Submitted to: National Center for Biotechnology Information (NCBI)
Publication Type: Other
Publication Acceptance Date: 11/22/2005
Publication Date: 12/15/2005
Citation: Hunter, W.J., Kuykendall, L.D. 2005. Aeromonas salmonicida achromogenes (a selenite-reducing bacterium)16s (small r)rna gene complete sequence. National Center for Biotechnology Information (NCBI), GenBank sequence submission Accession # AY910844. Interpretive Summary: This study used 16S rRNA gene sequence methods to identify a selenite reducing bacterium, Aeromonas salmonicida. In the Western United States selenate or selenite are groundwater problems on almost 160,000 sq. miles of land. Agricultural activities on these lands can result in mobilization of soluble selenium compounds, selenate and selenite, and in ground and surface water contamination. In addition, refinery wastewaters, a consequence of the refining of crude oil, contain large amounts of selenite and are a significant environmental source of selenium. Selenite is one of the most toxic elements in the environment and ingestion of excess amounts can cause damage to the nervous system. Remediation procedures are needed to remove excess selenium compounds from water. Biological methods that use microorganisms to remove the selenite from water may be the most practical approach. It is important that bacteria that are capable of removing large amounts of selenite be isolated, characterized, and identified.
Technical Abstract: This study used 1540 base pair 16S rRNA gene sequence methods to confirm the identify of a bacterium that reduces selenite to elemental red selenium (Se0) as Aeromonas salmonicida achromogenes (syn Haemophilus piscium). Previous biochemical testing had indicated that the bacterium was likely to be an Aeromonas sp. Thus the two identification approachs are in good agreement. The isolate was obtained from a laboratory scale permeable reactive barrier that contained vegetable oil as an electron donor and that was supplied with water contaminated with selenite. The 16S rRNA gene sequence suggests that strain C278 is very closely related to Haemophilus piscium, Aeromonas bestiarum, and A. salmonicida with the closest 16S rRNA match occurring between strain C278 and H. piscium where there was no difference in the gene sequence. However, H. piscium is generally considered to be an atypical achromogenic A. salmonicida. Generally, the Percent Genetic Difference between bacteria of the same species will range from about 0.5 to 3.0% and will usually average about 1%. Strain C278 showed only a 0.03% 16S rRNA genetic difference from A. salmonicida. Thus, we consider C278 to be an atypical achromogenic A. salmonicida.