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Alfred Baumert

Bio: Alfred Baumert is an academic researcher from Leibniz Association. The author has contributed to research in topics: Acridone & Ruta graveolens. The author has an hindex of 19, co-authored 38 publications receiving 1189 citations. Previous affiliations of Alfred Baumert include Leibniz Institute for Neurobiology.

Papers
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Journal ArticleDOI
TL;DR: Evaluation of the antioxidative activity, conducted in vitro, by using electron spin resonance (ESR) and ultraviolet visible (UV-vis) spectrophotometric assays, showed that these isolated flavonoids possess strong antioxidative capabilities.

195 citations

Journal ArticleDOI
TL;DR: Regulation of gene expression at the transcript level seems to be responsible for changes of BnSGT1 and BNSCT activities during seed and seedling development of B. napus.
Abstract: Summary Members of the Brassicaceae family accumulate specific sinapate esters, i.e. sinapoylcholine (sinapine), which is considered as a major antinutritive compound in seeds of important crop plants like Brassica napus, and sinapoylmalate, which is implicated in UV-B tolerance in leaves. We have studied the molecular regulation of the sinapate ester metabolism in B. napus, and we describe expression of genes, some properties of the encoded proteins and profiles of the metabolites and enzyme activities. The cloned cDNAs encoding the key enzymes of sinapine biosynthesis, UDP-glucose (UDP-Glc):B. napus sinapate glucosyltransferase (BnSGT1) and sinapoylglucose:B. napus choline sinapoyltransferase (BnSCT), were functionally expressed. BnSGT1 belongs to a subgroup of plant GTs catalysing the formation of 1-O-hydroxycinnamoyl-β-d-glucoses. BnSCT is another member of serine carboxypeptidase-like (SCPL) family of acyltransferases. The B. napus genome contains at least two SGT and SCT genes, each derived from its progenitors B. oleracea and B. rapa. BnSGT1 and BnSCT activities are subjected to pronounced transcriptional regulation. BnSGT1 transcript level increases throughout early stages of seed development until the early cotyledonary stage, and stays constant in later stages. The highest level of BnSGT1 transcripts is reached in 2-day-old seedlings followed by a dramatic decrease. In contrast, expression of BnSCT is restricted to developing seeds. Regulation of gene expression at the transcript level seems to be responsible for changes of BnSGT1 and BnSCT activities during seed and seedling development of B. napus. Together with sinapine esterase (SCE) and sinapoylglucose:malate sinapoyltransferase (SMT), activities of BnSGT1 and BnSCT show a close correlation with the accumulation kinetics of the corresponding metabolites.

101 citations

Journal ArticleDOI
TL;DR: Members of the Brassicaceae accumulate complex patterns of sinapate esters, as shown in this communication with seeds of oilseed rape (Brassica napus), which gives rise to the assumption that enzymes of an SCPL acyltransferase family catalyze the appropriate transfer reactions to synthesize the accumulating esters.

96 citations

Journal ArticleDOI
TL;DR: Results demonstrate how the creation of a novel metabolic sink could divert the synthesis towards the production of piceid rather than sinapate ester, thereby increasing the value of oilseed products.
Abstract: Resveratrol is a phytoalexin produced in various plants like wine, peanut or pine in response to fungal infection or UV irradiation, but it is absent in members of the Brassicaceae. Moreover, resveratrol and its glucoside (piceid) are considered to have beneficial effects on human health, known to reduce heart disease, arteriosclerosis and cancer mortality. Therefore, the introduction of the gene encoding stilbene synthase for resveratrol production in rapeseed is a tempting approach to improve the quality of rapeseed products. The stilbene synthase gene isolated from grapevine (Vitis vinifera L.) was cloned under control of the seed-specific napin promotor and introduced into rapeseed (Brassica napus L.) by Agrobacterium-mediated co-transformation together with a ds-RNA-interference construct deduced from the sequence of the key enzyme for sinapate ester biosynthesis, UDP-glucose:sinapate glucosyltransferase (BnSGT1), assuming that the suppression of the sinapate ester biosynthesis may increase the resveratrol production in seeds through the increased availability of the precursor 4-coumarate. Resveratrol glucoside (piceid) was produced at levels up to 361 μg/g in the seeds of the primary transformants. This value exceeded by far piceid amounts reported from B. napus expressing VST1 in the wild type sinapine background. There was no significant difference in other important agronomic traits, like oil, protein, fatty acid and glucosinolate content in comparison to the control plants. In the third seed generation, up to 616 μg/g piceid was found in the seeds of a homozygous T3-plant with a single transgene copy integrated. The sinapate ester content in this homozygous T3-plant was reduced from 7.43 to 2.40 mg/g. These results demonstrate how the creation of a novel metabolic sink could divert the synthesis towards the production of piceid rather than sinapate ester, thereby increasing the value of oilseed products.

81 citations

Journal ArticleDOI
TL;DR: The effects of boron (B) deficiency on carbohydrate concentrations and the pattern of phenolic compounds were studied in leaves of tobacco plants and the accumulation of two caffeic acid amides was observed.

78 citations


Cited by
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Journal ArticleDOI
TL;DR: This review covers the isolation, structure determination, synthesis and biological activity of quinoline, quinazoline and acridone alkaloids from plant, microbial and animal sources.

1,687 citations

Journal ArticleDOI
TL;DR: This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids that represent their major form of carbon and energy storage in Arabidopsis.
Abstract: Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables.

1,169 citations

Journal ArticleDOI
TL;DR: Invertases, alone or in combination with plant hormones, can regulate many aspects of the growth and development of plants from gene expression to long-distance nutrient allocation and are involved in regulating carbohydrate partitioning, developmental processes, hormone responses and biotic and abiotic interactions.

842 citations

Journal ArticleDOI
TL;DR: A major focus of this review is the integration of information from genetic and biochemical studies with the unique insights gained from protein X-ray crystallography and homology modeling, which generated a number of new predictions regarding both the importance and mechanistic role of various amino acid substitutions observed among functionally diverse type III PKS enzymes.

833 citations

Journal ArticleDOI
TL;DR: The significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables are reviewed.
Abstract: Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

804 citations