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Microbial Cell Factories Mar 2021Rhamnolipids have recently attracted considerable attentions because of their excellent biosurfactant performance and potential applications in agriculture, environment,... (Review)
Review
Rhamnolipids have recently attracted considerable attentions because of their excellent biosurfactant performance and potential applications in agriculture, environment, biomedicine, etc., but severe foaming causes the high cost of production, restraining their commercial production and applications. To reduce or eliminate the foaming, numerous explorations have been focused on foaming factors and fermentation strategies, but a systematic summary and discussion are still lacking. Additionally, although these studies have not broken through the bottleneck of foaming, they are conducive to understanding the foaming mechanism and developing more effective rhamnolipids production strategies. Therefore, this review focuses on the effects of fermentation components and control conditions on foaming behavior and fermentation strategies responded to the severe foaming in rhamnolipids fermentation and systematically summarizes 6 impact factors and 9 fermentation strategies. Furthermore, the potentialities of 9 fermentation strategies for large-scale production are discussed and some further strategies are suggested. We hope this review can further facilitate the understanding of foaming factors and fermentation strategies as well as conducive to developing the more effective large-scale production strategies to accelerate the commercial production process of rhamnolipids.
Topics: Fermentation; Glycolipids; Industrial Microbiology; Pseudomonas aeruginosa; Surface-Active Agents
PubMed: 33781264
DOI: 10.1186/s12934-021-01516-3 -
International Journal of Molecular... Sep 2022Pyoverdines (PVDs) are a class of siderophores produced mostly by members of the genus . Their primary function is to accumulate, mobilize, and transport iron necessary... (Review)
Review
Pyoverdines (PVDs) are a class of siderophores produced mostly by members of the genus . Their primary function is to accumulate, mobilize, and transport iron necessary for cell metabolism. Moreover, PVDs also play a crucial role in microbes' survival by mediating biofilm formation and virulence. In this review, we reorganize the information produced in recent years regarding PVDs biosynthesis and pathogenic mechanisms, since PVDs are extremely valuable compounds. Additionally, we summarize the therapeutic applications deriving from the PVDs' use and focus on their role as therapeutic target themselves. We assess the current biotechnological applications of different sectors and evaluate the state-of-the-art technology relating to the use of synthetic biology tools for pathway engineering. Finally, we review the most recent methods and techniques capable of identifying such molecules in complex matrices for drug-discovery purposes.
Topics: Iron; Oligopeptides; Pseudomonas; Pseudomonas aeruginosa; Siderophores
PubMed: 36232800
DOI: 10.3390/ijms231911507 -
Biometals : An International Journal on... Aug 2023Iron is important for bacterial growth and survival, as it is a common co-factor in essential enzymes. Although iron is very abundant in the earth crust, its... (Review)
Review
Iron is important for bacterial growth and survival, as it is a common co-factor in essential enzymes. Although iron is very abundant in the earth crust, its bioavailability is low in most habitats because ferric iron is largely insoluble under aerobic conditions and at neutral pH. Consequently, bacteria have evolved a plethora of mechanisms to solubilize and acquire iron from environmental and host stocks. In this review, I focus on Pseudomonas spp. and first present the main iron uptake mechanisms of this taxa, which involve the direct uptake of ferrous iron via importers, the production of iron-chelating siderophores, the exploitation of siderophores produced by other microbial species, and the use of iron-chelating compounds produced by plants and animals. In the second part of this review, I elaborate on how these mechanisms affect interactions between bacteria in microbial communities, and between bacteria and their hosts. This is important because Pseudomonas spp. live in diverse communities and certain iron-uptake strategies might have evolved not only to acquire this essential nutrient, but also to gain relative advantages over competitors in the race for iron. Thus, an integrative understanding of the mechanisms of iron acquisition and the eco-evolutionary dynamics they drive at the community level might prove most useful to understand why Pseudomonas spp., in particular, and many other bacterial species, in general, have evolved such diverse iron uptake repertoires.
Topics: Animals; Siderophores; Iron; Iron Chelating Agents; Pseudomonas; Bacteria
PubMed: 36508064
DOI: 10.1007/s10534-022-00480-8 -
Metabolic Engineering Jul 2021Over 359 million tons of plastics were produced worldwide in 2018, with significant growth expected in the near future, resulting in the global challenge of end-of-life...
