AtHsp101 research sets course of action for the genetic improvement of crops against heat stress

Journal of Plant Biochemistry and Biotechnology - Caseinolytic protease (Clp)/Hsp100 proteins are members of the AAA+ (ATPase associated with a variety of cellular activities) family of proteins...     

Protein arginine methyltransferase 5 (PRMT5) activates WNT/β-catenin signalling in breast cancer cells via epigenetic silencing of DKK1 and DKK3

Protein arginine methyltransferase 5 (PRMT5) activity is dysregulated in many aggressive cancers and its enhanced levels are associated with increased tumour growth and survival. However, the role of PRMT5 in breast cancer remains underexplored. In this study, we show that PRMT5 is overexpressed in breast cancer cell lines, and that it promotes WNT/β-CATENIN proliferative signalling through epigenetic silencing of pathway antagonists, DKK1 and DKK3, leading to enhanced expression of c-MYC, CYCLIN D1 and SURVIVIN. Through chromatin immunoprecipitation (ChIP) studies, we found that PRMT5 binds to the promoter region of WNT antagonists, DKK1 and DKK3, and induces symmetric methylation of H3R8 and H4R3 histones. Our findings also show that PRMT5 inhibition using a specific small molecule inhibitor, compound 5 (CMP5), reduces PRMT5 recruitment as well as methylation of H3R8 and H4R3 histones in the promoter regions of DKK1 and DKK3, which consequently results in reduced expression CYCLIN D1 and SURVIVIN. Furthermore, CMP5 treatment either alone or in combination with 5-Azacytidine and Trichostatin A restored expression of DKK1 and DKK3 in TNBCs. PRMT5 inhibition also altered the growth characteristics of breast cancer cells and induced their death. Collectively, these results show that PRMT5 controls breast cancer cell growth through epigenetic silencing of WNT/β-CATENIN pathway antagonists, DKK1 and DKK3, resulting in up-regulation of WNT/β-CATENIN proliferative signalling.     

Mathematica numerical simulation of peristaltic biophysical transport of a fractional viscoelastic fluid through an inclined cylindrical tube

This paper studies the peristaltic transport of a viscoelastic fluid (with the fractional second-grade model) through an inclined cylindrical tube. The wall of the tube is modelled as a sinusoidal wave. The flow analysis is presented under the assumptions of long wave length and low Reynolds number. Caputo's definition of fractional derivative is used to formulate the fractional differentiation. Analytical solutions are developed for the normalized momentum equations. Expressions are also derived for the pressure, frictional force, and the relationship between the flow rate and pressure gradient. Mathematica numerical computations are then performed. The results are plotted and analysed for different values of fractional parameter, material constant, inclination angle, Reynolds number, Froude number and peristaltic wave amplitude. It is found that fractional parameter and Froude number resist the flow pattern while material constant, Reynolds number, inclination of angle and amplitude aid the peristaltic flow. Furthermore, frictional force and pressure demonstrate the opposite behaviour under the influence of the relevant parameters emerging in the equations of motion. The study has applications in uretral biophysics, and also potential use in peristaltic pumping of petroleum viscoelastic bio-surfactants in chemical engineering and astronautical applications involving conveyance of non-Newtonian fluids (e.g. lubricants) against gravity and in conduits with deformable walls.     

Synthesis of azatricyclodiones & octahydro-benzo[f]isoindoles and their antimicrobial evaluation

A series of azatricyclodiones and octahydro-benzo[f]isoindoles have been synthesized by (4+2) Diels-Alder cycloaddition of maleimides with furfuryl amine. Reaction of azatricyclodiones with isocyanates led to the respective ureides. All of the compounds were screened against a number of bacteria and fungi. One of the compounds (2) displayed moderate antitubercular activity while two compounds (2) and (4) inhibited the fungal growth at 25 μg/mL.     

Synthesis and biological evaluation of potential modulators of malarial glutathione-S-transferase(s)

Glutathione-S-transferase(s) (E.C.2.5.1.18, GSTs) have been investigated in parasitic protozoans with respect to their biochemistry and they have been identified as potential vaccine candidates in protozoan parasites and as a target in the synthesis of new antiparasitic agents. In a search towards the identification of novel biochemical targets for antimalarial drug design, the area of Plasmodium glutathione metabolism provides a number of promising chemotherapeutic targets. GST activity was determined in various subcellular fractions of malarial parasites Plasmodium yoelii and was found to be localized mainly in the cytosolic fraction (specific activity, c. 0.058 ± 0.016 μmol/min/mg protein). Hemin, a known inhibitor of mammalian GST(s), maximally inhibited this enzyme from P. yoelii to nearly 86%. In a search towards synthetic modulators of malarial GST(s), 575 compounds belonging to various chemical classes were screened for their effect on crude GST from P. yoelii and 92 compounds belonging to various chemical classes were studied on recombinant GST from P. falciparum. Among all the compounds screened, 83 compounds inhibited/stimulated the enzyme from P. yoelii/P. falciparum to the extent of 40% or more.     

