SEARCH · PubMed Health

Results for “PSEUDOMONAS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources

PubMed1980

The use of plasmid R1162 and derivatives for gene cloning in the methanol-utilizing Pseudomonas AM1.

A physical map for plasmid R1162 (Sm, Su, IncP4) was constructed. Neither EcoRI, PstI nor EcaI cut within a region essential for replication, molbilization or streptomycin resistence. Plasmid R1162 can replicate in E. coli as well as in Pseudomonas species and shows a strong dependence for DNA polymerase I in E. coli. By RP4 induced mobilization, R1162 can be transferred from E. coli to Pseudomonas AM1. A hybrid plasmid pFG7 (MW=8.4 x 10(6), Sm, Su, Ap, Tc) was constructed between pBR322 and R1162, which allows the selection of hybrid plasmids by insertional inactivation with the restriction enzymes HindIII, BamHI, SalI, ClaI. Transformation of E. coli SK1592 with Ecal-cut and ligated R1162-DNA and Pseudomonas AMI-DNA and subsequent mobilization of the hybrid plasmids into Pseudomonas AM1/M15a (methanol dehydrogenase-) led to the isolation of Pseudomonas AM1/M15a colonies, which could grow on methanol again. Back-conjugation into E. coli SK1592, subsequent mobilization studies and plasmid analysis suggests that the gene for Pseudomonas methanol dehydrogenase has been cloned in this vector.

Cloning, Molecular↗

PubMed2001

Development and utilisation of a medium to isolate phenanthrene-degrading Pseudomonas spp.

In this study, we isolated phenanthrene degraders belonging to Pseudomonas spp. by combining the selective force of two previously described media. The two compounds, sodium lauryl sarcosine and trimethoprim, from the Gould S1 medium, were added to minimal agar plates sprayed with phenanthrene. Pseudomonas spp. that could produce clearing zones were isolated in one step from the rhizosphere without first selecting for Pseudomonas spp. and subsequently screening for degraders or vice versa. Enumeration and isolation of Pseudomonas spp. attached to the rhizosphere showed clear differences between two types of soil. Rhizosphere-attached phenanthrene degraders (from Pseudomonas spp.) were isolated from a former coal gasification site, but were absent in an agricultural soil subjected to organic farming. We isolated 23 phenanthrene degraders producing clearing zones from the rhizosphere of barley roots. All of these 23 isolates (of which 16 were fluorescent in UV light) proved to be members of the Pseudomonas RNA homology group I, on the basis of results of the analytical profile index (API) test system and classic taxonomic tests.

Bacteriological Techniques↗

PubMed2005

Genetic characterization of the poly(hydroxyalkanoate) synthases of various Pseudomonas oleovorans strains.

We identified the poly(hydroxyalkanoate) synthase (PHAS) genes of three strains of Pseudomonas oleovorans by using polymerase chain reaction (PCR)-based detection methods. P. oleovorans NRRL B-14682 contains Class I PHA synthase gene (phaC), NRRL B-14683 harbors Class II phaC1 and phaC2 genes, and NRRL B-778 contain both the Class I and II PHA synthase genes. Inverse-PCR and chromosomal walking techniques were employed to obtain the complete sequences of the Class I phaCs of NRRL B-778 (phbC778; 1698 bps) and B-14682 (phbC14682; 1899 bps). BLAST search indicated that these genes are new and had not been previously cloned. The gene product of phbC778 (i.e., PhbC778; 566 amino acid residues) is homologous to the Class I PHA synthases of Pseudomonas sp. HJ-2 and Pseudomonas sp. strain 61-3, and that of phbC14682 (PhbC14682; 632 amino acids) is homologous to PHAS of Delftia acidovorans. The PhbC14682 contains an extra sequence of 33 amino acids in its conserved alpha/beta-hydrolase domain, making it only the second Class I PHA synthase found to contain this cellular proteolytic sequence. Consistent with their Pseudomonas origin, the codon-usage profiles of PhbC778 and PhbC14682 are similar to those of Pseudomonas Class II PHASs. These new Pseudomonas Class I phbC genes provide valuable addition to the gene pool for the construction of novel PHASs through gene shuffling.

