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The abundance of microorganisms with characteristic, physiological activities in aquatic sediment communities can be estimated either by direct differential counting on selective media or by making isolations followed by testing of the isolates. The two methods have been compared with regard to microorganisms performing hydrolyses of different compounds. The first method was used to examine the effect of a model ecocontaminant on the hydrolytic activities of the sediment population. 相似文献
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Species pools,community completeness and invasion: disentangling diversity effects on the establishment of native and alien species 下载免费PDF全文
Jonathan A. Bennett Kersti Riibak Ene Kook Ülle Reier Riin Tamme C. Guillermo Bueno Meelis Pärtel 《Ecology letters》2016,19(12):1496-1505
Invasion should decline with species richness, yet the relationship is inconsistent. Species richness, however, is a product of species pool size and biotic filtering. Invasion may increase with richness if large species pools represent weaker environmental filters. Measuring species pool size and the proportion realised locally (completeness) may clarify diversity‐invasion relationships by separating environmental and biotic effects, especially if species’ life‐history stage and origin are accounted for. To test these relationships, we added seeds and transplants of 15 native and alien species into 29 grasslands. Species pool size and completeness explained more variation in invasion than richness alone. Although results varied between native and alien species, seed establishment and biotic resistance to transplants increased with species pool size, whereas transplant growth and biotic resistance to seeds increased with completeness. Consequently, species pools and completeness represent multiple independent processes affecting invasion; accounting for these processes improves our understanding of invasion. 相似文献
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Tiiu Kullisaar Jelena Shepetova Kersti Zilmer Epp Songisepp Aune Rehema Marika Mikelsaar Mihkel Zilmer 《Central European Journal of Biology》2011,6(1):32-40
Reducing postprandial oxidative stress (OxS), decreasing postprandial blood triglyceride level (TG) and improving lipoprotein
status is likely to have a preventive impact on the development of cardiovascular disease (CVD). Previously we have shown
that the antioxidant probiotic Lactobacillus fermentum ME-3 (DSM14241) is characterized by antiatherogenic effects. This randomized double-blind placebo-controlled study evaluated
the influence of kefir enriched with an antioxidative probiotic L. fermentum ME-3 (LfKef) on postprandial OxS, blood TG response and lipoprotein status. 100 clinically healthy subjects were recruited
into the study. Blood parameters of postprandial OxS, TG and lipoprotein status were determined by oxidized LDL, baseline
diene conjugation in LDL (BDC-LDL), oxidized LDL complex with beta-2 glycoprotein (Beta2-GPI-oxLDL), paraoxonase (PON) activity,
LDL-Chol, HDL-Chol and TG. To evaluate general body postprandial OxS-load we measured 8-isoprostanes (8-EPI) in the urine.
Consumption of LfKef significantly reduced the postprandial level of oxidized LDL, BDC-LDL, Beta2-GPI-oxLDL, urinary 8-isoprostanes
and postprandial TG and caused a significant increase in HDL-Chol and PON activity. This is the first evidence that kefir
enriched with an antioxidant probiotic may have a positive effect on both postprandial OxS and TG response as well as on lipoprotein
status. 相似文献
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Aleksandr Klepinin Vladimir Chekulayev Natalja Timohhina Igor Shevchuk Kersti Tepp Andrus Kaldma Andre Koit Valdur Saks Tuuli Kaambre 《Journal of bioenergetics and biomembranes》2014,46(1):17-31
The aim of the present study is to clarify some aspects of the mechanisms of regulation of mitochondrial metabolism in neuroblastoma (NB) cells. Experiments were performed on murine Neuro-2a (N2a) cell line, and the same cells differentiated by all-trans-retinoic acid (dN2a) served as in vitro model of normal neurons. Oxygraphy and Metabolic Control Analysis (MCA) were applied to characterize the function of mitochondrial oxidative phosphorylation (OXPHOS) in NB cells. Flux control coefficients (FCCs) for components of the OXPHOS system were determined using titration studies with specific non-competitive inhibitors in the presence of exogenously added ADP. Respiration rates of undifferentiated Neuro-2a cells (uN2a) and the FCC of Complex-II in these cells were found to be considerably lower than those in dN2a cells. Our results show that NB is not an exclusively glycolytic tumor and could produce a considerable part of ATP via OXPHOS. Two important enzymes - hexokinase-2 and adenylate kinase-2 can play a role in the generation of ATP in NB cells. MCA has shown that in uN2a cells the key sites in the regulation of OXPHOS are complexes I, II and IV, whereas in dN2a cells complexes II and IV. Results obtained for the phosphate and adenine nucleotide carriers showed that in dN2a cells these carriers exerted lower control over the OXPHOS than in undifferentiated cells. The sum of FCCs for both types of NB cells was found to exceed significantly that for normal cells suggesting that in these cells the respiratory chain was somehow reorganized or assembled into large supercomplexes. 相似文献
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Natalia Timohhina Rita Guzun Kersti Tepp Claire Monge Minna Varikmaa Heiki Vija Peeter Sikk Tuuli Kaambre Dan Sackett Valdur Saks 《Journal of bioenergetics and biomembranes》2009,41(3):259-275
The aim of this study was to measure energy fluxes from mitochondria in isolated permeabilized cardiomyocytes. Respiration
of permeabilized cardiomyocytes and mitochondrial membrane potential were measured in presence of MgATP, pyruvate kinase –
phosphoenolpyruvate and creatine. ATP and phosphocreatine concentrations in medium surrounding cardiomyocytes were determined.
