Isosphaera pallida (ex Woronichin 1927) Giovannoni et al. 1995 is the type species of the genus Isosphaera. The species is of interest because it was the first heterotrophic bacterium known to be phototactic, and it occupies an isolated phylogenetic position within the Planctomycetaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of a member of the genus Isosphaera and the third of a member of the family Planctomycetaceae. The 5,472,964 bp long chromosome and the 56,340 bp long plasmid with a total of 3,763 protein-coding and 60 RNA genes are part of the Genomic Encyclopedia of Bacteria and Archaea project.
Marivirga tractuosa (Lewin 1969) Nedashkovskaya et al. 2010 is the type species of the genus Marivirga, which belongs to the family Flammeovirgaceae. Members of this genus are of interest because of their gliding motility. The species is of interest because representative strains show resistance to several antibiotics, including gentamicin, kanamycin, neomycin, polymixin and streptomycin. This is the first complete genome sequence of a member of the family Flammeovirgaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 4,511,574 bp long chromosome and the 4,916 bp plasmid with their 3,808 protein-coding and 49 RNA genes are a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Zymomonas mobilis ATCC 10988 is the type strain of the Z. mobilis subsp. mobilis taxon, members of which are some of the most rigorous ethanol-producing bacteria. Isolated from Agave cactus fermentations in Mexico, ATCC 10988 is one of the first Z. mobilis strains to be described and studied. Its robustness in sucrose-substrate fermentations, physiological characteristics, large number of plasmids, and overall genomic plasticity render this strain important to the study of the species. Here we report the finishing and annotation of the ATCC 10988 chromosomal and plasmid genome.
Parvibaculum lavamentivorans DS-1(T) is the type species of the novel genus Parvibaculum in the novel family Rhodobiaceae (formerly Phyllobacteriaceae) of the order Rhizobiales of Alphaproteobacteria. Strain DS-1(T) is a non-pigmented, aerobic, heterotrophic bacterium and represents the first tier member of environmentally important bacterial communities that catalyze the complete degradation of synthetic laundry surfactants. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,914,745 bp long genome with its predicted 3,654 protein coding genes is the first completed genome sequence of the genus Parvibaculum, and the first genome sequence of a representative of the family Rhodobiaceae.
Acidaminococcus fermentans (Rogosa 1969) is the type species of the genus Acidaminococcus, and is of phylogenetic interest because of its isolated placement in a genomically little characterized region of the Firmicutes. A. fermentans is known for its habitation of the gastrointestinal tract and its ability to oxidize trans-aconitate. Its anaerobic fermentation of glutamate has been intensively studied and will now be complemented by the genomic basis. The strain described in this report is a nonsporulating, nonmotile, Gram-negative coccus, originally isolated from a pig alimentary tract. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the family Acidaminococcaceae, and the 2,329,769 bp long genome with its 2,101 protein-coding and 81 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Chitinophaga pinensis Sangkhobol and Skerman 1981 is the type strain of the species which is the type species of the rapidly growing genus Chitinophaga in the sphingobacterial family 'Chitinophagaceae'. Members of the genus Chitinophaga vary in shape between filaments and spherical bodies without the production of a fruiting body, produce myxospores, and are of special interest for their ability to degrade chitin. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the family 'Chitinophagaceae', and the 9,127,347 bp long single replicon genome with its 7,397 protein-coding and 95 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Whether Vibrio mimicus is a variant of Vibrio cholerae or a separate species has been the subject of taxonomic controversy. A genomic analysis was undertaken to resolve the issue. The genomes of V. mimicus MB451, a clinical isolate, and VM223, an environmental isolate, comprise ca. 4,347,971 and 4,313,453 bp and encode 3,802 and 3,290 ORFs, respectively. As in other vibrios, chromosome I (C-I) predominantly contains genes necessary for growth and viability, whereas chromosome II (C-II) bears genes for adaptation to environmental change. C-I harbors many virulence genes, including some not previously reported in V. mimicus, such as mannose-sensitive hemagglutinin (MSHA), and enterotoxigenic hemolysin (HlyA); C-II encodes a variant of Vibrio pathogenicity island 2 (VPI-2), and Vibrio seventh pandemic island II (VSP-II) cluster of genes. Extensive genomic rearrangement in C-II indicates it is a hot spot for evolution and genesis of speciation for the genus Vibrio. The number of virulence regions discovered in this study (VSP-II, MSHA, HlyA, type IV pilin, PilE, and integron integrase, IntI4) with no notable difference in potential virulence genes between clinical and environmental strains suggests these genes also may play a role in the environment and that pathogenic strains may arise in the environment. Significant genome synteny with prototypic pre-seventh pandemic strains of V. cholerae was observed, and the results of phylogenetic analysis support the hypothesis that, in the course of evolution, V. mimicus and V. cholerae diverged from a common ancestor with a prototypic sixth pandemic genomic backbone.
