The Experts below are selected from a list of 17067 Experts worldwide ranked by ideXlab platform
Philippe Jacques - One of the best experts on this subject based on the ideXlab platform.
-
Antifungal Activities of Bacillus subtilis Lipopeptides to Two Venturia inaequalis Strains Possessing Different Tebuconazole Sensitivity
Frontiers in Microbiology, 2019Co-Authors: Hélène Desmyttere, François Coutte, Caroline Deweer, Jérôme Muchembled, Karin Sahmer, Justine Jacquin, Philippe JacquesAbstract:Within the framework of biocontrol development, three natural substances produced by Bacillus subtilis, called Lipopeptides, have been studied: fengycin (F), surfactin (S) and mycosubtilin (M). Their antifungal properties were tested in vitro, in liquid medium, on two strains of Venturia inaequalis, ascomycete fungi causing apple scab. These two strains were respectively sensitive and less sensitive to tebuconazole, an active substance of the triazole family. These three molecules were tested on their own, in binary (FS, FM, SM) and ternary mixtures (FSM). The antifungal activities of Lipopeptides were estimated by calculating an IC50, compared to tebuconazole chemical substance. In tests involving the sensitive strain, all lipopeptide modalities exhibited antifungal activity. However, modalities involving fengycin and its mixtures exhibited the best antifungal activities; the activity of fengycin alone being very similar to that of tebuconazole. Interestingly, regarding the strain with reduced sensitivity to tebuconazole, surfactin and fengycin alone were not efficient while mycosubtilin and the different mixtures showed interesting antifungal activities. Specifically, the antifungal activity of FS and FSM mixture were equivalent to that of tebuconazole. For both fungal strains, microscopic observations revealed important morphological modifications in the presence of fengycin and in a less important proportion in the presence of surfactin but not in the presence of mycosubtilin. Overall, this study highlights the diversity in mode of action of Lipopeptides on apple scab strains.
-
Lipopeptide biodiversity in antifungal Bacillus strains isolated from Algeria
Archives of Microbiology, 2018Co-Authors: Lamia Abdellaziz, Gabrielle Chataigné, Marlène Chollet, Ahmed Abderrahmani, Lamia Yaici, Anthony Arguelles Arias, Max Béchet, Valérie Leclère, Philippe JacquesAbstract:Several Bacillus strains have been well studied for their ability to control soil-borne plant diseases. This property is linked to the production of several families of Lipopeptides. Depending of their structure, these compounds show antifungal and/or plant systemic resistance inducing activities. In this work, the biodiversity of Lipopeptides produced by different antifungal Bacillus strains isolated from seeds, rhizospheric, and non-rhizospheric soils in Algeria was analyzed. Sixteen active strains were characterized by PCR for their content in genes involved in lipopeptide biosynthesis and by MALDI-ToF for their lipopeptide production, revealing a high biodiversity of products. The difficulty to detect kurstakin genes led us to design two new sets of specific primers. An interesting potential of antifungal activity and the synthesis of two forms of fengycins differing in the eighth amino acid (Gln/Glu) were found from the strain 8. Investigation of its genome led to the finding of an adenylation domain of the fengycin synthetase predicted to activate the glutamate residue instead of the glutamine one. According to the comparison of both the results of MALDI-ToF-MS and genome analysis, it was concluded that this adenylation domain could activate both residues at the same time. This study highlighted that the richness of the Algerian ecosystems in Bacillus strains is able to produce: surfactin, pumilacidin, lichenysin, kurstakin, and different types of fengycins.
-
Bioinformatics tools for the discovery of new Lipopeptides with biocontrol applications
European Journal of Plant Pathology, 2018Co-Authors: Maude Pupin, Areski Flissi, Philippe Jacques, Valérie LeclèreAbstract:As conventional or chemical pesticides have negative impact on environment and health of both farmer and consumers, it becomes relevant to develop alternative solutions to limit their use. In this context, innovative strategies to accelerate the development of biocontrol agents are welcome. For a decade of years, it has been demonstrated that Lipopeptides are very efficient weapons against fungi responsible for crop diseases. Lipopeptides are secondary metabolites, produced by many microorganisms including beneficial rhizobacteria. The lipopeptide biosynthetic pathways include nonribosomal peptide synthetases. These modular enzymatic complexes work as assembly lines to build the peptides step by step, leading to the production of original peptide compounds with specific features as the presence of non proteinogenic monomers and cyclic and branched structures. In this paper, Florine and Norine bioinformatics tools, especially dedicated to non-ribosomal synthetases and their products are presented. Their use is mainly focused on the discovery of Lipopeptides produced by Bacillus or Pseudomonas because they seem to represent a versatile reservoir of active secondary metabolites with promising activities for applications in phytosanitary area.
