The effects of different abiotic agents that may modulate the activity of an insect’s immune system are reviewed. These agents include insecticides, chitin synthesis inhibitors, juvenile hormone analogues, inert particles, antibiotics, heavy metals, radiation and miscellaneous substances. The significance of studying immunomodulation in insects treated with abiotic agents in relation to both insect control and insect-borne parasitic diseases and the link between immunomodulation in insects post-treatment with both abiotic and biotic agents are discussed., El-Sayed H. Shaurub., and Obsahuje seznam literatury
Intact cells of Synechococcus elongatus were treated with different concentrations (0.1 and 1.0 mM = Cd0.1, Cd1.0) of CdCl2 for 24 h. Cd0.1 treatment stimulated growth of the cell culture and chlorophyll (Chl) a concentration in the culture. Cd1.0 inhibited both the above mentioned parameters. The oxygen evolving activity of intact cells (H2O → BQ) as well as of isolated thylakoid membranes, TM (H2O → DCPIP; H2O → PBQ + FeCy) decreased after 24 h of Cd1.0 cultivation to 7 %. Photosystem 1 (PS1) activity was less sensitive to the effect of Cd2+ than PS2 activity. CdCl2 concentration in cultivation media after 24 h of cultivation proved that the cyanobacterium cells take up these ions to a large extent from the cultivation medium. After 24 h of the Cd1.0 treatment only 12 % of the amount of Cd2+ originally added to the cultivation medium was found. The ratio of external-antenna pigments, phycocyanin, and allophycocyanin to Chl increased approximately twofold with growing Cd2+ concentration in the cultivation medium. This ratio was found in both TM and dodecylmaltoside extracts. and E. Tůmová, D. Sofrová.
A combined sorbent was prepared by impregnation of lignite mined in the South Moravian Coalfield, Czech Republic, with chitosan. Sorption performance of the combined sorbent and the untreated lignite was tested for Co(II), Cu(II), and Cd(II) in equilibrium sorption experiments with respect to pH and metal concentration. The amount of metal retained by the sorbent was determined by instrumental neutron activation analysis in the short time irradiation mode with epithermal neutrons. For pH~5, sorption isotherms were determined and fitted using the Langmuir and Freundlich models. The results have been compared with those obtained previously for similar combined sorbent based on naturally oxidized coal mined in the Sokolov Basin, Czech Republic. It has been shown that the effect of chitosan on sorption efficiency of the chitosan-doped coal sorbents strongly depends on solution pH, and type of coal and metal., Martina Havelcová, Jiří Mizera, Vladimír Machovič, Lenka Borecká, Oldřich Přibyl and Ivana Krausová., and Obsahuje bibliografii
Following the Article 16 (7) of the Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for Community action in the field of water policy Commission shall submit proposals for environmental objectives applicable to the concentrations of the priority substances in surface water, sediments or biota. In the absence of agreement at Community level up to the deadline given by the directive Member States shall establish environmental objectives themselves. Within the framework of legislative preparation to this situation we have evaluated the relationships between particular parameters of surface water and total suspended solids contamination with heavy metals and with arsenic as one group of priority substances. Neither valid Decree No 82/1999 Coll. nor the amendment include such environmental objectives at present. and Podle čl. 16 (7) Směrnice 2000/60/ES Evropského parlamentu a Rady ustavující rámec pro činnost Společenství v oblasti vodní politiky má Komise předložit Evropskému parlamentu a Radě návrhy environmentálních standardů pro koncentrace prioritních látek v povrchových vodách, sedimentech a v biotě. V případě absence úmluvy na úrovni Společenství do termínu daného směrnicí musejí členské státy stanovit tyto environmentální standardy samy. V rámci legislativní přípravy na takovou eventualitu jsme proto hodnotili vztahy mezi jednotlivými parametry kontaminace vody a plavenin těžkými kovy a arsenem jako jednou skupinou prioritních látek. Platné Nař. vl. ČR č. 82/1999 Sb. ani připravovaná novela zatím environmentální standardy pro sedimenty (a tedy ani plaveniny) a biotu nezahrnují.
Thermoluminescence (TL) in green plants arises from charge recombination of charged molecules in the reaction centre (RC) of photosystem 2 (PS2) in chloroplasts. The TL technique is used for detection of alterations in the architecture of PS2 RCs. The donor side 'S-states' and the acceptor side quinone molecules (QA and QB) are involved the charge recombination processes of PS2. High temperature (70-75 °C) glow peaks are also used to detect non-photosynthetic peroxidation processes in thylakoid membranes. The TL peaks with their characteristic charge recombination can be utilised for the study of chloroplast development, ageing, chemical, biotic, and abiotic stress induced alterations in the PS2 RC and for the study of the primary photochemical events of photosynthesis. The technique has been used successfully in the characterisation of transgenic plants in the study of genetically engineered organisms. and A. N. Misra ... [et al.].
Cadmium is often detected in areas contaminated by heavy metals and the incidence of this element in dangerous concentrations has been increasing due to anthropogenic activities. The aim of this research was to determine Cd concentrations in tissues, quantify compounds, pigments and enzymes, and to evaluate the gas exchange. Our aim was also to identify components that can modify and contribute to tolerance of Cassia alata against Cd toxicity. We used five Cd concentrations (0, 22, 44, 88, and 132 μM) to validate our hypothesis. The Cd concentrations in tissues of C. alata plants increased significantly, compared with the control treatment, in the following graduated sequence: root > leaf > stem. Progressive enhancement in glutathione (GSH) was verified in plants treated with all Cd concentrations used, when compared with treatment without Cd. Antioxidant enzyme activities presented similar patterns with progressive enhancements, being a desirable characteristic for plants with a potential to hyperaccumulate Cd. Our results suggest that C. alata plants can be used for phytoremediation programs. Their defense mechanism is based on Cd accumulation in roots, coupled with increase in GSH and the efficient activity of antioxidant enzymes that contribute to minimize the oxidative stress and consequently improve the protection of the metabolic machinery., J. R. R. Silva, A. R. Fernandes, M. L. Silva Junior, C. R. C. Santos, A. K. S. Lobato., and Obsahuje bibliografii