Leukemia inhibitory factor (LIF) is a polyfunctional cytokine with numerous regulatory effects in vivo and in vitro. In murine stem cell cultures it is the essential media supplement for the maintenance of pluripotency of embryonic and induced pluripotent stem cells. To explore if the glycosylation and/or other post-translational modifications are affecting this activity, we produced and isolated LIF from either eucaryotic cells (Chinese hamster ovary (CHO) cells) or procaryotes (E.coli) and compared their biological activities in this study.

Notch signalling regulates arterial differentiation during embryonic development. The Notch ligand Delta-like 1 (Dll1) is known to be an essential regulator of postnatal arteriosclerosis (Limbourg et al. 2007). Clarification of its role within cardiac repair may lead to new ways of improving cardiovascular regeneration through targeted manipulation of cardiovascular differentiation. Since the soluble form leads to inactivation (Nichols et al. 2007), a fusion protein of the extracellular domain of the Notch ligand Delta-like 1 and the Fc region of IgG has been selected to be recombinantly produced in mammalian cells. CHOSFS cells were used as the expression system in this work. They were chemically transfected and cultured in serum-free medium under selective conditions. High-producing clones were gained by single-cell cloning via FACS and via dilution method. For FPLC-purification protein G as well as protein A columns were used. The activity was verified using a luciferase assay utilizing human umbilical cord vein endothelial cells (HUVEC).

One of the major aims of bioprocess engineering is the real-time monitoring of important process variables. This is the basis of precise process control and is essential for high productivity as well as the exact documentation of the overall production process. Infrared spectroscopy is a powerful analytical technique to analyze a wide variety of organic compounds. Thus, infrared sensors are ideal instruments for bioprocess monitoring. The sensors are non-invasive, have no time delay due to sensor response times, and have no influence on the bioprocess itself. No sampling is necessary, and several components can be analyzed simultaneously. In general, the direct monitoring of substrates, products, metabolites, as well as the biomass itself is possible. In this review article, insights are provided into the different applications of infrared spectroscopy for bioprocess monitoring and the complex data interpretation. Different analytical techniques are presented as well as example applications in different areas.

AbstractIn der Bioverfahrenstechnik ist es von entscheidender Bedeutung, Zustandsgrößen zeitnah zum tatsächlichen Prozess zu beobachten. Eine solche in situ‐Analyse ermöglicht eine akkurate Prozesssteuerung und trägt somit zur Erhöhung der Produktivität sowie der Reproduzierbarkeit bei. Ebenso lassen sich durch eine optimierte Steuerung Verbrauchskosten senken. Molekülschwingungen vieler organischer Verbindungen zeigen spektrale Signaturen im IR‐Bereich. Aufgrund dessen bieten sich für eine Prozessüberwachung verschiedene Infrarotsensoren an. Durch die Verwendung dieser nicht‐invasiven, optischen Sensoren ist gewährleistet, dass die Messungen keinen Einfluss auf den Kultivierungsvorgang haben. Das Kultivierungsmedium wird weder durch Probenentnahme verbraucht, noch beeinflusst. Es können unterschiedlichste chemische Komponenten des Kultivierungsmediums erfasst werden. Dazu gehören Nährstoffe, Wachstumsfaktoren und verschiedene Metabolite sowie die Biomasse selbst. Dieser Übersichtsartikel bietet einen Einblick in die verschiedenen Anwendungen der Infrarotspektroskopie im Bereich der Bioprozesstechnik. Es werden die verschiedenen Techniken dieser Methode aufgeführt sowie eine Überblick über aktuelle Arbeiten gegeben.

Notch signalling regulates arterial differentiation during embryonic development. The Notch ligand Delta-like 1 (Dll1) is known to be an essential regulator of postnatal arteriosclerosis (Limbourg et al. 2007). Clarification of its role within cardiac repair may lead to new ways of improving cardiovascular regeneration through targeted manipulation of cardiovascular differentiation. Since the soluble form leads to inactivation (Nichols et al. 2007), a fusion protein of the extracellular domain of the Notch ligand Delta-like 1 and the Fc region of IgG has been selected to be recombinantly produced in mammalian cells. CHOSFS cells were used as the expression system in this work. They were chemically transfected and cultured in serum-free medium under selective conditions. High-producing clones were gained by single-cell cloning via FACS and via dilution method. For FPLC-purification protein G as well as protein A columns were used. The activity was verified using a luciferase assay utilizing human umbilical cord vein endothelial cells (HUVEC).