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2. Characterization of bacterial communities associated with seabed sediments in offshore and nearshore sites to improve Microbiologically Influenced Corrosion mitigation on marine infrastructures.

Author

Ghezzi, Daniele, Mangiaterra, Gianmarco, Scardino, Arianna, Fehervari, Mauro, Magnani, Mauro, Citterio, Barbara, and Frangipani, Emanuela

Subjects
MICROBIOLOGICALLY influenced corrosion, MARINE sediments, ANTHROPOGENIC effects on nature, STRUCTURAL failures, INFRASTRUCTURE (Economics)
Abstract

Microbiologically Influenced Corrosion (MIC) is one of the main threats for marine infrastructures, leading to severe safety and environmental risks associated with structural failures and/or leakages of dangerous fluids, together with potential huge economic losses and reputational damage for the involved parts. For a safe design and a proper installation of infrastructure systems in contact with the seabed, a deep knowledge of the site-specific microbial community of the sediments should be beneficial. Therefore, in addition to the simple detection or the sole quantification of Sulphate-Reducing Bacteria (SRB), the whole characterization of the microbial members involved in MIC phenomena is desirable. In this study, 16S rRNA-based comparison between bacterial communities thriving in offshore and nearshore marine sediments was performed, with a focus on the main bacterial groups putatively responsible for MIC. The nearshore sediments were significantly enriched in bacterial members associated with human and organic compounds contamination belonging to the Bacteroidota, Desulfobacterota, and Firmicutes phyla, while the offshore sediments hosted Alphaproteobacteria, Nitrospinota, and Nitrospirota members, representative of a low anthropogenic impact. Quantitative PCR targeting the dsrA gene and detailed community analyses revealed that the nearshore sediments were significantly enriched in SRB mainly affiliated to the Desulfobulbus and Desulfosarcina genera potentially involved in biocorrosion, compared to the offshore ones. These results suggest that the bacterial community associated with the high concentration of organic compounds derived by an elevated anthropogenic impact is likely to favour MIC. Such observations highlight the importance of microbiological investigations as prevention strategy against MIC processes, aiming both at characterizing sites for the establishment of new infrastructures and at monitoring those already installed. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Alkyl-quinolone-dependent quorum sensing controls prophage-mediated autolysis in Pseudomonas aeruginosa colony biofilms

Author

Giallonardi, Giulia, primary, Letizia, Morgana, additional, Mellini, Marta, additional, Frangipani, Emanuela, additional, Halliday, Nigel, additional, Heeb, Stephan, additional, Cámara, Miguel, additional, Visca, Paolo, additional, Imperi, Francesco, additional, Leoni, Livia, additional, Williams, Paul, additional, and Rampioni, Giordano, additional

Published
2023
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11. Class 1 integron and Enterococcus spp. abundances in swine farms from the “ Suckling piglets” to the “Fatteners” production category

Author

Di Cesare, Andrea, primary, Frangipani, Emanuela, additional, Citterio, Barbara, additional, Sabatino, Raffaella, additional, Corno, Gianluca, additional, Fontaneto, Diego, additional, Mangiaterra, Gianmarco, additional, Bencardino, Daniela, additional, Zoppi, Simona, additional, Di Blasio, Alessia, additional, Desiato, Rosanna, additional, Ru, Giuseppe, additional, and Marchis, Daniela, additional

Published
2022
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15. Structural Biology of Bacterial Haemophores

Author

Ascenzi, Paolo, primary, di Masi, Alessandra, additional, Leboffe, Loris, additional, Frangipani, Emanuela, additional, Nardini, Marco, additional, Verde, Cinzia, additional, and Visca, Paolo, additional

Published
2015
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16. Berberine Derivatives as Pseudomonas aeruginosa MexXY-OprM Inhibitors: Activity and In Silico Insights

