Immobilization of heparin with trichloro-s-triazine: Purification of mouse antithrombin

A method for covalently attaching heparin to agarose in which the bound heparin is resistant to detachment is described. A controlled amount of 4-aminophenethylamine is linked to trichloro-s-triazine-activated agarose via the primary amino group. The resulting immobilized arylamine is then diazo coupled to an appropriately modified heparin. The immobilized heparin was used in a two-step procedure for the purification of mouse antithrombin. Some of the properties of the mouse antithrombin are described.     

Epigenetic regulation in human melanoma: past and future

The development and progression of melanoma have been attributed to independent or combined genetic and epigenetic events. There has been remarkable progress in understanding melanoma pathogenesis in terms of genetic alterations. However, recent studies have revealed a complex involvement of epigenetic mechanisms in the regulation of gene expression, including methylation, chromatin modification and remodeling, and the diverse activities of non-coding RNAs. The roles of gene methylation and miRNAs have been relatively well studied in melanoma, but other studies have shown that changes in chromatin status and in the differential expression of long non-coding RNAs can lead to altered regulation of key genes. Taken together, they affect the functioning of signaling pathways that influence each other, intersect, and form networks in which local perturbations disturb the activity of the whole system. Here, we focus on how epigenetic events intertwine with these pathways and contribute to the molecular pathogenesis of melanoma.     

Nickel accumulation by immobilized biofilm of Cirobacter sp. containing cell-bound polycrystalline hydrogen uranyl phosphate

Hydrogen uranyl phosphate (HUO2PO4: HUP), deposited enzymatically on Citrobacter N14 cells immobilized as biofilm on ceramic Raschig rings in a flow-through column, removed nickel quantitatively from dilute aqueous solution in the form of nickel uranyl phosphate, via intercalative ion exchange. Nickel-loaded columns were regenerated by washing either with citrate buffer or with buffer containing UO22 and phosphate donor (glycerol 2-phosphate), this giving additional crystalline HUP deposit for subsequent improvement of nickel removal. No uranium release occurred during selective desorption of Ni, proving the integrity of the biofilm within the column. The use of ceramic supports to manufacture an artificial, bioinorganic, ion exchanger is novel and the use of solid matrices overcomes the problems of mechanical stability which limit the applications of gel-immobilized cells for large-scale processes. © Rapid Science Ltd. 1998     

Hydrogenosomes in some anaerobic protozoa resemble mitochondria

Abstract Microbodies in six anaerobic ciliated protozoa ( Metopus, Brachonella, Plagiopyla, Parablepharisma, Sonderia, Saprodinium ) were found to be enclosed by two membranes. The inner membrane showed extensive infolding, division stages were observed, and in all genera apart from Sonderia and Parablepharisma , the microbodies contained an hydrogenase and were attached to methanogenic bacteria. Some of these ciliates are related to aerobic species with mitochondria. We believe that the microbodies are hydrogenosomes, that they are derived from mitochondria, and that their biochemical modification has incurred little change in the original mitochondrial ultrastructure. These observations weaken the case for the independent origin of hydrogenosomes from anaerobic prokaryotes.