WP1066, a small molecule inhibitor of the JAK/STAT3 pathway, inhibits ceramide glucosyltransferase activity

WP1066 is a well-known inhibitor of the JAK/STAT3 signaling pathway. By a screen of known small molecule inhibitors of various enzymes and protein factors, we identified WP1066 as a ceramide glucosyltransferase inhibitor. Ceramide glucosyltransferase catalyzes the first glycosylation step during glycosphingolipid synthesis. We found that WP1066 inhibited the activity of ceramide glucosyltransferase with an IC₅₀ of 7.2 μM, and that its action was independent of JAK/STAT3 pathway blockade. Moreover, the modes of inhibition of ceramide glucosyltransferase were uncompetitive with respect to both C₆-NBD-cermide and UDP-glucose.

First successful ionization of Lr (Z = 103) by a surface-ionization technique

We have developed a surface ionization ion-source as part of the JAEA-ISOL (Isotope Separator On-Line) setup, which is coupled to a He/CdI2 gas-jet transport system to determine the first ionization potential of the heaviest actinide lawrencium (Lr, Z = 103). The new ion-source is an improved version of the previous source that provided good ionization efficiencies for lanthanides. An additional filament was newly installed to give better control over its operation. We report, here, on the development of the new gas-jet coupled surface ion-source and on the first successful ionization and mass separation of 27-s (256)Lr produced in the (249)Cf + (11)B reaction.

Functional cloning of genes that suppress oxidative stress-induced cell death: TCTP prevents hydrogen peroxide-induced cell death

We used retroviral-mediated expression cloning to identify cDNAs that inhibit cell death induced by oxidative stress. To isolate the genes, we introduced a murine embryonic retroviral cDNA library into NIH/3T3 cells, and selected for cells resistant to hydrogen peroxide. The surviving cells were cloned, and the integrated cDNAs were rescued by polymerase chain reaction. Several of the isolated cDNAs are known to be involved in modulating the redox state of cells. Other cDNAs encode proteins known to suppress apoptosis caused by reasons other than oxidative stress. These included polyadenylate-binding protein, cytosolic 1 (Pabpc1) and translationally controlled tumor protein (TCTP).

Identification and characterization of a novel alternative splice variant of mouse GMx33alpha/GPP34

We have cloned and characterized a novel splice variant of mouse GMx33alpha/Golgi-associated protein of 34 kDa (GPP34), hereby designated GMx33alphaV/GPP34V. This splice variant skips the second and third exons, and the resulting frame shift generates a stop codon in the fourth exon. GMx33alphaV/GPP34V is comprised of 81 amino acid residues derived from the N-terminal end of the full length protein and corresponds to approximately one-third of the full length GMx33alpha/GPP34 sequence with a calculated molecular mass of 8900. In contrast to GMx33alpha/GPP34 mRNA which is expressed at similar levels in various tissues, GMx33alphaV/GPP34V mRNA was differentially expressed when examined by RT-PCR. Compared to other tissues, skeletal muscle showed relatively strong expression of GMx33alphaV/GPP34V mRNA. This splice variant cDNA was also detected in a human cell line.

Characterization of Zeolite NaA Membrane by FTIR-ATR and Its Application to the Rapid Evaluation of Dehydration Performance

A zeolite NaA (LTA) membrane supported by an alumina porous support tube was characterized by Fourier Transform Infrared Attenuated Total Reflectance method (FTIR-ATR) with a diamond prism as the waveguide. A method using the FTIR-ATR was developed to estimate rapidly the EtOH/H2O pervaporation (PV) performance of the membrane. The Si-O asymmetric stretching vibration region of LTA membrane spectra synthesized hydrothermally on seeded alumina substrates showed a bimodal peak (830 - 1200 cm(-1)). The two peaks were assigned to a surface LTA directly derived from the seed crystal (1012 cm(-1)), and to LTA and/or amorphous substances embedded in the alumina porous support (930 cm(-1)). The spectrum from LTA membrane synthesized on nonseeded alumina substrate, however, showed a single broad peak similar to the powder-formed one. These results indicate that the Si-O spectral shape of the LTA membrane is influenced strongly by the synthesis method. Also, the FTIR-ATR of the LTA membrane can detect the Si-O peaks as part of the depth information. It was first shown that the relative ratio (930 cm(-1)/1012 cm(-1)) of the two Si-O peaks from the LTA membranes on seeded alumina substrates closely relates to the water selectivity (alpha) in the PV of EtOH/H2O mixture; the alpha increases exponentially with the peak ratio. This result suggests that the differences in the vertical distribution of LTA crystal and amorphous material strongly affect the dehydration performance in the EtOH/H2O PV, that is, the amorphous-like material embedded in the alumina porous support plays an important role. The relative peak ratio measurement can be used for the rapid evaluation of the dehydration performance of the membrane.

