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274522. Effects of cadmium stress upon activities of antioxidative enzymes, photosynthetic rate, and production of phytochelatins in leaves and chloroplasts of wheat cultivars differing in yield potential
- Creator:
- Ahmad, I., Naeem, M., Khan, N. A., and Samiullah
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- ascorbate peroxidase, ATP-sulfurylase, catalase, glutathione, glutathione reductase, stomatal conductase, superoxide dismutase, Triticum, and water use efficiency
- Language:
- Multiple languages
- Description:
- We tested the mode of action of Cd on photosynthesis and activities of ATP-sulfurylase (ATP-S), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), and on contents of phytochelatins (PCs) and glutathione (GSH) in two cultivars of wheat (Triticum aestivum L.) PBW-343 and WH-542 differing in yield potential. Cd treatment increased Cd content and photosynthetic activity in PBW-343 more than in WH-542. The activities of APX, GR, ATP-S, and synthesis of PCs and GSH were also increased by Cd, but the CAT and SOD activities were inhibited in both the cultivars. The efficient functioning of antioxidative enzymes, production of PCs and GSH, helped in counteracting the effects of Cd namely in PBW-343, protected photosynthetic ability, and increased the tolerance to Cd. and I. Ahmad ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274523. Effects of caffeine at different temperatures on contractile properties of slow-twitch and fast-twitch rat muscles
- Creator:
- Wondmikun , Y., Soukup, T., and Asmussen , G.
- Type:
- article, model:article, and TEXT
- Subject:
- Rat, Slow and fast muscles, Contractile properties, Caffeine, Temperature dependence, and Calcium transients
- Language:
- English
- Description:
- The slow-twitch soleus muscle (SOL) exhibits decreased twitch tension (cold depression) in response to a decreased temperature, whereas the fast-twitch extensor digitorum longus (EDL) muscle shows enhanced twitch tension (cold potentiation). On the other hand, the slow-twitch SOL muscle is more sensitive to twitch potentiation and contractures evoked by caffeine than the fast-twitch EDL muscle. In order to reveal the effects of these counteracting conditions (temperature and caffeine), we have studied the combined effects of temperature changes on the potentiation effects of caffeine in modulating muscle contractions and contractures in both muscles. Isolated muscles, bathed in a Tyrode solution containing 0.1-60 mM caffeine, were stimulated directly and isometric single twitches, fused tetanic contractions and contractures were recorded at 35 °C and 20 °C. Our results showed that twitches and tetani of both SOL and EDL were potentiated and prolonged in the presence of 0.3-10 mM caffeine. Despite the cold depression, the extent of potentiation of the twitch tension by caffeine in the SOL muscle at 20 °C was by 10-15 % higher than that at 35 °C, while no significant difference was noted in the EDL muscle between both temperatures. Since the increase of twitch tension was significantly higher than potentiation of tetani in both muscles, the twitch-tetanus ratio was enhanced. Higher concentrations of caffeine induced contractures in both muscles; the contracture threshold was, however, lower in the SOL than in the EDL muscle at both temperatures. Furthermore, the maximal tension was achieved at lower caffeine concentrations in the SOL muscle at both 35 °C and 20 °C compared to the EDL muscle. These effects of caffeine were rapidly and completely reversed in both muscles when the test solution was replaced by the Tyrode solution. The results have indicated that the potentiation effect of caffeine is both time- and temperature-dependent process that is more pronounced in the slow-twitch SOL than in the fast-twitch EDL muscles.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274524. Effects of calcium leaching on interfacial properties of PVA fibers in cementitious matrix
- Creator:
- Kabele, Petr, Němeček, Jiří, Novák, Luděk, and Kopecký, Luboš
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- calcium leaching, PVA fiber, and cementitious matrix
- Language:
- English
- Description:
- Since fiber reinforced composites are often used in an aggressive environment (bridge decks, drainage pipes etc.), it is necessary to estimate their durability and ability to maintain superior mechanical properties in such conditions. One of microscale mechanisms that has a dominant influence on achieving desirable mesomechanical behavior, such as multiple cracking, is fiber-matrix interfacial bond. In the present study, the effect of calcium leaching on the bond properties and fiber-matrix interfacial one are experimentally investigated. To this end, a series of tests is performed, in which a single fiber is pulled out from cementitious matrix under displacement control. Both chemical and frictional bonds are calculated from the measured load-displacement curves, and the effect of environmental exposure on these parameters is clarified. In order to gain a deeper insight into the microscale mechanical phenomena associated with calcium leaching, the fiber-matrix interfaces of both control and chemically attacked specimens are examined by nanoindentation and ESEM. These experiments show that leaching severely degrades the stiffness of the farther transitional zone. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274525. Effects of carbonated water injection on the pore system of a carbonate rock (coquina)
