Chryseobacterium schmidteae sp. nov. a novel bacterial species isolated from planarian Schmidtea mediterranea

Chryseobacterium pyrolae sp. nov., isolated from the rhizosphere soil of Pyrola calliantha H

A novel Gram-stain-negative, aerobic, non-motile, rod-shaped bacterium, designated pc2-12T, was isolated from the rhizosphere soil of the herb Pyrola calliantha collected from arid areas of Tibet. The strain grew most vigorously with 1 % (w/v) NaCl, at pH 7.0 and at 25 °C. According to the results of 16S rRNA gene sequence analysis, pc2-12T was closely related to the members of the genus Chryseobacterium, with highest levels of sequence similarity to Chryseobacterium viscerum 687B-08T (98.42 %), Chryseobacterium oncorhynchi 701B-08T (98.11 %) and Chryseobacterium ureilyticum DSM 18017T (97.98 %). The average nucleotide identity values between pc2-12T and C. viscerum 687B-08T, C. oncorhynchi 701B-08T and C. ureilyticum DSM 18017T were 79.71, 79.49 and 79.26 %, respectively. The in silico DNA-DNA hybridisation values between pc2-12T and C. viscerum 687B-08T, C. oncorhynchi 701B-08T and C. ureilyticum DSM 18017T were 23.30, 23.00 and 22.90 %, respectively. The draft genome sequence of pc2-12T was 4.64 Mb long, with DNA G+C content of 37.0 mol%. The fatty acids contained in the cells of pc2-12T were mainly composed of iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The main polar lipid was phosphatidylethanolamine. MK-6 was the sole respiratory quinone. On the basis of the results of analysis of all the data described, pc2-12T is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium pyrolae sp. nov., is proposed. The type strain is pc2-12T (=GDMCC 1.3256T= JCM 35712T).

Chryseobacterium paludis sp. nov. and Chryseobacterium foetidum sp. nov. Isolated from the Aquatic Environment, South Korea

Two novel bacterial species CJ51^T and CJ63^T belonging to the genus Chryseobacterium were isolated from the Upo wetland and the Han River, South Korea, respectively. Cells of these strains were Gram-stain-negative, aerobic, non-motile, rod-shaped, and catalase- and oxidase-positive. Both strains were shown to grow optimally at 30 °C and pH 7 in the absence of NaCl on tryptic soy agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains CJ51^T and CJ63^T belonged to the genus Chryseobacterium and were most closely related to Chryseobacterium piperi CTM^T and Chryseobacterium piscicola VQ-6316s^T with 98.47% and 98.46% 16S rRNA sequence similarities, respectively. The average nucleotide identity values of strains CJ51^T and CJ63^T with its closely related type strains Chryseobacterium piperi CTM^T and Chryseobacterium piscicola VQ-6316s^T were 81.9% and 82.1%, respectively. The major fatty acids of strains CJ51^T and CJ63^T were iso-C_15:0, iso-C_17:0 3-OH and summed feature 9 (C_16:0 10-methyl and/or iso-C_17:1ω9c). Menaquinone 6 (MK-6) was identified as the primary respiratory quinone in both strains. The major polar lipids of strains CJ51^T and CJ63^T were phosphatidylethanolamine and several unidentified amino lipids and lipids. Based on polyphasic taxonomy data, strains CJ51^T and CJ63^T represent novel species of the genus Chryseobacterium, for which names Chryseobacterium paludis sp. nov. and Chryseobacterium foetidum sp. nov. are proposed respectively. The type strains are CJ51^T (= KACC 22749^T = JCM 35632^T) and CJ63^T (= KACC 22750^T = JCM 35633^T).

Culturomics revealed the bacterial constituents of the microbiota of a 10-year-old laboratory culture of planarian species S. mediterranea

The planarian species Schmidtea mediterranea is a flatworm living in freshwater that is used in the research laboratory as a model to study developmental and regeneration mechanisms, as well as antibacterial mechanisms. However, the cultivable microbial repertoire of the microbes comprising its microbiota remains unknown. Here, we characterized the bacterial constituents of a 10-year-old laboratory culture of planarian species S. mediterranea via culturomics analysis. We isolated 40 cultivable bacterial species, including 1 unidentifiable species. The predominant phylum is Proteobacteria, and the most common genus is Pseudomonas. We discovered that parts of the bacterial flora of the planarian S. mediterranea can be classified as fish pathogens and opportunistic human pathogens.