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Bioscience, Biotechnology, and... Feb 2019Theanine (γ-glutamylethylamide) is an amino acid analog that reduces blood pressure and improves immune responses. The ϒ-glutamyltranspeptidase (GGT) from Pseudomonas...
Theanine (γ-glutamylethylamide) is an amino acid analog that reduces blood pressure and improves immune responses. The ϒ-glutamyltranspeptidase (GGT) from Pseudomonas nitroreducens IFO12694 (PnGGT) has a unique preference for primary amines as ϒ-glutamyl acceptors over standard L-amino acids and peptides. This characteristic is useful for the synthesis of theanine. We used X-ray crystallographic analysis to understand the structural basis of PnGGT's hydrolysis and transpeptidation reactions and to characterize its previously unidentified acceptor site. Structural studies of PnGGT have shown that key interactions between three residues (Trp385, Phe417, and Trp525) distinguish PnGGT from other GGTs. We studied the roles of these residues in the distinct biochemical properties of PnGGT using site-directed mutagenesis. All mutants showed a significant decrease in hydrolysis activity and an increase in transpeptidase activity, suggesting that the aromatic side chains of Trp385, Phe417, and Trp525 were involved in the recognition of acceptor substrates. Abbreviations: ϒ-glutamyl peptide, theanine, X-ray crystallography.
Topics: Amino Acid Sequence; Amino Acids; Bacterial Proteins; Catalytic Domain; Crystallography, X-Ray; Hydrolysis; Mutagenesis, Site-Directed; Protein Conformation; Pseudomonas; Sequence Homology, Amino Acid; Substrate Specificity; gamma-Glutamyltransferase
PubMed: 30507352
DOI: 10.1080/09168451.2018.1547104 -
Current Microbiology Dec 2022Polyethylene terephthalate (PET) as one of the main crude oil-based derivatives, produces a significant amount of waste that is difficult to degrade. Currently,...
Polyethylene terephthalate (PET) as one of the main crude oil-based derivatives, produces a significant amount of waste that is difficult to degrade. Currently, microbial degradation of PET is an eco-friendly, efficient, and economical method. This study was conducted to propose a novel screening strategy for PET-degrading bacteria, and evaluate their degradation efficiency of PET. Two strains, Pseudomonas nitroreducens S8 and Pseudomonas monteilii S17, were isolated and could utilize PET as a carbon source by co-culture. The combined use of both bacteria gave a synergistic effect on the disruption of the PET surface through colonization behavior, which could enhance the subsequent degradation of PET. Its time of reaching a peak value of PET degradation rate (94.5% at 6 d) was 2 days earlier than these of single bacteria. A similar synergistic effect was also observed in the metabolization of PET monomers, and the metabolic rate was expressed as 82.4% of bis (2-hydroxyethyl) terephthalate (BHET), 64.0% of mono (2-hydroxyethyl) terephthalate (MHET), and 20.0% of terephthalic acid (TPA), respectively. This study is novel in showing the degradation of PET waste by combinations of bacterial pretreatment and enzymatic treatment, which can be a promising method.
Topics: Petroleum; Pseudomonas
PubMed: 36474116
DOI: 10.1007/s00284-022-03139-2 -
Journal of Hazardous Materials Sep 2023The presence of the sulfonic acid group in sulfonated anthraquinones (SAs) resulted in the difficulty in the mineralization of anthraquinone ring. Little information is...
The presence of the sulfonic acid group in sulfonated anthraquinones (SAs) resulted in the difficulty in the mineralization of anthraquinone ring. Little information is available on the removal pathway of the sulfonic acid group of SAs under aerobic/anaerobic conditions. Herein, sodium 1-aminoanthraquinone-2-sulfonate (ASA-2) was used as an important intermediate of SAs. A novel Pseudomonas nitroreducens WA capable of ASA-2 desulfonation was isolated from the Reactive Blue 19-degrading consortium WRB. Anaerobic desulfonation efficiency of 0.165 mM ASA-2 by strain WA reached 99% in 36 h at pH 7.5 and 35 ℃ using glucose as an electron donor. Further analysis showed that ASA-2 as an electron acceptor could be anaerobically transformed into 1-aminoanthraquinone and sulfite via the cleavage of C-S bond. Strain WA could also desulfonate sodium 1-amino-4-bromoanthraquinone-2-sulfonate and sodium anthraquinone-2-sulfonate. Under denitrification conditions, the formed sulfite could be oxidized to sulfate by nitrite via a chemical reaction, which was beneficial for nitrite removal. This phenomenon was observed in consortium WRB-amended system. Moreover, the consortium WRB could reduce the formed sulfite to sulfide due to the presence of Desulfovibrio. These results provide a theoretical basis for the anaerobic biodesulfonation of SAs along with nitrate removal and support for the development of sulfite-based biotechnology.
