Search results for "Phosphor"

Theoretical studies on the spectroscopy of the 7-azaindole monomer and dimer

2001

The absorption and the emission spectra, both fluorescence and phosphorescence, of the 7-azaindole molecule have been studied by means of the complete active space (CAS) SCF method and multiconfigurational second-order perturbation theory (CASPT2). Excitation energies, oscillator strengths, dipole moments, transition dipole moments, and their directions have been computed and the results compared to those of analogous molecules such as indene, indole, and benzimidazole, to get a homogeneous picture of the photophysics of the systems. The absorption and emission of the 7-azaindole dimer and its related tautomer have also been computed in order to get further insight into the double fluoresce…

Fast Regulation of Cytochrome P450 Activities by Phosphorylation and Consequences for Drug Metabolism and Toxicity

2002

In contrast to the well-known regulation of cytochrome P450 (CYP) activity by enzyme induction, which represents a process with slow onset and slow offset, more recent studies revealed phosphorylation as a fast (within observation instantaneous) and isoenzyme-selective regulation. The phosphorylated enzyme (investigated isozyme: CYP2B1) was fully inactive. The phosphorylation is mediated by PKA and hence under control of hormones and drugs that alter cellular cAMP levels. The consequences for the metabolic control of toxic species derived from drugs and environmental carcinogens are discussed. This information will help to improve therapy with drugs metabolized by CYPs which are phosphoryla…

EGFL7 ligates αvβ3 integrin to enhance vessel formation

2013

Angiogenesis, defined as blood vessel formation from a preexisting vasculature, is governed by multiple signal cascades including integrin receptors, in particular integrin αVβ3. Here we identify the endothelial cell (EC)-secreted factor epidermal growth factor-like protein 7 (EGFL7) as a novel specific ligand of integrin αVβ3, thus providing mechanistic insight into its proangiogenic actions in vitro and in vivo. Specifically, EGFL7 attaches to the extracellular matrix and by its interaction with integrin αVβ3 increases the motility of EC, which allows EC to move on a sticky underground during vessel remodeling. We provide evidence that the deregulation of EGFL7 in zebrafish embryos leads …

Pathway network inference from gene expression data

2014

[EN] Background: The development of high-throughput omics technologies enabled genome-wide measurements of the activity of cellular elements and provides the analytical resources for the progress of the Systems Biology discipline. Analysis and interpretation of gene expression data has evolved from the gene to the pathway and interaction level, i.e. from the detection of differentially expressed genes, to the establishment of gene interaction networks and the identification of enriched functional categories. Still, the understanding of biological systems requires a further level of analysis that addresses the characterization of the interaction between functional modules. Results: We presen…

Growth of pikeperch in relation to lake characteristics: total phosphorus, water colour, lake area and depth

2003

The growth of pikeperch Sander lucioperca was studied in 41 lakes in central Finland. The backcalculated average total length of 3 year-old pikeperch was used as an indicator of growth. The growth correlated positively with total phosphorus and water colour and negatively with lake area and depth. The reason for differences in growth may be differences in the amount of suitable food, foraging success or temperature dynamics in different lakes.

Toxicity assessment of pesticides using the microtox test: application to environmental samples.

1997

Environmental Benefit of Improving Wastewater Quality: A Shadow Prices Approach for Sensitive Areas

2018

The use of effluents from wastewater treatment plants (WWTPs) as a non-conventional source of water for wetlands in arid and semi-arid regions is becoming the most-often sought solution for maintaining water flow in sensitive wetlands there. However, the managing effluent quality should be a requirement because excess nutrients (mainly nitrogen and phosphorus) can generate eutrophication problems in wetlands. In the Mediterranean area in general, wetlands are strongly vulnerable to eutrophication, which is why they are classified as sensitive areas. Our study uses a data set from 24 WWTPs, effluents of which are discharged to wetlands in the coast of Community of Valencia. We use the shado…

Effects of nitrogen enrichment on zooplankton biomass and N:P recycling ratios across a DOC gradient in northern-latitude lakes

2021

AbstractWe used data from whole-lake studies to assess how changes in food quantity (phytoplankton biomass) and quality (phytoplankton community composition, seston C:P and N:P) with N fertilization affect zooplankton biomass, community composition and C:N:P stoichiometry, and their N:P recycling ratio along a gradient in lake DOC concentrations. We found that despite major differences in phytoplankton biomass with DOC (unimodal distributions, especially with N fertilization), no major differences in zooplankton biomass were detectable. Instead, phytoplankton to zooplankton biomass ratios were high, especially at intermediate DOC and after N fertilization, implying low trophic transfer effi…

ETD and ECD Mass Spectrometry Fragmentation for the Characterization of Protein Post Translational Modifications

2012

The introduction of electron capture dissociation (ECD) by McLafferty and co-workers, and further of electron transfer dissociation (ETD), mechanism allows gas-phase fragmentation of multiply charged protein and peptide ions upon capture of a low-energy (<1 eV) electron or electron transfer in a gas phase ion-ion chemistry. The odd-electron species then undergoes rearrangement with subsequent cleavage of N−Cα backbone. Peptide fragmentation can take place inducing the formation of cand ztype fragment ions without loss of the information on the PTM localization. The key to the success of this approach is the selection of intact protein molecular ions and its profound potential for PTM charac…

A comparative investigation of DNA adducts, DNA strand breaks and gene mutations induced by benzo[a]pyrene and (+/-)-anti-benzo[a]pyrene-7,8-diol 9,1…

1997

Abstract Genotoxic effects of benzo[ a ]pyrene (BP) and its reactive metabolites (±)- anti -benzo[ a ]pyrene-7,8-diol 9,10-oxide ((±)- anti -BPDE) were comparatively investigated in vitro with the permanent human fibroblast cell line MRC5CV1. Induced DNA adducts were measured by 32 P-postlabeling, DNA strand breakage was determined by the comet assay and the HPRT gene mutation test was used to detect cytotoxicity and mutagenicity. Treatment of MRC5CV1 cells with S9 mix-activated BP or with (±)- anti -BPDE resulted in a concentration-dependent increase in DNA adducts and strand breaks. Genotoxic effects of BP and (±)- anti- BPDE were detected by 32 P-postlabeling and the comet assay with sim…