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PubMed1993

[Two cases of acute eosinophilic pneumonia with precipitating antibody against Trichosporon cutaneum and Trichoderma viride].

Two cases of acute eosinophilic pneumonia are described. The patients presented with an acute febrile illness, dry cough, severe hypoxemia and diffuse pulmonary infiltrates. Total cell count and the number of eosinophils were increased in bronchoalveolar lavage fluid. The TBLB specimen showed eosinophilic infiltration of alveolar walls and spaces. Precipitating antibodies against Trichosporon cutaneum and Trichoderma viride were noted in the patients' sera, and environmental provocation tests gave positive results. The clinical features of acute eosinophilic pneumonia resemble those of summer type hypersensitivity pneumonitis. From these results, we consider that there is a certain degree of overlap between the two diseases.

Adult↗
PubMed1993

Triggering of cellulase biosynthesis by cellulose in Trichoderma reesei. Involvement of a constitutive, sophorose-inducible, glucose-inhibited beta-diglucoside permease.

We prepared [U-14C]cellobiose by cultivating Acetobacter pasteurianus in the presence of [U-14C]glucose and hydrolyzing the [U-14C]cellulose formed with beta-glucosidase-free cellulase from Trichoderma reesei. This 14C-labeled cellobiose was used to investigate the presence of an uptake system for cellobiose in T. reesei. Evidence was obtained for the presence of a high affinity (Km for cellobiose 0.3 microM) but low activity (2.5 milliunits/mg fungal dry weight) cellobiose permease. The permease is formed constitutively, but higher levels are formed after addition of sophorose (glucosyl-beta-1,2-diglucoside), a reputed cellulase inducer. The permease appears to be specific for beta-diglucosides, as the uptake of [U-14C]cellobiose is inhibited by sophorose, gentiobiose (glucosyl-beta-1,3-glucoside), and cellobiose. Under these conditions, cellooligodextrines (n, 4-7; final concentration, 1 mM) are not inhibitors. Glucose, but no other monosaccharides, inhibits the permease. The hypersecretory mutant T. reesei RUT C-30 exhibits elevated permease activities, whereas in T. reesei QM 9979, a mutant strain defective in the induction of cellulases by cellulose or sophorose, strongly reduced permease activities were demonstrated. The results stress a hitherto not recognized point of control in the induction of cellulases by T. reesei at the level of uptake of cellulose oligosaccharides.

Cellulase↗
PubMed1993

Role of the interdomain linker peptide of Trichoderma reesei cellobiohydrolase I in its interaction with crystalline cellulose.

Cellobiohydrolase I (CBH I), the major component of Trichoderma reesei cellulolytic system, is comprised of a catalytic core domain joined to a cellulose binding-domain (CBD) by an extended O-glycosylated interdomain linker peptide. Two internal deletions were introduced to the linker in order to investigate its function particularly in the hydrolysis of crystalline cellulose. Deletion of the first one-third of the linker, including a putative hinge region, reduces the binding capacity of CBH I in high enzyme coverage but does not affect its enzymatic activity on crystalline cellulose. The longer deletion removing practically all of the linker dramatically reduces the rate of crystalline cellulose degradation even though the enzyme still binds to the substrate. We conclude that sufficient spatial separation of the two domains is required for efficient function of CBH I. It is evident that the presence of a functional CBD is increasingly important for CBH I toward higher enzyme to cellulose ratios. Our data suggest that the putative hinge removed by the first deletion facilitates CBD-driven binding and dense packing of the wild type enzyme on the cellulose surface.

Adsorption↗
PubMed1993

Hydrolytic properties of two cellulases of Trichoderma reesei expressed in yeast.

