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.     

Standardization of parameters for the mycobacillin synthetase activity

An effective method of preparation involving sonication was developed for cell-free mycobacillin synthetase fromBacillus subtilis. The enzyme showed optimum activity at a buffer concentration of 50 mM (Tris-HCl) and pH 7.5. ATP and Mg²⁺ which were essential for synthesis showed an optimum requirement at a ratio of 1∶1. The synthetase was markedly inhibited by ADP whereas AMP was without any effect. ATP or ATP-generating system could not be replaced by GTP, UTP or CTP. Co²⁺ and Mn²⁺ could to some extent substitute Mg²⁺. Mercapto reagents inhibited the antibiotic synthesis. Exogenous addition of pantothenic acid had no effect.     

Characterization of nuclear phosphoprotein phosphatases from goat testis

Two nuclear phosphoprotein phosphatases (PPases I and II) that cause dephosphorylation of [32P]histone, have been partially purified from goat testis. The enzymic activity is associated with nucleoplasm and chromatin. PPase I is markedly stimulated (approx. 200-600%) by Mg2+ or Mn2+ (1 mM) whereas Ca2+ (1 mM) causes slight stimulation (approx. 35%) of the enzyme. On the contrary, PPase II is only slightly activated (20-40%) by these metal ions (5 mM). Both the phosphoprotein phosphatase isoenzymes are maximally active at pH 6-7. PPases I and II are strongly inhibited (approx. 60-100%) by ZnCl2 (1 mM), P1 (5 mM) and thiol reagents. NaF (5 mM) inhibits (approx. 40%) specifically the activity of PPase I rather than PPase II. PPases are strongly inhibited by relatively high concentration of NaCl (0.4 M), isoenzyme II being more sensitive (approx. 80%) than isoenzyme I (approx. 50%). In addition to histones, both the isoenzymes can as well cause dephosphorylation of protamine, casein, and testicular nuclear proteins. Enzymic characteristics of the testicular nuclear PPases are clearly different from those of the cytosolic enzyme previously characterized.     

Role of ATP and enzyme-bound nascent peptides in the control of elongation for mycobacillin synthesis.

The presence of a Zn2+-dependent acid p-nitrophenyl phosphatase (EC 3.1.3.2) in bovine liver was described. The enzyme was purified to apparent homogeneity and migrates as a single band during electrophoresis on polyacrylamide gel. The enzyme requires Zn2+ ions for catalytic activity, other bivalent cations have little or no effect. The enzyme, of Mr 118,000, optimum pH 6-6.2 and pI 7.4-7.5, was inhibited by EDTA, tartrate, adenine and ATP, but not by fluoride. The common phosphate esters are poor substrates for the enzyme, which hydrolyses preferentially p-nitrophenyl phosphate and o-carboxyphenyl phosphate. The Zn2+-dependent acid p-nitrophenyl phosphatase of bovine liver was different from the high-Mr acid phosphatases previously detected in mammalian tissues.     

Studies on the partial structure of the O-antigen of Vibrio cholera Ogawa G-2102

Detailed information was obtained regarding the partial structure of the lipopolysaccharide (LPS), containing glucose, glucuronic acid, 2-amino-2-deoxy-glucose, L-glycero-D-gluco-heptose, and small proportions of L-glycero-D-manno-heptose, mannose, and galactose, isolated from Vibrio cholera Ogawa G-2102. Structures of three oligosaccharides were determined. Results of deamination experiments established the sequence of the linkages between the amino sugar and heptose residues in the O-antigenic polysaccharide.     

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.