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Showing papers on "Trichoderma longibrachiatum published in 1991"


Journal ArticleDOI
TL;DR: The nematotoxic activity, efficient against plant-parasitic species, found in the culture filtrates of two Hyphomycetes: Paecilomyces lilacinus (nematophagous fungus) and Trichoderma longibrachiatum was characterized and selective permeability of different cuticle zones of nematodes for non-charged substances (non-polar) was confirmed.
Abstract: The nematotoxic activity, efficient against plant-parasitic species, found in the culture filtrates of two Hyphomycetes: Paecilomyces lilacinus (nematophagous fungus) and Trichoderma longibrachiatum was characterized. Purification was performed by distillation and liquid chromatography and identification by gas-chromatography coupled with a DCI system (dynamic headspace). The active substance has been identified as acetic acid which, produced abundantly during fungal growth in liquid medium (up to 0.044 mols of CH 3 COOH per culture filtrate litre), inhibited movement of infesting juvenile nematodes. These results were confirmed by comparative studies using the commercial molecule as for the 1 H NMR as the biological tests. The toxic activity appeared only when the carboxylic function was in its undissociated form, hence the real interest of pH when studying this nematicidal activity. A study of the literature confirmed the selective permeability of different cuticle zones of nematodes for non-charged substances (non-polar).

76 citations


Journal ArticleDOI
TL;DR: Two nonadecapeptides, tricholongins BI and BII, which display antifungal and antibacterial activities, have been isolated from in vitro cultures of the fungus Trichoderma longibrachiatum and the results suggest that the N-terminus contains mixed alpha/3(10) bonds.
Abstract: Two nonadecapeptides, tricholongins BI and BII, which display antifungal and antibacterial activities, have been isolated from in vitro cultures of the fungus Trichoderma longibrachiatum. The peptides were separated by reversed-phase HPLC; their amino acid compositions were determined by gas chromatography and their sequences by positive-ion fast-atom-bombardment mass spectrometry and high-field NMR. These linear peptides, containing mainly hydrophobic L-amino acids, 8-9 2-aminoisobutyric acid residues and exhibiting an acetylated N-terminal residue and an amino alcohol C-terminal leucinol belong to the peptaibol class. The methanol solution structure of tricholongins BI and BII has been investigated using both one- and two-dimensional NMR techniques. The total 1H-NMR and 13C-NMR assignments are given. By a combination of the 3JNH,C alpha H coupling constant values, temperature coefficients of the NH and CO groups, amide hydrogen/deuterium-exchange rate measurements and NOE data, a secondary structure for tricholongins in solution has been proposed. Both peptides adopt a similar alpha-helical conformation with a hinge around Pro13 resulting from two 3(10) bonds. The results suggest that the N-terminus contains mixed alpha/3(10) bonds. The membrane permeability modifications induced by tricholongins have been assayed by the use of liposomes composed of egg phosphatidylcholine with 20-30% cholesterol. The peptide-induced leakage of an entrapped fluorescent probe has been followed by fluorescence spectroscopy. In a concentration range of 0.13-0.31 microM, tricholongins induce the leakage of 50% of the entrapped material in 20 min.

67 citations


Journal ArticleDOI
TL;DR: Strong synergistic action is induced by the enzymes acting in concert with cellobiohydrolases (CBHI and CBHII) from the same organism, indicating a highly effective enzymatic system for cellulose degradation.

54 citations


Journal ArticleDOI
TL;DR: Two endoxylanases were purified from the culture medium of Trichoderma longibrachiatum and xylotriose inhibited hydrolysis of xylopentanose by both enzymes, while xylobiose appeared to inhibit xylan enzyme B, but not xylanase A.
Abstract: Two endoxylanases were purified from the culture medium of Trichoderma longibrachiatum. Both enzymes were highly basic, and lacked activity on carboxymethyl-cellulose. An enzyme of 21.5 kDa (xylanase A) had a specific activity of 510 U/mg protein, a Km of 0.15 mg soluble xylan/ml, possessed transglycosidase activity and generated xylobiose and xylotriose as the major endproducts from xylan or xylose oligomers. A larger enzyme of 33 kDa (xylanase B) had a specific activity of 131 U/mg protein, a Km of 0.19 mg soluble xylan/ml, lacked detectable transglycosidase activity and generated xylobiose and xylose as major endproducts from xylan and xylose oligomers. Xylotriose was the smallest oligomer attacked by both enzymes. In addition, xylotriose inhibited hydrolysis of xylopentanose by both enzymes, while xylobiose appeared to inhibit xylanase B, but not xylanase A.

40 citations


Journal ArticleDOI
TL;DR: Using 4-methylumbelliferyl (MUF) beta-D-cellobioside as a substrate, the ability of cellobiohydrolase I from Trichoderma longibrachiatum to catalyze transglycosylation has been demonstrated and a formation of MUF-trisaccharide was observed.

17 citations