1
|
Heffernan JR, Wildenthal JA, Tran H, Katumba GL, McCoy WH, Henderson JP. Yersiniabactin is a quorum-sensing autoinducer and siderophore in uropathogenic Escherichia coli. mBio 2024; 15:e0027723. [PMID: 38236035 PMCID: PMC10865836 DOI: 10.1128/mbio.00277-23] [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: 02/08/2023] [Accepted: 12/07/2023] [Indexed: 01/19/2024] Open
Abstract
Siderophores are secreted ferric ion chelators used to obtain iron in nutrient-limited environmental niches, including human hosts. While all Escherichia coli express the enterobactin (Ent) siderophore system, isolates from patients with urinary tract infections additionally express the genetically distinct yersiniabactin (Ybt) siderophore system. To determine whether the Ent and Ybt systems are functionally redundant for iron uptake, we compared the growth of different isogenic siderophore biosynthetic mutants in the presence of transferrin, a human iron-binding protein. We observed that Ybt expression does not compensate for deficient Ent expression following low-density inoculation. Using transcriptional and product analysis, we found this non-redundancy to be attributable to a density-dependent transcriptional stimulation cycle in which Ybt functions as an autoinducer. These results distinguish the Ybt system as a combined quorum-sensing and siderophore system. These functions may reflect Ybt as a public good within bacterial communities or as an adaptation to confined, subcellular compartments in infected hosts. This combined functionality may contribute to the extraintestinal pathogenic potential of E. coli and related Enterobacterales.IMPORTANCEPatients with urinary tract infections are often infected with Escherichia coli strains carrying adaptations that increase their pathogenic potential. One of these adaptations is the accumulation of multiple siderophore systems, which scavenge iron for nutritional use. While iron uptake is important for bacterial growth, the increased metabolic costs of siderophore production could diminish bacterial fitness during infections. In a siderophore-dependent growth condition, we show that the virulence-associated yersiniabactin siderophore system in uropathogenic E. coli is not redundant with the ubiquitous E. coli enterobactin system. This arises not from differences in iron-scavenging activity but because yersiniabactin is preferentially expressed during bacterial crowding, leaving bacteria dependent upon enterobactin for growth at low cell density. Notably, this regulatory mode arises because yersiniabactin stimulates its own expression, acting as an autoinducer in a previously unappreciated quorum-sensing system. This unexpected result connects quorum-sensing with pathogenic potential in E. coli and related Enterobacterales.
Collapse
Affiliation(s)
- James R. Heffernan
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - John A. Wildenthal
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hung Tran
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - George L. Katumba
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - William H. McCoy
- Division of Dermatology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jeffrey P. Henderson
- Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| |
Collapse
|
2
|
Heffernan JR, Katumba GL, McCoy WH, Henderson JP. Yersiniabactin is a quorum sensing autoinducer and siderophore in uropathogenic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.09.527953. [PMID: 36798367 PMCID: PMC9934619 DOI: 10.1101/2023.02.09.527953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Siderophores are secreted ferric ion chelators used to obtain iron in nutrient-limited environmental niches, including human hosts. While all E. coli encode the enterobactin (Ent) siderophore system, isolates from patients with urinary tract infections additionally encode the genetically distinct yersiniabactin (Ybt) siderophore system. To determine whether the Ent and Ybt systems are functionally redundant for iron uptake, we compared growth of different isogenic siderophore biosynthesis mutants in the presence of transferrin, a human iron-binding protein. We observed that the Ybt system does not compensate for loss of the Ent system during siderophore-dependent, low density growth. Using transcriptional and product analysis, we found that this non-redundancy is attributable to a density-dependent transcriptional stimulation cycle in which Ybt assume an additional autoinducer function. These results distinguish the Ybt system as a combined quorum-sensing and siderophore system. These functions may reflect Ybt as a public good within bacterial communities or as an adaptation to confined, subcellular compartments in infected hosts. The efficiency of this arrangement may contribute to the extraintestinal pathogenic potential of E. coli and related Enterobacterales. IMPORTANCE Urinary tract infections (UTIs) are one of the most common human bacterial infections encountered by physicians. Adaptations that increase the pathogenic potential of commensal microbes such as E.coli are of great interest. One potential adaptation observed in clinical isolates is accumulation of multiple siderophore systems, which scavenge iron for nutritional use. While iron uptake is important for bacterial growth, the increased metabolic costs of siderophore production could diminish bacterial fitness during infections. In a siderophore-dependent growth conditions, we show that the virulence-associated yersiniabactin siderophore system in uropathogenic E. coli is not redundant with the ubiquitous E. coli enterobactin system. This arises not from differences in iron scavenging activity but because yersiniabactin is preferentially expressed during bacterial crowding, leaving bacteria dependent upon enterobactin for growth at low cell density. Notably, this regulatory mode arises because yersiniabactin stimulates its own expression, acting as an autoinducer in a previously unappreciated quorum-sensing system. This unexpected result connects quorum-sensing with pathogenic potential in E. coli and related Enterobacterales.
Collapse
|
3
|
Recipient Cell Factors Influence Interbacterial Competition Mediated by Two Distinct Burkholderia dolosa Contact-Dependent Growth Inhibition Systems. J Bacteriol 2022; 204:e0054121. [PMID: 36000834 PMCID: PMC9487645 DOI: 10.1128/jb.00541-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Contact-dependent growth inhibition (CDI) systems mediate interbacterial antagonism between Gram-negative bacteria by delivering the toxic portion of a large surface protein (termed BcpA in Burkholderia species) to the cytoplasm of neighboring bacteria. Translocation of the antibacterial polypeptide into recipient cells requires specific recipient outer and inner membrane proteins, but the identity of these factors outside several model organisms is unknown. To identify genes involved in CDI susceptibility in the Burkholderia cepacia complex member Burkholderia dolosa, a transposon mutagenesis selection approach was used to enrich for mutants resistant to BcpA-1 or BcpA-2. Subsequent analysis showed that candidate regulatory genes contributed modestly to recipient cell susceptibility to B. dolosa CDI. However, most candidate deletion mutants did not show the same phenotypes as the corresponding transposon mutants. Whole-genome resequencing revealed that these transposon mutants also contained unique mutations within a three gene locus (wabO, BDAG_01006, and BDAG_01005) encoding predicted lipopolysaccharide (LPS) biosynthesis enzymes. B. dolosa wabO, BDAG_01006, or BDAG_01005 mutants were resistant to CDI and produced LPS with altered core oligosaccharide and O-antigen. Although BcpA-1 and BcpA-2 are dissimilar and expected to utilize different outer membrane receptors, intoxication by both proteins was similarly impacted by LPS changes. Together, these findings suggest that alterations in cellular regulation may indirectly impact the efficiency of CDI-mediated competition and demonstrate that LPS is required for intoxication by two distinct B. dolosa BcpA proteins. IMPORTANCEContact-dependent growth inhibition (CDI) system proteins, produced by many Gram-negative bacteria, are narrow spectrum antimicrobials that inhibit the growth of closely related neighboring bacteria. Here, we use the opportunistic pathogen Burkholderia dolosa to identify genes required for intoxication by two distinct CDI system proteins. Our findings suggest that B. dolosa recipient cells targeted by CDI systems are only intoxicated if they produce full-length lipopolysaccharide. Understanding the mechanisms underlying antagonistic interbacterial interactions may contribute to future therapeutic development.
Collapse
|
4
|
On the origin of amphi-enterobactin fragments produced by Vibrio campbellii species. J Biol Inorg Chem 2022; 27:565-572. [PMID: 35834122 PMCID: PMC9470620 DOI: 10.1007/s00775-022-01949-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/07/2022] [Indexed: 11/15/2022]
Abstract
Amphi-enterobactin is an amphiphilic siderophore isolated from a variety of microbial Vibrio species. Like enterobactin, amphi-enterobactin is a triscatecholate siderophore; however, it is framed on an expanded tetralactone core comprised of four l-Ser residues, of which one l-Ser is appended by a fatty acid and the remaining l-Ser residues are appended by 2,3-dihydroxybenzoate (DHB). Fragments of amphi-enterobactin composed of 2-Ser-1-DHB-FA and 3-Ser-2-DHB-FA have been identified in the supernatant of Vibrio campbellii species. The origin of these fragments has not been determined, although two distinct isomers could exist for 2-Ser-1-DHB-FA and three distinct isomers could exist for 3-Ser-2-DHB-FA. The fragments of amphi-enterobactin could originate from hydrolysis of the amphi-enterobactin macrolactone, or from premature release due to an inefficient biosynthetic pathway. Unique masses in the tandem MS analysis establish that certain fragments isolated from the culture supernatant must originate from hydrolysis of the amphi-enterobactin macrolactone, while others cannot be distinguished from premature release during biosynthesis or hydrolysis of amphi-enterobactin.
Collapse
|
5
|
Grove A. Extracytoplasmic Function Sigma Factors Governing Production of the Primary Siderophores in Pathogenic Burkholderia Species. Front Microbiol 2022; 13:851011. [PMID: 35283809 PMCID: PMC8908255 DOI: 10.3389/fmicb.2022.851011] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria respond to changing environments by modulating their gene expression programs. One of the mechanisms by which this may be accomplished is by substituting the primary σ factor with an alternative σ factor belonging to the family of extracytoplasmic function (ECF) σ factors. ECF σ factors are activated only in presence of specific signals, and they direct the RNA polymerase (RNAP) to transcribe a defined subset of genes. One condition, which may trigger the activation of an ECF σ factor, is iron limitation. To overcome iron starvation, bacteria produce and secrete siderophores, which chelate iron and facilitate its cellular uptake. In the genus Burkholderia, which includes several serious human pathogens, uptake of iron is critical for virulence, and expression of biosynthetic gene clusters encoding proteins involved in synthesis and transport of the primary siderophores are under control of an ECF σ factor. This review summarizes mechanisms involved in regulation of these gene clusters, including the role of global transcriptional regulators. Since siderophore-mediated iron acquisition is important for virulence, interference with this process constitutes a viable approach to the treatment of bacterial infections.
Collapse
Affiliation(s)
- Anne Grove
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
| |
Collapse
|
6
|
Barrera-Galicia GC, Peniche-Pavía HA, Peña-Cabriales JJ, Covarrubias SA, Vera-Núñez JA, Délano-Frier JP. Metabolic Footprints of Burkholderia Sensu Lato Rhizosphere Bacteria Active against Maize Fusarium Pathogens. Microorganisms 2021; 9:microorganisms9102061. [PMID: 34683382 PMCID: PMC8538949 DOI: 10.3390/microorganisms9102061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022] Open
Abstract
Consistent with their reported abundance in soils, several Burkholderia sensu lato strains were isolated from the rhizosphere of maize plants cultivated at different sites in central México. Comparative analysis of their 16S rRNA gene sequences permitted their separation into three distinctive clades, which were further subdivided into six other clusters by their close resemblance to (1) Trinickia dinghuensis; (2) Paraburkholderia kirstenboschensis, P. graminis, P. dilworthii and P. rhynchosiae; (3) B. gladioli; (4) B. arboris; (5) B. contaminans, or (6) B. metallica representative species. Direct confrontation assays revealed that these strains inhibited the growth of pathogenic Fusarium oxysporum f. sp. radicis-lycopersici, and F. verticillioides within a roughly 3-55% inhibition range. The use of a DIESI-based non-targeted mass spectroscopy experimental strategy further indicated that this method is an option for rapid determination of the pathogen inhibitory capacity of Burkholderia sensu lato strains based solely on the analysis of their exometabolome. Furthermore, it showed that the highest anti-fungal activity observed in B. contaminans and B. arboris was associated with a distinctive abundance of certain m/z ions, some of which were identified as components of the ornbactin and pyochelin siderophores. These results highlight the chemical diversity of Burkholderia sensu lato bacteria and suggest that their capacity to inhibit the Fusarium-related infection of maize in suppressive soils is associated with siderophore synthesis.
