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Han ZY, Chen QW, Zheng DW, Chen KW, Huang QX, Zhuang ZN, Zhang XZ. Inhalable Capsular Polysaccharide-Camouflaged Gallium-Polyphenol Nanoparticles Enhance Lung Cancer Chemotherapy by Depleting Local Lung Microbiota. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302551. [PMID: 37310059 DOI: 10.1002/adma.202302551] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/29/2023] [Indexed: 06/14/2023]
Abstract
Local lung microbiota is closely associated with lung tumorigenesis and therapeutic response. It is found that lung commensal microbes induce chemoresistance in lung cancer by directly inactivating therapeutic drugs via biotransformation. Accordingly, an inhalable microbial capsular polysaccharide (CP)-camouflaged gallium-polyphenol metal-organic network (MON) is designed to eliminate lung microbiota and thereby abrogate microbe-induced chemoresistance. As a substitute for iron uptake, Ga3+ released from MON acts as a "Trojan horse" to disrupt bacterial iron respiration, effectively inactivating multiple microbes. Moreover, CP cloaks endow MON with reduced immune clearance by masquerading as normal host-tissue molecules, significantly increasing residence time in lung tissue for enhanced antimicrobial efficacy. In multiple lung cancer mice models, microbe-induced drug degradation is remarkably inhibited when drugs are delivered by antimicrobial MON. Tumor growth is sufficiently suppressed and mouse survival is prolonged. The work develops a novel microbiota-depleted nanostrategy to overcome chemoresistance in lung cancer by inhibiting local microbial inactivation of therapeutic drugs.
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Affiliation(s)
- Zi-Yi Han
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Qi-Wen Chen
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Di-Wei Zheng
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Ke-Wei Chen
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Qian-Xiao Huang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Ze-Nan Zhuang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
| | - Xian-Zheng Zhang
- Key Laboratory of Biomedical Polymers of Ministry of Education & Department of Chemistry, Wuhan University, Wuhan, 430072, P. R. China
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Palusiak A. Proteus mirabilis and Klebsiella pneumoniae as pathogens capable of causing co-infections and exhibiting similarities in their virulence factors. Front Cell Infect Microbiol 2022; 12:991657. [PMID: 36339335 PMCID: PMC9630907 DOI: 10.3389/fcimb.2022.991657] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/03/2022] [Indexed: 09/23/2023] Open
Abstract
The genera Klebsiella and Proteus were independently described in 1885. These Gram-negative rods colonize the human intestinal tract regarded as the main reservoir of these opportunistic pathogens. In favorable conditions they cause infections, often hospital-acquired ones. The activity of K. pneumoniae and P. mirabilis, the leading pathogens within each genus, results in infections of the urinary (UTIs) and respiratory tracts, wounds, bacteremia, affecting mainly immunocompromised patients. P. mirabilis and K. pneumoniae cause polymicrobial UTIs, which are often persistent due to the catheter biofilm formation or increasing resistance of the bacteria to antibiotics. In this situation a need arises to find the antigens with features common to both species. Among many virulence factors produced by both pathogens urease shows some structural similarities but the biggest similarities have been observed in lipids A and the core regions of lipopolysaccharides (LPSs). Both species produce capsular polysaccharides (CPSs) but only in K. pneumoniae these antigens play a crucial role in the serological classification scheme, which in Proteus spp. is based on the structural and serological diversity of LPS O-polysaccharides (OPSs). Structural and serological similarities observed for Klebsiella spp. and Proteus spp. polysaccharides are important in the search for the cross-reacting vaccine antigens.
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Affiliation(s)
- Agata Palusiak
- Laboratory of General Microbiology, Department of Biology of Bacteria, Institute of Microbiology, Biotechnology and Immunology, University of Łódź, Łódź, Poland
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Song X, Cui W, Meng F, Xia Q, Li X, Hou M, Jia L, Zhang J. Glucopyranose from Pleurotus geesteranus prevent alcoholic liver diseases by regulating Nrf2/HO-1-TLR4/NF-κB signalling pathways and gut microbiota. Food Funct 2022; 13:2441-2455. [PMID: 35048917 DOI: 10.1039/d1fo03486c] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This study investigated the effects of PGPs (Pleurotus geesteranus polysaccharides), a glucopyranose isolated from the mycelium of Pleurotus geesteranus and characterized with the main chain of →4)-α-D-Glcp-(1→, on the prevention against alcohol liver diseases (ALD), with the aim of providing a theoretical basis for the application of P. geesteranus as prebiotic agents in preventing and treating gut dysbiosis and alcohol-related metabolic disorders in individuals with ALD. The results showed that PGP treatment reduced oxidative stress by up-regulating the Nrf2/HO-1 signalling pathways, and decreased the pro-inflammatory factors by down-regulating TLR4/NF-κB signalling pathways. Furthermore, we validated effects of PGPs on balancing the gut-liver axis by maintaining the integrity of the intestinal epithelial barrier of decreasing intestinal permeability, increasing intestinal tight-junction protein and mucin expression and elevating the abundance of short-chain fatty acids (SCFAs) producers in the intestine by regulating the microbiota composition.
