Glucose oxidase as the antifungal principle of talaron from Talaromyces flavus

1990 ◽  
Vol 36 (11) ◽  
pp. 760-764 ◽  
Author(s):  
Kay Kwang-Ae Kim ◽  
Deborah R. Fravel ◽  
G. C. Papavizas
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Antimicrobial Activity ◽  
Glucose Oxidase ◽  
Verticillium Dahliae ◽  
Sodium Dodecylsulfate ◽  
Authentic Sample ◽  
Fluorescence Emission ◽  
Excitation Wavelength ◽  
Talaromyces Flavus

Analysis of an authentic sample of the antifungal antibiotic talaron from the biocontrol fungus Talaromyces flavus indicated that approximately 40% of the solid sample was glucose oxidase. High-performance liquid chromatography elution profiles of the antimicrobial activity of talaron coeluted with those of glucose oxidase. Fluorescence emission and excitation wavelength maxima for talaron were similar to those of glucose oxidase from Aspergillus niger. The molecular weight of talaron was 152 000 with a subunit molecular weight of 71 000. The isoelectric point of talaron was pH 4.2. Mobilities of talaron on native, sodium dodecylsulfate, and isoelectric focusing polyacrylamide gels were identical with those of glucose oxidase produced by T. flavus. Furthermore, talaron had antimicrobial activity only in the presence of glucose. Hydrogen peroxide produced by the action of glucose oxidase is toxic to Verticillium dahliae. This study indicates that the antifungal activity of authentic talaron resulted from glucose oxidase produced by T. flavus. Key words: biological control, glucose oxidase, hydrogen peroxide, talaron, Talaromyces flavus, Verticillium dahliae.

Production, purification, and properties of glucose oxidase from the biocontrol fungus Talaromyces flavus

1990 ◽  
Vol 36 (3) ◽  
pp. 199-205 ◽  
Author(s):  
Kay K. Kim ◽  
Deborah R. Fravel ◽  
George C. Papavizas
Keyword(s):  
Glucose Oxidase ◽  
High Performance ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecylsulfate ◽  
Native Enzyme ◽  
Purification And Properties ◽  
Talaromyces Flavus ◽  
Optimum Ph ◽  
Extracellular Glucose ◽  
Type Population

Talaromyces flavus produces the enzyme glucose oxidase, which may be involved in biocontrol of the fungal plant pathogen, Verticillium dahliae. A strain of T. flavus was selected from the wild-type population for the production of extracellular glucose oxidase, and the enzyme was purified by a combination of acetone precipitation and high performance liquid chromatography (HPLC). Approximately 12–25 mg of pure protein was obtained from 2 L of culture, and the total recovered activity ranged from 5 to 10 × 103 μmol/min. Homogeneity of the purified enzyme was demonstrated by HPLC and by native and sodium dodecylsulfate polyacrylamide gel electrophoresis. Molecular weight of the native enzyme was 164 000 and that of the subunit was71 000, which indicated that the native enzyme is a dimer. The apparent Km value for D-glucose was 10.9 mM. The optimum pH for the enzyme activity was 5.0, but the enzyme was stable in buffer from pH 3 to 7. The enzyme was observed to be a glycoprotein, and amino acid analysis of the purified enzyme indicated a similarity to glucose oxidases from fungal sources. Isozymes of the enzyme with pI values of 4.40–4.55 were detected on analytical isoelectric focusing gels. Key words: antibiosis, biocontrol, glucose oxidase, Talaromyces flavus.

A Novel Near-Infrared Fluorescence Sensor for H2O2 Based on N-Acetyl-L-Cysteine-Capped Gold Nanoparticles

2017 ◽  
Vol 46 ◽  
pp. 234-240
Author(s):  
Wen Juan Dong ◽  
Ji Yan Han ◽  
Xin Wu ◽  
Li Fan ◽  
Wen Ting Liang
Keyword(s):  
Hydrogen Peroxide ◽  
Gold Nanoparticles ◽  
Fluorescence Quenching ◽  
Near Infrared ◽  
Fluorescence Probe ◽  
Fluorescence Emission ◽  
Excitation Wavelength ◽  
Experimental Conditions ◽  
Time Resolved ◽  
Near Infrared Fluorescence

