Pseudoxanthomonas Mexicana Research Articles

Bioremediation of heavy metals by an unexplored bacterium, Pseudoxanthomonas mexicana strain GTZY isolated from aerobic-biofilm wastewater system.

We prompted to characterize a wastewater bacterium, Pseudoxanthomonas mexicana GTZY, that efficiently transforms toxic mercury and arsenic, explores its bioremediation capability, and reveals their relevant gene resistance operons. The isolated strain was characterized by its phylogenetic, biochemical, and phenotypic properties. The strain GTZY potentially removed 84.3% of mercury and their mercury volatilization (Hg(II) to Hg(0)) was confirmed using the X-ray film method, and its respective merA gene was PCR amplified. In addition, strain GTZY efficiently removed arsenate (68.5%) and arsenite (63.2%), and showed resistance up to > 175 and > 55mM, respectively. Their genomic annotations disclosed the linkage of Tn2-transposon and int1 in both ends of mer operon (merAPTR). The co-existence of arsP and arsH proteins in its intrinsic ars operon (arsCPRH) was extremely diverse from its ancestral species. We believe that the mercury resistance-conferring mer operon of P. mexicana GTZY presumably derived horizontally from other species in the reactor, while the arsenic resistance-conferring intrinsic ars operon was highly diversified and evolved from its ancestral species. By considering the potential of the strain GTZY to transform heavy metals, this can be used to recover contaminated sites.

Distinctive Bacteria Consortium of Rhizosphere and Surface Soil from Semi-Organic Potato Cultivation in Magelang, Indonesia

Potato cultivation in the middle land is an alternative solution to avoid pathogens. Although it reduces potato quantity and requires more chemical fertilizers to increase production that potentially damages the environment. Therefore, this study aims to characterize contaminations and indigenous microbes from semi-organic potato cultivation centers in Central Java. Soil samples from the semi-organic potato cultivation center of Kledung, Central, were analyzed for metal contamination using the atomic absorption spectrophotometry method and metagenomic soil bacterial diversity profiles. Specifically targeted genes of distinct regions 16SV3-V5. OTUs were identified using Uparse v7.0.1001, while Beta diversity analysis used UniFrac. All these indices in our samples were calculated with QIIME (Version 1.7.0) and displayed with R software (Version 2.15.3). The results showed that semi-organic cultivations had been polluted with Pb > Cd > Cr > As, and carbamate residue was detected in the rhizosphere and surface soil. Manure and compost application alongside NPK fertilizer increases N input, decreasing surface soil bacteria. The surface soil (with a depth of ≤ 5 cm) has a lower index of species richness, diversity, and relative abundance than the rhizosphere layer (depth > 5 cm). Firmicutes, Proteobacteria, and Actinobacterium dominate soil-level bacteria. In comparison, the rhizosphere soil has a higher bacteria diversity dominated by N-tethering rhizobia from the phylum Proteobacteria. The potato root attracts rhizobacteria consortium that support plant growth. A further study should be conducted to describe how the bacterial consortium formed, rhizobia migration from surface to rhizosphere soil, and its interaction with the potato plants. HIGHLIGHTS Semi-organic potato cultivation in Kledung, Temanggung, Indonesia, is contaminated with heavy metals, especially Pb, which is the highest pollutant, and the carbamate residue Excessive nitrogen (N) input from organic and chemical fertilizers reduces the diversity of soil surface bacteria Then manure application as organic fertilizer introduces pathogenic bacteria such as Eschericia-Shigella, Faecalibaculum, Fusobacteria, Bacilli, and Enterococcus The rhizosphere soil is dominated by N-fixating rhizobia from Proteobacteria, including Pseudoxanthomonas Mexicana, Lysobacteria , Devosia riboflavina, Aminobacter sp., Bosea sp., Allorhizobium, Neorhizobium, Pararhizobium, and Rhizobium GRAPHICAL ABSTRACT

Arsenic-Resistant Plant Growth Promoting Pseudoxanthomonas mexicana S254 and Stenotrophomonas maltophilia S255 Isolated from Agriculture Soil Contaminated by Industrial Effluent

