ABSTRACT
Over a period of one year the iodine content of the milk of 28 bavarian dairies was determined monthly by a gaschromatographical method. The annual mean value was 115 micrograms/l. In March, April and November, December, respectively a distinct increase of the concentration was observed. In the southern part of Bavaria the iodine contents were below 100 micrograms/l in contrast to the region Oberpfalz and Franken where contents up to 150 micrograms/l could be determined. Compared with concentrations in different tables the iodine content in bavarian milk could increase the iodine uptake up to 6%.
Subject(s)
Iodine/analysis , Milk/chemistry , Adolescent , Adult , Animals , Cattle , Child , Child, Preschool , Dairying , Female , Germany , Humans , Iodine/administration & dosage , Male , Nutritional RequirementsABSTRACT
The metabolism of the mycotoxin ochratoxin A in plant cells was investigated using cell suspension cultures of wheat and maize. A number of metabolites were detected by HPLC-chromatography with fluorescence detection. The main metabolites were ochratoxin alpha, ochratoxin A methyl ester, two isomers of hydroxyochratoxin A, and the glucosides and methyl esters of both hydroxyochratoxin A isomers. The compounds were isolated by TLC and preparative HPLC and identified by mass spectrometry and specific enzymic reactions.
Subject(s)
Mycotoxins/pharmacokinetics , Ochratoxins/pharmacokinetics , Triticum/metabolism , Zea mays/metabolism , Biotransformation , Carbon Radioisotopes , Cells, Cultured , Chromatography, High Pressure Liquid , Radiometry , Spectrometry, Fluorescence , Triticum/cytology , Zea mays/cytologyABSTRACT
Ochratoxin A, one of the most toxic mycotoxins, can be metabolized nearly completely by suspension cultures of various plant cells. The transformation products identified in this study were almost the same in the cell-suspension cultures of maize, carrot, tomato, potato, soybean, wheat and barley, but the quantitative distribution differed strongly depending on incubation time and species of plant-cell culture. The compounds were extracted with ethyl acetate and detected by reversed-phase HPLC with gradient elution. From the result it is supposed that besides ochratoxin A also ochratoxin derivatives may occur in food and feedstuff of plant origin.
Subject(s)
Crops, Agricultural/metabolism , Ochratoxins/metabolism , Biotransformation , Cells, Cultured , Crops, Agricultural/cytologyABSTRACT
The Fusarium mycotoxin zearalenone (ZEA), added at a level of 2 micrograms/ml, was reduced stereoselectively by cultures of Candida tropicalis, Torulaspora delbrückii, Zygosaccharomyces rouxii, and 7 Saccharomyces strains to both alpha- and beta-zearalenol. In contrast, only alpha-zearalenol was produced from ZEA by Pichia fermentans and several yeast strains of the genera Candida, Hansenula, Brettanomyces, Schizosaccharomyces, and Saccharomycopsis. No glucose conjugates of ZEA (zearalenone-4-beta-D-glucopyranoside) were detected. The trichothecene mycotoxin deoxynivalenol (DON) was not metabolized by any of the yeast strains that were used for analysis.
Subject(s)
Trichothecenes/pharmacokinetics , Yeasts/metabolism , Zearalenone/pharmacokinetics , Beer/microbiology , Biotransformation , Species Specificity , Time Factors , Wine/microbiology , Yeasts/growth & developmentABSTRACT
A total of 529 bacterial strains have been isolated from milk and cream sampled at different sites in a dairy production plant under conditions selective for aerobic sporeforming bacteria. Identification with classical methods based on morphological, physiological and biochemical criteria showed Bacillus licheniformis to be the most frequently occurring Bacillus sp. The investigation also revealed 62 unidentified strains. Classical identification methods were time consuming (3-7 d), lacked specificity and--because of their dependence on phenotypic gene expression--sometimes produced ambiguous results. Consequently, a colony hybridization method developed for the identification of B. licheniformis strains and using nonradioactive labelled 23S rRNA targeted oligonucleotide probes was also used. Identification of B. licheniformis with both classical and hybridization methods revealed diverging identification results for 70 strains.
Subject(s)
Bacillus/classification , Dairy Products/microbiology , Milk/microbiology , Animals , Bacillus/isolation & purification , Bacillus/physiology , Bacterial Typing Techniques/veterinary , Cattle , Female , Nucleic Acid Hybridization , Nucleic Acid ProbesABSTRACT
Non-commercial spices and herbs Tetrapleura tetrapetra, Triumfetta cordifolia, Garcina kola, Monodora myristica and Xylopia aethiopica at 0.08 to 0.32% (w/v) decreased the mycelial weight of Aspergillus parasiticus NRRL 2999 in yeast extract/sucrose broth by up to 68%. Aflatoxin production, monitored with ELISA, was most effectively decreased, from 97 to 23 µg/ml, when the extract of G. kola was added at 0.32% (w/v).
