2019
Prof. Dr. Sylvia Kaiser, Adjunct Professor, Department of Behavioural Biology, University of Münster
How to assess animal welfare?
15.01.2019 19ct
Good scientific practice in biomedical research includes assuring good welfare of experimental animals. Welfare can vary on a continuum from very good to very poor. The crucial question is: What are suitable methods to assess animal welfare objectively? In the last decades animal welfare research succeeded to establish reliable methods to diagnose welfare of animals living under human made housing conditions. In this talk, physiological and ethological indicators for animal welfare will be discussed on the basis of research examples: the main focus will be on stress hormones, spontaneous behaviour as well as preference tests. Furthermore, the assessment of emotions will be highlighted. Taken together, this talk aims to discuss an animal friendly housing and handling of experimental animals.
2018
Prof. Dr. Sara A. Wickström, Helsinki Institute of Life Science, University of Helsinki, Finland and Max Planck Institute for Biology of Ageing, Cologne, Germany
Regulation of stem cell fate by niche-derived signals and forces
29.11.2018 19ct
Our research aims to uncover how complex but stereotyped tissues are formed, maintained and regenerated through local growth, differentiation and remodeling. To decipher this fundamental question we need to understand how single cell behaviors are coordinated on the population level and how population-level dynamics is coupled to tissue architecture. Uncovering these regulatory principles will further facilitate development of stem cell (SC) therapies and effective treatments against cancers. As a self-renewing organ maintained by distinct stem cell populations, the epidermis represents an outstanding, clinically highly relevant research paradigm to address these questions. We apply mouse genetics and molecular cell biology, combined with state-of-the art biological imaging, biophysics, biochemistry and theoretical approaches to study stem regulation and tissue homeostasis/aging in this system. In my presentation I will discuss our recent research on stem cell-niche interactions in cell fate decisions and plasticity, and the role of mechanical forces in these processes.
Prof. Dr. Christiane Nüsslein-Volhard, Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
The stripes of Zebrafish: Development and evolution of biological aesthetics
08.11.2019 19ct
Colour patterns are prominent features of most animals; they play an important role in social communication such as kin recognition, sexual atrraction, camouflage and aposematism.Colour patterns are highly variable and evolve rapidly leading to large diversities between species even within a single genus. Despite their importance as targets for both, natural and sexual selection, little is known about the development and evolution of colour patterns in vertebrates.The zebrafish (Danio rerio) displays a conspicuous pattern of alternating blue and golden stripes on the body and on the anal- and tailfins composed of pigment cells– melanophores, iridophores and xanthophores– distributed in three superimposed monolayers under the skin. The pigment cells originate from neural crest-derived multipotent stem cells associated with the dorsal root ganglia of the peripheral nervous system and share a lineage with neurons and glia of the peripheral nervous system. The proliferation of pigment cells is regulated by competitive interactions among cells of the same type. This mode of colouring the skin is probably common to fish, whereas different patterns emerge by species specific cell interactions among the different pigment cell types. These interactions are mediated by membrane-bound channels involved in direct cell contact between the pigment cells, as well as unknown cues provided by the tissue environment. The colour patterns in closely related Danio species are amazingly different; their variation offers a great opportunity to investigate the genetic and developmental basis of colour pattern evolution in vertebrates. Exciting technical developments of the recent years, especially the novel possibilities of genome editing with the CRISPR/Cas9 system, allow to expand from model organisms into other species and directly test the function of genes by targeted knock outs and allele replacements. Thus, models and hypotheses about pigment pattern formation derived from zebrafish can now be tested in other Danio species. These studies will lay the foundation to understand not only the genetic basis of colour pattern variation between Danio species, but also the evolution of colour patterns in other vertebrates.
Prof. Dr. Ampero Acker-Palmer, Molecular and Cellular Neurobiology, Goethe-University Frankfurt The Neurovascular link
17.04.2018 19ct
The Neurovascular link: The development of the nervous and the vascular systems exhibit extensive similarities, both on the anatomical and the molecular level. Blood vessels and nerves are structurally similar and often aligned, following parallel routes. The brain is the most vascularized tissue in our body. In the past, we have discovered that the same molecular mechanisms are used to orchestrate the development of the nervous and the vascular system. It is now believed that blood vessels in the brain exert instructive functions that go beyond supplying nutrients and oxygen, for example supplying ligands that directly influence neuronal behavior by activating corresponding receptors and signaling pathways in neuronal cells. We are interested in elucidating the molecular pathways involved in the crosstalk between vessels and nerves and how this crosstalk signaling is integrated among the different cellular players (neurons, endothelial cells, astrocytes) at the neurovascular interface during CNS development and during adult functions such as blood brain barrier maintenance and synaptic plasticity.
Prof. Dr. Detlef Bartsch, Head of the Department „Gene Technology“at the Federal Office of Consumption Protection and Food Safety (BVL) in Berlin Genome editing- where precaution meets Innovation
30.01.2018 19ct
Genome editing – where precaution meets innovation.
One important question of today’s society is whether all genome edited organisms would be classified as genetically modified organism (GMO). Past experiences with GMO demonstrated that authorized GMO are safe for both human/animal health and the environment since no technique-specific risk has been identified. Hitting the brakes for a complete ban of genome editing is not a realistic option, and we need a concerted action on how modern biotechnologies should be applied in both a cautious and innovative way. It is definitely not only a technological but also a social and ethical debate. Taking no action by avoiding any change could increase the risk of food insecurity and socio-economic disasters. Our environment is constantly changing by the increasing number of humans followed by their impact on resources. Our common future can only be guaranteed if we intelligently apply all useful technologies for both, a sustainable and a social secure use of our common water, air, soil, and biological entities.
2017
Prof. Dr. Stefan Raunser, Max-Planck-Institut für molekulare Physiologie
The power of cryo-EM to elucidate biological mechanisms
16.10.2019 19ct
Muscular movement plays an essential role not only in our lives. Muscle contraction is initiated by the release of calcium from the sarcoplasmic reticulum into the cytoplasm of myocytes through ryanodine receptors. Calcium binds to troponin, which releases tropomyosin from its blocking position allowing myosin filaments to move along actin filaments resulting in the contraction of the muscle. Upon infection with bacterial pathogens, F-actin, which is not only the major component of muscles but also the cytoskeleton, is attacked by Tc toxin complexes. Tripartite Tc toxin complexes perforate the host membrane by forming channels that translocate toxic enzymes into the host, including humans.The underlying mechanism of Tc toxin action and the function and regulation of muscle contraction are complex but poorly understood. In my talk I will present our recent published and unpublished findings revealing important molecular details of both processes.