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Microbiology Resource Announcements May 2024Extended-spectrum beta-lactamase, AmpC, and carbapenemase-producing bacteria were isolated from raw sewage, effluent, oxidation pond water, and sediment from a...
Extended-spectrum beta-lactamase, AmpC, and carbapenemase-producing bacteria were isolated from raw sewage, effluent, oxidation pond water, and sediment from a wastewater treatment plant in Aotearoa New Zealand. Here, we report the assemblies of 17 isolates belonging to the species , , , , , , , , , and .
PubMed: 38564672
DOI: 10.1128/mra.00131-24 -
BMC Veterinary Research Apr 2024Pseudomonas putida is a pathogenic bacterium that induces great losses in fishes, including Nile tilapia (Oreochromis niloticus). Currently, the application of...
Pseudomonas putida infection induces immune-antioxidant, hepato-renal, ethological, and histopathological/immunohistochemical disruptions in Oreochromis niloticus: the palliative role of titanium dioxide nanogel.
BACKGROUND
Pseudomonas putida is a pathogenic bacterium that induces great losses in fishes, including Nile tilapia (Oreochromis niloticus). Currently, the application of nanomaterials in aquaculture practices has gained more success as it endows promising results in therapies compared to traditional protocols.
OBJECTIVE
Therefore, the current perspective is considered the first report to assess the anti-bacterial efficacy of titanium dioxide nanogel (TDNG) against Pseudomonas putida (P. putida) in Nile tilapia.
METHODS
The fish (n = 200; average body weight: 47.50±1.32 g) were allocated into four random groups (control, TDNG, P. putida, and TDNG + P. putida), where 0.9 mg/L of TDNG was applied as bath treatment for ten days.
RESULTS
Outcomes revealed that P. putida infection caused ethological alterations (surfacing, abnormal movement, and aggression) and depression of immune-antioxidant variables (complement 3, lysozyme activity, total antioxidant capacity, superoxide dismutase, and reduced glutathione content). Additionally, a substantial elevation in hepatorenal biomarkers (aspartate and alanine aminotransferases and creatinine) with clear histopathological changes and immuno-histochemical alterations (very weak BCL-2 and potent caspase-3 immuno-expressions) were seen. Surprisingly, treating P. putida-infected fish with TDNG improved these variables and obvious restoration of the tissue architectures.
CONCLUSION
Overall, this report encompasses the key role of TDNG as an anti-bacterial agent for controlling P. putida infection and improving the health status of Nile tilapia.
Topics: Animals; Antioxidants; Pseudomonas putida; Cichlids; Nanogels; Diet; Dietary Supplements; Animal Feed; Fish Diseases; Polyethylene Glycols; Polyethyleneimine; Titanium
PubMed: 38561720
DOI: 10.1186/s12917-024-03972-6 -
Microorganisms Mar 2024The establishment of sustainable processes for the production of commodity chemicals is one of today's central challenges for biotechnological industries. The...
The establishment of sustainable processes for the production of commodity chemicals is one of today's central challenges for biotechnological industries. The chemo-autotrophic fixation of CO and the subsequent production of acetate by acetogenic bacteria via anaerobic gas fermentation represents a promising platform for the ecologically sustainable production of high-value biocommodities via sequential fermentation processes. In this study, the applicability of acetate-containing cell-free spent medium of the gas-fermenting acetogenic bacterium WP1 as the feeder strain for growth and the recombinant production of PAO1 mono-rhamnolipids in the well-established nonpathogenic producer strain KT2440 were investigated. Additionally, the potential possibility of a simplified production process without the necessary separation of feeder strain cells was elucidated via the cultivation of in cell-containing culture broth. For these cultures, the content of both strains was investigated by examining the relative quantification of strain-exclusive genes via qPCR. The recombinant production of mono-rhamnolipids was successfully achieved with maximum titers of approximately 360-400 mg/L for both cell-free and cell-containing spent medium. The reported processes therefore represent a successful proof of principle for gas fermentation-derived acetate as a potential sustainable carbon source for future recombinant rhamnolipid production processes by KT2440.
