title: Isolation and characterization of soil bacteria that define Terriglobus gen. nov., in the phylum Acidobacteria.
abstract: Bacteria in the phylum Acidobacteria are widely distributed and abundant in soils, but their ecological roles are poorly understood, owing in part to a paucity of cultured representatives. In a molecular survey of acidobacterial diversity at the Michigan State University Kellogg Biological Station Long-Term Ecological Research site, 27% of acidobacterial 16S rRNA gene clones in a never-tilled, successional plant community belonged to subdivision 1, whose relative abundance varied inversely with soil pH. Strains of subdivision 1 were isolated from these never-tilled soils using low-nutrient medium incubated for 3 to 4 weeks under elevated levels of carbon dioxide, which resulted in a slightly acidified medium that matched the pH optima of the strains (between 5 and 6). Colonies were approximately 1 mm in diameter and either white or pink, the latter due to a carotenoid(s) that was synthesized preferentially under 20% instead of 2% oxygen. Strains were gram-negative, aerobic, chemo-organotrophic, nonmotile rods that produced an extracellular matrix. All strains contained either one or two copies of the 16S rRNA encoding gene, which along with a relatively slow doubling time (10 to 15 h at ca. 23 degrees C) is suggestive of an oligotrophic lifestyle. Six of the strains are sufficiently similar to one another, but distinct from previously named Acidobacteria, to warrant creation of a new genus, Terriglobus, with Terriglobus roseus defined as the type species. The physiological and nutritional characteristics of Terriglobus are consistent with its potential widespread distribution in soil.
authors.affiliation: Michigan State University, Department of Microbiology and Molecular Genetics, 6180 Biomedical and Physical Sciences Building, East Lansing, MI 48824-4320, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Eichorst
authors.forename: John A
authors.initials: JA
authors.lastname: Breznak
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Schmidt
mesh_terms: D015373:Bacterial Typing Techniques; D015139:Blotting, Southern; D002244:Carbon / Q000378:metabolism; D002338:Carotenoids / Q000096:biosynthesis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005109:Extracellular Matrix; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D020459:Genes, rRNA / Q000235:genetics; D016946:Gram-Negative Aerobic Rods and Cocci / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification* / Q000502:physiology; D008969:Molecular Sequence Data; D009068:Movement; D010802:Phylogeny; D010860:Pigments, Biological / Q000096:biosynthesis; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D010860:Pigments, Biological; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D002338:Carotenoids; D002244:Carbon