Caveolin-1 triggers T-cell activation via CD26 in association with CARMA1

CD26 is a widely distributed 110-kDa cell surface glycoprotein with an important role in T-cell costimulation. We demonstrated previously that CD26 binds to caveolin-1 in antigen-presenting cells, and following exogenous CD26 stimulation, Tollip and IRAK-1 disengage from caveolin-1 in antigen-presenting cells. IRAK-1 is then subsequently phosphorylated to up-regulate CD86 expression, resulting in subsequent T-cell proliferation. However, it is unclear whether caveolin-1 is a costimulatory ligand for CD26 in T-cells. Using soluble caveolin-1-Fc fusion protein, we now show that caveolin-1 is the costimulatory ligand for CD26, and that ligation of CD26 by caveolin-1 induces T-cell proliferation and NF-kappaB activation in a T-cell receptor/CD3-dependent manner. We also demonstrated that the cytoplasmic tail of CD26 interacts with CARMA1 in T-cells, resulting in signaling events that lead to NF-kappaB activation. Ligation of CD26 by caveolin-1 recruits a complex consisting of CD26, CARMA1, Bcl10, and IkappaB kinase to lipid rafts. Taken together, our findings provide novel insights into the regulation of T-cell costimulation via the CD26 molecule.     

Semi-nested polymerase chain reaction for detection of toxigenic <Emphasis Type="Italic">Vibrio cholerae</Emphasis> from environmental water samples

A rapid and sensitive direct cell semi-nested PCR assay was developed for the detection of viable toxigenic V. cholerae in environmental water samples. The semi-nested PCR assay amplified cholera toxin (ctxA2B) gene present in the toxigenic V. cholerae. The detection sensitivity of direct cell semi-nested PCR was 2 × 10³ CFU of V. cholerae whereas direct cell single-step PCR could detect 2 × 10⁴ CFU of V. cholerae. The performance of the assay was evaluated using environmental water samples after spiking with known number of Vibrio cholerae O1. The spiked water samples were filtered through a 0.22 micrometer membrane and the bacteria retained on filters were enriched in alkaline peptone water and then used directly in the PCR assay. The semi-nested PCR procedure coupled with enrichment could detect less than 1 CFU/ml in ground water and sea water whereas 2 CFU/ml and 20 CFU/ml could be detected in pond water and tap water, respectively. The proposed method is simple, faster than the conventional detection assays and can be used for screening of drinking water or environmental water samples for the presence of toxigenic V. cholerae.     

The role of connexins in controlling cell growth and gene expression

The purpose of this paper is to provide a brief overview of current thinking on the role of connexins, in particular Cx43, in growth regulation, and a more detailed discussion as to potential mechanisms involved with an emphasis on gene expression. While the precise molecular mechanism by which connexins can affect the growth of normal or tumor cells remains elusive, a number of exciting reports have expanded our understanding and are presented in some detail. Thus, we will discuss (Section 2): the role of protein-protein interactions in integrating connexins into multiple signal transduction pathways; phosphorylation at specific sites and reversal of growth inhibition; the role of the carboxy-terminal regulatory domain as a signaling molecule. Some of our latest work on the potential functions of endogenously produced carboxy-terminal fragments of Cx43 are also presented (Section 3). Finally, Section 4 will pay tribute to the rapidly emerging realization that connexins such as Cx43 and Cx32 exert important and extensive effects on gene expression, particularly those genes linked to growth regulation.     

Modeling the interaction of coils with the local blood flow after coil embolization of intracranial aneurysms

Aneurysmal recanalization and coil compaction after coil embolization of intracranial aneurysms are seen in as many as 40% of cases. Higher packing density has been suggested to reduce both coil compaction and recanalization. Basilar bifurcation aneurysms remain a challenge due possibly to the hemodynamics of this specific aneurysm/parent vessel architecture, which subjects the coil mass at the aneurysm neck to elevated and repetitive impingement forces. In the present study, we propose a new modeling strategy that facilitates a better understanding of the complex interactions between detachable coils and the local blood flow. In particular, a semiheuristic porous media set of equations used to describe the intra-aneurysmal flow is coupled to the incompressible Navier-Stokes equations governing the dynamics of the flow in the involved vessels. The resulting system of equations is solved in a strongly coupled manner using a finite element formulation. Our results suggest that there is a complex interaction between the local hemodynamics and intra-aneurysmal flow that induces significant forces on the coil mass. Although higher packing densities have previously been advocated to reduce coil compaction, our simulations suggest that lower permeability of the coil mass at a given packing density could also promote faster intra-aneurysmal thrombosis due to increased residence times.     