PubMed: 38543580
DOI: 10.3390/microorganisms12030529 -
Nature Communications Mar 2024To broaden the substrate scope of microbial cell factories towards renewable substrates, rational genetic interventions are often combined with adaptive laboratory...
To broaden the substrate scope of microbial cell factories towards renewable substrates, rational genetic interventions are often combined with adaptive laboratory evolution (ALE). However, comprehensive studies enabling a holistic understanding of adaptation processes primed by rational metabolic engineering remain scarce. The industrial workhorse Pseudomonas putida was engineered to utilize the non-native sugar D-xylose, but its assimilation into the bacterial biochemical network via the exogenous xylose isomerase pathway remained unresolved. Here, we elucidate the xylose metabolism and establish a foundation for further engineering followed by ALE. First, native glycolysis is derepressed by deleting the local transcriptional regulator gene hexR. We then enhance the pentose phosphate pathway by implanting exogenous transketolase and transaldolase into two lag-shortened strains and allow ALE to finetune the rewired metabolism. Subsequent multilevel analysis and reverse engineering provide detailed insights into the parallel paths of bacterial adaptation to the non-native carbon source, highlighting the enhanced expression of transaldolase and xylose isomerase along with derepressed glycolysis as key events during the process.
Topics: Xylose; Pseudomonas putida; Transaldolase; Metabolic Engineering; Pentose Phosphate Pathway
PubMed: 38531855
DOI: 10.1038/s41467-024-46812-9 -
Microbial Biotechnology Mar 2024Medium-chain-length α,ω-diols (mcl-diols) play an important role in polymer production, traditionally depending on energy-intensive chemical processes. Microbial cell...
Medium-chain-length α,ω-diols (mcl-diols) play an important role in polymer production, traditionally depending on energy-intensive chemical processes. Microbial cell factories offer an alternative, but conventional strains like Escherichia coli and Saccharomyces cerevisiae face challenges in mcl-diol production due to the toxicity of intermediates such as alcohols and acids. Metabolic engineering and synthetic biology enable the engineering of non-model strains for such purposes with P. putida emerging as a promising microbial platform. This study reviews the advancement in diol production using P. putida and proposes a four-module approach for the sustainable production of diols. Despite progress, challenges persist, and this study discusses current obstacles and future opportunities for leveraging P. putida as a microbial cell factory for mcl-diol production. Furthermore, this study highlights the potential of using P. putida as an efficient chassis for diol synthesis.
Topics: Pseudomonas putida; Polyhydroxyalkanoates; Metabolic Engineering; Escherichia coli; Synthetic Biology
PubMed: 38528784
DOI: 10.1111/1751-7915.14423 -
Methods in Molecular Biology (Clifton,... 2024The vast number of unknown phage-encoded ORFan genes and limited insights into the genome organization of phages illustrate the need for efficient genome engineering...
The vast number of unknown phage-encoded ORFan genes and limited insights into the genome organization of phages illustrate the need for efficient genome engineering tools to study bacteriophage genes in their natural context. In addition, there is an application-driven desire to alter phage properties, which is hampered by time constraints for phage genome engineering in the bacterial host. We here describe an optimized CRISPR-Cas3 system in Pseudomonas for straightforward editing of the genome of virulent bacteriophages. The two-vector system combines a broad host range CRISPR-Cas3 targeting plasmid with a SEVA plasmid for homologous directed repair, which enables the creation of clean deletions, insertions, or substitutions in the phage genome within a week. After creating the two plasmids separately, a co-transformation to P. aeruginosa cells is performed. A subsequent infection with the targeted phage allows the CRISPR-Cas3 system to cut the DNA specifically and facilitate or select for homologous recombination. This system has also been successfully applied for P. aeruginosa and Pseudomonas putida genome engineering. The method is straightforward, efficient, and universal, enabling to extrapolate the system to other phage-host pairs.
