{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T00:27:27Z","timestamp":1767832047021,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2021,8,27]],"date-time":"2021-08-27T00:00:00Z","timestamp":1630022400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/04050\/2020"],"award-info":[{"award-number":["UIDB\/04050\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["SFRH\/BD\/98558\/2013"],"award-info":[{"award-number":["SFRH\/BD\/98558\/2013"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>Pseudomonas aeruginosa can alter its lifestyle in response to changes in environmental conditions. The switch to a pathogenic host-associated lifestyle can be triggered by the luminosity settings, resorting to at least one photoreceptor which senses light and regulates cellular processes. This study aimed to address how light exposure affects the dynamic and adaptability of two P. aeruginosa pneumonia-associated isolates, HB13 and HB15. A phenotypic characterization of two opposing growth conditions, constant illumination and intensity of full-spectrum light and total absence of light, was performed. Given the nature of P. aeruginosa pathogenicity, distinct fractions were characterized, and its inherent pathogenic potential screened by comparing induced morphological alterations and cytotoxicity against human pulmonary epithelial cells (A549 cell line). Growth in the dark promoted some virulence-associated traits (e.g., pigment production, LasA proteolytic activity), which, together with higher cytotoxicity of secreted fractions, supported an increased pathogenic potential in conditions that better mimic the lung microenvironment of P. aeruginosa. These preliminary findings evidenced that light exposure settings may influence the P. aeruginosa pathogenic potential, likely owing to differential production of virulence factors. Thus, this study raised awareness towards the importance in controlling light conditions during bacterial pathogenicity evaluation approaches, to more accurately interpret bacterial responses.<\/jats:p>","DOI":"10.3390\/biology10090837","type":"journal-article","created":{"date-parts":[[2021,8,27]],"date-time":"2021-08-27T09:53:23Z","timestamp":1630058003000},"page":"837","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Absence of Light Exposure Increases Pathogenicity of Pseudomonas aeruginosa Pneumonia-Associated Clinical Isolates"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7709-8689","authenticated-orcid":false,"given":"Cristina S.","family":"Mesquita","sequence":"first","affiliation":[{"name":"CBMA\u2014Centre of Molecular and Environmental Biology, Department of Biology, Campus of Gualtar, University of Minho, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3298-5564","authenticated-orcid":false,"given":"Artur","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"CEB\u2014Centre of Biological Engineering, Campus of Gualtar, University of Minho, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0567-064X","authenticated-orcid":false,"given":"Andreia C.","family":"Gomes","sequence":"additional","affiliation":[{"name":"CBMA\u2014Centre of Molecular and Environmental Biology, Department of Biology, Campus of Gualtar, University of Minho, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3234-4265","authenticated-orcid":false,"given":"Pedro M.","family":"Santos","sequence":"additional","affiliation":[{"name":"CBMA\u2014Centre of Molecular and Environmental Biology, Department of Biology, Campus of Gualtar, University of Minho, 4710-057 Braga, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1093\/jac\/dkp201","article-title":"Update on the treatment of Pseudomonas aeruginosa pneumonia","volume":"64","author":"Alhajhusain","year":"2009","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1209","DOI":"10.1164\/rccm.200408-1044SO","article-title":"Pathogen-host interactions in Pseudomonas aeruginosa pneumonia","volume":"171","author":"Sadikot","year":"2005","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1111\/2049-632X.12033","article-title":"Pseudomonas aeruginosa: New insights into pathogenesis and host defenses","volume":"67","author":"Gellatly","year":"2013","journal-title":"Pathog. Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"R90","DOI":"10.1186\/gb-2006-7-10-r90","article-title":"Genomic analysis reveals that Pseudomonas aeruginosa virulence is combinatorial","volume":"7","author":"Lee","year":"2006","journal-title":"Genome Biol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"7512","DOI":"10.4049\/jimmunol.175.11.7512","article-title":"The exopolysaccharide alginate protects Pseudomonas aeruginosa biofilm bacteria from IFN-gamma-mediated macrophage killing","volume":"175","author":"Leid","year":"2005","journal-title":"J. Immunol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1049","DOI":"10.1046\/j.1432-1327.2001.01967.x","article-title":"Hydrolysis of glycine-containing elastin pentapeptides by LasA, a metalloelastase from Pseudomonas aeruginosa","volume":"268","author":"Vessillier","year":"2001","journal-title":"Eur. J. Biochem."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"8815","DOI":"10.1073\/pnas.97.16.8815","article-title":"Plants and animals share functionally common bacterial virulence factors","volume":"97","author":"Rahme","year":"2000","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1821","DOI":"10.1073\/pnas.1424954112","article-title":"Mitophagy confers resistance to siderophore-mediated killing by Pseudomonas aeruginosa","volume":"112","author":"Kirienko","year":"2015","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.3389\/fmicb.2017.01053","article-title":"Outer Membrane Vesicles (OMVs) of gram-negative bacteria: A perspective update","volume":"8","author":"Jan","year":"2017","journal-title":"Front. Microbiol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fcimb.2017.00039","article-title":"Pseudomonas aeruginosa lifestyle: A paradigm for adaptation, survival, and persistence","volume":"7","author":"Moradali","year":"2017","journal-title":"Front. Cell. Infect. Microbiol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1016\/j.tim.2011.05.002","article-title":"Light helps bacteria make important lifestyle decisions","volume":"19","author":"Gomelsky","year":"2011","journal-title":"Trends Microbiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"14715","DOI":"10.1073\/pnas.0806718105","article-title":"Crystal structure of Pseudomonas aeruginosa