Acyltransferases↗

PubMed2026

Pseudomonas gebzensis sp. nov., a Carotenoid-Producing Species Isolated from Solar Panels in Türkiye.

Strain RP23018ST was isolated from the solar panels in Gebze, Türkiye. According to the phylogenetic analysis of 16S rRNA gene sequences, strain RP23018ST was classified as a member of the genus Pseudomonas, being most closely related to Pseudomonas cremoricolorata DSM 17059T (99.3%). Strain RP23018ST was Gram-stain-negative, rod-shaped, aerobic, motile, growing between temperature range of 4–35 °C. The polar lipids of strain RP23018ST consisted of phosphatidylethanolamine, di-phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid, and three unidentified aminolipids. It was determined that the main respiratory quinone of the RP23018ST strain was ubiquinone-9 (Q-9), which is a typical chemotaxonomic characteristic of the genus Pseudomonas. Major fatty acids were C16:0, summed feature 3 (C16:1 ω6c and/or C16:1 ω7c), summed feature 8 (C18:1 ω6c and/or C18:1 ω7c), and C17:0 cyclo. Strain RP23018ST had a genome size of 4,944,510 bp and a G + C ratio of 63.0%. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between RP23018ᵀ and related Pseudomonas species were below 86.4% and 26.7%, respectively, clearly falling below the thresholds for species delineation. Strain RP23018ST produced a deep yellow carotenoid pigment with absorption maxima at 455 and 482 nm. Genome annotation revealed key carotenoid biosynthesis genes (crtX, crtY, crtI, crtZ), and the extracted pigment showed antioxidant activity in DPPH and FRAP assays. Polyphasic characterization, including the determination of overall genome relatedness indices, revealed that strain RP23018ST represents a novel species of the genus Pseudomonas, for which the name Pseudomonas gebzensis sp. nov. is proposed. The type strain is RP23018ST (= LMG 33436T = DSM 117295T).

Turkey↗

PubMed1995

Biochemical properties of cloned lipases from the Pseudomonas family.

Three Pseudomonas lipases, representing three subfamilies, were analysed for pH optima, destabilization by EGTA and surfactants, phospholipase and cholesterolesterase side activities. All the Pseudomonas lipases tested showed alkaline pH optima. The Pseudomonas cepacia and the P. pseudoalcaligenes lipases were totally inhibited by EGTA at pH 9, and the latter was also fully inhibited at pH 7. The lipase from P. mendocina was not inhibited by EGTA at any of the pH values tested. These findings indicate that a calcium binding site exists in some of the Pseudomonas lipases. The P. pseudoalcaligenes, P. cepacia and P. mendocina lipases were inhibited by the anionic surfactant SDS at concentrations between 0.01-0.5 mg/ml. The P. pseudoalcaligenes and P. cepacia lipases were not inhibited by the nonionic surfactant Brij35 in concentration up to 1 mg/ml, whereas the lipase from P. mendocina was inhibited at 0.1 mg/ml. The P. pseudoalcaligenes and P. cepacia lipases were found to possess high cholesterol esterase activity. P. pseudoalcaligenes lipase was further found to have high phospholipase activity. Ten Pseudomonas lipase sequences were compared by automatic sequence alignment. On the basis of sequence identity we have classified Pseudomonas lipases into five subfamilies.

Amino Acid Sequence↗

PubMed1989

Evidence for the in vivo degradation of human respiratory mucins during Pseudomonas aeruginosa infection.

