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Environmental Microbiology Jul 2022
Topics: Fluorocarbons; Pseudomonas
PubMed: 35384226
DOI: 10.1111/1462-2920.15990 -
Bioresource Technology Jan 2021The most prominent aromatic feedstock on Earth is lignin, however, lignin valorization is still an underrated subject. The principal preparatory strategies for lignin... (Review)
Review
The most prominent aromatic feedstock on Earth is lignin, however, lignin valorization is still an underrated subject. The principal preparatory strategies for lignin valorization are fragmentation and depolymerization which help in the production of fuels and chemicals. Owing to lignin's structural heterogeneity, these strategies result in product generation which requires tedious separation and purification to extract target products. The bacterial genus Pseudomonas has been dominant for its lignin valorization potency, owing to a robust enzymatic machinery that is used to funnel variable lignin derivatives into certain target products such as polyhydroxyalkanotes (PHAs) and cis, cis-muconic acid (MA). In this review, the potential of genus Pseudomonas in lignin valorization is critically reviewed along with the advanced genetic techniques and tools to ease the use of lignin/lignin-model compounds for the synthesis of bioproducts. This review also highlights the research gaps in lignin biovalorization and discuss the challenges and possibilities for future research.
Topics: Lignin; Pseudomonas
PubMed: 33249259
DOI: 10.1016/j.biortech.2020.124412 -
Annals of Clinical Microbiology and... Mar 2022The carbapenem-resistance genes bla are widely disseminated in Pseudomonas, and frequently harbored within class 1 integrons that reside within various mobile genetic...
BACKGROUND
The carbapenem-resistance genes bla are widely disseminated in Pseudomonas, and frequently harbored within class 1 integrons that reside within various mobile genetic elements (MGEs). However, there are few reports on detailed genetic dissection of bla-carrying MGEs in Pseudomonas.
METHODS
This study presented the complete sequences of five bla-carrying MGEs, including two plasmids, two chromosomal integrative and mobilizable elements (IMEs), and one chromosomal integrative and conjugative element (ICE) from five different Pseudomonas isolates.
RESULTS
The two plasmids were assigned to a novel incompatibility (Inc) group Inc, which included only seven available plasmids with determined complete sequences and could be further divided into three subgroups Inc-1/2/3. A detailed sequence comparison was then applied to a collection of 15 MGEs belonging to four different groups: three representative Inc plasmids, two Tn6916-related IMEs, two Tn6918-related IMEs, and eight Tn6417-related ICEs and ten of these 15 MGEs were first time identified. At least 22 genes involving resistance to seven different categories of antibiotics and heavy metals were identified within these 15 MGEs, and most of these resistance genes were located within the accessory modules integrated as exogenous DNA regions into these MGEs. Especially, eleven of these 15 MGEs carried the bla genes, which were located within 11 different concise class 1 integrons.
CONCLUSION
These bla-carrying integrons were further integrated into the above plasmids, IMEs/ICEs with intercellular mobility. These MGEs could transfer between Pseudomonas isolates, which resulted in the accumulation and spread of bla among Pseudomonas and thus was helpful for the bacteria to survival from the stress of antibiotics. Data presented here provided a deeper insight into the genetic diversification and evolution of VIM-encoding MGEs in Pseudomonas.
Topics: Anti-Bacterial Agents; Chromosomes, Bacterial; Conjugation, Genetic; Integrons; Plasmids; Pseudomonas; beta-Lactamases
PubMed: 35264204
DOI: 10.1186/s12941-022-00502-w -
Scientific Reports Jun 2024A novel nano bio-fertilizer encapsulation method was developed to crosslink chitosan and alginate with humic acid. These nanocapsules, referred to as (Ch./Alg.HA.NPK) or...