Collapse
Affiliation(s)
- Guadalupe C. Barrera-Galicia
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Irapuato, Irapuato 36824, Guanajuato, Mexico; (G.C.B.-G.); (H.A.P.-P.); (J.J.P.-C.)
| | - Héctor A. Peniche-Pavía
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Irapuato, Irapuato 36824, Guanajuato, Mexico; (G.C.B.-G.); (H.A.P.-P.); (J.J.P.-C.)
| | - Juan José Peña-Cabriales
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Irapuato, Irapuato 36824, Guanajuato, Mexico; (G.C.B.-G.); (H.A.P.-P.); (J.J.P.-C.)
| | - Sergio A. Covarrubias
- Área de Ciencias de la Salud, Ciudad Universitaria Campus Siglo XXI, Universidad Autónoma de Zacatecas, Zacatecas 98160, Zacatecas, Mexico; (S.A.C.); (J.A.V.-N.)
| | - José A. Vera-Núñez
- Área de Ciencias de la Salud, Ciudad Universitaria Campus Siglo XXI, Universidad Autónoma de Zacatecas, Zacatecas 98160, Zacatecas, Mexico; (S.A.C.); (J.A.V.-N.)
| | - John P. Délano-Frier
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Irapuato, Irapuato 36824, Guanajuato, Mexico; (G.C.B.-G.); (H.A.P.-P.); (J.J.P.-C.)
- Correspondence: ; Tel.: +52-462-623-9600
| |
Collapse
|
7
|
Ortiz BJ, Jennings J, Gross WS, Santos TMA, Lin TY, Weibel DB, Lynn DM. Soft Materials that Intercept, Respond to, and Sequester Bacterial Siderophores. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2021; 33:5401-5412. [PMID: 35341019 PMCID: PMC8945880 DOI: 10.1021/acs.chemmater.1c01530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report the design and characterization of Fe-containing soft materials that respond to, interface with, and/or sequester Fe-chelating 'siderophores' that bacteria use to scavenge for iron and regulate iron homeostasis. We demonstrate that metal-organic network coatings fabricated by crosslinking tannic acid with iron(III) are stable in bacterial growth media, but erode upon exposure to biologically relevant concentrations of enterobactin and deferoxamine B, two siderophores produced by Gram-negative and Gram-positive bacteria, respectively. Our results are consistent with changes in network stability triggered by the extraction of iron(III) and reveal rates of siderophore-induced disassembly to depend upon both siderophore concentration and affinity for iron(III). These coatings also disassemble when incubated in the presence of cultures of wild-type Escherichia coli. Assays using genetically modified strains of E. coli reveal the erosion of these materials by live cultures to be promoted by secretion of enterobactin and not from other factors resulting from bacterial growth and metabolism. This stimuli-responsive behavior can also be exploited to design coatings that release the Fe-chelating antibiotic ciprofloxacin into bacterial cultures. Finally, we report the discovery of Fe-containing polymer hydrogels that avidly sequester and scavenge enterobactin from surrounding media. The materials reported here are (i) capable of interfacing or interfering with mechanisms that bacteria use to maintain iron homeostasis, either by yielding iron to or by sequestering iron-scavenging agents from bacteria, and can (ii) respond dynamically to or report on the presence of populations of iron-scavenging bacteria. Our results thus provide new tools that could prove useful for microbiological research and enable new stimuli-responsive strategies for interfacing with or controlling the behaviors of communities of iron-scavenging bacteria.
Collapse
Affiliation(s)
- Benjamin J. Ortiz
- Department of Chemical and Biological Engineering, 1415 Engineering Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
| | - James Jennings
- Department of Chemistry, 1101 University Ave., University of Wisconsin–Madison, Madison, WI 53706, USA
| | - William S. Gross
- Department of Biochemistry, 433 Babcock Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Thiago M. A. Santos
- Department of Biochemistry, 433 Babcock Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Ti-Yu Lin
- Department of Biochemistry, 433 Babcock Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
| | - Douglas B. Weibel
- Department of Chemistry, 1101 University Ave., University of Wisconsin–Madison, Madison, WI 53706, USA
- Department of Biochemistry, 433 Babcock Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
- Department of Biomedical Engineering, 1550 Engineering. Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
- Current Address: Institute of Molecular Biosciences, Humboldtstraße 50, University of Graz, Graz 8010, Austria; (D.B.W.); (D.M.L.)
| | - David M. Lynn
- Department of Chemical and Biological Engineering, 1415 Engineering Dr., University of Wisconsin–Madison, Madison, WI 53706, USA
- Department of Chemistry, 1101 University Ave., University of Wisconsin–Madison, Madison, WI 53706, USA
- Current Address: Institute of Molecular Biosciences, Humboldtstraße 50, University of Graz, Graz 8010, Austria; (D.B.W.); (D.M.L.)
| |
Collapse
|
8
|
Presence of the Hmq System and Production of 4-Hydroxy-3-Methyl-2-Alkylquinolines Are Heterogeneously Distributed between Burkholderia cepacia Complex Species and More Prevalent among Environmental than Clinical Isolates. Microbiol Spectr 2021; 9:e0012721. [PMID: 34132614 PMCID: PMC8552760 DOI: 10.1128/spectrum.00127-21] [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: 12/23/2022] Open
Abstract
The Burkholderia cepacia complex (Bcc) comprises several species of closely related, versatile bacteria. Some Bcc strains produce 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), analogous to the 4-hydroxy-2-alkylquinolines of Pseudomonas aeruginosa. Using in silico analyses, we previously estimated that the hmqABCDEFG operon, which encodes enzymes involved in the biosynthesis of HMAQs, is carried by about one-third of Bcc strains, with considerable inter- and intraspecies variability. In the present study, we investigated by PCR, using consensus primers, the distribution of hmqABCDEFG in a collection of 312 Bcc strains (222 of clinical and 90 of environmental origins) belonging to 18 Bcc species. We confirmed that this operon is not distributed evenly among Bcc species. Among the 30% of strains bearing the hmqABCDEFG operon, we found that 92% of environmental isolates and 82% of clinically isolated Bcc strains produce levels of HMAQs detectable by liquid chromatography-mass spectrometry in at least one of the tested culture conditions. Among the hmqABCDEFG-positive but HMAQ-negative strains, none expressed the hmqA gene under the specified culture conditions. Interestingly, the hmqABCDEFG operon is more prevalent among plant root environment species (e.g., Burkholderia ambifaria and Burkholderia cepacia) and absent in species commonly found in chronically colonized individuals with cystic fibrosis (e.g., Burkholderia cenocepacia and Burkholderia multivorans), suggesting a role for the Hmq system in niche adaptation. We investigated the impact of the Hmq system on plant growth promotion and found that Pisum sativum root development by B. ambifaria required a functional HMAQ system. IMPORTANCE Environmental bacteria belonging to the various closely related species forming the Burkholderia cepacia complex (Bcc) can infect plants and animals, including humans. Their pathogenicity is regulated by intercellular communication, or quorum sensing, allowing them to collaborate instead of acting individually. Bcc organisms generally exploit interacting quorum sensing systems based on N-acyl-homoserine lactones as signaling molecules. Several Bcc strains also carry an hmqABCDEFG operon responsible for the biosynthesis of 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), molecules analogous to the Pseudomonas quinolone signal (PQS) system of P. aeruginosa. Our finding that the prevalences of the Hmq system and HMAQ production are very different between various Bcc species suggests a key role in niche adaptation or pathogenicity. This is supported by a significant reduction in plant growth promotion in the absence of HMAQ production for a beneficial Bcc strain.
Collapse
|
9
|
Tsukidate H, Otake S, Kato Y, Yoshimura K, Kitatsuji M, Yoshimura E, Suzuki M. Iron Elution from Iron and Steel Slag Using Bacterial Complex Identified from the Seawater. MATERIALS 2021; 14:ma14061477. [PMID: 33803029 PMCID: PMC8002712 DOI: 10.3390/ma14061477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 11/25/2022]
Abstract
Iron and steel slag (ISS) is a byproduct of iron refining processes. The lack of iron in seawater can cause barren grounds where algae cannot grow. To improve the barren grounds of the sea, a supply of iron to the seawater is necessary. This study focused on bacteria interacting with ISS and promoting iron elution in seawater. Sulfitobacter sp. (TO1A) and Pseudomonas sp. (TO1B) were isolated from Tokyo Bay and Sagami Bay. The co-culture of both bacteria promoted more iron elution than individual cultures. After the incubation of both bacteria with ISS, quartz and vaterite appeared on the surface of the ISS. To maintain continuous iron elution from the ISS in the seawater, we also isolated Pseudoalteromonas sp. (TO7) that formed a yellow biofilm on the ISS. Iron was eluted by TO1A and TO1B, and biofilm was synthesized by TO7 continuously in the seawater. The present research is expected to contribute to the improvement of ISS usage as a material for the construction of seaweed forests.
Collapse
Affiliation(s)
- Hidenori Tsukidate
- Department of Applied Biological Chemistry, Graduate School of Agriculture, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan; (H.T.); (S.O.); (Y.K.); (E.Y.)
| | - Seika Otake
- Department of Applied Biological Chemistry, Graduate School of Agriculture, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan; (H.T.); (S.O.); (Y.K.); (E.Y.)
| | - Yugo Kato
- Department of Applied Biological Chemistry, Graduate School of Agriculture, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan; (H.T.); (S.O.); (Y.K.); (E.Y.)
| | - Ko Yoshimura
- Advanced Technology Research Laboratories, Nippon Steel, 20-1 Shintomi, Futtsu, Chiba 293-0011, Japan;
| | - Masafumi Kitatsuji
- School of Food Industrial Sciences, Miyagi University, 2-2-1 Hatatate, Tauhaku, Sendai, Miyagi 982-0215, Japan;
| | - Etsuro Yoshimura
- Department of Applied Biological Chemistry, Graduate School of Agriculture, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan; (H.T.); (S.O.); (Y.K.); (E.Y.)
- Department of Liberal Arts, The Open University of Japan, 2-11 Wakaba, Mishima-ku, Chiba 261-8586, Japan
| | - Michio Suzuki
- Department of Applied Biological Chemistry, Graduate School of Agriculture, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan; (H.T.); (S.O.); (Y.K.); (E.Y.)
- Correspondence:
| |
Collapse
|
10
|
McAvoy AC, Jaiyesimi O, Threatt PH, Seladi T, Goldberg JB, da Silva RR, Garg N. Differences in Cystic Fibrosis-Associated Burkholderia spp. Bacteria Metabolomes after Exposure to the Antibiotic Trimethoprim. ACS Infect Dis 2020; 6:1154-1168. [PMID: 32212725 DOI: 10.1021/acsinfecdis.9b00513] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The Burkholderia cepacia complex is a group of closely related bacterial species with large genomes that infect immunocompromised individuals and those living with cystic fibrosis. Some of these species are found more frequently and cause more severe disease than others, yet metabolomic differences between these have not been described. Furthermore, our understanding of how these species respond to antibiotics is limited. We investigated the metabolomics differences between three most prevalent Burkholderia spp. associated with cystic fibrosis: B. cenocepacia, B. multivorans, and B. dolosa in the presence and absence of the antibiotic trimethoprim. Using a combination of supervised and unsupervised metabolomics data visualization and analysis tools, we describe the overall differences between strains of the same species and between species. Specifically, we report, for the first time, the role of the pyomelanin pathway in the metabolism of trimethoprim. We also report differences in the detection of known secondary metabolites such as fragin, ornibactin, and N-acylhomoserine lactones and their analogs in closely related strains. Furthermore, we highlight the potential for the discovery of new secondary metabolites in clinical strains of Burkholderia spp. The metabolomics differences described in this study highlight the personalized nature of closely related Burkholderia strains.