Synthesis and Hybridization Studies of Oligonucleotide Sequences with Modified Fluorescent Nucleoside Analogs

Abstract

Two complementary oligodeoxynucleotide hexamers CATGAA and TTCATG and a pentamer with a fluorescent nucleoside analog viz. 9-N-(2′-deoxy-β-D-ribofuranosyl) carbazole (C*) incorporated into it, TTC*ATG were synthesized and characterised by spectroscopic and chromatographic studies. The comparative fluorescent studies of the two nucleoside analogs viz. 9-N-(2′-deoxy-β-D-ribofuranosyl) acridone and its carbazole analog (C*) have been carried out under different experimental conditions. The effect on fluorescence by incorporation of (C*) into the sequence and its subsequent hybridization with the complementary sequence have been studied.     

Purification and characterization of an extracellular antifungal chitinase from Penicillium ochrochloron MTCC 517 and its application in protoplast formation

A highly chitinolytic strain Penicillium ochrochloron MTCC 517 was procured from MTCC, Chandigarh, India. Culture medium supplemented with 1% chitin was found to be suitable for maximum production of chitinase. Purification of extracellular chitinase was done from the culture medium by organic solvent precipitation and DEAE-cellulose column chromatography. The chitinase was purified 6.92-fold with 29.9% yield. Molecular mass of purified chitinase was found to be 64 kDa by SDS-PAGE. The chitinase showed optimum temperature 40 °C and pH 7.0. The enzyme activity was completely inhibited by Hg²⁺, Zn²⁺, K⁺ and NH₄⁺. The enzyme kinetic study of purified chitinase revealed the following characteristics, such as apparent K_m 1.3 mg ml^?1, V_max 5.523 × 10^?5 moles l^?1 min^?1 and K_cat 2.37 s^?1 and catalytic efficiency 1.82 s^?1 M^?1. The enzyme hydrolyzed colloidal chitin, glycol chitin, chitosan, glycol chitosan, N,N′-diacetylchitobiose, p-nitrophenyl N-acetyl-β-d-glucosaminide and 4-methylumbelliferyl N-acetyl-β-d-glucosaminide. The chitinase of P. ochrochloron MTCC 517 is an exoenzyme, which gives N-acetylglucosamine as the main hydrolyzate after hydrolysis of colloidal chitin. Protoplasts with high regeneration capacity were obtained from Aspergillus niger using chitinase from P. ochrochloron MTCC 517. Since it also showed antifungal activity, P. ochrochloron MTCC 517 seems to be a promising biocontrol agent.     

Potential Application of Turnip Oil (Raphanus sativus L.) for Biodiesel Production: Physical–Chemical Properties of Neat Oil, Biofuels and their Blends with Ultra-Low Sulphur Diesel (ULSD)

Turnip oil (TO; Raphanus sativus L.) produces seeds that contain around 26 wt% of inedible base stock that are suitable as a potential feedstock for biodiesel production. A turnip oil methyl ester (TME) was prepared from acid-catalyzed pretreated TO in an effort to evaluate important fuel properties of turnip oil-based biodiesel, such as kinematic viscosity, cloud point, pour point (PP), cold filter plugging point, acid value, oxidative stability and lubricity. A comparison was made with soybean oil methyl esters (SME) as per biodiesel fuel standards such as ASTM D6751 and EN 14214. TME was characterized using FTIR, HPLC and ¹H NMR. Except PP property, SME displays superior fuel properties compared to TME. Blends (B5 and B20) of TME in ultra-low sulphur diesel fuel (ULSD) were also assessed for the aforesaid fuel properties and compared to an analogous set of blends of soybean oil methyl ester in ULSD as per petro diesel fuel standards such as ASTM D975 and D7467. TME B5 blends in ULSD displayed improved PP property in comparison to neat ULSD and blends of SME in ULSD. It was demonstrated that the B5 and B20 blends of TME in ULSD had acceptable fuel properties as per ASTM D975 (for B5 blend) and ASTM D7467 (for B20 blend). In summary, turnip oil has potential as an alternative, non-food feedstock for biodiesel production.     

Plasmon-Enhanced Light Trapping to Improve Efficiency of TiO2 Nanorod-Based Dye-Sensitized Solar Cell

Localized surface plasmon resonance incurred by silver nanoparticles is used to enhance the photoelectric conversion efficiency of a TiO₂ nanorod-based dye-sensitized solar cell (DSSC). Improved light transmission is observed experimentally in silver nanoparticle-coated FTO glass. The transmission data are used to explore the effect on electrical parameters of DSSC using theoretical model. Current density increased from 11.7 to 12.34 mA/cm² and open-circuit voltage increased from 704 to 709.5 mV. Overall efficiency enhancement of 6.67 % is observed in TiO₂ nanorod-based DSSC due to plasmon-induced light trapping.