1
|
Maršík D, Danda M, Otta J, Thoresen PP, Mat́átková O, Rova U, Christakopoulos P, Matsakas L, Masák J. Preparation and Biological Activity of Lignin-Silver Hybrid Nanoparticles. ACS OMEGA 2024; 9:47765-47787. [PMID: 39651097 PMCID: PMC11618447 DOI: 10.1021/acsomega.4c08117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2024] [Revised: 11/01/2024] [Accepted: 11/07/2024] [Indexed: 12/11/2024]
Abstract
Silver nanoparticles (AgNPs) are excellent antimicrobial agents and promising candidates for preventing or treating bacterial infections caused by antibiotic resistant strains. However, their increasing use in commercial products raises concerns about their environmental impact. In addition, traditional physicochemical approaches often involve harmful agents and excessive energy consumption, resulting in AgNPs with short-term colloidal stability and silver ion leaching. To address these issues, we designed stable hybrid lignin-silver nanoparticles (AgLigNPs) intended to effectively hit bacterial envelopes as a main antimicrobial target. The lignin nanoparticles (LigNPs), serving as a reducing and stabilizing agent for AgNPs, have a median size of 256 nm and a circularity of 0.985. These LigNPs were prepared using the dialysis solvent exchange method, producing spherical particles stable under alkaline conditions and featuring reducing groups oriented toward a wrinkled surface, facilitating AgNPs synthesis and attachment. Maximum accumulation of silver on the LigNP surface was observed at a mass reaction ratio mAg:mLig of 0.25, at pH 11. The AgLigNPs completely inhibited suspension growth and reduced biofilm development by 50% in three tested strains of Pseudomonas aeruginosa at a concentration of 80/9.5 (lignin/silver) mg L-1. Compared to unattached AgNPs, AgLigNPs required two to eight times lower silver concentrations to achieve complete inhibition. Additionally, our silver-containing nanosystems were effective against bacteria at safe concentrations in HEK-293 and HaCaT tissue cultures. Stability experiments revealed that the nanosystems tend to aggregate in media used for bacterial cell cultures but remain stable in media used for tissue cultures. In all tested media, the nanoparticles retained their integrity, and the presence of lignin facilitated the prevention of silver ions from leaching. Overall, our data demonstrate the suitability of AgLigNPs for further valorization in the biomedical sector.
Collapse
Affiliation(s)
- Dominik Maršík
- Department
of Biotechnology, University of Chemistry
and Technology, Prague 166 28, Czech Republic
| | - Matěj Danda
- Department
of Biotechnology, University of Chemistry
and Technology, Prague 166 28, Czech Republic
| | - Jaroslav Otta
- Department
of Physics and Measurements, University
of Chemistry and Technology, Prague 166 28, Czech Republic
| | - Petter P. Thoresen
- Biochemical
Process Engineering, Division of Chemical Engineering, Department
of Civil, Environmental, and Natural Resources, Luleå University of Technology, Luleå 971 87, Sweden
| | - Olga Mat́átková
- Department
of Biotechnology, University of Chemistry
and Technology, Prague 166 28, Czech Republic
| | - Ulrika Rova
- Biochemical
Process Engineering, Division of Chemical Engineering, Department
of Civil, Environmental, and Natural Resources, Luleå University of Technology, Luleå 971 87, Sweden
| | - Paul Christakopoulos
- Biochemical
Process Engineering, Division of Chemical Engineering, Department
of Civil, Environmental, and Natural Resources, Luleå University of Technology, Luleå 971 87, Sweden
| | - Leonidas Matsakas
- Biochemical
Process Engineering, Division of Chemical Engineering, Department
of Civil, Environmental, and Natural Resources, Luleå University of Technology, Luleå 971 87, Sweden
| | - Jan Masák
- Department
of Biotechnology, University of Chemistry
and Technology, Prague 166 28, Czech Republic
| |
Collapse
|
2
|
Ricardi MM, Tribelli PM, Costa CS, Pezzoni M. Global transcriptional response of Pseudomonas aeruginosa to UVA radiation. Photochem Photobiol Sci 2024; 23:2029-2044. [PMID: 39470974 DOI: 10.1007/s43630-024-00649-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 10/04/2024] [Indexed: 11/01/2024]
Abstract
Ultraviolet A (UVA) radiation is the major fraction of UV radiation reaching the Earth's surface. Its harmful effects on microorganisms, due mainly to oxidative damage, have been exploited for development of natural solar and commercial UVA-based disinfection methods. In this work, the global transcriptional response of Pseudomonas aeruginosa exposed to ultraviolet A (UVA) radiation was analyzed. To conduct this study, we analyzed the whole transcriptome of the PAO1 strain grown to logarithmic phase under sublethal doses of UVA or in the dark. We found that a total of 298 genes responded to UVA with a change of at least two-fold (5.36% of the total P. aeruginosa genome), and showed equal amount of induced and repressed genes. An important fraction of the induced genes were involved in the response to DNA damage and included induction of SOS, prophage and pyocins genes. The results presented in this study suggest that one of the main UVA targets are proteins carrying [Fe-S] clusters since several genes involved in the processes of synthesis, trafficking and assembly of these structures were upregulated. The management of intracellular iron levels also seems to be a robust response to this stress factor. The strong induction of genes involved in denitrification suggest that this pathway and/or reactive nitrogen species such as nitric oxide could have a role in the response to this radiation. Regarding the down-regulated genes, we found many involved in the biosynthesis of PQS, a quorum-sensing signal molecule with a possible role as endogenous photosensitizer.
