BMS309403 Stimulates Glucose Uptake in Myotubes through Activation of AMP-Activated Protein Kinase

BMS309403 is a biphenyl azole inhibitor against fatty acid binding protein 4 (FABP4) and regarded as a lead compound for effective treatment of obesity related cardio-metabolic diseases. Here we discovered an off-target activity of BMS309403 in that it stimulates glucose uptake in C2C12 myotubes in a temporal and dose dependent manner via activation of AMP-activated protein kinase (AMPK) signaling pathway but independent of FABPs. Further analysis indicated that BMS309403 activates AMPK through increasing the ratio of intracellular AMP:ATP while decreasing mitochondrial membrane potential. These findings provide mechanistic insights on the action of BMS309403.     

The role of PRKCH gene variants in coronary artery disease in a Chinese population

The aim of the present study was to assess the influences of PRKCH gene variants (1425G/A and _15) on the risk of coronary artery disease (CAD) in a Chinese population. Our study population consisted of 470 CAD patients and 434 control subjects. The alleles frequencies of the two variants were significantly higher among CAD patients than control subjects (P = 0.001 for 1425G/A and P = 0.001 for _15, respectively). In the CAD group, the A allele carriers of 1425G/A and _15 polymorphisms had higher low-density lipoprotein cholesterol (LDL-C) levels than homozygote G allele carriers (P = 0.001 and P = 0.021, respectively). In a multiple logistic regression model adjusted for age, sex, body mass index (BMI), etc., a markedly increased risk of developing CAD was found in subjects carrying GA or AA genotype (P = 0.005 and P = 0.018, respectively). In conclusion, we observed that there was a remarkable association of minor alleles (1425G/A and _15) in the PRKCH gene with an elevated risk of CAD and increased levels of LDL-C in this Chinese population.     

Nanoscale Compositionally Graded Thin‐Film Electrolyte Membranes for Low‐Temperature Solid Oxide Fuel Cells

Controllable fabrication of compositionally graded Gd_0.1Ce_0.9O_2‐δ and Y_0.16Zr_0.84O_2‐δ electrolytes using co‐sputtering is demonstrated. Self‐supported membranes were lithographically fabricated to employ the new electrolytes into thin film solid oxide fuel cells. Devices integrating such electrolytes demonstrate performance of over 1175 mW cm^?2 and 665 mW cm^?2 at 520 °C using hydrogen and methane as fuel, respectively. The results present a general strategy to fabricate nanoscale functionally graded materials with selective interfacial functionality for energy conversion.     

Eliciting 10E8-like antibodies by the membrane proximal external region peptide of HIV-1 in guinea pigs

Objective

To develop an immunotherapy for HIV that can elicit 10E8-like broadly-neutralizing antibodies in guinea pigs, using a multiple antigen peptide (MAP) system as the platform and 10E8 peptide as the epitope.

Results

The immunogen, 10E8-MAP₄, was synthetized using the MAP system. The synthetic 10E8-MAP₄ was stable, and the epitopes could be exposed for recognition. In addition, the 10E8 epitope was present in an α-helical structure, which was hypothesized to aid in the generation of neutralizing antibodies. In vivo analysis showed that 10E8-MAP₄ could efficiently elicit HIV binding antibodies in guinea pigs, although only weak neutralizing activities were observed.

Conclusions

Multiple antigen peptide is an excellent vaccine platform for generating binding antibodies, but may elicit weak neutralizing antibodies for HIV.

     

Rapid and simple method for the most-probable-number estimation of arsenic-reducing bacteria.

A rapid and simple most-probable-number (MPN) procedure for the enumeration of dissimilatory arsenic-reducing bacteria (DARB) is presented. The method is based on the specific detection of arsenite, the end product of anaerobic arsenate respiration, by a precipitation reaction with sulfide. After 4 weeks of incubation, the medium for the MPN method is acidified to pH 6 and sulfide is added to a final concentration of about 1 mM. The brightly yellow arsenic trisulfide precipitates immediately and can easily be scored at arsenite concentrations as low as 0.05 mM. Abiotic reduction of arsenate upon sulfide addition, which could yield false positives, apparently produces a soluble As-S intermediate, which does not precipitate until about 1 h after sulfide addition. Using the new MPN method, population estimates of pure cultures of DARB were similar to direct cell counts. MPNs of environmental water and sediment samples yielded DARB numbers between 10(1) and 10(5) cells per ml or gram (dry weight), respectively. Poisoned and sterilized controls showed that potential abiotic reductants in environmental samples did not interfere with the MPN estimates. A major advantage is that the assay can be easily scaled to a microtiter plate format, enabling analysis of large numbers of samples by use of multichannel pipettors. Overall, the MPN method provides a rapid and simple means for estimating population sizes of DARB, a diverse group of organisms for which no comprehensive molecular markers have been developed yet.     