Author

Giorgini, Giorgia, primary, Mangiaterra, Gianmarco, additional, Cedraro, Nicholas, additional, Laudadio, Emiliano, additional, Sabbatini, Giulia, additional, Cantarini, Mattia, additional, Minnelli, Cristina, additional, Mobbili, Giovanna, additional, Frangipani, Emanuela, additional, Biavasco, Francesca, additional, and Galeazzi, Roberta, additional

Published
2021
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19. Intra-tracheal administration increases gallium availability in lung: implications for antibacterial chemotherapy

Author

Mitidieri, Emma, primary, Visaggio, Daniela, additional, Frangipani, Emanuela, additional, Turnaturi, Carlotta, additional, Vanacore, Domenico, additional, Provenzano, Romina, additional, Costabile, Gabriella, additional, Sorrentino, Raffaella, additional, Ungaro, Francesca, additional, Visca, Paolo, additional, and d’Emmanuele di Villa Bianca, Roberta, additional

Published
2021
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27. Adaptation of aerobically growing Pseudomonas aeruginosa to copper starvation

Author

Frangipani, Emanuela, Slaveykova, Vera I., Reimmann, Cornelia, and Haas, Dieter

Subjects
Pseudomonas aeruginosa -- Physiological aspects, Pseudomonas aeruginosa -- Genetic aspects, Oxidases -- Physiological aspects, Oxidases -- Research, Microbial respiration -- Physiological aspects, Microbial respiration -- Research, Biological sciences
Abstract

Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogen Pseudomonas aeruginosa to copper limitation was assessed under aerobic conditions. Expression of cioAB (encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions (including the siderophores pyoverdine and pyochelin) were expressed at reduced levels, presumably reflecting a lower demand for iron by respiratory enzymes. Wild-type P. aeruginosa was able to grow aerobically in a defined glucose medium depleted of copper, whereas a cioAB mutant did not grow. Thus, P. aeruginosa relies on the CioAB enzyme to cope with severe copper deprivation. A quadruple cyo cco1 cco2 cox mutant, which was deleted for all known heme-copper terminal oxidases of P. aeruginosa, grew aerobically, albeit more slowly than did the wild type, indicating that the CioAB enzyme is capable of energy conservation. However, the expression of a cioA'-'lacZ fusion was less dependent on the copper status in the quadruple mutant than in the wild type, suggesting that copper availability might affect cioAB expression indirectly, via the function of the heme-copper oxidases.

Published
2008

28. Involvement of Pseudomonas aeruginosa rhodanese in protection from cyanide toxicity

Author

Cipollone, Rita, Frangipani, Emanuela, Tiburzi, Federica, Imperi, Francesco, Ascenzi, Paolo, and Visca, Paolo

Subjects
Pseudomonas aeruginosa -- Genetic aspects, Pseudomonas aeruginosa -- Research, Cyanides -- Chemical properties, Microbial respiration -- Research, Biological sciences
Abstract

The presence of multiple sulfurtransferases in the cyanogenic bacterium Pseudomonas aeruginosa PAO1 is described and RhdA, a thiosulfate:cyanide sulfutransferase (rhodanese), which converts cyanide to less toxic thiocyanate, is examined. RhdA is regarded as an effector of Pseudomonas aeruginosa intrinsic resistance to cyanide, as it provides the bacterium with a defense mechanism against endogenous cyanide toxin, in addition to cyanide-resistant respiration.

Published
2007

37. Contribution of Active Iron Uptake to Acinetobacter baumannii Pathogenicity

Author

Runci, Federica, primary, Gentile, Valentina, additional, Frangipani, Emanuela, additional, Rampioni, Giordano, additional, Leoni, Livia, additional, Lucidi, Massimiliano, additional, Visaggio, Daniela, additional, Harris, Greg, additional, Chen, Wangxue, additional, Stahl, Julia, additional, Averhoff, Beate, additional, and Visca, Paolo, additional

