Excretion kinetics and metabolism of zearalenone in broilers in dependence on a detoxifying agent

Two experiments were carried out with male broilers to examine excretion kinetics of zearalenone (ZON) and its metabolites and their occurrence in blood plasma and bile fluid after a single oral dose of ZON (approximately 6 μg/kg BW) from naturally contaminated wheat (406 μg ZON per kg). In addition, this ZON bolus was administered either in the absence or presence of a detoxifying agent (Mycofix®‐Plus, Biomin GmbH, Herzogenburg, Austria). Specimens were sampled after administration of the zearalenone bolus at different times of up to 48 h.

Excretion of zearalenone and α‐zearalenol as the only detectable metabolite of ZON peaked at approximately 6.5 h after administration of the bolus. Cumulative excretion of both substances amounted to approximately 58% of ZON intake after 48 h, when a plateau was achieved. The incomplete recovery could have been due to a partial total degradation of ZON in the digestive tract, undetected sulfate conjugates of ZON or its metabolites, to other unknown and undetected metabolites or to incomplete analytical recovery from the matrix, and needs to be examined further.

Peak concentrations of zearalenone and a‐zearalenol in bile were detected in the time period of approximately 2 to 6 h after bolus, whereas ZON and metabolite concentrations in blood plasma were around or lower than the detection limits. Mycofix®‐Plus supplementation seemed to have only minor or no effects on the parameters examined.     

Purine cytokinin nomenclature: a working system of abbreviations

Many synonyms for the cytokinin 6-(benzylamino)purine and its metabolites have arisen in the literature despite a 1970 IUPAC-IUB directive delimiting such nomenclature. Examples of symbols and abbreviations for some classes of this cytokinin are given. The reasons for this continued synonomy are attributed to difficulties associated with the IUPAC-IUB recommendations. A modified system of abbreviations is presented in tabular form and the utility of the scheme discussed.     

Occurrence of zearalenone in maize

The occurrence of zearalenone in whole plants and parts of maize usually used for silage making was investigated during the cultivation period of the crop. Zearalenone was detected upto several hundreds of μg/kg DM, that mainly accumulated at the end of the ripening process thus contaminating the silages subsequently. The highest concentrations of zearalenone were observed in the leaves especially at the bottom of the plant, which may correlate with leaf necrosis increasing towards harvest. Further research is needed to clarify health risks for farm animals due to uptake of contaminated feed and possible carry-over of zearalenone and its metabolites into the food chain of man.     

Determination of zearalenone and its metabolites in urine, plasma and faeces of horses by HPLC-APCI-MS

The paper describes a method for the sensitive and selective determination of zearalenone and its metabolites in urine, plasma and faeces of horses by high performance liquid chromatography and atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS). While only one step sample clean-up by an immunoaffinity column (IAC) was sufficient for plasma samples, urine and faeces samples had to be prepared by a combination of a solid-phase extraction (SPE) and an immunoaffinity column. The method allows the simultaneous determination of zearalenone and all of its metabolites; alpha-zearalenol, beta-zearalenol, alpha-zearalanol, beta-zearalanol and zearalanone. Dideuterated zearalanone was used as internal standard for quantification and the study of the matrix effect. Recovery rates between 56 and slightly above 100% were achieved in urine samples, and more than 80% in plasma and faeces samples. The limits of detection ranged from 0.1-0.5 microg/l or microg/kg, the limits of quantification from 0.5-1.0 microg/l or microg/kg. The practical use of the method is demonstrated by the analysis of spiked and naturally contaminated urine, plasma and faeces of horses.     

Formation of Fusarium metabolites in barley grain

Summary The influence of moisture content and temperature during storage of grain on the formation of Fusarium metabolites was studied. Naturally and artificially contaminated barley grain samples were stored at 15%, 25%, and 30% moisture contents, and at temperatures of + 5°C + 25°C, and + 30°C. Time of storage varied between one week and six months and the occurrence of Fusarium species and metabolites was analysed. The only Fusarium metabolite detected was zearalenone. The extent of Fusarium contamination decreased during storage whilst the concentration of zearalenone increased. To avoid the danger of mycotoxicoses, grains must be dryed immediately after harvest and then stored at a low temperature.     

