Interaction Between Chronic Endometritis Caused Endometrial Microbiota Disorder and Endometrial Immune Environment Change in Recurrent Implantation Failure.

Objective: To investigate the Interaction between chronic endometritis (CE) caused endometrial microbiota disorder and endometrial immune environment change in recurrent implantation failure (RIF). Method: Transcriptome sequencing analysis of the endometrial of 112 patients was preform by using High-Throughput Sequencing. The endometrial microbiota of 43 patients was analyzed by using 16s rRNA sequencing technology. Result: In host endometrium, CD4 T cell and macrophage exhibited significant differences abundance between CE and non-CE patients. The enrichment analysis indicated differentially expressed genes mainly enriched in immune-related functional terms. Phyllobacterium and Sphingomonas were significantly high infiltration in CE patients, and active in pathways related to carbohydrate metabolism and/or fat metabolism. The increased synthesis of lipopolysaccharide, an important immunomodulator, was the result of microbial disorders in the endometrium. Conclusion: The composition of endometrial microorganisms in CE and non-CE patients were significantly different. Phyllobacterium and Sphingomonas mainly regulated immune cells by interfering with the process of carbohydrate metabolism and/or fat metabolism in the endometrium. CE endometrial microorganisms might regulate Th17 response and the ratio of Th1 to Th17 through lipopolysaccharide (LPS).

Induction of Apoptosis in Human Lung Epithelial Cell by Sphingomonas sp. Shah, a Recently Identified Cell Culture Contaminant.

Sphingomonas sp. Shah is a bacterium that was first isolated from mammalian cell cultures. According to ribotyping data it is very much homologous to the clinically important pathogen Sphingomonas paucimobilis, which has generated pseudo-outbreaks. Using a tissue culture system, Sphingomonas sp. Shah was discovered to induce apoptosis in human lung epithelial carcinoma. Apoptosis of infected cells was determined by numerous criteria including (1) visual alterations in cellular morphology, (2) initiation of nuclear marginalization and chromatin compaction condensation, (3) the attendance of a high percentage of cells with subG1 DNA content, and (4) caspase-3 activation. In the current study we demonstrate the induction of apoptosis in mammalian lung epithelial cells upon infection with Sphingomonas sp. Shah and provide insight into the molecular processes triggering apoptosis.

Comprehensive Genome Analysis on the Novel Species Sphingomonas panacis DCY99T Reveals Insights into Iron Tolerance of Ginseng.

Plant growth-promoting rhizobacteria play vital roles not only in plant growth, but also in reducing biotic/abiotic stress. Sphingomonas panacis DCY99T is isolated from soil and root of Panax ginseng with rusty root disease, characterized by raised reddish-brown root and this is seriously affects ginseng cultivation. To investigate the relationship between 159 sequenced Sphingomonas strains, pan-genome analysis was carried out, which suggested genomic diversity of the Sphingomonas genus. Comparative analysis of S. panacis DCY99T with Sphingomonas sp. LK11 revealed plant growth-promoting potential of S. panacis DCY99T through indole acetic acid production, phosphate solubilizing, and antifungal abilities. Detailed genomic analysis has shown that S. panacis DCY99T contain various heavy metals resistance genes in its genome and the plasmid. Functional analysis with Sphingomonas paucimobilis EPA505 predicted that S. panacis DCY99T possess genes for degradation of polyaromatic hydrocarbon and phenolic compounds in rusty-ginseng root. Interestingly, when primed ginseng with S. panacis DCY99T during high concentration of iron exposure, iron stress of ginseng was suppressed. In order to detect S. panacis DCY99T in soil, biomarker was designed using spt gene. This study brings new insights into the role of S. panacis DCY99T as a microbial inoculant to protect ginseng plants against rusty root disease.

The endophytic bacterium Sphingomonas SaMR12 alleviates Cd stress in oilseed rape through regulation of the GSH-AsA cycle and antioxidative enzymes.

