Tuesday, October 27, 2009

Newspaper ink promotes a sun tanning-like phenotype in nude mice

Paul Kammerer, Jr. and Benjamin Coppertone
Neues Biologische Versuchsanstalt, Vienna, Austria

The Amazon rainforest is the richest region on Earth in terms of biological diversity, with an estimation of around 5 millions of different living species of plants and animals, including humans. This high biodiversity makes the region a suitable source of organic compounds with applications for mankind. Examples include the sticky additive used for chewing gum, the neuro-excitatory drugs included in commercial cigarettes, and the secret component of CokeTM, among others. To search for novel natural compounds with utility in human health, we have performed a systematic high throughput phenotypic screening of unbiased crude extracts from organic samples collected randomly all along the Amazonia, from Ecuador to the French Guiana, using as the readout phenotype variations in hairless nude mice. The Amazon Jungle was divided in 33,333 sectors of 150 square kilometres each. About 33% of the sectors were eliminated from the study due to the lack of natural material because of severe deforestation, and biological samples were systematically obtained from the remaining 22,222 sectors using an ACME (Accurately Calibrated Machines for Everything, Inc.) robotized harvester. This procedure avoided human manipulation during the collection of samples and guaranteed the obtaining of uncontaminated mixtures of natural substances. The samples were homogenized, encapsulated, and sterilized using a standard pet-dry food processor, and tested for induction of phenotype changes in nude mice after their administration in combination with the regular food. Real-time video survey of the mice cages certified that the animals really enjoyed eating the Amazonian food tablets. A diverse array of novel phenotypes was obtained in the mice, which will be described in detail elsewhere. Here, we briefly summarize the most frequent of these phenotypes, which displayed a high level of penetrance and consisted in mice showing a dotted sun tanning-like pattern.

Several rounds of fractionation and purification steps from the crude extracts from positive samples allowed the isolation of the active compound causing spotted sun tanning phenotype, and its identification as plain newspaper ink. Subsequent experiments performed with ink purified from a large pile of different newspapers, from The New York Times to Las Provincias, demonstrated that newspaper ink promotes a UV-independent sun tanning-like phenotype in mice. Importantly, nude mice treated with newspaper ink did not get sunburnt and were more resistant to skin cancer promoters, in comparison to UV-irradiated tanned mice. Furthermore, direct consumption of sterilized newspapers in the diet conferred a mild greyish but consistent dotted sun tanning appearance to the animals, which was also accompanied by skin cancer protection. Although studies addressing the effects in human populations of eating newspapers or newspaper ink have not been documented, we propose newspaper ink as a safe, cheap and reliable sun tanner for humans. In addition, considering the global economical crisis situation, the benefits of introducing used newspapers in human diet are currently under analysis. Further work will be necessary to explain the unexpected abundance of newspaper ink in natural samples from the Amazon rainforest resources.

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