Evidence for Arrhythmogenic Effects of A-Adenosine Receptors.

Adenosine can be released from the heart and may stimulate four different cardiac adenosine receptors. A receptor subtype that couples to the generation of cyclic adenosine monophosphate (cAMP) is the A-adenosine receptor (A-AR). To better understand its role in cardiac function, we studied mechanical and electrophysiological effects in transgenic mice that overexpress the human A-AR in cardiomyocytes (A-TG).

Phenotyping of Mice with Heart Specific Overexpression of A-Adenosine Receptors: Evidence for Cardioprotective Effects of A-Adenosine Receptors.

Adenosine can be produced in the heart and acts on cardiac adenosine receptors. One of these receptors is the A-adenosine receptor (A-AR). To better understand its role in cardiac function, we generated and characterized mice (A-TG) which overexpress the human A-AR in cardiomyocytes.

Hyperthermostable acetyl xylan esterase.

An esterase which is encoded within a Thermotoga maritima chromosomal gene cluster for xylan degradation and utilization was characterized after heterologous expression of the corresponding gene in Escherichia coli and purification of the enzyme. The enzyme, designated AxeA, shares amino acid sequence similarity and its broad substrate specificity with the acetyl xylan esterase from Bacillus pumilus, the cephalosporin C deacetylase from Bacillus subtilis, and other (putative) esterases, allowing its classification as a member of carbohydrate esterase family 7. The recombinant enzyme displayed activity with p-nitrophenyl-acetate as well as with various acetylated sugar substrates such as glucose penta-acetate, acetylated oat spelts xylan and DMSO (dimethyl sulfoxide)-extracted beechwood xylan, and with cephalosporin C.