A novel gamma-N-methylaminobutyrate demethylating oxidase involved in catabolism of the tobacco alkaloid nicotine by Arthrobacter nicotinovorans pAO1.

Nicotine catabolism, linked in Arthrobacter nicotinovorans to the presence of the megaplasmid pAO1, leads to the formation of gamma-N-methylaminobutyrate from the pyrrolidine ring of the alkaloid. Until now the metabolic fate of gamma-N-methylaminobutyrate has been unknown. pAO1 carries a cluster of ORFs with similarity to sarcosine and dimethylglycine dehydrogenases and oxidases, to the bifunctional enzyme methylenetetrahydrofolate dehydrogenase/cyclohydrolase and to formyltetrahydrofolate deformylase. We cloned and expressed the gene carrying the sarcosine dehydrogenase-like ORF and showed, by enzyme activity, spectrophotometric methods and identification of the reaction product as gamma-aminobutyrate, that the predicted 89 395 Da flavoprotein is a demethylating gamma-N-methylaminobutyrate oxidase. Site-directed mutagenesis identified His67 as the site of covalent attachment of FAD and confirmed Trp66 as essential for FAD binding, for enzyme activity and for the spectral properties of the wild-type enzyme. A Km of 140 microm and a kcat of 800 s(-1) was determined when gamma-N-methylaminobutyrate was used as the substrate. Sarcosine was also turned over by the enzyme, but at a rate 200-fold slower than gamma-N-methylaminobutyrate. This novel enzyme activity revealed that the first step in channelling the gamma-N-methylaminobutyrate generated from nicotine into the cell metabolism proceeds by its oxidative demethylation.     

Trends in lizard translocations in New Zealand between 1988 and 2013

There is growing concern about mitigation-driven translocations that move animals from anthropogenic threats at donor sites because of their failure rate and lack of application of scientific principles and best practice. We reviewed all known lizard translocations in New Zealand between 1988 and 2013 and identified 85 translocations of 30 lizard taxa to 46 release sites. Most translocations (62%) were motivated by conservation goals for the species or the release site, and one-third were mitigation-driven translocations, typically motivated by habitat loss due to development. Mitigation-driven translocations began in 2003, and since that time have equalled the number of conservation-motivated translocations. Conservation-motivated translocations usually released lizards on islands without mammalian predators, whereas mitigation-driven translocations usually relocated lizards to mainland sites with introduced predators. Long-term monitoring has been sparse and often rudimentary. Eight lizard translocations have recorded population growth, including one mitigation-driven translocation that was into a fenced reserve. Research on commonly used management techniques to mitigate human-related impacts is recommended to establish whether these techniques benefit lizards in the long term.     

Hmgi-c-independent Activation of MuRantes in Vivo.

The architectural factor HMGI-C is of considerable interest for its recognized roles in mammalian development and tumorigenesis. As a result, the identification of downstream target genes of HMGI-C is the present focus of active research. In vitro evidence from macrophage cell lines has previously suggested that Hmgi-c is necessary for the inducible activation of MuRantes expression. To attempt to verify this hypothesis, an in vivo analysis was performed that took advantage of the existence of the Hmgi-c null mouse strain. The ability of cells and tissues extracted from Hmgi-c null mice to express the inflammatory chemokine MuRantes was investigated. The investigation examined MuRantes expression in primary embryonic fibroblasts and fresh peritoneal macrophages after Newcastle disease virus induction and whole organs after lipopolysaccharide induction. Each of these systems clearly demonstrates that Hmgi-c is not required for the activation of MuRantes expression.     

Food-associated cues alter forebrain functional connectivity as assessed with immediate early gene and proenkephalin expression

Background  

Cues predictive of food availability are powerful modulators of appetite as well as food-seeking and ingestive behaviors. The neurobiological underpinnings of these conditioned responses are not well understood. Monitoring regional immediate early gene expression is a method used to assess alterations in neuronal metabolism resulting from upstream intracellular and extracellular signaling. Furthermore, assessing the expression of multiple immediate early genes offers a window onto the possible sequelae of exposure to food cues, since the function of each gene differs. We used immediate early gene and proenkephalin expression as a means of assessing food cue-elicited regional activation and alterations in functional connectivity within the forebrain.