Recruitment of alkaloid-specific homospermidine synthase (HSS) from ubiquitous deoxyhypusine synthase: Does Crotalaria possess a functional HSS that still has DHS activity?

2005 ◽  
Vol 66 (11) ◽  
pp. 1346-1357 ◽  
Author(s):  
Niknik Nurhayati ◽  
Dietrich Ober
Keyword(s):  
Deoxyhypusine Synthase ◽  
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 Hypusination, a Metabolic Posttranslational Modification of eIF5A in Plants during Development and Environmental Stress Responses

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1261
Author(s):  
Péter Pálfi ◽  
László Bakacsy ◽  
Henrietta Kovács ◽  
Ágnes Szepesi
Keyword(s):  
Amino Acid ◽  
Environmental Stress ◽  
Plant Development ◽  
Stress Responses ◽  
Posttranslational Modification ◽  
Proper Function ◽  
Signal Pathways ◽  
Deoxyhypusine Synthase ◽  
Deoxyhypusine Hydroxylase ◽  
Eukaryotic Translation

Hypusination is a unique posttranslational modification of eIF5A, a eukaryotic translation factor. Hypusine is a rare amino acid synthesized in this process and is mediated by two enzymes, deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Despite the essential participation of this conserved eIF5A protein in plant development and stress responses, our knowledge of its proper function is limited. In this review, we demonstrate the main findings regarding how eIF5A and hypusination could contribute to plant-specific responses in growth and stress-related processes. Our aim is to briefly discuss the plant-specific details of hypusination and decipher those signal pathways which can be effectively modified by this process. The diverse functions of eIF5A isoforms are also discussed in this review.

Polysome-seq as a Measure of Translational Profile from Deoxyhypusine Synthase Mutant in Saccharomyces cerevisiae

2020 ◽  
pp. 168-179
Author(s):  
Fernanda Manaia Demarqui ◽  
Ana Carolina Silva Paiva ◽  
Mariana Marchi Santoni ◽  
Tatiana Faria Watanabe ◽  
Sandro Roberto Valentini ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Deoxyhypusine Synthase

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.

scholarly journals Homospermidine biosynthesis in the cyanobacteriumAnabaenarequires a deoxyhypusine synthase homologue and is essential for normal diazotrophic growth

2018 ◽  
Vol 109 (6) ◽  
pp. 763-780 ◽  
Author(s):  
Mireia Burnat ◽  
Bin Li ◽  
Sok Ho Kim ◽  
Anthony J. Michael ◽  
Enrique Flores
Keyword(s):  
Deoxyhypusine Synthase ◽  
Diazotrophic Growth

scholarly journals Pyrrolizidine Alkaloids: Biosynthesis, Biological Activities and Occurrence in Crop Plants

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 498 ◽  
Author(s):  
Sebastian Schramm ◽  
Nikolai Köhler ◽  
Wilfried Rozhon
Keyword(s):  
Pyrrolizidine Alkaloids ◽  
Biological Activities ◽  
Structural Diversity ◽  
Plant Ecology ◽  
Crop Plants ◽  
Agricultural Products ◽  
Vast Number ◽  
Feeding Experiments ◽  
Novel Structures ◽  
Homospermidine Synthase

Pyrrolizidine alkaloids (PAs) are heterocyclic secondary metabolites with a typical pyrrolizidine motif predominantly produced by plants as defense chemicals against herbivores. They display a wide structural diversity and occur in a vast number of species with novel structures and occurrences continuously being discovered. These alkaloids exhibit strong hepatotoxic, genotoxic, cytotoxic, tumorigenic, and neurotoxic activities, and thereby pose a serious threat to the health of humans since they are known contaminants of foods including grain, milk, honey, and eggs, as well as plant derived pharmaceuticals and food supplements. Livestock and fodder can be affected due to PA-containing plants on pastures and fields. Despite their importance as toxic contaminants of agricultural products, there is limited knowledge about their biosynthesis. While the intermediates were well defined by feeding experiments, only one enzyme involved in PA biosynthesis has been characterized so far, the homospermidine synthase catalyzing the first committed step in PA biosynthesis. This review gives an overview about structural diversity of PAs, biosynthetic pathways of necine base, and necic acid formation and how PA accumulation is regulated. Furthermore, we discuss their role in plant ecology and their modes of toxicity towards humans and animals. Finally, several examples of PA-producing crop plants are discussed.

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