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International Journal of Molecular... Feb 2022Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters...
Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters by the transesterification of rhamnose with fatty acid vinyl esters, using lipase from as a biocatalyst. The use of this lipase allows excellent catalytic activity in the synthesis of 4--acylrhamnose (99% conversion and full regioselectivity) after 3 h of reaction using tetrahydrofuran (THF) as the reaction media and an excess of vinyl laurate as the acyl donor. The role of reaction conditions, such as temperature, the substrates molar ratio, organic reaction medium and acyl donor chain-length, was studied. Optimum conditions were found using 35 °C, a molar ratio of 1:3 (rhamnose:acyldonor), solvents with a low logP value, and fatty acids with chain lengths from C4 to C18 as acyl donors. In hydrophilic solvents such as THF and acetone, conversions of up to 99-92% were achieved after 3 h of reaction. In a more sustainable solvent such as 2-methyl-THF (2-MeTHF), high conversions were also obtained (86%). Short and medium chain acyl donors (C4-C10) allowed maximum conversions after 3 h, and long chain acyl donors (C12-C18) required longer reactions (5 h) to get 99% conversions. Furthermore, scaled up reactions are feasible without losing catalytic action and regioselectivity. In order to explain enzyme regioselectivity and its ability to accommodate ester chains of different lengths, homology modelling, docking studies and molecular dynamic simulations were performed to explain the behaviour observed.
Topics: Biocatalysis; Enzymes, Immobilized; Esterification; Esters; Fatty Acids; Hydrophobic and Hydrophilic Interactions; Laurates; Lipase; Pseudomonas stutzeri; Rhamnose; Solvents; Vinyl Compounds
PubMed: 35216354
DOI: 10.3390/ijms23042239 -
Synthetic and Systems Biotechnology Dec 2023A1501 is a non-fluorescent denitrifying bacteria that belongs to the gram-negative bacterial group. As a prominent strain in the fields of agriculture and...
A1501 is a non-fluorescent denitrifying bacteria that belongs to the gram-negative bacterial group. As a prominent strain in the fields of agriculture and bioengineering, there is still a lack of comprehensive understanding regarding its metabolic capabilities, specifically in terms of central metabolism and substrate utilization. Therefore, further exploration and extensive studies are required to gain a detailed insight into these aspects. This study reconstructed a genome-scale metabolic network model for A1501 and conducted extensive curations, including correcting energy generation cycles, respiratory chains, and biomass composition. The final model, iQY1018, was successfully developed, covering more genes and reactions and having higher prediction accuracy compared with the previously published model iPB890. The substrate utilization ability of 71 carbon sources was investigated by BIOLOG experiment and was utilized to validate the model quality. The model prediction accuracy of substrate utilization for A1501 reached 90 %. The model analysis revealed its new ability in central metabolism and predicted that the strain is a suitable chassis for the production of Acetyl CoA-derived products. This work provides an updated, high-quality model of A1501for further research and will further enhance our understanding of the metabolic capabilities.
PubMed: 37927897
DOI: 10.1016/j.synbio.2023.10.001 -
Toxins Nov 2022and the produced aflatoxins cause great hazards to food security and human health across all countries. The control of and aflatoxins in grains during storage is of...
and the produced aflatoxins cause great hazards to food security and human health across all countries. The control of and aflatoxins in grains during storage is of great significance to humans. In the current study, bacteria strain YM6 isolated from sea sediment was demonstrated effective in controlling by the production of anti-fungal volatiles. According to morphological characteristics and phylogenetic analysis, strain YM6 was identified as YM6 can produce abundant volatile compounds which could inhibit mycelial growth and conidial germination of . Moreover, it greatly prevented fungal infection and aflatoxin production on maize and peanuts during storage. The inhibition rate was 100%. Scanning electron microscopy further supported that the volatiles could destroy the cell structure of and prevent conidia germination on the grain surface. Gas chromatography/mass spectrometry revealed that dimethyl trisulfide (DMTS) with a relative abundance of 13% is the most abundant fraction in the volatiles from strain YM6. The minimal inhibitory concentration of DMTS to conidia is 200 µL/L (compound volume/airspace volume). Thus, we concluded that YM6 and the produced DMTS showed great inhibition to , which could be considered as effective biocontrol agents in further application.
Topics: Humans; Aspergillus flavus; Aflatoxins; Pseudomonas stutzeri; Phylogeny
PubMed: 36422962
DOI: 10.3390/toxins14110788 -
Bioresources and Bioprocessing May 2022Prokaryotic Argonaute (pAgo) proteins are well-known oligonucleotide-directed endonucleases, which contain a conserved PIWI domain required for endonuclease activity....
