1
|
Dessenne C, Ménart B, Acket S, Dewulf G, Guerardel Y, Vidal O, Rossez Y. Lipidomic analyses reveal distinctive variations in homeoviscous adaptation among clinical strains of Acinetobacter baumannii, providing insights from an environmental adaptation perspective. Microbiol Spectr 2024; 12:e0075724. [PMID: 39254344 PMCID: PMC11448061 DOI: 10.1128/spectrum.00757-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 08/07/2024] [Indexed: 09/11/2024] Open
Abstract
Acinetobacter baumannii is known for its antibiotic resistance and is increasingly found outside of healthcare settings. To survive colder temperatures, bacteria, including A. baumannii, adapt by modifying glycerophospholipids (GPL) to maintain membrane flexibility. This study examines the lipid composition of six clinical A. baumannii strains, including the virulent AB5075, at two temperatures. At 18°C, five strains consistently show an increase in palmitoleic acid (C16:1), while ABVal2 uniquely shows an increase in oleic acid (C18:1). LC-HRMS2 analysis identifies shifts in GPL and glycerolipid composition between 18°C and 37°C, highlighting variations in phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) lipids. ABVal2 shows increased PE with C18:1 and C16:1 at 18°C, but no change in PG, in contrast to other strains that show increased PE and PG with C16:1. Notably, although A. baumannii typically lacks FabA, a key enzyme for unsaturated fatty acid synthesis, this enzyme was found in both ABVal2 and ABVal3. In addition, ABVal2 contains five candidate desaturases that may contribute to its lipid profile. The study also reveals variations in strain motility and biofilm formation over temperature. These findings enhance our understanding of A. baumannii's physiological adaptations, survival strategies and ecological fitness in different environments.IMPORTANCEAcinetobacter baumannii, a bacterium known for its resistance to antibiotics, is a concern in healthcare settings. This study focused on understanding how this bacterium adapts to different temperatures and how its lipid composition changes. Lipids are the building blocks of cell membranes. By studying these changes, scientists can gain insights into how the bacterium survives and behaves in various environments. This understanding improves our understanding of its global dissemination capabilities. The results of the study contribute to our broader understanding of how Acinetobacter baumannii works, which is important for developing strategies to combat its impact on patient health.
Collapse
Affiliation(s)
- Clara Dessenne
- Université Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Benoît Ménart
- Centre Hospitalier de valenciennes, Laboratoire de Biologie Hygiène-service de Microbiologie, Valenciennes, France
| | - Sébastien Acket
- Université de technologie de Compiègne, UPJV, UMR CNRS 7025, Enzyme and Cell Engineering, Centre de recherche Royallieu, Compiègne Cedex, Compiègne, France
| | - Gisèle Dewulf
- Centre Hospitalier de valenciennes, Laboratoire de Biologie Hygiène-service de Microbiologie, Valenciennes, France
| | - Yann Guerardel
- Université Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Olivier Vidal
- Université Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Yannick Rossez
- Université Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
- Université de technologie de Compiègne, UPJV, UMR CNRS 7025, Enzyme and Cell Engineering, Centre de recherche Royallieu, Compiègne Cedex, Compiègne, France
| |
Collapse
|
2
|
Haracic E, Waters JK, Nguyen Thi Nguyen T, Kostoulias X, Davies BJ, Yu L, Peleg AY, Bulone V, Short FL, Eijkelkamp BA. Fatty Acid Uptake in Klebsiella pneumoniae and the Landscape of Its Infectious Niches. ACS Infect Dis 2024. [PMID: 39259670 DOI: 10.1021/acsinfecdis.4c00307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
Klebsiella pneumoniae is consistently ranked among the most problematic multidrug-resistant bacterial pathogens in healthcare systems. Developing novel treatments requires a better understanding of its interaction with the host environment. Although bacteria can synthesize fatty acids, emerging findings suggest a potential preference for their acquisition from the host. Fatty acid profiling of mice revealed a dramatic increase in the level of hepatic lipids during K. pneumoniae infection. The K. pneumoniae fatty acid composition and uptake capabilities were found to be largely clonally conserved. Correlations between fatty acid uptake, outer membrane vesicle production, and cell permeability were observed, but this did not translate to alterations in cell morphology, capsule production, or antimicrobial susceptibility. Importantly, hyper-capsulation did not prevent the uptake of hydrophobic fatty acids. The uptake of a saturated fatty acid by hypervirulent K. pneumoniae isolate may provide insights into the clinical association of K. pneumoniae infections with hyperlipidemic and/or obese individuals.
Collapse
Affiliation(s)
- Ella Haracic
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Jack K Waters
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - To Nguyen Thi Nguyen
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3168, Australia
| | - Xenia Kostoulias
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3168, Australia
- Department of Infectious Diseases, Alfred Health and School of Translational Medicine, Monash University, Prahan, VIC 3181, Australia
| | - Brynley J Davies
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Long Yu
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Anton Y Peleg
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3168, Australia
- Department of Infectious Diseases, Alfred Health and School of Translational Medicine, Monash University, Prahan, VIC 3181, Australia
| | - Vincent Bulone
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Francesca L Short
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, VIC 3168, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| |
Collapse
|
3
|
Zheng Y, Chi J, Ou J, Jiang L, Wang L, Luo R, Yan Y, Xu Z, Peng T, Cai J, Wu C, Teng P, Quan G, Lu C. Antibacterial Agents and Adjuvants against Pseudomonas Aeruginosa Infections. Adv Healthc Mater 2024:e2400664. [PMID: 39039988 DOI: 10.1002/adhm.202400664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/21/2024] [Indexed: 07/24/2024]
Abstract
The development of narrow-spectrum antimicrobial agents is paramount for swiftly eradicating pathogenic bacteria, mitigating the onset of drug resistance, and preserving the homeostasis of bacterial microbiota in tissues. Owing to the limited affinity between the hydrophobic lipid bilayer interior of bacterial cells and most hydrophilic, polar peptides, the construction of a distinctive class of four-armed host-defense peptides/peptidomimetics (HDPs) is proposed with enhanced specificity and membrane perturbation capability against Pseudomonas aeruginosa by incorporating imidazole groups. These groups demonstrate substantial affinity for unsaturated phospholipids, which are predominantly expressed in the cell membrane of P. aeruginosa, thereby enabling HDPs to exhibit narrow-spectrum activity against this bacterium. Computational simulations and experimental investigations have corroborated that the imidazole-rich, four-armed peptidomimetics exhibit notable selectivity toward bacteria over mammalian cells. Among them, 4H10, characterized by its abundant and densely distributed imidazole groups, exhibits impressive activity against various clinically isolated P. aeruginosa strains. Moreover, 4H10 has demonstrated potential as an antibiotic adjuvant, enhancing doxycycline accumulation and exerting effects on intracellular targets by efficiently disrupting bacterial cell membranes. Consequently, the hydrogel composed of 4H10 and doxycycline emerged as a promising topical agent, significantly diminishing the skin P. aeruginosa burden by 97.1% within 2 days while inducing minimal local and systemic toxicity.
Collapse
Affiliation(s)
- Yuwei Zheng
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Jiaying Chi
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Jiayu Ou
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Ling Jiang
- Department of Pharmacy, Shantou University Medical College, Shantou, 515041, China
| | - Liqing Wang
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Rui Luo
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Yilang Yan
- Department of Pharmacy, Shantou University Medical College, Shantou, 515041, China
| | - Zejun Xu
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Tingting Peng
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, Tampa, FL, 33620, USA
| | - Chuanbin Wu
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Peng Teng
- National Key Laboratory of Advanced Drug Delivery and Release Systems, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Guilan Quan
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| | - Chao Lu
- State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 511436, China
- College of Pharmacy, Jinan University, Guangzhou, 511436, China
| |
Collapse
|
4
|
Lee TH, Charchar P, Separovic F, Reid GE, Yarovsky I, Aguilar MI. The intricate link between membrane lipid structure and composition and membrane structural properties in bacterial membranes. Chem Sci 2024; 15:3408-3427. [PMID: 38455013 PMCID: PMC10915831 DOI: 10.1039/d3sc04523d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024] Open
Abstract
It is now evident that the cell manipulates lipid composition to regulate different processes such as membrane protein insertion, assembly and function. Moreover, changes in membrane structure and properties, lipid homeostasis during growth and differentiation with associated changes in cell size and shape, and responses to external stress have been related to drug resistance across mammalian species and a range of microorganisms. While it is well known that the biomembrane is a fluid self-assembled nanostructure, the link between the lipid components and the structural properties of the lipid bilayer are not well understood. This perspective aims to address this topic with a view to a more detailed understanding of the factors that regulate bilayer structure and flexibility. We describe a selection of recent studies that address the dynamic nature of bacterial lipid diversity and membrane properties in response to stress conditions. This emerging area has important implications for a broad range of cellular processes and may open new avenues of drug design for selective cell targeting.
Collapse
Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
| | - Patrick Charchar
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
| | - Gavin E Reid
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
- Department of Biochemistry and Pharmacology, University of Melbourne Parkville VIC 3010 Australia
| | - Irene Yarovsky
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
| |
Collapse
|
5
|
Cronan JE. Unsaturated fatty acid synthesis in bacteria: Mechanisms and regulation of canonical and remarkably noncanonical pathways. Biochimie 2024; 218:137-151. [PMID: 37683993 PMCID: PMC10915108 DOI: 10.1016/j.biochi.2023.09.007] [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: 06/19/2023] [Revised: 08/02/2023] [Accepted: 09/04/2023] [Indexed: 09/10/2023]
Abstract
Unsaturated phospholipid acyl chains are required for membrane function in most bacteria. The double bonds of the cis monoenoic chains arise by two distinct pathways depending on whether oxygen is required. The oxygen-independent pathway (traditionally called the anaerobic pathway) introduces the cis double bond by isomerization of the trans double bond intermediate of the fatty acid elongation cycle. Double bond isomerization occurs at an intermediate chain length (e.g., C10) and the isomerization product is elongated to the C16-C18 chains that become phospholipid monoenoic acyl chains. This pathway was first delineated in Escherichia coli and became the paradigm pathway. However, studies of other bacteria show deviations from this paradigm, the most exceptional being reversal of the fatty acid elongation cycle by a reaction paralleling the initial step in the β-oxidative degradation of fatty acids. In the oxygen-dependent pathway diiron enzymes called desaturases introduce a double bond into a saturated acyl chain by regioselective cis dehydrogenation through activation of molecular oxygen with an active-site diiron cluster. This difficult hydrogen abstraction from a methylene group often occurs at the midpoint of a saturated fatty acyl chain. In bacteria the acyl chain is a phospholipid acyl chain, and the desaturase is membrane bound. Both the oxygen-independent oxygen-dependent pathways are transcriptionally regulated by repressor and activator proteins that respond to small molecule ligands such as acyl-CoAs. However, in Bacillus subtilis the desaturase is synthesized only at low growth temperatures, a process controlled by a signal transduction regulatory pathway dependent on membrane lipid properties.
Collapse
Affiliation(s)
- John E Cronan
- Departments of Microbiology and Biochemistry, University of Illinois, Urbana, 61801, USA.
| |
Collapse
|
6
|
Ostroumova OS, Efimova SS. Lipid-Centric Approaches in Combating Infectious Diseases: Antibacterials, Antifungals and Antivirals with Lipid-Associated Mechanisms of Action. Antibiotics (Basel) 2023; 12:1716. [PMID: 38136750 PMCID: PMC10741038 DOI: 10.3390/antibiotics12121716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
One of the global challenges of the 21st century is the increase in mortality from infectious diseases against the backdrop of the spread of antibiotic-resistant pathogenic microorganisms. In this regard, it is worth targeting antibacterials towards the membranes of pathogens that are quite conservative and not amenable to elimination. This review is an attempt to critically analyze the possibilities of targeting antimicrobial agents towards enzymes involved in pathogen lipid biosynthesis or towards bacterial, fungal, and viral lipid membranes, to increase the permeability via pore formation and to modulate the membranes' properties in a manner that makes them incompatible with the pathogen's life cycle. This review discusses the advantages and disadvantages of each approach in the search for highly effective but nontoxic antimicrobial agents. Examples of compounds with a proven molecular mechanism of action are presented, and the types of the most promising pharmacophores for further research and the improvement of the characteristics of antibiotics are discussed. The strategies that pathogens use for survival in terms of modulating the lipid composition and physical properties of the membrane, achieving a balance between resistance to antibiotics and the ability to facilitate all necessary transport and signaling processes, are also considered.
