Functional role of P-selectin glycoprotein ligand 1/P-selectin interaction in the generation of tolerogenic dendritic cells

Dendritic cells (DCs) have a key role in both the generation of the immune response and the induction of tolerance to self-Ags. In this work, the possible role of P-selectin glycoprotein ligand 1 (PSGL-1) on the tolerogenic activity of human DCs was explored. We found that the engagement of PSGL-1 by P-selectin on DCs induced the expression of c-Fos, IDO, IL-10, and TGF-beta genes. Remarkably, stimulation of DCs through PSGL-1 with P-selectin enhanced their capability to generate CD4(+)CD25(+)Foxp3(+) regulatory T cells, which expressed high levels of TGF-beta1 mRNA, synthesized IL-10, and suppressed the proliferation of autologous CD4(+)CD25(-) T cells. Accordingly, we found that DCs from PSGL-1(-/-) mice expressed higher levels of MHC class II molecules, and exhibited an enhanced immunogenicity compared with wild-type mice. In addition, the percentage of CD4(+)CD25(+)Foxp3(+) regulatory T cells in the thymus of PSGL-1-deficient animals was significantly reduced. Our data reveal an unexpected role of PSGL-1 on the tolerogenic function of DCs, and the regulation of the immune response.     

Identification and characterization of a novel activated RhoB binding protein containing a PDZ domain whose expression is specifically modulated in thyroid cells by cAMP.

In a search for genes regulated in response to cAMP we have identified a new protein, p76RBE, whose mRNA and protein expression is enhanced in thyrocytes following thyrotropin stimulation of the cAMP transduction cascade. This protein presents important similarities with Rhophilin and contains different protein-protein interaction motifs. The presence of HR1 and PDZ motifs as well as a potential PDZ binding domain motif suggests that p76RBE could be implicated in targeting or scaffolding processes. By yeast two-hybrid screenings and coimmunoprecipitation, we show here that p76RBE is a specific binding protein of RhoB and binds selectively to the GTP-bound form of this small GTPase. p76RBE also binds in vitro to components of the cytoskeleton, including cytokeratin 18. p76RBE is essentially cytoplasmic in transfected COS-7 mammalian cells and seems to be recruited to an endosomal compartment when coexpressed with the activated form of RhoB. p76RBE was shown to be mainly expressed in tissues with high secretion activity. Our data suggest that p76RBE could play a key role between RhoB and potential downstream elements needed under stimulation of the thyrotropin/cAMP pathway in thyrocytes and responsible for intracellular motile phenomena such as the endocytosis involved in the thyroid secretory process.     

Photoluminescence emission from nanostructured porous preparations of CdS–ZnTiO3 assembled nanoparticles

This study reports the structural and optical properties of CdS/ZnTiO₃ nanocomposites prepared using a chemical bath and different titanate concentrations. Commercial ZnTiO₃ nanoparticles were introduced into a chemical bath that had been used to produce CdS semiconductor nanoparticles (NPs). Here, the growing CdS crystallites precipitated onto the suspended zinc titanate NPs. X‐ray diffraction patterns revealed that samples of CdS/ZnTiO₃ nanopowders were made of cubic ZnTiO₃ and hexagonal CdS wurtzite. The morphology of the particles was studied using transmission electron microscopy and scanning electron microscopy images. These images demonstrated the different characteristics of the CdS/ZnTiO₃ nanocomposites and their dependence on titanate concentration when placed into the CdS‐growing solution. Photoluminescence spectra showed three main emission bands for the electron transitions in the CdS/ZnTiO₃ composite. This composite produced three photoluminescence bands, the intensities of which depended on composite shape, which in turn depended on the relative concentrations of CdS and ZnTiO₃.     

Two new trochids of the genus <Emphasis Type="Italic">Antimargarita</Emphasis> (Gastropoda: Vetigastropoda: Trochidae) from the Bellingshausen Sea and South Shetland Islands,Antarctica

Two new trochids of the genus Antimargarita, A. powelli and A. bentarti, from the Antarctic waters are described here. A. powelli, from the Bellingshausen Sea, is distinguished by its rounded whorls, numerous spiral cords, a radula with seven lateral teeth at each side of the rachidian, and an epipodium with eight pairs of tentacles. A. bentarti, from the South Shetland Islands, is characterized by having a shell outline gradated by prominent primary spiral cords, a radula with five lateral teeth at each side of the rachidian and an epipodium with six tentacles on the left side. The diagnostic features for Antimargarita are redefined considering both shell and anatomical features and its suprageneric placement is discussed.     

Synthesis and antiprotozoan evaluation of new alkyl-linked bis(2-thioxo-[1,3,5]thiadiazinan-3-yl) carboxylic acids

Two new series of several alkyl-linked bis(2-thioxo-[1,3,5]thiadiazinan-3-yl) carboxylic acids were synthesized in a two step procedure from the corresponding alkyl bis-dithiocarbamic salt intermediary. The novel compounds were evaluated for their activity in vitro against Trypanosoma cruzi strain CL (clone CL B5) and Trichomonas vaginalis strain JH 31A.