A novel nano bio-fertilizer encapsulation method was developed to crosslink chitosan and alginate with humic acid. These nanocapsules, referred to as (Ch./Alg.HA.NPK) or (Ch./Alg.HA.NPK.PGPRs), were loaded with nanoscale essential agro-nutrients (NPK) and beneficial microorganisms Pseudomonas Fluorescence abbreviated as (P.Fluorescence). Structural and morphological analyses were conducted using FourierTransform Infrared, Thermogravimetric Analysis, Scanning Electron Microscopy, Malvern Zeta NanoSizer, and Zeta potential. Encapsulation efficiency and water retention were also determined compared to control non-crosslinked nanocapsules. The sustained cumulative release of NPK over 30 days was also investigated to 33.2%, 47.8%, and 68.3%, alternatively. The release mechanism, also assessed through the kinetic module of the Korsemeyer- Peppas Mathematical model, demonstrated superior performance compared to non-crosslinked nanocapsules (chitosan/alginate). These results show the potential of the synthesized nanocapsules for environmentally conscious controlled release of NPK and PGPRs, thereby mitigating environmental impact, enhancing plant growth, and reducing reliance on conventional agrochemical fertilizers.
Topics: Fertilizers; Chitosan; Agriculture; Alginates; Nanocapsules; Humic Substances; Pseudomonas
PubMed: 38871758
DOI: 10.1038/s41598-024-62973-5 -
Frontiers in Cellular and Infection... 2021and infections frequently co-localize in lungs of immunocompromised patients and individuals with cystic fibrosis (CF). The antifungal activity of has been described...
and infections frequently co-localize in lungs of immunocompromised patients and individuals with cystic fibrosis (CF). The antifungal activity of has been described for its filtrates. Pyoverdine and pyocyanin are the principal antifungal molecules active against biofilm metabolism present in iron-limited or iron-replete planktonic culture filtrates, respectively. Using various laboratory wild-type strains (PA14, PAO1, PAK), we found antifungal activity against colonies on agar. Comparing 36 PA14 and 7 PAO1 mutants, we found that mutants lacking both major siderophores, pyoverdine and pyochelin, display higher antifungal activity on agar than their wild types, while quorum sensing mutants lost antifungal activity. Addition of ferric iron, but not calcium or magnesium, reduced the antifungal effects of on agar, whereas iron-poor agar enhanced antifungal effects. Antifungal activity on agar was mediated by PQS and HHQ, MvfR. Among the MvfR downstream factors, rhamnolipids and elastase were produced in larger quantities by pyoverdine-pyochelin double mutants and showed antifungal activity on agar. In summary, antifungal factors produced by on agar differ from those produced by bacteria grown in liquid cultures, are dependent on quorum sensing, and are downregulated by the availability of ferric iron. Rhamnolipids and elastase seem to be major mediators of ' antifungal activity on a solid surface.
Topics: Aspergillus; Biofilms; Humans; Pseudomonas; Pseudomonas Infections; Pseudomonas aeruginosa; Pyocyanine; Quorum Sensing
PubMed: 34746024
DOI: 10.3389/fcimb.2021.734296 -
Scientific Reports Apr 2023Biodesulfurization (BDS) was employed in this study to degrade dibenzothiophene (DBT) which accounts for 70% of the sulfur compounds in diesel using a synthetic and...
Biodesulfurization (BDS) was employed in this study to degrade dibenzothiophene (DBT) which accounts for 70% of the sulfur compounds in diesel using a synthetic and typical South African diesel in the aqueous and biphasic medium. Two Pseudomonas sp. bacteria namely Pseudomonas aeruginosa and Pseudomonas putida were used as biocatalysts. The desulfurization pathways of DBT by the two bacteria were determined by gas chromatography (GC)/mass spectrometry (MS) and High-Performance Liquid Chromatography (HPLC). Both organisms were found to produce 2-hydroxy biphenyl, the desulfurized product of DBT. Results showed BDS performance of 67.53% and 50.02%, by Pseudomonas aeruginosa and Pseudomonas putida, respectively for 500 ppm initial DBT concentration. In order to study the desulfurization of diesel oils obtained from an oil refinery, resting cells studies by Pseudomonas aeruginosa were carried out which showed a decrease of about 30% and 70.54% DBT removal for 5200 ppm in hydrodesulfurization (HDS) feed diesel and 120 ppm in HDS outlet diesel, respectively. Pseudomonas aeruginosa and Pseudomonas putida selectively degraded DBT to form 2-HBP. Application of these bacteria for the desulfurization of diesel showed promising potential for decreasing the sulfur content of South African diesel oil.
