Structural-functional analyses of textile dye degrading azoreductase, laccase and peroxidase: a comparative in silico study

Background: Textile industry not only plays a vital role in our daily life but also a prominent factor in improving global economy. One of the environmental concern is it releases huge quantities of toxic dyes in the water leading to severe environmental pollution. Bacterial laccase and azoreductase successfully oxidize complex chemical structure of nitrogen group-containing azo dyes. Additionally, the presence of textile dye infuriates bacterial peroxidase to act as a dye degrading enzyme. Our present study deals with three textile dye degrading enzymes laccase, azoreductase, and peroxidase through analyzing their structural and functional properties using standard computational tools. Result: According to the comparative analysis of physicochemical characteristics, it was clear that laccase was mostly made up of basic amino acids whereas azoreductase and peroxidase both comprised of acidic amino acids. Higher aliphatic index ascertained the thermostability of all these three enzymes. Negative GRAVY value of the enzymes confirmed better water interaction of the enzymes. Instability index depicted that compared to laccase and preoxidase, azoreductase was more stable in nature. It was also observed that the three model proteins had more than 90% of total amino acids in the favored region of Ramachandran plot. Functional analysis revealed laccase as multicopper oxidase type enzyme and azoreductase as FMN dependent enzyme, while peroxidase consisted of α-ß barrel with additional haem group. Conclusion: Present study aims to provide knowledge on industrial dye degrading enzymes, choosing the suitable enzyme for industrial set up and to help in understanding the experimental laboratory requirements as well.

Evaluation of dermal collagen stained with picrosirius red and examined under polarized light microscopy

Abstract: The special picrosirius red staining highlights the natural birefringence of collagen fibers when exposed to polarized light. The results from birefringence allow to evaluate the organization of the collagen fibers in the tissues. The authors intend to elucidate all steps to obtain and capture images of histological sections stained with picrosirius red and evaluated under polarized light microscopy, as well as possible artefacts that may occur.

Panus tigrinus as a potential biomass source for Reactive Blue decolorization: isotherm and kinetic study

Background: Textile and dye industries pose a serious threat to the environment. Conventional methods used for dye treatment are generally not always effective and environmentally friendly. This drove attention of scores of researchers to investigate alternative methods for the biodegradation of dyes using fungal strains. In this work, white-rot fungus (Panus tigrinus) was used as a biosorbent for the decolorization of Reactive Blue 19. The process parameters that were varied were initial concentration (50­150 mg/L), contact time (30­90 min), and pH (2­6). In addition, to gain important data for the evaluation of a sorption process, the equilibrium and kinetics of the process were determined. Results: White-rot fungus showed great potential in decolorizing Azo dyes. The strain showed the maximum decolorization of 83.18% at pH 2, a contact time of 90 min, and an initial concentration of 50 mg/L. The Langmuir isotherm described the uptake of the Reactive Blue 19 dye better than the Freundlich isotherm. Analysis of the kinetic data showed that the dye uptake process followed the pseudo second-order rate expression. Conclusion: The biosorption process provided vital information on the process parameters required to obtain the optimum level of dye removal. The isotherm study indicated the homogeneous distribution of active sites on the biomass surface, and the kinetic study suggested that chemisorption is the rate-limiting step that controlled the biosorption process. According to the obtained results, P. tigrinus biomass can be used effectively to decolorize textile dyes and tackle the pollution problems in the environment.

In the final analysis, are we a consumer society or not? Implications for health / Afinal, somos ou não somos uma sociedade de consumo? Consequências para a saúde

In this paper, the question of Brazil's insertion today as a country with the characteristics of modern consumer societies is discussed, focusing on the commercialization of the health sector, the segmentation of the health system and the contradictions of the rights to health care in the social context in question. Some research data on these issues broadcast in the National News Bulletins of Globo TV during the year of 2012 are presented, in which the high technology private hospital as a consumer icon, the underfunding of the public health system and the rejection of a poor and deprived Unified Health System are analyzed.

Discute-se aqui a nossa inserção como país, hoje, nas sociedades de consumo características da modernidade, enfocando a mercantilização na área da saúde, a segmentação do sistema de saúde e as contradições do direito à saúde no contexto social em questão. São apresentados dados de pesquisa sobre o tema no Jornal Nacional da Rede Globo de Televisão, durante o ano de 2012, na qual se analisa o hospital privado de alto padrão tecnológico como ícone de consumo, o subfinanciamento do sistema público de saúde e a rejeição de um Sistema Único de Saúde pobre e carente.

