Oligotrophic Bacterium Research Articles

Effects of (p)ppGpp on the progression of the cell cycle of Caulobacter crescentus.

Bacteria must control the progression of their cell cycle in response to nutrient availability. This regulation can be mediated by guanosine tetra- or pentaphosphate [(p)ppGpp], which are synthesized by enzymes of the RelA/SpoT homologue (Rsh) family, particularly under starvation conditions. Here, we study the effects of (p)ppGpp on the cell cycle of Caulobacter crescentus, an oligotrophic bacterium with a dimorphic life cycle. C. crescentus divides asymmetrically, producing a motile swarmer cell that cannot replicate its chromosome and a sessile stalked cell that is replication competent. The swarmer cell rapidly differentiates into a stalked cell in appropriate conditions. An artificial increase in the levels of (p)ppGpp in nonstarved C. crescentus cells was achieved by expressing a truncated relA gene from Escherichia coli, encoding a constitutively active (p)ppGpp synthetase. By combining single-cell microscopy, flow cytometry approaches, and swarming assays, we show that an increase in the intracellular concentration of (p)ppGpp is sufficient to slow down the swarmer-to-stalked cell differentiation process and to delay the initiation of chromosome replication. We also present evidence that the intracellular levels of two master regulators of the cell cycle of C. crescentus, DnaA and CtrA, are modulated in response to (p)ppGpp accumulation, even in the absence of actual starvation. CtrA proteolysis and DnaA synthesis seem indirectly inhibited by (p)ppGpp accumulation. By extending the life span of the motile nonreproductive swarmer cell and thus promoting dispersal and foraging functions over multiplication under starvation conditions, (p)ppGpp may play a central role in the ecological adaptation of C. crescentus to nutritional stresses.

Sphingomonas oligoaromativorans sp. nov., an oligotrophic bacterium isolated from a forest soil

A halo- and organo-sensitive oligotrophic bacterium, designated strain SY-6T, was isolated from humus forest soil at Gyeryong mountain in Korea. Cells of the strain were Gram-negative, strictly aerobic, non-motile rods and the strain formed yellow-pigmented colonies on 100-fold-diluted nutrient broth. Strain SY-6T grew at pH 6.0-7.0 (optimal growth at pH 7.0), at 10-37 °C (optimal growth at 28 °C) and at salinities of 0-0.5% (w/v) NaCl, growing optimally at 0.01% (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, strain SY-6T was shown to belong to the genus Sphingomonas and showed the closest phylogenetic similarity to Sphingomonas polyaromaticivorans B2-7T (96.7%). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and sphingoglycolipid. The predominant ubiquinone and polyamine were Q-10 and sym-homospermidine, respectively. The major fatty acids were C18:1ω7c and C16:0. The DNA G+C content of the novel isolate was 65.3 mol%. On the basis of the evidence from this polyphasic study, strain SY-6T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas oligoaromativorans sp. nov. is proposed. The type strain is SY-6T (=KACC 12948T=NBRC 105508T).

Polymorphobacter multimanifer gen. nov., sp. nov., a polymorphic bacterium isolated from antarctic white rock

A Gram-stain-negative, non-spore-forming, aerobic, oligotrophic bacterium (strain 262-7(T)) was isolated from a crack of white rock collected in the Skallen region of Antarctica. Strain 262-7(T) grew at temperatures between -4 and 30 °C, with optimal growth at 25 °C. The pH range for growth was between pH 6.0 and 9.0, with optimal growth at approximately pH 7.0. The NaCl concentration range allowing growth was between 0.0 and 1.0%, with an optimum of 0.5%. Strain 262-7(T) showed an unprecedented range of morphological diversity in response to growth conditions. Cells grown in liquid medium were circular or ovoid with smooth surfaces in the lag phase. In the exponential phase, ovoid cells with short projections were observed. Cells in the stationary phase possessed long tentacle-like projections intertwined intricately. By contrast, cells grown on agar plate medium or in liquid media containing organic compounds at low concentration exhibited short- and long-rod-shaped morphology. These projections and morphological variations clearly differ from those of previously described bacteria. Ubiquinone 10 was the major respiratory quinone. The major fatty acids were C(17 : 1)ω6c (28.2%), C(16 : 1)ω7c (22.6%), C(18 : 1)ω7c (12.9%) and C(15 : 0) 2-OH (12.3%). The G+C content of genomic DNA was 68.0 mol%. Carotenoids were detected from the cells. Comparative analyses of 16S rRNA gene sequences indicated that strain 262-7(T) belongs to the family Sphingomonadaceae, and that 262-7(T) should be distinguished from known genera in the family Sphingomonadaceae. According to the phylogenetic position, physiological characteristics and unique morphology variations, strain 262-7(T) should be classified as a representative of a novel genus of the family Sphingomonadaceae. Here, a novel genus and species with the name Polymorphobacter multimanifer gen. nov., sp. nov. is proposed (type strain 262-7(T) = JCM 18140(T) = ATCC BAA-2413(T)). The novel species was named after its morphological diversity and formation of unique projections.