Published
2019
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38. Gallium- and Iron-Pyoverdine Coordination Compounds Investigated by X-ray Photoelectron Spectroscopy and X-ray Absorption Spectroscopy

Author

Nicolafrancesco, Chiara, primary, Porcaro, Francesco, additional, Pis, Igor, additional, Nappini, Silvia, additional, Simonelli, Laura, additional, Marini, Carlo, additional, Frangipani, Emanuela, additional, Visaggio, Daniela, additional, Visca, Paolo, additional, Mobilio, Settimio, additional, Meneghini, Carlo, additional, Fratoddi, Ilaria, additional, Iucci, Giovanna, additional, and Battocchio, Chiara, additional

Published
2019
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39. Identification of a Pseudomonas aeruginosa PAO1 DNA methyltransferase, its Targets, and physiological roles

Author

Doberenz, Sebastian, Eckweiler, Denitsa, Reichert, Olga, Jensen, Vanessa, Bunk, Boyke, Kordes, Adrian, Frangipani, Emanuela, Luong, Khai, Korlach, Jonas, Heeb, Stephan, and Kaever, Volkhard

Abstract

DNA methylation is widespread among prokaryotes, and most DNA methylation reactions are catalyzed by adenine DNA methyltransferases, which are part of restriction-modification (R-M) systems. R-M systems are known for their role in the defense against foreign DNA; however, DNA methyltransferases also play functional roles in gene regulation. In this study, we used single-molecule real-time (SMRT) sequencing to uncover the genome-wide DNA methylation pattern in the opportunistic pathogen Pseudomonas aeruginosa PAO1. We identified a conserved sequence motif targeted by an adenine methyltransferase of a type I R-M system and quantified the presence of N(6)-methyladenine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Changes in the PAO1 methylation status were dependent on growth conditions and affected P. aeruginosa pathogenicity in a Galleria mellonella infection model. Furthermore, we found that methylated motifs in promoter regions led to shifts in sense and antisense gene expression, emphasizing the role of enzymatic DNA methylation as an epigenetic control of phenotypic traits in P. aeruginosa Since the DNA methylation enzymes are not encoded in the core genome, our findings illustrate how the acquisition of accessory genes can shape the global P. aeruginosa transcriptome and thus may facilitate adaptation to new and challenging habitats.IMPORTANCE With the introduction of advanced technologies, epigenetic regulation by DNA methyltransferases in bacteria has become a subject of intense studies. Here we identified an adenosine DNA methyltransferase in the opportunistic pathogen Pseudomonas aeruginosa PAO1, which is responsible for DNA methylation of a conserved sequence motif. The methylation level of all target sequences throughout the PAO1 genome was approximated to be in the range of 65 to 85% and was dependent on growth conditions. Inactivation of the methyltransferase revealed an attenuated-virulence phenotype in the Galleria mellonella infection model. Furthermore, differential expression of more than 90 genes was detected, including the small regulatory RNA prrF1, which contributes to a global iron-sparing response via the repression of a set of gene targets. Our finding of a methylation-dependent repression of the antisense transcript of the prrF1 small regulatory RNA significantly expands our understanding of the regulatory mechanisms underlying active DNA methylation in bacteria.

Published
2017

40. Structural Biology of Bacterial Haemophores

Author

Ascenzi, Paolo, DI MASI, Alessandra, Leboffe, Loris, Frangipani, Emanuela, Nardini, Marco, Verde, Cinzia, Visca, Paolo, Ascenzi, Paolo, DI MASI, Alessandra, Leboffe, Lori, Frangipani, Emanuela, Nardini, Marco, Verde, Cinzia, and Visca, Paolo

Subjects
Haem acquisition, Physiology, digestive, oral, and skin physiology, polycyclic compounds, Structure-function relationship, Bacterial haemophores, Haem degradation, Haem internalization, Structure-function relationships, Microbiology, Bacterial haemophore
Abstract

