Mechanisms of curcumin-induced apoptosis of Ehrlich's ascites carcinoma cells.

Curcumin, the active ingredient from the spice turmeric (Curcuma longa Linn), is a potent antioxidant and anti-inflammatory agent. It has been recently demonstrated to possess discrete chemopreventive activities. However, the molecular mechanisms underlying such anticancer properties of curcumin still remain unrealized, although it has been postulated that induction of apoptosis in cancer cells might be a probable explanation. In the current study, curcumin was found to decrease the Ehrlich's ascites carcinoma (EAC) cell number by the induction of apoptosis in the tumor cells as evident from flow-cytometric analysis of cell cycle phase distribution of nuclear DNA and oligonucleosomal fragmentation. Probing further into the molecular signals leading to apoptosis of EAC cells, we observed that curcumin is causing tumor cell death by the up-regulation of the proto-oncoprotein Bax, release of cytochrome c from the mitochondria, and activation of caspase-3. The status of Bcl-2 remains unchanged in EAC, which would signify that curcumin is bypassing the Bcl-2 checkpoint and overriding its protective effect on apoptosis.     

Polyaniline-carbon nanotube composite film for cholesterol biosensor

Nanocomposite film composed of polyaniline (PANI) and multiwalled carbon nanotubes (MWCNT), prepared electrophoretically onto indium tin oxide (ITO)-coated glass plate, was used for covalent immobilization of cholesterol oxidase (ChOx) via N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemistry. Results of linear sweep voltammetric measurements reveal that ChOx/PANI-MWCNT/ITO bioelectrode can detect cholesterol in the range of 1.29 to 12.93 mM with high sensitivity of 6800 nA mM⁻¹ and a fast response time of 10 s. Photometric studies for ChOx/PANI-MWCNT/ITO bioelectrode indicate that it is thermally stable up to 45 °C and has a shelf life of approximately 12 weeks when stored at 4 °C. The results of these studies have implications for the application of this interesting matrix (PANI-MWCNT) toward the development of other biosensors.     

HIV-1 Gag extension: conformational changes require simultaneous interaction with membrane and nucleic acid

The retroviral Gag polyprotein mediates viral assembly. The Gag protein has been shown to interact with other Gag proteins, with the viral RNA, and with the cell membrane during the assembly process. Intrinsically disordered regions linking ordered domains make characterization of the protein structure difficult. Through small-angle scattering and molecular modeling, we have previously shown that monomeric human immunodeficiency virus type 1 (HIV-1) Gag protein in solution adopts compact conformations. However, cryo-electron microscopic analysis of immature virions shows that in these particles, HIV-1 Gag protein molecules are rod shaped. These differing results imply that large changes in Gag conformation are possible and may be required for viral formation. By recapitulating key interactions in the assembly process and characterizing the Gag protein using neutron scattering, we have identified interactions capable of reversibly extending the Gag protein. In addition, we demonstrate advanced applications of neutron reflectivity in resolving Gag conformations on a membrane. Several kinds of evidence show that basic residues found on the distal N- and C-terminal domains enable both ends of Gag to bind to either membranes or nucleic acid. These results, together with other published observations, suggest that simultaneous interactions of an HIV-1 Gag molecule with all three components (protein, nucleic acid, and membrane) are required for full extension of the protein.     

Molecular breeding: marker-assisted selection combined with biolistic transformation for blast and bacterial blight resistance in Indica rice (cv. CO39)

Based on blast pathogen population dynamics and lineage exclusion assays, we found that the major blast resistance genes Pi-1 and Piz-5 confer resistance against most Magnaporthe grisea lineages. Near-isogenic rice lines C101LAC and C101A51 carrying these two major genes for blast resistance in the background of a most blast-susceptible genotype were used for developing the pyramids. The closely linked RFLP marker RZ536 and NBS-LRR r10 marker for Pi-1 and a PCR-based SAP marker RG64 for Piz-5 were used to identify the genes in the parents and in marker-assisted breeding of the pyramided populations. To achieve multiple resistance against blast and blight in this cultivar, these blast-resistant pyramids were transformed with the cloned bacterial blight resistance gene Xa21 known to confer resistance to all races of Xanthomonas oryzae pv. oryzae (Xoo). Bioassays with six independent transformants showed that transgenic CO39 plants were resistant to both pathogens, M. grisea and Xoo. We report here the stacking of three major genes (Pi-1 + Piz-5 + Xa21) into rice using two different approaches of molecular breeding: marker-assisted selection (MAS) and genetic transformation.     

Rice caryopsis structure in relation to distribution of micronutrients (iron, zinc, β-carotene) of rice cultivars including transgenic indica rice

The transgenic indica rice lines of IR68144 and BR29, developed using endosperm-specific promoters were analyzed for their iron, zinc and β-carotene content in the endosperm. Biochemical analysis clearly revealed the presence of higher accumulation of iron, zinc and β-carotene in transgenic rice grains in comparison with control. Prussian blue staining reaction evidenced the presence of iron in the endosperm cells of transgenic rice grains in comparison with control where iron is restricted only to aleurone and embryo. The rice grain structure of IR64, IR72, IR68144, Swarna, BRRI Dhan 29 (BR29), BR28, Taipai 309 (T309) and New Plant Type-3 (NPT3) indicated that the number of aleurone layers, size of the embryo and size of the caryopsis determines the quantity of important micronutrients (iron, zinc) in the grains. Biochemical analysis revealed that iron and zinc content drastically varies in polished and unpolished rice and among the varieties examined. During the polishing process almost entire aleurone and most part of the embryo is removed which are the main storehouse for major micronutrients. It is estimated that more than 70% of micronutrients are lost during polishing process.     

Disentangling the Association between Statins,Cholesterol, and Colorectal Cancer: A Nested Case-Control Study

BackgroundSeveral prior studies have found an association between statin use and reduced risk of colorectal cancer. We hypothesized that these findings may be due to systematic bias and examined the independent association of colorectal cancer risk with statin use, serum cholesterol, and change in cholesterol concentration.ConclusionsAlthough the risk of colorectal cancer was lower in statin users versus nonusers, no difference was observed among those who continued versus discontinued statin therapy, suggesting the potential for indication bias. The association between decreased serum cholesterol and colorectal cancer risk suggests a cholesterol-lowering effect of undiagnosed malignancy. Clinical judgment should be used when considering causes of cholesterol reduction in patients, including those on statin therapy.