Co-metabolic degradation of diazo dye- reactive blue 160 by enriched mixed cultures BDN

Mixed cultures BDN (BDN) proficient in decolourizing diazo dye-reactive blue 160 (RB160) consist of eight bacterial strains, was developed through culture enrichment method from soil samples contaminated with anthropogenic activities. The synthrophic interactions of BDN have led to complete decolourization and degradation of RB160 (100mg/L) within 4h along with co-metabolism of yeast extract (0.5%) in minimal medium. BDN microaerophilicaly decolourized even 1500mg/L of RB160 under high saline conditions (20g/L NaCl) at 37°C and pH 7.0. BDN exhibited broad substrate specificity and decolourized 27 structurally different dyes. The reductase enzymes symmetrically cleaved RB160 and oxidative enzymes further metabolised the degraded products and five different intermediates were identified using FTIR, (1)HNMR and GC-MS. The phytotoxicity assay confirmed that intact RB160 was more toxic than dye degraded intermediates. The BDN was able to colonize and decolourized RB160 in soil model system in presence of indigenous miocroflora as well as in sterile soil without any amendment of additional nutrients, which signifies it useful and potential application in bioremediation.

A new polymer-based laccase for decolorization of AO7: long-term storage and mediator reuse

To address the bottlenecks of laccase-based catalysis, i.e., poor long-term stability and potential secondary pollution caused by synthetic mediator, we fabricated a new biocatalyst (N-PS-Lac) through adsorption of laccase onto polystyrene anion exchangers (N-PS) binding quaternary ammonium groups. After 2-year storage, the residual activity of N-PS-Lac remained as high as 101.7%, while that for native laccase was only 14.6%. Also, N-PS-Lac exhibited improved durability against pH variation and thermal treatment at 60°C. Gaussian curve fitting of FT-IR spectra indicated that laccase conformation of N-PS-Lac was rigidified, possibly because of the host geometric restriction and the host-laccase electrostatic attraction. A two-step method, i.e., adsorption of an azo dye AO7 by N-PS and then ectopic degradation by the immobilized laccase, was proposed to reuse the mediator HOBT for seven cyclic runs, where N-PS-Lac kept the constant decolorization efficiency. AO7 solution was detoxified completely after decolorization by the two-step method.

Visualization of microbiological processes underlying stress relaxation in Pseudomonas aeruginosa biofilms

Bacterial biofilms relieve themselves from external stresses through internal rearrangement, as mathematically modeled in many studies, but never microscopically visualized for their underlying microbiological processes. The aim of this study was to visualize rearrangement processes occurring in mechanically deformed biofilms using confocal-laser-scanning-microscopy after SYTO9 (green-fluorescent) and calcofluor-white (blue-fluorescent) staining to visualize bacteria and extracellular-polymeric matrix substances, respectively. We apply 20% uniaxial deformation to Pseudomonas aeruginosa biofilms and fix deformed biofilms prior to staining, after allowing different time-periods for relaxation. Two isogenic P. aeruginosa strains with different abilities to produce extracellular polymeric substances (EPS) were used. By confocal-laser-scanning-microscopy all biofilms showed intensity distributions for fluorescence from which rearrangement of EPS and bacteria in deformed biofilms were derived. For the P. aeruginosa strain producing EPS, bacteria could not find new, stable positions within 100 s after deformation, while EPS moved toward deeper layers within 20 s. Bacterial rearrangement was not seen in P. aeruginosa biofilms deficient in production of EPS. Thus, EPS is required to stimulate bacterial rearrangement in mechanically deformed biofilms within the time-scale of our experiments, and the mere presence of water is insufficient to induce bacterial movement, likely due to its looser association with the bacteria.