BACKGROUND
Prokaryotic Argonaute (pAgo) proteins are well-known oligonucleotide-directed endonucleases, which contain a conserved PIWI domain required for endonuclease activity. Distantly related to pAgos, PIWI-RE family, which is defined as PIWI with conserved R and E residues, has been suggested to exhibit divergent activities. The distinctive biochemical properties and physiological functions of PIWI-RE family members need to be elucidated to explore their applications in gene editing.
RESULTS
Here, we describe the catalytic performance and cellular functions of a PIWI-RE family protein from Pseudomonas stutzeri (PsPIWI-RE). Structural modelling suggests that the protein possesses a PIWI structure similar to that of pAgo, but with different PAZ-like and N-terminal domains. Unlike previously reported pAgos, recombinant PsPIWI-RE acts as an RNA-guided DNA nuclease, as well as a DNA-guided RNA nuclease. It cleaves single-stranded DNA at temperatures ranging from 20 to 65 °C, with an optimum temperature of 45 °C. Mutation at D525 or D610 significantly reduced its endonuclease activity, confirming that both residues are key for catalysis. Comparing with wild-type, mutant with PIWI-RE knockout is more sensitive to ciprofloxacin as DNA replication inhibitor, suggesting PIWI-RE may potentially be involved in DNA replication.
CONCLUSION
Our study provides the first insights into the programmable nuclease activity and biological function of the unknown PIWI-RE family of proteins, emphasizing their important role in vivo and potential application in genomic DNA modification.
PubMed: 38647609
DOI: 10.1186/s40643-022-00539-x -
PloS One 2020High concentrations of metals in the environment alter bacterial diversity, selecting resistant and tolerant species. The study evaluated the selection of a potential...
High concentrations of metals in the environment alter bacterial diversity, selecting resistant and tolerant species. The study evaluated the selection of a potential bacterial strain from Sepetiba Bay-Rio de Janeiro, Brazil marine sediments to remove Cu and Pb. The bacterial strain isolated from the sediments was used in three different bioassays: (1) Cu at concentrations of 0 (control), 6 and 50 μg.mL-1; (2) Pb at concentrations of 0 (control), 6 and 50 μg.mL-1; (3) Cu + Pb in concentrations of 3 μg.mL-1 Cu + 3 μg.mL-1 Pb (6 μg.mL-1) and 25 μg.mL-1 Cu + 25 μg.mL-1 Pb (50 μg.mL-1). The number of cells and the enzymatic activities of dehydrogenases and esterases were quantified. Results of taxonomic identification indicated the selection of the Pseudomonas stutzeri W228 strain, showing a greater degree of similarity (±73%) with the database used. There was no significant variation in the number of cells, 108 cells.mL-1, which represents a high biomass production in the presence of stressors. However, we observed a reduction in dehydrogenase activity at all tested concentrations of Cu, Pb and Cu + Pb. The activity of esterase increased, indicating a higher energy demand to complete the bacterial life cycle. The study showed significant results for the absorption of Pb by the extracellular polymeric substances (EPS) and the efflux of Cu. The capacity of Pb absorption by EPS can be considered a resistance mechanism, as well as the efflux of Cu, so that the available EPS sites could be occupied by the most toxic ions demonstrating that Pseudomonas stutzeri is resistant to Pb and Cu.
Topics: Bacterial Proteins; Bacteriological Techniques; Biodegradation, Environmental; Biomass; Brazil; Copper; Esterases; Extracellular Polymeric Substance Matrix; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Geologic Sediments; Lead; Oxidoreductases; Pseudomonas stutzeri; Water Pollutants, Chemical
PubMed: 33104697
DOI: 10.1371/journal.pone.0240486 -
International Journal of Nanomedicine 2020Selenium nanoparticles (SeNP) have several applications in the field of biotechnology, including their use as anti-cancer drugs. The purpose of the present study is to...
PURPOSE
Selenium nanoparticles (SeNP) have several applications in the field of biotechnology, including their use as anti-cancer drugs. The purpose of the present study is to analyze the efficacy of green synthesis on the preparation of SeNP and its effect on their anti-cancer properties.