The comparison of distribution of glycopeptides of sputa from patients suffering from various chronic hypersecretions has already shown an increased acidity with a decreased proportion of neutral glycopeptides in the respiratory secretions of patients suffering from cystic fibrosis, as compared to those of patients with chronic bronchitis. In order to find out whether this decrease is specific to cystic fibrosis mucins or whether it is due to a degradation of mucus by Pseudomonas aeruginosa, which infects most of the sputa from patients with this disease, mucus glycopeptides from patients with different chronic bronchial disorders, infected by Pseudomonas or not, were prepared and fractionated by ion-exchange chromatography. The neutral fraction, which has never been studied in detail, was gel-filtered, and provided two fractions, one containing true mucin glycopeptides and the other containing a mixture of peptides and glycopeptides with a lower molecular mass. In the Pseudomonas-infected samples, the true mucin glycopeptide fraction was greatly diminished as compared to this same fraction in non-Pseudomonas-infected samples; this was not specific to cystic fibrosis secretions. In contrast, the glycopeptide fraction with a lower molecular mass was greatly increased in all the Pseudomonas-infected samples. Polyacrylamide gel electrophoresis of this second fraction showed unique glycopeptide bands between 40-50 kDa in the Pseudomonas-infected samples, regardless of the origin of the samples. These bands were revealed by an antibody directed against whole cystic fibrosis mucin. Infected chronic bronchitis sputa and cystic fibrosis samples without P. aeruginosa did not show these bands. These studies therefore suggest that there are P. aeruginosa-associated changes in mucins which may result from degradation of mucins.

Amino Acids↗

PubMed2004

Influence of plant species on population dynamics, genotypic diversity and antibiotic production in the rhizosphere by indigenous Pseudomonas spp.

The population dynamics, genotypic diversity and activity of naturally-occurring 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas spp. was investigated for four plant species (wheat, sugar beet, potato, lily) grown in two different soils. All four plant species tested, except lily and in some cases wheat, supported relatively high rhizosphere populations (5 x 10(4) to 1 x 10(6) CFU/g root) of indigenous DAPG-producing Pseudomonas spp. during successive cultivation in both a take-all suppressive and a take-all conducive soil. Although lily supported on average the highest population densities of fluorescent Pseudomonas spp., it was the least supportive of DAPG-producing Pseudomonas spp. of all four plant species. The genotypic diversity of 492 DAPG-producing Pseudomonas isolates, assessed by Denaturing Gradient Gel Electrophoresis (DGGE) analysis of the phlD gene, revealed a total of 7 genotypes. Some of the genotypes were found only in the rhizosphere of a specific plant, whereas the predominant genotypes were found at significantly higher frequencies in the rhizosphere of three plant species (wheat, sugar beet and potato). Statistical analysis of the phlD(+) genotype frequencies showed that the diversity of the phlD(+) isolates from lily was significantly lower than the diversity of phlD(+) isolates found on wheat, sugar beet or potato. Additionally, soil type had a significant effect on both the phlD(+) population density and the phlD(+) genotype frequencies, with the take-all suppressive soil being the most supportive. HPLC analysis further showed that the plant species had a significant effect on DAPG-production by the indigenous phlD(+) population: the wheat and potato rhizospheres supported significantly higher amounts of DAPG produced per cell basis than the rhizospheres of sugar beet and lily. Collectively, the results of this study showed that the host plant species has a significant influence on the dynamics, composition and activity of specific indigenous antagonistic Pseudomonas spp.

Analysis of Variance↗

PubMed1999

Phylogeny, ribosomal RNA gene typing and relative abundance of new Pseudomonas species (sensu stricto) isolated from two pinyon-juniper woodland soils of the arid southwest U.S.

Rhizosphere-inhabiting Pseudomonas species interact with plant roots and may be important for plant performance under stressful environmental conditions. A comparison was conducted of culturable Pseudomonas isolates associated with pinyon rhizosphere and between-tree interspace areas in a hot, dry, volcanic cinder field and an adjacent sandy loam soil, in order to identify Pseudomonas species which may be involved in pinyon pine survival under stressful conditions. From a collection of 800 isolates, eleven isolates exhibiting different colony morphology were selected for 16S ribosomal RNA gene sequencing. Phylogenetic analysis of rDNA sequences from the eleven field isolates, forty-six described Pseudomonas species, and thirty-four previously characterized environmental isolates indicated that the isolates from the cinders and sandy loam soil clustered into three groups. The field isolates were distinct from any of the named species or other environmental isolates. Oligonucleotide primer pairs that differentiated three field isolate groups were designed from the 16S rDNA sequences, and eight hundred Pseudomonas field isolates cultured from pinyon rhizospheres and interspaces in the cinders and sandy loam soils were typed into the three groups using PCR assays. The composition of Pseudomonas populations in four environments was significantly different. The relative abundance of the three rDNA-based groups appeared to be affected by both the soil type and the pinyon rhizosphere.