BACKGROUND: Microbes isolated from hyperaccumulating plants have been reported to be effective in achieving higher phytoextraction efficiency. The plant growth-promoting bacteria (PGPB) SaMR12 from the cadmium (Cd)/zinc hyperaccumulator Sedum alfredii Hance could promote the growth of a non-host plant, oilseed rape, under Cd stress. However, the effect of SaMR12 on Brasscia juncea antioxidative response under Cd exposure was still unclear. RESULTS: A hydroponic experiment was conducted to study the effects of Sphingomonas SaMR12 on its non-host plant Brassica juncea (L.) Czern. under four different Cd treatments. The results showed that SaMR12 could colonize and aggregate in the roots and then move to the shoots. SaMR12 inoculation promoted plant growth by up to 71% in aboveground biomass and 81% in root biomass over that of the non-inoculated plants. SaMR12-inoculated plants significantly enhanced root Cd accumulation in the 10 and 20 µM Cd treatments, with 1.72- and 0.86-fold increases, respectively, over that of the non-inoculated plants. SaMR12 inoculation not only decreased shoot hydrogen peroxide (H2O2) content by up to 38% and malondialdehyde (MDA) content by up to 60% but also reduced proline content by 7-30% in shoots and 17-32% in roots compared to the levels in non-inoculated plants. Additionally, SaMR12 inoculation promoted the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and facilitated the relative gene expression levels of dehydroascorbate reductase (DHAR) and glutathione reductase (GR) involved in the glutathione (GSH)-ascorbic acid (AsA) cycle. CONCLUSIONS: The results demonstrated that, under Cd stress, SaMR12 inoculation could activate the antioxidative response of B. juncea by decreasing the concentrations of H2O2, MDA and proline, increasing the activities of antioxidative enzymes, and regulating the GSH-AsA cycle. These results provide a theoretical foundation for the potential application of hyperaccumulator endophytic bacteria as remediating agents to improve heavy metal tolerance within non-host plant species, which could further improve phytoextraction efficiency.

Biofilm forming ability of Sphingomonas paucimobilis isolated from community drinking water systems on plumbing materials used in water distribution.

Sphingomonas paucimobilis, an oligotroph, is well recognized for its potential for biofilm formation. The present study explored the biofilm forming ability of a strain isolated from municipal drinking water on plumbing materials. The intensity of biofilm formation of this strain on different plumbing materials was examined by using 1 × 1 cm2 pieces of six different pipe materials, i.e. polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), aluminium (Al), copper (Cu) and rubber (R) and observing by staining with the chemical chromophore, Calcofluor. To understand whether biofilm formation occurs under flow through conditions, a laboratory-scale simulated distribution system, comprised of the above materials was fabricated. Biofilm samples were collected from the designed system at different biofilm ages (10, 40 and 90 hours old) and enumerated. The results indicated that the biofilm formation occurred on all plumbing materials with Cu and R as exceptions. The intensity of biofilm formation was found to be maximum on PVC followed by PP and PE. We also demonstrated the chemical chromophore (Calcofluor) successfully for rapid and easy visual detection of biofilms, validated by scanning electron microscope (SEM) analysis of the plumbing materials. Chlorination has little effect in preventing biofilm development.

Sphingomonas arantia sp. nov., isolated from Hoh Xil basin, China.

A Gram-negative, rod-shaped, non-motile, non-spore forming, aerobic, orange-pigmented bacterium, designated strain 6P(T), was isolated from a soil sample collected from the Hoh Xil basin, China. Strain 6P(T) grew optimally at 25 °C, pH 7.0-7.5 and NaCl concentration of 0-1 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 6P(T) belongs to the genus Sphingomonas, with high sequence similarity (97.1 %) to Sphingomonas fennica. The DNA-DNA hybridization homology with S. fennica DSM 13665(T) was 45.3 %. The DNA G+C content of the novel strain is 65.3 mol%. The isolate contained Q-10 as the only respiratory quinone. The major polar lipids are diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylcholine (PC) and sphingoglycolipid (SGL). C18:1 ω7c and C16:1 ω7c are the major fatty acids. On the basis of the polyphasic evidence presented, strain 6P(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas arantia sp. nov. is proposed. The type strain is 6P(T) (=CGMCC 1.12702(T) = JCM 19855(T)).

Sphingomonas kyeonggiense sp. nov., isolated from soil of a ginseng field.

