Towards the Human Colorectal Cancer Microbiome

Multiple factors drive the progression from healthy mucosa towards sporadic colorectal carcinomas and accumulating evidence associates intestinal bacteria with disease initiation and progression. Therefore, the aim of this study was to provide a first high-resolution map of colonic dysbiosis that is associated with human colorectal cancer (CRC). To this purpose, the microbiomes colonizing colon tumor tissue and adjacent non-malignant mucosa were compared by deep rRNA sequencing. The results revealed striking differences in microbial colonization patterns between these two sites. Although inter-individual colonization in CRC patients was variable, tumors consistently formed a niche for Coriobacteria and other proposed probiotic bacterial species, while potentially pathogenic Enterobacteria were underrepresented in tumor tissue. As the intestinal microbiota is generally stable during adult life, these findings suggest that CRC-associated physiological and metabolic changes recruit tumor-foraging commensal-like bacteria. These microbes thus have an apparent competitive advantage in the tumor microenvironment and thereby seem to replace pathogenic bacteria that may be implicated in CRC etiology. This first glimpse of the CRC microbiome provides an important step towards full understanding of the dynamic interplay between intestinal microbial ecology and sporadic CRC, which may provide important leads towards novel microbiome-related diagnostic tools and therapeutic interventions

Energy consumption in the food chain - Comparing alternative options in food production and consumption

Energy consumption in the various stages of the food chain, provides a reasonable indicator for the environmental impact in the production of food. This paper provides specific information on the energy requirement for the main alternatives in each production stage, which should allow the identification of improvement options. One observation is that there seems to be a remarkable relationship between energy requirement throughout the production chain and market value. Products with a high added (emotional) value, e.g. wine, season fruits, and coffee, deviate from the abovementioned relationship. However, that deviation may be overcome when the emotional value is included in the functional unit of the food product. It is concluded that there seems to be no systematic environmental benefit for home-made over industrially produced food. For all food categories, there is a wide variety in energy requirement due to three major factors, viz. season of consumption (fresh versus import and glasshouse production), scale of preparation (home-made and industrial scare) and consumer preference (meat versus vegetable food)

Active site and catalytic mechanism of phospholipase A2

The esterolytic enzyme phospholipase A2 specifically splits the 2-acyl linkage of phosphoglycerides in a calcium-dependent reaction. In the pancreas the enzyme occurs as a zymogen which is activated on secretion into the duodenal tract by the removal of seven amino acid residues from the N terminus by trypsin. Having refined our X-ray analysis of the crystal structure of bovine pancreatic phospholipase A2 from 2.4 Å to 1.7 Å resolution, we now describe how the structure of the molecule may account for the specificity of the enzyme and for the sudden and dramatic change in activity when the substrate concentration passes the critical micelle concentration.