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Santoshi M, Bansia H, Hussain M, Jha AK, Nagaraja V. Identification of a 1-acyl-glycerol-3-phosphate acyltransferase from Mycobacterium tuberculosis, a key enzyme involved in triacylglycerol biosynthesis. Mol Microbiol 2024; 121:1164-1181. [PMID: 38676355 DOI: 10.1111/mmi.15265] [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: 12/30/2023] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024]
Abstract
Latent tuberculosis, caused by dormant Mycobacterium tuberculosis (Mtb), poses a threat to global health through the incubation of undiagnosed infections within the community. Dormant Mtb, which is phenotypically tolerant to antibiotics, accumulates triacylglycerol (TAG) utilizing fatty acids obtained from macrophage lipid droplets. TAG is vital to mycobacteria, serving as a cell envelope component and energy reservoir during latency. TAG synthesis occurs by sequential acylation of glycerol-3-phosphate, wherein the second acylation step is catalyzed by acylglycerol-3-phosphate acyltransferase (AGPAT), resulting in the production of phosphatidic acid (PA), a precursor for the synthesis of TAG and various phospholipids. Here, we have characterized a putative acyltransferase of Mtb encoded by Rv3816c. We found that Rv3816c has all four characteristic motifs of AGPAT, exists as a membrane-bound enzyme, and functions as 1-acylglycerol-3-phosphate acyltransferase. The enzyme could transfer the acyl group to acylglycerol-3-phosphate (LPA) from monounsaturated fatty acyl-coenzyme A of chain length 16 or 18 to produce PA. Complementation of Escherichia coli PlsC mutant in vivo by Rv3816c confirmed that it functions as AGPAT. Its active site mutants, H43A and D48A, were incapable of transferring the acyl group to LPA in vitro and were not able to rescue the growth defect of E. coli PlsC mutant in vivo. Identifying Rv3816c as AGPAT and comparing its properties with other AGPAT homologs is not only a step toward understanding the TAG biosynthesis in mycobacteria but has the potential to explore it as a drug target.
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Affiliation(s)
- Meghna Santoshi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Harsh Bansia
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Muzammil Hussain
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Abodh Kumar Jha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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2
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Vasilopoulos G, Heflik L, Czolkoss S, Heinrichs F, Kleetz J, Yesilyurt C, Tischler D, Westhoff P, Exterkate M, Aktas M, Narberhaus F. Characterization of multiple lysophosphatidic acid acyltransferases in the plant pathogen Xanthomonas campestris. FEBS J 2024; 291:705-721. [PMID: 37943159 DOI: 10.1111/febs.16996] [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: 02/20/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 11/10/2023]
Abstract
Phosphatidic acid (PA) is the precursor of most phospholipids like phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. In bacteria, its biosynthesis begins with the acylation of glycerol-3-phosphate to lysophosphatidic acid (LPA), which is further acylated to PA by the PlsC enzyme. Some bacteria, like the plant pathogen Xanthomonas campestris, use a similar pathway to acylate lysophosphatidylcholine to phosphatidylcholine (PC). Previous studies assigned two acyltransferases to PC formation. Here, we set out to study their activity and found a second much more prominent function of these enzymes in LPA to PA conversion. This PlsC-like activity was supported by the functional complementation of a temperature-sensitive plsC-deficient Escherichia coli strain. Biocomputational analysis revealed two further PlsC homologs in X. campestris. The cellular levels of the four PlsC-like proteins varied with respect to growth phase and growth temperature. To address the question whether these enzymes have redundant or specific functions, we purified two recombinant, detergent-solubilized enzymes in their active form, which enabled the first direct biochemical comparison of PlsC isoenzymes from the same organism. Overlapping but not identical acyl acceptor and acyl donor preferences suggest redundant and specialized functions of the X. campestris PlsC enzymes. The altered fatty acid composition in plsC mutant strains further supports the functional differentiation of these enzymes.
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Affiliation(s)
- Georgios Vasilopoulos
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Lukas Heflik
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Simon Czolkoss
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Florian Heinrichs
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Julia Kleetz
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Cansel Yesilyurt
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Dirk Tischler
- Faculty of Biology and Biotechnology, Microbial Biotechnology, Ruhr University Bochum, Germany
| | - Philipp Westhoff
- Metabolomics and Metabolism Laboratory, Cluster of Excellence for Plant Sciences (CEPLAS), Heinrich Heine University Düsseldorf, Germany
| | - Marten Exterkate
- Faculty of Mathematics and Natural Sciences, Membrane Biogenesis and Lipidomics, Institute of Biochemistry, Heinrich Heine University Düsseldorf, Germany
| | - Meriyem Aktas
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
| | - Franz Narberhaus
- Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Germany
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3
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Ogawa T, Kuboshima M, Suwanawat N, Kawamoto J, Kurihara T. Division of the role and physiological impact of multiple lysophosphatidic acid acyltransferase paralogs. BMC Microbiol 2022; 22:241. [PMID: 36203164 PMCID: PMC9541089 DOI: 10.1186/s12866-022-02641-8] [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: 06/14/2022] [Accepted: 09/13/2022] [Indexed: 11/10/2022] Open
Abstract
Background Lysophosphatidic acid acyltransferase (LPAAT) is a phospholipid biosynthesis enzyme that introduces a particular set of fatty acids at the sn-2 position of phospholipids. Many bacteria have multiple LPAAT paralogs, and these enzymes are considered to have different fatty acid selectivities and to produce diverse phospholipids with distinct fatty acid compositions. This feature is advantageous for controlling the physicochemical properties of lipid membranes to maintain membrane integrity in response to the environment. However, it remains unclear how LPAAT paralogs are functionally differentiated and biologically significant. Results To better understand the division of roles of the LPAAT paralogs, we analyzed the functions of two LPAAT paralogs, PlsC4 and PlsC5, from the psychrotrophic bacterium Shewanella livingstonensis Ac10. As for their enzymatic function, lipid analysis of plsC4- and plsC5-inactivated mutants revealed that PlsC4 prefers iso-tridecanoic acid (C12-chain length, methyl-branched), whereas PlsC5 prefers palmitoleic acid (C16-chain length, monounsaturated). Regarding the physiological role, we found that plsC4, not plsC5, contributes to tolerance to cold stress. Using bioinformatics analysis, we demonstrated that orthologs of PlsC4/PlsC5 and their close relatives, constituting a new clade of LPAATs, are present in many γ-proteobacteria. We also found that LPAATs of this clade are phylogenetically distant from principal LPAATs, such as PlsC1 of S. livingstonensis Ac10, which are universally conserved among bacteria, suggesting the presence of functionally differentiated LPAATs in these bacteria. Conclusions PlsC4 and PlsC5, which are LPAAT paralogs of S. livingstonensis Ac10, play different roles in phospholipid production and bacterial physiology. An enzyme belonging to PlsC4/PlsC5 subfamilies and their close relatives are present, in addition to principal LPAATs, in many γ-proteobacteria, suggesting that the division of roles is more common than previously thought. Thus, both principal LPAATs and PlsC4/PlsC5-related enzymes should be considered to decipher the metabolism and physiology of bacterial cell membranes. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02641-8.