-
Burkholderia genome mining for nonribosomal peptide synthetases reveals a great potential for novel siderophores and Lipopeptides synthesis
MicrobiologyOpen, 2016Co-Authors: Qassim Esmaeel, Gabrielle Chataigné, Maude Pupin, Nam Phuong Kieu, Jovana Deravel, Fabrice Krier, Monica Hofte, Max Béchet, Philippe Jacques, Valérie LeclèreAbstract:Burkholderia is an important genus encompassing a variety of species, including pathogenic strains as well as strains that promote plant growth. We have carried out a global strategy, which combined two complementary approaches. The first one is genome guided with deep analysis of genome sequences and the second one is assay guided with experiments to support the predictions obtained in silico. This efficient screening for new secondary metabolites, performed on 48 gapless genomes of Burkholderia species, revealed a total of 161 clusters containing nonribosomal peptide synthetases (NRPSs), with the potential to synthesize at least 11 novel products. Most of them are siderophores or Lipopeptides, two classes of products with potential application in biocontrol. The strategy led to the identification, for the first time, of the cluster for cepaciachelin biosynthesis in the genome of Burkholderia ambifaria AMMD and a cluster corresponding to a new malleobactin-like siderophore, called phymabactin, was identified in Burkholderia phymatum STM815 genome. In both cases, the siderophore was produced when the strain was grown in iron-limited conditions. Elsewhere, the cluster for the antifungal burkholdin was detected in the genome of B. ambifaria AMMD and also Burkholderia sp. KJ006. Burkholderia pseudomallei strains harbor the genetic potential to produce a novel lipopeptide called burkhomycin, containing a peptidyl moiety of 12 monomers. A mixture of Lipopeptides produced by Burkholderia rhizoxinica lowered the surface tension of the supernatant from 70 to 27 mN·m−1. The production of nonribosomal secondary metabolites seems related to the three phylogenetic groups obtained from 16S rRNA sequences. Moreover, the genome-mining approach gave new insights into the nonribosomal synthesis exemplified by the identification of dual C/E domains in lipopeptide NRPSs, up to now essentially found in Pseudomonas strains.
-
burkholderia genome mining for nonribosomal peptide synthetases reveals a great potential for novel siderophores and Lipopeptides synthesis
arXiv: Quantitative Methods, 2016Co-Authors: Qassim Esmaeel, Gabrielle Chataigné, Marion Bechet, Maude Pupin, Nam Phuong Kieu, Jovana Deravel, Fabrice Krier, Monica Hofte, Philippe JacquesAbstract:Burkholderia is an important genus encompassing a variety of species, including pathogenic strains as well as strains that promote plant growth. We have carried out a global strategy, which combined two complementary approaches. The first one is genome guided with deep analysis of genome sequences and the second one is assay guided with experiments to support the predictions obtained in silico. This efficient screening for new secondary metabolites, performed on 48 gapless genomes of Burkholderia species, revealed a total of 161 clusters containing nonribosomal peptide synthetases (NRPSs), with the potential to synthesize at least 11 novel products. Most of them are siderophores or Lipopeptides, two classes of products with potential application in biocontrol. The strategy led to the identification, for the first time, of the cluster for cepaciachelin biosynthesis in the genome of Burkholderia ambifaria AMMD and a cluster corresponding to a new malleobactin-like siderophore, called phymabactin, was identified in Burkholderia phymatum STM815 genome. In both cases, the siderophore was produced when the strain was grown in iron-limited conditions. Elsewhere, the cluster for the antifungal burkholdin was detected in the genome of B. ambifaria AMMD and also Burkholderia sp. KJ006. Burkholderia pseudomallei strains harbor the genetic potential to produce a novel lipopeptide called burkhomycin, containing a peptidyl moiety of 12 monomers. A mixture of Lipopeptides produced by Burkholderia rhizoxinica lowered the surface tension of the supernatant from 70 to 27 mN·m−1. The production of nonribosomal secondary metabolites seems related to the three phylogenetic groups obtained from 16S rRNA sequences. Moreover, the genome-mining approach gave new insights into the nonribosomal synthesis exemplified by the identification of dual C/E domains in lipopeptide NRPSs, up to now essentially found in Pseudomonas strains.
