Muricauda brasiliensis sp. nov., isolated from a mat-forming cyanobacterial culture

Abstract

Strain K001 was isolated from a cyanobacterial culture derived from Abrolhos, a reef bank microbial mat (South Atlantic Ocean-Brazil). Cells of K001 are Gram stain-negative, catalase and oxidase-positive, non-motile, rod-shaped, and with or without appendages. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain K001 belongs to the genus Muricauda. The highest strain K001 16S rRNA gene identity, ANI, and dDDH, respectively, are with M. aquimarina (98.90%, 79.23, 21.60%), M. ruestringensis (98.20%, 80.82, 23.40%), and M. lutimaris (97.86%, 79.23, 22.70%). The strain grows at 15-37 °C and between 0.5 and 10% NaCl. The major fatty acids of strain K001 are iso-C_15:0, iso-C_15:1 G, iso-C_17:0 3-OH, and summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c). The polar lipids are represented by phosphatidylethanolamine, three unidentified aminolipids, and three unidentified polar lipids. The major respiratory quinone is MK-6. The G+C content of the DNA of strain K001 is 41.62 mol%. Based on polyphasic analysis of strain K001, it was identified as a novel representative of the genus Muricauda and was named Muricauda brasiliensis sp. nov. The type strain is K001 (=CBMAI 2315^T = CBAS 752^T).

Keywords: Abrolhos reef bank; Cyanobacterial culture; Flavobacteriaceae; Muricauda brasiliensis.

Fig. 1

Maximum-likelihood (ML) phylogenetic tree based on 16S rRNA gene sequences, showing the position strain K001. Bootstrap values above 50% based on 1000 resamplings are shown at branch nodes. Bar, 0.05 substitutions per nucleotide position. Bacteroides fragilis ATCC25285 was used as an outgroup

Fig. 2

Scanning electron micrograph showing appendages found on some cells of K001 (magnification × 6000). Bar, 1 μm

Fig. 3

Chromatogram profile of (A) strain K001, showing peaks of carotenoid pigments. HPLC analysis conditions: RP-column C18 Vydac (218TP54), mobile phase 100% (v/v) MeOH, flow 1.0 ml/min. Spectrogram profile (range 400–600 nm) of main chromatogram peaks (B and C)