Characteristics and the Basic Kinetics of Ammonium Removal by Heterotrophic Nitrifying Bacteria at Low Temperature

A oligotrophic heterotrophic nitrifying bacterium Y21 was isolated from Songhua River at low temperature. The influence of temperature, pH, rotating speed of shaker as well as the carbon sources on the strain Y21 was investigated in this study. The experimental results showed that for the strain Y21, the optimum conditions were found to be temperature of 15 °C, pH of 7.4~8.2, shaking speed of 140 rmp respectively, with sodium acetate as carbon source. The strain Y21 has high activity under the culture condition at low temperature. The basic dynamic equation for the degradation of ammonia-nitrogen was obtained.

The dynamics of camphor in the cytochrome P450 CYP101D2

The recent crystal structures of CYP101D2, a cytochrome P450 protein from the oligotrophic bacterium Novosphingobium aromaticivorans DSM12444 revealed that both the native (substrate-free) and camphor-soaked forms have open conformations. Furthermore, two other potential camphor-binding sites were also identified from electron densities in the camphor-soaked structure, one being located in the access channel and the other in a cavity on the surface near the F-helix side of the F-G loop termed the substrate recognition site. These latter sites may be key intermediate positions on the pathway for substrate access to or product egress from the active site. Here, we show via the use of unbiased atomistic molecular dynamics simulations that despite the open conformation of the native and camphor-bound crystal structures, the underlying dynamics of CYP101D2 appear to be very similar to other CYP proteins. Simulations of the native structure demonstrated that the protein is capable of sampling many different conformational substates. At the same time, simulations with the camphor positioned at various locations within the access channel or recognition site show that movement towards the active site or towards bulk solvent can readily occur on a short timescale, thus confirming many previously reported in silico studies using steered molecular dynamics. The simulations also demonstrate how the fluctuations of an aromatic gate appear to control access to the active site. Finally, comparison of camphor-bound simulations with the native simulations suggests that the fluctuations can be of similar level and thus are more representative of the conformational selection model rather than induced fit.

Utilization of atmospheric ammonia by an extremely oligotrophic bacterium, Rhodococcus erythropolis N9T-4

Rhodococcus erythropolis N9T-4 shows extremely oligotrophic growth and requires CO2 for its growth. In this report, nitrogen sources for the oligotrophic growth of N9T-4 were examined. As is true for most other bacteria, N9T-4 preferred ammonium salt to nitrate as the nitrogen source on an inorganic minimum medium without carbon sources. Interestingly, N9T-4 could also grow on the minimal medium solidified by agarose or silica gel without carbon and nitrogen sources, suggesting that this bacterium is also oligotrophic for nitrogen. We can rule out the possibility of diazotrophic growth of this bacterium, because nitrogenase activity was not detected in the cells and the putative gene encoding nitrogenase was not found in N9T-4 genome. DNA microarray analysis revealed that one of the ammonium transporter genes (amtB) was strongly upregulated 40-50 fold higher under oligotrophic conditions than under heterotrophic conditions. Disruption of amtB led to a growth defect under nitrogen-limiting conditions. Furthermore, additional ammonia vapor enhanced the growth of N9T-4 on the minimum medium without nitrogen sources in a closed culture system. These results suggest that N9T-4 utilizes the trace amount of atmospheric ammonia as the nitrogen source.

