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Philosophical Transactions of the Royal... Jan 2022Horizontally transferred elements, such as plasmids, can burden host cells with various metabolic and fitness costs and may lead to other potentially detrimental...
Horizontally transferred elements, such as plasmids, can burden host cells with various metabolic and fitness costs and may lead to other potentially detrimental phenotypic effects. Acquisition of the megaplasmid pMPPla107 by various Pseudomonads causes sensitivity to a growth-inhibiting substance that is produced in cultures by Pseudomonads during growth under standard laboratory conditions. After approximately 500 generations of laboratory passage of populations containing pMPPla107, strains from two out of six independent passage lines displayed resistance to this inhibitory agent. Resistance was transferable and is, therefore, associated with mutations occurring on pMPPla107. Resequencing experiments demonstrated that resistance is likely due to a large deletion on the megaplasmid in one line, and to a nonsynonymous change in an uncharacterized megaplasmid locus in the other strain. We further used allele exchange experiments to confirm that resistance is due to this single amino acid change in a previously uncharacterized megaplasmid protein, which we name SkaA. These results provide further evidence that costs and phenotypic changes associated with horizontal gene transfer can be compensated through single mutational events and emphasize the power of experimental evolution and resequencing to better understand the genetic basis of evolved phenotypes. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
Topics: Gene Transfer, Horizontal; Plasmids; Pseudomonas stutzeri; Pseudomonas syringae; Sequence Analysis, DNA
PubMed: 34839711
DOI: 10.1098/rstb.2020.0474 -
Molecules (Basel, Switzerland) Nov 2021Every petroleum-processing plant produces sewage sludge containing several types of polycyclic aromatic hydrocarbons (PAHs). The degradation of PAHs via physical,...
Every petroleum-processing plant produces sewage sludge containing several types of polycyclic aromatic hydrocarbons (PAHs). The degradation of PAHs via physical, biological, and chemical methods is not yet efficient. Among biological methods, the use of marine sponge symbiont bacteria is considered an alternative and promising approach in the degradation of and reduction in PAHs. This study aimed to explore the potential performance of a consortium of sponge symbiont bacteria in degrading anthracene and pyrene. Three bacterial species ( strain GLB197, strain SLG510A3-8, and strain SLCDA 976) were mixed to form the consortium. The interaction between the bacterial consortium suspension and PAH components was measured at 5 day intervals for 25 days. The biodegradation performance of bacteria on PAH samples was determined on the basis of five biodegradation parameters. The analysis results showed a decrease in the concentration of anthracene (21.89%) and pyrene (7.71%), equivalent to a ratio of 3:1, followed by a decrease in the abundance of anthracene (60.30%) and pyrene (27.52%), equivalent to a ratio of 2:1. The level of pyrene degradation was lower than that of the anthracene due to fact that pyrene is more toxic and has a more stable molecular structure, which hinders its metabolism by bacterial cells. The products from the biodegradation of the two PAHs are alcohols, aldehydes, carboxylic acids, and a small proportion of aromatic hydrocarbon components.
Topics: Acinetobacter calcoaceticus; Animals; Anthracenes; Bacillus pumilus; Biodegradation, Environmental; Microbiota; Porifera; Pseudomonas stutzeri; Pyrenes; Symbiosis
PubMed: 34833943
DOI: 10.3390/molecules26226851 -
Brazilian Journal of Otorhinolaryngology 2022
Topics: Humans; Pseudomonas stutzeri; Anti-Bacterial Agents; Olfaction Disorders
PubMed: 34756556
DOI: 10.1016/j.bjorl.2021.08.006 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Oct 2021Biological denitrification is the most widely used technology for nitrate removal in wastewater treatment. Conventional denitrification requires long hydraulic retention...
