Na+ K+ ATPase activity in mast cells from the pleural and peritoneal cavities of the rat

ATPase activity in rat mast cells was studied, assuming that pleural and peritoneal mast cells are different populations. Mast cells were purified with Percoll. Enzymatic activity was found to be 36% higher in pleural cells that in peritoneal cells. Moreover, for both populations results show a Na+-K+ ATPase activity either low or slightly inhibited by ouabain.     

Somatostatin does not modify 3-oxymethylglucose and leucine uptake by rat enterocytes

The effects of somatostatin on 3-oxymethylglucose (3-OMG) and leucine uptake by rat enterocytes were examined. Somatostatin did not decrease the 3-OMG enterocyte uptake. When the 3-OMG active transport was inhibited by phloridzin, Somatostatin presented no significant modifications. Somatostatin showed a slight decrease in 3-OMG release through the basolateral membrane, when such a release was inhibited with theophylline. Somatostatin did not modify the intestinal leucine uptake or its inhibition by methionine.     

Thiamine limitation determines the transition from aerobic to fermentative-like metabolism in Rhizobium etli CE3

Both thiamine and biotin when added to minimal medium subcultures reversed the fermentative-like metabolism exhibited by Rhizobium etli CE3. Thiamine auxotrophs lacking thiCOGE genes were used to investigate the role of thiamine in this medium. A thiC1169∷ miniTn 5lacZ1 thiamine auxotroph subjected to the above subcultures resulted in growth arrest, reduced pyruvate-dehydrogenase activity, and a smaller amount of poly-β-hydroxybutyrate compared with the CE3 strain. Moreover, thiC and thiEb genes were overexpressed as result of thiamine limitation. The absence of classical thi genes suggests that thiamine is synthesized with low efficiency by an alternative pathway. Low levels of thiamine cause the CE3 strain to exhibit a fermentative-like metabolism.