Collapse
Affiliation(s)
- Andrew C. McAvoy
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Olakunle Jaiyesimi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Paxton H. Threatt
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Tyler Seladi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
| | - Joanna B. Goldberg
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Emory University School of Medicine, 1510 Clifton Road NE, Suite 3009, Atlanta, Georgia 30322, United States
- Emory-Children’s Cystic Fibrosis Center, Atlanta, Georgia 30322, United States
| | - Ricardo R. da Silva
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Av. do Café - Vila Monte Alegre, Ribeirão Preto, São Paulo 14040-903, Brazil
| | - Neha Garg
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, Georgia 30332-2000, United States
- Department of Pediatrics, Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Emory University School of Medicine, 1510 Clifton Road NE, Suite 3009, Atlanta, Georgia 30322, United States
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, 311 Ferst Drive, ES&T, Atlanta, Georgia 30332, United States
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 311 Ferst Drive, ES&T, Atlanta, Georgia 30322, United States
| |
Collapse
|
11
|
Phenylacetyl Coenzyme A, Not Phenylacetic Acid, Attenuates CepIR-Regulated Virulence in Burkholderia cenocepacia. Appl Environ Microbiol 2019; 85:AEM.01594-19. [PMID: 31585996 DOI: 10.1128/aem.01594-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/30/2019] [Indexed: 11/20/2022] Open
Abstract
During phenylalanine catabolism, phenylacetic acid (PAA) is converted to phenylacetyl coenzyme A (PAA-CoA) by a ligase, PaaK, and then PAA-CoA is epoxidized by a multicomponent monooxygenase, PaaABCDE, before further degradation through the tricarboxylic acid (TCA) cycle. In the opportunistic pathogen Burkholderia cenocepacia, loss of paaABCDE attenuates virulence factor expression, which is under the control of the LuxIR-like quorum sensing (QS) system, CepIR. To further investigate the link between CepIR-regulated virulence and PAA catabolism, we created knockout mutants of the first step of the pathway (PAA-CoA synthesis by PaaK) and characterized them in comparison to a paaABCDE mutant using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and virulence assays. We found that while loss of PaaABCDE decreased virulence, deletion of the paaK genes resulted in a more virulent phenotype than that of the wild-type strain. Deletion of either paaK or paaABCDE led to higher levels of released PAA but no differences in levels of internal accumulation compared to the wild-type level. While we found no evidence of direct cepIR downregulation by PAA-CoA or PAA, a low-virulence cepR mutant reverted to a virulent phenotype upon removal of the paaK genes. On the other hand, removal of paaABCDE in the cepR mutant did not impact its attenuated phenotype. Together, our results suggest an indirect role for PAA-CoA in suppressing B. cenocepacia CepIR-activated virulence.IMPORTANCE The opportunistic pathogen Burkholderia cenocepacia uses a chemical signal process called quorum sensing (QS) to produce virulence factors. In B. cenocepacia, QS relies on the presence of the transcriptional regulator CepR which, upon binding QS signal molecules, activates virulence. In this work, we found that even in the absence of CepR, B. cenocepacia can elicit a pathogenic response if phenylacetyl-CoA, an intermediate of the phenylacetic acid degradation pathway, is not produced. Instead, accumulation of phenylacetyl-CoA appears to attenuate pathogenicity. Therefore, we have discovered that it is possible to trigger virulence in the absence of CepR, challenging the classical view of activation of virulence by this QS mechanism. Our work provides new insight into the relationship between metabolism and virulence in opportunistic bacteria. We propose that in the event that QS signaling molecules cannot accumulate to trigger a pathogenic response, a metabolic signal can still activate virulence in B. cenocepacia.
Collapse
|
12
|
Oppy CC, Jebeli L, Kuba M, Oates CV, Strugnell R, Edgington-Mitchell LE, Valvano MA, Hartland EL, Newton HJ, Scott NE. Loss of O-Linked Protein Glycosylation in Burkholderia cenocepacia Impairs Biofilm Formation and Siderophore Activity and Alters Transcriptional Regulators. mSphere 2019; 4:e00660-19. [PMID: 31722994 PMCID: PMC6854043 DOI: 10.1128/msphere.00660-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023] Open
Abstract
O-linked protein glycosylation is a conserved feature of the Burkholderia genus. The addition of the trisaccharide β-Gal-(1,3)-α-GalNAc-(1,3)-β-GalNAc to membrane exported proteins in Burkholderia cenocepacia is required for bacterial fitness and resistance to environmental stress. However, the underlying causes of the defects observed in the absence of glycosylation are unclear. Using proteomics, luciferase reporter assays, and DNA cross-linking, we demonstrate the loss of glycosylation leads to changes in transcriptional regulation of multiple proteins, including the repression of the master quorum CepR/I. These proteomic and transcriptional alterations lead to the abolition of biofilm formation and defects in siderophore activity. Surprisingly, the abundance of most of the known glycosylated proteins did not significantly change in the glycosylation-defective mutants, except for BCAL1086 and BCAL2974, which were found in reduced amounts, suggesting they could be degraded. However, the loss of these two proteins was not responsible for driving the proteomic alterations, biofilm formation, or siderophore activity. Together, our results show that loss of glycosylation in B. cenocepacia results in a global cell reprogramming via alteration of the transcriptional regulatory systems, which cannot be explained by the abundance changes in known B. cenocepacia glycoproteins.IMPORTANCE Protein glycosylation is increasingly recognized as a common posttranslational protein modification in bacterial species. Despite this commonality, our understanding of the role of most glycosylation systems in bacterial physiology and pathogenesis is incomplete. In this work, we investigated the effect of the disruption of O-linked glycosylation in the opportunistic pathogen Burkholderia cenocepacia using a combination of proteomic, molecular, and phenotypic assays. We find that in contrast to recent findings on the N-linked glycosylation systems of Campylobacter jejuni, O-linked glycosylation does not appear to play a role in proteome stabilization of most glycoproteins. Our results reveal that loss of glycosylation in B. cenocepacia strains leads to global proteome and transcriptional changes, including the repression of the quorum-sensing regulator cepR (BCAM1868) gene. These alterations lead to dramatic phenotypic changes in glycosylation-null strains, which are paralleled by both global proteomic and transcriptional alterations, which do not appear to directly result from the loss of glycosylation per se. This research unravels the pleiotropic effects of O-linked glycosylation in B. cenocepacia, demonstrating that its loss does not simply affect the stability of the glycoproteome, but also interferes with transcription and the broader proteome.
Collapse
Affiliation(s)
- Cameron C Oppy
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Miku Kuba
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Clare V Oates
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Richard Strugnell
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Laura E Edgington-Mitchell
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, Bluestone Center for Clinical Research, New York, New York, USA
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Elizabeth L Hartland
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| |
Collapse
|
13
|
Chua KO, See-Too WS, Ee R, Lim YL, Yin WF, Chan KG. In silico Analysis Reveals Distribution of Quorum Sensing Genes and Consistent Presence of LuxR Solos in the Pandoraea Species. Front Microbiol 2019; 10:1758. [PMID: 31447806 PMCID: PMC6691176 DOI: 10.3389/fmicb.2019.01758] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/16/2019] [Indexed: 01/11/2023] Open
Abstract
The most common quorum sensing (QS) system in Gram-negative bacteria consists of signaling molecules called N-acyl-homoserine lactones (AHLs), which are synthesized by an enzyme AHL synthase (LuxI) and detected by a transcriptional regulator (LuxR) that are usually located in close proximity. However, many recent studies have also evidenced the presence of LuxR solos that are LuxR-related proteins in Proteobacteria that are devoid of a cognate LuxI AHL synthase. Pandoraea species are opportunistic pathogens frequently isolated from sputum specimens of cystic fibrosis (CF) patients. We have previously shown that P. pnomenusa strains possess QS activity. In this study, we examined the presence of QS activity in all type strains of Pandoraea species and acquired their complete genome sequences for holistic bioinformatics analyses of QS-related genes. Only four out of nine type strains (P. pnomenusa, P. sputorum, P. oxalativorans, and P. vervacti) showed QS activity, and C8-HSL was the only AHL detected. A total of 10 canonical luxIs with adjacent luxRs were predicted by bioinformatics from the complete genomes of aforementioned species and publicly available Pandoraea genomes. No orphan luxI was identified in any of the genomes. However, genes for two LuxR solos (LuxR2 and LuxR3 solos) were identified in all Pandoraea genomes (except two draft genomes with one LuxR solo gene), and P. thiooxydans was the only species that harbored no QS-related activity and genes. Except the canonical LuxR genes, LuxIs and LuxR solos of Pandoraea species were distantly related to the other well-characterized QS genes based on phylogenetic clustering. LuxR2 and LuxR3 solos might represent two novel evolutionary branches of LuxR system as they were found exclusively only in the genus. As a few luxR solos were located in close proximity with prophage sequence regions in the genomes, we thus postulated that these luxR solos could be transmitted into genus Pandoraea by transduction process mediated by bacteriophage. The bioinformatics approach developed in this study forms the basis for further characterization of closely related species. Overall, our findings improve the current understanding of QS in Pandoraea species, which is a potential pharmacological target in battling Pandoraea infections in CF patients.
Collapse
Affiliation(s)
- Kah-Ooi Chua
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Wah-Seng See-Too
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Robson Ee
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Yan-Lue Lim
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.,International Genome Centre, Jiangsu University, Zhenjiang, China
| |
Collapse
|
14
|
Jenner M, Jian X, Dashti Y, Masschelein J, Hobson C, Roberts DM, Jones C, Harris S, Parkhill J, Raja HA, Oberlies NH, Pearce CJ, Mahenthiralingam E, Challis GL. An unusual Burkholderia gladioli double chain-initiating nonribosomal peptide synthetase assembles 'fungal' icosalide antibiotics. Chem Sci 2019; 10:5489-5494. [PMID: 31293732 PMCID: PMC6553374 DOI: 10.1039/c8sc04897e] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/22/2019] [Indexed: 11/21/2022] Open
Abstract
Fungus-associated Burkholderia gladioli bacteria use a unique ‘dual-priming’ nonribosomal peptide synthetase to assemble icosalide A1.
Burkholderia is a multi-talented genus of Gram-negative bacteria, which in recent years has become increasingly recognised as a promising source of bioactive natural products. Metabolite profiling of Burkholderia gladioli BCC0238 showed that it produces the asymmetric lipopeptidiolide antibiotic icosalide A1, originally isolated from a fungus. Comparative bioinformatics analysis of several genome-sequenced B. gladioli isolates identified a gene encoding a nonribosomal peptide synthase (NRPS) with an unusual architecture that was predicted to be responsible for icosalide biosynthesis. Inactivation of this gene in B. gladioli BCC0238 abolished icosalide production. PCR analysis and sequencing of total DNA from the original fungal icosalide A1 producer revealed it has a B. gladioli strain associated with it that harbours an NRPS with an identical architecture to that responsible for icosalide A1 assembly in B. gladioli BCC0238. Sequence analysis of the icosalide NRPS indicated that it contains two chain-initiating condensation (CI) domains. One of these is appended to the N-terminus of module 1 – a common architecture for NRPSs involved in lipopeptide assembly. The other is embedded in module 3, immediately downstream of a putative chain-elongating condensation domain. Analysis of the reactions catalysed by a tridomain construct from module 3 of the NRPS using intact protein mass spectrometry showed that the embedded CI domain initiates assembly of a second lipopeptide chain, providing key insights into the mechanism for asymmetric diolide assembly.