Collapse
Affiliation(s)
- Olga S. Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg 194064, Russia;
| | | |
Collapse
|
7
|
Dong H, Cronan JE. Suppressor mutants demonstrate the metabolic plasticity of unsaturated fatty acid synthesis in Pseudomonas aeruginosa PAO1. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001400. [PMID: 37818937 PMCID: PMC10634369 DOI: 10.1099/mic.0.001400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
Pseudomonas aeruginosa PAO1 has two aerobic pathways for synthesis of unsaturated fatty acids (UFAs), DesA and DesB plus the oxygen independent FabAB pathway. The DesA desaturase acts on saturated acyl chains of membrane phospholipid bilayers whereas the substrates of the DesB desaturase are thought to be long chain saturated acyl-CoA thioesters derived from exogeneous saturated fatty acids that are required to support DesB-dependent growth. Under suitable aerobic conditions either of these membrane-bound desaturates can support growth of P. aeruginosa ∆fabA strains lacking the oxygen independent FabAB pathway. We previously studied function of the desA desaturase of P. putida in a P. aeruginosa ∆fabA ∆desA strain that required supplementation with a UFA for growth and noted bypass suppression of the P. aeruginosa ∆fabA ∆desA strain that restored UFA synthesis. We report three genes encoding lipid metabolism proteins that give rise to suppressor strains that bypass loss of the DesA and oxygen independent FabAB pathways.
Collapse
Affiliation(s)
- Huijuan Dong
- Departments of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - John E. Cronan
- Departments of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Departments of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
8
|
Takeno S, Hirata Y, Kitamura K, Ohtake T, Aoki K, Murata N, Hayashi M, Ikeda M. Metabolic engineering to produce palmitic acid or palmitoleic acid in an oleic acid-producing Corynebacterium glutamicum strain. Metab Eng 2023; 78:148-158. [PMID: 37286071 DOI: 10.1016/j.ymben.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/14/2023] [Accepted: 06/04/2023] [Indexed: 06/09/2023]
Abstract
Focusing on the differences in the catalytic properties of two type I fatty acid synthases FasA and FasB, the fasA gene was disrupted in an oleic acid-producing Corynebacterium glutamicum strain. The resulting oleic acid-requiring strain whose fatty acid synthesis depends only on FasB exhibited almost exclusive production (217 mg/L) of palmitic acid (C16:0) from 1% glucose under the conditions supplemented with the minimum concentration of sodium oleate for growth. Plasmid-mediated amplification of fasB led to a 1.47-fold increase in palmitic acid production (320 mg/L), while fasB disruption resulted in no fatty acid production, with excretion of malonic acid (30 mg/L). Next, aiming at conversion of the palmitic acid producer to a producer of palmitoleic acid (POA, C16:1Δ9), we introduced the Pseudomonas nitroreducens Δ9-desaturase genes desBC into the palmitic acid producer. Although this resulted in failure, we noticed the emergence of suppressor mutants that exhibited the oleic acid-non-requiring phenotype. Production experiments revealed that one such mutant M-1 undoubtedly produced POA (17 mg/L) together with palmitic acid (173 mg/L). Whole genomic analysis and subsequent genetic analysis identified the suppressor mutation of strain M-1 as a loss-of-function mutation for the DtxR protein, a global regulator of iron metabolism. Considering that DesBC are both iron-containing enzymes, we investigated the conditions for increased iron availability to improve the DesBC-dependent conversion ratio of palmitic acid to POA. Eventually, supplementation of both hemin and the iron chelator protocatechuic acid in the engineered strain dramatically enhanced POA production to 161 mg/L with a conversion ratio of 80.1%. Cellular fatty acid analysis revealed that the POA-producing cells were really equipped with unnatural membrane lipids comprised predominantly of palmitic acid (85.1% of total cellular fatty acids), followed by non-native POA (12.4%).
Collapse
Affiliation(s)
- Seiki Takeno
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Yosuke Hirata
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Kako Kitamura
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Tatsunori Ohtake
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Kuniyoshi Aoki
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Noriko Murata
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan
| | - Mikiro Hayashi
- Bioprocess Development Center, Kyowa Hakko Bio Co., Ltd., Tsukuba, Ibaraki, Japan
| | - Masato Ikeda
- Department of Agricultural and Life Sciences, Faculty of Agriculture, Shinshu University, Nagano, Japan.
| |
Collapse
|
9
|
Tian L, Yang Z, Wang J, Liu J. Analysis of the Plasmid-Based ts-Mutant Δ fabA/pTS-fabA Reveals Its Lethality under Aerobic Growth Conditions That Is Suppressed by Mild Overexpression of desA at a Restrictive Temperature in Pseudomonas aeruginosa. Microbiol Spectr 2023; 11:e0133823. [PMID: 37191499 PMCID: PMC10269440 DOI: 10.1128/spectrum.01338-23] [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: 03/31/2023] [Accepted: 04/29/2023] [Indexed: 05/17/2023] Open
Abstract
It is uncertain whether PA1610|fabA is essential or dispensable for growth on LB-agar plates under aerobic conditions in Pseudomonas aeruginosa PAO1. To examine its essentiality, we disrupted fabA in the presence of a native promoter-controlled complementary copy on ts-plasmid. In this analysis, we showed that the plasmid-based ts-mutant ΔfabA/pTS-fabA failed to grow at a restrictive temperature, consistent with the observation by Hoang and Schweizer (T. T. Hoang, H. P. Schweizer, J Bacteriol 179:5326-5332, 1997, https://doi.org/10.1128/jb.179.17.5326-5332.1997), and expanded on this by showing that ΔfabA exhibited curved cell morphology. On the other hand, strong induction of fabA-OE or PA3645|fabZ-OE impeded the growth of cells displaying oval morphology. Suppressor analysis revealed a mutant sup gene that suppressed a growth defect but not cell morphology of ΔfabA. Genome resequencing and transcriptomic profiling of sup identified PA0286|desA, whose promoter carried a single-nucleotide polymorphism (SNP), and transcription was significantly upregulated (level increase of >2-fold, P < 0.05). By integration of the SNP-bearing promoter-controlled desA gene into the chromosome of ΔfabA/pTS-fabA, we showed that the SNP is sufficient for ΔfabA to phenocopy the sup mutant. Furthermore, mild induction of the araC-PBAD-controlled desA gene but not desB rescued ΔfabA. These results validated that mild overexpression of desA fully suppressed the lethality but not the curved cell morphology of ΔfabA. Similarly, Zhu et al. (Zhu K, Choi K-H, Schweizer HP, Rock CO, Zhang Y-M, Mol Microbiol 60:260-273, 2006, https://doi.org/10.1111/j.1365-2958.2006.05088.x) showed that multicopy desA partially alleviated the slow growth phenotype of ΔfabA, the difference in which was that ΔfabA was viable. Taken together, our results demonstrate that fabA is essential for aerobic growth. We propose that the plasmid-based ts-allele is useful for exploring the genetic suppression interaction of essential genes of interest in P. aeruginosa. IMPORTANCE Pseudomonas aeruginosa is an opportunistic pathogen whose multidrug resistance demands new drug development. Fatty acids are essential for viability, and essential genes are ideal drug targets. However, the growth defect of essential gene mutants can be suppressed. Suppressors tend to be accumulated during the construction of essential gene deletion mutants, hampering the genetic analysis. To circumvent this issue, we constructed a deletion allele of fabA in the presence of a native promoter-controlled complementary copy in the ts-plasmid. In this analysis, we showed that ΔfabA/pTS-fabA failed to grow at a restrictive temperature, supporting its essentiality. Suppressor analysis revealed desA, whose promoter carried a SNP and whose transcription was upregulated. We validated that both the SNP-bearing promoter-controlled and regulable PBAD promoter-controlled desA suppressed the lethality of ΔfabA. Together, our results demonstrate that fabA is essential for aerobic growth. We propose that plasmid-based ts-alleles are suitable for genetic analysis of essential genes of interest.
Collapse
Affiliation(s)
- Liyan Tian
- Systems Biology, School of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China
| | - Zhili Yang
- Systems Biology, School of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China
| | - Jianxin Wang
- Systems Biology, School of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China
| | - Jianhua Liu
- Systems Biology, School of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, Zhejiang, China
| |
Collapse
|
10
|
Strategies to Enhance the Biosynthesis of Monounsaturated Fatty Acids in Escherichia coli. BIOTECHNOL BIOPROC E 2023. [DOI: 10.1007/s12257-022-0295-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
|
11
|
Yu YH, Chen C, Ma JR, Zhang YY, Yan MF, Zhang WB, Hu Z, Wang HH, Ma JC. The FabA-FabB Pathway Is Not Essential for Unsaturated Fatty Acid Synthesis but Modulates Diffusible Signal Factor Synthesis in Xanthomonas campestris pv. campestris. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:119-130. [PMID: 36515967 DOI: 10.1094/mpmi-09-22-0182-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Most bacteria use type II fatty acid synthesis (FAS) systems for synthesizing fatty acids, of which the conserved FabA-FabB pathway is considered to be crucial for unsaturated fatty acid (UFA) synthesis in gram-negative bacteria. Xanthomonas campestris pv. campestris, the phytopathogen of black rot disease in crucifers, produces higher quantities of UFAs under low-temperature conditions for increasing membrane fluidity. The fabA and fabB genes were identified in the X. campestris pv. campestris genome by BLAST analysis; however, the growth of the X. campestris pv. campestris fabA and fabB deletion mutants was comparable to that of the wild-type strain in nutrient and minimal media. The X. campestris pv. campestris ΔfabA and ΔfabB strains produced large quantities of UFAs and, altogether, these results indicated that the FabA-FabB pathway is not essential for growth or UFA synthesis in X. campestris pv. campestris. We also observed that the expression of X. campestris pv. campestris fabA and fabB restored the growth of the temperature-sensitive Escherichia coli fabA and fabB mutants CL104 and CY242, respectively, under non-permissive conditions. The in-vitro assays demonstrated that the FabA and FabB proteins of X. campestris pv. campestris catalyzed FAS. Our study also demonstrated that the production of diffusible signal factor family signals that mediate quorum sensing was higher in the X. campestris pv. campestris ΔfabA and ΔfabB strains and greatly reduced in the complementary strains, which exhibited reduced swimming motility and attenuated host-plant pathogenicity. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
Collapse
Affiliation(s)
- Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Cheng Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jian-Rong Ma
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
| | - Yuan-Yin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Ming-Feng Yan
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| |
Collapse
|
12
|
Dong H, Wang H, Cronan JE. Divergent unsaturated fatty acid synthesis in two highly related model pseudomonads. Mol Microbiol 2023; 119:252-261. [PMID: 36537550 DOI: 10.1111/mmi.15018] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/15/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
The genomes of the best-studied pseudomonads, Pseudomonas aeruginosa and Pseudomonas putida, which share 85% of the predicted coding regions, contain a fabA fabB operon (demonstrated in P. aeruginosa, putative in P. putida). The enzymes encoded by the fabA and fabB genes catalyze the introduction of a double bond into a 10-carbon precursor which is elongated to the 16:1Δ9 and 18:1Δ11 unsaturated fatty acyl chains required for functional membrane phospholipids. A detailed analysis of transcription of the P. putida fabA fabB gene cluster showed that fabA and fabB constitute an operon and disclosed an unexpected and essential fabB promoter located within the fabA coding sequence. Inactivation of the fabA fabB operon fails to halt the growth of P. aeruginosa PAO1 but blocks growth of P. putida F1 unless an exogenous unsaturated fatty acid is provided. We report that the asymmetry between these two species is due to the P. aeruginosa PAO1 desA gene which encodes a fatty acid desaturase that introduces double bonds into the 16-carbon acyl chains of membrane phospholipids. Although P. putida F1 encodes a putative DesA homolog that is 84% identical to the P. aeruginosa PAO1, the protein fails to provide sufficient unsaturated fatty acid synthesis for growth when the FabA FabB pathway is inactivated. We report that the P. putida F1 DesA homolog can functionally replace the P. aeruginosa DesA. Hence, the defect in P. putida F1 desaturation is not due to a defective P. putida F1 DesA protein but probably to a weakly active component of the electron transfer process.