Culture Media↗

PubMed2001

Pseudomonas brenneri sp. nov., a new species isolated from natural mineral waters.

The vernacular name 'fluorescent Pseudomonas group 97-391' was coined for a group of 11 strains isolated from two French natural mineral waters. All these strains were Gram-negative, rod-shaped and motile by means of a single polar flagellum. They produced fluorescent pigment (pyoverdin) on King B medium, catalase and cytochrome oxidase. They were not able to accumulate poly-beta-hydroxybutyrate. They were capable of respiratory but not fermentative metabolism. DNA-DNA hybridization results and DNA base composition analysis revealed that strains of the 'fluorescent Pseudomonas group 97-391' were members of a new species, for which the name Pseudomonas brenneri sp. nov. (type strain CIP 106646T) is proposed. The levels of DNA-DNA relatedness within this group ranged from 70 to 100% with DeltaTm below 1 degree C. The G+C content of the DNA of the type strain was 58 mol%. DNA relatedness with 72 strains representing well-known or partially characterized species of the genus Pseudomonas (sensu stricto) was below 48%. The complete 16S rRNA sequence of the type strain CIP 106646T was determined and compared with those of the type strains of Pseudomonas species. Finally, a phylogenetic tree was inferred from sequence analysis and demonstrated that the new species fell into the 'Pseudomonas fluorescens intrageneric cluster'. The clinical significance of P. brenneri is unknown.

DNA, Bacterial↗

PubMed1999

Taxonomic study of bacteria isolated from Lebanese spring waters: proposal for Pseudomonas cedrella sp. nov. and P. orientalis sp. nov.

Deoxyribonucleic acid relatedness studies (S1 nuclease method) have shown that 15 strains isolated from three Lebanese spring waters, belonging to the genus Pseudomonas, formed two homogeneous DNA groups, with a within-group DNA relatedness ranging from 70 to 100%. These groups are referred to as Pseudomonas cedrella sp. nov. and Pseudomonas orientalis sp.nov. These strains were previously grouped on the basis of a numerical analysis in phenons Ve, Vd, Vg, and VI. DNA relatedness with 65 strains representing 24 species of the genus Pseudomonas sensu stricto was below 50%. The highest DNA binding value (50%) was found with P. marginalis species. A comparison of the complete 16S rRNA gene sequences of the strains representing the two new deoxyribonucleic acid hybridization groups, i.e., strains CFML 96-198T and CFML 96-170T, and the sequence of other strains of the genus Pseudomonas revealed that these strains (CFML 96-198T and CFML 96-170T) fell within the 'Pseudomonas fluorescens intrageneric cluster'. The G+C contents of the DNA of P. cedrella CIP 105541T and P. orientalis CIP 105540T were 59 and 60 mol%, respectively. The two species can be differentiated from each other by the fact that P. cedrella strains hydrolyze erythritol and D-lyxose. P. cedrella grouped together a total of nine strains from phenotypic groups Ve, Vg, and VI. P. orientalis grouped together six strains from both phenotypic groups Vd and Ve.

Bacterial Typing Techniques↗

PubMed2004

Effect of Pseudomonas-induced chronic lung inflammation on specific cytotoxic T-cell responses to adenoviral vectors in mice.

