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Mórahalom, Hungary

Kredics L.,University of Szeged | Laday M.,Hungarian Academy of Sciences | Kormoczi P.,University of Szeged | Manczinger L.,University of Szeged | And 3 more authors.
Acta Biologica Szegediensis

One hundred and sixteen Trichoderma isolates were collected from chopped roots of winter wheat of five agricultural fields in the Great Hungarian Plain. The isolates were identified by the sequence analysis of the internal transcribed spacer (ITS) region with TrichOKEY 2.0 and BLAST similarity searches. The Trichoderma species detected in the samples were T. atroviride, T. brevicompactum, T. gamsii, T. harzianum, T. koningiopsis/T. ovalisporum, T. longibrachiatum/H. orientalis, T. pleuroticola, T. rossicum, T. spirale, T. tomentosum/T. cerinum and T. virens. Beneficial taxa widely used as biocontrol agents against plant pathogenic fungi (e.g. T. harzianum, T. virens, T. atroviride) could be isolated from the samples examined during this study, indicating that the winter wheat rhizosphere may be a rich source of potential biocontrol isolates. Several species could be characterized with well-defined isoenzyme patterns during cellulose-acetate electrophoresis, suggesting that this method can be used for the analysis of biochemical diversity between and within particular species of the genus Trichoderma. Source

Nagy G.,University of Szeged | Imre G.,University of Szeged | Csernetics A.,University of Szeged | Petkovits T.,University of Szeged | And 4 more authors.
Acta Biologica Szegediensis

In this study, a prenyl pyrophosphate synthase gene was cloned and characterized in the zygomycete fungus Gilbertella persicaria. The coding region of the isolated gene comprises a total of 1328 bp determining a 350 amino acids length putative protein and five introns (60, 65, 43, 59, and 48 bp in length) dispersed in the whole coding region. Based on the analysis of the nucleotide and the corresponding amino acid sequence, the gene encodes a farnezyl pyrophosphate synthase, and it was named as isoA. In a phylogeny inferred from amino acid sequences of fungal prenyl pyrophosphate synthases, the Gilbertella isoA proved to be the most closely related to that of Mucor circinelloides. Carotenoid composition of G. persicaria was also investigated: it produces β-carotene as the main carotenoid, but it also contains small amounts of β-cryptoxanthin, zeaxanthin and astaxanthin. Source

Varga J.,University of Szeged | Kocsube S.,University of Szeged | Suri K.,University of Szeged | Szigeti G.,University of Szeged | And 4 more authors.
International Journal of Food Microbiology

Aspergillus niger isolates are able to produce fumonisins in high quantities on agar media with a low water activity. Several agricultural products fit this criterion, including dried vine fruits, dates and figs. Data on the occurrence and role of this species in fumonisin contamination of agricultural products with high sugar content are needed to clarify the importance of A. niger in human health. The mycobiota and fumonisin contamination of various dried vine fruit samples collected from different countries were examined to clarify the role of black Aspergilli in fumonisin contamination of such products. All except two of the examined samples were contaminated with black Aspergilli. Species assignment of the isolates was carried out using sequence analysis of part of the calmodulin gene. The range of fumonisin isomers present in the raisin samples, and produced by A. niger isolates collected from dried vine fruits was also examined using reversed-phase high-performance liquid chromatography/electrospray ionization-ion trap mass spectrometry (RP-HPLC/ESI-ITMS). Among the 30 A. niger/A. awamori isolates identified, 20 were found to be able to produce fumonisins (average contamination: 5.16mg/kg; range: 0.017-19.6mg/kg). The average fumonisin content of the 7 dried vine fruit samples which were found to be contaminated by potential fumonisin producing black Aspergilli was 7.22mg/kg (range: 4.55-35.49mg/kg). The isolates produced several fumonisin isomers also present in the dried vine fruit samples, including fumonisins B1-4, 3-epi-FB3, 3-epi-FB4, iso-FB1, and two iso-FB2,3 forms. Fumonisin B1 was detected for the first time in A. niger cultures. Most of these isomers have previously only been identified in Fusarium species. Our data indicate that A. niger and A. awamori are responsible for fumonisin contamination of dried vine fruits worldwide. The observed levels of contamination are alarming and pose a new threat for food safety. © 2010 Elsevier B.V. Source

Csernetics A.,University of Szeged | Nagy G.,University of Szeged | Iturriaga E.A.,University of Salamanca | Szekeres A.,FumoPrep Ltd. | And 3 more authors.
Fungal Genetics and Biology

The zygomycete Mucor circinelloides accumulates β-carotene as the main carotenoid compound. In this study, the applicability of some early genes of the general isoprenoid pathway to improve the carotenoid production in this fungus was examined. The isopentenyl pyrophosphate isomerase gene (ipi) was cloned and used together with the genes encoding farnesyl pyrophosphate synthase (isoA) and geranylgeranyl pyrophosphate synthase (carG) in overexpression studies. Transformation experiments showed that the first bottleneck in the pathway, from the aspect of carotenoid production, is the step controlled by the carG gene, but overexpression of the ipi and isoA genes also contributes to the availability of the precursors. Transformations with these isoprenoid genes in combination with a bacterial β-carotene ketolase gene yielded Mucor strains producing canthaxanthin and echinenone. © 2011 Elsevier Inc. Source

Szekeres A.,FumoPrep Ltd. | Szekeres A.,University of Szeged | Lorantfy L.,FumoPrep Ltd. | Lorantfy L.,Eotvos Lorand University | And 5 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment

Fumonisin B1 (FB1) is a highly toxic mycotoxin produced by fungal strains belonging to the Fusarium genus, which can be found mainly in maize products, and is gaining interest in food safety. To produce large amounts of pure FB1, a novel purifying method was developed by using centrifugal partition chromatography, which is a prominent member of the liquid-liquid chromatographic techniques. Rice cultured with Fusarium verticillioides was extracted with a mixture of methanol/water and found to contain 0.87 mg of FB1 per gram. The crude extracts were purified on a strong anion-exchange column and then separated by using a biphasic solvent system consisting of methyl-tert-butyl-ether-acetonitrile-0.1% formic acid in water. The collected fractions were analysed by flow injection-mass spectrometry and high-performance liquid chromatography coupled with Corona-charged aerosol detector and identified by congruent retention time on high-performance liquid chromatography and mass spectrometric data. This method produced approximately 120 mg of FB1 with a purity of more than 98% from 200 g of the rice culture. The whole purification process is able to produce a large amount of pure FB1 for analytical applications or for toxicological studies. © 2013 Copyright Taylor and Francis Group, LLC. Source

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