Spirosoma xylofaga sp. nov., an oligotrophic pleomorphic bacterium from a myco-bacterial community of freshwater ecosystems

A novel aerobic bacterial strain Z-0088 was assigned to the genus Spirosoma on the basis of 16S rRNA analysis; it was isolated from a bacterial community of moderately acidic (pH 5.0) dystrophic, slightly humified water formed by xylotrophic fungi grown on decaying spruce wood. The cells are nonmotile, gramnegative, straight or curved rods, 0.5–1.5 × 1.0–6.0 μm; they may also be toroidal. The cells are usually single but can form spiral filaments containing from 4 to 13 coils; their reproduction is by division. Strain Z-0088 is an organoheterotroph utilizing xylan, inulin, xylose, sucrose, and N-acetylglucosamine as organic growth substrates. The bacterium is oligotrophic (the optimum substrate concentration is 0.5 g/L). It is characterized by high sensitivity to NaCl concentration; growth was completely suppressed at 1% NaCl. The strain grows in a pH range of 3.8–7.5 with the optimum at pH 5.5–6.5. The temperature range for growth was 13–35°C with the optimum at 28°C. The DNA G+C base content was 50.2 mol %. The ecophysiological features of strain Z-0088, such as oligotrophic, mesophilic, moderate acidophilic properties, and sensitivity to NaCl, support its designation as a representative of ombrophilic dissipotrophs. The strain is assigned to a novel species Spirosoma xylofaga sp. nov.

Interaction of Collimonas strain IS343 with Rhizoctonia solani at low carbon availability in vitro and in soil

Collimonas sp. IS343, isolated from an organically-farmed arable soil and characterized as a broad-range oligotrophic bacterium, was shown to degrade chitin and to suppress R. solani mycelium growth under in vitro conditions at high and low carbon availabilities. In contrast to C. fungivorans Ter331, strain IS343 did not respond with an increase in growth rate to higher carbon levels in liquid medium, it reached higher cell numbers in carbon-poor media and it showed better survival in bulk soil. Therefore, it was concluded that strain IS343 cells are better adapted to circumstances of low carbon availability as present in bulk soils than strain Ter331 cells. Further, strain IS343 cells were more suppressive towards R. solani than strain Ter331 cells in vitro. When introduced into soil, strain IS343 cells delayed disease development caused by R. solani AG2-2IIIB in sugar beet plants. These results suggest that strain IS343 cells are able to tentatively suppress R. solani AG2-2IIIB mycelium growth in soil. Potential mechanisms behind the observed suppressive effects can be competition for available nutrients between strain IS343 cells and R. solani mycelium in soil or the production of chitinase as shown for this and other Collimonas species.

The xylan utilization system of the plant pathogen Xanthomonas campestris pv campestris controls epiphytic life and reveals common features with oligotrophic bacteria and animal gut symbionts

Xylan is a major structural component of plant cell wall and the second most abundant plant polysaccharide in nature. Here, by combining genomic and functional analyses, we provide a comprehensive picture of xylan utilization by Xanthomonas campestris pv campestris (Xcc) and highlight its role in the adaptation of this epiphytic phytopathogen to the phyllosphere. The xylanolytic activity of Xcc depends on xylan-deconstruction enzymes but also on transporters, including two TonB-dependent outer membrane transporters (TBDTs) which belong to operons necessary for efficient growth in the presence of xylo-oligosaccharides and for optimal survival on plant leaves. Genes of this xylan utilization system are specifically induced by xylo-oligosaccharides and repressed by a LacI-family regulator named XylR. Part of the xylanolytic machinery of Xcc, including TBDT genes, displays a high degree of conservation with the xylose-regulon of the oligotrophic aquatic bacterium Caulobacter crescentus. Moreover, it shares common features, including the presence of TBDTs, with the xylan utilization systems of Bacteroides ovatus and Prevotella bryantii, two gut symbionts. These similarities and our results support an important role for TBDTs and xylan utilization systems for bacterial adaptation in the phyllosphere, oligotrophic environments and animal guts.

Genome Analysis Suggests that the Soil Oligotrophic Bacterium Agromonas oligotrophica (Bradyrhizobium oligotrophicum) Is a Nitrogen-Fixing Symbiont of Aeschynomene indica