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Affiliation(s)
- Takuya Ogawa
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Misaki Kuboshima
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Nittikarn Suwanawat
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
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4
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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Ogawa T, Suwanawat N, Toyotake Y, Watanabe B, Kawamoto J, Kurihara T. Lysophosphatidic acid acyltransferase from the thermophilic bacterium Thermus thermophilus HB8 displays substrate promiscuity. Biosci Biotechnol Biochem 2020; 84:1831-1838. [PMID: 32456605 DOI: 10.1080/09168451.2020.1771169] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Lysophosphatidic acid acyltransferase is a phospholipid biosynthetic enzyme that introduces a fatty acyl group into the sn-2 position of phospholipids. Its substrate selectivity is physiologically important in defining the physicochemical properties of lipid membranes and modulating membrane protein function. However, it remains unclear how these enzymes recognize various fatty acids. Successful purification of bacterial lysophosphatidic acid acyltransferases (PlsCs) was recently reported and has paved a path for the detailed analysis of their reaction mechanisms. Here, we purified and characterized PlsC from the thermophilic bacterium Thermus thermophilus HB8. This integral membrane protein remained active even after solubilization and purification and showed reactivity toward saturated, unsaturated, and methyl-branched fatty acids, although branched-chain acyl groups are the major constituent of phospholipids of this bacterium. Multiple sequence alignment revealed the N-terminal end of the enzyme to be shorter than that of PlsCs with defined substrate selectivity, suggesting that the shortened N-terminus confers substrate promiscuity. ABBREVIATIONS ACP: acyl carrier protein; CAPS: N-cyclohexyl-3-aminopropanesulfonic acid; CoA: coenzyme A; CYMAL-6: 6-cyclohexyl-1-hexyl-β-D-maltoside; DDM: n-dodecyl-β-D-maltoside; DTNB: 5,5´-dithiobis(2-nitrobenzoic acid); EPA: eicosapentaenoic acid; G3P: glycerol 3-phosphate; HEPES: N-2-hydroxyethylpiperazine-N´-2-ethanesulfonic acid; LPA: lysophosphatidic acid; MS: mass spectrometry; PA: phosphatidic acid.
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Affiliation(s)
- Takuya Ogawa
- Institute for Chemical Research, Kyoto University , Kyoto, Japan
| | | | - Yosuke Toyotake
- Institute for Chemical Research, Kyoto University , Kyoto, Japan
| | - Bunta Watanabe
- Institute for Chemical Research, Kyoto University , Kyoto, Japan
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University , Kyoto, Japan
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University , Kyoto, Japan
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6
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Toyotake Y, Nishiyama M, Yokoyama F, Ogawa T, Kawamoto J, Kurihara T. A Novel Lysophosphatidic Acid Acyltransferase of Escherichia coli Produces Membrane Phospholipids with a cis-vaccenoyl Group and Is Related to Flagellar Formation. Biomolecules 2020; 10:E745. [PMID: 32403425 PMCID: PMC7277886 DOI: 10.3390/biom10050745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/02/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023] Open
Abstract
Lysophosphatidic acid acyltransferase (LPAAT) introduces fatty acyl groups into the sn-2 position of membrane phospholipids (PLs). Various bacteria produce multiple LPAATs, whereas it is believed that Escherichia coli produces only one essential LPAAT homolog, PlsC-the deletion of which is lethal. However, we found that E. coli possesses another LPAAT homolog named YihG. Here, we show that overexpression of YihG in E. coli carrying a temperature-sensitive mutation in plsC allowed its growth at non-permissive temperatures. Analysis of the fatty acyl composition of PLs from the yihG-deletion mutant (∆yihG) revealed that endogenous YihG introduces the cis-vaccenoyl group into the sn-2 position of PLs. Loss of YihG did not affect cell growth or morphology, but ∆yihG cells swam well in liquid medium in contrast to wild-type cells. Immunoblot analysis showed that FliC was highly expressed in ∆yihG cells, and this phenotype was suppressed by expression of recombinant YihG in ∆yihG cells. Transmission electron microscopy confirmed that the flagellar structure was observed only in ∆yihG cells. These results suggest that YihG has specific functions related to flagellar formation through modulation of the fatty acyl composition of membrane PLs.
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Affiliation(s)
- Yosuke Toyotake
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
| | - Masayoshi Nishiyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Fumiaki Yokoyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Takuya Ogawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan; (Y.T.); (M.N.); (F.Y.); (T.O.); (J.K.)
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7
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Ogawa T, Tanaka A, Kawamoto J, Kurihara T. Purification and characterization of 1-acyl-sn-glycerol-3-phosphate acyltransferase with a substrate preference for polyunsaturated fatty acyl donors from the eicosapentaenoic acid-producing bacterium Shewanella livingstonensis Ac10. J Biochem 2018; 164:33-39. [PMID: 29415144 DOI: 10.1093/jb/mvy025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/21/2018] [Indexed: 11/12/2022] Open
Abstract
1-Acyl-sn-glycerol-3-phosphate acyltransferase (designated as PlsC in bacteria) catalyzes the acylation of lysophosphatidic acid and is responsible for the de novo production of phosphatidic acid, a precursor for the synthesis of various membrane glycerophospholipids. Because PlsC is an integral membrane protein, it is generally difficult to solubilize it without causing its inactivation, which has been hampering its biochemical characterization despite its ubiquitous presence and physiological importance. Most biochemical studies of PlsC have been carried out using crude membrane preparations or intact cells. In this study, we succeeded in solubilization and purification of a recombinant PlsC in its active form from the eicosapentaenoic acid-producing bacterium Shewanella livingstonensis Ac10 using 6-cyclohexyl-1-hexyl-β-d-maltoside as the detergent. We characterized the purified enzyme and found that it has a substrate preference for the acyl donors with a polyunsaturated fatty acyl group, such as eicosapentaenoyl group. These results provide a new method for purification of the PlsC family enzyme and demonstrate the occurrence of a new PlsC with unique substrate specificity.
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Affiliation(s)
- Takuya Ogawa
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Asako Tanaka
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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8
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Barriuso J, Martínez MJ. In Silico Analysis of the Quorum Sensing Metagenome in Environmental Biofilm Samples. Front Microbiol 2018; 9:1243. [PMID: 29930547 PMCID: PMC6000730 DOI: 10.3389/fmicb.2018.01243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/23/2018] [Indexed: 01/09/2023] Open
Abstract
Quorum sensing (QS) is a sophisticated cell to cell signaling mechanism mediated by small diffusible molecules called “autoinducers.” This phenomenon is well studied in bacteria, where different QS systems are described that differ between Gram-negative and Gram-positive bacteria. However, a common system to these groups was discovered, the autoinducer 2. QS has implications in biofilm formation, where the application of metagenomic techniques to study these phenomena may be useful to understand the communication networks established by the different components of the community, and to discover new targets for microbial control. Here we present an in silico screening of QS proteins in all publicly available biofilm metagenomes from the JGI database. We performed sequence, conserved motifs, phylogenetic, and three-dimensional structure analyses of the candidates, resulting in an effective strategy to search QS proteins in metagenomes sequences. The number of QS proteins present in each sample, and its phylogenetic affiliation, was clearly related to the bacterial diversity and the origin of the biofilm. The samples isolated from natural habitats presented clear differences with those from artificial habitats. Interesting findings have been made in the abundance of LuxR-like proteins finding an unbalanced ratio between the synthases and the receptor proteins in Bacteroidetes bacteria, pointing out the existence of “cheaters” in this group. Moreover, we have shown the presence of the LuxI/R QS system in bacteria from the Nitrospira taxonomic group. Finally, some undescribed proteins from the HdtS family have been found in Gamma-proteobacteria.