Collapse
Affiliation(s)
- Matthew Jenner
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK . .,Warwick Integrative Synthetic Biology Centre , University of Warwick , Coventry CV4 7AL , UK
| | - Xinyun Jian
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK .
| | - Yousef Dashti
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK .
| | - Joleen Masschelein
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK .
| | - Christian Hobson
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK .
| | - Douglas M Roberts
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK .
| | - Cerith Jones
- Organisms and Environment Division , Cardiff School of Biosciences , Cardiff University , Main Building, Park Place , Cardiff CF10 3AT , UK
| | - Simon Harris
- Wellcome Trust Sanger Institute , Wellcome Trust Genome Campus , Hinxton , Cambridge CB10 1SA , UK
| | - Julian Parkhill
- Wellcome Trust Sanger Institute , Wellcome Trust Genome Campus , Hinxton , Cambridge CB10 1SA , UK
| | - Huzefa A Raja
- Department of Chemistry and Biochemistry , University , of North Carolina at Greensboro , Greensboro , NC 27402 , USA
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry , University , of North Carolina at Greensboro , Greensboro , NC 27402 , USA
| | - Cedric J Pearce
- Mycosynthetix , 4905 Pine Cone Drive , Durham , North Carolina 27707 , USA
| | - Eshwar Mahenthiralingam
- Organisms and Environment Division , Cardiff School of Biosciences , Cardiff University , Main Building, Park Place , Cardiff CF10 3AT , UK
| | - Gregory L Challis
- Department of Chemistry , University of Warwick , Coventry CV4 7AL , UK . .,Warwick Integrative Synthetic Biology Centre , University of Warwick , Coventry CV4 7AL , UK.,Biomedicine Discovery Institute , Department of Biochemistry and Molecular Biology , Monash University , Victoria 3800 , Australia
| |
Collapse
|
15
|
Coulon PML, Groleau MC, Déziel E. Potential of the Burkholderia cepacia Complex to Produce 4-Hydroxy-3-Methyl-2-Alkyquinolines. Front Cell Infect Microbiol 2019; 9:33. [PMID: 30873388 PMCID: PMC6403149 DOI: 10.3389/fcimb.2019.00033] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 02/01/2019] [Indexed: 12/22/2022] Open
Abstract
A few Burkholderia species, especially Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia ambifaria, and Burkholderia cepacia, are known to produce and release various 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs), a family of molecules analogous to the 4-hydroxy-2-alkylquinolines [aka 2-n-alkyl-4(1H)-quinolones] of Pseudomonas aeruginosa, which include the Pseudomonas quinolone signal (PQS). However, while these exoproducts play several roles in P. aeruginosa virulence and survival, the available literature is very limited on their distribution and function in Burkholderia. In this perspective article, we studied the distribution of the hmqABCDEFG operon, which encodes the enzymes involved in the biosynthesis of HMAQs, in the Burkholderia cepacia complex (Bcc) group. Based on the available sequence data, about one third of Bcc species carry a homolog of the hmqABCDEFG, and not all sequenced strains in a given species possess this operon. Looking at the synteny of genes surrounding the hmqABCDEFG operon, we found that for some species, the operon seems to have been deleted or replaced by other genes. Finally, we review the literature on the possible function of HMAQs. Understanding the Hmq system may provide clues concerning their functions in Bcc.
Collapse
Affiliation(s)
- Pauline M L Coulon
- Institut Armand Frappier, Institut National de la Recherche Scientifique, Laval, QC, Canada
| | | | - Eric Déziel
- Institut Armand Frappier, Institut National de la Recherche Scientifique, Laval, QC, Canada
| |
Collapse
|
16
|
Quorum sensing and iron regulate a two-for-one siderophore gene cluster in Vibrio harveyi. Proc Natl Acad Sci U S A 2018; 115:7581-7586. [PMID: 29954861 DOI: 10.1073/pnas.1805791115] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The secretion of small Fe-binding molecules called siderophores is an important microbial strategy for survival in Fe-limited environments. Siderophore production is often regulated by quorum sensing (QS), a microbial counting technique that allows organisms to alter gene expression based on cell density. However, the identity and quantities of siderophores produced under QS regulation are rarely studied in the context of their roles in Fe uptake. We investigated the link between QS, siderophores, and Fe uptake in the model marine organism Vibrio harveyi where QS is thought to repress siderophore production. We find that V. harveyi uses a single QS- and Fe-repressed gene cluster to produce both cell-associated siderophores (amphiphilic enterobactins) as well as several related soluble siderophores, which we identify and quantify using liquid chromatography-coupled (LC)-MS as well as tandem high-resolution MS (LC-HR-MS/MS). Measurements of siderophore production show that soluble siderophores are present at ∼100× higher concentrations than amphi-enterobactin and that over the course of growth V. harveyi decreases amphi-enterobactin concentrations but accumulates soluble siderophores. 55Fe radio-tracer uptake experiments demonstrate that these soluble siderophores play a significant role in Fe uptake and that the QS-dictated concentrations of soluble siderophores in stationary phase are near the limit of cellular uptake capacities. We propose that cell-associated and soluble siderophores are beneficial to V. harveyi in different environmental and growth contexts and that QS allows V. harveyi to exploit "knowledge" of its population size to avoid unnecessary siderophore production.
Collapse
|
17
|
Involvement of Burkholderiaceae and sulfurous volatiles in disease-suppressive soils. ISME JOURNAL 2018; 12:2307-2321. [PMID: 29899517 DOI: 10.1038/s41396-018-0186-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/12/2018] [Accepted: 03/20/2018] [Indexed: 01/08/2023]
Abstract
Disease-suppressive soils are ecosystems in which plants suffer less from root infections due to the activities of specific microbial consortia. The characteristics of soils suppressive to specific fungal root pathogens are comparable to those of adaptive immunity in animals, as reported by Raaijmakers and Mazzola (Science 352:1392-3, 2016), but the mechanisms and microbial species involved in the soil suppressiveness are largely unknown. Previous taxonomic and metatranscriptome analyses of a soil suppressive to the fungal root pathogen Rhizoctonia solani revealed that members of the Burkholderiaceae family were more abundant and more active in suppressive than in non-suppressive soils. Here, isolation, phylogeny, and soil bioassays revealed a significant disease-suppressive activity for representative isolates of Burkholderia pyrrocinia, Paraburkholderia caledonica, P. graminis, P. hospita, and P. terricola. In vitro antifungal activity was only observed for P. graminis. Comparative genomics and metabolite profiling further showed that the antifungal activity of P. graminis PHS1 was associated with the production of sulfurous volatile compounds encoded by genes not found in the other four genera. Site-directed mutagenesis of two of these genes, encoding a dimethyl sulfoxide reductase and a cysteine desulfurase, resulted in a loss of antifungal activity both in vitro and in situ. These results indicate that specific members of the Burkholderiaceae family contribute to soil suppressiveness via the production of sulfurous volatile compounds.
Collapse
|
18
|
Roux D, Schaefers M, Clark BS, Weatherholt M, Renaud D, Scott D, LiPuma JJ, Priebe G, Gerard C, Yoder-Himes DR. A putative lateral flagella of the cystic fibrosis pathogen Burkholderia dolosa regulates swimming motility and host cytokine production. PLoS One 2018; 13:e0189810. [PMID: 29346379 PMCID: PMC5773237 DOI: 10.1371/journal.pone.0189810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 12/01/2017] [Indexed: 01/25/2023] Open
Abstract
Burkholderia dolosa caused an outbreak in the cystic fibrosis clinic at Boston Children's Hospital and was associated with high mortality in these patients. This species is part of a larger complex of opportunistic pathogens known as the Burkholderia cepacia complex (Bcc). Compared to other species in the Bcc, B. dolosa is highly transmissible; thus understanding its virulence mechanisms is important for preventing future outbreaks. The genome of one of the outbreak strains, AU0158, revealed a homolog of the lafA gene encoding a putative lateral flagellin, which, in other non-Bcc species, is used for movement on solid surfaces, attachment to host cells, or movement inside host cells. Here, we analyzed the conservation of the lafA gene and protein sequences, which are distinct from those of the polar flagella, and found lafA homologs to be present in numerous β-proteobacteria but notably absent from most other Bcc species. A lafA deletion mutant in B. dolosa showed a greater swimming motility than wild-type due to an increase in the number of polar flagella, but did not appear to contribute to biofilm formation, host cell invasion, or murine lung colonization or persistence over time. However, the lafA gene was important for cytokine production in human peripheral blood mononuclear cells, suggesting it may have a role in recognition by the human immune response.
Collapse
Affiliation(s)
- Damien Roux
- INSERM, IAME, UMR 1137, Paris, France
- Univ Paris Diderot, Sorbonne Paris Cité, Paris, France
- AP-HP, Louis Mourier Hospital, Intensive Care Unit, Colombes, France
| | - Matthew Schaefers
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Anesthesia, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bradley S. Clark
- Department of Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Molly Weatherholt
- Department of Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Diane Renaud
- Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, Kentucky, United States of America
| | - David Scott
- Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, Kentucky, United States of America
| | - John J. LiPuma
- Division of Pediatrics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Gregory Priebe
- Division of Critical Care Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Anesthesia, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Craig Gerard
- Division of Respiratory Diseases, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Deborah R. Yoder-Himes
- Department of Biology, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
| |
Collapse
|
19
|
The Complex Quorum Sensing Circuitry of Burkholderia thailandensis Is Both Hierarchically and Homeostatically Organized. mBio 2017; 8:mBio.01861-17. [PMID: 29208745 PMCID: PMC5717390 DOI: 10.1128/mbio.01861-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The genome of the bacterium Burkholderia thailandensis encodes three complete LuxI/LuxR-type quorum sensing (QS) systems: BtaI1/BtaR1 (QS-1), BtaI2/BtaR2 (QS-2), and BtaI3/BtaR3 (QS-3). The LuxR-type transcriptional regulators BtaR1, BtaR2, and BtaR3 modulate the expression of target genes in association with various N-acyl-l-homoserine lactones (AHLs) as signaling molecules produced by the LuxI-type synthases BtaI1, BtaI2, and BtaI3. We have systematically dissected the complex QS circuitry of B. thailandensis strain E264. Direct quantification of N-octanoyl-homoserine lactone (C8-HSL), N-3-hydroxy-decanoyl-homoserine lactone (3OHC10-HSL), and N-3-hydroxy-octanoyl-homoserine lactone (3OHC8-HSL), the primary AHLs produced by this bacterium, was performed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the wild-type strain and in QS deletion mutants. This was compared to the transcription of btaI1, btaI2, and btaI3 using chromosomal mini-CTX-lux transcriptional reporters. Furthermore, the levels of expression of btaR1, btaR2, and btaR3 were monitored by quantitative reverse transcription-PCR (qRT-PCR). We observed that C8-HSL, 3OHC10-HSL, and 3OHC8-HSL are differentially produced over time during bacterial growth and correlate with the btaI1, btaI2, and btaI3 gene expression profiles, revealing a successive activation of the corresponding QS systems. Moreover, the transcription of the btaR1, btaR2, and btaR3 genes is modulated by cognate and noncognate AHLs, showing that their regulation depends on themselves and on other QS systems. We conclude that the three QS systems in B. thailandensis are interdependent, suggesting that they cooperate dynamically and function in a concerted manner in modulating the expression of QS target genes through a successive regulatory network. Quorum sensing (QS) is a widespread bacterial communication system coordinating the expression of specific genes in a cell density-dependent manner and allowing bacteria to synchronize their activities and to function as multicellular communities. QS plays a crucial role in bacterial pathogenicity by regulating the expression of a wide spectrum of virulence/survival factors and is essential to environmental adaptation. The results presented here demonstrate that the multiple QS systems coexisting in the bacterium Burkholderia thailandensis, which is considered the avirulent version of the human pathogen Burkholderia pseudomallei and thus commonly used as an alternative study model, are hierarchically and homeostatically organized. We found these QS systems to be finely integrated into a complex regulatory network, including transcriptional and posttranscriptional interactions, and further incorporating growth stages and temporal expression. These results provide a unique, comprehensive illustration of a sophisticated QS network and will contribute to a better comprehension of the regulatory mechanisms that can be involved in the expression of QS-controlled genes, in particular those associated with the establishment of host-pathogen interactions and acclimatization to the environment.
