Discovery of Protein Disulfide Isomerase P5 Inhibitors that Reduce the Secretion of MICA from Cancer Cells

In order to regulate the activity of P5, which is a member of the protein disulfide isomerase family, we screened a chemical compound library for P5‐specific inhibitors, and identified two candidate compounds (anacardic acid and NSC74859). Interestingly, anacardic acid inhibited the reductase activity of P5, but did not inhibit the activity of protein disulfide isomerase (PDI), thiol‐disulfide oxidoreductase ERp57, or thioredoxin. NSC74859 inhibited all these enzymes. When we examined the effects of these compounds on the secretion of soluble major histocompatibility complex class‐I‐related gene A (MICA) from cancer cells, anacardic acid was found to decrease secretion. In addition, anacardic acid was found to reduce the concentration of glutathione up‐regulated by the anticancer drug 17‐demethoxygeldanamycin in cancer cells. These results suggest that anacardic acid can both inhibit P5 reductase activity and decrease the secretion of soluble MICA from cancer cells. It might be a novel and potent anticancer treatment by targeting P5 on the surface of cancer cells.     

Investigation of ion adsorption properties of sulfobetaine gel and relationship with its swelling behavior

The adsorption of cations and anions in nitrate solutions on N,N-dimethyl(acrylamidopropyl)ammonium propane sulfonate (DMAAPS) gels prepared using various cross-linker and monomer concentrations was investigated. The influence of the temperature and nitrate concentration on the adsorption properties of the gel was evaluated, demonstrating simultaneous adsorption of cations and anions. The amount of Zn²⁺ adsorbed on the gel in Zn(NO₃)₂ solution increased as the cross-linker and monomer concentrations used in the gel preparation increased. For the gel prepared using a higher cross-linker or monomer concentration, elevation of the temperature did not induce any significant change in the amount of Zn²⁺ adsorbed on the gel. Furthermore, for the gel prepared using a lower cross-linker or monomer concentration, the amount of Zn²⁺ adsorbed on the gel decreased significantly as the temperature increased. In addition, an interesting correlation between the degree of swelling of the gel and the amount of Zn²⁺ adsorbed on the gel was found. As the degree of swelling decreased, the adsorption amount increased to eventually achieve a constant value.     

Computational Prediction of O-linked Glycosylation Sites That Preferentially Map on Intrinsically Disordered Regions of Extracellular Proteins

O-glycosylation of mammalian proteins is one of the important posttranslational modifications. We applied a support vector machine (SVM) to predict whether Ser or Thr is glycosylated, in order to elucidate the O-glycosylation mechanism. O-glycosylated sites were often found clustered along the sequence, whereas other sites were located sporadically. Therefore, we developed two types of SVMs for predicting clustered and isolated sites separately. We found that the amino acid composition was effective for predicting the clustered type, whereas the site-specific algorithm was effective for the isolated type. The highest prediction accuracy for the clustered type was 74%, while that for the isolated type was 79%. The existence frequency of amino acids around the O-glycosylation sites was different in the two types: namely, Pro, Val and Ala had high existence probabilities at each specific position relative to a glycosylation site, especially for the isolated type. Independent component analyses for the amino acid sequences around O-glycosylation sites showed the position-specific existences of the identified amino acids as independent components. The O-glycosylation sites were preferentially located within intrinsically disordered regions of extracellular proteins: particularly, more than 90% of the clustered O-GalNAc glycosylation sites were observed in intrinsically disordered regions. This feature could be the key for understanding the non-conservation property of O-glycosylation, and its role in functional diversity and structural stability.     

Viscosity and Thermal Conductivity of 1-Hexyl-3-methylimidazolium Tetrafluoroborate and 1-Octyl-3-methylimidazolium Tetrafluoroborate at Pressures up to 20?MPa

Viscosity and thermal conductivity values are reported for a series of 1-alkyl-3-methylimidazolium tetrafluoroborate compounds with hexyl (1-hexyl-3-methylimidazolium tetrafluoroborate) and octyl (1-octyl-3-methylimidazolium tetrafluoroborate) groups. The viscosity was measured with a rolling-ball viscometer at 293.15 K to 353.15 K and pressures up to 20.0?MPa. The experimental values were correlated with a hybrid VFT–Tait equation. The thermal conductivity was measured using the transient short hot-wire method at 294 K to 335 K and pressures up to 20.0?MPa. The experimental values at 293.15 K and 0.1?MPa agreed with the predicted values proposed by Fr?ba et?al.     

Bacterial contamination in an egg-breaking factory and its control

From January to November, 2003, bacterial contamination was surveyed in a small egg-breaking factory that produced non pasteurized liquid egg. Test egg samples were taken at various stages of the egg processing operation. Salmonella Enteritidis was isolated from liquid egg yolk and liquid egg white on October, but was not found in any other samples (50 liquid egg samples, 21 containers and 94 attached production facilities and gloves). The data suggest that the contamination rate (3.8%) is lower than those reported previously. Levels of bacterial standard plate counts, gram-positive bacterial counts and gram-negative bacterial counts were in the ranges of 2 to 5 log CFU/g, 2 to 3 log CFU/g, 2 to 5 log CFU/g, respectively. Liquid egg containers returned from customers was contaminated with bacteria at the level of 8 log CFU per container. However, washing and application of a sanitizer containing sodium hypochlorite reduced the bacterial counts.     

Deciphering cellular functions of protein phosphatases by comparison of gene expression profiles in Saccharomyces cerevisiae

Expression profiles of protein phosphatase (PPase) disruptants were analyzed by use of Pearson's correlation coefficient to find profiles that correlated with those of 316 Reference Gene (RG) disruptants harboring deletions in genes with known functions. Twenty-six Δppase disruptants exhibited either a positive or negative correlation with 94 RG disruptants when the p value for Pearson's correlation coefficient was > 0.2. Some of the predictions that arose from this analysis were tested experimentally and several new Δppase phenotypes were found. Notably, Δsit4 and Δsiw14 disruptants exhibited hygromycin B sensitivity, Δsit4 and Δptc1 disruptants grew slowly on glycerol medium, the Δptc1 disruptant was found to be sensitive to calcofluor white and congo red, while the Δppg1 disruptant was found to be sensitive to congo red. Because on-going analysis of expression profiles of Saccharomyces cerevisiae disruptants is rapidly generating new data, we suggest that the approach used in the present study to explore PPase function is also applicable to other genes.     

All solid-state polymer electrolytes prepared from a hyper-branched graft polymer using atom transfer radical polymerization

We propose an all solid-state (liquid free) polymer electrolyte (SPE) prepared from a hyper-branched graft copolymer. The graft copolymer consisting of a poly(methyl methacrylate) main chain and poly(ethylene glycol) methyl ether methacrylate side chains was synthesized by atom transfer radical polymerization changing the average chain distance between side chains, side chain length and branched chain length of the proposed structure of the graft copolymer. The ionic conductivity of the SPEs increases with increasing the side chain length, branched chain length and/or average distance between the side chains. The ionic conductivity of the SPE prepared from POEM₉ whose POEM content = 51 wt% shows 2 × 10⁻⁵ S/cm at 30 °C. The tensile strength of the SPEs decreases with increases the side chain length, branched chain length and/or average distance between the side chains. These results indicate that a SPE prepared from the hyper-branched graft copolymer has potential to be applied to an all-solid polymer electrolyte.