The effects of 0, 30, 60, and 90 mM NaCl, and 0 and 5 mM CaCl2 on certain parameters of photosynthesis and growth in alfalfa (Medicago sativa L. cv. Ghara yonjeh) plants were studied. The increasing NaCl concentration in the Hoagland nutrient solution decreased the contents of chlorophylls and the net photosynthetic rate, and increased the rate of respiration (RD) and CO2 compensation concentration in the leaves of treated plants. The contents of carotenoids (Car) were not significantly affected. The addition of 5 mM CaCl2 enhanced the RD and increased the Car contents in treated leaves. With the NaCl concentration in the culture medium increasing, the dry matter production in both root and shoot decreased, as well as the relative growth rate (RGR), net assimilation rate (NAR), and leaf area ratio (LAR). The addition of CaCl2 caused a partial elimination of the NaCl effects on the root and shoot, RGR and NAR, and it decreased the LAR. and R. A. Khavari-Nejad, N. Chaparzadeh.
The effects of nitroglycerine (NTG) are mediated by liberated nitric oxide (NO) after NTG enzymatic bio-transformation in cells. The aim of this study was to evaluate some products of NTG bio-transformation and their consequences on the redox status of rat erythrocytes and reticulocytes, considering the absence and presence of functional mitochondria in these cells, respectively. Rat erythrocyte and reticulocyte-rich red blood cell (RBC) suspensions were aerobically incubated (2 h, 37 0C) without (control) or in the presence of different concentrations of NTG (0.1, 0.25, 0.5, 1.0 and 1.5 mM). In rat erythrocytes, NTG did not elevate the concentrations of any reactive nitrogen species (RNS). However, NTG robustly increased concentration of methemoglobin (MetHb), suggesting that NTG bio-transformation was primarily connected with hemoglobin (Hb). NTG-induced MetHb formation was followed by the induction of lipid peroxidation. In rat reticulocytes, NTG caused an increase in the levels of nitrite, peroxinitrite, hydrogen peroxide, MetHb and lipid peroxide levels, but it decreased the level of the superoxide anion radical. Millimolar concentrations of NTG caused oxidative damage of both erythrocytes and reticulocytes. These data indicate that two pathways of NTG bio-transformation exist in reticulocytes: one generating RNS and the other connected with Hb (as in erythrocytes). In conclusion, NTG bio-transformation is different in erythrocytes and reticulocytes due to the presence of mitochondria in the latter.
As a common tree species in northern China, Populus × euramericana "Neva" has an important practical value for the study of continuous cropping obstacles in poplar cultivation. Plant allelopathy is the main reason for continuous cropping obstacles, which are caused by allelochemicals, such as para-hydroxybenzoic acid (p-HB). The objective of this study was to investigate the effects of p-HB on the photosynthesis of poplar. Photosynthetic parameters of Populus × euramericana "Neva" poplar were determined in a pot culture experiment where five p-HB concentrations were used (0, 1, 2, 4, and 6 mmol L−1). Each seedling was treated with 4 L of p-HB solution every seven days, ten times in total. p-HB inhibited the photosynthesis of poplar significantly, as shown by a clear decline in the net photosynthetic rate. Our results indicated nonstomatal limitation responsible for the photosynthesis reduction., G. T. Liang, S. Y. Zhang, J. Guo, R. Yang, H. Li, X. C. Fang, G. C. Zhang., and Obsahuje bibliografii
Differences in lipid metabolism of tumor and normal tissues suggest a distinct response to available lipid compounds. In this study, the in vitro effects of five types of commercial parenteral lipid emulsions were investigated on human cell lines derived from normal fetal colon (FHC) or colon adenocarcinoma (HT-29). Changes of the cellular lipid fatty acid content, cell oxidative response, and the cell growth and death rates were evaluated after 48 h. No effects of any type of emulsions were detected on cell proliferation and viability. Compared to the controls, supplementation with lipid emulsions resulted in a multiple increase of linoleic and linolenic acids in total cell lipids, but the content of arachidonic, eicosapentaenoic, and docosahexaenoic acids decreased particularly in HT-29 cells. The concentration of emulsions which did not affected HT-29 cells increased the percentage of floating and subG0/G1 FHC cells probably due to their higher reactive oxygen species production and lipid peroxidation. Co-treatment of cells with antioxidant Trolox reduced the observed effects. Our results imply that lipid emulsions can differently affect the response of colon cells of distinct origin.
