Proposal of \u3cem\u3eVibrionimonas magnilacihabitans\u3c/em\u3e gen. nov., sp. nov., a Curved Gram Negative Bacterium Isolated From Lake Michigan Water

A mesophilic bacterium appearing as curved rod-shaped cells was isolated from Lake Michigan water. It exhibited highest similarities with Sediminibacterium ginsengisoli DCY13T (94.4 %); Sediminibacterium salmoneum NJ-44T (93.6 %) and Hydrotalea flava CCUG 51397 T (93.1 %) while similarities with other recognized species were sym-homospermidine was the primary polyamine. The major cellular fatty acids were iso-C15 : 1G, iso-C15 : 0, iso-C16 : 0 3-OH and iso-C17 : 0 3-OH, with moderate amounts of iso-C16 : 0. The presence of glycolipids differentiated the novel strains from related genera. The DNA mol% G+C content of the type strain MU-2T was 45.2. Results for other phenotypic and molecular analyses indicated that strain MU-2T is a representative of a novel genus and species for which the name Vibrionimonas magnilacihabitans is proposed. The type strain is MU-2T ( = NRRL B-59231 = DSM 22423)

Translational recoding as a feedback controller : systems approaches reveal polyamine-specific effects on the antizyme ribosomal frameshift

Peer reviewedPublisher PD

Potential role of NADPH-oxidase in early steps of lead-induced oxidative burst in Vicia faba roots

The mechanism of oxidative burst induced by lead in Vicia faba excised roots was investigated by luminol-dependent chemiluminescence. Results showed that lead triggered a rapid and dose-dependent increase in chemiluminescence production. In this study, specific inhibitors of putative reactive oxygen species (ROS) sources were used to determine the mechanism of lead-induced ROS generation. This generation was sensitive to dephenylene iodonium (DPI), quinacrine and imidazole, some inhibitors of the NADPH-oxidase and not inhibited by other putative ROS sources inhibitors. Data reported in this work clearly demonstrated the pivotal role of NADPH-oxidase-like enzyme in early steps of lead-induced oxidative burst. To investigate the respective implication of calmodulin and protein kinase (PK) in leadinduced NADPH-oxidase activation, excised roots were treated with the calmodulin inhibitor W7 or with the PK inhibitor staurosporine. The chemiluminescence generation inhibition by these inhibitors illustrated the role of PK in lead-induced NADPH-oxidase activation and revealed a calmodulin-dependent step. Using the calcium entry blocker La 3+ or different concentrations of calcium in the extracellular medium, our data highlighted the implication of Ca 2+ channel in leadinduced oxidative burst

Interaction of plant amine oxidases with diaminoethers

Polyamines are ubiquitous compounds, which are involved in crucial physiological events including cell growth and differentiation. The catabolic oxidative degradation of polyamines is catalyzed by quinoprotein copper-containing amine oxidases (CAOs) and flavoprotein polyamine oxidases (PAOs). Various synthetic polyamine analogs and polyamine derivatives have been reported, which represent important tools (substrates or inhibitors) in the study of catalytic properties of the enzymes. In this work, two related compounds were studied in the reactions with plant amine oxidases: 1,8-diamino-3,6-dioxaoctane (DADO) and 1,10-bis(2- pyridinylmethyl)-4,7-dioxa-1,10-diazadecane (BPDD). Based on activity and stoichiometry assays together with spectrophotometric measurements, DADO can be considered a good substrate for grass pea, lentil and E. characias CAOs with Km values in the range 10-4 – 10-3 M. Its oxidative degradation produces the corresponding aminoaldehyde 8-amino-3,6-dioxaoctanal, which does not undergo spontaneous cyclization (as it is known for the oxidation products of natural substrates putrescine, cadaverine and spermidine) or polymerization in the reaction mixture. Conversely, oat PAO does not oxidize DADO and is only weakly inhibited by the compound (Ki = 1.6 mM towards putrescine). BPDD was found to be a competitive inhibitor of both CAOs and PAOs with Ki values of 10-4 M. DADO could be suggested as a potential affinity ligand for CAOs