Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.10.3.2 (laccase)
4,656 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Selected strains of three species of white rot fungi, Pleurotus ostreatus, Phanerochaete chrysosporium and Trametes versicolor, were grown in sterilized soil from straw inocula. The respective colonization rates and mycelium density values decreased in the above mentioned order. Three- and four-ringed PAHs at 50 ppm inhibited growth of fungi in soil to some extent. The activities of fungal MnP and laccase (units per g dry weight of straw or soil), extracted with 50 mM succinate-lactate buffer (pH 4.5), were 5 to 20-fold higher in straw compared to soil. The enzyme activities per g dry soil in P. ostreatus and T. versicolor were similar, in contrast to P. chrysosporium, where they were extremely low. Compared to the aerated controls, P. ostreatus strains reduced the levels of anthracene, pyrene and phenanthrene by 81-87%, 84-93% and 41-64% within 2 months, respectively. During degradation of anthracene, all P. ostreatus strains accumulated anthraquinone. PAH removal rates in P. chrysosporium and T. versicolor soil cultures were much lower.
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PMID:Extracellular oxidative enzyme production and PAH removal in soil by exploratory mycelium of white rot fungi. 1049 84

The ability of the ligninolytic fungus Trametes trogii to degrade in vitro different xenobiotics (PCBs, PAHs and dyes) was evaluated. Either 200 ppm of a PCB mixture (Aroclor 1150) or 160 ppm of an industrial PAH mixture (10% V/V of PAHs, principal components hexaethylbenzene, naphthalene, 1-methyl naphthalene, acenaphthylene, anthracene, fluorene and phenanthrene), were added to trophophasic and idiophasic cultures growing in a nitrogen limited mineral medium (glucose/asparagine) and in a complex medium (malt extract/glucose). Gas-liquid chromatography proved that within 7 to 12 d more than 90% of the organopollutants added were removed. The decrease in absorbance at 620 nm demonstrated that cultures of this fungus were able to transform 80% of the dye Anthraquinone-blue (added at a concentration of 50 ppm) in 1.5 h. Enzyme estimations indicated high activity of laccase (up to 0.55 U/mL), as well as lower production of manganese-peroxidase. Laccase activity, detected in all the conditions assayed, could be implicated in the degradation of these organopollutants. Considering the results obtained, T. trogii seems promising for detoxification.
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PMID:Degradation of environmental pollutants by Trametes trogii. 1241 98

The influence of the white rot fungus Pleurotus ostreatus on the degradation of selected poly- and heterocyclic aromatic hydrocarbons (referred to as polycyclic aromatic hydrocarbons [PAHs]) in soil was investigated under field conditions representing the Northern temperate zone. Pleurotus ostreatus was added to two contaminated soils in the form of homogenized refuse from the commercial production of fungus. The soils were collected from a former shipyard (the B&W soil) and underneath a former coal tar storage at an old asphalt factory in Denmark (the Ringe soil). Treatments (control, soil mixed with autoclaved sawdust medium, and soil mixed with P. ostreatus refuse) were set up in triplicate in concrete cylinders (height, 50 cm; diameter, 60 cm). The activity of P. ostreatus was measured as laccase activity and phenanthrene (PHE)- and pyrene (PYR)-degrading bacteria were enumerated. Twenty-one different PAHs were quantified. After nine weeks the concentrations of the 3-, 4-, 5-, and 6-ring PAHs in the Ringe soil were reduced by 78, 41, and 4%, respectively. These reductions corresponded with high initial laccase activity, a decrease in pH caused by the fungus, and an increase in the number of PHE- and PYR-degrading bacteria. No significant PAH degradation was observed in the B&W soil. Reasons for the difference in performance of P. ostreatus in the two soils are discussed in terms of soil histories and bioavailability. The use of P. ostreatus refuse holds promising potential for bioremediation purposes.
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PMID:Bioaugmentation of tar-contaminated soils under field conditions using Pleurotus ostreatus refuse from commercial mushroom production. 1268 99

