Alkaloids of the leaves of Voacanga grandifolia

Besides vobtusine and vobtusine-lactone, deoxyvobtusine was isolated from the leaves of Voacanga grandifolia (Miq. Rolfe. Spectral and chemical evi     

Socioeconomic, demographic and environmental determinants of infant mortality in Nepal

The Nepal Fertility and Family Planning Survey of 1986 demonstrated that demographic variables, previous birth interval and survival of preceding child, still predominated as determinants of infant mortality, particularly in rural areas of Nepal. However, in urban Nepal, where the level of socioeconomic development is higher, an environmental variable, along with previous birth interval and survival of preceding child emerges as important in determining infant mortality. Separate policy measures for child survival prospects in rural and urban Nepal are suggested.     

Correlation between nuclear glucocorticoid receptor levels and casein gene expression in murine mammary gland in vitro

The relationship between nuclear binding of glucocorticoid-receptor complex and casein gene expression was studied in organ culture of the whole mammary gland of the mouse. Pyridoxal 5'-phosphate was used as a modulatory agent for measuring nuclear binding of the receptor complex. Addition of 2 mM and 5mM pyridoxal-5'-P in the medium (Waymouth's MB752/1) resulted in 4- and 12-fold increase of its concentration in the glands incubated with insulin, prolactin, and hydrocortisone. Pyridoxal-5'-P also caused a 52% and 92% inhibition of nuclear binding of [3H]dexamethasone in the glands at 2 mM and 5 mM concentration in the presence of the same hormones in the medium. Corresponding to the reduced nuclear binding of the receptor complex casein mRNA levels, measured by a specific cDNA probe was reduced 86% and over 90% in the glands exposed to 2 mM and 5 mM pyridoxal-5'-P, respectively, in presence of insulin, prolactin, and hydrocortisone in the medium. Withdrawal of pyridoxal-5'-P from the medium restored nuclear binding of the receptor complex near the level of control glands incubated only with the hormones. mRNA casein levels also increased in the gland in the pyridoxal-5'-P-free medium containing the same hormones. This indicates that pyridoxal-5'-P does not alter the specific hormone responsiveness of the mammary cells and its action mediated at the level of the glucocorticoid receptor can influence hormone-inducible expression of the casein genes. Thus, glucocorticoid plays a major role in the multiple hormone regulation of the milk protein gene(s). The findings also suggest that the breast tissue concentration of the vitamin B6 derivative may influence the physiology of lactation in nursing mothers.     

VDAC3 regulates centriole assembly by targeting Mps1 to centrosomes

Centrioles are duplicated during S-phase to generate the two centrosomes that serve as mitotic spindle poles during mitosis. The centrosomal pool of the Mps1 kinase is important for centriole assembly, but how Mps1 is delivered to centrosomes is unknown. Here we have identified a centrosome localization domain within Mps1 and identified the mitochondrial porin VDAC3 as a protein that binds to this region of Mps1. Moreover, we show that VDAC3 is present at the mother centriole and modulates centriole assembly by recruiting Mps1 to centrosomes.     

Two-dimensional gel-based alkaline proteome of the probiotic bacterium Lactobacillus acidophilus NCFM

Lactobacillus acidophilus NCFM (NCFM) is a well-documented probiotic bacterium isolated from human gut. Detailed 2D gel-based NCFM proteomics addressed the so-called alkaline range, i.e., pH 6-11. Proteins were identified in 150 of the 202 spots picked from the Coomassie Brilliant Blue stained 2D gel using MALDI-TOF-MS. The 102 unique gene products among the 150 protein identifications were assigned to different functional categories, and evaluated by considering a calculated distribution of abundance as well as grand average of hydrophobicity values. None of the very few available lactic acid bacteria proteome reference maps included the range of pI >7.0. The present report of such data on the proteome of NCFM fundamentally complements current knowledge on protein profiles limited to the acid and neutral pH range.     

Differential induction of Leishmania donovani bi-subunit topoisomerase I-DNA cleavage complex by selected flavones and camptothecin: activity of flavones against camptothecin-resistant topoisomerase I

Emergence of the bi-subunit topoisomerase I in the kinetoplastid family (Trypanosoma and Leishmania) has brought a new twist in topoisomerase research related to evolution, functional conservation and preferential sensitivities to the specific inhibitors of type IB topoisomerase family. In the present study, we describe that naturally occurring flavones baicalein, luteolin and quercetin are potent inhibitors of the recombinant Leishmania donovani topoisomerase I. These compounds bind to the free enzyme and also intercalate into the DNA at a very high concentration (300 µM) without binding to the minor grove. Here, we show that inhibition of topoisomerase I by these flavones is due to stabilization of topoisomerase I–DNA cleavage complexes, which subsequently inhibit the religation step. Their ability to stabilize the covalent topoisomerase I–DNA complex in vitro and in living cells is similar to that of the known topoisomerase I inhibitor camptothecin (CPT). However, in contrast to CPT, baicalein and luteolin failed to inhibit the religation step when the drugs were added to pre-formed enzyme substrate binary complex. This differential mechanism to induce the stabilization of cleavable complex with topoisomerase I and DNA by these selected flavones and CPT led us to investigate the effect of baicalein and luteolin on CPT-resistant mutant enzyme LdTOP1Δ39LS lacking 1–39 amino acids of the large subunit [B. B. Das, N. Sen, S. B. Dasgupta, A. Ganguly and H. K. Majumder (2005) J. Biol. Chem. 280, 16335–16344]. Baicalein and luteolin stabilize duplex oligonucleotide cleavage with LdTOP1Δ39LS. This observation was further supported by the stabilization of in vivo cleavable complex by baicalein and luteolin with highly CPT-resistant L.donovani strain. Taken together, our data suggest that the interacting amino acid residues of topoisomerase I may be partially overlapping or different for flavones and CPT. This study illuminates new properties of the flavones and provide additional insights into the ligand binding properties of L.donovani topoisomerase I.     

Application of a hybrid biofilter column for the removal of Cr(VI) from aqueous solution using an indigenous bacterial strain Pseudomonas taiwanensis

In the present study, a laboratory-scale biofilter column was designed and fabricated. It was packed with a mixture of coal and compost as a packing medium. The column was enriched with an indigenous bacterial strain Pseudomonas taiwanensis isolated from aerobic mixed culture of Sewage Treatment Plant, BITS-Pilani, Pilani campus. The removal of hexavalent chromium [Cr(VI)] from aqueous solution was investigated in the biofilter column. The entire biofiltration operation was divided into five phases (I to V) for a period of 63 days. Biofilter column was subjected to shock loading conditions for 20 days immediately after 63 days of operation. The maximum removal efficiency of 89.4% was obtained during phase V for Cr(VI) inlet concentration of 40 mg L^?1. During shock loading, maximum removal efficiency was obtained as 90% for 48.5–50 mg L^?1 of initial Cr(VI) concentration. Kinetic parameters of biofiltration process for Cr(VI) removal were also determined by fitting Michaelis-Menten kinetic model with experimental data. The Michaelis-Menten kinetic constants were obtained as 0.258 mg L^?1 min^?1 and 26.83 mg L^?1. It was found that Ottengraf-Van den Oever model with zero-order diffusion limitation fit the experimental data quite well for phases III, IV, and V with coefficient of determination (R²) values .97, .99, and .984, respectively. A possible method for safe disposal of packing medium was also presented in this study.