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991.
Audrey L. Mayer Leena Vihermaa Noora Nieminen Annukka Luomi Maximilian Posch 《Ecological Indicators》2009,9(5):992-1000
Novel systems combining bioindicators, models, and remote sensing are possible cost-effective methods to monitor regional-scale pollution. Epiphytic macrolichen communities have been widely used as air pollution bioindicators, however these communities are also affected by microclimate conditions as influenced by forest structure. We used the Finnish epiphytic macrolichen survey method SFS5670 to collect data in 27 spruce and birch dominated forests in southern Finland and northwestern Russia. The method measures the abundance and physiological damage of Hypogymnia physodes and Bryoria spp., and the frequency of 13 epiphytic macrolichen species of known sensitivity which can be used to calculate the widely used Index of Atmospheric Purity (IAP). The location of the sites represents an east–west gradient of air pollution conditions of SO2, SO42?, NO2, NH3 + NH4+, and HNO3 + NO3?. We also recorded living and dead forest structure characteristics at these sites, which we initially chose to be as similar as possible on either side of the border. Abundance and damage of H. physodes were correlated with forest structure but not with air pollution, indicating that these macrolichen variables may not be reliable bioindicators at low air pollution concentrations. However, the Index of Atmospheric Purity, calculated from observed presence/absence data of multiple epiphytic macrolichen species, was strongly correlated with sulfur and nitrogen pollutant concentrations. These results suggest that the IAP as calculated using data from the Finnish epiphytic macrolichen survey method may be a useful air pollution indicator in combination with modeled data, even in relatively clean regions. 相似文献
992.
993.
Background
Probiotic bacteria are thought to play an important role in the digestive system and therefore have to survive the passage from stomach to intestines. Recently, a novel approach to simulate the passage from stomach to intestines in a single bioreactor was developed. The advantage of this automated one reactor system was the ability to test the influence of acid, bile salts and pancreatin. 相似文献994.
Amber J. Tomasini Aaron D. Schuler John A. Zebala Alan N. Mayer 《Genesis (New York, N.Y. : 2000)》2009,47(11):736-743
Manipulating gene expression in zebrafish is critical for exploiting the full potential of this vertebrate model organism. Morpholino oligos are the most commonly used antisense technology for knocking down gene expression. However, morpholinos suffer from a lack of control over the timing and location of knockdown. In this report, we describe a novel light‐ activatable knockdown reagent called PhotoMorph?. PhotoMorphs can be generated from existing morpholinos by hybridization with a complementary caging strand containing a photocleavable linkage. The caging strand neutralizes the morpholino activity until irradiation of the PhotoMorph with UV light releases the morpholino. We generated PhotoMorphs to target genes encoding enhanced green fluorescent protein, No tail, and E‐cadherin to illustrate the utility of this approach. Temporal control of gene expression with PhotoMorphs permitted us to circumvent the early lethal phenotype of E‐cadherin knockdown. A splice‐blocking PhotoMorph directed to the rheb gene showed light‐dependent gene knockdown up to 72 hpf. PhotoMorphs thus offer a new class of laboratory reagents suitable for the spatiotemporal control of gene expression in the zebrafish. genesis 47:736–743, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
995.
Peter C. Huszthy Tsanan Giroglou Oleg Tsinkalovsky Philipp Euskirchen Kai Ove Skaftnesmo Rolf Bjerkvig Dorothee von Laer Hrvoje Miletic 《PloS one》2009,4(7)
Background
Glioblastoma is the most frequent and most malignant primary brain tumor with a poor prognosis. The translation of therapeutic strategies for glioblastoma from the experimental phase into the clinic has been limited by insufficient animal models, which lack important features of human tumors. Lentiviral gene therapy is an attractive therapeutic option for human glioblastoma, which we validated in a clinically relevant animal model.Methodology/Principal Findings
We used a rodent xenograft model that recapitulates the invasive and angiogenic features of human glioblastoma to analyze the transduction pattern and therapeutic efficacy of lentiviral pseudotyped vectors. Both, lymphocytic choriomeningitis virus glycoprotein (LCMV-GP) and vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped lentiviral vectors very efficiently transduced human glioblastoma cells in vitro and in vivo. In contrast, pseudotyped gammaretroviral vectors, similar to those evaluated for clinical therapy of glioblastoma, showed inefficient gene transfer in vitro and in vivo. Both pseudotyped lentiviral vectors transduced cancer stem-like cells characterized by their CD133-, nestin- and SOX2-expression, the ability to form spheroids in neural stem cell medium and to express astrocytic and neuronal differentiation markers under serum conditions. In a therapeutic approach using the suicide gene herpes simplex virus thymidine kinase (HSV-1-tk) fused to eGFP, both lentiviral vectors mediated a complete remission of solid tumors as seen on MRI resulting in a highly significant survival benefit (p<0.001) compared to control groups. In all recurrent tumors, surviving eGFP-positive tumor cells were found, advocating prodrug application for several cycles to even enhance and prolong the therapeutic effect.Conclusions/Significance
In conclusion, lentiviral pseudotyped vectors are promising candidates for gene therapy of glioma in patients. The inefficient gene delivery by gammaretroviral vectors is in line with the results obtained in clinical therapy for GBM and thus confirms the high reproducibility of the invasive glioma animal model for translational research. 相似文献996.
