Molecular detection of Oceanobacillus iheyensis in sand of Brazilian beaches.

Oceanobacillus iheyensis strain HTE831 was isolated from deep sea mud (1,050 m) from the Iheya Ridge near Okinawa, Japan, in 1998 (Lu et al., 2001). This organism is an alkaliphilic and extremely halotolerant Bacillus-related species. Its genome has been completely sequenced and the presence of genes required for adaptation to these extreme environments was demonstrated (Takami et al., 2002). Many proteins potentially associated with roles in the regulation of intracellular osmotic pressure and pH homeostasis were shown to be coded in its 3.6 Mb genome (Takami et al., 2002). Later on, Takaki et al. (2004) identified six kinds of new insertion sequences, a group II intron, and an incomplete transposon in the genome of strain HTE831. However, surprisingly, no other strains belonging to this species were described in the literature until 2006, when Barbosa et al. studied the Gram-positive spore-forming community found associated with plants in tropical soils. Halotolerant and facultatively alkaliphilic spore-forming Gram-positive bacteria were isolated from the rhizosphere and non-rhizosphere soils of Blutaparon portulacoides (St. Hill.) Mears (Amaranthaceae). This plant first colonized embryo dunes and backshores of Southwestern Atlantic Ocean beaches (Farias and Flores, 1989). Different isolates were characterized phenotypically and analyzed by 16S rRNA gene sequencing and members of the species O. iheyensis were recovered (Barbosa et al., 2006a). Macroscopically, colonies of strains L4, L18, S1, S4, S14 and S18 are circular, creamy white, and slightly transparent. They are all strictly aerobic, catalase positive, nitrate negative, Voges-Proskauer (VP) negative, casein positive and starch hydrolysis negative. These six strains are able to grow in LB medium containing 0.5 to 20% NaCl and on pH varying from 5.7 to 9.5. They all formed a monophyletic branch with O. iheyensis strain HTE831 based on their 16S rRNA gene sequences (DQ058363‒ DQ058368; Barbosa et al., 2006a). Therefore, on the basis of the results of this investigation, different O. iheyensis strains isolated from B. portulacoides became available for further studies. Hence, it is now reasonable to consider that strains of O. iheyensis are not restricted to extreme environments and may be spread in different habitats in the world. The study of O. iheyensis strains may lead us to a better understanding of life in saline and/or alkaline environments. New strains of O. iheyensis may also offer a potential source for the discovery of bioactive compounds with industrial value, such as antibiotics, biosurfactants and exopolysaccharides (Margesin and Schinner, 2001). However, no selective medium is J. Gen. Appl. Microbiol., 54, 305‒310 (2008)