In many areas of developing countries, agriculture soil is irrigated with water from drains contaminated with industrial wastewater that contains many toxic substances including arsenic. Such sites could be explored for arsenic-resistant plant growth-promoting microbes. Ten arsenic-resistant bacteria were isolated from such a site and were characterized. Their ability to resist and reduce/oxidize arsenic was determined. The bacteria were also analyzed for plant growth-promoting abilities such as auxin and hydrogen cyanide production, phosphate solubilization, and nitrogen fixation. The effect of these bacteria on plant growth was determined using Vigna radiata both in presence and absence of arsenic. Bacterial isolates S254 and S255 showed maximum resistance against arsenic; up to 225 mM of As(V) and 25 mM of As(III). The phylogenetic analysis revealed that strain S254 belonged to the species Pseudoxanthomonas mexicana and strain S255 belonged to the species Stenotrophomonas maltophilia. Both P. mexicana S254 and S. maltophilia S255 showed positive results for hydrogen cyanide production, auxin production, and nitrogen fixation. P. mexicana S254 produced auxin at a concentration of 14.15 µg mL−1 and S. maltophilia S255 produced auxin as high as 68.75 µg mL−1. Both the bacteria-enhanced the growth of V. radiata and a statistically significant increase in shoot and root lengths was observed both in the presence and absence of arsenic. The application of such bacteria could be helpful for the growth of plants in arsenic-contaminated lands.

Fates of quaternary ammonium compound resistance genes and the corresponding resistant strain in partial nitrification/anammox system under pressure of hexadecyl trimethyl ammonium chloride

Hexadecyl trimethyl ammonium chloride (ATMAC-C16) is a kind of quaternary ammonium compound (QACs) which is extensively consumed as disinfectants, antimicrobials and surfactants. Here, the partial nitrification/anammox (PN/A) system was exposed to different levels of ATMAC-C16 (0–10 mg/L) and the main objective was to reveal the long-term microbiological responses of PN/A system to ATMAC-C16, importantly, explore the tolerance of PN/A to ATMAC-C16 and the key resistant strain. Nitrogen removal efficiency was influenced by environmental and extreme levels of ATMAC-C16 through mainly affecting the anammox (hzsB) gene. Two types of anammox, Candidatus Jettenia and Candidatus Kuenenia, were enriched under the pressure of ATMAC-C16, which allowed PN/A system to maintain good nitrogen removal performance. ATMAC-C16 might cause the hormesis of entire microbial population in PN/A system, leading to the enhancement of cell viability. ATMAC-C16 decreased the relative abundances of most antibiotics resistance genes (ARGs) but significantly enriched QACs resistance genes (QRGs). The tolerance of PN/A system to ATMAC-C16 might be strengthened by inducing the efflux pumps encoding genes (qacH-01/02). Microbial hosts dynamic and co-selection mechanism among ARGs and QRGs resulted in the opposite trends of qacEdeltal-01/02 and qacH-01/02. Pseudoxanthomonas mexicana was identified as the ATMAC-C16 resistant strain, and its resistance to 10 mg/L ATMAC-C16 might not only obtain by capturing the qacH gene, but also benefit from its own efflux pump system. Therefore, from the perspective of the transmission of resistance genes, especially for QRGs, the spread risk of QRGs and ATMAC-C16 resistant strain in PN/A technique should be taken seriously.

Evidence for Pseudoxanthomonas mexicana as the recent origin of the blaAIM-1 carbapenemase gene

ObjectivesElucidating the recent evolutionary history of clinically important antibiotic resistance genes may inform measures to delay the future emergence of additional resistance genes in clinics. This study investigated the recent origin of blaAIM-1, a metallo-β-lactamase gene found in Pseudomonas aeruginosa, and the possible role of ISCR15 in its mobilisation and transfer into clinical species. MethodsComparative genomics were used to identify the recent origin of blaAIM. Mobilisation attempts were performed under different conditions by cloning ISCR15 and the blaAIM-1-like gene in Escherichia coli. ResultsSeveral blaAIM-1 homologues were identified in the Pseudoxanthomonas genus, with conserved synteny of the locus between species and absence of elements associated with mobility. The closest AIM-1 homologue (97.7% amino acid identity) was found in a Pseudoxanthomonas mexicana (P. mexicana) strain. Cloning the blaAIM-like gene in Escherichia coli resulted in high resistance towards carbapenems. While blaAIM-1 is surrounded by ISCR15 elements in clinical strains, in vitro experiments failed to demonstrate their role as mobilising elements. ConclusionsThis study presents evidence that P. mexicana, an environmental species occasionally associated with infections, is the origin of the B3 metallo-β-lactamase AIM-1. The presence of terIS, a plausible recognition site for ISCR15, in other parts of the P. mexicana genome suggests a more complex and yet not understood mobilisation mechanism.