Topics: Nitrates; Sulfonic Acids; Nitrites; Anaerobiosis; Anthraquinones; Alkanesulfonates; Biotransformation; Sulfites; Denitrification
PubMed: 37348367
DOI: 10.1016/j.jhazmat.2023.131887 -
Plant Cell Reports Jun 2018Pseudomonas nitroreducens: strain IHB B 13561 (PnIHB) enhances the growth of Arabidopsis thaliana and Lactuca sativa via the stimulation of cell development and nitrate...
Pseudomonas nitroreducens: strain IHB B 13561 (PnIHB) enhances the growth of Arabidopsis thaliana and Lactuca sativa via the stimulation of cell development and nitrate absorption. Plant growth-promoting rhizobacteria (PGPR) enhance plant development through various mechanisms; they improve the uptake of soil resources by plants to greatly promote plant growth. Here, we used Arabidopsis thaliana seedlings and Lactuca sativa to screen the growth enhancement activities of a purified PGPR, Pseudomonas nitroreducens strain IHB B 13561 (PnIHB). When cocultivated with PnIHB, both species of plants exhibited notably improved growth, particularly in regard to biomass. Quantitative reverse transcription polymerase chain reaction analysis indicated high expression levels of the nitrate transporter genes, especially NRT2.1, which plays a major role in the high-affinity nitrate transport system in roots. Moreover, enhanced activity of the cyclin-B1 promoter was observed when wild-type 'Columbia-0' Arabidopsis seedlings were exposed to PnIHB, whereas upregulation of cyclin-B also occurred in the inoculated lettuce seedlings. Overall, these results suggest that PnIHB improves A. thaliana and L. sativa growth via specific pathways involved in the promotion of cell development and enhancement of nitrate uptake.
Topics: Anion Transport Proteins; Arabidopsis; Biomass; Gene Expression Regulation, Plant; Lactuca; Nitrate Transporters; Nitrates; Plant Proteins; Plant Roots; Pseudomonas; Seedlings; Soil; Up-Regulation
PubMed: 29541882
DOI: 10.1007/s00299-018-2275-8 -
Frontiers in Microbiology 2023The root-knot nematodes (RKN), especially spp., are globally emerging harmful animals for many agricultural crops.
INTRODUCTION
The root-knot nematodes (RKN), especially spp., are globally emerging harmful animals for many agricultural crops.
METHODS
To explore microbial agents for biological control of these nematodes, the microbial communities of the rhizosphere soils and roots of sponge gourd () infected and non-infected by nematodes, were investigated using culture-dependent and -independent methods.
RESULTS
Thirty-two culturable bacterial and eight fungal species, along with 10,561 bacterial and 2,427 fungal operational taxonomic units (OTUs), were identified. Nine culturable bacterial species, 955 bacterial and 701 fungal OTUs were shared in both four groups. More culturable bacterial and fungal isolates were detected from the uninfected soils and roots than from the infected soils and roots (except no fungi detected from the uninfected roots), and among all samples, nine bacterial species ( sp., sp., , Enterobacteriaceae sp., , sp., Micrococcaceae sp., Rhizobiaceae sp., and sp.) were shared, with sp. and sp. being dominant. was exclusively present in the infested soils, while , , and sp., together with , sp., , and sp. were found only in the uninfected soils. , sp., , and sp. were only in the uninfected roots while sp. only in infected roots. After infestation, 319 bacterial OTUs (such as ) and 171 fungal OTUs (such as ) were increased in rhizosphere soils, while 181 bacterial OTUs (such as ) and 166 fungal OTUs (such as ) rose their abundance in plant roots. Meanwhile, much more decreased bacterial or fungal OTUs were identified from rhizosphere soils rather than from plant roots, exhibiting the protective effects of host plant on endophytes. Among the detected bacterial isolates, sp. TR27 was discovered to exhibit nematocidal activity, and , sp. P35, and to show repellent potentials for the second stage juveniles, which can be used to develop RKN bio-control agents.
