The Role of Laccase in Carpophore Initiation in Coprinus congregatus

Ross, Ian K.

doi:10.1099/00221287-128-11-2763

Cited by 25 publications

(38 citation statements)

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“…For example, in basidiomycetes, such as Lentinus sp. and Coprinus sp., laccase is produced actively in the developmental stage of primordia (12,19). In Aspergillus nidulans, it is synthesized preferentially when vegetative hyphae begin to differentiate conidiophores, and it mediates formation of the green pigment in conidia (2,11).…”

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Isolation and characterization of a laccase-derepressed mutant of Neurospora crassa

Tamaru

Inoue

1989

J Bacteriol

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Laccase from the ascomycete Neurospora crassa is an inducible secretory enzyme. Production of this enzyme is repressed in vegetative cultures but can be induced by treatment with low concentrations of cycloheximide. Isolation and characterization of a derepressed mutant, the lah-l mutant, that is capable of producing laccase in vegetative cultures without induction by cycloheximide are described. The lah-l mutation is mapped between nit-2 and leu-3 on linkage group I, and it behaved as a recessive mutation in a forced heterokaryon. No differences were detected biochemically or immunologically between the laccase protein produced by the lah-1 mutant in the absence of cycloheximide and that induced with cycloheximide in the wild-type strain. This suggests that both laccases (66 kilodaltons) are products of the same structural gene. Relative amounts of laccase in the culture filtrate of the lah-l mutant were much higher than those induced with cycloheximide in the wild-type strain, demonstrating high efficiency of the lah-l mutant in production and secretion of laccase. The time course of laccase production by the lah-l mutant revealed that expression of 66-kilodalton laccase was repressed in conidia and derepressed during vegetative mycelial growth. This suggests that a multiple regulatory mechanism is involved in the production and/or maturation of Neurospora laccase. The lah-l mutant may be useful for identifying genes that regulate expression of the laccase gene in N. crassa.Laccase is a ubiquitous enzyme in fungi (18). Its activity has been observed intra-and/or extracellularly at various stages of development. For example, in basidiomycetes, such as Lentinus sp. and Coprinus sp., laccase is produced actively in the developmental stage of primordia (12,19). In Aspergillus nidulans, it is synthesized preferentially when vegetative hyphae begin to differentiate conidiophores, and it mediates formation of the green pigment in conidia (2,11). In Podospora anserina, laccase is formed during cell lysis (1). These findings suggest that synthesis of this enzyme is developmentally regulated.Induction of laccase by a variety of substances in various fungi independently of developmental regulation has been reported. Effects of inducers of laccase formation differ from fungus to fungus. In Botrytis sp., laccase is produced only in the presence of inducer, and the characteristics of laccase, such as its molecular weight, amino acid composition, electrophoretic mobility, and heat inactivation, vary depending on the nature of the inducer (16, 17). In Neurospora crassa, production of laccase is induced by addition of low concentrations of protein synthesis inhibitors, such as cycloheximide and puromycin, to the culture medium used for vegetative growth (4). The physical and chemical properties of Neurospora laccase excreted under such induction conditions have been characterized (5, 14). Furthermore, the laccase gene has been cloned and its nucleotide sequence has already been determined (6, 7), providing a basis for molecula...

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confidence: 99%

Isolation and characterization of a laccase-derepressed mutant of Neurospora crassa

Tamaru

Inoue

1989

J Bacteriol

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“…The hyphal tip isozyme, which is a membrane-associated one, is implicated in the development of C. congregatus. The enzyme level is highest in the youngest growth zone and decreases rapidly with age [3]. Pigment formation occurs by the enzyme reaction.…”

Section: Introductionmentioning

confidence: 99%

“…When the whole mycelial mat grown under dark conditions is illuminated, mushroom formation occurs several days later only at the hyphal tip zone where it was illuminated [3,4]. In order for development to occur, the laccase level should be higher than a certain threshold [3,4]. Ross has postulated that the hyphal tip laccase is involved in the initial, light-requiring step [3].…”

Section: Introductionmentioning

confidence: 99%

“…Pigment formation occurs by the enzyme reaction. When the whole mycelial mat grown under dark conditions is illuminated, mushroom formation occurs several days later only at the hyphal tip zone where it was illuminated [3,4]. In order for development to occur, the laccase level should be higher than a certain threshold [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…In order for development to occur, the laccase level should be higher than a certain threshold [3,4]. Ross has postulated that the hyphal tip laccase is involved in the initial, light-requiring step [3].…”

Section: Introductionmentioning

confidence: 99%

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Transformation and laccase mutant isolation in Coprinus congregatus by restriction enzyme-mediated integration

Leem¹

1999

FEMS Microbiology Letters

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Coprinus congregatus did not show any growth on a minimal medium in the presence of phosphinothricin which inhibited glutamine synthetase. Genetic transformation to phosphinothricin resistance in C. congregatus was carried out successfully by restriction enzyme-mediated integration. The procedure was improved to yield 550 transformants per Wg of DNA, and three laccase mutants were generated. The vector pBARGEM 7-1 which had the phosphinothricin resistance gene was detected in the restriction enzyme fragments of chromosomal DNA from the transformants by Southern hybridization. Transformants showed identical electrophoretic banding patterns but CL1430b had a faster moving band when analyzed by native PAGE. z

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Laccases and other polyphenol oxidases in ecto- and ericoid mycorrhizal fungi

2002

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Polyphenol oxidases are known to be produced by a range of ectomycorrhizal (ECM) and ericoid mycorrhizal fungi. These enzymes include laccase (EC 1.10.3.2), catechol oxidase (EC 1.10.3.1) and tyrosinase (EC 1.14.18.1), between which there exists considerable overlap in substrate affinities. In this review we consider the nature and function of these enzymes, along with the difficulties associated with assigning precise enzymatic descriptions. The evidence for production of laccase and other polyphenol oxidases by ECM and ericoid mycorrhizal fungi is critically assessed and their potential significance to the mycorrhizal symbioses discussed.

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The Role of Laccase in Carpophore Initiation in Coprinus congregatus

Cited by 25 publications

References 17 publications

Isolation and characterization of a laccase-derepressed mutant of Neurospora crassa

Isolation and characterization of a laccase-derepressed mutant of Neurospora crassa

Transformation and laccase mutant isolation in Coprinus congregatus by restriction enzyme-mediated integration

Laccases and other polyphenol oxidases in ecto- and ericoid mycorrhizal fungi

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