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Mil-Homens D, Ferreira-Dias S, Fialho AM. Fish oils against Burkholderia and Pseudomonas aeruginosa: in vitro efficacy and their therapeutic and prophylactic effects on infected Galleria mellonella larvae. J Appl Microbiol 2016; 120:1509-19. [PMID: 27012860 DOI: 10.1111/jam.13145] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/17/2016] [Accepted: 03/22/2016] [Indexed: 11/28/2022]
Abstract
AIM This study investigates the antimicrobial effects of fish oil-based formulas rich in omega-3 fatty acids (free fatty acids, ethyl esters or triacylglycerols), against cystic fibrosis (CF) pathogens (Burkholderia cenocepacia K56-2 and Pseudomonas aeruginosa PAO1), often resistant to multiple antibiotics. METHODS AND RESULTS The fish oils have shown antibacterial efficacy, although activity was highest for the one containing the fatty acid EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in their free form (MIC value is 1·87% v/v for both pathogens). To test whether the fish oils could have a therapeutic and prophylactic potential in vivo, we assessed its efficacy using a Galleria mellonella caterpillar model of infection. The treatment of infected larvae with a single dose (7 h post infection) enhances the survival of larvae, being more pronounced with the free fatty acid form (EPAX 6000 FA). Moreover, we observed that the prophylactic food provision of the fish oil EPAX 6000 FA during 12 days prior to bacterial infection extended the life of the infected larvae. CONCLUSION The fish oils, particularly in the free fatty acid form, are active in killing Burkholderia and Ps. aeruginosa. SIGNIFICANCE AND IMPACT OF THE STUDY The possibility of using fish oils for the treatment of bacterial infections in CF patients.
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Affiliation(s)
- D Mil-Homens
- iBB-Institute of Bioengineering and Biosciences, Instituto Superior Técnico, Lisbon, Portugal
| | - S Ferreira-Dias
- LEAF - Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, University of Lisbon, Lisbon, Portugal
| | - A M Fialho
- iBB-Institute of Bioengineering and Biosciences, Instituto Superior Técnico, Lisbon, Portugal.,Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
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Lima D, Viana P, André S, Chelinho S, Costa C, Ribeiro R, Sousa JP, Fialho AM, Viegas CA. Evaluating a bioremediation tool for atrazine contaminated soils in open soil microcosms: the effectiveness of bioaugmentation and biostimulation approaches. Chemosphere 2009; 74:187-192. [PMID: 19004466 DOI: 10.1016/j.chemosphere.2008.09.083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 09/23/2008] [Accepted: 09/24/2008] [Indexed: 05/27/2023]
Abstract
A previously developed potential cleanup tool for atrazine contaminated soils was evaluated in larger open soil microcosms for optimization under more realistic conditions, using a natural crop soil spiked with an atrazine commercial formulation (Atrazerba FL). The doses used were 20x or 200x higher than the recommended dose (RD) for an agricultural application, mimicking over-use or spill situations. Pseudomonas sp. strain ADP was used for bioaugmentation (around 10(7) or 10(8) viable cells g(-1) of soil) and citrate for biostimulation (up to 4.8 mg g(-1) of soil). Bioremediation treatments providing fastest and higher atrazine biodegradation proved to differ according to the initial level of soil contamination. For 20x RD of Atrazerba FL, a unique inoculation with Pseudomonas sp. ADP (9 +/- 1 x 10(7) CFU g(-1)) resulted in rapid atrazine removal (99% of the initial 7.2 +/- 1.6 microg g(-1) after 8d), independent of citrate. For 200x RD, an inoculation with the atrazine-degrading bacteria (8.5 +/- 0.5 x 10(7) CFU g(-1)) supplemented with citrate amendment (2.4 mg g(-1)) resulted in improved biodegradation (87%) compared with bioaugmentation alone (79%), even though 7.8 +/- 2.1 microg of atrazine g(-1) still remained in the soil after 1 wk. However, the same amount of inoculum, distributed over three successive inoculations and combined with citrate, increased Pseudomonas sp. ADP survival and atrazine biodegradation (to 98%, in 1 wk). We suggest that this bioremediation tool may be valuable for efficient removal of atrazine from contaminated field soils thus minimizing atrazine and its chlorinated derivatives from reaching water compartments.