Agromonas oligotrophica (Bradyrhizobium oligotrophicum) S58(T) is a nitrogen-fixing oligotrophic bacterium isolated from paddy field soil that is able to grow in extra-low-nutrient environments. Here, the complete genome sequence of S58 was determined. The S58 genome was found to comprise a circular chromosome of 8,264,165 bp with an average GC content of 65.1% lacking nodABC genes and the typical symbiosis island. The genome showed a high level of similarity to the genomes of Bradyrhizobium sp. ORS278 and Bradyrhizobium sp. BTAi1, including nitrogen fixation and photosynthesis gene clusters, which nodulate an aquatic legume plant, Aeschynomene indica, in a Nod factor-independent manner. Although nonsymbiotic (brady)rhizobia are significant components of rhizobial populations in soil, we found that most genes important for nodule development (ndv) and symbiotic nitrogen fixation (nif and fix) with A. indica were well conserved between the ORS278 and S58 genomes. Therefore, we performed inoculation experiments with five A. oligotrophica strains (S58, S42, S55, S72, and S80). Surprisingly, all five strains of A. oligotrophica formed effective nitrogen-fixing nodules on the roots and/or stems of A. indica, with differentiated bacteroids. Nonsymbiotic (brady)rhizobia are known to be significant components of rhizobial populations without a symbiosis island or symbiotic plasmids in soil, but the present results indicate that soil-dwelling A. oligotrophica generally possesses the ability to establish symbiosis with A. indica. Phylogenetic analyses suggest that Nod factor-independent symbiosis with A. indica is a common trait of nodABC- and symbiosis island-lacking strains within the members of the photosynthetic Bradyrhizobium clade, including A. oligotrophica.

Regulation of D-galacturonate metabolism in <i>Caulobacter crescentus</i> by HumR, a LacI-family transcriptional repressor

The oligotrophic freshwater bacterium Caulobacter crescentus encodes a cluster of genes (CC_1487 to CC_1495) shown here to be necessary for metabolism of D-galacturonate, the primary constituent of pectin, a major plant polymer. Sequence analysis suggests that these genes encode a version of the bacterial hexuronate isomerase pathway. A conserved 14 bp sequence motif is associated with promoter regions of three operons within this cluster, and is conserved in homologous gene clusters in related alpha-Proteobacteria. Embedded in the hexuronate gene cluster is a gene (CC_1489) encoding a member of the LacI family of bacterial transcription factors. This gene product, designated here as HumR (hexuronate metabolism regulator), represses expression of the uxaA and uxaC operon promoters by binding to the conserved operator sequence. Repression is relieved in the presence of galacturonate or, to a lesser extent, by glucuronate. Other genes potentially involved in pectin degradation and hexuronate transport are also under the control of HumR. Adoption of a LacI-type repressor to control hexuronate metabolism parallels the regulation of xylose, glucose, and maltose utilization in C. crescentus, but is distinct from the use of GntR-type repressors to control pectin and hexuronate utilization in gamma-Proteobacteria such as Escherichia coli.

Carbon monoxide utilization of an extremely oligotrophic bacterium, Rhodococcus erythropolis N9T-4

CO utilization by a CO(2)-requiring extremely oligotrophic bacterium, Rhodococcus erythropolis N9T-4 was found when CO(2) was removed from the culture environment before cultivation, suggesting that this bacterium can convert CO into CO(2). However, the gene encoding putative CO dehydrogenase large subunit in N9T-4 was not induced by CO.

Investigation of unusual growth and phenotypic characteristics of plasmid-containing and plasmid-free strains of oligotrophic bacterium Ancylobacter vacuolatus

The oligotrophic bacterium Ancylobacter vacuolatus contains two large plasmids pREV1 and pREV2 (about 150 and 250 kb, respectively). Plasmid pREV1 carries the genes responsible for resistance to chloramphenicol, trimethoprim and y-irradiation. Plasmid pREV2 carries the genes responsible for resistance to beta-lactam antibiotics and formation of gas vacuoles. The ability to grow under oligotrophic conditions did not depend directly on either plasmid and was probably chromosome-encoded. Nevertheless, strains lacking the pREV2 plasmid had an improved capacity for growth in enriched media, as is evident from the following findings: 1) the growth rate of the strains lacking pREV2 was about 60% higher with an induction time of about two times less than those for strains carrying the plasmid; 2) the overall cell yield in rich media and colony size on non-oligotrophic agarized media increased with removal of pREV2; 3) the characteristic change in cell morphology occurring in the wild type ofA. vacuolatus when switched from oligotrophic to eutrophic growth conditions was not observed in the strains lacking pREV2; 4) bacterial strains lacking pREV2 exhibited significantly higher rRNA content than the parent strain. As a possible explanation for these phenomena, we suggest that the pREV2 plasmid carries gene(s) for protein(s) acting as repressor(s) of expression of some enzymes involved in eutrophic metabolism. Such protein(s) probably participate in switching between the oligotrophic and eutrophic types of metabolism in response to changing nutrient supply in the environment.

Crystallization and preliminary X-ray analysis of CYP153C1 from Novosphingobium aromaticivorans DSM12444.

