Bacillus rigiliprofundi sp. nov., an endospore-forming, Mn-oxidizing, moderately halophilic bacterium isolated from deep subseafloor basaltic crust

Abstract

A facultatively anaerobic bacterium, designated strain 1MBB1 T , was isolated from basaltic breccia collected from 341 m below the seafloor by seafloor drilling of Rigil Guyot during Integrated Ocean Drilling Program Expedition 330. The cells were straight rods, 0.5 mm wide and 1-3 mm long, that occurred singly and in chains. Strain 1MBB1 T stained Gram-positive. Catalase and oxidase were produced. The isolate grew optimally at 30 8C and pH 7.5, and could grow with up to 12 % (w/v) NaCl. The DNA G+C content was 40.5 mol%. The major cellular fatty acids were C 16:1 v11c (26.5 %), anteiso-C 15:0 (19.5 %), C 16:0 (18.7 %) and iso-C 15:0 (10.4 %), and the cell-wall diamino acid was meso-diaminopimelic acid. Endospores of strain 1MBB1 T oxidized Mn(II) to Mn(IV), and siderophore production by vegetative cells was positive. Phylogenetic analysis of the 16S rRNA gene indicated that strain 1MBB1 T was a member of the family Bacillaceae, with Bacillus foraminis CV53 T and Bacillus novalis LMG 21837 T being the closest phylogenetic neighbours (96.5 and 96.2 % similarity, respectively). This is the first novel species described from deep subseafloor basaltic crust. On the basis of our polyphasic analysis, we conclude that strain 1MBB1 T represents a novel species of the genus Bacillus, for which we propose the name Bacillus rigiliprofundi sp. nov. The type strain is 1MBB1 T (5NCMA B78 T 5LMG 28275 T ).

Untitled

“…Evidence for active microbial life has been detected as deep as 2458 mbsf (Inagaki et al, 2015), and the introduction of molecular biology into marine ecology has led to great advances in our understanding of microbial life below the seafloor (Biddle et al, 2008;Cowen et al, 2003;Inagaki et al, 2006;Mason et al, 2010;Edgcomb et al, 2011;Orsi et al, 2013aOrsi et al, , 2013b. Much of the microbiology performed during ODP and Integrated Ocean Drilling Program expeditions has concentrated on sediment (e.g., ODP Leg 201 to the Peru margin), with the notable exception of expeditions to the Juan de Fuca Ridge (Cowen et al, 2003;Lever et al, 2013;Jungbluth et al, 2013), Atlantis Massif (Mason et al, 2010), North Pond (Orcutt et al, 2013), and Louisville Seamounts (Sylvan et al, 2015).…”

Expedition 390/393 Scientific Prospectus: The South Atlantic Transect

“…The majority of biological alteration of subseafloor basalts is thought to occur within 20 My of crustal formation (Bach and Edwards, 2003). However, microbiological investigations of oceanic basement have focused on young (<10 Ma) crust (Jungbluth et al, 2013;Lever et al, 2013;Mason et al, 2010;Orcutt et al, 2011) or older (>65 Ma) lava associated with hotspot volcanism along the Louisville seamount trail (Expedition 330 Scientists, 2012;Sylvan et al, 2015). Basement outcrops that penetrate the relatively impermeable sediment provide permeable conduits that facilitate subseafloor fluid circulation in older basement (Wheat and Fisher, 2008).…”

Rectinema subterraneum sp. nov, a chemotrophic spirochaete isolated from the deep terrestrial subsurface

“…Spores were searched for under phase contrast and scanning electron microscopes. Cultures were prepared for scanning electron microscopy with slight modifications from previously published methods [17,18]. Briefly, cells were fixed in a 2.5% formalin solution in sterile filtered PBS.…”