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1.
Two molecular forms of extracellular laccase induced by different phenolics were studied in Botrytis cinerea. The enzyme induced by grapejuice had a MW of 38 000 and contained 80 % sugar while that induced by gallic acid had a MW of 36 000 and contained 70 % sugar. Both forms contained arabinose, xylose, mannose, galactose and glucose but differed markedly in the relative content of these sugars. Tunicamycin, which inhibits glycosylation of peptide chains, considerably reduced the level of laccase in both hyphae and medium. The two enzyme forms differed also in their isoelectric focusing pattern and amino acid composition, the grape juice enzyme being richer in basic amino acids and poorer in acidic ones. A third form, induced by p-coumaric acid, resembled the laccase induced by gallic acid in many of its properties but was apparently not identical to it. The possible significance of the various forms in relation to the infection process by the fungus is discussed. 相似文献
2.
Marc Dubernet Pascal Ribereau-Gayon Henri R. Lerner Eitan Harel Alfred M. Mayer 《Phytochemistry》1977,16(2):191-193
The partial purification of an extracellular laccase from Botrytis cinerea is described. Specificity of the enzyme, its Km for a number of substrates and sensitivity to some inhibitors are described. The enzyme is a typical laccase but has an exceptionally low pI and great stability to acid pH. On gel electrophoresis two isoenzymes could be detected. 相似文献
3.
Both the composition of the culture medium and the nature of the phenolic inducer determine the amount, the rate of formation and the molecular properties of extracellular laccase formed by Botrytis cinerea. Coumaric acid is shown to act as inducer in addition to gallic acid and grape juice. It is suggested that the fungus adapts to different environments by excreting different laccases. These laccases differ in pK, heat stability and substrate specificity but not in Km values to quinol and oxygen. 相似文献
4.
Pectin acts as a second inducer of extracellular laccase formation by Botrytis cinerea, in the presence of a phenolic substance as a first inducer, but pectin alone fails to induce enzyme formation. The possible advantages of this mechanism for the fungus during the process of infection and overcoming host resistance are discussed. 相似文献
5.
The properties of laccase isolated from Schinus molle, including its MW, amino acid and carbohydrate composition, are described. The enzyme is distinct from Rhus laccase both in Km and in carbohydrate composition. 相似文献
6.
Optimal conditions for laccase excretion by Botrytis cinerea were determined. Addition of gallic acid to the culture medium induced maximal enzyme production and excretion. Other inducers previously reported for other organisms were ineffective. The relationships between internal and external laccase formation were determined. 相似文献
7.
Gabriela SansoneIrma Rezza Gastón FernándezViviana Calvente Delia BenuzziMaria Isabel Sanz 《International biodeterioration & biodegradation》2011,65(1):243-247
EDTA, calcium chloride, and two siderophores (rhodotorulic acid produced by Rhodotorula glutinis BNM 0524, and enterochelin from the bacterium Rahnella aquatilis BNM 0523) were evaluated as possible inhibitors of polygalacturonase (PG) and laccase (LC) from Botrytis cinerea. The aim was to apply them to the control of this pathogen, taking into account the fact that these enzymes are related to the invasion and installation of the fungus in the host. Two B. cinerea Pers.:Fr strains (BNM 0527 and BNM 0528) were used. Enzyme activities were measured in the supernatant of 7-day-old cultures. EDTA, calcium chloride, rhodotorulic acid, or enterochelin were added in the reaction mixture. Laccase activity from two strains was more affected by enterochelin (70-80% inhibition) than by the other compounds, while polygalacturonase was more inhibited (45% inhibition) by calcium chloride. The inhibitors were added to the growth medium and after 7 days of culture, the activities of the enzymes were measured in the supernatants. The production of PG and LC in both strains was lower when enterochelin or calcium chloride was added. In the third step, when the inhibitors were tested on apple, all them provided both effects, preventive and curative, against infections caused by B. cinerea, with EDTA and rhodotorulic acid exhibiting more preventive effects while calcium chloride and enterochelin provided more control of pre-existing infections (curative effect), coinciding with their ability to inhibit the production of polygalacturonase and laccase. 相似文献
8.