Bioconversion of alpha-[14C]zearalenol and beta-[14C]zearalenol into [14C]zearalenone by Fusarium roseum 'Gibbosum'

Cultures of Fusarium roseium 'Gibbosum' on rice were treated with [14C]zearalenone, alpha[14C]zearalenol, or beta-[14C]zearalenol to determine whether a precursor-product relationship exists among these closely related fungal metabolites. Culture extracts were purified by silica gel column chromatography and fractionated by high-pressure liquid chromatography, and the level of radioactivity was determined. Within 7 days, the beta-[14C]zearalenol was converted to zearalenone, and no residual beta-[14C]zearalenol was detectable. Most of the alpha-[14C]zearalenol added was also converted into zearalenone with 14 days. In cultures treated with [14C]zearalenone, no radioactivity was noted in any other components.     

Bioconversion of alpha-[14C]zearalenol and beta-[14C]zearalenol into [14C]zearalenone by Fusarium roseum 'Gibbosum'.

Cultures of Fusarium roseium 'Gibbosum' on rice were treated with [14C]zearalenone, alpha[14C]zearalenol, or beta-[14C]zearalenol to determine whether a precursor-product relationship exists among these closely related fungal metabolites. Culture extracts were purified by silica gel column chromatography and fractionated by high-pressure liquid chromatography, and the level of radioactivity was determined. Within 7 days, the beta-[14C]zearalenol was converted to zearalenone, and no residual beta-[14C]zearalenol was detectable. Most of the alpha-[14C]zearalenol added was also converted into zearalenone with 14 days. In cultures treated with [14C]zearalenone, no radioactivity was noted in any other components.     

Measurement of the relative binding affinity of zearalenone, alpha-zearalenol and beta-zearalenol for uterine and oviduct estrogen receptors in swine, rats and chickens: an indicator of estrogenic potencies

1. The relative binding affinity of zearalenone, alpha-zearalenol, and beta-zearalenol for estrogen receptors was determined in the pig, rat and chicken. 2. Similar relative binding patterns were observed, with alpha-zearalenol exhibiting greater affinity than zearalenone and beta-zearalenol the least binding affinity in all species. 3. The relative binding affinity of alpha-zearalenol was greater in pig, than in rat and significantly greater than in chicken. 4. Interspecies differences in zearalenone sensitivity may be due to the binding affinity of alpha-zearalenol for estrogen receptors and differences in zearalenone metabolites formed.     

Measurement of the relative binding affinity of zearalenone, α-zearalenol and β-zearalenol for uterine and oviduct estrogen receptors in swine,rats and chickens: An indicator of estrogenic potencies

1. The relative binding affinity of zearalenone, α-zearalenol and β-zearalenol for estrogen receptors was determined in the pig, rat and chicken.2. Similar relative binding patterns were observed, with a-zearalenol exhibiting greater affinity than zearalenone and β-zearalenol the least binding affinity in all species.3. The relative binding affinity of α-zearalenol was greater in pig, than in rat and significantly greater than in chicken.4. Interspecies differences in zearalenone sensitivity may be due to the binding affinity of α-zearalenol for estrogen receptors and differences in zearalenone metabolites formed.     

Role of zearalenone lactonase in protection of Gliocladium roseum from fungitoxic effects of the mycotoxin zearalenone

Zearalenone is a mycotoxin with estrogenic effects on mammals that is produced by several species of Fusarium. We found that zearalenone and its derivatives inhibit the growth of filamentous fungi on solid media at concentrations of < or =10 microg/ml. The fungitoxic effect declined in the order zearalenone > alpha-zearalenol > beta-zearalenol. The mycoparasitic fungus Gliocladium roseum produces a zearalenone-specific lactonase which catalyzes the hydrolysis of zearalenone, followed by a spontaneous decarboxylation. The growth of G. roseum was not inhibited by zearalenone, and the lactonase may protect G. roseum from the toxic effects of this mycotoxin. We inactivated zes2, the gene encoding zearalenone lactonase in G. roseum, by inserting a hygromycin resistance cassette into the coding sequence of the gene by means of Agrobacterium tumefaciens-mediated genetic transformation. The zes2 disruption mutants could not hydrolyze the lactone bond of zearalenone and were more sensitive to zearalenone. These data are consistent with a hypothesis that resorcylic acid lactones exemplified by zearalenone act to reduce growth competition by preventing competing fungi from colonizing substrates occupied by zearalenone producers and suggest that they may play a role in fungal defense against mycoparasites.     

