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981.
We have investigated the local and regional scale genetic structure of Siberian primrose (Primula nutans) populations in Northern Europe. The genetic diversity and structure of fifteen populations sampled from the Bothnian Bay
in Finland, the Barents Sea in Norway and the White Sea in Russia were assessed using eleven microsatellite markers. We investigated
the distribution of genetic variation within and between populations, and studied the local genetic structure using spatial
autocorrelation analysis. We found very low genetic and allelic diversity in the Bothnian Bay and Barents Sea populations,
and only slightly higher in the White Sea population. The level of genetic differentiation between the regions was very high,
whereas differentiation between the populations within the regions was moderate. We found no spatial structuring of populations
in any region suggesting efficient dispersal on a local scale. Clonal reproduction seemed to have no effect on genetic structure. 相似文献
982.
Nino Asatiani Tamar Kartvelishvili Marina Abuladze Lali Asanishvili Nelly Sapojnikova 《Biological trace element research》2011,142(3):388-397
The changes in glutathione-dependent cycle enzymes and catalase activities under Cr(VI)-induced oxidative stress were investigated
in two distinct cell lines: L-41−human epithelial-like cells and HLF−fetal human diploid lung fibroblasts, which differ in
tissue origin, proliferation, and antioxidant enzymes activities. The chromium concentrations from 1 to 5 μM cause nontoxic
effects and activate antioxidant enzymes to overcome oxidative stress. In spite of some differences in the endogenous antioxidant
activities, both cell lines reveal the same range of toxic concentrations (20–30 μM). The irreversible inhibition of glutathione-dependent
antioxidant enzymes develops under toxic concentrations and serves as a marker of toxicity. The endogenous antioxidant activity
influences time-dependent expression of Cr(VI) toxicity and the dynamics of antioxidant enzymes activity under nontoxic conditions.
The cell antioxidant defense system is an important marker of the cell adaptive capacity under nontoxic and toxic conditions. 相似文献
983.
Park SJ Park BJ Jung MY Kim SJ Chae JC Roh Y Forwick M Yoon HI Rhee SK 《Microbial ecology》2011,62(3):537-548
Increases in global temperatures have been shown to enhance glacier melting in the Arctic region. Here, we have evaluated
the effects of meltwater runoff on the microbial communities of coastal marine sediment located along a transect of Temelfjorden,
in Svalbard. As close to the glacier front, the sediment properties were clearly influenced by deglaciation. Denaturing gradient
gel electrophoresis profiles showed that the sediment microbial communities of the stations of glacier front (stations 188–178)
were distinguishable from that of outer fjord region (station 176). Canonical correspondence analysis indicated that total
carbon and calcium carbonate in sediment and chlorophyll a in bottom water were key factors driving the change of microbial
communities. Analysis of 16S rRNA gene clone libraries suggested that microbial diversity was higher within the glacier–proximal
zone (station 188) directly affected by the runoffs than in the outer fjord region. While the crenarchaeotal group I.1a dominated
at station 176 (62%), Marine Benthic Group-B and other Crenarchaeota groups were proportionally abundant. With regard to the
bacterial community, alpha-Proteobacteria and Flavobacteria lineages prevailed (60%) at station 188, whereas delta-Proteobacteria (largely sulfate-reducers) predominated (32%) at station 176. Considering no clone sequences related to sulfate-reducers,
station 188 may be more oxic compared to station 176. The distance-wise compositional variation in the microbial communities
is attributable to their adaptations to the sediment environments which are differentially affected by melting glaciers. 相似文献
984.
985.
Guillaume Gayet Cyril Eraud Maurice Benmergui Joël Broyer François Mesleard Hervé Fritz Matthieu Guillemain 《European Journal of Wildlife Research》2011,57(5):1051-1056
A number of native and exotic animal species show dramatic population increases in terms of both numbers and geographic range.
Understanding the habitat selection processes behind such increases is crucial to implement adequate management measures.
Mute swan (Cygnus olor) populations have experienced a tremendous demographic and geographic expansion in Western Europe during the twentieth century,
colonizing a wide variety of aquatic habitats. We aimed at assessing how swans select nesting sites during the pre-laying
and laying periods on medium to large fishponds (from 10 to 50 ha) in Eastern France, while accounting for detectability biases
and testing for the effects of fishpond spatial configuration, vegetation resources, human disturbance and habitat management.
Our results demonstrate that the mute swan is a non-selective species regarding its nesting habitat among such fishponds,
using these independently from the parameters considered although fishpond characteristics varied. Although mute swan is one
of the least cryptic Anatidae, owing to its white colour and large size, detection of breeding pairs remained imperfect for
each over several sampling occasions. However, because we repeated the sampling sessions, detection of swan pairs by the end
of the monitoring period was as high as 0.94. These results are consistent with previous assertions that the mute swan is
a species of high ecological plasticity, which may partly explain its recent colonization rates. Given that even swan breeding
events were imperfectly detected on each occasion, we highlight the fact that most studies of breeding ducks (which are more
cryptic) would be considerably improved by better considering detection biases. 相似文献
986.
