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21.
Kubová Z Kremlácek J Szanyi J Chlubnová J Kuba M 《Physiological research / Academia Scientiarum Bohemoslovaca》2002,51(2):199-204
Visual cognitive responses (P300) to moving stimuli were tested in 36 subjects with the aim to find the normal range of P300 parameters. Concomitantly, the circadian intra-individual variability of the P300 was studied in a subgroup of 6 subjects. Visual stimuli consisted of either coherent (frequent stimulus) or non-coherent motion (random stimulus). The oddball paradigm was applied for recording cognitive responses. P300 to rare stimuli had an average latency of 447.3 +/- 46.6 ms and amplitude of 12.9 +/- 6.0 microV. The average reaction time was in the range from 322 to 611 ms and there was no correlation between the reaction time and P300 latency. We did not find any significant circadian changes of the P300 parameters in the 6 subjects tested four times during the same day. Cognitive (event-related) responses (P300) displayed distinctly greater inter-individual variability (S.D. of 50 ms) when compared with pattern-reversal and motion-onset VEPs (S.D. of 6.0 ms and 14 ms, respectively). For this reason, the clinical use of P300 elicited by this kind of visual stimuli seems to be rather restricted and the evaluation of its intra-individual changes is preferable. 相似文献
22.
Da Silva-Grigoletto ME Fernández JM de Sá CA Gómez-Puerto JR Vaamonde D Pérez-Jiménez F 《Journal of strength and conditioning research / National Strength & Conditioning Association》2010,24(12):3334-3342
The addition of fructose (F) to a glucose (G) supplement may modify the metabolic response during exercise; however, its effect on perceived exertion (PE) and its influence on postprandial metabolism have not been jointly studied in different types of exercise. This study sought to assess the acute effects of F addition to a G supplement on PE and on the postprandial metabolic response during a single bout of either strength exercise (SE) or endurance exercise (EE). Twenty physically trained men ingested an oral dose of G or GF 15 minutes before starting a 30-minute session of SE (10 sets of 10 repetitions of half squat) or EE (cycling). The combination resulted in 4 randomized interventions in a crossover design in which all subjects performed all experimental conditions: G + SE, GF + SE, G + EE, and GF + SE. Perceived exertion, heart rate (HR), G, insulin, lactate, and urinary catecholamine levels were measured before exercise, during the exercise, and during acute recovery. Perceived exertion during exercise was lower for GF than for G during SE and EE (mean ± SD; 8.95 ± 0.62 vs. 9.26 ± 0.65, p < 0.05 and 7.47 ± 0.84 vs. 7.74 ± 0.93, p < 0.05, respectively). The glycemic peak in GF + SE was lower than in G + SE (p < 0.05), and there was a second peak during recovery (p < 0.05), whereas in EE, no difference in blood G levels was noted between G and GF supplements. Moreover, HR, urinary adrenalin, and noradrenalin were lower in GF than in G (p < 0.05), though only for EE. The results showed that PE is positively affected by GF supplementation for both SE and EE and thus may be a useful dietary strategy for helping to achieve higher training loads. 相似文献
23.
AIMS: To examine the potential of Zymomonas mobilis entrapped into polyvinylalcohol (PVA) lens-shaped immobilizates in batch and continuous ethanol production. METHODS AND RESULTS: Cells, free or immobilized in PVA hydrogel-based lens-shaped immobilizates - LentiKats, were cultivated on glucose medium in a 1 l bioreactor. In comparison with free cell cultivation, volumetric productivity of immobilized batch culture was nine times higher (43.6 g l(-1) h(-1)). The continuously operated system did not improve the efficiency (volumetric productivity of the immobilized cells 30.7 g l(-1) h(-1)). CONCLUSIONS: We demonstrated Z. mobilis capability, entrapped into LentiKats, in the cost-efficient batch system of ethanol production. SIGNIFICANCE AND IMPACT OF THE STUDY: The results reported here emphasize the potential of bacteria in combination with suitable fermentation technology in industrial scale. The innovation compared with traditional systems is characterized by excellent long-term stability, high volumetric productivity and other technological advantages. 相似文献
24.