Over 359 million tons of plastics were produced worldwide in 2018, with significant growth expected in the near future, resulting in the global challenge of end-of-life management. The recent identification of enzymes that degrade plastics previously considered non-biodegradable opens up opportunities to steer the plastic recycling industry into the realm of biotechnology. Here, the sequential conversion of post-consumer polyethylene terephthalate (PET) into two types of bioplastics is presented: a medium chain-length polyhydroxyalkanoate (PHA) and a novel bio-based poly(amide urethane) (bio-PU). PET films are hydrolyzed by a thermostable polyester hydrolase yielding highly pure terephthalate and ethylene glycol. The obtained hydrolysate is used directly as a feedstock for a terephthalate-degrading Pseudomonas umsongensis GO16, also evolved to efficiently metabolize ethylene glycol, to produce PHA. The strain is further modified to secrete hydroxyalkanoyloxy-alkanoates (HAAs), which are used as monomers for the chemo-catalytic synthesis of bio-PU. In short, a novel value-chain for PET upcycling is shown that circumvents the costly purification of PET monomers, adding technological flexibility to the global challenge of end-of-life management of plastics.
Topics: Hydrolases; Plastics; Polyethylene Terephthalates; Pseudomonas
PubMed: 33865980
DOI: 10.1016/j.ymben.2021.03.011 -
Clinical Microbiology and Infection :... Mar 2020Pseudomonas aeruginosa is one of the most common pathogens isolated from respiratory tract specimen in patients with bronchiectasis. It is considered highly responsible... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Pseudomonas aeruginosa is one of the most common pathogens isolated from respiratory tract specimen in patients with bronchiectasis. It is considered highly responsible for pathogenicity, progression and clinical outcomes of bronchiectasis.
AIMS
To summarize existing evidence on how different factors of Pseudomonas aeruginosa affect the pathogenicity, progression and clinical outcomes of bronchiectasis, so as to provide possible insights for clinical practice and related research in the future.
SOURCES
PubMed was searched for studies pertaining to bronchiectasis and P. aeruginosa published to date, with no specific inclusion or exclusion criteria. Reference lists of retrieved reviews were searched for additional articles.
CONTENT
This review focused on non-cystic fibrosis bronchiectasis and also provided some data on cystic fibrosis when studies in bronchiectasis were limited. We discussed various factors in relation to P. aeruginosa: virulence factors, drug resistance, regulatory systems, genomic diversity and transmission of P. aeruginosa, as well as treatment for P. aeruginosa. Their impacts on bronchiectasis and its management were discussed.
IMPLICATIONS
The impact of P. aeruginosa on bronchiectasis is definite, although conclusions in some aspects are still vague. Faced with the worrying drug-resistance status and treatment bottleneck, individualized management and novel therapies beyond the classic pathway are most likely to be a future trend. To confirm the independent or integrated impact of various factors of P. aeruginosa on bronchiectasis and to figure out all the problems mentioned, larger randomized control trials are truly needed in the future.
Topics: Anti-Bacterial Agents; Bronchiectasis; Clinical Decision-Making; Disease Management; Disease Progression; Disease Susceptibility; Drug Resistance, Bacterial; Genetic Variation; Genome, Bacterial; Humans; Patient Outcome Assessment; Pseudomonas Infections; Pseudomonas aeruginosa; Virulence Factors
PubMed: 31306794
DOI: 10.1016/j.cmi.2019.07.010 -
Proceedings of the National Academy of... Oct 2023Energy conversion by electron transport chains occurs through the sequential transfer of electrons between protein complexes and intermediate electron carriers, creating...