ABSTRACT
In order to determine to fungal growth of Fusarium graminearum 480, a method was developed for the extraction and estimation of ergosterol, a sterol specific for fungi. This method includes the direct saponification of bound ergosterol to fungal mycelia followed by n-hexane extraction and quantification using. High performance liquid chromatography (HPLC) with UV-detection. This procedure proved to be superior compared with other methods, since the yield of ergosterol yields was higher (up to 40%). n-Hexane extracts contained minor impurities which interfered with the UV-detection and the retention time of the compound was halved using Si 60 HPLC. The protein and ergosterol contents in F. graminearum cultures increased proportionally over a 3-week incubation period. The fungal formation of the mycotoxin zearalenone started at a level of 50 mg/kg ergosterol and increased rapidly in the stationary phase of growth, which was characterized by decreasing rates of ergosterol formation.
Subject(s)
Ergosterol/analysis , Fusarium/growth & development , Chromatography, High Pressure Liquid , Fungal Proteins/analysis , Fusarium/metabolism , Zearalenone/analysisABSTRACT
Several semisynthetic liquid media were examined for the large-scale production of deoxynivalenol (DON) und 3-acetyldeoxynivalenol (AcDON) by Fusarium graminearum 183. Only in three of the eight media used could high toxin yields of DON and AcDON be detected. The maximum levels of DON in a medium according to Miller were 3 mg/l and of AcDON 32 mg/l. In glucose-yeast extract-peptone (GYEP) medium containing 1% glucose, the AcDON concentrations reached 33 mg/l and the DON yields were 19 mg/l. In a rice flour liquid medium, however, the mean levels of AcDON and DON increased to 170 mg/l and 9 mg/l, respectively. The maximum amounts observed were 480 mg/l for AcDON and 65 mg/l for DON. The addition of trifluoracetic acid sodium salt or malonic acid, which are suggested to cause an accumulation of acetyl-CoA by inhibiting enzymes of the tricarboxylic acid cycle, did not stimulate the toxin formation.
Subject(s)
Food Microbiology , Fusarium/metabolism , Mycotoxins/biosynthesis , Sesquiterpenes/biosynthesis , Trichothecenes/biosynthesis , Culture Media , Flour/analysis , Germany, West , Kinetics , Time FactorsABSTRACT
Di-n-butyl phthalate and other dialkyl phthalates are used as carbon sources by three Nocardia sp. isolates; mono-n-butyl phthalate is used as a carbon source by an Arthrobacter sp. isolate and a Pseudomonas sp. isolate. The compounds were metabolized in these organisms by hydrolysis to the corresponding monoesters and free phthalic acid. Phthalic acid was then metabolized via protocatechuic acid by 3,4-dioxygenative ring cleavage.
ABSTRACT
4-(Methylmercapto)-phenol (MMP) and 4-(methylsulfinyl)-phenol (MSP) are oxidized by the soil isolate Nocardia spec. DSM 43251, which is closely related to Nocardia calcarea. The rate of degradation depends on the capability of a substrate to support growth and is strongly enhanced in the presence of a second carbon source under the conditions of cooxidation. MMP and MSP are cometabolized by hydroxylation of the benzene ring with the formation of the substituted catechol following by ring cleavage between carbon atoms 2 and 3 ("meta" fission) to give 2-hydroxy-5-methylmercapto-or-2-hydroxy-5-methylsulfinylmuconic semialdehyde. Oxidation of MMP to MSP represents a bypath of MMP-oxidation. The intermediates were identified on the basis of their physical properties. The enzymes responsible for the metabolism of MMP and MSP are induced by growth with MMP or MSP, but not with glucose. MMP-and MSP-induced cells catalyze the oxidation of a variety of substituted phenols. This indicates a rather low substrate specificity of the enzymes induced by MMP and MSP.
