Mechanisms of adaptive Growth and Differentiation in Animal Cells
Many transmitter-, hormone- or growth factor receptors on the surface of animal cells are coupled to signal transduction pathways involving second messengers or protein kinases. Alterations in cytosolic concentrations of second messengers or in protein phosphorylation levels of certain proteins result in functional changes in cells, e.g. activation of secretion, changes in cell shape etc. In the long term, altered rates of transcription of specific genes (changes in the transcriptome) may result from such signaling processes which sometimes translate into altered protein abundances (changes in the proteome). Such modifications may affect basal cellular processes like cell proliferation or cell differentiation.
We investigate such signaling cascades and the cell physiological consequences of their activation using different model systems (salt gland tissue from ducklings, Anas platyrhynchos; mammalian liver tissue, or human airway epithelial cells).
Methods used are: Protein Biochemistry (1D or 2D Gel Electrophoresis), Western Blotting, Immune Fluorescence, Live Cell Microscopy, second messenger-Analysis, Measurements of Transepithelial Voltage or Resistance, Measurement of Changes in intracellular Ion Concentrations and Plasma Membrane Potential, Analysis of DNA or RNA, cDNA-Cloning and Protein Expression, Enzyme Assays
Cell Physiological Effects of Virulence-associated Factors of Staphylococcus aureus on human Airway Epithelial Cells
Human airway epithelial cells are the first line of defense against air-bourne dust particles or microorganisms that get inhaled. Because our airways are lined with a relatively thick mucus layer, such agents normally do not get in direct contact with the surfaces of the airway epithelial cells. However, if the mucociliary clearance of the airway is not efficient (viral infection, cystic fibrosis), bacteria may stay long enough in the mucus layer of the airways to generate virulence-associated factors. These are small, highly diffusible molecules that readily pass through the mucus layer and may affect airway epithelial cell function.
We use bacterial culture supernatants or isolated recombinant virulence factors of Staphylococcus aureus to study the effects of these agents on cellular performance and parameters in cultured airway epithelial cells (immortalized human cells or freshly prepared cells). The focus is on signaling pathways (second messengers, MAP kinases) and gene regulatory effects (transcription factors, mRNAs) and protein expression associated with altered cell function (e.g. cytokine- and chemokine secretion, cell-cell- or cell-matrix-adhesion).
Methods used are: Protein Biochemistry (1D or 2D Gel Electrophoresis), Western Blotting, Immune Fluorescence, ELISA, Live Cell Microscopy (Time lapse), second messenger-Analysis, Measurements of Transepithelial Voltage or Resistance, Measurement of Changes in intracellular Ion Concentrations and Plasma Membrane Potential, Analysis of DNA or RNA, cDNA-Cloning and Protein Expression, Enzyme Assays
Structure and Function of the Salivary Gland Cells of Blood-feeding Leeches and their Proteaneous Ingredients
Hematophageous animals (e.g. the medicinal leech, Hirudo sp.) release salivary components into the host which function as analgetics or as anti-coagulants to name just two of many other functions. We investigate structure and function of the unicellular salivary glands in medicinal leeches and try to identify more of the many protein ingredients of leech saliva. Among these substances, there may be actually some with a potential to be used in medicine.
Methods used are: Protein Biochemistry (1D or 2D Gel Electrophoresis), Western Blotting, Immune Fluorescence, Histology, Analysis of DNA or RNA, cDNA-Cloning and Protein Expression, Enzyme Assays
Osmotolerance in the Freshwater and Brackish water Snail Theodoxus fluviatilis
Project A2 in the DFG Research Training Group 2010
We investigate the salinity tolerance of individuals of limnic or brackish water lineages of the nerite Theodoxus fluviatilis and the underlying mechanisms. These snails use their ability of increasing or decreasing concentrations of free amino acids as compatible osmolytes to balance their cell volumes under hyperosmotic or hypoosmotic stress, respectively. Plastic responses like these may enable these snails to cope with moderate salinity changes in their habitats. However, depending on the origin of the snails (freshwater or brackish water habitats) there may also be genetic adaptations that limit individuals of these lineages in their survival of alien conditions.
Methods used are: Common Garden-Experiments, Amino Acid Analyses, Protein Biochemistry (1D or 2D Gel Electrophoresis), Western Blotting, Analysis of DNA or RNA (Transcriptomics), cDNA-Cloning and Protein Expression, in situ-Hybridization