Collapse
Affiliation(s)
- Huijuan Dong
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - John E Cronan
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.,Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| |
Collapse
|
13
|
Ugwuodo CJ, Colosimo F, Adhikari J, Shen Y, Badireddy AR, Mouser PJ. Salinity and hydraulic retention time induce membrane phospholipid acyl chain remodeling in Halanaerobium congolense WG10 and mixed cultures from hydraulically fractured shale wells. Front Microbiol 2022; 13:1023575. [PMID: 36439785 PMCID: PMC9687094 DOI: 10.3389/fmicb.2022.1023575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2023] Open
Abstract
Bacteria remodel their plasma membrane lipidome to maintain key biophysical attributes in response to ecological disturbances. For Halanaerobium and other anaerobic halotolerant taxa that persist in hydraulically fractured deep subsurface shale reservoirs, salinity, and hydraulic retention time (HRT) are important perturbants of cell membrane structure, yet their effects remain poorly understood. Membrane-linked activities underlie in situ microbial growth kinetics and physiologies which drive biogeochemical reactions in engineered subsurface systems. Hence, we used gas chromatography-mass spectrometry (GC-MS) to investigate the effects of salinity and HRT on the phospholipid fatty acid composition of H. congolense WG10 and mixed enrichment cultures from hydraulically fractured shale wells. We also coupled acyl chain remodeling to membrane mechanics by measuring bilayer elasticity using atomic force microscopy (AFM). For these experiments, cultures were grown in a chemostat vessel operated in continuous flow mode under strict anoxia and constant stirring. Our findings show that salinity and HRT induce significant changes in membrane fatty acid chemistry of H. congolense WG10 in distinct and complementary ways. Notably, under nonoptimal salt concentrations (7% and 20% NaCl), H. congolense WG10 elevates the portion of polyunsaturated fatty acids (PUFAs) in its membrane, and this results in an apparent increase in fluidity (homeoviscous adaptation principle) and thickness. Double bond index (DBI) and mean chain length (MCL) were used as proxies for membrane fluidity and thickness, respectively. These results provide new insight into our understanding of how environmental and engineered factors might disrupt the physical and biogeochemical equilibria of fractured shale by inducing physiologically relevant changes in the membrane fatty acid chemistry of persistent microbial taxa. GRAPHICAL ABSTRACTSalinity significantly alters membrane bilayer fluidity and thickness in Halanaerobium congolense WG10.
Collapse
Affiliation(s)
- Chika Jude Ugwuodo
- Natural Resources and Earth Systems Science, University of New Hampshire, Durham, NH, United States
- Department of Civil and Environmental Engineering, University of New Hampshire, Durham, NH, United States
| | | | - Jishnu Adhikari
- Sanborn, Head and Associates, Inc., Concord, NH, United States
| | - Yuxiang Shen
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States
| | - Appala Raju Badireddy
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States
| | - Paula J. Mouser
- Department of Civil and Environmental Engineering, University of New Hampshire, Durham, NH, United States
| |
Collapse
|
14
|
Chen A, Mindrebo JT, Davis TD, Kim WE, Katsuyama Y, Jiang Z, Ohnishi Y, Noel JP, Burkart MD. Mechanism-based cross-linking probes capture the Escherichia coli ketosynthase FabB in conformationally distinct catalytic states. Acta Crystallogr D Struct Biol 2022; 78:1171-1179. [PMID: 36048156 PMCID: PMC9435599 DOI: 10.1107/s2059798322007434] [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: 04/12/2022] [Accepted: 07/20/2022] [Indexed: 11/10/2022] Open
Abstract
Ketosynthases (KSs) catalyse essential carbon-carbon bond-forming reactions in fatty-acid biosynthesis using a two-step, ping-pong reaction mechanism. In Escherichia coli, there are two homodimeric elongating KSs, FabB and FabF, which possess overlapping substrate selectivity. However, FabB is essential for the biosynthesis of the unsaturated fatty acids (UFAs) required for cell survival in the absence of exogenous UFAs. Additionally, FabB has reduced activity towards substrates longer than 12 C atoms, whereas FabF efficiently catalyses the elongation of saturated C14 and unsaturated C16:1 acyl-acyl carrier protein (ACP) complexes. In this study, two cross-linked crystal structures of FabB in complex with ACPs functionalized with long-chain fatty-acid cross-linking probes that approximate catalytic steps were solved. Both homodimeric structures possess asymmetric substrate-binding pockets suggestive of cooperative relationships between the two FabB monomers when engaged with C14 and C16 acyl chains. In addition, these structures capture an unusual rotamer of the active-site gating residue, Phe392, which is potentially representative of the catalytic state prior to substrate release. These structures demonstrate the utility of mechanism-based cross-linking methods to capture and elucidate conformational transitions accompanying KS-mediated catalysis at near-atomic resolution.
Collapse
Affiliation(s)
- Aochiu Chen
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jeffrey T. Mindrebo
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- Jack H. Skirball Center for Chemical Biology and Proteomics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Tony D. Davis
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Woojoo E. Kim
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Yohei Katsuyama
- Department of Biotechnology, The Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Ziran Jiang
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Yasuo Ohnishi
- Department of Biotechnology, The Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Joseph P. Noel
- Jack H. Skirball Center for Chemical Biology and Proteomics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Michael D. Burkart
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| |
Collapse
|
15
|
Contribution of Membrane Vesicle to Reprogramming of Bacterial Membrane Fluidity in Pseudomonas aeruginosa. mSphere 2022; 7:e0018722. [PMID: 35603537 PMCID: PMC9241526 DOI: 10.1128/msphere.00187-22] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen capable of resisting environmental insults by applying various strategies, including regulating membrane fluidity and producing membrane vesicles (MVs). This study examined the difference in membrane fluidity between planktonic and biofilm modes of growth in P. aeruginosa and whether the ability to alter membrane rigidity in P. aeruginosa could be transferred via MVs. To this end, planktonic and biofilm P. aeruginosa were compared with respect to the lipid composition of their membranes and their MVs and the expression of genes contributing to alteration of membrane fluidity. Additionally, viscosity maps of the bacterial membrane in planktonic and biofilm lifestyles and under the effect of incubation with bacterial MVs were obtained. Further, the growth rate and biofilm formation capability of P. aeruginosa in the presence of MVs were compared. Results showed that the membrane of the biofilm bacteria is significantly less fluid than the membrane of the planktonic bacteria and is enriched with saturated fatty acids. Moreover, the enzymes involved in altering the structure of existing lipids and favoring membrane rigidification are overexpressed in the biofilm bacteria. MVs of biofilm P. aeruginosa elicit membrane rigidification and delay the bacterial growth in the planktonic lifestyle; conversely, they enhance biofilm development in P. aeruginosa. Overall, the study describes the interplay between the planktonic and biofilm bacteria by shedding light on the role of MVs in altering membrane fluidity. IMPORTANCE Membrane rigidification is a survival strategy in Pseudomonas aeruginosa exposed to stress. Despite various studies dedicated to the mechanism behind this phenomenon, not much attention has been paid to the contribution of the bacterial membrane vesicles (MVs) in this regard. This study revealed that P. aeruginosa rigidifies its membrane in the biofilm mode of growth. Additionally, the capability of decreasing membrane fluidity is transferable to the bacterial population via the bacterial MVs, resulting in reprogramming of bacterial membrane fluidity. Given the importance of membrane rigidification for decreasing the pathogen’s susceptibility to antimicrobials, elucidation of the conditions leading to such biophysicochemical modulation of the P. aeruginosa membrane should be considered for the purpose of developing therapeutic approaches against this resistant pathogen.
Collapse
|
16
|
Shao S, Zhang Y, Yin K, Zhang Y, Wei L, Wang Q. FabR senses long-chain unsaturated fatty acids to control virulence in pathogen Edwardsiella piscicida. Mol Microbiol 2022; 117:737-753. [PMID: 34932231 DOI: 10.1111/mmi.14869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/11/2021] [Accepted: 12/18/2021] [Indexed: 11/28/2022]
Abstract
Long-chain unsaturated fatty acids (UFAs) can serve as nutrient sources or building blocks for bacterial membranes. However, little is known about how UFAs may be incorporated into the virulence programs of pathogens. A previous investigation identified FabR as a positive regulator of virulence gene expression in Edwardsiella piscicida. Here, chromatin immunoprecipitation-sequencing coupled with RNA-seq analyses revealed that 10 genes were under the direct control of FabR, including fabA, fabB, and cfa, which modulate the composition of UFAs. The binding of FabR to its target DNA was facilitated by oleoyl-CoA and inhibited by stearoyl-CoA. In addition, analyses of enzyme mobility shift assay and DNase I footprinting with wild-type and a null mutant (F131A) of FabR demonstrated crucial roles of FabR in binding to the promoters of fabA, fabB, and cfa. Moreover, FabR also binds to the promoter region of the virulence regulator esrB for its activation, facilitating the expression of the type III secretion system (T3SS) in response to UFAs. Furthermore, FabR coordinated with RpoS to modulate the expression of T3SS. Collectively, our results elucidate the molecular machinery of FabR regulating bacterial fatty acid composition and virulence in enteric pathogens, further expanding our knowledge of its crucial role in host-pathogen interactions.
Collapse
Affiliation(s)
- Shuai Shao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yi Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Kaiyu Yin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yuanxing Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Lifan Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Department of Endodontics and Operative Dentistry, Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| |
Collapse
|
17
|
Cooper C, Peterson EJR, Bailo R, Pan M, Singh A, Moynihan P, Nakaya M, Fujiwara N, Baliga N, Bhatt A. MadR mediates acyl CoA-dependent regulation of mycolic acid desaturation in mycobacteria. Proc Natl Acad Sci U S A 2022; 119:e2111059119. [PMID: 35165190 PMCID: PMC8872791 DOI: 10.1073/pnas.2111059119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/28/2021] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis has a lipid-rich cell envelope that is remodeled throughout infection to enable adaptation within the host. Few transcriptional regulators have been characterized that coordinate synthesis of mycolic acids, the major cell wall lipids of mycobacteria. Here, we show that the mycolic acid desaturase regulator (MadR), a transcriptional repressor of the mycolate desaturase genes desA1 and desA2, controls mycolic acid desaturation and biosynthesis in response to cell envelope stress. A madR-null mutant of M. smegmatis exhibited traits of an impaired cell wall with an altered outer mycomembrane, accumulation of a desaturated α-mycolate, susceptibility to antimycobacterials, and cell surface disruption. Transcriptomic profiling showed that enriched lipid metabolism genes that were significantly down-regulated upon madR deletion included acyl-coenzyme A (aceyl-CoA) dehydrogenases, implicating it in the indirect control of β-oxidation pathways. Electromobility shift assays and binding affinities suggest a unique acyl-CoA pool-sensing mechanism, whereby MadR is able to bind a range of acyl-CoAs, including those with unsaturated as well as saturated acyl chains. MadR repression of desA1/desA2 is relieved upon binding of saturated acyl-CoAs of chain length C16 to C24, while no impact is observed upon binding of shorter chain and unsaturated acyl-CoAs. We propose this mechanism of regulation as distinct to other mycolic acid and fatty acid synthesis regulators and place MadR as the key regulatory checkpoint that coordinates mycolic acid remodeling during infection in response to host-derived cell surface perturbation.
