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Publikation

Bochnia, M.; Sander, J.; Ziegler, J.; Terhardt, M.; Sander, S.; Janzen, N.; Cavalleri, J.-M. V.; Zuraw, A.; Wensch-Dorendorf, M.; Zeyner, A.; Detection of MCPG metabolites in horses with atypical myopathy PLOS ONE 14, e0211698, (2019) DOI: 10.1371/journal.pone.0211698

Atypical myopathy (AM) in horses is caused by ingestion of seeds of the Acer species (Sapindaceae family). Methylenecyclopropylacetyl-CoA (MCPA-CoA), derived from hypoglycin A (HGA), is currently the only active toxin in Acer pseudoplatanus or Acer negundo seeds related to AM outbreaks. However, seeds or arils of various Sapindaceae (e.g., ackee, lychee, mamoncillo, longan fruit) also contain methylenecyclopropylglycine (MCPG), which is a structural analogue of HGA that can cause hypoglycaemic encephalopathy in humans. The active poison formed from MCPG is methylenecyclopropylformyl-CoA (MCPF-CoA). MCPF-CoA and MCPA-CoA strongly inhibit enzymes that participate in β-oxidation and energy production from fat. The aim of our study was to investigate if MCPG is involved in Acer seed poisoning in horses. MCPG, as well as glycine and carnitine conjugates (MCPF-glycine, MCPF-carnitine), were quantified using high-performance liquid chromatography-tandem mass spectrometry of serum and urine from horses that had ingested Acer pseudoplatanus seeds and developed typical AM symptoms. The results were compared to those of healthy control horses. For comparison, HGA and its glycine and carnitine derivatives were also measured. Additionally, to assess the degree of enzyme inhibition of β-oxidation, several acyl glycines and acyl carnitines were included in the analysis. In addition to HGA and the specific toxic metabolites (MCPA-carnitine and MCPA-glycine), MCPG, MCPF-glycine and MCPF-carnitine were detected in the serum and urine of affected horses. Strong inhibition of β-oxidation was demonstrated by elevated concentrations of all acyl glycines and carnitines, but the highest correlations were observed between MCPF-carnitine and isobutyryl-carnitine (r = 0.93) as well as between MCPA- (and MCPF-) glycine and valeryl-glycine with r = 0.96 (and r = 0.87). As shown here, for biochemical analysis of atypical myopathy of horses, it is necessary to take MCPG and the corresponding metabolites into consideration.
Publikation

Bochnia, M.; Scheidemann, W.; Ziegler, J.; Sander, J.; Vollstedt, S.; Glatter, M.; Janzen, N.; Terhardt, M.; Zeyner, A.; Predictive value of hypoglycin A and methylencyclopropylacetic acid conjugates in a horse with atypical myopathy in comparison to its cograzing partners Equine Vet. Educ. 30, 24-28, (2018) DOI: 10.1111/eve.12596

Hypoglycin A (HGA) was detected in blood and urine of a horse suffering from atypical myopathy (AM; Day 2, serum, 8290 μg/l; urine: Day 1, 574, Day 2, 742 μg/l) and in its cograzing partners with a high variability (46–1570 μg/l serum). Over the period of disease, the level of the toxic metabolites (methylencyclopropylacetic acid [MCPA]‐conjugates) increased in body fluids of the AM horse (MCPA‐carnitine: Day 2, 0.246, Day 3, 0.581 μmol/l serum; MCPA‐carnitine: Day 2, 0.621, Day 3, 0.884 μmol/mmol creatinine in urine) and HGA decreased rapidly (Day 3, 2430 μg/l serum). In cograzing horses MCPA‐conjugates were not detected. HGA in seeds ranged from 268 to 367 μg/g. Although HGA was present in body fluids of healthy cograzing horses, MCPA‐conjugates were not detectable, in contrast to the AM horse. Therefore, increasing concentrations of MCPA‐conjugates are supposed to be linked with the onset of AM and both parameters seem to indicate the clinical stage of disease. However, detection of HGA in body fluids of cograzing horses might be a promising step in preventing the disease.
Publikation

Krägeloh, T.; Cavalleri, J. M. V.; Ziegler, J.; Sander, J.; Terhardt, M.; Breves, G.; Cehak, A.; Identification of hypoglycin A binding adsorbents as potential preventive measures in co-grazers of atypical myopathy affected horses Equine Vet. J. 50, 220-227, (2018) DOI: 10.1111/evj.12723

