The acute toxicity of tri-n-butyltin taurocholate

The acute toxicity for tri-n-butyltin taurocholate (TBT-TA), a newly synthesized organotin steroid, was determined using Long Evans rats. The organotin compound was suspended in corn oil and administered by gavage using standard techniques. The TBT-TA exhibited a taurocholic acid toxicity at 24 h and a tributyltin toxicity at three days. The LD₅₀ values were 611 and 384 mg kg^?1 respectively. The dead rats exhibited distended stomachs, enlarged cecums, and lesions in the gastrointestinal tract. The toxicity is similar to that observed with other trialkyltin compounds.     

Frontiers and opportunities in chemoenzymatic synthesis

Natural product biosynthetic pathways have evolved enzymes with myriad activities that represent an expansive array of chemical transformations for constructing secondary metabolites. Recently, harnessing the biosynthetic potential of these enzymes through chemoenzymatic synthesis has provided a powerful tool that often rivals the most sophisticated methodologies in modern synthetic chemistry and provides new opportunities for accessing chemical diversity. Herein, we describe our research efforts with enzymes from a broad collection of biosynthetic systems, highlighting recent progress in this exciting field.     

RHEOLOGICAL PROPERTIES AND APPLICATIONS OF MESQUITE TREE (PROSOPIS JULIFLORA) GUM. 3. THE INFLUENCE OF MESQUITE GUM OH THE INTERFACIAL TENSION BETWEEN OIL AND WATER

The influence of mesquite gum on the interfacial tension between liquid paraffin and distilled water has been studied as a function of gum concentration, pH, and added NaCl or CaCl₂. The time dependence of the reduction in interfacial tension was influenced by all three variables. Diffusion to the oil-water interface was the dominant factor in the initial decrease of interfacial tension when low mesquite gum concentrations were used. Reconformation of molecules adsorbed at the oil-water interface controlled the reduction in interfacial tension at longer times when using more concentrated gum solutions.