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Affiliation(s)
- D Lima
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av Rovisco Pais, 1049-001 Lisboa, Portugal
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Aragão D, Marques AR, Frazão C, Enguita FJ, Carrondo MA, Fialho AM, Sá-Correia I, Mitchell EP. Cloning, expression, purification, crystallization and preliminary structure determination of glucose-1-phosphate uridylyltransferase (UgpG) from Sphingomonas elodea ATCC 31461 bound to glucose-1-phosphate. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:930-4. [PMID: 16946483 PMCID: PMC2242879 DOI: 10.1107/s1744309106030107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Accepted: 08/01/2006] [Indexed: 05/11/2023]
Abstract
The cloning, expression, purification, crystallization and preliminary crystallographic analysis of glucose-1-phosphate uridylyltransferase (UgpG) from Sphingomonas elodea ATCC 31461 bound to glucose-1-phosphate are reported. Diffraction data sets were obtained from seven crystal forms in five different space groups, with highest resolutions ranging from 4.20 to 2.65 A. The phase problem was solved for a P2(1) crystal form using multiple isomorphous replacement with anomalous scattering from an osmium derivative and a SeMet derivative. The best native crystal in space group P2(1) has unit-cell parameters a = 105.5, b = 85.7, c = 151.8 A, beta = 105.2 degrees . Model building and refinement are currently under way.
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Affiliation(s)
- D. Aragão
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble CEDEX, France
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, P-2781-901 Oeiras, Portugal
| | - A. R. Marques
- Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - C. Frazão
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, P-2781-901 Oeiras, Portugal
| | - F. J. Enguita
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, P-2781-901 Oeiras, Portugal
| | - M. A. Carrondo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, P-2781-901 Oeiras, Portugal
| | - A. M. Fialho
- Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - I. Sá-Correia
- Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
| | - E. P. Mitchell
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble CEDEX, France
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Videira PA, Fialho AM, Marques AR, Coutinho PM, Sá-Correia I. Cloning and sequence analysis of the ces10 gene encoding a Sphingomonas paucimobilis esterase. Appl Microbiol Biotechnol 2003; 61:517-22. [PMID: 12764567 DOI: 10.1007/s00253-003-1226-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2002] [Revised: 12/23/2002] [Accepted: 12/27/2002] [Indexed: 11/25/2022]
Abstract
The ces10 gene of the gellan gum-producing strain Sphingomonas paucimobilis ATCC 31461 was cloned and sequenced. Multi-sequence alignment of the deduced protein indicated that Ces10 belongs to the serine hydrolase family with a potential catalytic triad comprising Ser(153) (within the G-X-S-X-G consensus sequence), His(75) and Asp(125). The mixed block results obtained following pattern search and the low identities detected in a BLAST analysis indicate that Ces10 is significantly different from other characterised bacterial esterases/lipases. Nevertheless, the Ces10 amino acid sequence showed 45% similarity with Rhodococcus sp. heroin esterase and 48% with Bacillus subtilis p-nitrobenzyl esterase. Ces10, with a predicted molecular mass of 30,641 Da, was overproduced in Escherichia coli and purified to homogeneity in a histidine-tagged form. Enzyme assays using p-nitrophenyl-esters (p-NP-esters) with different acyl chain-lengths as the substrate confirmed the anticipated esterase activity. Ces10 exhibited a marked preference for short-chain fatty acids, yielding the highest activity with p-NP-propionate (optimal pH 7.4, optimal temperature 37 degrees C).
