The genomes of intracellur symbionts in deep-sea Calyptogena clams are still in an early phase of reductive genome evolution.

http://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk09-12/ehttp://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk11-04/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt10-08/

A Carbapenem-Resistant Pseudomonas aeruginosa Isolate Harboring Two Copies of blaIMP-34 Encoding a Metallo-β-Lactamase.

A carbapenem-resistant strain of Pseudomonas aeruginosa, NCGM1984, was isolated in 2012 from a hospitalized patient in Japan. Immunochromatographic assay showed that the isolate was positive for IMP-type metallo-β-lactamase. Complete genome sequencing revealed that NCGM1984 harbored two copies of blaIMP-34, located at different sites on the chromosome. Each blaIMP-34 was present in the same structures of the class 1 integrons, tnpA(ISPa7)-intI1-qacG-blaIMP-34-aac(6')-Ib-qacEdelta1-sul1-orf5-tniBdelta-tniA. The isolate belonged to multilocus sequence typing ST235, one of the international high-risk clones. IMP-34, with an amino acid substitution (Glu126Gly) compared with IMP-1, hydrolyzed all β-lactamases tested except aztreonam, and its catalytic activities were similar to IMP-1. This is the first report of a clinical isolate of an IMP-34-producing P. aeruginosa harboring two copies of blaIMP-34 on its chromosome

Heterogeneous composition of key metabolic gene clusters in a vent mussel symbiont population

http://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt07-08/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt10-08/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt11-09/

Biosynthesis of Versipelostatin: Identification of an Enzyme-Catalyzed [4+2]-Cycloaddition Required for Macrocyclization of Spirotetronate-Containing Polyketides

Versipelostatin (VST) is an unusual 17-membered macrocyclic polyketide product that contains a spirotetronate skeleton. In this study, the entire VST biosynthetic gene cluster (<i>vst</i>) spanning 108 kb from <i>Streptomyces versipellis</i> 4083-SVS6 was identified by heterologous expression using a bacterial artificial chromosome vector. Here, we demonstrate that an enzyme, VstJ, catalyzes the stereoselective [4+2]-cycloaddition between the conjugated diene and the exocyclic olefin of a newly identified tetronate-containing intermediate to form the spirotetronate skeleton during VST biosynthesis

Kinetic parameters of the β-lactamases IMP-1 and IMP-34 with various substrates.

<p>Kinetic parameters of the β-lactamases IMP-1 and IMP-34 with various substrates.</p

MICs of β-lactams for <i>P</i>. <i>aeruginosa</i> NCGM1984 and <i>E</i>. <i>coli</i> transformants with <i>bla</i>_IMP-1 and <i>bla</i>_IMP-34.

<p>MICs of β-lactams for <i>P</i>. <i>aeruginosa</i> NCGM1984 and <i>E</i>. <i>coli</i> transformants with <i>bla</i>_IMP-1 and <i>bla</i>_IMP-34.</p

Genomic islands containing class 1 integrons in <i>Pseudomonas aeruginosa</i> NCGM1984.

<p>(A) Genomic island containing integrons A and B. The genomic island was inserted between NCGM1984_2402 (PA2752 in the complete genome of <i>P</i>. <i>aeruginosa</i> PAO1: accession no.AE004091) and NCGM1984_2462 (PA2749). (B) Genomic island containing integron C. The genomic island was inserted between NCGM1984_4147 (PA1181) and NCGM1984_4144 (PA1179). (C) The genomic structure of integrons A and C. The structure of integron A was identical to that of integron C. These integrons contained <i>bla</i>_IMP-34. The red arrow indicates <i>bla</i>_IMP-34. Blue arrows indicate IRi and IRt. Green arrows indicate direct repeats. (D) Genomic structure of integron B. Blue arrows indicate IRi and IRt. Green arrows indicate direct repeats.</p