- Creator:
- Silveira, Thaís M., Hoerlle, Fernanda, Rocha, Adriano S., Lima, Maira C. O., Ramirez, Mateus G., Pontedeiro, Elizabeth M., van Genuchten, Martinus Th., Cruz, Daniel O. A., and Couto, Paulo
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- carbonate rocks, coreflooding, Pore Size Distribution, Pore Network Analysis, and PoreStudio
- Language:
- Slovak
- Description:
- CO2 injection is a well-known Enhanced Oil Recovery (EOR) technique that has been used for years to improve oil extraction from carbonate rock and other oil reservoirs. Optimal functioning of CO2 injection requires a thorough understanding of how this method affects the petrophysical properties of the rocks. We evaluated pore-scale changes in these properties, notably porosity and absolute permeability, following injection of CO2-saturated water in two coquina outcrop samples from the Morro do Chaves Formation in Brazil. The coquinas are close analogues of Presalt oil reservoirs off the coast of southern Brazil. The effects of carbonated water injection were evaluated using a series of experimental and numerical steps before and after coreflooding: cleaning, basic petrophysics, microtomography (microCT) imaging, nuclear magnetic resonance (NMR) analyses, and pore network modeling (PNM). Our study was motivated by an earlier experiment which did not show the development of a wormhole in the center of the sample, with a concomitant increase in permeability of the coquina as often noted in the literature. We instead observed a substantial decrease in the absolute permeability (between 71 and 77%), but with little effect on the porosity and no wormhole formation. While all tests were carried out on both samples, here we present a comprehensive analysis for one of the samples to illustrate changes at the pore network level. Different techniques were used for the pore-scale analyses, including pore network modeling using PoreStudio, and software developed by the authors to enable a statistical analysis of the pore network. Results provided much insight in how injected carbonated water affects the pore network of carbonate rocks.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274526. Effects of Cd on photosynthesis and growth of safflower (Carthamus tinctorius L.) genotypes
- Creator:
- Moradi, L. and Ehsanzadeh, P.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, cadmium, chlorophyll, gas exchange, lipid peroxidation, proline, 2, and 581
- Language:
- Multiple languages
- Description:
- Heavy metals such as cadmium (Cd) may affect different physiological functions in plants. We carried out a hydroponic experiment under greenhouse conditions in order to evaluate the effect of Cd on photosynthetic and physiological parameters of safflower. The responses of six safflower genotypes (Nebraska-10, 2811, Kouseh, S149, C111, and K12) to four concentrations of CdCl2 (0, 1.5, 3, and 4.5 mg L-1) were examined. Mean shoot and root dry masses of safflower plants were reduced by nearly 57% after the treatment by 4.5 mg(CdCl2) L-1. Contrary to the mean proline content, which increased by 121%, the mean total leaf area per plant, net photosynthetic rate, stomatal conductance to the CO2, leaf chlorophyll a, b, and (a+b), carotenoid content, and quantum efficiency of PSII decreased by 84.4, 50.5, 50.0, 31.6, 32.2, 31.8, 32.9, and 11.2%, respectively, at the presence of 4.5 mg(CdCl2) L-1. The mean Cd concentration in shoots and roots of safflower genotypes exhibited 52- and 157-fold increase, respectively, due to the addition of 4.5 mg(CdCl2) L-1 to the growing media. The mean malondialdehyde content was enhanced by 110% with the increasing CdCl2 concentration, indicating the occurrence of a considerable lipid peroxidation in the plant tissues. Even though the membrane stability index was adversely affected by the application of 1.5 mg(CdCl2) L-1, the decrease ranged from 45 to 62% when plants were treated with 4.5 mg(CdCl2) L-1. Genotype Nebraska-10 seemed to be different from the remaining genotypes in response to the 4.5 mg(CdCl2) L-1; its net photosynthetic rate tended to be the greatest and the Cd concentration in shoots and roots was the lowest among genotypes studied. This study proved Cd-induced decline in growth, photosynthesis, and physiological functions of safflower., L. Moradi, P. Ehsanzadeh., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274527. Effects of certain inducers of leukocytes migration into the bovine mammary gland on neutrophil apoptosis manifestation in a subsequent in vitro cultivation
- Creator:
- Ryšánek, D., Sládek, Z., Vašíčková, D., and Faldyna, M.
