Molecular Characterization of the Gorgonzola Cheese Mycobiota and Selection of a Putative Probiotic <i>Saccharomyces cerevisiae var. boulardii</i> for Evaluation as a Veterinary Feed Additive

Gorgonzola is an Italian “erborinato” blue cheese from cow’s milk, bearing blue-green “parsley-like” spots due to the spread of Penicillium roqueforti mycelium. Due to its pH, water activity, and high nutrient content, as well as the environmental conditions required for its maturation, Gorgonzola constitutes an optimal ecological niche supporting the growth of both yeasts and filamentous fungi. Therefore, exploring the abundant mycobiota present in this peculiar habitat is of great interest regarding the search for new probiotic strains. The present investigation aimed to characterize the Gorgonzola mycobiota using both phenotypic (macroscopic and microscopic morphological analyses) and genotypic (DNA barcoding) analyses to find possible putative probiotic strains to be used in veterinary medicine in feed supplements. Among the different isolated filamentous fungi (Mucor and Penicillium) and yeasts (Yarrowia, Debaryomyces, Saccharomyces, and Sporobolomyces), we selected a strain of Saccharomyces cerevisiae var. boulardii. We tested its adaptation to thermal stress and its stability in feed matrices. The overall results highlight that the selected strain is stable for three months and can be considered as a possible candidate for use as a probiotic in veterinary feed supplements

Norepinephrine and Serotonin Can Modulate the Behavior of the Probiotic Enterococcus faecium NCIMB10415 towards the Host: Is a Putative Surface Sensor Involved?

The human gut microbiota has co-evolved with humans by exchanging bidirectional signals. This study aims at deepening the knowledge of this crucial relationship by analyzing phenotypic and interactive responses of the probiotic Enterococcus faecium NCIMB10415 (E. faecium SF68) to the top-down signals norepinephrine (NE) and serotonin (5HT), two neuroactive molecules abundant in the gut. We treated E. faecium NCIMB10415 with 100 &micro;M NE and 50 &micro;M 5HT and tested its ability to form static biofilm (Confocal Laser Scanning Microscopy), adhere to the Caco-2/TC7 monolayer, affect the epithelial barrier function (Transepithelial Electrical Resistance) and human dendritic cells (DC) maturation, differentiation, and cytokines production. Finally, we evaluated the presence of a putative hormone sensor through in silico (whole genome sequence and protein modelling) and in vitro (Micro-Scale Thermophoresis) analyses. The hormone treatments increase biofilm formation and adhesion on Caco-2/TC7, as well as the epithelial barrier function. No differences concerning DC differentiation and maturation between stimulated and control bacteria were detected, while an enhanced TNF-&alpha; production was observed in NE-treated bacteria. Investigations on the sensor support the hypothesis that a two-component system on the bacterial surface can sense 5HT and NE. Overall, the data demonstrate that E. faecium NCIMB10415 can sense both NE and 5HT and respond accordingly