Arable Weeds at the Edges of Kettle Holes as Overwintering Habitat for Phytopathogenic Fungi

Weeds in agricultural landscapes can serve as alternate hosts for phytopathogenic fungi and promote the spatial and long-term distribution of these fungi. Especially, semi-natural habitats such as kettle holes are considered as a source of fungal pathogens because they are a permanent habitat for various weed species in arable lands. In our study, we investigated the suitability of nine different weed species and families at the edges of 18 kettle holes in two consecutive autumn/winter seasons as alternate hosts for Fusarium and Alternaria. We detected a fungal infestation with both genera on every weed species investigated with significantly higher abundances of these fungi in the second, notably wetter season. Eight weed species were described as non-host plants for Fusarium and Alternaria in agricultural landscapes in Brandenburg, Germany for the first time. In both autumn/winter periods, weeds harbored more Alternaria than Fusarium. The study revealed a high Fusarium species diversity in weeds and a community structure of up to 12 Fusarium species at the edges of kettle holes. Grasses showed the highest diversity and often the highest fungal abundances compared to herbaceous plants. Therefore, these habitats in arable lands can act as ecosystem disservice and promote the spread of fungal diseases in the surrounding crop fields.Peer Reviewe

Antagonistic Potential of Fluorescent Pseudomonads Colonizing Wheat Heads Against Mycotoxin Producing Alternaria and Fusaria

Natural control of phytopathogenic microorganisms is assumed as a priority function of the commensal plant microbiota. In this study, the suitability of fluorescent pseudomonads in the phyllosphere of crop plants as natural control agents was evaluated. Under field conditions, ears of winter wheat were found to be colonized with high consistency and at a high density by pseudomonads at the late milk dough stage. Isolates of these bacteria were evaluated for their potential to protect the plants from phytopathogenic Alternaria and Fusarium fungi. More Pseudomonas isolates were antagonistically active against alternaria than against fusaria in the dual culture test. The alternaria responded species-specifically and more sensitively to bacterial antagonism than the strain-specific reacting fusaria. A total of 110 randomly selected Pseudomonas isolates were screened for genes involved in the biosynthesis of the antibiotics 2,4-diacetylphloroglucinol, phenazine-1-carboxylic acid, pyoluteorin, and pyrrolnitrin. The key gene for production of the phloroglucinol was found in none of these isolates. At least one of the genes, encoding the biosynthesis of the other antibiotics was detected in 81% of the isolates tested. However, the antagonistic effect found in the dual culture assay was not necessarily associated with the presence of these antibiotic genes. Wheat grains as natural substrate were inoculated with selected antagonistic Pseudomonas isolates and Alternaria and Fusarium strains, respectively. The fungal growth was only slightly delayed, but the mycotoxin production was significantly reduced in most of these approaches. In conclusion, the distribution of phytopathogenic fungi of the genera Alternaria and Fusarium in the field is unlikely to be inhibited by naturally occurring pseudomonads, also because the bacterial antagonists were not evenly distributed in the field. However, pseudomonads can reduce the production of Alternaria and Fusarium mycotoxins in wheat grains and thus have the potential to improve the crop quality

The Effect of Biochars and Endophytic Bacteria on Growth and Root Rot Disease Incidence of Fusarium Infested Narrow-Leafed Lupin (Lupinus angustifolius L.)

