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Archaea
Volume 1, Issue 4, Pages 277-283
http://dx.doi.org/10.1155/2004/513563
Research Article

A proposal to rename the hyperthermophile Pyrococcus woesei as Pyrococcus furiosus subsp. woesei

1Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD 21202, USA
2IRNAS-CSIC, P.O. Box 1052, 41080 Sevilla, Spain
3Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20274, USA

Received 8 April 2004; Accepted 28 July 2004

Copyright © 2004 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Pyrococcus species are hyperthermophilic members of the order Thermococcales, with optimal growth temperatures approaching 100 °C. All species grow heterotrophically and produce H2 or, in the presence of elemental sulfur (S°), H2S. Pyrococcus woesei and P. furiosus were isolated from marine sediments at the same Vulcano Island beach site and share many morphological and physiological characteristics. We report here that the rDNA operons of these strains have identical sequences, including their intergenic spacer regions and part of the 23S rRNA. Both species grow rapidly and produce H2 in the presence of 0.1% maltose and 10–100 µM sodium tungstate in S°-free medium. However,P. woesei shows more extensive autolysis than P. furiosus in the stationary phase. Pyrococcusfuriosus and P. woesei share three closely related families of insertion sequences (ISs). A Southern blot performed with IS probes showed extensive colinearity between the genomes of P. woesei and P. furiosus. Cloning and sequencing of ISs that were in different contexts in P. woesei and P. furiosus revealed that the napA gene in P. woesei is disrupted by a type III IS element, whereas in P. furiosus, this gene is intact. A type I IS element, closely linked to the napA gene, was observed in the same context in both P. furiosus and P. woesei genomes. Our results suggest that the IS elements are implicated in genomic rearrangements and reshuffling in these closely related strains. We propose to rename P. woesei a subspecies of P. furiosus based on their identical rDNA operon sequences, many common IS elements that are shared genomic markers, and the observation that all P. woesei nucleotide sequences deposited in GenBank to date are > 99% identical to P. furiosus sequences.