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The occurrence of Ochratoxin A (OTA) in wine is commonly known, but there is only limited information about its occurrence in grape mash and wines of German origin. Climate change has led to higher temperatures in the southern regions of Germany, which may increase the growth of fungi associated with the production of OTA and increase the content of this mycotoxin in grapes. A safe and rapid UHPLC-FLD method was developed and validated to assess the contamination of grape mash and wine with OTA. A total of 71 samples of grape mash and 30 wines from various wine producers in Baden-Württemberg, Germany, were analysed for OTA content. The results showed that no samples contained OTA in concentrations above the limit of detection. Further monitoring of samples from different vintages is needed., (© 2024. The Author(s) under exclusive licence to Society for Mycotoxin (Research Gesellschaft für Mykotoxinforschung e.V.) and Springer-Verlag GmbH Germany, part of Springer Nature.)

Alley cropping systems (ACS) are regarded as a sustainable land-use alternative that provides ecosystem services, assuming that beneficial tree effects extend towards crop alleys. However, the spatial range of these effects has rarely been considered. The objective of this study was to investigate soil quality indicators at different distances from trees in three German silvo-arable ACS. We analysed soil microbial biomass C and N, ergosterol, microbial activity (enzyme activities, substrate-induced respiration rates) and their functional diversity (MicroResp™ method) in topsoils. Furthermore, fungal abundance and fungal and bacterial contribution to microbial residues (amino sugars) were determined. Tree effects on soil quality indicators were estimated for each depth, for the first time considering both, spatial dependence and abiotic factors (pH, clay content) using mixed effects models with repeated measures. Additionally, differences between soil depths were tested. Analysis combining the three ACS revealed a generalisation of effect sizes and spatial range of tree effects on soil quality indicators. Tree implementation in arable systems increased SOC, microbial biomass and activity in upper topsoils and shifted the composition of main microbial groups towards a higher fungal abundance and functional diversity. Soil quality indices decreased with increasing depth. However, in alleys, no differences between distances from trees were observed. Results demonstrate that ACS are capable to enhance soil quality mediated by microorganisms under trees within 5-8 years. Long-term studies are required to estimate whether beneficial tree effects extend towards crop alleys and deeper soil layers when systems are mature. [ABSTRACT FROM AUTHOR]

Abstract: Fusarium graminearum is the most important pathogen causing Fusarium head blight (FHB) of small cereal grains worldwide responsible for quantitative and qualitative yield losses. The presence in crops is often associated with mycotoxin contamination of foodstuff limiting its use for human and animal consumption. A collection of isolates of F. graminearum from Germany was characterized genetically and chemically for their potential to produce the B trichothecenes deoxynivalenol (DON) and nivalenol (NIV). Molecular methods with eight PCR assays were implemented based on functional Tri7 and Tri13 genes and on the tri5–tri6 intergenic region to differentiate between chemotaxonomic groups DON and NIV, resulting in a marked majority (61/63) of DON chemotypes. Mycotoxins produced on rice kernels were quantified by means of LC-MSMS including DON, NIV, 3-acetyl-DON (3-ADON), 15-acetyl-DON (15-ADON), DON-3-glucoside, fusarenon X, as well as zearalenone; all of them proving to be present in high concentration among the isolates. All DON-chemotype isolates also produced lower amounts of NIV with the amount being positively correlated (R²=0.89) to the DON amount. 15-ADON and 3-ADON are reported to be produced simultaneously by the isolates, the former dominating over the latter in all but one isolate. Fungal biomass, was quantified via ergosterol amount on rice. It was used to calculate specific mycotoxin production per biomass of isolates, ranging from 0.104 to 1.815mg DON mg-1 ergosterol, presenting a Gaussian distribution. Genotype and phenotype characterization revealed discrepancies with respect to mycotoxin production potential of the fungi, i.e. isolates from one chemotype were able to produce mycotoxins from other chemotypes in considerable amounts. [Copyright &y& Elsevier]

Abstract: High N availability resulting from anthropogenic emissions can alter the activities of enzymes involved in the breakdown of organic compounds in ecosystems. In a spruce forest stand in Solling, central Germany, the nitrogen contained in throughfall water was adjusted to pre-industrial concentrations and resprinkled as “clean rain” onto the forest floor. Soil was sampled from the clean rain and control plot at three different dates and four horizons. We investigated the response of active microbial biomass (SIR) and fungal biomass (ergosterol content) and 15 enzymes to the reduction of N deposition. Some N-cycling enzymes (urease, arginine deaminase, alanyl aminopeptidase, lysyl-alanyl aminopeptidase) showed increased activities whereas others (N-acetyl-glucosaminidase, protease, leucyl aminopeptidase, alanyl-alanyl-phenyl aminopeptidase) decreased under reduced N treatment indicating a modification of the reaction rates of different enzymes involved in N cycling. For the C- and P-cycling enzymes, α- and β-glucosidase as well as phosphatase activities increased in the clean rain treatment in spring 2006 in Oe and Oa horizons, respectively, but did not affect the pattern of substrate decomposition. Spatial variability of microbial biomass and enzyme activities within the soil profile indicated that the decrease in microbial activity with depth was driven by resource allocation. [Copyright &y& Elsevier]

Contrary to streams, decomposition processes of terrestrial leaf litter are still poorly understood in lakes. Here, we examined the decomposition of two leaf species, beech ( Fagus sylvatica) and poplar ( Populus nigra ‘ italica’) in the littoral zone of a large pre-alpine lake at a wave exposed site. We focussed on the shredding impact of benthic invertebrates in a field experiment and on the effects of wave-induced disturbances under field and mesocosm conditions. In contrast to our expectations, benthic shredders did not reveal an important role in leaf processing under the conditions of the field experiment (early spring time, wave impact zone). Strong wave turbulence during storm events significantly reduced leaf mass, FPOM and invertebrate densities at field conditions. Several reasons can explain the low importance of shredders in our field study: (a) phenology of the shredder species, (b) feeding preferences and alternative food sources for gammarids, (c) generally low abundance of the native gammarid species due to the recent occurrence of an invasive predator, (d) disturbance of shredder activity due to high wave impact and (e) relatively low food value of the offered leaves. We suggest that leaf litter decomposition in lakes occurs in specific process domains, which largely depend on the hydraulic characteristics and on water-level fluctuations. [ABSTRACT FROM AUTHOR]