No abstract

We report a genetically encoded, residue-selective protein photo-crosslinker enabling covalently crosslinking protein-protein interactions with proximal lysine upon UV light activation in vitro and in living cells. Combining the advantages of temporal control and residue selectivity, a new crosslinking approach was developed, producing predictable crosslinking site and crosslinked peptides, and capturing elusive enzyme-substrate interaction with directly interacting lysine. This strategy represents higher spatiotemporal resolution and reliability for investigating protein-protein interactions, thus, better understanding of biological processes and pathophysiology.

No abstract

Lactobacillus plantarum MA2 was isolated from traditional Chinese Tibet kefir grains, which possess several excellent properties and functions. We previously demonstrated the antioxidant activities of this bacterium in vitro. However, the maintenance and survival of L. plantarum MA2 inside the murine intestinal tract, where it exerts its probiotic properties, and whether its effects are elicited directly on the host remain unknown. Therefore, this study investigated the mechanisms of L. plantarum MA2 in aging mice following D-galactose administration. The levels of malondialdehyde decreased significantly in the L. plantarum MA2 groups after oral ingestion compared to the D-galactose model group, and total antioxidant capacity and glutathione peroxidase and superoxide dismutase activities increased significantly in the serum and liver. We combined fluorescein isothiocyanate labeling and green fluorescent protein expression to dynamically monitor the colonization and distribution of L. plantarum MA2 in the murine intestinal tract. The results indicated that L. plantarum MA2 was detected in the ileum, colon, and feces after single and continuous oral administration at day 21 and was maintained at 10(4)-10(5) CFU/g. These results suggest that L. plantarum MA2 colonizes and survives in the murine intestinal tract to exert its antioxidative effects.