Class 1 In-Tn5393c array contributed to antibiotic resistance of non-pathogenic Pseudoxanthomonas mexicana isolated from a wastewater bioreactor treating streptomycin

The emergence of antibiotic resistance in retort to environmental pollutants during wastewater treatment still remains elusive. Here, we first to investigate the emergence of antibiotic resistance in an environmental non-pathogenic bacterium, Pseudoxanthomonas mexicana isolated from a lab-scale bioreactor treating wastewater containing streptomycin. The molecular mechanism of antibiotic resistance development was evaluated in its genomic, transcriptional, and proteomic levels. The streptomycin resistant (SR) strain showed strong resistance to streptomycin (MIC > 600 μg/mL) as well to sulfamethoxazole, ampicillin, and kanamycin (≥250 μg/mL). A 13.4 kb class-1-integron array consisting of a new arrangement of gene cassette (IS6100-sul1-aadA2-catB3-aacA1-2-aadB-int1-IS256-int) linked with Tn5393c transposon was identified in the SR strain, which has only been reported in clinical pathogens so far. iTRAQ-LC-MS/MS proteomics revealed 22 up-regulated proteins in the SR strain growing under 100 mg L−1 streptomycin, involving antibiotic resistance, toxin production, stress response, and ribosomal protein synthesis. At the mRNA level, elevated expressions of ARGs (strA, strB, and aadB) and 30S-ribosomal protein genes (rpsA and rpsU) were observed in the SR strain. The results highlighted the genomic plasticity and multifaceted regulatory mechanism employed by P. mexicana in adaptation to high-level streptomycin during biological wastewater treatment.

Worldwide distribution and environmental origin of the Adelaide imipenemase (AIM-1), a potent carbapenemase in Pseudomonas aeruginosa.

Carbapenems are potent broad-spectrum β-lactam antibiotics reserved for the treatment of serious infections caused by multidrug-resistant bacteria such as Pseudomonas aeruginosa . The surge in P. aeruginosa resistant to carbapenems is an urgent threat, as very few treatment options remain. Resistance to carbapenems is predominantly due to the presence of carbapenemase enzymes. The assessment of 147 P . aeruginosa isolates revealed that 32 isolates were carbapenem non-wild-type. These isolates were screened for carbapenem resistance genes using PCR. One isolate from wastewater contained the Adelaide imipenemase gene (bla AIM-1) and was compared phenotypically with a highly carbapenem-resistant clinical isolate containing the bla AIM-1 gene. A further investigation of wastewater samples from various local healthcare and non-healthcare sources as well as river water, using probe-based qPCR, revealed the presence of the bla AIM-1 gene in all the samples analysed. The widespread occurrence of bla AIM-1 throughout Adelaide hinted at the possibility of more generally extensive spread of this gene than originally thought. A blast search revealed the presence of the bla AIM-1 gene in Asia, North America and Europe. To elucidate the identity of the organism(s) carrying the bla AIM-1 gene, shotgun metagenomic sequencing was conducted on three wastewater samples from different locations. Comparison of these nucleotide sequences with a whole-genome sequence of a P. aeruginosa isolate revealed that, unlike the genetic environment and arrangement in P. aeruginosa , the bla AIM-1 gene was not carried as part of any mobile genetic elements. A phylogenetic tree constructed with the deduced amino acid sequences of AIM-1 suggested that the potential origin of the bla AIM-1 gene in P. aeruginosa might be the non-pathogenic environmental organism, Pseudoxanthomonas mexicana .

