Performance of Winter Wheat Cultivars Grown Organically and Conventionally with Focus on Fusarium Head Blight and Fusarium Trichothecene Toxins.

Growing acreage and changing consumer preferences cause increasing interest in the cereal products originating from organic farming. Lack of results of objective test, however, does not allow drawing conclusions about the effects of cultivation in the organic system and comparison to currently preferred conventional system. Field experiment was conducted in organic and conventional fields. Thirty modern cultivars of winter wheat were sown. They were characterized for disease infection including Fusarium head blight, seed sowing value, the amount of DNA of the six species of Fusarium fungi as well as concentration of ergosterol and trichothecenes in grain. The intensity Fusarium head blight was at a similar level in both systems. However, Fusarium colonization of kernels expressed as ergosterol level or DNA concentration was higher for the organic system. It did not reflect in an increased accumulation of trichothecenes in grain, which was similar in both systems, but sowing value of organically produced seeds was lower. Significant differences between analyzed cropping systems and experimental variants were found. The selection of the individual cultivars for organic growing in terms of resistance to diseases and contamination of grain with Fusarium toxins was possible. Effects of organic growing differ significantly from the conventional and grain obtained such way can be recommended to consumers. There are indications for use of particular cultivars bred for conventional agriculture in the case of organic farming, and the growing organic decreases plant stress resulting from intense fertilization and chemical plant protection.

Phenolic acids in cereal grain: Occurrence, biosynthesis, metabolism and role in living organisms.

Studies on plant metabolism, including those on cereals, increasingly focus on plant phenolic compounds, e.g. phenolic acids and flavonoids. The aim of this study was to present a comprehensive picture of major phenolic acids in grain, starting from their biosynthesis, their occurrence and finally their role in the vegetation of cereals. It is clearly connected with the polygenic plant resistance to pathogens, particularly toxin-forming fungi. Other crucial aspects include the transformations that take place during the technological processing of grain, their metabolic pathway in the human organism as well as the presentation of the health-promoting effect of grain processing products containing phenolic acids. These compounds are used as precursors of bioactive compounds commonly applied both for therapeutic purposes and in the cosmetics, engineering and food industries. An advantage of phenolic acids is the fact that they may be metabolized by microorganisms found in nature and thus they provide an alternative to the increasing load of man-made chemicals in the environment.

Resistance-Related l-Pyroglutamic Acid Affects the Biosynthesis of Trichothecenes and Phenylpropanoids by F. graminearum Sensu Stricto.

Fungicide application remains amongst the most widely used methods of fungal control in agroecosystems. However, the extensive use of fungicides poses hazards to human health and the natural environment and does not always ensure the effective decrease of mycotoxins in food and feed. Nowadays, the rising threat from mycotoxin contamination of staple foods has stimulated efforts in developing alternative strategies to control plant pathogenic fungi. A substantial effort is focused on the identification of plant-derived compounds inhibiting mycotoxin production by plant pathogenic fungi. l-Pyroglutamic acid has recently been suggested as playing a role in the response of barley to toxigenic Fusaria. Considering the above, we studied the response of various strains of F. graminearum sensu stricto to different levels of l-pyroglutamic acid on solid YES (yeast extract sucrose) media. l-Pyroglutamic acid decreased the accumulation of trichothecenes in all examined strains. Gene expression studies addressing Tri genes (Tri4, Tri5, and Tri10), which induce the biosynthesis of trichothecenes, revealed the production of mycotoxins by l-pyroglutamic acid to be inhibited at the transcriptional level. Besides inhibitory effects on mycotoxin production, l-pyroglutamic acid exhibited variable and concentration-related effects on phenylpropanoid production by fungi. Accumulation of most of the fungal-derived phenolic acids decreased in the presence of 100 and 400 µg/g of l-pyroglutamic acid. However, a higher dose (800 µg/g) of l-pyroglutamic acid increased the accumulation of trans-cinnamic acid in the media. The accumulation of fungal-derived naringenin increased in the presence of l-pyroglutamic acid. Contrasting results were obtained for quercetin, apigenin, luteolin, and kaempferol, the accumulation of which decreased in the samples treated with 100 and 400 µg/g of l-pyroglutamic acid, whereas the highest l-pyroglutamic acid concentration (800 µg/g) seemed to induce their biosynthesis. The results obtained in this study provide new insights for breeders involved in studies on resistance against Fusaria.