Topics: Pseudomonas; Petroleum; Thiophenes; Sulfur Compounds; Gasoline; Pseudomonas putida; Pseudomonas aeruginosa; Biodegradation, Environmental
PubMed: 37055435
DOI: 10.1038/s41598-023-31951-8 -
The ISME Journal Oct 2023Proteobacteria primarily utilize acyl-homoserine lactones (AHLs) as quorum-sensing signals for intra-/interspecies communication to control pathogen infections....
Proteobacteria primarily utilize acyl-homoserine lactones (AHLs) as quorum-sensing signals for intra-/interspecies communication to control pathogen infections. Enzymatic degradation of AHL represents the major quorum-quenching mechanism that has been developed as a promising approach to prevent bacterial infections. Here we identified a novel quorum-quenching mechanism revealed by an effector of the type IVA secretion system (T4ASS) in bacterial interspecies competition. We found that the soil antifungal bacterium Lysobacter enzymogenes OH11 (OH11) could use T4ASS to deliver the effector protein Le1288 into the cytoplasm of another soil microbiome bacterium Pseudomonas fluorescens 2P24 (2P24). Le1288 did not degrade AHL, whereas its delivery to strain 2P24 significantly impaired AHL production through binding to the AHL synthase PcoI. Therefore, we defined Le1288 as LqqE1 (Lysobacter quorum-quenching effector 1). Formation of the LqqE1-PcoI complex enabled LqqE1 to block the ability of PcoI to recognize/bind S-adenosy-L-methionine, a substrate required for AHL synthesis. This LqqE1-triggered interspecies quorum-quenching in bacteria seemed to be of key ecological significance, as it conferred strain OH11 a better competitive advantage in killing strain 2P24 via cell-to-cell contact. This novel quorum-quenching also appeared to be adopted by other T4ASS-production bacteria. Our findings suggest a novel quorum-quenching that occurred naturally in bacterial interspecies interactions within the soil microbiome by effector translocation. Finally, we presented two case studies showing the application potential of LqqE1 to block AHL signaling in the human pathogen Pseudomonas aeruginosa and the plant pathogen Ralstonia solanacearum.
Topics: Humans; Quorum Sensing; Bacterial Proteins; Pseudomonas; Pseudomonas aeruginosa; Acyl-Butyrolactones; Pseudomonas fluorescens
PubMed: 37340074
DOI: 10.1038/s41396-023-01457-2 -
Applied Microbiology and Biotechnology Aug 2023The biocatalysis of β-myrcene into value-added compounds, with enhanced organoleptic/therapeutic properties, may be performed by resorting to specialized enzymatic...