Biocontrol bacteria strains Y4 and Y8 alleviate tobacco bacterial wilt disease by altering their rhizosphere soil bacteria community

Tobacco (Nicotiana tabacum L.) bacterial wilt caused by Ralstonia solanacearum was widespread in recent years, resulting in a great damage in tobacco production. Biological control is an effective measurement for the bacterial wilt, however, related work has not been researched deeply. By screening the biocontrol microorganisms in Wenshan tobacco growing fields in Yunnan province, we discovered a Bacillus amyloliquefaciens strain Y4 and a Pseudomonas sp. strain Y8 that could significantly suppress the growth of R. solanacearum in the culture. The occurrence of wilt disease by field application of Y4 and/or Y8 was 3–4 folds lower than that of the untreatment at different tobacco growth stages. The microbial composition analysis showed that the relative abundance of the Enterobacteriaceae, Sphingomonadaceae, Caulobacteraceae, Sphingobacteriaceae, Flavobacteriacea, Streptomycetaceae, and Burkholderoaceae were significantly increased in the rhizosphere soils of infected tobacco. Moreover, field application of Y4 or Y8 significantly changed the rhizosphere soil microbiota. The relative abundance of the Lactobacillus was increased, however, that of R. solanacearum, Pseudoxanthomonas mexicana, Sphingomonas koreensis, Variovorax paradoxus, and Bradyrhizobium elkanii were decreased. Our results indicate that biocontrol microorganisms reduce plant disease occurrence by changing their microbiota in rhizosphere soil.

Fate and effects of triclosan in subtropical river biofilms

Triclosan (TCS, 5-chloro-2-(2,4-dichlorophenoxy) phenol) is a broad-spectrum antimicrobial compound. Owing to its wide use, TCS has been frequently detected in river systems, especially in the (sub-)tropics. However, little information on its interaction with river biofilm in the (sub)tropics is currently available. In the present study, subtropical river biofilms were chronically exposed to TCS for 14 d at concentrations of 0.1–100 μg/L in artificial river water, which was followed by a 7 d recovery period. The results show that 100 μg/L TCS inhibited the growth of river biofilms and the no-observed-effect concentration (NOEC) of TCS on river biofilms was 10 μg/L. The affected biofilms did not completely recover within the 7 d of recovery period due to the adsorbed TCS which was not removed together with dissolved TCS. Exposure to TCS caused significant changes in prokaryotic species composition of river biofilms but no significant effects on eukaryotic species composition. In particular, the relative abundance of several TCS-tolerant bacterial species (e.g., Pseudoxanthomonas mexicana, Sphingopyxis alaskensis and Sphingomonas wittichii) in river biofilms increased following exposure to 10 and 100 μg/L TCS. River biofilm efficiently removed TCS from the liquid phase and the pH values of the aquatic system significantly affected the removal efficiency of TCS (from 36% at pH 6.5 to 60% at pH 8.5). No degradation products were detected in the liquid phase after 5 days of exposure, possibly due to strong adsorption of the hydrophobic degradation products to river biofilms and through biodegradation by bacteria utilizing TCS and its degradation products as source of carbon and energy for growth, such as Methyloversalitis universalis and Methylobacterium aquaticum.

Pseudoxanthomonas putridarboris sp. nov. isolated from rotten tree.

A Gram-staining-negative, rod-shaped, motile bacterium, designated WD12T, was isolated from a rotten tree at Chungbuk National University, South Korea. WD12T grew optimally at 30-37 °C and pH 7.0-7.5 and could assimilate arbutin and potassium-5-ketogluconate. The major cellular fatty acid were iso-C16 : 0, C16 : 0, cyclo C17 : 0, iso-C15 : 0, summed features 3 (comprising C16 : 1ω7c/iso-C15 : 0 2-OH) and anteiso-C15 : 0. The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major respiratory quinone was ubiquinone-8 (Q-8). The G+C content of the genomic DNA was 69.1 %. The results of phylogenetic and comparative analysis based on the 16S rRNA gene sequence indicated that WD12T formed a tight phylogenetic lineage with Pseudoxanthomonas mexicana AMX 26BT and Pseudoxanthomonas japonensis 12-3T of the the genus Pseudoxanthomonas in the family Xanthomonadaceae. Sequence similarity to other members of the genus Pseudoxanthomonasranged from 98.6 % (P. mexicana AMX 26BT) to 95.1 % (Pseudoxanthomonas taiwanensis CB-226T). DNA-DNA relatedness between WD12T and eight type strains of species of the genus Pseudoxanthomonasshowing more than 97 % 16S rRNA sequence similarity were 6±0-26±1 %. On the basis of the evidence from this polyphasic study, WD12T represents a novel species of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas putridarboris sp. nov. is proposed. The type strain is WD12T (=KACC 15045T=LMG 25968T).

