Metabolic and evolutionary relationships among Pyrococcus Species: genetic exchange within a hydrothermal vent environment.
Pyrococcus furiosus and Pyrococcus woesei grow optimally at temperatures near 100 degrees C and were isolated from the same shallow marine volcanic vent system. Hybridization of genomic DNA from P. woesei to a DNA microarray containing all 2,065 open reading frames (ORFs) annotated in the P. furiosus genome, in combination with PCR analysis, indicated that homologs of 105 ORFs present in P. furiosus are absent from the uncharacterized genome of P. woesei. Pulsed-field electrophoresis indicated that the sizes of the two genomes are comparable, and the results were consistent with the hypothesis that P. woesei lacks the 105 ORFs found in P. furiosus. The missing ORFs are present in P. furiosus mainly in clusters. These clusters include one cluster (Mal I, PF1737 to PF1751) involved in maltose metabolism and another cluster (PF0691 to PF0695) whose products are thought to remove toxic reactive nitrogen species. Accordingly, it was found that P. woesei, in contrast to P. furiosus, is unable to utilize maltose as a carbon source for growth, and the growth of P. woesei on starch was inhibited by addition of a nitric oxide generator. In P. furiosus the ORF clusters not present in P. woesei are bracketed by or are in the vicinity of insertion sequences or long clusters of tandem repeats (LCTRs). While the role of LCTRs in lateral gene transfer is not known, the Mal I cluster in P. furiosus is a composite transposon that undergoes replicative transposition. The same locus in P. woesei lacks any evidence of insertion activity, indicating that P. woesei is a sister or even the parent of P. furiosus. P. woesei may have acquired by lateral gene transfer more than 100 ORFs from other organisms living in the same thermophilic environment to produce the type strain of P. furiosus.
Hamilton-Brehm
Scott D
SD
Department of Biochemistry and Molecular Biology, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602-7229, USA.
Schut
Gerrit J
GJ
Adams
Michael W W
MW
D004251:DNA Transposable Elements; D019641:DNA, Archaeal / Q000302:isolation & purification; D016521:Electrophoresis, Gel, Pulsed-Field; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D019766:Genes, Archaeal; D045482:Hot Springs / Q000382:microbiology*; D008320:Maltose / Q000378:metabolism; D008660:Metabolism / Q000235:genetics; D005810:Multigene Family; D009569:Nitric Oxide / Q000633:toxicity; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D016366:Open Reading Frames; D019711:Pyrococcus / Q000235:genetics* / Q000378:metabolism*; D020080:Tandem Repeat Sequences; D014871:Water Microbiology
D004251:DNA Transposable Elements; D019641:DNA, Archaeal; D009569:Nitric Oxide; D008320:Maltose