Möglichkeiten zur Qualitätssicherung ökologisch erzeugter Gartenbauprodukte durch Koordinierung der Wertschöpfungsketten

Die Untersuchungen konzentrieren sich auf den besonderen Aspekt der Qualitätserhaltung ökologischer Produkte in der Nacherntephase entlang der gesamten Wertschöpfungskette. Die hier geschätzten Verluste von über 1/3 der Erntemengen können zu einem beträchtlichen Teil auf unorganisiertes, unkoordiniertes und dadurch wenig produktangepasstes Handeln der beteiligten Akteure zurückgeführt werden. Mittels qualitativer Interviews wurden Akteure typischer Lieferketten in Deutschland und ergänzend dazu auch in der Schweiz und den Niederlanden zu ihren Aktivitäten zum Qualitätserhalt befragt. Als besondere Schwachstellen konnten die verschiedenen Qualitätsbilder der Akteure, mangelhafte technische Ressourcen, wenig aufeinander abgestimmte Arbeitsabläufe sowie ungenügende Nachfrage durch den Verbraucher identifiziert werden. Lösungsansätze ergeben sich aus einer verstärkter Kommunikation und Absprache aller Marktbeteiligten, qualifizierten Mitarbeiter auf allen Ebenen, einer gemeinsamen Orientierung der Arbeitsabläufe an den Bedürfnissen eines lebendigen und stoffwechselnden Produktes inklusive der Sicherung einer geschlossenen Kühlkette. Als notwendig erachtet werden verstärkt Anstrengungen zur Förderung der Nachfrage. Schweizerische Erfolgsfaktoren sind die eindeutige Positionierung und das Engagement des LEH sowie Strukturen, die ein weitgehend ausgeglichenes Kräfteverhältnis der Kettenakteure und damit einen konstruktiven Dialog ermöglichen. Als besonderer Vorteil der niederländischen Strukturen wird die traditionell professionelle Produktion sowie auch hier das allseitige Bemühen um Dialog und Austausch angesehen

(Epi)genetic Inheritance in Schistosoma mansoni: A Systems Approach

International audienceThe G×E concept, in which genotype × environment interactions bring about the phenotype, is widely used to describe biological phenomena. We propose to extend the initial notion of the concept, replacing G by ‘inheritance system’. This system, comprised of both genome and epigenome components, collectively interacts with the environment to shape the development of a phenotype. In the case of the human blood fluke Schistosoma mansoni, responsible for intestinal bilharzia, the phenotypic trait that is most relevant to global health is infection success. Taking a systems biology view we show how genetic and epigenetic interactions result in ephemeral, but also heritable, phenotypic variations that are important for infection success

DISMISS: detection of stranded methylation in MeDIP-Seq data

BACKGROUND: DNA methylation is an important regulator of gene expression and chromatin structure. Methylated DNA immunoprecipitation sequencing (MeDIP-Seq) is commonly used to identify regions of DNA methylation in eukaryotic genomes. Within MeDIP-Seq libraries, methylated cytosines can be found in both double-stranded (symmetric) and single-stranded (asymmetric) genomic contexts. While symmetric CG methylation has been relatively well-studied, asymmetric methylation in any dinucleotide context has received less attention. Importantly, no currently available software for processing MeDIP-Seq reads is able to resolve these strand-specific DNA methylation signals. Here we introduce DISMISS, a new software package that detects strand-associated DNA methylation from existing MeDIP-Seq analyses. RESULTS: Using MeDIP-Seq datasets derived from Apis mellifera (honeybee), an invertebrate species that contains more asymmetric- than symmetric- DNA methylation, we demonstrate that DISMISS can identify strand-specific DNA methylation signals with similar accuracy as bisulfite sequencing (BS-Seq; single nucleotide resolution methodology). Specifically, DISMISS is able to confidently predict where DNA methylation predominates (plus or minus DNA strands – asymmetric DNA methylation; plus and minus DNA stands – symmetric DNA methylation) in MeDIP-Seq datasets derived from A. mellifera samples. When compared to DNA methylation data derived from BS-Seq analysis of A. mellifera worker larva, DISMISS-mediated identification of strand-specific methylated cytosines is 80 % accurate. Furthermore, DISMISS can correctly (p <0.0001) detect the origin (sense vs antisense DNA strands) of DNA methylation at splice site junctions in A. mellifera MeDIP-Seq datasets with a precision close to BS-Seq analysis. Finally, DISMISS-mediated identification of DNA methylation signals associated with upstream, exonic, intronic and downstream genomic loci from A. mellifera MeDIP-Seq datasets outperforms MACS2 (Model-based Analysis of ChIP-Seq2; a commonly used MeDIP-Seq analysis software) and closely approaches the results achieved by BS-Seq. CONCLUSIONS: While asymmetric DNA methylation is increasingly being found in growing numbers of eukaryotic species and is the predominant pattern observed in some invertebrate genomes, it has been difficult to detect in MeDIP-Seq datasets using existing software. DISMISS now enables more sensitive examinations of MeDIP-Seq datasets and will be especially useful for the study of genomes containing either low levels of DNA methylation or for genomes containing relatively high amounts of asymmetric methylation