Energy conversion by electron transport chains occurs through the sequential transfer of electrons between protein complexes and intermediate electron carriers, creating the proton motive force that enables ATP synthesis and membrane transport. These protein complexes can also form higher order assemblies known as respiratory supercomplexes (SCs). The electron transport chain of the opportunistic pathogen is closely linked with its ability to invade host tissue, tolerate harsh conditions, and resist antibiotics but is poorly characterized. Here, we determine the structure of a SC that forms between the quinol:cytochrome oxidoreductase (cytochrome ) and one of the organism's terminal oxidases, cytochrome , which is found only in some bacteria. Remarkably, the SC structure also includes two intermediate electron carriers: a diheme cytochrome and a single heme cytochrome . Together, these proteins allow electron transfer from ubiquinol in cytochrome to oxygen in cytochrome . We also present evidence that different isoforms of cytochrome can participate in formation of this SC without changing the overall SC architecture. Incorporating these different subunit isoforms into the SC would allow the bacterium to adapt to different environmental conditions. Bioinformatic analysis focusing on structural motifs in the SC suggests that cytochrome - SCs also exist in other bacterial pathogens.
Topics: Pseudomonas aeruginosa; Electron Transport; Biological Transport; Cytochromes c; Anti-Bacterial Agents
PubMed: 37751552
DOI: 10.1073/pnas.2307093120 -
Microbial Cell Factories Jun 2023A subject of great interest is the bioprospecting of microorganisms and their bioactive byproducts, such as pigments. Microbial pigments have various benefits, including... (Review)
Review
A subject of great interest is the bioprospecting of microorganisms and their bioactive byproducts, such as pigments. Microbial pigments have various benefits, including being safe to use due to their natural makeup, having therapeutic effects, and being produced all year round, regardless of the weather or location. Pseudomonas aeruginosa produces phenazine pigments that are crucial for interactions between Pseudomonas species and other living things. Pyocyanin pigment, which is synthesized by 90-95% of P. aeruginosa, has potent antibacterial, antioxidant, and anticancer properties. Herein, we will concentrate on the production and extraction of pyocyanin pigment and its biological use in different areas of biotechnology, engineering, and biology.
Topics: Pyocyanine; Pseudomonas aeruginosa; Pseudomonas; Anti-Bacterial Agents; Antioxidants
PubMed: 37291560
DOI: 10.1186/s12934-023-02122-1 -
Proceedings of the National Academy of... May 2022Surface sensing is a critical process that promotes the transition to a biofilm lifestyle. Several surface-sensing mechanisms have been described for a range of species,...
Surface sensing is a critical process that promotes the transition to a biofilm lifestyle. Several surface-sensing mechanisms have been described for a range of species, most involving surface appendages, such as flagella and pili. Pseudomonas aeruginosa uses the Wsp chemosensory-like signal transduction pathway to sense surfaces and promote biofilm formation. The methyl-accepting chemotaxis protein WspA recognizes an unknown surface-associated signal and initiates a phosphorylation cascade that activates the diguanylate cyclase WspR. We conducted a screen for Wsp-activating compounds and found that chemicals that impact the cell envelope induce Wsp signaling, increase intracellular c-di-GMP levels, and can promote surface attachment. To isolate the Wsp system from other P. aeruginosa surface-sensing systems, we heterologously expressed it in Escherichia coli and found it sufficient for sensing surfaces and the chemicals identified in our screen. Using well-characterized reporters for different E. coli cell envelope stress responses, we then determined that Wsp sensitivity overlapped with multiple E. coli cell envelope stress-response systems. Using mutational and CRISPRi analysis, we found that misfolded proteins in the periplasm appear to be a major stimulus of the Wsp system. Finally, we show that surface attachment appears to have an immediate, observable effect on cell envelope integrity. Collectively, our results provide experimental evidence that cell envelope stress represents an important feature of surface sensing in P. aeruginosa.
Topics: Biofilms; Cell Membrane; Cell Wall; Periplasm; Pseudomonas aeruginosa
PubMed: 35476526
DOI: 10.1073/pnas.2117633119 -
Antimicrobial Resistance and Infection... Nov 2020The distribution of β-lactam resistance genes in P. aeruginosa is often closely related to the distribution of certain high-risk international clones. We used...
BACKGROUND
The distribution of β-lactam resistance genes in P. aeruginosa is often closely related to the distribution of certain high-risk international clones. We used whole-genome sequencing (WGS) to identify the predominant sequence types (ST) and β-lactamase genes in clinical isolates of multidrug-resistant (MDR)-P. aeruginosa from Qatar METHODS: Microbiological identification and susceptibility tests were performed by automated BD Phoenix™ system and manual Liofilchem MIC Test Strips.
