A systematic study of the reduction of (ImH)[trans-RuCl(4)(dmso)(Im)] (NAMI-A; dmso is dimethyl sulfoxide, Im is imidazole), a promising antimetastasing agent, by L-ascorbic acid under physiological conditions is reported. Under blood plasma conditions (pH 7.4, 0.1-0.15 M NaCl , 37 degrees C) the rapid reduction of trans-[Ru(III)Cl(4)(dmso)(Im)](-) results in the formation of trans-[Ru(II)Cl(4)(dmso)(Im)](2-) within seconds, and is followed by successive dissociation of the chloride ligands, whereas neither dmso nor imidazole ligands are released during the reaction. Under our experimental conditions, the formation of the ascorbate dianion is the rate-determining step, and once it has formed it reacts rapidly with NAMI-A. Moreover, the NAMI-A complex is very unstable at physiological pH (7.4); therefore, the hydrolysis of NAMI-A cannot be excluded as a competing reaction. During hydrolysis, aquated derivatives via stepwise dissociation of chloride and dmso ligands are formed, and most of these species have a higher redox potential and are expected to be even more easily reduced by ascorbic acid. Thus, it is very likely that the reduced form of NAMI-A or the reduction products of its hydrolytic derivatives react with albumin. The reaction of reduced NAMI-A with human serum albumin leads to the formation of stable adducts, with a binding efficiency very similar to that of the parent complex, viz., 3.2+/-0.3 and 4.0+/-0.4 mol of Ru(II) and Ru(III) per mole of albumin, respectively, however with a significantly higher reactivity.

Chlorophyll derivatives are potentially dangerous xenobiotics of dietary origin. The interactions of water-soluble derivatives of chlorophyll a with the animal organism were investigated using chlorophyllide a and its Zn-substituted analogue as model xenobiotics. The chlorophyllides were administered to tumor-bearing mice and their uptake, distribution, and clearance were compared. The centrally bound metal determines important aspects of the in vivo behavior of metallochlorophyllides as xenobiotics. The uptake and clearance of chlorophyllide a were significantly faster than those of [Zn]-chlorophyllide a. Chlorophyllide a showed some tissue selectivity, while [Zn]-chlorophyllide a was uniformly distributed among tissues. Interestingly, the tissue levels of the latter compound were ten times higher than those of the Mg-derivative. These differences indicate that [Zn]-chlorophyllide a, in contrast to chlorophyllide a, is only weakly recognized by the system of active transport of xenobiotics and by enzymes involved in chlorophyll metabolism. The dependence of chlorophyllide pharmacokinetics on the central metal is of great relevance to chlorophyll-based phototherapy.

Tribenuron-methyl is the active substance of the herbicide used for weed control in crops. The aim of this study was to investigate differences in the metabolic response of seeds, seedlings and leaves of Centaurea cyanus L., depending on the degree of resistance to tribenuron-methyl. Changes in the values of selected biochemical and physiological parameters (germination index, chemical composition, photochemical efficiency of photosystem II and the emission spectra of blue-green fluorescence) presented herein make it possible to determine the differences between cornflower biotypes with various types of resistance to the tested herbicide. Moreover, differences in the chemical composition of dry seeds between biotypes susceptible and resistant to tribenuron-methyl were observed before using the herbicide. The degree of resistance to the herbicide-resistant or susceptible, but not the types of this resistance-mutational or metabolic, can be distinguished on the basis of the presented parameters. These findings allow for early diagnosis of the resistance of cornflower to tribenuron-methyl. Additionally, we suggest that the described parameters might be used as physiochemical markers for early estimation of weed resistance to various types of herbicide. The presented conclusions are especially important for agricultural practice.

We have investigated the influence of mechanical wounding of Arabidopsis rosette leaves on photochemical activity of photosystem II, gas exchange, sugar content and sucrose metabolism in wild-type plants and mutants impaired in hormonal balance. The aos (jasmonate deficiency), rcd1 (reduced sensitivity to ABA, ethylene, and methyl-jasmonate), and ein4 (ethylene insensitivity) mutants have been used. Generally, mechanical injury led to dynamic changes in metabolism, especially in sugar and carotenoid contents. Whereas all mutants showed lower photosynthesis and respiration in comparison to the wildtype plants, leaf wounding caused a decrease in respiration in aos and ein4, and an increase in respiration in wild type. The mechanical injury triggered an increase of the activities of sucrose hydrolysing enzymes, such as sucrose synthase (SuSy) and several types of invertases, which was most evident in case of rcd1 and aos plants. This was correlated with injury-related changes in soluble sugars in the mutants, but not in wild-type plants where sugar content was not significantly affected by wounding. The results confirm the key role of stress hormones, such as jasmonate and ethylene, in mediating stress responses after wounding. The outcome of the experiments also underlines important roles of SuSy and invertase in regeneration of injured tissues, most probably by providing precursors for cell wall biosynthesis and by modulating sugar-signalling in plant cells. Keywords Carbohydrates Á Chlorophyll a fluorescence Á FT-Raman spectroscopy Á Invertase Á Jasmonate-deficient mutant Á Sucrose synthase Abbreviations Aos JA deficient mutant CIN Neutral invertase cwINV Cell wall associated invertase ein4 Ethylene insensitive mutant Fv/Fm Photochemical efficiency of PSII JA Jasmonic acid NPQ Nonphotochemical quenching qP Quenching in steady-state QY Steady-state quantum yield rcd1-1 Radical-induced cell death 1 mutant with reduced sensitivity to ABA, ethylene, and methyl jasmonate ROS Reactive oxygen species SuSy Sucrose synthase VIN Vacuolar invertase W 2 2 h after wounding W 24 24 h after wounding Wt Wild type plants

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