Mit der Ausgabe 2016/2017 (2019) wurde das Erscheinen eingestellt.

Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) by overexpression of the transcription factors OCT4, SOX2, KLF4, and c-Myc holds great promise for the development of personalized cell replacement therapies. In an attempt to minimize the risk of chromosomal disruption and to simplify reprogramming, several studies demonstrated that a reduced set of reprogramming factors is sufficient to generate iPSC. We recently showed that a reduction of reprogramming factors in murine cells not only reduces reprogramming efficiency but also may worsen subsequent differentiation. To prove whether this is also true for human cells, we compared the efficiency of neuronal differentiation of iPSC generated from fetal human neural stem cells with either one (OCT4; hiPSC1F-NSC) or two (OCT4, KLF4; hiPSC2F-NSC) reprogramming factors with iPSC produced from human fibroblasts using three (hiPSC3F-FIB) or four reprogramming factors (hiPSC4F-FIB). After four weeks of coculture with PA6 stromal cells, neuronal differentiation of hiPSC1F-NSC and hiPSC2F-NSC was as efficient as iPSC3F-FIB or iPSC4F-FIB. We conclude that a reduction of reprogramming factors in human cells does reduce reprogramming efficiency but does not alter subsequent differentiation into neural lineages. This is of importance for the development of future application of iPSC in cell replacement therapies.

Vocal tract morphology is an important factor in voice production. Its analysis has potential implications for educational matters as well as medical issues like voice therapy. The knowledge of the complex adjustments in the spatial geometry of the vocal tract during phonation is still limited. For a major part, this is due to difficulties in acquiring geometry data of the vocal tract in the process of voice production. In this study, a centerline-based segmentation method using active contours was introduced to extract the geometry data of the vocal tract obtained with MRI during sustained vowel phonation. The applied semiautomatic algorithm was found to be time- and interaction-efficient and allowed performing various three-dimensional measurements on the resulting model. The method is suitable for an improved detailed analysis of the vocal tract morphology during speech or singing which might give some insights into the underlying mechanical processes.

Dresdner Universitätsjournal vom 14. Juli 2015

Amniotic membrane is applied to the diseased ocular surface to stimulate wound healing and tissue repair, because it releases supportive growth factors and cytokines. These effects fade within about a week after application, necessitating repeated application. Generally, amniotic membrane is fixed with sutures to the ocular surface, but surgical intervention at the inflamed or diseased site can be detrimental. Therefore, we have developed a system for the mounting of amniotic membrane between two rings for application to a diseased ocular surface without surgical intervention (sutureless amniotic membrane transplantation). With this system, AmnioClip, amniotic membrane can be applied like a large contact lens. First prototypes were tested in an experiment on oneself for wearing comfort. The final system was tested on 7 patients in a pilot study. A possible influence of the ring system on the biological effects of amniotic membrane was analyzed by histochemistry and by analyzing the expression of vascular endothelial growth factor-A (VEGF-A), hepatocyte growth factor (HGF), fibroblast growth factor 2 (FGF 2) and pigment epithelium-derived factor (PEDF) from amniotic membranes before and after therapeutic application. The final product, AmnioClip, showed good tolerance and did not impair the biological effects of amniotic membrane. VEGF-A and PEDF mRNA was expressed in amniotic membrane after storage and mounting before transplantation, but was undetectable after a 7-day application period. Consequently, transplantation of amniotic membranes with AmnioClip provides a sutureless and hence improved therapeutic strategy for corneal surface disorders.

The dual role of glycolytic enzymes in cytosol-located metabolic processes and in cell surface-mediated functions with an influence on virulence is described for various micro-organisms. Cell wall-less bacteria of the class Mollicutes including the common human pathogen Mycoplasma pneumoniae possess a reduced genome limiting the repertoire of virulence factors and metabolic pathways. After the initial contact of bacteria with cells of the respiratory epithelium via a specialized complex of adhesins and release of cell-damaging factors, surface-displayed glycolytic enzymes may facilitate the further interac-tion between host and microbe. In this study, we described detection of the four subunits of pyruvate dehydrogenase complex (PDHA-D) among the cytosolic and membrane-associated proteins of M.pneumoniae. Subunits of PDH were cloned, expressed and purified to produce specific polyclonal guinea pig antisera. Using colony blotting, fractionation of total proteins and immunofluorescence experiments, the surface localization of PDHA-C was demonstrated. All pecombinant PDH subunits are able to bind to HeLa cells and human plasminogen. These interactions can be specifically blocked by the corresponding polyclon-al antisera. In addition, an influence of ionic interactions on PDHC-binding to plasminogen as well as of lysine residues on the association of PDHA-D with plasminogen was confirmed. The PDHB subunit was shown to activate plasminogen and the PDHB-plasminogen complex induces degradation of human fibrinogen. Hence, our data indicate that the surface-associated PDH subunits might play a role in the pathogenesis of M.pneumoniae infections by interaction with human plasminogen.

Schriftenreihe hrsg. von den Professoren der Fachgruppe Betriebswirtschaftslehre der TU Dresden

The mechanisms of interaction between inorganic matter and biomolecules, as well as properties of resulting hybrids, are receiving growing interest due to the rapidly developing field of bionanotechnology. The majority of potential applications for metal-biohybrid structures require stability of these systems under vacuum conditions, where their chemistry is elusive, and may differ dramatically from the interaction between biomolecules and metal ions in vivo. Here we report for the first time a photoemission and X-ray absorption study of the formation of a hybrid metal-protein system, tracing step-by-step the chemical interactions between the protein and metals (Cu and Fe) in vacuo. Our experiments reveal stabilization of the enol form of peptide bonds as the result of protein-metal interactions for both metals. The resulting complex with copper appears to be rather stable. In contrast, the system with iron decomposes to form inorganic species like oxide, carbide, nitride, and cyanide.

The mechanisms of interaction between inorganic matter and biomolecules, as well as properties of resulting hybrids, are receiving growing interest due to the rapidly developing field of bionanotechnology. The majority of potential applications for metal-biohybrid structures require stability of these systems under vacuum conditions, where their chemistry is elusive, and may differ dramatically from the interaction between biomolecules and metal ions in vivo. Here we report for the first time a photoemission and X-ray absorption study of the formation of a hybrid metal-protein system, tracing step-by-step the chemical interactions between the protein and metals (Cu and Fe) in vacuo. Our experiments reveal stabilization of the enol form of peptide bonds as the result of protein-metal interactions for both metals. The resulting complex with copper appears to be rather stable. In contrast, the system with iron decomposes to form inorganic species like oxide, carbide, nitride, and cyanide.

Dresdner Universitätsjournal vom 14. Juli 2015