Protective Effects of the Postbiotic Levilactobacillus brevis BK3 against H2O2-Induced Oxidative Damage in Skin Cells.

Postbiotics have various functional effects, such as antioxidant, anti-inflammatory, and anti-obesity. Levilactobacillus brevis BK3, the subject of this study, was derived from lactic acid bacteria isolated from Kimchi, a traditional Korean fermented food. The antioxidant activity of BK3 was confirmed through the measurements of 2,2-diphenyl-1-picryl-hydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and total antioxidant capacity (TAC). The wrinkle improvement effect was validated by assessing elastase inhibitory activity and collagenase inhibitory activity. The intracellular activity was confirmed using human keratinocytes (HaCaT) and human fibroblasts (HFF-1). BK3 protects skin cells from oxidative stress induced by H2O2 and reduces intracellular reactive oxygen species (ROS) production. In addition, the expressions of the antioxidant genes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were upregulated. Meanwhile, matrix metalloproteinase-1 (MMP-1) and collagen type I alpha 1 (COL1A1), involved in collagen degradation and synthesis, were significantly regulated. These results suggest the possibility of utilizing BK3 as a functional ingredient with antioxidant and wrinkle-improving effects.

In vitro broad-spectrum antiviral activity of MIT-001, a mitochondria-targeted reactive oxygen species scavenger, against severe acute respiratory syndrome coronavirus 2 and multiple zoonotic viruses.

The COVID-19 pandemic caused by SARS-CoV-2 becomes a serious threat to global health and requires the development of effective antiviral therapies. Current therapies that target viral proteins have limited efficacy with side effects. In this study, we investigated the antiviral activity of MIT-001, a small molecule reactive oxygen species (ROS) scavenger targeting mitochondria, against SARS-CoV-2 and other zoonotic viruses in vitro. The antiviral activity of MIT-001 was quantified by RT-qPCR and plaque assay. We also evaluated the functional analysis of MIT-001 by JC-1 staining to measure mitochondrial depolarization, total RNA sequencing to investigate gene expression changes, and immunoblot to quantify protein expression levels. The results showed that MIT-001 effectively inhibited the replication of B.1.617.2 and BA.1 strains, Zika virus, Seoul virus, and Vaccinia virus. Treatment with MIT-001 restored the expression of heme oxygenase-1 (HMOX1) and NAD(P)H: quinone oxidoreductase 1 (NqO1) genes, anti-oxidant enzymes reduced by SARS-CoV-2, to normal levels. The presence of MIT-001 also alleviated mitochondrial depolarization caused by SARS-CoV-2 infection. These findings highlight the potential of MIT-001 as a broad-spectrum antiviral compound that targets for zoonotic RNA and DNA viruses, providing a promising therapeutic approach to combat viral infection.

Effects of host-associated low-temperature probiotics in olive flounder (Paralichthys olivaceus) aquaculture.

This study investigated the effects of supplementation of low-temperature probiotics isolated from the intestines of olive flounder on the growth performance, digestibility, and regulation of intestinal microbiota and the expression of genes related to growth, immunity, and apoptosis in olive flounder. Bacteria showing high growth at approximately 15-20 °C, which is the temperature of olive flounder culture, were isolated and confirmed to be Pseudomonas species through 16S rRNA gene sequence analysis. Whole-genome sequencing revealed that the strain has a 6,195,122 bp single circular chromosome and a guanine-cytosine content of 59.9%. In the feeding trial, supplementation with 1 × 108 CFU/g of the isolate strain positively modulated growth performances, digestive enzyme activity, and gut microbiota composition of olive flounder. RT-qPCR for the comparison of growth, immunity, and apoptosis-related gene expression levels showed no significant differences between the groups. Therefore, the isolated host-associated low-temperature probiotics improved the growth performance of olive flounder by causing positive changes in digestive activity and intestinal microbial composition without affecting host gene expression.