Collapse
Affiliation(s)
- Charlotte Cooper
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | | | - Rebeca Bailo
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Min Pan
- Institute for Systems Biology, Seattle, WA 98109
| | - Albel Singh
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Patrick Moynihan
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | | | - Nagatoshi Fujiwara
- Department of Food and Nutrition, Faculty of Contemporary Human Life Science, Tezukayama University, Nara 631-8585, Japan
| | - Nitin Baliga
- Institute for Systems Biology, Seattle, WA 98109;
- Department of Biology, University of Washington, Seattle, WA 98105
- Department of Microbiology, University of Washington, Seattle, WA 98105
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98105
- Lawrence Berkeley National Lab, Berkeley, CA 94720
| | - Apoorva Bhatt
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| |
Collapse
|
18
|
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
|
19
|
Frank MW, Whaley SG, Rock CO. Branched-chain amino acid metabolism controls membrane phospholipid structure in Staphylococcus aureus. J Biol Chem 2021; 297:101255. [PMID: 34592315 PMCID: PMC8524195 DOI: 10.1016/j.jbc.2021.101255] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/12/2021] [Accepted: 09/14/2021] [Indexed: 11/30/2022] Open
Abstract
Branched-chain amino acids (primarily isoleucine) are important regulators of virulence and are converted to precursor molecules used to initiate fatty acid synthesis in Staphylococcus aureus. Defining how bacteria control their membrane phospholipid composition is key to understanding their adaptation to different environments. Here, we used mass tracing experiments to show that extracellular isoleucine is preferentially metabolized by the branched-chain ketoacid dehydrogenase complex, in contrast to valine, which is not efficiently converted to isobutyryl-CoA. This selectivity creates a ratio of anteiso:iso C5-CoAs that matches the anteiso:iso ratio in membrane phospholipids, indicating indiscriminate utilization of these precursors by the initiation condensing enzyme FabH. Lipidomics analysis showed that removal of isoleucine and leucine from the medium led to the replacement of phospholipid molecular species containing anteiso/iso 17- and 19-carbon fatty acids with 18- and 20-carbon straight-chain fatty acids. This compositional change is driven by an increase in the acetyl-CoA:C5-CoA ratio, enhancing the utilization of acetyl-CoA by FabH. The acyl carrier protein (ACP) pool normally consists of odd carbon acyl-ACP intermediates, but when branched-chain amino acids are absent from the environment, there was a large increase in even carbon acyl-ACP pathway intermediates. The high substrate selectivity of PlsC ensures that, in the presence or the absence of extracellular Ile/Leu, the 2-position is occupied by a branched-chain 15-carbon fatty acid. These metabolomic measurements show how the metabolism of isoleucine and leucine, rather than the selectivity of FabH, control the structure of membrane phospholipids.
Collapse
Affiliation(s)
- Matthew W Frank
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Sarah G Whaley
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Charles O Rock
- Department of Infectious Diseases, St Jude Children's Research Hospital, Memphis, Tennessee, USA.
| |
Collapse
|
20
|
Adams FG, Pokhrel A, Brazel EB, Semenec L, Li L, Trappetti C, Paton JC, Cain AK, Paulsen IT, Eijkelkamp BA. Acinetobacter baumannii Fatty Acid Desaturases Facilitate Survival in Distinct Environments. ACS Infect Dis 2021; 7:2221-2228. [PMID: 34100578 DOI: 10.1021/acsinfecdis.1c00192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Maintaining optimal fluidity is essential to ensure adequate membrane structure and function under different environmental conditions. We apply integrated molecular approaches to characterize two desaturases (DesA and DesB) and define their specific roles in unsaturated fatty acid (UFA) production in Acinetobacter baumannii. Using a murine model, we reveal DesA to play a minor role in colonization of the respiratory tract, whereas DesB is important during invasive disease. Furthermore, using transcriptomic and bioinformatic analyses, a global regulator involved in fatty acid homeostasis and members of its regulon are characterized. Collectively, we show that DesA and DesB are primary contributors to UFA production in A. baumannii with infection studies illustrating that these distinct desaturases aid in the bacterium's ability to survive in multiple host niches. Hence, this study provides novel insights into the fundamentals of A. baumannii lipid biology, which contributes to the versatility of this critical bacterial pathogen.
Collapse
Affiliation(s)
- Felise G. Adams
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Alaska Pokhrel
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Erin B. Brazel
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Lucie Semenec
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Liping Li
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Claudia Trappetti
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - James C. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Amy K. Cain
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Ian T. Paulsen
- Department of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Bart A. Eijkelkamp
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| |
Collapse
|
21
|
Dong H, Ma J, Chen Q, Chen B, Liang L, Liao Y, Song Y, Wang H, Cronan JE. A cryptic long-chain 3-ketoacyl-ACP synthase in the Pseudomonas putida F1 unsaturated fatty acid synthesis pathway. J Biol Chem 2021; 297:100920. [PMID: 34181948 PMCID: PMC8319022 DOI: 10.1016/j.jbc.2021.100920] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/08/2021] [Accepted: 06/23/2021] [Indexed: 11/30/2022] Open
Abstract
The Pseudomonas putida F1 genome contains five genes annotated as encoding 3-ketoacyl-acyl carrier protein (ACP) synthases. Four are annotated as encoding FabF (3-ketoacyl-ACP synthase II) proteins, and the fifth is annotated as encoding a FabB (3-ketoacyl-ACP synthase I) protein. Expression of one of the FabF proteins, FabF2, is cryptic in the native host and becomes physiologically important only when the repressor controlling fabF2 transcription is inactivated. When derepressed, FabF2 can functionally replace FabB, and when expressed from a foreign promoter, had weak FabF activity. Complementation of Escherichia coli fabB and fabF mutant strains with high expression showed that P. putida fabF1 restored E. coli fabF function, whereas fabB restored E. coli fabB function and fabF2 restored the functions of both E. coli fabF and fabB. The P. putida ΔfabF1 deletion strain was almost entirely defective in synthesis of cis-vaccenic acid, whereas the ΔfabB strain is an unsaturated fatty acid (UFA) auxotroph that accumulated high levels of spontaneous suppressors in the absence of UFA supplementation. This was due to increased expression of fabF2 that bypasses loss of fabB because of the inactivation of the regulator, Pput_2425, encoded in the same operon as fabF2. Spontaneous suppressor accumulation was decreased by high levels of UFA supplementation, whereas competition by the P. putida β-oxidation pathway gave increased accumulation. The ΔfabB ΔfabF2 strain is a stable UFA auxotroph indicating that suppressor accumulation requires FabF2 function. However, at low concentrations of UFA supplementation, the ΔfabF2 ΔPput_2425 double-mutant strain still accumulated suppressors at low UFA concentrations.
Collapse
Affiliation(s)
- Huijuan Dong
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China; Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Jincheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Qunyi Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Bo Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Lujie Liang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yulu Song
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China.
| | - John E Cronan
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
| |
Collapse
|
22
|
Effects of Fruit Maturity Stages on GC-FID Fatty Acid Profiles, Phenolic Contents, and Biological Activities of Eucalyptus marginata L. J FOOD QUALITY 2021. [DOI: 10.1155/2021/5546969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The objective of this study was to determine the impact of development stages of Eucalyptus marginata’s fruits on the fatty acid composition as well as on phenolic, flavonoid, and tannin contents of oils. Taking into account fruit maturity stages, vegetable oils have been evaluated for their biological potentials. Fatty acid profiles were quantified using gas chromatography (GC) coupled to a flame ionization detector (FID). The fatty acid profiles of oils obtained from mature fruits showed highest linoleic acid content (49.21%) and Z-vaccenic (C18:1n-7) + oleic (C18:1n-9) acids (22.40%) and a low content of linolenic acid (C18:3) (1.59%). On the other hand, the major saturated fatty acid compound found in the oil of immature Eucalyptus marginata fruits was palmitic acid (C16:0) with about 27%. Based on the Folin–Ciocalteau method, the obtained results revealed a significant difference in the contents of total polyphenols, flavonoids, and tannins according to the stage of fruit maturity (
). Furthermore, the detected antimicrobial potentials were related to the fruit maturity stage. While both veg\etable oils extracted from mature and immature Eucalyptus marginata fruits exhibited notable antibacterial activities against the species Staphylococcus aureus, Enterococcus faecalis, Serratia marcescens, and Escherichia coli, only the oils extracted from immature fruits exhibited an antifungal activity against Candida parapsilosis.
Collapse
|
23
|
Genetic Suppression of Lethal Mutations in Fatty Acid Biosynthesis Mediated by a Secondary Lipid Synthase. Appl Environ Microbiol 2021; 87:e0003521. [PMID: 33837011 PMCID: PMC8174602 DOI: 10.1128/aem.00035-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The biosynthesis and incorporation of polyunsaturated fatty acids into phospholipid membranes are unique features of certain marine Gammaproteobacteria inhabiting high-pressure and/or low-temperature environments. In these bacteria, monounsaturated and saturated fatty acids are produced via the classical dissociated type II fatty acid synthase mechanism, while omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) are produced by a hybrid polyketide/fatty acid synthase—encoded by the pfa genes—also referred to as the secondary lipid synthase mechanism. In this work, phenotypes associated with partial or complete loss of monounsaturated biosynthesis are shown to be compensated for by severalfold increased production of polyunsaturated fatty acids in the model marine bacterium Photobacterium profundum SS9. One route to suppression of these phenotypes could be achieved by transposition of insertion sequences within or upstream of the fabD coding sequence, which encodes malonyl coenzyme A (malonyl-CoA) acyl carrier protein transacylase. Genetic experiments in this strain indicated that fabD is not an essential gene, yet mutations in fabD and pfaA are synthetically lethal. Based on these results, we speculated that the malonyl-CoA transacylase domain within PfaA compensates for loss of FabD activity. Heterologous expression of either pfaABCD from P. profundum SS9 or pfaABCDE from Shewanella pealeana in Escherichia coli complemented the loss of the chromosomal copy of fabD in vivo. The co-occurrence of independent, yet compensatory, fatty acid biosynthetic pathways in selected marine bacteria may provide genetic redundancy to optimize fitness under extreme conditions. IMPORTANCE A defining trait among many cultured piezophilic and/or psychrophilic marine Gammaproteobacteria is the incorporation of both monounsaturated and polyunsaturated fatty acids into membrane phospholipids. The biosynthesis of these different classes of fatty acid molecules is linked to two genetically distinct co-occurring pathways that utilize the same pool of intracellular precursors. Using a genetic approach, new insights into the interactions between these two biosynthetic pathways have been gained. Specifically, core fatty acid biosynthesis genes previously thought to be essential were found to be nonessential in strains harboring both pathways due to functional overlap between the two pathways. These results provide new routes to genetically optimize long-chain omega-3 polyunsaturated fatty acid biosynthesis in bacteria and reveal a possible ecological role for maintaining multiple pathways for lipid synthesis in a single bacterium.
Collapse
|
24
|
Velázquez-Sánchez C, Vences-Guzmán MÁ, Moreno S, Tinoco-Valencia R, Espín G, Guzmán J, Sahonero-Canavesi DX, Sohlenkamp C, Segura D. PsrA positively regulates the unsaturated fatty acid synthesis operon fabAB in Azotobacter vinelandii. Microbiol Res 2021; 249:126775. [PMID: 33964629 DOI: 10.1016/j.micres.2021.126775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/12/2021] [Accepted: 04/27/2021] [Indexed: 10/21/2022]
Abstract
In Pseudomonas spp. PsrA, a transcriptional activator of the rpoS gene, regulates fatty acid catabolism by repressing the fadBA5 β-oxidation operon. In Azotobacter vinelandii, a soil bacterium closely related to Pseudomonas species, PsrA is also an activator of rpoS expression, although its participation in the regulation of lipid metabolism has not been analyzed. In this work we found that inactivation of psrA had no effect on the expression of β-oxidation genes in this bacterium, but instead decreased expression of the unsaturated fatty acid biosynthetic operon fabAB (3-hydroxydecanoyl-ACP dehydratase/isomerase and 3-ketoacyl-ACP synthase I). This inactivation also reduced the unsaturated fatty acid content, as revealed by the thin-layer chromatographic analysis, and confirmed by gas chromatography; notably, there was also a lower content of cyclopropane fatty acids, which are synthesized from unsaturated fatty acids. The absence of PsrA has no effect on the growth rate, but showed loss of cell viability during long-term growth, in accordance with the role of these unsaturated and cyclopropane fatty acids in the protection of membranes. Finally, an electrophoretic mobility shift assay revealed specific binding of PsrA to the fabA promoter region, where a putative binding site for this regulator was located. Taken together, our data show that PsrA plays an important role in the regulation of unsaturated fatty acids metabolism in A. vinelandii by positively regulating fabAB.