Collapse
|
20
|
Immune Recognition of the Epidemic Cystic Fibrosis Pathogen Burkholderia dolosa. Infect Immun 2017; 85:IAI.00765-16. [PMID: 28348057 DOI: 10.1128/iai.00765-16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 03/20/2017] [Indexed: 12/31/2022] Open
Abstract
Burkholderia dolosa caused an outbreak in the cystic fibrosis (CF) clinic at Boston Children's Hospital from 1998 to 2005 and led to the infection of over 40 patients, many of whom died due to complications from infection by this organism. To assess whether B. dolosa significantly contributes to disease or is recognized by the host immune response, mice were infected with a sequenced outbreak B. dolosa strain, AU0158, and responses were compared to those to the well-studied CF pathogen Pseudomonas aeruginosa In parallel, mice were also infected with a polar flagellin mutant of B. dolosa to examine the role of flagella in B. dolosa lung colonization. The results showed a higher persistence in the host by B. dolosa strains, and yet, neutrophil recruitment and cytokine production were lower than those with P. aeruginosa The ability of host immune cells to recognize B. dolosa was then assessed, B. dolosa induced a robust cytokine response in cultured cells, and this effect was dependent on the flagella only when bacteria were dead. Together, these results suggest that B. dolosa can be recognized by host cells in vitro but may avoid or suppress the host immune response in vivo through unknown mechanisms. B. dolosa was then compared to other Burkholderia species and found to induce similar levels of cytokine production despite being internalized by macrophages more than Burkholderia cenocepacia strains. These data suggest that B. dolosa AU0158 may act differently with host cells and is recognized differently by immune systems than are other Burkholderia strains or species.
Collapse
|
21
|
Discovery of new diketopiperazines inhibiting Burkholderia cenocepacia quorum sensing in vitro and in vivo. Sci Rep 2016; 6:32487. [PMID: 27580679 PMCID: PMC5007513 DOI: 10.1038/srep32487] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/08/2016] [Indexed: 02/08/2023] Open
Abstract
Burkholderia cenocepacia, an opportunistic respiratory pathogen particularly relevant for cystic fibrosis patients, is difficult to eradicate due to its high level of resistance to most clinically relevant antimicrobials. Consequently, the discovery of new antimicrobials as well as molecules capable of inhibiting its virulence is mandatory. In this regard quorum sensing (QS) represents a good target for anti-virulence therapies, as it has been linked to biofilm formation and is important for the production of several virulence factors, including proteases and siderophores. Here, we report the discovery of new diketopiperazine inhibitors of the B. cenocepacia acyl homoserine lactone synthase CepI, and report their anti-virulence properties. Out of ten different compounds assayed against recombinant CepI, four were effective inhibitors, with IC50 values in the micromolar range. The best compounds interfered with protease and siderophore production, as well as with biofilm formation, and showed good in vivo activity in a Caenorhabditis elegans infection model. These molecules were also tested in human cells and showed very low toxicity. Therefore, they could be considered for in vivo combined treatments with established or novel antimicrobials, to improve the current therapeutic strategies against B. cenocepacia.
Collapse
|
22
|
Huang J, Shi Y, Zeng G, Gu Y, Chen G, Shi L, Hu Y, Tang B, Zhou J. Acyl-homoserine lactone-based quorum sensing and quorum quenching hold promise to determine the performance of biological wastewater treatments: An overview. CHEMOSPHERE 2016; 157:137-151. [PMID: 27213243 DOI: 10.1016/j.chemosphere.2016.05.032] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/21/2016] [Accepted: 05/11/2016] [Indexed: 06/05/2023]
Abstract
Quorum sensing (QS) is a communication process between cells, in which bacteria secrete and sense the specific chemicals, and regulate gene expression in response to population density. Quorum quenching (QQ) blocks QS system, and inhibits gene expression mediating bacterial behaviors. Given the extensive research of acyl-homoserine lactone (AHL) signals, existences and effects of AHL-based QS and QQ in biological wastewater treatments are being subject to high concern. This review summarizes AHL structure, synthesis mode, degradation mechanisms, analytical methods, environmental factors, AHL-based QS and QQ mechanisms. The existences and roles of AHL-based QS and QQ in biomembrane processes, activated sludge processes and membrane bioreactors are summarized and discussed, and corresponding exogenous regulation strategy by selective enhancement of AHL-based QS or QQ coexisting in biological wastewater treatments is suggested. Such strategies including the addition of AHL signals, AHL-producing bacteria as well as quorum quenching enzyme or bacteria can effectively improve wastewater treatment performance without killing or limiting bacterial survival and growth. This review will present the theoretical and practical cognition for bacterial AHL-based QS and QQ, suggest the feasibility of exogenous regulation strategies in biological wastewater treatments, and provide useful information to scientists and engineers who work in this field.
Collapse
Affiliation(s)
- Jinhui Huang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China.
| | - Yahui Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Yanling Gu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Guiqiu Chen
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Lixiu Shi
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Yi Hu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Bi Tang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| | - Jianxin Zhou
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, Hunan, 410082, China
| |
Collapse
|
23
|
How KY, Hong KW, Chan KG. Whole genome sequencing enables the characterization of BurI, a LuxI homologue of Burkholderia cepacia strain GG4. PeerJ 2015; 3:e1117. [PMID: 26290785 PMCID: PMC4540015 DOI: 10.7717/peerj.1117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 06/30/2015] [Indexed: 01/24/2023] Open
Abstract
Quorum sensing is a mechanism for regulating proteobacterial gene expression in response to changes in cell population. In proteobacteria, N-acyl homoserine lactone (AHL) appears to be the most widely used signalling molecules in mediating, among others, the production of extracellular virulence factors for survival. In this work, the genome of B. cepacia strain GG4, a plasmid-free strain capable of AHL synthesis was explored. In silico analysis of the 6.6 Mb complete genome revealed the presence of a LuxI homologue which correspond to Type I quorum sensing. Here, we report the molecular cloning and characterization of this LuxI homologue, designated as BurI. This 609 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was approximately 25 kDa and is highly similar to several autoinducer proteins of the LuxI family among Burkholderia species. To verify the AHL synthesis activity of this protein, high resolution liquid chromatography-mass spectrometry analysis revealed the production of 3-oxo-hexanoylhomoserine lactone, N-octanoylhomoserine lactone and 3-hydroxy-octanoylhomoserine lactone from induced E. coli BL21 harboring the recombinant BurI. Our data show, for the first time, the cloning and characterization of the LuxI homologue from B. cepacia strain GG4 and confirmation of its AHL synthesis activity.
Collapse
Affiliation(s)
- Kah Yan How
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| | - Kar Wai Hong
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia
| |
Collapse
|
24
|
Stopnisek N, Zühlke D, Carlier A, Barberán A, Fierer N, Becher D, Riedel K, Eberl L, Weisskopf L. Molecular mechanisms underlying the close association between soil Burkholderia and fungi. ISME JOURNAL 2015; 10:253-64. [PMID: 25989372 DOI: 10.1038/ismej.2015.73] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 01/27/2023]
Abstract
Bacterial species belonging to the genus Burkholderia have been repeatedly reported to be associated with fungi but the extent and specificity of these associations in soils remain undetermined. To assess whether associations between Burkholderia and fungi are widespread in soils, we performed a co-occurrence analysis in an intercontinental soil sample collection. This revealed that Burkholderia significantly co-occurred with a wide range of fungi. To analyse the molecular basis of the interaction, we selected two model fungi frequently co-occurring with Burkholderia, Alternaria alternata and Fusarium solani, and analysed the proteome changes caused by cultivation with either fungus in the widespread soil inhabitant B. glathei, whose genome we sequenced. Co-cultivation with both fungi led to very similar changes in the B. glathei proteome. Our results indicate that B. glathei significantly benefits from the interaction, which is exemplified by a lower abundance of several starvation factors that were highly expressed in pure culture. However, co-cultivation also gave rise to stress factors, as indicated by the increased expression of multidrug efflux pumps and proteins involved in oxidative stress response. Our data suggest that the ability of Burkholderia to establish a close association with fungi mainly lies in the capacities to utilize fungal-secreted metabolites and to overcome fungal defense mechanisms. This work indicates that beneficial interactions with fungi might contribute to the survival strategy of Burkholderia species in environments with sub-optimal conditions, including acidic soils.
Collapse
Affiliation(s)
- Nejc Stopnisek
- Institute of Plant Biology, University of Zurich, Zürich, Switzerland.,Institute for Sustainability Sciences, Agroscope, Zürich, Switzerland
| | - Daniela Zühlke
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Aurélien Carlier
- Institute of Plant Biology, University of Zurich, Zürich, Switzerland
| | - Albert Barberán
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Noah Fierer
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Dörte Becher
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Katharina Riedel
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Leo Eberl
- Institute of Plant Biology, University of Zurich, Zürich, Switzerland
| | - Laure Weisskopf
- Institute of Plant Biology, University of Zurich, Zürich, Switzerland.,Institute for Sustainability Sciences, Agroscope, Zürich, Switzerland
| |
Collapse
|
25
|
Pribytkova T, Lightly TJ, Kumar B, Bernier SP, Sorensen JL, Surette MG, Cardona ST. The attenuated virulence of aBurkholderia cenocepacia paaABCDEmutant is due to inhibition of quorum sensing by release of phenylacetic acid. Mol Microbiol 2014; 94:522-36. [DOI: 10.1111/mmi.12771] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Tanya Pribytkova
- Department of Microbiology; University of Manitoba; Winnipeg Manitoba Canada
| | - Tasia Joy Lightly
- Department of Microbiology; University of Manitoba; Winnipeg Manitoba Canada
| | - Brijesh Kumar
- Department of Microbiology; University of Manitoba; Winnipeg Manitoba Canada
| | - Steve P. Bernier
- Department of Medicine; Farncombe Family Digestive Health Research Institute; McMaster University; Hamilton Ontario Canada
| | - John L. Sorensen
- Department of Chemistry; University of Manitoba; Winnipeg Manitoba Canada
| | - Michael G. Surette
- Department of Medicine; Farncombe Family Digestive Health Research Institute; McMaster University; Hamilton Ontario Canada
- Department of Biochemistry and Biological Sciences; McMaster University; Hamilton Ontario Canada
| | - Silvia T. Cardona
- Department of Microbiology; University of Manitoba; Winnipeg Manitoba Canada
- Department of Medical Microbiology & Infectious Disease; University of Manitoba; Winnipeg Manitoba Canada
| |
Collapse
|
26
|
Goh SY, Tan WS, Khan SA, Chew HP, Abu Kasim NH, Yin WF, Chan KG. Unusual multiple production of N-acylhomoserine lactones a by Burkholderia sp. strain C10B isolated from dentine caries. SENSORS 2014; 14:8940-9. [PMID: 24854358 PMCID: PMC4063041 DOI: 10.3390/s140508940] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 05/04/2014] [Accepted: 05/13/2014] [Indexed: 01/12/2023]
Abstract
Bacteria realize the ability to communicate by production of quorum sensing (QS) molecules called autoinducers, which regulate the physiological activities in their ecological niches. The oral cavity could be a potential area for the presence of QS bacteria. In this study, we report the isolation of a QS bacterial isolate C10B from dentine caries. Preliminary screening using Chromobacterium violaceum CV026 biosensor showed that isolate C10B was able to produce N-acylhomoserine lactones (AHLs). This bacterium was further identified as a member of Burkholderia, an opportunistic pathogen. The isolated Burkholderia sp. was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL), N-octanoyl-L-homoserine lactone (C8-HSL), N-decanoyl-L-homoserine lactone (C10-HSL) and N-dodecanoyl-L-homoserine lactone (C12-HSL).
