Different light filters affect leaf photosynthetic features and fruit quality. Consequently, selecting the appropriate covering filter for rain-shelter cultivation of peaches is a key part of successful production. We used a late-maturing peach variety ‘Xiahui 8’ to study differences in leaf photosynthetic features, chlorophyll fluorescence characteristics, and fruit quality under neutral, red, yellow, green, and blue filter, with natural light as control. The results showed that the leaf photosynthetic ability and internal quality under the neutral filter treatment were elevated compared with the control, and the appearance color was the same as the control. Leaves under neutral filter could maintain higher photosynthetic ability than other filter treatments. In addition, the fruits could also keep higher quality when treated with neutral filter. Therefore, the application of neutral filter in rain-shelter cultivation of ‘Xinhui 8’ peaches is recommended for maintaining high photosynthetic capacity and for improving fruit quality., B.-B. Zhang, J.-L. Xu, M. Zhou, D.-H. Yan, R.-J. Ma., and Obsahuje bibliografii
The effects of liposomal muramyl tripeptide phosphatidylethanolamine (MTP-PE/MLV, radioprotective immunomodulator; 10 mg/kg) and indomethacin (INDO, inhibitor of prostaglandin production; 2 mg/kg) on post-irradiation recovery of hematopoietic functions in mice were investigated. Two agents with distinct radioprotective mechanisms were administered alone or in combination 24 h and 3 h before exposure to 7 Gy 60Co radiation. In the post-irradiation period (3-14 days) combined pre-treatment of mice accelerated recovery of bone marrow cellularity, weight of spleen and myelopoietic and erythropoietic activity in both hematopoietic organs, compared to treatment with MTP-PE/MLV or indomethacin alone. In the peripheral blood, improved radioprotective effects of combined drug administration were found in the recovery of reticulocytes and platelet count. No further significant differences in the recovery of leukocyte count were observed in the examined groups until post-irradiation day 14. Within the first 3-6 post-irradiation days, the bone marrow and peripheral blood smears of mice pre-treated with indomethacin alone or its combination with MTP-PE/MLV more frequently featured blast cells and large cells with abundant cytoplasm which could be considered the hematopoietic stem cells., N. O. Macková, P. Fedoročko., and Obsahuje bibliografii
The aims of our study were to investigate into the effect of lithium on smooth muscle contraction and phosphorylation of myosin light chain (MLC20) by MLCK and to find out the clue of its mechanism. Isolated rabbit duodenum smooth muscle strips were used to study the effects of lithium on their contractile activity under the condition of Krebs’ solution by means of HW-400S constant temperature smooth muscle trough. Myosin and MLCK were purified from the chicken gizzard smooth muscle. Myosin phosphorylation was determined by Glycerol-PAGE, myosin Mg2+-ATPase activity was measured by Pi liberation method. Lithium (10-40 mM) inhibited the contraction in duodenum in a dose-related and time-dependent manner. Lithium could also inhibit the extent of myosin phosphorylation in a dose-related and time-dependent manner, whereas it inhibited Mg2+-ATPase activity in a dose-rel ated manner. Lithium inhibited smooth muscle contraction by inhibition of myosin phosphorylation and Mg2+-ATPase activity., Z. Y. Tang, Z. N. Liu, L. Fu, D. P. Chen, Q. D. Ai, Y. Lin., and Obsahuje bibliografii
Today, the use of waste tires mixed with soil has been expanded in various geotechnical projects to absorb and reduce the vibration caused by seismic and dynamic loads. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, 1-g shaking table tests were carried out, and the effects of important parameter like loading frequency on the dynamic behavior of mixtures were investigated. Tire powders were added to the sand with 5%, 10%, 15% and 20% in gravimetric basis and with a relative density of zero were subjected to sinusoidal loading at frequencies of 0.5, 1, 2, 3, 5, 7 and 9 Hz and input acceleration of 0.1g and 0.3g. The results showed that in all cases, the increase in frequency in the same cycles increased the shear modulus and the damping ratio. Also, with increasing shear strain, the shear modulus of the mixture decreased, but the damping ratio increased. On the other hand, by increasing the tire powder, the value of the shear modulus is reduced, but the amount of damping ratio is increased.
The effect of two elevated carbon dioxide concentrations, 700 µmol(CO2) mol-1 (C700) and 1 400 µmol(CO2) mol-1 (C1400), on photosynthetic performances of 1-year-old Prunus avium L. plant was studied. Plants grown at C700 were characterised by increased net photosynthetic rate (PN) as compared to those grown at C1400. Plant photosynthetic adjustment to C1400 resulted in 27 % higher PN than in control at atmospheric CO2 concentration (Ca) at the beginning of the experiment (3-4 weeks) with a consequent decline to the end of the experiment. Thus, 1 400 µmol(CO2) mol-1 had short-term stimulatory effect on plant PN. Both chlorophyll (Chl) a and b concentrations dramatically decreased during exposure to C1400. Compensation irradiance was increased by 57 % in C700 and by 87 % in C1400. Photochemical efficiency (φ) was affected by balloon environment, however, a clear stimulatory effect of C700 was detected. Opposite influence of both elevated CO2 concentrations on PNmax was established: slight increase by C700 (2.7 % at Ca), but considerable decrease by C1400 (63 % at Ca). Exposure to C700 enhanced compensation irradiance by 42 %, while C1400 by only 21 %. Either C700 or C1400 did not reduce stomatal conductance (gs). Leaf area per plant (LAR) was more stimulated by C700 than by C1400. High unit area leaf mass, specific leaf area, and dry matter accumulation in roots without affecting tissue density characterised plants grown in C1400. However, when considering the root : shoot ratio, these plants allocated less carbon to the roots than plants from other treatments.
