Developments in biotechnology

This issue of EXPERIENTIA on ‘Developments in Biotechnology’ is dedicated to Professor Armin Fiechter who celebrated his 65th birthday in October. He is one of the most eminent promoters of biotechnology in Switzerland and he was instrumental in establishing the Institute for Biotechnology at ETH in 1982 of which he is still director. By pioneering the combination of fundamental and applied aspects he has greatly influenced the advancement of biotechnology in teaching and research in Switzerland. Distinguished scientists from various countries were invited to contribute to this special issue of EXPERIENTIA to review aspects of yeast physiology, process optimization and control, analytics, and applications. We are well aware that the articles presented here are only a narrow selection of the current activities in biotechnology but since Professor Fiechter has devoted most of his scientific career to research on yeast physiology, process development and instrumentation it is appropriate to focus this issue on these aspects. We thank all the authors who have contributed to mark this special event. Professor Fiechter continues to actively stimulate progress in biotechnology with a still lively awareness of future developments. May he continue to persue his objectives and, together with Mrs. Fiechter, enjoy the time to come.     

Compte rendu des publications

Cellular and Molecular Life Sciences -     

Vaspin inhibits kallikrein 7 by serpin mechanism

The molecular target of the adipokine vaspin (visceral adipose tissue-derived serpin; serpinA12) and its mode of action are unknown. Here, we provide the vaspin crystal structure and identify human kallikrein 7 (hK7) as a first protease target of vaspin inhibited by classical serpin mechanism with high specificity in vitro. We detect vaspin–hK7 complexes in human plasma and find co-expression of both proteins in murine pancreatic β-cells. We further demonstrate that hK7 cleaves human insulin in the A- and B-chain. Vaspin treatment of isolated pancreatic islets leads to increased insulin concentration in the media upon glucose stimulation without influencing insulin secretion. By application of vaspin and generated inactive mutants, we find the significantly improved glucose tolerance in C57BL/6NTac and db/db mice treated with recombinant vaspin fully dependent on the vaspin serpin activity and not related to vaspin-mediated changes in insulin sensitivity as determined by euglycemic-hyperinsulinemic clamp studies. Improved glucose metabolism could be mediated by increased insulin plasma concentrations 150 min after a glucose challenge in db/db mice, supporting the hypothesis that vaspin may inhibit insulin degradation by hK7 in the circulation. In conclusion, we demonstrate the inhibitory serpin nature and the first protease target of the adipose tissue-derived serpin vaspin, and our findings suggest hK7 inhibition by vaspin as an underlying physiological mechanism for its compensatory actions on obesity-induced insulin resistance.     

Immunocytochemical demonstration of calmodulin in cells secreting by exocytosis

Calmodulin is a regulator of several calcium-dependent cellular processes. It has been suggested that it plays a role in the mechanism of secretion. Employing an indirect immunoperoxidase technique at the light microscope level, this study demonstrates the presence of calmodulin in several exocytotic cells (mast cells, thyroid follicular cells, neurohypophyseal neurosecretory terminals, pancreatic beta-cells and pancreatic acinus cells) in rat and man. The positive staining reaction for calmodulin was granular and at least in the case of rat mast cells it appeared to be associated with the granule membrane.     

Dendritic reticulum cells in AIDS-related lymphadenopathy

Summary One of two cases of acquired immune deficiency syndrome-related persistent generalized lymphadenopathy revealed a profoundly altered pattern of dendritic reticulum cells as demonstrated by immunoreactive acid cysteine proteinase inhibitor. The alterations could be related to totally or partially destructed lymphoid secondary follicles.Acknowledgments. This work has been partially supported by the grant from the Sigrid Juselius Foundation, Finland.     

Chromosomal accumulation of3H-estradiol in dividing ovarial granulosa cells and ovarial squash preparations

Zusammenfassung ³H-Oestradiol wurde Mäusen injiziert und nachher autoradiographisch verfolgt, wobei Ag-Körnchen über den Chromosomen der Granulosazellen des Ovariums festgestellt werden konnten.