Identification and characterization of endophytic bacteria isolated from in vitro cultures of peach and pear rootstocks.

Endophytes are microorganisms which live symbiotically with almost all varieties of plant and in turn helping the plant in a number of ways. Instead of satisfactory surface sterilization approaches, repeatedly occurring bacterial growth on in vitro rootstock cultures of peach and pear was identified and isolated as endophytic bacteria in our present study. Five different isolates from peach rootstocks were molecularly identified by 16S rRNA gene sequencing as Brevundimonas diminuta, Leifsonia shinshuensis, Sphingomonas parapaucimobilis Brevundimonas vesicularis, Agrobacterium tumefaciens while two endophytic isolates of pear were identified as Pseudoxanthomonas mexicana, and Stenotrophomonas rhizophilia. Identified endophytes were also screened for their potential of plant growth promotion according to indoleacetic acid (IAA) production, nitrogen fixation, solubilization of phosphate and production of siderophore. All seven endophytic isolates have shown positive results for IAA, nitrogen fixation and phosphate solubilization tests. However, two out of seven isolates showed positive results for siderophore production. On the basis of these growth promoting competences, isolated endophytes can be presumed to have significant influence on the growth of host plants. Future studies required to determine the antimicrobial susceptibility profile and potential application of these isolates in biological control, microbial biofertilizers and degradative enzyme production.

糖非発酵グラム陰性細菌由来新規ジペプチド産生酵素の構造と機能

The morbidity of periodontal disease is reported to be 50% above in population worldwide. Some Non-Fermenting Gram-Negative Rods (NFGNR), such as Porphyromonas gingivalis, may cause periodontal disease. NFGNR is well known for utilizing peptides or proteins as energy and carbon sources instead of carbohydrates. DPPs(Dipeptidyl aminopeptidase) are peptide degradation enzymes that play a key part in the absorption of peptides. Bacterial DPPs are divided into two families(Clan SC S9, Clan PA S46). Interestingly, DPPs of Clan PA S46 are only found in bacteria. Our crystallographic studies of Pseudoxanthomonas mexicana WO24 DAP BII and P. gingivalis DPP11 revealed the catalytic and substrate recognition mechanisms of the S46 peptidases.

Cellulolytic Bacteria Associated with the Gut of Dendroctonus armandi Larvae (Coleoptera: Curculionidae: Scolytinae)

The object of this study was to investigate the cellulolytic bacterial community in the intestine of the Chinese white pine beetle (Dendroctonus armandi) larvae. A total of 91 cellulolytic bacteria were isolated and assigned to 11 genotypes using amplified ribosomal DNA restriction analysis (ARDRA). Partial 16S rDNA sequence analysis and morphological tests were used to assign the 11 representative isolates. The results showed that the isolates belonged to α-Proteobacteria, γ-Proteobacteria and Firmicutes. Members of γ-Proteobacteria were the most frequently represented species and accounted for 73.6% of all the cellulolytic bacteria. The majority of cellulolytic bacteria in D. armandi larva gut were identified as Serratia and accounted for 49.5%, followed by Pseudomonas, which accounted for 22%. In addition, members of Bacillus, Brevundimonas, Paenibacillus, Pseudoxanthomonas, Methylobacterium and Sphingomonas were found in the D. armandi larva gut. Brevundimonas kwangchunensis, Brevundimonas vesicularis, Methylobacterium populi and Pseudoxanthomonas mexicana were reported to be cellulolytic for the first time in this study. Information generated from the present study might contribute towards understanding the relationship between bark beetle and its gut flora.

