Conjugal transfer of a TOL-like plasmid and extension of the catabolic potential ofPseudomonas putidaF1

1999 ◽  
Vol 45 (11) ◽  
pp. 898-904 ◽  
Author(s):  
S Hallier-Soulier ◽  
V Ducrocq ◽  
N Truffaut

Strain mX was isolated from a petrol-contaminated soil, after enrichment on minimal medium with 0.5% (v/v) meta-xylene as a sole carbon source. The strain was tentatively characterized as Pseudomonas putida and harboured a large plasmid (pMX) containing xyl genes involved in toluene or meta-xylene degradation pathways via an alkyl monooxygenase and a catechol 2,3-dioxygenase. This new TOL-like plasmid was stable over two hundred generations and was self-transferable. After conjugal transfer to P. putida F1, which possesses the Tod chromosomal toluene biodegradative pathway, the transconjugant P. putida F1(pMX) was able to grow on benzene, toluene, meta-xylene, para-xylene, and ethylbenzene compounds as the sole carbon sources. Catechol 2,3-dioxygenases of the transconjugant cells presented a more relaxed substrate specificity than those of parental cells (strain mX and P. putida F1).Key words: biodegradation, conjugative transfer, toluene, xylene, Pseudomonas.

1991 ◽  
Vol 37 (6) ◽  
pp. 411-418 ◽  
Author(s):  
Mohamed S. Nawaz ◽  
Kirit D. Chapatwala

A bacterium capable of utilizing either acetonitrile as the sole source of carbon and nitrogen or biphenyl as the sole source of carbon was isolated from soil and identified as Pseudomonas aeruginosa. The bacterium also utilized other nitriles, amides, and polychlorinated biphenyls (PCBs) as growth substrates. Acetonitrile- or biphenyl-grown cells oxidized these substrates without a lag. In studies with [14C]acetonitrile, nearly 74% of the carbon was recovered as 14CO2 and 8% was associated with the biomass. In studies with [14C]biphenyl, nearly 68% of the carbon was recovered as 14CO2 and nearly 6% was associated with the biomass. Although higher concentrations of acetonitrile as the sole sources of nitrogen inhibited the rates of [14C]biphenyl mineralization, lower concentrations (0.05%, w/v) gave a 77% stimulation in 14CO2 recovery. Pseudomonas aeruginosa metabolized acetonitrile to ammonia and acetic acid and biphenyl to benzoic acid. The bacterium also simultaneously utilized biphenyl as the sole carbon source and acetonitrile as the sole nitrogen source. However, biphenyl utilization increased only after the depletion of acetronitrile. Metabolites of the mixed substrate were ammonia and benzoic acid, which completely disappeared in the later stages of incubation. Nitrile hydratase and amidase were resposible for the transformation of acetonitrile to acetic acid and ammonia. Key words: biodegradation, acetonitrile, biphenyl, Pseudomonas aeruginosa.


2012 ◽  
Author(s):  
Mohd. Sahaid Hj. Kalil ◽  
Muhammad Zaki ◽  
Wan Mohtar Wan Yusoff ◽  
Mohammad Ramlan Mohd. Salleh

Penyelidikan ini bertujuan untuk menyaring substrat organik bagi untuk penghasilan sel–sel A. woodii teraruh demetilase. Pertumbuhan A. woodii dilakukan dalam medium “Balch” yang mengandungi sumber karbon berbeza dalam keadaan anaerobik. Sebanyak sebelas substrat telah diuji iaitu anisol, 2– dan 3–metoksifenol, asid vanilik, asid siringik, asid 2,3,4–, 2,4,5– dan 3,4,5–trimetoksi benzoik, 2,3,4–, 2,4,5– dan 3,4,5–trimetoksi benzil alkohol. 2–metoksifenol merupakan substrat terbaik untuk pertumbuhan A. woodii pada kadar pertumbuhan spesifik 0.14 j–1. Penghasilan sel–sel teraruh demetilase dilakukan dalam kultur kemostat pada kadar pencairan (D) 0.0j–1. Sel-sel pada keadaan mantap dituai dalam keadaan anaerobik dan dipekatkan sebelum digunakan. Pertumbuhan A. woodii didapati maksimum dengan menggunakan kepekatan 0.62 g/L 2–metoksifenol sebagai sumber karbon tunggal. Tindak balas penyahmetilan oleh sel–sel A. woodii meningkat sebanyak 78% apabila 2–metoksifenol sebanyak 0.31 g/L ditambah dalam medium yang mengandungi fruktosa (1% w/v) semasa kultur kemostat. Kata kunci: tindak balas penyahmetilan; demetilase; sel-sel tertuai; metosiaromatik, Acetobacteriumwoodii The objective of this project was to screen organic substrate suitable for the growth of A. woodii, and as for the production of demethylase. A. woodii was grown in “Balch” medium containing different carbon sources. Eleven substrates were tested including anisole, 2– and 3–methoxyphenol, vanilic acid, syringic acid, 2,3,4–, 2,4,5– and 3,4,5–trimethoxy benzoic acid and 2,3,4–, 2,4,5– and 3,4,5–trimethoxy benzyl alcohol. It was found that 2–methoxyphenol was the best substrate with a specific growth rate of 0.14 h–1. The production of demethylase induced cells was carried out in a chemostat culture at a dilution rate (D) of 0.08 h–1. Cells were harvested at steady state of growth and concentrated before use. Optimal concentration of 2–methoxvphenol as the sole carbon source was 0.62 g/L. Demethylation reaction of 0.31 g/L 2–methoxyphenol by induced culture increases 78% relative to the chemostat culture containing only fructose. Key words: Demethylation reaction; demethylase; harvested cells; methoxyaromatic; Acetobacteriumwoodii


