The Synergy™ HT - A Unique Multi-Detection Microplate Reader for HTS and Drug Discovery

A metagenomic approach to unveil the association between fecal gut microbiota and short-chain fatty acids in diarrhea caused by diarrheagenic Escherichia coli in children

Diarrheagenic Escherichia coli (DEC) is the main cause of diarrhea in children under five years old. The virulence of DEC is tightly regulated by environmental signals influenced by the gut microbiota and its metabolites. Short-chain fatty acids (SCFAs) are the main metabolic product of anaerobic fermentation in the gut, but their role in DEC diarrhea has not yet been established. In this study, we determine the levels of acetate, propionate, and butyrate in stool samples from children with diarrhea caused by DEC, and we identify bacteria from the fecal gut microbiota associated with the production of SCFAs. The microbiota and SCFAs levels in stool samples obtained from 40 children with diarrhea and 43 healthy children were determined by 16S rRNA gene sequencing and HPLC, respectively. Additionally, shotgun metagenomics was used to identify metagenome-assembled genomes (MAGs) in a subgroup of samples. The results showed significantly higher levels of all SCFAs tested in diarrheal samples than in healthy controls. The abundance of Streptococcus sp., Limosilactobacillus, Blautia, Escherichia, Bacteroides, Megamonas, and Roseburia was higher in the DEC group than in healthy individuals. Functional analysis of bacteria and their main metabolic pathways made it possible to identify species MAGs that could be responsible for the detected SCFAs levels in DEC-positive diarrhea. In conclusion, based on our results and published data, we suggest that SCFAs may be important in the crosstalk between the microbiota and DEC pathogens in the gut.

Simultaneous immunofluorescent imaging of gliadins, low molecular weight glutenins, and high molecular weight glutenins in wheat flour dough with antibody-quantum dot complexes

Gluten proteins and their impact in the quality of wheat based food products is well known. In order visualize the 'in situ' distribution of low molecular weight glutenins, high molecular weight glutenins, and gliadins simultaneously in wheat doughs we needed to overcome and eliminate dough auto-fluorescence, and to develop a reliable immunostaining procedure for their simultaneous detection in wheat doughs. We are studying different auto-fluorescence quenchers used in biological fluorescent imaging and their effect on dough auto-fluorescence removal, and the effect of different fixative mediums on the adhesion of wheat flours doughs onto microscope slides. We found that the best method to remove dough auto-fluorescence is removing it as background in the microscope detection system. We also found methanol to be the best fixative medium for dough samples. In this research, we are showing the first 'in situ' localization of these gluten subunits simultaneously in wheat flour dough.