Occupational exposure to veterinary antibiotics: Pharmacokinetics of enrofloxacin in humans after dermal, inhalation and oral uptake - A clinical study.

Occupational exposure to veterinary antibiotics in hen houses at poultry feeding farms was demonstrated by biomonitoring campaigns in the past. The objective of this study was to investigate pharmacokinetics of three uptake routes: dermal, oral and inhaled. In an open-label cross-over study, six healthy volunteers were exposed to single occupational relevant doses of enrofloxacin.

Metallomics Study in Plants Exposed to Arsenic, Mercury, Selenium and Sulphur.

This chapter is focussing on the interaction of arsenic, mercury and selenium with plans. Aspects of biotransformations are discussed, before the analytical methodologies are listed and critically appraised in the second part. A holistic view is given, starting from the soil environment and continuing to the plant roots and the translocations into the upper part of the plants.

Solvent Transfer-Efficiency of Risk Management Measures.

A series of laboratory simulations were conducted in order to determine the airborne protection that might be afforded by different combinations of workplace exposure controls typically encountered when handling volatile solvents (e.g. solvent transfer).

A High-Throughput Method for the Quantitative Determination of Free Amino Acids in by Hydrophilic Interaction Chromatography-Tandem Mass Spectrometry.

Amino acids are the building blocks for protein synthesis and the precursors for many biomolecules, such as glutathione and -adenosylmethionine. Their intracellular concentrations provide valuable information about the overall metabolic state of the cell, as they are closely connected to carbon and nitrogen metabolism and are tightly regulated to meet cellular demands in ever-changing environments. Here, we describe a fast and simple method enabling metabolic profiling for free amino acids for large numbers of yeast strains.

Tpo1-mediated spermine and spermidine export controls cell cycle delay and times antioxidant protein expression during the oxidative stress response.

Cells counteract oxidative stress by altering metabolism, cell cycle and gene expression. However, the mechanisms that coordinate these adaptations are only marginally understood. Here we provide evidence that timing of these responses in yeast requires export of the polyamines spermidine and spermine.

Pyruvate kinase is a dosage-dependent regulator of cellular amino acid homeostasis.

The glycolytic enzyme pyruvate kinase (PK) is required for cancer development, and has been implicated in the metabolic transition from oxidative to fermentative metabolism, the Warburg effect. However, the global metabolic response that follows changes in PK activity is not yet fully understood. Using shotgun proteomics, we identified 31 yeast proteins that were regulated in a PK-dependent manner.

Histaminylation of glutamine residues is a novel posttranslational modification implicated in G-protein signaling.

Posttranslational modifications (PTM) have been shown to be essential for protein function and signaling. Here we report the identification of a novel modification, protein transfer of histamine, and provide evidence for its function in G protein signaling. Histamine, known as neurotransmitter and mediator of the inflammatory response, was found incorporated into mastocytoma proteins.

Pyruvate kinase triggers a metabolic feedback loop that controls redox metabolism in respiring cells.

In proliferating cells, a transition from aerobic to anaerobic metabolism is known as the Warburg effect, whose reversal inhibits cancer cell proliferation. Studying its regulator pyruvate kinase (PYK) in yeast, we discovered that central metabolism is self-adapting to synchronize redox metabolism when respiration is activated. Low PYK activity activated yeast respiration.

No evidence for a shift in pyruvate kinase PKM1 to PKM2 expression during tumorigenesis.

The Warburg effect describes the circumstance that tumor cells preferentially use glycolysis rather than oxidative phosphorylation for energy production. It has been reported that this metabolic reconfiguration originates from a switch in the expression of alternative splice forms (PKM1 and PKM2) of the glycolytic enzyme pyruvate kinase (PK), which is also important for malignant transformation.However, analytical evidence for this assumption was still lacking.

Monitoring protein expression in whole-cell extracts by targeted label- and standard-free LC-MS/MS.

Targeted quantification of proteins is a daily task in biological research but often relies on techniques such as western blotting that are only barely quantitative. Here we present a broadly applicable workflow for protein quantification from unpurified whole-cell extracts that can be completed in less than 3 d. Without prefractionation or affinity enrichment, a whole-cell extract is trypsin-digested in an acetonitrile-containing ammonium carbonate buffer and high-molecular-weight compounds are removed by filtration.

The pentose phosphate pathway is a metabolic redox sensor and regulates transcription during the antioxidant response.

Aims: A shift in primary carbon metabolism is the fastest response to oxidative stress. Induced within seconds, it precedes transcriptional regulation, and produces reducing equivalents in form of NADPH within the pentose phosphate pathway (PPP).

Results: Here, we provide evidence for a regulatory signaling function of this metabolic transition in yeast.

A new dominant peroxiredoxin allele identified by whole-genome re-sequencing of random mutagenized yeast causes oxidant-resistance and premature aging.

The combination of functional genomics with next generation sequencing facilitates new experimental strategies for addressing complex biological phenomena. Here, we report the identification of a gain-of-function allele of peroxiredoxin (thioredoxin peroxidase, Tsa1p) via whole-genome re-sequencing of a dominantSaccharomyces cerevisiae mutant obtained by chemical mutagenesis. Yeast strain K6001, a screening system for lifespan phenotypes, was treated with ethyl methanesulfonate (EMS).

The difference between rare and exceptionally rare: molecular characterization of ribose 5-phosphate isomerase deficiency.

Ribose 5-phosphate isomerase (RPI) deficiency is an enzymopathy of the pentose phosphate pathway. It manifests with progressive leukoencephalopathy and peripheral neuropathy and belongs, with one sole diagnosed case, to the rarest human disorders. The single patient was found compound heterozygous for a RPI frameshift and a missense (RPI(Ala61Val)) allele.

Stability of arsenic peptides in plant extracts: off-line versus on-line parallel elemental and molecular mass spectrometric detection for liquid chromatographic separation.

The instability of metal and metalloid complexes during analytical processes has always been an issue of an uncertainty regarding their speciation in plant extracts. Two different speciation protocols were compared regarding the analysis of arsenic phytochelatin (As(III)PC) complexes in fresh plant material. As the final step for separation/detection both methods used RP-HPLC simultaneously coupled to ICP-MS and ES-MS.

Can we trust mass spectrometry for determination of arsenic peptides in plants: comparison of LC-ICP-MS and LC-ES-MS/ICP-MS with XANES/EXAFS in analysis of Thunbergia alata.

The weakest step in the analytical procedure for speciation analysis is extraction from a biological material into an aqueous solution which undergoes HPLC separation and then simultaneous online detection by elemental and molecular mass spectrometry (ICP-MS/ES-MS). This paper describes a study to determine the speciation of arsenic and, in particular, the arsenite phytochelatin complexes in the root from an ornamental garden plant Thunbergia alata exposed to 1 mg As L(-1) as arsenate. The approach of formic acid extraction followed by HPLC-ES-MS/ICP-MS identified different As(III)-PC complexes in the extract of this plant and made their quantification via sulfur (m/z 32) and arsenic (m/z 75) possible.