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991.
992.
Urubschurov V Janczyk P Souffrant WB Freyer G Zeyner A 《FEMS microbiology ecology》2011,77(3):493-502
This study aimed to characterize the intestinal yeasts in weaning piglets and to establish their possible relationships with main bacterial groups. German Landrace piglets were weaned (WP, n=32) at 28 days of age or kept with the dams until day 39 without creep feed (UP, n=32). The experiment was performed at an experimental and a commercial farm (CF). Faeces were collected from the piglets, sows and pen floors on days 28, 33 and 39 for isolation of DNA and cultivation for enumeration of yeasts, enterobacteria, enterococci and lactobacilli. Fragments of the D1 domain of 26S rRNA gene were amplified and separated by denaturing gradient gel electrophoresis (DGGE). No yeasts could be cultured from water and feed samples. No or only low numbers of yeasts were detected among all UP. In WP at CF, yeasts correlated with lactobacilli (r=0.456; P=0.009) and enterobacteria (r=-0.407; P=0.021). Kazachstania slooffiae dominated among the cultured yeasts. It was the only yeast species detected by PCR-DGGE. Yeasts, especially K. slooffiae, established in the porcine gastrointestinal tract after consumption of grain-based feed and may interrelate with the intestinal microbiota. The study provides data indicating importance of K. slooffiae for the development of balanced porcine gut microbiota. 相似文献
993.
de Kloet AD Krause EG Scott KA Foster MT Herman JP Sakai RR Seeley RJ Woods SC 《American journal of physiology. Endocrinology and metabolism》2011,301(6):E1081-E1091
Considerable evidence implicates the renin-angiotensin system (RAS) in the regulation of energy balance. To evaluate the role of the RAS in the central nervous system regulation of energy balance, we used osmotic minipumps to chronically administer angiotensin II (Ang II; icv; 0.7 ng/min for 24 days) to adult male Long-Evans rats, resulting in reduced food intake, body weight gain, and adiposity. The decrease in body weight and adiposity occurred relative to both ad libitum- and pair-fed controls, implying that reduced food intake in and of itself does not underlie all of these effects. Consistent with this, rats administered Ang II had increased whole body heat production and oxygen consumption. Additionally, chronic icv Ang II increased uncoupling protein-1 and β(3)-adrenergic receptor expression in brown adipose tissue and β3-adrenergic receptor expression in white adipose tissue, which is suggestive of enhanced sympathetic activation and thermogenesis. Chronic icv Ang II also increased hypothalamic agouti-related peptide and decreased hypothalamic proopiomelanocortin expression, consistent with a state of energy deficit. Moreover, chronic icv Ang II increased the anorectic corticotrophin- and thyroid-releasing hormones within the hypothalamus. These results suggest that Ang II acts in the brain to promote negative energy balance and that contributing mechanisms include an alteration in the hypothalamic circuits regulating energy balance, a decrease in food intake, an increase in energy expenditure, and an increase in sympathetic activation of brown and white adipose tissue. 相似文献
994.
Johansson C Roos AK Montano SJ Sengupta R Filippakopoulos P Guo K von Delft F Holmgren A Oppermann U Kavanagh KL 《The Biochemical journal》2011,433(2):303-311
Human GLRX5 (glutaredoxin 5) is an evolutionarily conserved thiol-disulfide oxidoreductase that has a direct role in the maintenance of normal cytosolic and mitochondrial iron homoeostasis, and its expression affects haem biosynthesis and erythropoiesis. We have crystallized the human GLRX5 bound to two [2Fe-2S] clusters and four GSH molecules. The crystal structure revealed a tetrameric organization with the [2Fe-2S] clusters buried in the interior and shielded from the solvent by the conserved β1-α2 loop, Phe?? and the GSH molecules. Each [2Fe-2S] cluster is ligated by the N-terminal activesite cysteine (Cys??) thiols contributed by two protomers and two cysteine thiols from two GSH. The two subunits co-ordinating the cluster are in a more extended conformation compared with iron-sulfur-bound human GLRX2, and the intersubunit interactions are more extensive and involve conserved residues among monothiol GLRXs. Gel-filtration chromatography and analytical ultracentrifugation support a tetrameric organization of holo-GLRX5, whereas the apoprotein is monomeric. MS analyses revealed glutathionylation of the cysteine residues in the absence of the [2Fe-2S] cluster, which would protect them from further oxidation and possibly facilitate cluster transfer/acceptance. Apo-GLRX5 reduced glutathione mixed disulfides with a rate 100 times lower than did GLRX2 and was active as a glutathione-dependent electron donor for mammalian ribonucleotide reductase. 相似文献
995.
