Institute of Biochemistry and Physiology of Microorganisms of Russian Academy of Sciences, Pushchino Moscow region. leont@ibpm.serpukhov.su
Abstract
Laccase from the white rot fungus Coriolus versicolor was immobilized on Celite R-637 by covalent binding with glutaraldehyde. After a sharp primary decline in activity (up to 50%), the retained enzyme activity was stable over a storage period of 33 days at 4 degrees C. A comparative study of soluble and immobilized laccases revealed the increased resistance of immobilized enzyme to the unfavourable effects of alkaline pH, high temperature and the action of inhibitors. A combination of these properties of immobilized laccase resulted in the ability to oxidize 2,4,6-trichlorophenol (2,4,6-TCP) at 50 degrees C at pH 7.0. The reactions of soluble and immobilized laccase with 2,4,6-TCP were examined in the presence and absence of redox mediators. 3,5-Dichlorocatechol, 2,6-dichloro-1,4-benzoquinone and 2,6-dichloro-1,4-hydroquinone were found to be the primary products of 2,4,6-TCP oxidation by laccase; oligo- and polymeric compounds were also found.
Departamento de Biología Aplicada, CITE II-B, Universidad de Almeria, La Cañada de San Urbano, Spain. mllopez@ual.es
Abstract
The mineralisation and the humification of organic matter (OM) in sterile horticultural plant wastes inoculated with Coriolus versicolor or Phanerochaete flavido-alba was investigated under different aeration rates in order to determine their efficacy as potential inoculants for composting. The change in elemental composition, lignin content and OM fractions was analysed during a 90-day incubation. Both fungi degraded 30% of lignin at low aeration rates. Different aeration rates led to significant changes in OM mineralisation induced by C. versicolor, but did not have noticeable effect on P. flavido-alba activity. The mineralisation was more effectively carried out by P. flavido-alba than by C. versicolor. Lignin degradation and the linked humification process were equally achieved by the two fungi and were enhanced in aerated conditions. The fungi analysed may facilitate the composting of lignocellulosic wastes by means of an increase in substrate bioavailability and OM humification.
Production of an extracellular pectinase by wood-rot fungi of the genus Bjerkandera and Coriolus was studied. The active producers B. adusta 40 and C. versicolor 24 were selected. The dynamics of production of pectinase and effects of temperature, initial pH, humidity of the medium and addition of nitrogen sources on the biosynthesis of pectinase were studied.
Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
Abstract
Using a reverse-transcription polymerase chain reaction (RT-PCR) technique, cytochrome P450 genes were cloned from the lignin-degrading basidiomycete, Coriolus versicolor. One possible P450 gene was identified, which consisted of 1,672 nucleotides and a poly(A) tail and encoded a deduced protein containing 449 amino acids. The deduced amino acid sequence revealed the presence of the P450 heme-binding motif, strongly suggesting that this protein belongs to the P450 superfamily, then designated CYP512A1. The deduced protein showed sequential similarity to other known P450s from several micro-organisms, such as Aspergillus terreus, Gibberella fujikuroi, and Neurospora crassa, with 30-35% identity. Since the identity of the amino id sequence was less than 40% with any other P450s, this protein was suggested to be the first member of a new family of cytochrome P450. In addition, a differential display RT-PCR analysis showed the expression of the other P450 genes, which were up-regulated by the addition of dibenzothiophene and 4-methyldibenzothiophene-5-oxide. Using the 5′ rapid amplification of cDNA ends method, a 520-nucleotide sequence, including the P450 motif-coding region, was determined for one clone. The deduced protein showed high similarity to CYP512A1 but less than 40% identity with P450s from other organisms. A chemical stress-responsive expression of P450 is suggested for the first time in basidiomycetes.
Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
Abstract
The fungal conversions of sulfur-containing heterocyclic compounds were investigated using the lignin-degrading basidiomycete Coriolus versicolor. The fungus metabolized a series of sulfur compounds–25 structurally related thiophene derivatives–via several different pathways. Under primary metabolic conditions, C. versicolor utilized thiophenes, such as 2-hydroxymethyl-, 2-formyl-, and 2-carboxyl-thiophenes, as a nutrient sulfur source for growth; thus, the fungus degraded these compounds more effectively in a non-sulfur-containing medium than in conventional medium. The product analysis revealed that several redox reactions, decarboxylation reactions, and C-S cleavage reactions were involved in the fungal conversion of non-aromatic thiophenes. On the other hand, benzothiophene (BT) and dibenzothiophene (DBT) skeletons were converted to water-soluble products. All the products and metabolic intermediates were more hydrophilic than the starting substrates. These metabolic actions seemed to be a chemical stress response against exogenously added xenobiotics. These metabolic reactions were optimized under ligninolytic conditions, also suggesting the occurrence of a fungal xenobiotic response. Furthermore, the fungus converted a series of BTs and DBTs via several different pathways, which seemed to be controlled by the chemical structure of the substrates. DBT, 4-methylDBT, 4, 6-dimethylDBT, 2-methylBT, and 7-methylBT were immediately oxidized to their S-oxides. BTs and DBTs with the hydroxymethyl substituent were converted to their xylosides without S-oxidation. Those with carboxyl and formyl substituents were reduced to form a hydroxymethyl group, then xylosidated. These observations strongly suggested the involvement of a fungal substrate-recognition and metabolic response mechanism in the metabolism of sulfur-containing heterocyclic compounds by C. versicolor.