Identification of the catalytic triad of family S46 exopeptidases, closely related to clan PA endopeptidases.

The exopeptidases of family S46 are exceptional, as the closest homologs of these enzymes are the endopeptidases of clan PA. The three-dimensional structure of S46 enzymes is unknown and only one of the catalytic residues, the serine, has been identified. The catalytic histidine and aspartate residues are not experimentally identified. Here we present phylogenetic and experimental data that identify all residues of the catalytic triad of S46 peptidase, dipeptidyl aminopeptidase BII (DAP BII) from Pseudoxanthomonas mexicana WO24. Phylogenetic comparison with the protein and S46 peptidases, revealed His-86, Ser-657, and five aspartate residues as possible catalytic residues. Mutation studies identified the catalytic triad of DAP BII as His-86, Asp-224, and Ser-657, while secondary structure analysis predicted an extended alpha-helical domain in between Asp-224 and Ser-657. This domain is unique for family S46 exopeptidases and its absence from the endopeptidases of clan PA might be key to their different hydrolysis activities.

Influence of hydraulic retention time on partial nitrification of continuous-flow aerobic granular-sludge reactor

This study investigated the effects of hydraulic retention time (HRT) at 12 h, 7.2 h and 2.4 h on partial nitrification efficiency of continuous-flow aerobic granular reactors (CFAGRs) with mature aerobic granules (500±20 mg l−1). At HRT 12 h and 7.2 h, the removal efficiency of both ammonia–nitrogen (NH 4+−N) and nitrite accumulation rate were exceeding 90%. At HRT 2.4 h, NH 4+−N removal efficiency was reduced but most of the conversion efficiency to nitrite was only slightly reduced. At HRT<2.4 h, washout of aerobic granules occurred. In all tests conducted herein, the chemical oxygen demand removal efficiencies exceeded 90%. The clone library results noted the presence of ammonia-oxidizing bacteria belonged to β -Proteobacteria subclass, including 94% of Nitrosomonas europaea and 6% of Nitrosomonas sp. The polymerase chain reaction and denaturing gradient gel electrophoresis results suggested that Alpha proteobacterium, Pseudoxanthomonas mexicana strain, Sphaerotilus natans and Uncultured gamma proteobacterium were responsible for the aerobic granular stability and processing performance. The present CFAGR successfully implemented continuous partial nitrification using aerobic granules at low HRT.

Crystallization and preliminary X-ray crystallographic studies of dipeptidyl aminopeptidase BII from Pseudoxanthomonas mexicana WO24.

Dipeptidyl aminopeptidase BII from Pseudoxanthomonas mexicana WO24 (DAP BII) is able to cleave a variety of dipeptides from the amino-terminus of substrate peptides. For crystallographic studies, DAP BII was overproduced in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. X-ray diffraction data to 2.3 Å resolution were collected using an orthorhombic crystal form belonging to space group P2(1)2(1)2(1), with unit-cell parameters a = 76.55, b = 130.86, c = 170.87 Å. Structural analysis by the multi-wavelength anomalous diffraction method is in progress.

Partial nitrification using aerobic granules in continuous-flow reactor: Rapid startup

This study applied a novel strategy to rapid startup of partial nitrification in continuous-flow reactor using aerobic granules. Mature aerobic granules were first cultivated in a sequencing batch reactor at high chemical oxygen demand in 16 days. The strains including the Pseudoxanthomonas mexicana strain were enriched in cultivated granules to enhance their structural stability. Then the cultivated granules were incubated in a continuous-flow reactor with influent chemical oxygen deamnad being stepped decreased from 1,500 ± 100 (0-19 days) to 750 ± 50 (20-30 days), and then to 350 ± 50 mg l(-1) (31-50 days); while in the final stage 350 mg l(-1) bicarbonate was also supplied. Using this strategy the ammonia-oxidizing bacterium, Nitrosomonas europaea, was enriched in the incubated granules to achieve partial nitrification efficiency of 85-90% since 36 days and onwards. The partial nitrification granules were successfully harvested after 52 days, a period much shorter than those reported in literature.

