High irradiance promotes decreases in the quantum yield in plants, which reduce the photosynthetic rate. The excess of light in combination with water deficit can intensify the response of plants to stress, especially in species susceptible to those factors. The aim of the present study was to characterize the photosynthetic activity of young jatobá-do-cerrado (Hymenaea stigonocarpa Mart. ex Hayne) trees under different irradiance conditions, both alone and/or in combination with water deficit. Four irradiances [45, 230, 510, and 1,700 μmol(photon) m-2 s-1] and two levels of water in soil (90% and 50% of field capacity) were used. Gas exchange, water potential, and chlorophyll a fluorescence were measured. The highest rates of photosynthesis were observed under irradiances of 230 and 510 μmol(photon) m-2 s-1. Irradiance of 1,700 μmol(photon) m-2 s-1 led to the photoinhibition of photosynthesis, as indicated by a reduced maximum quantum yield of PSII, effective quantum yield ratio, and electron transport rate, as well as higher nonphotochemical quenching. The most stressful to young H. stigonocarpa plants was high irradiance, while water deficit did not intensify the response to light stress., A. C. Costa, S. L. Rezende-Silva, C. A. Megguer, L. M. F. Moura, M. Rosa, A. A. Silva., and Obsahuje bibliografii
This study aimed to investigate alterations in hemorheology induced by L-carnosine, an anti- oxidant dipeptide, and to determine their relationship to oxidative stress in density-separated erythrocytes of aged and young rats. 28 male Sprague Dawley rats were divided into 4 groups as aged (Aca), young (Yca) L-carnosine groups (250 mg/kg L-carnosine, i.p.) and aged (As), young (Ys) control groups (saline, i.p.). Density separation was further performed to these groups in order to separate erythrocytes according to their age. Blood samples were used for the determination of erythrocyte deformability, aggregation; and oxidative stress parameters. Erythrocyte deformability of Yca group measured at 0.53 Pa was lower than Aca group. Similarly, deformability of least-dense (young) erythrocytes of Yca group was decreased compared to least-dense erythrocytes of Aca groups. Total antioxidant capacity (TAC) of Aca group was higher and oxidative stress index (OSI) lower than As group. Although L-carnosine resulted in an enhancement in TAC of aged rats, this favorable effect was not observed in erythrocyte deformability and aggregation in the dose applied in this study. and G. Erken, M. Bor-Kucukatay, E. KilicToprak, B. Akdag, V. Kucukatay
Fat-enriched diet is strongly associated with cataract development. Laurus nobilis shows antioxidant activity. Herein we evaluated the effect of Laurus nobilis oral administration on the blood and lenses antioxidant activity in rabbits under fat-enriched diet. Sixty rabbits divided into 4 groups were used. One group represented the control (N-CTR). The second group (P-CTR) fed a diet supplemented with 2.5 % of pig fat; the third group (EXP1) received a diet supplemented with 2.5 % of pig fat and 1 g/kg of dried-bay leaves; the fourth group (EXP2) was treated with dried-bay leaves at the rate of 1 g/kg of feed. At baseline and at the end of the study (56 days) the following blood parameters were determined: thiobarbituric acid reactive substances (TBARS), reactive oxygen metabolites (ROMs), total phenols, superoxide dismutase (SOD), oxygen radical absorbance capacity (ORACpca), ferric ion reducing antioxidant power (FRAP), retinol and alfa-tocopherol. At the end of the follow-up, the eyes were enucleated and the antioxidant profile, such as total antioxidant activity (TAC), TBARS, retinol and alfa-tocopherol of lenses was evaluated. Plasma ROMs and TBARS levels were statistically lower in the groups receiving bay leaves integration. A significant increase of plasma retinol, FRAP and ORACpca levels was found in EXP1 and EXP2 groups, whereas plasma alfa-tocopherol resulted statistically higher only in EXP2 group. Bay leaves supplementation enhanced TAC, retinol and alfa-tocopherol in rabbit lens, particularly in EXP2 group; whereas lenses TBARS levels significantly decreased in both treated groups. These findings demonstrate that Laurus nobilis oral administration exerts a protective effect on the risk of cataract development in rabbits under fat-enriched diet., D. Casamassima, F. Chiosi, F. Vizzarri, M. Palazzo, C. Costagliola., and Obsahuje bibliografii
After a S-d cultivatíon in Solutions of different concentrations of lead and copper, structiiral changes were established in the photosynthetic apparatus of Elodea canadensis Rich. Lead and low concentrations of copper (0.03, 0.06 and 0.25 g m’^) did not induce large structural transformations in the protoplast. Some of the changes were specific for the species; vacuolization of the cytoplasm, instability of the tonoplast, increased activity of the dictyosomes, abnormally active division of the mitochondria, and number of chloroplasts and mitochondria in definite cell zones. High concentrations of copper (0.5, 1 and 1.5 g m*^) induced within 5 d a generál destruction of the protoplast. The concentration of 0.5 g(Cu^0 threshold concentration for survival of this species. High quantities of both metals were accumulated in the treated plants.
