Lenka Langhansova

ZnO nanoparticle effects on hormonal pools in Arabidopsis thaliana

At present, nanoparticles have been more and more used in a wide range of areas. However, very little is known about the mechanisms of their impact on plants, as both positive and negative effects have been reported. As plant interactions with the environment are mediated by plant hormones, complex phytohormone analysis has been performed in order to characterize the effect of ZnO nanoparticles (mean size 30nm, concentration range 0.16-100mgL-1) on Arabidopsis thaliana plants. Taking into account that plant hormones exhibit high tissue-specificity as well as an intensive cross-talk in the regulation of growth and development as well as defense, plant responses were followed by determination of the content of five main phytohormones (cytokinins, auxins, abscisic acid, salicylic acid and jasmonic acid) in apices, leaves and roots. Increasing nanoparticle concentration was associated with gradually suppressed biosynthesis of the growth promoting hormones cytokinins and auxins in shoot apical meristems (apices). In contrast, cis-zeatin, a cytokinin associated with stress responses, was elevated by 280% and 590% upon exposure to nanoparticle concentrations 20 and 100mgL-1, respectively, in roots. Higher ZnO nanoparticle doses resulted in up-regulation of the stress hormone abscisic acid, mainly in apices and leaves. In case of salicylic acid, stimulation was found in leaves and roots. The other stress hormone jasmonic acid (as well as its active metabolite jasmonate isoleucine) was suppressed at the presence of nanoparticles. The earliest response to nanoparticles, associated with down-regulation of growth as well as of cytokinins and auxins, was observed in apices. At higher dose, up-regulation of abscisic acid, was detected. This increase, together with elevation of the other stress hormone - salicylic acid, indicates that plants sense nanoparticles as severe stress. Gradual accumulation of cis-zeatin in roots may contribute to relatively higher stress resistance of this tissue.

Cultivation of root cultures of Panax ginseng in different bioreactors and in temporary immersion — Comparison of growth and saponin production

Different systems of large-scale cultivation of multiple adventitious roots of Panax ginseng C. A. Meyer were compared to cultivation in Erlenmeyer flasks. Adventitious roots were isolated from plantlets regenerated from somatic embryos and cultivated separately in liquid media. Multiplication of adventitious roots was performed in liquid Schenk and Hildebrandt (1972) medium containing 3% sucrose, and 24.6 µmol indole-3-butyric acid. The highest saponin content of 28.51 mg g−1 of dry weight was found in adventitious roots cultivated in the RITA® temporary immersion system (TIS). The best production of biomass was achieved in RITA® vessels and standard Erlenmeyer flasks placed on rotary shaker, followed by the Applikon 3-litre bioreactor and a simple airlift reactor. Saponin production in Erlenmeyer flasks was 10.07 mg g−1 of the dry weight while the production in the Applikon 3-litre bioreactor was only 3.60 mg g−1. Other bioreactor systems tested showed neither significant saponin production nor high biomass production.

Myrica rubra leaves as a potential source of a dual 5-LOX/COX inhibitor

ABSTRACT Myrica rubra Sieb. et Zucc. is a valuable fruit tree that is used in Chinese, Japanese and Taiwanese traditional medicine. We investigated the anti-inflammatory activity of M. rubra leaves extracted with four different solvents. Total phenolics were determined using the Folin–Ciocalteu method. Extracts were investigated for their inhibitory activity toward the pro-inflammatory enzymes cyclooxygenase-1 and -2 (COX-1, COX-2) and 5-lipoxygenase (5-LOX). The ethanol extract of M. rubra leaves demonstrated a strong inhibition of prostaglandin E2 (PGE2) biosynthesis catalyzed by both COX-1 (93.42%) and COX-2 (75.71%) and leukotriene B4 (LTB4) formation catalyzed by 5-LOX (82.72%). Further we identified selective COX-1 inhibition by the n-butanol and aqueous fractions of the ethanol extract (with an IC50 for COX-1 inhibition of 1.07 and 0.71 µg mL−1 , respectively) and dual 5-LOX/COX inhibition by the ethyl acetate fraction (with an IC50 of 3.29 for COX-1, 2.54 for COX-2 and 8.30 µg mL−1 for 5-LOX).