METHODS
A bacterial strain isolated from a freshwater source was shown to efficiently synthesize SeNP with potential therapeutic properties. The quality and stability of the NP were studied by scanning electron microscopy, X-ray diffraction, zeta-potential and FTIR analysis. A cost-effective medium formulation from biowaste having 6% banana peel extract enriched with 0.25 mM tryptophan was used to synthesize the NP. The NP after optimization was used to analyze their anti-tumor and anti-angiogenic activity. For this purpose, first, the cytotoxicity of the NP against cancer cells was analyzed by MTT assay and then chorioallantoic membrane assay was performed to assess anti-angiogenic activity. Further, cell migration assay and clonogenic inhibition assay were performed to test the anti-tumor properties of SeNP. To assess the cytotoxicity of SeNP on healthy RBC, hemolysis assay was performed.
RESULTS
The strain identified as (MH191156) produced phenazine carboxylic acid, which aids the conversion of Se oxyanions to reduced NP state, resulting in particles in the size range of 75 nm to 200 nm with improved stability and quality of SeNP, as observed by zeta (ξ) potential of the particles which was found to be -46.2 mV. Cytotoxicity of the SeNP was observed even at low concentrations such as 5 µg/mL against cervical cancer cell line, ie, HeLa cells. Further, neovascularization was inhibited by upto 30 % in CAMs of eggs coinoculated with SeNp when compared with untreated controls, indicating significant anti-angiogenic activity of SeNP. The NP also inhibited the invasiveness of HeLa cells as observed by decreased cell migration and clonogenic proliferation. These observations indicate significant anti-tumor and anti-angiogenic activity of the SeNP in cervical cancer cells.
CONCLUSION
(MH191156) is an efficient source of Se NP production with potential anti-angiogenic and anti-tumor properties, particularly against cervical cancer cells.
Topics: Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Cell Death; Cell Movement; Cell Proliferation; Cell Survival; Chick Embryo; Costs and Cost Analysis; Female; HeLa Cells; Hemolysis; Humans; Metal Nanoparticles; Phenazines; Pseudomonas stutzeri; Reproducibility of Results; Selenium; Spectroscopy, Fourier Transform Infrared; Static Electricity; Uterine Cervical Neoplasms; X-Ray Diffraction
PubMed: 32606692
DOI: 10.2147/IJN.S247426 -
Journal of Infection and Public Health 2019We report a case of Pseudomonas stutzeri endocarditis in Lebanon. The patient had a recent history of prosthetic aortic valve replacement and presented to the emergency... (Review)
Review
We report a case of Pseudomonas stutzeri endocarditis in Lebanon. The patient had a recent history of prosthetic aortic valve replacement and presented to the emergency department with fever and chills. Transesophageal echocardiography confirmed the presence of a vegetation on the prosthetic valve and blood cultures yielded P. stutzeri. The patient was treated with surgery and antibiotics but deteriorated and passed away four days after admission. To our knowledge, this is the fifth case of P. stutzeri endocarditis reported in the literature, and the first case with early presentation and mortality.
Topics: Aged; Anti-Bacterial Agents; Aortic Valve; Ceftazidime; Chills; Diagnosis, Differential; Echocardiography, Transesophageal; Endocarditis, Bacterial; Heart Valve Prosthesis; Heart Valve Prosthesis Implantation; Humans; Infusions, Intravenous; Male; Postoperative Complications; Prosthesis-Related Infections; Pseudomonas stutzeri
PubMed: 30049610
DOI: 10.1016/j.jiph.2018.07.004 -
Biotechnology Reports (Amsterdam,... Sep 2020Alginate is a group of water-soluble linear polysaccharides comprising of variable units of α-l-guluronic and β-d-mannuronic acid. The alginates are in high demand in...
Alginate is a group of water-soluble linear polysaccharides comprising of variable units of α-l-guluronic and β-d-mannuronic acid. The alginates are in high demand in biomedical, pharmaceutical and bioengineering applications. In the present study, we have isolated a strain of that has potential alginate synthesis. The biochemical and physiochemical characteristic including Carbazole assay, DSC, FTIR and H NMR were confirmed the alginate synthesis efficacy by . Evaluation of alginate for the removal of heavy metals such as Chromium, Cobalt and Lead showed that it effectively adsorbs heavy metals. Further analysis of gelling ability and cytotoxicity evaluation revealed that the alginate can be reconstituted as hydrogel and scaffold. Overall, our findings suggest that the strain may be used to produce alginate at commercial level that has the potential bioremediation and biomedical applications.
PubMed: 32874945
DOI: 10.1016/j.btre.2020.e00517 -
Journal of Bacteriology Sep 2011The compatible solutes ectoine and hydroxyectoine are widely produced by bacteria as protectants against osmotic and temperature stress. l-Aspartate-beta-semialdehyde is...