The biocatalysis of β-myrcene into value-added compounds, with enhanced organoleptic/therapeutic properties, may be performed by resorting to specialized enzymatic machinery of β-myrcene-biotransforming bacteria. Few β-myrcene-biotransforming bacteria have been studied, limiting the diversity of genetic modules/catabolic pathways available for biotechnological research. In our model Pseudomonas sp. strain M1, the β-myrcene catabolic core-code was identified in a 28-kb genomic island (GI). The lack of close homologs of this β-myrcene-associated genetic code prompted a bioprospection of cork oak and eucalyptus rhizospheres, from 4 geographic locations in Portugal, to evaluate the environmental diversity and dissemination of the β-myrcene-biotransforming genetic trait (Myr). Soil microbiomes were enriched in β-myrcene-supplemented cultures, from which β-myrcene-biotransforming bacteria were isolated, belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Sphingobacteriia classes. From a panel of representative Myr isolates that included 7 bacterial genera, the production of β-myrcene derivatives previously reported in strain M1 was detected in Pseudomonas spp., Cupriavidus sp., Sphingobacterium sp., and Variovorax sp. A comparative genomics analysis against the genome of strain M1 found the M1-GI code in 11 new Pseudomonas genomes. Full nucleotide conservation of the β-myrcene core-code was observed throughout a 76-kb locus in strain M1 and all 11 Pseudomonas spp., resembling the structure of an integrative and conjugative element (ICE), despite being isolated from different niches. Furthermore, the characterization of isolates not harboring the Myr-related 76-kb locus suggested that they may biotransform β-myrcene via alternative catabolic loci, being thereby a novel source of enzymes and biomolecule catalogue for biotechnological exploitation. KEY POINTS: • The isolation of 150 Myr bacteria hints the ubiquity of such trait in the rhizosphere. • The Myr trait is spread across different bacterial taxonomic classes. • The core-code for the Myr trait was detected in a novel ICE, only found in Pseudomonas spp.
Topics: Rhizosphere; Acyclic Monoterpenes; Bacteria; Pseudomonas
PubMed: 37405434
DOI: 10.1007/s00253-023-12650-w -
Bioresource Technology Jan 2021Bio-based rhamnolipid production from waste streams is gaining momentum nowadays because of increasing market demand, huge range of applications and its economic and... (Review)
Review
Bio-based rhamnolipid production from waste streams is gaining momentum nowadays because of increasing market demand, huge range of applications and its economic and environment friendly nature. Rhamnolipid type biosurfactants are produced by microorganisms as secondary metabolites and have been used to reduce surface/interfacial tension between two different phases. Biosurfactants have been reported to be used as an alternative to chemical surfactants. Pseudomonas sp. has been frequently used for production of rhamnolipid. Various wastes can be used in production of rhamnolipid. Rhamnolipids are widely used in various industrial applications. The present review provides information about structure and nature of rhamnolipid, production using different waste materials and scale-up of rhamnolipid production. It also provides comprehensive literature on various industrial applications along with perspectives and challenges in this research area.
Topics: Glycolipids; Pseudomonas; Pseudomonas aeruginosa; Surface Tension; Surface-Active Agents; Waste Products
PubMed: 33254448
DOI: 10.1016/j.biortech.2020.124213 -
Environmental Microbiology Apr 2023KaiC is the central cog of the circadian clock in Cyanobacteria. Close homologues of this protein are widespread among nonphotosynthetic bacteria, but the function,...
KaiC is the central cog of the circadian clock in Cyanobacteria. Close homologues of this protein are widespread among nonphotosynthetic bacteria, but the function, interaction network, and mechanism of action of these proteins are still largely unknown. Here, we focus on KaiC homologues found in environmental Pseudomonas species. Using bioinformatics, we describe the distribution of this protein family in the genus and reveal a conserved interaction network comprising a histidine kinase and response regulator. We characterize experimentally the only KaiC homologue present in Pseudomonas putida KT2440 and Pseudomonas protegens CHA0. Through phenotypic assays and transcriptomics, we show that KaiC is involved in osmotic and oxidative stress resistance in P. putida and in biofilm production in both species. KaiC homologues are found in different phosphorylation states and physically interact with a cognate histidine kinase and response regulator. In contrast with cyanobacterial counterparts, the expression and phosphorylation of KaiC homologues do not correlate with light variations under 12:12 light: dark cycles in either Pseudomonas species, and KaiC itself is not required to support a light-driven behaviour in P. putida. Overall, this suggests that KaiC homologues in Pseudomonas species are involved in environmental stress resistance but not in responses to diurnal rhythms.
Topics: Bacterial Proteins; Histidine Kinase; Circadian Rhythm Signaling Peptides and Proteins; Circadian Rhythm; Cyanobacteria; Phosphorylation; Pseudomonas
PubMed: 36579711
DOI: 10.1111/1462-2920.16330