Purification and characterisation of an inducible β-galactosidase from Corynebacterium murisepticum

The -galactosidase (EC 3.2.1.32) of Corynebacterium murisepticum (inducible by lactose and galactose) was purified by successive column chromatography on Sephadex G-200, DEAE-Sephadex A-50 and DEAE-cellulose (DE52). The enzyme was found to be a dimer of identical subunits of molecular mass 100,000 daltons. The K _m values of the enzyme for the substrates lactose and o-nitrophenyl--d-galactopyranoside (ONPG) are 16.7 mM and 4.4 mM, respectively, indicating, its low affinity for the substrates. The Ouchterlony immunodiffusion method exhibited immunological homogeneity of the enzyme preparation. The catalytic site of the enzyme does not take part in antigen-antibody reaction.     

Designing a Soluble Near Full-length HIV-1 gp41 Trimer

The HIV-1 envelope spike is a trimer of heterodimers composed of an external glycoprotein gp120 and a transmembrane glycoprotein gp41. gp120 initiates virus entry by binding to host receptors, whereas gp41 mediates fusion between viral and host membranes. Although the basic pathway of HIV-1 entry has been extensively studied, the detailed mechanism is still poorly understood. Design of gp41 recombinants that mimic key intermediates is essential to elucidate the mechanism as well as to develop potent therapeutics and vaccines. Here, using molecular genetics and biochemical approaches, a series of hypotheses was tested to overcome the extreme hydrophobicity of HIV-1 gp41 and design a soluble near full-length gp41 trimer. The two long heptad repeat helices HR1 and HR2 of gp41 ectodomain were mutated to disrupt intramolecular HR1-HR2 interactions but not intermolecular HR1-HR1 interactions. This resulted in reduced aggregation and improved solubility. Attachment of a 27-amino acid foldon at the C terminus and slow refolding channeled gp41 into trimers. The trimers appear to be stabilized in a prehairpin-like structure, as evident from binding of a HR2 peptide to exposed HR1 grooves, lack of binding to hexa-helical bundle-specific NC-1 mAb, and inhibition of virus neutralization by broadly neutralizing antibodies 2F5 and 4E10. Fusion to T4 small outer capsid protein, Soc, allowed display of gp41 trimers on the phage nanoparticle. These approaches for the first time led to the design of a soluble gp41 trimer containing both the fusion peptide and the cytoplasmic domain, providing insights into the mechanism of entry and development of gp41-based HIV-1 vaccines.     

Habitat distribution modelling and reinforcement of Elaeocarpus serratus L. - A threatened tree species of Assam,India for improvement of its conservation status

Elaeocarpus serratus L., commonly known as ‘rudraksh’ referred in the Ayurveda as a wonderful plant for strengthening body constitutions, has been recognized as a threatened plant of Assam, India. Traditionally, rudraksh beads, its bark and leaves are used to cure various ailments like stress, anxiety, depression, nerve pain, epilepsy, migraine, lack of concentration, asthma, hypertension, arthritis and liver diseases. The population stock of the species has been depleting very fast in its natural habitat due to rapid habitat fragmentation and changing climate altering the structural and functional integrity of the plant. Hence, conservation of E. serratus L. with proper scientific investigation to prevent from extinction in its wild habitat is urgently needed. The present study was emphasized with the specific objectives to study the distribution and population status, predication of suitable sites through ENM, standardization of macropropagation methods and reinforcement/reintroduction into the suitable wild habitat to improve conservation status. In the present investigation E. serratus L. was reported in few locations of Assam and Arunachal Pradesh with population sizes of mean density, frequency of occurrence and abundance in relation to other associated species as 0.333, 13.922 and 2.215 respectively. For improving the conservation status, potential area and habitat for reinforcement was predicted using Maximum Entropy (MaxEnt) distribution modelling algorithm. Subsequently, macropropagation protocol was standardized through seed germination and air-layering; saplings were raised and 1050 saplings were reintroduced to the wild habitats selected on the basis of ecological niche modelling. Survival rate was found significantly high as 68%, suggesting that our approach is effective for changing population status and to conserve the plant.     