Haliangium ochraceum Fudou et al. 2002 is the type species of the genus Haliangium in the myxococcal family 'Haliangiaceae'. Members of the genus Haliangium are the first halophilic myxobacterial taxa described. The cells of the species follow a multicellular lifestyle in highly organized biofilms, called swarms, they decompose bacterial and yeast cells as most myxobacteria do. The fruiting bodies contain particularly small coccoid myxospores. H. ochraceum encodes the first actin homologue identified in a bacterial genome. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the myxococcal suborder Nannocystineae, and the 9,446,314 bp long single replicon genome with its 6,898 protein-coding and 53 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Gordonia bronchialis Tsukamura 1971 is the type species of the genus. G. bronchialis is a human-pathogenic organism that has been isolated from a large variety of human tissues. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of the family Gordoniaceae. The 5,290,012 bp long genome with its 4,944 protein-coding and 55 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Pollutants such as polychlorinated biphenyls and dioxins pose a serious threat to human and environmental health. Natural attenuation of these compounds by microorganisms provides one promising avenue for their removal from contaminated areas. Over the past 2 decades, studies of the bacterium Sphingomonas wittichii RW1 have provided a wealth of knowledge about how bacteria metabolize chlorinated aromatic hydrocarbons. Here we describe the finished genome sequence of S. wittichii RW1 and major findings from its annotation.
Haloterrigena turkmenica (Zvyagintseva and Tarasov 1987) Ventosa et al. 1999, comb. nov. is the type species of the genus Haloterrigena in the euryarchaeal family Halobacteriaceae. It is of phylogenetic interest because of the yet unclear position of the genera Haloterrigena and Natrinema within the Halobacteriaceae, which created some taxonomic problems historically. H. turkmenica, was isolated from sulfate saline soil in Turkmenistan, is a relatively fast growing, chemoorganotrophic, carotenoid-containing, extreme halophile, requiring at least 2 M NaCl for growth. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of the genus Haloterrigena, but the eighth genome sequence from a member of the family Halobacteriaceae. The 5,440,782 bp genome (including six plasmids) with its 5,287 protein-coding and 63 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Archaeoglobus profundus (Burggraf et al. 1990) is a hyperthermophilic archaeon in the euryarchaeal class Archaeoglobi, which is currently represented by the single family Archaeoglobaceae, containing six validly named species and two strains ascribed to the genus 'Geoglobus' which is taxonomically challenged as the corresponding type species has no validly published name. All members were isolated from marine hydrothermal habitats and are obligate anaerobes. Here we describe the features of the organism, together with the complete genome sequence and annotation. This is the second completed genome sequence of a member of the class Archaeoglobi. The 1,563,423 bp genome with its 1,858 protein-coding and 52 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Methanoculleus marisnigri Romesser et al. 1981 is a methanogen belonging to the order Methanomicrobiales within the archaeal phylum Euryarchaeota. The type strain, JR1, was isolated from anoxic sediments of the Black Sea. M. marisnigri is of phylogenetic interest because at the time the sequencing project began only one genome had previously been sequenced from the order Methanomicrobiales. We report here the complete genome sequence of M. marisnigri type strain JR1 and its annotation. This is part of a Joint Genome Institute 2006 Community Sequencing Program to sequence genomes of diverse Archaea.
Vibrio cholerae, the causative agent of cholera, is a bacterium autochthonous to the aquatic environment, and a serious public health threat. V. cholerae serogroup O1 is responsible for the previous two cholera pandemics, in which classical and El Tor biotypes were dominant in the sixth and the current seventh pandemics, respectively. Cholera researchers continually face newly emerging and reemerging pathogenic clones carrying diverse combinations of phenotypic and genotypic properties, which significantly hampered control of the disease. To elucidate evolutionary mechanisms governing genetic diversity of pandemic V. cholerae, we compared the genome sequences of 23 V. cholerae strains isolated from a variety of sources over the past 98 years. The genome-based phylogeny revealed 12 distinct V. cholerae lineages, of which one comprises both O1 classical and El Tor biotypes. All seventh pandemic clones share nearly identical gene content. Using analogy to influenza virology, we define the transition from sixth to seventh pandemic strains as a "shift" between pathogenic clones belonging to the same O1 serogroup, but from significantly different phyletic lineages. In contrast, transition among clones during the present pandemic period is characterized as a "drift" between clones, differentiated mainly by varying composition of laterally transferred genomic islands, resulting in emergence of variants, exemplified by V. cholerae O139 and V. cholerae O1 El Tor hybrid clones. Based on the comparative genomics it is concluded that V. cholerae undergoes extensive genetic recombination via lateral gene transfer, and, therefore, genome assortment, not serogroup, should be used to define pathogenic V. cholerae clones.
