Indian journal of biochemistry & biophysics最新文献

Polypyrrole (PPy)-bile salt composite was used for sensing ethanol vapor. PPy was synthesized by interface polymerization for subsequent fabrication of thin film of its composite with bile salt, by in-situ co-dispersion method and then exposed to ethanol vapour. Sensing was visualized through changes in morphological, structural and optical characterizations. The ethanol exposed film showed larger agglomeration as revealed in its surface morphology on scanning electron microscope (SEM) and greater crystallinity as seen through X-Ray diffraction (XRD). Fourier transform infra red (FTIR) and nuclear magnetic resonance spectroscopy (NMR) of the ethanol incorporated film also gave signature of the presence of bile salt and alcohol. Alcohol incorporation pattern resulted in increase in electrical conductance from 7.08539 x 10(-5) mA/V to 8.0356 x 10(-5) mA/V, as determined from current voltage characterizations. Average molecular weight (M(n)) obtained from gel permeation chromatography changed from 6160 to 10300 on ethanol intake. Photoluminescence (PL) intensity was quenched and the PL peak shifted from 430 to 409 on ethanol exposure. Changes in morphological, structural, optical and electrical properties of the composite on ethanol exposure showed its prospective application for sensing ethanol.

Recombinases are known to play an important role in the homology search and strand exchange during meiosis as well as homologous recombination (HR)-mediated DNA repair specifically require Mg2+ ion for their activity. The Ca2+ has been shown to stimulate the strand exchange activity of hDmc1 and ScDmc1 by forming the extended filaments on DNA. Oryza sativa disrupted meiotic cDNA1A (OsDmc1A), a homologue of yeast and human Dmc1 from rice shows the hallmark functions of recombinase. Here, we report the effects of Ca2+ and Mg2+ on OsDmc1A activity from rice (Oryza sativa). OsDmc1A showed a concentration-dependent binding with both single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) substrates in presence of Mg2+ or Ca2+. The ssDNA and dsDNA binding activities, as well as renaturation activity of OsDmc1A were similar in the presence of Ca2+ or Mg2+. Increasing the Ca2+ or Mg2+ increased the DNA binding, renaturation and strand exchange of OsDmc1A. But, OsDmc1A showed only a slight stimulation of strand exchange activity in presence of Ca2+, when compared the activity in presence of Mg2+. Electron microscopy showed that OsDmc1A formed ring-like structures in presence of Mg2+ or Ca2+. However, OsDmc1A formed filament like structures with both ss and dsDNA in presence of Mg2+ or Ca2+. Taken together, Ca2+ did not affect OsDmc1A recombinase activity significantly.

A new hallmark of cancer involves acquisition of a lipogenic phenotype which promotes tumorigenesis. Little is known about lipid metabolism in melanomas. Therefore, we used BRB (Biometrics Research Branch) class comparison tool with multivariate analysis to identify differentially expressed genes in human cutaneous melanomas, compared with benign nevi and normal skin derived from the microarray dataset (GDS1375). The methods were validated by identifying known melanoma biomarkers (CITED1, FGFR2, PTPRF, LICAM, SPP1 and PHACTR1) in our results. Eighteen genes regulating metabolism of fatty acids, lipid second messengers and gangliosides were 2-9 fold upregulated in melanomas of GDS-1375. Out of the 18 genes, 13 were confirmed by KEGG pathway analysis and 10 were also significantly upregulated in human melanoma cell lines of NCI-60 Cell Miner database. Results showed that melanomas upregulated PPARGC1A transcription factor and its target genes regulating synthesis of fatty acids (SCD) and complex lipids (FABP3 and ACSL3). Melanoma also upregulated genes which prevented lipotoxicity (CPT2 and ACOT7) and regulated lipid second messengers, such as phosphatidic acid (AGPAT-4, PLD3) and inositol triphosphate (ITPKB, ITPR3). Genes for synthesis of pro-tumorigenic GM3 and GD3 gangliosides (UGCG, HEXA, ST3GAL5 and ST8SIA1) were also upregulated in melanoma. Overall, the microarray analysis of GDS-1375 dataset indicated that melanomas can become lipogenic by upregulating genes, leading to increase in fatty acid metabolism, metabolism of specific lipid second messengers, and ganglioside synthesis.

