GABA agonists and neurotransmitters metabolizing enzymes in steroid-primed OVX rats

The effect of intraventricular (IVT) administration of GABAA receptor agonist muscimol and GABAB receptor agonist, baclofen was examined on the activity of acetylcholinesterase (AChE), monoamine oxidase (MAO) and Na+, K+-ATPase in discrete areas of brain from estrogen-progesterone primed ovariectomized rats. AChE enzyme activity was increased in two subcellular fractions (soluble and total particulate) studied, with statistically significant changes in cerebral hemispheres (CH), cerebellum (CB), thalamus (TH) and hypothalamus (HT), Na+, K+-ATPase enzyme activity was decreased in both these fractions. MAO activity increased significantly in CH, TH and HT. The presented results suggest a functional relationship between GABAergic (inhibitory), cholinergic and monoaminergic (excitatory) systems by affecting the rate of degradation of the excitatory neurotransmitters and Na+, K+-ATPase. (Mol Cell Biochem 167: 107-111, 1997)     

Hydroxylation of Salicylate and Phenylalanine as Assays for Hydroxyl Radicals: a Cautionary Note Visited for the Third Time

Hydroxylation of salicylate to2, 3- and2, 5-dihydroxy-benzoates (DHBs) is widely used as an index of hydroxyl radical (OH) formation in vivo and in vitro. Several recent studies indicate that peroxynitrite can lead to generation of DHBs from salicylate and it is uncertain as to whether or not OH' is involved. A similar problem may occur in the use of phenylalanine as an OH' detector. Hence formation of hydroxylation products from salicylate (or phenylalanine) may not in itself be a definitive index of OH' generation, especially in cases where such generation in physiological systems is decreased by inhibitors of nitric oxide syn-thase. Determination of salicylate (or phenylalanine) nitration products can allow distinction between peroxynitrite-dependent aromatic hydroxylation and that involving “real” OH.     

Cloning and partial characterization of the putative rifamycin biosynthetic gene cluster from the actinomycete Amycolatopsis mediterranei DSM 46095.

The actinomycete Amycolatopsis mediterranei produces the commercially and medically important polyketide antibiotic rifamycin, which is widely used against mycobacterial infections. The rifamycin biosynthetic (rif) gene cluster has been isolated, cloned and characterized from A. mediterranei S699 and A. mediterranei LBGA 3136. However, there are several other strains of A. mediterranei which also produce rifamycins. In order to detect the variability in the rif gene cluster among these strains, several strains were screened by PCR amplification using oligonucleotide primers based on the published DNA sequence of the rif gene cluster and by using dEBS II (second component of deoxy-erythronolide biosynthase gene) as a gene probe. Out of eight strains of A. mediterranei selected for the study, seven of them showed the expected amplification of the DNA fragments whereas the amplified DNA pattern was different in strain A. mediterranei DSM 46095. This strain also showed striking differences in the banding pattern obtained after hybridization of its genomic DNA against the dEBS II probe. Initial cloning and characterization of the 4-kb DNA fragment from the strain DSM 46095, representing a part of the putative rifamycin biosynthetic cluster, revealed nearly 10% and 8% differences in the DNA and amino acid sequence, respectively, as compared to that of A. mediterranei S699 and A. mediterranei LBGA 3136. The entire rif gene cluster was later cloned on two cosmids from A. mediterranei DSM 46095. Based on the partial sequence analysis of the cluster and sequence comparison with the published sequence, it was deduced that among eight strains of A. mediterranei, only A. mediterranei DSM 46095 carries a novel rifamycin biosynthetic gene cluster.     

Regional effects of ageing on Na+,K(+)-ATPase activity in rat brain and correlation with multiple unit action potentials and lipid peroxidation.

Effects of ageing on Na+,K(+)-ATPase activity in crude synaptosomal fractions from the rat brain parietal cortex, hippocampus, striatum and thalamus has been studied. From 12 months to 24 months, a progressive decline in enzyme activity in the parietal cortex, hippocampus and striatum was found which correlated with increase in lipid peroxidation in the three brain regions. In the thalamus, ageing did not affect the enzyme activity and lipid peroxidation. Age-related decline in multiple unit action potentials was also observed in two brain regions, viz. hippocampus and parietal cortex. Statistical correlations calculated by Pearson's correlation coefficient showed that decline in Na+,K(+)-ATPase activity correlated to decline in multiple unit action potentials. There was rise in lipid peroxidation also and the data indicate that age-related changes in lipid peroxidation and Na+,K(+)-ATPase activity contribute to the deterioration of electrophysiological activity.     

Human platelets contain a novel 47 kDa thiol-oxidase having affinity for genomic sterol-regulatory sequence

The present study provides evidence to support that human platelets possess a 47 kDa dual functional molecule having thiol-oxidase activity as well as high affinity for the SRE sequence in the human genome. On the basis of these as well as earlier results, we propose that Receptor 'C_k' dependent regulation of this dual functional 47 kDa molecule may provide a mechanism for the maintenance of cellular cholesterol homeostasis. Further, this mechanism nay also explain the molecular basis of cholesterol-feedback lesion observed under premalignant conditions.     

