional theoretical (DFT) methods and using various topological features of electron density. Calculated interaction energies at MP2/6-31G level for clusters with similar hydrogen-bonding pattern reveal that intermolecular interaction in phenol clusters is slightly stronger than in water clusters. However, fusion of phenol and water clusters leads to stability that is akin to that of H(2)O clusters. The presence of hydrogen bond critical points (HBCP) and the values of rho(r(c)) and nabla(2)rho(r(c)) at the HBCPs provide an insight into the nature of closed shell interaction in hydrogen-bonded clusters. It is shown that the calculated values of total rho(r(c)) and nabla(2)rho(r(c)) of all the clusters vary linearly with the interaction energy.

Electrophilicity index as a possible descriptor of biological activity

The purpose of this study is to probe the suitability of DFT based chemical reactivity parameter, electrophilicity index as a possible biological activity descriptor in the development of QSAR. Testosterone derivatives with activity described in terms of various biological activity parameters and the estrogen derivatives by relative binding affinity (RBA) values have been selected as model systems. The implications for the ability of electrophilicity to describe the biological activities are discussed. From the results it is possible to observe that electrophilicity index may be suitable to effectively describe the biological activity.

Distribution and fractionation of heavy metals in solid waste from selected sites in the industrial belt of Delhi, India

Solid waste samples were collected from five small-scale industrial sites in the National Capital Territory (NCT) of Delhi. These industrial sites represent the regional spread of the industrial belt in the NCT of Delhi. Solid waste samples were digested using aqua-regia and HF in air tight teflon bombs for the quantitative analysis of heavy metals (Hg, Pb, Cd, Mn, Fe, Ni, Cu and Zn) by GBC model 902 atomic absorption spectrophotometer. Hg was analysed using hydrid generator attachment. Beside this sequential extraction was used to fractionate five heavy metals (Pb, Ni, Cd, Cu and Zn) into six operationally defined phases, viz. water soluble, exchangeable, carbonate-bound, Fe-Mn oxides, organic-bound and residual fractions to ascertain the relative mobility of these metals. The result obtained showed metal concentration to be in the range of Hg 0.42-2.3; Pb 23-530; Cd 014-224; Mn 494-19 964; Fe 35 684-233 119; Ni 192-1534; Cu 3065-10 144 and Zn 116-23 321 (all units in mg kg(-1)) in all the industrial areas studied. The fractionated toxic metals like Pb, Ni and Cd were observed to be in the range of 25-35, 15-50 and 40-50%, respectively, in mobile or bio-available fractions of solid waste. As this waste is often disposed-off by the roadsides, low lying areas, abandoned quarries or in landfill sites which are often not properly planned, thus posing potential risk to ground and surface water quality to millions of people living downstream.

Mesoporous SnO2 synthesized with non-ionic surfactants as an anode material for lithium batteries

Mesoporous tin oxides were successfully prepared with the use of non-ionic surfactants, Pluronic 123 (P-123) and Tetronic 908 (T-908). Surface analysis of SnO2 synthesized with P123 showed an average pore size of approximately 15 nm. The high-resolution transmission electron microscopy and low-angle X-ray diffraction (XRD) measurements also confirmed their mesoporous nature. The X-ray photoelectron spectroscopy and wide-angle XRD studies revealed that these compounds have a casserite-type SnO2 structure. The electrochemical properties of these materials as anodes in lithium batteries showed excellent performance with good reversibility. The first-cycle reversible capacity was 1026 mAh/g for the material synthesized with P123. There was a high first-cycle irreversible capacity for SnO2 synthesized with the use of both non-ionic surfactants. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed to study the electrode kinetics during the lithium insertion process in the first cycle. There was a decrease in the charge-transfer resistance with respect to the discharge potential. The synthesis and structural and electrochemical properties of the mesoporous tin oxides are correlated and discussed in detail.