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Affiliation(s)
- Jorge Barriuso
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - María J Martínez
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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9
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Toyotake Y, Cho HN, Kawamoto J, Kurihara T. A novel 1-acyl-sn-glycerol-3-phosphate O-acyltransferase homolog for the synthesis of membrane phospholipids with a branched-chain fatty acyl group in Shewanella livingstonensis Ac10. Biochem Biophys Res Commun 2018; 500:704-709. [PMID: 29678574 DOI: 10.1016/j.bbrc.2018.04.140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 04/17/2018] [Indexed: 12/21/2022]
Abstract
1-Acyl-sn-glycerol-3-phosphate O-acyltransferase (PlsC) plays an essential role in the formation of phosphatidic acid, a precursor of various membrane phospholipids (PLs), in bacteria by catalyzing the introduction of an acyl group into the sn-2 position of lysophosphatidic acid. Various bacteria produce more than one PlsC. However, the physiological significance of the occurrence of multiple PlsCs is poorly understood. A psychrotrophic bacterium, Shewanella livingstonensis Ac10, which produces eicosapentaenoic acid at low temperatures, has five putative PlsCs (PlsC1-5). We previously showed that PlsC1 is responsible for the production of PLs containing an eicosapentaenoyl group. Here, we characterized another putative PlsC of this bacterium named PlsC4. We generated a plsC4-disrupted mutant and found that PLs containing 13:0 found in the parental strain were almost completely absent in the mutant. The loss of these PLs was suppressed by introduction of a plsC4-expression plasmid. PLs containing 15:0 were also drastically decreased by plsC4 disruption. Gas chromatography-mass spectrometry analysis of fatty acyl methyl esters derived from PLs of the parental strain showed that the 13:0 and 15:0 groups were an 11-methyllauroyl group and a 13-methylmyristoyl group, respectively. Phospholipase A2 treatment revealed that these fatty acyl groups were linked to the sn-2 position of PLs. Thus, PlsC4 is a new type of PlsC homolog that is responsible for the synthesis of PLs containing a branched-chain fatty acyl group at the sn-2 position and plays a clearly different role from that of PlsC1 in vivo.
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Affiliation(s)
- Yosuke Toyotake
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hyun-Nam Cho
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Jun Kawamoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tatsuo Kurihara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
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10
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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.
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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
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11
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Yao J, Bruhn DF, Frank MW, Lee RE, Rock CO. Activation of Exogenous Fatty Acids to Acyl-Acyl Carrier Protein Cannot Bypass FabI Inhibition in Neisseria. J Biol Chem 2015; 291:171-81. [PMID: 26567338 DOI: 10.1074/jbc.m115.699462] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Indexed: 11/06/2022] Open
Abstract
Neisseria is a Gram-negative pathogen with phospholipids composed of straight chain saturated and monounsaturated fatty acids, the ability to incorporate exogenous fatty acids, and lipopolysaccharides that are not essential. The FabI inhibitor, AFN-1252, was deployed as a chemical biology tool to determine whether Neisseria can bypass the inhibition of fatty acid synthesis by incorporating exogenous fatty acids. Neisseria encodes a functional FabI that was potently inhibited by AFN-1252. AFN-1252 caused a dose-dependent inhibition of fatty acid synthesis in growing Neisseria, a delayed inhibition of growth phenotype, and minimal inhibition of DNA, RNA, and protein synthesis, showing that its mode of action is through inhibiting fatty acid synthesis. Isotopic fatty acid labeling experiments showed that Neisseria encodes the ability to incorporate exogenous fatty acids into its phospholipids by an acyl-acyl carrier protein-dependent pathway. However, AFN-1252 remained an effective antibacterial when Neisseria were supplemented with exogenous fatty acids. These results demonstrate that extracellular fatty acids are activated by an acyl-acyl carrier protein synthetase (AasN) and validate type II fatty acid synthesis (FabI) as a therapeutic target against Neisseria.
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Affiliation(s)
| | - David F Bruhn
- Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | | | - Richard E Lee
- Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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Vanoirbeek K, Aertsen A, Michiels CW. Role of 1-acyl-sn-glycerol-3-phosphate acyltransferase in psychrotrophy and stress tolerance of Serratia plymuthica RVH1. Res Microbiol 2014; 166:28-37. [PMID: 25446612 DOI: 10.1016/j.resmic.2014.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 11/19/2022]
Abstract
A mutant with a transposon insertion just upstream of the lysophosphatidic acid acyltansferase gene plsC was isolated in a screen for mutants affected in growth at low temperature of the psychrotroph Serratia plymuthica RVH1. This mutant had lost its ability to grow at 4 °C and was severely affected in growth at 10 °C, but showed only slightly reduced growth at 30 °C. Fatty acid analysis of membrane extracts showed that the ratio of C16:1/C18:1 fatty acids was six-to sevenfold reduced in the mutant, although the ratio of unsaturated to saturated fatty acids was unaffected. The homeoviscous adaptation ability of the mutant was also unaffected. Growth and fatty acid composition were mostly restored by overexpressing plsC on a plasmid. Supplementation of C16:1 (palmitoleic acid) into the growth medium partially rescued low temperature growth, indicating that a balanced ratio of the two main unsaturated fatty acids is required for psychrotrophy. The mutant was significantly more strongly inactivated by high pressure treatment at 250 MPa, but not at higher pressures. It also showed reduced growth at low pH, but not at increased NaCl concentrations. This work provides novel information on the role of membrane fatty acid composition in stress tolerance.
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Affiliation(s)
- Kristof Vanoirbeek
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Center (LFoRCe), Department of Microbial and Molecular Systems (M(2)S), Faculty of Bioscience Engineering, KU Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium.
| | - Abram Aertsen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Center (LFoRCe), Department of Microbial and Molecular Systems (M(2)S), Faculty of Bioscience Engineering, KU Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium.
| | - Chris W Michiels
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Center (LFoRCe), Department of Microbial and Molecular Systems (M(2)S), Faculty of Bioscience Engineering, KU Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium.
