In order to determine the genome variability within Pseudomonas stutzeri, 20 strains representing the seven described genomovars and strain JM300 were analyzed by using various resolution levels of rare cutting enzymes. XbaI and SpeI fingerprints revealed a high degree of heterogeneity of restriction patterns that did not correlate with the division into genomovars. However, a fragment pattern comparison led to the establishment of several groups of clonal variants within genomovars. One circular chromosome ranging in size from 3.75 to 4.64 Mb constitutes the genome of P. stutzeri strains. The I-CeuI, PacI, and SwaI low-resolution map of P. stutzeri type strain CCUG 11256 shows the locations of 12 genes, including rrn operons and the origin of replication. I-CeuI digests of the 20 strains studied plus the positions of six genes allowed a comparison of the rrn backbone organization within genomovars; the four rrn operons seemed to be at similar locations with respect to the origin of replication, as did the rest of the genes. However, a comparison of I-CeuI cleavage maps of the genomovar reference strains revealed a diverse genome organization in the genomovars relative to rrn operons and gene locations. In most genomovars, rrn operons are not arranged around the origin of replication but are equally distributed on the chromosome. Strain JM300 does not belong to any described genomovar, as determined from the organization of its genome. Large chromosomal rearrangements seem to be responsible for the differences in superordinate genome structure and must have played an important role in P. stutzeri diversification and niche colonization. An ancestral chromosome is suggested, and some plausible pathways for the generation of the various genome structures are proposed.

Bacteria identified and classified as Pseudomonas stutzeri, on the basis of traditional criteria, are recognized to be markedly heterogeneous, such that a systematic phenotypic characterization has not been correlated with genotypic groupings (i.e. genomovars) based upon DNA-DNA similarities. The internally transcribed 16S-23S rDNA spacer (ITS1) regions of P. stutzeri were analysed with respect to the ability of these nucleic acid regions to differentiate and identify the genomic groups (i.e. genomovars) of P. stutzeri. The ITS1s of 34 strains of P. stutzeri were amplified by PCR and the PCR product was subjected to RFLP analysis, which allowed the differentiation and identification of the strains to their respective genomovars. Sequence determination and analysis of ITS1s supported further the results obtained by RFLP, i.e. nucleotide signatures were identified in strains belonging to different genomovars. The ITS1s of all strains of P. stutzeri contained the tandem tRNA(Ile)/tRNA(Ala) genes and did not exhibit distinct sequence heterogeneity between different operons of a strain. Phylogenetically informative variable sites were located, exclusively, in non-coding regions. The results of the RFLP and sequence analysis of ITS1s supported and correlated with the phylogenetic relationships estimated from 16S rRNA gene sequence comparisons and DNA-DNA hybridizations, offering an alternative tool for genomovar and species differentiation.

The phenotypic characteristic of strain AW-1(T) of Pseudomonas chloritidismutans that is most relevant from the taxonomic point of view appears to be the capacity of growth under anaerobic conditions using chlorate as electron acceptor. This property is not restricted to this species only within the genus Pseudomonas, since it is also present in strains of genomovars 1 or 5, and 3 of Pseudomonas stutzeri. P. chloritidismutans has been described as a non-denitrifying species, but the isolation of variants that are able to grow anaerobically in the presence of nitrate is possible after subcultivation under selective conditions. The subdivision of P. stutzeri into a number of species on the basis of these characteristics does not help to clarify the phylogenetic relationships among the members of an otherwise coherent group of strains, and the considerations presented in this communication support the reclassification of the new species name P. chloritidismutans, which in our opinion, should be considered as a Junior name of P. stutzeri. A multilocus sequence analysis, together with a phenotypic analysis of the anaerobic oxidative metabolism, gives new insights into the phylogeny and evolution of the species.

Here we report the complete genome sequence of Pseudomonas stutzeri strain CGMCC 1.1803 (equivalent to ATCC 17588), the type strain of P. stutzeri, which encodes 4,138 open reading frames on a 4,547,930-bp circular chromosome. The CGMCC 1.1803 genome contains genes involved in denitrification, benzoate/catechol degradation, chemotaxis, and other functions.

A genome and fatty acid analysis of 16 Pseudomonas stutzeri reference strains having DNA compositions ranging from 62.2 to 65.5 mol% G+C was performed by pulsed-field gel electrophoresis of XbaI and SpeI macrorestriction fragments and gas chromatography of total cellular fatty acids. Macrorestriction fragment patterns were evaluated by using previously described algorithms (D. Grothues and B. T?mmler, Mol. Microbiol. 5:2763-2776, 1991), and the results allowed us to subdivide the species into two groups which correlated with G+C content. Two examples of recent strain divergence were observed among clinical isolates, but in general a marked degree of heterogeneity was observed in the macrorestriction fragment patterns, and even phenotypically similar strains produced divergent patterns. While the differences were not sufficiently great to exclude any strain from P. stutzeri, they suggest that recombination and niche-specific selection may be significant factors responsible for generating and maintaining the heterogeneity inherent in the species. Genome sizes were estimated from the sums of SpeI restriction fragment sizes and ranged from 3.4 to 4.3 Mbp; the genome sizes of the low-G+C-content strains (G+C contents, approximately 62 mol%) were confined to a narrow range between 3.9 and 4.1 Mbp. An examination of the distributions of macrorestriction fragments resulting from digestion with XbaI and SpeI showed that both distributions differed significantly from the expected (random) distribution, suggesting that there is a supragenic level of chromosomal organization. An analysis of fatty acid methyl ester data by using Microbial Identification System software revealed a similar correlation between phenotype and G+C content, indicating that division of the species is possible by the method used in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

The Bacteriological Code deals with the nomenclature of prokaryotes. This may include existing names (the Approved Lists of Bacterial Names) as well as new names and new combinations. In this sense the Code is also dealing indirectly with taxonomic opinions. However, as with most codes of nomenclature there are no mechanisms for formally recording taxonomic opinions that do not involve the creation of new names or new combinations. In particular, it would be desirable for taxonomic opinions resulting from the creation of synonyms or emended descriptions to be made widely available to the public. In 2004, the Editorial Board of the International Journal of Systematic and Evolutionary Microbiology (IJSEM) agreed unanimously that it was desirable to cover such changes in taxonomic opinions (i.e. the creation of synonyms or the emendation of circumscriptions) previously published outside the IJSEM, and to introduce a List of Changes in Taxonomic Opinion [Notification of changes in taxonomic opinion previously published outside the IJSEM; Euz?by et al. (2004). Int J Syst Evol Microbiol 54, 1429-1430]. Scientists wishing to have changes in taxonomic opinion included in future lists should send one copy of the pertinent reprint or a photocopy or a PDF file thereof to the IJSEM Editorial Office or to the Lists Editor. It must be stressed that the date of proposed taxonomic changes is the date of the original publication not the date of publication of the list. Taxonomic opinions included in the List of Changes in Taxonomic Opinion cannot be considered as validly published nor, in any other way, approved by the International Committee on Systematics of Prokaryotes and its Judicial Commission. The names that are to be used are those that are the "correct names" (in the sense of Principle 6) in the opinion of the bacteriologist, with a given circumscription, position and rank. A particular name, circumscription, position and rank does not have to be adopted in all circumstances. Consequently, the List of Changes in Taxonomic Opinion must be considered as a service to bacteriology and it has no "official character", other than providing a centralized point for registering/indexing such changes in a way that makes them easily accessible to the scientific community.