236 research outputs found

    The mutualistic fungus Piriformospora indica protects barley roots from a loss of antioxidant capacity caused by the necrotrophic pathogen Fusarium culmorum

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    Fusarium culmorum causes root rot in barley (Hordeum vulgare), resulting in severely reduced plant growth and yield. Pretreatment of roots with chlamydospores of the mutualistic root-colonizing basidiomycete Piriformospora indica (Agaricomycotina) prevented necrotization of root tissues and plant growth retardation commonly associated with Fusarium root rot. Quantification of Fusarium infections with a real-time PCR assay revealed a correlation between root rot symptoms and the relative amount of fungal DNA. Fusarium-infected roots showed reduced levels of ascorbate and glutathione (GSH), along with reduced activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). Consistent with this, Fusarium-infected roots showed elevated levels of lipid hydroperoxides and decreased ratios of reduced to oxidized forms of ascorbate and glutathione. In clear contrast, roots treated with P. indica prior to inoculation with F. culmorum showed levels of ascorbate and GSH that were similar to controls. Likewise, lipid peroxidation and the overall reduction in antioxidant enzyme activities were largely attenuated by P. indica in roots challenged by F. culmorum. These results suggest that P. indica protects roots from necrotrophic pathogens at least partly, through activating the plant’s antioxidant capacity

    The abundance of endofungal bacterium Rhizobium radiobacter (syn. Agrobacterium tumefaciens) increases in its fungal host Piriformospora indica during the tripartite sebacinalean symbiosis with higher plants

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    Rhizobium radiobacter (syn. Agrobacterium tumefaciens, syn. "Agrobacterium fabrum") is an endofungal bacterium of the fungal mutualist Piriformospora (syn. Serendipita) indica (Basidiomycota), which together form a tripartite Sebacinalean symbiosis with a broad range of plants. R. radiobacter strain F4 (RrF4), isolated from P. indica DSM 11827, induces growth promotion and systemic resistance in cereal crops, including barley and wheat, suggesting that R. radiobacter contributes to a successful symbiosis. Here, we studied the impact of endobacteria on the morphology and the beneficial activity of P. indica during interactions with plants. Low numbers of endobacteria were detected in the axenically grown P. indica (long term lab-cultured, lcPiri) whereas mycelia colonizing the plant root contained increased numbers of bacteria. Higher numbers of endobacteria were also found in axenic cultures of P. indica that was freshly re-isolated (riPiri) from plant roots, though numbers dropped during repeated axenic re-cultivation. Prolonged treatments of P. indica cultures with various antibiotics could not completely eliminate the bacterium, though the number of detectable endobacteria decreased significantly, resulting in partial-cured P. indica (pcPiri). pcPiri showed reduced growth in axenic cultures and poor sporulation. Consistent with this, pcPiri also showed reduced plant growth promotion and reduced systemic resistance against powdery mildew infection as compared with riPiri and lcPiri. These results are consistent with the assumption that the endobacterium R. radiobacter improves P. indica's fitness and thus contributes to the success of the tripartite Sebacinalean symbiosis

    Untersuchungen des BÖL-Verbundprojektes zur Kupferminimierung im ökologischen Weinbau

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    The development of sustainable and economically feasible strategies to get an effec-tual control of downy mildew on grapes (Plasmopara viticola) with less than 3 kg/(ha*a) of copper to avoid further environmental risks is the intention of this project. Due to harmful effects on the natural environment, copper applications are under considera-tion. Therefore, in this four-year-project first of all test products are screened under greenhouse conditions on potted vines. Thereafter the best test agents are studied in organically managed test vineyards. Finally the selected strategies are tested under practical conditions on organically managed vineyards. Beyond these examinations a close link between wineries and research is given by SME and consultant partners. The results indicate that plant extracts, finely ground stones and new copper formula-tions could probably serve as plant resistance improvers and plant protection prod-ucts, respectively, to prevent attacks of P. viticola. Moreover, it was possible to select prosperous agents and strategies for the growing period 2007. These were agents of the substance categories “new copper formulations”, “plant extracts” and “finely ground stones”. Regarding the results of three growing periods, the project will provide effective and economically feasible alternatives for copper applications in order to deliver sustainable approaches for P. viticola control in practise