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Affiliation(s)
- P A Videira
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
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Marques AR, Ferreira PB, Sá-Correia I, Fialho AM. Characterization of the ugpG gene encoding a UDP-glucose pyrophosphorylase from the gellan gum producer Sphingomonas paucimobilis ATCC 31461. Mol Genet Genomics 2003; 268:816-24. [PMID: 12655408 DOI: 10.1007/s00438-003-0805-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2002] [Accepted: 12/20/2002] [Indexed: 10/25/2022]
Abstract
The ugpGgene, which codes for a UDP-glucose pyrophosphorylase (UGP) (or glucose-1-phosphate uridylyltransferase; EC 2.7.7.9) in Sphingomonas paucimobilis ATCC 31461, was cloned and sequenced. This industrial strain produces the exopolysaccharide gellan, a new commercial gelling agent, and the ugpG gene may convert glucose-1-phosphate into UDP-glucose in the gellan biosynthetic pathway. The ugpG gene is capable of restoring the capacity of an Escherichia coli galU mutant to grow on galactose by functional complementation of its deficiency for UDP-glucose pyrophosphorylase activity. As expected, the predicted gene product shows strong homology to UDP-glucose pyrophosphorylases from several bacterial species. The N-terminal region of UgpG exhibits the motif GXGTRXLPXTK, which is highly conserved among bacterial XDP-sugar pyrophosphorylases, and a lysine residue (K(192)) is located within a VEKP motif predicted to be essential for substrate binding or catalysis. UgpG was purified to homogeneity as a heterologous fusion protein from crude cell extracts prepared from IPTG-induced cells of E. coli, using affinity chromatography. Under denaturing conditions, the fusion protein S-UgpG-His(6) migrated with an estimated molecular mass of 36 kDa [corresponding to the predicted molecular mass of native UgpG (31.2 kDa) plus 5 kDa for the S and histidine tags). Kinetic analysis of UgpG in the reverse reaction (pyrophosphorolysis) showed a typical Michaelis-Menten substrate saturation pattern. The apparent K(m) and V(max) values estimated for UDP-glucose were 7.5 microM and 1275 micromol/min/g.
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Affiliation(s)
- A R Marques
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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Sá-Correia I, Fialho AM, Videira P, Moreira LM, Marques AR, Albano H. Gellan gum biosynthesis in Sphingomonas paucimobilis ATCC 31461: genes, enzymes and exopolysaccharide production engineering. J Ind Microbiol Biotechnol 2002; 29:170-6. [PMID: 12355314 DOI: 10.1038/sj.jim.7000266] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2002] [Accepted: 04/09/2002] [Indexed: 11/08/2022]
Abstract
The commercial gelling agent, gellan, is an extracellular polysaccharide (EPS) produced by Sphingomonas paucimobilis ATCC 31461. In recent years, significant progress in understanding the relationship between gellan structure and properties and elucidation of the biosynthesis and engineering of this recent product of biotechnology has been made. This review focuses on recent advances in this field. Emphasis is given to identification and characterization of genes and enzymes involved, or predicted to be involved, in the gellan biosynthetic pathway, at the level of synthesis of sugar-activated precursors, of the repeat unit assembly and of gellan polymerization and export. Identification of several genes, biochemical characterization of the encoded enzymes and elucidation of crucial steps of the gellan pathway indicate that possibilities now exist for exerting control over gellan production at any of the three levels of its biosynthesis. However, a better knowledge of the poorly understood steps and of the bottlenecks and regulation of the pathway, the characterization of the composition, structure and functional properties of gellan-like polymers produced either by the industrial strain under different culture conditions or by mutants are still required for eventual success of the metabolic engineering of gellan production.
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Affiliation(s)
- I Sá-Correia
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Lisbon 1049-001, Portugal
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Araújo IT, Ferreira MS, Fialho AM, Assis RM, Cruz CM, Rocha M, Leite JP. Rotavirus genotypes P[4]G9, P[6]G9, and P[8]G9 in hospitalized children with acute gastroenteritis in Rio de Janeiro, Brazil. J Clin Microbiol 2001; 39:1999-2001. [PMID: 11326034 PMCID: PMC88069 DOI: 10.1128/jcm.39.5.1999-2001.2001] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fifty-three rotavirus-positive fecal specimens from children with diarrhea admitted to a Rio de Janeiro, Brazil, children's hospital between January 1997 and December 1998 were characterized for P and G types by using reverse transcription-PCR. Genotype P[4]G2 accounted for 21% of isolates, while uncommon genotypes P[8]G9, P[6]G9, and P[4]G9 accounted for 13% of the isolates.