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Phosphatidic acid synthesis in bacteria. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:495-502. [PMID: 22981714 DOI: 10.1016/j.bbalip.2012.08.018] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/21/2012] [Accepted: 08/23/2012] [Indexed: 12/15/2022]
Abstract
Membrane phospholipid synthesis is a vital facet of bacterial physiology. Although the spectrum of phospholipid headgroup structures produced by bacteria is large, the key precursor to all of these molecules is phosphatidic acid (PtdOH). Glycerol-3-phosphate derived from the glycolysis via glycerol-phosphate synthase is the universal source for the glycerol backbone of PtdOH. There are two distinct families of enzymes responsible for the acylation of the 1-position of glycerol-3-phosphate. The PlsB acyltransferase was discovered in Escherichia coli, and homologs are present in many eukaryotes. This protein family primarily uses acyl-acyl carrier protein (ACP) endproducts of fatty acid synthesis as acyl donors, but may also use acyl-CoA derived from exogenous fatty acids. The second protein family, PlsY, is more widely distributed in bacteria and utilizes the unique acyl donor, acyl-phosphate, which is produced from acyl-ACP by the enzyme PlsX. The acylation of the 2-position is carried out by members of the PlsC protein family. All PlsCs use acyl-ACP as the acyl donor, although the PlsCs of the γ-proteobacteria also may use acyl-CoA. Phospholipid headgroups are precursors in the biosynthesis of other membrane-associated molecules and the diacylglycerol product of these reactions is converted to PtdOH by one of two distinct families of lipid kinases. The central importance of the de novo and recycling pathways to PtdOH in cell physiology suggest that these enzymes are suitable targets for the development of antibacterial therapeutics in Gram-positive pathogens. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Mair E A Churchill
- Department of Pharmacology and Program in Structural Biology and Biophysics, The University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
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Geiger O, González-Silva N, López-Lara IM, Sohlenkamp C. Amino acid-containing membrane lipids in bacteria. Prog Lipid Res 2010; 49:46-60. [DOI: 10.1016/j.plipres.2009.08.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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A shotgun lipidomics study of a putative lysophosphatidic acid acyl transferase (PlsC) in Sinorhizobium meliloti. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:2873-82. [DOI: 10.1016/j.jchromb.2009.05.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 05/05/2009] [Accepted: 05/09/2009] [Indexed: 02/04/2023]
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17
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Six DA, Carty SM, Guan Z, Raetz CRH. Purification and mutagenesis of LpxL, the lauroyltransferase of Escherichia coli lipid A biosynthesis. Biochemistry 2008; 47:8623-37. [PMID: 18656959 DOI: 10.1021/bi800873n] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Escherichia coli lipid A is a hexaacylated disaccharide of glucosamine with secondary laurate and myristate chains on the distal unit. Hexaacylated lipid A is a potent agonist of human Toll-like receptor 4, whereas its tetra- and pentaacylated precursors are antagonists. The inner membrane enzyme LpxL transfers laurate from lauroyl-acyl carrier protein to the 2'- R-3-hydroxymyristate moiety of the tetraacylated lipid A precursor Kdo 2-lipid IV A. LpxL has now been overexpressed, solubilized with n-dodecyl beta- d-maltopyranoside (DDM), and purified to homogeneity. LpxL migration on a gel filtration column is consistent with a molecular mass of 80 kDa, suggestive of an LpxL monomer (36 kDa) embedded in a DDM micelle. Mass spectrometry showed that deformylated LpxL was the predominant species, noncovalently bound to as many as 12 DDM molecules. Purified LpxL catalyzed not only the formation in vitro of Kdo 2-(lauroyl)-lipid IV A but also a slow second acylation, generating Kdo 2-(dilauroyl)-lipid IV A. Consistent with the Kdo dependence of crude LpxL in membranes, Kdo 2-lipid IV A is preferred 6000-fold over lipid IV A by the pure enzyme. Sequence comparisons suggest that LpxL shares distant homology with the glycerol-3-phosphate acyltransferase (GPAT) family, including a putative catalytic dyad located in a conserved H(X) 4D/E motif. Mutation of H132 or E137 to alanine reduces specific activity by over 3 orders of magnitude. Like many GPATs, LpxL can also utilize acyl-CoA as an alternative acyl donor, albeit at a slower rate. Our results show that the acyltransferases that generate the secondary acyl chains of lipid A are members of the GPAT family and set the stage for structural studies.
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Affiliation(s)
- David A Six
- Department of Biochemistry, Duke University Medical Center, P.O. Box 3711, Durham, North Carolina 27710, USA
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Zhang YM, Rock CO. Thematic review series: Glycerolipids. Acyltransferases in bacterial glycerophospholipid synthesis. J Lipid Res 2008; 49:1867-74. [PMID: 18369234 DOI: 10.1194/jlr.r800005-jlr200] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phospholipid biosynthesis is a vital facet of bacterial physiology that begins with the synthesis of the fatty acids by a soluble type II fatty acid synthase. The bacterial glycerol-phosphate acyltransferases utilize the completed fatty acid chains to form the first membrane phospholipid and thus play a critical role in the regulation of membrane biogenesis. The first bacterial acyltransferase described was PlsB, a glycerol-phosphate acyltransferase. PlsB is a key regulatory point that coordinates membrane phospholipid formation with cell growth and macromolecular synthesis. Phosphatidic acid is then produced by PlsC, a 1-acylglycerol-phosphate acyltransferase. These two acyltransferases use thioesters of either CoA or acyl carrier protein (ACP) as the acyl donors and have homologs that perform the same reactions in higher organisms. However, the most prevalent glycerol-phosphate acyltransferase in the bacterial world is PlsY, which uses a recently discovered acyl-phosphate fatty acid intermediate as an acyl donor. This unique activated fatty acid is formed from the acyl-ACP end products of the fatty acid biosynthetic pathway by PlsX, an acyl-ACP:phosphate transacylase.
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Affiliation(s)
- Yong-Mei Zhang
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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Rhodobacter capsulatus OlsA is a bifunctional enzyme active in both ornithine lipid and phosphatidic acid biosynthesis. J Bacteriol 2007; 189:8564-74. [PMID: 17921310 DOI: 10.1128/jb.01121-07] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Rhodobacter capsulatus genome contains three genes (olsA [plsC138], plsC316, and plsC3498) that are annotated as lysophosphatidic acid (1-acyl-sn-glycerol-3-phosphate) acyltransferase (AGPAT). Of these genes, olsA was previously shown to be an O-acyltransferase in the second step of ornithine lipid biosynthesis, which is important for optimal steady-state levels of c-type cytochromes (S. Aygun-Sunar, S. Mandaci, H.-G. Koch, I. V. J. Murray, H. Goldfine, and F. Daldal. Mol. Microbiol. 61:418-435, 2006). The roles of the remaining plsC316 and plsC3498 genes remained unknown. In this work, these genes were cloned, and chromosomal insertion-deletion mutations inactivating them were obtained to define their function. Characterization of these mutants indicated that, unlike the Escherichia coli plsC, neither plsC316 nor plsC3498 was essential in R. capsulatus. In contrast, no plsC316 olsA double mutant could be isolated, indicating that an intact copy of either olsA or plsC316 was required for R. capsulatus growth under the conditions tested. Compared to OlsA null mutants, PlsC316 null mutants contained ornithine lipid and had no c-type cytochrome-related phenotype. However, they exhibited slight growth impairment and highly altered total fatty acid and phospholipid profiles. Heterologous expression in an E. coli plsC(Ts) mutant of either R. capsulatus plsC316 or olsA gene products supported growth at a nonpermissive temperature, exhibited AGPAT activity in vitro, and restored phosphatidic acid biosynthesis. The more vigorous AGPAT activity displayed by PlsC316 suggested that plsC316 encodes the main AGPAT required for glycerophospholipid synthesis in R. capsulatus, while olsA acts as an alternative AGPAT that is specific for ornithine lipid synthesis. This study therefore revealed for the first time that some OlsA enzymes, like the enzyme of R. capsulatus, are bifunctional and involved in both membrane ornithine lipid and glycerophospholipid biosynthesis.
