Search

Glucosinolates (GS) are secondary plant metabolites comprising different subgroups with opposing effects on human health. Hairy root cultures (HRC) are potent biotechnological tools allowing the biosynthesis of special substances under defined conditions. HRC of Eruca sativa, a brassicaceaous plant, were used to test different strategies to enhance GS levels and to alter the profile. Additional sulphur supply in the nutrient medium increased especially aliphatic GS by 2.7-fold, but also enhanced indole GS by 1.8-fold. Ethephon as well as jasmonic acid as chemical elicitors enhanced only indole GS levels, whereby especially 4-methoxyindol-3-ylmethyl or 1-methoxyindol-3-ylmethyl GS accumulated. Jasmonic acid was used in combination with pulsed electric field treatment as physical elicitor. Already within 24 h, GS levels doubled in treated HRC compared to the control. For estimation of production potency, the GS levels of HRC were compared to contents of aerial and root parts of E. sativa sprouts. HRC showed a distinct GS profile compared to the parent plant with a higher content of indole GS when compared to sprout roots, but overall lower total GS levels. Furthermore, HRC released GS into the culture medium, which could be enhanced by jasmonic acid and pulsed electric field treatment. This could comprise an efficient strategy for a continuous GS production and mining without solvent extraction. [ABSTRACT FROM AUTHOR]

Although short-wavelength light and especially UV radiation can induce resistance in plants against herbivorous insects, the optimal wavelengths, light intensities (photon flux rates), and illumination schedules for inducing resistance have not been previously determined. Light-emitting diode (LED) illumination enables researchers to subject insects and plants to narrow-banded light treatments. In this study, we assessed how the metabolite-based defense response in Brussels sprout plants ( Brassica oleracea var. gemmifera) against the cabbage aphid, Brevicoryne brassicae (Hemiptera: Aphididae), was affected by the following LED-generated wavelengths of light: 300 nm (UV-B), 365 nm (UV-A), 470 nm (blue light), and 660 nm (red light). Ambient greenhouse light supplemented with light from sodium vapor lamps served as the control treatment. The results showed a significant reduction in B. brassicae performance in the UV-A treatment compared to the blue light treatment; the reduction in the UV-A treatment was accompanied by a significant increase in glucosinolate concentrations. The UV-B treatment induced significant changes in plant flavonoid concentrations but did not affect B. brassicae performance. [ABSTRACT FROM AUTHOR]

Light of different wavelengths affects various physiological processes in plants. Short-wavelength radiation (like UV) can activate defense pathways in plants and enhance the biosynthesis of secondary metabolites (such as flavonoids and glucosinolates) responsible for resistance against certain herbivorous insects. The intensity of light-induced, metabolite-based resistance is plant- and insect species-specific and depends on herbivore feeding guild and specialization. In this study, broccoli ( Brassica oleracea var. italica) plants were grown for 4 weeks in a climate chamber under conventional fluorescent tubes and were additionally treated with UV-B (310 nm), UV-A (365 or 385 nm), or violet (420 nm) light generated with UV-B tubes or light-emitting diodes (LEDs). The objective was to determine the influence of narrow bandwidths of light (from UV-B to violet) on plant secondary metabolism and on the performance of the cabbage aphid Brevicoryne brassicae (a specialist) and the green peach aphid Myzus persicae (a generalist). Among flavonol glycosides, specific quercetin and kaempferol glycosides increased markedly under UV-B, while among glucosinolates only 4-methoxy-3-indolylmethyl showed a 2-fold increase in plants exposed to UV-B and UV-A. The concentration of 3-indolylmethyl glucosinolate in broccoli plants increased with UV-B treatment. Brevicoryne brassicae adult weights and fecundity were lower on UV-B treated plants compared to UV-A or violet light-treated plants. Adult weights and fecundity of M. persicae were increased under UV-B and UV-A treatments. When specific light wavelengths are used to induce metabolic changes in plants, the specificity of the induced effects on herbivores should be considered. [ABSTRACT FROM AUTHOR]

