Solution properties of gellan gum: change in chain stiffness between single- and double-stranded chains

Nine samples of gellan gum in the sodium form, ranging in weight-average molar mass from 3.47 x 10(4) to 1.15 x 10(5) at 40 degrees C, were investigated by static and dynamic light scattering and viscometry in 25 mM aqueous NaCl both at 40 and at 25 degrees C. The ratios of the molar mass at 25 degrees C (in the ordered state) to that at 40 degrees C (in the disordered state) were in the range of 1.99 to 2.07, supporting the scheme of the conformational transition of gellan gum between a disassociated single chain and an associated chain composed of two molecules. Focusing on the effects of polydispersity, the intrinsic viscosities, radii of gyration, and hydrodynamic radii were analyzed on the basis of unperturbed wormlike chain models. The persistence lengths were evaluated as 9.4 nm at 40 degrees C and 98 nm at 25 degrees C.     

Efficient asymmetric syntheses, determination of absolute configurations and biological activities of 1-[4,4-bis(4-fluorophenyl)butyl]-4-[2-hydroxy-3-(phenylamino)propyl]piperazine as a novel potent dopamine uptake inhibitor in the central nervous system

An efficient asymmetric synthesis of the chiral N-(3-chloro-2-hydroxypropyl)anilines (2a and 2b) was achieved through the regioselective ring-opening reaction of chiral epichlorohydrin with aniline. This was applied to an asymmetric synthesis of the enantiomers of 1-[4,4-bis(4-fluorophenyl)butyl]-4-[2-hydroxy-3-(phenylamino)propyl]piperazine 1 as a novel potent dopamine uptake inhibitor. Both enantiomers as trihydrochlorides, 4a.3HCl and 4b.3HCl, could be synthesized in good total yields and optical purities of 100% ee in three steps synthesis, respectively. The absolute configurations of 4a.3HCl and 4b.3HCl were determined using the modified Mosher's method with the related compounds, the intermediates (2a and 2b) and the free bases (4a and 4b). The analytical results indicated that 4a.3HCl and 4b.3HCl have the (S)- and (R)-configuration, respectively, and a series of reactions to provide them proceeded without the apparent influence on the stereochemistry at the chiral centers. In in vitro pharmacological evaluations, 4a.3HCl and 4b.3HCl showed potent dopamine transporter binding affinities, high dopamine, moderate serotonin, and weak norepinephrine uptake inhibitory activities, and 4a.3HCl exhibited a more potent and selective dopamine uptake inhibition over the serotonin or norepinephrine uptake inhibition as compared with 4b.3HCl. An ex vivo evaluation revealed that the oral administrations of both enantiomers at a dose of 30 mg/kg in rats displayed apparent dopamine uptake inhibitory activities and 4a.3HCl had a stronger tendency to inhibit dopamine uptake compared with 4b.3HCl.     

Piericidins C5 and C6: new 4-pyridinol compounds produced by Streptomyces sp. and Nocardioides sp

Piericidins C5 (1) and C6 (2), two new members of the piericidin family, were isolated from a Streptomyces sp. and a Nocardioides sp., together with known piericidins C1 (3), C2 (4), C3 (5), C4 (6), D1 (7), and A3 (8). The structures were determined on the basis of their spectroscopic data. Both new compounds inhibited cell division of fertilized starfish (Asterina pectinifera) eggs at the minimum inhibitory concentration of 0.09 microg/mL.     