A Gram-staining negative bacterium, THG-DT81(T), which was isolated from soil of a ginseng field, was investigated using a polyphasic taxonomic approach. Cells were oxidase- and catalase-positive, aerobic, rod-shaped and motile with one polar flagellum. Strain THG-DT81(T) grew optimally at pH 7.0 and in the absence of NaCl on trypticase soy agar. Its optimum growth temperature was 25-28 °C. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain THG-DT81(T) belongs to the family Sphingomonadaceae and was related to Sphingomonas pituitosa EDIV(T) (98.0 % similarity), S. leidyi ATCC 15260(T) (97.8 %), S. trueperi LMG 2142(T) (97.1 %), S. azotifigens NBRC 15497(T) (97.1 %), S. koreensis JSS26 (T) (97.1 %) and S. dokdonensis DS-4(T) (97.0 %). Strain THG-DT81(T) contained Q-10 as the predominant ubiquinone and C18:1 ω7c and C16:0 as the major fatty acids. The G+C content of the genomic DNA was determined to be 66.8 mol %. The major component in the polyamine pattern was identified as sym-homospermidine. The major polar lipids detected in strain THG-DT81(T) were sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. The DNA-DNA relatedness values of the strain THG-DT81(T) and its closest phylogenetically neighbors were below 21 %. The phenotypic characteristics and genotypic data demonstrated the affiliation of strain THG-DT81(T) to the genus Sphingomonas. On the basis of the polyphasic taxonomic data presented, strain THG-DT81(T) is described as a novel species of genus Sphingomonas, for which the name Sphingomonas kyeonggiense sp. nov. is proposed. The type strain is THG-DT81(T) (= KACC 17173(T) = JCM 18825(T)).

Postpartum fever in the presence of a fibroid: Sphingomonas paucimobilis sepsis associated with pyomyoma.

BACKGROUND: Pyomyoma is a life-threatening complication of uterine leiomyoma. It may occur in post- menopausal women, during pregnancy and in the postpartum period. Fever may be the only manifestation during the early stages of the disease. We detail the first reported case of postpartum pyomyoma-related sepsis due to Sphingomonas paucimobilis, a Gram-negative bacillus that is gaining recognition as an important human pathogen. CASE PRESENTATION: A woman presented with an asymptomatic uterine fibroid and a two-week history of fever during the postpartum period. Suppurative uterine leiomyoma was diagnosed, and blood cultures grew Sphingomonas paucimobilis. The myoma was surgically removed from the uterus without hysterectomy. Intravenous antimicrobial therapy was given for fifteen days, and the patient was discharged from hospital in good condition. CONCLUSION: Pyomyoma should be considered in broad differential diagnosis of postpartum fever. This case highlights a unique disease manifestation of S. paucimobilis, an emerging opportunistic pathogen with increasing significance in the nosocomial setting.

Sphingomonas jejuensis sp. nov., isolated from marine sponge Hymeniacidon flavia.

A Gram-negative, non-motile, rod shaped, and orange-pigmented chemoheterotrophic bacterium, strain MS-31(T) was isolated from the marine sponge Hymeniacidon flavia, collected from near Jeju Island, Korea. The Strain MS-31(T) was subjected to a polyphasic taxonomic study. The phylogenetic analysis based on the 16S rRNA gene sequences revealed that the novel isolate could be affiliated within the genus Sphingomonas. The strain MS-31(T) showed 95.6% of 16S rRNA gene sequence similarity with the most closely related species Sphingomonas koreensis JSS26(T). The DNA G+C content of the strain MS-31(T) was 69.4 mol%. The major isoprenoid quinone was ubiqunone 10 and predominant cellular fatty acids were summed feature 7 (comprising C(18:1) ω7c, C(18:1) Ω9t and/or C(18:1) ωl2t, 39.7%), C(16:0) (16.3%), C(14:0) 2OH (15.9%) and summed feature 3 (comprising C(16:1) ω7c and/or C(15:0) iso 2OH, 11.7%). The polar lipids were sphingoglycolipid, phosphatidyletha-nolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified glycolipid. Based on the evidence from the polyphasic taxonomic study, the strain should be classified as a new species of the genus Sphingomonas. As a result, the name Sphingomonas jejuensis sp. nov. (type strain MS-31(T) =KCTC 23321(T) =NBRC 107775(T)) is proposed.

Sphingomonas histidinilytica sp. nov., isolated from a hexachlorocyclohexane dump site.