Department of Science, Faculty of Education, Inonu University, Malatya, Turkey. sskahraman@inonu.edu.tr
Abstract
Laccase is among the major enzymes of white rot fungi involved in lignocellulose degradation. The present paper reports its production by two white rot fungi (Coriolus versicolor, Funalia trogii) under different nutritional conditions. Various synthetic culture media and natural culture medium (molasses wastewater) were tested. Enzyme production in various synthetic culture media, molasses wastewater (vinasse) culture medium and in the absence or presence of cotton stalk supplements showed that vinasse culture medium was a better laccase-inducer medium than the synthetic culture medium. Addition of cotton stalk to various media enhanced the enzyme production. The highest laccase activity was obtained in vinasse culture medium with cotton stalk.
School of Biological & Chemical Sciences, Birkbeck College, University of London, United Kingdom.
Abstract
Adult females of Xestobium rufovillosum de Geer demonstrated anemotactic orientation when exposed to an odor plume containing volatiles generated by wood-decaying fungi (Coriolus versicolor, Donkioporia expansa) and decayed oak wood (Quercus petraea, Quercus robur). They did not orient towards undecayed oak wood, beech (Fagus sylvatica), or pine wood (Pinus sylvestris). Although all insects tested showed anemotactic orientation, responses were nonlinear with respect to insect age. Adult females more readily oriented upwind when they were between 10 and 16 days old. Oviposition choice bioassays showed that ovipositing females would preferentially oviposit on extract-treated cellulose paper discs that had been treated with various strains of the wood-decaying fungus, Donkioporia expansa. HPLC-fractionated mycelial extracts were attractive to ovipositing deathwatch beetles, whereas HPLC-fractionated fungal broth extracts were repellent to ovipositing females. The implications of these results are discussed in the context of timber pest management in historically important buildings.
Laboratory for Molecular Pharmacology, Department of Hygiology, First Military Medical University, Guangzhou 510515, China. songlc@fimmu.edu.cn
Abstract
AIM: To investigate the effect of Coriolus versicolor polysaccharide B (CVPS-B), a new water-soluble component of polysaccharides from the fungus Coriolus versicolor (Fr) L on monocyte chemoattractant protein-1 (MCP-1) gene expression in rat splenocytes.
METHODS: Expression of MCP-1 mRNA in rat splenocytes was examined by reverse transcription-polymerase chain reaction (RT-PCR) with beta- actin as an internal standard. Sequencing of RT-PCR products was performed to confirm their specificity in MCP-1 gene composition.
RESULTS: (1) Without pre-treatment of lipopolysaccharide (LPS), the relative MCP-1 mRNA expression ratios (MCP-1/beta-actin) for the saline control group and for CVPS-B groups in 3 different doses (10, 20, and 30 mg . kg-1 . d-1, ip, for 4 d) were 1.4 +/- 0.3, 1.6 +/- 0.4, 1.7 +/- 0.5, and 1.5 +/- 0.4, respectively (P > 0.05); (2) LPS (10 microg . kg-1, ip) enhanced the expression of MPC-1 mRNA by the ratio of 114 %; (3) pre-treatment with CVPS-B of 4 different doses (5, 10, 30, and 50 mg . kg-1 . d-1, ip, for 4 d) decreased the LPS induced expression of MPC-1 mRNA by the ratios of 51 %, 70 %, 84 %, and 99 %, respectively (n = 6).
CONCLUSION: In a dose-related fashion, CVPS-B inhibited the expression of MCP-1 mRNA induced by LPS in the rat splenocytes, but did not significantly affect the expression of MPC-1 mRNA in the normal rat.
Horticulture Research International, Wellesbourne, Warwick CV35 9EF, UK. gary.bending@hri.ac.uk
Abstract
The capacity of nine species of white rot fungus from a variety of basidiomycete orders to degrade contrasting mono-aromatic pesticides was investigated. There was no relationship between degradation of the dye Poly R-478, a presumptive test for ligninolytic potential, and degradation of the highly available pesticides diuron, metalaxyl, atrazine or terbuthylazine in liquid culture. However, there were significant positive correlations between the rates of degradation of the different pesticides. Greatest degradation of all the pesticides was achieved by Coriolus versicolor, Hypholoma fasciculare and Stereum hirsutum. After 42 days, maximum degradation of diuron, atrazine and terbuthylazine was above 86%, but for metalaxyl less than 44%. When grown in the organic matrix of an on-farm “biobed” pesticide remediation system, relative degradation rates of the highly available pesticides by C. versicolor, H. fasciculare and S. hirsutum showed some differences to those in liquid culture. While H. fasciculare and C. versicolor were able to degrade about a third of the poorly available compound chlorpyrifos in biobed matrix after 42 days, S. hirsutum, which was the most effective degrader of the available pesticides, showed little capacity to degrade the compound.
Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan. y.iimura@aist.go.jp
Abstract
In efforts aimed at the detoxification of contaminated areas, plants have many advantages over bacteria and fungi. We are attempting to enhance the environmental decontamination functions of plants by transferring relevant genes from microorganisms. When the gene for Mn-peroxidase (MnP) from Coriolus versicolor was expressed in transgenic tobacco plants, one line (designated fMnP21) expressed MnP activity at levels 54-fold higher than in control lines. When undamaged roots of transgenic plants were applied to liquid medium supplemented with 250 microM pentachlorophenol (PCP), the decrease in the level of PCP in fMnP21 (86% reduction) was about 2-fold higher than that in control lines (38% reduction). Expression of the gene for MnP in the transgenic plants had no obvious negative effects on their vegetative and sexual growth. Our system should contribute to the development of novel methods for the removal of hazardous chemicals from contaminated environments using transgenic plants.