Decolourisation of Acid Orange 7 recalcitrant auto-oxidation coloured by-products using an acclimatised mixed bacterial culture

This study focuses on the biodegradation of recalcitrant, coloured compounds resulting from auto-oxidation of Acid Orange 7 (AO7) in a sequential facultative anaerobic-aerobic treatment system. A novel mixed bacterial culture, BAC-ZS, consisting of Brevibacillus panacihumi strain ZB1, Lysinibacillus fusiformis strain ZB2, and Enterococcus faecalis strain ZL bacteria were isolated from environmental samples. The acclimatisation of the mixed culture was carried out in an AO7 decolourised solution. The acclimatised mixed culture showed 98 % decolourisation within 2 h of facultative anaerobic treatment using yeast extract and glucose as co-substrate. Subsequent aerobic post treatment caused auto-oxidation reaction forming dark coloured compounds that reduced the percentage decolourisation to 73 %. Interestingly, further agitations of the mixed culture in the solution over a period of 48 h significantly decolourise the coloured compounds and increased the decolourisation percentage to 90 %. Analyses of the degradation compounds using UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC) showed complete degradation of recalcitrant AO7 by the novel BAC-ZS. Phytotoxicity tests using Cucumis sativus confirmed the dye solution after post aerobic treatment were less toxic compared to the parent dye. The quantitative real-time PCR revealed that E. faecalis strain ZL was the dominant strain in the acclimatised mix culture.

Hemin-block copolymer micelle as an artificial peroxidase and its applications in chromogenic detection and biocatalysis

Following an inspiration from the fine structure of natural peroxidases, such as horseradish peroxidase (HRP), an artificial peroxidase was constructed through the self-assembly of diblock copolymers and hemin, which formed a functional micelle with peroxidase-like activity. The pyridine moiety in block copolymer poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP) can coordinate with hemin, and thus hemin is present in a five-coordinate complex with an open site for binding substrates, which mimics the microenvironment of heme in natural peroxidases. The amphiphilic core-shell structure of the micelle and the coordination interaction of the polymer to the hemin inhibit the formation of hemin μ-oxo dimers, and thereby enhance the stability of hemin in the water phase. Hemin-micelles exhibited excellent catalytic performance in the oxidation of phenolic and azo compounds by H2O2. In comparison with natural peroxidases, hemin-micelles have higher catalytic activity and better stability over wide temperature and pH ranges. Hemin-micelles can be used as a detection system for H2O2 with chromogenic substrates, and they anticipate the possibility of constructing new biocatalysts tailored to specific functions.

Process parameters for decolorization and biodegradation of orange II (Acid Orange 7) in dye-simulated minimal salt medium and subsequent textile effluent treatment by Bacillus cereus (MTCC 9777) RMLAU1

In this study, Bacillus cereus isolate from tannery effluent was employed for orange II dye decolorization in simulated minimal salt broth and textile effluent. Most of the physicochemical parameters of textile effluent were above the permissible limits. The strain was highly tolerant to dye up to 500 mg l(-1). Increasing dye concentration exerted inhibitory effect on the bacterial growth and decolorization. The maximum decolorization of initial 100 mg dye l(-1) was achieved at optimum pH 8.0 and 33 °C under static culture conditions during 96-h incubation. Supplementation with optimized glucose (0.4%, w/v) and ammonium sulfate (0.1%, w/v) with 3.0% B. cereus inoculum further enhanced dye decolorization to highest 68.5% within 96-h incubation. A direct correlation was evident between bacterial growth and dye decolorization. Under above optimized conditions, 24.3% decolorization of unsterilized real textile effluent by native microflora was achieved. The effluent decolorization enhanced substantially to 37.1% with B. cereus augmentation and to 40.5% when supplemented with glucose and ammonium sulfate without augmentation. The maximum decolorization of 52.5% occurred when textile effluent was supplemented with optimized exogenous carbon and nitrogen sources along with B. cereus augmentation. Gas chromatography-mass spectrometry identified sulfanilic acid as orange II degradation product. Fourier transform infra red spectroscopy of metabolic products indicated the presence of amino and hydroxyl functional groups. This strain may be suitably employed for in situ decolorization of textile industrial effluent under broad environmental conditions.

Radial transport of salt and water in roots of the common reed (Phragmites australis Trin. ex Steudel)

To understand the root function in salt tolerance, radial salt and water transport were studied using reed plants growing in brackish habitat water with an osmotic pressure (πM ) of 0.63 MPa. Roots bathed in this medium exuded a xylem sap with NaCl as the major osmolyte and did so even at higher salt concentration (πM up to 1.3 MPa). Exudation was stopped after a small increase of πM (0.26 MPa) using polyethylene glycol 600 as osmolyte. The endodermis of fine lateral roots was found to be the main barrier to radial solute diffusion on an apoplastic path. Apoplastic salt transfer was proven by rapid replacement of stelar Na(+) by Li(+) in an isomolar LiCl medium. Water fluxes did not exert a true solvent drag on NaCl. Xylem sap concentrations of NaCl in basal internodes of transpiring culms were more than five times higher than in medial and upper ones. It was concluded that the radial NaCl flux was mainly diffusion through the apoplast, and radial water transport, because of the resistance of the cell wall matrix to convective mass flow, was confined to the symplast. Radial salt permeation in roots reduced the water stress exerted by the brackish medium.

SUN family proteins Sun4p, Uth1p and Sim1p are secreted from Saccharomyces cerevisiae and produced dependently on oxygen level

The SUN family is comprised of proteins that are conserved among various yeasts and fungi, but that are absent in mammals and plants. Although the function(s) of these proteins are mostly unknown, they have been linked to various, often unrelated cellular processes such as those connected to mitochondrial and cell wall functions. Here we show that three of the four Saccharomyces cerevisiae SUN family proteins, Uth1p, Sim1p and Sun4p, are efficiently secreted out of the cells in different growth phases and their production is affected by the level of oxygen. The Uth1p, Sim1p, Sun4p and Nca3p are mostly synthesized during the growth phase of both yeast liquid cultures and colonies. Culture transition to slow-growing or stationary phases is linked with a decreased cellular concentration of Sim1p and Sun4p and with their efficient release from the cells. In contrast, Uth1p is released mainly from growing cells. The synthesis of Uth1p and Sim1p, but not of Sun4p, is repressed by anoxia. All four proteins confer cell sensitivity to zymolyase. In addition, Uth1p affects cell sensitivity to compounds influencing cell wall composition and integrity (such as Calcofluor white and Congo red) differently when growing on fermentative versus respiratory carbon sources. In contrast, Uth1p is essential for cell resistance to boric acids irrespective of carbon source. In summary, our novel findings support the hypothesis that SUN family proteins are involved in the remodeling of the yeast cell wall during the various phases of yeast culture development and under various environmental conditions. The finding that Uth1p is involved in cell sensitivity to boric acid, i.e. to a compound that is commonly used as an important antifungal in mycoses, opens up new possibilities of investigating the mechanisms of boric acid's action.

Biosorption and biodegradation of Acid Orange 7 by Enterococcus faecalis strain ZL: optimization by response surface methodological approach

Reactive dyes account for one of the major sources of dye wastes in textile effluent. In this study, decolorization of the monoazo dye, Acid Orange 7 (AO7) by the Enterococcus faecalis strain ZL that isolated from a palm oil mill effluent treatment plant has been investigated. Decolorization efficiency of azo dye is greatly affected by the types of nutrients and the size of inoculum used. In this work, one-factor-at-a-time (method and response surface methodology (RSM) was applied to optimize these operational factors and also to study the combined interaction between them. Analysis of AO7 decolorization was done using Fourier transform infrared (FTIR) spectroscopy, desorption study, UV-Vis spectral analysis, field emission scanning electron microscopy (FESEM), and high performance liquid chromatography (HPLC). The optimum condition via RSM for the color removal of AO7 was found to be as follows: yeast extract, 0.1% w/v, glycerol concentration of 0.1% v/v, and inoculum density of 2.5% v/v at initial dye concentration of 100 mg/L at 37 °C. Decolorization efficiency of 98% was achieved in only 5 h. The kinetic of AO7 decolorization was found to be first order with respect to dye concentration with a k value of 0.87/h. FTIR, desorption study, UV-Vis spectral analysis, FESEM, and HPLC findings indicated that the decolorization of AO7 was mainly due to the biosorption as well as biodegradation of the bacterial cells. In addition, HPLC analyses also showed the formation of sulfanilic acid as a possible degradation product of AO7 under facultative anaerobic condition. This study explored the ability of E. faecalis strain ZL in decolorizing AO7 by biosorption as well as biodegradation process.