Kváč M Kestřánová M Květoňová D Kotková M Ortega Y McEvoy J Sak B 《Experimental parasitology》2012,131(1):107-110
Three and 8 week old pigs were inoculated with Cryptosporidium muris HZ206 (Mus musculus musculus isolate), Cryptosporidium tyzerri CR2090 (M. m. musculus isolate) or C. tyzzeri CR4293 (isolate from a hybrid between Mus musculus domesticus and M. m. musculus) at a dose of 1 × 10(7) oocysts per animal. Inoculated pigs showed no detectable infection and no clinical symptoms of cryptosporidiosis during 30 days post infection (DPI), and no macroscopic changes were detected in the digestive tract following necropsy. Developmental stages were not detected in gastrointestinal tract tissue by histology or PCR throughout the duration of the experiment. The infectivity of isolates was verified on SCID mice, in which oocysts shedding started from 4 to 8 DPI. Based on our findings, it can be concluded that pigs are not susceptible to C. muris or C. tyzzeri infection. 相似文献
25.
A family of gamma-like calcium channel subunits 总被引:8,自引:0,他引:8
The gamma subunit was initially identified as an auxiliary subunit of the skeletal muscle calcium channel complex. Evidence for the existence of further gamma subunits arose following the characterization of a genetic defect that induces epileptic seizures in stargazer mice. We present here the first account of a family of at least five putative gamma subunits that are predominantly expressed in brain. The gamma-2 and gamma-4 subunits shift the steady-state inactivation curve to more hyperpolarized potentials upon coexpression with the P/Q type alpha(1A) subunit. The coexpression of the gamma-5 subunit accelerates the time course of current activation and inactivation of the alpha(1G) T-type calcium channel. 相似文献
26.
The fluid mosaic model of membrane structure has been revised in recent years as it has become evident that domains of different lipid composition are present in eukaryotic and prokaryotic cells. Using membrane binding fluorescent dyes, we demonstrate the presence of lipid spirals extending along the long axis of cells of the rod-shaped bacterium Bacillus subtilis. These spiral structures are absent from cells in which the synthesis of phosphatidylglycerol is disrupted, suggesting an enrichment in anionic phospholipids. Green fluorescent protein fusions of the cell division protein MinD also form spiral structures and these were shown by fluorescence resonance energy transfer to be coincident with the lipid spirals. These data indicate a higher level of membrane lipid organization than previously observed and a primary role for lipid spirals in determining the site of cell division in bacterial cells. 相似文献
27.
Sulfotransferases and sulfatases are the major enzymes responsible for sulfate transfer processes. The past two years have seen the elucidation of new functions for these enzymes, and a great progression in their structural characterization, which confirms that these two types of enzymes possess a highly conserved fold. For catalytic activity, sulfatases must contain a formylglycine residue, which is generated by various formylglycine-generating enzymes. Mechanistic and structural details have recently been obtained for a group of cofactor-independent formylglycine-generating enzymes termed FGEs. Finally, an increasing light has been cast upon the mechanism of sulfatase inactivation by a group of clinically important agents, the aryl sulfamates. 相似文献
28.