Development of a Highly Sensitive FcMito qPCR Assay for the Quantification of the Toxigenic Fungal Plant Pathogen Fusarium culmorum.

Fusarium culmorum is a ubiquitous, soil-borne fungus (ascomycete) causing foot and root rot and Fusarium head blight on cereals. It is responsible for yield and quality losses as well as grain contamination with mycotoxins, which are a potential health hazard. An extremely sensitive mitochondrial-based qPCR assay (FcMito qPCR) for quantification of F. culmorum was developed in this study. To provide specificity, the FcMito assay was successfully validated against 85 F. culmorum strains and 53 isolates of 30 other fungal species. The assay efficiency and sensitivity were evaluated against different F. culmorum strains with various amounts of pure fungal DNA and in the presence of background wheat DNA. The results demonstrated the high efficiency of the assay (97.2⁻106.0%, R²-values > 0.99). It was also shown that, in the presence of background DNA, 0.01 pg of fungal template could be reliably quantified. The FcMito assay was used to quantify F. culmorum DNA using 108 grain samples with different trichothecene levels. A significant positive correlation was found between fungal DNA quantity and the total trichothecene content. The obtained results showed that the sensitivity of the FcMito assay was much higher than the nuclear-based qPCR assay for F. culmorum.

Changes in Phenylpropanoid and Trichothecene Production by Fusarium culmorum and F. graminearum Sensu Stricto via Exposure to Flavonoids.

Flavonoids are a group of hydroxylated polyphenolic compounds widely distributed in the plant kingdom. Biosynthesis of these compounds involves type III PKSs, whose presence has been recently predicted in some fungal species through genome sequencing efforts. In this study, for the first time it was found that Fusaria produce flavonoids on solid YES medium. Naringenin, as the central precursor of all flavonoids, was produced at highest quantities, followed by quercetin, kaempferol, apigenin and luteolin. In plants, flavonoids are involved in the protection of cereals to a wide range of stresses, including host defense against Fusaria. Under in vitro conditions, strains of Fusarium culmorum and F. graminearum sensu stricto were incubated at levels of flavonoids close to amounts produced by cereals in response to fungal infection. The amounts of exogenous naringenin, apigenin, luteolin, kaempferol and quercetin were reduced and converted by fungi to the other flavonoid derivatives. Treatment of fungi with naringenin derivatives led to the inhibition of naringenin production. Correspondingly, the production of fungal-derived phenolic acids decreased in flavonoid treated samples, although this effect appeared to be dependent on the strain, flavonoid molecule and its concentration. Fusaria showed high variability in trichothecene production in response to flavonoids. With emphasis on quercetin, mycotoxin accumulation in the media was significantly decreased by luteolin, kaempferol, naringenin and apigenin. However, in some cases, apigenin led to the increase of mycotoxin content in the media. Gene expression experiments of Tri genes responsible for trichothecene biosynthesis (Tri4, Tri5 and Tri10) proved that the inhibition of mycotoxin production by flavonoids occurred at the transcriptional level. However, the changes in Tri transcript levels were not significant in most apigenin and all kaempferol-treated cultures. In this study, a link was established between antioxidant and antiradical properties of flavonoids and their effects on fungi.

Sinapic Acid Affects Phenolic and Trichothecene Profiles of F. culmorum and F. graminearum Sensu Stricto.

Plant-derived compounds for reducing the mycotoxin load in food and feed have become a rapidly developing research field of importance for plant breeding efforts and in the search for natural fungicides. In this study, toxigenic strains of Fusarium culmorum and F. graminearum sensu stricto were exposed to sinapic acid on solid YES media at levels close to those reported in wheat bran. Fusaria produced phenolic acids, whose accumulation was decreased by exogenous sinapic acid. Strains exposed to the lowest doses of sinapic acid showed more efficient reduction of phenolic acid production than fungi kept at higher concentrations of this compound. Fungi reduced exogenous sinapic acid, leading to the formation of syringic aldehyde. Treatment with sinapic acid led to a dramatic accumulation of its parent compound ferulic acid, presumably due to inhibition of the further conversion of this phenolic compound. Exogenous sinapic acid decreased the production of trichothecenes by fungi. Higher doses of sinapic acid resulted in more efficient reduction of mycotoxin accumulation in the media. Gene expression studies of Tri genes responsible for trichothecene biosynthesis (Tri4, Tri5 and Tri10) proved that the inhibition of mycotoxin production by sinapic acid occurred at the transcriptional level. Fusaria respond to sinapic acid by stimulation of ergosterol biosynthesis.