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Affiliation(s)
- Xinling Song
- College of Life Science, Shandong Agricultural University, Taian, 271018, PR China.
| | - Weijun Cui
- College of Life Science, Shandong Agricultural University, Taian, 271018, PR China.
| | - Fanyun Meng
- Xintai Science and Technology Bureau, Taian, 271000, PR China
| | - Qun Xia
- Xintai Science and Technology Bureau, Taian, 271000, PR China
| | - Xueping Li
- College of Life Science, Shandong Agricultural University, Taian, 271018, PR China.
| | - Minjie Hou
- College of Life Science, Shandong Agricultural University, Taian, 271018, PR China.
| | - Le Jia
- College of Life Science, Shandong Agricultural University, Taian, 271018, PR China.
| | - Jianjun Zhang
- College of Life Science, Shandong Agricultural University, Taian, 271018, PR China.
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4
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Rice CJ, Kelly SA, O’Brien SC, Melaugh EM, Ganacias JCB, Chai ZH, Gilmore BF, Skvortsov T. Novel Phage-Derived Depolymerase with Activity against Proteus mirabilis Biofilms. Microorganisms 2021; 9:2172. [PMID: 34683494 PMCID: PMC8539402 DOI: 10.3390/microorganisms9102172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/18/2022] Open
Abstract
The adherence of Proteus mirabilis to the surface of urinary catheters leads to colonization and eventual blockage of the catheter lumen by unique crystalline biofilms produced by these opportunistic pathogens, making P. mirabilis one of the leading causes of catheter-associated urinary tract infections. The Proteus biofilms reduce efficiency of antibiotic-based treatment, which in turn increases the risk of antibiotic resistance development. Bacteriophages and their enzymes have recently become investigated as alternative treatment options. In this study, a novel Proteus bacteriophage (vB_PmiS_PM-CJR) was isolated from an environmental sample and fully characterized. The phage displayed depolymerase activity and the subsequent genome analysis revealed the presence of a pectate lyase domain in its tail spike protein. The protein was heterologously expressed and purified; the ability of the purified tail spike to degrade Proteus biofilms was tested. We showed that the application of the tail spike protein was able to reduce the adherence of bacterial biofilm to plastic pegs in a MBEC (minimum biofilm eradication concentration) assay and improve the survival of Galleria mellonella larvae infected with Proteus mirabilis. Our study is the first to successfully isolate and characterize a biofilm depolymerase from a Proteus phage, demonstrating the potential of this group of enzymes in treatment of Proteus infections.
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Affiliation(s)
| | | | | | | | | | | | | | - Timofey Skvortsov
- School of Pharmacy, Queen’s University Belfast, Belfast BT9 7BL, UK; (C.J.R.); (S.A.K.); (S.C.O.); (E.M.M.); (J.C.B.G.); (Z.H.C.); (B.F.G.)
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Siddharth T, Sridhar P, Vinila V, Tyagi RD. Environmental applications of microbial extracellular polymeric substance (EPS): A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 287:112307. [PMID: 33798774 DOI: 10.1016/j.jenvman.2021.112307] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 02/08/2021] [Accepted: 02/28/2021] [Indexed: 05/06/2023]
Abstract
During the last decade, water demand and wastewater generation has increased due to urbanization around the globe which had led to an increase in the utilization of chemicals/synthetic polymers for treating the wastewaters. These synthetic polymers used during the coagulation/flocculation process are non-renewable, non-biodegradable, and have a potential neurotoxic and carcinogenic effect. From the literature it is clear that extracellular polymer substance (EPS) is a potential bioflocculant, moreover it is renewable, biodegradable, eco-friendly, non-toxic as well as economically valued product. The various identification techniques and extraction methods of EPS are elaborated. Further application of EPS as absorbent in removing the dye from the industrial effluent is presented. Moreover EPS as a potential adsorbent for heavy metal removal from the various effluent is discussed. In addition, EPS is also utilized for soil remediation and soil erosion control. Mainly, EPS as bioflocculant in treating raw water, wastewater treatment, leachate and sludge management are summarized in this review.