DISCUSSION
These findings provided insights into the interactions among root-knot nematodes, host plants, and microorganisms, which will inspire explorations of novel nematicides.
PubMed: 37303801
DOI: 10.3389/fmicb.2023.1168179 -
Microbiology (Reading, England) Jan 2020Azelaic acid is a dicarboxylic acid that has recently been shown to play a role in plant-bacteria signalling and also occurs naturally in several cereals. Several...
Azelaic acid is a dicarboxylic acid that has recently been shown to play a role in plant-bacteria signalling and also occurs naturally in several cereals. Several bacteria have been reported to be able to utilize azelaic acid as a unique source of carbon and energy, including . In this study, we utilize as a model organism to study bacterial degradation of and response to azelaic acid. We report genetic evidence of azelaic acid degradation and the identification of a transcriptional regulator that responds to azelaic acid in DSM 9128. Three mutants possessing transposons in genes of an acyl-CoA ligase, an acyl-CoA dehydrogenase and an isocitrate lyase display a deficient ability in growing in azelaic acid. Studies on transcriptional regulation of these genes resulted in the identification of an IclR family repressor that we designated as AzeR, which specifically responds to azelaic acid. A bioinformatics survey reveals that AzeR is confined to a few proteobacterial genera that are likely to be able to degrade and utilize azelaic acid as the sole source of carbon and energy.
Topics: Bacteria; Bacterial Proteins; Dicarboxylic Acids; Gene Expression Regulation, Bacterial; Molecular Structure; Mutation; Phylogeny; Promoter Regions, Genetic; Pseudomonas; Repressor Proteins; Transcription Factors
PubMed: 31621557
DOI: 10.1099/mic.0.000865 -
Current Microbiology Feb 2022Production of fuels from renewable resources is of utmost importance due to fast depletion of fossil resources and related environmental issues. The present study...
Production of fuels from renewable resources is of utmost importance due to fast depletion of fossil resources and related environmental issues. The present study explored the intrinsic capability of microbial strains to produce alka(e)nes, the next-generation biofuel, thus to reduce the dependence upon current petroleum fuels. Eight bacterial strains, namely, SDK-1, SDK-2, SDK-6, SDK-7, SDK-8, SDK-9, SDK-10, and SDK-11 were isolated from sludge and soil samples collected from different sources using lauric acid as a substrate with a potential to produce alka(e)nes. Production of different medium- and long-chain alka(e)nes by these isolates was confirmed via gas chromatography-mass spectrometer (GC-MS) analysis. SDK-1 (7.2%), SDK-2 (3.72%), and SDK-6 (3.52%) produced significant proportion of medium-chain hydrocarbons as compared to SDK-10 and control with no production. These isolates may be further investigated for production of these alternative sources of energy. In contrary, maximum fraction of long-chain hydrocarbons is produced in SDK-8 (75.28%) followed by SDK-9 (61.51%). Similarly more than 50% of the total hydrocarbons produced in SDK-8 constitute fossil mimic hydrocarbons while only 10.78% fractions were found in SDK-10. Since these fractions resemble different hydrocarbons obtained from crude oil, hence may be explored for their wide applications in different fields. Biochemical characterization and sequencing of the 16S rRNA gene revealed the homology of SDK-1, SDK-2 and SDK-6 with Pseudomonas aeruginosa, SDK-7 and SDK-9 with Enterobacter cloacae, SDK-8 with Klebsiella pnuemoniae, SDK-10 with Enterobacter hormaechei and SDK-11 with Pseudomonas nitroreducens, respectively.
Topics: Bacteria; Biodegradation, Environmental; Biofuels; Hydrocarbons; Petroleum; RNA, Ribosomal, 16S
PubMed: 35129690
DOI: 10.1007/s00284-022-02781-0 -
ACS Biomaterials Science & Engineering Jan 2020Silver nanocrystals have been successfully fabricated by the bioreduction route using the ethanolic extract of (neem) leaves as the reducing and capping agent without...