Contamination of pine and birch wood dust with microscopic fungi and determination of its sterol contents.

Wood compounds, especially sterols, are connected with the level of contamination with microscopic fungi. Within this study, tests were conducted on wood dust samples collected at various work stations in a pine and birch timber conversion plant. Their contamination with mycobiota was measured as the concentration of ergosterol (ERG) by ultra performance liquid chromatography (UPLC). Another aim of this study was to assess the effect of contamination with microscopic fungi on the sterol contents in wood dusts. Analyses were conducted on five sterols: desmosterol, cholesterol, lanosterol, stigmasterol, and ß-sitosterol using UPLC and their presence was confirmed using gas chromatography/mass spectrometry (GC/MS). The results of chemical analyses showed the greatest contamination with mycobiota in birch wood dust. We also observed varied contents of individual sterols depending on the wood dust type. Their highest concentration was detected in birch dust. The discriminant analysis covering all tested compounds as predictors showed complete separation of all tested wood dust types. The greatest discriminatory power was found for stigmasterol, desmosterol, and ergosterol.

trans-Cinnamic and Chlorogenic Acids Affect the Secondary Metabolic Profiles and Ergosterol Biosynthesis by Fusarium culmorum and F. graminearum Sensu Stricto.

Plant-derived compounds limiting mycotoxin contamination are currently of major interest in food and feed production. However, their potential application requires an evaluation of their effects on fungal secondary metabolism and membrane effects. In this study, different strains of Fusarium culmorum and F. graminearum sensu stricto were exposed to trans-cinnamic and chlorogenic acids on solid YES media. Fusaria produced phenolic acids, whose accumulation was lowered by exogenous phenolic compounds. In addition, fungi reduced exogenous phenolic acids, leading either to their conversion or degradation. trans-Cinnamic acid was converted to caffeic and ferulic acids, while chlorogenic acid was degraded to caffeic acid. The latter underwent further degradation to protocatechuic acid. Fungal-derived trans-cinnamic acid, as the first intermediate of the shikimate pathway, increased after chlorogenic acid treatment, presumably due to the further inhibition of the conversion of trans-cinnamic acid. Exogenous trans-cinnamic and chlorogenic acid displayed the inhibition of mycotoxin production by Fusaria, which appeared to be largely dependent on the phenolic compound and its concentration and the assayed strain. Exogenous phenolic acids showed different effects on ergosterol biosynthesis by fungi. It was found that the production of this membrane sterol was stimulated by trans-cinnamic acid, while chlorogenic acid negatively impacted ergosterol biosynthesis, suggesting that phenolic acids with stronger antifungal activities may upregulate ergosterol biosynthesis by Fusaria. This paper reports on the production of phenolic acids by Fusaria for the first time.

Level of contamination with mycobiota and contents of mycotoxins from the group of trichothecenes in grain of wheat , oats, barley, rye and triticale harvested in Poland in 2006- 2008.