Collapse
Affiliation(s)
- Martiniano M Ricardi
- IFIByNE (CONICET), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula M Tribelli
- IQUIBICEN (CONICET), Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cristina S Costa
- Departamento de Radiobiología, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499B1650KNA, General San Martín, Prov. de Buenos Aires, Argentina
| | - Magdalena Pezzoni
- Departamento de Radiobiología, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499B1650KNA, General San Martín, Prov. de Buenos Aires, Argentina.
| |
Collapse
|
3
|
Qaralleh H. Chemical Composition and Quorum Sensing Inhibitory Effect of Nepeta curviflora Methanolic Extract against ESBL Pseudomonas aeruginosa. J Pharmacopuncture 2023; 26:307-318. [PMID: 38162474 PMCID: PMC10739471 DOI: 10.3831/kpi.2023.26.4.307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/23/2023] [Accepted: 11/20/2023] [Indexed: 01/03/2024] Open
Abstract
Objectives Bacterial biofilm is regarded as a significant threat to the production of safe food and the arise of antibiotic-resistant bacteria. The objective of this investigation is to evaluate the quorum sensing inhibitory effect of Nepeta curviflora methanolic extract. Methods The effectiveness of the leaves at sub-inhibitory concentrations of 2.5, 1.25, and 0.6 mg/mL on the virulence factors and biofilm formation of P. aeruginosa was evaluated. The effect of N. curviflora methanolic extract on the virulence factors of P. aeruginosa, including pyocyanin, rhamnolipid, protease, and chitinase, was evaluated. Other tests including the crystal violet assay, scanning electron microscopy (SEM), swarming motility, aggregation ability, hydrophobicity and exopolysaccharide production were conducted to assess the effect of the extract on the formation of biofilm. Insight into the mode of anti-quorum sensing action was evaluated by examining the effect of the extract on the activity of N-Acyl homoserine lactone (AHL) and the expression of pslA and pelA genes. Results The results showed a significant attenuation in the production of pyocyanin and rhamnolipid and in the activities of protease and chitinase enzymes at 2.5 and 1.25 mg/mL. In addition, N. curviflora methanolic extract significantly inhibited the formation of P. aeruginosa biofilm by decreasing aggregation, hydrophobicity, and swarming motility as well as the production of exopolysaccharide (EPS). A significant reduction in AHL secretion and pslA gene expression was observed, indicating that the extract inhibited quorum sensing by disrupting the quorum-sensing systems. The quorum-sensing inhibitory effect of N. curviflora extract appears to be attributed to the presence of kaempferol, quercetin, salicylic acid, rutin, and rosmarinic acid, as indicated by LCMS analysis. Conclusion The results of the present study provide insight into the potential of developing anti-quorum sensing agents using the extract and the identified compounds to treat infections resulting from quorum sensing-mediated bacterial pathogenesis.