Iron plays a key role in a wide range of metabolic and signalling functions representing an essential nutrient for almost all forms of life. However, the ferric form is hardly soluble, whereas the ferrous form is highly toxic. Thus, in biological fluids, most of the iron is sequestered in iron- or haem-binding proteins and the level of free iron is low, making haem and iron acquisition a challenge for pathogenic bacteria during infections. Although toxic to the host, free haem is a major and readily available source of iron for several pathogenic microorganisms. Both Gram-positive and Gram-negative bacteria have developed several strategies to acquire free haem-Fe and protein-bound haem-Fe. Haemophores are a class of secreted and cell surface-exposed proteins promoting free-haem uptake, haem extraction from host haem proteins, and haem presentation to specific outer-membrane receptors that internalize the metal-porphyrins. Here, structural biology of bacterial haemophores is reviewed focusing on haem acquisition, haem internalization, and haem-degrading systems.

Published
2015

44. Copper acquisition by the SenC protein regulates aerobic respiration in Pseudomonas aeruginosa PAO1

Author

Frangipani, Emanuela, Haas, Dieter, Frangipani, Emanuela, and Haas, Dieter

Abstract

Aerobic respiration of Pseudomonas aeruginosa involves four terminal oxidases belonging to the heme-copper family (that is, three cytochrome c oxidases and one quinol oxidase) plus one copper-independent, cyanide-insensitive quinol oxidase (CIO). The PA0114 gene encoding an SCO1/SenC-type protein, which is known to be important for copper delivery to cytochrome c in yeast, Rhodobacter spp. and Agrobacterium tumefaciens, was found to be important for copper acquisition and aerobic respiration in P. aeruginosa. A PA0114 (senC) mutant grew poorly in low-copper media and had low cytochrome cbb3-type oxidase activity, but expressed CIO at increased levels, by comparison with the wild-type PAO1. Addition of copper reversed these phenotypes, suggesting that periplasmic copper capture by the SenC protein helps P. aeruginosa to adapt to copper deprivation

Published
2017

45. Unravelling the Genome-Wide Contributions of Specific 2-Alkyl-4-Quinolones and PqsE to Quorum Sensing in Pseudomonas aeruginosa

Author

Rampioni, Giordano, Falcone, Marilena, Heeb, Stephan, Frangipani, Emanuela, Fletcher, Matthew P., Visca, Paolo, Leoni, Levi, Williams, Paul, and Pesci, Everett

Abstract

The pqs quorum sensing (QS) system is crucial for Pseudomonas aeruginosa virulence both in vitro and in animal models of infection and is considered an ideal target for the development of anti-virulence agents. However, the precise role played by each individual component of this complex QS circuit in the control of virulence remains to be elucidated. Key components of the pqs QS system are 2-heptyl-4-hydroxyquinoline (HHQ), 2-heptyl-3-hydroxy-4-quinolone (PQS), 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), the transcriptional regulator PqsR and the PQS-effector element PqsE. To define the individual contribution of each of these components to QS-mediated regulation, transcriptomic analyses were performed and validated on engineered P. aeruginosa strains in which the biosynthesis of 2-alkyl 4-quinolones (AQs) and expression of pqsE and pqsR have been uncoupled, facilitating the identification of the genes controlled by individual pqs system components. The results obtained demonstrate that i) the PQS biosynthetic precursor HHQ triggers a PqsR-dependent positive feedback loop that leads to the increased expression of only the pqsABCDE operon, ii) PqsE is involved in the regulation of diverse genes coding for key virulence determinants and biofilm development, iii) PQS promotes AQ biosynthesis, the expression of genes involved in the iron-starvation response and virulence factor production via PqsR-dependent and PqsR-independent pathways, and iv) HQNO does not influence transcription and hence does not function as a QS signal molecule. Overall this work has facilitated identification of the specific regulons controlled by individual pqs system components and uncovered the ability of PQS to contribute to gene regulation independent of both its ability to activate PqsR and to induce the iron-starvation response.

Published
2016

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