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M. Duttachoudhury ¹, P. Nandy ¹, S. K. Biswas ¹, P. Chakrabarty ¹

Affiliations
1 Department of Chemistry, Bose Institute, Calcutta-700 009, IN

Abstract

Turbidimetric assay study of agglutination induced by lectin RCA₁, in erythrocyte ghost membranes of several vertebrates and in the liposomes of their polar lipid isolates, demonstrates that glycolipid is one of the major receptors of lectin RCA₁, in all these systems. The study also shows that Mg²⁺, a divalent metal ion enhances this agglutination. whereas the effect of Ca²⁺ is not so significant in majority of the cases. Reversal of agglutination is studied after addition of galactose to the assay mixture.

Keywords

Glycolipid, RCA, Agglutination, Erythrocyte Ghost, Liposome.

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J. J. Ghosh ¹, A. K. Ghosh ², M. Dattachoudhury ², P. Chakrabarti ³, R. Basu ², P. Nandy ²

Affiliations
1 Biochemistry Department, Calcutta University, Calcutta - 700 019, IN
2 Physics Department, Jadavpur University, Calcutta - 700 032, IN
3 Chemistry Department, Bose Institute, Calcutta - 700 009, IN

Abstract

The Lipid perturbation hypothesis of the mechanism of psychoactivity of Δ⁹-tetrahydrocannabinol (THC) is already established and the morphological alteration of rat brain synaptosomal membrane induced by high THC concentration has been reported. But how the change in lipid ordering is related to the morphological change is not yet fully realised. Using an excimer-forming fluorescent probe, pyrene as the reporter molecule, we have studied for the first time, the effect of high dose of this drug on the lipid ordering of rat brain synaptosomal membrane whose THC absorption tendency is very high. Our result shows that below the drug concentration of 1.75 × 10^-2 mg/mg of protein the membrane is less ordered and above this concentration at 3.5 × 10^-2 mg/mg of protein it is more ordered. This indicates that change in lipid ordering is the preincidence of the morphological-damage of synaptosomal membrane in the molecular level and the drug concentration needed for the alteration of membrane ordering is much lower than that needed for the microscopic morphological alteration.

Keywords

Synaptosome, Lipid Ordering, Δ⁹-Tetrahydrocannabinol, Morphological Alteration.

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S. De ¹, R. Basu ¹, D. Saha ¹, S. Das ¹, P. Nandy ¹

Affiliations
1 Physics Department, Jadavpur University, Calcutta 700 032, IN

Abstract

The groundwater arsenic contamination in Bangladesh is a phenomenon of surface ero- sion, transportation and deposition in the form of Delta and ∼lood Plain. While dealing with such geomorphological units like Tableland, Flood Plain, Delta and Hill Tract in Bangladesh, we have found the possibility of having huge arsenic contaminattion free groundwater reservoir in selected areas in Bangladesh. The results presented are the outcome of our last 5 years, field survey analysing for arsenic of water of twentyfive thousand eight hundred ninetyseven hand tubewells in sixtyfour districts of Bangladesh comprising four existing geomorphological regions (a) Deltaic region (including coastal region), (b) Flood Plain, (c) Tableland and (d) Hill Tract. In this report, we will highlight (1) the area in Bangladesh where groundwater is not arsenic contaminated and the' possibility to use shallow hand tubewells as potential groundwater resource for drinking purpose and (2) arsenic contaminations scenario of deep tubewells (above 100 meters) all over Bangladesh and suitable depth in arsenic contaminated area to get safe water.

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S. De ¹, R. Basu ¹, A. K. Ghosh ¹, P. Nandy ¹

Affiliations
1 Physics Department, Jadavpur University, Calcutta 700 032, IN

Abstract

The action of drugs an living systems is a membrane-based process. Their interaction at the membrane surface/interior and transport through it induces a change in the physical properties of the membrane, of which fluidity is among the most important ones. The lipophilic drugs can affect this fluidity directly through their incorporation into the lipid matrix, whereas the action of the hydrophilic drugs is confined mostly at the membrane-water interface. Using the liposomal membranes of dipalmitoyl phosphatidyl choline, a comparative study of the effect of a hydrophilic drug, chloroquine sulphate, and a lipophilic drug, hydrocortisone, on the membrane fluidity, measured in terms of anisotropy, is presented. From the membrane anisotropy-temperature curve, the associated enthalpy change has been calculated. Results show that the two drugs affect the membrane order in two different ways, indicating that there is a difference in the interaction of these two drugs with the liposomal membrane at the molecular level.

Keywords

Anisotropy, Enthalpy Change, Fluorescence Polarization, Phase Transition.

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S. De ¹, R. Basu ², D. Ghosh ³, S. Manna ³, P. Nandy ³

Affiliations
1 Department of Physics, Dinabandhu Mahavidyalaya, Bongaon, W. B. 743 235, IN
2 Department of Physics, Jogamaya Devi College, Kolkata 700 026, IN
3 Department of Physics, Jadavpur University, Kolkata 700 032, IN

Abstract

We present here the response of a lipid water dispersion to an applied ac field. The electrical study of the system shows that the conductance increases with the applied bias. However with increase in the frequency of the signal the variation of conductance is less pronounced. To explain the variation of the conductance at various frequencies, we have employed the effective medium approach. The results match with the experimental values to a good approximation.

Keywords

Nonlinearity, Effective Medium Approximation, Lipid.

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