Golgi localization of glycosyltransferases involved in ganglioside biosynthesis.

Gangliosides make up a group of sialic acid-containing complex glycosphingolipids particularly abundant in the central nervous system. The finding indicating gangliosides are stored in certain hereditary diseases affecting the central nervous system opened the interest in studying their metabolism. The initial in vitro pioneering work on the glycosyltransferases involved in ganglioside biosynthesis was done by Roseman and his associates primarily in embryonic chick brains almost forty years ago.

An RNA molecule that specifically inhibits G-protein-coupled receptor kinase 2 in vitro.

G-protein-coupled receptors are desensitized by a two-step process. In a first step, G-protein-coupled receptor kinases (GRKs) phosphorylate agonist-activated receptors that subsequently bind to a second class of proteins, the arrestins. GRKs can be classified into three subfamilies, which have been implicated in various diseases.

Secondary structures and functional requirements for thiM riboswitches from Desulfovibrio vulgaris, Erwinia carotovora and Rhodobacter spheroides.

Abstract Bacterial thiM riboswitches contain aptamer domains that bind the metabolite thiamine pyrophosphate (TPP). Binding of TPP to the aptamer domain induces structural rearrangements that are relayed to the expression domain, thereby interfering with gene expression. Here, we report identification of three putative thiM riboswitches from different bacteria and analysis of their secondary structures.

Anti-innexin 2 aptamers specifically inhibit the heterologous interaction of the innexin 2 and innexin 3 carboxyl-termini in vitro.

We recently demonstrated that heteromerization of innexins 2 and 3 from Drosophila melanogaster (Dm) is crucial for epithelial organization and polarity of the embryonic epidermis. Both innexins are thought to interact via their C-terminal cytoplasmic domains during the assembly of heteromeric gap junction channels. However, the mechanisms that control heteromeric versus homomeric channel formation are still largely unknown.

Effects of sphingosine-1-phosphate and ceramide-1-phosphate on rat intestinal smooth muscle cells: implications for postoperative ileus.

Postoperative ileus, a major cause of morbidity after abdominal surgery, is characterized by intestinal dysmotility and inflammation. The aim was to investigate the involvement of sphingolipids in postoperative intestinal inflammation using a standardized rat model of intestinal surgical manipulation. Sphingolipid analysis (ESI-MS) of intestinal muscularis after manipulation revealed a time-dependent increase of sphingosine 1-phosphate (S1P) and of ceramide 1-phosphate (C1P).

Sphingolipid metabolism in neural cells.

Sphingolipids were discovered more than a century ago in the brain. Cerebrosides and sphingomyelins were named so because they were first isolated from neural tissue. Although glycosphingolipids and especially those containing sialic acid in their oligosaccharide moiety are particularly abundant in the brain, sphingolipids are ubiquitous cellular membrane components.

Discrimination of single mutations in cancer-related gene fragments with a surface acoustic wave sensor.

Here, we report on using a surface acoustic wave sensor for the highly sensitive and accurate detection of individual point mutations in cancer-related gene DNA fragments from single injections. Our sensor measures both the mass and viscosity signals and, thus, allows discriminating between mass effects resulting from hybridization of short DNA strands and viscosity effects due to increasing amounts of DNA deposited on the sensor. Single nucleotide exchanges or deletions are distinguished reliably and with exceeding simplicity from the wild-type sequences, on the basis of differences in their dissociation or association rates starting at low nanomolar concentrations.

Light regulation of aptamer activity: an anti-thrombin aptamer with caged thymidine nucleobases.

"Caged" derivatives of a 15 nucleotide ssDNA anti-thrombin aptamer have been synthesized in which thymidine nucleotides are modified with photolabile protecting groups. One caged thymidine in a key location is enough to completely mask the aptamer's function in respect to their affinity for thrombin and their inhibition of the blood clotting cascade. With light (366 nm) the caging group can be removed, yielding the unmodified active aptamer.

Degradation of membrane-bound ganglioside GM1. Stimulation by bis(monoacylglycero)phosphate and the activator proteins SAP-B and GM2-AP.

According to our hypothesis (Fürst, W., and Sandhoff, K. (1992) Biochim.