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Castellanos M, Kushiro K, Lai SK, Shuler ML. A genomically/chemically complete module for synthesis of lipid membrane in a minimal cell. Biotechnol Bioeng 2007; 97:397-409. [PMID: 17149771 DOI: 10.1002/bit.21251] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A minimal cell is a hypothetical cell defined by the essential functions required for life. We have developed a module for the synthesis of membrane precursors for a mathematical minimal cell model. This module describes, with chemical and genomic detail the production of the constituents required to build a cell membrane and identifies the corresponding essential genes. Membranes allow selective nutrient passage, harmful substance exclusion, and energy generation. Bacterial membrane components range from lipids to fatty acids with embedded proteins and are structurally similar to eukaryotic cell membranes. Membranes are dynamic structures and experimental analyses show great variations in bacterial membrane composition. The flexibility of the model is such that different membrane compositions could be obtained in response to simulated changes in culture conditions. The model's predictions are in close agreement with the observed biological trends. The model's predictions correspond well with the experimental values of total lipid content in cells grown in chemostat culture, but less well with data from batch growth. Cell shape and size results agree especially well for data for growth rate relative to maximum growth rate larger than 0.5; and DNA, RNA, and protein predictions are consistent with experimental observations. A better understanding of the simplest bacterial membrane should lead to insights on the more complex behavior of membranes of higher species as well as identification of potential targets for antimicrobials.
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21
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Rivas M, Seeger M, Jedlicki E, Holmes DS. Second acyl homoserine lactone production system in the extreme acidophile Acidithiobacillus ferrooxidans. Appl Environ Microbiol 2007; 73:3225-31. [PMID: 17351095 PMCID: PMC1907126 DOI: 10.1128/aem.02948-06] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The acidophilic proteobacterium Acidithiobacillus ferrooxidans is involved in the industrial biorecovery of copper. It is found in acidic environments in biofilms and is important in the biogeochemical cycling of metals and nutrients. Its genome contains a cluster of four genes, glyQ, glysS, gph, and act, that are predicted to encode the alpha and beta subunits of glycine tRNA synthetase, a phosphatase, and an acyltransferase, respectively (GenBank accession no. DQ149607). act, cloned and expressed in Escherichia coli, produces acyl homoserine lactones (AHLs) principally of chain length C14 according to gas chromatography and mass spectrometry measurements. The AHLs have biological activity as shown by in vivo studies using the reporter strain Sinorhizobium meliloti Rm41 SinI-. Reverse transcription-PCR (RT-PCR) experiments indicate that the four genes are expressed as a single transcript, demonstrating that they constitute an operon. According to semiquantitative RT-PCR results, act is expressed more highly when A. ferrooxidans is grown in medium containing iron than when it is grown in medium containing sulfur. Since AHLs are important intercellular signaling molecules used by many bacteria to monitor their population density in quorum-sensing control of gene expression, this result suggests that A. ferrooxidans has two quorum-sensing systems, one based on Act, as described herein, and the other based on a Lux-like quorum-sensing system, reported previously. The latter system was shown to be upregulated in A. ferrooxidans grown in sulfur medium, suggesting that the two quorum-sensing systems respond to different environmental signals that may be related to their abilities to colonize and use different solid sulfur- and iron-containing minerals.
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Affiliation(s)
- Mariella Rivas
- Institute of Cellular and Molecular Biology, Faculty of Medicine, University of Chile, Santiago, Chile
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22
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Curtis PD, Geyer R, White DC, Shimkets LJ. Novel lipids in Myxococcus xanthus and their role in chemotaxis. Environ Microbiol 2006; 8:1935-49. [PMID: 17014493 DOI: 10.1111/j.1462-2920.2006.01073.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Organisms that colonize solid surfaces, like Myxococcus xanthus, use novel signalling systems to organize multicellular behaviour. Phosphatidylethanolamine (PE) containing the fatty acid 16:1omega5 (Delta11) elicits a chemotactic response. The phenomenon was examined by observing the effects of PE species with varying fatty acid pairings. Wild-type M. xanthus contains 17 different PE species under vegetative conditions and 19 at the midpoint of development; 13 of the 17 have an unsaturated fatty acid at the sn-1 position, a novelty among Proteobacteria. Myxococcus xanthus has two glycerol-3-phosphate acyltransferase (PlsB) homologues which add the sn-1 fatty acid. Each produces PE with 16:1 at the sn-1 position and supports growth and fruiting body development. Deletion of plsB1 (MXAN3288) results in more dramatic changes in PE species distribution than deletion of plsB2 (MXAN1675). PlsB2 has a putative N-terminal eukaryotic fatty acid reductase domain and may support both ether lipid synthesis and PE synthesis. Disruption of a single sn-2 acyltransferase homologue (PlsC, of which M. xanthus contains five) results in minor changes in membrane PE. Derivatization of purified PE extracts with dimethyldisulfide was used to determine the position of the double bonds in unsaturated fatty acids. The results suggest that Delta5 and Delta11 desaturases may create the double bonds after synthesis of the fatty acid. Phosphatidylethanolamine enriched for 16:1 at the sn-1 position stimulates chemotaxis more strongly than PE with 16:1 enriched at the sn-2 position. It appears that the deployment of a rare fatty acid (16:1omega5) at an unusual position (sn-1) has facilitated the evolution of a novel cell signal.
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Affiliation(s)
- Patrick D Curtis
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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23
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. AKI, . TI, . AY, . KO, . SY, . TK. N-Tetradecanoyl Homoserine Lactone, Signaling Compound for Quorum Sensing, Inhibits Porphyromonas gingivalis Growth. ACTA ACUST UNITED AC 2006. [DOI: 10.3923/jm.2006.353.359] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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24
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Cullinane M, Baysse C, Morrissey JP, O'Gara F. Identification of two lysophosphatidic acid acyltransferase genes with overlapping function in Pseudomonas fluorescens. MICROBIOLOGY-SGM 2005; 151:3071-3080. [PMID: 16151217 DOI: 10.1099/mic.0.27958-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phosphatidic acid (PA) is known to be a crucial phospholipid intermediate in cell membrane biosynthesis. In Escherichia coli, this molecule is produced from lysophosphatidic acid (LPA) by LPA acyltransferase (EC 2.3.1.51), encoded by plsC. E. coli possesses only one such LPA acyltransferase and a plsC mutant is non-permissive for growth at elevated temperatures. This study describes the identification and characterization of two genes from Pseudomonas fluorescens F113 that encode enzymes with LPA acyltransferase activity. One of the genes, hdtS, was previously described, whereas patB is a novel gene. In addition, a putative lyso-ornithine lipid acyltransferase was also identified. All three proteins possess conserved acyltransferase domains and are homologous to PlsC and to LPA acyltransferases identified in Neisseria meningitidis. Functional analysis determined that both HdtS and PatB are functional LPA acyltransferases, as both complemented an E. coli plsC mutant. Mutants lacking each of the putative acyltransferases were constructed and analysed. Growth defects were observed for hdtS and patB single mutants, and a double hdtSpatB mutant could not be constructed. To determine precise roles in phospholipid synthesis, fatty acid methyl ester analysis was carried out. The hdtS mutant displayed a profile consistent with a defect in LPA acyltransferase activity, whereas no such phenotype was observed in the patB mutant, indicating that hdtS encodes the primary LPA acyltransferase in the cell. The presence of at least two genes specifying LPA acyltransferase activity may have implications for the function and survival of P. fluorescens in diverse environments.