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Affiliation(s)
- I T Araújo
- Departamento de Virologia, Instituto Oswaldo Cruz, Rio de Janeiro, Av. Brazil, 4365, 21045-900, Rio de Janeiro, Brazil
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Tavares IM, Jolly L, Pompeo F, Leitão JH, Fialho AM, Sá-Correia I, Mengin-Lecreulx D. Identification of the Pseudomonas aeruginosa glmM gene, encoding phosphoglucosamine mutase. J Bacteriol 2000; 182:4453-7. [PMID: 10913078 PMCID: PMC94616 DOI: 10.1128/jb.182.16.4453-4457.2000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A search for a potential algC homologue within the Pseudomonas aeruginosa PAO1 genome database has revealed an open reading frame (ORF) of unknown function, ORF540 in contig 54 (July 1999 Pseudomonas genome release), that theoretically coded for a 445-amino-acid-residue polypeptide (I. M. Tavares, J. H. Leitão, A. M. Fialho, and I. Sá-Correia, Res. Microbiol. 150:105-116, 1999). The product of this gene is here identified as the phosphoglucosamine mutase (GlmM) which catalyzes the conversion of glucosamine-6-phosphate to glucosamine-1-phosphate, an essential step in the formation of the cell wall precursor UDP-N-acetylglucosamine. The P. aeruginosa gene has been cloned into expression vectors and shown to restore normal peptidoglycan biosynthesis and cell growth of a glmM Escherichia coli mutant strain. The GlmM enzyme from P. aeruginosa has been overproduced to high levels and purified to homogeneity in a six-histidine-tagged form. Beside its phosphoglucosamine mutase activity, the P. aeruginosa enzyme is shown to exhibit phosphomannomutase and phosphoglucomutase activities, which represent about 20 and 2% of its GlmM activity, respectively.
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Affiliation(s)
- I M Tavares
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
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Videira PA, Cortes LL, Fialho AM, Sá-Correia I. Identification of the pgmG gene, encoding a bifunctional protein with phosphoglucomutase and phosphomannomutase activities, in the gellan gum-producing strain Sphingomonas paucimobilis ATCC 31461. Appl Environ Microbiol 2000; 66:2252-8. [PMID: 10788412 PMCID: PMC101485 DOI: 10.1128/aem.66.5.2252-2258.2000] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pgmG gene of Sphingomonas paucimobilis ATCC 31461, the industrial gellan gum-producing strain, was cloned and sequenced. It encodes a 50,059-Da polypeptide that has phosphoglucomutase (PGM) and phosphomannomutase (PMM) activities and is 37 to 59% identical to other bifunctional proteins with PGM and PMM activities from gram-negative species, including Pseudomonas aeruginosa AlgC. Purified PgmG protein showed a marked preference for glucose-1-phosphate (G1P); the catalytic efficiency was about 50-fold higher for G1P than it was for mannose-1-phosphate (M1P). The estimated apparent K(m) values for G1P and M1P were high, 0.33 and 1.27 mM, respectively. The pgmG gene allowed the recovery of alginate biosynthetic ability in a P. aeruginosa mutant with a defective algC gene. This result indicates that PgmG protein can convert mannose-6-phosphate into M1P in the initial steps of alginate biosynthesis and, together with other results, suggests that PgmG may convert glucose-6-phosphate into G1P in the gellan pathway.
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Affiliation(s)
- P A Videira
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, 1049-001 Lisbon, Portugal
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10
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Tavares IM, Leitão JH, Fialho AM, Sá-Correia I. Pattern of changes in the activity of enzymes of GDP-D-mannuronic acid synthesis and in the level of transcription of algA, algC and algD genes accompanying the loss and emergence of mucoidy in Pseudomonas aeruginosa. Res Microbiol 1999; 150:105-16. [PMID: 10209766 DOI: 10.1016/s0923-2508(99)80028-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The low activity levels of the four GDP-D-mannuronic acid-forming enzymes, even in highly alginate-producing strains of Pseudomonas aeruginosa, have made it difficult to compare enzyme activities accompanying the loss/acquisition of mucoidy. Using optimized conditions, we compared the specific activity of these enzymes in three different mucoid P. aeruginosa cystic fibrosis isolates, in their nonmucoid spontaneous variants, and in mucoid variants that emerged during extended incubation of these nonmucoid forms in acetamide broth. A correlation was established between the promptness of emergence of the mucoid forms and the differing sensitivity to nutrient-limitation-induced death of the nonmucoid compared with the isogenic mucoid population. Consistent with the undetectable levels of algD mRNA in nonmucoid forms and with the concept that the step catalyzed by the algD-encoded GDP-mannose dehydrogenase (GMD) is a key step in control of the alginate pathway, GMD activity was undetectable or showed negligible values in nonmucoid variants and correlated with alginate production. However, phosphomannose isomerase (PMI), phosphomannomutase (PMM), and GDP-mannose pyrophosphorylase (GMP) activities in the nonmucoid forms were only slightly (40-70%) below the values in the mucoid forms. Nevertheless, no transcripts homologous to algA (encoding a bifunctional enzyme that possesses both PMI and GMP activities) were detected in the nonmucoid form, and the levels of algC (encoding PMM) transcripts, although detectable in the nonmucoid variants, were, in general, much higher in the mucoid forms. These apparently intriguing observations were cleared up by the identification of two algA functional homologues in P. aeruginosa, recently reported by others, and by the identification of one algC homologue, in contig225 of the PAO1 genome sequence, defining a polypeptide with a deduced amino acid sequence that showed significant homology with that of enzymes of the phosphohexomutase family found in databases. Results are also consistent with the requirement of PMI, GMP and PMM activities for the supply of GDP-D-mannose to (at least) A-band lipopolysaccharide synthesis, while GMD channels this precursor into the alginate pathway.