Two cellulases of the filamentous fungus Trichoderma reesei, cellobiohydrolase II (CBHII, EC 3.2.1.91) and endoglucanase I (EGI, EC 3.2.1.4), produced in recombinant strains of the yeast Saccharomyces cerevisiae, were tested in the hydrolysis of cellulose, xylan and other polymeric substrates. Both enzymes were active against unsubstituted, insoluble cellulose. CBHII had greater activity than EGI against crystalline cellulose, whereas in the case of amorphous substrate the order was reversed. Evidence for synergism was obtained when mixtures of the two enzymes were used with a constant total protein dosage. The EGI was also active against soluble substituted cellulose derivatives, whereas the activity of CBHII against these substrates was insignificant. Both enzymes were active against barley (1-->3,1-->4)-beta-glucan, but were inactive against (1-->3,1-->6)-beta-glucan (laminarin). An apparent low mannan-degrading activity of EGI against locust-bean (Ceratonia siliqua) gum galactomannan was not confirmed when homopolymeric mannan was used as substrate in a prolonged hydrolysis test. EGI exhibited considerably greater activity against insoluble, unsubstituted hardwood xylan than against amorphous cellulose. Soluble 4-O-methyl-glucuronoxylan was also attacked by EGI, although to a somewhat lesser extent than the unsubstituted xylan. By comparison with two purified xylanases of T. reesei, EGI produced xylo-oligosaccharides with a longer mean chain length when acting on both substituted and unsubstituted xylan substrates. CBHII was inactive against xylan.

Cellulose↗
PubMed1995

Molecular cloning and expression in S. cerevisiae of two exochitinases from Trichoderma harzianum.

The synthetic exochitinase substrate 4-methylumbelliferyl N-acetylglucosamine was used to identify seven full-length exochitinase-encoding cDNAs from a Trichoderma harzianum cDNA library by expression in yeast. The cDNA clones represented transcripts of two exochitinase genes, designated as exc1 and exc2, which cross-hybridized under moderate stringency conditions in genomic Southern blots. The exc1 cDNA encodes a 578 amino acid polypeptide showing 72% similarity to the exc2-encoded 602-residue polypeptide. The deduced exochitinase amino acid sequences were found to be homologous with mammalian and fungal hexosaminidases as well as a bacterial chitobiosidase. The substrate specificity of the recombinant enzymes expressed in S. cerevisiae indicates that the enzymes are N-acetylglucosaminidases releasing single N-acetylglucosamine residues from the non-reducing end of the chitin substrate.

Amino Acid Sequence↗
PubMed1996

Secretion of Trichoderma reesei beta-glucosidase by Saccharomyces cerevisiae.

An intronless form of the bgl1 gene encoding an extracellular beta-glucosidase from Trichoderma reesei was expressed in the yeast Saccharomyces cerevisiae under the control of the yeast GAL1 promoter. Transformation of a yeast strain with this vector resulted in transformants that produce and secrete active beta-glucosidase into the growth medium. Additionally, active recombinant beta-glucosidase protein was shown to be localized predominantly in the periplasmic space by using a p-nitrophenyl beta-D-glycoside hydrolysis assay against fractionated yeast cells. The apparent size of the recombinant enzyme was 10-15 kDa larger than that of the native form. Treatment of the recombinant beta-glucosidase with endoglycosidase-H indicated the apparent increase in size was due to N-linked glycosylation.

Base Sequence↗
PubMed1995

The 45Ca2+ uptake by Trichoderma viride mycelium. Correlation with growth and conidiation.

The properties of Ca2+ uptake by Trichoderma viride were studied using radionuclide 45Ca2+ in conjunction with the study of effects of agents influencing the Ca2+ homeostasis on the 45Ca2+ uptake, vegetative growth and conidiation. Mycelium of T. viride was found to take up 45Ca2+ in time- and temperature-dependent manner. The 45Ca2+ uptake could be distinguished from the 45Ca2+ binding by the insensitivity to washing with EGTA (ethylene glycol-bis(2-amino ethyl ether)-N,N,N',N'-tetraacetic acid)-containing solution. The 45Ca2+ uptake was only slightly suppressed by the treatment used to de-energize cells. Agents known to influence Ca2+ homeostasis in animal and plant cells were also active in perturbing the Ca2+ homeostasis in T. viride. In this respect, the agents tested had dual (stimulatory or inhibitory) effects on the 45Ca2+ uptake. No clear correlation among the perturbation of the 45Ca2+ uptake and the inhibition of growth and conidiation was found for the group of compounds tested. Sr2+ and Mg2+ inhibited 45Ca2+ uptake but did not inhibit growth and conidiation. Co2+, Cd2+ inhibited both 45Ca2+ uptake and growth. Other agents tested (Cu2+, Ni2+, La3+, dihydropyridines), which inhibited growth of T. viride, induced massive 45Ca2+ uptake by its mycelium. Ba2+ and Mn2+ showed a biphasic effect on 45Ca2+ uptake-inhibition at lower, and stimulation at higher concentrations, but they had only a slight inhibitory effect on the growth or conidiation at higher concentrations. The 45Ca2+ uptake was influenced by addition of monovalent cations to a small extent only. Na+ (up to 75 mmol.l-1), less than K+, slightly suppressed the 45Ca2+ uptake leaving both growth and conidiation unaffected. Upon depriving the fungus of Ca2+ by chelation of extracellular Ca2+ (not Mg2+ or divalent trace metals) by EGTA, which interfered with Ca2+ homeostasis, vegetative growth rate, and starvation-induced conidiation were restricted. These results suggest that the sustained Ca2+ influx occurs across the T. viride plasma membrane which may be a target site for the antifungal action of heavy metal ions, and its perturbation may lead to disturbances in physiological processes including growth and conidiation. The properties of the Ca2+ influx in T. viride observed substantially differ from those observed in animal cells.