We investigated the effect of pertussis toxin (PTX) on hypotensive response induced by acetylcholine (ACh) and bradykinin (BK) and on noradrenaline (NA)-induced pressor response in spontaneously hypertensive rats (SHR). Fifteen-week-old Wistar rats and age-matched SHR were used. Half of SHR received PTX (10 μg/kg/i.v.) and the experiments were performed 48 h later. After the anesthesia the right carotid artery was cannulated in order to record blood pressure (BP). The hypotensive response to ACh was enhanced in SHR compared to Wistar rats. After pretreatment of SHR with PTX the hypotensive response to ACh was reduced compared to untreated SHR and it was also diminished in comparison to Wistar rats. Similarly, the hypotensive response to BK was also decreased after PTX pretreatment. The pressor response to NA was increased in SHR compared to Wistar rats. NA-induced pressor response was considerably decreased after PTX pretreatment compared to untreated SHR. In conclusion, the enhancement of hypotensive and pressor responses in SHR was abolished after PTX pretreatment. Our results suggested that the activation of PTX-sensitive inhibitory Gi proteins is involved in the regulation of integrated vasoactive responses in SHR and PTX pretreatment could be effectively used for modification of BP regulation in this type of experimental hypertension., S. Čačányiová, F. Kristek, J. Kuneš, J. Zicha., and Obsahuje bibliografii a bibliografické odkazy
Populus x euramericana cv. ‘Neva’ is an important tree species in northern China. In the study, we used its potted oneyear- old seedlings as experimental material and established three treatments (CK, 0.5X, and 1.0X) according to the concentrations of phenolic acids in order to examine the effects of different concentrations on the photosynthetic characteristics and growth of poplar. With increasing concentrations of phenolic acids, the net photosynthetic rate, stomatal limitation, transpiration rate, apparent quantum yield, photochemical quenching coefficient, electron transport rate, chlorophyll content, and total biomass decreased significantly. The intercellular CO2 concentration, light-compensation point, nonphotochemical quenching, malondialdehyde content, and root/shoot ratio increased significantly. Peroxidase and superoxide dismutase activities initially decreased and then increased. We concluded that phenolic acids significantly inhibited poplar’s photosynthesis and the higher phenolic acid concentration, the greater inhibition of photosynthesis occurred. This inhibition effect was mainly caused by nonstomatal factors. Phenolic acids induced noticeable photoinhibition, resulted in the irreversible damage of membrane structure, and then changed intracellular metabolic processes. To cope with phenolic acid stress, poplar seedlings increased dissipation of excess light energy and distributed relatively more biomass to underground parts within carbon allocation., D. F. Xie, G. C. Zhang, X. X. Xia, Y. Lang, S. Y. Zhang., and Obsahuje bibliografii
In a previous study, the topsoil and root zone ASCAT satellite soil moisture data were implemented into three multi-objective calibration approaches of the TUW hydrological model in 209 Austrian catchments. This paper examines the model parametrization in those catchments, which in the validation of the dual-layer conceptual semi-distributed model showed improvement in the runoff simulation efficiency compared to the single objective runoff calibration. The runoff simulation efficiency of the three multi-objective approaches was separately considered. Inferences about the specific location and the physiographic properties of the catchments where the inclusion of ASCAT data proved beneficial were made. Improvements were primarily observed in the watersheds with lower slopes (median of the catchment slope less than 15 per cent) and a higher proportion of farming land use (median of the proportion of agricultural land above 20 per cent), as well as in catchments where the runoff is not significantly influenced by snowmelt and glacier runoff. Changes in the mean and variability of the field capacity parameter FC of the soil moisture regime were analysed. The values of FC decreased by 20 per cent on average. Consequently, the catchments’ water balance closure generally improved by the increase in catchment evapotranspiration during the validation period. Improvements in model efficiency could be attributed to better runoff simulation in the spring and autumn month. The findings refine recommendations regarding when hydrological modelling could consider satellite soil moisture data added to runoff signatures in calibration useful.