Kangiella koreensis (Yoon et al. 2004) is the type species of the genus and is of phylogenetic interest because of the very isolated location of the genus Kangiella in the gammaproteobacterial order Oceanospirillales. K. koreensis SW-125(T) is a Gram-negative, non-motile, non-spore-forming bacterium isolated from tidal flat sediments at Daepo Beach, Yellow Sea, Korea. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first completed genome sequence from the genus Kangiella and only the fourth genome from the order Oceanospirillales. This 2,852,073 bp long single replicon genome with its 2647 protein-coding and 48 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Pedobacter heparinus (Payza and Korn 1956) Steyn et al. 1998 comb. nov. is the type species of the rapidly growing genus Pedobacter within the family Sphingobacteriaceae of the phylum 'Bacteroidetes'. P. heparinus is of interest, because it was the first isolated strain shown to grow with heparin as sole carbon and nitrogen source and because it produces several enzymes involved in the degradation of mucopolysaccharides. All available data about this species are based on a sole strain that was isolated from dry soil. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first report on a complete genome sequence of a member of the genus Pedobacter, and the 5,167,383 bp long single replicon genome with its 4287 protein-coding and 54 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Leptotrichia buccalis (Robin 1853) Trevisan 1879 is the type species of the genus, and is of phylogenetic interest because of its isolated location in the sparsely populated and neither taxonomically nor genomically adequately accessed family 'Leptotrichiaceae' within the phylum 'Fusobacteria'. Species of Leptotrichia are large, fusiform, non-motile, non-sporulating rods, which often populate the human oral flora. L. buccalis is anaerobic to aerotolerant, and saccharolytic. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of the order 'Fusobacteriales' and no more than the second sequence from the phylum 'Fusobacteria'. The 2,465,610 bp long single replicon genome with its 2306 protein-coding and 61 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Zymomonas mobilis is an ethanol-producing alphaproteobacterium currently considered a major candidate organism for bioethanol production. Here we report the finished and annotated genome sequence of Z. mobilis subsp. mobilis strain NCIMB 11163, a British ale-infecting isolate. This is the first Z. mobilis strain whose genome, chromosomal and plasmid, is presented in its entirety.
Anaerococcus prevotii (Foubert and Douglas 1948) Ezaki et al. 2001 is the type species of the genus, and is of phylogenetic interest because of its arguable assignment to the provisionally arranged family 'Peptostreptococcaceae'. A. prevotii is an obligate anaerobic coccus, usually arranged in clumps or tetrads. The strain, whose genome is described here, was originally isolated from human plasma; other strains of the species were also isolated from clinical specimen. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a member of the genus. Next to Finegoldia magna, A. prevotii is only the second species from the family 'Peptostreptococcaceae' for which a complete genome sequence is described. The 1,998,633 bp long genome (chromosome and one plasmid) with its 1852 protein-coding and 61 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Beutenbergia cavernae (Groth et al. 1999) is the type species of the genus and is of phylogenetic interest because of its isolated location in the actinobacterial suborder Micrococcineae. B. cavernae HKI 0122(T) is a Gram-positive, non-motile, non-spore-forming bacterium isolated from a cave in Guangxi (China). B. cavernae grows best under aerobic conditions and shows a rod-coccus growth cycle. Its cell wall peptidoglycan contains the diagnostic L-lysine <-- L-glutamate interpeptide bridge. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first completed genome sequence from the poorly populated micrococcineal family Beutenbergiaceae, and this 4,669,183 bp long single replicon genome with its 4225 protein-coding and 53 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Capnocytophaga ochracea (Prevot et al. 1956) Leadbetter et al. 1982 is the type species of the genus Capnocytophaga. It is of interest because of its location in the Flavobacteriaceae, a genomically not yet charted family within the order Flavobacteriales. The species grows as fusiform to rod shaped cells which tend to form clumps and are able to move by gliding. C. ochracea is known as a capnophilic (CO(2)-requiring) organism with the ability to grow under anaerobic as well as aerobic conditions (oxygen concentration larger than 15%), here only in the presence of 5% CO(2). Strain VPI 2845(T), the type strain of the species, is portrayed in this report as a gliding, Gram-negative bacterium, originally isolated from a human oral cavity. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first completed genome sequence from the flavobacterial genus Capnocytophaga, and the 2,612,925 bp long single replicon genome with its 2193 protein-coding and 59 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Rhodothermus marinus Alfredsson et al. 1995 is the type species of the genus and is of phylogenetic interest because the Rhodothermaceae represent the deepest lineage in the phylum Bacteroidetes. R. marinus R-10(T) is a Gram-negative, non-motile, non-spore-forming bacterium isolated from marine hot springs off the coast of Iceland. Strain R-10(T) is strictly aerobic and requires slightly halophilic conditions for growth. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of the genus Rhodothermus, and only the second sequence from members of the family Rhodothermaceae. The 3,386,737 bp genome (including a 125 kb plasmid) with its 2914 protein-coding and 48 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Jonesia denitrificans (Prevot 1961) Rocourt et al. 1987 is the type species of the genus Jonesia, and is of phylogenetic interest because of its isolated location in the actinobacterial suborder Micrococcineae. J. denitrificans is characterized by a typical coryneform morphology and is able to form irregular nonsporulating rods showing branched and club-like forms. Coccoid cells occur in older cultures. J. denitrificans is classified as a pathogenic organism for animals (vertebrates). The type strain whose genome is described here was originally isolated from cooked ox blood. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a member of the genus for which a complete genome sequence is described. The 2,749,646 bp long genome with its 2558 protein-coding and 71 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Eggerthella lenta (Eggerth 1935) Wade et al. 1999, emended Wurdemann et al. 2009 is the type species of the genus Eggerthella, which belongs to the actinobacterial family Coriobacteriaceae. E. lenta is a Gram-positive, non-motile, non-sporulating pathogenic bacterium that can cause severe bacteremia. The strain described in this study has been isolated from a rectal tumor in 1935. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of the genus Eggerthella, and the 3,632,260 bp long single replicon genome with its 3123 protein-coding and 58 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
BACKGROUND: Pseudomonas fluorescens are common soil bacteria that can improve plant health through nutrient cycling, pathogen antagonism and induction of plant defenses. The genome sequences of strains SBW25 and Pf0-1 were determined and compared to each other and with P. fluorescens Pf-5. A functional genomic in vivo expression technology (IVET) screen provided insight into genes used by P. fluorescens in its natural environment and an improved understanding of the ecological significance of diversity within this species. RESULTS: Comparisons of three P. fluorescens genomes (SBW25, Pf0-1, Pf-5) revealed considerable divergence: 61% of genes are shared, the majority located near the replication origin. Phylogenetic and average amino acid identity analyses showed a low overall relationship. A functional screen of SBW25 defined 125 plant-induced genes including a range of functions specific to the plant environment. Orthologues of 83 of these exist in Pf0-1 and Pf-5, with 73 shared by both strains. The P. fluorescens genomes carry numerous complex repetitive DNA sequences, some resembling Miniature Inverted-repeat Transposable Elements (MITEs). In SBW25, repeat density and distribution revealed 'repeat deserts' lacking repeats, covering approximately 40% of the genome. CONCLUSIONS: P. fluorescens genomes are highly diverse. Strain-specific regions around the replication terminus suggest genome compartmentalization. The genomic heterogeneity among the three strains is reminiscent of a species complex rather than a single species. That 42% of plant-inducible genes were not shared by all strains reinforces this conclusion and shows that ecological success requires specialized and core functions. The diversity also indicates the significant size of genetic information within the Pseudomonas pan genome.
Desulfotomaculum acetoxidans Widdel and Pfennig 1977 was one of the first sulfate-reducing bacteria known to grow with acetate as sole energy and carbon source. It is able to oxidize substrates completely to carbon dioxide with sulfate as the electron acceptor, which is reduced to hydrogen sulfide. All available data about this species are based on strain 5575(T), isolated from piggery waste in Germany. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a Desulfotomaculum species with validly published name. The 4,545,624 bp long single replicon genome with its 4370 protein-coding and 100 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
Halomicrobium mukohataei (Ihara et al. 1997) Oren et al. 2002 is the type species of the genus Halomicrobium. It is of phylogenetic interest because of its isolated location within the large euryarchaeal family Halobacteriaceae. H. mukohataei is an extreme halophile that grows essentially aerobically, but can also grow anaerobically under a change of morphology and with nitrate as electron acceptor. The strain, whose genome is described in this report, is a free-living, motile, Gram-negative euryarchaeon, originally isolated from Salinas Grandes in Jujuy, Andes highlands, Argentina. Its genome contains three genes for the 16S rRNA that differ from each other by up to 9%. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence from the poorly populated genus Halomicrobium, and the 3,332,349 bp long genome (chromosome and one plasmid) with its 3416 protein-coding and 56 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (E. Schnepf, N. Crickmore, J. Van Rie, D. Lereclus, J. Baum, J. Feitelson, D. R. Zeigler, and D. H. Dean, Microbiol. Mol. Biol. Rev. 62:775-806, 1998). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (L. Radnedge, P. Agron, K. Hill, P. Jackson, L. Ticknor, P. Keim, and G. Andersen, Appl. Environ. Microbiol. 69:2755-2764, 2003).
