The effect of cadmium-nickel interactions on superoxide production, cell viability and membrane potential (E_M) in roots of two maize cultivars

Effects of CdCl2, NiCl2 or both on superoxide production, viability and membrane potential (EM) of root cells in meristematic (MZ) and differentiation (DZ) zones of two maize cultivars (cv. Premia and cv. Blitz) were studied. Plants were supplied with 10 and 100 μM concentrations of heavy metals (HM). The responses in the studied parameters to HM were concentration- and time-dependent, and were found only in the cells of MZ. The treatment of roots with Cd-stimulated massive superoxide production, although to different extent depending on the cultivar, root zone, and metal concentration. The stimulating effect of Ni on oxidative burst in Cd-treated maize roots was related to an increased Cd-induced superoxide production. The cell death appeared between 24 and 48 h and between 12 and 24 h of the 10 μM and 100 μM metal treatments, respectively. This was in accordance with Cd-induced ROS (superoxide) production and the EM decline in the corresponding time periods. Cell viability, EM changes and partially superoxide production indicate that the impact of the metals on the studied parameters declined in the order Cd+Ni > Cd > Ni and that cv. Blitz tends to respond more sensitively than cv. Premia

Early cadmium-induced effects on reactive oxygen species production, cell viability and membrane electrical potential in grapevine roots

Cadmium (Cd) is one of the most worldwide concerned metal pollutants. It is able to induce reactive oxygen species production through indirect mechanisms causing oxidative stress. Vitis vinifera roots were treated with 100 μM Cd for 0-180 min or 20-100 μM Cd for 24 h. Fluorescence confocal microscopy showed elevated hydrogen peroxide and superoxide levels in the apical root segments. Two phases (after 30 min and 24 h) of the superoxide raised levels were observed. This was accompanied by the decrease in root cell viability. Cd in concentrations between 0.005-10 mM induced significant, but different changes in membrane electrical potential (EM) of the root epidermal cells. The low concentrations of Cd (0.005-0.01 mM) caused transient EM hyperpolarization followed by depolarization, whereas by higher concentrations (0.05-5.0 mM) EM was depolarized. In any case, the depolarization or hyperpolarization were only transient up to 5 mM Cd concentration indicating that the plasma membrane function was not irreversibly destroyed. Hyperpolarization of EM induced by fusicoccin (FC) was completely suppressed only in the presence of 10 mM Cd pointing to the inhibition of H+-ATPase. The results suggest that the Cd interactions, depending on cellular development, result in activation of a complex of various mechanisms such as peroxide and hydrogen peroxide production, which in turn may be a more probable reason for the root cell responses to Cd toxicity than the transient EM changes

The Effectiveness of Interactive Whiteboard Using Niesve System for Electrical Engineering Students

The article describes possibilities of increasing the effectiveness of teaching technical subjects using an interactive whiteboard. The basic research method is a pedagogical experiment by which we compare the effectiveness of teaching in the experimental and control group. In the experimental group was used experimental teaching with the support of an interactive whiteboard (on the platform of targeted use of the virtual way of visualising the course of processes and phenomena using an interactive whiteboard overlapping the natural possibilities of other ways of visualising these processes and phenomena). The control group was teaching traditionally taught without an interactive whiteboard. Research results (based on test results) have shown that the experimental teaching system we have used during this research is more effective than the traditional teaching system. By learning with an interactive whiteboard, we found that it was easier for students to acquire new knowledge. Students were able to use the acquired knowledge to solve practical tasks

Impact of nickel on grapevine (Vitis vinifera L.) root plasma membrane, ROS generation, and cell viability

The present study investigated the impact of nickel (Ni2+) on trans- membrane electrical potential (EM) and permeability properties of plasma membrane (PM) in epidermal cells of adventitious grapevine roots. The relationship between disturbances of membrane functionality and the production of superoxide anion, hydrogen peroxide and cell viability after the exposure of roots to Ni2+ was also studied. Treatments with 0.1–5 mmol L–1 NiCl2 induced a concentration-dependent transient PM depolarization, which was recovered to the initial resting potential within 50–70 min in the presence of Ni2+. Longer (up to 24 h) exposure of roots to 1 mmol L–1 of Ni2+ hyperpolarized the EM by approximately 17 mV. Application of the highest 5 mmol L–1 concentration of Ni2+ during longer treatments (up to 48 h) resulted in the increase of membrane permeability; however the EM, cell viability, and superoxide content remained unaffected. The increase in the formation of hydrogen peroxide was time- and concentration- dependent and maximum production was recorded after 180 min of Ni2+ treatment. We can conclude that oxidative stress resulting from an imbalance in the generation and/or removal of hydrogen peroxide in the root tissues of grapevine was the major cause of Ni2+ toxicity

Mathematical Modelling and Computer Simulation Assist in Designing Non-traditional Types of Precipitators and Separators

The article deals with the application of the method for mathematical modeling and simulation at solving some issues in the area of electrostatic technology. It focuses on the processes in electrostatic separation and precipitation. Computer simulation is highly required for equipment design and for their diagnostics in critical operating states using theoretical calculations and experimental data evaluation. The presented computer models may be applied both by project and design engineers using the most advanced computer-aided design of electrostatic technologies

Dissimilar responses of membrane potential (EM), permeability properties and respiration to cadmium and nickel in maize root cells