INTRODUCTION AND OBJECTIVE: The risk of cereal exposure to microbial contamination is high and possible at any time, starting from the period of plant vegetation, through harvest, up to the processing, storage and transport of the final product. Contents of mycotoxins in grain are inseparably connected with the presence of fungal biomass, the presence of which may indicate the occurrence of a fungus, and indirectly also products of its metabolism. MATERIALS AND METHOD: Analyses were conducted on 378 grain samples of wheat, triticale, barley, rye and oats collected from grain silos located at grain purchase stations and at mills in Poland in 2006, 2007 and 2008. The concentrations of ERG and mycotoxins from the group of trichothecenes, as well as CFU numbers were analysed. RESULTS: The tested cereals were characterised by similarly low concentrations of both the investigated fungal metabolites and the level of microscopic fungi. However, conducted statistical analyses showed significant variation between tested treatments. Oat and rye grain contained the highest amounts of ERG, total toxins and CFU. In turn, the lowest values of investigated parameters were found in grain of wheat and triticale. CONCLUSIONS: Chemometric analyses, based on the results of chemical and microbiological tests, showed slight differences between contents of analysed metabolites between the years of the study, and do not confirm the observations on the significance of the effect of weather conditions on the development of mycobiota and production of mycotoxins; however, it does pertain to treatments showing no significant infestation. Highly significant correlations between contents of trichothecenes and ERG concentration (higher than in the case of the correlation of the total toxin concentrations/log cfu/g), indicate that the level of this metabolite is inseparably connected with mycotoxin contents in grain.

ToxGen: an improved reference database for the identification of type B-trichothecene genotypes in Fusarium.

Type B trichothecenes, which pose a serious hazard to consumer health, occur worldwide in grains. These mycotoxins are produced mainly by three different trichothecene genotypes/chemotypes: 3ADON (3-acetyldeoxynivalenol), 15ADON (15-acetyldeoxynivalenol) and NIV (nivalenol), named after these three major mycotoxin compounds. Correct identification of these genotypes is elementary for all studies relating to population surveys, fungal ecology and mycotoxicology. Trichothecene producers exhibit enormous strain-dependent chemical diversity, which may result in variation in levels of the genotype's determining toxin and in the production of low to high amounts of atypical compounds. New high-throughput DNA-sequencing technologies promise to boost the diagnostics of mycotoxin genotypes. However, this requires a reference database containing a satisfactory taxonomic sampling of sequences showing high correlation to actually produced chemotypes. We believe that one of the most pressing current challenges of such a database is the linking of molecular identification with chemical diversity of the strains, as well as other metadata. In this study, we use the Tri12 gene involved in mycotoxin biosynthesis for identification of Tri genotypes through sequence comparison. Tri12 sequences from a range of geographically diverse fungal strains comprising 22 Fusarium species were stored in the ToxGen database, which covers descriptive and up-to-date annotations such as indication on Tri genotype and chemotype of the strains, chemical diversity, information on trichothecene-inducing host, substrate or media, geographical locality, and most recent taxonomic affiliations. The present initiative bridges the gap between the demands of comprehensive studies on trichothecene producers and the existing nucleotide sequence databases, which lack toxicological and other auxiliary data. We invite researchers working in the fields of fungal taxonomy, epidemiology and mycotoxicology to join the freely available annotation effort.

Depicting the Discrepancy between Tri Genotype and Chemotype on the Basis of Strain CBS 139514 from a Field Population of F. graminearum Sensu Stricto from Argentina.

Recent studies on a field population of F. graminearum sensu stricto from Argentina revealed an atypical panel of strains identified through PCR genotyping as 15ADON genotypes, but producing high levels of 3ADON. Based on representative strain CBS 139514, we asked if the discrepancy between the trichothecene genotype and chemotype might result from an inter-chemotype recombination of the chemotype-determining genes. To answer this, we sequenced the complete core Tri gene cluster (around 30,200 bp) from this strain and compared its sequence to sequence data of typical type B trichothecene genotypes/chemotypes. Sequence alignment showed that CBS 139514 has an identical sequence within the entire core Tri cluster to the 15ADON genotype. The revealed discrepancy underlines the need for using both molecular and chemical methods for reliable characterization of toxigenic strains of Fusarium.

Comparison of Volatiles Profile and Contents of Trichothecenes Group B, Ergosterol, and ATP of Bread Wheat, Durum Wheat, and Triticale Grain Naturally Contaminated by Mycobiota.