The effect of 4 weeks’ inhibition of NO synthase by nitro-L-arginine methyl ester (L-NAME) on haemodynamic parameters and cGMP and cAMP content was studied in rat tissues. L-NAME in both 20 mg/kg/day and 40 mg/kg/day doses significantly increased systolic blood pressure by 28 % and 30 % and decreased the heart rate by 14 % and 23 %, respectively, after the first week. These changes persisted during the following three weeks. Left ventricular weight/body weight (LVW/BW) ratio was significantly elevated in both L-NAME-treated groups by 19 % and 29 %, respectively. Radioimmunoassay was used to determine the cGMP and cAMP content Cyclic GMP content in animals treated by L-NAME (20 mg/kg/day and 40 mg/kg/day) decreased significantly by 13 % and 22 % in the left ventricle, by 28 % and 62 % in the aorta, by 20 % and 34 % in the brain, and by 10 % and 15 % in the kidney, respectively. On the other hand, the cAMP content increased in both L-NAME treated groups by 8 % and 9 % in the left ventricle, by 28 % and 46 % in the aorta, and by 23 % and 32 % in the brain, respectively. There were no significant changes in kidney cAMP content as compared to control animals. The results suggest a simultaneous decrease of cGMP and increase of cAMP content in the majority of studied tissues during NO-deficient hypertension.
The aim of this study was to investigate the effects of long-term stay of Japanese quail in simulated microgravity on some sexual features of males. As a model for simulating microgravity exposure of birds in laboratory conditions was used hypodynamia. The mean left testis weight in males reared under hypodynamia from day 3 up to 180 days of age was lower than that of control (P<0.05), but the right testis weight differences between both groups were not significant. Also the area, volume and foam production of cloacal gland was not significantly decreased in hypodynamia birds at the end of experiment. By contrast, the plasma testosterone concentration of males living in hypodynamia was reduced about 50 % at 90 and 180 days of age in comparison to control (P<0.05) suggesting some negative effects on sexual development. Our results demonstrated that male quail kept under simulated microgravity conditions were sexually competent although their sexual efficiency was reduced especially in terms of plasma testosterone., P. Škrobánek ... [et al.]., and Obsahuje seznam literatury
We studied the effect of losartan on baroreflex sensitivity (BRS) and heart rate variability (HRV) of adult Wistar rats during acute and chronic inhibition of nitric oxide synthesis by NG -nitro-Larginine methyl ester (L-NAME). Chronic L-NAME administration (50 mg/kg per day for 7 days, orally through gavage) increased mean arterial pressure (MAP), heart rate but significantly decreased BRS. In addition, a significant fall of standard deviation of normal RR intervals, total spectral power, high frequency spectral power and a rise of low frequency to high frequency (LF: HF) ratio was seen. Acute L-NAME administration (30 mg/kg, i.v. bolus dose) also raised MAP and impaired HRV but it was associated with augmented BRS for bradycardia reflex. Losartan treatment (10 mg/kg, i.v.) in both acute and chronic L-NAME treated rats, decreased MAP but the difference was not significant. On the other hand, losartan administration normalized depressed BRS for bradycardia reflex and significantly reduced LF to HF ratio in chronic L-NAME treated rats. But this improvement was not observed in acute L-NAME group. These results indicate importance of mechanisms other than renin-angiotensin system in the pressor response of both acute as well as chronic L-NAME. However, autonomic dysregulation especially following chronic L-NAME appears to be partly angiotensin dependent., M. Chaswal ... [et al.]., and Obsahuje seznam literatury
The survival of Encephalitozoon cuniculi Lcvaditi, Nicolau et Schoen, 1923 spores suspended in distilled water and exposed at defined temperatures was investigated. Infectivity of E. cuniculi spores was tested by inoculation of SCID mice. There was no marked loss of infectivity of spores stored at 4°C for two years or frozen at -12°C and -24°C for 1, 8, and 24 h. Although there was a remarkable loss of infectivity, spores remained infective after freezing at -70°C for 1 and 8 h. Heating at 60°C and 70°C for 5 min and 1 min, respectively, rendered the microsporidia non-infective. These findings demonstrate that E. cuniculi spores suspended in water can survive freezing temperatures but lost infectivity in water that reached a temperature of 60°C at 5 min.
Obesity in T1DM patients is associated with the components of metabolic syndrome. The influence of controlled fasting and low calorie diet (LCD) on insulin sensitivity and glucose metabolism was studied in 14 obese patients with type 1 diabetes mellitus (T1DM) (42.6±9.4 years, BMI 32.4±2.1 kg m−2). Insulin sensitivity in obese T1DM patients was measured using a hyperinsulinemic-euglycemic clamp before fasting, immediately after 7 days of fasting, and after 21 days of LCD. Glucose oxidation and non-oxidative glucose disposal were measured before and during the clamp by indirect calorimetry. In the control group of 13 of non-obese T1DM patients (36.9±13.9 years, BMI 22.6±2.1 kg m−2), only one hyperinsulinemiceuglycemic clamp was performed. Obese T1DM patients lost 6.1±1.1 kg after fasting and maintained reduction in body weight after 21 days of LCD. Fasting transiently reduced insulinmediated glucose disposal in the clamp (from 9.69±1.48 to 6.78±1.21 mg min−1 kg−1, P<0.001). This was caused by reduced glucose oxidation after the fasting period (from 2.81±0.52 to 0.88±0.98 mg min−1 kg−1, P<0.001). We conclude that one week of fasting transiently decreased insulin-mediated glucose disposal in T1DM patients. This was caused by reduced glucose oxidation., F. Musil, ... [et al.]., and Obsahuje seznam literatury