Liposome-stabilized oil-in-water emulsions as adjuvants: increased emulsion stability promotes induction of cytotoxic T lymphocytes against an HIV envelope antigen

Protective or therapeutic immunity against HIV infection is currently believed to require both antibody and CTL responses against the envelope protein. In the present study, the adjuvant activity of a unique oil-in-water emulsion, in which liposomes containing lipid A (LA) and encapsulated antigen served as the emulsifying agent, was examined in mice using oligomeric gp140 (ogp140) derived from the HIV-1 envelope as the antigen. Emulsions rendered either highly stable or unstable by altering the ratio of liposomes to oil were used to examine the effect of stability of the emulsion on adjuvant activity. Stable and unstable emulsions had similar potencies for inducing both IgG antibodies to ogp140 and antigen-specific T-lymphocyte proliferation. Stable emulsions, but not unstable emulsions, induced antigen-specific CTL responses, possibly because of the depot effect of the stable emulsions. Furthermore, stable emulsions induced lower IgG2a/IgG1 ratios than the unstable emulsions. We conclude that stable liposomal oil-in-water emulsions provide an effective means of obtaining both antibody and CTL responses against an HIV envelope antigen.     

Suggestive evidence of association of C-159T functional polymorphism of the <Emphasis Type="Italic">CD14</Emphasis> gene with atopic asthma in northern and northwestern Indian populations

CD14 is a lipopolysaccharide receptor known to be an important modulator of Th1–Th2 response during early childhood. Genetic association studies of the CD14 gene with asthma and atopic disorders have shown positive as well as negative results in different ethnic populations. The aim of this study was to test for association of C-159T functional promoter polymorphism with atopic asthma and serum IgE levels in northern and northwestern Indian populations. DNA was assayed for the CD14 C-159T polymorphism in a case-control study involving atopic asthmatics (n=187) and healthy normal controls (n=227), and in a family-based association study of 106 trios. The case-control study showed an association at the genotypic (P=0.0146) as well as the allelic level (P=0.0048). Moreover, we observed a deviation of allelic transmission from random proportions (P=0.024) in the transmission disequilibrium test analysis. When we analyzed our results for serum total IgE levels, against this polymorphism, we observed a difference at the genotypic (P=0.0026) as well as at the allelic level (P=0.0016) in a case-control study, whereas no association in the quantitative transmission disequilibrium test analysis was obtained. These findings provide suggestive evidence of association of the CD14 gene locus with atopic asthma in northern and northwestern Indian populations.     

Trace Element Studies on Tinospora cordifolia (Menispermaceae), Ocimum sanctum (Lamiaceae), Moringa oleifera (Moringaceae), and Phyllanthus niruri (Euphorbiaceae) Using PIXE

Traditionally, Tinospora cordifolia (Willd.) Hook. F. & Thomson (Menispermaceae), Ocimum sanctum L. (Lamiaceae), Moringa oleifera Lam. (Moringaceae), and Phyllanthus niruri L. (Euphorbiaceae) are some of the commonly used medicinal plants in India for curing ailments ranging from common cold, skin diseases, and dental infections to major disorders like diabetes, hypertension, jaundice, rheumatism, etc. To understand and correlate their medicinal use, trace element studies on the aqueous extract of these medicinal plants have been carried out using particle-induced X-ray emission technique. A 2-MeV proton beam was used to identify and characterize major and minor elements namely Cl, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, and Sr in them. Results have revealed that these elements are present in varying concentrations in the selected plants. Notable results include very high concentrations of Cl, K, and Ca in all the leaf samples, appreciable levels of Mn in all plants, high Zn content in T. cordifolia, and the aqueous extract of Moringa leaves compared to others and relative higher concentrations of Cr in all the plants.     

Role of K(ATP) channels in protection against neuronal excitatory insults

ATP-sensitive K⁺ (K_ATP) channels that are gated by intracellular ATP/ADP concentrations are a unique subtype of potassium channels and play an essential role in coupling intracellular metabolic events to electrical activity. Opening of K_ATP channels during energy deficits in the CNS induces efflux of potassium ions and in turn hyperpolarizes neurons. Thus, activation of K_ATP channels is thought to be able to counteract excitatory insults and protect against neuronal death. In this review, we bring together recent studies about what kinds of molecules are needed to build and regulate arrays of K_ATP channel functions in the CNS neurons. We propose a model to explain how K_ATP channel activation regulates glutamate release from the pre-synaptic terminals and how this regulation protects against ischemic neuronal injury and epilepsy.