In natural conditions cereals can be infested by pathogenic fungi. These can reduce the grain yield and quality by contamination with mycotoxins which are harmful for plants, animals, and humans. To date, performed studies of the compounds profile have allowed for the distinction of individual species of fungi. The aim of this study was to determine the profile of volatile compounds and trichothecenes of group B, ergosterol, adenosine triphosphate content carried out on a representative sample of 16 genotypes of related cereals: triticale, bread wheat, and durum wheat. Based on an analysis of volatile compounds by means of gas chromatography mass spectrometry and with the use of an electronic nose, volatile profiles for cereals were determined. Differentiation is presented at four levels through discriminant analysis, heatmaps, principal component analysis (PCA), and electronic nose maps. The statistical model was built by subsequent incorporation of chemical groups such as trichothecenes (GC/MS), fungal biomass indicators ergosterol (HPLC) and ATP (luminometric) and volatiles. The results of the discriminatory analyses showed that the volatile metabolites most markedly differentiated grain samples, among which were mainly: lilial, trichodiene, p-xylene. Electronic nose analysis made it possible to completely separate all the analyzed cereals based only on 100 ions from the 50-150 m/z range. The research carried out using chemometric analysis indicated significant differences in the volatile metabolites present in the grain of bread wheat, durum wheat and triticale. The end result of the performed analyses was a complete discrimination of the examined cereals based on the metabolites present in their grain.

Relationships between Genetic Diversity and Fusarium Toxin Profiles of Winter Wheat Cultivars.

Fusarium head blight is one of the most important and most common diseases of winter wheat. In order to better understanding this disease and to assess the correlations between different factors, 30 cultivars of this cereal were evaluated in a two-year period. Fusarium head blight resistance was evaluated and the concentration of trichothecene mycotoxins was analysed. Grain samples originated from plants inoculated with Fusarium culmorum and naturally infected with Fusarium species. The genetic distance between the tested cultivars was determined and data were analysed using multivariate data analysis methods. Genetic dissimilarity of wheat cultivars ranged between 0.06 and 0.78. They were grouped into three distinct groups after cluster analysis of genetic distance. Wheat cultivars differed in resistance to spike and kernel infection and in resistance to spread of Fusarium within a spike (type II). Only B trichothecenes (deoxynivalenol, 3-acetyldeoxynivalenol and nivalenol) produced by F. culmorum in grain samples from inoculated plots were present. In control samples trichothecenes of groups A (H-2 toxin, T-2 toxin, T-2 tetraol, T-2 triol, scirpentriol, diacetoxyscirpenol) and B were detected. On the basis of Fusarium head blight assessment and analysis of trichothecene concentration in the grain relationships between morphological characters, Fusarium head blight resistance and mycotoxins in grain of wheat cultivars were examined. The results were used to create of matrices of distance between cultivars - for trichothecene concentration in inoculated and naturally infected grain as well as for FHB resistance Correlations between genetic distance versus resistance/mycotoxin profiles were calculated using the Mantel test. A highly significant correlation between genetic distance and mycotoxin distance was found for the samples inoculated with Fusarium culmorum. Significant but weak relationships were found between genetic distance matrix and FHB resistance or trichothecene concentration in naturally infected grain matrices.

Development of an FgMito assay: A highly sensitive mitochondrial based qPCR assay for quantification of Fusarium graminearum sensu stricto.

An ascomycete fungus, Fusarium graminearum sensu stricto (s.s.), is the major cause of Fusarium head blight (FHB), a devastating disease of cereals worldwide. The fungus contaminates crops with mycotoxins, which pose a serious threat to food and feed safety. In this study, we developed a highly sensitive mitochondrial based qPCR assay (FgMito qPCR) for quantification of F. graminearum s.s. To ensure high sensitivity of the assay, primers and a Minor-groove binding (MGB) probe were designed based on multi-copy mitochondrial DNA. The FgMito assay was successfully validated against a range of geographically diverse F. graminearum s.s. strains to ensure uniformity of the assay at an intraspecific level, as well as with other fungal species to ensure specificity. The assay was further evaluated in terms of efficiency and sensitivity against a test panel of different F. graminearum s.s. strains with various levels of pure fungal DNA and in the presence of wheat background DNA. The results showed a high efficiency of the assay developed, ranging from 93% to 101% with r(2)-values of >0.99. We further showed that three low concentrations of fungal template 2 pg, 0.6 pg and 0.2 pg could be reliably quantified in the presence of wheat background DNA. The FgMito assay was used to quantify F. graminearum s.s. DNA on 65 field samples from a range of hosts with defined levels of trichothecenes. We revealed a significant positive correlation between fungal DNA quantity and the sum of trichothecenes. Lastly, we showed a higher sensitivity of the FgMito assay than the nuclear based qPCR assay for F. graminearum s.s. by comparing Ct-values from both assays.