Biological Transport↗
PubMed1996

Immunoaffinity chromatographic purification of cellobiohydrolase II mutants from recombinant trichoderma reesei strains devoid of major endoglucanase genes.

Efficient purification of Trichoderma reesei cellobiohydrolase II (CBHII) requires the use of affinity chromatography based on a substrate analogue. Due to altered substrate binding, the purification of many active-site mutants of CBHII from the complex fungal culture media represents a considerable challenge. Here we describe a combination of two approaches to facilitate the purification: the first is based on the construction of novel engineered T. reesei strains devoid of the major contaminating endoglucanases, and the second uses immunoaffinity chromatography as the final purification step. Two different procedures for the preparation of the antibody matrix were tested. Crosslinking of the monoclonal antibody to Protein G matrix instead of the conventional immobilization via cyanogen bromide increased the binding efficiency. Three different active-site mutants of CBHII bound to the immunoaffinity column in neutral pH and were eluted in pH 2.7. The purity of the CBHII mutant preparations was tested using small chromophoric substrates and hydroxyethyl cellulose, which are hydrolyzed by many other cellulases but not by CBHII. The immunoaffinity column purified the CBHII mutants over 800-fold in a single step and resulted in homogeneous protein preparations free of proteolytically cleaved forms of CBHII. The use of the double replacement T. reesei production strains, especially the one lacking the genes coding for both the endogeneous CBHII and the endoglucanase II (EGII), helped to reduce the total endoglucanase activity in the preparations.

Binding Sites↗
PubMed1996

The indoor microfungus Trichoderma viride potentiates histamine release from human bronchoalveolar cells.

Trichoderma viride (Tv) is often found in damp and mouldy buildings where people complain of adverse health effects including mucosal/respiratory symptoms. Inhaled spores can reach the alveoli and may interact with the airway epithelium. An interaction with the mucosal mast cells was studied in cells obtained by bronchoalveolar lavage (BAL) from 18 individuals. The fungal spores were found to trigger histamine release from the BAL cells, but relatively high concentrations (0.1-2 mg/ml) were needed. A similar dose response was obtained in basophil histamine release. The Tv-induced mediator release was caused by non-immunological (non-IgE-dependent) mechanisms since the histamine release was not changed by removal of IgE from the basophils before exposure of the cells to the spores. However, in very low concentrations (0.1 ng/ml) the fungal spores were found to potentiate IgE-mediated histamine release triggered by anti-IgE antibody in suspensions of BAL cells. Potentiation was also obtained in basophil histamine release, but relatively high concentrations of Tv (10(-2) mg/ ml) were needed. Our in vitro experiments show that mucosal mast cells from the airways are highly sensitive to the potentiating effect of Tv. Although inhalation studies are needed to determine the in vivo effect of the spores, the results suggest reinforcement of mediator release to be a mechanism in the adverse health implications observed in mouldy buildings.

Adult↗
PubMedDate not supplied

[Influence of Bacillus intermedius RNAse on growth-stimulating and antagonistic characteristics of Trichoderma harzianum].

Bacillus intermedius RNAase (with specific activity of 1,000,000 units per one mg of protein) at concentration of 1 x 10(-3) mg/ml was shown to increase antagonistic and growth-stimulating properties of Trichoderma harzianum. An application of trichodermin which was treated with an enzyme enhanced cucumber crop capacity by 15-18% in industrial conditions.

Bacillus↗
PubMed1996

Transcriptional control of the cellulase genes in Trichoderma reesei.

