A SERS and colorimetric dual-mode biosensor based on stimulus-responsive DNA/MOF-bound bimetallic nanozyme for the ultrasensitive detection of chloramphenicol in food.

A dual-mode detection platform utilizing colorimetric and Raman was developed based on the exponential amplification reaction (EXPAR) strategy and a "core-satellite" structure constructed by bimetallic nanozymes to detect chloramphenicol (CAP). Initially, DNA-gated metal-organic frameworks (MOFs) incorporating cascaded amplification were used to be nanocarriers for the colorimetric and Raman reporter molecules (3,3',5,5'-tetramethylbiphenyl; TMB). Subsequently, assembled DNA served as gatekeepers to create a stimulus-responsive DNA-gated MOF (TMB@DNA/MOF).

Multiple Pleomorphic Tetramers of Thermostable Direct Hemolysin from Grimontia hollisae in Exerting Hemolysis and Membrane Binding.

Oligomerization of protein into specific quaternary structures plays important biological functions, including regulation of gene expression, enzymes activity, and cell-cell interactions. Here, we report the determination of two crystal structures of the Grimontia hollisae (formally described as Vibrio hollisae) thermostable direct hemolysin (Gh-TDH), a pore-forming toxin. The toxin crystalized in the same space group of P222, but with two different crystal packing patterns, each revealing three consistent tetrameric oligomerization forms called Oligomer-I, -II, and -III.