A mouse model of chronic Pseudomonas-induced bronchopulmonary inflammation that mimics chronic cystic fibrosis (CF) lung disease was employed to determine whether this inflammatory milieu influences immune responses to adenoviral vectors. Pseudomonas-infected and control mice were inoculated intranasally with a second-generation type 2 adenovirus (Ad2) vector (Ad2/betagal-2). After 3 weeks, serum and airway Ad2-specific antibodies and Ad2 vector-directed, cytotoxic T-lymphocyte (CTL) activity in splenocytes were measured. No differences in humoral immunity were observed between Pseudomonas-infected mice and controls. However, there was a two- to three-fold increase in Ad-specific CTL activity in the Pseudomonas-infected mice compared to control mice. MHC class I-dependent antigen presentation by antigen-presenting cells (APC) from lungs of Pseudomonas-infected mice was also significantly increased compared to APC from control mice, suggesting a mechanism that may contribute to increased Ad-specific CD8+ CTL responses. It was concluded that Ad-specific CTL activity is enhanced in the setting of pre-existing chronic Pseudomonas-induced lung inflammation similar to CF lung disease, and that increased antigen presentation via MHC class I in this setting may be one underlying mechanism. These findings underscore the importance of considering the influence of the disease milieu when evaluating modes of gene therapy for such diseases in animal models.

Adenoviridae↗

PubMed1997

Arabinanase A from Pseudomonas fluorescens subsp. cellulosa exhibits both an endo- and an exo- mode of action.

Pseudomonas fluorescens subsp. cellulosa expressed arabinanase activity when grown on media supplemented with arabinan or arabinose. Arabinanase activity was not induced by the inclusion of other plant structural polysaccharides, and was repressed by the addition of glucose. The majority of the Pseudomonas arabinanase activity was extracellular. Screening of a genomic library of P. fluorescens subsp. cellulosa DNA constructed in Lambda ZAPII, for recombinants that hydrolysed Red-dyed arabinan, identified five arabinan-degrading plaques. Each of the phage contained the same Pseudomonas arabinanase gene, designated arbA, which was present as a single copy in the Pseudomonas genome. The nucleotide sequence of arbA revealed an open reading frame of 1041 bp encoding a protein, designated arabinanase A (ArbA), of Mr 39438. The N-terminal sequence of ArbA exhibited features typical of a prokaryotic signal peptide. Analysis of the primary structure of ArbA indicated that, unlike most Pseudomonas plant cell wall hydrolases, it did not contain linker sequences or have a modular structure, but consisted of a single catalytic domain. Sequence comparison between the Pseudomonas arabinanase and proteins in the SWISS-PROT database showed that ArbA exhibits greatest sequence identity with arabinanase A from Aspergillus niger, placing the enzyme in glycosyl hydrolase Family 43. The significance of the differing substrate specificities of enzymes in Family 43 is discussed. ArbA purifed from a recombinant strain of Escherichia coli had an Mr of 34000 and an N-terminal sequence identical to residues 32-51 of the deduced sequence of ArbA, and hydrolysed linear arabinan, carboxymethylarabinan and arabino-oligosaccharides. The enzyme displayed no activity against other plant structural polysaccharides, including branched sugar beet arabinan. ArbA produced almost exclusively arabinotriose from linear arabinan and appeared to hydrolyse arabino-oligosaccharides by successively releasing arabinotriose. ArbA and the Aspergillus arabinanase mediated a decrease in the viscosity of linear arabinan that was associated with a significant release of reducing sugar. We propose that ArbA is an arabinanase that exhibits both an endo- and an exo- mode of action.

Amino Acid Sequence↗

PubMed2002

Specific PCR amplification for the genus Pseudomonas targeting the 3' half of 16S rDNA and the whole 16S-23S rDNA spacer.

A PCR protocol was developed for the selective amplification of a segment of the ribosomal RNA operon in Pseudomonas strains. Two specific conserved sequences suitable for PCR priming were identified in the middle of the 16S rDNA and at the very beginning of the 23S rDNA respectively. As a result, amplified region includes the 3' half of the 16S rDNA with the whole 16S-23S rRNA Internal Transcripted Spacer (ITS1) sequence. The specificity of the primer set was checked on sequence databases and validated on collection strains and on one hundred soil bacterial isolates. Our results showed that both collection, soil-inhabiting Pseudomonas and some Pseudomonas-related Azotobacter DNAs could be amplified. This specific PCR for the detection of Pseudomonas strains was in good agreement with colony hybridisation using a Pseudomonas-specific probe. The targeted segment is relevant for a characterisation at the species (16S rDNA) as well as at the infraspecific (ITS1) levels. This PCR-based approach offers promising potential for the characterisation of environmental Pseudomonas populations.