The effects of biochar on plant growth vary depending on the applied biochar type, study site environmental conditions, microbial species, and plant–microbial interactions. The objectives of the present study were therefore to assess 1) the response of growth parameters of lupin and root disease incidence to the application of three biochar types in a loamy sandy soil, and 2) the role of endophytic bacteria in biological control of root rot disease incidence in lupin after the amendment of soil with different biochar types. As biochar types we tested (i) hydrochar (HTC) from maize silage, (ii) pyrolysis char from maize (MBC), and (iii) pyrolysis char from wood (WBC) at three different concentrations (1%, 2%, and 3% of char as soil amendments). There were no significant effects in lupin shoot and root growth in soils amended with WBC at any of the concentrations. MBC did not affect plant growth except for root dry weight at 2% MBC. HTC char at 2% concentration, significantly increased the root dry weight of lupin by 54–75%, and shoot dry weight by 21–25%. Lupin plants grown in soil amended with 2% and 3% WBC and MBC chars showed 40–50% and 10–20% disease symptoms, respectively. Plants grown in soil without biochar and with HTC char were healthy, and no disease incidence occurred. Pseudomonas putida L2 and Stenotrophomonas pavanii L8 isolates demonstrated a disease reduction compared to un-inoculated plants under MBC and WBC amended soil that was infested with Fusarium solani.Chinese Academy of SciencesPeer Reviewe

Root uptake and metabolization of Alternaria toxins by winter wheat plants using a hydroponic system

Fungi of the genus Alternaria are ubiquitous in the environment. Their mycotoxins can leach out of contaminated plants or crop debris into the soil entering the plant via the roots. We aim to evaluate the importance of this entry pathway and its contribution to the overall content of Alternaria toxins (ATs) in wheat plants to better understand the soil–plant-phytopathogen system. A hydroponic cultivation system was established and wheat plants were cultivated for up to two weeks under optimal climate conditions. One half of the plants was treated with a nutrient solution spiked with alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA), whereas the other half of the plants was cultivated without mycotoxins. Plants were harvested after 1 and 2 weeks and analyzed using a QuEChERS-based extraction and an in-house validated LC–MS/MS method for quantification of the ATs in roots, crowns, and leaves separately. ATs were taken up by the roots and transported throughout the plant up to the leaves after 1 as well as 2 weeks of cultivation with the roots showing the highest ATs levels followed by the crowns and the leaves. In addition, numerous AOH and AME conjugates like glucosides, malonyl glucosides, sulfates, and di/trihexosides were detected in different plant compartments and identified by high-resolution mass spectrometry. This is the first study demonstrating the uptake of ATs in vivo using a hydroponic system and whole wheat plants examining both the distribution of ATs within the plant compartments and the modification of ATs by the wheat plants

Chemotaxonomy of Mycotoxigenic Small-Spored Alternaria Fungi – Do Multitoxin Mixtures Act as an Indicator for Species Differentiation?

Necrotrophic as well as saprophytic small-spored Alternaria (A.) species are annually responsible for major losses of agricultural products, such as cereal crops, associated with the contamination of food and feedstuff with potential health-endangering Alternaria toxins. Knowledge of the metabolic capabilities of different species-groups to form mycotoxins is of importance for a reliable risk assessment. 93 Alternaria strains belonging to the four species groups Alternaria tenuissima, A. arborescens, A. alternata, and A. infectoria were isolated from winter wheat kernels harvested from fields in Germany and Russia and incubated under equal conditions. Chemical analysis by means of an HPLC-MS/MS multi-Alternaria-toxin-method showed that 95% of all strains were able to form at least one of the targeted 17 non-host specific Alternaria toxins. Simultaneous production of up to 15 (modified) Alternaria toxins by members of the A. tenuissima, A. arborescens, A. alternata species-groups and up to seven toxins by A. infectoria strains was demonstrated. Overall tenuazonic acid was the most extensively formed mycotoxin followed by alternariol and alternariol mono methylether, whereas altertoxin I was the most frequently detected toxin. Sulfoconjugated modifications of alternariol, alternariol mono methylether, altenuisol and altenuene were frequently determined. Unknown perylene quinone derivatives were additionally detected. Strains of the species-group A. infectoria could be segregated from strains of the other three species-groups due to significantly lower toxin levels and the specific production of infectopyrone. Apart from infectopyrone, alterperylenol was also frequently produced by 95% of the A. infectoria strains. Neither by the concentration nor by the composition of the targeted Alternaria toxins a differentiation between the species-groups A. alternata, A. tenuissima and A. arborescens was possible