Methyl-CpG-binding (SmMBD2/3) and chromobox (SmCBX) proteins are required for neoblast proliferation and oviposition in the parasitic blood fluke Schistosoma mansoni

<div><p>While schistosomiasis remains a significant health problem in low to middle income countries, it also represents a recently recognised threat to more economically-developed regions. Until a vaccine is developed, this neglected infectious disease is primarily controlled by praziquantel, a drug with a currently unknown mechanism of action. By further elucidating how <i>Schistosoma</i> molecular components cooperate to regulate parasite developmental processes, next generation targets will be identified. Here, we continue our studies on schistosome epigenetic participants and characterise the function of a DNA methylation reader, the <i>Schistosoma mansoni</i> methyl-CpG-binding domain protein (SmMBD2/3). Firstly, we demonstrate that SmMBD2/3 contains amino acid features essential for 5-methyl cytosine (5mC) binding and illustrate that adult schistosome nuclear extracts (females > males) contain this activity. We subsequently show that SmMBD2/3 translocates into nuclear compartments of transfected murine NIH-3T3 fibroblasts and recombinant SmMBD2/3 exhibits 5mC binding activity. Secondly, using a yeast-two hybrid (Y2H) screen, we show that SmMBD2/3 interacts with the chromo shadow domain (CSD) of an epigenetic adaptor, <i>S</i>. <i>mansoni</i> chromobox protein (SmCBX). Moreover, fluorescent <i>in situ</i> hybridisation (FISH) mediated co-localisation of <i>Smmbd2/3</i> and <i>Smcbx</i> to mesenchymal cells as well as somatic- and reproductive- stem cells confirms the Y2H results and demonstrates that these interacting partners are ubiquitously expressed and found within both differentiated as well as proliferating cells. Finally, using RNA interference, we reveal that depletion of <i>Smmbd2/3</i> or <i>Smcbx</i> in adult females leads to significant reductions (46–58%) in the number of proliferating somatic stem cells (PSCs or neoblasts) as well as in the quantity of <i>in vitro</i> laid eggs. Collectively, these results further expand upon the schistosome components involved in epigenetic processes and suggest that pharmacological inhibition of SmMBD2/3 and/or SmCBX biology could prove useful in the development of future schistosomiasis control strategies.</p></div

Characterisation of serum IgG(T) responses to potential diagnostic antigens for equine cyathostominosis

Cyathostomins are ubiquitous parasitic nematodes of horses. These worms spend substantial periods as intestinal wall stage encysted larvae, which can comprise up to 90% of the total burden. Several million larvae have been reported in individuals. Emergence of these larvae from the gut wall can lead to life-threatening colitis. Faecal egg count tests, increasingly used by horse owners to inform anthelmintic treatments, do not correlate with the intra-host burden of cyathostomins; this represents a key gap in the diagnostic toolbox. Previously, a cyathostomin Gut Associated Larval Antigen was identified as a promising marker for the intra-host stages of infection. Here, cyathostomin Gut Associated Larval Antigen and an additional protein, Cyathostomin Immuno-diagnostic antigen, were investigated to examine their value in providing information on cyathostomin burden. ELISA analyses examined serum IgG(T) responses to recombinant proteins derived from individual cyathostomin species. Receiver Operator Characteristic curve analysis was performed on the ELISA data; proteins with the highest Area Under the Curve values were selected to test protein combinations to investigate which were the most informative in identifying the infection status of individuals. Three cocktail combinations were tested, comprising: (a) Cy-GALA proteins from two species and a Cy-CID protein from a third species (CT3), (b) Cy-GALA proteins from five species (CT5), and (c) all CT5 components, plus a Cy-CID protein from an additional species (CT6). The best predictive values for infection were obtained using CT3 and CT6, with similar values achieved for both. Proteins in CT3 are derived from the most commonly reported species, Cyathostomum catinatum, Cylicocyclus nassatus and Cylicostephanus longibursatus. This combination was selected for future development since it represents a more commercially viable format for a diagnostic test

The anti-fecundity effect of 5-azacytidine (5-AzaC) on Schistosoma mansoni is linked to dis-regulated transcription, translation and stem cell activities

