Comparison of blood pro/antioxidant levels before and after acute exercise in athletes and non-athletes

The aims of our study were to assess the redox state of adolescent athletes and non-athletes both at rest and after acute exposure to physical load and to find relations between parameters of redox state and morphofunctional characteristics of subjects. 58 young handball players and 37 non-athletes were subjected to body composition analysis, measuring of maximal oxygen consumption and blood sampling immediately before and after a maximal progressive exercise test. At rest, athletes had significantly higher superoxide dismutase (SOD) and catalase (CAT) activity, higher levels of glutathione (GSH) and nitric oxide (NO) and lower levels of lipid peroxidation (TBARS) compared with non-athletes. A maximal exercise test induced statistically significant rise of superoxide anion radical (O2-), hydrogen peroxide (H2O2) and NO levels in non-athletes, while TBARS levels decreased. Athletes experienced the fall in NO levels and the fall in CAT activity. After exercise, athletes had significantly lower levels of O2- compared with non-athletes. Two way repeated measures ANOVA showed that the response of O2-, NO and TBARS to the exercise test was dependent on the sports engagement (training experience) of subjects. Significant correlations between morphofunctional and redox parameters were found. These results suggest that physical fitness affects redox homeostasis.     

Comparison of short-term and medium-term swimming training on cardiodynamics and coronary flow in high salt-induced hypertensive and normotensive rats

Dbl-family guanine nucleotide exchange factors (GEFs) can activate RhoGTPases by facilitating the exchange of GDP for GTP, the aberrant expression of which has been implicated in tumorigenicity and metastasis of human cancers. ARHGEF39, as a member of Dbl-family GEFs, was reported to be a potential oncogene in human hepatocellular carcinoma previously. However, the role of ARHGEF39 in gastric cancer (GC) remains unclear so far. In the current study, we demonstrated that ARHGEF39 expression was significantly upregulated in GC tissues compared with paired adjacent normal tissues by quantitative real-time PCR analysis. Functional analyses revealed that ARHGEF39 overexpression could promote proliferation, colony formation, and migration of GC cells in vitro, whereas ARHGEF39 knockdown markedly suppressed these phenotypes. Moreover, ARHGEF39 enhanced tumorigenicity and lung metastasis potential of GC cells in nude mice model. Mechanistically, we found that overexpressed ARHGEF39 significantly increased the phosphorylation level of Akt (p-Akt), and its effect on cell proliferation was attenuated by PI3K inhibitor LY294002. Thus, our findings suggest that ARHGEF39 may contribute to cell proliferation and migration in GC via a possible mechanism involving Akt signaling.     

Exercise-induced changes in redox status of elite karate athletes

Regular training has been claimed to increase the activity of antioxidant enzymes and, consequently, augments the resistance to oxidative stress; however, large volumes of training performed by elite sportsmen could lead to a chronic oxidative stress state. The aim of our study was to assess the oxidative status of elite athletes at the beginning of the preparatory and the beginning of the competition training phases, so that the influence of three months of programmed physical activity on redox status could be determined. The chronic effects of exercise on the redox state of the athletes were compared to the effects of a single bout of karate training. Thirty elite karate athletes, 16-30 years old, were subjected to maximal graded exercise test to estimate their aerobic capacity; blood sampling was also performed to measure levels of superoxide anion radical (O??), hydrogen peroxide (H?O?), superoxide dismutase activity (SOD) and catalase activity (CAT). The only significant change after the three-month training process was found in the significantly decreased CAT activity (X ± SE: 7.95 ± 0.13 U/g Hb × 103 in the preparatory period, 6.65 ± 0.28 U/g Hb × 103 in the competition stage; P < 0.01). After a single karate training session, there was statistically significant decrease of O??(X ± SE: 32.7 ± 4.9 nmol/ml in the preparatory period, 24.5 ± 2.5 nmol/ml in the competition stage; P < 0.05) and increase of H?O?(X ± SE: 11.8 ± 1.0 nmol/ml in the preparatory period, 14.2 ± 0.9 nmol/ml in the competition stage; P < 0.01), as well as significant CAT increase (X ± SE: 6.6 ± 0.6 U/g Hb × 103 in the preparatory period, 8.5 ± 0.5 U/g Hb × 103 in the competition stage; P < 0.05). Although the three-month training process induced, at the first sight, negative changes in the redox state, expressed through the decrease in CAT activity, adequate response of the antioxidant system of our athletes to acute exercise was preserved.     

