Lactiplantibacillus plantarum LRCC5314 includes a gene for serotonin biosynthesis via the tryptophan metabolic pathway

Effect of postbiotic Lactiplantibacillus plantarum LRCC5314 supplemented in powdered milk on type 2 diabetes in mice

Type 2 diabetes (T2D) is a chronic multifactorial disease characterized by a combination of insulin resistance and impaired glucose regulation. The alleviative effects of probiotics on T2D have been widely studied. However, studies on the effects of postbiotics, known as inactivated probiotics, on dairy products are limited. This study aimed to evaluate the effectiveness of postbiotic Lactiplantibacillus plantarum LRCC5314 in milk powder (MP-LRCC5314) in a stress-T2D mouse model. Compared with probiotic MP-LRCC5314, postbiotic MP-LRCC5314 significantly influenced stress-T2D-related factors. The administration of heat-killed MP-LRCC5314 reduced corticosterone levels, increased short-chain fatty acid production by modulating gut microbiota, and regulated immune response, glucose metabolism, stress-T2D-related biomarkers in the brain, gut, and adipose tissues, as well as glucose and insulin sensitivity. Additionally, heat-killed MP-LRCC5314 treatment led to a decrease in pro-inflammatory cytokine levels and an increase in anti-inflammatory cytokine levels. Overall, these findings suggest that adding postbiotic MP-LRCC5314 to milk powder could serve as a potential supplement for stress-T2D mitigation.

Fermented foods: Harnessing their potential to modulate the microbiota-gut-brain axis for mental health

Over the past two decades, whole food supplementation strategies have been leveraged to target mental health. In addition, there has been increasing attention on the ability of gut microbes, so called psychobiotics, to positively impact behaviour though the microbiota-gut-brain axis. Fermented foods offer themselves as a combined whole food microbiota modulating intervention. Indeed, they contain potentially beneficial microbes, microbial metabolites and other bioactives, which are being harnessed to target the microbiota-gut-brain axis for positive benefits. This review highlights the diverse nature of fermented foods in terms of the raw materials used and type of fermentation employed, and summarises their potential to shape composition of the gut microbiota, the gut to brain communication pathways including the immune system and, ultimately, modulate the microbiota-gut-brain axis. Throughout, we identify knowledge gaps and challenges faced in designing human studies for investigating the mental health-promoting potential of individual fermented foods or components thereof. Importantly, we also suggest solutions that can advance understanding of the therapeutic merit of fermented foods to modulate the microbiota-gut-brain axis.

Whole-Genome Sequence of Lactococcus lactis Subsp. lactis LL16 Confirms Safety, Probiotic Potential, and Reveals Functional Traits

Safety is the most important criteria of any substance or microorganism applied in the food industry. The whole-genome sequencing (WGS) of an indigenous dairy isolate LL16 confirmed it to be Lactococcus lactis subsp. lactis with genome size 2,589,406 bp, 35.4% GC content, 246 subsystems, and 1 plasmid (repUS4). The Nextera XT library preparation kit was used to generate the DNA libraries, and the sequencing was carried out on an Illumina MiSeq platform. In silico analysis of L. lactis LL16 strain revealed non-pathogenicity and the absence of genes involved in transferable antimicrobial resistances, virulence, and formation of biogenic amines. One region in the L. lactis LL16 genome was identified as type III polyketide synthases (T3PKS) to produce putative bacteriocins lactococcin B, and enterolysin A. The probiotic and functional potential of L. lactis LL16 was investigated by the presence of genes involved in adhesion and colonization of the host's intestines and tolerance to acid and bile, production of enzymes, amino acids, and B-group vitamins. Genes encoding the production of neurotransmitters serotonin and gamma-aminobutyric acid (GABA) were detected; however, L. lactis LL16 was able to produce only GABA during milk fermentation. These findings demonstrate a variety of positive features that support the use of L. lactis LL16 in the dairy sector as a functional strain with probiotic and GABA-producing properties.