The phytoalexin wyerone was induced to accumulate in cotyledons of Vicia faba infected with Botrytis cinerea or B. fabae. The acetylenic keto ester, wyerone, was converted to the less antifungal corresponding hydroxy ester, wyerol, by both species of Botrytis in vitro. 相似文献
9.
漆酶是一种含铜的多酚氧化酶,与植物病原菌致病性、黑色素合成及降解木质素等方面相关。为明确漆酶在新月旋孢腔菌的催化作用及其催化活性,以2,2′-连氮-双(3-乙基苯并噻唑-6-磺酸)(简称ABTS)为底物,利用分光光度计在420nm下测定胞内漆酶活力,结果表明酶活测定最佳反应条件为缓冲液pH2.8、Cu2+浓度500μmol/L和0.6mmol/L ABTS。根据漆酶Cu2+结合保守结构域设计了1条引物,对新月旋孢腔菌漆酶基因进行克隆,并通过RACE技术克隆了其全长cDNA序列。开放阅读框长1,803bp, 相似文献
10.
Antifungal activities of zinc oxide nanoparticles (ZnO NPs) and their mode of action against two postharvest pathogenic fungi (Botrytis cinerea and Penicillium expansum) were investigated in this study. ZnO NPs with sizes of 70 ± 15 nm and concentrations of 0, 3, 6 and 12 mmol l−1 were used. Traditional microbiological plating, scanning electron microscopy (SEM), and Raman spectroscopy were used to study antifungal activities of ZnO NPs and to characterize the changes in morphology and cellular compositions of fungal hyphae treated with ZnO NPs. Results show that ZnO NPs at concentrations greater than 3 mmol l−1 can significantly inhibit the growth of B. cinerea and P. expansum. P. expansum was more sensitive to the treatment with ZnO NPs than B. cinerea. SEM images and Raman spectra indicate two different antifungal activities of ZnO NPs against B. cinerea and P. expansum. ZnO NPs inhibited the growth of B. cinerea by affecting cellular functions, which caused deformation in fungal hyphae. In comparison, ZnO NPs prevented the development of conidiophores and conidia of P. expansum, which eventually led to the death of fungal hyphae. These results suggest that ZnO NPs could be used as an effective fungicide in agricultural and food safety applications. 相似文献
11.
Increases in cinnamate 4-hydroxylase and hydroxycinnamate:CoA ligase activities preceded the deposition of lignin around wounds in wheat leaves infecte 相似文献
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13.
Marcela Carvajal Alejandra Vergara Javier Contreras Mauricio Osorio Michael Seeger 《Fungal biology》2018,122(8):752-760
Terpenylated phenols possess interesting biological activities. These properties vary mainly according to the type of terpene associated and the degree of oxidation of the molecule. The search for new active molecules for application in different areas of knowledge includes the structural modification of these through ecological methodologies, such as biotransformation. The aims of this study were the biotransformation of geranylated- and acetylated-phloroglucinol by the fungus Gibberella fujikuroi and the evaluation of the antifungal activity of the derivatives. Five major derivatives were identified after biotransformation, highlighting the formation of specific monoacetylated products. In vitro antifungal activity assays against the phytopathogenic fungus Botrytis cinerea indicated that deacetylated derivatives possess higher activity compared to the precursor molecule. In other biotransformation reactions, a relationship between the release of the alkyl chain from the aromatic ring with a decrease of the antifungal activity, was observed. The in vivo tests in infected tomato plants with B. cinerea confirmed the antifungal activity of the derivatives observed in in vitro experiments. 相似文献
14.
