In order to study photosynthetic characteristics, phosphoenolpyruvate carboxylase (PEPC) and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activities as well as soluble protein and chlorophyll contents were determined in leaf and fruit pericarp samples from diverse coffee genotypes (Coffea arabica cv. Colombia, Caturra, Caturra Erecta, San Pacho, Tipica, C. stenophylla, C. eugenioides, C. congensis, C. canephora, C. canephora cv. Arabusta, C. arabica cv. Caturra×C. canephora and Hibrido de Timor. We found a slightly higher PEPC activity in fruit pericarp than in leaves, while RuBPCO activity was much lower in pericarp than leaf tissue. Partial purification of PEPC and RuBPCO was carried out from leaves of C. arabica cv. Caturra and Michaelis-Menten kinetics for RuBPCO (Km CO2 = 5.34 µM), (Km RuBP = 9.09 µM) and PEPC (Km PEP = 19.5 µM) were determined. Leaf tissues of Colombia, Hibrido de Timor, and Caturra consistently showed higher content of protein [55.4-64.4 g kg-1 (f.m.)] than San Pacho, C. stenophylla, Tipica, Caturra Erecta, and Caturra×C. canephora [25.6-36.9 g kg-1 (f.m.)] and C. canephora cv. Arabusta, Borbon, C. congensis, C. eugenioides, and C. canephora [16.1-21.1 g kg-1 (f.m.)]. and Y. Lopez ... [et al.].
Four groups of goldfish were exposed to cadmium in a concentration of 20 mg Cd/l water under aquarium conditions. The duration of exposure was 1, 4, 7 and 15 days. It was shown that the activity of superoxide dismutase (SOD) in the red blood cells (RBC) significantly decreased after the first day of cadmium exposure. However, the SOD activity increased after 7 and 15 days of cadmium treatment. Elevated activity of catalase (CAT) was found in erythrocytes of cadmium-treated fishes after 15 days, whereas plasma GOT levels was increased after 7 and 15 days and GPT levels after 1, 4, 7 and 15 days of cadmium treatment. This was accompanied by a significant decrease of blood hemoglobin concentrations (after 15 days) and hematocrit values (after 7 and 15 days). However, the concentration of blood glucose significantly increased after 1, 4, 7 and 15 days of cadmium exposure. These results indicate that cadmium causes oxidative stress and tissue damage in the exposed fishes., R.V. Žikić, A. Š. Štajn, S. Z. Pavlović, B. I. Ognjanović, Z. S. Saičić., and Obsahuje bibliografii
The acanthocephalan parasite Pomphorhynchus laevis (Müller, 1776) uses freshwater amphipods as its intermediate host. In order to complete the life cycle, the infected amphipod must be consumed by a fish, where the acanthocephalan will mature and reproduce. Parasite transmission, and therefore fitness, could be enhanced if infected amphipods fail to detect or avoid predatory fish. We compared the activity levels of infected and non-infected amphipods, Echinogammarus stammeri (Karaman, 1931), in both the presence and absence of odours from its natural, definitive host, the fish Leuciscus cephalus (L.). Throughout the experiment, infected amphipods were more active than were non-infected individuals. The non-infected amphipods reduced their activity after the addition of fish odours, but the infected amphipods failed to show a significant decrease. The failure of infected amphipods to reduce activity levels in the presence of fish odour may reflect a parasite strategy to increase its chances of transmission by making its amphipod host more vulnerable to predation by fish.
The pattern of activity of 1-aminocyclopropane carboxylic acid synthase (ACS) was similar to photosynthetic and growth traits observed at 30, 45, and 60 d after sowing in mustard (Brassica juncea L.) cultivars Varuna and RH 30 differing in photosynthetic capacity. Higher activity of ACS and therefore ethylene release in Varuna than RH 30 increased stomatal conductance, intercellular CO2 concentration, carboxylation rate (carbonic anhydrase and intrinsic water use efficiency), and thus net photosynthetic rate (PN) and leaf and plant dry masses (DM) at all sampling times. Moreover, Varuna also had larger leaf area which contributed to higher PN and DM. A positive correlation between ACS activity and PN and leaf area was found in both the cultivars. Thus ACS activity may affect PN through ethylene-induced changes on foliar gas exchange and leaf growth.