Mehdi Namdar Tiziano Schepis Pascal Koepfli Oliver Gaemperli Patrick T. Siegrist Renate Grathwohl Ines Valenta Raphael Delaloye Michael Klainguti Christophe A. Wyss Thomas F. Lüscher Philipp A. Kaufmann 《PloS one》2009,4(5)
Background
Caffeine is one of the most widely consumed pharmacologically active substances. Its acute effect on myocardial blood flow is widely unknown. Our aim was to assess the acute effect of caffeine in a dose corresponding to two cups of coffee on myocardial blood flow (MBF) in coronary artery disease (CAD).Methodology/Principal Findings
MBF was measured with 15O-labelled H2O and Positron Emission Tomography (PET) at rest and after supine bicycle exercise in controls (n = 15, mean age 58±13 years) and in CAD patients (n = 15, mean age 61±9 years). In the latter, regional MBF was assessed in segments subtended by stenotic and remote coronary arteries. All measurements were repeated fifty minutes after oral caffeine ingestion (200 mg). Myocardial perfusion reserve (MPR) was calculated as ratio of MBF during bicycle stress divided by MBF at rest. Resting MBF was not affected by caffeine in both groups. Exercise-induced MBF response decreased significantly after caffeine in controls (2.26±0.56 vs. 2.02±0.56, P<0.005), remote (2.40±0.70 vs. 1.78±0.46, P<0.001) and in stenotic segments (1.90±0.41 vs. 1.38±0.30, P<0.001). Caffeine decreased MPR significantly by 14% in controls (P<0.05 vs. baseline). In CAD patients MPR decreased by 18% (P<0.05 vs. baseline) in remote and by 25% in stenotic segments (P<0.01 vs. baseline).Conclusions
We conclude that caffeine impairs exercise-induced hyperaemic MBF response in patients with CAD to a greater degree than age-matched controls. 相似文献997.
Honckenya peploides is a subdioecious dune plant that reproduces both sexually and by clonal growth. In northwest Spain this species was found to exhibit an extreme spatial segregation of the sexes, and our objective was to investigate genetic variation in unisexual clumps. Genetic variation was studied in six unisexual clumps of H. peploides, three of them exclusively composed of males and three exclusively female. In total, 193 samples were analysed using isozyme analysis and 80 samples were analysed using two AFLP primer combinations. Both techniques revealed considerably high genetic diversity (average proportion of distinguishable genotypes: 0.22 for isozymes and 0.36 for AFLP; average Simpson’s D: 0.65 for isozymes and 0.68 for AFLP). Our results show that, in spite of clonal growth, each unisexual clump consists of different genotypes. Genetic diversity within clumps is similar for both sexual morphs. Reasons for unisexuality of the clumps are discussed. 相似文献
998.
Oberdoerffer P 《Nature cell biology》2010,12(11):1029-1031
Changes in chromatin structure are a conserved hallmark of ageing, and the mechanism driving these changes, as well as their functional significance, are heavily investigated. Loss of core histones is now observed in aged cells and may contribute to this phenomenon. Histone loss is coupled to cell division and seems to be triggered by telomeric DNA damage. 相似文献
999.
1000.
J. Ruiz‐Sanchez Z.R. Flores‐Bustamante L. Dendooven E. Favela‐Torres G. Soca‐Chafre J. Galindez‐Mayer L.B. Flores‐Cotera 《Journal of applied microbiology》2010,109(6):2144-2150
Aims: To determine in liquid (LF) and solid‐state fermentation (SSF) the effect of medium concentration on growth and Taxol produced by Nigrospora sp., a fungus isolated from the Mexican yew. Methods and Results: Nigrospora sp. was grown at different concentrations of the base culture medium M1D, i.e. two (2×), four (4×), six (6×) and eight times (8×) the base concentration. The titres of Taxol determined by competitive inhibition enzyme immunoassay increased with increasing medium concentration in LF and SSF but were higher in SSF in every medium concentration. The Taxol produced in SSF and LF with 8× medium was 221 and 142 ng l?1. The SSF gave also higher biomass, growth and sugar utilization than LF in every medium. The growth and sugar consumption were modelled by the logistic and the Pirt models, respectively. However, the Luedeking–Piret model was unsuitable for Taxol. Conclusions: The SSF surpassed LF in terms of Taxol, growth and sugar utilization; thus, it has significant advantages over LF. Significance and Impact of the Study: This is the first report on Taxol production by SSF and the first contribution to evaluate the influence of the medium on Taxol production in LF and SSF. 相似文献