A novel near-infrared fluorescence quenching method has been developed for the determination of hydrogen peroxide based on N-acetyl-L-cysteine-capped gold nanoparticles (NAC-AuNPs) as a fluorescence probe. The prepared gold nanoparticles with the size of about 1.91 nm exhibited strong near-infrared fluorescence emission at 693 nm with excitation wavelength at 450 nm in aqueous solution. The fluorescence intensity of NAC-AuNPs was quenched dramatically by adding hydrogen peroxide. Therefore, it could be used to detect hydrogen peroxide based on the fluorescence quenching intensity was linear with the concentration of hydrogen peroxide. Under the optimal experimental conditions, the linear range and detection limit were 1.0×10-6 –3.0×10-2 mol/L and 1.0×10-7 mol/L, respectively. The possible quenching mechanism was investigated by time-resolved fluorescence spectroscopy. The proposed method was simple, sensitive and showed good repeatability and stability.

scholarly journals Enzymatically triggered rupture of polymersomes

Soft Matter ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1014-1020 ◽  
Author(s):  
Woo-Sik Jang ◽  
Seung Chul Park ◽  
Ellen H. Reed ◽  
Kevin P. Dooley ◽  
Samuel F. Wheeler ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase

Polymersomes are robust vesicles made from di-block co-polymers. We have engineered a two step enzymatic cascade to trigger the release of contents from polymersomes, in which extravesicular glucose oxidase makes hydrogen peroxide, when then penetrates the membrane and is converted by entrapped catalase to oxygen, leading to vesicle failure.

TICT fluorescence emission dependence on excitation wavelength for ethyl p-(dimethylamino)benzoate in supercritical trifluoromethane

1989 ◽  
Vol 111 (5) ◽  
pp. 1915-1916 ◽  
Author(s):  
Bruce J. Hrnjez ◽  
Parvin T. Yazdi ◽  
Marye Anne Fox ◽  
Keith P. Johnston
Keyword(s):  
Fluorescence Emission ◽  
Excitation Wavelength

scholarly journals Antimicrobial activity of fifteen Italian honeys against Paenibacillus larvae ATCC 9545

2018 ◽  
Vol 68 (4) ◽  
pp. 547 ◽  
Author(s):  
S. SAGONA ◽  
B. TURCHI ◽  
F. FRATINI ◽  
M. GIUSTI ◽  
B. TORRACCA ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Glucose Oxidase ◽  
Inhibitory Activity ◽  
Oxidase Activity ◽  
Gluconic Acid ◽  
Total Flavonoid ◽  
Paenibacillus Larvae ◽  
Economic Losses ◽  
Total Phenolic ◽  
Honey Sample

Currently, American Foulbrood (AFB) represents one of the most important problems for beekeepers, due to economic losses and to the absence of an effective therapeutic treatment. The aim of this work was to characterize fifteen Italian honeys in order to assess their inhibitory activity against Paenibacillus larvae ATCC 9545. Each honey was analyzed for the activity of the following enzymes: glucose oxidase and catalase. Moreover, melissopalynological analysis and other biochemical parameters, namely gluconic acid, total phenolic and total flavonoid contents were determined. For each honey, the Minimum Inhibitory Concentration (M.I.C.) and the Minimum Bactericidal Concentration (M.B.C.) against P. larvae were determined. All tested honey samples had an inhibitory activity on P. larvae. In particular, the lowest M.I.C. and M.B.C. values (53.8 mg/mL and 107.5 mg/mL, respectively) were recorded for an Arbutus honey sample. Arbutus honeys also had the highest gluconic acid and total phenolic contents (12.6 ± 1.7 g/kg and 243.2 ± 25.1 mg/kg, respectively) and the highest glucose oxidase activity (13.0 ± 1.9 nM H2O2/min). Dark honeys, including Arbutus, seem to have a higher gluconic acid content and a higher antimicrobial activity. Thus, honey characterization, including colour and physico-chemical characteristics (e.g. gluconic acid concentration, total phenolic and total flavonoid contents, glucose oxidase activity), could be crucial for the assessment of its employment against P. larvae.

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