TY - JOUR
T1 - Sphingomonas alaskensis Strain AFO1, an Abundant Oligotrophic Ultramicrobacterium from the North Pacific
AU - Eguchi, Mitsuru
AU - Ostrowski, Martin
AU - Fegatella, Fitri
AU - Bowman, John
AU - Nichols, David
AU - Nishino, Tomohiko
AU - Cavicchioli, Ricardo
PY - 2001
Y1 - 2001
N2 - Numerous studies have established the importance of picoplankton (microorganisms of ≤2 μ,m in length) in energy flow and nutrient cycling in marine oligotrophic environments, and significant effort has been directed at identifying and isolating heterotrophic picoplankton from the world's oceans. Using a method of diluting natural seawater to extinction followed by monthly subculturing for 12 months, a bacterium was isolated that was able to form colonies on solid medium. The strain was isolated from a 105 dilution of seawater where the standing bacterial count was 3.1 × 105 cells ml-1. This indicated that the isolate was representative of the most abundant bacteria at the sampling site, 1.5 km from Cape Muroto, Japan. The bacterium was characterized and found to be ultramicrosized (less than 0.1 μm3), and the size varied to only a small degree when the cells were starved or grown in rich media. A detailed molecular (16S rRNA sequence, DNA-DNA hybridization, G+C mol%, genome size), chemotaxonomic (lipid analysis, morphology), and physiological (resistance to hydrogen peroxide, heat, and ethanol) characterization of the bacterium revealed that it was a strain of Sphingomonas alaskensis. The type strain, RB2256, was previously isolated from Resurrection Bay, Alaska, and similar isolates have been obtained from the North Sea. The isolation of this species over an extended period, its high abundance at the time of sampling, and its geographical distribution indicate that it has the capacity to proliferate in ocean waters and is therefore likely to be an important contributor in terms of biomass and nutrient cycling in marine environments.
AB - Numerous studies have established the importance of picoplankton (microorganisms of ≤2 μ,m in length) in energy flow and nutrient cycling in marine oligotrophic environments, and significant effort has been directed at identifying and isolating heterotrophic picoplankton from the world's oceans. Using a method of diluting natural seawater to extinction followed by monthly subculturing for 12 months, a bacterium was isolated that was able to form colonies on solid medium. The strain was isolated from a 105 dilution of seawater where the standing bacterial count was 3.1 × 105 cells ml-1. This indicated that the isolate was representative of the most abundant bacteria at the sampling site, 1.5 km from Cape Muroto, Japan. The bacterium was characterized and found to be ultramicrosized (less than 0.1 μm3), and the size varied to only a small degree when the cells were starved or grown in rich media. A detailed molecular (16S rRNA sequence, DNA-DNA hybridization, G+C mol%, genome size), chemotaxonomic (lipid analysis, morphology), and physiological (resistance to hydrogen peroxide, heat, and ethanol) characterization of the bacterium revealed that it was a strain of Sphingomonas alaskensis. The type strain, RB2256, was previously isolated from Resurrection Bay, Alaska, and similar isolates have been obtained from the North Sea. The isolation of this species over an extended period, its high abundance at the time of sampling, and its geographical distribution indicate that it has the capacity to proliferate in ocean waters and is therefore likely to be an important contributor in terms of biomass and nutrient cycling in marine environments.
UR - http://www.scopus.com/inward/record.url?scp=0035515422&partnerID=8YFLogxK
M3 - Article
C2 - 11679312
AN - SCOPUS:0035515422
SN - 0099-2240
VL - 67
SP - 4945
EP - 4954
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 3-12
ER -