Collapse
Affiliation(s)
- Claudia Velázquez-Sánchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | | | - Soledad Moreno
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Raunel Tinoco-Valencia
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Guadalupe Espín
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Josefina Guzmán
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | | | - Christian Sohlenkamp
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Daniel Segura
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
| |
Collapse
|
25
|
Li YQ, Chai YH, Wang XS, Huang LY, Luo XM, Qiu C, Liu QH, Guan XY. Bacterial community in saline farmland soil on the Tibetan plateau: responding to salinization while resisting extreme environments. BMC Microbiol 2021; 21:119. [PMID: 33874905 PMCID: PMC8056723 DOI: 10.1186/s12866-021-02190-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/05/2021] [Indexed: 11/23/2022] Open
Abstract
Background Salinization damages the health of soil systems and reduces crop yields. Responses of microbial communities to salinized soils and their functional maintenance under high salt stress are valuable scientific problems. Meanwhile, the microbial community of the salinized soil in the plateau environment is less understood. Here, we applied metagenomics technology to reveal the structure and function of microorganisms in salinized soil of the Tibetan Plateau. Results The diversity of composition and function of microbial community in saline soil have changed significantly. The abundances of chemoautotrophic and acidophilic bacteria comprising Rhodanobacter, Acidobacterium, Candidatus Nitrosotalea, and Candidatus Koribacter were significantly higher in saline soil. The potential degradation of organic carbon in the saline soil, as well as the production of NO and N2O via denitrification, and the production of sulfate by sulfur oxidation were significantly higher than the non-saline soil. Both types of soils were rich in genes encoding resistance to environmental stresses (i.e., cold, ultraviolet light, and hypoxia in Tibetan Plateau). The resistance of the soil microbial communities to the saline environment is based on the absorption of K+ as the main mechanism, with cross-protection proteins and absorption buffer molecules as auxiliary mechanisms in our study area. Network analysis showed that functional group comprising chemoautotrophic and acidophilic bacteria had significant positive correlations with electrical conductivity and total sulfur, and significant negative correlations with the total organic carbon, pH, and available nitrogen. The soil moisture, pH, and electrical conductivity are likely to affect the bacterial carbon, nitrogen, and sulfur cycles. Conclusions These results indicate that the specific environment of the Tibetan Plateau and salinization jointly shape the structure and function of the soil bacterial community, and that the bacterial communities respond to complex and harsh living conditions. In addition, environmental feedback probably exacerbates greenhouse gas emissions and accelerates the reduction in the soil pH. This study will provide insights into the microbial responses to soil salinization and the potential ecological risks in the special plateau environment. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02190-6.
Collapse
Affiliation(s)
- Yi Qiang Li
- School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Ying Hui Chai
- School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China.,Laboratory division, Eighth Medical Center of Chinese People's Liberation Army General Hospital, Beijing, 100000, People's Republic of China
| | - Xu Sheng Wang
- School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Li Ying Huang
- Institute of Agricultural Quality Standards and Testing, Tibet Academy of Agriculture and Animal Husbandry Sciences, Lhasa, 850000, China
| | - Xi Ming Luo
- School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China.,Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Cheng Qiu
- Institute of Agricultural Quality Standards and Testing, Tibet Academy of Agriculture and Animal Husbandry Sciences, Lhasa, 850000, China
| | - Qing Hai Liu
- Institute of Agricultural Quality Standards and Testing, Tibet Academy of Agriculture and Animal Husbandry Sciences, Lhasa, 850000, China
| | - Xiang Yu Guan
- School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China. .,Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, China.
| |
Collapse
|
26
|
Effects of a Δ-9-fatty acid desaturase and a cyclopropane-fatty acid synthase from the novel psychrophile Pseudomonas sp. B14-6 on bacterial membrane properties. J Ind Microbiol Biotechnol 2020; 47:1045-1057. [PMID: 33259029 DOI: 10.1007/s10295-020-02333-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/17/2020] [Indexed: 10/22/2022]
Abstract
Psychrophilic bacteria, living at low and mild temperatures, can contribute significantly to our understanding of microbial responses to temperature, markedly occurring in the bacterial membrane. Here, a newly isolated strain, Pseudomonas sp. B14-6, was found to dynamically change its unsaturated fatty acid and cyclic fatty acid content depending on temperature which was revealed by phospholipid fatty acid (PLFA) analysis. Genome sequencing yielded the sequences of the genes Δ-9-fatty acid desaturase (desA) and cyclopropane-fatty acid-acyl-phospholipid synthase (cfa). Overexpression of desA in Escherichia coli led to an increase in the levels of unsaturated fatty acids, resulting in decreased membrane hydrophobicity and increased fluidity. Cfa proteins from different species were all found to promote bacterial growth, despite their sequence diversity. In conclusion, PLFA analysis and genome sequencing unraveled the temperature-related behavior of Pseudomonas sp. B14-6 and the functions of two membrane-related enzymes. Our results shed new light on temperature-dependent microbial behaviors and might allow to predict the consequences of global warming on microbial communities.
Collapse
|
27
|
Wang Y, Wang F, Zhang X, Cen C, Fu L. Transcription factors FabR and FadR regulate cold adaptability and spoilage potential of Shewanella baltica. Int J Food Microbiol 2020; 331:108693. [PMID: 32535524 DOI: 10.1016/j.ijfoodmicro.2020.108693] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/30/2020] [Accepted: 05/26/2020] [Indexed: 10/24/2022]
Abstract
Shewanella baltica is the specific spoilage microorganism of Pseudosciaena crocea during low-temperature storage. Exploring the correlation between cold adaptability and spoilage potential may provide a new perspective for prolonging shelf life of aquatic products. In the present study, we investigated the synthesis pathway of unsaturated fatty acid (UFA) responsible for regulating cold adaptability in Shewanella baltica and its effect on spoilage potential. FabR and FadR, as key regulators of membrane unsaturated fatty acids synthesis pathway, were identified in S. baltica. FabR was significantly down-regulated at 4 °C compared to at 30 °C, yet FadR displayed the opposite results. By overexpressing fabR and fadR genes at 4 °C, we found that FabR and FadR had negative and positive effects on UFA content and membrane fluidity as well as spoilage potential, respectively. These data indicated that FabR and FadR functioned collectively to increase the membrane fluidity for better cold adaptability at low temperature, resulting in the maintenance of spoilage potential of S. baltica.
Collapse
Affiliation(s)
- Yanbo Wang
- Key Laboratory for Food Microbial Technology of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China; Zhejiang Engineering Institute of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Feifei Wang
- Key Laboratory for Food Microbial Technology of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Xiaoshuang Zhang
- Key Laboratory for Food Microbial Technology of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Congnan Cen
- Key Laboratory for Food Microbial Technology of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China
| | - Linglin Fu
- Key Laboratory for Food Microbial Technology of Zhejiang Province, School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China; Zhejiang Engineering Institute of Food Quality and Safety, Zhejiang Gongshang University, Hangzhou 310018, China.
| |
Collapse
|
28
|
Pan X, Fan Z, Chen L, Liu C, Bai F, Wei Y, Tian Z, Dong Y, Shi J, Chen H, Jin Y, Cheng Z, Jin S, Lin J, Wu W. PvrA is a novel regulator that contributes to Pseudomonas aeruginosa pathogenesis by controlling bacterial utilization of long chain fatty acids. Nucleic Acids Res 2020; 48:5967-5985. [PMID: 32406921 PMCID: PMC7293031 DOI: 10.1093/nar/gkaa377] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 12/19/2022] Open
Abstract
During infection of a host, Pseudomonas aeruginosa orchestrates global gene expression to adapt to the host environment and counter the immune attacks. P. aeruginosa harbours hundreds of regulatory genes that play essential roles in controlling gene expression. However, their contributions to the bacterial pathogenesis remain largely unknown. In this study, we analysed the transcriptomic profile of P. aeruginosa cells isolated from lungs of infected mice and examined the roles of upregulated regulatory genes in bacterial virulence. Mutation of a novel regulatory gene pvrA (PA2957) attenuated the bacterial virulence in an acute pneumonia model. Chromatin immunoprecipitation (ChIP)-Seq and genetic analyses revealed that PvrA directly regulates genes involved in phosphatidylcholine utilization and fatty acid catabolism. Mutation of the pvrA resulted in defective bacterial growth when phosphatidylcholine or palmitic acid was used as the sole carbon source. We further demonstrated that palmitoyl coenzyme A is a ligand for the PvrA, enhancing the binding affinity of PvrA to its target promoters. An arginine residue at position 136 was found to be essential for PvrA to bind palmitoyl coenzyme A. Overall, our results revealed a novel regulatory pathway that controls genes involved in phosphatidylcholine and fatty acid utilization and contributes to the bacterial virulence.
Collapse
Affiliation(s)
- Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zheng Fan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Lei Chen
- Department of Plant Biology and Ecology, College of Life Science Nankai University, Tianjin 300071 China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yu Wei
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin 300071, China
| | - Zhenyang Tian
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yuanyuan Dong
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Hao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shouguang Jin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jianping Lin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin 300071, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| |
Collapse
|
29
|
Allemann MN, Allen EE. Genetic regulation of the bacterial omega-3 polyunsaturated fatty acid biosynthesis pathway. J Bacteriol 2020; 202:JB.00050-20. [PMID: 32513681 PMCID: PMC8404712 DOI: 10.1128/jb.00050-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/28/2020] [Indexed: 02/07/2023] Open
Abstract
A characteristic among many marine Gammaproteobacteria is the biosynthesis and incorporation of omega-3 polyunsaturated fatty acids into membrane phospholipids. The biosynthesis of eicosapentaenoic (EPA) and/or docosahexaenoic (DHA) acids is mediated by a polyketide/fatty acid synthase mechanism encoded by a set of five genes, pfaABCDE. This unique fatty acid synthesis pathway co-exists with the principal type II dissociated fatty acid synthesis pathway, which is responsible for the biosynthesis of core saturated, monounsaturated, and hydroxylated fatty acids used in phospholipid and lipid A biosynthesis. In this work, a genetic approach was undertaken to elucidate genetic regulation of the pfa genes in the model marine bacterium Photobacterium profundum SS9. Using a reporter gene fusion, we showed that expression of the pfa operon is down regulated in response to exogenous fatty acids, particularly long chain monounsaturated fatty acids. This regulation occurs independently of the canonical fatty acid regulators, FabR and FadR, present in P. profundum SS9. Transposon mutagenesis and screening of a library of mutants identified a novel transcriptional regulator, which we have designated pfaF, to be responsible for the observed regulation of the pfa operon in P. profundum SS9. Gel mobility shift and DNase I footprinting assays confirmed that PfaF binds the pfaA promoter and identified the PfaF binding site.Importance The production of long-chain omega-3 polyunsaturated fatty acids (PUFA) by marine Gammaproteobacteria, particularly those from deep-sea environments, has been known for decades. These unique fatty acids are produced by a polyketide-type mechanism and subsequently incorporated into the phospholipid membrane. While much research has focused on the biosynthesis genes, their products and the phylogenetic distribution of these gene clusters, no prior studies have detailed the genetic regulation of this pathway. This study describes how this pathway is regulated under various culture conditions and has identified and characterized a fatty acid responsive transcriptional regulator specific to PUFA biosynthesis.
