04 Fakultät Energie-, Verfahrens- und Biotechnik
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Item Open Access Probleme der Gestaltbildung(1990) Kull, UlrichDie Einzelheiten der Bildung komplexer Gestalten von Lebewesen können nicht vollständig genetisch fixiert sein, da hierzu die Zahl der Gene der Organismen kaum ausreichen würde. Es muß also Vorgänge der Gestaltbildung geben, die auf grund weniger genetischer Festlegungen (Randbedingungen} unter Selbstorganisation ablaufen; sie sind "systemimmanente Eigenschaften". Ein besonderes schönes Beispiel dafür liefern die Radiolarien, die schon Haeckel der ästhetisch ansprechenden Skelettformen wegen sehr schätzte.Item Open Access Biophysical investigations of the in vitro effects of shock waves and ultrasound(1993) Brümmer, Franz; Suhr, Dierk; Irmer, Ulrich; Bachleitner, Christoph; Hülser, Dieter F.To investigate the interactions of ultrasonic waves with biological tissues, we developed and standardized several in vitro models. Using these systems - artificial stones, human erythrocytes, L1210 mouse leukemia cells, multicellular spheroids, cavitation assay - we are able to elucidate the mechanisms of interaction as well as the cause of clinically observed side effects.Item Open Access Biological effects of shock waves(1990) Brümmer, Franz; Bräuner, Thomas; Hülser, Dieter F.Extracorporeal shock wave lithotripsy has become established worldwide as the method of choice for the treatment of nephrolithiasis and ureterolithiasis over the last 10 years. Although initial studies showed no damaging effects of the shock waves on organs and tissues, numerous recent reports have presented evidence for severe acute effects and chronic complications after shock wave treatment. The pathophysiological effects on kidneys and the histopathological effects on organs or tissues in man and animal, and also the effects on cells in culture and tumors are sumarized. Suspended and immobilized cell cultures were used to characterize and quantify the efficacy of shock wave. Extended applications of shock waves and possible modifications to shock wave generators are discussed.Item Open Access Funktionen eines regionalen naturwissenschaftlichen Vereins(1994) Kull, UlrichDie Gesellschaft für Naturkunde in Württemberg blickt auf 150 Jahre zurück; sie wurde gegründet im Herbst 1844. Seit ihrer Gründung dient sie der Erforschung der heimischen Natur und der Verknüpfung der Ergebnisse mit den allgemeinen Fortschritten der Naturwissenschaften. Sie arbeitet vor allem im Bereich der Bio- und Geowissenschaften.Item Open Access Cytokinins in different cell compartments after treatment with [8-14C]-kinetin : [abstract](1985) Graf, Josef A.; Dietz, B.; Kull, Ulrich-Item Open Access Prosomes of higher plants share biochemical properties : [abstract](1988) Schliephacke, Martin; Kremp, Anette; Schmid, Hans-Peter; Kull, Ulrich-Item Open Access Introduction - Symposium on Intercellular Communication Stuttgart, 1982(1982) Hülser, Dieter F.Intercellular communication is a postulate of complex multicellular organisation. Signal transfer between cells is possible in different ways: 1.) Long distances of up to 1 m may be bridged by molecules which are produced in distinct cells and are released into the extracellular fluid where they are distributed and interact with receptors on the surface of their target cells (e.g., humoral interaction). 2.) Transmitter substances which have a limited life span or which can be inactivated by inhibitor molecules spread signals only over shorter distances (e.g., synaptic cleft, -200nm). 3.) Information can also be exchanged by direct membrane contact when two molecules interact with each other directly or via linker molecules (e.g., immune system). 4.) Intercellular communication is also possible by channels between adjacent cells, which permit the exchange of ions and molecules and the spread of electric currents; many of those pores are arranged in the membranes of the contacting cells as a quasicristalline structure forming the gap junction. A national symposium on "Intercellular Communication" in Stuttgart on 16 and 17 September 1982 serving the aim of increased "interlaboratory communication" covered most of the above aspects.Item Open Access Item Open Access Item Open Access Extraordinary biological membrane structures resulting from different local membrane curvatures(1992) Meyer, Helmut W.; Hülser, Dieter F.The bilayer arrangement of amphiphilic molecules is not only the basic structure of rather flat biological membranes, but also of regularly curved bilayers in most cubic phase structures. The basis of these cubic phase structures are infinite periodical minimal surfaces (IPMS). Extraordinary biological membrane structures resembling such IPMS were found as periodically curved bilayers in areas of the plasma membrane in a Streptomyces strain and in liposomes prepared from its extracted lipids. This structure consists of a transition of convex to concave curvatures and vice versa. A structure with curvatures in one direction only was observed in vacuolar membranes of yeast cells with a genetic defect. Our electron microscopical analysis of freeze fractured membranes of these cells revealed not only fully invaginated but also flat particle-free areas which were mainly circularly shaped, some elongated areas, however, were also present. In addition, sometimes periodical arrangements were detected which obviously are not related to IPMS structures. Both structures, however, indicate a high proportion of wedge-shaped lipid molecules in the bilayer.