The actin-regulating kinase homologue MoArk1 plays a pleiotropic function in Magnaporthe oryzae

Endocytosis is an essential cellular process in eukaryotic cells that involves concordant functions of clathrin and adaptor proteins, various protein and lipid kinases, phosphatases and the actin cytoskeleton. In Saccharomyces cerevisiae, Ark1p is a member of the serine/threonine protein kinase (SPK) family that affects profoundly the organization of the cortical actin cytoskeleton. To study the function of MoArk1, an Ark1p homologue identified in Magnaporthe oryzae, we disrupted the MoARK1 gene and characterized the ΔMoark1 mutant strain. The ΔMoark1 mutant exhibited various defects ranging from mycelial growth and conidial formation to appressorium-mediated host infection. The ΔMoark1 mutant also exhibited decreased appressorium turgor pressure and attenuated virulence on rice and barley. In addition, the ΔMoark1 mutant displayed defects in endocytosis and formation of the Spitzenkörper, and was hyposensitive to exogenous oxidative stress. Moreover, a MoArk1-green fluorescent protein (MoArk1-GFP) fusion protein showed an actin-like localization pattern by localizing to the apical regions of hyphae. This pattern of localization appeared to be regulated by the N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins MoSec22 and MoVam7. Finally, detailed analysis revealed that the proline-rich region within the MoArk1 serine/threonine kinase (S_TKc) domain was critical for endocytosis, subcellular localization and pathogenicity. These results collectively suggest that MoArk1 exhibits conserved functions in endocytosis and actin cytoskeleton organization, which may underlie growth, cell wall integrity and virulence of the fungus.

Evaluation of phytoremediation potential of Tagetes patula L. for the degradation of textile dye Reactive Blue 160 and assessment of the toxicity of degraded metabolites by cytogenotoxicity

Tagetes patula is an annual flowering plant belonging to family Asteraceae. The present study deals with in vitro decolorization and remediation of a textile dye Reactive Blue 160 by T. patula. There was considerable (∼90%) decolorization of the dye within 4d of incubation, as confirmed by UV-vis, HPLC and FTIR analysis. The enzymes responsible for the remediation were lignin peroxidase, tyrosinase, laccase and NADH-DCIP reductase which were found in root tissues of the plantlets. GC-MS analysis of the products revealed formation of six metabolites such as sodium benzenesulfonate, 6-chloro 1,3,5-triazine-2,4-diamine, disodium benzene-1,4-disulfonate, sodium 3-amino-4-hydroxybenzenesulfonate, 1-phenylmethanediamine and sodium 4-amino-3-carboxybenzenesulfonate after phytoremediation of Reactive Blue 160. Based on the FTIR and GC-MS results, the possible pathway for the biodegradation of Reactive Blue 160 has been traced. The non-toxic nature of the degraded products was confirmed by performing cytogenotoxicity tests on root tip cells of growing Allium cepa.

Non-cell autonomous regulation of life cycle transitions in the model brown alga Ectocarpus

The model brown alga Ectocarpus has a haploid-diploid life cycle, involving alternation between two independent multicellular generations, the gametophyte and the sporophyte. Recent work has shown that alternation of generations is not determined by ploidy but is rather under genetic control, involving at least one master regulatory locus, OUROBOROS (ORO). Using cell biology approaches combined with measurements of generation-specific transcript abundance we provide evidence that alternation of generations can also be regulated by non-cell autonomous mechanisms. The Ectocarpus sporophyte produces a diffusible factor that causes major developmental reprogramming in gametophyte cells. Cells become resistant to reprogramming when the cell wall is synthetized, suggesting that the cell wall may play a role in locking an individual into the developmental program that has been engaged. A functional ORO gene is necessary for the induction of the developmental switch. Our results highlight the role of the cell wall in maintaining the differentiated generation stage once the appropriate developmental program has been engaged and also indicate that ORO is a key member of the developmental pathway triggered by the sporophyte factor. Alternation between gametophyte and sporophyte generations in Ectocarpus is surprisingly labile, perhaps reflecting an adaptation to the variable seashore environment inhabited by this alga.