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Affiliation(s)
- I M Tavares
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Lisbon, Portugal
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Richau JA, Choquenet D, Fialho AM, Sá-Correia I. Emergence of Cu(++)-tolerant mutants defective in gellan synthesis in Cu(++)-stressed cultures of Sphingomonas paucimobilis. Res Microbiol 1997; 148:251-61. [PMID: 9765805 DOI: 10.1016/s0923-2508(97)85245-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cells defective in gellan synthesis appeared during cultivation of the gellan gum-producing strain Sphingomonas paucimobilis R40 with inhibitory concentrations of copper, supplied as CuCl2. The percentage of less mucoid colonial variants dramatically increased with the increase in Cu++ supplementation, reaching 85% of total viable cells at the maximal concentration for growth. Results reported in this work indicate that emergence of colonial variants defective in gellan synthesis results from Cu(++)-induced mutation and the growth advantage of these mutants in Cu(++)-stressed cultures. In fact, DNA homologous recombination strongly increased with the increase in copper supplementation as indicated by the regeneration of kanamycin-resistant cells of R40 harbouring plasmid pBX404-7, which carries two non-overlapping truncated genes derived from a gene conferring kanamycin resistance. The four major groups of colonial mutants that emerged from Cu(++)-stressed cultures of R40 exhibited reduced growth rate and biomass yield in the absence of Cu++ stress and produced decreased levels of exopolysac-charide (EPS) which yielded solutions of lower or negligible viscosity. The level of increased Cu++ tolerance of these mutants, assessed by the inhibitory effect of Cu++ on growth, correlated with the degree of loss of the ability to secrete high-molecular-mass EPS. Consistent with the growth advantage of gellan-defective mutants in Cu(++)-stressed cultures, the non-producing strain RP10, spontaneously obtained during extended cultivation of R40, also exhibited a higher tolerance to Cu++. In addition, its non-mucoid phenotype was stably maintained during Cu(++)-stressed cultivation despite the stimulation of homologous recombination by Cu++.
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Affiliation(s)
- J A Richau
- Laboratório de Engenharia Bioquímica, Instituto Superior Técnico, Lisboa
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12
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Leitão JH, Fialho AM, Sá-Correia I. Effects of growth temperature on alginate synthesis and enzymes in Pseudomonas aeruginosa variants. J Gen Microbiol 1992; 138:605-10. [PMID: 1317406 DOI: 10.1099/00221287-138-3-605] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Spontaneous variation of the level of alginate synthesis in Pseudomonas aeruginosa was associated with changes in the activity of all four enzymes leading to synthesis of GDP-mannuronic acid, the activated precursor for polymerization. For the high-alginate-producing variant 8821M, alginate yield and properties, as well as the levels of alginate enzymes, were dependent on growth temperature. In contrast, levels of alginate and enzymes in the mucoid parent strain 8821 were very low and near temperature-independent. The difference in the specific activity of GDP-mannose dehydrogenase (GMD), encoded by the algD gene, between the two strains was associated with the alginate biosynthetic ability and with the degree of activation of the algD promoter, measured using the algD-xylE transcription fusion on plasmid pVD2X. Maximal activity of the four enzymes was observed in strain 8821M grown at 30 degrees C, a temperature below the optimum for growth (35 degrees C). The effect of temperature on GMD activity could not be explained by the regulation of the algD promoter by temperature, since expression of pVDZX appeared to be more active at 35 degrees C, when the decrease of pVD2X copy number with increasing temperature was taken into account. The involvement of enzymes that catalyse steps downstream from the formation of the activated precursor should also be considered, as suggested by differences in the molecular mass of alginates synthesized by the two strains at various temperatures. Acetyl content of alginates increased as temperature decreased and strain 8821M produced the highest levels of acetylated polymers. The degree of acetylation appeared to be related to growth rate and could reflect acetyl-CoA availability.