Topics: Gene Editing; Pseudomonas Phages; CRISPR-Cas Systems; Bacteriophages; Homologous Recombination
PubMed: 38526727
DOI: 10.1007/978-1-0716-3798-2_8 -
Cell Reports Apr 2024Bacterial polyhydroxyalkanoates (PHAs) have emerged as promising eco-friendly alternatives to petroleum-based plastics since they are synthesized from renewable...
Bacterial polyhydroxyalkanoates (PHAs) have emerged as promising eco-friendly alternatives to petroleum-based plastics since they are synthesized from renewable resources and offer exceptional properties. However, their production is limited to the stationary growth phase under nutrient-limited conditions, requiring customized strategies and costly two-phase bioprocesses. In this study, we tackle these challenges by employing a model-driven approach to reroute carbon flux and remove regulatory constraints using synthetic biology. We construct a collection of Pseudomonas putida-overproducing strains at the expense of plastics and lignin-related compounds using growth-coupling approaches. PHA production was successfully achieved during growth phase, resulting in the production of up to 46% PHA/cell dry weight while maintaining a balanced carbon-to-nitrogen ratio. Our strains are additionally validated under an upcycling scenario using enzymatically hydrolyzed polyethylene terephthalate as a feedstock. These findings have the potential to revolutionize PHA production and address the global plastic crisis by overcoming the complexities of traditional PHA production bioprocesses.
Topics: Pseudomonas putida; Polyhydroxyalkanoates; Nutrients; Carbon; Nitrogen; Polyethylene Terephthalates
PubMed: 38517887
DOI: 10.1016/j.celrep.2024.113979 -
Gene expression reprogramming of in response to arginine through the transcriptional regulator ArgR.Microbiology (Reading, England) Mar 2024Different bacteria change their life styles in response to specific amino acids. In (now ) KT2440, arginine acts both as an environmental and a metabolic indicator that...
Different bacteria change their life styles in response to specific amino acids. In (now ) KT2440, arginine acts both as an environmental and a metabolic indicator that modulates the turnover of the intracellular second messenger c-di-GMP, and expression of biofilm-related genes. The transcriptional regulator ArgR, belonging to the AraC/XylS family, is key for the physiological reprogramming in response to arginine, as it controls transport and metabolism of the amino acid. To further expand our knowledge on the roles of ArgR, a global transcriptomic analysis of KT2440 and a null mutant growing in the presence of arginine was carried out. Results indicate that this transcriptional regulator influences a variety of cellular functions beyond arginine metabolism and transport, thus widening its regulatory role. ArgR acts as positive or negative modulator of the expression of several metabolic routes and transport systems, respiratory chain and stress response elements, as well as biofilm-related functions. The partial overlap between the ArgR regulon and those corresponding to the global regulators RoxR and ANR is also discussed.
Topics: Arginine; Repressor Proteins; Pseudomonas; Gene Expression; Bacterial Proteins; Gene Expression Regulation, Bacterial
PubMed: 38511653
DOI: 10.1099/mic.0.001449 -
Environmental Pollution (Barking, Essex... May 2024Currently, the selection of non-pathogenic microorganisms that lack clinically relevant antimicrobial resistance is crucial to bioaugmentation strategies. Pseudomonas...