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Affiliation(s)
- T Siddharth
- Water and Environment Division, Department of Civil Engineering National Institute of Technology - Warangal, Telangana, India
| | - P Sridhar
- Water and Environment Division, Department of Civil Engineering National Institute of Technology - Warangal, Telangana, India.
| | - V Vinila
- Water and Environment Division, Department of Civil Engineering National Institute of Technology - Warangal, Telangana, India
| | - R D Tyagi
- Chief Scientific Officer, BOSK Bioproducts, Canada
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Vinnitskiy DZ, Ustyuzhanina NE, Nifantiev NE. Natural bacterial and plant biomolecules bearing α-d-glucuronic acid residues. Russ Chem Bull 2016. [DOI: 10.1007/s11172-015-1010-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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7
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Bartley SN, Tzeng YL, Heel K, Lee CW, Mowlaboccus S, Seemann T, Lu W, Lin YH, Ryan CS, Peacock C, Stephens DS, Davies JK, Kahler CM. Attachment and invasion of Neisseria meningitidis to host cells is related to surface hydrophobicity, bacterial cell size and capsule. PLoS One 2013; 8:e55798. [PMID: 23405216 PMCID: PMC3566031 DOI: 10.1371/journal.pone.0055798] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 01/04/2013] [Indexed: 12/13/2022] Open
Abstract
We compared exemplar strains from two hypervirulent clonal complexes, strain NMB-CDC from ST-8/11 cc and strain MC58 from ST-32/269 cc, in host cell attachment and invasion. Strain NMB-CDC attached to and invaded host cells at a significantly greater frequency than strain MC58. Type IV pili retained the primary role for initial attachment to host cells for both isolates regardless of pilin class and glycosylation pattern. In strain MC58, the serogroup B capsule was the major inhibitory determinant affecting both bacterial attachment to and invasion of host cells. Removal of terminal sialylation of lipooligosaccharide (LOS) in the presence of capsule did not influence rates of attachment or invasion for strain MC58. However, removal of either serogroup B capsule or LOS sialylation in strain NMB-CDC increased bacterial attachment to host cells to the same extent. Although the level of inhibition of attachment by capsule was different between these strains, the regulation of the capsule synthesis locus by the two-component response regulator MisR, and the level of surface capsule determined by flow cytometry were not significantly different. However, the diplococci of strain NMB-CDC were shown to have a 1.89-fold greater surface area than strain MC58 by flow cytometry. It was proposed that the increase in surface area without changing the amount of anchored glycolipid capsule in the outer membrane would result in a sparser capsule and increase surface hydrophobicity. Strain NMB-CDC was shown to be more hydrophobic than strain MC58 using hydrophobicity interaction chromatography and microbial adhesion-to-solvents assays. In conclusion, improved levels of adherence of strain NMB-CDC to cell lines was associated with increased bacterial cell surface and surface hydrophobicity. This study shows that there is diversity in bacterial cell surface area and surface hydrophobicity within N. meningitidis which influence steps in meningococcal pathogenesis.