Biosorption kinetics of a direct azo dye Sirius Blue K-CFN by Trametes versicolor

In this study, lyophilized Trametes versicolor biomass is used as a sorbent for biosorption of a textile dye, Sirius Blue K-CFN, from an aqueous solution. The batch sorption was studied with respect to dye concentration, adsorbent dose and equilibrium time. The effect of pH and temperature on dye uptake was also investigated and kinetic parameters were determined. Optimal initial pH (3.0), equilibrium time (2 hrs), initial dye concentration ( 100 mg l-1) and biomass concentration (1.2 mg l-1) were determined at 26ºC. The maximum biosorption capacity (q max) of Sirius Blue K-CFN dye on lyophilized T. versicolor biomass is 62.62 mg/g. The kinetic and isotherm studies indicated that the biosorption process obeys to a pseudo-second order model and Langmuir isotherm model. In addition, the biosorption capacities of fungal biomass compared to other well known adsorbents such as activated carbon and Amberlite, fungal biomass biosorptions capacities were found to be more efficient.

Efficiency evaluation of Nay zeolite and Tio[2]/NaY zeolite in removal of methylene blue dye from aqueous solutions

In this study titanium dioxide cluster was incorporated onto NaY zeolite and characterized with X-Ray diffractometer and X-ray spectroscopy. These composites have many advantages such as high stability and high porosity. The adsorption behavior of methylene blue was investigated for NaY zeolite and TiO[2]/NaY zeolite. The efficiency of time, pH, temperature and initial concentration of methylene blue [MB] on removal effect of methylene blue was investigated by UV-Vis spectroscopy. And, the optimum conditions were determined 8h time, basic pH and high initial concentrations of methylene blue and absorbent. With increasing of temperature, the removal efficiency of NaY zeolite and TiO[2]/NaY increased. Results showed that 92% and 85% of methylene blue was absorbed by synthesized NaY zeolite and TiO[2]/zeolite, respectively. Adsorption isotherm as studied by fitting data to Langmuir and Freundlich isotherms models, showed monolayer adsorption and Langmuir equilibrium model to be more relevant

Discovery of a small-molecule inhibitor for kidney ADP-ribosyl cyclase: Implication for intracellular calcium signal mediated by cyclic ADP-ribose

ADP-ribosyl cyclase (ADPR-cyclase) produces a Ca2+-mobilizing second messenger, cyclic ADP- ribose (cADPR), from beta-NAD+. A prototype of mammalian ADPR-cyclases is a lymphocyte antigen CD38. Accumulating evidence indicates that ADPR-cyclases other than CD38 are expressed in various cells and organs. In this study, we discovered a small molecule inhibitor of kidney ADPR-cyclase. This compound inhibited kidney ADPR-cyclase activity but not CD38, spleen, heart or brain ADPR-cyclase activity in vitro. Characterization of the compound in a cell-based system revealed that an extracellular calcium-sensing receptor (CaSR)- mediated cADPR production and a later long-lasting increase in intracellular Ca2+ concentration ([Ca2+]i) in mouse mesangial cells were inhibited by the pre-treatment with this compound. In contrast, the compound did not block CD3/TCR-induced cADPR production and the increase of [Ca2+]i in Jurkat T cells, which express CD38 exclusively. The long-lasting Ca2+ signal generated by both receptors was inhibited by pre-treatment with an antagonistic cADPR derivative, 8-Br-cADPR, indicating that the Ca2+ signal is mediated by the ADPR-cyclse metabolite, cADPR. Moreover, among structurally similar compounds tested, the compound inhibited most potently the cADPR production and Ca2+ signal induced by CaSR. These findings provide evidence for existence of a distinct ADPR-cyclase in the kidney and basis for the development of tissue specific inhibitors.

Biodegradation of benzidine based azodyes Direct red and Direct blue by the immobilized cells of Pseudomonas fluorescens D41.

Benzidine based azodyes are proven carcinogens, mutagens and have been linked to bladder cancer of human beings and laboratory animals. The textile and dyestuff manufacturing industry are the two major sources that released azodyes in their effluents. The dye, Direct blue contains two carcinogenic compounds namely benzidine (BZ), 4-amino biphenyl (4-ABP), while the dye Direct red has benzidine (BZ). Among 40 isolates of Pseudomonas fluorescens screened, one isolate designated as D41 was found to be capable of extensively degrading the dyes Direct blue and Direct red. Immobilized cells of P. fluorescens D41 efficiently degraded Direct red (82%) and Direct blue (71%) in the presence of glucose.