Currently, the selection of non-pathogenic microorganisms that lack clinically relevant antimicrobial resistance is crucial to bioaugmentation strategies. Pseudomonas sp. P26 (P26) is an environmental bacterium of interest due to its ability to remove aromatic compounds from petroleum, but its safety characteristics are still unknown. The study aimed to: a) determine P26 sensitivity to antimicrobials, b) investigate the presence of quinolone and β-lactam resistance genes, c) determine the presence of virulence factors, and d) evaluate the effect of P26 on the viability of Galleria mellonella (an invertebrate animal model). P26 antimicrobial sensitivity was determined in vitro using the Kirby-Bauer agar diffusion method and the VITEK 2 automated system (BioMerieux®). Polymerase Chain Reaction was employed for the investigation of genes associated with quinolone resistance, extended-spectrum β-lactamases, and carbapenemases. Hemolysin and protease production was determined in human blood agar and skimmed-milk agar, respectively. In the in vivo assay, different doses of P26 were injected into Galleria mellonella larvae and their survival was monitored daily. Control larvae injected with Pseudomonas putida KT2440 (a strain considered as safe) and Pseudomonas aeruginosa PA14 (a pathogenic strain) were included. Pseudomonas sp. P26 was susceptible to most evaluated antimicrobials, except for trimethoprim-sulfamethoxazole. No epidemiologically relevant genes associated with quinolone and β-lactam resistance were identified. Hemolysin and protease production was only evidenced in the virulent strain (PA14). Furthermore, the results obtained in the in vivo experiment demonstrated that inocula less than 10 CFU/mL of P26 and P. putida KT2440 did not significantly affect larval survival, whereas larvae injected with the lowest dose of the pathogenic strain P. aeruginosa PA14 experienced instant mortality. The results suggest that Pseudomonas sp. P26 is a safe strain for its application in environmental bioremediation processes. Additional studies will be conducted to ensure the safety of this bacterium against other organisms.
Topics: Animals; Humans; Pseudomonas; Agar; Hemolysin Proteins; Moths; Larva; Pseudomonas aeruginosa; Anti-Infective Agents; Peptide Hydrolases; Quinolones; Anti-Bacterial Agents
PubMed: 38508367
DOI: 10.1016/j.envpol.2024.123818 -
Microbial Biotechnology Mar 2024Pseudomonas putida is a soil bacterium with multiple uses in fermentation and biotransformation processes. P. putida ATCC 12633 can biotransform benzaldehyde and other...
Pseudomonas putida is a soil bacterium with multiple uses in fermentation and biotransformation processes. P. putida ATCC 12633 can biotransform benzaldehyde and other aldehydes into valuable α-hydroxyketones, such as (S)-2-hydroxypropiophenone. However, poor tolerance of this strain toward chaotropic aldehydes hampers efficient biotransformation processes. To circumvent this problem, we expressed the gene encoding the global regulator PprI from Deinococcus radiodurans, an inducer of pleiotropic proteins promoting DNA repair, in P. putida. Fine-tuned gene expression was achieved using an expression plasmid under the control of the LacI /P system, and the cross-protective role of PprI was assessed against multiple stress treatments. Moreover, the stress-tolerant P. putida strain was tested for 2-hydroxypropiophenone production using whole resting cells in the presence of relevant aldehyde substrates. P. putida cells harbouring the global transcriptional regulator exhibited high tolerance toward benzaldehyde, acetaldehyde, ethanol, butanol, NaCl, H O and thermal stress, thereby reflecting the multistress protection profile conferred by PprI. Additionally, the engineered cells converted aldehydes to 2-hydroxypropiophenone more efficiently than the parental P. putida strain. 2-Hydroxypropiophenone concentration reached 1.6 g L upon a 3-h incubation under optimized conditions, at a cell concentration of 0.033 g wet cell weight mL in the presence of 20 mM benzaldehyde and 600 mM acetaldehyde. Product yield and productivity were 0.74 g 2-HPP g benzaldehyde and 0.089 g 2-HPP g cell dry weight h , respectively, 35% higher than the control experiments. Taken together, these results demonstrate that introducing PprI from D. radiodurans enhances chaotrope tolerance and 2-HPP production in P. putida ATCC 12633.
Topics: Benzaldehydes; Pseudomonas putida; Deinococcus; Hydroxypropiophenone; Acetaldehyde
PubMed: 38498302
DOI: 10.1111/1751-7915.14448