2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Arief Izzairy Zamani ◽  
Susann Barig ◽  
Sarah Ibrahim ◽  
Hirzun Mohd. Yusof ◽  
Julia Ibrahim ◽  
...  

Abstract Background Sugars and triglycerides are common carbon sources for microorganisms. Nonetheless, a systematic comparative interpretation of metabolic changes upon vegetable oil or glucose as sole carbon source is still lacking. Selected fungi that can grow in acidic mineral salt media (MSM) with vegetable oil had been identified recently. Hence, this study aimed to investigate the overall metabolite changes of an omnipotent fungus and to reveal changes at central carbon metabolism corresponding to both carbon sources. Results Targeted and non-targeted metabolomics for both polar and semi-polar metabolites of Phialemonium curvatum AWO2 (DSM 23903) cultivated in MSM with palm oil (MSM-P) or glucose (MSM-G) as carbon sources were obtained. Targeted metabolomics on central carbon metabolism of tricarboxylic acid (TCA) cycle and glyoxylate cycle were analysed using LC–MS/MS-TripleQ and GC–MS, while untargeted metabolite profiling was performed using LC–MS/MS-QTOF followed by multivariate analysis. Targeted metabolomics analysis showed that glyoxylate pathway and TCA cycle were recruited at central carbon metabolism for triglyceride and glucose catabolism, respectively. Significant differences in organic acids concentration of about 4- to 8-fold were observed for citric acid, succinic acid, malic acid, and oxaloacetic acid. Correlation of organic acids concentration and key enzymes involved in the central carbon metabolism was further determined by enzymatic assays. On the other hand, the untargeted profiling revealed seven metabolites undergoing significant changes between MSM-P and MSM-G cultures. Conclusions Overall, this study has provided insights on the understanding on the effect of triglycerides and sugar as carbon source in fungi global metabolic pathway, which might become important for future optimization of carbon flux engineering in fungi to improve organic acids production when vegetable oil is applied as the sole carbon source.


2006 ◽  
Vol 72 (3) ◽  
pp. 1766-1770 ◽  
Author(s):  
Katherine Gammon ◽  
Gareth W. Jones ◽  
Steven J. Hope ◽  
Cláudia M. F. de Oliveira ◽  
Lêda Regis ◽  
...  

ABSTRACT Both Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis produce mosquitocidal toxins during sporulation and are extensively used in the field for control of mosquito populations. All the known toxins of the latter organism are known to be encoded on a large plasmid, pBtoxis. In an attempt to combine the best properties of the two bacteria, an erythromycin resistance-marked pBtoxis plasmid was transferred to B. sphaericus by a mating technique. The resulting transconjugant bacteria were significantly more toxic to Aedes aegypti mosquitoes and were able to overcome resistance to B. sphaericus in a resistant colony of Culex quinquefasciatus, apparently due to the production of Cry11A but not Cry4A or Cry4B. The stability of the plasmid in the B. sphaericus host was moderate during vegetative growth, but segregational instability was observed, which led to substantial rates of plasmid loss during sporulation.


Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3180-3186 ◽  
Author(s):  
Sandeep K. Sharma ◽  
The Su Moe ◽  
Ranjana Srivastava ◽  
Deepak Chandra ◽  
Brahm S. Srivastava

The nonadhesive mutant CD11 of Vibrio cholerae El Tor, defective in expression of mannose-sensitive haemagglutinin, lacks a protein when compared with its parent strain. Determination of the amino acid sequence revealed the identity of the protein as the product of VC1929, which is annotated to encode a protein, DctP, involved in the transport of C4-dicarboxylates. We cloned the dctP gene in pUC19 vector and expressed it in mutant CD11. Expression of DctP in the resulting complemented strain restored virulence, adhesive and colonizing capabilities, mannose-sensitive haemagglutination (MSHA) and ability to grow in medium containing sialic acid as a sole carbon source. The mutation in CD11 was caused by insertion of an adenine nucleotide in the reading frame of dctP. Recombinant purified DctP protein showed MSHA of human red blood cells, and protected rabbits against infection by V. cholerae. The protein was localized in membrane and cell wall fractions. The mutant, recombinant CD11 expressing DctP and parent strains were grown in M9 minimal medium in the presence of various carbohydrates (glucose, malate, fumarate, succinate or N-acetylneuraminic acid). The mutant was unable to grow in minimal medium containing N-acetylneuraminic acid (sialic acid) as the sole carbon source whereas the recombinant and parent strains utilized all the sugars tested. It is concluded that DctP is a mannose-sensitive haemagglutinin and a virulence factor and is involved in the utilization of sialic acid.