RESULTS
Among 75 MDR-P. aeruginosa isolates; the largest proportions of susceptibility were to ceftazidime-avibactam (n = 36, 48%), followed by ceftolozane-tazobactam (30, 40%), ceftazidime (n = 21, 28%) and aztreonam (n = 16, 21.3%). All isolates possessed Class C and/or Class D β-lactamases (n = 72, 96% each), while metallo-β-lactamases were detected in 20 (26.7%) isolates. Eight (40%) metallo-β-lactamase producers were susceptible to aztreonam and did not produce any concomitant extended-spectrum β-lactamases. High risk ST235 (n = 16, 21.3%), ST357 (n = 8, 10.7%), ST389 and ST1284 (6, 8% each) were most frequent. Nearly all ST235 isolates (15/16; 93.8%) were resistant to all tested β-lactams.
CONCLUSION
MDR-P. aeruginosa isolates from Qatar are highly resistant to antipseudomonal β-lactams. High-risk STs are predominant in Qatar and their associated MDR phenotypes are a cause for considerable concern.
Topics: Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Whole Genome Sequencing; beta-Lactamases
PubMed: 33131487
DOI: 10.1186/s13756-020-00838-y -
Molecular Plant Pathology Jan 2022Pseudomonas viridiflava is a gram-negative pseudomonad that is phylogenetically placed within the Pseudomonas syringae species complex. P. viridiflava has a wide host...
UNLABELLED
Pseudomonas viridiflava is a gram-negative pseudomonad that is phylogenetically placed within the Pseudomonas syringae species complex. P. viridiflava has a wide host range and causes a variety of symptoms in different plant parts, including stems, leaves, and blossoms. Outside of its role as a pathogen, P. viridiflava also exists as an endophyte, epiphyte, and saprophyte. Increased reports of P. viridiflava causing disease on new hosts in recent years coincide with increased research on its genetic variability, virulence, phylogenetics, and phenotypes. There is high variation in its core genome, virulence factors, and phenotypic characteristics. The main virulence factors of this pathogen include the enzyme pectate lyase and virulence genes encoded within one or two pathogenicity islands. The delineation of P. viridiflava in the P. syringae complex has been investigated using several molecular approaches. P. viridiflava comprises its own species, within the complex. While seemingly an outsider to the complex as a whole due to differences in the core genome and virulence genes, low average nucleotide identity to other of P. syringae complex members, and some phenotypic traits, it remains as part of the complex. Defining phylogenetic, phenotypic, and genomic characteristics of P. viridiflava in comparison to other P. syringae members is important to understanding this pathogen and for the development of disease resistance and management practices.
TAXONOMY
Kingdom Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Family Pseudomonadaceae; Genus Pseudomonas; Species Pseudomonas syringae species complex, Genomospecies 6, Phylogroup 7 and 8.
MICROBIOLOGICAL PROPERTIES
Gram-negative, fluorescent, aerobic, motile, rod-shaped, oxidase negative, arginine dihydrolase negative, levan production negative (or positive), potato rot positive (or negative), tobacco hypersensitivity positive.
GENOME
There are two complete genomes, five chromosome-level genomes, and 1,540 genomes composed of multiple scaffolds of P. viridiflava available in the National Center for Biotechnology Information Genome database. The median total length of these assemblies is 5,975,050 bp, the median number of protein coding genes is 5,208, and the median G + C content is 59.3%.
DISEASE SYMPTOMS
P. viridiflava causes a variety of disease symptoms, including spots, streaks, necrosis, rots, and more in above- and below-ground plant parts on at least 50 hosts.
EPIDEMIOLOGY
There have been several significant disease outbreaks on field and horticultural crops caused by P. viridiflava since the turn of the century. P. viridiflava has been reported as a pathogen, epiphyte, endophyte, and saprophyte. This species has been isolated from a variety of environmental sources, including asymptomatic wild plants, snow, epilithic biofilms, and icepacks.
Topics: Phylogeny; Plant Diseases; Pseudomonas; Pseudomonas syringae; Virulence
PubMed: 34463014
DOI: 10.1111/mpp.13133