Carboxylesterases from the seeds of an underutilized legume, Mucuna pruriens; Isolation, purification and characterization

Two carboxylesterases (ME-III and ME-IV) have been purified to apparent homogeneity from the seeds of Mucuna pruriens employing ammonium sulfate fractionation, cation exchange chromatography on CM-cellulose, gel-permeation chromatography on Sephadex G-100 and preparative PAGE. The homogeneity of the purified preparations was confirmed by polyacrylamide gel electrophoresis (PAGE), gel-electrofocussing and SDS-PAGE. The molecular weights determined by gel-permeation chromatography on Sephadex G-200 were 20.89 kDa (ME-III) and 31.62 kDa (ME-IV). The molecular weights determined by SDS-PAGE both in the presence and absence of 2-mercaptoethanol were 21 kDa (ME-III) and 30.2 kDa (ME-IV) respectively, suggesting a monomeric structure for both the enzymes. The enzymes were found to have Stokes radius of 2.4 nm (ME-III) and 2.7 nm (ME-IV). The isoelectric pH values of the enzymes, ME-III and ME-IV, were 6.8 and 7.4, respectively. ME-III and ME-IV were classified as carboxylesterases employing PAGE in conjunction with substrate and inhibitor specificity. The K m of ME-III and ME-IV with 1-naphthyl acetate as substrate was 0.1 and 0.166 mM while with 1-naphthyl propionate as substrate the K m was 0.052 and 0.0454 mM, respectively. As the carbon chain length of the acyl group increased, the affinity of the substrate to the enzyme increased indicating hydrophobic nature of the acyl group binding site. The enzymes exhibited an optimum temperature of 45 °C (ME-III) and 37 °C (ME-IV), an optimum pH of 7.0 (ME-III) and 7.5 (ME-IV) and both the enzymes (ME-III and ME-IV) were stable up to 120 min at 35 °C. Both the enzymes were inhibited by organophosphates (dichlorvos and phosphamidon), but resistant towards carbamates (carbaryl and eserine sulfate) and sulphydryl inhibitors (p-chloromercuricbenzoate, PCMB). © 2011 Elsevier Ltd. All rights reserved

Analyzing Inter-modal Competition between High Speed Rail and Conventional Transport Systems: A Game Theoretic Approach

AbstractA methodology is developed in order to assess the viability of transport infrastructure investment in the form of High Speed Rail (HSR). Public transportation mode operators such as HSR, conventional trains and buses, maximize their profits by varying prices and frequency for a given demand and infrastructure cost. In this study, the price competition between different operators is taken into consideration and the change in the existing market equilibrium due to the entry of the new mode is studied using the game theoretic approach. Hypothetical data for a particular route is used for game-based analysis. In this multiplayer game, the effect of introducing the new mode of transport on the Nash equilibrium is studied taking into account the competition between the other modes of transportation. The analysis of market share for the modes has been carried out using heterogeneity of the passengers based on the concept of Value-of-Time (VOT). The passengers are assumed to be intelligent and rational in choosing the mode that minimizes their generalized travel cost, which is a function of travel time weighted by the individual VOT and the monetary cost associated with the mode of travel. Thus, different combinations of entry and response strategies are studied for HSR and existing modes, and the impact of introduction of HSR is assessed in terms of profit, thus, reflecting on the sustainability and financial viability of the transport infrastructure investment

Strategies to Reduce Radiation Exposure in Electrophysiology and Interventional Cardiology

Clinical diagnosis sometimes involves the use of medical instruments that employ ionizing radiation. However, ionizing radiation exposure is a workplace hazard that goes undetected and is detrimental to patients and staff in the catheterization laboratory. Every possible effort should be made to reduce the amount of radiation, including scattered radiation. Implementing radiation dose feedback may have a role in reducing exposure. In medicine, it is important to estimate the potential biologic effects on, and the risk to, an individual. In general, implantation of cardiac resynchronization devices is associated with one of the highest operator exposure doses due to the proximity of the operator to the radiation source. All physicians should work on the principle of as low as reasonably achievable. Methods for reducing radiation exposure must be implemented in the catheterization laboratory. In this article, we review the available tools to lower the radiation exposure dose to the operator during diagnostic, interventional, and electrophysiological cardiac procedures