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Affiliation(s)
- J H Leitão
- Laboratório de Engenharia Bioquímica, Instituto Superior Técnico, Lisboa, Portugal
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13
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Fialho AM, Monteiro GA, Sá-Correia I. Conjugal transfer of recombinant plasmids into gellan gum-producing and non-producing variants of Pseudomonas elodea ATCC 31461. Lett Appl Microbiol 1991; 12:85-7. [PMID: 1367002 DOI: 10.1111/j.1472-765x.1991.tb00511.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The conjugal transfer of recombinant plasmids into a gellan gum-producing, rifampicin-resistant strain of Pseudomonas elodea and into one of its non-producing variants, was studied in order to facilitate the cloning of gellan genes. The mobilization frequency of recombinant plasmids derived from pKT240, and of cosmid pJRD215 from Escherichia coli HB101 (hsdM), into the mucoid strain was below the values for the non-mucoid variant and decreased exponentially with plasmid size. Reducing the mating time on solid surfaces led to higher mobilization frequencies. Under optimal conditions, a gene bank (40-50 kb) constructed in the cosmid pJRD215 was efficiently mobilized into Gel- mutants during complementation experiments.
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Affiliation(s)
- A M Fialho
- Laboratório de Engenharia Bioquímica, Instituto Superior Técnico, Lisboa, Portugal
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14
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Leite JP, Monteiro SP, Fialho AM, Pereira HG. A novel avian virus with trisegmented double-stranded RNA and further observations on previously described similar viruses with bisegmented genome. Virus Res 1990; 16:119-26. [PMID: 2385956 DOI: 10.1016/0168-1702(90)90016-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The occurrence in chickens of small viruses with bisegmented double-stranded RNA (dsRNA) genome is confirmed and a new virus with similar properties but with three genome segments is described. Both differ from birnaviruses (Intervirology 25, 141-143, 1986) in having indistinct surface structure, smaller diameters (35 nm), and higher buoyant density (1.4 g/ml) in CsCl but are similar in these respects to viruses previously described in several mammals (Lancet 2, 103-104, 1988; J. Gen. Virol. 69, 2749-2754, 1988; Res. Vet. Sci, in press) under the tentative name of picobirnaviruses (PBV). Genome segment length estimations gave values of 2.6 and 1.9 kbp for the avian PBV and 2.9, 2.4 and 0.9 kbp for the trisegmented viruses. The source and pathogenic potential of these viruses remain to be established.
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Affiliation(s)
- J P Leite
- Department of Virology, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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Fialho AM, Zielinski NA, Fett WF, Chakrabarty AM, Berry A. Distribution of alginate gene sequences in the Pseudomonas rRNA homology group I-Azomonas-Azotobacter lineage of superfamily B procaryotes. Appl Environ Microbiol 1990; 56:436-43. [PMID: 1689562 PMCID: PMC183358 DOI: 10.1128/aem.56.2.436-443.1990] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Chromosomal DNA from group I Pseudomonas species, Azotobacter vinelandii, Azomonas macrocytogens, Xanthomonas campestris, Serpens flexibilis, and three enteric bacteria was screened for sequences homologous to four Pseudomonas aeruginosa alginate (alg) genes (algA, pmm, algD, and algR1). All the group I Pseudomonas species tested (including alginate producers and nonproducers) contained sequences homologous to all the P. aeruginosa alg genes used as probes, with the exception of P. stutzeri, which lacked algD. Azotobacter vinelandii also contained sequences homologous to all the alg gene probes tested, while Azomonas macrocytogenes DNA showed homology to all but algD. X. campestris contained sequences homologous to pmm and algR1 but not to algA or algD. The helical bacterium S. flexibilis showed homology to the algR1 gene, suggesting that an environmentally responsive regulatory gene similar to algR1 exists in S. flexibilis. Escherichia coli showed homology to the algD and algR1 genes, while Salmonella typhimurium and Klebsiella pneumoniae failed to show homology with any of the P. aeruginosa alg genes. Since all the organisms tested are superfamily B procaryotes, these results suggest that within superfamily B, the alginate genes are distributed throughout the Pseudomonas group I-Azotobacter-Azomonas lineage, while only some alg genes have been retained in the Pseudomonas group V (Xanthomonas) and enteric lineages.