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Affiliation(s)
- Stephanie N. Bartley
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Yih-Ling Tzeng
- Veterans Affairs Medical Center, Atlanta, Georgia, United States of America
- Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Kathryn Heel
- Centre for Microscopy, Characterisation and Analysis, and Translational Cancer Pathology Laboratory, School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Chiang W. Lee
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Shakeel Mowlaboccus
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Torsten Seemann
- Victorian Bioinformatics Consortium, Monash University, Melbourne, Victoria, Australia
| | - Wei Lu
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Ya-Hsun Lin
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Catherine S. Ryan
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Christopher Peacock
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - David S. Stephens
- Veterans Affairs Medical Center, Atlanta, Georgia, United States of America
- Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - John K. Davies
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Charlene M. Kahler
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Western Australia, Australia
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Hobb RI, Tzeng YL, Choudhury BP, Carlson RW, Stephens DS. Requirement of NMB0065 for connecting assembly and export of sialic acid capsular polysaccharides in Neisseria meningitidis. Microbes Infect 2010; 12:476-87. [PMID: 20215001 PMCID: PMC2883662 DOI: 10.1016/j.micinf.2010.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 02/25/2010] [Accepted: 02/27/2010] [Indexed: 12/20/2022]
Abstract
Capsule expression in Neisseria meningitidis is encoded by the cps locus comprised of genes required for biosynthesis and surface translocation. Located adjacent to the gene encoding the polysialyltransferase in serogroups expressing sialic acid-containing capsule, NMB0065 is likely a member of the cps locus, but it is not found in serogroups A or X that express non-sialic acid capsules. To further understand its role in CPS expression, NMB0065 mutants were created in the serogroups B, C and Y strains. The mutants were as sensitive as unencapsulated strains to killing by normal human serum, despite producing near wild-type levels of CPS. Absence of surface expression of capsule was suggested by increased surface hydrophobicity and confirmed by immunogold electron microscopy, which revealed the presence of large vacuoles containing CPS within the cell. GC-MS and NMR analyses of purified capsule from the mutant revealed no apparent changes in polymer structures and lipid anchors. Mutants of NMB0065 homologues in other sialic acid CPS expressing meningococcal serogroups had similar phenotypes. Thus, NMB0065 (CtrG) is not involved in biosynthesis or lipidation of sialic acid-containing capsule but encodes a protein required for proper coupling of the assembly complex to the membrane transport complex allowing surface expression of CPS.
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Affiliation(s)
- Rhonda I Hobb
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, United States
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9
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Tzeng YL, Datta AK, Strole CA, Lobritz MA, Carlson RW, Stephens DS. Translocation and surface expression of lipidated serogroup B capsular Polysaccharide in Neisseria meningitidis. Infect Immun 2005; 73:1491-505. [PMID: 15731047 PMCID: PMC1064937 DOI: 10.1128/iai.73.3.1491-1505.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The capsule of N. meningitidis serogroup B, (alpha2-->8)-linked polysialic acid and the capsules of other meningococcal serogroups and of other gram-negative bacterial pathogens are anchored in the outer membrane through a 1,2-diacylglycerol moiety. Previous work on the meningococcal cps complex in Escherichia coli K-12 indicated that deletion of genes designated lipA and lipB caused intracellular accumulation of hyperelongated capsule polymers lacking the phospholipid substitution. To better understand the role of lip and lipB in capsule expression in a meningococcal background, the location, sequence, and relationship to related bacterial capsule genes were defined and specific mutations in lipA and lipB were generated in the serogroup B meningococcal strain NMB. The lipA and lipB genes are located on the 3' end of the ctr operon and are most likely transcribed independently. Inactivation of lipA, lipB, and both resulted in the same total levels of capsular polymer production as in the parental controls; however, these mutants were as sensitive as an unencapsulated mutant to killing by normal human serum. Immunogold electron microscopy and flow cytometric analyses revealed intracellular inclusions of capsular polymers in lipA, lipB, and lipA lipB mutants. Capsular polymers purified from lipA, lipB, and lipA lipB mutants were lipidated. The phospholipid anchor was shown by gas chromatography-mass spectroscopy analysis to be a phosphodiester-linked 1,2-dipalmitoyl (C16:0) glycerol moiety and was identical in structure to that found on the wild-type meningococcal capsule polymers. Thus, lipA and lipB do not encode proteins responsible for diacylglycerophosphatidic acid substitution of the meningococcal capsule polymer; rather, they are required for proper translocation and surface expression of the lipidated polymer.
