Studies

Conversion from KEGG Reactome Information to SBTOOLBOX2 format.

Flux will be measured using the metabolomics platforms based on absolute quantification method (isotope ratio based MS technique) by LC-MS, using heavy-isotope labelled precursors of the metabolites of interest. For example, 15N labelled cysteine, glycine and glutamate will be used to determine rates of synthesis of glutathione. 15N-labelled methionine to measure S-adenosyl methionine (and its decarboxylated form, as well as methionine cycle intermediates). 15N labelled arginine is used as precursor ...

In addition to the highly targeted quantification of metabolites already known to play major roles in oxidative stress, to provide data directly compatible with current models, we will also take an untargeted metabolomics approach. This will enable us to identify other areas of the metabolome influenced by, or influencing, oxidative stress and will allow us to compare changes in each of the stress-inducing stimuli. We have recently pioneered untargeted metabolite profiling of T. brucei using ...

We have already demonstrated that the key metabolites of polyamine biosynthesis (arginine, ornithine, putrescine and spermidine) can be identified using HILIC chromatography coupled to the Orbitrap mass spectrometer, as can glycine, glutamate and cysteine used in glutathione biosynthesis, glutathionyl spermidine and trypanothione itself. Furthermore the key metabolites of the methionine cycle (methionine, S-adenosyl methionine, decarboxylated S-adenosyl methionine, methylthioadenosine) can all ...

Annotation retrieval

Creation of the KEGG based Reactome

Parasites will be harvested at different growth phases and the total amount of the proteins will be followed by western blot. The absolut concentration will be obtained by comparison with a know amount of the recombinant untagged protein. The thiol redox state of the proteins will be followed by modification of the free cys with methoxy-ethyl-maleinimide poly(ethylenglycol) (Meo-PEG-mal).

The enzymes involved in the trypanothione metabolism will be studied in a uniform assay medium that mimics the intracellular milieu of the parasite.

Key enzymes of critical points in the pathways will be targeted for disruption by the generation of RNAi cell lines and lines which drive tetracycline-regulatable ectopic over expression of either wild type enzyme or, if appropriate, dominant-negative or mis-targeted mutants of these. In all cases perturbed lines will be analysed with respect to the mRNA, protein or enzymatic activities of other components of the subsystem, this being directed iteratively by the predictions from systems modelling. ...

We developed a new metabolomics protocol, which involved a comparison of different harvesting techniques, quenching solutions and extraction methods.

The Lactate dehydrogenases (LDH) are key metabolic enzymes in lactic acid bacteria (LAB). The LDH ( E.C. 1.1.1.27) catalyzes the reaction of pyruvate and NADH into lactate and NAD+.We have carried out an experimental and computational study of the effects of fructose-1,6-bisphosphate (FBP), phosphate (Pi) and ionic strength (NaCl concentration) on 3 LDHs from 3 LABs studied at pH 6 and pH 7.

During the last few years scientists became increasingly aware that average data obtained from microbial population based experiments are not representative of the behavior, status or phenotype of single cells. Due to this new insight the number of single cell studies rises continuously (for recent reviews see (1,2,3)). However, many of the single cell techniques applied do not allow monitoring the development and behavior of one specific single cell in time (e.g. flow cytometry or standard ...

The output of the initial model of redox metabolism will be compared to experimental flux and metabolite data. Deviations between model and experiment will be prioritized together with WP2. We will apply Metabolic Control Analysis (Fell 1992 PMID: 1530563) to diagnose which enzymes control the deviating metabolite concentrations and/or rates. When the agreement between model and experiment is sufficient we will first link it to the existing model of trypanosome glycolysis and repeat the same ...

Our current gene-expression model (Haanstra et al. 2008 PMID: 19008351) will be parameterized for the different genes of interest. The framework of this gene expression model has been used to include mRNA half life data into the model of glycolysis For the enzymes of redox metabolism we will use newly measured rates of transcription, RNA precursor degradation, mRNA degradation, concentrations of mature mRNAs and proteins, enzyme turnover, Vmax values and metabolic fluxes (WP3&5). Regulation ...

We are in the process of construct an ODE model of the trypanothione pathway. As input we will use newly determined and existing kinetic data and measured metabolite concentrations at the boundaries (from WP3&6). Recently the glycolysis model was extended with the pentose phosphate pathway. This pathway will yield the NAPDH that maintains trypanothione in a reduced state. For some complex enzymes (i.e trypanothione synthase) we are intensively discussing the kinetic data obtained on the ...

These templates can be used for a selection of metabolomics data types. There is a MASTER template for general use and adaptation as well as several more specific templates for particular types of experiment (e.g. HPLC), or specific assay types (e.g glucose pulse)

Multi experimental approach to define the gene expression remodelling under potassium starvation conditions.

How does the Volume, internal pH, membrane potential and intracellular cation content change in a time dependent scale during potassium limitation.

How do the fluxes of rubidium (potassium) change during potassium starvation.

What is the proteome of starved cells. Main characteristics?

Are there one or several stationary states for physiological parameters dependent on external KCl? For which range of external potassium the cell is able to maintain a constant pH, potassium content, membrane potential and volume?

How does the current mediated by Trk1,2 depend on external and internal ion concentrations? How is the membrane potential shifted by the concentrations of various ions, especially ammonium?