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Affiliation(s)
- A M Fialho
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago 60612
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16
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Gatti MS, de Castro AF, Ferraz MM, Fialho AM, Pereira HG. Viruses with bisegmented double-stranded RNA in pig faeces. Res Vet Sci 1989; 47:397-8. [PMID: 2687991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Viruses similar to the bisegmented double-stranded (ds) RNA picobirnaviruses described in human faeces and the intestinal contents of Oryzomys nigripes rats and guinea pigs were isolated from the faeces of pigs taken from several areas in the state of Sao Paulo, Brazil. Samples were collected from 912 pigs of several breeds, aged nine to 61 days, and assayed by polyacrylamide gel electrophoresis with silver staining and a combined enzyme immunoassay for rotavirus and adenovirus, using the simian rotavirus SA11 as control. Electrophoretic profiles resembling the bisegmented dsRNA viruses were detected in 106 pigs with 15.3 per cent occurring in animals with diarrhoea compared to 9.6 per cent in animals without diarrhoea.
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Affiliation(s)
- M S Gatti
- Department of Microbiology and Immunology, Campinas State University, Brazil
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Pereira HG, de Araujo HP, Fialho AM, de Castro L, Monteiro SP. A virus with bi-segmented double-stranded RNA genome in guinea pig intestines. Mem Inst Oswaldo Cruz 1989; 84:137-40. [PMID: 2157131 DOI: 10.1590/s0074-02761989000100025] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- H G Pereira
- Departamento de Virologia, Instituto Oswaldo Cruz, Rio de Janeiro, Brasil
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Abstract
Antibodies reacting with simian rotavirus SA11 were detected by enzyme immunoassay (EIA) and Western blot assay (WBA) in sera from guinea pigs bred for experimental use at the Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. The proportion of antibody-positive animals and the antibody titres rose sharply in 1985, were maintained at a high levels in 1986 and declined in 1987. There were no obvious signs of disease coinciding with serological evidence of infection. Results of WBA suggest that the virus involved belongs to subgroup 1 of group A rotaviruses.
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Affiliation(s)
- L De Castro
- Instituto Oswaldo Cruz, Departamento de Virologia, Rio de Janeiro, Brasil
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Abstract
Preparations of simian rotavirus SA11 maintained in different laboratories were compared with each other by polyacrylamide gel electrophoresis of genomic RNA. Differences in the migration of genome segments 4, 5 and 7 allowed the classification of eight virus preparations into four electrophoretic types.
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Gouvea VS, Alencar AA, Barth OM, de Castro L, Fialho AM, Araújo HP, Majerowicz S, Pereira HG. Diarrhoea in mice infected with a human rotavirus. J Gen Virol 1986; 67 ( Pt 3):577-81. [PMID: 3005482 DOI: 10.1099/0022-1317-67-3-577] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Oral inoculation of newborn mice with the MET strain of human rotavirus produced transient diarrhoeal disease. Light and scanning electron microscopy showed typical rotavirus-induced morphological lesions in the villous epithelium of the small intestine consisting of extensive cytoplasmic vacuolation, villous necrosis and atrophy. Virus recovered from intestinal suspensions of infected mice showed the typical electrophoretic profile of the genome of the inoculated strain. Rotavirus antibody appeared in infected mice 10 to 20 days after inoculation but not in controls or nursing dams. The availability of a small animal model for experimental infection with human rotaviruses should prove useful for virulence and protection studies.
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Abstract
A preparation of simian rotavirus SA11 was shown to contain, in addition to the normal 11 genome segments, an RNA species with electrophoretic mobility slightly higher than that of segment 4. Limiting dilution passages allowed the separation of two virus clones distinguishable from each other by the electrophoretic mobility of that genome segment. Possible implications of this finding in virus behaviour and in the comparison of rotaviruses by RNA electrophoresis are discussed.
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