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  • 1
    ISSN: 1432-0983
    Keywords: Trichoderma reesei ; Cellobiohydrolase genes ; Cellulase formation ; Trichoderma sp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eight different species of Trichoderma (T. virgatum, T. longibrachiatum, T. harzianum, T. pseudokoningii, T. polysporum, T. koningii, T. todica, T. saturnisporum), and three strains of T. reesei [QM 6a (wildtype), QM 9123 and QM 9414 (derived mutants)] were found to contain single copies of the cellobiohydrolase genes cbh1 and cbh2 in their genome. This was demonstrated by hybridization of the respective chromosomal DNAs with the corresponding gene fragments of T. reesei QM 9414. According to the relative position of cbh1 and cbh2 in Southern blots, T. harzianum, T. virgatum and T. saturnisporum were clearly distinguishable as unique species. Despite the presence of both cbh genes, these species did not form detectable cellobiohydrolase (CBH) I or II, or exhibit any cellulase activity. All other taxa were identical with respect to the genomic position of cbh1, formed two groups with respect to the position of cbh2, and produced varying amounts of CBH I and II. In all cases CBH I and II production correlated with the relative amount of cbh1- and cbh2-mRNA found. This was particularly true for the three strains of T. reesei, which secreted different amounts of CBH I and II, their efficiency to transcribe cbh1 and cbh2 having been increased as a result of mutation for higher cellulase production.
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  • 2
    ISSN: 1432-072X
    Keywords: Trichoderma reesei ; β-Glucosidase ; Polyheteroglycan ; Cell wall ; Enzyme activation ; Reassociation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The extracellular β-glucosidase from the filamentous fungus Trichoderma reesei QM 9414 is mainly bound to the cell wall of the fungus and only partially released into the medium. Isolation of the cell walls and its hydrolysis by enzymatic treatment with Aspergillus niger cellulase released β-glucosidase, which appeared tightly associated with a cell wall polysaccharide. This polysaccharide was purified by gel filtration and ion exchange chromatography and was shown to consist of mannose, galactose, glucose, galacturonic acid and glucuronic acid. It was devoid of protein and phosphate. It reassociated both with extracellular β-glucosidase as well as β-glucosidase released from the fungus' cell wall. Addition of the polysaccharide to the β-glucosidase in vitro increased the enzyme's activity against 4-nitrophenyl-β-glucoside twofold. These findings suggest, that the isolated polysaccharide functions as an “anchor glycan” for the β-glucosidase in Trichoderma reesei.
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  • 3
    ISSN: 1432-072X
    Keywords: Trichoderma reesei ; Cellobiohydrolase ; Monoclonal antibodies ; Conidial bound enzymes ; Recombinant fungal cellulase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Monoclonal antibodies have been used to determine the presence of cellobiohydrolases I and II (CBH I and II), and endoglucanase I (EG I) on the surface of conidia from Trichoderma reesei QM 9414 and RUT C-30, and 8 other Trichoderma species. For this purpose, proteins were released from the conidial surface by treatment with a non-ionic detergent (Triton X-100 and β-octylglucoside), followed by SDS-PAGE/Western blotting and immunostaining. Both CBH I and II were clearly present, but — unlike in extracellular culture fluids from Trichoderma — CBH II was the predominant cellulase. In T. reesei EG I could not be detected. The higher producer strain T. reesei RUT C-30 exhibited a higher conidial level of CBH II than T. reesei QM 9414. In order to assess the importance of the conidial CBH II level for cellulase induction by cellulose, multiple copies of the chb2 gene were introduced into the T. reesei genome by cotransformation using PyrG as a marker. Stable multicopy transformants secreted the 2- to 4-fold level of CBH II into the culture medium when grown on lactose as a carbon source, but their CBH I secretion was unaltered. Upon growth on cellulose, both CBH I and CBH II secretion was enhanced. Those strain showing highest cellulase activity on cellulose also appeared to contain the highest level of conidial bound CBH II. CBH II was also the predominant conidial cellulase in various other Trichoderma sp. However, roughly the same amount of conidial bound CBH II was detected in all strains, although their cellulase production differed considerably.
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  • 4
    ISSN: 1432-072X
    Keywords: Key words Heteroglycan ; Cell walls ; 1 ; 6-α-d-Mannan ; Trichoderma ; Aspergillus ; β-Glucosidase ; Glycosidases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A heteroglycan responsible for the binding of the enzyme β-1,4-d-glucosidase (EC 3.2.1.21) to fungal cell walls was isolated from cell walls of the filamentous fungus Trichoderma reesei. The heteroglycan, composed of mannose, galactose, glucose, and glucuronic acid, also activated β-1,4-d-glucosidase, β-1,4-d-xylosidase and N-acetyl-β-1,4-d-glucosaminidase activity in vitro. The structural backbone of this heteroglycan was prepared by acid hydrolysis and gel filtration. The molecular structure of the core of the heteroglycan was determined by NMR studies as a linear α-1,6-d-mannan. The mannan core obtained by acid degradation stimulated the β-glucosidase activity by 90%. Several glycosidases from Aspergillus niger were also activated by the T. reesei heteroglycan. The β-glucosidase of Trichoderma was activated by mannan from Saccharomyces cerevisiae to a comparable extent.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 50 (1988), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) followed by immunoblotting was employed to detect intracellular precursors of endo-β-1,4-glucanases (EGs) in Trichoderma reesei QM9414 under conditions of de novo induction by sophorose and de novo carbon catabolite derepression by lactose. Secretion of EGs was always preceded by intracellular accumulation of lower Mr precursors, which became processed to larger Mr forms immediately prior to their extracellular appearance. Treatment of the larger Mr forms with α-mannosidase converted them to forms with the same Mr as the smaller forms, whereas Endo H treatment was without effect. These results are consistent with a requirement of O-linked glycosylation for secretion of EGs by T. reesei.
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  • 6
    ISSN: 1546-1696
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: [Auszug] As a first step to exploit the potential of Trichoderma reesei to produce hemicellulases, we have purified two endo-β-1,4-xylanases (1,4-β-D-xylan xylanohydrolase, EC 3.2.1.8) and cloned their genes. The enzymes were isolated from culture filtrates of T. reesei C 30 grown on xylan as a ...
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Antonie van Leeuwenhoek 67 (1995), S. 363-370 
    ISSN: 1572-9699
    Keywords: riboprinting ; ribotyping ; RFLP ; 18SrDNA ; 25SrDNA ; ITS1 ; ITS2 ; Saccharomyces ; yeast phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Type strains of 10 genotypically distinctSaccharomyces species are differentiated by ribosomal DNA restriction fragment analysis (ribotyping). The full length of the chromosomal ribosomal repeat was amplified in two parts, the 18SrDNA including both ITS regions (2600 bp) and the 25SrDNA (3300 bp). Restriction fragments generated by 9 enzymes from these two products yield characteristic patterns, by which unknownSaccharomyces isolates are assigned to the type strains. For convenient separation and detection only fragments longer than 200 bp were monitored. In contrast to molecular differentiation methods of highest resolution as RAPD-PCR or fingerprinting, the results from ribotyping are absolutely reproducible and thereby suitable for databases. The phylogeny computed from the discrete character matrix for presence/absence of fragments by the PHYLIP program package is in complete accordance to the phylogeny derived from ribosomal RNA sequence analysis. By this the field of application of the long range ribotyping can be regarded basically as equal to DNA sequence analysis of the same locus. Because distant relationships are recognized, missidentified genera were detected upon the species assignment. This cannot be done by methods of higher resolution like RAPD-PCR or fingerprinting.
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