A Gram-negative, non-spore-forming, cream-coloured bacterial strain, UM2(T), was isolated from an open hexachlorocyclohexane (HCH) dump site at Ummari village in Lucknow, India. Data generated from a polyphasic approach including phenotypic, genotypic and chemotaxonomic analyses confirmed that strain UM2(T) belonged to the genus Sphingomonas. The highest similarity found to the 16S rRNA gene sequence of strain UM2(T) was 99.4 %, with Sphingomonas wittichii DSM 6014(T), whereas the DNA-DNA relatedness value between these strains was 31 %, indicating that they represent separate species. The DNA G+C content of UM2(T) was 66.9 mol%. The respiratory pigment ubiquinone Q-10 was present. The predominant fatty acids were summed feature 8 (C(18 : 1)omega6c and/or C(18 : 1)omega7c; 32.9 %), C(19 : 0) cyclo omega8c (15.5 %) and C(16 : 0) (12.1 %). The major polar lipids were phosphatidylcholine, phosphatidylglycerol and phosphatidyldimethylethanolamine. sym-Homospermidine was the major polyamine observed. On the basis of the data reported, it was concluded that UM2(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas histidinilytica sp. nov. is proposed. The type strain is UM2(T) (=MTCC 9473(T) =CCM 7545(T)).

Sphingomonas ginsenosidimutans sp. nov., with ginsenoside converting activity.

The Gram-reaction-negative, strictly aerobic, non-motile, non-spore-forming, and rod-shaped bacterial strain designated Gsoil 1429(T) was isolated from the soil of ginseng cultivating field of Pocheon province in South Korea. This bacterium was characterized in order to determine its taxonomic position by using the polyphasic approach. Strain Gsoil 1429(T) grew well at 25-37°C and at pH 7.0 on R2A and nutrient agar without NaCl supplement. Strain Gsoil 1429(T) had -glucosidase activity, which was responsible for its ability to transform ginsenoside Rb1 (one of the dominant active components of ginseng) to F(2) via gypenoside XVII. On the basis of 16S rRNA gene sequence similarity, strain Gsoil 1429(T) was shown to belong to the family Sphingomonadaceae and to be related to Sphingomonas yunnanensis YIM 003(T) (98.2% sequence similarity), S. phyllosphaerae FA2(T) (97.5%), S. koreensis JSS26(T) (97.3%), and S. asaccharolytica IFO 15499(T) (97.1%). The G+C content of the genomic DNA was 65.6%. The major respiratory quinone was Q-10 and the major fatty acids were summed feature 8 (comprising C(18:1) 7c/ωt/12t), C(16:0) and C(14:0)2OH. DNA and chemotaxonomic data supported the affiliation of strain Gsoil 1429T to the genus Sphingomonas. The DNA-DNA relatedness values between strain Gsoil 1429(T) and its closest phylogenetically neighbours were below 28%. Strain Gsoil 1429(T) could be differentiated genotypically and phenotypically from the recognized species of the genus Sphingomonas. The isolate therefore represents a novel species, for which the name Sphingomonas ginsenosidimutans sp. nov. is proposed, with the type strain Gsoil 1429(T) (=KACC 14949(T) =JCM 17074(T) =LMG 25799(T)).

Efecto de la inoculación de la cepa Sphingomonas paucimobilis 20006FA sobre la composición de un consorcio bacteriano degradador de fenantreno / Effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium

Se estudió el efecto de la inoculación con la cepa Sphingomonas paucimobilis 20006FA sobre la composición bacteriana de un consorcio degradador de fenantreno en cultivos discontinuos (batch) con 8 repiques sucesivos. El consorcio original se obtuvo a partir de un suelo prístino. A los fines del estudio, se obtuvieron y mantuvieron dos consorcios: uno inoculado (F200+I) y otro sin inocular (F200). Se estudió la diversidad bacteriana de los consorcios mediante el análisis de microorganismos cultivables (por caracterización fenotípica y genotípica) y totales (por PCR-DGGE). A lo largo de los repiques sucesivos pudo observarse en ambos consorcios una tendencia a la pérdida de la capacidad degradadora de fenantreno, acompañada por una disminución de la diversidad bacteriana. Si bien la inoculación no produjo cambios significativos en la capacidad degradadora de fenantreno de los consorcios (29,9% para F200 y 27,6% para F200+I hacia el tercer repique), sí produjo cambios en la composición bacteriana, ya que los perfiles de DGGE revelaron una dinámica estructural diferente en el consorcio inoculado. En ambos consorcios se pudo observar la presencia de una banda intensa posicionada a la misma altura que el ADN del inóculo en el gel de DGGE; sin embargo, los cultivos aislados de los consorcios que presentaban idéntica posición de banda en el perfil PCR-DGGE que la cepa S. paucimobilis 20006FA mostraron baja similitud con la cepa inoculada mediante la técnica de RAPD.

The effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium obtained from a pristine soil in sequencing batch cultures was studied. Inoculated (F200+I) and non-inoculated (F200) phenanthrene-degrading consortia, were obtained. Bacterial diversity of consortia was studied at cultivable (phenotype and genotype characterization) and non-cultivable (PCR-DGGE) levels. During the successive cultures, a loss in the phenanthrene-degrading capacity and a decrease in the bacterial diversity were observed in both consortia. Although inoculation did not produce any significant changes in the consortia phenanthrene-degrading capacity (29.9% F200 and 27.6% F200+I), it did produce changes in the bacterial composition, showing a differential structural dynamics in the DGGE profiles of the inoculated consortium. In both consortia, a dominant band placed at the same position as that of the DNA of the inoculant strain in the DGGE gel could be observed. However, isolated cultures from the consortia which had an identical band position to that of S. paucimobilis 20006FA in the PCR-DGGE profile showed low similarity with respect to the inoculant strain (RAPD).

Sphingomonas japonica sp. nov., isolated from the marine crustacean Paralithodes camtschatica.

A Sphingomonas-like bacterium, strain KC7(T), was isolated from a marine crustacean specimen obtained from the Sea of Japan and subjected to a polyphasic study. Comparative 16S rRNA gene sequence analysis positioned the novel strain in the genus Sphingomonas as an independent lineage adjacent to a subclade containing Sphingomonas trueperi LMG 2142(T), Sphingomonas pituitosa EDIV(T) and Sphingomonas azotifigens NBRC 15497(T). Strain KC7(T) shared highest 16S rRNA gene sequence similarity (96.1 %) with S. trueperi LMG 2142(T), Sphingomonas dokdonensis DS-4(T) and S. azotifigens NBRC 15497(T); similarities to strains of other recognized Sphingomonas species were lower (96.0-93.9 %). The strain contained sphingoglycolipid and the predominant fatty acids were C(16 : 1), C(16 : 0) and C(18 : 1); 2-OH C(14 : 0) was the major 2-hydroxy fatty acid. Previously, these lipids have been found to be characteristic of members of the genus Sphingomonas sensu stricto. On the basis of phylogenetic analysis and physiological and biochemical characterization, strain KC7(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas japonica sp. nov. is proposed. The type strain is KC7(T) (=KMM 3038(T) =NRIC 0738(T) =JCM 15438(T)).

Sphingomonas yunnanensis sp. nov., a novel gram-negative bacterium from a contaminated plate.

A Gram-negative bacterium, YIM 003T, which was isolated from a contaminated plate in the laboratory, was subjected to a polyphasic taxonomic study. The organism had short-rod-shaped, motile cells, formed yellow-pigmented colonies on ISP2 medium and its optimum growth pH was 7.0-7.5. The major respiratory lipoquinone was ubiquinone Q-10. The phosphate-containing lipids detected in strain YIM 003T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and one unidentified phospholipid. The major fatty acids were C(18 : 1)omega7c (59.8 %), C(16 : 0) (9.9 %), ai-C(17 : 0) (5.3 %), i-C(17 : 0) (4.4 %) and C(14 : 0) 2-OH (15.8 %). The G+C content of the genomic DNA was 67.5 mol%. Strain YIM 003T exhibited levels of 16S rRNA gene sequence similarity of 98.2 % to Sphingomonas phyllosphaerae FA2T and 98.0 % to Sphingomonas adhaesiva DSM 7418T but showed less than 97.0 % similarity with respect to other species with validly published names. The DNA-DNA relatedness values of the isolate with S. phyllosphaerae FA2T and S. adhaesiva DSM 7418T were 59 and 26 %, respectively. The phenotypic characteristics and genotypic data indicate that strain YIM 003T should be distinguished from S. phyllosphaerae FA2T and S. adhaesiva DSM 7418T. Therefore, on the basis of the polyphasic taxonomic data presented, a novel species of the genus Sphingomonas, Sphingomonas yunnanensis sp. nov., is proposed, with the type strain YIM 003T (=CCTCC AB 204064T=KCTC 12346T).

