Emerging evidence suggests that probiotics are beneficial in non-alcoholic fatty liver disease (NAFLD). This study aimed to explore the effects of two Lactobacillus plantarum strains, ATG-K2 and ATG-K6 (isolated from Korean fermented cabbage), in a rat model of high fat/high fructose (HF/HF) diet-induced NAFLD. Rats with NAFLD were randomized into four groups (HF/HF diet control, (HC); HF/HF diet with silymarin, (PC); HF/HF diet with ATG-K2, (K2); and HF/HF diet with ATG-K6, (K6)) with healthy rats on a normal diet serving as the negative control. After treatment, histopathological and biochemical analyses of the blood and liver tissue were conducted. In addition, fecal microbiota was analyzed using the MiSeq platform. Compared with HC rats, K2 and K6 rats experienced significantly lower body weight gain, displayed decreased hepatic lipid accumulation, had lower serum levels of aspartate aminotransferase and alanine aminotransferase, and showed increased antioxidant enzyme activities. Moreover, de novo lipogenesis-related genes were downregulated following K2 and K6 administration. The fecal microbiota of K2 and K6 rats contained a higher proportion of Bacteriodetes and a lower proportion of Fimicutes than that of HC rats. Taken together, our results suggest that L. plantarum strains ATG-K2 and ATG-K6 are potential therapeutic agents for NAFLD.

Many Bacillus species are among the plant growth-promoting rhizobacteria (PGPR) that promote the growth of many different plant species. This study aimed to investigate the effects of Bacillus thuringiensis KNU-07 on the growth of pepper plants and the soil microbiota. We also designed primers specific for the strain KNU-07 to monitor the population in pepper-cultivated soil. Accordingly, a strain-specific primer pair was designed using a database constructed from 16,160 complete bacterial genomes. We employed quantitative PCR (qPCR) to track the abundance of the strain KNU-07 introduced into pepper-cultivated soil using the strain-specific primers. Our study revealed that the strain was found to possess plant growth-promoting (PGP) activities, and it promoted the growth of pepper plants. The soil bacterial community structure due to the application of the PGPR strain was significantly changed after six weeks post-inoculation. In addition, based on qPCR analysis, the population of the introduced strain declined over time. In this study, application of a PGPR strain increased the growth of pepper plants and changed the soil bacterial community structure. The successful results of monitoring of a bacterial strain’s population using a single strain-specific primer pair can provide important information about the quantification of bio-inoculants under non-sterile soil conditions.

Obesity is a major health problem. Compelling evidence supports the beneficial effects of probiotics on obesity. However, the anti-obesity effect of probiotics remains unknown. In this study, we investigated the anti-obesity effects and potential mechanisms of Lactiplantibacillus plantarum ATG-K2 using 3T3-L1 adipocytes and high-fat diet (HFD)-induced obese mice. 3T3-L1 cells were incubated to determine the effect of lipid accumulation with lysate of L. plantarum ATG-K2. Mice were fed a normal fat diet or HFD with L. plantarum ATG-K2 and Orlistat for 8 weeks. L. plantarum ATG-K2 inhibited lipid accumulation in 3T3-L1 adipocytes, and reduced body weight gain, WAT weight, and adipocyte size in HFD-induced obese mice, concurrently with the downregulation of PPARγ, SREBP1c, and FAS and upregulation of PPARα, CTP1, UCP1, Prdm16, and ND5. Moreover, L. plantarum ATG-K2 decreased TG, T-CHO, leptin, and TNF-α levels in the serum, with corresponding gene expression levels in the intestine. L. plantarum ATG-K2 modulated the gut microbiome by increasing the abundance of the Lactobacillaceae family, which increased SCFA levels and branched SCFAs in the feces. L. plantarum ATG-K2 exhibited an anti-obesity effect and anti-hyperlipidemic effect in 3T3-L1 adipocytes and HFD-induced obese mice by alleviating the inflammatory response and regulating lipid metabolism, which may be influenced by modulation of the gut microbiome and its metabolites. Therefore, L. plantarum ATG-K2 can be a preventive and therapeutic agent for obesity.

Panax ginseng is a well-known medicinal plant that achieves strong resistance against plant pathogens while growing in the wild. Due to the high market demand for ginseng as a health food source, ginseng cultivation is prevalent in South Korea. However, continuous monocropping creates problems like irregular growth or vulnerability to crop diseases. Quorum sensing (QS) deals with the intracellular communication of bacteria and plays a role in dynamic changes in the soil microbiome. Here, we investigated how acyl-homoserine lactone (AHL) signaling molecules in QS (C8, C10, and C12) improve plant growth and induce shifts in the soil microbiome. To assess the effects, we recorded root and shoot growth of ginseng seedlings and checked the changes in the soil microbiome during different time points (0, 2, 4, and 8) after 8 weeks of growth. We observed that soils treated with N-decanoyl-_L-homoserine lactone (C10) showed the most pronounced effects. Very striking was that C10 had the lowest alpha diversity. Using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2), we observed a high number of QS-related functional genes, with the highest count occurring in the untreated planted soil (W). Together with the known direct and beneficial effects of AHLs on plant development, AHLs treated mono-cropped soil showed trends in the microbiome community.

Air pollutants can cause respiratory diseases, highlighting the need for effective preventive and therapeutic strategies. We investigated the protective effects of heat-killed Lacticaseibacillus paracasei ATG-E1 against particulate matter plus diesel exhaust particle (PM₁₀D)-induced airway inflammation. BALB/c mice were intranasally injected with PM₁₀D and treated with heat-killed L. paracasei ATG-E1 via oral gavage for 5 days. In the bronchoalveolar lavage fluid (BALF) and lungs, inflammatory mediators, immune cell subtypes, and histological changes were analyzed, while gut microbiota composition was analyzed in the cecum. Heat-killed L. paracasei ATG-E1 suppressed the infiltration of immune cells, including neutrophils, T cells, and B cells. Furthermore, it decreased various inflammatory mediators, such as C-X-C Motif chemokine ligand (CXCL)-1, macrophage inflammatory protein (MIP)-2, interleukin (IL)-1α, and tumor necrosis factor (TNF)-α, in the BALF and lung tissue, as well as serum symmetric dimethylarginine (SDMA) levels in the PM₁₀D-induced airway inflammation model. Heat-killed L. paracasei ATG-E1 also exhibited a protective effect against lung damage induced by PM₁₀D. Furthermore, heat-killed L. paracasei ATG-E1 treatment shifted the gut microbiota composition, increasing several bacterial genera. The data demonstrate that heat-killed L. paracasei ATG-E1 acts as a protective agent against air pollutant-induced lung injury, suggesting its potential as a candidate adjunctive strategy for prevention.