Lactic acid bacteria (LAB) are non-spore-forming, non-respiring, Gram-positive cocci or rods that produce lactic acid through carbohydrate fermentation. They are widely used in food and dairy production as probiotics, biofertilizers, and as sources of industrially valuable exopolysaccharides. Growing evidence indicates that many of these functional properties are regulated by quorum sensing (QS), a cell–cell communication mechanism that coordinates bacterial behavior in response to population density. This review summarizes current knowledge on the role of QS in regulating key physiological and functional traits of LAB, including biofilm formation, stress adaptation, metabolite production, and host interactions. Additionally, it highlights the ability of LAB-derived molecules to interfere with QS systems of pathogenic bacteria, contributing to pathogen control. Overall, this review emphasizes QS as a key regulatory mechanism underlying the technological and probiotic potential of LAB, with important implications for food, health, and biotechnological applications.

Familial Hypercholesterolemia (FH) is a common genetic disorder characterized by elevated LDL-cholesterol levels and an increased risk of premature cardiovascular disease. While pathogenic variants in LDLR, APOB, and PCSK9 are well-established causes, a substantial proportion of clinically suspected FH cases do not carry either pathogenic variants or rare variants of uncertain significance in these genes (FH/V−/USV−). This study aimed to characterize the metabolome/lipidome of genetically confirmed heterozygous FH (HeFH) patients compared to FH/V−/USV−, seeking to identify specific alterations associated with genetic status and phenotypic variability. Untargeted high-resolution mass spectrometry (UHPLC-Q-Exactive-MS)-based lipidomics and nuclear magnetic resonance-based metabolomics were performed on plasma samples of FH patients (n = 20 HeFH and n = 19 FH/V−/USV−) towards healthy controls (n = 22). PLS-DA analysis revealed group-level separation, suggesting differences in the circulating metabolome/lipidome. As expected, most of identified lipid classes were higher in both FH groups compared to normolipidemic controls. Notably, significant lipids (VIP > 1, p < 0.05) showed potential in distinguishing HeFH and FH/V−/USV− patients, particularly sphingomyelins. These data were confirmed by multivariable regression analysis controlling for age, sex, and lipid-lowering therapy as well as by ROC analysis. The evidence of a distinct lipidome signature in the HeFH subgroup may relate to the increased cardiovascular risk of HeFH patients compared to patients without pathogenic variants.

Melanin, a pigment synthesized by melanocytes, serves as the primary defense against UV-induced skin damage due to its potent antioxidant properties. There is increasing interest in natural substances capable of modulating the melanogenic pathway, particularly in hypopigmentation disorders. This study investigated the effect of methanolic extracts from the diatom Odontella aurita—authorized as a food supplement in the EU—on melanogenesis in the B16-F0 murine melanoma cell line. The research evaluated melanin content, tyrosinase activity, and the expression of melanogenesis-related genes and proteins at defined time points. Metabolomic and biochemical analyses were performed to characterize the extract’s composition. Treatment with O. aurita extract significantly increased melanin content in B16-F0 cells by 45% (p < 0.01) compared to control. Tyrosinase activity was elevated by 38% after 24 h (p < 0.01), with gene and protein expression analyses confirming upregulation of Tyrosinase (TYR) after 0.5 h, Tyrosinase Related Protein-1 (TRP1) after 1 h, and Tyrosinase Related Protein-2 (TRP2) after 8 h. The extract also enhanced the cellular antioxidant environment, as evidenced by increased levels of metabolic cofactors and pigment-precursor amino acids. O. aurita methanolic extract accelerates and sustains melanin synthesis and tyrosinase activity, distinguishing its effect from single-compound inducers. These findings support the therapeutic potential of O. aurita for pigmentary disorders and skin health. Further studies should investigate its efficacy and safety in vivo and explore its application in cosmeceutical and nutraceutical formulations.