A. Ritieni

Occurrence of Beauvericin and Enniatins in Wheat Affected by Fusarium avenaceum Head Blight

ABSTRACT We evaluated Fusarium contamination and the levels of hexadepsipeptide mycotoxins in 13 wheat samples affected by head blight in Finland. Fusarium avenaceum was the dominant species (91%) isolated from all samples, but isolates of F. culmorum (4%), F. tricinctum (3%), and F. poae (2%) also were recovered. Beauvericin (0.64 to 3.5 μg/g) was detected in all 13 samples. Enniatin B (trace to 4.8 μg/g) was detected in 12 samples, enniatin B1 (trace to 1.9 μg/g) was detected in 8 samples, and enniatin A1 (trace to 6.9 μg/g) was detected in 10 samples. Ten of 13 strains of F. avenaceum and 2 strains of F. poae and F. tricinctum produced beauvericin in culture on rice (trace to 70, 9.4, and 33 μg/g, respectively). All strains also produced enniatins (trace to 2,700 μg/g). This is the first report on the natural cooccurence of beauvericin and enniatins in wheat infected predominantly by F. avenaceum.

Apple polyphenol extracts prevent damage to human gastric epithelial cells in vitro and to rat gastric mucosa in vivo

Background: Fresh fruit and vegetables exert multiple biological effects on the gastrointestinal mucosa. Aim: To assess whether apple extracts counteract oxidative or indomethacin induced damage to gastric epithelial cells in vitro and to rat gastric mucosa in vivo. Methods: Apple extracts were obtained from freeze dried apple flesh of the “Annurca” variety. Cell damage was induced by incubating MKN 28 cells with xanthine-xanthine oxidase or indomethacin and quantitated by MTT. In vivo gastric damage was induced by indomethacin 35 mg/kg. Intracellular antioxidant activity was determined using the (2,2′-azinobis (3-ethylbenzothiazolin-6-sulfonate) method. Malondialdehyde intracellular concentration, an index of lipid peroxidation, was determined by high pressure liquid chromatography with fluorometric detection. Results: (1) Apple extracts decreased xanthine-xanthine oxidase or indomethacin induced injury to gastric epithelial cells by 50%; (2) catechin or chlorogenic acid (the main phenolic components of apple extracts) were equally effective as apple extracts in preventing oxidative injury to gastric cells; and (3) apple extracts (i) caused a fourfold increase in intracellular antioxidant activity, (ii) prevented its decrease induced by xanthine-xanthine oxidase, (iii) counteracted xanthine-xanthine oxidase induced lipid peroxidation, and (iv) decreased indomethacin injury to the rat gastric mucosa by 40%. Conclusions: Apple extracts prevent exogenous damage to human gastric epithelial cells in vitro and to the rat gastric mucosa in vivo. This effect seems to be associated with the antioxidant activity of apple phenolic compounds. A diet rich in apple antioxidants might exert a beneficial effect in the prevention of gastric diseases related to generation of reactive oxygen species.

Moderate coffee consumption increases plasma glutathione but not homocysteine in healthy subjects.

Background : The consumption of unfiltered coffee, containing bioactive diterpenes, causes an increase in plasma homocysteine concentration. A slight increase in plasma homocysteine is also caused by large quantities of filtered coffee. Coffee terpenes also raise plasma glutathione in mice.

Beauvericin and fumonisin B1 in preharvest Fusarium moniliforme maize ear rot in Sardinia

Six selected samples of preharvest maize ear rot, from different localities in Sardinia, Italy, were examined for causal Fusarium species and associated mycotoxins. All samples were almost exclusively found to be affected by Fusarium moniliforme, which was isolated from all infected ear sample kernels (100%). In two samples, in addition to F. moniliforme, F. proliferatum was also present but in a reduced percentage of kernels (up to 42%). All samples were found to be contaminated by fumonisin B1 (up to 250 mg/kg). Four samples were also found to be contaminated by beauvericin (up to 10 mg/kg), with higher concentration in samples also infected by F. proliferatum. When cultured on autoclaved maize kernels for 4 weeks at 25 degrees C, all 13 strains of F. moniliforme examined produced fumonisin B1 (up to 3750 mg/kg), whereas only three strains also produced beauvericin, but in very low amounts (5 mg/kg). In the same assay, four isolates of F. proliferatum also produced high amounts of fumonisin B1 (up to 2500 mg/kg) but this was associated with higher concentrations of beauvericin (up to 175 mg/kg). This is the first indication of the production of beauvericin by F. moniliforme, as well as of its co-occurrence with fumonisin B1 in preharvest F. moniliforme maize ear rot.