The short-term treatment with Cd2+ and Ni2+ triggered transient depolarization of transplasma membrane potential (EM) in the outer cortical root cells of two maize cultivars (cv. Premia and cv. Blitz), however, both metals changed the EM in a quantitatively different way. The magnitude and duration of EM depolarization were concentration dependent and were greater in the metal susceptible cv. Blitz. The highest EM depolarization was recorded with simultaneous application of Cd2+ + Ni2+ in both maize cultivars. The EM depolarization induced by Cd2+ or Cd2+ + Ni2+ but not Ni2+ alone was accompanied with a tremendous increase of membrane conductivity, but it was not accompanied with the effect of heavy metals (HM) on respiration. Simultaneous application of fusiccocin (FC) with Cd2+ or Cd2+ + Ni2+ during the EM depolarization, inability of FC to stop the depolarization by FC-enhanced proton extrusion and rapid restoration of EM, suggested a transient inhibition of the plasma membrane H+-ATPase by these toxic metals. Our data support the opinion that differences in the effects of the studied ions were not the result of their direct action on PM, but rather of their different influence on intracellular processes within root cells

Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd2+ content, and membrane potential (Em) in maize coleoptile segments were studied. In addition, the Em changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd2+ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K+-channel blocker) were also determined. In this study, the effects of Ca2+-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd2+ and Ca2+ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd2+ counteracted the toxic effect of Cd2+ on endogenous growth and significantly decreased Cd2+ content (not the case for Cd2+ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of Em, the extent of which was dependent on Cd concentration and time of treatment with Cd2+. Hyperpolarization of Em induced by FC was suppressed in the presence of Cd2+ at 1000 μM but not Cd2+ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of Em and decreased Cd2+ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd2+ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca2+ content in coleoptile segments. La and Ver combined with Cd2+ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd2+ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd2+ (except at 1000 μM Cd2+) on the growth of maize coleoptile segments involves both stimulation of PM H+-ATPase activity by FC as well as Cd2+-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization

Modeling of static step response of the controlled system a first order with the system rc2000

Príspevok sa zaoberá využitím systému rc2000 – μLAB na modelovanie statickej regulovanej sústavy 1. rádu. Teória automatického riadenia rozvíja metódy, ktoré sú vhodné na určenie riadenia reálnych objektov. Aby tieto metódy boli použiteľné na širokú triedu reálnych objektov, abstrahujeme od konkrétnych fyzikálnych vlastností týchto objektov a zaujímame sa iba o vzťahy medzi veličinami v týchto objektoch. Vytvárame abstraktné modely reálnych objektov, ktoré nazývame spojité systémy. Všetky veličiny v takýchto systémoch sú funkciou spojitého času t. Často možno vlastnosti objektov vyjadriť s dostatočnou presnosťou lineárnym modelom.The paper deals with using the system RC2000 – μLAB for modelling static controlled system 1st order. Theory of Automatic Control develops methods that are suitable for determining the management of real objects. That these methods are applicable to a wide class of real objects, abstract from the specific physical properties of these objects, and we are interested only in relations between the variables in these objects. We create abstract models of real objects, which we call continuous systems. All variables in such systems are a continuous function of time t. Properties of objects can often be expressed with sufficient precision linear model

ICT in the teaching of subject’s technique for primary school

Informačno-komunikačné technológie sú v súčasnej dobe neoddeliteľnou súčasťou každej sféry spoločenského života, vzdelávací proces nevynímajúc. Do škôl sa okrem počítačov zavádza i interaktívna tabuľa, ktorá poskytuje nielen priestor na motiváciu žiaka, ale ponúka i zážitkové učenie, ktorým si žiak lepšie osvojí poznatky individuálnou prácou. Interaktívna tabuľa predstavuje v našom prostredí pomerne novú technológiu, s jej použitím na školách súvisí viacero problémov. Jedným je nedostatočná pripravenosť učiteľov na využívanie tejto technológie, druhým je nedostatok výučbových materiálov použiteľných pre potreby interaktívnej tabule.Information and communication technologies are currently an integral part of every sphere of social life, not excluding the educational process. The schools, in addition to introducing comput-ers and interactive whiteboard, which not only provides space for student motivation, but also offers experiential learning whereby the student will master a better knowledge of individual work. Interactive whiteboard in our environment is a relatively new technology, with its use in schools is related to a number of problems. One is insufficient preparedness of teachers to use of this tech-nology; the second is the lack of teaching material for the needs applicable interactive whiteboard

Multimedia and e-learning – trend contemporary education

V úvode príspevku sú opísané niektoré možnosti multimédií a e-learningu vo vzdelávaní a tiež niekoľko konkrétnych aplikácii, ktoré realizujeme so svojimi študentmi jednak pre využitie na základných školách, stredných školách, ale aj pre štúdium študentov na fakulte. Snažíme sa, aby študenti aplikovali do vlastných multimediálnych materiálov všetky multimediálne prvky na sprostredkovanie informácií. Druhá časť príspevku obsahuje výsledky prieskumu, ktorým sme zisťovali názory študentov dennej aj externej formy štúdia na kvalitu a efektívnosť výučby predmetu multimediálna technika na katedre techniky a technológií, Fakulty prírodných vied Univerzity Mateja Bela v Banskej BystriciIn introduction contributions are describe opportunities multimedia and e-learning at educate and then some concretely applications, that are realize with our student nevertheless for exploitation on basic school, secondary school, but also for study the students' on university. We try, that students apply in own multimedia material all multimedia elements on mediation information. The second part contributions includes results research, which are poll the students' daily too external molds study on quality efficiency teaching subject multimedia technology on department techniques a technology, Faculty of natural sciences University of Matej Bel in Banská Bystric