Pseudomonas carbonaria sp. nov., isolated from charcoal

A beige-pigmented, oxidase-positive bacterial isolate, Wesi-4^T, isolated from charcoal in 2012, was examined in detail by applying a polyphasic taxonomic approach. Cells of the isolates were rod shaped and Gram-stain negative. Examination of the 16S rRNA gene sequence of the isolate revealed highest sequence similarities to the type strains of Pseudomonas matsuisoli and Pseudomonas nosocomialis (both 97.3 %). Phylogenetic analyses on the basis of the 16S rRNA gene sequences indicated a separate position of Wesi-4^T, which was confirmed by multilocus sequence analyses (MLSA) based on the three loci gyrB, rpoB and rpoD and a core genome-based phylogenetic tree. Genome sequence based comparison of Wesi-4^T and the type strains of P. matsuisoli and P. nosocomialis yielded average nucleotide identity values <95 % and in silico DNA-DNA hybridization values <70 %, respectively. The polyamine pattern contains the major amines putrescine, cadaverine and spermidine. The quinone system contains predominantly ubiquinone Q-9 and in the polar lipid profile diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine are the major lipids. The fatty acid contains predominantly C_16 : 0, summed feature 3 (C_16 : 1ω7c and/or C_16 : 1ω6c) and summed feature 8 (C_18 : 1ω7c and/or C_18 : 1 ω6c). In addition, physiological and biochemical tests revealed a clear phenotypic difference from P. matsuisoli. These cumulative data indicate that the isolate represents a novel species of the genus Pseudomonas for which the name Pseudomonas carbonaria sp. nov. is proposed with Wesi-4^T (=DSM 110367^T=CIP 111764^T=CCM 9017^T) as the type strain.

Pseudomonas phragmitis sp. nov., isolated from petroleum polluted river sediment

A Gram-stain-negative, rod-shaped bacterium, motile by means of a single polar flagellum, designated S-6-2^T, was isolated from petroleum polluted river sediment in Huangdao, Shandong Province, PR China. The 16S rRNA gene sequence analysis revealed that S-6-2^T represented a member of the genus Pseudomonas, sharing the highest sequence similarities with Pseudomonas parafulva (97.5 %) and Pseudomonas fulva (97.5 %). Phylogenetic analysis based on 16S rRNA gene, concatenated 16S rRNA, gyrB, rpoB and rpoD genes and genome core-genes indicated that S-6-2^T was affiliated with the members of the Pseudomonas pertucinogena group. The average nucleotide identity (ANI) and genome-to-genome distance between the whole genome sequences of S-6-2^T and closely related species of the genus Pseudomonas within the P. pertucinogena group were less than 77.94 % and 20.5 %, respectively. Differences in phenotypic characteristics were also found between S-6-2^T and the closely related species. The major cellular fatty acids (>10 %) were summed feature 8 (C_18 : 1ω7c/ C_{18  : 1}ω6c), C_16 : 0, C_17 : 0cyclo and C_12 : 0. The predominant respiratory quinone was ubiquinone 9. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), one unidentified lipid (L1), two unidentified phospholipids (PL1 and PL2) and an aminophospholipid (APL). The DNA G+C content of the genome of S-6-2^T was 60.1 mol%. On the basis of the evidence from the polyphasic taxonomic study, strain S-6-2^T can be classified as representative of a novel species of the genus Pseudomonas, for which the name Pseudomonas phragmitis sp. nov. is proposed. The type strain is S-6-2^T (=CGMCC 1.15798^T=KCTC 52539^T).

The current status on the taxonomy of Pseudomonas revisited: An update

The genus Pseudomonas described in 1894 is one of the most diverse and ubiquitous bacterial genera which encompass species isolated worldwide. In the last years more than 70 new species have been described, which were isolated from different environments, including soil, water, sediments, air, animals, plants, fungi, algae, compost, human and animal related sources. Some of these species have been isolated in extreme environments, such as Antarctica or Atacama desert, and from contaminated water or soil. Also, some species recently described are plant or animal pathogens. In this review, we revised the current status of the taxonomy of genus Pseudomonas and the methodologies currently used for the description of novel species which includes, in addition to the classic ones, new methodologies such as MALDI-TOF MS, MLSA and genome analyses. The novel Pseudomonas species described in the last years are listed, together with the available genome sequences of the type strains of Pseudomonas species present in different databases.

Purification and properties of a novel quizalofop-p-ethyl-hydrolyzing esterase involved in quizalofop-p-ethyl degradation by Pseudomonas sp. J-2

Quizalofop-p-ethyl (QPE) is a post-emergence herbicide that effectively controls grass weeds and is often detected in the environment. However, the biochemical and molecular mechanisms of QPE degradation in the environment remains unclear. In this study, a highly effective QPE-degrading bacterial strain J-2 was isolated from acclimated activated sludge and identified as a Pseudomonas sp., containing the QPE breakdown metabolite quizalofop acid (QA) identified by Liquid Chromatography-Ion Trap-Mass Spectrometry (LC-IT-MSⁿ) analysis. A novel QPE hydrolase esterase-encoding gene qpeH was cloned from strain J-2 and functionally expressed in Escherichia coli BL21 (DE3). The specific activity of recombinant QpeH was 198.9 ± 2.7 U mg⁻¹ for QPE with K_m and K_cat values of 41.3 ± 3.6 μM and 127.3 ± 4.5 s⁻¹. The optimal pH and temperature for the recombinant QpeH were 8.0 and 30 °C, respectively and the enzyme was activated by Ca²⁺, Cd²⁺, Li⁺, Fe³⁺ and Co²⁺ and inhibited by Ni²⁺, Fe²⁺, Ag⁺, DEPC, SDS, Tween 80, Triton X, β-mercaptoethanol, PMSF, and pCMB. In addition, the catalytic efficiency of QpeH toward different AOPP herbicides in descending order was as follows: fenoxaprop-P-ethyl > quizalofop-P-tefuryl > QPE > haloxyfop-P-methyl > cyhalofopbutyl > clodinafop-propargyl. On the basis of the phylogenetic analysis and multiple sequence alignment, the identified enzyme QpeH, was clustered with esterase family V, suggesting a new member of this family because of its low similarity of amino acid sequence with esterases reported previously.