Kinetics and thermodynamics of adsorption of Fuchsin acid on nickel oxide nanoparticles

NiO nanoparticle was used to adsorb fuchsin acid (FA) from aqueous solution. In the used concentration range of FA, its adsorption isotherms on NiO nanoparticles were three-region. NiO nanoparticle was prepared via the thermal decomposition of the tris(ethylenediamine)Ni(II) nitrate complex as a new precursor. In this work, effects of temperature, concentration, particle size, shaking rate, contact time, pH of the solution were investigated. Adsorption process was exothermic in the first and second regions and endothermic in the third region. Adsorption kinetics was studied by a number of equations including the KASRA, pseudo-first-order, pseudo-second-order, Elovich, Avrami and pore-diffusion equations. Adsorption acceleration and adsorption velocity values of this process were obtained by the KASRA equation and it was shown that with increase in FA concentration or temperature or shaking rate, initial adsorption velocity values of process increase.

Operational factors affecting the bioregeneration of mono-amine modified silica loaded with Acid Orange 7

In this study, the operational factors affecting the bioregeneration of AO7-loaded MAMS particles in batch system, namely redox condition, initial acclimated biomass concentration, shaking speed and type of acclimated biomass were investigated. The results revealed that with the use of mixed culture acclimated to AO7 under anoxic/aerobic conditions, enhancement of the bioregeneration efficiency of AO7-loaded MAMS and the total removal efficiency of COD could be achieved when the bio-decolorization and bio-mineralization stages were fully aerated with dissolved oxygen above 7 mg/L. Shorter duration of bioregeneration was achieved by using relatively higher initial biomass concentration and lower shaking speed, respectively, whereas variations of biomass concentration and shaking speed did not have a pronounced effect on the bioregeneration efficiency. The duration and efficiency of bioregeneration process were greatly affected by the chemical structures of mono-azo dyes to which the biomasses were acclimated.

Cereal β-glucan quantification with calcofluor-application to cell culture supernatants

The specific binding of the fluorescent dye calcofluor to cereal β-glucan results in increased fluorescence intensity of the formed complex and is in use for the quantification of β-glucan above a critical molecular weight (MW) by flow injection analysis. In this study, this method was applied in a fast and easy batch mode. In order to emphasize the spectral information of the emission spectra of the calcofluor/β-glucan complexes, derivative signals were calculated. A linear relationship was found between the amplitude of the second derivative signals and the β-glucan concentration between 0.1 and 0.4 μg/mL. The low detection limit of this new method (0.045 μg/mL) enabled its use to study the transport of cereal β-glucans over differentiated Caco-2 cell monolayers. Additionally, the method was applied to quantify β-glucan in arabinoxylan samples, which correlated well with data by an enzyme based method.

Evaluation of adsorption characteristics of an anionic azo dye Brilliant Yellow onto hen feathers in aqueous solutions

PURPOSE AND AIM: Removal of an anionic azo dye Brilliant Yellow has been carried out from its aqueous solutions by using hen feathers as potential adsorbent.

MATERIALS AND METHODS

Hen feathers procured from local poultry were cut, washed, and activated. Detailed chemical and physical analysis of hen feathers and its characterization through scanning electron microscopy, X-ray diffraction, and infrared measurements have been made. Procured dye has been adsorbed over under batch measurements and adsorption process is monitored using UV spectrophotometer.

RESULTS

Optimum parameters for the adsorption of Brilliant Yellow over hen feathers have been determined by studying the effect of pH, temperature, concentration of dye, and amount of adsorbent. On the basis of Langmuir adsorption, isotherms feasibility of the ongoing adsorption has been ascertained and thermodynamic parameters have been calculated. Attempts have also been made to verify Freundlich, Tempkin, and Dubinin–Radushkevich adsorption isotherm models. It is found that during adsorption, uniform distribution of binding energy takes place due to interaction of the dye molecules and the ongoing adsorption process is chemisorptions. The kinetic measurements indicate dominance of pseudo-second-order process during the adsorption. The mathematical treatment on the kinetic data reveals the rate-determining step to be governed through particle diffusion at 8 × 10−5 M and involvement of film diffusion mechanism at higher concentration at temperatures at all the temperatures.

CONCLUSIONS

The developed process is highly efficient and it can be firmly concluded that hen feather exhibits excellent adsorption capacity towards hazardous azo dye Brilliant Yellow.