CHARACTERIZATION OF ALPHA-AMYLASE FROM THE SEEDS OF Mucuna pruriens

Amylases are hydrolytic enzymes which are widely distributed in nature, animals, plants and microorganisms. Amylases are of great significance in present-day biotechnology. In present study, amylases are isolated from the soaked seeds of Mucuna pruriens under extreme acidic conditions. Conventional protein purification techniques such as salt fractionation, ion exchange chromatography on CM-cellulose and sephadex G-75 was employed for the purification of amylase from the seeds of Mucuna pruriens. The amylase activity was eluted in one peak. The specific activity and yield of the purified amylase was 6.25 and 29.99, respectively. Native PAGE, SDS-PAGE and gel electrofocussing were employed to establish homogeneity of the purified amylase. SDS-PAGE and gel-filtration chromatography on sephadex G-75 was used to determine the molecular weight of the purified amylase. The purified amylase was nearly homogenous and its molecular weight was found to be 78.4 kDa. The optimum pH and temperature of the purified amylase were 7.0 and 50oC, respectively. The isolectric pH of the purified amylase was 7.2 and the activity was linear up to 60 minutes

Variations in the esterase activity during the germination period of Jatropha curcas seeds

Germination brings out the synthesis or activation of enzymes responsible for the degradation of seeds reserves. Among these enzymes, esterases are involved in the metabolic processes of germination and maturation of plants. They are constitutively expressed in seeds during germination to release the reserve materials for the growing embryo. In the present study, total protein content and esterase activity was monitored in germinating Jatropha curcas seeds. The esterase activity and specific activity observed were 9.07 µmoles/min/gm and 0.09258 IU/mg, respectively. Electophoretic analysis for esterase activity showed thirteen bands of esterases, among these 8 esterolytic bands were major and remaining were minor bands. The protein content and esterase activity decreased on 2nd, 4th, 5th and 8th day of seed germination and activity increased on 3rd, 6th, 7th day of germination. Similarly esterase activity increased on 7th day and decreased on 8, 9 and 10th day in the shoot tissue. ÂÂ

CERTAIN OBSERVATIONS ON THE DOUBLE COCOONS OF SOME PURE AND HYBRID COMBINATIONS OF BOMBYX MORI LINN.

Observations on the double cocoons in relation to sex association and orientation pattern of pupae of nine pure and hybrid combinations have been made. Double cocoon formation percentage was in between 1.79 to 6.38. Male female sex association was found more in both the pure and hybrids excepting a multivoltine race (pnd-rech) where it was only 28.57%. Orientation pattern of pupae in the same direction was in the range of 92-95%. Overall sex ratio of male and female was almost 1: 1 excepting two pure races i.e. pnd-rech (MV) and NB18 (BV) where it was in the ratio of 1: 1.8 and 1: 1.5, respectively

Oral and dermal toxicity of some insecticides to Indian honey beem Apis cerana F.

The recommended dose of alphamethrin, carbaryl, carbosulfan, chlorpyriphos, cypermethrin, diazinon, dimethioate, endosulfan, fenitrothion, fenvalerate, malathion, methylparathion, monocrotophos and quinalphos, was tested for oral and dermal toxicity against Indian honey bee, Apis cerana under lab. conditions. Both in oral and dermal toxicity tests, the mortality of honeybee increased with increase in time. The oral toxicity in descending order was as follows: carbaryl > quinalphos > carbosulfan > dimethoate > methylparathion > cypermethrin > monocrotophos > fenitrothion > fenvalerate > alphamethrin > malathion > chlorpyriphos > endosulfan > diazinon

Dry sliding wear response of A413 alloy:Influence of intermetallics and test parameters

Intermetallic particles of Al3Ti, TiB2, AlB2 and Al4Sr were added to A413 alloy, and sliding wear tests were carried out under dry sliding conditions at room temperature as well as at high temperatures of 60, 120,and180 1C. The results demonstrate that contacting surfaces at high temperature conditions are susceptible to oxidation and the wear rate of reinforced alloys is reduced. This is due to the formation of glazing layer that offers protection. Moreover,intermetallic particles played an important role as grain modifier/refiner and were responsible for reduced wear and friction