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Affiliation(s)
- Méabh Cullinane
- biomerit Research Centre, Microbiology Department and Biosciences Institute, National University of Ireland, Cork, Ireland
| | - Christine Baysse
- biomerit Research Centre, Microbiology Department and Biosciences Institute, National University of Ireland, Cork, Ireland
| | - John P Morrissey
- biomerit Research Centre, Microbiology Department and Biosciences Institute, National University of Ireland, Cork, Ireland
| | - Fergal O'Gara
- biomerit Research Centre, Microbiology Department and Biosciences Institute, National University of Ireland, Cork, Ireland
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25
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Baysse C, Cullinane M, Dénervaud V, Burrowes E, Dow JM, Morrissey JP, Tam L, Trevors JT, O'Gara F. Modulation of quorum sensing in Pseudomonas aeruginosa through alteration of membrane properties. MICROBIOLOGY-SGM 2005; 151:2529-2542. [PMID: 16079332 DOI: 10.1099/mic.0.28185-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Changes in the cellular envelope are major physiological adaptations that occur when micro-organisms encounter extreme environmental conditions. An appropriate degree of membrane fluidity is crucial for survival, and alteration of membrane lipids is an essential adaptive response. Emerging data suggest that microbial cells may recognize alterations in their membrane viscosity resulting from certain environmental changes as a trigger for adaptive cellular responses. In Pseudomonas aeruginosa, the quorum-sensing (QS) system involves a complex regulatory circuitry that coordinates the expression of genes according to a critical population density. Interestingly, it has been shown that the QS system of P. aeruginosa can also be activated by nutritional stress, independently of the cell density, and therefore may be part of a more general adaptive response to stressful environmental conditions. In order to examine the proposed link between membrane properties and stress signalling, the effects of genetically engineered alterations of the membrane phospholipid composition of P. aeruginosa PAO1 on the activation of the stringent response and the QS system were examined. The lptA gene encoding a functional homologue of PlsC, an Escherichia coli enzyme that catalyses the second step of the phospholipid biosynthesis pathway, was identified and disrupted. Inactivation of lptA altered the fatty acid profile of phospholipids and the membrane properties, resulting in decreased membrane fluidity. This resulted in a premature production of the QS signals N-butanoyl- and N-hexanoyl-homoserine lactone (C4-HSL and C6-HSL) and a repression of 2-heptyl-3-hydroxy-4-quinolone (PQS) synthesis at later growth phases. The effects on C4- and C6-HSL depended upon the expression of relA, encoding the (p)ppGpp alarmone synthase, which was increased in the lptA mutant. Together, the findings support the concept that alterations in membrane properties can act as a trigger for stress-related gene expression.
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Affiliation(s)
- Christine Baysse
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
| | - Méabh Cullinane
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
| | - Valérie Dénervaud
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
| | - Elizabeth Burrowes
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
| | - J Maxwell Dow
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
| | - John P Morrissey
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
| | - Ling Tam
- Department of Environmental Biology, Rm 3220 Bovey Building, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Jack T Trevors
- Department of Environmental Biology, Rm 3220 Bovey Building, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Fergal O'Gara
- BIOMERIT Research Centre, Microbiology Department, University College Cork, National University of Ireland, Cork, Ireland
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Kahler CM, Datta A, Tzeng YL, Carlson RW, Stephens DS. Inner core assembly and structure of the lipooligosaccharide of Neisseria meningitidis: capacity of strain NMB to express all known immunotype epitopes. Glycobiology 2004; 15:409-19. [PMID: 15574803 DOI: 10.1093/glycob/cwi018] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neisseria meningitidis expresses a heterogeneous population of lipooligosaccharide (LOS) inner cores variously substituted with alpha1-3-linked glucose and O-3, O-6, and O-7 linked phosphoethanolamine (PEA), as well as glycine, attached to HepII. Combinations of these attachments to the LOS inner core represent immunodominant epitopes that are being exploited as future vaccine candidates. Historically, each LOS immunotype was structurally assessed and prescribed a certain unique inner core epitope. We report that a single isolate, strain NMB, possesses the capacity to produce all of the known neisserial LOS inner core immunotype structures. Analysis of the inner cores from parental LOS revealed the presence or absence of alpha1,3-linked glucose, O-6 and/or O-7 linked PEA, in addition to glycine attached at the 7 position of the HepII inner core. Identification and inactivation of lpt-6 in strain NMB resulted in the loss of both O-6 and O-7 linked PEA groups from the LOS inner core, suggesting that Lpt-6 of strain NMB may have bifunctional transferase activities or that the O-6 linked PEA groups once attached to the inner core undergo nonenzymatic transfer to the O-7 position of HepII. Although O-3 linked PEA was not detected in parental LOS inner cores devoid of alpha1-3-linked glucose residues, LOS glycoforms bearing O-3 PEA groups accumulated in a truncated mutant, NMBlgtK (Hep2Kdo2-lipid A). Because these structures disappeared upon inactivation of the lpt-3 locus, strain NMB expresses a functional O-3 PEA transferase. The LOS glycoforms expressed by NMBlgtK were also devoid of glycine attachments, indicating that glycine was added to the inner core after the completion of the gamma-chain by LgtK. In conclusion, strain NMB has the capability to express all known inner core structures, but in in vitro culture L2 and L4 immunotype structures are predominantly expressed.
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Affiliation(s)
- Charlene M Kahler
- Department of Microbiology, Monash University, Clayton 3800, Australia.
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Thomas EA, George RC, Danielson PE, Nelson PA, Warren AJ, Lo D, Sutcliffe JG. Antipsychotic drug treatment alters expression of mRNAs encoding lipid metabolism-related proteins. Mol Psychiatry 2003; 8:983-93, 950. [PMID: 14647396 DOI: 10.1038/sj.mp.4001425] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Using an automated PCR-based genomics approach, TOtal Gene expression Analysis (TOGA), we have examined gene expression profiles of mouse striatum and frontal cortex in response to clozapine and haloperidol drug treatment. Of 17 315 mRNAs observed, TOGA identified several groups of related molecules that were regulated by drug treatment. The expression of some genes encoding proteins involved in neurotransmission, signal transduction, oxidative stress, cell adhesion, apoptosis and proteolysis were altered in the brains of both clozapine- and haloperidol-treated mice as recognized by TOGA. Most notable was the differential expression of those genes whose products are associated with lipid metabolism. These include apolipoprotein D (apoD), the mouse homolog of oxysterol-binding protein-like protein 8 (OSBPL8), a diacylglycerol receptor (n-chimerin), and lysophosphatidic acid (LPA) acyltransferase. Real-time PCR analysis confirmed increases in the RNA expression of apoD (1.6-2.2-fold) and OSBPL8 (1.7-2.6-fold), and decreases in the RNA expression of n-chimerin (1.5-2.2-fold) and LPA acyltransferase (1.5-fold) in response to haloperidol and/or clozapine treatment. Additional molecules related to calcium homeostasis and signal transduction, as well as four sequences of previously unidentified mRNAs, were also confirmed by real-time PCR to be regulated by drug treatment. While antipsychotic drugs may affect several metabolic pathways, lipid metabolism/signaling pathways may be of particular importance in the mechanisms of antipsychotic drug action and in the pathophysiology of psychiatric disorders.