Contamination of wheat grain with microscopic fungi and their metabolites in Poland in 2006-2009.

Microscopic fungi are microorganisms commonly found in cereal products. Pathogens of cereals colonising kernels are responsible, among other things, for deterioration of the technological value of grain. However, the greatest threat is posed by mycotoxins produced by toxin-forming strains of these microorganisms. The aim of the present study was to determine the level of contamination with microscopic fungi and mycotoxins from the group of trichothecenes in wheat grain from Poland in a 4-year cycle. In the period 2006-2009, studies were conducted on the content of fungal metabolites (ergosterol [ERG] and type A and B trichothecenes) and the content of microscopic fungi expressed in colony-forming units (CFU) in wheat grain. A total of 129 grain samples were examined. Analysed wheat samples had similar contents of both the investigated fungal metabolites and levels of microscopic fungi. Contents of microscopic fungi were low. Concentration of ERG, on average, was 2.64 mg/kg, while in colony forming units this value ranged from 10(1) CFU/g to over 10(3) CFU/g. The total concentration of type A and B trichothecenes was also low and within the 4 years of the investigation did not exceed 0.062 mg/kg. Concentration of DON did not exceed 1,250 µg/kg, established as safe in grain for human consumption, in any of the tested samples. For the results collected in the years 2006-2009 and presented in this paper, correlations were calculated between the amount of mycoflora and analysed metabolites in 3 possible combinations: 0.7096 for ERG/total toxin concentration, 0.6086 for ERG/log CFU/g, and 0.4016 for the concentration of total toxins/log CFU/g. Highly significant correlations between the content of trichothecenes and the concentration of ERG indicate that the level of this metabolite is closely related to the content of mycotoxins in grain.

Quantitative volatile compound profiles in fungal cultures of three different Fusarium graminearum chemotypes.

Biosynthesis in fungal cultures of 27 Fusarium graminearum isolates of three different chemotypes (3AcDON, 15AcDON and NIV) grown on yeast extract sucrose agar medium was examined in this study. Volatile organic compound (VOC) analysis performed by headspace solid phase microextraction GC-MS allowed for determination of various concentrations of six alcohols, 14 aldehydes and ketones, 10 benzene derivatives, one furane, five hydrocarbons and three terpenes. In general, the determined VOC profile in fungal cultures was dominated by hexanal (up to 74%), followed by nonanal (18%) and 2-methylbutanal (18%). Principal component analysis and discriminant analysis based on VOCs allowed for unambiguous discrimination of all studied isolates into three different groups in accordance with their trichothecene production (chemotypes). Significant differences were revealed between the levels of aldehydes and ketones, benzene derivatives and hydrocarbons in fungal cultures of three F. graminearum chemotypes.

The fatty acid profile in different wheat cultivars depending on the level of contamination with microscopic fungi.

Analyses were conducted on 30 winter wheat samples growing under controlled conditions and following inoculation with fungi Fusarium culmorum. In inoculated samples the mean concentration of 30 analysed fatty acids was significantly higher in relation to the control and amounted to 1,396 mg/kg vs. 1,046 mg/kg in the control kernels. Recorded concentrations for individual cultivars were significantly correlated with the concentration of fungal biomass. Higher concentration in the control was recorded only for the acid trans C18:2n-6. It was also found that the acid profiles are characteristic of individual cultivars. Statistical analysis showed that trans C18:2n-6, C18:1, C18:3n-3 and C18:3n-6 were the acids with the greatest discriminatory power in distinguishing inoculated samples from the control. Discriminatory analysis separated individual cultivars into quality classes of winter wheat cultivars depending on the presence of a specific fatty acid profile.

The evaluation of microfungal contamination of dust created during woodworking in furniture factories.