Collapse
Affiliation(s)
- Share Yuan Goh
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Wen-Si Tan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Saad Ahmed Khan
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Hooi Pin Chew
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Noor Hayaty Abu Kasim
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| |
Collapse
|
27
|
Role for ferredoxin:NAD(P)H oxidoreductase (FprA) in sulfate assimilation and siderophore biosynthesis in Pseudomonads. J Bacteriol 2013; 195:3876-87. [PMID: 23794620 DOI: 10.1128/jb.00528-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyridine-2,6-bis(thiocarboxylate) (PDTC), produced by certain pseudomonads, is a sulfur-containing siderophore that binds iron, as well as a wide range of transition metals, and it affects the net hydrolysis of the environmental contaminant carbon tetrachloride. The pathway of PDTC biosynthesis has not been defined. Here, we performed a transposon screen of Pseudomonas putida DSM 3601 to identify genes necessary for PDTC production (Pdt phenotype). Transposon insertions within genes for sulfate assimilation (cysD, cysNC, and cysG [cobA2]) dominated the collection of Pdt mutations. In addition, two insertions were within the gene for the LysR-type transcriptional activator FinR (PP1637). Phenotypic characterization indicated that finR mutants were cysteine bradytrophs. The Pdt phenotype of finR mutants could be complemented by the known target of FinR regulation, fprA (encoding ferredoxin:NADP(+) oxidoreductase), or by Escherichia coli cysJI (encoding sulfite reductase). These data indicate that fprA is necessary for effective sulfate assimilation by P. putida and that the effect of finR mutation on PDTC production was due to deficient expression of fprA and sulfite reduction. fprA expression in both P. putida and P. aeruginosa was found to be regulated by FinR, but in a manner dependent upon reduced sulfur sources, implicating FinR in sulfur regulatory physiology. The genes and phenotypes identified in this study indicated a strong dependence upon intracellular reduced sulfur/cysteine for PDTC biosynthesis and that pseudomonads utilize sulfite reduction enzymology distinct from that of E. coli and possibly similar to that of chloroplasts and other proteobacteria.
Collapse
|
28
|
Subramoni S, Sokol PA. Quorum sensing systems influence Burkholderia cenocepacia virulence. Future Microbiol 2013; 7:1373-87. [PMID: 23231487 DOI: 10.2217/fmb.12.118] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Burkholderia cepacia complex strains communicate using N-acyl homoserine lactones and BDSF-dependent quorum sensing (QS) systems. Burkholderia cenocepacia QS systems include CepIR, CciIR, CepR2 and BDSF. Analysis of CepR, CciIR, CepR2 and RpfF (BDSF synthase) QS regulons revealed that these QS systems both independently regulate and coregulate many target genes, often in an opposing manner. The role of QS and several QS-regulated genes in virulence has been determined using vertebrate, invertebrate and plant infection models. Virulence phenotypes are strain and model dependent, suggesting that different QS-regulated genes are important depending on the strain and type of infection. QS inhibitors in combination with antibiotics can reduce biofilm formation and virulence in infection models.
Collapse
Affiliation(s)
- Sujatha Subramoni
- Department of Microbiology, Immunology & Infectious Diseases, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
| | | |
Collapse
|
29
|
Ryan GT, Wei Y, Winans SC. A LuxR-type repressor of Burkholderia cenocepacia inhibits transcription via antiactivation and is inactivated by its cognate acylhomoserine lactone. Mol Microbiol 2012; 87:94-111. [PMID: 23136852 DOI: 10.1111/mmi.12085] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2012] [Indexed: 11/30/2022]
Abstract
Burkholderia cenocepacia is an opportunistic human pathogen that encodes two LuxI-type acylhomoserine lactone (AHL) synthases and three LuxR-type AHL receptors. Of these, cepI and cepR form a cognate synthase/receptor pair, as do cciI and cciR, while cepR2 lacks a genetically linked AHL synthase gene. Another group showed that a cepR2 mutant overexpressed a cluster of linked genes that appear to direct the production of a secondary metabolite. We found that these same genes were upregulated by octanoylhomoserine lactone (OHL), which is synthesized by CepI. These data suggest that several cepR2-linked promoters are repressed by CepR2 and that CepR2 is antagonized by OHL. Fusions of two divergent promoters to lacZ were used to confirm these hypotheses, and promoter resections and DNase I footprinting assays revealed a single CepR2 binding site between the two promoters. This binding site lies well upstream of both promoters, suggesting an unusual mode of repression. Adjacent to the cepR2 gene is a gene that we designate cepS, which encodes an AraC-type transcription factor. CepS is essential for expression of both promoters, regardless of the CepR2 status or OHL concentration. CepS therefore acts downstream of CepR2, and CepR2 appears to function as a CepS antiactivator.
Collapse
Affiliation(s)
- Gina T Ryan
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | | | | |
Collapse
|
30
|
Aubert DF, O'Grady EP, Hamad MA, Sokol PA, Valvano MA. The Burkholderia cenocepacia sensor kinase hybrid AtsR is a global regulator modulating quorum-sensing signalling. Environ Microbiol 2012; 15:372-85. [PMID: 22830644 DOI: 10.1111/j.1462-2920.2012.02828.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Burkholderia cenocepacia is commonly found in the environment and also as an important opportunistic pathogen infecting patients with cystic fibrosis. Successful infection by this bacterium requires coordinated expression of virulence factors, which is achieved through different quorum sensing (QS) regulatory systems. Biofilm formation and Type 6 secretion system (T6SS) expression in B. cenocepacia K56-2 are positively regulated by QS and negatively regulated by the sensor kinase hybrid AtsR. This study reveals that in addition to affecting biofilm and T6SS activity, the deletion of atsR in B. cenocepacia leads to overproduction of other QS-regulated virulence determinants including proteases and swarming motility. Expression of the QS genes, cepIR and cciIR, was upregulated in the ΔatsR mutant and resulted in early and increased N-acylhomoserine lactone (AHL) production, suggesting that AtsR plays a role in controlling the timing and fine-tuning of virulence gene expression by modulating QS signalling. Furthermore, a ΔatsRΔcepIΔcciI mutant could partially upregulate the same virulence determinants indicating that AtsR also modulates the expression of virulence genes by a second mechanism, independently of any AHL production. Together, our results strongly suggest that AtsR is a global virulence regulator in B. cenocepacia.
Collapse
Affiliation(s)
- Daniel F Aubert
- Centre for Human Immunology, Department of Microbiology, University of Western Ontario, London, Ontario, Canada
| | | | | | | | | |
Collapse
|
31
|
O'Grady EP, Viteri DF, Sokol PA. A unique regulator contributes to quorum sensing and virulence in Burkholderia cenocepacia. PLoS One 2012; 7:e37611. [PMID: 22624054 PMCID: PMC3356288 DOI: 10.1371/journal.pone.0037611] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 04/23/2012] [Indexed: 01/08/2023] Open
Abstract
Burkholderia cenocepacia causes chronic and life-threatening respiratory infections in immunocompromized people. The B. cenocepacia N-acyl-homoserine lactone (AHL)-dependent quorum sensing system relies on the production of AHLs by the synthases CepI and CciI while CepR, CciR and CepR2 control expression of many genes important for pathogenesis. Downstream from, and co-transcribed with cepI, lies BCAM1871 encoding a hypothetical protein that was uncharacterized prior to this study. Orthologs of B. cenocepacia BCAM1871 are uniquely found in Burkholderia spp and are conserved in their genomic locations in pathogenic Burkholderia. We observed significant effects on AHL activity upon mutation or overexpression of BCAM1871, although these effects were more subtle than those observed for CepI indicating BCAM1871 acts as an enhancer of AHL activity. Transcription of cepI, cepR and cciIR was significantly reduced in the BCAM1871 mutant. Swimming and swarming motilities as well as transcription of fliC, encoding flagellin, were significantly reduced in the BCAM1871 mutant. Protease activity and transcription of zmpA and zmpB, encoding extracellular zinc metalloproteases, were undetectable in the BCAM1871 mutant indicating a more significant effect of mutating BCAM1871 than cepI. Exogenous addition of OHL restored cepI, cepR and fliC transcription but had no effect on motility, protease activity or zmpA or zmpB transcription suggesting AHL-independent effects. The BCAM1871 mutant exhibited significantly reduced virulence in rat chronic respiratory and nematode infection models. Gene expression and phenotypic assays as well as vertebrate and invertebrate infection models showed that BCAM1871 significantly contributes to pathogenesis in B. cenocepacia.
Collapse
Affiliation(s)
| | | | - Pamela A. Sokol
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
| |
Collapse
|
32
|
Veselova MA, Lipasova VA, Zaitseva YV, Koksharova OA, Chernukha MY, Romanova YM, Khmel’ IA. Mutants of Burkholderia cenocepacia with a change in synthesis of N-acyl-homoserine lactones—Signal molecules of quorum sensing regulation. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412050213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
33
|
Abstract
Many bacteria use 'quorum sensing' (QS) as a mechanism to regulate gene induction in a population-dependent manner. In its simplest sense this involves the accumulation of a signaling metabolite during growth; the binding of this metabolite to a regulator or multiple regulators activates induction or repression of gene expression. However QS regulation is seldom this simple, because other inputs are usually involved. In this review we have focussed on how those other inputs influence QS regulation and as implied by the title, this often occurs by environmental or physiological effects regulating the expression or activity of the QS regulators. The rationale of this review is to briefly introduce the main QS signals used in Gram-negative bacteria and then introduce one of the earliest understood mechanisms of regulation of the regulator, namely the plant-mediated control of expression of the TraR QS regulator in Agrobacterium tumefaciens. We then describe how in several species, multiple QS regulatory systems can act as integrated hierarchical regulatory networks and usually this involves the regulation of QS regulators. Such networks can be influenced by many different physiological and environmental inputs and we describe diverse examples of these. In the final section, we describe different examples of how eukaryotes can influence QS regulation in Gram-negative bacteria.
