NISCAIR Online Periodicals Repository Collection: IJBB Vol.46(2) [April 2009]

Antioxidant and cytotoxic activities of Caesalpinia pulcherrima wood

Sun, 29 Mar 2009 22:58:59 GMT

Title: Antioxidant and cytotoxic activities of Caesalpinia pulcherrima wood

Authors: Pawar, C R; Mutha, R E; Landge, A D; Jadhav, R B; Surana, S J

Abstract: Antioxidant and cytotoxic activities of the methanolic and aqueous extracts of Caesalpinia pulcherrima wood were studied in in vitro models. Both extracts exhibited strong antioxidant activity, as evidenced by the low IC₅₀ values in both 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide and superoxide scavenging methods; the values were found to be less or comparable to those of gallic acid, the standard used. To determine the cytotoxic activity, extracts were tested for toxic effects to brine shrimp larvae. In this assay, the methanolic extract had little effect, but aqueous extract was relatively toxic. The antioxidant and cytotoxic activities may be attributed to the total phenolic content in the wood.

Page(s): 198-200

Interactions of bacterial polysaccharides with cationic dyes: Physicochemical studies

Sun, 29 Mar 2009 22:58:59 GMT

Title: Interactions of bacterial polysaccharides with cationic dyes: Physicochemical studies

Authors: Dasgupta, S; Nath, R K; Biswas, S; Mitra, A; Panda, A K

Abstract: Capsular polysaccharides (SPS) are an integral component of gram-negative bacteria, and also have potential use as vaccine. In this paper, interactions of SPS isolated from Klebsiella strains K20 and K51 with cationic dyes pinacyanol chloride (PCYN) and acridine orange (AO) were studied by absorbance and fluorescence measurements. Both the polysaccharides having glucuronic acid as the potential anionic site induced strong metachromasy (blue shift ~100 nm) in the PCYN. The spectral changes were studied at different polymer/dye molar ratios (P/D = 0-40). A complete reversal of metachromasy was observed upon addition of co-solvents, suggesting the breakaway of dye molecules from the biopolymer matrix. Binding constant, changes in free energy, enthalpy and entropy of the dye polymer complex were also computed from the spectral data at different temperatures to reveal the nature of the interaction. Quenching of fluorescence of AO by the polymers and the incorporated mechanisms were also explored.

Page(s): 192-197

Characterization of water binding and germination traits of magnetically exposed maize (Zea mays L.) seeds equilibrated at different relative humidities at two temperatures

Sun, 29 Mar 2009 22:58:59 GMT

Title: Characterization of water binding and germination traits of magnetically exposed maize (Zea mays L.) seeds equilibrated at different relative humidities at two temperatures

Authors: Vashisth, Ananta; Nagarajan, Shantha

Abstract: A study was undertaken to characterize the water sorption properties and enhancement in germination and seedling vigour of maize (Zea mays L.) seeds exposed to static magnetic fields of 100 mT and 200 mT for 2 and 1h, respectively. Water sorption isotherms were constructed for magnetically- exposed and unexposed seeds by equilibrating over different saturated salt solutions at 25 and 35°C. The germination and vigour parameters were evaluated for magnetically-exposed and unexposed seeds, equilibrated over the wide range of relative humidities (RHs) at 25 and 35°C. Moisture content increased with increase in RH and decreased with increase in equilibrium temperature. The germination and vigour reduced at high and very low humidities. Magnetically-exposed seeds maintained higher germination and vigour at both temperatures and all RHs, indicating the better quality of magnetically- exposed seeds. The leachate conductivity of magnetically-exposed seeds was lower than unexposed seeds at all RHs, suggesting better membrane integrity in magnetically-exposed seeds. Analysis of the isotherms using D’Arcy-Watt equation revealed that irrespective of the temperature, in magnetically-treated seeds weak binding sites were more and strong and multi-molecular binding sites were less compared to the unexposed seeds. Total binding sites were more in unexposed control seeds. The modification of binding properties of seed water and increased seed membrane integrity in magnetically-exposed seeds might have enhanced the germination traits and early seedling growth of maize.

Page(s): 184-191

Optimization of physical parameters for lipase production from Arthrobacter sp. BGCC#490

Sun, 29 Mar 2009 22:58:59 GMT

Title: Optimization of physical parameters for lipase production from Arthrobacter sp. BGCC#490

Authors: Sharma, Anjana; Bardhan, Dipa; Patel, Rashmi

Abstract: The physical parameters for the production of thermostable, alkaline lipase from Arthrobacter sp. BGCC# 490 were optimized using response surface methodology (RSM), employing face centered central composite design (FCCCD). The design was employed by selecting pH, temperature and incubation period as the model factors and to achieve maximum yield, interaction of these factors was studied by RSM. A second-order quadratic model and response surface method showed that the optimum conditions for lipase production (pH 10.0, temperature 40^oC and incubation period 48 h) resulted in 1.6-fold increase in lipase production (13.75 EUml^-1), as compared to the initial level (8.6 EUml^-1) after 48 h of incubation, whereas its value predicted by the quadratic model was 12.8 EUml^-1. Lipase showed stability in the pH range 8-10 and temperature range 40-60^oC, with maximum activity at pH 9.0 and temperature 50^oC. Lipase activity was enhanced in the presence of K⁺, Ca²⁺ and Mg²⁺ ions, but inhibited by Hg²⁺ ions. The enzymeexhibited high activity in the presence of acetone, isopropanol and ethanol, but was unaffected by methanol. These properties suggest that the lipase may find potential applications in the detergent industry. The present work also demonstrated the feasibility of using experimental design tools to optimize physical parameters for lipase production by an indigenous Arthrobacter sp.

Page(s): 178-183