The compatible solutes ectoine and hydroxyectoine are widely produced by bacteria as protectants against osmotic and temperature stress. l-Aspartate-beta-semialdehyde is used as the precursor molecule for ectoine/hydroxyectoine biosynthesis that is catalyzed by the EctABCD enzymes. l-Aspartate-beta-semialdehyde is a central intermediate in different biosynthetic pathways and is produced from l-aspartate by aspartokinase (Ask) and aspartate-semialdehyde-dehydrogenase (Asd). Ask activity is typically stringently regulated by allosteric control to avoid gratuitous synthesis of aspartylphosphate. Many organisms have evolved multiple forms of aspartokinase, and feedback regulation of these specialized Ask enzymes is often adapted to the cognate biochemical pathways. The ectoine/hydroxyectoine biosynthetic genes (ectABCD) are followed in a considerable number of microorganisms by an askgene (ask_ect), suggesting that Ask_Ect is a specialized enzyme for this osmoadaptive biosynthetic pathway. However, none of these Ask_Ect enzymes have been functionally characterized. Pseudomonas stutzeri A1501 synthesizes both ectoine and hydroxyectoine in response to increased salinity, and it possesses two Ask enzymes: Ask_Lys and Ask_Ect. We purified both Ask enzymes and found significant differences with regard to their allosteric control: Ask_LysC was inhibited by threonine and in a concerted fashion by threonine and lysine, whereas Ask_Ect showed inhibition only by threonine. The ectABCD_askgenes from P. stutzeri A1501 were cloned and functionally expressed in Escherichia coli, and this led to osmostress protection. An E. colistrain carrying the plasmid-based ectABCD_askgene cluster produced significantly more ectoine/hydroxyectoine than a strain expressing the ectABCDgene cluster alone. This finding suggests a specialized role for Ask_Ect in ectoine/hydroxyectoine biosynthesis.
Topics: Amino Acids, Diamino; Aspartate Kinase; Aspartate-Semialdehyde Dehydrogenase; Aspartic Acid; Bacterial Proteins; Computational Biology; DNA, Bacterial; Escherichia coli; Gene Expression Regulation, Bacterial; Lysine; Multigene Family; Plasmids; Pseudomonas stutzeri; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; Stress, Physiological; Threonine; Transcription, Genetic
PubMed: 21725014
DOI: 10.1128/JB.00345-11 -
Journal of Applied Microbiology Feb 2015To investigate the effect of culture conditions and medium components on exopolysaccharide (EPS) production by Pseudomonas stutzeri AS22 and to access the EPS...
AIMS
To investigate the effect of culture conditions and medium components on exopolysaccharide (EPS) production by Pseudomonas stutzeri AS22 and to access the EPS performance as a metal-binding exopolysaccharide.
METHODS AND RESULTS
The EPS production conditions of Ps. stutzeri AS22 in submerged culture were optimized using two approaches for EPS quantification, and its metal-binding capacity was evaluated using both single and mixed metal ions systems. Maximum EPS level was achieved after 24 h of incubation at 30°C with an initial pH of 8.0, 250 rev min(-1) stirring level and 10% inoculum size. 50 g l(-1) starch, 5 g l(-1) yeast extract, 0.5 g l(-1) NaCl, 1.4 g l(-1) K2 HPO4, 0.4 g l(-1) MgSO4, 0.4 g l(-1) CaCl2 and 1 g l(-1) mannose were found to be the most suitable carbon, nitrogen, mineral and additional carbohydrate sources, respectively. From metal-binding experiments, the crude EPS showed interesting metal adsorption capacity adopting the order Pb >> Co > Fe > Cu >> Cd. Lead was preferentially biosorbed with a maximal uptake of 460 mg g(-1) crude EPS.
CONCLUSIONS
Under the optimal culture requirements, EPS level reached 10.2 g l(-1) after 24 h of fermentation, seven times more than the production under initial conditions. According to the metal-binding assay, the crude EPS has potential to be used as a novel biosorbent in the treatment of heavy metals-contaminated water.
SIGNIFICANCE AND IMPACT OF THE STUDY
Our results are interesting in terms of yield as well as efficiency for the potential use of the Ps. stutzeri exopolysaccharide as a metal-absorbent polymer in the bioremediation field.
Topics: Carbon; Fermentation; Metals, Heavy; Nitrogen; Polysaccharides, Bacterial; Pseudomonas stutzeri
PubMed: 25376444
DOI: 10.1111/jam.12688