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  • 1
    ISSN: 1432-1890
    Keywords: Key words Ectomycorrhiza ; Boletus ; Amanita ; Lactarius ; Russula ; Picea abies ; RAPD ; Intra- and infraspecific variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The application of random amplified polymorphic DNA (RAPD) analysis for the identifcation of ectomycorrhizal symbionts of spruce (Picea abies) belonging to the genera Boletus, Amanita and Lactarius at and below the species level was investigated. Using both fingerprinting [M13, (GTG)5, (GACA)4] as well as random oligonucleotide primers (V1 and V5), a high degree of variability of amplified DNA fragments (band-sharing index 65–80%) was detected between different strains of the same species, hence enabling the identification of individual strains within the same species. The band-sharing index between different species of the same genus (Boletus, Russula and Amanita) was in the range of 20–30%, and similar values were obtained when strains from different taxa were compared. Thus RAPD is too sensitive at this level of relatonship and cannot be used to align an unknown symbiont to a given taxon. We therefore conclude that RAPD is a promising tool for the identification of individual strains, and could thus be used to distinguish indigenous and introduced mycorrhizal strains from the same species in natural ecosystems.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 144 (1986), S. 41-47 
    ISSN: 1432-072X
    Keywords: Trichoderma reesei ; Cellulase ; Choline ; Exoprotein secretion ; Phospholipids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A correlation between intracellular phospholipid levels and the rate of exoprotein synthesis was investigated in the filamentous fungus Trichoderma reesei QM 9414 during growth on cellulose. When the incubation temperature was varied between 20 and 37°C, the exoprotein synthesis rate correlated with the total cellular amount of phospholipids, but not with an individual phospholipid component. In contrast, when phospholipid bases were added exogenuously, a significant stimulation of exoprotein synthesis was observed with choline. The addition of the surfactant Tween 80—which also stimulates exoprotein secretion in T. reesei QM 9414—prevented choline stimulation. Optimal stimulation occurred around 20 mM choline. Choline stimulated exoprotein synthesis in general as shown by increased activities of several extracellular enzymes. Mycelia required preincubation for at least 20 h before stimulation of choline could be seen. Mycelia pregrown in the absence or presence of choline were equally effective in formation of β-glucosidase upon induction with methyl-β-d-glucoside, and the addition of choline to the induction medium had no effect. Choline did not alter the osmotic stability of protoplasts of T. reesei. Electron microscopic examinations and analysis of chemical constituents as well as marker enzymes from choline grown and non-choline grown mycelia revealed higher contents of mitochondria and endoplasmic reticula in choline grown mycelia. The possibility is discussed that choline may stimulate exoprotein synthesis by increasing the cellular content of endoplasmic reticula.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 151 (1989), S. 326-330 
    ISSN: 1432-072X
    Keywords: Trichoderma reesei ; Cellulase induction ; Cellobiono-1,5-lacton ; Sophorose ; Cellobiohydrolase ; Endoglucanase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Induction of synthesis of cellulolytic enzymes in Trichoderma reesei QM 9414 by cellobiono-1,5-lactone (CBL) has been investigated in a replacement system lacking additional carbon source. CBL induced cellulase secretion optimally at pH 5 and a concentration of 70 μg/ml. Higher concentrations lead to lower induction. De novo induction of cellulases was proven by the inhibitory effect of cycloheximide addition. Induction by CBL was shown to act synergistically on induction by sophorose, as it decreased the concentration of sophorose required for maximal induction. Maximal endo-β-1,4-glucanase activities induced by either sophorose or CBL were comparable. The CBL-induced cellulase system contained all the major cellulolytic enzymes of T. reesei, i.e. cellobiohydrolase I and II, and endoglucanase I, as shown by SDS-PAGE, Western blotting and detection with specific mono- and polyclonal antibodies. No differences were seen in the types of individual enzymes formed upon induction by either sophorose or CBL. No other hydrolytic enzymes appear to be induced by CBL (i.e. amylase, laminarinase, xylanase).