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Affiliation(s)
- E A Thomas
- 1Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
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Weissenmayer B, Gao JL, López-Lara IM, Geiger O. Identification of a gene required for the biosynthesis of ornithine-derived lipids. Mol Microbiol 2002; 45:721-33. [PMID: 12139618 DOI: 10.1046/j.1365-2958.2002.03043.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Phospholipids are the membrane-forming constituents in all living organisms. In addition to phosphorus-containing lipids, the membranes of numerous bacteria contain significant amounts of phosphorus-free polar lipids, often derived from amino acids. Although lipids derived from the amino acid ornithine are widespread among bacteria, their biosynthesis is unknown. Here, we describe the isolation of mutants of Sinorhizobium meliloti deficient in the biosynthesis of ornithine-derived lipids (OL). Complementation of such mutants with a sinorhi-zobial cosmid gene bank, subcloning of the complementing fragment and sequencing of the subclone led to the identification of a gene (olsA) coding for a presumptive acyltransferase. Amplification of this gene and its expression in OL-deficient mutant backgrounds of S. meliloti demonstrates that it is required for OL biosynthesis. An OL-deficient mutant of S. meliloti disrupted in olsA shows wild type-like growth behaviour and is capable of inducing nitrogen-fixing nodules on legume hosts. A lyso-ornithine lipid-dependent acyltransferase activity forming OL requires acyl-AcpP as the acyl donor and expression of the olsA gene.
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Affiliation(s)
- Barbara Weissenmayer
- Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos
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Steeghs L, Cock HD, Evers E, Zomer B, Tommassen J, Ley PVD. Outer membrane composition of a lipopolysaccharide-deficient Neisseria meningitidis mutant. EMBO J 2001; 20:6937-45. [PMID: 11742971 PMCID: PMC125796 DOI: 10.1093/emboj/20.24.6937] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2001] [Revised: 10/22/2001] [Accepted: 11/01/2001] [Indexed: 11/13/2022] Open
Abstract
In the pathogen Neisseria meningitidis, a completely lipopolysaccharide (LPS)-deficient but viable mutant can be obtained by insertional inactivation of the lpxA gene, encoding UDP-GlcNAc acyltransferase required for the first step of lipid A biosynthesis. To study how outer membrane structure and biogenesis are affected by the absence of this normally major component, inner and outer membranes were separated and their composition analysed. The expression and assembly of integral outer membrane proteins appeared largely unaffected. However, the expression of iron limitation-inducible, cell surface-exposed lipoproteins was greatly reduced. Major changes were seen in the phospholipid composition, with a shift towards phosphatidylethanolamine and phosphatidylglycerol species containing mostly shorter chain, saturated fatty acids, one of which was unique to the LPS-deficient outer membrane. The presence of the capsular polysaccharide turned out to be essential for viability without LPS, as demonstrated by using a strain in which LPS biosynthesis could be switched on or off through a tac promoter-controlled lpxA gene. Taken together, these results can help to explain why meningococci have the unique ability to survive without LPS.
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Affiliation(s)
- Liana Steeghs
- Laboratory of Vaccine Research and Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven and Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands Corresponding author at: Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands e-mail:
| | - Hans de Cock
- Laboratory of Vaccine Research and Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven and Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands Corresponding author at: Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands e-mail:
| | - Evert Evers
- Laboratory of Vaccine Research and Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven and Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands Corresponding author at: Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands e-mail:
| | - Bert Zomer
- Laboratory of Vaccine Research and Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven and Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands Corresponding author at: Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands e-mail:
| | - Jan Tommassen
- Laboratory of Vaccine Research and Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven and Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands Corresponding author at: Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands e-mail:
| | - Peter van der Ley
- Laboratory of Vaccine Research and Laboratory of Organic-Analytical Chemistry, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven and Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands Corresponding author at: Laboratory of Vaccine Research, National Institute of Public Health and the Environment, RIVM, Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands e-mail:
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Shih GC, Kahler CM, Carlson RW, Rahman MM, Stephens DS. gmhX, a novel gene required for the incorporation of L-glycero-D-manno-heptose into lipooligosaccharide in Neisseria meningitidis. MICROBIOLOGY (READING, ENGLAND) 2001; 147:2367-2377. [PMID: 11496013 DOI: 10.1099/00221287-147-8-2367] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Lipooligosaccharide (LOS) is a critical virulence factor of Neisseria meningitidis. A Tn916 insertion mutant, designated 469, was found to exhibit a markedly truncated LOS of 2.9 kDa when compared by Tricine/SDS-PAGE to the parental LOS (4.6 kDa). Electrospray mass spectrometry analysis of 469 LOS revealed that it consisted of the deep rough, heptose-deficient structure, Kdo(2)-lipid A. Sequencing of chromosomal DNA flanking the Tn916 insertion in mutant 469 revealed that the transposon had inserted into an ORF predicted to encode a 187 aa protein with sequence homology to the histidinol-phosphate phosphatase domain of Escherichia coli HisB and to a family of genes of unknown function. The gene, designated gmhX, is part of a polycistronic operon (ice-2) containing two other genes, nlaB and orfC. nlaB encodes a lysophosphatidic-acid acyltransferase and orfC is predicted to encode a N-acetyltransferase. Specific polar and non-polar gmhX mutations in the parental strain, NMB, exhibited the truncated LOS structure of mutant 469, and repair of gmhX mutants by homologous recombination with the wild-type gmhX restored the LOS parental phenotype. GmhX mutants demonstrated increased sensitivity to polymyxin B. GmhX mutants and other Kdo(2)-lipid A mutants also demonstrated increased sensitivity to killing by normal human serum but were not as sensitive as inner-core mutants containing heptose. In the genomes of Helicobacter pylori and Synechocystis, gmhX homologues are associated with heptose biosynthesis genes; however, in N. meningitidis, gmhX was found in a location distinct from that of gmhA, rfaD, rfaE, aut and rfaC. GmhX is a novel enzyme required for the incorporation of L-glycero-D-manno-heptose into meningococcal LOS, and is a candidate for the 2-D-glycero-manno-heptose phosphatase of the heptose biosynthesis pathway.