Biological denitrification is the most widely used technology for nitrate removal in wastewater treatment. Conventional denitrification requires long hydraulic retention time, and the nitrate removal efficiency in winter is low due to the low temperature. Therefore, it is expected to develop new approaches to enhance the denitrification process. In this paper, the effect of adding different concentrations of Fe₃O₄ nanoparticles on the denitrification catalyzed by Pseudomonas stutzeri was investigated. The maximum specific degradation rate of nitrate nitrogen improved from 18.0 h⁻¹ to 23.7 h⁻¹ when the concentration of Fe₃O₄ increased from 0 mg/L to 4 000 mg/L. Total proteins and intracellular iron content also increased along with increasing the concentration of Fe₃O₄. RT-qPCR and label-free proteomics analyses showed that the relative expression level of denitrifying genes napA, narJ, nirB, norR, nosZ of P. stutzeri increased by 55.7%, 24.9%, 24.5%, 36.5%, 120% upon addition of Fe₃O₄, and that of denitrifying reductase Nap, Nar, Nir, Nor, Nos increased by 85.0%, 147%, 16.5%, 47.1%, 95.9%, respectively. No significant difference was observed on the relative expression level of denitrifying genes and denitrifying reductases between the bacteria suspended and the bacteria adhered to Fe₃O₄. Interestingly, the relative expression level of electron transfer proteins of bacteria adhered to Fe₃O₄ was higher than that of the bacteria suspended. The results indicated that Fe₃O₄ promoted cell growth and metabolism through direct contact with bacteria, thereby improving the denitrification. These findings may provide theoretical support for the development of enhanced denitrification.
Topics: Aerobiosis; Denitrification; Nitrates; Nitrogen; Pseudomonas stutzeri
PubMed: 34708620
DOI: 10.13345/j.cjb.210426 -
Microorganisms Oct 2021Bile salts such as cholate are steroid compounds from the digestive tracts of vertebrates, which enter the environment upon excretion, e.g., in manure. Environmental...
Investigations on the Degradation of the Bile Salt Cholate via the 9,10--Pathway Reveals the Formation of a Novel Recalcitrant Steroid Compound by a Side Reaction in sp. Strain Chol11.
Bile salts such as cholate are steroid compounds from the digestive tracts of vertebrates, which enter the environment upon excretion, e.g., in manure. Environmental bacteria degrade bile salts aerobically via two pathway variants involving intermediates with Δ- or Δ-3-keto-structures of the steroid skeleton. Recent studies indicated that degradation of bile salts via Δ-3-keto intermediates in sp. strain Chol11 proceeds via 9,10 cleavage of the steroid skeleton. For further elucidation, the presumptive product of this cleavage, 3,12β-dihydroxy-9,10--androsta-1,3,5(10),6-tetraene-9,17-dione (DHSATD), was provided to strain Chol11 in a co-culture approach with Chol1 and as purified substrate. Strain Chol11 converted DHSATD to the so far unknown compound 4-methyl-3-deoxy-1,9,12-trihydroxyestra-1,3,5(10)7-tetraene-6,17-dione (MDTETD), presumably in a side reaction involving an unusual ring closure. MDTETD was neither degraded by strains Chol1 and Chol11 nor in enrichment cultures. Functional transcriptome profiling of zebrafish embryos after exposure to MDTETD identified a significant overrepresentation of genes linked to hormone responses. In both pathway variants, steroid degradation intermediates transiently accumulate in supernatants of laboratory cultures. Soil slurry experiments indicated that bacteria using both pathway variants were active and also released their respective intermediates into the environment. This instance could enable the formation of recalcitrant steroid metabolites by interspecies cross-feeding in agricultural soils.
PubMed: 34683472
DOI: 10.3390/microorganisms9102146 -
International Journal of Molecular... Oct 2021Many organisms reductively assimilate selenite to synthesize selenoprotein. Although the thioredoxin system, consisting of thioredoxin 1 (TrxA) and thioredoxin reductase...
