Molecular genetics and biochemistry of N-acetyltaurine degradation by Cupriavidus necator H16.

Cupriavidus necator H16 (DSM 428), whose genome has been sequenced, was found to degrade N-acetyltaurine as a sole source of carbon and energy for growth. Utilization of the compound was quantitative. The degradative pathway involved an inducible N-acetyltaurine amidohydrolase (NaaS), which catalysed the cleavage of N-acetyltaurine to acetate and taurine. The degradation of the latter compound is via an inducible, degradative pathway that involves taurine dehydrogenase [EC 1.4.2.-], sulfoacetaldehyde acetyltransferase [EC 2.3.3.15], phosphotransacetylase [EC 2.4.1.8], a sulfite exporter [TC 9.A.29.2.1] and sulfite dehydrogenase [EC 1.8.2.1]. Induction of the expression of representative gene products, encoded by at least four gene clusters, was confirmed biochemically. The acetate released by NaaS was activated to acetyl-CoA by an inducible acetate-CoA ligase [EC 6.2.1.1]. NaaS was purified to homogeneity; it had a K(m) value of 9.4 mM for N-acetyltaurine, and it contained tightly bound Zn and Fe atoms. The denatured enzyme has a molecular mass of about 61 kDa (determined by SDS-PAGE) and the native enzyme was apparently monomeric. Peptide-mass fingerprinting identified the locus tag as H16_B0868 in a five-gene cluster, naaROPST (H16_B0865-H16_B0869). The cluster presumably encodes a LysR-type transcriptional regulator (NaaR), a membrane protein (NaaO), a solute : sodium symporter-family permease [TC 2.A.21] (NaaP), the metal-dependent amidohydrolase (NaaS) and a putative metallochaperone (COG0523) (NaaT). Reverse-transcription PCR indicated that naaOPST were inducibly transcribed.

Characterization of cerebrospinal fluid aminoterminally truncated and oxidized amyloid-ß peptides.

PURPOSE: Carboxyterminally elongated and aminoterminally truncated Aß peptides as well as their pyroglutamate and oxidized derivates are major constituents of human amyloid plaques. The objective of the present study was to characterize aminoterminally truncated or oxidized Aß38, Aß40, and Aß42 peptide species in immunoprecipitated human cerebrospinal fluid (CSF). EXPERIMENTAL DESIGN: We invented a novel sequential aminoterminally and carboxyterminally specific immunoprecipitation protocol and used the Aß-SDS-PAGE/immunoblot for subsequent analysis of CSF Aß peptide patterns. RESULTS: In the present study, we identified the aminoterminally truncated Aß peptides 2-40 and 2-42 as well as oxidized forms of Aß1-38 and Aß1-42 in CSF. Our protocol allowed the quantification of a pattern of Aß peptides 1-38(ox), 2-40, and 2-42 in addition to the well known panel of Aß 1-37, 1-38, 1-39, 1-40, 1-40(ox), and 1-42 in a group of seven patients with peripheral polyneuropathy. CONCLUSIONS AND CLINICAL RELEVANCE: In the present approach, we could broaden the range of quantifiable Aß peptides described in previous studies (i.e., 1-37, 1-38, 1-39, 1-40, 1-40(ox), and 1-42) by Aß 1-38(ox), 2-40, and 2-42. An exact analysis of CSF Aß peptides regarding their carboxy- and aminoterminus as well as posttranslational modification seems promising with respect to diagnostic and pathogenic aspects.

Standard preanalytical coding for biospecimens: review and implementation of the Sample PREanalytical Code (SPREC).

The first version of the Standard PREanalytical Code (SPREC) was developed in 2009 by the International Society for Biological and Environmental Repositories (ISBER) Biospecimen Science Working Group to facilitate documentation and communication of the most important preanalytical quality parameters of different types of biospecimens used for research. This same Working Group has now updated the SPREC to version 2.0, presented here, so that it contains more options to allow for recent technological developments. Existing elements have been fine tuned. An interface to the Biospecimen Reporting for Improved Study Quality (BRISQ) has been defined, and informatics solutions for SPREC implementation have been developed. A glossary with SPREC-related definitions has also been added.