Collapse
Affiliation(s)
- Marco N Allemann
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA USA
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA USA
| | - Eric E Allen
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA USA
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA USA
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA USA
| |
Collapse
|
30
|
Martínez-Carranza E, García-Reyes S, González-Valdez A, Soberón-Chávez G. Tracking the genome of four Pseudomonas aeruginosa isolates that have a defective Las quorum-sensing system, but are still virulent. Access Microbiol 2020; 2:acmi000132. [PMID: 32974595 PMCID: PMC7497837 DOI: 10.1099/acmi.0.000132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/14/2020] [Indexed: 01/24/2023] Open
Abstract
In this work we analysed the whole genome extended multilocus sequence typing (wgMLST) of four Pseudomonas aeruginosa strains that are characterized by being virulent despite having a defective Las quorum-sensing (QS) system, and compare them with the wgMLST of the PAO1 and PA14 type strains. This comparison was done to determine whether there was a genomic characteristic that was common to the strains with an atypical QS response. The analysed strains include two environmental isolates (ID 4365 isolated from the Indian Ocean, and M66 isolated from the Churince water system in Cuatro Ciénegas Coahuila, México), one veterinary isolate (strain 148 isolated from the stomach of a dolphin) and a clinical strain (INP43 that is a cystic fibrosis pediatric isolate). We determine that the six analysed strains have a core genome of 4689 loci that was used to construct a wgMLST-phylogeny tree. Using the cano-wgMLST_BacCompare software we found that there was no common genomic characteristic to the strains with an atypical QS-response and we identify ten loci that are highly discriminatory of the six strains’ phylogeny so that their MLST can reconstruct the wgMLST-phylogeny tree of these strains. We discuss here the nature of these ten highly discriminatory genes in the context of P. aeruginosa virulence and evolution.
Collapse
Affiliation(s)
- Enrique Martínez-Carranza
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo. Postal 70228, C. P. 04510, CDMX, México
| | - Selene García-Reyes
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo. Postal 70228, C. P. 04510, CDMX, México
| | - Abigail González-Valdez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo. Postal 70228, C. P. 04510, CDMX, México
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apdo. Postal 70228, C. P. 04510, CDMX, México
| |
Collapse
|
31
|
Ha J, Kim S, Lee J, Lee H, Choi Y, Oh H, Yoon Y, Choi KH. The role of Pseudomonas aeruginosa DesB in pathogen-host interaction. Int Microbiol 2020; 23:549-555. [PMID: 32323095 DOI: 10.1007/s10123-020-00130-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/19/2020] [Accepted: 04/13/2020] [Indexed: 11/25/2022]
Abstract
Pseudomonas aeruginosa, commonly found in environments, can cause chronic lung disease in immunocompromised patients. In previous study, an aerobic desaturase (DesB) in P. aeruginosa exerted considerable effects on virulence factor production. The objective of this study was to analyze the role of DesB on the virulence traits of P. aeruginosa in the host. For the in vitro experiments, cells and supernatants from wild-type (WT) P. aeruginosa and its desB mutant were collected. The diluted cells were added to the A549 cell monolayer in order to determine cell viability, invasion ability, and/or immune response. For the in vivo experiments, 6-week-old ICR mice were infected with 6-7 log CFU bacterial cells using endotracheal intubation. The ratio of lung weight to body weight and survival rate of each bacterial strain in the lung were measured. The histopathology of lung tissue was also studied. desB mutants exhibited lower cytotoxicity in A549 cells. In addition, more pro-inflammatory cytokines and chemokines were present in desB mutant-treated. In the lungs of mouse model, WT survived longer than desB mutant, and the WT migrated from the lung to the liver and spleen. The results suggest that P. aeruginosa DesB affects the pathogenicity of the organism in the host.
Collapse
Affiliation(s)
- Jimyeong Ha
- Risk Analysis Research Center, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Sejeong Kim
- Risk Analysis Research Center, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Jeeyeon Lee
- Department of Food and Nutrition, Dong-eui University, Busan, 47340, South Korea
| | - Heeyoung Lee
- Food Standard Research Center, Korea Food Research Institute, Wanju, Jeollabuk-do, 55365, South Korea
| | - Yukyung Choi
- Department of Food and Nutrition, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Hyemin Oh
- Department of Food and Nutrition, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Yohan Yoon
- Risk Analysis Research Center, Sookmyung Women's University, Seoul, 04310, South Korea
- Department of Food and Nutrition, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Kyoung-Hee Choi
- Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan, 54538, South Korea.
| |
Collapse
|
32
|
Liu J, Yu M, Chatnaparat T, Lee JH, Tian Y, Hu B, Zhao Y. Comparative transcriptomic analysis of global gene expression mediated by (p) ppGpp reveals common regulatory networks in Pseudomonas syringae. BMC Genomics 2020; 21:296. [PMID: 32272893 PMCID: PMC7146990 DOI: 10.1186/s12864-020-6701-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/25/2020] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Pseudomonas syringae is an important plant pathogen, which could adapt many different environmental conditions. Under the nutrient-limited and other stress conditions, P. syringae produces nucleotide signal molecules, i.e., guanosine tetra/pentaphosphate ((p)ppGpp), to globally regulate gene expression. Previous studies showed that (p) ppGpp played an important role in regulating virulence factors in P. syringae pv. tomato DC3000 (PstDC3000) and P. syringae pv. syringae B728a (PssB728a). Here we present a comparative transcriptomic analysis to uncover the overall effects of (p)ppGpp-mediated stringent response in P. syringae. RESULTS In this study, we investigated global gene expression profiles of PstDC3000 and PssB728a and their corresponding (p)ppGpp0 mutants in hrp-inducing minimal medium (HMM) using RNA-seq. A total of 1886 and 1562 differentially expressed genes (DEGs) were uncovered between the (p)ppGpp0 mutants and the wild-type in PstDC3000 and PssB728a, respectively. Comparative transcriptomics identified 1613 common DEGs, as well as 444 and 293 unique DEGs in PstDC3000 and PssB728a, respectively. Functional cluster analysis revealed that (p) ppGpp positively regulated a variety of virulence-associated genes, including type III secretion system (T3SS), type VI secretion system (T6SS), cell motility, cell division, and alginate biosynthesis, while negatively regulated multiple basic physiological processes, including DNA replication, RNA processes, nucleotide biosynthesis, fatty acid metabolism, ribosome protein biosynthesis, and amino acid metabolism in both PstDC3000 and PssB728a. Furthermore, (p) ppGpp had divergent effects on other processes in PstDC3000 and PssB728a, including phytotoxin, nitrogen regulation and general secretion pathway (GSP). CONCLUSION In this study, comparative transcriptomic analysis reveals common regulatory networks in both PstDC3000 and PssB728a mediated by (p) ppGpp in HMM. In both P. syringae systems, (p) ppGpp re-allocate cellular resources by suppressing multiple basic physiological activities and enhancing virulence gene expression, suggesting a balance between growth, survival and virulence. Our research is important in that due to similar global gene expression mediated by (p) ppGpp in both PstDC3000 and PssB728a, it is reasonable to propose that (p) ppGpp could be used as a target to develop novel control measures to fight against important plant bacterial diseases.
Collapse
Affiliation(s)
- Jun Liu
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing, 210095, P. R. China.,Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr., Urbana, IL, 61801, USA
| | - Menghao Yu
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr., Urbana, IL, 61801, USA
| | - Tiyakhon Chatnaparat
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr., Urbana, IL, 61801, USA
| | - Jae Hoon Lee
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr., Urbana, IL, 61801, USA
| | - Yanli Tian
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Baishi Hu
- College of Plant Protection, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, Nanjing, 210095, P. R. China.
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, 1201 W. Gregory Dr., Urbana, IL, 61801, USA.
| |
Collapse
|
33
|
Shrestha P, Zhang Y, Chen WJ, Wong TY. Triclosan: antimicrobial mechanisms, antibiotics interactions, clinical applications, and human health. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, TOXICOLOGY AND CARCINOGENESIS 2020; 38:245-268. [PMID: 32955413 DOI: 10.1080/26896583.2020.1809286] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The large-scale applications of Triclosan in industrial and household products have created many health and environmental concerns. Despite the fears of its drug-resistance and other issues, Triclosan is still an effective drug against many infectious organisms. Knowing the cross-interactions of Triclosan with different antibiotics, bacteria, and humans can provide much-needed information for the risk assessment of this drug. We review the current understanding of the antimicrobial mechanisms of Triclosan, how microbes become resistant to Triclosan, and the synergistic and antagonistic effects of Triclosan with different antibiotics. Current literature on the clinical applications of Triclosan and its effect on fetus/child development are also summarized.
Collapse
Affiliation(s)
- Prabin Shrestha
- Biological Sciences Department, University of Memphis, Memphis, Tennessee, USA
| | | | - Wen-Jen Chen
- Biological Sciences Department, University of Memphis, Memphis, Tennessee, USA
| | - Tit-Yee Wong
- Biological Sciences Department, University of Memphis, Memphis, Tennessee, USA
| |
Collapse
|
34
|
Connors E, Soto-Dávila M, Hossain A, Vasquez I, Gnanagobal H, Santander J. Identification and validation of reliable Aeromonas salmonicida subspecies salmonicida reference genes for differential gene expression analyses. INFECTION GENETICS AND EVOLUTION 2019; 73:314-321. [DOI: 10.1016/j.meegid.2019.05.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/09/2019] [Accepted: 05/14/2019] [Indexed: 01/19/2023]
|
35
|
Le Sénéchal C, Crouzet M, Costaglioli P, Barthe C, Buré C, Vilain S. Phospholipid Content of Pseudomonas aeruginosa PAO1 Is Modulated by the Growth Phase Rather Than the Immobilization State. Lipids 2019; 54:519-529. [PMID: 31397925 DOI: 10.1002/lipd.12184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 11/11/2022]
Abstract
Biofilms have significance in medical, industrial, and environmental settings, and can cause important damage. As biofilms are tolerant to various stresses, including antibiotics, it is necessary to better understand their formation. For this reason, we characterized the phospholipidome of Pseudomonas aeruginosa, an opportunistic pathogen involved in numerous infections, during the first steps of the biofilm development. By a liquid chromatography-tandem mass spectrometry time-course analysis over a 24-h period, we compared the phospholipid (PL) composition of immobilized (attached) and planktonic (unattached) P. aeruginosa PAO1 cells. Our results showed that the PL content of P. aeruginosa PAO1 was mainly modulated by the incubation time, thus related to bacterial growth but also, more modestly, by the immobilization state. We observed that relative amounts of PL varied over time with two main profiles and that these profiles are correlated to its fatty acid composition, including the degree of unsaturation. A statistical analysis revealed that the PL contents of both attached and unattached PAO1 cells were significantly different mainly after 3 and 6 h of incubation and that the amounts of two PL presented a statistical difference between attached and unattached cells all along the 24-h period: PtdEtn 16:0_18:1 and PtdEtn 18:1_18:1.
Collapse
Affiliation(s)
| | - Marc Crouzet
- CBMN, University of Bordeaux, UMR 5248, F-33600, Pessac, France
| | | | | | | | | |
Collapse
|
36
|
Kim S, Ha J, Lee H, Lee S, Lee J, Choi Y, Oh H, Yoon Y, Choi KH. Role of Pseudomonas aeruginosa DesB in Adaptation to Osmotic Stress. J Food Prot 2019; 82:1278-1282. [PMID: 31298570 DOI: 10.4315/0362-028x.jfp-18-507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Proper membrane fluidity is maintained by adjusting the ratio of saturated fatty acids to unsaturated fatty acids (UFAs), and the control of membrane fluidity plays an important role in bacterial adaptation to stress. Adaptability to these stresses involves survival and colonization of bacteria, thus contributing to bacterial contamination in food. UFAs are synthesized by FabAB- and Des-mediated pathways in Pseudomonas aeruginosa. Therefore, in this study, the roles of UFA-synthesizing proteins of P. aeruginosa in resistance to stresses were examined. The growth and transcription levels of wild-type (WT) P. aeruginosa PAO1 and its mutants were compared. The growth of all strains was inhibited by exposure to 0.5 or 1.0 M sodium chloride, but it was not affected by oxidative or pH stress. In particular, growth was impaired more substantially in the desB mutant than in the WT strain and other mutants, suggesting that DesB has a role in response to salt stress. A comparative transcriptional analysis showed that genes involved in the synthesis of osmoprotectants (trehalose, N-acetylglutaminylglutamine amide, and hydrophilin) were highly expressed in WT P. aeruginosa in response to high salt, but they were rarely expressed in the desB mutant. Furthermore, decreases in osmoprotectant production by the desB mutant were partially complemented by the addition of betaine. These results indicate that P. aeruginosa DesB contributes to adaptation to high salinity by positively regulating the synthesis of osmoprotectants.