Covalent and non-covalent binding in the ion/ion charge inversion of peptide cations with benzene-disulfonic acid anions

Protonated angiotensin II and protonated leucine enkephalin-based peptides, which included YGGFL, YGGFLF, YGGFLH, YGGFLK and YGGFLR, were subjected to ion/ion reactions with the doubly deprotonated reagents 4-formyl-1,3-benzenedisulfonic acid (FBDSA) and 1,3-benzenedisulfonic acid (BDSA). The major product of the ion/ion reaction is a negatively charged complex of the peptide and reagent. Following dehydration of [M + FBDSA-H](-) via collisional-induced dissociation (CID), angiotensin II (DRVYIHPF) showed evidence for two product populations, one in which a covalent modification has taken place and one in which an electrostatic modification has occurred (i.e. no covalent bond formation). A series of studies with model systems confirmed that strong non-covalent binding of the FBDSA reagent can occur with subsequent ion trap CID resulting in dehydration unrelated to the adduct. Ion trap CID of the dehydration product can result in cleavage of amide bonds in competition with loss of the FBDSA adduct. This scenario is most likely for electrostatically bound complexes in which the peptide contains both an arginine residue and one or more carboxyl groups. Otherwise, loss of the reagent species from the complex, either as an anion or as a neutral species, is the dominant process for electrostatically bound complexes. The results reported here shed new light on the nature of non-covalent interactions in gas phase complexes of peptide ions that can be used in the rationale design of reagent ions for specific ion/ion reaction applications.

Conostegia xalapensis (Melastomataceae): an aluminum accumulator plant

In acidic soils, an excess of Al³⁺ is toxic to most plants. The Melastomataceae family includes Al-accumulator genera that tolerate high Al³⁺ by accumulating it in their tissues. Conostegia xalapensis is a common shrub in Mexico and Central America colonizing mainly disturbed areas. Here, we determined whether C. xalapensis is an Al accumulator, and whether it has internal tolerance mechanisms to Al. Soil samples collected from two pastures in the state of Veracruz, Mexico, had low pH and high Al³⁺ concentrations along with low Ca²⁺ levels. Leaves of C. xalapensis from pastures showed up to 19,000 mg Al kg⁻¹ DW (dry weight). In laboratory experiments, 8-month-old seedlings treated with 0.5 and 1.0 mM AlCl₃ for 24 days showed higher number of lateral roots and biomass. Pyrocatechol violet and hematoxylin staining evidenced that Al localized in epidermis and mesophyll cells in leaves and in epidermis and vascular pith in roots. Scanning electron microscope-energy dispersive X-ray microanalysis of Al-treated leaves corroborated that Al is in abaxial and adaxial epidermis and in mesophyll cells (31.2%) in 1.0 mM Al-treatment. Roots of Al-treated plants had glutathione reductase (EC 1.6.4.2) and superoxide dismutase (EC 1.15.1.1) activity higher, and low levels of O₂*⁻ and H₂O₂. C. xalapensis is an Al-accumulator plant that can grow in acidic soils with higher Al³⁺ concentrations, and can be considered as an indicator species for soils with potential Al toxicity.

[Optimization on decoloration conditions of anthraquinone dyes by laccase from Amillariella mellea]

Laccase extracted from the Amillariella mellea fermentation catalytic decolored on two common anthraquinone dyes: Reactive Brilliant Blue KN-R and Reactive Brilliant Blue X-BR which is broadly used in the printing and dyeing industry and obtained the optimal catalytic decolorizing conditions. The results showed that optimum temperature of Reactive Brilliant Blue KN-R decolorization was 30 degrees C, the optimum dye concentrations was 80 mg x L(-1), the optimum enzyme dosage was 0.25 U x mL(-1), and the optimum pH was 5. Under this optimal conditions, the maximum decolorization rate of Reactive Brilliant Blue KN-R was over 90%. The optimum temperature Reactive Brilliant Blue X-BR decolorization was 30 degrees C, the optimum dye concentrations was 50 mg x L(-1), the optimum enzyme dosage was 0.5 U x mL(-1), and the optimum was pH 4. Under the optimal conditions, the maximum decolorization rate of Reactive Brilliant Blue X-BR was over 70%. The decolorization on the two common industrial dyes by crude enzyme from Amillariella mellea fermentation obtained a good results. The results indicated that the decoloration on anthraquinone dyes by laccase from Amillariella mellea has a potential value in the printing and dyeing industry.