Leguminous plants (such as peas and soybeans) and rhizobial soil bacteria are symbiotic partners that communicate through molecular signaling pathways, resulting in the formation of nodules on legume roots and occasionally stems that house nitrogen-fixing bacteria. Nodule formation has been assumed to be exclusively initiated by the binding of bacterial, host-specific lipochito-oligosaccharidic Nod factors, encoded by the nodABC genes, to kinase-like receptors of the plant. Here we show by complete genome sequencing of two symbiotic, photosynthetic, Bradyrhizobium strains, BTAi1 and ORS278, that canonical nodABC genes and typical lipochito-oligosaccharidic Nod factors are not required for symbiosis in some legumes. Mutational analyses indicated that these unique rhizobia use an alternative pathway to initiate symbioses, where a purine derivative may play a key role in triggering nodule formation.
Chemoautotrophic endosymbionts are the metabolic cornerstone of hydrothermal vent communities, providing invertebrate hosts with nearly all of their nutrition. The Calyptogena magnifica (Bivalvia: Vesicomyidae) symbiont, Candidatus Ruthia magnifica, is the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced, revealing a suite of metabolic capabilities. The genome encodes major chemoautotrophic pathways as well as pathways for biosynthesis of vitamins, cofactors, and all 20 amino acids required by the clam.
Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the B. cereus sensu lato group. While independently derived strains of B. anthracis reveal conspicuous sequence homogeneity, environmental isolates of B. cereus and B. thuringiensis exhibit extensive genetic diversity. Here we report the sequencing and comparative analysis of the genomes of two members of the B. cereus group, B. thuringiensis 97-27 subsp. konkukian serotype H34, isolated from a necrotic human wound, and B. cereus E33L, which was isolated from a swab of a zebra carcass in Namibia. These two strains, when analyzed by amplified fragment length polymorphism within a collection of over 300 of B. cereus, B. thuringiensis, and B. anthracis isolates, appear closely related to B. anthracis. The B. cereus E33L isolate appears to be the nearest relative to B. anthracis identified thus far. Whole-genome sequencing of B. thuringiensis 97-27and B. cereus E33L was undertaken to identify shared and unique genes among these isolates in comparison to the genomes of pathogenic strains B. anthracis Ames and B. cereus G9241 and nonpathogenic strains B. cereus ATCC 10987 and B. cereus ATCC 14579. Comparison of these genomes revealed differences in terms of virulence, metabolic competence, structural components, and regulatory mechanisms.
We report here a comparative analysis of the genome sequence of Methanosarcina barkeri with those of Methanosarcina acetivorans and Methanosarcina mazei. The genome of M. barkeri is distinguished by having an organization that is well conserved with respect to the other Methanosarcina spp. in the region proximal to the origin of replication, with interspecies gene similarities as high as 95%. However, it is disordered and marked by increased transposase frequency and decreased gene synteny and gene density in the distal semigenome. Of the 3,680 open reading frames (ORFs) in M. barkeri, 746 had homologs with better than 80% identity to both M. acetivorans and M. mazei, while 128 nonhypothetical ORFs were unique (nonorthologous) among these species, including a complete formate dehydrogenase operon, genes required for N-acetylmuramic acid synthesis, a 14-gene gas vesicle cluster, and a bacterial-like P450-specific ferredoxin reductase cluster not previously observed or characterized for this genus. A cryptic 36-kbp plasmid sequence that contains an orc1 gene flanked by a presumptive origin of replication consisting of 38 tandem repeats of a 143-nucleotide motif was detected in M. barkeri. Three-way comparison of these genomes reveals differing mechanisms for the accrual of changes. Elongation of the relatively large M. acetivorans genome is the result of uniformly distributed multiple gene scale insertions and duplications, while the M. barkeri genome is characterized by localized inversions associated with the loss of gene content. In contrast, the short M. mazei genome most closely approximates the putative ancestral organizational state of these species.
