Oxygen tolerance of Cetobacterium somerae isolated from the gut of freshwater fish and their environments
Cetobacterium somerae is a predominant bacterium found in the gut of freshwater fish. However, being an anaerobic bacterium, its survival is believed to be prevented in oxygen-rich environments. Therefore, in this study, we investigated the oxygen tolerance of 83 C. somerae strains collected from the guts of freshwater fish, rearing water, and sediment of culture ponds and tanks. When placed in sterile bottles containing common carp- and goldfish-rearing water, C. somerae showed a 1-log decrease after 24 hours, suggesting that this organism faces challenges in growing in rearing water. Subsequently, we inoculated the bacterial strains onto agar plates and exposed them to air for 12 hours to measure the oxygen inhibition index (OII). The OII values ranged from 0.01 to 4.65 among different strains, indicating significant variation in oxygen tolerance within the bacterium. Furthermore, the OII values varied considerably depending on the isolation source, with sediment, rearing water, and gut samples showing increasing values in that order. This suggests that oxygen tolerance plays a substantial role in the ecological behavior of C. somerae.
Cahill M.M. (1990). Bacterial flora of fishes: A review. Microbial Ecology, 19: 21-41.
Finegold S.M., Vaisanen M.L., Molitoris D.R., Tomzynski T.J., Song Y., Liu C., Collins M.D., Lawson P.A. (2003). Cetobacterium somerae sp. nov. from human feces and emended description of the Genus Cetobacterium. Systematic and Applied Microbiology, 26: 177-181.
Kurosaki M., Kunimoto M., Akiyama N., Itoi S., Sugita H. (2021). Predominant gut microbiota in the early life stages of red seabream (Pagrus major) raised in indoor tanks. International Aquatic Research, 13: 219-226.
Madigan M., Bender K., Buckley D., Sattley W., Stahl D. (2017). Brock Biology of Microorganisms, 15th edition. Pearson, NJ. 1056 p.
Sakata T., Sugita H., Mitsuoka T., Kakimoto D., Kadota H. (1980). Isolation and distribution of obligate anaerobic bacteria from the intestines of freshwater Fish. Bulletin of Japanese Society of Scientific Fisheries, 46: 1249-1255.
Sakata T., Sugita H., Mitsuoka T., Kakimoto D., Kadota H. (1981): Characteristics of obligate anaerobic bacteria in the intestines of freshwater fish. Bulletin of Japanese Society of Scientific Fisheries, 47: 421-427.
Sugita H., Mizuki H. (2012). Bacterial diversity of the upper and lower intestines of the common carp (Cyprinus carpio Linnaeus, 1758) reared in an indoor tank. Journal of Applied Ichthyology, 28: 647–648.
Sugita H., Okano R., Ishigaki T., Aono E., Akiyama N., Asfie M., Deguchi Y. (1998). Changes of microflora in seawater of aquaria with recirculating water system, stocked with Japanese flounder at a juvenile stage. Aquaculture Science, 46: 237-241.
Sugita H., Tsunohara M., Ohkoshi T., Deguchi Y. (1988). The establishment of an intestinal microflora in developing goldfish (Carassius auratus) of culture ponds. Microbial Ecology, 15: 333-344.
Sugita H., Ushioka S., Kihara D., Deguchi Y. (1985) Changes in the bacterial composition of water in a carp rearing tank. Aquaculture, 44: 243-247.
Trust T.J., Bull L.M., Currie B.R., Buckley J.T. (1976). Obligate anaerobic bacteria in the gastrointestinal microflora of grass carp (Ctenopharyngodon idella), goldfish (Carassius auratus), and rainbow trout (Salmo gairdneri). Journal of the Fisheries Research Board of Canada, 36: 1174-1179.
Tsuchiya C., Sakata T., Sugita H. (2008). Novel ecological niche of Cetobacterium somerae, an anaerobic bacterium in the intestinal tracts of freshwater fish. Letters in Applied Microbiology, 46: 43-48.
Yi Y., Liang L., Wang Z., Ai P., You X., Bian C., Shi Q., Dong B. (2019). A comparative metagenomics study on gastrointestinal microbiota in amphibious mudskippers and other vertebrate animals. Animals, 9: 660.
Copyright (c) 2023 International Journal of Aquatic Biology
This work is licensed under a Creative Commons Attribution 4.0 International License.