Aim of this work was to investigate the ability of Lentinus (Panus) tigrinus to degrade and detoxify a chlorobenzoate (CBA) mixture composed of mono-, di- and tri-chlorinated isomers. The degradation process was investigated as a function of both the growing medium (i.e. low N Kirk's and malt extract-glucose medium) and cultivation conditions (i.e. stationary and shaken cultures). The majority of CBAs were quantitatively degraded within the early 15 d from spiking with the notable exception of the double ortho-chlorinated compounds, 2,6-di-, 2,3,6-tri- and 2,4,6-tri-CBA. Analysis of the degradation intermediates indicated the occurrence of side chain reduction, hydroxylation and methylation reactions. Although CBAs stimulated laccase production, in vitro experiments with a purified L. tigrinus laccase isoenzyme demonstrated its inability to participate in the initial attack on CBAs even in the presence of redox mediators; similar results were found with a Mn-peroxidase isoenzyme. Conversely, prompt degradation was observed upon 1h incubation of CBAs with a purified microsomal fraction containing cytochrome P-450 monooxygenase. The nature of some reaction products (i.e. hydroxylated derivatives), the dependency of the reaction on NADPH and its susceptibility to either CO or piperonyl butoxide inhibition confirmed the involvement of L. tigrinus cytochrome P-450 in the early steps of CBA degradation.

• MeSH
• Aliivibrio fischeri metabolismus   MeSH
• biodegradace MeSH
• biomasa MeSH
• chemické látky znečišťující vodu analýza   metabolismus   MeSH
• chlor chemie   MeSH
• chlorbenzoáty analýza   metabolismus   MeSH
• čištění vody metody   MeSH
• kultivační média metabolismus   MeSH
• kyslík chemie   MeSH
• lakasa metabolismus   MeSH
• Lentinula metabolismus   MeSH
• luminiscence MeSH
• mikrozomy metabolismus   MeSH
• peroxidasy MeSH
• substrátová specifita MeSH
• systém (enzymů) cytochromů P-450 metabolismus   MeSH
• testy toxicity MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Sequential supercritical fluid extraction together with a two-site desorption model were employed to estimate the bioaccessible fraction of polycyclic aromatic hydrocarbons (PAHs) in four historically contaminated soils. The ecotoxicity of the soils was assayed by four different contact tests. The same soils were exposed to exhaustive extraction and the extracts were returned to the soils to ensure total 100% bioaccessibility of the pollutants. Then the soils were assayed again. Statistical evaluation revealed that the predicted bioaccessible PAHs generally correlated with the ecotoxicity responses of the tests. The estimated bioaccessible fractions varied from 10 to 98%. This value increased for PAHs with higher lipophilicity and showed no correlation with the organic carbon content in the soils. The ecotoxicity tests in the study indicated different sensitivity toward PAHs and the tests employing Heterocypris incongruens and Eisenia fetida were found to be more suitable than Lemna minor and Vibrio fischeri. Mortality and growth inhibition of ostracods correlated with all the types of PAHs and earthworm growth inhibition and mortality were preferentially sensitive to PAHs with only 3-4 aromatic rings. Determination of the biota-soil accumulation factors indicated that the earthworm growth inhibition corresponded to increased accumulation of PAHs in the earthworm tissue.

• MeSH
• Aliivibrio fischeri účinky léků   metabolismus   MeSH
• Araceae účinky léků   růst a vývoj   MeSH
• korýši účinky léků   růst a vývoj   MeSH
• látky znečišťující půdu analýza   toxicita   MeSH
• luminiscence MeSH
• Oligochaeta účinky léků   růst a vývoj   MeSH
• polycyklické aromatické uhlovodíky analýza   toxicita   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH