Optimization of some additives to improve protease production under SSF.

In a locally isolated Rhizopus oryzae strain highest-production of protease (388.54/g wheat bran) was observed in presence of Tween-80 and dioctyl sodium sulfosuccinate individually at 40mg/g wheat bran concentration. Under solid state fermentation biotin (0.0025mg/g wheat bran); Ca2+ (0.05mg/g wheat bran) and 1-Naphthyl acetic acid (0.01mg/g wheat bran) also showed some inducing effect on the synthesis of the enzyme protease by solid state fermentation.

Antibiotic resistance--a close look.

The discovery of antibiotic greatly improved the human health care system. But today we are facing the problem of antibiotic resistance due to uncontrolled use of the compound. This can be by passed by controlled use of antibiotic and formulation of newer ones.

A study of aggregation of 9-(dicyano-vinyl)julolidine.

Di(cyano vinyl)julolidine (DCVJ) is a fluorescent probe which has been used to monitor the local mobility of its binding sites on proteins. It shows a concentration dependence of its emission spectrum in water. At higher DCVJ concentrations, a longer wavelength band appears. The latter increases relative to the shorter wavelength band as a function of increased DCVJ concentration. Absorption and excitation spectra indicate that the concentration dependent emission in the longer wavelength is a consequence of association in the ground state and subsequent excimer formation. DCVJ forms two types of complexes with gamma-cyclodextrin, one of which shows the longer wavelength emission band. Analysis of stoichiometry of association also suggests that longer wavelength emission band may be a consequence of association of two molecules of DCVJ in the gamma-cyclodextrin cavity. Possible uses of such excimer formation in biological systems have also been discussed.

A retrospective study on scorpion sting in a pediatric age group in a hospital in Calcutta.

During 1985-1989, in Calcutta Medical College Hospitals, of 152 children of 1-6 year age group admitted with the history of scorpion sting 18 (11.8%) died. Maximum numbers of stings were inflicted in the fingers. Important clinical features recorded were circulatory failure, breathlessness, profuse sweating, vomiting, local oedema and convulsion. Incidences of scorpion stings were much more frequent in the summer and rainy seasons than in the winter season.

Isolation, characterization and biological activities of a toxin from Bacillus megaterium (B-23).

Fungitoxic substance was isolated from the culture filtrate of B. megaterium (B-23). Age of culture and pH of medium influence the fungitoxicity of its culture filtrate. Partially purified toxin was thermolabile, non-dialysable, ethyl acetate soluble, vanillin-sulphuric acid positive and effective within a range of pH 5-9. It exhibited maximum UV absorption at 224 nm. Its melting point was 242 degrees C. The efficacy of this compound was tested on 4 jute parasites namely, C. corchori, C. gloeosporioides, M. roridum and A. citri, of which M. roridum and C. corchori were least and most sensitive to the toxin respectively.

Role of B-ring of colchicine in its binding to Zn(II)-induced tubulinsheets.

Colchicine-tubulin dimer complex, a potent inhibitor of normal microtubule assembly undergoes extensive self-assembly in the presence of 1 × 10–4 Μ zinc sulphate. Polymers assembled from colchicine-tubulin dimer complexes are sensitive to cold. Although colchicine can be accomodated within the polymeric structure, the drug cannot bind to tubulin subunits in the intact polymers. This is evidenced by the fact that (a) the colchicine binding activity of tubulin is lost when allowed to polymerize with zinc sulphate, (b) the loss in colchicine binding could be prevented by preincubation of tubulin with 1 × 10–3 Μ CaCl2 or 1 × 10–5 Μ vinblastine sulphate and finally (c) no loss in colchicine binding activity is found when tubulin is kept at a concentration far below the critical concentration for polymerization. Unlike colchicine, its B-ring analogues desacetamido colchicine (devoid of the B-ring subtituent) and 2-methoxy-5- (2’,3’,4’-trimethoxyphenyl) tropone (devoid of the B-ring) can bind to tubulin subunits in the intact polymers. Thus we conclude that the colchicine binding domain on the tubulin molecule is mostly (if not completely) exposed in the Zn(II)-induced polymers and the B-ring substituent plays a major role in determining the binding ability of a colchicine analogue to tubulin in the intact Zn(II)-induced sheets.

Molecular biology of tubulin: Its interaction with drugs and genomic organization.

Microtubules are ubiquitous cellular structures found in eukaryotic organisms and responsible for a variety of functions. These functions include mitosis, motility, cytoskeletal architecture, intracellular transport and secretion. The major structural component of microtubules is tubulin, a dimeric protein molecule consisting of two similar but nonidentical subunits (α and β) each of about molecular weight 55,000. With the introduction of radioactive colchicine for the first time it has been reported that colchicine binds specifically to tubulin. At this point microtubule research stepped up to a new era linking microtubules with other spindle poisons which are structurally diverse as well as binding at different sites on to the tubulin heterodimer. These antimicrotubular agents have already provided valuable information regarding microtubule-mediated cellular functions and its association and dissociation phenomena. Tubulins appear to be conserved proteins based on in vitro copolymerization and comigration on polyacrylamide gel electrophoretic properties. Further, amino acid sequences of both α and β subunits from a variety of sources also appear to be mostly conserved. The evolutionary conservation of tubulin genes is highly reflected at the nucleic acid level as well. The estimation of the number of genes for tubulin and their organization in a variety of organisms have opened up a new dimension to microtubule and tubulin research. The multigene family for tubulins comprising also pseudogenes is suggestive that more than one gene for each α and β tubulin is functional in the cell. Therefore, it has been speculated that different tubulin gene products contribute to functionally different microtubules at specific stages in cell cycle and cell growth. Heterogeneity in both α and β tubulins has already been established during different stages of development of the cell. Obviously, it reflects that tubulin genes are highly regulated and this regulation might be at the transcriptional and/or translational level. Whatever is the actual control mechanism it appears that cells can detect an enhanced pool of depolymerized subunits and a rapid and specific control in tubulin gene expression at the transcriptional and/or post transcriptional level does occur.