Manipulation of cytokinesis affects polar ionic current around the egg of Lymnaea stagnalis

Summary The fertilized egg of the mollusc Lymnaea stagnalis generates a polarized current pattern as measured with the vibrating probe. Here we investigated the basis of these polar ionic currents. Ionic currents were measured around eggs during the second meiotic division after interference with cytokinesis. Cytokinesis was either displaced by centrifugation or inhibited with cytochalasin or nocodazole. Furthermore, ectopic constrictions were induced with lectin treatment. It appeared that the inward current of the animal pole can be displaced by centrifugation and remains associated with the position of the meiotic apparatus. The influence of the meiotic apparatus on the polar current pattern seems to be directly related to membrane constrictions rather than to karyokinesis. This was demonstrated by a change in current density after induction of an ectopic constriction at the vegetal pole and by the abolishment of currents after cytochalasin treatment. Since the location of the outward current was not sensitive to centrifugation, it may be concluded that the vegetal outward current depends upon properties of the vegetal cortex. On the basis of these results, we conclude that the Lymnaea egg generates two types of ionic currents during the second meiotic division. The first is an inward current activated at the site of membrane constrictions. The second is an outward current associated with the vegetal cortex.     

Ocular clocks are tightly coupled and act as pacemakers in the circadian system of Japanese quail

Our previous studies showed that the eyes of Japanese quail contain a biological clock that drives a daily rhythm of melatonin synthesis. Furthermore, we hypothesized that these ocular clocks are pacemakers because eye removal abolishes freerunning rhythms in constant darkness (DD). If the eyes are indeed acting as pacemakers, we predicted that the two ocular pacemakers in an individual bird must remain in phase in DD and, furthermore, the two ocular pacemakers would rapidly regain coupling after being forced out of phase. These predictions were confirmed by demonstrating that 1) the ocular melatonin rhythms of the two eyes maintained phase for at least 57 days in DD and 2) after ocular pacemakers were forced out of phase by alternately patching the eyes in constant light, two components of body temperature were observed that fused into a consolidated rhythm after 5-6 days in DD, showing pacemaker recoupling. The ability to maintain phase in DD and rapidly recouple after out-of-phase entrainment demonstrates that the eyes are strongly coupled pacemakers that work in synchrony to drive circadian rhythmicity in Japanese quail.     

Oxidative stress and nitrite dynamics under maximal load in elite athletes: relation to sport type

Maximal workload in elite athletes induces increased generation of reactive oxygen/nitrogen species (RONS) and oxidative stress, but the dynamics of RONS production are not fully explored. The aim of our study was to examine the effects of long-term engagement in sports with different energy requirements (aerobic, anaerobic, and aerobic/anaerobic) on oxidative stress parameters during progressive exercise test. Concentrations of lactates, nitric oxide (NO) measured through stabile end product-nitrites (NO₂ ^?), superoxide anion radical (O₂ ^??), and thiobarbituric reactive substances (TBARS) as index of lipid peroxidation were determined in rest, after maximal workload, and at 4 and 10th min of recovery in blood plasma of top level competitors in rowing, cycling, and taekwondo. Results showed that sportmen had similar concentrations of lactates and O₂ ^?? in rest. Nitrite concentrations in rest were the lowest in taekwondo fighters, while rowers had the highest levels among examined groups. The order of magnitude for TBARS level in the rest was bicycling > taekwondo > rowing. During exercise at maximal intensity, the concentration of lactate significantly elevated to similar levels in all tested sportsmen and they were persistently elevated during recovery period of 4 and 10 min. There were no significant changes in O₂ ^??, nitrite, and TBARS levels neither at the maximum intensity of exercise nor during the recovery period comparing to the rest period in examined individuals. Our results showed that long term different training strategies establish different basal nitrites and lipid peroxidation levels in sportmen. However, progressive exercise does not influence basal nitrite and oxidative stress parameters level neither at maximal load nor during the first 10 min of recovery in sportmen studied.     