The angiogenins: an emerging family of ribonuclease related proteins with diverse cellular functions

Angiogenin is a member of the ribonuclease superfamily, which shows an ever expanding collection of molecules being identified and cloned. It was initially isolated from the conditioned medium of cultured tumour cells. Its angiogenic activity appears to be critical for the maintenance and support of tumour growth. Angiogenin also plays a role in a number of non-malignant vasculoproliferative pathological conditions. Along with other related molecules, it has been identified in a wide variety of somatic tissues in adult and embryonic stages of vertebrate development. This suggests that angiogenin and related molecules are likely to play a vital role in normal physiology. Angiogenin is detectable in serum and to date has been implicated as a mitogen for vascular endothelial cells, an immune modulator with suppressive effects on polymorphonuclear leukocytes, an activator of certain protease cascades such as matrix metalloproteases and plasminogen-activated plasmin pathways, as well as an adhesion molecule. However, the role of the angiogenin family in both normal and abnormal physiology and in development will only fully be realised by genetic approaches involving gene deletion.

Nature of distribution of mercury in the sediments of the river Yamuna (tributary of the Ganges), India

Suspended Particulate Matter (SPM), surface (bed sediments) and short length cores of sediments collected from the largest tributary of the river Ganges, namely the river Yamuna, were analysed for total mercury as well as its fractionation in various size and chemical sites in the sediments following standard procedures. Also, attempts were made to determine the vertical distribution in sediments in relation to the recent timescale of a few decades. Our observations indicate that the SPM in general showed higher levels of total mercury compared to the surface sediments while at places the enhancement could be by a factor of 10, say around 25 microg g(-1) in the downstream region that integrates the industrial midstream and agricultural downstream terrain near its confluence with the Ganges. Surface sediments in the upstream direction near the Himalayan foothills and SPM in the lower reaches showed significant high Index of Geoaccumulation (Igeo) as defined by Müller. Size fractionation studies indicate that the finer fraction preferentially showed higher levels of mercury while in the lower reaches of the river, the total mercury is equitably distributed among all size fractions. The proportion of the residual fraction of mercury in relation to mobile fractions, in general decreases downstream towards its confluence with the Ganges river. In sediment cores, the vertical distribution show systematic peaks of mercury indicating that addition of this toxic metal to the aquatic system is in direct proportion to the increase in various types of human activities such as thermal power plants, land use changes (urbanisation) in the midstream region and intensive fertiliser application in lower reaches of this vast river basin.

Fluoride in fractionated soil samples of Ajmer district, Rajasthan

The natural abundance of fluoride in soils of the Ajmer distict, Rajasthan was examined. From undisturbed soil, the top 15 cm of the profile was examined and the soil split into fractions based on sand, silt and clay particle size. Clay contained a high amount of fluoride, whereas sand and silts are enriched with much less fluoride. The relation between the soil fractions in observed clay fraction fluoride content matched groundwater fluoride variation. However, the enrichment of fluoride material extracted from the largest soil fraction had considerably lower amounts of clay relative to that from the smaller fractions.

A study of the interaction of Cr(III) complexes and their selective binding with B-DNA: a molecular modeling approach

Molecular modeling and energy minimisation calculations have been used to investigate the interaction of chromium(III) complexes in different ligand environments with various sequences of B-DNA. The complexes are [Cr(salen)(H(2)O)(2)](+); salen denotes 1, 2 bis-salicylideneaminoethane, [Cr(salprn)(H(2)O)(2)](+); salprn denotes 1, 3 bis- salicylideneaminopropane, [Cr(phen)(3)](3+); phen denotes 1, 10 phenanthroline and [Cr(en)(3)](3+); en denotes ethylenediamine. All the chromium(III) complexes are interacted with the minor groove and major groove of d(AT)(12), d(CGCGAATTCGCG)(2) and d(GC)(12) sequences of DNA. The binding energy and hydrogen bond parameters of DNA-Cr complex adduct in both the groove have been determined using molecular mechanics approach. The binding energy and formation of hydrogen bonds between chromium(III) complex and DNA has shown that all complexes of chromium(III) prefer minor groove interaction as the favourable binding mode.