CXCR4/CXCL12 Participate in Extravasation of Metastasizing Breast Cancer Cells within the Liver in a Rat Model

INTRODUCTION: Organ-specific composition of extracellular matrix proteins (ECM) is a determinant of metastatic host organ involvement. The chemokine CXCL12 and its receptor CXCR4 play important roles in the colonization of human breast cancer cells to their metastatic target organs. In this study, we investigated the effects of chemokine stimulation on adhesion and migration of different human breast cancer cell lines in vivo and in vitro with particular focus on the liver as a major metastatic site in breast cancer. METHODS: Time lapse microscopy, in vitro adhesion and migration assays were performed under CXCL12 stimulation. Activation of small GTPases showed chemokine receptor signalling dependence from ECM components. The initial events of hepatic colonisation of MDA-MB-231 and MDA-MB-468 cells were investigated by intravital microscopy of the liver in a rat model and under shRNA inhibition of CXCR4. RESULTS: In vitro, stimulation with CXCL12 induced increased chemotactic cell motility (p,0.05). This effect was dependent on adhesive substrates (type I collagen, fibronectin and laminin) and induced different responses in small GTPases, such as RhoA and Rac-1 activation, and changes in cell morphology. In addition, binding to various ECM components caused redistribution of chemokine receptors at tumour cell surfaces. In vivo, blocking CXCR4 decreased extravasation of highly metastatic MDA-MB-231 cells (p < 0.05), but initial cell adhesion within the liver sinusoids was not affected. In contrast, the less metastatic MDA-MB-468 cells showed reduced cell adhesion but similar migration within the hepatic microcirculation. CONCLUSION: Chemokine-induced extravasation of breast cancer cells along specific ECM components appears to be an important regulator but not a rate-limiting factor of their metastatic organ colonization.Claudia Wendel, André Hemping-Bovenkerk, Julia Krasnyanska, Sören Torge Mees, Marina Kochetkova, Sandra Stoeppeler and Jörg Haie

Nucleation and crystallization in bio-based immiscible polyester blends

Bio-based thermoplastic polyesters are highly promising materials as they combine interesting thermal and physical properties and in many cases biodegradability. However, sometimes the best property balance can only be achieved by blending in order to improve barrier properties, biodegradability or mechanical properties. Nucleation, crystallization and morphology are key factors that can dominate all these properties in crystallizable biobased polyesters. Therefore, their understanding, prediction and tailoring is essential. In this work, after a brief introduction about immiscible polymer blends, we summarize the crystallization behavior of the most important bio-based (and immiscible) polyester blends, considering examples of double-crystalline components. Even though in some specific blends (e.g., polylactide/polycaprolactone) many efforts have been made to understand the influence of blending on the nucleation, crystallization and morphology of the parent components, there are still many points that have yet to be understood. In the case of other immiscible polyester blends systems, the literature is scarce, opening up opportunities in this environmentally important research topic.The authors would like to acknowledge funding by the BIODEST project ((RISE) H2020-MSCA-RISE-2017-778092

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Party rules, party resources, and the politics of parliamentary democracies: how parties organize in the 21st Century

This article introduces the first findings of the Political Party Database (PPDB) project, a major survey of party organizations in parliamentary and semi-presidential democracies. The project’s first round of data covers 122 parties in 19 countries. In this paper we describe the scope of the database, then investigate what it tells us about contemporary party organization in these countries, focussing on parties’ resources, structures and internal decision-making. We examine organizational patterns by country and party family, and where possible we make temporal comparisons with older datasets. Our analyses suggest a remarkable coexistence of uniformity and diversity. In terms of the major organizational resources on which parties can draw, such as members, staff and finance, the new evidence largely confirms the continuation of trends identified in previous research: i.e., declining membership, but enhanced financial resources and more paid staff. We also find remarkable uniformity regarding the core architecture of party organizations. At the same time, however, we find substantial variation between countries and party families in terms of their internal processes, with particular regard to how internally democratic they are, and in the forms that this democratization takes