Artur J. Ulmer - One of the best experts on this subject based on the ideXlab platform.
-
Identification of full length bovine TLR1 and functional characterization of lipopeptide recognition by bovine TLR2/1 heterodimer
Veterinary Research, 2010Co-Authors: Katja Farhat, Günther Jung, Karl-heinz Wiesmüller, Sabine Riekenberg, Thomas W. Jungi, Artur J. UlmerAbstract:Toll-like receptors (TLR) are highly conserved pattern recognition receptors of the innate immune system. Toll-like receptor 2 (TLR2) recognizes bacterial Lipopeptides in a heterodimeric complex with TLR6 or TLR1, thereby discriminating between di- or triacylated Lipopeptides, respectively. Previously, we found that HEK293 cells transfected with bovine TLR2 (boTLR2) were able to respond to diacylated Lipopeptides but did not recognize triacylated Lipopeptides, even after cotransfection with the so far published sequence of boTLR1. In this study we now could show that primary bovine cells were in general able to detect triacylated lipopetides. A closer investigation of the boTLR1 gene locus revealed an additional ATG 195 base pairs upstream from the published start codon. Its transcription would result in an N-terminus with high identity to human and murine TLR1 (huTLR1, muTLR1). Cloning and cotransfection of this longer boTLR1 with boTLR2 now resulted in the recognition of triacylated Lipopeptides by HEK293 cells, thereby resembling the ex vivo observation. Analysis of the structure-activity relationship showed that the ester-bound acid chains of these Lipopeptides need to consist of at least 12 carbon atoms to activate the bovine heterodimer showing similarity to the recognition by huTLR2/huTLR1. In contrast, HEK293 cell cotransfected with muTLR2 and muTLR1 could already be activated by Lipopeptides with shorter fatty acids of only 6 carbon atoms. Thus, our data indicate that the additional N-terminal nucleotides belong to the full length and functionally active boTLR1 (boTLR1-fl) which participates in a species-specific recognition of bacterial Lipopeptides.
-
TLR1- and TLR6-independent recognition of bacterial Lipopeptides.
Journal of Biological Chemistry, 2006Co-Authors: Ute Buwitt-beckmann, Holger Heine, Günther Jung, Roland Brock, Karl-heinz Wiesmüller, Artur J. UlmerAbstract:Bacterial cell walls contain lipoproteins/peptides, which are strong modulators of the innate immune system. Triacylated Lipopeptides are assumed to be recognized by TLR2/TLR1-, whereas diacylated Lipopeptides use TLR2/TLR6 heteromers for signaling. Following our initial discovery of TLR6-independent diacylated Lipopeptides, we could now characterize di- and triacylated Lipopeptides (e.g. Pam(2)C-SK(4), Pam(3)C-GNNDESNISFKEK), which have stimulatory activity in TLR1- and in TLR6-deficient mice. Furthermore, for the first time, we present triacylated Lipopeptides with short length ester-bound fatty acids (like PamOct(2)C-SSNASK(4)), which induce no response in TLR1-deficient cells. No differences in the phosphorylation of MAP kinases by lipopeptide analogs having different TLR2-coreceptor usage were observed. Blocking experiments indicated that different TLR2 heteromers recognize their specific lipopeptide ligands independently from each other. In summary, a triacylation pattern is necessary but not sufficient to render a lipopeptide TLR1-dependent, and a diacylation pattern is necessary but not sufficient to render a lipopeptide TLR6-dependent. Contrary to the current model, distinct Lipopeptides are recognized by TLR2 in a TLR1- and TLR6-independent manner.
-
Toll-like receptor 6-independent signaling by diacylated Lipopeptides.
European Journal of Immunology, 2004Co-Authors: Ute Buwitt-beckmann, Holger Heine, Günther Jung, Roland Brock, Karl-heinz Wiesmüller, Artur J. UlmerAbstract:Bacterial Lipopeptides are strong immune modulators that activate early host responses after infection as well as initiating adjuvant effects on the adaptive immune system. These Lipopeptides induce signaling in cells of the immune system through Toll-like receptor 2 (TLR2)–TLR1 or TLR2–TLR6 heteromers. So far it has been thought that triacylated Lipopeptides, such as the synthetic N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam3)-CSK4, signal through TLR2–TLR1 heteromers, whereas diacylated Lipopeptides, like the macrophage-activating lipopeptide from Mycoplasma fermentans (MALP2) or S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam2)-CGNNDESNISFKEK, induce signaling through TLR2–TLR6 heteromers. Using new synthetic lipopeptide derivatives we addressed the contribution of the lipid and, in particular, the peptide moieties with respect to TLR2 heteromer usage. In contrast to the current model of receptor usage, not only triacylated Lipopeptides, but also diacylated Lipopeptides like Pam2CSK4 and the elongated MALP2 analog Pam2CGNNDESNISFKEK-SK4 (MALP2-SK4) induced B lymphocyte proliferation and TNF-α secretion in macrophages in a TLR6-independent manner as determined with cells from TLR6-deficient mice. Our results indicate that both the lipid and the N-terminal peptides of lipoproteins contribute to the specificity of recognition by TLR2 heteromers and are responsible for the ligand–receptor interaction on host cells.
