Reference

The Putative Malate/Lactate Dehydrogenase from Pseudomonas putida Is an NADPH-dependent D1-Piperidine-2-carboxylate/D1-Pyrroline-2-carboxylate Reductase Involved in the Catabolism of D-Lysine and D-Proline

The Putative Malate/Lactate Dehydrogenase from Pseudomonas putida Is an NADPH-dependent D1-Piperidine-2-carboxylate/D1-Pyrroline-2-carboxylate Reductase Involved in the Catabolism of D-Lysine and D-Proline. Muramatsu, Hisashi; Mihara, Hisaaki; Kakutani, Ryo; Yasuda, Mari; Ueda, Makoto; Kurihara, Tatsuo; Esaki, Nobuyoshi (Institute for Chemical Research, Kyoto Univ., Kyoto 611-0011, Japan). Journal of Biological Chemistry, 280(7), 5329-5335 (English) 2005 American Society for Biochemistry and Molecular Biology. CODEN: JBCHA3. ISSN: 0021-9258. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) A Pseudomonas putida ATCC12633 gene, dpkA, encoding a putative protein annotated as malate/L-lactate dehydrogenase in various sequence data bases was disrupted by homologous recombination. The resultant dpkA- mutant was deprived of the ability to use D-lysine and also D-proline as a sole carbon source. The dpkA gene was cloned and overexpressed in Escherichia coli, and the gene product was characterized. The enzyme showed neither malate dehydrogenase nor lactate dehydrogenase activity but catalyzed the NADPH-dependent redn. of such cyclic imines as D1-piperidine-2-carboxylate and D1-pyrroline-2-carboxylate to form L-pipecolate and L-proline, resp. NADH also served as a hydrogen donor for both substrates, although the reaction rates were less than 1% of those with NADPH. The reverse reactions were also catalyzed by the enzyme but at much lower rates. Thus, the enzyme has dual metabolic functions, and we named the enzyme D1-piperidine-2-carboxylate/D1-pyrroline-2-carboxylate reductase, the first member of a novel subclass in a large family of NAD(P)-dependent oxidoreductases.

Surface modification and neural tissue culture of thin film electrode materials

Surface modification and neural tissue culture of thin film electrode materials. Thanawala, Sachin; Khan, Saida P.; Palyvoda, Olena; Georgiev, Daniel G.; Al-Homoudi, Ibrahim A.; Newaz, Golam; Auner, Gregory ( Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA). Materials Research Society Symposium Proceedings, 872(Micro- and Nanosystems--Materials and Devices), 359-364 (English) 2005 Materials Research Society. CODEN: MRSPDH. ISSN: 0272-9172. DOCUMENT TYPE: Journal CA Section: 9 (Biochemical Methods) Section cross-reference(s): 63 Good interfaces between electrodes and neural tissue are very important in chronic in vivo stimulation/recording. To study the effect of electrode materials and surface structure on neural interfaces, the authors cultured neurons on thin films of electrode materials that are expected to be biocompatible, such as platinum, and iridium oxide. The authors used both flat film surfaces and laser micro-structured ones. The laser micro-structuring consisted of creating regular arrays of micro-bumps with height of about 1mm and diam. of 2-3 m. The authors have found conditions for fabrication of such micro-bumps on platinum and iridium thin films on borosilicate glass substrate (Pyrex 7740) by mask-projection irradn. with single nano-second pulses from a KrF excimer laser (l = 248 nm). Laser micro-structured iridium films were coated with IrO2 by pulsed DC reactive sputtering to obtain micro-structured IrO2 films.Several reagents with their cas registry numbers 12030-49-8 and 7439-88-5 are used here. Two types of iridium oxide films were studied: amorphous (reactively sputtered at room substrate temp.) and polycryst. (reactively sputtered at 300°). Cortical neurons isolated from rat embryo brain were cultured onto these thin film surfaces. Cells were more than 98% viable as detd. by trypan blue exclusion tests. Poly-D-Lysine coated surfaces were used as pos. controls for cell. Regular optical and fluorescent microscopy techniques were used to image the cells after they were cultured. To differentiate between live and dead cells a viability test with fluorescein diacetate (FDA) and propidium iodide was carried out. Also, immunocytochem. anal. of neuron cells was performed using antibody for neuron-specific enolase (NSE) staining. A qual. and quant. comparison was carried out between the different types of modified electrode surfaces to study the neuronal growth to explore the feasibility of micro-bumps as stimulating/recording neural interfaces. These results are intended for use in optimization of future elec. stimulation/recording expts. that the authors plan to carry out. .