Biosynthesis,isolation, purification and seperation of Zearalenone,deoxynivalenol and 15-Acetyldeoxynivalenol

Fusarium graminearum KF-376 isolate was found to be able to form simultaneously three toxic metabolites: zearalenone (FF-2), deoxynivalenol (DON) and 15-acetyldeoxynivalenol (15-AcDON). Toxins were extracted with methanol — water 3:1 (v/v) and purified by liquid chromatography on charcoal — Kieselgel 60 column (preliminary) and Aluminiumoxid 90 column. Final separation of the metabolites was achived on Kieselgel 60 — Aluminiumoxid 90 column.     

Biosynthesis,isolation, purification and separation of nivalenol,fusarenone — X and zearalenone

Fusarium, graminearum KF 370 isolate is able to simultaneous biosynthesis of three toxic metabolites, namely: fusarenone-X (FUS), nivalenol (NIV) and zearalenone (F-2). After metabolites extraction with methanol — water (3:1) and defatting with n-heptane toxins were partitioned into chloroform layer. Purification of the? compounds was performed on Celite 545 — charcoal — Aluminiumoxid 90 column then metabolites were separated on Kieselgel 60 (200–300 mesh) column with developing solvent chloroform — methanol. This way FUS, NIV and F-2 were obtained as crystalline or high purity standards.     

Role of Zearalenone Lactonase in Protection of Gliocladium roseum from Fungitoxic Effects of the Mycotoxin Zearalenone

Zearalenone is a mycotoxin with estrogenic effects on mammals that is produced by several species of Fusarium. We found that zearalenone and its derivatives inhibit the growth of filamentous fungi on solid media at concentrations of ≤10 μg/ml. The fungitoxic effect declined in the order zearalenone > α-zearalenol > β-zearalenol. The mycoparasitic fungus Gliocladium roseum produces a zearalenone-specific lactonase which catalyzes the hydrolysis of zearalenone, followed by a spontaneous decarboxylation. The growth of G. roseum was not inhibited by zearalenone, and the lactonase may protect G. roseum from the toxic effects of this mycotoxin. We inactivated zes2, the gene encoding zearalenone lactonase in G. roseum, by inserting a hygromycin resistance cassette into the coding sequence of the gene by means of Agrobacterium tumefaciens-mediated genetic transformation. The zes2 disruption mutants could not hydrolyze the lactone bond of zearalenone and were more sensitive to zearalenone. These data are consistent with a hypothesis that resorcylic acid lactones exemplified by zearalenone act to reduce growth competition by preventing competing fungi from colonizing substrates occupied by zearalenone producers and suggest that they may play a role in fungal defense against mycoparasites.     

MBA: a literature mining system for extracting biomedical abbreviations

Background  

The exploding growth of the biomedical literature presents many challenges for biological researchers. One such challenge is from the use of a great deal of abbreviations. Extracting abbreviations and their definitions accurately is very helpful to biologists and also facilitates biomedical text analysis. Existing approaches fall into four broad categories: rule based, machine learning based, text alignment based and statistically based. State of the art methods either focus exclusively on acronym-type abbreviations, or could not recognize rare abbreviations. We propose a systematic method to extract abbreviations effectively. At first a scoring method is used to classify the abbreviations into acronym-type and non-acronym-type abbreviations, and then their corresponding definitions are identified by two different methods: text alignment algorithm for the former, statistical method for the latter.     

Paper chromatographic assay of ( 3 H)norepinephrine and its five major metabolites

The technique described here offers several advantages over the currently available assays for [³H]norepinephrine and its metabolites. The technique is simpler and has fewer sources of potential error than most currently available techniques. It provides a complete separation of norepinephrine from its five major metabolites with virtually no cross-contamination between the fractions. It is unnecessary to correct for recovery, elution from the chromatograms, or efficiency of counting the chromatogram segments. Experiments reported here demonstrate that all five major metabolites of norepinephrine are formed by rabbit aorta. Most of the neutral metabolites and normetanephrine are found in the Krebs solution used for incubating the tissue, whereas most of the acid metabolites are found in the tissue.     

Cytotoxicity of Fusarium species mycotoxins and culture filtrates of Fusarium species isolated from the medicinal plant Tribulus terrestris to mammalian cells

Ayurvedic medicine, which uses decoctions made of medicinal plants, is used to cure diseases in many Asian countries including Sri Lanka. Although proper storage facilities for medicinal plants are unavailable in Sri Lanka, neither the potential for growth of toxigenic fungi nor their ability to produce mycotoxins in stored medicinal plants has been investigated. We isolated three Fusarium species, F. culmorum, F. acuminatum and F. graminearum from the medicinal plant Tribulus terrestris. Culture extracts of the 3 Fusarium spp. were cytotoxic to mammalian cell lines BHK-21 and HEP-2. Three toxic metabolites produced by Fusarium spp; T-2 toxin, zearalenone, and diacetoxyscirpenol were also cytotoxic to the same mammalian cell lines. The 3 Fusarium spp. grown on rice media produced zearalenone. Plant material destined for medicinal use should be stored under suitable conditions to prevent growth of naturally occurring toxigenic fungi prior to its use.     