bacteriophytochrome: Photoconversion and signal transduction","volume":"105","author":"Yang","year":"2008","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"554","DOI":"10.1016\/j.tim.2007.09.009","article-title":"Photosensing in chemotrophic, non-phototrophic bacteria: Let there be light sensing too","volume":"15","author":"Key","year":"2007","journal-title":"Trends Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Mukherjee, S., Jemielita, M., Stergioula, V., Tikhonov, M., and Bassler, B.L. (2019). Photosensing and quorum sensing are integrated to control Pseudomonas aeruginosa collective behaviors. PLoS Biol., 17.","DOI":"10.1101\/747618"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"e00117","DOI":"10.1128\/JB.00117-20","article-title":"Light-mediated decreases in cyclic di-GMP levels inhibit structure formation in Pseudomonas aeruginosa biofilms","volume":"202","author":"Kahl","year":"2020","journal-title":"J. Bacteriol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"959","DOI":"10.1038\/35023079","article-title":"Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen","volume":"406","author":"Stover","year":"2000","journal-title":"Nature"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"103702","DOI":"10.1016\/j.micpath.2019.103702","article-title":"Identification of genomic loci associated with genotypic and phenotypic variation among Pseudomonas aeruginosa clinical isolates from pneumonia","volume":"136","author":"Mesquita","year":"2019","journal-title":"Microb. Pathog."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1417","DOI":"10.1093\/jnci\/51.5.1417","article-title":"In vitro cultivation of human tumors: Establishment of cell lines derived from a series of solid tumors","volume":"51","author":"Giard","year":"1973","journal-title":"J. Natl. Cancer Inst."},{"key":"ref_19","unstructured":"Clinical and Laboratory Standards Institute (CLSI) (2021). Performance Standards for Antimicrobial Susceptibility Testing (M100\u2013ED31), Clinical and Laboratory Standards Institute (CLSI)."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1038\/nprot.2007.521","article-title":"Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances","volume":"3","author":"Wiegand","year":"2008","journal-title":"Nat. Protoc."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1128\/JB.00797-08","article-title":"Interaction between bacteriophage DMS3 and host CRISPR region inhibits group behaviors of Pseudomonas aeruginosa","volume":"191","author":"Zegans","year":"2009","journal-title":"J. Bacteriol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"4908","DOI":"10.1128\/JB.187.14.4908-4920.2005","article-title":"A cystic fibrosis epidemic strain of Pseudomonas aeruginosa displays enhanced virulence and antimicrobial resistance","volume":"187","author":"Salunkhe","year":"2005","journal-title":"J. Bacteriol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"971","DOI":"10.1016\/j.chembiol.2004.04.014","article-title":"Characterization and genetic manipulation of peptide synthetases in Pseudomonas aeruginosa PAO1 in order to generate novel pyoverdines","volume":"11","author":"Ackerley","year":"2004","journal-title":"Chem. Biol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/0003-2697(79)90222-7","article-title":"Review of the folin phenol protein quantitation method of lowry, rosebrough, farr and randall","volume":"100","author":"Peterson","year":"1979","journal-title":"Anal. Biochem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"24866","DOI":"10.1038\/srep24866","article-title":"Protecting enzymatic function through directed packaging into bacterial outer membrane vesicles","volume":"6","author":"Alves","year":"2016","journal-title":"Sci. Rep."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"554","DOI":"10.1525\/abt.2011.73.9.9","article-title":"A quick & automated method for measuring cell area using ImageJ","volume":"73","author":"Baviskar","year":"2011","journal-title":"Am. Biol. Teach."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"9499","DOI":"10.1007\/s00253-016-7668-4","article-title":"Albumin\/asparaginase capsules prepared by ultrasound to retain ammonia","volume":"100","author":"Tinoco","year":"2016","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Toska, J., Sun, Y., Carbonell, D.A., Foster, A.N.S., Jacobs, M.R., Pearlman, E., and Rietsch, A. (2014). Diversity of virulence phenotypes among type III secretion negative Pseudomonas aeruginosa clinical isolates. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0086829"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1146\/annurev.cellbio.18.012502.134748","article-title":"Bacterial toxins that modify the actin cytoskeleton","volume":"18","author":"Barbieri","year":"2002","journal-title":"Annu. Rev. Cell Dev. Biol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1111\/1751-7915.12144","article-title":"Apoptosis induced by Pseudomonas aeruginosa: A lonely killer?","volume":"8","author":"Broquet","year":"2015","journal-title":"Microb. Biotechnol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1038\/s41580-018-0080-4","article-title":"New insights into the mechanisms of epithelial\u2013mesenchymal transition and implications for cancer","volume":"20","author":"Dongre","year":"2019","journal-title":"Nat. Rev. Mol. Cell Biol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1237","DOI":"10.1183\/09031936.00088410","article-title":"Pseudomonas aeruginosa accentuates epithelial-to-mesenchymal transition in the airway","volume":"37","author":"Borthwick","year":"2011","journal-title":"Eur. Respir. J."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1002\/lsm.20948","article-title":"Visible light-induced killing of bacteria as a function of wavelength: Implication for wound healing","volume":"42","author":"Lipovsky","year":"2010","journal-title":"Lasers Surg. Med."}],"container-title":["Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-7737\/10\/9\/837\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:53:52Z","timestamp":1760165632000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-7737\/10\/9\/837"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,27]]},"references-count":33,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2021,9]]}},"alternative-id":["biology10090837"],"URL":"https:\/\/doi.org\/10.3390\/biology10090837","relation":{},"ISSN":["2079-7737"],"issn-type":[{"value":"2079-7737","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,27]]}}}