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A Microbial Biorealm page on the genus BaumanL

Classification

Higher order taxa

Bacteria; Proteobacteria; Alphaproteobacteria; Rhodobacterales; Rhodobacteraceae

Species

NCBI: Taxonomy

Loktanella Koreensis

Description and significance

Members of the genus Loktanella have been isolated from microbial mats and marine environments¹, which is why the genus was named after Tjhing-Lok Tan from the Alfred Wegener Institute in Bremerhaven because of his contribution to the understanding of marine and polar bacteriology and ecology. Bacteria in this genus are Gram-negative bacilli (rod-shaped cells) that metabolize by strictly aerobic means and are chemoheterotrophic (gain energy from organic chemical compounds). Loktanella are moderately halotolerant (adapted to conditions of high salinity), do not produce spores, are not observed to be motile, and grow at an optimum temperature of 25^oC.²

Loktanella koreensis is a novel species, discovered in 2006 in the Homi cape of Pohang City, Republic of Korea. The bacteria is a Gram-negative, non-motile, non-spore-forming, rod- to ovid-shape. The cells arrange themselves in round, convex, light beige colonies with clear margins. L. koreensis is able to grow between 5-30^oC, at a pH between 6-9, and with up to 5% NaCl.³

Genome structure

L. koreensis has the highest sequence similarity with Loktanella rosea; 93.5–96.1 %. It is defined by a G+C content of 60.0 mol% in the genomic DNA and a predominant ubiquinone of Q-10. Major fatty acids present are 18 : 1ω7c, 18 : 0 and 18 : 1ω7c 11-methyl.³

Other information about the genome has not been identified at present.

Cell structure and metabolism

The bacteria within the genus Loktanella are strictly aerobic, chemoheterotrophs.² The species Loktanella koreensis shares these properties, but also differ in many aspects. L. koreensis grows on marine agar but not on nutrient agar, trypic soy agar, or MacConkey agar. It does not metabolize carbohydrates, pectin, or starch and acids are not produced from any substrates. Along with these traits, L. koreensis tests positive for catalase, oxidase, nitrate reduction, and hydrogen sulfide production. However, the bacteria tests negative for arginine dihdrolase, glucose fermentation, indole produciton, urease, and Voges-Proskauer reaction.³

Ecology

Bacterial within the genus Loktanella have been isolated from microbial mats in Antarctic lakes and marine environments such as marine biofilms, sediment, sea sand, and sea water.¹ The presence of bacteria in aquatic environments has been correlated to the presence of algal blooms. This correlation may suggest that Loktanella play an important role in sulfur cycling.² Loktanella koreensis was discovered during a study of the bacterial diversity in sea sands. It was isolated in the Homi cape of Pohang City, Republic of Korea.³

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Current Research and or Application to Biotechnology

Loktanella is a relatively new genus (discovered in 2004 by Van Trappen²) with new species being discovered yearly. However, no present research is being conducted on L. koreensis.

• Loktanella maricola sp. nov., isolated from seawater of the East Sea in Korea; IJSEM August 2007
• Loktanella atrilutea sp. nov., isolated from seawater in Japan; IJSEM September 2007
• Loktanella pyoseonensis sp. nov., isolated from beach sand, and emended description of the genus Loktanella; IJSEM April 2010
• Loktanella litorea sp. nov., isolated from seawater; IJSEM March 2012
• Loktanella tamlensis sp. nov., isolated from seawater; IJSEM March 2012

It has also been suggested that the presence of bacteria in aquatic environments may be correlated to the presence of algal blooms. This may suggest that Loktanella play an important role in sulfur cycling.²

References

1. Moon, YG., Seo, SH., Lee, SD., and Heo, MS. "Loktanella pyseonesis sp. nov., isolated from beach sand, and emended description of the genus Loktanella". International Journal of Systematic and Evolutionary Microbiology. 2010. Volume 60. p. 785-789.
2. Van Trappen, S., Mergaert, J., and Swings, J. "Loktanella salsilacus gen. nov., sp. nov., Loktanella fryxellensis sp. nov. and Loktanella vestfoldensis sp. nov., new members of the Rhodobacter group, isolated from microbial mats in Antarctic lakes". International Journal of Systematic and Evolutionary Mirobiology. 2004. Volume 54. p. 1263-1269.
3. Weon, HY., Kim, BY., Yoo, SH., Kim, JS., Kwon, SW., Go, SJ., and Stackebrandt, E. "Loktanella Koreensis sp. nov., isolated from sea sand in Korea". International Journal of Systematic and Evolutionary Microbiology. 2006. Volume 56. p. 2199-2202.

Edited by student of Dr. Lynn M Bedard, DePauw University http://www.depauw.edu