Collapse
Affiliation(s)
- Sejeong Kim
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Jimyeong Ha
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Heeyoung Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Soomin Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Jeeyeon Lee
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Yukyung Choi
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Hyemin Oh
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Yohan Yoon
- 1 Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, Korea
| | - Kyoung-Hee Choi
- 2 Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan 570-749, Korea
| |
Collapse
|
37
|
Shi Z. Methylome and Metabolome Analyses Reveal Adaptive Mechanisms in Geobacter sulfurreducens Grown on Different Terminal Electron Acceptors. J Proteome Res 2019; 18:1494-1502. [DOI: 10.1021/acs.jproteome.8b00763] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Zhenhua Shi
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| |
Collapse
|
38
|
Heredia RM, Lucchesi GI. Pseudomonas putida Δ9-fatty acid desaturase: Gene cloning, expression, and function in the cationic surfactants stress. J Basic Microbiol 2019; 59:525-534. [PMID: 30779369 DOI: 10.1002/jobm.201800595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/07/2019] [Accepted: 01/13/2019] [Indexed: 11/06/2022]
Abstract
Pseudomonas putida counteract the fluidizing effect of cationic surfactants decreasing the content of membrane unsaturated fatty acid (UFA). A Δ9-fatty acid desaturase gene (desA) from P. putida was isolated, cloned, and successfully expressed in Escherichia coli, a Δ9 desaturase deficient organism. desA consists of 1185 bp and codes for 394 amino acids. The deduced amino acid sequence reveals three histidine clusters and a hydropathy profile, typical of membrane-bound desaturases. Validating desA expression in E. coli cells, the amount of palmitoleic acid increased from 2.05 to 7.36%, with the concomitant increase in membrane fluidity (fluorescence polarization value decrease from 0.13 ± 0.03 to 0.09 ± 0.02). Also, when DesA activity was assayed in vivo, the percentage of UFA obtained from exogenous palmitic acid [1-14 C] increased 10-fold. In contrast, when cells expressing desA were exposed 15 min at sublethal concentration of cationic surfactants, the amount of UFA was 82% lower than that detected in cells non-exposed. Thus, the decrease in UFA content to counteract the fluidizing effect of cationic surfactants can be correlated with reduction of DesA activity.
Collapse
Affiliation(s)
- Romina M Heredia
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| | - Gloria I Lucchesi
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina
| |
Collapse
|
39
|
Zhang L, Ding L, He X, Ma H, Fu H, Wang J, Ren H. Effect of continuous and intermittent electric current on lignin wastewater treatment and microbial community structure in electro-microbial system. Sci Rep 2019; 9:805. [PMID: 30692563 PMCID: PMC6349836 DOI: 10.1038/s41598-018-34379-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/11/2018] [Indexed: 12/17/2022] Open
Abstract
In this study, complex structured soluble lignin wastewater was treated by electro-microbial system (EMS) using different direct current (DC) application modes (CR (continuous ON), IR12h (12 h-ON/12 h-OFF) and IR2h (2 h-ON/2 h-OFF)), and physiological characteristics and microbial communities were investigated. Results showed that CR, IR12h and IR2h had higher lignin removals, which were almost two times that of the control reactor (R0′, no current), and IR2h performed best and stably. Furthermore, IR2h exhibited the lowest ohmic resistance (Rs) of electrode biofilms, which could be explained by its higher abundance of electroactive bacteria. In the activated sludge of EMS, the concentration of dehydrogenase activity (DHA) and electronic transport system (ETS) in IR2h were the highest (1.48 and 1.28 times of R0′), which contributed to its high content of adenosine triphosphate (ATP). The viability of activated sludge was not affected by different DC application modes. Phospholipid fatty acids (PLFA) analysis indicated that IR2h had the maximum content of C15:1 anteiso A, C16:0 and C18:0; CR increased the content of C15:0 anteiso and decreased the content of saturated fatty acids. Genus-level results revealed that lignin-degrading bacteria, Pseudoxanthomonas and Mycobacterium, could be enriched in IR2h and CR, respectively.
Collapse
Affiliation(s)
- Lulu Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Xuemeng He
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Haijun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Huimin Fu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Jinfeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
| |
Collapse
|
40
|
Lefebvre C, Boulon R, Ducoux M, Gavalda S, Laval F, Jamet S, Eynard N, Lemassu A, Cam K, Bousquet MP, Bardou F, Burlet-Schiltz O, Daffé M, Quémard A. HadD, a novel fatty acid synthase type II protein, is essential for alpha- and epoxy-mycolic acid biosynthesis and mycobacterial fitness. Sci Rep 2018; 8:6034. [PMID: 29662082 PMCID: PMC5902629 DOI: 10.1038/s41598-018-24380-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Mycolic acids (MAs) have a strategic location within the mycobacterial envelope, deeply influencing its architecture and permeability, and play a determinant role in the pathogenicity of mycobacteria. The fatty acid synthase type II (FAS-II) multienzyme system is involved in their biosynthesis. A combination of pull-downs and proteomics analyses led to the discovery of a mycobacterial protein, HadD, displaying highly specific interactions with the dehydratase HadAB of FAS-II. In vitro activity assays and homology modeling showed that HadD is, like HadAB, a hot dog folded (R)-specific hydratase/dehydratase. A hadD knockout mutant of Mycobacterium smegmatis produced only the medium-size alpha’-MAs. Data strongly suggest that HadD is involved in building the third meromycolic segment during the late FAS-II elongation cycles, leading to the synthesis of the full-size alpha- and epoxy-MAs. The change in the envelope composition induced by hadD inactivation strongly altered the bacterial fitness and capacities to aggregate, assemble into colonies or biofilms and spread by sliding motility, and conferred a hypersensitivity to the firstline antimycobacterial drug rifampicin. This showed that the cell surface properties and the envelope integrity were greatly affected. With the alarmingly increasing case number of nontuberculous mycobacterial diseases, HadD appears as an attractive target for drug development.
Collapse
Affiliation(s)
- Cyril Lefebvre
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Richard Boulon
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Manuelle Ducoux
- Département Biologie Structurale & Biophysique, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Sabine Gavalda
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Françoise Laval
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Stevie Jamet
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Nathalie Eynard
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Anne Lemassu
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Kaymeuang Cam
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Marie-Pierre Bousquet
- Département Biologie Structurale & Biophysique, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Fabienne Bardou
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Odile Burlet-Schiltz
- Département Biologie Structurale & Biophysique, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Mamadou Daffé
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France
| | - Annaïk Quémard
- Département Tuberculose & Biologie des Infections, Institut de Pharmacologie et de Biologie Structurale, UMR5089, Université de Toulouse, CNRS, UPS, 31077, Toulouse Cedex 04, France.
| |
Collapse
|
41
|
Gao R, Li D, Lin Y, Lin J, Xia X, Wang H, Bi L, Zhu J, Hassan B, Wang S, Feng Y. Structural and Functional Characterization of the FadR Regulatory Protein from Vibrio alginolyticus. Front Cell Infect Microbiol 2017; 7:513. [PMID: 29312893 PMCID: PMC5733061 DOI: 10.3389/fcimb.2017.00513] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 11/29/2017] [Indexed: 02/03/2023] Open
Abstract
The structure of Vibrio cholerae FadR (VcFadR) complexed with the ligand oleoyl-CoA suggests an additional ligand-binding site. However, the fatty acid metabolism and its regulation is poorly addressed in Vibrio alginolyticus, a species closely-related to V. cholerae. Here, we show crystal structures of V. alginolyticus FadR (ValFadR) alone and its complex with the palmitoyl-CoA, a long-chain fatty acyl ligand different from the oleoyl-CoA occupied by VcFadR. Structural comparison indicates that both VcFadR and ValFadR consistently have an additional ligand-binding site (called site 2), which leads to more dramatic conformational-change of DNA-binding domain than that of the E. coli FadR (EcFadR). Isothermal titration calorimetry (ITC) analyses defines that the ligand-binding pattern of ValFadR (2:1) is distinct from that of EcFadR (1:1). Together with surface plasmon resonance (SPR), electrophoresis mobility shift assay (EMSA) demonstrates that ValFadR binds fabA, an important gene of unsaturated fatty acid (UFA) synthesis. The removal of fadR from V. cholerae attenuates fabA transcription and results in the unbalance of UFA/SFA incorporated into membrane phospholipids. Genetic complementation of the mutant version of fadR (Δ42, 136-177) lacking site 2 cannot restore the defective phenotypes of ΔfadR while the wild-type fadR gene and addition of exogenous oleate can restore them. Mice experiments reveals that VcFadR and its site 2 have roles in bacterial colonizing. Together, the results might represent an additional example that illustrates the Vibrio FadR-mediated lipid regulation and its role in pathogenesis.
Collapse
Affiliation(s)
- Rongsui Gao
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China
| | - Defeng Li
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yuan Lin
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jingxia Lin
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyun Xia
- Department of Microbiology, Nanjing Agricultural University, Nanjing, China
| | - Hui Wang
- Department of Microbiology, Nanjing Agricultural University, Nanjing, China
| | - Lijun Bi
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jun Zhu
- Department of Microbiology, Nanjing Agricultural University, Nanjing, China.,Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Bachar Hassan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Shihua Wang
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Youjun Feng
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
42
|
Adaptive evolution by spontaneous domain fusion and protein relocalization. Nat Ecol Evol 2017; 1:1562-1568. [PMID: 29185504 DOI: 10.1038/s41559-017-0283-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 07/18/2017] [Indexed: 11/08/2022]
Abstract
Knowledge of adaptive processes encompasses understanding the emergence of new genes. Computational analyses of genomes suggest that new genes can arise by domain swapping; however, empirical evidence has been lacking. Here we describe a set of nine independent deletion mutations that arose during selection experiments with the bacterium Pseudomonas fluorescens in which the membrane-spanning domain of a fatty acid desaturase became translationally fused to a cytosolic di-guanylate cyclase, generating an adaptive 'wrinkly spreader' phenotype. Detailed genetic analysis of one gene fusion shows that the mutant phenotype is caused by relocalization of the di-guanylate cyclase domain to the cell membrane. The relative ease by which this new gene arose, along with its functional and regulatory effects, provides a glimpse of mutational events and their consequences that are likely to have a role in the evolution of new genes.
Collapse
|
43
|
Di Capua CB, Doprado M, Belardinelli JM, Morbidoni HR. Complete auxotrophy for unsaturated fatty acids requires deletion of two sets of genes in Mycobacterium smegmatis. Mol Microbiol 2017; 106:93-108. [PMID: 28762586 DOI: 10.1111/mmi.13753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2017] [Indexed: 11/29/2022]
Abstract
The synthesis of unsaturated fatty acids in Mycobacterium smegmatis is poorly characterized. Bioinformatic analysis revealed four putative fatty acid desaturases in its genome, one of which, MSMEG_1886, is highly homologous to desA3, the only palmitoyl/stearoyl desaturase present in the Mycobacterium tuberculosis genome. A MSMEG_1886 deletion mutant was partially auxotrophic for oleic acid and viable at 37°C and 25°C, although with a long lag phase in liquid medium. Fatty acid analysis suggested that MSMEG_1886 is a palmitoyl/stearoyl desaturase, as the synthesis of palmitoleic acid was abrogated, while oleic acid contents dropped by half in the mutant. Deletion of the operon MSMEG_1741-1743 (highly homologous to a Pseudomonas aeruginosa acyl-CoA desaturase) had little effect on growth of the parental strain; however the double mutant MSMEG_1886-MSMEG_1741-1743 strictly required oleic acid for growth. The ΔMSMEG_1886-ΔMSMEG_1741 double mutant was able to grow (poorly but better than the ΔMSMEG_1886 single mutant) in solid and liquid media devoid of oleic acid, suggesting a repressor role for ΔMSMEG_1741. Fatty acid analysis of the described mutants suggested that MSMEG_1742-43 desaturates C18:0 and C24:0 fatty acids. Thus, although the M. smegmatis desA3 homologue is the major player in unsaturated fatty acid synthesis, a second set of genes is also involved.