The expression of the cellulase transcripts of Trichoderma reesei is controlled by the nature of the energy carbon sources used in the culture medium. Cellulose and the soluble disaccharide sophorose, but not glycerol or glucose, act as inducers. Evidence is presented suggesting that a low constitutive extracellular cellulolytic system catalyzes the formation of a soluble inducer from cellulose, and this inducer triggers the expression of the cellulase transcripts. This basal and cellulose-induced expression of the cellobiohydrolase I mRNAs (cbh1), the major member of the cellulase system, is transcriptionally controlled by two independent cis-acting DNA regions. In addition, expression of the cbh1 transcript is influenced by the physiological state of the mitochondria and this sensitivity is controlled through the 5'-flanking DNA sequence of this gene.

Cellulase↗
PubMed1997

Hybridization dominance of kinetics in recombinant ATH-1376 obtained via protoplast fusion between Aspergillus niger and Trichoderma reesei.

Comparisons of the kinetics of mycelium growth, cellulase biosynthesis, and the degradation of filter paper to accumulate reducing-sugar by the filtrates of cultures were carried out among the recombinant strain ATH-1376 and its two parents, Aspergillus niger AMS11 and Trichoderma reesei QM9414. The results showed that both the specific mycelium growth rate and the cellulase biosynthesis rate of the recombinant were dramatically dominant over those of the two parents. In addition, the negative correlation between the specific mycelium growth rate and the cellulase biosynthesis rate of the recombinant ATH-1376 was much lower than those of its parents. In terms of the amount of reducing-sugar accumulated from the hydrolysis of filter paper by culture filtrates, there were great differences among the three different treatments, i.e., fermentation filtrate of single parental strain, mixture of the fermentation filtrates from two parental strains with different ratios (v:v), and filtrate from the mixed culture of the two parental strains. Out of these, the second approach, particularly with the ratio of 1:1, was best for the accumulation of reducing sugar. Within various tested periods of enzymic hydrolysis, the amounts of reducing-sugar produced by the recombinant were 1.19 to 2.26 times as much as the maximum amounts produced in parallel by the mixture of filtrates (1:1) from separate fermentations of the two parental strains. These results suggested that constructing the engineered strains with hybridization dominance of these two typical genera of far-heredity could be effective to overcome the great deficiencies of routine mixculture, single-strain fermentation, or double fed-batch fermentations.

Aspergillus niger↗
PubMed1998

Functional conformational changes of endo-1,4-xylanase II from Trichoderma reesei: a molecular dynamics study.

Recent crystallographic studies have revealed a range of structural changes in the three-dimensional structure of endo-1,4-xylanase (XYNII) from Trichoderma reesei. The observed conformational changes can be described as snapshots of an open-close movement of the active site of XYNII. These structures were further analyzed in this study. In addition, a total of four 1 ns molecular dynamics (MD) simulations were performed representing different states of the enzyme. A comparison of the global and local changes found in the X-ray structures and the MD runs suggested that the simulations reproduced a similar kind of active site opening and closing as predicted by the crystal structures. The open-close movement was characterized by the use of distance difference matrixes and the Hinge-find program (Wriggers and Schulten, Proteins 29:1-14, 1997) to be a 'hinge-bending' motion involving two large rigidly-moving regions and an extended hinge. This conformational feature is probably inherent to this molecular architecture and probably plays a role in the function of XYNII.

Binding Sites↗
PubMedDate not supplied

[Biogenesis of cellulolytic enzymes by Trichoderma ligorum on media with "inductor"].

Identical distribution of C2- and Cx-cellulase activities of enzyme complexes produced by Trichoderma lignorum on a medium with lactose, a soluble "inductor", and on a medium with cellulose was found by means of disc elestrophoresis in polyacrylamide gel. The maximum rate of synthesis of cellulases on the medium with lactose was registered during the highest deceleration, and even complete cessation, of the fungal growth. During this phase, only one electrophoretically homogeneous cellulase component with Rf of 0.44 possessing all types of the cellulase activity is present in the cultural broth. In the course of growth of the fungus on cellulose after 48 hours, also only one electrophoretically homogeneous component with Rf of 0.44 was found in the cultural broth when the rate of the substrate degradation was highest. The appearance of minor protein components with the activity of cellulase at later stages of cultivation after cessation of the fungal growth is supposed to be caused by modification of the main cellulase component with Rf of 0.44 by the growth medium.