- Type:
- article, model:article, and TEXT
- Subject:
- Heifers, Virgin mammary gland, Leukocyte influx, Inducers, Neutrophils, and Apoptosis
- Language:
- English
- Description:
- The aim of the study was to elucidate the effects of induced leukocyte migration into the bovine mammary gland on the manifestations of early and late apoptotic features of neutrophils cultivated in vitro. The Latin square design was used in two experiments, each involving four experimental repetitions in 4 clinically healthy virgin heifers. The neutrophil early apoptotic features were detected by flow cytometric detection (FCM) of phosphatidyl-serine translocation. Late neutrophil apoptotic features were detected by ELISA quantitation of histone-complexed DNA fragments. Leukocyte influx induction was accomplished by using four inducers: i) sterile buffered saline solution (PBS); ii) 5 % glucose solution (GLU); iii) synthetic muramyl dipeptide analogue (MDP); and iv) lipopolysaccharide (LPS), administered into the mammary gland lumen. Leukocytes from mammary glands were obtained by mammary gland lumen lavages after influx induction. The total cell counts in lavages increased after treatment by all inducers in comparison to the counts before influx induction (P<0.001). Cell counts were higher and differed significantly by MDP and LPS (P<0.01) in contrast to PBS. The highest proportion of neutrophils was induced by LPS (P<0.01). After three-hour incubation, light microscopy examination revealed the highest manifestation of neutrophil apoptosis after induction by GLU (P<0.05). The lowest apoptosis manifestation, though statistically non-significant, was detected after induction by MDP and LPS. Determination of early manifestation of neutrophil apoptosis revealed the lowest manifestation of neutrophil apoptosis after induction by LPS (P<0.01). The results of late manifestation of neutrophil apoptosis revealed the highest proportion of apoptotic neutrophils after induction by GLU (P<0.05). The manifestation of secondary necrosis of apoptotic neutrophils or neutrophil lysis after 3 h of incubation was low and not significant. In conclusion, certain inducers of neutrophil migration into the lumen of bovine mammary glands (GLU and LPS in the present experiments) significantly influence the manifestation of neutrophil apoptosis during their subsequent in vitro incubation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274528. Effects of Changes in Tax/Benefit Policies in Austria 2003-2005
- Creator:
- Fuchs, Michael and Lietz, Christine
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- policy reform, micro-simulation, income inequality, redistribution, and Austria
- Language:
- Czech
- Description:
- The aim of this paper is to evaluate whether policy reforms in Austria between 2003 and 2005 were successful in meeting redistributive objectives and in reducing poverty. The authors use the tax/benefit micro-simulation model EUROMOD for this analysis. In the period under review the 2004-2005 tax reform was introduced and contributions to health insurance were raised. On the benefit side no major changes took place, the main family benefits were not even indexed to inflation. The authors find that the measures had no significant impact on poverty and income distribution. However, in total they increased the disposable income of almost all groups of the population.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274529. Effects of chilling temperature on the activity of enzymes of sucrose synthesis and the accumulation of saccharides in leaves of three sugarcane cultivars differing in cold sensitivity
- Creator:
- Du, Yu-Chun and Nose, Akihiro
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- C4 plants, cold temperature, cytosolic fructose-1,6-bisphosphatase, photosynthesis, saccharides, sucrose phosphate synthase, sucrose metabolism, and Saccharum
- Language:
- Multiple languages
- Description:
- The effects of short-term exposure to chilling temperature (10 °C) on sucrose synthesis in leaves of the cold-tolerant sugarcane cultivars Saccharum sinense R. cv. Yomitanzan and Saccharum sp. cv. NiF4, and the cold-sensitive cultivar S. officinarum L. cv. Badila were studied. Plants were grown at day/night temperatures of 30/25 °C, and then shifted to a constant day/night temperature of 10 °C. After 52-h exposure to the chilling temperature, sucrose content in the leaves of NiF4 and Yomitanzan showed a 2.5- to 3.5-fold increase relative to that of the control plants that had been left on day/night temperatures of 30/25 °C. No such increase was observed in Badila leaves. Similarly, starch content in the leaves of NiF4 and Yomitanzan was maintained high, but starch was depleted in Badila leaves after the 52-h exposure. During the chilling temperature, sucrose phosphate synthase (SPS; E.C.2.4.1.14) activity was relatively stable in the leaves of NiF4 and Yomitanzan, whereas in Badila leaves SPS activity significantly decreased. There was no significant change in cytosolic fructose-1,6-bisphosphatase activity for the three cultivars at the chilling temperature. This supports the hypothesis that: (1) on exposure to chilling temperature, sucrose content in sugarcane leaves is determined by the photosynthetic rate in the leaves, and is not related to SPS activity; (2) SPS activity in sugarcane leaves at chilling temperature is to be determined by sugar concentration in the leaves. and Yu-Chun Du, Akihiro Nose.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
274530. Effects of chromium toxicity on leaf photosynthetic characteristics and oxidative changes in wheat (Triticum aestivum L.)
- Creator:
- Subrahmanyam, D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- antioxidants, catalase, ascorbate peroxidase, chlorophyll fluorescence, glutathione reductase, lipid peroxidation, photochemical and non-photochemical quenching, photosystem 2, and superoxide dismutase
- Language:
- Multiple languages
- Description:
- Cr(VI) significantly reduced rates of net photosynthesis and transpiration and of stomatal conductance. Cr(VI) did not affect the Fv/Fm ratio of chlorophyll fluorescence implying that the primary photochemical processes in photosystem 2 were not affected. However, the efficiency of excitation capture by open PS2 centres, in vivo quantum yield of PS2 photochemistry, and electron transport rate were significantly reduced by Cr(VI). The coefficient of photochemical quenching was reduced with a concomitant increase in coefficient of non-photochemical quenching, suggesting reduced demand for ATP and NADPH due to inhibition of CO2 assimilation. Lipid peroxidation was increased by Cr(VI) and the activities of superoxide dismutase and catalase (CAT) were increased. However, the CAT activity was reduced by high Cr(VI) concentration. The activities of ascorbate peroxidase and glutathione reductase were significantly reduced by Cr(VI) treatment.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public