1999 ◽  
Vol 181 (18) ◽  
pp. 5600-5605 ◽  
Author(s):  
Jan W. Vrijbloed ◽  
Katja Zerbe-Burkhardt ◽  
Ananda Ratnatilleke ◽  
Andreas Grubelnik-Leiser ◽  
John A. Robinson

ABSTRACT The coenzyme B12-dependent isobutyryl coenzyme A (CoA) mutase (ICM) and methylmalonyl-CoA mutase (MCM) catalyze the isomerization of n-butyryl-CoA to isobutyryl-CoA and of methylmalonyl-CoA to succinyl-CoA, respectively. The influence that both mutases have on the conversion of n- and isobutyryl-CoA to methylmalonyl-CoA and the use of the latter in polyketide biosynthesis have been investigated with the polyether antibiotic (monensin) producer Streptomyces cinnamonensis. Mutants prepared by inserting a hygromycin resistance gene (hygB) into either icmA or mutB, encoding the large subunits of ICM and MCM, respectively, have been characterized. The icmA::hygB mutant was unable to grow on valine or isobutyrate as the sole carbon source but grew normally on butyrate, indicating a key role for ICM in valine and isobutyrate metabolism in minimal medium. ThemutB::hygB mutant was unable to grow on propionate and grew only weakly on butyrate and isobutyrate as sole carbon sources. 13C-labeling experiments show that in both mutants butyrate and acetoacetate may be incorporated into the propionate units in monensin A without cleavage to acetate units. Hence, n-butyryl-CoA may be converted into methylmalonyl-CoA through a carbon skeleton rearrangement for which neither ICM nor MCM alone is essential.


2019 ◽  
Author(s):  
Mitchell G. Thompson ◽  
Luis E. Valencia ◽  
Jacquelyn M. Blake-Hedges ◽  
Pablo Cruz-Morales ◽  
Alexandria E. Velasquez ◽  
...  

ABSTRACTPseudomonas putida is a promising bacterial chassis for metabolic engineering given its ability to metabolize a wide array of carbon sources, especially aromatic compounds derived from lignin. However, this omnivorous metabolism can also be a hindrance when it can naturally metabolize products produced from engineered pathways. Herein we show that P. putida is able to use valerolactam as a sole carbon source, as well as degrade caprolactam. Lactams represent important nylon precursors, and are produced in quantities exceeding one million tons per year[1]. To better understand this metabolism we use a combination of Random Barcode Transposon Sequencing (RB-TnSeq) and shotgun proteomics to identify the oplBA locus as the likely responsible amide hydrolase that initiates valerolactam catabolism. Deletion of the oplBA genes prevented P. putida from growing on valerolactam, prevented the degradation of valerolactam in rich media, and dramatically reduced caprolactam degradation under the same conditions. Deletion of oplBA, as well as pathways that compete for precursors L-lysine or 5-aminovalerate, increased the titer of valerolactam from undetectable after 48 hours of production to ~90 mg/L. This work may serve as a template to rapidly eliminate undesirable metabolism in non-model hosts in future metabolic engineering efforts.


Chemosensors ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Dana DiScenza ◽  
Lauren Intravaia ◽  
Anna Healy ◽  
Sage Dubrawski ◽  
Mindy Levine

Reported herein is the sensitive and selective cyclodextrin-promoted fluorescence detection of benzene, toluene, ethylbenzene, xylene, and cumene (BTEXC) fuel components in contaminated snow samples collected from several locations in the state of Rhode Island. This detection method uses cyclodextrin as a supramolecular scaffold to promote analyte-specific, proximity-induced fluorescence modulation of a high-quantum-yield fluorophore, which leads to unique fluorescence responses for each cyclodextrin-analyte-fluorophore combination investigated and enables unique pattern identifiers for each analyte using linear discriminant analysis (LDA). This detection method operates with high levels of sensitivity (sub-micromolar detection limits), selectivity (100% differentiation between structurally similar compounds, such as ortho-, meta-, and para-xylene isomers), and broad applicability (for different snow samples with varying chemical composition, pH, and electrical conductivity). The high selectivity, sensitivity, and broad applicability of this method indicate significant potential in the development of practical detection devices for aromatic toxicants in complex environments.


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