Wangia profunda gen. nov., sp. nov., a novel marine bacterium of the family Flavobacteriaceae isolated from southern Okinawa Trough deep-sea sediment

An orange-pigmented, Gram-negative, nonmotile, strictly aerobic and oxidase- and catalase-positive bacterium (SM-A87(T)) was isolated from the deep-sea sediment of the southern Okinawa Trough area. The main fatty acids were i15 : 0, i17 : 0 3OH, i15 : 1 G, i17 : 1 omega 9c, 15 : 0, i15 : 0 3OH and summed feature 3 (comprising i-15 : 0 2OH and/or 16 : 1 omega 7c). MK-6 was the predominant respiratory quinone. DNA G+C content was 35.8 mol%. Flexirubin-type pigments were absent. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain SM-A87(T) formed a distinct lineage within the family Flavobacteriaceae, with <93% sequence similarity to the nearest strain of genus Salegentibacter. Moreover, strain SM-A87(T) could be distinguished from the nearest phylogenetic neighbors by a number of chemotaxonomic and phenotypic properties. On the basis of polyphasic analyses, it is proposed that strain SM-A87(T) be classified in a novel genus and a new species in the family Flavobacteriaceae, designated Wangia profunda gen. nov., sp. nov. The type strain is SM-A87(T) (CCTCC AB 206139(T)=DSM 18752).     

Identification and transcription of transfer RNA genes in dinoflagellate plastid minicircles

The dinoflagellate chloroplast genome is unique in that the genes are found on small circular DNA molecules carrying from one to three genes. In addition, only 14 of the typical chloroplast-located genes have so far been discovered on minicircles, while a number have been transferred to the nucleus. We have sequenced four new minicircles from the dinoflagellate Heterocapsa triquetra, three of which carry a single protein-coding gene (psbD, psbE, petD) and one that appears to be an "empty" circle. Using the tRNA prediction programs ARAGORN and tRNAscan-SE, tRNA-Met was found in the petD circle immediately downstream of the end of petD, while tRNA-Trp and tRNA-Pro were detected in the psbE and petD circles as well as in several chimeric circles of H. triquetra and the psbA minicircles of Heterocapsa pygmaea. RT-PCR showed that the tRNAs were co-transcribed with the protein-coding genes that preceded them, and cleaved from the precursor before a poly(U) tail was added to the mRNA.     

Synthesis and characterization of a perchlorotriphenylmethyl (trityl) triester radical: a potential sensor for superoxide and oxygen in biological systems

Synthesis and characterization of an inert perchlorotriphenylmethyl triester radical, PTM-TE, are reported. PTM-TE was prepared by a facile 3-step synthesis using Friedel-Crafts reaction of tetrachlorobenzene with chloroform followed by ethoxycarbonylation and subsequent oxidation. PTM-TE is paramagnetic and exhibits a single sharp EPR spectrum. In solution, the EPR linewidth of PTM-TE is highly sensitive to the dissolved oxygen content, thus enabling accurate measurement of oxygen concentration (oximetry). In addition, the radical also shows high reactivity towards superoxide. The ester radical has the potential for use as a high-sensitive probe for determination of oxygen concentration and superoxide in biological systems.     

Quinazoline derivatives as MC-I inhibitors: evaluation of myocardial uptake using Positron Emission Tomography in rat and non-human primate

Several quinazoline derivatives were made as mitochondrial complex 1 inhibitors. Compound 4 showed an IC(50) of 11.3 nM and was the most potent compound of this series. The (18)F analog of 4, [(18)F] 4, was injected in the rat and showed high and rapid heart uptake, fast liver clearance, and low blood uptake. Images obtained using a microPET showed clear delineation of the myocardium in normal rats and perfusion deficit in ischemic rats. In the non-human primate, [(18)F] 4 showed rapid uptake and clearance from the myocardium and high liver uptake.