Leptin, a cytokine-like hormone secreted by adipocytes, is known to regulate food intake but has also emerged as a significant factor in the regulation of bone mass. In humans, states of energy deprivation with low serum leptin have been associated with low bone mass. In mice, leptin deficiency led to increased trabecular bone mass with overall decrease in cortical bone. Leptin regulates bone metabolism indirectly in the hypothalamus thereby activating the sympathetic nervous system (SNS). In addition to the SNS, leptin also interacts with various hypothalamic neuropeptides, such as cocaine- and amphetamine-regulated transcript, neuropeptide Y and/or neuromedin U, which might modulate the effects of leptin on bone. In osteoblasts sympathetic signaling is further gated by the transcriptional factors called molecular clock. As a result, bone loss is accelerated showing that the central effect of leptin seems to be antiosteogenic. Additionally, leptin has a direct anabolic effect within the bone driving the differentiation of bone marrow stem cells into the osteoblastic cell lineage. Besides the interaction between the central and peripheral pathways, the overall effect of leptin on bone might be bimodal depending on leptin serum concentrations. Regulatory pathways triggering osteoblast activity might open new possibilities for anabolic treatment of osteoporosis., V. Cirmanová, M. Bayer, L. Stárka, K. Zajíčková., and Obsahuje bibliografii a bibliografické odkazy
This study was designed to investigate effect of alpha-lipoic acid (LA) on lipid peroxidation, nitric oxide production and antioxidant systems in rats exposed to chronic restraint stress. Twenty four male Wistar rats, aged three months, were divided into four groups: control (C), the group treated with LA (L), the group exposed to restraint stress (S) and the group exposed to stress and treated with LA (LS). Restraint stress was applied for 21 days (1 h/day) and LA (100 mg/kg/day) was injected intraperitonally to the L and LS groups for the same period. Restraint stress significantly decreased brain copper/zinc superoxide dismutase (Cu,Zn-SOD) and brain and retina glutathione peroxidase (GSH-Px) and catalase (CAT) activities compared with the control group. Thiobarbituric acid reactive substances (TBARS), nitrite and nitrate levels were significantly increased in the tissues of the S group compared with the C group. LA produced a significant decrease in brain and retina TBARS, nitrite and nitrate levels of the L and LS groups compared to their corresponding control groups. LA increased all enzyme activities in the tissues of the LS group compared to the S group. Our study indicated that LA is an ideal antioxidant candidate for the prevention of stress-induced lipid peroxidation., D. Akpinar, P. Yargiçoğlu, N. Derin, Y. Alicigüzel, A. Ağar., and Obsahuje bibliografii a bibliografické odkazy
Hemorrhagic shock (HS) represents an acute event with high mortality. The optimal combination of anesthetics that would prevent hemodynamic collapse and allow damage control surgery has not yet been determined. We tested the hypothesis that a combination of dissociative anesthetic ketamine with alpha2- agonist medetomidine (MK group, n=10) would provide superior hemodynamic control compared to propofol-remifentanil (PR group, n=10) during HS in minipigs. A modified Wiggers‘ model of HS with a target mean arterial pressure (MAP) of 40 mm Hg and 2 h duration was used. All minipigs survived. HS led to a ~50 % decrease in cardiac output in both groups (P<0.001 for baseline vs. HS 120 min) with no differences between groups. Total volume of removed blood was larger in the MK group (1321±133 ml vs. 1111±246 ml in the PR group, respectively; P<0.05). MAP was higher during the initial phases of HS in the MK group than in PR group (P<0.05 at HS 30-90 min). HR was lower in the MK group at the late phases of HS (P<0.05 at HS 60-120 min). In conclusion, medetomidine-ketamine provides a feasible and possibly a more favorable alternative to the propofol-remifentanil combination in our model of HS in minipigs., A. Brezina ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Současné studie naznačují možnou důležitou úlohu melatoninu v Huntingtonově nemoci (HN) a jeho možné terapeutické využití při léčbě této nemoci. HN je dědičné neurodegenerativní onemocnění, které doprovází snižování hladiny melatoninu s postupem onemocnění. U normálních (nenádorových) buněk působí melatonin antiapoptoticky díky svým antioxidačním vlastnostem a schopnosti zabránit aktivaci proteinu p53. Dále melatonin zvyšuje expresi BDNF (brain derived neurotrophic factor) a dalších neuroprotektivních faktorů. Cílem této studie bylo stanovit netoxickou dávku melatoninu pro primární kožní fibroblasty izolované z transgenních miniprasat pro N‑koncovou část lidského mutovaného huntingtinu (TgHD) a popsat efekt tohoto ošetření na tyto buňky vystavené genotoxickému stresu. Buňky byly kultivovány v médiu obohaceném různými dávkami melatoninu. Analýzou proliferačních křivek získaných mikroskopováním živých buněk v pravidelných časových intervalech jsme stanovili efekt různých koncentrací melatoninu.Ukázali jsme, že vyšší dávky melatoninu jsou pro primární prasečí buňky toxické. Je zajímavé, že TgHD buňky byly oproti kontrolním