Capsaicin inhibits calmodulin-mediated oxidative burst in rat macrophages

In this study we seek to elucidate the interaction of capsaicin with the calmodulin mediated signal pathways in macrophages, by comparing its action on macrophage functions with a known calmodulin antagonist, fluphenazine. Kinetics of capsaicin uptake by macrophages (10³ cells) revealed that a maximum of 200 μM capsaicin was taken up within 10 min. Ca²⁺ ionophore triggered generation of superoxide anion and hydrogen peroxide by macrophages was inhibited in a dose-dependent manner by fluphenazine (IC₅₀, 20 μM and 12 μM, respectively) and also by capsaicin (IC₅₀, 30 μM and 9 μM, respectively), suggesting an involvement of calmodulin in the regulation of NADPH oxidase. In vitro both fluphenazine and capsaicin inhibited Ca²⁺-Mg²⁺ ATPase and cAMP-phosphodiesterase from macrophages and this inhibition was reversed by exogenous addition of calmodulin. Fluorescence studies revealed a direct Ca²⁺ dependent interaction of capsaicin with calmodulin. From these results we suggest that capsaicin acts via calmodulin to inhibit stimulus-induced macrophage oxidative burst and also that calmodulin regulates the oxidative burst in macrophages.     

Growth and biochemical characteristics of an indigenous freshwater microalga,Scenedesmus obtusus,cultivated in an airlift photobioreactor: effect of reactor hydrodynamics,light intensity,and photoperiod

Bioprocess and Biosystems Engineering - The freshwater green algae, Scenedesmus obtusus, was cultivated in a 3.4 L airlift photobioreactor. The hydrodynamic parameters were estimated at...     

Production and optimization of microbial lipase

Production of lipase by the newly isolated Pseu-domonas species has been optimised. Various parameters like initial pH, temperature, incubation period, effect of agitation, inoculum age, inoculum concentration were optimised. It was observed that modified GYP media with 72 hrs incubation, pH 5.5, at 37?°C in agitation conditions were optimum for growth and production of lipase. While optimising the effect of some additional carbon and nitrogen sources, 7% (v/v) olive oil concentration, and 1% (w/v) mannose were found to be the best. In between prediction of the activities has been done through computer programming.