Subject(s)
Nocardia/metabolism , Organomercury Compounds/metabolism , Phenols/metabolism , Soil Microbiology , Acetates/metabolism , Ascorbic Acid/metabolism , Biodegradation, Environmental , Catechols , Fumarates/metabolism , Nocardia/enzymology , Nocardia/growth & development , Oxidation-Reduction , Oxygenases/metabolism , Pyruvates/metabolism , Succinates/metabolismABSTRACT
The degradation of the phenylamide herbicides monolinuron, linuron, and solan by cultures of Bacillus sphaericus ATCC 12123 was inhibited by the methylcarbamate insecticides metmercapturon, aldicarb, propoxur, and carbaryl and by the organophosphorus insecticides fenthion and parathion. The extent of inhibition was largest with metmercapturon and smallest with parathion inhibition of hydrolysis of the two phenylurea herbicides was greater than of the acylanilide compound. Tests with crude enzyme preparations of aryl acylamidase derived from B. sphaericus showed that the inhibition of the hydrolysis of linuron with methylcarbamates is a competitive one. The insecticides tested did induce the enzyme, nor could they serve as its substrate.
Subject(s)
Bacillus/metabolism , Carbamates , Herbicides/metabolism , Insecticides/pharmacology , Organophosphorus Compounds , Soil Microbiology , Amidohydrolases/metabolism , Bacillus/enzymology , Biodegradation, Environmental , Carbon Radioisotopes , Cell-Free System , Depression, Chemical , Enzyme Induction , Herbicides/pharmacology , Hydrolysis , Linuron/metabolism , Toluidines/pharmacologyABSTRACT
From Bacillus sphaericus ATCC 12123 an aryl acylamidase (EC 3.5.1.13) was purified to homogeneity by ion exchange chromatography, gel filtration, and polyacrylamide gel electrophoresis. The enzyme is inducible by various phenylamides of the acylanilide, phenylcarbamate, and methoxysubstituted phenylurea type. It has a molecular weight of 75,000. Enzyme activity was inhibited by sulfhydryl reagents, several metal ions, and 3,4-dichloroaniline (a product of linuron degradation). A requirement for divalent metal ions in enzyme activity could not be demonstrated. In the presence of 6 M urea an irreversible inactivation of the enzyme occurred. The hydrolysis of L-alanine-4-nitroanilide was competitively inhibited by puromycin.
Subject(s)
Amides/metabolism , Amidohydrolases/analysis , Bacillus/enzymology , Fungicides, Industrial , Herbicides , Amidohydrolases/antagonists & inhibitors , Amidohydrolases/isolation & purification , Bacillus/drug effects , Buffers , Calcium Phosphates , Carbon Radioisotopes , Chromatography, DEAE-Cellulose , Chromatography, Gel , Culture Media , Electrophoresis, Polyacrylamide Gel , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Linuron/metabolism , Metals/pharmacology , Molecular Weight , Penicillin G/pharmacology , Protamines , Puromycin/pharmacology , TemperatureABSTRACT
N, O-dimethylhydroxylamine was identified as a degradation product of linuron formed in the presence of extracts of Bacillus sphaericus ATCC 12123 by characterization of its dinitrophenyl derivative.
Subject(s)
Bacillus/metabolism , Herbicides/metabolism , Hydroxylamines/biosynthesis , Urea/metabolism , Biodegradation, Environmental , Chemical Phenomena , Chemistry , Chromatography, Thin Layer , Fluorine , Hydroxylamines/analysis , Linuron/metabolism , NitrobenzenesABSTRACT
Linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] induces the formation of an enzyme (acylamidase) responsible for the degradation of a large variety of different herbicides and fungicides of the acylanilide and phenylurea type. The former type is degraded at a rate at least 10 times higher than the latter.
Subject(s)
Amidohydrolases/metabolism , Anilides/metabolism , Bacillus/enzymology , Fungicides, Industrial/metabolism , Herbicides/metabolism , Urea/metabolism , Aniline Compounds/biosynthesis , Bacillus/growth & development , Benzoates/biosynthesis , Carbon Dioxide/biosynthesis , Carboxylic Acids/biosynthesis , Cell-Free System , Chemical Phenomena , Chemistry , Chloramphenicol , Chromatography, Gas , Chromatography, Gel , Chromatography, Paper , Chromatography, Thin Layer , Culture Media , Electrophoresis, Disc , Enzyme Induction , SpectrophotometryABSTRACT
N'-methoxy phenylurea herbicides are degraded by induced cells of Bacillus sphaericus ATCC 12123 by liberating carbon dioxide from the ureido portion of the molecule and leaving the corresponding aniline moieties. Cell-free extracts of B. sphaericus inactivate these herbicides in the same way as reported for whole cells. A 6.6-fold purification of the crude extract was achieved by a combination of salt fractionation with ammonium sulfate and column chromatography on diethyl-aminoethyl cellulose.