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Affiliation(s)
- Yih-Ling Tzeng
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30033, USA
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10
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Abstract
Glycosyltransferases catalyze the synthesis of glycoconjugates by transferring a properly activated sugar residue to an appropriate acceptor molecule or aglycone for chain initiation and elongation. The acceptor can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. A catalytic reaction is believed to involve the recognition of both the donor and acceptor by suitable domains, as well as the catalytic site of the enzyme. To elucidate the structural requirements for substrate recognition and catalytic reactions of glycosyltransferases, we have searched the databases for homologous sequences, identified conserved amino acid residues, and proposed potential domain motifs for these enzymes. Depending on the configuration of the anomeric functional group of the glycosyl donor molecule and of the resulting glycoconjugate, all known glycosyltransferases can be divided into two major types: retaining glycosyltransferases, which transfer sugar residue with the retention of anomeric configuration, and inverting glycosyltransferases, which transfer sugar residue with the inversion of anomeric configuration. One conserved domain of the inverting glycosyltransferases identified in the database is responsible for the recognition of a pyrimidine nucleotide, which is either the UDP or the TDP portion of a donor sugar-nucleotide molecule. This domain is termed "Nucleotide Recognition Domain 1 beta," or NRD1 beta, since the type of nucleotide is the only common structure among the sugar donors and acceptors. NRD1 beta is present in 140 glycosyltransferases. The central portion of the NRD1 beta domain is very similar to the domain that is present in one family of retaining glycosyltransferases. This family is termed NRD1 alpha to designate the similarity and stereochemistry of sugar transfer, and it consists of 77 glycosyltransferases identified thus far. In the central portion there is a homologous region for these two families and this region probably has a catalytic function. A third conserved domain is found exclusively in membrane-bound glycosyltransferases and is termed NRD2; this domain is present in 98 glycosyltransferases. All three identified NRDs are present in archaebacterial, eubacterial, viral, and eukaryotic glycosyltransferases. The present article presents the alignment of conserved NRD domains and also presents a brief overview of the analyzed glycosyltransferases which comprise about 65% of all known sugar-nucleotide dependent (Leloir-type) and putative glycosyltransferases in different databases. A potential mechanism for the catalytic reaction is also proposed. This proposed mechanism should facilitate the design of experiments to elucidate the regulatory mechanisms of glycosylation reactions. Amino acid sequence information within the conserved domain may be utilized to design degenerate primers for identifying DNA encoding new glycosyltransferases.
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Affiliation(s)
- D Kapitonov
- Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond 23298-0614, USA
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Rahman MM, Guard-Petter J, Asokan K, Hughes C, Carlson RW. The structure of the colony migration factor from pathogenic Proteus mirabilis. A capsular polysaccharide that facilitates swarming. J Biol Chem 1999; 274:22993-8. [PMID: 10438465 DOI: 10.1074/jbc.274.33.22993] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Swarming by Proteus mirabilis is characterized by cycles of rapid and coordinated population migration across surfaces following differentiation of vegetative cells into elongated hyperflagellated swarm cells. It has been shown that surface colony expansion by the swarm cell population is facilitated by a colony migration factor (Cmf), a capsular polysaccharide (CPS) that also contributes to the uropathogenicity of P. mirabilis (Gygi, D., Rahman, M. M., Lai, H.-C., Carlson, R., Guard-Petter, J., and Hughes, C. (1995) Mol. Microbiol. 17, 1167-1175). In this report, the Cmf-CPS was extracted with hot water, precipitated with ethanol, and further purified by gel permeation chromatography. Its structure was established by glycosyl composition and linkage analyses, and by one- and two-dimensional NMR spectroscopy. The Cmf-CPS is composed of the following tetrasaccharide repeating unit. [see text]
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Affiliation(s)
- M M Rahman
- Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602, USA
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12
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Kang Y, Carlson R, Tharpe W, Schell MA. Characterization of genes involved in biosynthesis of a novel antibiotic from Burkholderia cepacia BC11 and their role in biological control of Rhizoctonia solani. Appl Environ Microbiol 1998; 64:3939-47. [PMID: 9758823 PMCID: PMC106582 DOI: 10.1128/aem.64.10.3939-3947.1998] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic manipulation of fluorescent pseudomonads has provided major insight into their production of antifungal molecules and their role in biological control of plant disease. Burkholderia cepacia also produces antifungal activities, but its biological control activity is much less well characterized, in part due to difficulties in applying genetic tools. Here we report genetic and biochemical characterization of a soil isolate of B. cepacia relating to its production of an unusual antibiotic that is very active against a variety of soil fungi. Purification and preliminary structural analyses suggest that this antibiotic (called AFC-BC11) is a novel lipopeptide associated largely with the cell membrane. Analysis of conditions for optimal production of AFC-BC11 indicated stringent environmental regulation of its synthesis. Furthermore, we show that production of AFC-BC11 is largely responsible for the ability of B. cepacia BC11 to effectively control the damping-off of cotton caused by the fungal pathogen Rhizoctonia solani in a gnotobiotic system. Using Tn5 mutagenesis, we identified, cloned, and characterized a region of the genome of strain BC11 that is required for production of this antifungal metabolite. DNA sequence analysis suggested that this region encodes proteins directly involved in the production of a nonribosomally synthesized lipopeptide.
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Affiliation(s)
- Y Kang
- Department of Microbiology, University of Georgia, Athens, Georgia 30602, USA
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