Barton HJ 《Biological trace element research》2011,143(2):637-658
The population of about 300 6-year-old preschool children was studied for lead (Pb) and cadmium (Cd) in deciduous teeth, scalp
hair, and capillary blood. Zinc (Zn) content in hair was also measured due to its possible interferences with the elements
studied. The Pb and Cd contents were measured by graphite furnace atomic absorption spectrometry with Zeeman background correction,
and Zn, by flame method. Metal levels found were comparable to those in European countries. Positive correlations between
Pb and Cd in the same and different tissues were widespread (r = 0.23–0.68). A positive correlation was found between Pb in teeth and blood (r = 0.65, p < 0.001). Pb blood threshold 100 μg L−1 referred to 2.6 μg g−1 Pb in teeth. Predictability of this Pb teeth limit was 14% vs. 5% for Pb blood. Strong negative correlation was found between
hair Pb and Zn (r = −0.68, p < 0.001). Enhanced Cd and Zn levels in hair were associated with the household drinking water hardness. The associations
with some other environmental and behavioral factors were also presented and discussed. The results proved the advantage of
analysis of primary teeth for Pb exposure screening of preschool children. 相似文献
987.
Pavlik R Wypior G Hecht S Papadopoulos P Kupka M Thaler C Wiest I Pestka A Friese K Jeschke U 《Histochemistry and cell biology》2011,136(3):289-299
Estradiol and progesterone mediate their actions by binding to classical nuclear receptors, estrogen receptor α (ERα) and
estrogen receptor β (ERβ) and progesterone receptor A and B (PR-A and PR-B) and the non-classical G protein-coupled estrogen
receptor (GPER). Several animal knock-out models have shown the importance of the receptors for growth of the oocyte and ovulation.
The aim of our study was to identify GPER in human granulosa cells (GC) for the first time. Moreover, the effect of different
doses of gonadotropins on estrogen and progesterone receptors in the human ovary should be investigated as follicle stimulating
hormone (FSH) and luteinizing hormone (LH) are also responsible for numerous mechanisms in the ovary like induction of the
steroid biosynthesis. Human GC were cultured in vitro and stimulated with different doses of recombinant human FSH or LH.
Receptor expression was analyzed by immunocytochemistry and quantitative real-time RT-PCR. GPER could be identified for the
first time in human GC. It could be shown that high concentrations of LH increase GPER protein expression. Furthermore FSH
and LH increased ERβ, PR-A and PR-B significantly on protein level. These findings were verified for high doses of FSH and
LH on mRNA level. ERα was not affected with FSH or LH. We assume that gonadotropins induce GPER, ERβ and PR in luteinized
granulosa cells. 相似文献
988.
Beblo K Douki T Schmalz G Rachel R Wirth R Huber H Reitz G Rettberg P 《Archives of microbiology》2011,193(11):797-809
In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylogenetically deep-branching thermophilic
Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine
out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation
such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions.
If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells
irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before
irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution
of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied
fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyperthermophilic
microorganisms. 相似文献
989.
Sandra G Brauer Marjorie H Woollacott Robyn Lamont Sandy Clewett John O'Sullivan Peter Silburn George D Mellick Meg E Morris 《BMC neurology》2011,11(1):90
Background
Difficulty performing more than one task at a time (dual tasking) is a common and disabling problem experienced by people with Parkinson disease (PD). If asked to perform another task when walking, people with PD often take shorter steps or walk more slowly. Currently there is uncertainty about whether clinicians should teach people with PD to avoid dual tasking or whether they should encourage them to practice dual tasking with the hope that practice will lead to enhanced performance. This study will address this issue by comparing single to dual task gait training. 相似文献990.
Plum is a highly perishable fruit and postharvest fruit softening limits its shelf life. The aim of this work was to study
the specific effects of 1-methylcyclopropene (1-MCP) treatment on physiological changes in ‘Zaohong’ plums. Plums were treated
with 500 nL L−1 1-MCP at 20°C for 18 h followed by 20°C storage. The results showed that 1-MCP treatment significantly reduced endogenous
ethylene production and the activities of ethylene biosynthetic enzymes’ (1-aminocyclopropane-1-carboxylic acid synthase,
ACS and 1-aminocyclopropane-1-carboxylic acid oxidase, ACO) in plum fruit during storage when compared with untreated fruit.
Although 1-MCP treatment inhibited ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) accumulation, it did
not inhibit the accumulation of N-malonyl-ACC (MACC). Higher firmness was also found in 1-MCP-treated plums than in controls. During storage, superoxide anion
(O2−·) and hydrogen peroxide (H2O2) levels decreased in 1-MCP-treated fruit. 1-MCP treatment also regulated superoxide dismutase (SOD) and catalase (CAT) activities
during storage. Xylanase activity was upregulated while activities of polygalacturonase (PG), pectin methyl esterase (PME)
and cellulase enzymes in the fruit were downregulated by 1-MCP treatment. In conclusion, 1-MCP might be a potent compound
for extending both storage period and shelf life of ‘Zaohong’ plums by suppressing ethylene biosynthesis, regulating cell
wall degradation enzymes and reducing fruit softening. 相似文献