Laccase (EC 1.10.3.2) from the culture filtrate of a strain of white rot basidiomycetePleurotus ostreatus was purified using DEAE-Toyopearl 650M and butyl-Toyopearl 650M column chromatographies and Superdex 75 HR 10/30 fast protein
liquid chromatography. Molecular weight of the purified laccase was about 55,000, and the isoelectric point was 3.0. The optimum
pH for enzyme activity was 6.5, and the optimum temperature was 50°C. This enzyme contained 7.4% sugar and two copper atoms
per molecule. The substrate specificity was similar to those of other fungal laccases. Comparison of the N-terminal amino
acid sequence of theP. ostreatus laccase with those fromPleurotus ostreatus Florida,Coriolus hirsutus, Phlebia radiata, basidiomycete PM1 (CECT 2971),Trametes villosa, Pycnoporus cinnabarinus, Ceriporiopsis subvermispora, andAgaricus bisporus showed 95, 65, 60, 55, 55, 55, 50, and 35% similarity, respectively, in the first 20 residues. No similarity in this region
was detected with laccases fromNeurospora crassa, Aspergillus nidulans, andCryptococcus neoformans. 相似文献
15.
Dereck P. Hucklesby Douglas M. James Marilyn J. Banwell Eric J. Hewitt 《Phytochemistry》1976,15(5):599-603
Nitrite reductase purified to homogeneity from vegetable marrow contains 2 atoms Fe/mol. Enzyme-bound iron exchanged extremely slowly with 59-Fe in solution. Acid-acetone extracts of the enzyme have a spectrum which is consistent with the presence of a sirohaem prosthetic group. Inhibition by mersalyl, which partially bleaches the enzyme, is reversible by glutathione only if this is added within a few min of mersalyl. The absorption spectra of the reduced and autoxidised enzyme and of the nitrite, cyanide and CO complexes are described. Amino acid composition data are given. The hydroxylamine reductase activity of the purified enzyme was 0.2% of nitrite reductase activity. 相似文献
16.
M.A. Metwally S. El-Dahmy J. Jakupovic F. Bohlmann A.M. Dawidar S.A. Metwally 《Phytochemistry》1985,25(1):255-257
The aerial parts of Cotula cinerea gave, in addition to widespread compounds, a characteristic diacetylenic spiroketal enolether and several sesquiterpene lactones, three of them being glaucolide-like lactones. The structures were elucidated by highfield 1H NMR spectroscopy. 相似文献
17.
采用冻干浓缩、(NH4)2S04盐析、HiTrapphenyl(FF)疏水层析和QSepharose FastFlow离子交换层析对灵芝EIM-40发酵液进行分离纯化,获得纯化漆酶,纯化倍数为14.6,回收率为5.3%。SDS-PAGE银染的结果为单一条带,相对分子质量约为6.53×104。以愈创木酚和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)为催化底物进行酶学性质研究,最适pH分别为4.8和4.5,最适温度分别为55和50℃,2种底物在pH4.0。5.0范围内,温度低于50℃时,酶的稳定性都很好。以愈创木酚为底物,Km=645.0umol/L;以ABTS为底物,Km=22.2txmol/L。Cu2+对该酶起激活作用,Fe2+、Ca2+、Ba2+则完全抑制酶的活性。 相似文献
18.
毛栓菌胞外漆酶的纯化及部分性质研究 总被引:9,自引:1,他引:9
毛栓菌胞外漆酶经盐析、透析、sephadexG75和G2 5四步纯化 ,粗酶液被纯化了 39 1倍 ,比活力 12 152 ,回收率 4 5 3%。漆酶最适pH值为 4 0 ,最适反应温度为 30℃。K Cu 2 、Zn2 离子可激活漆酶 ,而Ag 、Fe3 离子可抑制漆酶的活性。漆酶的Km值为 1 81× 10 3mol/L。 相似文献
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20.
Copper depletion of bacterial laccases obtained by heterologous expression in Escherichia coli is a common problem in production of these versatile biocatalysts. We demonstrate that coexpression of small soluble copper chaperones can mitigate this problem. The laccase CotA and the copper chaperone CopZ both from Bacillus licheniformis were used as model system. The use of the E. coli BL21(DE3) strain expressing CopZ and CotA simultaneously from two plasmids resulted in an 20% increase in copper occupancy and in 26% higher specific activity. We conclude that not only intracellular copper ion concentration, but also presence of an appropriate copper chaperone influences copper ion insertion into CotA laccase. Moreover, E. coli BL21(DE3) seems to lack such a copper chaperone which can be partially complemented by heterologous expression thereof. The presented system is simple and can routinely be used for improved heterologous production of bacterial laccase in E. coli. 相似文献