Decolorization of orange II using an anaerobic sequencing batch reactor with and without co-substrates

We investigated the decolorization of Orange II with and without the addition of co-substrates and nutrients under an anaerobic sequencing batch reactor (ASBR). The increase in COD concentrations from 900 to 1750 to 3730 mg/L in the system treating 100 mg/L of Orange II-containing wastewater enhanced color removal from 27% to 81% to 89%, respectively. In the absence of co-substrates and nutrients, more than 95% of decolorization was achieved by the acclimatized anaerobic microbes in the bioreactor treating 600 mg/L of Orange II. The decrease in mixed liquor suspended solids concentration by endogenous lysis of biomass preserved a high reducing environment in the ASBR, which was important for the reduction of the Orange II azo bond that caused decolorization. The maximum decolorization rate in the ASBR was approximately 0.17 g/hr in the absence of co-substrates and nutrients.

Differential fate of metabolism of a sulfonated azo dye Remazol Orange 3R by plants Aster amellus Linn., Glandularia pulchella (Sweet) Tronc. and their consortium

Plant consortium-AG of Aster amellus Linn. and Glandularia pulchella (Sweet) Tronc. showed complete decolorization of a dye Remazol Orange 3R in 36 h, while individually A. amellus and G. pulchella took 72 and 96 h respectively. Individually A. amellus showed induction in the activities of enzymes veratryl alcohol oxidase and DCIP reductase after degradation of the dye while G. pulchella showed induction of laccase and tyrosinase, indicating their involvement in the dye metabolism. Consortium-AG showed induction in the activities of lignin peroxidase, veratryl alcohol oxidase, laccase, tyrosinase and DCIP reductase. Two different sets of induced enzymes from A. amellus and G. pulchella work together in consortium-AG resulting in faster degradation of the dye. The degradation of the dye into different metabolites was confirmed using High Performance Liquid Chromatography and Fourier Transform Infra Red Spectroscopy. Gas Chromatography Mass Spectroscopy analysis identified four metabolites of dye degradation by A. amellus as acetamide, benzene, naphthalene and 3-diazenylnaphthalene-2-sulfonic acid, four metabolites by G. pulchella as acetamide, 3-diazenyl-4-hydroxynaphthalene-2-sulfonic acid, naphthalen-1-ol and (ethylsulfonyl)benzene, while two metabolites by consortium-AG as 2-(phenylsulfonyl)ethanol and N-(naphthalen-2-yl)acetamide. The non-toxic nature of the metabolites of Remazol Orange 3R degradation was revealed by phytotoxicity studies.

Degradation of the synthetic dye amaranth by the fungus Bjerkandera adusta Dec 1: inference of the degradation pathway from an analysis of decolorized products

We examined the degradation of amaranth, a representative azo dye, by Bjerkandera adusta Dec 1. The degradation products were analyzed by high performance liquid chromatography (HPLC), visible absorbance, and electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS). At the primary culture stage (3 days), the probable reaction intermediates were 1-aminonaphthalene-2,3,6-triol, 4-(hydroxyamino) naphthalene-1-ol, and 2-hydroxy-3-[2-(4-sulfophenyl) hydrazinyl] benzenesulfonic acid. After 10 days, the reaction products detected were 4-nitrophenol, phenol, 2-hydroxy-3-nitrobenzenesulfonic acid, 4-nitrobenzene sulfonic acid, and 3,4'-disulfonyl azo benzene, suggesting that no aromatic amines were created. Manganese-dependent peroxidase activity increased sharply after 3 days culture. Based on these results, we herein propose, for the first time, a degradation pathway for amaranth. Our results suggest that Dec 1 degrades amaranth via the combined activities of peroxidase and hydrolase and reductase action.