Cutting edge: a potent adjuvant effect of ligand to receptor activator of NF-kappa B gene for inducing antigen-specific CD8+ T cell response by DNA and viral vector vaccination

The ligand to receptor activator of NF-kappaB (RANK-L)/RANK interaction has been implicated in CD40 ligand/CD40-independent T cell priming by dendritic cells. In this report, we show that the coadministration of the RANK-L gene with a Trypanosoma cruzi gene markedly enhances the induction of Trypanosoma Ag-specific CD8(+) T cells and improves the DNA vaccine efficacy. A similarly potent adjuvant effect of the RANK-L gene on the induction of Ag-specific CD8(+) T cells was also observed when recombinant influenza virus expressing murine malaria Ag was used as an immunogen. In contrast, the coadministration of the CD40L gene was not effective in these systems. Our results demonstrated, for the first time, the potent immunostimulatory effect of the RANK-L gene to improve the CD8(+) T cell-mediated immunity against infectious agents.     

A human case of gnathostomiasis nipponica confirmed indirectly by finding infective larvae in leftover largemouth bass meat

A human case of creeping eruption due to Gnathostoma nipponicum was confirmed indirectly by finding infective advanced third-stage larvae in leftover largemouth bass meat. This is the first report indicating that the largemouth bass (Micropterus salmoides) serves as a source of G. nipponicum infection in humans.     

Na+/Mg2+ transporter acts as a Mg2+ buffering mechanism in PC12 cells

Mg(2+) buffering mechanisms in PC12 cells were demonstrated with particular focus on the role of the Na(+)/Mg(2+) transporter by using a newly developed Mg(2+) indicator, KMG-20, and also a Na(+) indicator, Sodium Green. Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP), a protonophore, induced a transient increase in the intracellular Mg(2+) concentration ([Mg(2+)](i)). The rate of decrease of [Mg(2+)](i) was slower in a Na(+)-free extracellular medium, suggesting the coupling of Na(+) influx and Mg(2+) efflux. Na(+) influxes were different for normal and imipramine- (a putative inhibitor of the Na(+)/Mg(2+) transporter) containing solutions. FCCP induced a rapid increase in [Na(+)](i) in the normal solution, while the increase was gradual in the imipramine-containing solution. The rate of decrease of [Mg(2+)](i) in the imipramine-containing solution was also slower than that in the normal solution. From these results, we show that the main buffering mechanism for excess Mg(2+) depends on the Na(+)/Mg(2+) transporter in PC12 cells.     

Photoreceptor synaptic protein HRG4 (UNC119) interacts with ARL2 via a putative conserved domain

Human retinal gene 4 (HRG4) (UNC119) is a photoreceptor synaptic protein of unknown function, shown when mutated to cause retinal degeneration in a patient and in a confirmatory transgenic model. ADP-ribosylation factor-like protein 2 (ARL2) was identified as an interactor of HRG4 by the yeast two-hybrid strategy. The presence of ARL2 in the retina and co-localization with HRG4 was confirmed by Western blot and double immunofluorescence analysis, respectively. The interaction of ARL2 with HRG4 was further confirmed by co-immunoprecipitation and direct binding analysis. Phosphodiesterase delta (PDEdelta) is an ARL2-binding protein homologous to HRG4. Amino acid residues of PDEdelta involved in binding ARL2 and forming a hydrophobic pocket were shown to be highly conserved in HRG4, suggesting similarity in binding mechanism and function.     

Reduction of phosphodiesterase 3B gene expression in peroxisome proliferator-activated receptor gamma (+/-) mice independent of adipocyte size

Phosphodiesterase 3B (PDE3B) gene expression is generally reduced in large adipocytes of obese, insulin-resistant mice. This reduced gene expression is restored by peroxisome proliferator-activated receptor (PPAR) gamma ligands accompanied by a reduced fat cell size. To determine whether PDE3B gene expression is regulated by PPAR gamma itself, we analyzed lean PPAR gamma (+/-) mice with adipocyte size comparable to control PPAR gamma (+/+) mice. In adipocytes of PPAR gamma (+/-) mice, PDE3B mRNA and protein were both reduced to 63% of wild-type levels. Basal PDE activity tended to be decreased to 70% of wild-type levels, and, similarly, insulin-induced PDE activity was significantly decreased to 70%. Thus, PPAR gamma is required for PDE3B gene expression independent of adipocyte size.