Supramolecular effects in dentritic systems containing photoactive groups

In this article are described dendritic structures containing photoactive groups at the surface or in the core. The observed supramolecular effects can be attributed to the nature of the photoactive group and their location in the dendritic architecture. The peripheric azobenzene groups in these dendrimeric compounds can be regarded as single residues that retain the spectroscopic and photochemical properties of free azobenzene moiety. The E and Z forms of higher generation dendrimer, functionalized with azobenzene groups, show different host ability towards eosin dye, suggesting the possibility of using such dendrimer in photocontrolled host-guest systems. The photophysical properties of many dendritic-bipyridine ruthenium complexes have been investigated. Particularly in aerated medium more intense emission and a longer excited-state lifetime are observed as compared to the parent unsubstituted bipyridine ruthenium complexes. These differences can be attributed to a shielding effect towards dioxygen quenching originated by the dendritic branches

Anti-implantation effect of a bone-marrow cytokine-BIM.

Successful implantation of blastocyst is dependent upon a cytokine induced localized immunosuppression at uterus. BIM, a bone marrow secreted bio-immunomodulator (BIM) has been observed to have positive immunomodulatory activity in immunosuppressed cases. As pregnancy is associated with immunosuppression upregulation of the suppressed immune system by injection of BIM (conc. 0.08 microg/g b.wt once in rats b.wt. <150 gm or 0.2 microg/g b.wt thrice in rats weighing > 160 gm) is believed to prevent implantation. The anti-implantation action of BIM is probably mediated via mononuclear cells at site of uterus, the effect is reversible and a single dose did not affect the estrous cycle. Multiple dose of BIM however, produce prolonged diestrous and this is probably an autonomic phenomena.

Spectrophotometric studies of Al [III] complexes with 4- [arylazo] -1-hydroxy-2-naphtoic acid dyes

The optimum conditions favoring the formation of Al [III] complexes with 4-arylazo-1-hydroxy-2-naphthoic acid dyes [Ia-h] are extensively investigated. The molecular structure of the complexes and their obedience to Beer's law and Ringbom ranges, as well as, their stabilities are studied. Methods for the spectrophotometric determination of Al [III] and spectrophotometric titration using EDTA and CDTA were reported. The interference effect of several ions was checked. The stoichiometry of Al [III] with [Ia-h] dyes was investigated by conductometric titrations. The study was extended to the determination of Al in pure Al metal and in Si-Al master alloy. A new rapid and accurate method for the spectrophotometric microdetermination of Al [III] using 4-[arylazo]-1-hydroxy-2-naphthoic acid dyes [Ia-h] is given

Dimerization constants of some azo dyes from proton magnetic resonance spectra-II

The effect of aggregation upon proton magnetic resonance [PMR] spectra of GI acid Red 26 and CI acid Red 27 was observed in a series of aqueous solutions of different concentrations. An upfield shift by increasing the dye concentration has been attributed to the magnetic anisotropy of ring currents in neighboring molecules. The low-field shift which accompanies the disaggregation showed the vertical array stacking of the dye anions in the micelles at high concentrations. The dimerization constant Kd and limiting chemical shifts sigma M, sigma D are calculated and discussed. Addition of salt solution and decrease in temperature favor aggregation were taken place

Studies on the dissociation constants of some substituted coumarin azo dyes in mixed solvents

In order to shed light on the effect of different mixed solvents and temperatures on the dissociation of hydroxy coumarins, the pka values of a number of substituted 8-[arylazo]-7-hydroxy-4-methylcoumarins were determined pH-metrically in the presence of some water miscible organic solvents. The effect of solvent polarity on pka values was discussed. Increase in the concentration of organic solvent from 50 to 80% by volume results in the increase of pka for all azo coumarins was detected. The thermodynamic parameters, delta Go, delta Ho and delta So were also evaluated

Spectrophotometric and potentiometric studies of some lanthanide chelates with O-chloro-Schaffer acid azo-dye

The complication of O-chloro-schaffer acid azo-dye with some lanthanides; namely, La, Pr, Nd, Sm, Eu, Gd, Er, Yb, and Lu, were studied. Lanthanides formed chelated complexes of different lambda max with orthochloro-schaffer acid azo-dye at different pH values. The composition [MR, MR2 and MR3] of the chelates investigated was established spectrophotometrically by the continuous variation of molar ratio, slope ratio, and straight line methods and by the conductometric titration method. For photometric determination of lanthanides with this reagent Sandell's sensitivity, Beer's Law were also determined. The Bjerrum and Calvin potentiometric titration technique was employed to determine the stepwise formation constants