Chitinases are the hydrolytic enzymes which protect plants against pathogen attack. However, the precise role of chitinases in disease resistance has not been explored in wheat. In the present study, in silico approach, including secondary structure analysis, detailed signature pattern study, cis-acting regulatory elements survey, evolutionary trends and three-dimensional molecular modeling was used for different chitinase classes of wheat (Triticum aestivum). Homology modeling of class I, II, IV and 3 chitinase proteins was performed using the template crystal structure. The model structures were further refined by molecular mechanics methods using different tools, such as Procheck, ProSA and Verify3D. Secondary structure studies revealed greater percentage of residues forming a helix conformation with specific signature pattern, similar to casein kinase II phosphorylation site, amidation site, N-myristoylation (N-MYR) site and protein kinase C phoshorylation site. The expression profile suggested that wheat chitinase gene was highly expressed in cell culture and callus. We found that wheat chitinases showed more functional similarity with rice and barley. The results provide insight into the evolution of the chitinase family, constituting a diverse array of pathogenesis-related proteins. The study also provides insight into the possible binding sites of chitinase proteins and may further enhance our knowledge of fungal resistance mechanism in plants.

Lipases are the enzymes of choice for laundry detergent industries, owing to their triglyceride removing ability from the soiled fabric, which eventually reduces the usage of phosphate-based chemical cleansers in the detergent formulation. In this study, a novel thermo-alkaline lipase-producing strain identified as Bacillus stearothermophilus was isolated from the soil samples of olive oil mill. Enhanced lipase production was observed at 55 degrees C, pH 11 and after 48 h of incubation. Among the substrates tested, xylose (a carbon source), peptone (a nitrogen source) and olive oil at a concentration of 1% were suitable substrates for enhancing lipase production. MgSO4 and Tween-80 were suitable substrates for maximizing lipase production. The enzyme was purified to homogeneity by a single CM-Sephadex column chromatography and revealed molecular mass of 67 kDa. The enzyme (BL1) was active over a wide range of pH from 9.0 to 13.0, with an optimum at pH 11.0, exhibited maximal activity at 55 degreesC and retained more than 70% of its activity after incubation at 70 degrees C or pH 13 for 0.5 h or 24 h, respectively. The enzyme hydrolyzed both short and long-chain triacylglycerols at comparable rates. BL1 was studied in a preliminary evaluation for use in detergent formulation solutions. This novel lipase showed extreme stability towards non-ionic and anionic surfactants after pre-incubation for 1 h at 40 degrees C, and good stability towards oxidizing agents. Additionally, the enzyme showed excellent stability and compatibility with various commercial detergents, suggesting its potential as an additive in detergent formulations.

The carboxylic groups of glutamic acid and aspartic acid residues of catalase (CAT) were chemically modified using the treatment of the enzyme with 1-ethyl-3-(3'-dimethylamino) carbodiimide hydrochloride (EDC) and neomycin. The effect of covalent attachment of neomycin on the enzymatic activity, conformational and aggregation properties of CAT was investigated. The modification of CAT with different concentrations of neomycin showed two different types of behavior, depending up on the concentration range of neomycin. In the concentration range from 0.0 to 5.2 mM, neomycin-modified CAT, compared to the native enzyme exhibited higher a-helix content, reduced surface hydrophobicity, little enhancement in CAT activity and a better protection against thermal aggregation, whereas at concentrations greater than 5.2 mM, the modified enzyme exhibited a significant decrease in CAT activity and an increase in random coil content which may result in disorder in the protein structure and increase in thermal aggregation. This modification is a rapid and simple approach to investigate the role of aspartate and glutamate residues in the structure, function and folding of CAT.

The effect of homogeneous fibrin (Fb), collagen (Coll) and composite fibrin-heparin (Fb-Hp), fibrin-collagen (Fb-Coll) membranes on in vitro release of platelet-derived growth factor (PDGF-BB) was evaluated in the presence or absence of amoxicillin using of the ELISA immunoassay test. Amoxicillin concentration was determined spectrophotometrically at 272 nm. The process of the PDGF-BB growth factor and amoxicillin release from the studied membranes was of a two-phase nature in the majority of the systems analysed. The PDGF-BB was released in the highest amount from the Coll membrane (M7) without the presence of amoxicillin--546.2 ± 7.47 pg, t0.5 = 0.88 h and 202.5 ± 6.83 pg, t0.5 = 26.65 h during the first phase and second phase, respectively. The lowest PDGF-BB release was observed from composite M4 (Fb-Hp) membrane--5.88 ± 0.81 pg, t0.5 = 1.69 h; and 110.2 ± 6.48 pg, t0.5 = 855.6 h during first and second phase respectively. An optimal release of amoxicillin was observed in the case of the composite M6 (Fb-Coll) membrane--only in the second phase: 64.2 ± 7.8 μg, t0.5 = 83.5 h. The lowest and delayed amoxicillin release was achieved for M4 membrane (approx. 17.1 ± 1.12 μg, t0.5 = 46.5 h). The results of the PDGF-BB release and amoxicillin from membranes indicated a correlation between the level of release and composition of the film. Our results suggested that fibrin and collagen membranes may be beneficial to enhance periodontal bone regeneration.