Methane emissions from a coastal lagoon: Vembanad Lake, West Coast, India

An attempt has been made to estimate methane fluxes from a tropical coastal wetland the Vembanad Lake, a lagoon along the West Coast of India. It has been found that Vembanad Lake contributes significant amount of methane to the atmosphere. Average emissions varied spatially within the lake. Methane emissions were 193.2 +/- 24.5 mg m(-2) h(-1) at Kumaragam (fresh water) as compared to 9.3 +/- 9.6 mgm(-2) h(-1) at Pullot (brackish water) site. Seasonal variation was significant between pre- and post-monsoons. Soil temperature, time of the day, salinity sediment organic carbon, all control the rate of methane emissions from the Vembanad Lake.

Release of soluble ICAM-5, a neuronal adhesion molecule, in acute encephalitis

BACKGROUND

Intercellular adhesion molecule (ICAM)-5 (telencephalin) is an adhesion molecule in telencephalic neurons of the mammalian brain that binds to the leukocyte integrin CD11a/CD18. The authors observed that human cerebral neurons also expressed ICAM-5 and that ICAM-5--mediated neuron--leukocyte binding in cultured hippocampal neurons. This led the authors to examine ICAM-5 expression during clinical CNS inflammation.

METHODS

The authors found, by immunoblotting, a 115-kDa soluble form of ICAM-5 (sICAM-5) cleaved from the membrane-bound (130 kDa) ICAM-5, and established an ELISA assay to measure it. CSF samples of patients with acute encephalitis and MS were studied.

RESULTS

sICAM-5 was increased in encephalitis (320 plus minus 107 ng/mL; n = 25), as compared with patients with MS (128 plus minus 10 ng/mL; n = 16) and control subjects without CNS disease (137 plus minus 6 ng/mL; n = 42) (p < 0.001). The concentration of sICAM-5 correlated with the performance in the immediate recall task (p = 0.013) and with the leukocyte count in the CSF (p = 0.02), especially in cases caused by herpes simplex virus (HSV) (r = 0.94; p = 0.002).

CONCLUSIONS

sICAM-5 is cleaved from CNS into CSF during acute encephalitis, and it may mediate leukocyte--neuron interactions. sICAM-5 release from cerebral neurons may actively regulate immune responses and leukocyte adhesion during microbial neuroinvasion in humans during encephalitis.

Present status of asbestos mining and related health problems in India--a survey

At present in India more than thirty mines are in operation. It produces 2800 tones of asbestos per month (mainly chrysotile and tremolite) and in recent years substantial quantity (-70%) is imported from Canada. The quality of asbestos produced in India is very poor. The mining and milling and other related processes expose the people to cancer and related diseases. Women are more affected by their exposure in processing unit compared to male who are generally working in mines. Direct and indirect employment in asbestos related industry and mine is around 100,000 workers. Latency period (length of the time between exposure and the onset of diseases) in India is estimated to be 20-37 yr. The causes for lung and breathing problem are mainly due to obsolete technology and direct contact with the asbestos products without proper precaution, because in India asbestos are sold without statutory warning. This paper reviews health effects (such as fibrosis, sequelae, bronchogenic cancer, and malignant mesothelioma) on the Indian mine workers caused due to asbestos mining related activities with respect to their present day condition.

Differentiation potential of intestinal mesenchyme and its interaction with epithelial cells: a study using beta-galactosidase-expressing fibroblast lines

Rat intestinal fibroblast lines (F1:G9 and A1:F1) differing in their potential to support intestinal mucosal development were marked with reporter genes to investigate their differentiation potential. The fibroblasts were transfected with plasmids expressing either beta-galactosidase (with or without a nuclear localisation signal) or green fluorescent protein (GFP). Transfection using Tfx50 or Fugene was more efficient than electroporation. The expression of beta-galactosidase was more stable and stronger than GFP. Cells were optimally labelled using the plasmid pL27B-GAL, and sub-clones with a strong and uniform nuclear expression of beta-galactosidase were isolated. These clones expressed beta-galactosidase even after prolonged passage in the absence of selection. The beta-galactosidase tagged lines (F1:G9gal and A1:F1gal) retained the morphological characteristics, viability and differentiation properties of the parental non-transfected lines. In co-culture with a colorectal tumour cell line Caco-2, the F1:G9gal and A1:F1gal cells differed in their morphological organisation but this did not change their expression of smooth muscle alpha-actin.

