ABSTRACT
A novel polyoxometalate-cation exchanger, titanium(IV) molybdophosphate (TMP) has been synthesized under varying conditions. The material was characterized by X-ray diffraction, infrared spectroscopy, inductively coupled plasma and thermogravimetry techniques. Its stability was investigated in water, dilute acids, alkaline solutions, and high temperature up to 750 degrees C. Ion-exchange capacity and distribution coefficients (K(d)) for twenty-nine radionuclides and metal ions have been determined. It was found that the TMP has high affinity for Cs(+), Sr(2+), UO(2)(2+), Ba(2+), Pb(2+), Tl(+), Zn(2+), Rb(2+) and Zr(4+) ions. The results of binary separation of metal ions showed that TMP can be potentially useful for analytical applications.
ABSTRACT
The development of the sympathetic nervous system involves cell-cell interactions that regulate the fate and migration of progenitor neural cells. Recent evidence shows that focal membrane-bound protease activity is critical for such interactions. The Drosophila kuzbanian (kuz) gene is required in neurogenesis and encodes a highly conserved, membrane-bound metalloprotease- disintegrin closley related to theTNF-alphaconvertingenzyme (TACE). We have characterized the human and mouse kuz homologs and mapped human kuz to chromosome 15q22. During mouse embryonic development Kuz is expressed mainly in the sympathoadrenal and olfactory neural precursors. Once sympathoadrenal cells differentiate into chromaffin cells in the adult adrenal medulla, they no longer express Kuz. However, we found that tumors of sympathoadrenal origin, such as pheochromocytomas and neuroblastomas, overexpress Kuz. Further, transfection of a kuz construct lacking the protease domain, but not the full-length construct, induces neurite formation in PC12 chromaffin tumor cells. Taken together our results suggest a critical role for Kuz in regulation of sympathoadrenal cell fate.
Subject(s)
Adrenal Medulla/growth & development , Disintegrins/genetics , Drosophila Proteins , Gene Expression Regulation, Developmental , Gene Expression Regulation, Neoplastic , Metalloendopeptidases/genetics , Sympathetic Nervous System/growth & development , Adrenal Medulla/cytology , Adrenal Medulla/enzymology , Amino Acid Sequence , Animals , Chromosome Mapping , Chromosomes, Human, Pair 12/genetics , Cloning, Molecular , Humans , Mice , Molecular Sequence Data , Sympathetic Nervous System/cytology , Sympathetic Nervous System/enzymologyABSTRACT
To assess regulation of constitutive prostaglandin G/H synthase (PGHS-1) by interleukin-1 (IL-1) in osteoblastic MC3T3-E1 cells, we compared analysis by competitive reverse transcriptase-polymerase chain reaction (RT-PCR) with Northern blot analysis. Using RT-PCR, IL-1 increased PGHS-1 mRNA levels by 1.84 +/- 0.10 or 2.07 +/- 0.17, depending on the method of calculation. Using Northern blot analysis, the effect of IL-1 on PGHS-1 mRNA levels was more variable, and the variability was increased by normalization of PGHS-1 mRNA levels to the housekeeping genes, beta-actin and glyceraldehyde phosphate dehydrogenase (GAPDH), because their mRNA levels were also regulated by IL-1. We conclude that competitive RT-PCR is a reproducible and accurate method for studying small changes in mRNA levels.