Physiological characteristics and primary identification of a methane-fed bacterium from a natural gasfield in China

A methane-fed bacterium was enriched, isolated and purified from soil of Dagang gasfield, Tianjin, China. It was a Gram-negative coccus. The biochemical characteristics and morphology of the strain were investigated. The total DNA was extracted, and its 16S rDNA was amplified. The GenBank accession number was JN616389. The bacterium has the highest similarity to Pseudoxanthomonas mexicana with almost 100%. The strain showed a good property of methane utilization when methane was added as a sole carbon source.

Pseudoxanthomonas icgebensis sp. nov., isolated from the midgut of Anopheles stephensi field-collected larvae

A Gram-negative, aerobic, golden yellow, rod-shaped bacterium, a strain designated ICGEB-L15(T), was isolated from the larval midgut of Anopheles stephensi captured in District Jhajjar, Haryana, India. The strain ICGEB-L15(T) grows at 30-50°C (optimum 30-37°C), pH 6.5-8.5 (optimum 7.0-8.0) and in the presence of 2% NaCl. The major fatty acids were iso-C(15:0) (22.5% of total fatty acid), anteiso-C(15:0) (16.5%), iso-C(17:1) 9c (10.3%), iso-C(16:0) (7.3%), C(16:0) (6.1%), and iso-C(11:0) (5.3%). The strain showed the highest 16S rRNA gene sequence similarities with the type strains Pseudoxanthomonas daejeonensis KCTC 12207(T) (97.4%), Pseudoxanthomonas kaohsiungensis J36(T) (97.17%), and Pseudoxanthomonas mexicana AMX 26B(T) (97.11%). The DNA relatedness between ICGEB-L15(T) and Pseudoxanthomonas daejeonensis KCTC 12207(T), Pseudoxanthomonas kaohsiungensis J36(T) and Pseudoxanthomonas mexicana AMX 26B(T) was 24.5%, 28.2%, and 33.6%, respectively. The G+C content of genomic DNA was 69.9 mol%. The major isoprenoid quinone of strain ICGEB-L15(T) was Q-8. The strain ICGEB-L15(T) represents a novel species of the genus Pseudoxanthomonas based on physiological, biochemical and phylogenetic properties; therefore, the name Pseudoxanthomonas icgebensis sp. nov. is proposed. The type strain is ICGEB-L15(T) (=KACC 14090(T) =DSM 22536(T)).

Pseudoxanthomonas indica sp. nov., isolated from a hexachlorocyclohexane dumpsite

A bacterial strain, designated P15(T), was isolated from the soil of an open hexachlorocyclohexane dumpsite. Comparative sequence analysis showed that strain P15(T) displayed high 16S rRNA gene sequence similarities (94.4-97.2 %) with members of the genus Pseudoxanthomonas. The isolate was most closely related to Pseudoxanthomonas mexicana AMX 26B(T) (97.2 % 16S rRNA gene sequence similarity) and Pseudoxanthomonas japonensis 12-3(T) (97.2 %). DNA-DNA relatedness studies showed unambiguously that strain P15(T) represented a novel species that was separate from P. mexicana DSM 17121(T) (7.7 %) and P. japonensis DSM 17109(T) (9.4 %). The predominant cellular fatty acids of strain P15(T) were iso-C₁₆:₀ (21.4 %), iso-C₁₅:₀ (16.1 %), summed feature 9 (comprising iso-C₁₇:₁ω9c and/or 10-methyl C₁₆:₀; 14.9 %), iso-C₁₁:₀ 3-OH (8.3 %) and iso-C₁₄:₀ (7.0 %). The polar lipid profile of strain P15(T) showed the presence of large amounts of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol in addition to unknown glycolipids, phospholipids and an amino-group-containing polar lipid. Ubiquinone 8 was found as the major quinone. The polyamine profile showed the presence of spermidine. The DNA G+C content was 62.9±2 mol%. Strain P15(T) is described as representing a new member of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas indica sp. nov. is proposed. The type strain is P15(T) ( = MTCC 8596(T) = CCM 7430(T)).