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-072X
    Keywords: Morphology ; Manganese deficiency ; Cell wall ; Aspergillus niger ; Citric acid fermentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Morphology and cell wall composition of Aspergillus niger were studied under conditions of manganese sufficient or deficient cultivation in an otherwise citric acid producing medium. Omission of Mn2+ (less than 10-7 M) from the nutrient medium of Aspergillus niger results in abnormal morphological development which is characterized by increased spore swelling, and squat, bulbeous hyphae. Fractionation and analysis of manganese deficient cell walls revealed increased chitin and reduced β-glucan contents as well as reduction of galactose containing polymers, as compared to cell walls from manganese sufficient grown hyphae. Addition of copper induced the same effect as manganese deficiency, both on morphology and cell wall composition. Addition of cycloheximide also produced a very similar type of morphology with increased chitin and reduced β-glucan contents of the cell wall but its effect on galactose was less pronounced.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 132 (1982), S. 349-354 
    ISSN: 1432-072X
    Keywords: Trichoderma ; β-Glucosidase ; Cell walls ; β-1.3-Glucanase ; Cellulolytic enzymes ; Cell wall lytic enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The formation and excretion of β-glucosidase from Trichoderma pseudokoningii was studied during growth on different carbon sources. The enzyme was present under all conditions examined, but increased activity was found during growth on carbon sources favouring slow growth. Two different patterns of β-glucosidase excretion were observed: on carbon sources allowing fast growth a relatively high percentage of total activity was found in the culture fluid, which decreases as the culture grows older, but which increases again during the phase of cell lysis; on carbon sources favouring slow growth, excretion is initially low, but commences at later culture stages. Changes in cell wall composition and cell wall lytic enzyme activities associated with the cell walls were examined during phases of high and low ratios of extracellular to cell-wall bound β-glucosidase activities. With no component of the cell wall (chitin, α-glucan, β-glucan, galactosamine) could correlation with β-glucosidase excretion be identified. Among a number of cell-wall lytic, cell-wall associated enzymes (α-glucanases, β-glucanases, glucosaminidase, galactosaminidase), β-1.3-glucanase activity correlated well with the excretion of β-glucosidase. The results suggest a possible role of β-1.3-glucanases in the mechanism of release of β-glucosidase from cell walls of T. pseudokoningii; this is discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 147 (1987), S. 88-91 
    ISSN: 1432-072X
    Keywords: Aspergillus niger ; ATP:citrate lyase ; Citric acid accumulation ; Lipid biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract ATP:citrate lyase (EC 4.1.3.8) has been identified in cell-free extracts from the filamentous fungus Aspergillus niger. The enzyme was located in the cytosol. It exhibits an activity at least ten times that of acetate-CoA-kinase (EC 6.2.1.1) during growth on carbohydrates as carbon sources, and is thus considered responsible for acetyl-CoA formation under these conditions. It is formed constitutively and its biosynthesis does not appear to be controlled by changes in the nitrogen or carbon source or type. ATP:citrate-lyase appears to be very labile during conventional purification procedures; a method involving fast protein liquid anion exchange chromatography was thus developed in order to obtain enzyme preparations sufficiently free of enzymes which could interfere with kinetic investigations. This preparation displays commonly known characteristics of ATP:citrate lyase with respect to substrate affinities and cofactor requirements, with the exception that the affinity for citrate is rather low (2.5 mM). No activator was found. The enzyme is inhibited by nucleoside diphosphates, nucleoside monophosphates and palmitoyl-CoA. Regulation of ATP:citrate lyase be the energy charge of the cytosol in relation to lipid or citric acid accumulation is discussed in view of these findings.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 123 (1979), S. 73-79 
    ISSN: 1432-072X
    Keywords: Amino acids ; Aspergillus niger ; Manganese deficiency ; Citric acid accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Free amino acid pools have been investigated in a citric acid accumulating strain of Aspergillus niger during batch growth under manganese sufficient and deficient conditions by means of an improved chromatographic method. Studies on the mycelial content of several nitrogenous compounds under manganese sufficient and deficient conditions showed that manganese deficiency resulted in lower amino acid pool sizes during trophophase and considerable accumulation during idiophase, and in a reduction of the protein and nucleic acid contents. Addition of cycloheximide to mycelia grown with sufficient manganese also caused an elevation of free amino acid pool sizes, thus indicating that impairment of protein synthesis by manganese deficiency is responsible for the observed rise in amino acid concentration. Furthermore it was observed that the manganese deficient mycelia excreted high amounts of all amino acids suggesting that manganese deficiency may also affect membrane permeability.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 141 (1985), S. 266-268 
    ISSN: 1432-072X
    Keywords: Manganese deficiency ; Aspergillus niger ; Citric acid accumulation ; Protein degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of manganese deficiency on macromolecule synthesis has been studied in a citric acid producing strain of Aspergillus niger: pulse labelling experiments showed that the synthesis of both protein and RNA was not influenced by the presence of manganese; however, increased protein degradation occurred under manganese deficiency. This was also reflected by the increased activity of an intracellular proteinase activity under these conditions. In replacement cultures addition of inhibitors of RNA, DNA or protein synthesis revealed that only emetine and cycloheximide (which both act at the ribosome) successfully antagonized the adverse effect of manganese ions on citric acid accumulation. Manganese deficiency was also characterized by a decreased portion of polysomes and 80 S ribosomes.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-072X
    Keywords: Trichoderma reesei ; Xylanase ; Ultrastructural localization ; Immunogold labelling ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intracellular location of the “low-molecular weight, alkaline” xylanase (XYN II) of Trichoderma reesei RUT C-30 was investigated during growth on xylan, using immunoelectron microscopy. A monoclonal antibody, produced against XYN II, was used for this purpose. The enzyme was found at the endoplasmic reticulum and in electron dense 0.2 to 0.8 μm vesicles, as well as in the vacuole, at the plasma membrane and in the fungal cell-wall. No staining occured in the cytoplasm, the mitochondria and the nucleus. No Golgi-like structures could be seen. Addition of the carboxylic ionophore monensin blocked xylanase as well as total protein secretion. The results are discussed with respect to XYN II being secreted by T. reesei via a pathway involving the endoplasmic reticulum and secretory vesicles and/or the vacuole.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Addition of soybean oil to Acremonium chrysogenum cultures growing on sugars doubled the specific production of cephalosporin C during the idiophase of growth. While the addition of soybean oil had no effect on the total rate of respiration, the respiration that proceeded via the alternative, cyanide-insensitive pathway exhibited a more than twofold increase. Addition of soybean oil also stimulated the formation of isocitrate lyase activities. Inhibition of oxidative metabolism of one of the products of isocitrate lyase (succinate) by thenoyltrifluoroacetone completely inhibited the alternative respiratory pathway. The role of soybean-oil-stimulated alternative respiration in the stimulation of cephalosporin C production and the role of isocitrate lyase are discussed.
    Type of Medium: Electronic Resource
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