Metabolic deactivation of the herbicide thiazopyr by animal liver esterases.

1. Thiazopyr was hydrolysed in vitro to its corresponding acid by rabbit and porcine liver esterases. 2. A wide range of thiazopyr esterase activity was observed in extracts from liver acetone powders from 15 animal species with bovine, rabbit and pigeon showing the highest activities. 3. Using soybean tissue culture cells and Arabidopsis seedlings, the acidic metabolite was shown to possess < 1% of the herbicidal activity of thiazopyr. 4. We propose that biotransformation of thiazopyr to the acid is a critical pathway of metabolism in animals and plants.

Molecular cloning of a murine fibronectin receptor and its expression during inflammation. Expression of VLA-5 is increased in activated peritoneal macrophages in a manner discordant from major histocompatibility complex class II.

Human fibronectin receptor (VLA-5) alpha and beta chain probes were used to identify their mouse homologues in a thioglycollate-elicited peritoneal exudate cell cDNA library. Sequence analysis of both alpha and beta chain-related murine clones revealed approximately 90% homology to their human counterparts by both nucleotide and derived amino acid sequence comparisons. Detectable alpha chain transcripts were seen predominantly in total RNA of peritoneal macrophages. beta chain expression, however, was detected at higher levels in lung, heart, brain, and kidney, suggesting the presence of a large murine VLA family similar to the human family. Analysis of levels of expression comparing resting peritoneal macrophages with macrophages elicited using inflammatory stimuli indicated that alpha chain message and surface VLA-5 expression were significantly increased using thioglycollate or Listeria monocytogenes as stimuli to elicit cells. Interestingly, beta chain message was unaffected by these inflammatory stimuli, suggesting that VLA-5 expression is regulated by VLA-5 alpha chain message levels. These results indicate that macrophage VLA-5 expression can be modulated in vivo and may provide an important mechanism by which macrophages are recruited to or adhere to fibronectin in inflammatory foci.