3' Flanking Region↗

PubMed1992

Effect of external urinary collection system on colonization and urinary tract infections with Pseudomonas and Klebsiella in men with spinal cord injury.

Urinary tract infection of men with spinal cord injuries has been associated with a high incidence of colonization of the patients with gram-negative bacilli. We have examined the factors influencing colonization of 119 patients with Pseudomonas and Klebsiella and studied methods of reducing this colonization. The urethra, perineum, rectum, and drainage bag of all patients were cultured on selective media at two week intervals until discharge. The use of the external urinary collection system (EUCS) was discontinued in a group of patients at night, in an attempt to reduce colonization. Pseudomonas and Klebsiella were isolated from one or more body sites in 65 percent and 69 percent of total culture days. The urethra, perineum, rectum, and drainage bags were reservoirs of Pseudomonas and Klebsiella in men with spinal cord injuries, even in the absence of urinary tract infections. The EUCS proved to be an important factor influencing colonization. Pseudomonas and Klebsiella colonization was higher in patients using the EUCS. Removal of the EUCS at night reduced urethral colonization with Pseudomonas, but did not significantly reduce urethral colonization with Klebsiella. The prevalence of bacteriuria with Pseudomonas and Klebsiella was not significantly influenced by the use of the EUCS.

Colony Count, Microbial↗

PubMed1983

Alternative antibiotics for the treatment of Pseudomonas infections in cystic fibrosis.

We have investigated the effectiveness of seven new beta-lactam antibiotics, azlocillin, piperacillin, ceftazidime, cefsulodin, cefoperazone, latamoxef (moxalactam), and cefotaxime, against acute pulmonary exacerbations caused by Pseudomonas aeruginosa in cystic fibrosis. Three hundred and fifty-five strains of Ps aeruginosa isolated from 310 sputum cultures (190 cystic fibrosis patients) were tested for susceptibility to the drugs by determination of minimal inhibitory concentrations (MIC). The highest activity was shown by ceftazidime (6% resistant strains) followed by cefsulodin and piperacillin (15 and 16% resistant strains); very low activity was found for cefotaxime and latamoxef (moxalactam). Ceftazidime was the most active drug against 32 pseudomonas isolates that were resistant to both carbenicillin and aminoglycosides (78% susceptible). A randomized, double-blind trial of azlocillin, piperacillin, ceftazidime, cefsulodin or cefoperazone was performed in 111 cystic fibrosis patients with predominant and susceptible pseudomonas in their sputum. Results were evaluated by a clinical, radiological and bacteriological scoring system: the best results were obtained with ceftazidime, followed by cefsulodin and piperacillin. However, pseudomonas was eradicated in only 22 (23%) of the cases with the most active drugs and persisted or reappeared in all the cases 1 to 3 months later. Ceftazidime always eradicated Staph. aureus and Haemophilus influenzae associated with pseudomonas. Similar eradication occurred nearly always with cefsulodin but rarely with the other drugs. No serious drug reaction occurred but a later fever and rash with piperacillin, transient diarrhoea with cefoperazone, vomiting with cefsulodin, and very frequent eosinophilia with ceftazidime should be mentioned. These five drugs offer, in varying degree, alternatives to traditional anti pseudomonas antibiotics in cystic fibrosis pulmonary infections, but they should be used only against well-proven resistant strains. Ceftazidime is best and cefotaxime and latamoxef (moxalactam) least useful.

Adolescent↗

PubMed1986

Substrate specificity of endo-beta-galactosidases from Flavobacterium keratolyticus and Escherichia freundii is different from that of Pseudomonas sp.