BackgroundIntestinal absorption of hypoglycin A (HGA) and its metabolism are considered major prerequisites for atypical myopathy (AM). The increasing incidence and the high mortality rate of AM urgently necessitate new therapeutic and/or preventative approaches.ObjectivesTo identify a substance for oral administration capable of binding HGA in the intestinal lumen and effectively reducing the intestinal absorption of the toxin.Study designExperimental in vitro study.MethodsSubstances commonly used in equine practice (activated charcoal composition, di‐tri‐octahedral smectite, mineral oil and activated charcoal) were tested for their binding capacity for HGA using an in vitro incubation method. The substance most effective in binding HGA was subsequently tested for its potential to reduce intestinal HGA absorption. Jejunal tissues of 6 horses were incubated in Ussing chambers to determine mucosal uptake, tissue accumulation, and serosal release of HGA in the presence and absence of the target substance. Potential intestinal metabolism in methylenecyclopropyl acetic acid (MCPA)‐conjugates was investigated by analysing their concentrations in samples from the Ussing chambers.ResultsActivated charcoal composition and activated charcoal were identified as potent HGA binding substances with dose and pH dependent binding capacity. There was no evidence of intestinal HGA metabolism.Main limitationsBinding capacity of adsorbents was tested in vitro using aqueous solutions, and in vivo factors such as transit time and composition of intestinal content, may affect adsorption capacity after oral administration.ConclusionsFor the first time, this study identifies substances capable of reducing HGA intestinal absorption. This might have major implications as a preventive measure in cograzers of AM affected horses but also in horses at an early stage of intoxication.
Publikation

Ibañez, C.; Delker, C.; Martinez, C.; Bürstenbinder, K.; Janitza, P.; Lippmann, R.; Ludwig, W.; Sun, H.; James, G. V.; Klecker, M.; Grossjohann, A.; Schneeberger, K.; Prat, S.; Quint, M.; Brassinosteroids Dominate Hormonal Regulation of Plant Thermomorphogenesis via BZR1 Curr. Biol. 28, 303-310.e3, (2018) DOI: 10.1016/j.cub.2017.11.077

Thermomorphogenesis is defined as the suite of morphological changes that together are likely to contribute to adaptive growth acclimation to usually elevated ambient temperature [1, 2]. While many details of warmth-induced signal transduction are still elusive, parallels to light signaling recently became obvious (reviewed in [3]). It involves photoreceptors that can also sense changes in ambient temperature [3, 4, 5] and act, for example, by repressing protein activity of the central integrator of temperature information PHYTOCHROME-INTERACTING FACTOR 4 (PIF4 [6]). In addition, PIF4 transcript accumulation is tightly controlled by the evening complex member EARLY FLOWERING 3 [7, 8]. According to the current understanding, PIF4 activates growth-promoting genes directly but also via inducing auxin biosynthesis and signaling, resulting in cell elongation. Based on a mutagenesis screen in the model plant Arabidopsis thaliana for mutants with defects in temperature-induced hypocotyl elongation, we show here that both PIF4 and auxin function depend on brassinosteroids. Genetic and pharmacological analyses place brassinosteroids downstream of PIF4 and auxin. We found that brassinosteroids act via the transcription factor BRASSINAZOLE RESISTANT 1 (BZR1), which accumulates in the nucleus at high temperature, where it induces expression of growth-promoting genes. Furthermore, we show that at elevated temperature BZR1 binds to the promoter of PIF4, inducing its expression. These findings suggest that BZR1 functions in an amplifying feedforward loop involved in PIF4 activation. Although numerous negative regulators of PIF4 have been described, we identify BZR1 here as a true temperature-dependent positive regulator of PIF4, acting as a major growth coordinator.
Publikation

García, M. L.; Bó, E. D.; da Graça, J. V.; Gago-Zachert, S.; Hammond, J.; Moreno, P.; Natsuaki, T.; Pallás, V.; Navarro, J. A.; Reyes, C. A.; Luna, G. R.; Sasaya, T.; Tzanetakis, I. E.; Vaira, A. M.; Verbeek, M.; ICTV Report Consortium, .; Corrigendum: ICTV Virus Taxonomy Profile: Ophioviridae J. Gen. Virol. 99, 949-949, (2018) DOI: 10.1099/jgv.0.001093