Lang E Qadri SM Zelenak C Gu S Rotte A Draeger A Lang F 《American journal of physiology. Cell physiology》2011,301(2):C490-C498
Blebbistatin, a myosin II inhibitor, interferes with myosin-actin interaction and microtubule assembly. By influencing cytoskeletal dynamics blebbistatin counteracts apoptosis of several types of nucleated cells. Even though lacking nuclei and mitochondria, erythrocytes may undergo suicidal cell death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Triggers of eryptosis include energy depletion and osmotic shock, which enhance cytosolic Ca(2+) activity with subsequent Ca(2+)-sensitive cell shrinkage and cell membrane scrambling. The present study explored the effect of blebbistatin on eryptosis. Cell membrane scrambling was estimated from binding of annexin V to phosphatidylserine at the erythrocyte surface, cell volume from forward scatter in fluorescence-activated cell sorting analysis and cytosolic Ca(2+) concentration from Fluo3 fluorescence. Exposure to blebbistatin on its own (1-50 μM) did not significantly modify cytosolic Ca(2+) concentration, forward scatter, or annexin V binding. Glucose depletion (48 h) was followed by a significant increase of Fluo3 fluorescence and annexin V binding, effects significantly blunted by blebbistatin (Fluo3 fluorescence ≥ 25 μM, annexin V binding ≥ 10 μM). Osmotic shock (addition of 550 mM sucrose) again significantly increased Fluo3 fluorescence and annexin binding, effects again significantly blunted by blebbistatin (Fluo3 fluorescence ≥ 25 μM, annexin V binding ≥ 25 μM). The present observations disclose a novel effect of blebbistatin, i.e., an influence on Ca(2+) entry and suicidal erythrocyte death following energy depletion and osmotic shock. 相似文献
996.
997.
Bioenergy potential of Ulva lactuca: biomass yield, methane production and combustion 总被引:2,自引:0,他引:2
Bruhn A Dahl J Nielsen HB Nikolaisen L Rasmussen MB Markager S Olesen B Arias C Jensen PD 《Bioresource technology》2011,102(3):2595-2604
The biomass production potential at temperate latitudes (56°N), and the quality of the biomass for energy production (anaerobic digestion to methane and direct combustion) were investigated for the green macroalgae, Ulva lactuca. The algae were cultivated in a land based facility demonstrating a production potential of 45 T (TS) ha−1 y−1. Biogas production from fresh and macerated U. lactuca yielded up to 271 ml CH4 g−1 VS, which is in the range of the methane production from cattle manure and land based energy crops, such as grass-clover. Drying of the biomass resulted in a 5-9-fold increase in weight specific methane production compared to wet biomass. Ash and alkali contents are the main challenges in the use of U. lactuca for direct combustion. Application of a bio-refinery concept could increase the economical value of the U. lactuca biomass as well as improve its suitability for production of bioenergy. 相似文献
998.
Tsompanidou E Sibbald MJ Chlebowicz MA Dreisbach A Back JW van Dijl JM Buist G Denham EL 《Journal of bacteriology》2011,193(5):1267-1272
The important human pathogen Staphylococcus aureus is known to spread on soft agar plates. Here, we show that colony spreading of S. aureus involves the agr quorum-sensing system. This finding can be related to the agr-dependent expression of biosurfactants, such as phenol-soluble modulins, suggesting a connection between spreading motility and virulence. 相似文献
999.
1000.
Climate change is already altering the magnitude and/or frequency of extreme events which will in turn affect plant fitness
more than any change in the average. Although the fingerprint of anthropogenic warming in recent phenological records is well
understood, the impacts of extreme events have been largely neglected. Thus, the temperature response of European phenological
records to warm and cold spells was studied using the COST725 database. We restricted our analysis to the period 1951–2004
due to better spatial coverage. Warm and cold spells were identified using monthly mean ENSEMBLES temperature data on a 0.5°
grid for Europe. Their phenological impact was assessed as anomalies from maps displaying mean onsets for 1930–1939. Our results
clearly exhibit continental cold spells predominating in the period 1951–1988, especially during the growing season, whereas
the period from 1989 onwards was mainly characterised by warm spells in all seasons. The impacts of these warm/cold spells
on the onset of phenological seasons differed strongly depending on species, phase and timing. “False” phases such as the
sowing of winter cereals hardly reacted to summer warm/cold spells; only the sowing of summer cereals mirrored spring temperature
warm/cold spells. The heading dates of winter cereals did not reveal any consistent results probably due to fewer warm/cold
spells identified in the relevant late spring months. Apple flowering and the harvest of winter cereals were the best indicators
of warm/cold spells in early spring and summer, also being spatially coherent with the patterns of warm/cold spells. 相似文献