Cytotoxicity of fungal metabolites to lepidopteran (Spodoptera frugiperda) cell line (SF-9)

The toxicity of sixteen fungal metabolites produced by some entomopathogenic fungi or biological control fungi agents was evaluated on lepidopteran Spodoptera frugiperda (SF-9) cell line by Trypan blue dye exclusion and MTT-colorimetric assay, after 48 h of incubation. No statistical difference was found between IC50values (50% Inhibiting Concentration) and CC50 values (50% Cytotoxicity Concentration) obtained by MTT test and Trypan blue dye exclusion for each fungal metabolite. By MTT assay, the cytotoxicity ranking was fusarenon X (IC50 0.3 microM) = diacetoxyscirpenol (IC50 0.5 microM) = beauvericin (IC50 2.5 microM) = nivalenol (IC50 5.3 microM) = enniatin (IC50 6.6 microM) > or = gliotoxin (IC50 7.5 microM) > zearalenone (IC50 17.5 microM) > deoxynivalenol (IC50 47.6 microM). By Trypan blue dye exclusion the cytotoxicity ranking was fusarenon X (CC50 0.4 microM) = diacetoxyscirpenol (CC50 1.1 microM) beauvericin = (CC50 3.0 microM)=gliotoxin (CC50 4.0 microM) = enniatin (CC50 6.7 microM) > or = nivalenol (CC50 9.5 microM) > zearalenone (CC50 18.3 microM) > deoxynivalenol (CC50 45.0 microM). The comparison with other bioassays showed that the SF-9 insect cell line could represent a further tool to screen for the toxic effects of fungal metabolites especially for beauvericin, gliotoxin, and zearalenone.     

Degradation of dibenzothiophene by Brevibacterium sp.DO

Dibenzothiophene, a polycyclic aromatic sulfur heterocycle, represents as a model compound the organic sulfur integrated in the macromolecular coal matrix. A pure culture of a Brevibacterium species was isolated, which is able to use dibenzothiophene as sole source of carbon, sulfur and energy for growth. During dibenzothiophene utilization sulfite was released in a stoichiometrical amount and was further oxidized to sulfate. Three metabolites of dibenzothiophene degradation were isolated and identified as dibenzothiophene-5-oxide, dibenzothiophene-5-dioxide and benzoate by cochromatography, UV spectroscopy and gas chromatographymass spectrometry analyses. Based on the identified metabolites a pathway for the degradation of dibenzothiophene by Brevibacterium sp. DO is proposed.Non-standard abbreviations DBT dibenzothiophene - PASH polycyclic aromatic sulfur heterocycle - PAH polycyclic aromatic hydrocarbons - GC-MS gas chromatography-mass spectrometry - HPLC high pressure liquid chromatography - IC ion chromatography     

Cultural characteristics and zearalenone production by strains of<Emphasis Type="Underline">Fusarium</Emphasis> from wheat

Conidia of the speciesFusarium culmorum /W.G.Sm./ Sacc. andFusarium graminearum Schwabe are characterized by variability in zearalenone production and dimensions depending on the substrate. The sporulation of isolates from some wheat eultivars have been deprived in vivo and in vitro in the first passage, but not their pathogenicity and toxic metabolites production. Nonsporulating strains produced lower quantités of zearalenone than sporulating ones. Liquid filtrates of such nonsporulating strains had a high phytotoxic effect on wheat caryopses. The crystalline toxin DAS /0,25 ug/ml/ had low phytotoxic effect on wheat caryopses.     

Mouse bioassay for Fusarium metabolites: rejection or acceptance when dissolved in drinking water.

Ten metabolites of Fusarium species (butenolide, diacetoxyscirpenol, equisetin, fusaric acid, gibberellic acid, moniliformin, NRRL 6227 peptide, T-2 toxin, vomitoxin, and zearalenone) were added to the drinking water of mice to determine whether they were consumed or refused. Of the 10, only the trichothecenes--diacetoxyscirpenol, T-2 toxin, and vomitoxin--were refused. Refusal of 2 mg of the trichothecenes per liter was not enhanced by adding 100 mg of zearalenone per liter.