Many organisms reductively assimilate selenite to synthesize selenoprotein. Although the thioredoxin system, consisting of thioredoxin 1 (TrxA) and thioredoxin reductase with NADPH, can reduce selenite and is considered to facilitate selenite assimilation, the detailed mechanism remains obscure. Here, we show that selenite was reduced by the thioredoxin system from only in the presence of the TrxA (PsTrxA), and this system was specific to selenite among the oxyanions examined. Mutational analysis revealed that Cys33 and Cys36 residues in PsTrxA are important for selenite reduction. Free thiol-labeling assays suggested that Cys33 is more reactive than Cys36. Mass spectrometry analysis suggested that PsTrxA reduces selenite via PsTrxA-SeO intermediate formation. Furthermore, an in vivo formate dehydrogenase activity assay in with a gene disruption suggested that TrxA is important for selenoprotein biosynthesis. The introduction of PsTrxA complemented the effects of TrxA disruption in cells, only when PsTrxA contained Cys33 and Cys36. Based on these results, we proposed the early steps of the link between selenite and selenoprotein biosynthesis via the formation of TrxA-selenium complexes.
Topics: Bacterial Proteins; Escherichia coli; Formate Dehydrogenases; Oxidation-Reduction; Pseudomonas stutzeri; Recombinant Proteins; Selenious Acid; Selenoproteins; Thioredoxins
PubMed: 34681630
DOI: 10.3390/ijms222010965 -
Journal of Medical Case Reports Oct 2021Pseudomonas stutzeri is a nonfluorescent denitrifying bacterium widely distributed in the environment, and it has also been isolated as an opportunistic pathogen from... (Review)
Review
BACKGROUND
Pseudomonas stutzeri is a nonfluorescent denitrifying bacterium widely distributed in the environment, and it has also been isolated as an opportunistic pathogen from humans. It is a Gram-negative bacterium and a common inhabitant of soil and water.
CASE PRESENTATION
We report the case of a 51-year-old arab gentleman who has systemic lupus erythematous complicated by lupus nephritis and underwent renal transplantation twice. He underwent mitral valve replacement and 4 years later was diagnosed with prosthetic valve endocarditis caused by Pseudomonas stutzeri.
CONCLUSIONS
Literature review was conducted and revealed that this pathogen may be of a particular medical relevance in immunocompromised patients. Our case proves that early infection and relapse despite optimal antibiotics course are possible outcomes of Pseudomonas stutzeri endocarditis. To the best of our knowledge, this is the second case of fulminant early prosthetic valve endocarditis occurring only 1 month post-cardiac surgery with relapse despite a complete antibiotics course.
Topics: Anti-Bacterial Agents; Endocarditis, Bacterial; Heart Valve Prosthesis; Humans; Male; Middle Aged; Pseudomonas stutzeri
PubMed: 34627386
DOI: 10.1186/s13256-021-03084-x -
The ISME Journal Mar 2022Trophic interactions play a central role in driving microbial community assembly and function. In gut or soil ecosystems, successful inoculants are always facilitated by...
Trophic interactions play a central role in driving microbial community assembly and function. In gut or soil ecosystems, successful inoculants are always facilitated by efficient colonization; however, the metabolite exchanges between inoculants and resident bacteria are rarely studied, particularly in the rhizosphere. Here, we used bioinformatic, genetic, transcriptomic, and metabonomic analyses to uncover syntrophic cooperation between inoculant (Bacillus velezensis SQR9) and plant-beneficial indigenous Pseudomonas stutzeri in the cucumber rhizosphere. We found that the synergistic interaction of these two species is highly environmental dependent, the emergence of syntrophic cooperation was only evident in a static nutrient-rich niche, such as pellicle biofilm in addition to the rhizosphere. Our results identified branched-chain amino acids (BCAAs) biosynthesis pathways are involved in syntrophic cooperation. Genome-scale metabolic modeling and metabolic profiling also demonstrated metabolic facilitation among the bacterial strains. In addition, biofilm matrix components from Bacillus were essential for the interaction. Importantly, the two-species consortium promoted plant growth and helped plants alleviate salt stress. In summary, we propose a mechanism in which synergic interactions between a biocontrol bacterium and a partner species promote plant health.
Topics: Bacillus; Microbiota; Plant Roots; Pseudomonas stutzeri; Rhizosphere; Soil Microbiology
PubMed: 34593997
DOI: 10.1038/s41396-021-01125-3 -
Molecules (Basel, Switzerland) Sep 2021Antimicrobial resistance is a dramatic global threat; however, the slow progress of new antibiotic development has impeded the identification of viable alternative...