Collapse
Affiliation(s)
- Haitham Qaralleh
- Department of Medical Laboratory Sciences, Faculty of Allied Medical Sciences, Mutah University, Mutah, Karak, Jordan
| |
Collapse
|
4
|
Arana N, Perez Mora B, Permingeat V, Giordano R, Calderone M, Tuttobene M, Klinke S, Rinaldi J, Müller G, Mussi MA. Light regulation in critical human pathogens of clinical relevance such as Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa. Photochem Photobiol Sci 2023; 22:2019-2036. [PMID: 37269546 DOI: 10.1007/s43630-023-00437-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/08/2023] [Indexed: 06/05/2023]
Abstract
It is now clearly recognized that light modulates the physiology of many bacterial chemotrophs, either directly or indirectly. An interesting case are bacterial pathogens of clinical relevance. This work summarizes, discusses, and provides novel complementary information to what is currently known about light sensing and responses in critical human pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus. These pathogens are associated with severe hospital and community infections difficult to treat due to resistance to multiple drugs. Moreover, light responses in Brucella abortus, an important animal and human pathogen, are also compiled. Evidence recovered so far indicates that light modulates aspects related to pathogenesis, persistence, and antibiotic susceptibility in these pathogens; such as motility, biofilm formation, iron uptake, tolerance to antibiotics, hemolysis and virulence. The pathogens elicit differential responses to light depending likely on their pathophysiology, ability to cause disease and characteristics of the host. The response to light is not restricted to discrete physiological traits but is global. In higher organisms, light provides spatial and temporal information. Then, it is crucial to understand what information light is providing in these bacterial pathogens. Our current hypothesis postulates that light serves as a signal that allows these pathogens to synchronize their behavior to the circadian rhythm of the host, to optimize infection. Advances on the molecular mechanism of light signal transduction and physiological responses to light, as well as in the relation between light and bacterial infection, would not only enlarge our understanding of bacterial pathogenesis but also could potentially provide alternative treatment options for infectious illnesses.
Collapse
Affiliation(s)
- Natalia Arana
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Bárbara Perez Mora
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Valentín Permingeat
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Rocío Giordano
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Malena Calderone
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Marisel Tuttobene
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Rosario, Argentina
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, (C1405BWE) Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Jimena Rinaldi
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, (C1405BWE) Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Gabriela Müller
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina.
| | - María Alejandra Mussi
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Argentina.
| |
Collapse
|
5
|
Condinho M, Carvalho B, Cruz A, Pinto SN, Arraiano CM, Pobre V. The role of RNA regulators, quorum sensing and c-di-GMP in bacterial biofilm formation. FEBS Open Bio 2023; 13:975-991. [PMID: 35234364 PMCID: PMC10240345 DOI: 10.1002/2211-5463.13389] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/15/2022] [Accepted: 02/28/2022] [Indexed: 11/10/2022] Open
Abstract
Biofilms provide an ecological advantage against many environmental stressors, such as pH and temperature, making it the most common life-cycle stage for many bacteria. These protective characteristics make eradication of bacterial biofilms challenging. This is especially true in the health sector where biofilm formation on hospital or patient equipment, such as respirators, or catheters, can quickly become a source of anti-microbial resistant strains. Biofilms are complex structures encased in a self-produced polymeric matrix containing numerous components such as polysaccharides, proteins, signalling molecules, extracellular DNA and extracellular RNA. Biofilm formation is tightly controlled by several regulators, including quorum sensing (QS), cyclic diguanylate (c-di-GMP) and small non-coding RNAs (sRNAs). These three regulators in particular are fundamental in all stages of biofilm formation; in addition, their pathways overlap, and the significance of their role is strain-dependent. Currently, ribonucleases are also of interest for their potential role as biofilm regulators, and their relationships with QS, c-di-GMP and sRNAs have been investigated. This review article will focus on these four biofilm regulators (ribonucleases, QS, c-di-GMP and sRNAs) and the relationships between them.