buňkám více citlivé k tímto dávkám melatoninu. Stanovili jsme efektivní dávku melatoninu a současně jsme ukázali její efekt na proliferaci u buněk vystavených genotoxickému stresu. Klíčová slova: Huntingtonova choroba – melatonin – mikroskopie buněk v čase – miniprasečí model –proliferační křivky – kožní fibroblasty Autoři deklarují, že v souvislosti s předmětem studie nemají žádné komerční zájmy. Redakční rada potvrzuje, že rukopis práce splnil ICMJE kritéria pro publikace zasílané do biomedicínských časopisů., According to the recent studies, melatonin might play an important role in Huntington’s disease (HD) and act as a novel therapeutic approach in the treatment of the disease. HD, the inherited neurodegenerative disorder, is accompanied by gradual melatonin reduction as it progresses. Melatonin in normal cells (non‑tumor) has the anti‑apoptotic ability due to its antioxidant property and its ability to prevent the activation of p53. Furthermore, melatonin increases the expression of BDNF (brain derived neurotrophic factor) and other neuroprotective factors. The aim of this study was to evaluate the nontoxic dose of melatonin for primary skin fibroblasts isolated from minipigs transgenic for the N‑terminal part of human mutated huntingtin (TgHD), and the effect of melatonin treatment to these cells exposed to genotoxic stress. Cells were cultured in medium supplemented with different doses of melatonin. Using time lapse microscopy, we estimated the effect of decreasing melatonin concentrations by analyzing the proliferation curves. We show that higher doses of melatonin are toxic for primary porcine fibroblasts. Interestingly, TgHD cells were more sensitive to these doses of melatonin treatment than wild type cells. We evaluated the effective dose of melatonin and demonstrated its rescue proliferative effect on porcine primary cells exposed to genotoxic stress., and P. Rausova, J. Valasek, Z. Ellederová, J. Motlik
Water availability is the main factor limiting crop growth and productivity in dry regions. This study was carried out in order to determine the effect of spraying methanol solution on the photosynthetic characteristics of bean plants. The main aim of our experiment was to improve plant performance under stress caused by water shortage. Two factors were involved: water-deficit stress, such as severe stress (25% of field capacity), mild stress (75% of field capacity), and no stress (100% of field capacity), and application of methanol solution spray at four concentrations: control (without spraying), 10, 20, and 30%. Methanol was applied three times at different growth stages (seedling, flowering, and podding stage) in 10-d intervals. The treatment with 20% methanol at the seedling stage resulted in increased net photosynthesis (P N), intercellular CO2 concentration (C i), and decreased transpiration rate (E) under no stress and mild stress conditions. Under severe stress, 10 and 20%-methanol treatments resulted in increased C i, maximal quantum yield of PSII photochemistry, and decreased E. At the flowering stage, methanol treatments resulted in decreased E and increased C i under mild and severe stress. At the podding stage, 10 and 20%-methanol treatments resulted in increased P N, C i, and total chlorophyll content under mild stress. In conclusion, we suggested that foliar application of methanol had a positive role in enhancing photosynthetic performance., N. Armand, H. Amiri, A. Ismaili., and Obsahuje seznam literatury
Type 2 diabetes (T2D) as well as cardiovascular disease (CVD) represent major complications of obesity and associated metabolic disorders (metabolic sy ndrome). This review focuses on the effects of long-chain n-3 polyunsaturated fatty acids (omega-3) on insulin sensitivity and glucose homeostasis, which are improved by omega-3 in many animal models of metabolic syndrome, but remain frequently unaffected in humans. Here we focus on: (i) mechanistic aspects of omega-3 action, reflecting also our experiments in dietar y obese mice; and (ii) recent studies analysing omega-3’s effects in various categories of human subjects. Most animal experiments document beneficial effects of omega-3 on insulin sensitivity and glucose metabolism even under conditions of established obesity and insulin resistance. Besides positive results obtained in both cross- sectional and prospective cohort studies on healthy human populations, also some intervention studies in prediabetic subjects document amelioration of impaired glucose homeostasis by omega-3. However, the use of omega-3 to reduce a risk of new-onset diabetes in prediabetic subjects still remains to be further characterized. The results of a majority of clinical trials performed in T2D patients suggest that omega-3 have none or marginal effects on metabolic control, while effectively reducing hypertriglyceridemia in these pati ents. Despite most of the recent randomized clinical trials do not support the role of omega-3 in secondary prevention of CVD, this issue remains still controversial. Combined interventions using omega-3 and antidiabetic or hypolipidemic drugs should be further explored and considered for treatment of patients with T2D and other diseases., P. Flachs, M. Rossmeisl, J. Kopecky., and Obsahuje bibliografii a bibliografické odkazy