Application of chiralcel OJ in supercritical fluid chromatography for the resolution of different groups of frequently used drug racemates

Supercritical fluid chromatography was applied to evaluate the direct chiral discriminative properties of Chiralcel OJ, a tris(4-methylbenzoate) cellulose column towards frequently administered drugs. Two groups of acidic drugs, profen and barbiturate derivatives, and a few basic drugs of the benzodiazepine type were analysed. The effect on enantioselectivity of carbon dioxide when using methanol are acetonitrile as primary modifier was studied. Acetonitrile proved to be a good alternative for methanol, especially for the profen compounds that were not well resolved using methanol. The results were compared to normal phase chromatographic applications on the same column. SFC was not necessarily superior to high-performance liquid chromatography. Chirality 9:126–132, 1997. © 1997 Wiley-Liss, Inc.     

Investigation of Decitabine Effects on HDAC3 and HDAC7 mRNA Expression in NALM-6 and HL-60 Cancer Cell Lines

Background:Decitabine is a potent anticancer hypomethylating agent and changes the gene expression through the gene''s promoter demethylation and also independently from DNA demethylation. So, the present study was designed to distinguish whether Decitabine, in addition to inhibitory effects on DNA methyltransferase, can change HDAC3 and HDAC7 mRNA expression in NALM-6 and HL-60 cancer cell lines.Methods:HL-60, NALM-6, and normal cells were cultured, and the Decitabine treatment dose was obtained (1 µM) through the MTT assay. Finally, HDAC3 and HDAC7 mRNA expression were measured by Real-Time PCR in HL-60 and NALM-6 cancerous cells before and after treatment. Furthermore, HDAC3 and HDAC7 mRNA expression in untreated HL-60 and NALM-6 cancerous cells were compared to normal cells.Results:Our results revealed that the expression of HDAC3 and HDAC7 in HL-60 and NALM-6 cells increases as compared to normal cells. After treatment of HL-60 and NALM-6 cells with Decitabine, HDAC3, and HDAC7 mRNA expression were decreased significantly.Conclusion:Our data confirmed that the effects of Decitabine are not limited to direct hypomethylation of DNMTs, but it can indirectly affect other epigenetic factors, such as HDACs activity, through converging pathways.Key Words: Decitabine, HDAC3, HDAC7, HL-60, NALM-6     

A Proline-, Threonine-, and Glycine-Rich Protein Down-Regulated by Drought Is Localized in the Cell Wall of Xylem Elements

A cDNA clone encoding a proline-, threonine-, and glycine-rich protein (PTGRP) was isolated from a wild tomato species (Lycopersicon chilense) (L.X. Yu, H. Chamberland, J.G. Lafontain, Z. Tabaeizadeh [1996] Genome 39: 1185-1193). Northern-blot analysis and in situ hybridization studies revealed that PTGRP is down-regulated by drought stress. The level of the mRNA in leaves and stems of 8-d drought-stressed plants decreased 5- to 10-fold compared with that in regularly watered plants. The mRNA re-accumulated when drought-stressed plants were rewatered. Antibodies raised against a glutathione S-transferase/PTGRP fusion protein were used to elucidate the subcellular localization of the protein by immunogold labeling. In regularly watered L. chilense plants, PTGRP protein was found to be localized in xylem pit membranes and disintegrated primary walls. Examination of sections from drought-stressed plants revealed a significant decrease in the levels of labeling. In these samples, only a few scattered gold particles were detected in the same areas. In the leaf tissues of plants that had been rewatered for 3 d following an 8-d drought stress, the labeling pattern was similar to that of the regularly watered plants. To our knowledge, PTGRP is the first drought-regulated protein that has been precisely localized in the cell wall.     

A novel human UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase, GalNAc-T7, with specificity for partial GalNAc-glycosylated acceptor substrates.

A novel member of the human UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase gene family, designated GalNAc-T7, was cloned and expressed. GalNAc-T7 exhibited different properties compared to other characterized members of this gene family, in showing apparent exclusive specificity for partially GalNAc-glycosylated acceptor substrates. GalNAc-T7 showed no activity with a large panel of non-glycosylated peptides, but was selectively activated by partial GalNAc glycosylation of peptide substrates derived from the tandem repeats of human MUC2 and rat submaxillary gland mucin. The function of GalNAc-T7 is suggested to be as a follow-up enzyme in the initiation step of O-glycosylation.