BACKGROUND: Microscopic fungi are the biological agent of occupational risk in the woodworking environment. Microbiological and chemical methods were used for determination of their concentration and species composition in dust. MATERIAL AND METHODS: Dust was sampled in 3 factories producing furniture using different materials. The 1st factory (A) processes solid wood, the 2nd (B) - chipboards and the 3rd factory (C) uses both wood and wood composites. The samples were collected in 12 different workstations and locations in each factory. The quantitative content of fungal biomass was determined basing on analysis of ergosterol (ERG). The species composition of fungi was analyzed using the microbiological method basing on culture morphology. RESULTS: The concentration of ergosterol was relatively low and ranged from 0.012 mg/kg to 3.36 mg/kg. The average value of ERG amounted to 1.25 mg/kg in factories A and C and 1.15 mg/kg in factory B. The most frequently isolated fungi in factory A and B were Penicillum and Aspergillus. However, in the factory C, only Trichoderma was isolated. The maximum concentration of fungi in dust collected in factory B was 2377 cfu/g and it is 3 times more than in the dust from factories A and C. CONCLUSIONS: Workers of furniture factories may be exposed to airborne fungi associated with the wood dust posing health hazard. The content of these fungi is relatively small (ERG - max: 3.36 mg/kg) but the species, especially genera Penicillum and Aspergillus, found in the dust which were reported as having allergic and toxic properties.

Structural characterization of flavonoid glycosides from leaves of wheat (Triticum aestivum L.) using LC/MS/MS profiling of the target compounds.

The aim of this study was to present integrated mass spectrometric methods for the structural characterization and identification of flavonoid glycoconjugates. During the liquid chromatography/mass spectrometry analyses, TriVersa NanoMate chip-based system with nanoelectrospray ionization and fraction collection was combined to a quadrupole time-of-flight mass spectrometer. In the extract samples prepared from green leaves of wheat plantlets, 41 flavonoid derivatives were recognized. Part of the target natural products had the full structure being characterized after the registration of mass spectra, where m/z values for protonated [M + H](+) and deprotonated molecules [M - H](-) were annotated. MS(2) and pseudo-MS(3) experiments were performed for [M + H](+) or [M - H](-) and aglycone ions (Y0(+/-)-type), respectively. It should be underlined that pseudo-MS(3) mass spectra were registered for aglycone product ions in the mass spectra of O-glycosides present in the extract samples. In many cases, only tentative structural identification of aglycones was possible, mainly because of the presence of numerous C-monoglycoside or C-diglycoside in the samples. Acylation of the sugar moiety and/or methylation of the aglycone in the flavonoid glycosides under study was observed. The existence of isobaric and/or isomeric compounds was demonstrated in the extract studied. The collision-induced dissociation mass spectra registered for C,O-diglycosides and C,C-diglycosides did not permit to draw complete structural conclusions about the compounds studied. For the investigated class of natural products, unambiguous classification of sugar moieties linked to the aglycones from the recorded mass spectra was not possible. Registration of the positive and negative ion mass spectra did not lead to the precise conclusion about the glycosylation position at C-6 or C-8, and O-4' or O-7 atoms. It was possible, on the basis of the collected MS(2) spectra, to differentiate between O-glycosides and C-glycosides present in the samples analyzed.

Sublethal concentrations of azoles induce tri transcript levels and trichothecene production in Fusarium graminearum.

The effect of sublethal concentrations (below the recommended field doses) of propiconazole and tebuconazole on the amount of tri transcripts and accumulation of trichothecenes by three Fusarium graminearum isolates of 3ADON, 15ADON, and NIV chemotypes was examined on yeast extract sucrose agar (YES) medium. RT-qPCR analyses showed higher tri4, tri5, and tri11 transcript levels in cultures of all three F. graminearum isolates supplemented with sublethal concentrations of azoles as compared to those in nontreated control, although the fold changes in the amount of tri transcripts differed according to the type of azole used. Mycotoxin analysis revealed higher increase in trichothecene accumulation in most of the tebuconazole-treated samples of all chemotypes tested. A huge increase in all trichothecene compounds was revealed in samples of all F. graminearum isolates treated with 5 mg L(-1) of tebuconazole. An inducing effect of azoles on trichothecene accumulation in the grain was confirmed in an in planta experiment; however, the results obtained were inconsistent. A higher amount of trichothecenes and fungal DNA was quantitated in two grain samples treated with sublethal propiconazole concentrations. In contrast, no significant increase in trichothecene levels was revealed in grain samples treated with sublethal concentrations of tebuconazole.