Cytochrome P450 (CYP) enzymes constitute a large family of haemoproteins that catalyze the monooxygenation of a great variety of endogenous and exogenous organic compounds. In common with other members of the CYP153 family of alkane hydroxylases, CYP153C1 from the oligotrophic bacterium Novosphingobium aromaticivorans DSM 12444 can bind linear alkanes such as heptane, octane and nonane. Here, the production, purification and crystallization of CYP153C1 and the collection of high-resolution diffraction data to 1.77 Å resolution are reported. The crystals belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 61.0, b = 96.3, c = 149.8 Å, α = β = γ = 90.0°. Preliminary X-ray diffraction data analysis revealed that the asymmetric unit is most likely to contain two protein molecules.

Molecular Characterization of a Class I P450 Electron Transfer System from Novosphingobium aromaticivorans DSM12444

Cytochrome P450 (CYP) enzymes of the CYP101 and CYP111 families from the oligotrophic bacterium Novosphingobium aromaticivorans DSM12444 are heme monooxygenases that receive electrons from NADH via Arx, a [2Fe-2S] ferredoxin, and ArR, a ferredoxin reductase. These systems show fast NADH turnovers (k(cat) = 39-91 s(-1)) that are efficiently coupled to product formation. The three-dimensional structures of ArR, Arx, and CYP101D1, which form a physiological class I P450 electron transfer chain, have been resolved by x-ray crystallography. The general structural features of these proteins are similar to their counterparts in other class I systems such as putidaredoxin reductase (PdR), putidaredoxin (Pdx), and CYP101A1 of the camphor hydroxylase system from Pseudomonas putida, and adrenodoxin (Adx) of the mitochondrial steroidogenic CYP11 and CYP24A1 systems. However, significant differences in the proposed protein-protein interaction surfaces of the ferredoxin reductase, ferredoxin, and P450 enzyme are found. There are regions of positive charge on the likely interaction face of ArR and CYP101D1 and a corresponding negatively charged area on the surface of Arx. The [2Fe-2S] cluster binding loop in Arx also has a neutral, hydrophobic patch on the surface. These surface characteristics are more in common with those of Adx than Pdx. The observed structural features are consistent with the ionic strength dependence of the activity.

Discussion on the Appropriate Nutritional Conditions for the Extracellular Viscous Materials of an Oligotrophic Bacterium

This paper discusses the effects of the several different carbon sources,nitrogen sources,inorganic salt content and oxygen on the extracellular viscous materials of an oligotrophic bacterium with the single-factor optimization method.The results show that the appropriate conditions of secreting the viscous materials from the bacterial strain are to use sucrose as the carbon source(15 mg C/L) without any N sources,CaCO_3 content of 2 g/L, KH_2PO_4 content of 0.3 g/L,MgSO_4 content of 0.05 g/L,NaCl content of 5～10 g/L,and pH value of 7.0.A medium of 50 mL at pH 7.0 was poured to a flask of 250 mL.After the Sterilization and inoculation,culture solution was shaken for 60 hours at 37℃.The viscosity of culture solution could be up to 9 000 mPa·s.The viscosity was increased by 15%under the same culture time compared with that before optimizing.Such optimization conditions can be directly used to produce the first-class germ of the artificial biotic crust.

SpoT Regulates DnaA Stability and Initiation of DNA Replication in Carbon-StarvedCaulobacter crescentus

Cell cycle progression and polar differentiation are temporally coordinated in Caulobacter crescentus. This oligotrophic bacterium divides asymmetrically to produce a motile swarmer cell that represses DNA replication and a sessile stalked cell that replicates its DNA. The initiation of DNA replication coincides with the proteolysis of the CtrA replication inhibitor and the accumulation of DnaA, the replication initiator, upon differentiation of the swarmer cell into a stalked cell. We analyzed the adaptive response of C. crescentus swarmer cells to carbon starvation and found that there was a block in both the swarmer-to-stalked cell polar differentiation program and the initiation of DNA replication. SpoT is a bifunctional synthase/hydrolase that controls the steady-state level of the stress-signaling nucleotide (p)ppGpp, and carbon starvation caused a SpoT-dependent increase in (p)ppGpp concentration. Carbon starvation activates DnaA proteolysis (B. Gorbatyuk and G. T. Marczynski, Mol. Microbiol. 55:1233-1245, 2005). We observed that SpoT is required for this phenomenon in swarmer cells, and in the absence of SpoT, carbon-starved swarmer cells inappropriately initiated DNA replication. Since SpoT controls (p)ppGpp abundance, we propose that this nucleotide relays carbon starvation signals to the cellular factors responsible for activating DnaA proteolysis, thereby inhibiting the initiation of DNA replication. SpoT, however, was not required for the carbon starvation block of the swarmer-to-stalked cell polar differentiation program. Thus, swarmer cells utilize at least two independent signaling pathways to relay carbon starvation signals: a SpoT-dependent pathway mediating the inhibition of DNA replication initiation, and a SpoT-independent pathway(s) that blocks morphological differentiation.