Truncation of the Mll gene in exon 5 by gene targeting leads to early preimplantation lethality of homozygous embryos

The mixed lineage leukemia gene (MLL) was originally identified through its involvement in reciprocal translocations in leukemias. MLL codes for a large multidomain protein and bears homology to the Drosophila developmental control gene trithorax in two small domains in the amino terminal region, the central zinc finger domain and the carboxy SET domain. Like the Drosophila trx, MLL has also been shown to be a positive regulator of Hox gene expression. We have targeted Mll (the murine homologue of MLL) in exon 5 causing expression of three truncated in-frame Mll transcripts. These transcripts retain all or some of the AT hook motifs and the DMT domain. This mutant allele causes early in vivo preimplantation lethality of homozygous embryos prior to the 2-cell stage. Embryos cultured in vitro progress to the 2-cell stage, but further development is arrested. The heterozygotes exhibit mild skeletal defects as well as defects in some neuroectodermal derivatives.

High-level expression of three members of the murine angiogenin family in Escherichia coli and purification of the recombinant proteins

Angiogenin (Ang) is a small basic protein which belongs to the pancreatic ribonuclease superfamily. It potently induces the formation of new blood vessels and has emerged as a promising anticancer target. Mice possess genes encoding one ortholog (mAng) and three homologs of Ang, designated angiogenin-related protein (mAngrp), angiogenin-3 (mAng-3), and angiogenin-4 (mAng-4). Structural and functional study of these homologs has been hampered by the low yield of protein from the existing heterologous expression system. In the experiments described, we used a pET expression vector to express these proteins in the cytoplasm of Escherichia coli BL21-CodonPlus(DE3)-RIL cells, whereupon substantial amounts of each accumulated in the form of insoluble aggregates. The proteins were renatured using an arginine-assisted procedure and subsequently purified by cation-exchange chromatography and reversed-phase HPLC; each purified protein was shown to be enzymatically active toward tRNA. The yields of pure mAngrp and mAng-3 were 7.6 and 12 mg/liter culture, respectively, representing substantial increases over previously reported experiments. This is also the first report of the expression and purification of mAng-4, obtained here in a yield of 30 mg/liter culture. The ready availability of milligram quantities of these proteins will enable further functional studies and high-resolution structural analyses to be conducted.

Stem cells and the regulation of proliferation, differentiation and patterning in the intestinal epithelium: emerging insights from gene expression patterns, transgenic and gene ablation studies

Tissues that undergo self-renewal such as the skin, the haematopoeitic system and the intestine are all maintained and renewed by a small group of multipotent stem cells. The stem cells of the intestinal epithelium are located in the crypts and give rise to its four main lineages located mainly in the finger like projections- the villi. An increasing number of genes are now being identified as either being necessary for or involved in the maintenance of intestinal stem cells and regulating differentiation along the crypt-villus axis. These developmental regulatory genes include among others, Tcf-4, Cdx-1 Fkh6, HFH11 and Nkx2-3. Other genes such as the integrins, and Indian hedgehog (Ihh) also affect function of the progenitor cells of the intestinal epithelium. This mini-review will focus on the more recent data on expression patterns of genes in the intestinal epithelium and the direct or indirect effects of their ablation on proliferation and differentiation.

Integrated minimally invasive approaches for the treatment of atherosclerotic vascular diseases: Hybrid procedures

Patients may develop simultaneous symptoms of atherosclerotic vascular disease from different arterial beds. A concurrent minimally invasive approach to the management of these clinical situations may be an advantage over conventional surgical procedures. This study describes two separate case series of patients undergoing coronary/peripheral (n = 38) and peripheral/peripheral procedures (n = 10). Technical and clinical success was achieved in all patients. There were two periprocedural complications (retroperitoneal bleed and septicemia) in the coronary/peripheral series and no complications in the peripheral/peripheral series. We also present five case reports to illustrate the utility of hybrid procedures in various clinical settings. This study suggests that the use of simultaneous or sequential minimally invasive procedures appears to be a safe and feasible strategy for the treatment of patients with symptoms from more than one vascular bed. Cathet Cardiovasc Intervent 2001;52:154-161.