The effects of cereal substrate and temperature on production of beauvericin, moniliformin and fusaproliferin by Fusarium subglutinans ITEM-1434

One strain of Fusarium subglutinans (ITEM-1434) isolated from maize ear rot in Poland was tested for the ability to synthesize moniliformin (MON), beauvericin (BEA) and fusaproliferin (FP) on six cereal substrates (wheat, rye, barley, oat, maize and rice kernels) for 3 weeks at 25 degrees C and on rice at three different temperatures (20, 25 and 30 degrees C). Most MON (497 micrograms/g) was produced on rice; most BEA (704 micrograms/g) on wheat or rice, and most FP (422 micrograms/g) on rye. When cultured on rice, F. subglutinans produced the highest levels of BEA and FP at 20-25 degrees C, while MON production was best at 30 degrees C.

Natural occurrence of fumonisin B2 in red wine from Italy.

The potential risk of exposure to fumonisin B2 (FB2) in the grape-wine chain has recently been revealed after a report of Aspergillus niger in grapes and its ability to produce FB2 and FB4. The occurrence of these two fumonisins in wine was investigated by LC/MS/MS in 51 market samples (45 red, five white and one rosé wine) produced in various Italian regions. Nine samples of red wine were found to be contaminated by fumonisin B2 at levels ranging from 0.4 to 2.4 ng/ml, while FB4 was not detected in any of the tested samples. This is the first report on the natural occurrence of FB2 in wine, indicating that, although at low levels, there is a potential risk of FB2 exposure for the wine-consumer.

Supercritical fluid extraction of Beauvericin from maize

Beauvericin (BEA), a supercritical fluid extraction with supercritical carbon dioxide from maize was investigated. Extraction efficiencies under several different extraction conditions were examined. Pressure, temperature, extraction time, organic modifier and water matrix content (10%) were investigated. The best extraction conditions were at a temperature of 60 degrees C, 3200psi, for 30min static extraction time and methanol as modifier solvent. Extraction recovery of 36% without modifier by adding water to the matrix in the extraction vessel (reproducibility relative standard deviations (R.S.D.)=3-5%) were recorded. Extraction recovery of 76.9% with methanol as co-solvent (reproducibility R.S.D.=3-5%) was obtained. Data shows that SFE gives a lower BEA recovery compared to conventional extraction protocol with organic solvents while SFE with modifier and conventional extraction yields are comparable. BEA extract contents were determined by high pressure liquid chromatography (HPLC) with a diode array detector (DAD) at 205nm and BEA peak confirmed by LC-MS. Acetonitrile-water as mobile phase and column C-18 were both tested. Instrumental and analytical parameters were optimized in the range linear interval from 1 to 500mgkg(-1) and reached a detection limit of 2ng.

An immunological approach to monitor protein lactosylation of heated food model systems

Abstract Poly-L-lysine, a high molecular weight synthetic compound with a large number of free amino groups, was glycated with lactose through the Maillard reaction (MR). Polyclonal mouse and rabbit antibodies (Abs) were obtained and characterised by competitive ELISA (enzyme-linked immuno assay), immunoblotting and cytofluorimetric assays. Results demonstrated that the Abs react specifically with lactosylated food proteins, i.e. bovine serum albumin (BSA) and casein and do not cross react with the underivatised proteins. The immunoreactivity between Abs and lactose-BSA adducts was strongly inhibited by N-ϵ-deoxy-lactulosyl-L-lysine, indicating that this typical MR product is recognised specifically by our Abs. These reagents can be a useful tool to monitor the MR reaction between carbohydrates and lysine, which occurs during the thermal treatment of food.

Dominance of Group 2 and fusaproliferin production by Fusarium subglutinans from Iowa maize

Fusarium subglutinans (teleomorph Gibberella subglutinans, member of the Gibberella fujikuroi complex) is an important toxigenic pathogen of maize. Recently, two cryptic species (Groups 1 and 2) have been described within F. subglutinans, but little is known about the occurrence of the two groups in North America or their relative capacities to produce mycotoxins. In this study, 58 F. subglutinans strains from kernels of maize grown in Iowa, USA, were evaluated for cryptic speciation and production of the mycotoxins fusaproliferin and beauvericin. Fifty-six of the 58 strains (97%) belonged to Group 2, and two strains belonged to Group 1, based on restricted fragment length polymorphisms derived from amplification of histone H3 and β-tubulin gene fragments. Fifty-four Group 2 strains and both Group 1 strains produced fusaproliferin at concentrations ranging from 12 to 3000 µg g–1 of solid maize culture. None of the F. subglutinans strains from Iowa produced beauvericin at detectable amounts, although most F. subglutinans strains from Europe and elsewhere are beauvericin producers. These results indicate that F. subglutinans strains infecting maize kernels in Iowa belong almost exclusively to Group 2 and that they have a high potential for fusaproliferin production; furthermore, the results confirm an association between Group 2 genotypes and lack of beauvericin production. This is the first report characterizing the phylogenetic groups of F. subglutinans occurring in Iowa; the predominance of Group 2 suggests that populations of the fungus in Iowa and Europe remain isolated from each other. Fusaproliferin contamination of grain appears to be a risk wherever F. subglutinans occurs, but beauvericin contamination from F. subglutinans is associated only with Group 1.