Arbuscular mycorrhizal fungi (AMF) form symbioses with many plants. Black locust (Robinia pseudoacacia L.) is an important energy tree species that can associate with AMF. We investigated the effects of AMF (Rhizophagus irregularis and Glomus versiforme) on the growth, gas exchange, chlorophyll (Chl) fluorescence, carbon content, and calorific value of black locust seedlings in the greenhouse. The total biomass of the arbuscular mycorrhizal (AM) seedlings was 4 times greater than that of the nonmycorrhizal (NM) seedlings. AMF greatly promoted the photosynthesis of black locust seedlings. AM seedlings had a significantly greater leaf area, higher carboxylation efficiency, Chl content, and net photosynthetic rate (PN) than NM seedlings. AMF also significantly increased the effective photochemical efficiency of PSII and significantly enhanced the carbon content and calorific value of black locust seedlings. Seedlings inoculated with G. versiforme had the largest leaf area and highest biomass, Chl content, PN, and calorific value., X. Q. Zhu, C. Y. Wang, H. Chen, M. Tang., and Obsahuje bibliografii
Atorvastatin and insulin have distinct mechanisms of action to improve endothelial function. Therefore, we hypothesized that atorvastatin and insulin therapies alone or in combination could have beneficial effects on en dothelium-dependent vascular reactivity, oxidative stress, inflammation and metabolic parameters in Goto-Kakizaki (GK) rats, a model of type 2 diabetes fed with atherogenic diet (GKAD). In parallel with the development of diabetes and lipid profile, the generation of oxidative stress was determined by measurement of lipid peroxides and oxidized proteins and the presence of inflammation was evaluated by assessing C-reactive protein (CRP). Additionally, endothe lial dependent and independent vascular sensitivity to acetylcholine and sodium nitroprusside were evaluated. GKAD showed increased carbonyl stress, inflammation, fasting glycemia, dyslipidemia and endothelial dysfunction when compared to control GK rats. Noteworthy, supplementation with insulin deteriorated endothelial dysfunction while atorvastatin induced an improvement. Atorvastatin and insulin therapies in combination improved metabolic parameters, CRP levels and insulin resistance indexes and ameliorated endothelial dysfunction in GKAD rats while they were unable to reduce urinary 8-isoprostranes and plasma carbonyl compounds. The therapeutic association of atorvastatin and insulin provided a better metabolic control with a reduction in endothelial dysfunction in GKAD rats by a mechanism that involves an improvement in systemic inflammation., C. M. Sena ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Atrial natriuretic peptide antifibrotic properties are mainly described in cardiac myocytes or in induced cardiac myofibroblasts (Angiotensin II or TGF-β induced differentiation). In the present work, we investigate the effects of ANP/NPRA/cGMP system in modulating rat cardiac fibroblasts function. Cardiac fibroblasts were isolated from adult Wistar male rats and cultured in the presence of serum in order to induce fibroblasts differentiation. Cultures were then treated with ANP (1 μM), 8-Br-cGMP (100 μM) or IBMX (100 μM), a non-specific phosphodiesterases inhibitor. ANP significantly decreased proliferation rate and collagen secretion. Its effect was mimicked by t he c GMP a nalog, w hile c ombining A NP w ith 8 -Br-cGMP did not lead to additional effects. Moreover intracellular cGMP levels were elevated when cells were incubated with ANP confirming that ANP intracellular pathway is mediated by cGMP. Additionally, immunoblotting and immunofluorescence were used to confirm the presence of guanylyl cyclase specific natriuretic peptide receptors A and B. Finally we scanned specific cGMP dependent PDEs via RT-qPCR, and noticed that inhibiting all PDEs led to an important decrease in proliferation rate. Effect of ANP became more prominent after 10 culture days, confirming the importance of ANP in fibroblasts to myofibroblasts differentiation. Uncovering cellular aspects of ANP/NPRA/cGMP signaling system provided more elements to help understand cardiac fibrotic process., M. Moubarak, C. Magaud, Y. Saliba, A. Chatelier, P. Bois, J.-F. Faivre, N. Farès., and Obsahuje bibliografii