Spent mushroom compost (SMC) is a bulky waste byproduct of mushroom industry and produced abundantly. The SMC of Pleurotus pulmonarius immobilized laccase (0.88 mmoles min(-1) g(-1)) and manganese peroxidase (0.58 mmoles min(-1) g(-1)) of which the optimal temperatures were 45 and 75 degrees C, respectively. In laboratory test, complete degradative removal of individual naphthalene, phenanthrene, benzo[a]pyrene and benzo[g,h,i]perylene (200 mg PAH kg(-1) sandy-loam soil) by 5% SMC was obtained in two days under continuous shaking at 80 degrees C. The SMC-treated PAH samples had significantly reduced or removed their toxicities as revealed by the Microtox bioassay. These results were confirmed by gas chromatography-mass spectrometry analysis on the breakdown products. A phthalic derivative which is reported as a degradative product of PAHs by ozonation or ligninolysis was also detected in the SMC-treated samples. The results demonstrate the potential in employing SMC in ex situ bioremediation.
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PMID:Use of spent mushroom compost to bioremediate PAH-contaminated samples. 1286 86

The white-rot fungus Irpex lacteus has been reported to be an efficient degrader of polycyclic aromatic hydrocarbons, polychlorinated biphenyls and pentachlorophenol. The fungus produces ligninolytic enzymes laccase, lignin peroxidase and manganese peroxidase (MnP), the latter being the major one produced. MnP was purified using anion exchange and size exclusion chromatography. SDS-PAGE showed the purified MnP to be a monomeric protein of 37 kDa (37.5 kDa using MALDI-TOF) with an isoelectric point at 3.55. The pH optimum was relatively broad, from 4.0 to 7.0 with a peak at pH 5.5. Kinetic constants K(m) were 8 microM for H(2)O(2) and 12 or 31 microM for Mn(2+) depending on the substrate. The enzyme did not perform oxidation in the absence of H(2)O(2) or Mn(2+). MnP was active at 5-70 degrees C with an optimum between 50-60 degrees C. At temperatures above 65 degrees C the enzyme rapidly lost activity. Degradation of four representatives of PAHs (phenanthrene, anthracene, fluoranthene, and pyrene) was tested and the enzyme showed the ability to degrade them in vitro. Major degradation products of anthracene were identified. The results confirm the role of MnP in PAH degradation by I. lacteus, including cleavage of the aromatic ring.
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PMID:Purification of a new manganese peroxidase of the white-rot fungus Irpex lacteus, and degradation of polycyclic aromatic hydrocarbons by the enzyme. 1625 12

The ability of a Deuteromycete fungus, Cladosporium sphaerospermum, previously isolated from soil of an aged gas manufacturing plant, to degrade polycyclic aromatic hydrocarbons was investigated. This strain was able to degrade PAHs in non-sterile soils (average 23%), including high molecular weight PAHs, after 4 weeks of incubation. In a microcosm experiment, PAH depletion was clearly correlated to fungal establishment. In liquid culture, this strain degraded rapidly benzo(a)pyrene during its early exponential phase of growth (18% after 4 days of incubation). Among extracellular ligninolytic enzyme activities tested, only laccase activity was detected in liquid culture in the absence or in presence of benzo(a)pyrene. C. sphaerospermum might be a potential candidate for an effective bioremediation of aged PAH-contaminated soils.
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PMID:Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by Cladosporium sphaerospermum isolated from an aged PAH contaminated soil. 1632 56

PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H(2)O, CO(2) (aerobic) or CH(4) (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate can be enhanced by physical/chemical pretreatment of contaminated soil. Addition of biosurfactant-producing bacteria and light oils can increase the bioavailability of PAHs and metabolic potential of the bacterial community. The supplementation of contaminated soils with compost materials can also enhance biodegradation without long-term accumulation of extractable polar and more available intermediates. Wetlands, too, have found an application in PAH removal from wastewater. The intensive biological activities in such an ecosystem lead to a high rate of autotrophic and heterotrophic processes. Aquatic weeds Typha spp. and Scirpus lacustris have been used in horizontal-vertical macrophyte based wetlands to treat PAHs. An integrated approach of physical, chemical, and biological degradation may be adopted to get synergistically enhanced removal rates and to treat/remediate the contaminated sites in an ecologically favorable process.
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PMID:Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review. 1944 41

