Bharati A.,Institute of Life science
Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo), behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the Q(B); the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth. Source
Veiga-Parga T.,University of Tennessee at Knoxville |
Sehrawat S.,Institute of Life science |
Rouse B.T.,University of Tennessee at Knoxville
The host response to viruses includes multiple cell types that have regulatory function. Most information focuses on CD4+ regulatory T cells that express the transcription factor Foxp3+ (Tregs), which are the topic of this review. We explain how viruses through specific and non-specific means can trigger the response of thymus-derived natural Tregs as well as induce Tregs. The latter derive under appropriate stimulation conditions either from uncommitted precursors or from differentiated cells that convert to become Tregs. We describe instances where Tregs appear to limit the efficacy of antiviral protective immunity and other, perhaps more common, immune-mediated inflammatory conditions, where the Tregs function to limit the extent of tissue damage that occurs during a virus infection. We discuss the controversial roles that Tregs may play in the pathogenesis of human immunodeficiency and hepatitis C virus infections. The issue of plasticity is discussed, as this may result in Tregs losing their protective function when present in inflammatory environments. Finally, we mention approaches used to manipulate Treg numbers and function and assess their current value and likely future success to manage the outcome of virus infection, especially those that are responsible for chronic tissue damage. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source
Institute Of Life Science | Date: 2011-11-11
A novel method of isolation of TLR4 from cell lysates of mononuclear cells is provided. The method includes: collecting bovine adult filarial parasites (
Institute Of Life Science | Date: 2013-03-15
The present invention is an aqueous dispersible magnetic nanoparticle formulation with a high drug loading capacity used for sustained drug delivery. The formulated magnetic nanoparticles are composed of an iron oxide core coated with a long chain polymer, which provides aqueous dispersibility without the use of surfactant. A method is developed for the functionalization of magnetic nanoparticles for use in biomedical field.
Institute Of Life Science | Date: 2010-12-15
A process for preparing curcumin encapsulated chitosan alginate sponge comprising the steps of: incorporating curcumin in a fluid phase of oleic acid; subjecting the mixture to a step of emulsification with chitosan solution by homogenization; emulsifying the resultant solution with alginate solution by homogenization; lyophilizing the final emulsion by freeze drying to produce curcumin loaded AC sponge.