Collapse
Affiliation(s)
- Cecilia B Di Capua
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Mariana Doprado
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Juan Manuel Belardinelli
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Héctor R Morbidoni
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| |
Collapse
|
44
|
Hingston P, Chen J, Allen K, Truelstrup Hansen L, Wang S. Strand specific RNA-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in Listeria monocytogenes. PLoS One 2017; 12:e0180123. [PMID: 28662112 PMCID: PMC5491136 DOI: 10.1371/journal.pone.0180123] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/11/2017] [Indexed: 11/19/2022] Open
Abstract
The human pathogen Listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. Increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. This study utilized strand-specific RNA sequencing and whole cell fatty acid (FA) profiling to characterize the bacterium's cold stress response. RNA and FAs were extracted from a cold-tolerant strain at five time points between early lag phase and late stationary-phase, both at 4°C and 20°C. Overall, more genes (1.3×) were suppressed than induced at 4°C. Late stationary-phase cells exhibited the greatest number (n = 1,431) and magnitude (>1,000-fold) of differentially expressed genes (>2-fold, p<0.05) in response to cold. A core set of 22 genes was upregulated at all growth phases, including nine genes required for branched-chain fatty acid (BCFA) synthesis, the osmolyte transporter genes opuCBCD, and the internalin A and D genes. Genes suppressed at 4°C were largely associated with cobalamin (B12) biosynthesis or the production/export of cell wall components. Antisense transcription accounted for up to 1.6% of total mapped reads with higher levels (2.5×) observed at 4°C than 20°C. The greatest number of upregulated antisense transcripts at 4°C occurred in early lag phase, however, at both temperatures, antisense expression levels were highest in late stationary-phase cells. Cold-induced FA membrane changes included a 15% increase in the proportion of BCFAs and a 15% transient increase in unsaturated FAs between lag and exponential phase. These increases probably reduced the membrane phase transition temperature until optimal levels of BCFAs could be produced. Collectively, this research provides new information regarding cold-induced membrane composition changes in L. monocytogenes, the growth-phase dependency of its cold-stress regulon, and the active roles of antisense transcripts in regulating its cold stress response.
Collapse
Affiliation(s)
- Patricia Hingston
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessica Chen
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Kevin Allen
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Siyun Wang
- Department of Food, Nutrition, and Health, The University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
45
|
Garba L, Ali MSM, Oslan SN, Rahman RNZRA. Heterologous Expression of PA8FAD9 and Functional Characterization of a Δ9-Fatty Acid Desaturase from a Cold-Tolerant Pseudomonas sp. A8. Mol Biotechnol 2017; 58:718-728. [PMID: 27629791 DOI: 10.1007/s12033-016-9971-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Fatty acid desaturase enzymes are capable of inserting double bonds between carbon atoms of saturated fatty acyl-chains to produce unsaturated fatty acids. A gene coding for a putative Δ9-fatty acid desaturase-like protein was isolated from a cold-tolerant Pseudomonas sp. A8, cloned and heterologously expressed in Escherichia coli. The gene named as PA8FAD9 has an open reading frame of 1185 bp and codes for 394 amino acids with a predicted molecular weight of 45 kDa. The enzyme showed high Δ9-fatty acid desaturase-like protein activity and increased overall levels of cellular unsaturated fatty acids in the recombinant E. coli cells upon expression at different temperatures. The results showed that the ratio of palmitoleic to palmitic acid in the recombinant E. coli cells increased by more than twice the amount observed in the control cells at 20 °C using 0.4 mM IPTG. GCMS analysis confirmed the ability of this enzyme to convert exogenous stearic acid to oleic acid incorporated into the recombinant E. coli membrane phospholipids. It may be concluded that the PA8FAD9 gene from Pseudomonas sp. A8 codes for a putative Δ9-fatty acid desaturase protein actively expressed in E. coli under the influence of temperature and an inducer.
Collapse
Affiliation(s)
- Lawal Garba
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia.,Department of Microbiology, Faculty of Science, Gombe State University, Tudun Wada Gombe, P.M.B 127, Gombe State, Nigeria
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia.,Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Siti Nurbaya Oslan
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia.,Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia
| | - Raja Noor Zaliha Raja Abdul Rahman
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia. .,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia.
| |
Collapse
|
46
|
Bartell JA, Blazier AS, Yen P, Thøgersen JC, Jelsbak L, Goldberg JB, Papin JA. Reconstruction of the metabolic network of Pseudomonas aeruginosa to interrogate virulence factor synthesis. Nat Commun 2017; 8:14631. [PMID: 28266498 PMCID: PMC5344303 DOI: 10.1038/ncomms14631] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 01/18/2017] [Indexed: 01/13/2023] Open
Abstract
Virulence-linked pathways in opportunistic pathogens are putative therapeutic targets that may be associated with less potential for resistance than targets in growth-essential pathways. However, efficacy of virulence-linked targets may be affected by the contribution of virulence-related genes to metabolism. We evaluate the complex interrelationships between growth and virulence-linked pathways using a genome-scale metabolic network reconstruction of Pseudomonas aeruginosa strain PA14 and an updated, expanded reconstruction of P. aeruginosa strain PAO1. The PA14 reconstruction accounts for the activity of 112 virulence-linked genes and virulence factor synthesis pathways that produce 17 unique compounds. We integrate eight published genome-scale mutant screens to validate gene essentiality predictions in rich media, contextualize intra-screen discrepancies and evaluate virulence-linked gene distribution across essentiality datasets. Computational screening further elucidates interconnectivity between inhibition of virulence factor synthesis and growth. Successful validation of selected gene perturbations using PA14 transposon mutants demonstrates the utility of model-driven screening of therapeutic targets.
Collapse
Affiliation(s)
- Jennifer A. Bartell
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2970 Hørsholm, Denmark
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Anna S. Blazier
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Phillip Yen
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Juliane C. Thøgersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Lars Jelsbak
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Joanna B. Goldberg
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Children's Healthcare of Atlanta, Atlanta, Georgia 30322, USA
- Emory+Children's Center for Cystic Fibrosis Research, Emory University and Children's Healthcare of Atlanta, Atlanta, Georgia 30322, USA
| | - Jason A. Papin
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA
| |
Collapse
|
47
|
Demidenko A, Akberdin IR, Allemann M, Allen EE, Kalyuzhnaya MG. Fatty Acid Biosynthesis Pathways in Methylomicrobium buryatense 5G(B1). Front Microbiol 2017; 7:2167. [PMID: 28119683 PMCID: PMC5222806 DOI: 10.3389/fmicb.2016.02167] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/23/2016] [Indexed: 01/02/2023] Open
Abstract
Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1). Most of the genes homologous to typical Type II fatty acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of fatty acid transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for fatty acid biosynthesis regulation, farE, was identified and studied. Its deletion resulted in drastic changes to the fatty acid profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE-knockout mutants and farE-overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. The gene expression and fatty acid profiles of the different farE-strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph.
Collapse
Affiliation(s)
- Aleksandr Demidenko
- Department of Biology, San Diego State University, Campanile DriveSan Diego, CA, USA; Scripps Institution of Oceanography, University of California San Diego, Gilman DriveLa Jolla, CA, USA
| | - Ilya R Akberdin
- Department of Biology, San Diego State University, Campanile Drive San Diego, CA, USA
| | - Marco Allemann
- Scripps Institution of Oceanography, University of California San Diego, Gilman Drive La Jolla, CA, USA
| | - Eric E Allen
- Scripps Institution of Oceanography, University of California San Diego, Gilman Drive La Jolla, CA, USA
| | - Marina G Kalyuzhnaya
- Department of Biology, San Diego State University, Campanile Drive San Diego, CA, USA
| |
Collapse
|
48
|
Albanesi D, de Mendoza D. FapR: From Control of Membrane Lipid Homeostasis to a Biotechnological Tool. Front Mol Biosci 2016; 3:64. [PMID: 27766255 PMCID: PMC5052256 DOI: 10.3389/fmolb.2016.00064] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/21/2016] [Indexed: 01/22/2023] Open
Abstract
Phospholipids and fatty acids are not only one of the major components of cell membranes but also important metabolic intermediates in bacteria. Since the fatty acid biosynthetic pathway is essential and energetically expensive, organisms have developed a diversity of homeostatic mechanisms to fine-tune the concentration of lipids at particular levels. FapR is the first global regulator of lipid synthesis discovered in bacteria and is largely conserved in Gram-positive organisms including important human pathogens, such as Staphylococcus aureus, Bacillus anthracis, and Listeria monocytogenes. FapR is a transcription factor that negatively controls the expression of several genes of the fatty acid and phospholipid biosynthesis and was first identified in Bacillus subtilis. This review focuses on the genetic, biochemical and structural advances that led to a detailed understanding of lipid homeostasis control by FapR providing unique opportunities to learn how Gram-positive bacteria monitor the status of fatty acid biosynthesis and adjust the lipid synthesis accordingly. Furthermore, we also cover the potential of the FapR system as a target for new drugs against Gram-positive bacteria as well as its recent biotechnological applications in diverse organisms.
Collapse
Affiliation(s)
- Daniela Albanesi
- Laboratorio de Fisiología Microbiana, Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario Rosario, Argentina
| | - Diego de Mendoza
- Laboratorio de Fisiología Microbiana, Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Rosario Rosario, Argentina
| |
Collapse
|
49
|
Fozo EM, Rucks EA. The Making and Taking of Lipids: The Role of Bacterial Lipid Synthesis and the Harnessing of Host Lipids in Bacterial Pathogenesis. Adv Microb Physiol 2016; 69:51-155. [PMID: 27720012 DOI: 10.1016/bs.ampbs.2016.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In order to survive environmental stressors, including those induced by growth in the human host, bacterial pathogens will adjust their membrane physiology accordingly. These physiological changes also include the use of host-derived lipids to alter their own membranes and feed central metabolic pathways. Within the host, the pathogen is exposed to many stressful stimuli. A resulting adaptation is for pathogens to scavenge the host environment for readily available lipid sources. The pathogen takes advantage of these host-derived lipids to increase or decrease the rigidity of their own membranes, to provide themselves with valuable precursors to feed central metabolic pathways, or to impact host signalling and processes. Within, we review the diverse mechanisms that both extracellular and intracellular pathogens employ to alter their own membranes as well as their use of host-derived lipids in membrane synthesis and modification, in order to increase survival and perpetuate disease within the human host. Furthermore, we discuss how pathogen employed mechanistic utilization of host-derived lipids allows for their persistence, survival and potentiation of disease. A more thorough understanding of all of these mechanisms will have direct consequences for the development of new therapeutics, and specifically, therapeutics that target pathogens, while preserving normal flora.
Collapse
Affiliation(s)
- E M Fozo
- University of Tennessee, Knoxville, TN, United States.
| | - E A Rucks
- Sanford School of Medicine, University of South Dakota, Vermillion, SD, United States.
| |
Collapse
|
50
|
Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium. Int J Mol Sci 2016; 17:ijms17081374. [PMID: 27556460 PMCID: PMC5000769 DOI: 10.3390/ijms17081374] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/10/2016] [Accepted: 08/12/2016] [Indexed: 11/17/2022] Open
Abstract
Salmonella typhimurium cells were subjected to pulsed electric field (PEF) treatment at 25 kV/cm for 0–4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi), possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression), which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids). In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC) indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms.
Collapse
|