Model for bidirectional movement of cytoplasmic dynein.

Cytoplasmic dynein exhibits a directional processive movement on microtubule filaments and is known to move in steps of varying length based on the number of ATP molecules bound to it and the load that it carries. It is experimentally observed that dynein takes occasional backward steps and the frequency of such backward steps increases as the load approaches the stall force. Using a stochastic process model, we investigate the bidirectional movement of single head of a dynein motor. The probability for backward step is implemented based on fluctuation theorem of non-equilibrium statistical mechanics. We find that the movement of dynein motor is characterized with negative velocity implying backward motion beyond stall force. We observe that the motor moves backward for super stall forces by hydrolyzing the ATP exactly the same way as it does while moving forward for sub-stall forces. Movement of dynein is also simulated using a kinetic Monte Carlo method and the simulated velocities are in good agreement with velocities obtained using a stochastic rate equation model.

Amrita Bindu--an antioxidant inducer therapy in asthma children.

Studies all over the world on the therapeutic use of antioxidants as supplements has revealed their capacity to control inflammatory processes. Amrita Bindu an Ayurvedic health food supplement has already shown to be an antioxidant inducer and to combat free radical-mediated tissue damage studied in rats. Amrita Bindu is a salt-spice herbal mixture designed for positive health. It was tested as a supplement to therapy for a period of 12 months in 36 children suffering from asthma. Asthma is a chronic inflammatory disease with excessive free radical generation in lungs and blood cells. The patients were followed up by monitoring their clinical conditions, therapeutic doses of anti-asthmatic drugs, free radical generation, lipid peroxidation (LPO) and antioxidants in blood. At the end of 3 months of Amrita Bindu supplementation, the patients had stopped all anti-asthmatic medications and were free from attacks of asthma.

Estimation of different degrees of provocation by DEC (diethyl carbamazine citrate) medication in bancroftian filariasis in Vellore, Tamilnadu.

DEC in general has the power to bringout the filarial worms into the peripheral blood when administered. The provocative effect was observed in 86.8% of the mf positive cases. Optimum provocative effect was noticed in the age group above 12 years and there was no influence on sex. The maximum effect of provocation was seen at 60 min after the administration 2 mg/kg body weight DEC. The mf rate was high in the blood collected after the administration of DEC during day time, than that during night.

Expression of human growth hormone in silkworm larvae through recombinant Bombyx mori nuclear polyhedrosis virus.

We have generated a recombinant Bombyx mori nuclear polyhedrosis virus, vBmhGH, harboring the full length human growth hormone gene (2.4-kb genomic DNA, with four introns and the signal peptide sequences) under the control of the polyhedrin promoter. BmN cells in culture infected with the recombinant virus showed the presence of RNA corresponding to the authentic growth hormone mRNA as well as its incompletely processed precusor. Electrophoretic analysis and immunoprecipitation of proteins of recombinant virus-infected BmN cells revealed the presence of the growth hormone protein. Infection of silkworm larvae with vBmhGH led to the synthesis and efficient secretion of the protein into hemolymph. The recombinant human growth hormone was biologically active in a radioreceptor competition binding assay. The secreted protein was isolated and purified to homogeneity by a single step immunoaffinity chromatography, to a specific activity of 2.4 x 10(4) U/mg. The recombinant hGH retained the immunological and biological properties of the native peptide. We conclude that BmNPV vectors can be used successfully for expressing chromosomal genes harboring multiple introns.

Baculovirus mediated high-level expression of luciferase in silkworm cells and larvae.

Bombyx mori nuclear polyhedrosis virus (BmNPV)-based baculovirus expression system exploits silkworm larvae as an economical alternative to large-scale cell cultures for production of biomolecules. To generate recombinant BmNPV at high frequencies, we have achieved high efficiency transfection of B. mori cells, BmN, through lipofection. Optimal conditions for lipofection were standardized by quantification of the transient expression level of firefly luciferase (luc) reporter gene under control of an immediate early gene promoter of BmNPV. Lipofection was 50-fold and 100-fold more efficient than the calcium phosphate method for transfecting BmN and Sf9 cells, respectively. Lipofection enabled us to generate a recombinant BmNPV (vBmluc), harboring luc under control of the strong polyhedrin promoter. On infection with vBmluc, luciferase was expressed at very high levels, 170 micrograms/10(6) BmN cells or 13 mg/larva. Expression of luciferase in vBmluc-infected larvae was visualized by luminescence emission instantaneously following luciferin injection generating "glowing silkworms".

A dipstick immunobinding enzyme-linked immunosorbent assay for serodiagnosis of hepatitis B and delta virus infections.

A simple, specific and economical dipstick immunobinding enzyme-linked immunosorbent assay (DIA) for detecting hepatitis B surface antigen (HBsAg) and antibodies to hepatitis delta virus (anti-HDV), utilizing cellulose nitrate membrane is described. Screening of 815 serum specimens for HBsAg by DIA and micro ELISA revealed a positivity of 22.69% and 22.94% respectively. In the detection of antibodies to delta antigen, DIA was compared with an indirect immunofluorescence technique using A3 cell line as antigen substrate and a commercial macro ELISA. Of the 143 HBsAg positive sera tested for anti-HDV, 59 (41.25%) were positive by both immunofluorescence and macro ELISA and 61 (42.65%) by DIA. While the positive and negative predictive values of DIA for HBsAg were 100% and 99.6%, for anti-HDV by DIA these were 96.7% and 100% respectively. Based on the simplicity of performance and the economical nature of the test system, DIA is recommended as a diagnostic tool for field surveys and small laboratories in developing countries.