    Vascular architecture and hypoxic profiles in human head and neck squamous cell carcinomas

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    Tumour oxygenation and vasculature are determinants for radiation treatment outcome and prognosis in patients with squamous cell carcinomas of the head and neck. In this study we visualized and quantified these factors which may provide a predictive tool for new treatments. Twenty-one patients with stage III–IV squamous cell carcinomas of the head and neck were intravenously injected with pimonidazole, a bioreductive hypoxic marker. Tumour biopsies were taken 2 h later. Frozen tissue sections were stained for vessels and hypoxia by fluorescent immunohistochemistry. Twenty-two sections of biopsies of different head and neck sites were scanned and analysed with a computerized image analysis system. The hypoxic fractions varied from 0.02 to 0.29 and were independent from T- and N-classification, localization and differentiation grade. No significant correlation between hypoxic fraction and vascular density was observed. As a first attempt to categorize tumours based on their hypoxic profile, three different hypoxia patterns are described. The first category comprised tumours with large hypoxic, but viable, areas at distances even greater than 200 μm from the vessels. The second category showed a typical band-like distribution of hypoxia at an intermediate distance (50–200 μm) from the vessels with necrosis at greater distances. The third category demonstrated hypoxia already within 50 μm from the vessels, suggestive for acute hypoxia. This method of multiparameter analysis proved to be clinically feasible. The information on architectural patterns and the differences that exist between tumours can improve our understanding of the tumour micro-environment and may in the future be of assistance with the selection of (oxygenation modifying) treatment strategies. © 2000 Cancer Research Campaig

    Duurzame aanpak van plagen in de handel : duurzame bestrijding van plaaginsecten en plant parasitaire nematoden in de keten van internationale handel in plantmaterialen

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    Quarantaine organismen leveren cruciale problemen op in de internationale handel. Ondanks strikte maatregelen en controle worden insecten- en nematodenplagen regelmatig door toenemende internationale handel overgebracht naar niet besmette gebieden. Quarantaine plagen veroorzaken grote economische verliezen en leiden tot handelsbelemmeringen. Sommige kleine insecten zoals trips en witte vliegen of nematoden zijn moeilijk te bestrijden met pesticiden. Fumigatie met ontsmettingsmiddelen was een veel toegepaste methode om quarantaine plagen te bestrijden middels een pre-shipment behandeling. Een van de meest effectieve ontsmettingsmiddelen methylbromide (MeBr) is sinds 2010 niet meer toegelaten in Nederlands vanwege het chadelijke effect op de ozonlaag. Een effectief en milieuvriendelijk alternatief voor MeBr is zeer gewenst. Controlled atmosphere temperature treatment (CATT) is een fysieke behandelingsmethode en heeft een aantoonbaar dodelijk effect op diverse insecten- en nematodenplagen. De CATT methode is een combinatie van lucht en temperatuur over een bepaalde tijdsduur om plagen maximaal af te doden met een minimaal of acceptabel fytotoxisch effect op plantproducten. Dit is een milieuvriendelijke methode en heeft daardoor geen toelating nodig voor toepassing

    Ethylene supports colonization of plant roots by the mutualistic fungus Piriformospora indica