Arf proteins bind to mitotic kinesin-like protein 1 (MKLP1) in a GTP-dependent fashion.

Arf proteins comprise a family of 21-kDa GTP-binding proteins with many proposed functions in mammalian cells, including the regulation of several steps of membrane transport, maintenance of organelle integrity, and activation of phospholipase D. We performed a yeast two-hybrid screen of human cDNA libraries using a dominant activating allele, [Q71L], of human Arf3 as bait. Eleven independent isolates contained plasmids encoding the C-terminal tail of mitotic kinesin-like protein-1 (MKLP1). Further deletion mapping allowed the identification of an 88 amino acid Arf3 binding domain in the C-terminus of MKLP1. This domain has no clear homology to other Arf binding proteins or to other proteins in the protein databases. The C-terminal domain of MKLP1 was expressed and purified from bacteria as a GST fusion protein and shown to bind Arf3 in a GTP-dependent fashion. A screen for mutations in Arf3 that specifically lost the ability to bind MKLP1 identified 10 of 14 point mutations in the GTP-sensitive switch I or switch II regions of Arf3. Two-hybrid assays of the C-terminal domain of MKLP1 with each of the human Arf isoforms revealed strong interaction with each. Taken together, these data are all supportive of the conclusion that activated Arf proteins bind to the C-terminal "tail" domain of MKLP1.     

Effects of Pb2+ on the transient outward potassium current in acutely dissociated rat hippocampal neurons

Modulation of the voltage-dependent transient outward potassium current (IA) by Pb2+ was studied in acutely dissociated rat hippocampal pyramidal cells from the CA1 region at postnatal ages 7-14 days using the conventional whole-cell patch-clamp technique. In the presence of different concentrations of external Pb2+, the initial delay and activation time of IA were concentration-dependently lengthened. In particular, the initial delay was even longer in 1 mM Pb2+, showing no signs of saturation. Pb2+ also slowed the inactivation of IA, for decay time constants in the presence of Pb2+ were increased under the same experimental protocols. The activation curves, which were reasonably fitted by a single Boltzmann function, illustrated that Pb2+ increased the voltage threshold of IA and shifted the normalized activation current-voltage curves to more depolarizing voltage commands. Moreover, Pb2+ significantly affected the steady-state inactivation of IA. The application of Pb 2+ made the curves of the steady-state inactivation of IA shift to more depolarizing voltages with little change in the slopes factors. In brief, the results demonstrated that Pb2+ is a dose- and voltage-dependent, reversible blocker of IA currents of hippocampal CA1 neurons. The observations were fitted by the revised "Kuo and Chen type model", which postulates a Pb2+-selective site near the pore of the IA channel and that modulation of the IA channel by Pb2+ is the result of the competitive influences of Pb2+ on opening and inactivating different pathways.     

Effectors increase the affinity of ADP-ribosylation factor for GTP to increase binding

The stoichiometry of the binding of GTP to ADP-ribosylation factor (ARF) proteins, normally quite low at approximately 0.05 mol/mol protein, was found to increase to a maximum of 1 mol/mol in the presence of effectors. The mechanism of this action was found to result from the ability of these effectors to increase the affinity of ARF for activating guanine nucleotide triphosphates. The existence of a conformation of ARF with low affinity (>100 micrometer) for GTP is proposed. The actions of effectors to increase the equilibrium binding of GTP is interpreted as evidence that these same effectors interact with and modulate the affinity of the inactive ARF for GTP. A new model for these interactions among ARF, effectors, and GTP is proposed, and a preliminary test in cells is supportive of these observations with relevance to signaling in cells.     

AtCLH2, a Typical but Possibly Distinctive Chiorophyllase Gene in Arabidopsis

Chlorophyllase (EC 3.1.1.14) is involved in the first step of chlorophyll degradation. Isolation of chlorophyllase genes greatly facilitates characterization of chlorophyllase properties and elucidation of molecular regulation of their in vivo activities. There are two chlorophyllase genes, AtCLH1 and AtCLH2, in Arabidopsis thallana. The in vivo roles of AtCLH1 have been reported previously. However, few studies have been carried out on AtCLH2. Here,we show that purified recombinant Chlase2, encoded by AtCLH2, exhibits in vitro chlorophyllase activity. Interestingly,"activation" of in vitro activity of the recombinant Chlase2 required higher concentrations of a detergent or a polar solvent. To determine its activity in vivo, the expression of AtCLH2 was inhibited by RNA interference. RNAi plants showed decreased contents of chlorophyllide without a substantial change in the total amount of the extractable chlorophyll and consequently presented lower chlorophyllide to chlorophyll ratios in their leaves. In addition, the two AtCLHs exhibited differential expression patterns. Our results suggest that AtCLH2 might play a distinctive role in chlorophyll catabolism in vivo.