Günther Jung - One of the best experts on this subject based on the ideXlab platform.
-
Identification of full length bovine TLR1 and functional characterization of lipopeptide recognition by bovine TLR2/1 heterodimer
Veterinary Research, 2010Co-Authors: Katja Farhat, Günther Jung, Karl-heinz Wiesmüller, Sabine Riekenberg, Thomas W. Jungi, Artur J. UlmerAbstract:Toll-like receptors (TLR) are highly conserved pattern recognition receptors of the innate immune system. Toll-like receptor 2 (TLR2) recognizes bacterial Lipopeptides in a heterodimeric complex with TLR6 or TLR1, thereby discriminating between di- or triacylated Lipopeptides, respectively. Previously, we found that HEK293 cells transfected with bovine TLR2 (boTLR2) were able to respond to diacylated Lipopeptides but did not recognize triacylated Lipopeptides, even after cotransfection with the so far published sequence of boTLR1. In this study we now could show that primary bovine cells were in general able to detect triacylated lipopetides. A closer investigation of the boTLR1 gene locus revealed an additional ATG 195 base pairs upstream from the published start codon. Its transcription would result in an N-terminus with high identity to human and murine TLR1 (huTLR1, muTLR1). Cloning and cotransfection of this longer boTLR1 with boTLR2 now resulted in the recognition of triacylated Lipopeptides by HEK293 cells, thereby resembling the ex vivo observation. Analysis of the structure-activity relationship showed that the ester-bound acid chains of these Lipopeptides need to consist of at least 12 carbon atoms to activate the bovine heterodimer showing similarity to the recognition by huTLR2/huTLR1. In contrast, HEK293 cell cotransfected with muTLR2 and muTLR1 could already be activated by Lipopeptides with shorter fatty acids of only 6 carbon atoms. Thus, our data indicate that the additional N-terminal nucleotides belong to the full length and functionally active boTLR1 (boTLR1-fl) which participates in a species-specific recognition of bacterial Lipopeptides.
-
TLR1- and TLR6-independent recognition of bacterial Lipopeptides.
Journal of Biological Chemistry, 2006Co-Authors: Ute Buwitt-beckmann, Holger Heine, Günther Jung, Roland Brock, Karl-heinz Wiesmüller, Artur J. UlmerAbstract:Bacterial cell walls contain lipoproteins/peptides, which are strong modulators of the innate immune system. Triacylated Lipopeptides are assumed to be recognized by TLR2/TLR1-, whereas diacylated Lipopeptides use TLR2/TLR6 heteromers for signaling. Following our initial discovery of TLR6-independent diacylated Lipopeptides, we could now characterize di- and triacylated Lipopeptides (e.g. Pam(2)C-SK(4), Pam(3)C-GNNDESNISFKEK), which have stimulatory activity in TLR1- and in TLR6-deficient mice. Furthermore, for the first time, we present triacylated Lipopeptides with short length ester-bound fatty acids (like PamOct(2)C-SSNASK(4)), which induce no response in TLR1-deficient cells. No differences in the phosphorylation of MAP kinases by lipopeptide analogs having different TLR2-coreceptor usage were observed. Blocking experiments indicated that different TLR2 heteromers recognize their specific lipopeptide ligands independently from each other. In summary, a triacylation pattern is necessary but not sufficient to render a lipopeptide TLR1-dependent, and a diacylation pattern is necessary but not sufficient to render a lipopeptide TLR6-dependent. Contrary to the current model, distinct Lipopeptides are recognized by TLR2 in a TLR1- and TLR6-independent manner.
-
Synthetic Lipopeptides as novel adjuvants.