Increased Ginsenosides Production by Elicitation of In vitro Cultivated Panax Ginseng Adventitious Roots

Ginsenosides, which belong to group of triterpenoid saponins, are considered to be main constituents responsible for the biological effects of ginseng drug. Effect of organic and inorganic elicitors and other additives on the ginsenoside biosynthesis and biomass production by the in vitro cultivated adventitious root cultures of Korean ginseng was investigated in present study. Elicitation potential of natural mixtures (coconut water, pineapple extract, casein hydrolyzate, yeast extract, malt extract), organic elicitors (putrescine, spermidine, spermine, jasmonic acid), inorganic ions (calcium) and their complexes with organic acids (titanium ascorbate, titanium citrate) was tested. Changes in concentration of 9 main ginsenosides (Re, Rg1 , Rf, Rg2 , Rb1 , Rb2 , Rc, Rg3 and Rd) were monitored using HPLC-PDA and LC/MS/MS techniques. Jasmonic acid was the most effective elicitor of ginsenoside production (about 3.5 mg/g of DW in comparison with 1.4 mg/g of DW in control); however, its application (similar to spermine) was followed with significant reduction of the biomass growth. Among tested additives, casein hydrolyzate showed the highest increase of the ginsenoside content (2.2 mg/g DW) together with no effect on the growth of the culture. Both tested titanium complexes showed slight inhibition of the saponin accumulation in comparison with untreated control.

Transcriptomic response of Arabidopsis thaliana (L.) Heynh. roots to ibuprofen

ABSTRACT Surface waters in urban areas are contaminated by ibuprofen (IBP), a popular and extensively used anti-inflammatory drug. In this study, we investigated the transcriptomic response in Arabidopsis thaliana (L.) Heynh. roots with the aim of revealing genes that are potentially involved in IBP detoxification and elucidating the effect of IBP on plants. IBP upregulated 63 and downregulated 38 transcripts (p-value < 0.1, fold change ≥2) after 2-day exposure to a 5-µM (1.03 mg/L) concentration of IBP under hydroponic conditions. Although the IBP concentration used in the experiment was highly relative to the concentrations found in rivers and wastewater, the number of genes with transcriptional changes was relatively low. The upregulation of cytochrome P450s, glutathione S-transferases, and UDP-glycosyltransferases indicates the occurrence of IBP oxidation in the first phase, followed by conjugation with glutathione and sugar in the second detoxification phase. ABC transporters could be involved in the transport of IBP and its metabolites. The identification of genes potentially involved in IBP detoxification could be useful in an IBP phytoremediation approach.

Transcriptomic response of Arabidopsis thaliana roots to naproxen and praziquantel

Exposition to pharmaceutical compounds released to the environment is considered as a potential risk for various organisms. We exposed Arabidopsis thaliana plants to naproxen (NAP) and praziquantel (PZQ) in 5 µM concentration for 2 days and recorded transcriptomic response in their roots with the aim to estimate ecotoxicity and to identify gene candidates potentially involved in metabolism of both compounds. Nonsteroidal anti-inflammatory drug NAP up-regulated 105 and down-regulated 29 genes (p-value ≤ 0.1, fold change ≥ 2), while anthelmintic PZQ up-regulated 389 and down-regulated 353 genes with more rigorous p-value ≤ 0.001 (fold change ≥ 2). High number of up-regulated genes coding for heat shock proteins and other genes involved in response to biotic and abiotic stresses as well as down-regulation of genes involved in processes such as cell proliferation, transcription and water transport indicates serious negative effect of PZQ. NAP up-regulated mostly genes involved in various biological processes and signal transduction and down-regulated mainly genes involved in signal transduction and electron transport or energy pathways. Further, two cytochrome P450s (demethylation) and one methyltransferase (methylation of carboxyl group) were identified as candidates for phase I and several glutathione- and glycosyltransferases (conjugation) for phase II of NAP metabolism. Cytochrome P450s, glutathione and glycosyltransferases seem to play role also in metabolism of PZQ. Up-regulation of several ABC and MATE transporters by NAP and PZQ indicated their role in transport of both compounds.