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    The mutualistic basidiomycete Piriformospora indica colonizes roots of mono- and dicotyledonous plants, and thereby improves plant health and yield. Given the capability of P. indica to colonize a broad range of hosts, it must be anticipated that the fungus has evolved efficient strategies to overcome plant immunity and to establish a proper environment for nutrient acquisition and reproduction. Global gene expression studies in barley identified various ethylene synthesis and signaling components that were differentially regulated in P. indica-colonized roots. Based on these findings we examined the impact of ethylene in the symbiotic association. The data presented here suggest that P. indica induces ethylene synthesis in barley and Arabidopsis roots during colonization. Moreover, impaired ethylene signaling resulted in reduced root colonization, Arabidopsis mutants exhibiting constitutive ethylene signaling, -synthesis or ethylene-related defense were hyper-susceptible to P. indica. Our data suggest that ethylene signaling is required for symbiotic root colonization by P. indica

    The fitness of dispersing spotted hyaena sons is influenced by maternal social status

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    Life history theory predicts that mothers should provide their offspring with a privileged upbringing if this enhances their offspring's and their own fitness. In many mammals, high-ranking mothers provide their offspring with a privileged upbringing. Whether dispersing sons gain fitness benefits during adulthood from such privileges (a 'silver spoon' effect) has rarely been examined. In this paper, we show that in the complex, female-dominated society of spotted hyaenas, high-born sons grew at higher rates, were more likely to disperse to clans offering the best fitness prospects, started reproducing earlier and had a higher reproductive value than did lower-born sons. This illustrates the evolutionary importance of maternal effects even in societies in which male size or fighting ability does not influence fitness. By demonstrating for the first time in a non-human mammal that maternal status influences immigration patterns, the study also advances our understanding of two key ecological and evolutionary processes, dispersal and habitat selection

    Preventing crime in cooperation with the mental health care profession

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    Although major mental disorders do not have a central position in many criminological theories, there seems to be an evident relationship between these disorders and criminal behavior. In daily practice police officers and mental health care workers work jointly to prevent nuisance and crime and to keep the city livable. Examining the situations where the criminal justice system and mental health institutes are jointly involved to prevent crime, some pitfalls emerge that seem to threaten successful cooperation. There appear to be unrealistic expectations of the possibility to reduce the risk of reoffending by means of treatment and of the possibility to predict which offender poses a risk to society. Another complexity is the fact that both parties work from different backgrounds and pursue different goals. The way society and the criminal justice system deal with persons who are assumed to be a risk to the community because of a mental disorder demands a further investigation from a criminological perspective

    Soluble Beta-Amyloid Precursor Protein Is Related to Disease Progression in Amyotrophic Lateral Sclerosis

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    Background: Biomarkers of disease progression in amyotrophic lateral sclerosis (ALS) could support the identification of beneficial drugs in clinical trials. We aimed to test whether soluble fragments of beta-amyloid precursor protein (sAPPa and sAPPß) correlated with clinical subtypes of ALS and were of prognostic value. Methodology/Principal Findings: In a cross-sectional study including patients with ALS (N = 68) with clinical follow-up data over 6 months, Parkinson’s disease (PD, N = 20), and age-matched controls (N = 40), cerebrospinal fluid (CSF) levels of sAPPa a, sAPPß and neurofilaments (NfH SMI35) were measured by multiplex assay, Progranulin by ELISA. CSF sAPPa and sAPPß levels were lower in ALS with a rapidly-progressive disease course (p = 0.03, and p = 0.02) and with longer disease duration (p = 0.01 and p = 0.01, respectively). CSF NfH SMI35 was elevated in ALS compared to PD and controls, with highest concentrations found in patients with rapid disease progression (p,0.01). High CSF NfH SMI3 was linked to low CSF sAPPa and sAPPß (p = 0.001, and p = 0.007, respectively). The ratios CSF NfH SMI35 /CSF sAPPa,-ß were elevated in patients with fast progression of disease (p = 0.002 each). CSF Progranulin decreased with ongoing disease (p = 0.04). Conclusions: This study provides new CSF candidate markers associated with progression of disease in ALS. The data suggest that a deficiency of cellular neuroprotective mechanisms (decrease of sAPP) is linked to progressive neuro-axona
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