scholarly journals Cell-Specific Expression of Homospermidine Synthase, the Entry Enzyme of the Pyrrolizidine Alkaloid Pathway in Senecio vernalis, in Comparison with Its Ancestor, Deoxyhypusine Synthase

2002 ◽  
Vol 130 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Stefanie Moll ◽  
Sven Anke ◽  
Uwe Kahmann ◽  
Robert Hänsch ◽  
Thomas Hartmann ◽  
...  
Keyword(s):  
Pyrrolizidine Alkaloid ◽  
Deoxyhypusine Synthase ◽  
Specific Expression ◽  
Homospermidine Synthase

scholarly journals Reduction of Pyrrolizidine Alkaloid Levels in Comfrey (Symphytum officinale) Hairy Roots by RNAi Silencing of Homospermidine Synthase

Planta Medica ◽  
2019 ◽  
Vol 85 (14/15) ◽  
pp. 1177-1186 ◽  
Author(s):  
Lars H. Kruse ◽  
Thomas Stegemann ◽  
Julia Jensen-Kroll ◽  
Annika Engelhardt ◽  
Anne-Maria Wesseling ◽  
...  
Keyword(s):  
Hairy Roots ◽  
Pyrrolizidine Alkaloid ◽  
Primary Metabolism ◽  
In Planta ◽  
Deoxyhypusine Synthase ◽  
Gene Encoding ◽  
Symphytum Officinale ◽  
Medicinal Plant Extracts ◽  
Cost Efficient ◽  
Homospermidine Synthase

AbstractComfrey is a medicinal plant, extracts of which are traditionally used for the treatment of painful inflammatory muscle and joint problems, because the plant contains allantoin and rosmarinic acid. However, its medicinal use is limited because of its toxic pyrrolizidine alkaloid (PA) content. PAs encompass more than 400 different compounds that have been identified from various plant lineages. To date, only the first pathway-specific enzyme, homospermidine synthase (HSS), has been characterized. HSS catalyzes the formation of homospermidine, which is exclusively incorporated into PAs. HSS has been recruited several times independently in various plant lineages during evolution by duplication of the gene encoding deoxyhypusine synthase (DHS), an enzyme of primary metabolism. Here, we describe the establishment of RNAi knockdown hairy root mutants of HSS in Symphytum officinale. A knockdown of HSS by 60 – 80% resulted in a significant reduction of homospermidine by ~ 86% and of the major PA components 7-acetylintermedine N-oxide and 3-acetylmyoscorpine N-oxide by approximately 60%. The correlation of reduced transcript levels of HSS with reduced levels of homospermidine and PAs provides in planta support for HSS being the central enzyme in PA biosynthesis. Furthermore, the generation of PA-depleted hairy roots might be a cost-efficient way for reducing toxic by-products that limit the medicinal applicability of S. officinale extracts.

scholarly journals The Orphan Crop Crassocephalum crepidioides Accumulates the Pyrrolizidine Alkaloid Jacobine in Response to Nitrogen Starvation

2021 ◽  
Vol 12 ◽  
Author(s):  
Sebastian Schramm ◽  
Wilfried Rozhon ◽  
Adebimpe N. Adedeji-Badmus ◽  
Yuanyuan Liang ◽  
Shahran Nayem ◽  
...  
Keyword(s):  
Pyrrolizidine Alkaloid ◽  
Sub Saharan Africa ◽  
Close Relative ◽  
Environmental Cues ◽  
N Deficiency ◽  
Sub Saharan ◽  
Rate Limiting ◽  
Homospermidine Synthase ◽  
Orphan Crop