Exopolysaccharide Production and Ropy Phenotype Are Determined by Two Gene Clusters in Putative Probiotic Strain Lactobacillus paraplantarum BGCG11

Lactobacillus paraplantarum BGCG11, a putative probiotic strain isolated from a soft, white, artisanal cheese, produces a high-molecular-weight heteropolysaccharide, exopolysaccharide (EPS)-CG11, responsible for the ropy phenotype and immunomodulatory activity of the strain. In this study, a 26.4-kb region originating from the pCG1 plasmid, previously shown to be responsible for the production of EPS-CG11 and a ropy phenotype, was cloned, sequenced, and functionally characterized. In this region 16 putative open reading frames (ORFs), encoding enzymes for the production of EPS-CG11, were organized in specific loci involved in the biosynthesis of the repeat unit, polymerization, export, regulation, and chain length determination. Interestingly, downstream of the eps gene cluster, a putative transposase gene was identified, followed by an additional rfb gene cluster containing the rfbACBD genes, the ones most probably responsible for dTDP-l-rhamnose biosynthesis. The functional analysis showed that the production of the high-molecular-weight fraction of EPS-CG11 was absent in two knockout mutants, one in the eps and the other in the rfb gene cluster, as confirmed by size exclusion chromatography analysis. Therefore, both eps and rfb genes clusters are prerequisites for the production of high-molecular-weight EPS-CG11 and for the ropy phenotype of strain L. paraplantarum BGCG11.     

Two-way avoidance and acute shock stress induced alterations of regional noradrenergic, dopaminergic and serotonergic activity in Roman high- and low-avoidance rats

Various brain regions of male RHA/Verh and RLA/Verh rats were dissected out and deep-frozen immediately after 30 min in a shuttle box involving a) no shock (control), b) 40 inescapable shocks or c) 40 avoidable shocks. The RHA/Verh rats used in the "c" category exhibited about 80-85% learned avoidance. 5-HT, 5-HIAA, NA, MHPG-SO4, DA, DOPAC and HVA levels were subsequently measured in selected regions. NA levels were considerably reduced in the hypothalamus and pons/medulla of both selected lines of rats after acute shock stress, supporting the results of numerous studies which have indicated that NA turnover is nonspecifically increased by all types of stress, at least in those regions. An increase in cortical MHPG-SO4 and a reduction in hypothalamic 5-HT seen after avoidance learning also occurred after shock stress in RHA/Verh rats. Whereas RLA/Verh rats showed an increased metabolism of 5-HT in the hypothalamus and pons/medulla after shock stress, RHA/Verh rats showed the opposite response in the hypothalamus after the same treatment. A reduction in 5-HT metabolism was also evident in RHA/Verh rats, after avoidance learning, in the cortex, hippocampus and hypothalamus. These results indicated, pending further studies regarding, for example, possible genetic differences in tryptophan uptake and utilization, that 5-HT probably plays at least a modulatory role in the reaction to stress, and in avoidance behavior. That role may be either active or passive, depending upon the emotional status of the subjects. In regard to the DA responses measured in striatum and hypothalamus of the two rat lines, some divergent inter-treatment tendencies, as well as some similarities, were seen in DA metabolism in both regions, but almost none of the differences were significant.