Total superoxide dismutase (total SOD), copper zinc containing superoxide dismutase (CuZn SOD), and manganese superoxide dismutase (Mn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione- S-transferase (GST) activities as well as ascorbic acid (AsA), and vitamin E (vit E) concentrations were analysed in the liver of rats exposed to cadmium (15 mg Cd/day/kg), selenium (7 fig Se/day/kg), and to cadmium + selenium (15 mg Cd + 7 ptg Se/day/kg), and in control animals. Cadmium caused a decrease of total SOD, Mn SOD, CAT and GSH-Px but an increase of GST activity in the liver of rats. Contrary to cadmium, selenium caused a significant increase of the activity of these enzymes except for GSH-Px. By concomitant exposure to both cadmium and selenium, the toxic effects of cadmium on the activity of mentioned enzymes we abolished. In all exposed groups, the activity of enzyme glutathione-S-transferase was enhanced, indicating its increased role in prevention of lipid peroxidation. Cadmium decreased the concentration of AsA and increased the concentration of vitamin E in the liver, while selenium increased the concentration of both vitamins. However, by concomitant administration of cadmium and selenium, these changes were diminished and tended to reach control values.
A higher mean arterial pressure (MAP) achieved by norepinephrine up-titration may improve organ blood flow in critically ill, whereas norepinephrine-induced afterload rise might worsen myocardial function. Our aim was to assess the effects of norepinephrine dose titration on global hemodynamics in cardiogenic shock. We prospectively evaluated 12 mechanically ventilated euvolemic patients (aged 67±12 years) in cardiogenic shock (10 patients acute myocardial infarction, 1 patient dilated cardiomyopathy, 1 patient decompensated aortic stenosis). Hemodynamic monitoring included arterial and Swan-Ganz catheters. The first data were obtained at MAP of 65 mm Hg, then the norepinephrine dose was increased over 40 min to achieve MAP of 85 mm Hg. Finally, the norepinephrine-dose was tapered over 40 min to achieve MAP of 65 mm Hg. Norepinephrine up-titration increased MAP to the predefined values in all patients with concomitant mild increase in filling pressures and heart rate. Systemic vascular resistance increased, whereas cardiac output remained unchanged. During norepinephrine down-titration, all hemodynamic parameters returned to baseline values. We observed no changes in lactate levels and mixed venous oxygen saturation. Our data suggest that short-term norepinephrine dose up-titration in cardiogenic shock patients treated or pretreated with inotropes was tolerated well by the diseased heart., R. Rokyta, Jr ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The purpose of the present study was to investigate the effect of short-term endurance training on plasma total antioxidant status (TAS) and on in vitro platelet aggregation and ATP release. Blood samples were collected from the abdominal aorta of rats following short-term treadmill exercise (25 m/min, 0 % grade, 30 min) for three consecutive days, as well as in non-exercised control group. Platelet aggregation and platelet ATP release were evaluated by impedance and bioluminescence techniques, respectively. Plasma TAS was measured spectrophotometrically. Plasma TAS was higher and ADP-induced platelet ATP release was lower in the short-term training group with respect to the control group (p<0.001). Significant negative correlation (r = -0.56, p<0.05) was found between plasma TAS and ADP-induced platelet ATP release. Neither ADP- and collagen-induced maximum aggregation rate nor collagen-induced platelet ATP release were significantly different between the groups. According to these results, short-term training caused an alteration in platelet functions limited to the secretion response, which may be related to the oxidant/antioxidant balance changes favoring the antioxidants. The improved plasma total antioxidant capacity was possibly sufficient to prevent exercise-induced oxidative damage, and the adaptive response of platelets might be associated with enhanced antioxidant status.