Photobacterium kishitanii sp nov., a luminous marine bacterium symbiotic with deep-sea fishes
Ast, J.C.; Cleenwerck, I.; Engelbeen, K.; Urbanczyk, H.; Thompson, F.L.; De Vos, P. (2007). Photobacterium kishitanii sp nov., a luminous marine bacterium symbiotic with deep-sea fishes. Int. J. Syst. Evol. Microbiol. 57: 2073-2078. dx.doi.org/10.1099/ijs.0.65153-0 In: International Journal of Systematic and Evolutionary Microbiology. Society for General Microbiology: Reading. ISSN 1466-5026; e-ISSN 1466-5034, more |  |
| Authors | | Top | - Ast, J.C.
- Cleenwerck, I., more
- Engelbeen, K.
| - Urbanczyk, H.
- Thompson, F.L., more
- De Vos, P., more
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| Abstract | Six representatives of a luminous bacterium commonly found in association with deep, cold-dwelling marine fishes were isolated from the light organs and skin of different fish species. These bacteria were Gram-negative, catalase-positive, and weakly oxidase-positive or oxidase-negative. Morphologically, cells of these strains were coccoid or coccoid-rods, occurring singly or in pairs, and motile by means of polar flagellation. After growth on seawater-based agar medium at 22 °C for 18 h, colonies were small, round and white, with an intense cerulean blue luminescence. Analysis of 16S rRNA gene sequence similarity placed these bacteria in the genus Photobacterium. Phylogenetic analysis based on seven housekeeping gene sequences (16S rRNA gene, gapA, gyrB, pyrH, recA, rpoA and rpoD), seven gene sequences of the lux operon (luxC, luxD, luxA, luxB, luxF, luxE and luxG) and four gene sequences of the rib operon (ribE, ribB, ribH and ribA), resolved the six strains as members of the genus Photobacterium and as a clade distinct from other species of Photobacterium. These strains were most closely related to Photobacterium phosphoreum and Photobacterium iliopiscarium. DNA–DNA hybridization values between the designated type strain, Photobacterium kishitaniipjapo.1.1T, and P. phosphoreum LMG 4233T, P. iliopiscarium LMG 19543T and Photobacterium indicum LMG 22857T were 51, 43 and 19 %, respectively. In AFLP analysis, the six strains clustered together, forming a group distinct from other analysed species. The fatty acid C17 : 0 cyclo was present in these bacteria, but not in P. phosphoreum, P. iliopiscarium or P. indicum. A combination of biochemical tests (arginine dihydrolase and lysine decarboxylase) differentiates these strains from P. phosphoreum and P. indicum. The DNA G+C content of P. kishitanii pjapo.1.1T is 40.2 %, and the genome size is approximately 4.2 Mbp, in the form of two circular chromosomes. These strains represent a novel species, for which the name Photobacterium kishitanii sp. nov. is proposed. The type strain, pjapo.1.1T (=ATCC BAA-1194T=LMG 23890T), is a luminous symbiont isolated from the light organ of the deep-water fish Physiculus japonicus. |
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