Interaction of sorafenib and cytochrome P450 isoenzymes in patients with advanced melanoma: a phase I/II pharmacokinetic interaction study

BACKGROUND

In vitro data indicate that the sorafenib is a moderate inhibitor of cytochrome P450 (CYP) enzymes, including CYP3A4, CYP2C19, and CYP2D6. This phase I/II study in patients with advanced melanoma evaluated the potential effect of sorafenib on the pharmacokinetics of midazolam, omeprazole, and dextromethorphan, specific substrates of CYP3A4, CYP2C19, and CYP2D6, respectively.

METHODS

Twenty-one patients received sorafenib 400 mg twice daily for 28 consecutive days. On days 1 and 28, a cocktail containing midazolam 2 mg, omeprazole 20 mg, and dextromethorphan 30 mg was administered. Pharmacokinetic analyses were performed on day 1 without sorafenib and day 28 after steady-state sorafenib exposure; sorafenib pharmacokinetics were evaluated on day 28. We defined an interaction to be excluded if the 90% confidence interval of the ratio of all day 28:day 1 analyses fell within a range from 0.80 to 1.25.

RESULTS

In all, 18 patients were evaluable. On day 28, area under the plasma concentration-time curve from time 0 to 12 h (AUC(0-12)) and maximum plasma concentration (C(max)) for sorafenib were 38.1 mg h/l and 4.9 mg/l, respectively. Day 28:day 1 ratios for AUC from time 0 extrapolated to infinity (AUC(0-inf)) and C(max) for midazolam were 0.85 and 0.98, respectively. Day 28:day 1 ratio for 5-OH-omeprazole:omeprazole plasma concentration at 3 h postdose was 1.26, slightly outside of the 0.80-1.25 range. Thus, an interaction could not be excluded, but is considered unlikely to be clinically significant. Day 28:day 1 ratio for dextromethorphan:dextrorphan concentration in urine was 0.94. Sorafenib had an acceptable safety profile. The most frequently observed grade 3-4 toxicities in cycle 1 included elevated lipase (19%) and hypertension (10%).

CONCLUSIONS

In this patient population, our results demonstrate that exposures of probes of CYP3A4, CYP2D6, or CYP2C19 activity are potentially altered by administration of sorafenib at 400 mg twice daily. However, these differences are sufficiently small that a clinically significant inhibition or induction of these important drug metabolizing P450 isoenzymes is unlikely. Clinical and, where possible, drug level monitoring may still be appropriate for drugs of narrow therapeutic range co-administered with sorafenib.

Multidrug resistance protein 2 implicates anticancer drug-resistance to sorafenib

Sorafenib and sunitinib is a small molecule inhibitor of certain receptor tyrosine kinases, and have improved outcomes for patients with advanced renal cell carcinoma. Inhibitory concentration of 50% cell growth of sorafenib significantly rose to 6.4-fold in a multidrug resistance protein 2 (MRP2) transfected cell line versus control cell line. The concentration of sorafenib was significantly decreased to 74% of control cells after 3 h treatment. In contrast, a tyrosine kinase inhibitor sunitinib did not show alteration of inhibitory concentration of 50% cell growth and accumulation into the cells of MRP2 transfected cells. The present study suggest that sorafenib is a substrate for MRP2, suggesting that MRP2 may implicate drug resistance to sorafenib.

Quantitation of sorafenib and its active metabolite sorafenib N-oxide in human plasma by liquid chromatography-tandem mass spectrometry

A simple and rapid method with high performance liquid chromatography/tandem mass spectrometry is described for the quantitation of the kinase inhibitor sorafenib and its active metabolite sorafenib N-oxide in human plasma. A protein precipitation extraction procedure was applied to 50 μL of plasma. Chromatographic separation of the two analytes, and the internal standard [(2)H(3)(13)C]-sorafenib, was achieved on a C(18) analytical column and isocratic flow at 0.3 mL/min for 4 min. Mean within-run and between-run precision for all analytes were <6.9% and accuracy was <5.3%. Calibration curves were linear over the concentration range of 50-10,000 ng/mL for sorafenib and 10-2500 ng/mL for sorafenib N-oxide. This method allows a specific, sensitive, and reliable determination of the kinase inhibitor sorafenib and its active metabolite sorafenib N-oxide in human plasma in a single analytical run.