Silver nanocrystals have been successfully fabricated by the bioreduction route using the ethanolic extract of (neem) leaves as the reducing and capping agent without solvent interference. The silver nanocrystals were grown in a single-step method, without the influence of external energy or surfactants, and at room temperature. The nanoparticles were prepared from different ratios of silver ions to reducing agent molecules and were characterized by UV-vis spectroscopy and transmission electron microscopy (TEM). The nanoparticles were roughly spherical and polydispersed with diameters of less than 40 nm, as determined with high-resolution transmission electron microscopy (HRTEM). Fast Fourier transform (FFT) analysis and X-ray diffraction (XRD) analysis elucidated the crystalline nature of the nanoparticles. The presence of participating functional groups was determined with Fourier transform infrared (FTIR) spectroscopy. The synthesized silver nanoparticles were analyzed as a potential surface-enhanced Raman spectroscopy (SERS) substrate by incorporating rhodamine B as the Raman reporter molecule. The bioreduction process was monitored through SERS fingerprint, which was evaluated by the change in vibrational energies of metal-ligand bonds. It was possible to detect the SERS spectral pattern of the probe molecules on the Ag nanoparticles without the use of any aggregating agent. Thus, the formation of probable intra- and interparticle hot spots was attributed to evaporation-induced aggregation. Furthermore, stirring and precursor salt concentration influenced the kinetics involved in the fabrication process. The thermal stability of the lyophilized nanoparticles prepared from 0.1 M AgNO was evaluated with thermogravimetric analysis (TGA) and had a residual mass of 60% at 600 °C. X-ray photoelectron spectroscopy (XPS) studies were used to validate the compositional and chemical-state information. The biomass-capped silver nanoparticles provided antimicrobial activity by inhibiting the growth of , a biofilm-forming bacterium, and the fungus, (NII 08123).
Topics: Anti-Infective Agents; Aspergillus; Metal Nanoparticles; Plant Extracts; Pseudomonas; Silver
PubMed: 33463216
DOI: 10.1021/acsbiomaterials.9b01257 -
Biodegradation Jun 2018A bacterial strain NSA02, isolated from contaminated soil and identified as Pseudomonas nitroreducens based on partial 16S rDNA gene sequence analysis and BIOLOG...
A bacterial strain NSA02, isolated from contaminated soil and identified as Pseudomonas nitroreducens based on partial 16S rDNA gene sequence analysis and BIOLOG microbiology analysis, was used to study biodegradation of nicosulfuron in the culture medium. The optimal degradation conditions were determined to be 30 °C and pH 7.0. Batch tests were performed for seven different initial substrate concentrations to observe substrate degradation and associated cell growth. The biodegradation kinetics was found to follow a first-order model with regression values greater than 0.98. Specific degradation rate and specific growth rate of bacterial cells were observed to follow substrate inhibition kinetics, and the maximum values of both rates were observed at 100 mg L of nicosulfuron concentration. Kinetic parameters of three substrate inhibition models (Haldane, Aiba-Edwards and Teissier-Edwards) were fitted to the relationship between those rates and substrate concentrations. With the date obtained, Haldane and Teissier-Edwards models provide better representation when compared to Aiba-Edwards model. Inoculating nicosulfuron-treated soil samples with strain NSA02 resulted in a 5-6 times higher rate of nicosulfuron removal than that in non-inoculated soil. Five metabolites of nicosulfuron degradation were detected and identified by liquid chromatography mass spectrometry, and three possible biotransformation pathways were proposed. These results highlight the potential of the isolated bacterium to be used in the bioremediation of nicosulfuron-contaminated soils.
Topics: Biodegradation, Environmental; Biotransformation; DNA, Ribosomal; Hydrogen-Ion Concentration; Kinetics; Metabolome; Phylogeny; Pseudomonas; Pyridines; Soil Microbiology; Sulfonylurea Compounds; Temperature
PubMed: 29637426
DOI: 10.1007/s10532-018-9828-y -
BMJ Case Reports May 2021A man in his 50s with neutropenic fever and multifocal lung opacities was diagnosed with a viral pneumonia. A small number of bacteria grown from bronchoalveolar lavage...
A man in his 50s with neutropenic fever and multifocal lung opacities was diagnosed with a viral pneumonia. A small number of bacteria grown from bronchoalveolar lavage fluid collected during a repeat bronchoscopy were initially identified as by VITEK-2 and mass spectrometry platforms. Whole-genome sequencing, however, subsequently demonstrated that the bacteria were , representing the first known case of cultured from human lungs.
Topics: Bronchoalveolar Lavage Fluid; Humans; Lung; Male; Pneumonia; Pseudomonas; Pseudomonas Infections; Pseudomonas aeruginosa
PubMed: 34031078
DOI: 10.1136/bcr-2020-241327