Characterization and phylogenetic analysis of a phenanthrene-degrading strain isolated from oil-contaminated soil.

Bacterium strain EVA17 was isolated from an oil-contaminated soil, and identified as Sphingomonas sp. based on analysis of 16S rDNA sequence, cellular fatty acid composition and physiological-chemical tests. The salicylate hydroxylase and catechol 2, 3-dioxygenase (C230) were detected in cell-free lysates, suggesting a pathway for phenanthrene catabolism via salicylate and catechol. Alignment showed that both of the C230 and GST genes of the strain EVA17 had high similarity with homologues of strains from genus Sphingomonas. The phylogenetic analysis based on 16S rDNA and C230 gene sequence indicated that EVA17 should be classified into genus Sphingomonas, although the two phylogenetic trees were slightly different from each other. The results of coamplification and sequence determination indicated that GST gene should be located upstream of the C230 gene.

A Sphingomonas bacterium interacting with epithelial cells.

Bacteria of the genus Sphingomonas are environmental organisms that have recently been implicated in a variety of community-acquired and nosocomial infections. During studies on bacteria-cell interactions, we incurred a microorganism contaminating our HeLa cell culture, possibly from water utilized for reagent preparation; this bacterium appeared to tightly adhere to cell monolayers and to survive, with only limited growth rate, which did not seem to alter cells as far as shape, growth rate or survival were concerned. The contaminating organism was isolated and partially characterized by morphological, genetic, and biochemical assays. Mechanisms of cell interaction and entry into epithelial cells were investigated by electron microscopy, immunofluorescence, and biochemical inhibitors. Morphological and biochemical features indicated that the microorganism belonged to the genus Sphingomonas. Electron microscopy showed that contact between the Sphingomonas bacterium and epithelial cells leads to a dramatic alteration of the cell surface, with formation of numerous microvillar extensions plus membrane ruffling. Confocal microscopy and the use of inhibitors showed that actin microfilaments were involved during attachment and entry into HeLa cells. Macropinosome formation and an inhibitory effect by amiloride indicate that internalization occurs in part via a macropinocytosis mechanism. Moreover, cholesterol distribution at the site of bacterial binding suggests that Sphingomonas bacteria could use the lipid rafts as initial binding sites.

Sphingomonas pituitosa sp. nov., an exopolysaccharide-producing bacterium that secretes an unusual type of sphingan.

Strain EDIVT, an exopolysaccharide-producing bacterium, was subjected to polyphasic characterization. The bacterium produced copious amounts of an extracellular polysaccharide, forming slimy, viscous, intensely yellow-pigmented colonies on Czapek-Dox (CZD) agar. The culture fluids of the liquid version of CZD medium were highly viscous after cultivation for 5 d. Cells of strain EDIVT were Gram-negative, catalase-positive, oxidase-negative, nonspore-forming, rod-shaped and motile. Comparisons of 16S rDNA gene sequences demonstrated that EDIVT clusters phylogenetically with the species of the genus Sphingomonas sensu stricto. The G+C content of the DNA (64.5 mol%), the presence of ubiquinone Q-10, the presence of 2-hydroxymyristic acid (14:0 2-OH) as the major hydroxylated fatty acid, the absence of 3-hydroxy fatty acids and the detection of sym-homospermidine as the major component in the polyamine pattern, together with the presence of sphingoglycolipid, supported this delineation. 16S rDNA sequence analysis indicated that strain EDIVT is most closely related (99.4% similarity) to Sphingomonas trueperi LMG 2142T. DNA-DNA hybridization showed that the level of relatedness to S. trueperi is only 45.5%. Further differences were apparent in the cellular fatty acid profile, the polar lipid pattern, the Fourier-transform infrared spectrum and whole-cell proteins and in a number of biochemical characteristics. On the basis of the estimated phylogenetic position derived from 16S rDNA sequence data, DNA-DNA reassociation and phenotypic differences, strain EDIVT (= CIP 106154T = DSM 13101T) was recognized as a new species of Sphingomonas, for which the name Sphingomonas pituitosa sp. nov. is proposed. A component analysis of the exopolysaccharide (named PS-EDIV) suggested that it represents a novel type of sphingan composed of glucose, rhamnose and an unidentified sugar. Glucuronic acid, which is commonly found in sphingans, was absent. The mean molecular mass of PS-EDIV was approximately 3 x 10(6) Da.