Antimicrobial resistance is a dramatic global threat; however, the slow progress of new antibiotic development has impeded the identification of viable alternative strategies. Natural antioxidant-based antibacterial approaches may provide potent therapeutic abilities to effectively block resistance microbes' pathways. While essential oils (EOs) have been reported as antimicrobial agents, its application is still limited ascribed to its low solubility and stability characters; additionally, the related biomolecular mechanisms are not fully understood. Hence, the study aimed to develop a nano-gel natural preparation with multiple molecular mechanisms that could combat bacterial resistance in an model. A nano-emulgel of thyme/clove EOs (NEG8) was designed, standardized, and its antimicrobial activity was screened in vitro and in vivo against genetically identified skin bacterial clinical isolates (, and ). As per our findings, NEG8 exhibited bacteriostatic and potent biofilm inhibition activities. An in vivo model was also established using the commercially available therapeutic, adapalene in contra genetically identified microorganism. Improvement in rat behavior was reported for the first time and NEG8 abated the dermal contents/protein expression of IGF-1, TGF-β/collagen, Wnt/β-catenin, JAK2/STAT-3, NE, 5-HT, and the inflammatory markers; p(Ser536) NF-κBp65, TLR-2, and IL-6. Moreover, the level of dopamine, protective anti-inflammatory cytokine, IL-10 and PPAR-γ protein were enhanced, also the skin histological structures were improved. Thus, NEG8 could be a future potential topical clinical alternate to synthetic agents, with dual merit mechanism as bacteriostatic antibiotic action and non-antibiotic microbial pathway inhibitor.
Topics: Acne Vulgaris; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Behavior, Animal; Biofilms; Cues; Forkhead Transcription Factors; Insulin-Like Growth Factor I; Interleukin-6; NF-kappa B; Nanogels; PPAR gamma; Plant Extracts; Polyethylene Glycols; Polyethyleneimine; Rats; Skin; Syzygium; Thymus Plant; Toll-Like Receptor 2; Transforming Growth Factor beta; Wnt Proteins
PubMed: 34577079
DOI: 10.3390/molecules26185608 -
World Journal of Microbiology &... Sep 2021Pseudomonas stutzeri A1501 is a model strain used to study associative nitrogen fixation, and it possesses the nitrogen regulatory NtrC protein in the core genome....
Pseudomonas stutzeri A1501 is a model strain used to study associative nitrogen fixation, and it possesses the nitrogen regulatory NtrC protein in the core genome. Nitrogen sources represent one of the important factors affecting the efficiency of biological nitrogen fixation in the natural environment. However, the regulation of NtrC during nitrogen metabolism in P. stutzeri A1501 has not been clarified. In this work, a phenotypic analysis of the ntrC mutant characterized the roles of NtrC in nitrogen metabolism and the oxidative stress response of P. stutzeri A1501. To systematically identify NtrC-controlled gene expression, RNA-seq was performed to further analyse the gene expression differences between the wild-type strain and the ∆ntrC mutant under nitrogen fixation conditions. A total of 1431 genes were found to be significantly altered by ntrC deletion, among which 147 associative genes had NtrC-binding sites, and the pathways for nitrogen fixation regulation, nitrogenous compound acquisition and catabolism and nitrate assimilation were discussed. Furthermore, the oxidative stress-related gene (katB), which was upregulated by ntrC deletion, was suggested to be a potential target gene of NtrC, thus highlighting the importance of NtrC in nitrogenase protection against oxygen damage. Based on these findings, we propose that NtrC is a high-ranking element in the regulatory network of P. stutzeri A1501 that controls a variety of nitrogen metabolic and oxidative stress responsive traits required for adaptation to complex rhizosphere environments.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Mutation; Nitrogen; Nitrogen Fixation; Pseudomonas stutzeri; RNA-Seq; Rhizosphere; Transcription Factors
PubMed: 34524580
DOI: 10.1007/s11274-021-03144-w