Yogurt Produced by Novel Natural Starter Cultures Improves Gut Epithelial Barrier In Vitro

Abstract

Yogurt is a traditional fermented dairy product, prepared with starter cultures containing Streptococcus thermophilus and Lactobacillus bulgaricus that has gained widespread consumer acceptance as a healthy food. It is widely accepted that yogurt cultures have been recognized as probiotics, due to their beneficial effects on human health. In this study, we have characterized technological and health-promoting properties of autochthonous strains S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 isolated from artisanal sour milk and yogurt, respectively, in order to be used as functional yogurt starter cultures. Both BGKMJ1-36 and BGVLJ1-21 strains have the ability to form curd after five hours at 42 °C, hydrolyze αs1-, β-, and κ- casein, and to show antimicrobial activity toward Listeria monocytogenes. The strain BGKMJ1-36 produces exopolysaccharides important for rheological properties of the yogurt. The colonies of BGKMJ1-36 and BGVLJ1-21 strains that successfully survived transit of the yogurt through simulated gastrointestinal tract conditions have been tested for adhesion to intestinal epithelial Caco-2 cells. The results reveal that both strains adhere to Caco-2 cells and significantly upregulate the expression of autophagy-, tight junction proteins-, and anti-microbial peptides-related genes. Hence, both strains may be interesting for use as a novel functional starter culture for production of added-value yogurt with health-promoting properties.

Exopolysaccharides from Bifidobacterium animalis Ameliorate Escherichia coli-Induced IPEC-J2 Cell Damage via Inhibiting Apoptosis and Restoring Autophagy

“…Consistent with our study, the protein levels of Beclin 1, ATG5, and LC3B-II were decreased during EPEC infection, whereas EPS upregulated these protein expressions, suggesting that EPS promoted autophagosome synthesis. Notably, the EPS-producing strain Streptococcus thermophilus BGKMJ1-36 was proved that it can trigger autophagy indicated as significantly upregulating the expressions of autophagy-related genes including Beclin 1, ATG5, and LC3B-II [38]. A previous study showed that Lactobacillus johnsonii L531 increased ATG5 protein expression for maintaining the autophagy process to accelerate Salmonella infantis clearance in IPEC-J2 cells [27].…”

Traditional Bulgarian Dairy Products: Ethnic Foods with Health Benefits

“…Bulgarian yoghurt and white brined cheese are rich sources of strains producing exopolysaccharides (EPS), macromolecular compounds known for their anticancer and immunomodulatory activity, as well as the ability to maintain the intestinal barrier by regulating the functions of the gut microbiome [87,88].…”

Probiotic-mediated p38 MAPK immune signaling prolongs the survival of Caenorhabditis elegans exposed to pathogenic bacteria

“…Probiotic lactobacilli and their secreted molecules have a well-described role in the reinforcement of the gut intestinal barrier by increasing expression of tight junction proteins 40 , 41 . As BGMK2-41-mediated C. elegans resistance to both tested pathogens was uncoupled from their CFUs number in the gut, we propose that upregulated expression of clc-1 consequently strengthened the tight junctions, which may be responsible for the observed longevity extension of infected worms.…”