Various types of mechanosensitive ion channels, including cationic stretch-activated channels (SAC NS ) and stretch-activated BKca (SAKca) channels, modulate heart rhythm. Bepridil has been used as an antiarrhythmic drug with multiple pharmacological effects; however, whether it is effective for mechanically induced arrhythmia has not been well investigated. To test the effects of Bepridil on SAKca channels activity, cultured chick embryo nic ventricular myocytes were used for single - channel recordings. Bepridil significantly reduced the open probability of the SAKca channel (PO). Next, to test the effects of bepridil on stretch-induced extrasystoles (SIE), we used an isolated 2-week-old Langendorff-perfused chick heart. The left ventricle (LV) volume was rapidly changed, and the probability of SIE was calculated in the presence and absence of bepridil, and the effect of the drug was compared with that of Gadolinium (Gd3+). Bepridil decreased the probability of SIE despite its suppressive effects on SAKca channel activity. The effects of Gd3+, which blocks both SAKca and SACNS , on the probability of SIE were the same as those of bepridil. Our results suggest that bepridil blocks not only SAKc a channels but possibly also blocks SACNS , and thus decreases the stretch -induced cation influx (stabilizing membrane potential) to compensate and override the effects of the decrease in outward SAKca current (destabilizing membrane potential)., H. Jin, G. Iribe, K. Naruse., and Obsahuje bibliografii
Beta-hydroxy-beta-methylbutyrate (HMB) is a leucine metabolite with protein anabolic effects. Since HMB is synthesized in the liver, unique effects of exogenous HMB intake may be hypothesized in subjects with liver disease, in which muscle wasting is frequently found. We studied effects of HMB on the liver and soleus (SOL) and extensor digitorum longus (EDL) muscles in partially-hepatectomized (PH) rats. HMB or saline was infused using osmotic pumps to PH or sham-operated rats for 7 days. We found lower body weight and protein content in EDL of PH rats treated with saline than in sham-operated animals. These effects were insignificant in HMB treated animals. In blood plasma of PH rats treated with HMB we found lower concentrations of creatinine and higher concentrations of urea and branched-chain amino acids (BCAA; valine, leucine, and isoleucine) than in PH animals treated with saline. HMB increased BCAA concentrations in SOL and EDL of PH animals and decreased proteolysis in EDL of both sham-operated and PH animals. In the livers of PH rats treated with HMB we found higher DNA content, DNA fragmentation, and BCAA concentrations than in saline-treated animals. The results indicate that HMB affects metabolism of BCAA and has positive influence on protein balance in muscles. Further studies are needed to clarify the effect of HMB on liver regeneration., M. Holeček, M. Vodeničarovová., and Obsahuje bibliografii
The aim of this study was to explore the changes in the adipokines leptin and adiponectin in obese patients with type 1 diabetes mellitus (T1DM) who underwent seven days of fasting and 21 days of low-calorie diet (LCD). The plasma leptin and adiponectin concentrations were measured in 14 obese patients with T1DM at baseline, immediately after 7 days of fasting, and after 21 days of LCD. 13 non-obese patients with T1DM were studied only after an overnight fasting. Bioimpedance technique was used for determination of body composition. Obese T1DM patients lost 6.0 kg (6.0; 6.8) (median, 25 %; 75 %) and decreased their fat tissue after fasting and LCD. Plasma leptin in obese T1DM was significantly higher than in non-obese T1DM patients: 9.10 (5.06; 25.89) vs. 1.71 (1.12; 7.08) μg ∙ l-1 and transiently decreased immediately after fasting: 3.45 μg ∙ l-1 (1.47; 7.00), (P<0.05). Adiponectin/leptin ratio in obese T1DM was significantly lower than in non-obese T1DM patients: 0.67 (0.57; 1.49) vs. 3.50 (2.46; 6.30) ∙ 103 and transiently increased immediately after fasting: 2.22 (1.26; 3.24) ∙ 103, (P<0.05). We conclude that obese patients with T1DM are characterized by hyperleptinemia that is reduced by prolonged fasting, but only slightly affected by low calorie diet., F. Musil, V. Blaha, A. Ticha, R. Hyspler, M. Haluzik, J. Lesna, A. Smahelova, L. Sobotka., and Obsahuje bibliografii