Deletion of PsbM in tobacco alters the QB site properties and the electron flow within photosystem II 总被引:1,自引:0,他引:1
Umate P Schwenkert S Karbat I Dal Bosco C Mlcòchová L Volz S Zer H Herrmann RG Ohad I Meurer J 《The Journal of biological chemistry》2007,282(13):9758-9767
Photosystem II, the oxygen-evolving complex of photosynthetic organisms, includes an intriguingly large number of low molecular weight polypeptides, including PsbM. Here we describe the first knock-out of psbM using a transplastomic, reverse genetics approach in a higher plant. Homoplastomic Delta psbM plants exhibit photoautotrophic growth. Biochemical, biophysical, and immunological analyses demonstrate that PsbM is not required for biogenesis of higher order photosystem II complexes. However, photosystem II is highly light-sensitive, and its activity is significantly decreased in Delta psbM, whereas kinetics of plastid protein synthesis, reassembly of photosystem II, and recovery of its activity are comparable with the wild type. Unlike wild type, phosphorylation of the reaction center proteins D1 and D2 is severely reduced, whereas the redox-controlled phosphorylation of photosystem II light-harvesting complex is reversely regulated in Delta psbM plants because of accumulation of reduced plastoquinone in the dark and a limited photosystem II-mediated electron transport in the light. Charge recombination in Delta psbM measured by thermoluminescence oscillations significantly differs from the 2/6 patterns in the wild type. A simulation program of thermoluminescence oscillations indicates a higher Q(B)/Q(-)(B) ratio in dark-adapted mutant thylakoids relative to the wild type. The interaction of the Q(A)/Q(B) sites estimated by shifts in the maximal thermoluminescence emission temperature of the Q band, induced by binding of different herbicides to the Q(B) site, is changed indicating alteration of the activation energy for back electron flow. We conclude that PsbM is primarily involved in the interaction of the redox components important for the electron flow within, outward, and backward to photosystem II. 相似文献
29.
Amit?Savaya-Alkalay Ofer?Ovadia Assaf?Barki Amir?SagiEmail author 《Biological invasions》2018,20(1):137-149
All-male populations of the freshwater prawn Macrobrachium rosenbergii were recently produced by a novel temporal RNA interference (RNAi)-based biotechnology for aquaculture purposes. This biotechnology opens the way to the wide use of all-male prawn populations as sustainable biocontrol agents against invading populations of freshwater snails, for which there is currently no environmentally friendly solution. Among the most damaging of the invasive freshwater snail species are the apple snails (Pomacea spp.), which inflict major damage on natural ecosystems and rice fields. The proposed use of all-male prawn populations as environmentally friendly biocontrol agents against invasive freshwater snails has several advantages: efficient predation by the prawns over a wide range of freshwater snails, the ready availability of the prawns, and the monosex non-reproductive nature of the biocontrol agents. Since the aquatic predators are strongly size selective, we quantified the predation rate as a function of body size of both predator and prey (M. rosenbergii and P. caniculata). Medium-sized and large prawns (~10–30 g) efficiently preyed small and medium-sized snails (up to 15 mm), while small prawns (up to 4 g) immediately and completely eradicated snail hatchlings. Medium-sized prawns (~22 g) exterminated a significant fraction of snail biomass within 24 h (up to 58% of their body mass) after being introduced into a tank of snails. A typical ‘climbing-to-the surface’ anti-predator behavior of the snails was recorded. The potential of all-male prawns as efficient biocontrol agents over hatchling and adult apple snails as part of an integrated pest management program is discussed. Our experiments set the stage for evaluating the ecological and economic implications of this generic solution for a wide variety of habitats. 相似文献
30.
The effect of gamma-radiation (3Gy) on slowly proliferating liver tissue of male rats and their progeny was investigated with respect to induction and duration of latent damage. The irradiation caused latent cytogenetic damage in the liver in irradiated males of the F(0) generation, which manifested itself in different ways during proliferation of hepatocytes induced by partial hepatectomy: a reduced proliferating activity, a higher frequency of chromosomal aberrations and a higher proportion of cells with apoptotic DNA fragments were observed, compared with non-irradiated rats. In the progeny of irradiated males (F(1) and F(2) generation), the latent genome damage manifested itself during regeneration of the liver after partial hepatectomy by similar, but less pronounced changes compared with those seen in irradiated males of the parental generation. This finding gave evidence of the transfer of part of the radiation-induced genome damage from parents to their offspring. Irradiation of F(1) and F(2) progeny of irradiated males (their total radiation load being 3 + 3 and 3 + 0 + 3 Gy, respectively) caused less change as irradiation of progeny of non-irradiated control males (their total radiation load being 0 + 3 and 0 + 0 + 3 Gy, respectively). 相似文献