Discovery of an RmlC/D fusion protein in the microalga Prymnesium parvum and its implications for NDP-ß-l-rhamnose biosynthesis in microalgae.

The 6-deoxy sugar l-rhamnose (l-Rha) is found widely in plant and microbial polysaccharides and natural products. The importance of this and related compounds in host-pathogen interactions often means that l-Rha plays an essential role in many organisms. l-Rha is most commonly biosynthesized as the activated sugar nucleotide uridine 5'-diphospho-ß-l-rhamnose (UDP-ß-l-Rha) or thymidine 5'-diphospho-ß-l-rhamnose (TDP-ß-l-Rha). Enzymes involved in the biosynthesis of these sugar nucleotides have been studied in some detail in bacteria and plants, but the activated form of l-Rha and the corresponding biosynthetic enzymes have yet to be explored in algae. Here, using sugar-nucleotide profiling in two representative algae, Euglena gracilis and the toxin-producing microalga Prymnesium parvum, we show that levels of UDP- and TDP-activated l-Rha differ significantly between these two algal species. Using bioinformatics and biochemical methods, we identified and characterized a fusion of the RmlC and RmlD proteins, two bacteria-like enzymes involved in TDP-ß-l-Rha biosynthesis, from P. parvum Using this new sequence and also others, we explored l-Rha biosynthesis among algae, finding that although most algae contain sequences orthologous to plant-like l-Rha biosynthesis machineries, instances of the RmlC-RmlD fusion protein identified here exist across the Haptophyta and Gymnodiniaceae families of microalgae. On the basis of these findings, we propose potential routes for the evolution of nucleoside diphosphate ß-l-Rha (NDP-ß-l-Rha) pathways among algae.

Novel starters for old processes: use of Saccharomyces cerevisiae strains isolated from artisanal sourdough for craft beer production at a brewery scale.

The deliberate inoculation of yeast strains isolated from food matrices such as wine or bread, could allow the transfer of novel properties to beer. In this work, the feasibility of the use of baker's yeast strains as starters for craft beer production has been evaluated at laboratory and brewery scale. Nine out of 12 Saccharomyces cerevisiae strains isolated from artisanal sourdoughs metabolized 2 % maltose, glucose and trehalose and showed growth rates and cell populations higher than those of the brewer's strain Safbrew-S33. Analysis of allelic variation at 12 microsatellite loci clustered seven baker's strains and Safbrew-S33 in the main group of bread isolates. Chemical analyses of beers produced at a brewery scale showed significant differences among the beers produced with the baker's strain S38 or Safbrew-S33, while no significant differences were observed when S38 or the brewer's strain Safbrew-F2 was used for re-fermentation. The sensory profile of beers obtained with S38 or the brewer's yeasts did not show significant differences, thus suggesting that baker's strains of S. cerevisiae could represent a reservoir of biodiversity for the selection of starter strains for craft beer production.

Monitoring the Presence of Genetically Modified Potato EH92-527-1 (BPS-25271-9) in Commercial Processed Food.

The Amflora (EH92-527-1) potato is a genetically modified (GM) potato in which only starch of the amylopectin form is produced. This has been achieved by intervening with the biosynthesis of starch in this variety of potato. The Amflora potato is solely grown for the purposes of enhancing its industrial application. Although the Amflora potato is not fit for human consumption, the presence of the potato itself or any of its derived products in the food chain cannot be excluded, it should be considerate adventitious or technically unavoidable and can be accepted in a proportion no higher than 0.9%. To achieve the goal of our work we analysed forty-five potato-derived products to evaluate transgenic potato presence by real time polymerase chain reaction, obtaining negative results. In order to verify the correct application of the law and to assure the quality for the consumer, it is necessary to continue GM monitoring to verify the adventitious presence itself in food.