The activity of antioxidant enzymes, copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as that of the mitochondrial FAD-dependent a-glycerophosphate dehydrogenase (a-GPD) in the rat interscapular brown adipose tissue (IBAT) were studied after the treatment with methimazole (MMI) for three weeks or with iopanoic acid (IOP) for five days. Besides, the mitochondrial concentration of uncoupling protein-1 (UCP-1) and the activity of catecholamine degrading enzyme monoamine oxidase (MAO) in the IBAT as well as the activity of the catecholamine synthesizing enzyme, dopamine b-hydroxylase (DBH) in rat serum were examined. Judging by the significantly enhanced level of serum DBH, which is an index of sympathetic activity, and that of IBAT MAO, the increase in MnSOD and CAT activities in the IBAT of hypothyroid (MMI-treated) rats seems to be due to elevated activity of sympathetic nervous system (SNS). However, CuZnSOD activity is not affected by SNS. On the contrary, IOP, which is a potent inhibitor of T4 deiodination into T3 producing "local" hypothyroidism, did not change either SNS activity or activities of IBAT antioxidant enzyme. However, both treatments significantly decreased IBAT UCP-1 content and a-GPD activity suggesting that the optimal T3 concentration in the IBAT is necessary for maintaining basal levels of these key mitochondrial parameters., N. Petrović, G. Cvijić V. Davidović., and Obsahuje bibliografii
The altitudinal effects on photosynthesis were measured on progenies of three populations of Rosa platyacantha Schrenk from altitudes of 1,170 (L); 1,580 (M); and 1,920 (H) m a. s. l. During the day, net photosynthetic rate (PN) decreased in all populations due to the high air temperature in the summer. The H population showed a significantly lower PN at noon compared to other populations. The midday depression of PN occurred in L and M populations due to stomatal limitations, while PN inhibition was associated with PSII activity decline in the H population. In order to avoid photodamage, the plants of H population triggered active antioxidant defenses with a higher enzyme activity and redox ratio of ascorbate at midday compared to the L and M populations. However, more oxidative injury still occurred in the H plants at noon due to higher lipid peroxidation. Our results indicated that the provenance significantly affected photosynthesis in R. platyacantha from northwestern China., S. H. Yang, J. J. Wei, H. Ge., and Obsahuje bibliografii
Photoinhibition is a significant constraint for improvement of radiation-use efficiency and yield potential in cereal crops. In this work, attached fully expanded leaves of seedlings were used to assay the factors determining photoinhibition and for evaluation of tolerance to photoinhibition in wheat (Triticum aestivum L.). Our results showed that even 1 h under PPFD of 600 µmol(photon) m-2 s-1 could significantly reduce maximal quantum yield of PSII photochemistry (Fv/Fm) and performance index (PI) compared to low light [300 µmol(photon) m-2 s-1]. The decrease of Fv/Fm and PI was more noticeable with the increase of light intensity; irradiance higher than 800 µmol(photon) m-2 s-1 resulted in photoinhibition. Compared to 25°C, lower (20°C) or higher temperature (≥ 35°C) aggravated photoinhibition, while slightly high temperature (28°) alleviated photoinhibition. At 25°C, irradiance of 1,000 µmol(photon) m-2 s-1 for 1 h was enough to cause photoinhibition and a significant decrease of Fv/Fm, PI, trapped energy flux, electron transport flux, and density of reaction center as well as increase of dissipated energy flux per cross section were observed. In addition, seedlings at 21-32 days after planting showed a relatively stable phenotype, while the younger or older seedlings indicated an increased susceptibility to photoinhibition, especially in senescing leaves. Finally, six wheat varieties with relative tolerance to photoinhibition were identified from 22 Chinese winter wheat varieties by exposing attached leaves of the 25-d old seedlings for 1 h to 1,000 µmol(photon) m-2 s-1 at 25°C. Therefore, our work established a possible method for development of new wheat varieties with enhanced tolerance to photoinhibition., H. Li, Q. Zheng, J. Zhang, B. Li, Z. Li., and Obsahuje bibliografii
The goal of this study is to determine the validity of morpholineaments network that was inferred based on morphostructural analysis of digital elevation model (DEM), by crosschecking with documented faults. The test field has been spread over the exploitation areas in the Zlaté Hory ore district. Various morphometric analyses such as slope, aspect, first directional derivative, gradient operator, combination of altitude and shaded relief, were chosen as particular tools of the morphostructural analysis. The results of each analysis were compared with the results of structural-tectonic mapping. The inferred morpholineaments network was compared with mining maps of the scale 1:500, which provide detailed information about tectonic deformation of rock massif in the area of interest and were used to image fault traces on the surface. The validity of inferred morpholineaments network was determined by authorized software SROV_TEKT, developed by the authors. The morpholineaments network resulting from the morphostructural analysis and tested by this software overlaps at 83 % of the documented main faults in the mines., Jan Jelínek, František Staněk, Jan Thomas, Tomáš Daněk and Jiří Mališ., and Obsahuje bibliografii