The activity of enzymes characteristic for C4-type photosynthesis was determined in different organs of two herbaceous plants: Reynoutria japonica Houtt. and Helianthus tuberosus L. The activity of phosphoenolpyruvate carboxylase (PEPC) was usually higher in the roots, some of the stem tissues and petioles in comparison to the leaf blades. The highest activity of malic enzymes (NAD-ME, NADP-ME) and phosphoenolpyruvate carboxykinase (PEPCK) was in the petioles and stem tissues of both plants and the lowest in the leaf blades and the pith of Helianthus tuberosus L. and M. Kocurek, J. Pilarski.
Paraoxonase 1 (PON1) seems to have a relevant role in detoxifying processes and in atherosclerosis. The aim of this study was to determine PON1 activity, the total antioxidant capacity, as well as entire lipid profile in children for screening of possible risk of atherosclerosis development. Serum PON1 arylesterase/paraoxonase activities were determined spectrophotometrically. The total antioxidant capacity of the serum was measured by TEAC method. Parameters of lipid profile were analyzed by routine laboratory methods. It has been shown that PON1 arylesterase/ paraoxonase activities were very similar to values found in adults. In children, no significant correlation between PON1 arylesterase activity and HDL was observed. PON1 paraoxonase activity correlated only with atherogenic index. PON1 arylesterase activity was significantly higher in girls than in boys. The antioxidant capacity was inversely related to the body mass index. In this study, PON1 activity was determined in healthy children aged 11 to 12 years and we found a similarity in PON1 activities of children and adults. Moreover, the results of our study support the hypothesis that higher body weight of children may contribute to a greater risk for development of atherosclerosis in which oxidative stress plays a role., K. Sumegová, Z. Nagyová, I. Waczulíková, I. Žitňanová, Z. Ďuračková., and Obsahuje bibliografii a bibliografické odkazy
The impact of heat shock on minimising the activity of photosystem 2 (PS2) initiating high lipid peroxidation (POL) level and consequently changes in the enzymatic-antioxidant protective system was studied in seedlings of two Egyptian cultivars of barley (Giza 124 and 125). Heat doses (35 and 45 °C for 2, 4, 6, and 8 h) decreased chlorophyll (Chl) contents coupled with an increase in Chl a/b ratio, diminished Hill reaction activity, and quenched Chl a fluorescence emission spectra. These parameters reflect the disturbance of the structure, composition, and function of the photosynthetic apparatus as well as the activity of PS2. POL level, as dependent on the balance between pro- and anti-oxidant systems, was directly correlated with temperature, exposure time, and their interaction. Heat shock caused an increase in the electric conductivity of cell membrane, and malonyldialdehyde content (a peroxidation product) coupled with the disappearance of the polyunsaturated linolenic acid (C18:3), reflecting the peroxidation of membrane lipids which led to the loss of membrane selective permeability. Moreover, it induced distinct and significant changes in activities of antioxidant enzymes. Superoxide dismutase and peroxidase activities have been progressively enhanced by moderate and elevated heat doses, but the most elevated one (45 °C for 8 h) showed a decrease in activities of both enzymes. In contrast, catalase activity was reduced with all heat shocks. and F. El-Shintinawy ... [et al.].
We studied the temporal relationships and the patterns of electromyographic activities of the posterior cricoarytenoid and thyreoarytenoid muscles (laryngeal abductor and adductor), the diaphragm and abdominal muscles in anesthetized cats during mechanically induced tracheobronchial and laryngopharyngeal coughs, expiration and aspiration reflexes. The posterior cricoarytenoid muscle activity reached the maxima just before the peak of diaphragmatic activity in both types of cough and aspiration reflexes and slightly before the top of abdominal muscle activity in coughs and the expiration reflex. Thus, this muscle contributes to the inspiratory phase of coughs and aspiration reflex and also to the expulsive phase of coughs and the expiration reflex. The thyreoarytenoid muscle presented strong discharges in the compressive phase of coughs and expiration reflex (during the rising part of the abdominal muscle activity) and in the subsequent laryngoconstriction (following the diaphragmal and/or abdominal muscle activity) in all four reflexes. This muscle was also slightly activated at the beginning of the aspiration reflex. The existence of four phases of the cough reflex is also discussed., I. Poliaček, A. Stránsky, J. Jakuš, H. Baráni, Z. Tomori, E. Halašová., and Obsahuje bibliografii
Results of radar observatlons of tho Orionid and Eta Aquarid meteor showers carried out In Budrio (Italy) wlthin the IHW program are compared with the simultaneous data from Ondřejov
(Czechoslovakia). The activlty of these showers Is studied in the relation to the motion of large particles ejected from the comet. The activity was found to be independent on tho approach of the parent comet.