Collapse
Affiliation(s)
- Manuel Condinho
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Beatriz Carvalho
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Adriana Cruz
- iBB‐Institute for Bioengineering and Biosciences (IBB)Instituto Superior TécnicoLisboaPortugal
- i4HB‐Institute for Health and BioeconomyInstituto Superior TécnicoLisboaPortugal
| | - Sandra N. Pinto
- iBB‐Institute for Bioengineering and Biosciences (IBB)Instituto Superior TécnicoLisboaPortugal
- i4HB‐Institute for Health and BioeconomyInstituto Superior TécnicoLisboaPortugal
| | - Cecília M. Arraiano
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| | - Vânia Pobre
- Instituto de Tecnologia Química e Biológica António XavierUniversidade Nova de LisboaOeirasPortugal
| |
Collapse
|
6
|
Grossich R, Lemos Vilches M, Costa CS, Pezzoni M. Role of Pel and Psl polysaccharides in the response of Pseudomonas aeruginosa to environmental challenges: oxidative stress agents (UVA, H 2O 2, sodium hypochlorite) and its competitor Staphylococcus aureus. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36757866 DOI: 10.1099/mic.0.001301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Pseudomonas aeruginosa is a versatile bacterium capable of adapting to a wide range of stress factors, including solar UVA radiation (400-315 nm). High UVA doses produce lethal effects due to the action of reactive oxygen species. Sublethal UVA doses also induces oxidative damage, but, in addition, it triggers a variety of adaptive responses, including the overexpression of pelA and pslA genes in P. aeruginosa. These genes encode the synthesis of Pel and Psl, which are essential polysaccharides in biofilm formation. The present study analysed the role of Pel and Psl in the adaptive responses generated by exposure to low UVA doses, and their importance in the response to lethal doses of UVA, hydrogen peroxide (H2O2), and sodium hypochlorite, in both planktonic cells and submerged and air-liquid interface (ALI) biofilms. It also studied the roles of Pel and Psl in P. aeruginosa-Staphylococcus aureus interaction. The results demonstrate that the capacity of sublethal UVA exposure to increase cell hydrophobicity and cell attachment and generate cross-protection phenomena in P. aeruginosa depends on the presence of Pel and Psl. The study also shows that Pel and Psl have a key role in the tolerance to lethal doses of UVA radiation, sodium hypochlorite and H2O2, in both biofilms and planktonic cells. Finally, co-culture assays showed total inhibition of S. aureus growth in presence of P. aeruginosa. This phenomenon depends, at least in part, on the simultaneous presence of Pel and Psl in planktonic cells and biofilms, suggesting a relevant role of these polysaccharides in the interaction between these species.
Collapse
Affiliation(s)
- Romina Grossich
- Departamento de Radiobiología, Comision Nacional de Energía Atómica, San Martín, Buenos Aires, Argentina
| | - Martín Lemos Vilches
- Departamento de Radiobiología, Comision Nacional de Energía Atómica, San Martín, Buenos Aires, Argentina
| | - Cristina S Costa
- Departamento de Radiobiología, Comision Nacional de Energía Atómica, San Martín, Buenos Aires, Argentina
| | - Magdalena Pezzoni
- Departamento de Radiobiología, Comision Nacional de Energía Atómica, San Martín, Buenos Aires, Argentina
| |
Collapse
|
7
|
UVA as environmental signal for alginate production in Pseudomonas aeruginosa: role of this polysaccharide in the protection of planktonic cells and biofilms against lethal UVA doses. Photochem Photobiol Sci 2022; 21:1459-1472. [PMID: 35551642 DOI: 10.1007/s43630-022-00236-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/19/2022] [Indexed: 10/18/2022]
Abstract
Pseudomonas aeruginosa is an extremely versatile microorganism that survives in a wide variety of niches. It is capable to respond rapidly to changes in the environment by producing secondary metabolites and virulence factors, including alginate. Alginate is an extracellular polysaccharide that protects the bacteria from antibiotics and oxidative agents, and enhances cell adhesion to solid surfaces in the process of biofilm formation. In the present study, we analyzed the role of alginate in the response of P. aeruginosa to lethal doses of ultraviolet-A (UVA) radiation, the major fraction of solar UV radiation reaching the Earth's surface. We also studied the role of alginate in the context of the adaptive responses generated when P. aeruginosa is exposed to sublethal doses of UVA radiation. The survival studies demonstrated that alginate has a key role in the resistance of P. aeruginosa to the oxidative stress generated by lethal UVA doses, both in planktonic cells and in static biofilms. In addition, the presence of alginate proved to be essential in the occurrence of adaptive responses such as induction of biofilm formation and cross-protection against hydrogen peroxide and sodium hypochlorite, both generated by exposure to low UVA doses. Finally, we demonstrated that the increase of biofilm formation is accompanied by an increase in alginate concentration in the biofilm matrix, possibly through the ppGpp-dependent induction of genes related to alginate regulation (algR and algU) and biosynthesis (algD operon). Given the importance of alginate in biofilm formation and its protective roles, better understanding of the mechanisms associated to its functions and synthesis is relevant, given the normal exposure of P. aeruginosa to UVA radiation and other types of oxidative stresses.