Gibberellic acid and kinetin partially reverse the effect of water stress on germination and seedling growth in chickpea

The percent germination and seedling growth of chickpea (Cicer arietinum L. cv. PBG-1) decreased with increasing concentrations of exogenous polyethylene glycol 6000 (PEG). With 15% PEG in the growth medium germination was only 33% while with 10% PEG it was 58% as compared to 93% in control. Addition of gibberellic acid (GA₃) and kinetin to medium containing 10% PEG increased the germination and seedling growth and the effect was maximum with 6 µM GA₃ which was a better inducer of growth and germination under reduced water potential than kinetin. However, indole acetic acid (IAA) inhibited germination and growth of stressed seedlings. The activity of amylase in cotyledons under stress was significantly increased with GA₃ while kinetin and IAA were less effective. Gibberellic acid also enhanced the mobilization of starch from cotyledons of stressed seedlings resulting in low starch levels in cotyledons compared with stressed seedlings.     

Budding and fission yeast casein kinase I isoforms have dual-specificity protein kinase activity.

We have examined the activity and substrate specificity of the Saccharomyces cerevisiae Hrr25p and the Schizosaccharomyces pombe Hhp1, Hhp2, and Cki1 protein kinase isoforms. These four gene products are isotypes of casein kinase I (CKI), and the sequence of these protein kinases predicts that they are protein serine/threonine kinases. However, each of these four protein kinases, when expressed in Escherichia coli in an active form, was recognized by anti-phosphotyrosine antibodies. Phosphoamino acid analysis of 32P-labeled proteins showed phosphorylation on serine, threonine, and tyrosine residues. The E. coli produced forms of Hhp1, Hhp2, and Cki1 were autophosphorylated on tyrosine, and both Hhp1 and Hhp2 were capable of phosphorylating the tyrosine-protein kinase synthetic peptide substrate polymer poly-E4Y1. Immune complex protein kinases assays from S. pombe cells showed that Hhp1-containing precipitates were associated with a protein-tyrosine kinase activity, and the Hhp1 present in these immunoprecipitates was phosphorylated on tyrosine residues. Although dephosphorylation of Hhp1 and Hhp2 by Ser/Thr phosphatase had little effect on the specific activity, tyrosine dephosphorylation of Hhp1 and Hhp2 caused a 1.8-to 3.1-fold increase in the Km for poly-E4Y1 and casein. These data demonstrate that four different CKI isoforms from two different yeasts are capable of protein-tyrosine kinase activity and encode dual-specificity protein kinases.     

Laboratory and field scale bioremediation of hexachlorocyclohexane (HCH) contaminated soils by means of bioaugmentation and biostimulation

Hexachlorocyclohexane (HCH) contaminated soils were treated for a period of up to 64 days in situ (HCH dumpsite, Lucknow) and ex situ (University of Delhi) in line with three bioremediation approaches. The first approach, biostimulation, involved addition of ammonium phosphate and molasses, while the second approach, bioaugmentation, involved addition of a microbial consortium consisting of a group of HCH-degrading sphingomonads that were isolated from HCH contaminated sites. The third approach involved a combination of biostimulation and bioaugmentation. The efficiency of the consortium was investigated in laboratory scale experiments, in a pot scale study, and in a full-scale field trial. It turned out that the approach of combining biostimulation and bioaugmentation was most effective in achieving reduction in the levels of α- and β-HCH and that the application of a bacterial consortium as compared to the action of a single HCH-degrading bacterial strain was more successful. Although further degradation of β- and δ-tetrachlorocyclohexane-1,4-diol, the terminal metabolites of β- and δ-HCH, respectively, did not occur by the strains comprising the consortium, these metabolites turned out to be less toxic than the parental HCH isomers.     

Aerial pollen diversity in Punjab and their clinical significance in allergic diseases

The present study has been carried out to assess the allergenicity of dominant pollen types from the atmosphere of nine districts of the state of Punjab, India. During the study period (2012–2014), 30 different kinds of pollens belonging to 17 families were recorded. Antigenic extract of thirteen pollen types were selected for skin prick tests (SPT). The allergenic pollens selected for the present study belong to families: Asteraceae, Amaranthaceae, Brassicaceae, Cannabaceae, Chenopodiaceae, Meliaceae, Moraceae, Myrtaceae and Xanthorrhoeaceae. Total 165 sensitized patients having diagnosed with bronchoprovocation test were selected for SPT. Diagnostic tests were performed in ENT department, Rajindra hospital Patiala, and SPT were done in the clinic of Dr. H.S. Bedi at Patiala. Antigenic reactivity (3+ to above) to various allergens varied from 2.4 to 9.09 %. Patients showed maximum allergenic sensitivity to Parthenium hystrophorus (9.09 %) followed by Morus alba (8.48 %), Amaranthus spinosus (7.87 %) and Ageratum sp. (6.06 %). Least reactivity was shown by Brassica compestris and Eucalyptus sp. (2.4 %).