Crassocephalum crepidioides is an African orphan crop that is used as a leafy vegetable and medicinal plant. Although it is of high regional importance in Sub-Saharan Africa, the plant is still mainly collected from the wild and therefore efforts are made to promote its domestication. However, in addition to beneficial properties, there was first evidence that C. crepidioides can accumulate the highly toxic pyrrolizidine alkaloid (PA) jacobine and here it was investigated, how jacobine production is controlled. Using ecotypes from Africa and Asia that were characterized in terms of their PA profiles, it is shown that the tetraploid C. crepidioides forms jacobine, an ability that its diploid close relative Crassocephalum rubens appears to lack. Evidence is provided that nitrogen (N) deficiency strongly increases jacobine in the leaves of C. crepidioides, that this capacity depends more strongly on the shoot than the root system, and that homospermidine synthase (HSS) activity is not rate-limiting for this reaction. A characterization of HSS gene representation and transcription showed that C. crepidioides and C. rubens possess two functional versions, one of which is conserved, that the HSS transcript is mainly present in roots and that its abundance is not controlled by N deficiency. In summary, this work improves our understanding of how environmental cues impact PA biosynthesis in plants and provides a basis for the development of PA-free C. crepidioides cultivars, which will aid its domestication and safe use.

Microarray analysis reveals pivotal divergent mRNA expression profiles early in the development of either compensated ventricular hypertrophy or heart failure

2005 ◽  
Vol 21 (3) ◽  
pp. 314-323 ◽  
Author(s):  
Henk P. J. Buermans ◽  
Everaldo M. Redout ◽  
Anja E. Schiel ◽  
René J. P. Musters ◽  
Marian Zuidwijk ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Ventricular Remodeling ◽  
Contractile Function ◽  
Pyrrolizidine Alkaloid ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Pressure Overload ◽  
High Dose ◽  
Specific Expression

Myocardial right ventricular (RV) hypertrophy due to pulmonary hypertension is aimed at normalizing ventricular wall stress. Depending on the degree of pressure overload, RV hypertrophy may progress to a state of impaired contractile function and heart failure, but this cannot be discerned during the early stages of ventricular remodeling. We tested whether critical differences in gene expression profiles exist between ventricles before the ultimate development of either a compensated or decompensated hypertrophic phenotype. Both phenotypes were selectively induced in Wistar rats by a single subcutaneous injection of either a low or a high dose of the pyrrolizidine alkaloid monocrotaline (MCT). Spotted oligonucleotide microarrays were used to investigate pressure-dependent cardiac gene expression profiles at 2 wk after the MCT injections, between control rats and rats that would ultimately develop either compensated or decompensated hypertrophy. Clustering of significantly regulated genes revealed specific expression profiles for each group, although the degree of hypertrophy was still similar in both. The ventricles destined to progress to failure showed activation of pro-apoptotic pathways, particularly related to mitochondria, whereas the group developing compensated hypertrophy showed blocked pro-death effector signaling via p38-MAPK, through upregulation of MAPK phosphatase-1. In summary, we show that, already at an early time point, pivotal differences in gene expression exist between ventricles that will ultimately develop either a compensated or a decompensated phenotype, depending on the degree of pressure overload. These data reveal genes that may provide markers for the early prediction of clinical outcome as well as potential targets for early intervention.

scholarly journals Low pyrrolizidine alkaloid levels in perennial ryegrass is associated with the absence of a homospermidine synthase gene

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Geoffrey P. Gill ◽  
Catherine J. Bryant ◽  
Mikhail Fokin ◽  
Jan Huege ◽  
Karl Fraser ◽  
...  
Keyword(s):  
Perennial Ryegrass ◽  
Pyrrolizidine Alkaloid ◽  
Homospermidine Synthase

scholarly journals Pyrrolizidine Alkaloid Biosynthesis in Phalaenopsis Orchids: Developmental Expression of Alkaloid-Specific Homospermidine Synthase in Root Tips and Young Flower Buds

2008 ◽  
Vol 148 (2) ◽  
pp. 751-760 ◽  
Author(s):  
Sven Anke ◽  
Daniela Gondé ◽  
Elisabeth Kaltenegger ◽  
Robert Hänsch ◽  
Claudine Theuring ◽  
...  
Keyword(s):  
Pyrrolizidine Alkaloid ◽  
Developmental Expression ◽  
Alkaloid Biosynthesis ◽  
Root Tips ◽  
Flower Buds ◽  
Homospermidine Synthase
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