Collapse
Affiliation(s)
- Marijke Frederix
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | |
Collapse
|
34
|
Eberl L, Riedel K. Mining quorum sensing regulated proteins - Role of bacterial cell-to-cell communication in global gene regulation as assessed by proteomics. Proteomics 2011; 11:3070-85. [PMID: 21548094 DOI: 10.1002/pmic.201000814] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 01/20/2011] [Accepted: 02/17/2011] [Indexed: 12/31/2022]
Affiliation(s)
- Leo Eberl
- Department of Microbiology, Institute of Plant Biology, University of Zürich, Zurich, Switzerland
| | | |
Collapse
|
35
|
Wei Y, Ryan GT, Flores-Mireles AL, Costa ED, Schneider DJ, Winans SC. Saturation mutagenesis of a CepR binding site as a means to identify new quorum-regulated promoters in Burkholderia cenocepacia. Mol Microbiol 2011; 79:616-32. [PMID: 21255107 DOI: 10.1111/j.1365-2958.2010.07469.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Burkholderia cenocepacia is an opportunistic pathogen of humans that encodes two genes that resemble the acylhomoserine lactone synthase gene luxI of Vibrio fischeri and three genes that resemble the acylhomoserine lactone receptor gene luxR. Of these, CepI synthesizes octanoylhomoserine lactone (OHL), while CepR is an OHL-dependent transcription factor. In the current study we developed a strategy to identify genes that are directly regulated by CepR. We systematically altered a CepR binding site (cep box) upstream of a target promoter to identify nucleotides that are essential for CepR activity in vivo and for CepR binding in vitro. We constructed 34 self-complementary oligonucleotides containing altered cep boxes, and measured binding affinity for each. These experiments allowed us to identify a consensus CepR binding site. Several hundred similar sequences were identified, some of which were adjacent to probable promoters. Several such promoters were fused to a reporter gene with and without intact cep boxes. This allowed us to identify four new regulated promoters that were induced by OHL, and that required a cep box for induction. CepR-dependent, OHL-dependent expression of all four promoters was reconstituted in Escherichia coli. Purified CepR bound to each of these sites in electrophoretic mobility shift assays.
Collapse
Affiliation(s)
- Yuping Wei
- Departments of Microbiology Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | | | | | | | | | | |
Collapse
|
36
|
Di Cagno R, De Angelis M, Calasso M, Gobbetti M. Proteomics of the bacterial cross-talk by quorum sensing. J Proteomics 2011; 74:19-34. [DOI: 10.1016/j.jprot.2010.09.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/14/2010] [Accepted: 09/29/2010] [Indexed: 01/03/2023]
|
37
|
McKeon SA, Nguyen DT, Viteri DF, Zlosnik JEA, Sokol PA. Functional quorum sensing systems are maintained during chronic Burkholderia cepacia complex infections in patients with cystic fibrosis. J Infect Dis 2010; 203:383-92. [PMID: 21208930 DOI: 10.1093/infdis/jiq054] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Quorum sensing (QS) contributes to the virulence of Pseudomonas aeruginosa and Burkholderia cepacia complex lung infections. P. aeruginosa QS mutants are frequently isolated from patients with cystic fibrosis. The objective of this study was to determine whether similar adaptations occur over time in B. cepacia complex isolates. Forty-five Burkholderia multivorans and Burkholderia cenocepacia sequential isolates from patients with cystic fibrosis were analyzed for N-acyl-homoserine lactone activity. All but one isolate produced N-acyl-homoserine lactones. The B. cenocepacia N-acyl-homoserine lactone-negative isolate contained mutations in cepR and cciR. Growth competition assays were performed that compared B. cenocepacia clinical and laboratory defined wild-type and QS mutants. Survival of the laboratory wild-type and QS mutants varied, dependent on the mutation. The clinical wild-type isolate demonstrated a growth advantage over its QS mutant. These data suggest that there is a selective advantage for strains with QS systems and that QS mutations do not occur at a high frequency in B. cepacia complex isolates.
Collapse
Affiliation(s)
- Suzanne A McKeon
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | | | | | | | | |
Collapse
|
38
|
The Burkholderia cenocepacia LysR-type transcriptional regulator ShvR influences expression of quorum-sensing, protease, type II secretion, and afc genes. J Bacteriol 2010; 193:163-76. [PMID: 20971902 DOI: 10.1128/jb.00852-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cenocepacia is a significant opportunistic pathogen in individuals with cystic fibrosis. ShvR, a LysR-type transcriptional regulator, has previously been shown to influence colony morphology, biofilm formation, virulence in plant and animal infection models, and some quorum-sensing-dependent phenotypes. In the present study, it was shown that ShvR negatively regulates its own expression, as is typical for LysR-type regulators. The production of quorum-sensing signal molecules was detected earlier in growth in the shvR mutant than in the wild type, and ShvR repressed expression of the quorum-sensing regulatory genes cepIR and cciIR. Microarray analysis and transcriptional fusions revealed that ShvR regulated over 1,000 genes, including the zinc metalloproteases zmpA and zmpB. The shvR mutant displayed increased gene expression of the type II secretion system and significantly increased protease and lipase activities. Both ShvR and CepR influence expression of a 24-kb genomic region adjacent to shvR that includes the afcA and afcC operons, required for the production of an antifungal agent; however, the reduction in expression was substantially greater in the shvR mutant than in the cepR mutant. Only the shvR mutation resulted in reduced antifungal activity against Rhizoctonia solani. ShvR, but not CepR, was shown to directly regulate expression of the afcA and afcC promoters. In summary, ShvR was determined to have a significant influence on the expression of quorum-sensing, protease, lipase, type II secretion, and afc genes.
Collapse
|
39
|
Pathogenicity, virulence factors, and strategies to fight against Burkholderia cepacia complex pathogens and related species. Appl Microbiol Biotechnol 2010; 87:31-40. [PMID: 20390415 DOI: 10.1007/s00253-010-2528-0] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/25/2010] [Accepted: 02/25/2010] [Indexed: 12/31/2022]
Abstract
The Burkholderia cepacia complex (Bcc) is a group of 17 closely related species of the beta-proteobacteria subdivision that emerged in the 1980s as important human pathogens, especially to patients suffering from cystic fibrosis. Since then, a remarkable progress has been achieved on the taxonomy and molecular identification of these bacteria. Although some progress have been achieved on the knowledge of the pathogenesis traits and virulence factors used by these bacteria, further work envisaging the identification of potential targets for the scientifically based design of new therapeutic strategies is urgently needed, due to the very difficult eradication of these bacteria with available therapies. An overview of these aspects of Bcc pathogenesis and opportunities for the design of future therapies is presented and discussed in this work.
Collapse
|
40
|
Wang J, Quan C, Wang X, Zhao P, Fan S. Extraction, purification and identification of bacterial signal molecules based on N-acyl homoserine lactones. Microb Biotechnol 2010; 4:479-90. [PMID: 21375695 PMCID: PMC3815260 DOI: 10.1111/j.1751-7915.2010.00197.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Bacteria possess an extraordinary repertoire for intercellular communication and social behaviour. This repertoire for bacterial communication, termed as quorum sensing (QS), depends on specific diffusible signal molecules. There are many different kinds of signal molecules in the bacterial community. Among those signal molecules, N‐acyl homoserine lactones (HSLs, in other publications also referred to as AHLs, acy‐HSLs etc.) are often employed as QS signal molecules for many Gram‐negative bacteria. Due to the specific structure and tiny amount of those HSL signal molecules, the characterization of HSLs has been the subject of extensive investigations in the last decades and has become a paradigm for bacteria intercellular signalling. In this article, different methods, including extraction, purification and characterization of HSLs, are reviewed. The review provides an insight into identification and characterization of new HSLs and other signal molecules for bacterial intercellular communication.
Collapse
Affiliation(s)
- Jianhua Wang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, China
| | | | | | | | | |
Collapse
|
41
|
Abstract
This review describes the chemistry of the bacterial biofilms including the chemistry of their constituents and signalling compounds that mediate or inhibit the formation of biofilms. Systems are described with special emphasis, in which quorum sensing molecules (autoinducers) trigger the formation of biofilms. In the first instance, N-acyl-L-homoserine lactones (AHLs) are the focus of this review, whereas the inter-species signal known as furanosyl borate diester and peptide autoinducers used by Gram-positive bacteria are not discussed in detail. Since the first discovery of an AHL autoinducer from Vibrio fischeri a large and further increasing number of different AHL structures from Gram-negative bacteria have been identified. This review gives a summary of all known AHL autoinducers and producing bacterial species. A few systems are discussed, where biofilm formation is suppressed by enzymatic degradation of AHL molecules or interference of secondary metabolites from other species with the quorum sensing systems of communicating bacteria. Finally, the multi-channel quorum sensing system, the intracellular downstream processing of the signal, and the resulting response of whole populations including biofilm formation are discussed for the Vibrio genus that has been extensively investigated.
Collapse
Affiliation(s)
- Jeroen S Dickschat
- Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, Braunschweig, Germany.
| |
Collapse
|
42
|
Cooper VS, Carlson WA, LiPuma JJ. Susceptibility of Caenorhabditis elegans to Burkholderia infection depends on prior diet and secreted bacterial attractants. PLoS One 2009; 4:e7961. [PMID: 19956737 PMCID: PMC2776534 DOI: 10.1371/journal.pone.0007961] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Accepted: 10/17/2009] [Indexed: 12/05/2022] Open
Abstract
The nematode Caenorhabditis elegans may be killed by certain pathogenic bacteria and thus is a model organism for studying interactions between bacteria and animal hosts. However, growing nematodes on prey bacteria may influence their susceptibility to potential pathogens. A method of axenic nematode culture was developed to isolate and quantify interactions between C. elegans and potentially pathogenic strains of the Burkholderia cepacia complex. Studying these dynamics in liquid solution rather than on agar surfaces minimized nematode avoidance behavior and resolved more differences among isolates. Most isolates of B. cenocepacia, B. ambifaria and B. cepacia caused 60–80% mortality of nematodes after 7 days, whereas isolates of B. multivorans caused less mortality (<25%) and supported nematode reproduction. However, some B. cenocepacia isolates recovered from chronic infections were much less virulent (5–28% mortality). As predicted, prior diet altered the outcome of interactions between nematodes and bacteria. When given the choice between Burkholderia and E. coli as prey on agar, axenically raised nematodes initially preferred most lethal Burkholderia isolates to E. coli as a food source, but this was not the case for nematodes fed E. coli, which avoided toxic Burkholderia. This food preference was associated with the cell-free supernatant and thus secreted compounds likely mediated bacterial-nematode interactions. This model, which isolates interactions between bacteria and nematodes from the effects of prior feeding, demonstrates that bacteria can influence nematode behavior and their susceptibility to pathogens.