While ATP concentration did not change in time, mitochondria effectively produced phosphocreatine (PCr) with PCr/O2 ratio equal to 5.68 ± 0.14. Addition of heterodimeric tubulin to isolated mitochondria was found to increase apparent Km
for exogenous ADP from 11 ± 2 μM to 330 ± 47 μM, but creatine again decreased it to 23 ± 6 μM. These results show directly
that under physiological conditions the major energy carrier from mitochondria into cytoplasm is PCr, produced by mitochondrial
creatine kinase (MtCK), which functional coupling to adenine nucleotide translocase is enhanced by selective limitation of
permeability of mitochondrial outer membrane within supercomplex ATP Synthasome-MtCK-VDAC-tubulin, Mitochondrial Interactosome. 相似文献
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Soini Sirpa; Ibarreta Dolores; Anastasiadou Violetta; Ayme Segolene; Braga Suzanne; Cornel Martina; Coviello Domenico A.; Evers-Kiebooms Gerry; Geraedts Joep; Gianaroli Luca; Harper Joyce; Kosztolanyi Gyorgy; Lundin Kersti; Rodrigues-Cerezo Emilio; Sermon Karen; Sequeiros Jorge; Tranebjaerg Lisbeth; Kaariainen Helena 《ESHRE Monographs》2006,2006(1):2-51
19 To whom correspondence should be addressed at: Department of Medical Genetics, University of Turku, Kiinamyllykatu 10, FIN-20520 Turku, Finland. E-mail: hkaaria{at}utu.fi* Reprinted from European Journal of Human Genetics (2006) 158 with permission. The views expressed in this study do not necessarily reflect those of the European Commission (EC). The interface between assisted reproductive technologies (ART)and genetics comprises several sensitive and important issuesthat affect infertile couples, families with severe geneticdiseases, potential children, professionals in ART and genetics,health care, researchers and the society in general. Geneticcauses have a considerable involvement in infertility. Geneticconditions may also be transmitted to the offspring and hencecreate transgenerational infertility or other serious healthproblems. Several studies also suggest a slightly elevated riskof birth defects in children born following ART. PGD has becomewidely practiced throughout the world for various medical indications,but its limits are being debated. The attitudes towards ARTand PGD vary substantially within Europe. The purpose of thisarticle was to outline a framework for development of guidelinesto be issued jointly by European Society of Human Genetics (ESHG)and European Society of Human Reproduction and Embryology (ESHRE)for the interface between genetics and ART. Technical, social,ethical and legal issues of ART and genetics will be reviewed. 相似文献
48.
Lilleväli K Haugas M Matilainen T Pussinen C Karis A Salminen M 《Mechanisms of development》2006,123(6):415-429
Inner ear develops from an induced surface ectoderm placode that invaginates and closes to form the otic vesicle, which then undergoes a complex morphogenetic process to form the membranous labyrinth. Inner ear morphogenesis is severely affected in Gata3 deficient mouse embryos, but the onset and basis of the phenotype has not been known. We show here that Gata3 deficiency leads to severe and unique abnormalities during otic placode invagination. The invagination problems are accompanied often by the formation of a morphological boundary between the dorsal and ventral otic cup and by the precocious appearance of dorsal endolymphatic characteristics. In addition, the endolymphatic domain often detaches from the rest of the otic epithelium during epithelial closure. The expression of several cell adhesion mediating genes is altered in Gata3 deficient ears suggesting that Gata3 controls adhesion and morphogenetic movements in early otic epithelium. Inactivation of Gata3 leads also to a loss of Fgf10 expression in otic epithelium and auditory ganglion demonstrating that Gata3 is an important regulator of Fgf-signalling during otic development. 相似文献
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