Jana Kaduková

Physiology of Matricaria chamomilla exposed to nickel excess.

Influence of nickel (Ni) excess on selected physiological aspects of Matricaria chamomilla metabolism after 10 days of presence was studied. Biomass, water content, assimilation pigments and lignin contents were not affected by any of the doses tested. High Ni doses elevated root-soluble proteins. The highest Ni concentration stimulated accumulation of soluble phenolics in both the rosettes and roots, and hydrogen peroxide in the roots. Malondialdehyde content was unaltered, but proline content increased more pronouncedly in the rosettes. Histidine was elevated in the roots, suggesting its involvement in Ni retention. Roots contained 3.4, 7.3 and 6.1 times more Ni than leaf rosettes with 3, 60 and 120 microM treatments, indicating that chamomile is a Ni excluder. Leaf rosettes accumulated 174.1 microg Ni g(-1) DW at 120 microM treatment. The results suggest chamomile tolerance to Ni excess and its considerable accumulation in above-ground biomass (ca. 30% of whole plant Ni content).

Physiological responses of Matricaria chamomilla to cadmium and copper excess.

Physiological responses of Matricaria chamomilla plants exposed to cadmium (Cd) and copper (Cu) excess (3, 60, and 120 μM for 7 days) with special emphasis on phenolic metabolism were studied. Cu at 120 μM reduced chamomile growth, especially in the roots where it was more abundant than Cd. Notwithstanding the low leaf Cu amount (37.5 μg g−1 DW) in comparison with Cd (237.8 μg g−1 DW) at 120 μM, it caused reduction of biomass accumulation, Fv/Fm ratio and soluble proteins. In combination with high accumulation of phenolics, strong reduction of proteins and high GPX activity in the roots, this supports severe redox Cu properties. In terms of leaf phenylalanine ammonia‐lyase (PAL) activity, it seems that Cd had a stimulatory effect during the course of the experiment, whereas Cu was found to stimulate it after 7‐day exposure. The opposite trend was visible in the roots, where Cd had a stimulatory effect at high doses but Cu mainly at the highest dose. This supports the assumption of different PAL time dynamics under Cd and Cu excess. A dose of 60 and 120 μM Cu led to 2‐ and 3‐times higher root lignin accumulation while the same Cd doses increased it by 33 and 68%, respectively. A Cu dose of 120 μM can be considered as limiting for chamomile growth under conditions of present research, while resistance to high Cd doses was confirmed. However, PAL and phenolics seemed to play an important role in detoxification of Cd‐ and Cu‐induced oxidative stress.

Determination of the Functional Groups in Algae Parachlorella Kessleri by Potentiometric Titrations

Abstract The acidic functional groups of the cell wall of native algae Parachlorella kessleri were evaluated by potentiometric titrations. The Gran´s method was applied to determination of the total, strong, weak and very weak acidities. The total organic acidity obtained for biomass was 3.93 mmol g-1, the largest content belonged to the strong acidic groups (2.13 mmol g-1) together with the weak acidic carboxylic groups (1.28 mmol g-1). Very weak acidities represented by the amine groups (0.52 mmol g-1) did not exceed 14% and they formed the lowest numerous part of all acidic functional groups.

Study of Ni And Cd Bioleaching from Spent Ni-Cd Batteries

Abstract In the present work the Ni and Cd extraction from the electrode material of spent Ni-Cd batteries by bioleaching using the bacteria Acidithiobacillus ferrooxidans was examined. The possibility of the use of the bacteria for both the Ni and Cd recovery was analyzed. The anode of Ni-Cd batteries contains Ni0, Ni(OH)2, Cd0 and Cd(OH)2. The cathode is covered by nickel hydroxides and nickel oxy-hydroxides. The pH values and content of Ni and Cd in the solution were monitored throughout the experiment (the initial pH was 1.5, the experiment took 28 days). The bioleaching efficiency of Ni and Cd from anode powder reached 5.5% and 98%, respectively. During the cathode powder bioleaching Ni and Cd efficiency reached 45% and 100%, respectively. Throughout the bioleaching process mainly the dissolution of hydroxides occurred meanwhile Ni0 leaching was not observed. The AAS analysis was used to analyze the amount of Ni and Cd in the solutions. The amount of Ni and Cd present in the solid samples before and after bioleaching was examined using X-ray analysis.

Assessment Of Biologically Synthesized Ag Nanoparticles Toxicity Against E. coli, Staphylococcus aureus, Parachlorella kessleri And Sinapis alba

Abstract In general, Ag+ ions and AgNPs are considered to be the most toxic for bacterial cells and less toxic for higher organisms. In the present work inhibitory effects of biologically prepared silver nanoparticles on the growth of bacteria E. coli CCM 3954 and Staphylococcus aureus CCM 3953, green microscopic alga Parachlorella kessleri LARG/1 and seed germination and root growth of plant Sinapis alba seeds were investigated. Surprisingly, silver nanoparticles showed much stronger inhibitory effects on plant seed germination and root growth than on the bacterial growth. At concentration of 75 mg/l AgNPs both seed germination and root growth of Sinapis alba was inhibited whereas inhibition of the growth of E. coli and S. aureus was observed at >195 mg/l. Growth inhibition of alga Parachlorella kessleri was recorded at 300 mg/l AgNPs concentration. The inhibitory effect of silver ions was much higher compared to silver nanoparticles. Even 20 mg/l concentration of Ag+ ions inhibited the root growth and concentration > 45 mg/l inhibited germination of Sinapis alba seeds. Inhibition zones in both studied bacteria were found at concentration > 140 mg/l.

Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

Abstract Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al) from printed circuit boards (PCBs). In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be 100, 92, 89 and 20% of Cu, Ni, Zn and Al, respectively. The mixed culture revealed higher bacterial stability. The main factor responsible for high metal recovery was the ability of the mixed culture to maintain the low pH during the whole process. The pure culture of A. thiooxidans had no significant effect on metal bioleaching from PCBs.

The Effect of Culture Age and Initial Silver Concentration on Biosynthesis of Ag Nanoparticles

Abstract Many organisms or their extracts have the ability to reduce Ag+ ions to Ag0 and stabilize them what results in nanoparticle formation in solution. The aim of the article was to study the influence of two selected parameters - initial silver concentration and culture age, on Ag nanoparticles production by green algae Parachlorella kessleri. The presence of Ag nanoparticles in the solution was confirmed by the UV-vis spectroscopy and TEM analyses. Typical curve with the peak at app. 420 nm was found for nanoparticles produced by algae. While culture age did not have any significant effect, the initial silver concentration had significant influence on nanoparticle production which influenced the rate of nanoparticle production, their amount, their size and stability, as well

The Evaluation of Heavy Metal Toxicity in Plants Using the Biochemical Tests

Abstract The evaluation of the toxicity and stress caused by heavy metals on plants is very important part of the phytoremediation research. Several physiological parameters can be used to assess the heavy metalinduced stress such as germination, plant growth and biomass production, photosynthetic pigments, antioxidant enzymes or antioxidants. Published results of measured physiological parameters in plants exposed to metals were characterized from of the negative effects of metals point of view and compared with the experimental study of the metal (Cu, Cd, Zn) toxicity in flax (Linum usitatissimum) and China aster (Callistephus chinensis) using the biochemical tests under the laboratory conditions. The germination and biomass production of C. chinensis significantly decreased with the increase of metal concentration which is considered a very typical response, however in L. usitatissimum slight stimulation of germination and biomass production at low metal content was observed. From the two studied plants C. chinensis expressed typical symptoms of the heavy metal toxicity including the decrease of total chlorophyll, chlorophylls a, b. On the contrary, heavy metal ions affected positively the physiological parameters of L. usitatissimum when low metal concentrations were added for example slight increase of the chlorophyll concentration in leaves was recorded. The decrease of the chlorophyll content was observed only at the high metal content. On the other hand, the typical response of plants on the heavy metal stress - the increase in peroxidase activity - was observed only for L. usitatissimum but not for C. chinensis that in all other tests showed significant toxicity symptoms. So if only one physiological parameter would be considered incorrect interpretation could be concluded. With the increase of phytoremediation practical applications the more systematic tests of heavy metal stress are necessary to help scientists working in that field correctly interpret their results and understand the plant behaviour.

Biosorption of Copper, Zinc and Nickel From Multi-Ion Solutions

Abstract The biosorption of Cu(II), Zn(II) and Ni(II) by microscopic green algae Chlorella kessleri was investigated using batch experiments. Biosorption studies with single and multi ion solutions were carried out to study the effect of several ions on the biosorption of selected metal. The influence of zinc and nickel on copper biosorption, copper and nickel on zinc biosorption and zinc and copper on nickel biosorption were investigated. The Langmuir and Freundlich model were used to describe the adsorption equilibrium of studied metals on Chlorella kessleri biomass. Based on the experimental results it was found that the presence of copper increased the biosorption capacity of zinc from 48.6 mg/g to 96.8 mg/g and nickel from 29.3 mg/g to 62.7 mg/g, respectively. However, the presence of nickel decreased the biosorption capacity of zinc from 48.6 mg/g to 31.7 mg/g.

Assessment of Microbially Influenced Corrosion Risk in Slovak Pipeline Transmission Network

Microbial activities are particularly serious in buried natural gas pipelines resulting in high corrosion costs. It is a mater of necessity to deal with this factor during the evaluation of corrosion risk. The objective of this investigation was to determine to what extent the main factors of environment are responsible for biocorrosion behavior in particular transmission pipeline sections running through Slovakia and subsequently evaluate the biocorrosion risk in the studied areas. According to the point method the probability and outcome value of three chosen factors, such as soil characteristics, water presence, and location were determined for each excavation. Two from the monitored excavations in the east of Slovakia and three situated in the south of Slovakia were found to be the most hazardous sites in terms of biocorrosion risk.