Production and Regulation of Extracellular Endocellulase by Agaricus bisporus

Manning, Kenneth C.; Wood, David А.

doi:10.1099/00221287-129-6-1839

Cited by 23 publications

(24 citation statements)

References 24 publications

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“…The abundant cellulose in this medium suggests cellulase may be involved; synthesis of trehalose from the hexose produced by the action of a cellulase could be mediated by trehalose phosphate synthetase, as is found for Dictyostelium discoideum (Killick, 1979). Although the latter enzyme has not been established in A. bisporus, an extracellular endocellulase, which exhibits a coincidence and correlation with flushing similar to that found above for trehalase and glycogen phosphorylase, has been demonstrated (Wood & Goodenough, 1977;Manning & Wood, 1983;N. Claydon, pers.…”

Section: Discussionmentioning

confidence: 97%

VARIATIONS IN ACTIVITIES OF GLYCOGEN PHOSPHORYLASE AND TREHALASE DURING THE PERIODIC FRUITING OF THE EDIBLE MUSHROOM AGARICUS BISPORUS (LANGE) IMBACH.

1987

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SUMMARYActivities of trehalase and glycogen phosphorylase were determined for stage 1 (pin) sporophores of Agaricus bisporus harvested daily throughout several fruiting cycles (flushes). Both enzymes exhibited maximum activity coincident with peak flush, as defined by maximum yield of stage 2 to 4 sporopbores and minimum activity during the interflush periods. Glycogen phosphorylase activity sometimes peaked on more than one occasion during a flush, whereas trehalase gave only a single peak of activity per flush. These results are discussed in relation to metabolic events associated with carbobydrate changes during tbe periodic fruiting cycle of tbis fungus.

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Section: Discussionmentioning

confidence: 97%

VARIATIONS IN ACTIVITIES OF GLYCOGEN PHOSPHORYLASE AND TREHALASE DURING THE PERIODIC FRUITING OF THE EDIBLE MUSHROOM AGARICUS BISPORUS (LANGE) IMBACH.

1987

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“…A. bisporus D649 mycelium was grown in 50 ml of defined minimal medium (Manning & Wood, 1983) with Whatman CC41 microcrystalline cellulose (0.5 g l-'), or with CM-cellulose, D-fructose, D-glucose or glycerol (each 1.0 g 1-l). The transfer experiments were carried out by filtering the culture medium through a nylon mesh under sterile conditions, washing the mycelium with 100 ml minimal medium lacking any carbon source and transferring to a fresh culture medium with the appropriate carbon source.…”

Section: Methodsmentioning

confidence: 99%

“…Cellulase production by A. bisporus is inducible by cellulose and repressed by easily metabolizable carbon sources (Manning & Wood, 1983;Wood et al, 1988). Induced expression of both cell and cel3 in minimal medium occurs at least in part by an increase in transcription of the genes, as measured in nuclear runon assays (Yagiie et al, Chow et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

“…Agaricus bisporus, the edible mushroom, produces a complete cellulase system that enables its growth on crystalline cellulose as the sole carbon source (Manning & Wood, 1983;Wood et al, 1988). We have undertaken the study of cellulase production by A. bisporus from a molecular perspective with the aim of understanding its regulation both in minimal media and during development of the sporophore.…”

Section: Introductionmentioning

confidence: 99%

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Expression of CEL2 and CEL4, Two Proteins from Agaricus Bisporus with Similarity to Fungal Cellobiohydrolase I and -mannanase, Respectively, is Regulated by the Carbon Source

Yagüe

Mehak-Zunic

Morgan³

et al. 1997

Microbiology

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Two new cellulose-growth specific (cel) cDNAs, cel2 and cel4, have been isolated from an Agaricus bisponrs cDNA expression library by immunoscreening with an A. bisporus anti-'endoglucanase antibody. The deduced amino acid sequences showed that both C E U and CEL4 proteins have a modular structure consisting of a fungal-type cellulose-binding domain (CBD) and a catalytic domain separated by a linker region rich in Pro, Ser and Thr. The CELZ and CEDI catalytic domains were homologous to fungal cellobiohydrolases (CBH) in family 7 and to fungal mannanases in family 5 of the glycosyl hydrdases, respectively. A previously isolated cDNA derived from a constitutive gene was also sequenced. The deduced amino acid sequence corresponded to 5-aminolaevulinic acid synthase (ALA), the first enzyme in the haem biosynthetic pathway, and was most similar to other fungal ALAS. RNA analysis showed that the expression of cel2 and cel4 genes was induced by cellulose and repressed by glucose, fructose and lactose. The soluble cellulose derivative CM-cellulose induced mRNA accumulation for cell but not cel2, cel3 or cel4. Mannitol, maltose, sorbitol and glycerol decreased cel2 and cel4 mRNA levels to different extents. cell, cel2, cel3 and cel4 mRNAs all disappeared after the addition of glucose with apparent half-lives of less than 20 min. Whether cel mRNAs have short half-lives or glucose affects the stability of cel transcripts remains to be investigated.

