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1.
Extremophiles ; 18(6): 1075-84, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25116056

ABSTRACT

The occurrence and importance of photoautotrophic picoplankton (PPP, cells with a diameter <2 µm) was studied along a trophic and salinity gradient in hypersaline lakes of the Transylvanian Basin (Romania). The studied lakes were found to be rich in PPP, with abundances (maximum 7.6 × 10(6) cells mL(-1)) higher than in freshwater and marine environments of similar trophic conditions. The contribution of PPP to the total phytoplankton biovolume did not decrease with increasing trophic state as it was generally found in other aquatic environments. Regardless of the trophic conditions, the contribution of PPP could reach 90-100 % in these hypersaline lakes. We hypothesized that the PPP predominance might be the result of the low grazing pressure, since heterotrophic nanoflagellates (the main grazers of PPP) were absent in the studied samples. There were significant differences in community composition among the lakes along the salinity gradient. CyPPP predominated in less saline waters (mainly below 5 %), while EuPPP were present along the entire salinity range (up to 18.7 %), dominating the phytoplankton between 3 and 13 % salinity. Above 13 % salinity, the phytoplankton was composed mainly of Dunaliella species.


Subject(s)
Biodiversity , Lakes/chemistry , Phytoplankton/isolation & purification , Sodium Chloride/analysis , Chlorophyll/analysis , Cyanobacteria/isolation & purification , Lakes/microbiology , Phytoplankton/classification
2.
Food Chem Toxicol ; 61: 36-41, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23419390

ABSTRACT

The effects of treadmill running (8 weeks, 5 times/week, 1h/day at 27 m/min), caloric restriction, and cocoa supplementation on brain function and oxidative stress markers were tested. The Morris maze test was used to appraise rat memory. Regular exercise significantly improved spatial learning performance. The level of oxidative stress was measured by the concentration of carbonylated proteins. The free radical concentration increased in brain of the training groups but not the controls. The content of reactive carbonyl derivates did not change with exercise, suggesting that the increased production of reactive oxygen species (ROS) were well tolerated in this experimental model. Caloric restriction (CR) decreased the accumulation of free radicals in the frontal lobe. The protein content of brain-derived neutrophic factors (BDNFs) was evaluated and changes did not occur either with exercise or cocoa supplementation treatments. These data did not show significant effects of the administration of cocoa (2% w/w) on the concentration of ROS, BDNF or on spatial memory. Conversely, exercise and CR can play a role in ROS generation and brain function.


Subject(s)
Brain/drug effects , Brain/metabolism , Cacao , Caloric Restriction , Dietary Supplements , Memory/drug effects , Oxidative Stress/drug effects , Animals , Biomarkers/metabolism , Brain-Derived Neurotrophic Factor/metabolism , Cacao/chemistry , Free Radicals/metabolism , Male , Maze Learning/drug effects , Memory/physiology , Physical Exertion , Protein Carbonylation/drug effects , Rats , Rats, Wistar , Reactive Oxygen Species/metabolism
3.
Extremophiles ; 16(5): 759-69, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22878729

ABSTRACT

Our survey has revealed that the phytoplankton in the anthropo-hypersaline lakes of the Transylvanian Basin (Romania) was often dominated by photoautotrophic picoplankton (PPP, cells with a diameter <2 µm). Therefore, the aim of this study was to identify PPP members both in the summer and the winter communities using molecular biological techniques, denaturing gradient gel electrophoresis (DGGE) and sequence analysis. The applied PCR-DGGE methods were highly specific to cyanobacteria and green algae. A total of 11 different plankton taxa were identified that were related to several distant taxonomic groups. PPP were represented by a simple community and consisted of two major genotypes, one from the green algal species Picochlorum oklahomense and the other related to marine Synechococcus isolates (Cyanobacteria). These marine PPP species were recorded for the first time in inland saline lakes from Europe. Besides picoplankton, several additional marine taxa (e.g. cryptophytes and haptophytes) were detected among the nanoplankton species. The presence of the identified marine and hypersaline species could be explained by wind, precipitation or waterfowl transfer; however, this latter could have smaller importance.


Subject(s)
Biodiversity , Lakes/microbiology , Phytoplankton/physiology , Water Microbiology , Chlorophyta/physiology , Romania , Synechococcus/physiology
4.
J Strength Cond Res ; 23(1): 121-6, 2009 Jan.
Article in English | MEDLINE | ID: mdl-19125100

ABSTRACT

The aim of our research was primarily to compare the conditional abilities of European countries' Fédération Internationale de Football Association (FIFA) referees with those of Hungarian national and county referees and, secondly, to investigate whether the stop tests of FIFA and the Union of European Football Associations (UEFA) provide reliable discrimination criteria between the different levels of referees. The main focuses of our research were speed and endurance, which were measured by the stop tests of FIFA and UEFA-namely, 50- and 200-m sprint runs and a 12-minute run, respectively (Cooper test). In our study, the test results of 2459 soccer referees were analyzed; they include the results of the total Hungarian population of referees and the results from 17 different European countries. Referees were classified into 6 different levels according to their qualifications. The results show that in the 12-minute run, FIFA referees covered the longest distance (3043 +/- 127 m), followed by the Hungarian elite referees (2939 +/- 136 m); less distance was covered by county III-level referees (2522 +/- 270 m). Differences between groups in the endurance event were significant (p < 0.05) in all cases. In the sprint runs, there was no difference between FIFA and Hungarian elite referees. In both sprints, FIFA-level and Hungarian elite referees performed the fastest times, and county III-level referees had the slowest times. It can be concluded that the aerobic fitness level demonstrated in the 12-minute run provides the most adequate criteria for discrimination between different competitive levels. Hungarian elite referees, on the basis of their fitness test results, are comparable with international-level referees. The major quality step in a referee's career can be located at the third-division competition level.


Subject(s)
Exercise Test/methods , Physical Exertion , Physical Fitness/physiology , Soccer/physiology , Adult , Analysis of Variance , Environmental Monitoring/statistics & numerical data , Europe , Humans , Hungary , International Cooperation , Job Description , Male , Observer Variation , Occupational Exposure/statistics & numerical data , Physical Endurance , Probability , Task Performance and Analysis
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