High potential purified Trametes trogii laccase has been studied as a biocatalyst for oxygen cathodes composed of layer-by-layer self-assembled thin films by sequential immersion of mercaptopropane sulfonate-modified Au electrode surfaces in solutions containing laccase and osmium-complex bound to poly(allylamine), (PAH-Os). The polycation backbone carries the Os redox relay, and the polyanion is the enzyme adsorbed from a solution of a suitable pH so that the protein carries a net negative charge. Enzyme thin films were characterized by quartz crystal microbalance, ellipsometry, cyclic voltammetry, and oxygen reduction electrocatalysis under variable oxygen partial pressures with a rotating disk electrode. New kinetic evidence relevant to biofuel cells is presented on the detection of traces of H(2)O(2), intermediate in the O(2) reduction, with scanning electrochemical microscopy (SECM). Furthermore the inhibitory effect of peroxide on the biocatalytic current resulted in abnormal current dependence on the O(2) partial pressure and peak shape with hysteresis in the polarization curves under stagnant conditions, which is offset upon stirring with the RDE. The new kinetic evidence reported in the present work is very relevant for the operation of biofuel cells under stagnant conditions of O(2) mass transport.
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PMID:Layer-by-layer self-assembled osmium polymer-mediated laccase oxygen cathodes for biofuel cells: the role of hydrogen peroxide. 2069 79

The aim of this study was to evaluate the effects of chemically dispersed oil on an economically and ecologically important species inhabiting coasts and estuaries, the Pacific oyster Crassostrea gigas. Studies were carried out with juveniles, known to generally be more sensitive to environmental stress than adults. A set of enzyme activities involved in immune defence mechanisms and detoxification processes, i.e. superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), catecholase-type phenoloxidase (PO), laccase-type PO and lysozyme were analysed in different oyster tissues, i.e. the gills, digestive gland and mantle, and in the plasma and the haemoycte lysate supernatant (HLS) of the haemolymph. Results indicated that total PAH body burdens were 2.7 times higher in the presence than in the absence of the chemical dispersant. After 2 days of exposure to chemically dispersed oil, alkylated naphthalenes accounted for 55% of the total PAH body burden, whereas alkylated fluorenes and alkylated dibenzothiophenes accounted for 80% when the chemical dispersant was absent. Importantly, a higher number of enzyme activities were modified when oil was chemically dispersed, especially in the plasma and gills. Moreover, independently of the presence or absence of chemical dispersant, oil exposure generally inhibited enzyme activities in the gills and plasma, while they were generally activated in the mantle and haemocytes. These results suggest that the gills and plasma constitute sensitive compartments in C. gigas, and that the mantle and haemocytes may play an important role in protection against xenobiotics. Among the six enzyme activities that were analysed in these body compartments, five were modulated in the chemical dispersion (CD) treatment while only half of the enzyme activities were modulated in the mechanical dispersion treatment. Furthermore, CD treatment effects were often observed following exposure, but also during depuration periods. These results suggest that immune and/or detoxification responses are likely to be affected when dispersants are used to treat oil spills in shallow waters.
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PMID:Enhanced immunological and detoxification responses in Pacific oysters, Crassostrea gigas, exposed to chemically dispersed oil. 2166 40

Trichoderma asperellum H15, a previously isolated strain characterized by its high tolerance to low (LMW) and high molecular weight (HMW) PAHs, was tested for its ability to degrade 3-5 ring PAHs (phenanthrene, pyrene, and benzo[a]pyrene) in soil microcosms along with a biostimulation treatment with sugarcane bagasse. T. asperellum H15 rapidly adapted to PAH-contaminated soils, producing more CO2 than uncontaminated microcosms and achieving up to 78 % of phenanthrene degradation in soils contaminated with 1,000 mg Kg(-1) after 14 days. In soils contaminated with 1,000 mg Kg(-1) of a three-PAH mixture, strain H15 was shown to degrade 74 % phenanthrene, 63 % pyrene, and 81 % of benzo[a]pyrene. Fungal catechol 1,2 dioxygenase, laccase, and peroxidase enzyme activities were found to be involved in the degradation of PAHs by T. asperellum. The results demonstrated the potential of T. asperellum H15 to be used in a bioremediation process. This is the first report describing the involvement of T. asperellum in LMW and HMW-PAH degradation in soils. These findings, along with the ability to remove large amounts of PAHs in soil found in the present work provide enough evidence to consider T. asperellum as a promising and efficient PAH-degrading microorganism.
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PMID:Degradation of polycyclic aromatic hydrocarbons in soil by a tolerant strain of Trichoderma asperellum. 2510 16


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