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“…For the laboratory liquid cultures, static cultures of A. bisporus D649 in 2% (wt/vol) malt extract medium (50 ml in 250-ml conical flasks) were inoculated with agar cubes (0.5 by 0.5 by 0.5 cm) cut from malt extract plate cultures to include the colony margin and incubated at 25°C in the dark. After 7 days of growth, the A. bisporus mycelium was homogenized by shaking the samples with sterile glass beads (4-mm diameter); 1-ml amounts were used to inoculate 50 ml (in 250-ml flasks) of Treschow's minimal medium (29) containing 0.5 g of Dfructose per liter (19), and the flasks were incubated at 25°C in the dark. After 14 days of growth, 1 ml of fructose-grown fragmented mycelium inoculant was transferred into 100 ml (in Roux bottles) of either fresh D-fructose medium (0.5 g/liter) or Solka floc BW40 (0.5 g/liter) (International Filler Corporation, North Tonawanda, N.Y.) as the sole carbon source.…”

Section: Methodsmentioning

confidence: 99%

The cel4 Gene of Agaricus bisporus Encodes a β-Mannanase

Tang

Waterman

Smith

et al. 2001

Appl Environ Microbiol

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Mannases have industrial uses in food and pulp industries, and their regulation may influence development of the mushrooms of commercially important basidiomycetes. We expressed an Agaricus bisporus cel4 cDNA, which encodes a mannanase, in Saccharomyces cerevisiae and Pichia pastoris. CEL4 had no detectable activity on cellulose or xylan. This gene is the first isolated from this economically important fungus to encode a mannanase. P. pastoris secreted about three times more CEL4 than S. cerevisiae. The removal of the cellulosebinding domain of CEL4 lowered the secreted specific activity by P. pastoris by approximately 97%. The genomic sequence of cel4 was isolated by screening a cosmid library of A. bisporus C54-carb8. The open reading frame was interrupted by 12 introns. The level of extracellular CEL4 increases dramatically at the postharvest stage in compost extracts of A. bisporus fruiting cultures. In laboratory liquid cultures of A. bisporus, the activity of CEL4 detected in the culture filtrate reached a maximum after 21 days. The levels of CEL4 broadly mirrored the levels of enzyme activity. In the Solka floc-bound mycelium, CEL4 protein showed a maximum after 2 to 3 weeks of culture and then declined. Changes in CEL4 activity during fruiting-body development suggest that hemicellulose utilization plays an important role in sporophore formation. The availability of the cloned gene will further studies of compost decomposition and the extracellular enzymes that fungi deploy in this process.␤-Mannanase enzymes (endo-1,4-␤-D-mannanase, mannan endo-1,4-␤-mannosidase; EC 3.2.1.78) are endohydrolases that catalyze the random hydrolysis of ␤-1,4-mannosidic linkages in the main chain of galactomannan, glucomannan, galactoglucomannan, and mannan (20). These enzymes are of particular interest in ligninolytic fungi, where there is a complex interplay between the processes of degradation of lignin, cellulose, and hemicellulose (including the mannans). There are possible biotechnological applications. ␤-Mannanase can be used to bleach pulp, to reduce the viscosity of instant coffee, and for the clarification of fruit juices and wines (35). At the same time, the role of hemicellulases in wood decay and the breakdown of leaf litter remains poorly understood. The cultivated mushroom Agaricus bisporus, a ligninolytic leaf litter degrader (8), is the source of the mannanase described in this paper.The deduced CEL4 amino acid sequence shows that the encoded protein has a modular structure (40). There is a signal peptide at the N terminus, typical of proteins that are secreted into the medium, a catalytic domain, and a linker rich in serine, proline, and threonine that separates a cellulose-binding domain from the catalytic domain. The catalytic domain of CEL4 had the most amino acid sequence similarity with ascomycete mannanases from Aspergillus aculeatus (5) and Trichoderma reesei (28), which belong to glycosyl hydrolase family 5 (43 and 42%, respectively). Therefore, based on amino acid similarities of the catalytic dom...

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Production and Regulation of Extracellular Endocellulase by Agaricus bisporus

Cited by 23 publications

References 24 publications

VARIATIONS IN ACTIVITIES OF GLYCOGEN PHOSPHORYLASE AND TREHALASE DURING THE PERIODIC FRUITING OF THE EDIBLE MUSHROOM AGARICUS BISPORUS (LANGE) IMBACH.

VARIATIONS IN ACTIVITIES OF GLYCOGEN PHOSPHORYLASE AND TREHALASE DURING THE PERIODIC FRUITING OF THE EDIBLE MUSHROOM AGARICUS BISPORUS (LANGE) IMBACH.

Expression of CEL2 and CEL4, Two Proteins from Agaricus Bisporus with Similarity to Fungal Cellobiohydrolase I and -mannanase, Respectively, is Regulated by the Carbon Source

The cel4 Gene of Agaricus bisporus Encodes a β-Mannanase

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