Functional expression of a high affinity mammalian hepatic choline/organic cation transporter

Uptake by the liver of the organic cation and essential nutrient choline is required for the hepatic synthesis of phosphatidylcholine. Uptake of other organic cations is also important for the metabolism and secretion of numerous endobiotics and drugs. Although a high affinity mammalian hepatic choline transporter has been kinetically defined, it has not been previously identified. We have developed stable transfectants of BALB/3T3 cells, using a murine member of the organic cation transporter gene family (mOct1/Slc22a1), and used these cells to characterize the transport of the organic cation choline and model organic cation tetraethylammonium (TEA). Functional expression of mOct1/Slc22a1 in BALB/3T3 cells confers the saturable, temperature-dependent uptake of choline with a K(m) of 42 micrometer, and uptake of TEA with a K(m) of 43 micrometer. We subsequently used our cell culture uptake system to kinetically define in HepG2 cells a high affinity choline uptake process, which transports choline with a K(m) similar to that of mOct1/Slc22a1 protein. We also demonstrated that organic cation transport by mOct1/Slc22a1 is inhibited by several organic cations, and that the gene is expressed in the perinatal period, at a time when phosphatidylcholine synthesis increases. We conclude that mOct1/Slc22a1 encodes a high affinity mammalian hepatic choline/organic cation transporter. This transporter may be important for hepatic phosphatidylcholine synthesis, and for the metabolism and secretion of many organic cationic drugs.

IgA nephropathy, the most common cause of glomerulonephritis, is linked to 6q22-23

End-stage renal disease (ESRD) is a major public health problem, affecting 1 in 1,000 individuals and with an annual death rate of 20% despite dialysis treatment. IgA nephropathy (IgAN) is the most common form of glomerulonephritis, a principal cause of ESRD worldwide; it affects up to 1.3% of the population and its pathogenesis is unknown. Kidneys of people with IgAN show deposits of IgA-containing immune complexes with proliferation of the glomerular mesangium (Fig. 1). Typical clinical features include onset before age 40 with haematuria and proteinuria (blood and protein in the urine), and episodes of gross haematuria following mucosal infections are common; 30% of patients develop progressive renal failure. Although not generally considered a hereditary disease, striking ethnic variation in prevalence and familial clustering, along with subclinical renal abnormalities among relatives of IgAN cases, have suggested a heretofore undefined genetic component. By genome-wide analysis of linkage in 30 multiplex IgAN kindreds, we demonstrate linkage of IgAN to 6q22-23 under a dominant model of transmission with incomplete penetrance, with a lod score of 5.6 and 60% of kindreds linked. These findings for the first time indicate the existence of a locus with large effect on development of IgAN and identify the chromosomal location of this disease gene.

Identification of DNA polymorphism in cultivated groundnut using random amplified polymorphic DNA (RAPD) assay

Construction of a genetic linkage map is necessary to apply marker-assisted selection tools in a crop improvement program. Except for the recent studies from two laboratories, most of the previous studies have shown little or no DNA polymorphism in cultivated groundnut (Arachis hypogaea L.). In the present study, 70 selected genotypes, representing variability for several morphological, physiological, and other characters, were studied for polymorphism employing random amplified polymorphic DNA (RAPD) assay with 48 oligonucleotide primers. Of the 48 oligonucleotide primers only 7 (14.6%) yielded polymorphic amplification products. The total number of bands from the 7 primers was 408, of which 27 were polymorphic. Detection of polymorphism in cultivated groundnut opens up the possibility of development of its molecular map by judicious selection of genotypes that show DNA polymorphism. This approach will be useful for developing marker-assisted selection tools for genetic enhancement of groundnut for desirable traits.Key words: Arachis hypogaea L., RAPD, DNA polymorphism, oligonucleotide, random primers.