Collapse
Affiliation(s)
- Vaughn S. Cooper
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, United States of America
- * E-mail:
| | - Wendy A. Carlson
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, United States of America
| | - John J. LiPuma
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| |
Collapse
|
43
|
Affiliation(s)
- Moriah Sandy
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
| | | |
Collapse
|
44
|
O'Grady EP, Viteri DF, Malott RJ, Sokol PA. Reciprocal regulation by the CepIR and CciIR quorum sensing systems in Burkholderia cenocepacia. BMC Genomics 2009; 10:441. [PMID: 19761612 PMCID: PMC2753556 DOI: 10.1186/1471-2164-10-441] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 09/17/2009] [Indexed: 01/10/2023] Open
Abstract
Background Burkholderia cenocepacia belongs to a group of closely related organisms called the B. cepacia complex (Bcc) which are important opportunistic human pathogens. B. cenocepacia utilizes a mechanism of cell-cell communication called quorum sensing to control gene expression including genes involved in virulence. The B. cenocepacia quorum sensing network includes the CepIR and CciIR regulatory systems. Results Global gene expression profiles during growth in stationary phase were generated using microarrays of B. cenocepacia cepR, cciR and cepRcciIR mutants. This is the first time CciR was shown to be a global regulator of quorum sensing gene expression. CepR was primarily responsible for positive regulation of gene expression while CciR generally exerted negative gene regulation. Many of the genes that were regulated by both quorum sensing systems were reciprocally regulated by CepR and CciR. Microarray analysis of the cepRcciIR mutant suggested that CepR is positioned upstream of CciR in the quorum sensing hierarchy in B. cenocepacia. A comparison of CepIR-regulated genes identified in previous studies and in the current study showed a substantial amount of overlap validating the microarray approach. Several novel quorum sensing-controlled genes were confirmed using qRT-PCR or promoter::lux fusions. CepR and CciR inversely regulated flagellar-associated genes, the nematocidal protein AidA and a large gene cluster on Chromosome 3. CepR and CciR also regulated genes required for iron transport, synthesis of extracellular enzymes and surface appendages, resistance to oxidative stress, and phage-related genes. Conclusion For the first time, the influence of CciIR on global gene regulation in B. cenocepacia has been elucidated. Novel genes under the control of the CepIR and CciIR quorum sensing systems in B. cenocepacia have been identified. The two quorum sensing systems exert reciprocal regulation of many genes likely enabling fine-tuned control of quorum sensing gene expression in B. cenocepacia strains carrying the cenocepacia island.
Collapse
Affiliation(s)
- Eoin P O'Grady
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
| | | | | | | |
Collapse
|
45
|
Boyer M, Wisniewski-Dyé F. Cell-cell signalling in bacteria: not simply a matter of quorum. FEMS Microbiol Ecol 2009; 70:1-19. [PMID: 19689448 DOI: 10.1111/j.1574-6941.2009.00745.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bacterial signalling known as quorum sensing (QS) relies on the synthesis of autoinducing signals throughout growth; when a threshold concentration is reached, these signals interact with a transcriptional regulator, allowing the expression of specific genes at a high cell density. One of the most studied intraspecies signalling is based on the use of N-acyl-homoserine lactones (AHL). Many factors other than cell density were shown to affect AHL accumulation and interfere with the QS signalling process. At the cellular level, the genetic determinants of QS are integrated in a complex regulatory network, including QS cascades and various transcriptional and post-transcriptional regulators that affect the synthesis of the AHL signal. In complex environments where bacteria exist, AHL do not accumulate at a constant rate; the diffusion and perception of the AHL signal outside bacterial cells can be compromised by abiotic environmental factors, by members of the bacterial community such as AHL-degrading bacteria and also by compounds produced by eukaryotes acting as an AHL mimic or inhibitor. This review aims to present all factors interfering with the AHL-mediated signalling process, at the levels of signal production, diffusion and perception.
Collapse
|
46
|
Duerkop BA, Varga J, Chandler JR, Peterson SB, Herman JP, Churchill MEA, Parsek MR, Nierman WC, Greenberg EP. Quorum-sensing control of antibiotic synthesis in Burkholderia thailandensis. J Bacteriol 2009; 191:3909-18. [PMID: 19376863 PMCID: PMC2698390 DOI: 10.1128/jb.00200-09] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Accepted: 04/06/2009] [Indexed: 11/20/2022] Open
Abstract
The genome of Burkholderia thailandensis codes for several LuxR-LuxI quorum-sensing systems. We used B. thailandensis quorum-sensing deletion mutants and recombinant Escherichia coli to determine the nature of the signals produced by one of the systems, BtaR2-BtaI2, and to show that this system controls genes required for the synthesis of an antibiotic. BtaI2 is an acyl-homoserine lactone (acyl-HSL) synthase that produces two hydroxylated acyl-HSLs, N-3-hydroxy-decanoyl-HSL (3OHC(10)-HSL) and N-3-hydroxy-octanoyl-HSL (3OHC(8)-HSL). The btaI2 gene is positively regulated by BtaR2 in response to either 3OHC(10)-HSL or 3OHC(8)-HSL. The btaR2-btaI2 genes are located within clusters of genes with annotations that suggest they are involved in the synthesis of polyketide or peptide antibiotics. Stationary-phase cultures of wild-type B. thailandensis, but not a btaR2 mutant or a strain deficient in acyl-HSL synthesis, produced an antibiotic effective against gram-positive bacteria. Two of the putative antibiotic synthesis gene clusters require BtaR2 and either 3OHC(10)-HSL or 3OHC(8)-HSL for activation. This represents another example where antibiotic synthesis is controlled by quorum sensing, and it has implications for the evolutionary divergence of B. thailandensis and its close relatives Burkholderia pseudomallei and Burkholderia mallei.
Collapse
Affiliation(s)
- Breck A Duerkop
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195-7242, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
A Burkholderia cenocepacia orphan LuxR homolog is involved in quorum-sensing regulation. J Bacteriol 2009; 191:2447-60. [PMID: 19201791 DOI: 10.1128/jb.01746-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Burkholderia cenocepacia utilizes quorum sensing to control gene expression, including the expression of genes involved in virulence. In addition to CepR and CciR, a third LuxR homolog, CepR2, was found to regulate gene expression and virulence factor production. All B. cenocepacia strains examined contained this orphan LuxR homolog, which was not associated with an adjacent N-acyl-homoserine lactone synthase gene. Expression of cepR2 was negatively autoregulated and was negatively regulated by CciR in strain K56-2. Microarray analysis and quantitative reverse transcription-PCR determined that CepR2 did not influence expression of cepIR or cciIR. However, in strain K56-2, CepR2 negatively regulated expression of several known quorum-sensing-controlled genes, including genes encoding zinc metalloproteases. CepR2 exerted positive and negative regulation on genes on three chromosomes, including strong negative regulation of a gene cluster located adjacent to cepR2. In strain H111, which lacks the CciIR quorum-sensing system, CepR2 positively regulated pyochelin production by controlling transcription of one of the operons required for the biosynthesis of the siderophore in an N-acyl-homoserine lactone-independent manner. CepR2 activation of a luxI promoter was demonstrated in a heterologous Escherichia coli host, providing further evidence that CepR2 can function in the absence of signaling molecules. This study demonstrates that the orphan LuxR homolog CepR2 contributes to the quorum-sensing regulatory network in two distinct strains of B. cenocepacia.
Collapse
|
48
|
De Soyza A, Silipo A, Lanzetta R, Govan JR, Molinaro A. Chemical and biological features of Burkholderia cepacia complex lipopolysaccharides. Innate Immun 2008; 14:127-44. [PMID: 18562572 DOI: 10.1177/1753425908093984] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Burkholderia cepacia complex comprises 10 closely related Gram-negative organisms all of which appear capable of causing disease in humans. These organisms appear of particular relevance to patients with cystic fibrosis. Lipopolysaccharide (LPS) is an important virulence determinant in Gram-negative pathogens. In this review, we highlight important data within the field commenting on LPS/lipid A structure-to-function relationships and cytokine induction capacity of Burkholderia strains studied so far.
Collapse
Affiliation(s)
- Anthony De Soyza
- Transplantation and Immunobiology Group, Institute of Cellular Medicine, Newcastle University and The Freeman Hospital, Newcastle-upon-Tyne, UK.
| | | | | | | | | |
Collapse
|
49
|
Pontes MH, Babst M, Lochhead R, Oakeson K, Smith K, Dale C. Quorum sensing primes the oxidative stress response in the insect endosymbiont, Sodalis glossinidius. PLoS One 2008; 3:e3541. [PMID: 18958153 PMCID: PMC2568817 DOI: 10.1371/journal.pone.0003541] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 10/06/2008] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Sodalis glossinidius, a maternally transmitted bacterial endosymbiont of tsetse flies (Glossina spp.), uses an acylated homoserine lactone (AHL)-based quorum sensing system to modulate gene expression in accordance with bacterial cell density. The S. glossinidius quorum sensing system relies on the function of two regulatory proteins; SogI (a LuxI homolog) synthesizes a signaling molecule, characterized as N-(3-oxohexanoyl) homoserine lactone (OHHL), and SogR1 (a LuxR homolog) interacts with OHHL to modulate transcription of specific target genes. METHODOLOGY/PRINCIPAL FINDINGS We used a tiling microarray to analyze the S. glossinidius transcriptome in the presence and absence of exogenous OHHL. The major finding is that OHHL increases transcription of a large number of genes that are known to be involved in the oxidative stress response. We also show that the obligate symbiont of the rice weevil, Sitophilus oryzae (SOPE), maintains copies of the quorum sensing regulatory genes that are found in S. glossinidius. Molecular evolutionary analyses indicate that these sequences are evolving under stabilizing selection, consistent with the maintenance of their functions in the SOPE symbiosis. Finally, the expression studies in S. glossinidius also reveal that quorum sensing regulates the expression of a cryptic, degenerate gene (carA) that arose from an ancient deletion in the last common ancestor of S. glossinidius and SOPE. CONCLUSIONS/SIGNIFICANCE This oxidative stress response is likely mandated under conditions of dense intracellular symbiont infection, when intense metabolic activity is expected to generate a heavy oxidative burden. Such conditions are known to arise in the bacteriocytes of grain weevils, which harbor dense intracellular infections of symbiotic bacteria that are closely related to S. glossinidius. The presence of a degenerate carA sequence in S. glossinidius and SOPE indicates the potential for neofunctionalization to occur during the process of genome degeneration.
Collapse
Affiliation(s)
- Mauricio H Pontes
- Department of Biology, University of Utah, Salt Lake City, Utah, USA.
| | | | | | | | | | | |
Collapse
|
50
|
Bernier SP, Beeston AL, Sokol PA. Detection of N-acyl homoserine lactones using a traI-luxCDABE-based biosensor as a high-throughput screening tool. BMC Biotechnol 2008; 8:59. [PMID: 18667064 PMCID: PMC2518144 DOI: 10.1186/1472-6750-8-59] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Accepted: 07/30/2008] [Indexed: 11/10/2022] Open
Abstract
Background Bacteria use N-acyl homoserine lactone (AHL) molecules to regulate the expression of genes in a density-dependent manner. Several biosensors have been developed and engineered to detect the presence of all types of AHLs. Results In this study, we describe the usefulness of a traI-luxCDABE-based biosensor to quickly detect AHLs from previously characterized mutants of Burkholderia cenocepacia and Pseudomonas aeruginosa in both liquid and soft-agar co-culture assays in a high-throughput manner. The technique uses a co-culture system where the strain producing the AHLs is grown simultaneously with the reporter strain. Use of this assay in liquid co-culture allows the measurement of AHL activity in real time over growth. We tested this assay with Burkholderia cenocepacia and Pseudomonas aeruginosa but it should be applicable to a broad range of gram negative species that produce AHLs. Conclusion The co-culture assays described enable the detection of AHL production in both P. aeruginosa and B. cenocepacia and should be applicable to AHL analysis in other bacterial species. The high-throughput adaptation of the liquid co-culture assay could facilitate the screening of large libraries for the identification of mutants or compounds that block the synthesis or activity of AHLs.
Collapse
Affiliation(s)
- Steve P Bernier
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Canada.
| | | | | |
Collapse
|