Uncontrolled host immunological reactions directed against tissue-trapped eggs precipitate a potentially lethal, pathological cascade responsible for schistosomiasis. Blocking schistosome egg production, therefore, presents a strategy for simultaneously reducing immunopathology as well as limiting disease transmission in endemic or emerging areas. We recently demonstrated that the ribonucleoside analogue 5-azacytidine (5-AzaC) inhibited Schistosoma mansoni oviposition, egg maturation and ovarian development. While these anti-fecundity effects were associated with a loss of DNA methylation, other molecular processes affected by 5-AzaC were not examined at the time. By comparing the transcriptomes of 5-AzaC-treated females to controls, we provide evidence that this ribonucleoside analogue also modulates other crucial aspects of schistosome egg-laying biology. For example, S. mansoni gene products associated with amino acid-, carbohydrate-, fatty acid-, nucleotide- and tricarboxylic acid (TCA)- homeostasis are all dysregulated in 5-AzaC treated females. To validate the metabolic pathway most significantly affected by 5-AzaC, amino acid metabolism, nascent protein synthesis was subsequently quantified in adult schistosomes. Here, 5-AzaC inhibited this process by 68% ?16.7% (SEM) in male- and 81% ?4.8% (SEM) in female-schistosomes. Furthermore, the transcriptome data indicated that adult female stem cells were also affected by 5-AzaC. For instance, 40% of transcripts associated with proliferating schistosome cells were significantly down-regulated by 5-AzaC. This finding correlated with a considerable reduction (95%) in the number of 5-ethynyl-2?-deoxyuridine (EdU) positive cells found in 5-AzaC-treated females. In addition to protein coding genes, the effect that 5-AzaC had on repetitive element expression was also assessed. Here, 46 repeats were found differentially transcribed between 5-AzaC-treated and control females with long terminal repeat (LTR) and DNA transposon classes being amongst the most significant. This study demonstrates that the anti-fecundity activity of 5-AzaC affects more than just DNA methylation in schistosome parasites. Further characterisation of these processes may reveal novel targets for schistosomiasis controlauthorsversionPeer reviewe

The repositioning of epigenetic probes/inhibitors identifies new anti-schistosomal lead compounds and chemotherapeutic targets

Article Authors Metrics Comments Media Coverage Peer Review Abstract Author summary Introduction Materials and methods Results and discussion Supporting information Acknowledgments References Reader Comments (0) Media Coverage (0) Figures Abstract Background Praziquantel represents the frontline chemotherapy used to treat schistosomiasis, a neglected tropical disease (NTD) caused by infection with macro-parasitic blood fluke schistosomes. While this drug is safe, its inability to kill all schistosome lifecycle stages within the human host often requires repeat treatments. This limitation, amongst others, has led to the search for novel anti-schistosome replacement or combinatorial chemotherapies. Here, we describe a repositioning strategy to assess the anthelmintic activity of epigenetic probes/inhibitors obtained from the Structural Genomics Consortium. Methodology/Principle findings Thirty-seven epigenetic probes/inhibitors targeting histone readers, writers and erasers were initially screened against Schistosoma mansoni schistosomula using the high-throughput Roboworm platform. At 10 μM, 14 of these 37 compounds (38%) negatively affected schistosomula motility and phenotype after 72 hours of continuous co-incubation. Subsequent dose-response titrations against schistosomula and adult worms revealed epigenetic probes targeting one reader (NVS-CECR2-1), one writer (LLY-507 and BAY-598) and one eraser (GSK-J4) to be particularly active. As LLY-507/BAY-598 (SMYD2 histone methyltransferase inhibitors) and GSK-J4 (a JMJD3 histone demethylase inhibitor) regulate an epigenetic process (protein methylation) known to be critical for schistosome development, further characterisation of these compounds/putative targets was performed. RNA interference (RNAi) of one putative LLY-507/BAY-598 S. mansoni target (Smp_000700) in adult worms replicated the compound-mediated motility and egg production defects. Furthermore, H3K36me2, a known product catalysed by SMYD2 activity, was also reduced by LLY-507 (25%), BAY-598 (23%) and siSmp_000700 (15%) treatment of adult worms. Oviposition and packaging of vitelline cells into in vitro laid eggs was also significantly affected by GSK-J4 (putative cell permeable prodrug inhibitor of Smp_034000), but not by the related structural analogue GSK-J1 (cell impermeable inhibitor). Conclusion/Significance Collectively, these results provide further support for the development of next-generation drugs targeting schistosome epigenetic pathway components. In particular, the progression of histone methylation/demethylation modulators presents a tractable strategy for anti-schistosomal control

Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes

BACKGROUND: The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. RESULTS: Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and ‘Turbellaria’) contain methylated cytosines within their genome compartments. CONCLUSIONS: Collectively, these findings provide the first direct evidence for a functionally conserved and enzymatically active DNA methylation system throughout the Platyhelminthes. Defining how this epigenetic feature shapes phenotypic diversity and development within the phylum represents an exciting new area of metazoan biology

Transplantation of schistosome sporocysts between host snails::A video guide

Schistosomiasis is an important parasitic disease, touching roughly 200 million people worldwide. The causative agents are different Schistosoma species. Schistosomes have a complex life cycle, with a freshwater snail as intermediate host. After infection, sporocysts develop inside the snail host and give rise to human dwelling larvae. We present here a detailed step-by-step video instruction in English, French, Spanish and Portuguese that shows how these sporocysts can be manipulated and transferred from one snail to another. This procedure provides a technical basis for different types of ex vivo modifications, such as those used in functional genomics studies