Identification of DNA polymorphism in cultivated groundnut using random amplified polymorphic DNA (RAPD) assay

Construction of a genetic linkage map is necessary to apply marker-assisted selection tools in a crop improvement program. Except for the recent studies from two laboratories, most of the previous studies have shown little or no DNA polymorphism in cultivated groundnut (Arachis hypogaea L.). In the present study, 70 selected genotypes, representing variability for several morphological, physiological, and other characters, were studied for polymorphism employing random amplified polymorphic DNA (RAPD) assay with 48 oligonucleotide primers. Of the 48 oligonucleotide primers only 7 (14.6%) yielded polymorphic amplification products. The total number of bands from the 7 primers was 408, of which 27 were polymorphic. Detection of polymorphism in cultivated groundnut opens up the possibility of development of its molecular map by judicious selection of genotypes that show DNA polymorphism. This approach will be useful for developing marker-assisted selection tools for genetic enhancement of groundnut for desirable traits.

Interaction of DNA with [Cr(Schiff base)(H(2)O)(2)]ClO(4)

The binding of Schiff base complexes of chromium(III) of the type [Cr(salen)(H(2)O)(2)](+) and [Cr(salprn)(H(2)O)(2)](+), where salen denotes 1,2-bis(salicylideneamino)ethane and salprn denotes 1,3-bis(salicylideneamino)propane to calf thymus DNA has been investigated by absorption, emission, circular dichroism, melting temperature and viscosity measurements. These chromium(III) complexes showed absorption hyperchromicity accompanied by red shift in charge transfer band, fluorescence enhancement, increase in melting temperature, some structural changes in CD spectra and changes in specific viscosity when bound to calf thymus DNA. The binding constant K(b) has been determined from absorption measurements for both the complexes and found to be (2.5+/-0. 4)x10(3) M(-1) for [Cr(salen)(H(2)O)(2)](+) and (1.7+/-0.3)x10(4) M(-1) for [Cr(salprn)(H(2)O)(2)](+). From the binding stoichiometry of DNA-[Cr(salprn)(H(2)O)(2)](+), the number of binding site size has been determined and found to be ten base pairs per bound complex molecule. The chromium(III) complexes also bring about single strand cleavage in plasmid DNA. The experimental results show that the chromium(III) complexes bind to DNA by non-intercalative mode. Major groove binding is the preferred mode of interaction for these Schiff base complexes of chromium(III).

DNA cleavage by a Chromium(III) complex

A new Cr(III) complex with the empirical formula [Cr(Schiff base) (H(2)O)(2)]ClO(4), where the Schiff base is 2, 3-bis¿[(2-hydroxy-4-diethylamino) (phenyl) (methylene)]amino¿2-butenedinitrile has been synthesized and characterized spectroscopically. Binding of this complex to DNA has been studied using UV-visible spectroscopy. The complex has been found to bind to the major groove of DNA with a binding constant, K = (1.3 +/- 0.2) x 10(3) M(-1). The induced CD spectrum of the complex in the presence of DNA is also indicative of major groove binding. Gel electrophoresis of plasmid DNA in the presence of the complex shows that the complex brings about nicking of the DNA.

Chiral high-performance liquid chromatography of N-octyl bicycloheptene dicarboximide and confirmatory studies using liquid chromatography-tandem mass spectrometry and two-dimensional nuclear magnetic resonance spectroscopy

N-Octyl bicycloheptene dicarboximide (MGK 264) has exo and endo diastereomers. Each structure has a chiral center at the nitrogen side chain. Enantioselective separation of MGK 264 was achieved by normal-phase high-performance liquid chromatography (HPLC) using cellulose-based Chiralcel OD column with diode-array and optical rotation detectors. Peaks were isolated with the purpose of identifying their stereochemical structures. Molecular mass of the HPLC peaks and their structural information was determined by liquid chromatography-electrospray tandem mass spectrometry (LC-ES-MS-MS). A two-dimensional nuclear magnetic resonance (NMR) spectroscopic technique was used to establish the structural features. Correlation of the data obtained from chiral separation and NMR facilitated in unambiguous assignment of the HPLC peaks.