We previously have demonstrated that insulin and insulin-like growth factor-I (IGF-I) down-regulate growth hormone (GH) binding in osteoblasts by reducing the number of surface GH receptors (GHRs). The present study was undertaken to investigate the mechanism of GHR down-regulation. Treatment with 5 nM insulin or IGF-I for 18 hr significantly decreased surface GH binding to 26.4 +/- 2.9% and 23...

The role of Toll-like receptor 4 (TLR4)/nuclear factor-kappa-B (NF-κB) in intestinal mucosal barrier damage and bacterial translocation under hypoxic exposure is unclear. Here, we investigated their role using an acute hypobaric hypoxia model. Adult Sprague-Dawley rats were divided into control (C), hypoxia (H), hypoxia+NF-κB inhibitor pyrrolidinedithiocarbamic acid (PDTC) (100 mg. kg) (HP), hy...

one of the most important methods to investigate heavy metals as pollutants is more likely to use bio-monitors which can be applied as an appropriate index to express the quality of environment. in current study, in order to investigate the effects of dominant plants in the desired region and role of aquatic macrophytes in monitoring such elements as zinc (zn), lead (pb), copper (cu) and cadmiu...

The delivery of the diphtheria toxin catalytic domain (DTA) from acidified endosomes into the cytoplasm of eukaryotic cells requires protein-protein interactions between the toxin and a cytosolic translocation factor (CTF) complex. A conserved peptide motif, T1, within the DT transmembrane helix 1 mediates these interactions. Because the T1 motif is also present in the N-terminal segments of le...

BACKGROUND During the translation of mRNA into polypeptide, elongation factor G (EF-G) catalyzes the translocation of peptidyl-tRNA from the A site to the P site of the ribosome. According to the 'classical' model, EF-G in the GTP-bound form promotes translocation, while hydrolysis of the bound GTP promotes dissociation of the factor from the post-translocation ribosome. According to a more rec...

Patients with obstructive jaundice are prone to septic complications after biliary tract operations. Restoring bile flow to the intestine may help to decrease the complication rate. The present study is aimed at evaluating the effect of biliary decompression on bacterial translocation in jaundiced rats. Sixty-six male Sprague-Dawley rats were randomly allocated to six groups subjected to common...

We review transient kinetic methods developed to study the mechanism of translocation of nucleic acid motor proteins. One useful stopped-flow fluorescence method monitors arrival of the translocase at the end of a fluorescently labeled nucleic acid. When conducted under single-round conditions the time courses can be analyzed quantitatively using n-step sequential models to determine the kineti...