Plants of Convolvulus arvensis exhibiting symptoms of undersized leaves, shoot proliferation and yellowing, collectively defined as bindweed yellows, were sampled in different regions of Europe and assessed for phytoplasma infection by PCR amplification using phytoplasma universal rRNA operon primer pairs. Positive results were obtained for all diseased plants. RFLP analysis of amplicons comprising the16S rRNA gene alone or the16S rRNA gene and 16-23S intergenic spacer region indicated that the detected phytoplasmas were distinguishable from all other previously described rRNA gene sequences. Analysis of 16S rRNA gene sequences derived from seven selected phytoplasma strains (BY-S57/11, BY-S62/11, BY-I1015, BY-I1016, BY-BH1, BY-BH2 and BY-G) showed that they were nearly identical (99.9–100 % gene sequence similarity) but shared less than 97.5 % similarity with comparable sequences of other phytoplasmas. Thus, BY phytoplasmas represent a new taxon whose closest relatives are stolbur phytoplasma strains and ‘ Candidatus Phytoplasma fragariae ’ with which they share 97.2 % and 97.1 % 16S rRNA gene sequence similarity, respectively. Phylogenetic analysis of 16S rRNA gene sequences confirmed that bindweed yellows phytoplasma strains collectively represent a distinct lineage within the phytoplasma clade and share a common ancestor with previously published or proposed ‘Candidatus Phytoplasma’ taxa within a major branch including aster yellows and stolbur phytoplasmas. On the basis of unique 16S rRNA gene sequences and biological properties that include a single host plant species and a geographical distribution limited to parts of Europe, the bindweed yellows (BY) phytoplasmas represent a coherent but discrete taxon, ‘Candidatus Phytoplasma convolvuli’, with strain BY-S57/11 (GenBank accession no. JN833705) as the reference strain.
Four Gram-stain-positive, catalase-negative, coccus-shaped bacterial strains were isolated from multiple blood cultures of patients with endocarditis, meningitis and spondylodiscitis. The isolates were tentatively identified as viridans streptococci on the basis of phenotypic characteristics. Comparative 16S rRNA gene sequencing studies showed that the organisms were members of the Streptococcus mitis group but did not correspond to any recognized species. The nearest phylogenetic relative was S. mitis ATCC 49456T, with 98.6 % sequence similarity. The representative strain AZ_3aT showed less than 96.8, 97.6, 94.5 and 95.5 % similarity to the phylogenetically most closely related species by recA, rpoB, sodA and groEL gene sequence analysis, respectively. DNA–DNA hybridization analyses showed a low reassociation value of 32.2 % between strain AZ_3aT and S. mitis DSM 12643T. Reassociation values with members of other S. mitis group species ranged from 27.3 to 49.7 %. The G+C content of the DNA was 40.0 mol%. Based on our biochemical and molecular analyses, the isolates represent a novel species, for which the name Streptococcus tigurinus sp. nov. is proposed. The type strain is AZ_3aT ( = CCOS 600T = DSM 24864T).
A novel mesophilic, strictly anaerobic bacterium, strain BMT, was isolated from food industry wastewater. The cells were motile, non-spore-forming rods and stained Gram-negative. Growth of strain BMT was observed at 16–44 °C (optimum 37 °C) and pH 6.0–9.0 (optimum pH 7.5). The NaCl concentration range for growth was 0–8 % (optimum 1.5 %, w/v). Strain BMT was chemo-organotrophic, using a few sugars and amino acids as sole carbon and energy sources. The fermentation products from peptone-yeast extract broth were propionate, formate, acetate, ethanol and isovalerate. Indole, NH3 and H2S were produced from peptone. No respiratory quinones could be detected. The major fatty acids were iso-C15 : 0 (39.3 %), iso-C15 : 0 dimethyl acetal (10.1 %), anteiso-C15 : 0 (7.6 %), C14 : 0 (6.1 %) and C16 : 0 (5.6 %). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol and a number of unidentified aminoglycolipids, glycolipids and phospholipids. The DNA G+C content was 28.2 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain BMT was related to various genera of the family Clostridiaceae , and its closest relatives were Sporosalibacterium faouarense SOL3f37T (94.3 % 16S rRNA gene sequence similarity), Proteiniborus ethanoligenes GWT (92.1 %) and Clostridiisalibacter paucivorans 37HS60T (92.0 %). In recognition of its distinct phenotypic and genotypic characteristics, isolate BMT is proposed to represent a novel species of a new genus, Brassicibacter mesophilus gen. nov., sp. nov. The type strain of Brassicibacter mesophilus is BMT ( = JCM 16868T = DSM 24659T).