Fusarium toxins and total fungal biomass indicators in naturally contaminated wheat samples from north-eastern Poland in 2003.

Concentrations of fungal metabolites were measured in 32 wheat grain samples from north-eastern Poland in 2003. The samples originated from fields cultivated conventionally (but varying in chemical protection level) or cultivated organically. Concentrations of Fusarium toxins (HT-2, DON, 3-AcDON, NIV), trichodiene, microbial biomass indicators (fungal ergosterol and general adenosine 5'-triphosphate (ATP)) and seed vigour were assessed. A large variation between samples was observed, depending on their origin. Seed from organic farms contained similar amounts of Fusarium toxins but more ergosterol and ATP than conventionally grown and chemically protected seed. The highest levels of toxins and ergosterol were detected in samples from conventional cultivation lacking chemical protection. Intensive agronomic practices (including complete chemical protection) significantly lowered the levels of ergosterol, ATP and trichodiene, as compared with other cultivation systems.

Scanning electron microscopy of Fusarium damaged kernels of spring wheat.

Kernels of five wheat cultivars (Triticum aestivum) of different bread-making quality were examined. Grown under field conditions, heads of wheat were inoculated in the flowering stage with an aqueous suspension of Fusarium culmorum conidia. Wheat heads were collected from the control and inoculated plots at full maturity. Control (non-inoculated) kernels without any symptoms of disease and Fusarium damaged kernels (FDK) were examined under scanning electron microscopy (SEM). Examination of the FDK fraction confirmed localisation of Fusarium hyphae on the surface and inside the tissues of kernels. Observations of the endosperm from Fusarium infected kernels revealed presence of fungal hyphae in the endosperm and some characteristic structural changes in many of its regions, such as partial or complete lack of the protein matrix, damage to large and small starch granules caused by fungal amylolytic enzymes, disappearance of small starch granules as the colonisation progressed, complete disappearance of the starchy endosperm under severe infection. Fungal colonisation of the endosperm and structural changes in its area were highly variable traits within the FDK fraction of a given cultivar.

Antifungal biflavones from Cupressocyparis leylandii.

From the leaves of Cupressocyparis leylandii (Cupressaceae) cupressuflavone, 4-O-methylcupressuflavone, amentoflavone, 7-O-methylamentoflavone, 4-O-methylamentoflavone and hinokiflavone were isolated. 1H- and 13C-NMR data for 4-O-methylcupressuflavone are given for the first time. The biflavones from cultivar varieties of C. leylandii (Naylor's Blue, Castlewellan Gold) were chromatographicaly (HPLC) compared. The antifungal activity of cupressuflavone and 4-O-methylcupressuflavone against Alternaria alternata, Cladosporium oxysporum, Fusarium culmorum and F. avenaceum was assayed.

The similarity of antigenic proteins ofFusarium nivale (Fr.) Ces isolates.

The degree of similarity among dissolvable in water proteins obtained from 10Fusarium nivale isolates was studied. Tandem crossed Immunoelectrophoresis method was applied. Two immunological antisera: anti-F. nivale 4 and anti-F. nivale 15 were used in the investigation. Their homologous reactions resulted in 13 and 12 precipitation bands, respectively. The results allow to divide the isolates into three groups, according to their protein composition.

The estimation op physiological variability of some isolates of Fusarium nivale /Fr./ Ces.

The extend of physiological variability of five Isolates of Fusarium nivale /Fr./ Ces. using a tandem - crossed Immunoelectrophoresis was studied. In the homological reaction of antiserum antl-F. nivale fourteen precipiration lines were obtained. The variability of antigens originated from different isolates was found. The studied isolates showed differentiation In pathogenicity to three rye genotypes.