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Affiliation(s)
- Giles C Shih
- Department of Veterans Affairs Medical Center, Atlanta, GA 30033, USA2
- Departments of Medicine, and Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA1
| | - Charlene M Kahler
- Department of Veterans Affairs Medical Center, Atlanta, GA 30033, USA2
- Departments of Medicine, and Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA1
| | - Russell W Carlson
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA3
| | - M Mahbubur Rahman
- The Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA3
| | - David S Stephens
- Department of Veterans Affairs Medical Center, Atlanta, GA 30033, USA2
- Departments of Medicine, and Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA1
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Laue BE, Jiang Y, Chhabra SR, Jacob S, Stewart GSAB, Hardman A, Downie JA, O'Gara F, Williams P. The biocontrol strain Pseudomonas fluorescens F113 produces the Rhizobium small bacteriocin, N-(3-hydroxy-7-cis-tetradecenoyl)homoserine lactone, via HdtS, a putative novel N-acylhomoserine lactone synthase. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 10):2469-2480. [PMID: 11021923 DOI: 10.1099/00221287-146-10-2469] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several different species of Pseudomonas: produce N:-acylhomoserine lactones (AHLs), quorum-sensing signal molecules which are involved in the cell-density-dependent control of secondary metabolite and virulence gene expression. When Pseudomonas fluorescens F113 was cross-streaked against AHL biosensors capable of sensitively detecting either short (C(4)-C(8)) or long (C(10)-C(14)) acyl chain AHLs, no activity was detectable. However, by extracting cell-free stationary-phase culture supernatants with dichloromethane followed by reverse-phase HPLC, three distinct fractions were obtained capable of activating the AHL biosensors. Three AHLs were subsequently characterized using high-resolution MS and chemical synthesis. These were (i) N:-(3-hydroxy-7-cis-tetradecenoyl)homoserine lactone (3OH, C(14:1)-HSL), a molecule previously known as the Rhizobium leguminosarum small bacteriocin as a consequence of its growth inhibitory properties, (ii) N:-decanoylhomoserine lactone (C(10)-HSL) and (iii) N:-hexanoylhomoserine lactone (C(6)-HSL). A gene (hdtS) capable of directing synthesis of all three P. fluorescens AHLs in Escherichia coli was cloned and sequenced. In vitro transcription/translation of hdtS yielded a protein of approximately 33 kDa capable of directing the synthesis of 3OH, C(14:1)-HSL, C(10)-HSL and C(6)-HSL in E. coli. HdtS does not belong to either of the known AHL synthase families (LuxI or LuxM) and is related to the lysophosphatidic acid acyltransferase family. HdtS may therefore constitute a member of a third protein family capable of AHL biosynthesis.
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Affiliation(s)
- Bridget E Laue
- School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1
| | - Yan Jiang
- School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1
| | - Siri Ram Chhabra
- School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1
| | - Sinead Jacob
- Biomerit Research Centre, Department of Microbiology, National University of Ireland, Cork, Ireland2
| | - Gordon S A B Stewart
- School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1
| | - Andrea Hardman
- School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1
| | | | - Fergal O'Gara
- Biomerit Research Centre, Department of Microbiology, National University of Ireland, Cork, Ireland2
| | - Paul Williams
- School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1
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Rahman MM, Kolli VSK, Kahler CM, Shih G, Stephens DS, Carlson RW. The membrane phospholipids of Neisseria meningitidis and Neisseria gonorrhoeae as characterized by fast atom bombardment mass spectrometry. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 8):1901-1911. [PMID: 10931894 DOI: 10.1099/00221287-146-8-1901] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The phospholipids of Neisseria meningitidis and Neisseria gonorrhoeae were characterized by fast atom bombardment (FAB)-MS and GLC-MS. The major phospholipids were phosphatidylethanolamine (PE), followed by phosphatidylglycerol (PG), with minor amounts of phosphatidic acid (PA) and trace levels of cardiolipin (DPG). All of the phospholipid preparations were variable in their fatty acyl substituents, which included C16:1, C16:0, C18:1, C14:0, C14:1 and C12:0. By MS/MS analysis, all pathogenic Neisseria spp. phospholipids contained a saturated fatty acyl substituent and either a saturated or unsaturated fatty acyl substituent in the sn-1 and sn-2 positions, respectively. Compared with enteric bacterial species, the phospholipids of N. meningitidis and N. gonorrhoeae have increased levels of phospholipids with short-chain fatty acyl residues (i.e. increases in C12:0, C14:1 and C14:0) and variable amounts of C18:1. The percentage of total PE and PG molecules with the shorter-chain fatty acids ranges from 35 to 47% and 42 to 66%, respectively, for N. meningitidis while these respective values are <10% and <5% for Escherichia coli. The variability and variety of meningococcal and gonococcal phospholipids suggest novel genetic mechanisms of neisserial phospholipid assembly and regulation, which may be important for the biology and pathogenesis of N. meningitidis and N. gonorrhoeae.
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Affiliation(s)
- M Mahbubur Rahman
- Complex Carbohydrate Research Center, The University of Georgia, 220 Riverbend Road, Athens, GA 30602, USA1
| | - V S Kumar Kolli
- Complex Carbohydrate Research Center, The University of Georgia, 220 Riverbend Road, Athens, GA 30602, USA1
| | - Charlene M Kahler
- Departments of Medicine and Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30303, and Department of Veterans Affairs Medical Center, Atlanta, GA, USA2
| | - Giles Shih
- Departments of Medicine and Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30303, and Department of Veterans Affairs Medical Center, Atlanta, GA, USA2
| | - David S Stephens
- Departments of Medicine and Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30303, and Department of Veterans Affairs Medical Center, Atlanta, GA, USA2
| | - Russell W Carlson
- Complex Carbohydrate Research Center, The University of Georgia, 220 Riverbend Road, Athens, GA 30602, USA1
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Kahler CM, Martin LE, Shih GC, Rahman MM, Carlson RW, Stephens DS. The (alpha2-->8)-linked polysialic acid capsule and lipooligosaccharide structure both contribute to the ability of serogroup B Neisseria meningitidis to resist the bactericidal activity of normal human serum. Infect Immun 1998; 66:5939-47. [PMID: 9826376 PMCID: PMC108752 DOI: 10.1128/iai.66.12.5939-5947.1998] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The molecular basis for the resistance of serogroup B Neisseria meningitidis to the bactericidal activity of normal human sera (NHS) was examined with a NHS-resistant, invasive serogroup B meningococcal isolate and genetically and structurally defined capsule-, lipooligosaccharide (LOS)-, and sialylation-altered mutants of the wild-type strain. Expression of the (alpha2-->8)-linked polysialic acid serogroup B capsule was essential for meningococcal resistance to NHS. The very NHS-sensitive phenotype of acapsular mutants (99.9 to 100% killed in 10, 25, and 50% NHS) was not rescued by complete LOS sialylation or changes in LOS structure. However, expression of the capsule was necessary but not sufficient for a fully NHS-resistant phenotype. In an encapsulated background, loss of LOS sialylation by interrupting the alpha2,3 sialyltransferase gene, lst, increased sensitivity to 50% NHS. In contrast, replacement of the lacto-N-neotetraose alpha-chain (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) with glucose extensions (GlcN) in a galE mutant resulted in a strain resistant to killing by 50% NHS at all time points. Encapsulated meningococci expressing a Hep2(GlcNAc)-->KDO2-->lipid A LOS without an alpha-chain demonstrated enhanced sensitivity to 50% NHS (98% killed at 30 min) mediated through the antibody-dependent classical complement pathway. Encapsulated LOS mutants expressing truncated Hep2-->KDO2-->lipid A and KDO2-->lipid A structures were also sensitive to 50% NHS (98 to 100% killed at 30 min) but, unlike the wild-type strain and mutants with larger oligosaccharide structures, they were killed by hypogammaglobulinemic sera. These data indicate that encapsulation is essential but that the LOS structure contributes to the ability of serogroup B N. meningitidis to resist the bactericidal activity of NHS.
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Affiliation(s)
- C M Kahler
- Departments of Medicine, and VA Medical Center, Atlanta, Georgia 30033, USA
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