Jan Triska

Metabolism of polychlorinated biphenyls by Solanum nigrum hairy root clone SNC-90 and analysis of transformation products

The study investigates aspects of PCB metabolism by a hairy root culture of Solanum nigrum L. (clone SNC-9O) in vitro. Standard conditions were established for efficient, up to 72% PCB conversion (22 individual PCB congeners examined in commercial mixture Delor 103, 5 g fresh biomass in 100 ml media shaken with 5 mg PCB for 14 days). The conversion products formed from three monochlorobiphenyls were monohydroxychlorobiphenyls and dihydroxychlorobiphenyls, while six dichlorobiphenyls yielded different monohydroxydichlorobiphenyls. Efficiency of the transformation of individual PCB congeners was evaluated together with phytotoxic effect on the clone SNC-9O. Major metabolites of monochlorobiphenyls analysed after extraction from biomass were hydroxylated at the position 4, and 4′, respectively.

Phytoremediation: biological cleaning of a polluted environment.

Phytoremediation is the direct use of living green plants to degrade, contain, or render harmless various environmental contaminants, including recalcitrant organic compounds or heavy metals. The methods involved include phytoextraction, direct phytodegradation, rhizofiltration, phytovolatilization or formation of artificial wetlands, and lagoon systems. More research background and the development of plants tailored for remediation purposes, using genetic engineering and deeper understanding of plant cooperation with microorganisms is needed. This approach is illustrated by our studies of heavy metal uptake improvement or studies of the PCB conversion, which include in-vitro screening of plant species, analysis of the products, evaluation of their toxicity and field plots, and also studies of enzymes and cloning of foreign genes into plants.

Elicitation of pharmacologically active substances in an intact medical plant.

The quality of medical plants used for the production of galenics or pharmacologically useful compounds is usually assessed by the content of biologically active compounds. Because most of these plants are grown in fields, this study focused on stimulation of active compounds by in vivo elicitation. Foliar application of elicitors on the immunostimulating medical plant purple coneflower ( Echinacea purpurea L. Moench.) grown on soil was used to increase the content of biologically active phenolics. Natural plant stress mediators and their derivatives (acetylsalicylic acid, salicylic acid, and methyl salicylate) as well as newly introduced biocompatible metal elicitor [titanium(IV) ascorbate] were chosen as active components of foliar sprays. A tremendous increase of phenolics (up to 10 times compared to control) and stimulation of the biomass yield were achieved. Tuning of organ specificity by modulation of the concentration of elicitor was also observed. This methodology represents a convenient alternative to cell suspension or hydroponic cultures being applicable in wide agricultural practice.

Project Tocoen: The fate of selected organic pollutants in the environment part xxiv. The content of PCBs and PCDDs/Fs in high‐mountain soils

The six high‐mountain soil samples (more than 1,100 m above sea level) from National Park Krkonose (North Bohemia, Czech‐Polish border) were analyzed for contents of PCBs, non‐ortho and mono‐ortho PCBs and PCDDs/Fs. The content of PCBs ranged between 31 and 137 ng.g‐1 dry soil. PCB 77 was predominant coplanar PCBs. The contents of PCDDs/Fs ranged between 17 and 29 pg.g‐1 1‐TEQ of PCDDs/Fs and were between 20.1 and 41.2 pg.g‐1 T‐TEQ of PCDDs/Fs and coplanar PCBs. The contents of PCDFs were significantly higher than those of PCDDs. The predominant congeners were OCDF and OCDD. The contribution of non‐ortho and mono‐ortho PCBs to the total 1‐TEQ ranged between 9.3 and 49.3%.

Occurence of eugenol, coniferyl alcohol and 3,4,5-trimethoxyphenol in common buckwheat (Fagopyrum esculentum Moench) and their biological activity

Common buckwheat (Fagopyrum esculentum Moench) is well known as a weed suppressing crop due to its strong competitive and allelopathic characteristics. The possible allelopathic compounds in buckwheat include compounds from different groups, such as flavonoids, fatty acids, phenolic acids, etc. Less attention has been paid to other phenolic compounds, specifically eugenol, o-eugenol, coniferyl alcohol and 3,4,5-trimethoxyphenol as possible allelochemicals. The effects of eugenol, o-eugenol, coniferyl alcohol, and 3,4,5-trimethoxyphenol on germination and plant growth were tested on seven plant species. The results of our study showed that eugenols, coniferyl alcohol, or 3,4,5-trimethoxyphenol are minority components of the buckwheat plant. Eugenol reached the highest concentration (1.16μg/g DW in buckwheat leaves) from these compounds and they probably do not have a significant function in the allelopathy of common buckwheat. However, due to the inhibitory effects on germination and plant growth, eugenol could be utilized in the plant protection of sustainable agriculture.

Optical detection of polychlorinated biphenyls

In this paper we describe the detection of polychlorinated biphenyls (PCBs) which is based on the measurement of changes of optical absorption at 400 nm of the medium in an aerobic bioreactor with immobilized cells Pseudomonas species 2. The rate of production, composition and the concentration of yellow intermediates are influenced by concentration and composition of PCB mixtures, concentration of cells and by the methods of immobilization. The method was applied in the detection of commercial mixture D103. It was found that the advantageous carriers were inorganic or organic-inorganic matrices, which sorbed PCBs and a cell outgrowth from their surface was low. In water contaminated with transformer oil and chlorinated hydrocarbons the detection limit is 10-2 gD103/kg. In transformer oil the upper limit for degradation of D103 by sodium dehalogenation (1.5 gD103 /kgoil) was determined also in the presence of the same concentration of trichloroethylene. The employment to of a liquid core waveguide spectrophotometer instead of a diode array spectrophotometer increased the sensitivity of the measurement of yellow intermediates by a factor of 100. An extrinsic fiber-optic sensor was used for in-situ measurement during biodegradation of PCBs in bioreactors.

Sensing technique of persistent organic pollutant uptake by forest trees using radio labeling

The atmospheric and/or the soil interactions of 14C- labelled hexachlorobenzene (HCB) with four-year-old Norway spruce cuttings originated from an autochthonous forest stand were analyzed in detail. The developed methodological approach can be applied for environmental investigations in different forest ecosystems polluted by persistent organic compounds.