Brassinosteroids (BRs) have been reported to counteract various stresses. We investigated effects of exogenously applied brassinosteroid, 24-epibrassinolide (EBR), and brassinosteroid-mimic compound, 7,8-dihydro-8α-20-hydroxyecdysone (DHECD), on the photosynthetic efficiency and yield of rice (Oryza sativa L. cv. Pathum Thani 1) under heat stress. Solutions (1 nM) of EBR and DHECD were separately sprayed onto foliage of individual rice plants during their reproductive stage. Five days after the application, the plants were transferred to the day/night temperature regime of 40/30°C for 7 days and then allowed to recover at normal temperature for 7 days. We demonstrated that both DHECD and EBR helped maintain the net photosynthetic rate. The DHECD and EBR application enhanced stomatal conductance, stomatal limitation, and water-use efficiency under the high-temperature regime. DHECD- and EBR-treated plants showed an increase in the nonphotochemical quenching that was lower than that in the control plants. Moreover, DHECD and EBR treatments maintained the maximal quantum efficiency of PSII photochemistry and the efficiency of excitation capture of the open PSII center. Furthermore, the treatments with DHECD or EBR resulted in higher chlorophyll content during the heat treatment compared with the control plants. The paddy field application of 1 nM EBR and/or 1 nM DHECD at the reproductive stage during the hot season could increase the rice yield, especially, the number of filled seeds. DHECD and EBR enhanced total soluble sugar and reducing sugar in straw and more starch was accumulated in rice seeds. Consequently, our results confirmed that DHECD showed biological activities mimicking EBR in the improvement of photosynthetic efficiency and in rising the rice yield under heat stress., J. Thussagunpanit, K. Jutamanee, W. Sonjaroon, L. Kaveeta,
W. Chai-Arree, P. Pankean, A. Suksamrarn., and Obsahuje bibliografii
Ca2+ is an important factor mediating many biotic and abiotic stress responses in plants. In this study, we measured the chlorophyll (Chl) fluorescence of transgenic rice with increased or decreased expression of a calcium-sensing receptor (OsCaS) gene during water deficit caused by polyethylene glycol to prove our hypothesis that increased Ca2+ in combination with increased OsCaS could enhance the drought resistance of transgenic rice. Transcript abundance (evaluated by RT-PCR) was significantly lower in OsCaS antisense line 766 (AS766) than that in the wild type, while the overexpression line 777 (O777) showed four times higher amount than that in the wild type. Chl fluorescence showed that the photochemical quantum yield of PSII in the light increased due to addition of Ca2+ in the O777, but dropped in the AS766. Nonphotochemical quenching increased under stress in both transgenic lines and in the wild type, but less in the O777. Nonregulatory quantum yield of energy dissipation showed no significant change under drought stress. Photochemical quenching was significantly higher in the O777 than those in the AS766 and in the wild type after the Ca2+ treatment. In the absence of stress, the electron transport rate (ETR) was significantly higher in the O777 than in both the AS766 and the wild type. In contrast, the ETR of the wild type and both transgenic lines decreased under drought stress, while the effect of polyethylene glycol was partially alleviated by Ca2+ addition in the O777. In summary, excitation energy conversion and dissipation by PSII were regulated by Ca2+ in the O777. It might partially alleviate the effect of drought stress, whereas addition of Ca2+ had no effect in the wild type and the AS766., R. Wei, Y. Liu, Y. Sui, M. Xu, S. Liu, X. Zhao., and Obsahuje seznam literatury
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
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.