Hydrovapothermal conversion of tetraethoxysilane vapor to polycrystalline zeolite layer by in situ gelationElectronic supplementary information (ESI) available: SEM images and seeding method. See http://www.rsc.org/suppdata/cc/b4/b400207p/

Zeolite membrane has been fabricated on porous alumina substrate in a single continuous process of gelation and subsequent crystallization while suppressing nucleation of zeolite powder in the bulk.

Defective presentation of the CD1d1-restricted natural Va14Ja18 NKT lymphocyte antigen caused by beta-D-glucosylceramide synthase deficiency

Va14Ja18 natural T (NKT) cells play an immunoregulatory role, which is controlled by a self glycolipid(s) presented by CD1d. Although the synthetic antigen alpha-D-galactosylceramide (alpha-D-GalCer) stimulates all Va14Ja18 NKT cells, alpha-anomeric D-glycosylceramides are currently unknown in mammals. We have used beta-D-GalCer-deficient mice and beta-D-glucosylceramide (beta-D-GlcCer)-deficient cells to define the chemical nature of a natural NKT cell antigen. beta-D-GalCer-deficient mice exhibit normal NKT cell development and function, and cells from these animals potently stimulate NKT hybridomas. In striking contrast, the same hybridomas fail to react to CD1d1 expressed by a beta-D-GlcCer-deficient cell line. Importantly, human beta-D-GlcCer synthase cDNA transfer, and hence the biosynthesis of beta-D-GlcCer, restores the recognition of mutant cells expressing CD1d1 by the Va14Ja18 NKT hybridomas. Additionally, suppression of beta-D-GlcCer synthesis inhibits antigen presentation to Va14Ja18 NKT cells. The possibility that beta-D-GlcCer itself is the natural NKT cell antigen was excluded because it was unable to activate NKT hybridomas in a cell-free antigen-presentation assay. These findings suggest that beta-D-GlcCer may play an important role in generating and/or loading a natural Va14Ja18 NKT antigen.

Glucosylceramide synthesis and synthase expression protect against ceramide-induced stress

Ceramides (Cers), critical for epidermal barrier function, also can inhibit keratinocyte proliferation, while glucosylceramides (GlcCers) exert pro-mitogenic effects. Since alterations in Cer-to-GlcCer ratios appear to modulate cellular growth versus apoptosis, we assessed whether keratinocytes up-regulate GlcCer synthesis as a protective mechanism against Cer-induced stress. Exogenous sphingomyelinase (SMase) treatment of cultured human keratinocytes (CHK) initially decreased proliferation and cellular sphingomyelin (50-60% decrease; P < 0.001), and increased Cer levels (6.1- to 6.8-fold; P < 0.001). Proliferation recovered to normal rates by 24 h, in parallel with increased cellular GlcCer. Both GlcCer synthesis and GlcCer synthase activity increased significantly by 8 h following SMase (8.2- and 2.4-fold, respectively; P < 0.01 each vs. control), attributed to antecedent increases in GlcCer synthase mRNA and protein expression. Further evidence that GlcCer production is responsible for normalized CHK proliferation includes: a) attenuation of SMase-induced inhibition of proliferation by exogenous GlcCer; and b) enhancement of the SMase effect in cells cotreated with the GlcCer synthase inhibitor, PDMP (D-threo-1-phenyl-2(decanoylamino)-3-morpholino-1-propanol). Finally, although proliferation in immortalized, nontransformed keratinocytes (HaCaT) also was inhibited by SMase, HaCaT cells that overexpress GlcCer synthase were resistant to this effect. Thus, SMase-induced stress initiates a response in keratinocytes that includes upregulation of GlcCer synthesis which may protect against the deleterious effects of excess Cer.

Intuitive reasoning about probability: theoretical and experimental analyses of the "problem of three prisoners"

Among various Bayesian problems of probability, the "problem of three prisoners" (Lindley, 1971; Mosteller, 1965) is an especially good example which illustrates the drastic discrepancy between intuitive reasoning and mathematical formal reasoning about probability. In particular, it raises intriguing questions concerning the mathematical and cognitive relevance of factors such as prior probabilities and the context in which certain information is given. In the current paper, we report a new version of the problem which turned out to be even more counterintuitive. This new version was also designed so that different inferential schemes would lead to separate estimates of posterior probability. The data obtained from questionnaires and theoretical analyses of the original and modified problems suggest that: (1) The psychological processes of intuitive reasoning are qualitatively different from mathematical reasoning. (2) The tendency to neglect prior probabilities (Tversky & Kahneman, 1974, 1982) is not always the critical factor for illusory judgments. (3) Intuitive judgments can be categorized by several, distinctive propositional beliefs from which the judgments are apparently derived. We call these prototypical, crude beliefs "subjective theorems," and discuss their nature and roles in the current paper.