Last month Schulz et al. from the Technical University at Munich published a new study in Nature showing that a high-fat diet dysregulates the host microbiome and promotes carcinogenesis in mice. Introduction of a high-fat diet to mice bearing an oncogenic form of the small GTPase, Ras, (K-rasG12Dint) was found to promote tumour progression in the small intestine of this genetically susceptible strain. Interestingly, this was found to be independent of obesity. The high fat diet in combination with the mutation in the small G-protein resulted in dysbiosis of gut flora, and the authors propose a mechanism involving a decrease in Paneth-cell-mediated antimicrobial host defense and decreased dendritic cell recruitment and function in gut-associated lymphoid tissues. Next the investigators crossed mice bearing the K-Ras mutation with MyD88 knockout mice. MyD88 is an inflammatory signalling adaptor protein and its function includes activation of signalling in response to detection of microbial products by Toll-like receptors. Blockade of inflammatory signals as a result of MyD88 deficiency was found to prevent the combined effects of the K-Ras mutation and high fat diet on tumourigenesis, consistent with dysbiosis of microbiota being a causal factor. Interestingly, the disease was transmissible: transfer of faeces from K-Ras mutant mice on a high fat diet to K-Ras mutant mice receiving a normal diet was sufficient to promote tumourigenesis. Antibiotic treatment of the mice was also found to reverse the effects of the high-fat diet. So, unfortunately, we have yet another worry before we tuck into our next cod and chips!
The good news is that if you are involved in microbiome research we offer kits with tried and tested performance for purification of DNA and RNA from faecal samples, soil, and water. The kits from MO BIO have excellent performance in purification of high purity DNA/RNA samples with PCR-inhibitor removal and are compatible with high throughput sequencing, qRT-PCR, and other techniques.
The MO BIO PowerFecal® and PowerSoil® DNA Isolation Kits have been used in the Human Microbiome Project and are great to get you going. If you need to scale up your number of isolations, we offer the PowerSoil® kit in a 96-well silica spin plate and magnetic bead-based format. These kits are functionally equivalent to the PowerFecal® kit (both can be used on stool with equal success) so we recommend that you use the PowerSoil® kit if you plan to scale up in the future.
For RNA we recommend the PowerMicrobiome™ RNA kit. If you omit the on-column DNase-step you can use it to purify RNA and DNA at the same time. We also offer a PowerMag® Microbiome RNA/DNA kit specifically for high throughput purification of RNA and DNA using magnetic bead technology.
You can use the URL below for the link…
Schulz MD, Atay C, Heringer J, Romrig FK, Schwitalla S, Aydin B, Ziegler PK, Varga J, Reindl W, Pommerenke C, Salinas-Riester G, Böck A, Alpert C, Blaut M, Polson SC, Brandl L, Kirchner T, Greten FR, Polson SW, Arkan MC.
Nature. 2014 Aug 31. doi: 10.1038/nature13398. [Epub ahead of print]