The substrate specificity of endo-beta-galactosidase of Pseudomonas sp. was found to differ from that of Flavobacterium keratolyticus or Escherichia freundii, based on the following experimental results. The endo-beta-galactosidases from these three bacteria released 6-O-sulfo-GlcNAc beta 1-3Gal as one of the major products from keratan sulfates from different sources. In addition to the sulfated disaccharide, Flavobacterium and Escherichia enzymes produced GlcNAc beta 1-3Gal, which is also an integral repeating unit of keratan sulfate, whereas the Pseudomonas enzyme did not release any non-sulfated disaccharide. Tetrasaccharides were prepared from the teleost skin keratan sulfate by digestion with Pseudomonas enzyme followed by gel filtration on Sephadex G-50 chromatography. A part of the tetrasaccharide fraction was hydrolyzed by Flavobacterium enzyme to produce 6-O-sulfo-GlcNAc beta 1-3Gal and GlcNAc beta 1-3Gal, whereas the fraction was completely resistant to retreatment with the Pseudomonas enzyme. Endo-beta-galactosidases from F. keratolyticus and E. freundii hydrolyzed the internal beta-1,4-galactosyl linkage of various neolacto-type glycosphingolipids to produce glucosylceramides. However, these glycosphingolipids were completely resistant to the Pseudomonas enzyme. These findings clearly show that the sulfation on the N-acetylglucosamine adjacent to galactose in the lactosaminoglycans is essential for expression of the Pseudomonas enzyme, but not for that of the Flavobacterium or Escherichia enzyme.

Chromatography, Thin Layer↗

PubMed2006

Biocontrol of avocado dematophora root rot by antagonistic Pseudomonas fluorescens PCL1606 correlates with the production of 2-hexyl 5-propyl resorcinol.

A collection of 905 bacterial isolates from the rhizospheres of healthy avocado trees was obtained and screened for antagonistic activity against Dematophora necatrix, the cause of avocado Dematophora root rot (also called white root rot). A set of eight strains was selected on the basis of growth inhibitory activity against D. necatrix and several other important soilborne phytopathogenic fungi. After typing of these strains, they were classified as belonging to Pseudomonas chlororaphis, Pseudomonas fluorescens, and Pseudomonas putida. The eight antagonistic Pseudomonas spp. were analyzed for their secretion of hydrogen cyanide, hydrolytic enzymes, and antifungal metabolites. P. chlororaphis strains produced the antibiotic phenazine-1-carboxylic acid and phenazine-1-carboxamide. Upon testing the biocontrol ability of these strains in a newly developed avocado-D. necatrix test system and in a tomato-F oxysporum test system, it became apparent that P. fluorescens PCL1606 exhibited the highest biocontrol ability. The major antifungal activity produced by strain P. fluorescens PCL1606 did not correspond to any of the major classes of antifungal antibiotics produced by Pseudomonas biocontrol strains. This compound was purified and subsequently identified as 2-hexyl 5-propyl resorcinol (HPR). To study the role of HPR in biocontrol activity, two Tn5 mutants of P. fluorescens PCL1606 impaired in antagonistic activity were selected. These mutants were shown to impair HRP production and showed a decrease in biocontrol activity. As far as we know, this is the first report of a Pseudomonas biocontrol strain that produces HPR in which the production of this compound correlates with its biocontrol activity.

Ascomycota↗

PubMed1997

The phylogeny of the genera Chryseomonas, Flavimonas, and Pseudomonas supports synonymy of these three genera.

The 16S rRNA sequences of Chryseomonas luteola, the type species of the genus Chryseomonas, and Flavimonas oryzihabitans, the type species of the genus Flavimonas, were determined. These sequences were compared with the sequences of 27 representative strains of the genus Pseudomonas. C. luteola and F. oryzihabitans were located in the cluster that contains Pseudomonas aeruginosa, the type species of genus Pseudomonas Migula 1894, and the levels of 16S rRNA sequence homology between P. aeruginosa and the other two species were more than 93.9%. All of the strains of the genus Pseudomonas sensu stricto whose sequences have been determined were included in the P. aeruginosa cluster. These results suggested that Chryseomonas, Flavimonas, and Pseudomonas are synonymous, and we concluded that Chryseomonas and Flavimonas are junior subjective synonyms of Pseudomonas.

Base Sequence↗