Collapse
|
8
|
Anju VT, Busi S, Kumar S, Suchiang K, Kumavath R, Ranganathan S, Ampasala DR, Dyavaiah M. Alantolactone modulates the production of quorum sensing mediated virulence factors and biofilm formation in Pseudomonas aeruginosa. BIOFOULING 2022; 38:331-347. [PMID: 35469529 DOI: 10.1080/08927014.2022.2064747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen in immunocompromised patients and accounts for mortality worldwide. Quorum sensing (QS) and QS mediated biofilm formation of P. aeruginosa increase the severity of infection in the host. New and effective therapeutics are in high demand to eliminate Pseudomonas infections. The current study investigated the quorum quenching and biofilm inhibition properties of alantolactone (ATL) against P. aeruginosa PAO1. The production of key virulence factors and biofilm components were affected in bacteria when treated with sub-MIC of ATL and further validated by qRT-PCR studies. The anti-infective potential of ATL was corroborated in an in vivo model with improved survival of infected Caenorhabditis elegans and reduced bacterial colonization. In silico studies suggested the molecular interactions of ATL to QS proteins as stable. Finally, ATL was explored in the present study to inhibit QS pathways and holds the potential to develop into an effective anti-infective agent against P. aeruginosa.
Collapse
Affiliation(s)
- V T Anju
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Siddhardha Busi
- Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Sandeep Kumar
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Kitlangki Suchiang
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Ranjith Kumavath
- Department of Genomic Science, School of Biological Sciences, Central University of Kerala, Kasaragod, Kerala, India
| | - Sampathkumar Ranganathan
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Dinakara Rao Ampasala
- Department of Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Madhu Dyavaiah
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry, India
| |
Collapse
|
9
|
Pezzoni M, De Troch M, Pizarro RA, Costa CS. Homeophasic Adaptation in Response to UVA Radiation in Pseudomonas aeruginosa: Changes of Membrane Fatty Acid Composition and Induction of desA and desB Expression. Photochem Photobiol 2021; 98:886-893. [PMID: 34695237 DOI: 10.1111/php.13548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/22/2021] [Indexed: 11/27/2022]
Abstract
In bacteria, exposure to changes in environmental conditions can alter membrane fluidity, thereby affecting its essential functions in cell physiology. To adapt to these changes, bacteria maintain appropriate fluidity by varying the composition of the fatty acids of membrane phospholipids, a phenomenon known as homeophasic adaptation. In Pseudomonas aeruginosa, this response is achieved mainly by two mechanisms of fatty acid desaturation: the FabA-FabB and DesA-DesB systems. This study analyzed the effect of ultraviolet-A (UVA) radiation-the major fraction of solar UV radiation reaching the Earth's surface-on the homeophasic process. The prototypical strain PAO1 was grown under sublethal UVA doses or in the dark, and the profiles of membrane fatty acids were compared at early logarithmic, logarithmic and stationary growth phases. In the logarithmic growth phase, it was observed that growth under sublethal UVA doses induced the expression of the desaturase-encoding genes desA and desB and increased the proportion of unsaturated fatty acids; in addition, membrane fluidity could also increase, as suggested by the indices used as indicators of this parameter. The opposite effect was observed in the stationary growth phase. These results demonstrate the relevant role of UVA on the homeophasic response at transcriptional level.
Collapse
Affiliation(s)
- Magdalena Pezzoni
- Departamento de Radiobiología, Comisión Nacional de Energía Atómica, San Martin, Argentina
| | | | - Ramón A Pizarro
- Departamento de Radiobiología, Comisión Nacional de Energía Atómica, San Martin, Argentina
| | - Cristina S Costa
- Departamento de Radiobiología, Comisión Nacional de Energía Atómica, San Martin, Argentina
| |
Collapse
|
10
|
Thomas GH. Microbial Musings - August 2020. MICROBIOLOGY-SGM 2020; 166:680-682. [PMID: 32854815 PMCID: PMC7641384 DOI: 10.1099/mic.0.000969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|