Cellulase↗
PubMed1999

Mechanisms of coal solubilization by the deuteromycetes Trichoderma atroviride and Fusarium oxysporum

Three different mechanisms can be envisaged that are used by fungi to solubilize coal: the production of alkaline substances, the extrusion of chelators and, of special interest in the scope of biotechnology, the action of enzymes. Whether these mechanisms are operating separately or in various combinations has not yet been finally assessed. The two deuteromycetes Fusarium oxysporum and Trichoderma atroviride solubilize coal by synergistic effects of various differnt mechanisms depending on the cell metabolism. F. oxysporum seems to solubilize coal by increasing the pH of the mycelial surroundings and by the action of chelators induced during growth in glutamate-containing media (without involvement of enzymes). T. atroviride, on the other hand, appears to use, in addition to an alkaline pH and a high chelator activity, at least two classes of enzyme activity to attack coal: hydrolytic activity for coal solubilization and ligninolytic activity for degradation of humic acids.

Journal Article↗
PubMed2001

Differential expression of the Trichoderma reesei beta-xylanase II (xyn2) gene in the xylose-fermenting yeast Pichia stipitis.

The transcriptional control of two native promoters and one heterologous promoter and the production of a heterologous protein from these promoters were evaluated in the xylose-fermenting yeast Pichia stipitis cultivated on xylose and glucose as carbon sources, using the beta-xylanase II xyn2 gene of Trichoderma reesei. The xyn2 gene open reading frame was fused to the P. stipitis xylose reductase gene (XYL1) promoter, the P. stipitis transketolase gene (TKL) promoter and the Saccharomyces cerevisiae phosphoglycerate kinase gene (PGKI) promoter DNA sequences on episomal plasmids. The plasmids were transformed into Pichia stipitis and gene expression and beta-xylanase production monitored. The XYL1 promoter was shown to be inducible in the presence of xylose, as xyn2 transcription and beta-xylanase activity could be measured when the recombinant strain was cultivated on xylose but not when it was cultivated on glucose. TKL promoter expression was found to be constitutive when either glucose or xylose was used as sole carbon source. The PGK1 promoter did not promote xyn2 transcription in P. stipitis. The molecular size of the recombinant Xyn2 protein produced by P. stipitis was 20.7 kDa, which is similar to that of the native T. reesei Xyn2 protein. This indicates no or minimal glycosylation of the recombinant protein. The recombinant xyn2-expressing strain also yielded twice the amount of biomass yielded by the control strain when cultivated in medium containing 1% birchwood xylan as sole carbon source.

Aldehyde Reductase↗
PubMed2005

ooc1, a unique gene expressed only during growth of Hypocrea jecorina (anamorph: Trichoderma reesei) on cellulose.

To grow on cellulose as a carbon source, Hypocrea jecorina (Trichoderma reesei) expresses and secretes a number of cellulases. This mechanism of induction by an insoluble carbon source has been controversially explained, but is most frequently attributed to the formation of the beta-1,2-diglucoside sophorose, a powerful soluble inducer of cellulases, by means of transglycosylation by constitutive or conidia-bound beta-glycoside hydrolases. Some recent results, however, have put the role of sophorose as the mediator of cellulose induction in question. Here we used the rapid subtraction hybridization approach to clone genes expressed by H. jecorina in the presence of cellulose but not upon incubation with sophorose. From a total of 96 expressed sequence tag (EST) fragments, 37 putative positives--representing ten different genes--were selected and analysed. All of them were present in the genome sequence of H. jecorina. Three of them encode proteins known from H. jecorina, five encode enzymes involved in secondary metabolism and one gene encodes an as yet unknown member of glycoside hydrolase family 30. Two EST fragments had no orthologues in other fungi. One of them made up for 25 of the 37 EST fragments analysed. The corresponding gene (only expressed on cellulose, ooc1) encodes a small secreted 10.5-kDa protein. The ooc1 transcript is only detectable during growth on cellulose in darkness, but not on cellulose in light or in the presence of other cellulase inducers (sophorose, lactose), nor is it formed during growth on glucose or glycerol. Its expression is strongly reduced, but not completely abolished in the cellulase non-inducible mutant QM 9978. The results of this study provide evidence that induction of gene expression by cellulose does not necessarily correlate with that by sophorose.

Cellulases↗