Aims: The effects of biofumigation with Brassica juncea 'Terra Plus' and Raphanus sativus 'Defender' in comparison to Basamid on apple plant growth and on soil microbial communities were studied at three sites affected by replant disease under field conditions. Methods: Apple rootstocks were planted on differently treated plots to evaluate the effect of the treatments on plant growth under field and greenhouse conditions. The glucosinolates in biofumigant plant organs and their breakdown products in soils were determined. Denaturing gradient gel electrophoresis fingerprints were performed with 16S rRNA gene and ITS fragments amplified from total community DNA extracted from different soils. Results: The highest glucosinolate concentrations were found in inflorescences of both biofumigant plant species with no differences between sites. The most abundant degradation product in soil biofumigated with B. juncea was 2-propenyl isothiocyanate, while in soil treated with R. sativus only 4-(methylthio)-3-butenyl isothiocyanate was detected. Effects of biofumigation were recorded to be stronger on fungi than on bacteria. Growth of apple rootstocks was positively affected by the treatments in a site-dependent manner. Conclusions: The effects of biofumigation evaluated by the apple plant growth were site-dependent and might result from suppression of soil-borne pests and pathogens, changes in soil microbial community compositions, and additional nutrients from the incorporated biomass. [ABSTRACT FROM AUTHOR]

Background: Nasturtium (Indian cress, Tropaeolum majus) is known for its pharmacological value in the treatment of bacterial infections of the upper air tract and urinary bladder. However, scientific data on the anti-inflammatory potency in human-derived cells is missing.Purpose: The aim of this study was to investigate the potential of nasturtium to inhibit the lipopolysaccharide (LPS) induced inflammatory response in primary human cells of the immune system.Study Design: The anti-inflammatory activities of nasturtium and its fractions were evaluated via regulation of arachidonic acid (AA) pathway and MAPK kinase cascade. Fraction H4 which was responsible for the anti-inflammatory effects was further characterized.Methods: Human peripheral blood mononuclear cells (PBMC) were either treated with plant extracts or fractions thereof, stimulated with LPS and/or N-formyl-methionyl-leucyl-phenylalanine (fMLP) and analysed for COX and LOX, release of prostaglandin PGE2, leukotriene LTB4, TNF-alpha and ERK signaling pathway activation. The plant extracts were separated into four fractions by HPLC; fraction H4 was subjected to UHPLC-ToF/MS analysis to identify potential bioactive compounds.Results: We found that aqueous extracts of nasturtium did exert strong concentration dependent suppression of LPS-triggered TNF-alpha release and COX pathway signaling, including PGE2 synthesis. Whereas COX-1 protein expression was not impacted, LPS-triggered COX-2 protein expression was concentration dependently blocked by the plant extract but not COX-2 enzyme activity. These findings suggest a mechanism of action for the plant extract which is different from non-steroidal anti-inflammatory drugs (NSAIDs). Moreover, the plant extract blocked leukotriene LTB4 release, the major end product of the 5-LOX pathway from PBMC. Down-regulation of ERK1/2 and c-Jun activation preceded COX-2 suppression upon plant extract treatment in the presence of LPS. Using HPLC separation of the aqueous extract followed by metabolomic analysis we could limit the number of relevant bioactive compounds in the extract to about 50.Conclusions: This study provides a rationale for the anti-inflammatory efficacy of nasturtium observed in man and gives first insight into the underlying molecular mechanisms. [ABSTRACT FROM AUTHOR]

The legume pod borer, Maruca vitrata, is a pantropical pest on leguminous crops. ( E,E)-10,12-Hexadecadienal, ( E,E)-10,12-hexadecadienol, and ( E)-10-hexadecenal were described previously as sex pheromone components for this nocturnal moth. A blend of these components in a ratio of 100:5:5 attracted males in field trapping experiments in Benin, but not in Taiwan, Thailand, or Vietnam. This finding suggests geographic variation in the pheromone blend between Asian and West African populations of M. vitrata. We, therefore, determined the pheromone compositions of single pheromone glands of females from the three Asian regions and from Benin by gas chromatography-mass spectrometry. Additionally, we compared the responses of males from Taiwan and Benin to calling females and to gland extracts of females from both regions in laboratory no-choice and two-choice assays. Chemical analysis revealed the presence of ( E,E)-10,12-hexadecadienal and ( E,E)-10,12-hexadecadienol, as well as the absence of ( E)-10-hexadecenal in all four populations. The relative amounts of the detected compounds did not vary significantly among the insect populations. The behavioral bioassays showed that Taiwanese and Beninese males were similarly attracted to females from both regions, as well as to their gland extracts. As a result, we did not find geographic variation in the sexual communication system of M. vitrata between West African and Asian insect populations. [ABSTRACT FROM AUTHOR]