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Publikation

Ibañez, C.; Poeschl, Y.; Peterson, T.; Bellstädt, J.; Denk, K.; Gogol-Döring, A.; Quint, M.; Delker, C.; Ambient temperature and genotype differentially affect developmental and phenotypic plasticity in Arabidopsis thaliana BMC Plant Biol. 17, 114, (2017) DOI: 10.1186/s12870-017-1068-5

BackgroundGlobal increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best.ResultsHere, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown under long day conditions in four different temperatures ranging from 16 to 28 °C. We used Q10, GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions.ConclusionGenotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.
Publikation

García, M. L.; Bó, E. D.; da Graça, J. V.; Gago-Zachert, S.; Hammond, J.; Moreno, P.; Natsuaki, T.; Pallás, V.; Navarro, J. A.; Reyes, C. A.; Luna, G. R.; Sasaya, T.; Tzanetakis, I. E.; Vaira, A. M.; Verbeek, M.; ICTV Report Consortium, .; ICTV Virus Taxonomy Profile: Ophioviridae J. Gen. Virol. 98, 1161-1162, (2017) DOI: 10.1099/jgv.0.000836

The Ophioviridae is a family of filamentous plant viruses, with single-stranded negative, and possibly ambisense, RNA genomes of 11.3–12.5 kb divided into 3–4 segments, each encapsidated separately. Virions are naked filamentous nucleocapsids, forming kinked circles of at least two different contour lengths. The sole genus, Ophiovirus, includes seven species. Four ophioviruses are soil-transmitted and their natural hosts include trees, shrubs, vegetables and bulbous or corm-forming ornamentals, both monocots and dicots. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Ophioviridae, which is available at http://www.ictv.global/report/ophioviridae.
Publikation

Gasperini, D.; Acosta, I. F.; Farmer, E. E.; Cotyledon Wounding of Arabidopsis Seedlings Bio Protoc. 6, e1712, (2016) DOI: 10.21769/BioProtoc.1712

Damage to plant organs through both biotic and abiotic injury is very common in nature. Arabidopsis thaliana 5-day-old (5-do) seedlings represent an excellent system in which to study plant responses to mechanical wounding, both at the site of the damage and in distal unharmed tissues. Seedlings of wild type, transgenic or mutant lines subjected to single or repetitive cotyledon wounding can be used to quantify morphological alterations (e.g., root length, Gasperini et al., 2015), analyze the dynamics of reporter genes in vivo (Larrieu et al., 2015; Gasperini et al., 2015), follow transcriptional changes by quantitative RT-PCR (Acosta et al., 2013; Gasperini et al., 2015) or examine additional aspects of the wound response with a plethora of downstream procedures. Here we illustrate how to rapidly and reliably wound cotyledons of young seedlings, and show the behavior of two promoters driving the expression of β-glucuronidase (GUS) in entire seedlings and in the primary root meristem, following single or repetitive cotyledon wounding respectively. We describe two procedures that can be easily adapted to specific experimental needs.
Preprints

Raschke, A.; Ibañez, C.; Ullrich, K. K.; Anwer, M. U.; Becker, S.; Glöckner, A.; Trenner, J.; Denk, K.; Saal, B.; Sun, X.; Ni, M.; Davis, S. J.; Delker, C.; Quint, M.; Natural Variants of ELF3 Affect Thermomorphogenesis by Transcriptionally Modulating PIF4-Dependent Auxin Response Genes bioRxiv (2015) DOI: 10.1101/015305

Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis. We identified GIRAFFE2.1, a major QTL explaining ~18% of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth. In combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod cues to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.
Preprints

Ibañez, C.; Poeschl, Y.; Peterson, T.; Bellstädt, J.; Denk, K.; Gogol-Döring, A.; Quint, M.; Delker, C.; Ambient temperature and genotype differentially affect developmental and phenotypic plasticity in Arabidopsis thaliana bioRxiv (2015) DOI: 10.1101/017285

Background Global increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best.Results Here, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown in four different temperatures ranging from 16 to 28 °C. We used Q10, GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions.Conclusion Genotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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