Lichtgedanken 02

Editorial 56 Trees of life rooted in Jena Science historians and biology didacticians Prof. Dr Uwe Hoßfeld and Dr Georgy S. Levit recall the birth of phylogenetic trees 150 years ago in the renowned special interest magazine »Nature« How do you visualize diversity? Biolo- gists in the 19th century found themsel- ves facing this question when they be- came aware not only of the diversity of plant and animal species but also that they are interconnected. The answer was supplied by Ernst Haeckel: Starting from Darwin’s theory of evolution 150 years ago, the famous scholar created the first Darwinian phylogenetic tree of organisms and published it in his paper »General Morphology of Organisms«. In the special interest magazine »Natu- re«, the science historians and biology didacticians Prof. Dr Uwe Hoßfeld and Dr Georgy S. Levit recalled the birth of the »Tree of Life« as it is usually referred to (DOI: 10.1038/540038a). Haeckel was influenced not only by Darwin when inventing trees of life. A colleague and friend in Jena from the field of linguis- tics also inspired him. »The linguist August Schleicher had already created the first tree of life in 1863 in order to illustrate the development of Indo-Ger- manic languages,« says Hoßfeld. »Ernst Haeckel then took up this method of vi- sualization.« sh Hard shell — healthy kernel Nutritionists have good news for anyone who enjoys eating nuts. Nuts, as the results of current studies show, can reduce the growth of cancer cells in the gut Roasted and salted, ground into biscuits or freshly cracked from the shell – nuts are healthy. »We have known for a long time that nuts are full of substances that are good for the cardiovascular system and that protect against obesity or dia- betes,« says Dr Wiebke Schlörmann. The effect they have in protecting against bowel cancer has also already been indicated in numerous studies, the nutritionists continue. »What we did not yet know in detail, was the ba- sis for the protective effect of nuts.« Dr Schlörmann and her colleagues from the Department of Nutritional Toxicolo- gy are now able to give concrete ans- wers to this question. In the magazi- ne »Molecular Carcinogenesis«, they presented results which illuminate the molecular mechanisms of this protec- tive effect (DOI: 10.1002/mc.22606). According to this study, the health- promoting effect of nuts is based among other things on the fact that the body’s own defence for detoxifying reactive oxygen species is activated. Such sub- stances which are created, for example, by ultraviolet radiation or various che- micals, can cause damage to cells that can trigger cancer. »But the body pos- sesses a whole series of protective me- chanisms which render reactive oxygen species harmless,« explains Dr Schlör- mann. These mechanisms are mobi- lized by nuts and their ingredients. The researchers examined the effect of macadamia nuts, hazelnuts, walnuts as well as almonds and pistachios. To do so, the nuts were artificially dige- sted, and the products of the digestive process were subsequently examined for their effect on cell lines. US Above: Walnuts and other nuts offer protection from cancer. Below: Part of a facsimile of the »Human Family Tree« by Ernst Haeckel.