A simple and easy method for the monitoring of environmental pollutants using oligotrophic bacteria

Y. TADA, T. KOBATA AND C. NAKAOKA. 2001. Sphingomonas paucimobilis KPS01, an oligotrophic bacterium isolated from soil, may be a useful tool for monitoring heavy metals. Previous methods relying on counting of viable cells require a relatively long time and some skill; we have developed a method based on optical density (O.D.) measurements which is significantly faster and does not require skilled personnel. The results of the O.D. and viable count methods were consistent; both methods detected heavy metals at concentrations ranging from 10−3 to 10−5 mmol l−1 and identified heavy metal contamination in 13 of 18 river water samples. Our results demonstrate that biological detection using this O.D. method and S. paucimobilis KPS01 may be useful for routine environmental monitoring of heavy metals, particularly in water sources.

A study on an oligotrophic bacteria and its ecological characteristics in an arid desert area

An oligotrophic bacterium was isolated from the biological soil crust underlayer in the Xinjiang Gurbantunggut Desert. It was numbered SGB-5, G+. Cell size is (0.328–0.746) μm×(0.171–0.240) μm. Raised colony is white, roundness and its diameter is 5 mm. The strain is a facultative aerobe. It was able to grow in conditions of 1–15 mg·C·L−1 culture medium at 10–50°C. The strain’s optimum growth temperature is 37°C. The range of its optimum growth pH is 8–9. A large amount of extracellular mucopolysaccharide was secreted during growth. The chemical composition of this mucopolysaccharide consists of arabinose, X sugar, glucose, galactose and mannitol. Mole ratio of these sugars is 1:14:19:6:14. The viscosity of the mucopolysaccharide can reach 6300 mPa·s, when the strain is cultivated for 72 h. After the culture solution in which viscosity was 1500 mPa·s was sprinkled on the quicksand surface, 6 mm bacteria crust of conglutinating sand was formed. This crust could not only stabilize sand, but could also potentially slow the rate of the soil water evaporation.

Sphingomonas oligophenolica sp. nov., a halo- and organo-sensitive oligotrophic bacterium from paddy soil that degrades phenolic acids at low concentrations

The taxonomic position of a halo- and organo-sensitive, oligotrophic soil bacterium, strain S213(T), was investigated. Cells were Gram-negative, non-motile, strictly aerobic, yellow-pigmented rods of short to medium length on diluted nutrient broth. When 0.1-0.4 % (w/v) NaCl was added to diluted media composed of peptone and meat extract, growth was inhibited with increasing NaCl concentration and the cells became long aberrant forms. When 6 mM CaCl(2) was added, the cells grew quite normally and aberrant cells were no longer found at 0.1-0.5 % (w/v) NaCl. Chemotaxonomically, strain S213(T) contains chemical markers that indicate its assignment to the Sphingomonadaceae: the presence of ubiquinone Q-10 as the predominant respiratory quinone, C(18 : 1) and C(16 : 0) as major fatty acids, C(14 : 0) 2-OH as the major 2-hydroxy fatty acid and sphingoglycolipids. 16S rRNA gene sequence analysis indicated that strain S213(T) belongs to the genus Sphingomonas, exhibiting high sequence similarity to the 16S rRNA gene sequences of Sphingomonas mali IFO 15500(T) (98.3 %), Sphingomonas pruni IFO 15498(T) (98.0 %), Sphingomonas asaccharolytica IFO 15499(T) (97.9 %) and Sphingomonas echinoides DSM 1805(T) (97.8 %). The results of DNA-DNA hybridization experiments and its phenotypic characteristics clearly distinguished the strain from its nearest neighbours and demonstrate that strain S213(T) represents a novel Sphingomonas species, for which the name Sphingomonas oligophenolica sp. nov. is proposed. The type strain is S213(T) (=JCM 12082(T)=CIP 107926(T)).