In the ‘Fifth Gene Technology Report’, renowned experts provide an overview of current developments and their applications in the dynamically evolving research field of gene and biotechnologies. They examine, among other topics, genetic diagnostics, somatic gene therapy, the development of vaccines, stem cell and organoid research, green gene technology, synthetic biology, gene drives, genome editing, epigenetics and single cell analysis. In addition to reporting on the current state of affairs in this field, the authors also discuss society’s perception of gene technologies and ethical and legal issues relating to them, such as genome edit-ing, cerebral organoids and big data in personalised medicine. Moreover, the interdisciplinary task force ‘Gentechnologiebericht’ (Gene Technology Report) offers recommendations on action that could be taken in relation to the key issues. <bold>With contributions by</bold> Karla Alex, Sina Bartfeld, Meik Bittkowski, Inge Broer, Lorina Buhr, Stephan Clemens, Wolfgang Van den Daele, Hans-Georg Dederer, Tobias J. Erb, Nina Gasparoni, Heiner Fangerau, Boris Fehse, Jürgen Hampel, Louise Herde, Ferdinand Hucho, Ali Jawaid, Aida Khachatryan, Sarah Kohler, Alma Kolleck, Martin Korte, Cordula Kropp, Alfons Labisch, Markus Lehmkuhl, Melanie Leidecker-Sandmann, Annette Leßmöllmann, Isabelle M. Mansuy, Lilian Marx-Stölting, Andreas Merk, Yannick Milhahn, Fruzsina Molnár-Gábor, Stefan Mundlos, Staffan Müller-Wille, Angela Osterheider, Anja Pichl, Barbara Prainsack, Jens Reich, Marlen Reinschke, Ortwin Renn, Hans-Jörg Rheinberger, Arnold Sauter, Hannah Schickl, Silke Schicktanz, Volker Stollorz, Constanze Störk-Biber, Jochen Taupitz, Jörn Walter, Eva C. Winkler, Martin Zenke and Michael M. Zwick.

A variety of bacterial exotoxins interfere with signal transduction through type-II receptors by adenosine diphosphate-ribosylating G-proteins. Tetrodotoxin and saxitoxin act on the sodium channel by binding to its "target site 1". Toxic diterpenoids named grayanotoxins have been isolated from leaves of various Rhododendron, Kalmia, Leucothoe and Ericaceae plant species. Grayanotoxins depolarize nerve and muscle membranes by increasing sodium permeability. This effect is reversible by washing and it can be abolished by tetrodotoxin in a noncompetitive manner. Dendrotoxins are a group of single chain neurotoxins devoid of enzymatic activity and were identified as facilitating neurotransmitter release at peripheral and central synapses. The postsynaptically acting toxins are low molecular weight, basic proteins. Elctrophysiological studies confirmed that the toxin blocks neuromuscular transmission by a postjunctional action. A large number of toxins acting on nervous structures, synapses or ion-channels have been discovered during the last decades.