Research in Immunology, 2004Co-Authors: Wolfgang G. Bessler, Günther JungAbstract:Summary Lipopeptides constitute potent novel immunoadjuvants in mice, rabbits and other species, enhancing markedly the immune response when given in mixture with antigens. Lipopeptides are non-toxic, non-pyrogenic and do not induce tissue damage when injected. They are thus well suited to replace Freund's adjuvant avoiding its side effects ; the antibody titres obtained using lipopeptide analogues are in most cases comparable to the titres obtained by administering Freund's adjuvant. Lipopeptides also improve the efficiency of vaccines, which is important in decreasing the amount of vaccine required. Lipopeptides covalently coupled to low molecular weight haptens, e.g. peptides or toxins, are able to elicit high antigenspecific antibody titres in mice and rabbits. Conjugates containing B or T helper cell epitopes constitute novel synthetic vaccines which protect against viral infections by inducing virus-specific antibodies. When coupled to CTL epitopes, the conjugates are able to induce cytotoxic T lymphocytes in vivo which eliminate virus-infected cells. Thus, due to their efficacy and their lack of side effects, these novel lipopeptide adjuvants provide a substitute for many conventional adjuvants.
-
Toll-like receptor 6-independent signaling by diacylated Lipopeptides.
European Journal of Immunology, 2004Co-Authors: Ute Buwitt-beckmann, Holger Heine, Günther Jung, Roland Brock, Karl-heinz Wiesmüller, Artur J. UlmerAbstract:Bacterial Lipopeptides are strong immune modulators that activate early host responses after infection as well as initiating adjuvant effects on the adaptive immune system. These Lipopeptides induce signaling in cells of the immune system through Toll-like receptor 2 (TLR2)–TLR1 or TLR2–TLR6 heteromers. So far it has been thought that triacylated Lipopeptides, such as the synthetic N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam3)-CSK4, signal through TLR2–TLR1 heteromers, whereas diacylated Lipopeptides, like the macrophage-activating lipopeptide from Mycoplasma fermentans (MALP2) or S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-(R)-cysteine (Pam2)-CGNNDESNISFKEK, induce signaling through TLR2–TLR6 heteromers. Using new synthetic lipopeptide derivatives we addressed the contribution of the lipid and, in particular, the peptide moieties with respect to TLR2 heteromer usage. In contrast to the current model of receptor usage, not only triacylated Lipopeptides, but also diacylated Lipopeptides like Pam2CSK4 and the elongated MALP2 analog Pam2CGNNDESNISFKEK-SK4 (MALP2-SK4) induced B lymphocyte proliferation and TNF-α secretion in macrophages in a TLR6-independent manner as determined with cells from TLR6-deficient mice. Our results indicate that both the lipid and the N-terminal peptides of lipoproteins contribute to the specificity of recognition by TLR2 heteromers and are responsible for the ligand–receptor interaction on host cells.
-
Structure and Specific Activity of Macrophage-Stimulating Lipopeptides from Mycoplasma hyorhinis
Infection and Immunity, 1998Co-Authors: Peter F Muhlradt, Holger Meyer, Michael Kiess, Roderich D. Süssmuth, Günther JungAbstract:Mycoplasmas are potent macrophage stimulators. We describe the isolation of macrophage-stimulatory Lipopeptides S-[2,3-bisacyl(C16:0/C18:0)oxypropyl]cysteinyl-GQTDNNSSQSQQPGSGTTNT and S-[2,3-bisacyl(C16:0/C18:0)oxypropyl]cysteinyl-GQTN derived from the Mycoplasma hyorhinis variable lipoproteins VlpA and VlpC, respectively. These Lipopeptides were characterized by amino acid sequence and composition analysis and by mass spectrometry. The Lipopeptides S-[2,3-bis(palmitoyloxy)propyl]cysteinyl-GQTNT and S-[2,3-bis(palmitoyloxy)propyl]cysteinyl-SKKKK and the N-palmitoylated derivative of the latter were synthesized, and their macrophage-stimulatory activities were compared in a nitric oxide release assay with peritoneal macrophages from C3H/HeJ mice. The Lipopeptides with the free amino terminus showed half-maximal activity at 3 pM regardless of their amino acid sequence; i.e., they were as active as the previously isolated M. fermentans-derived lipopeptide MALP-2. The macrophage-stimulatory activity of the additionally N-palmitoylated lipopeptide or of the murein lipoprotein from Escherichia coli, however, was lower by orders of magnitude. It is concluded that the lack of N-acyl groups in mycoplasmal lipoproteins explains their exceptionally high in vitro macrophage-stimulatory capacity. Certain features that lipopolysaccharide endotoxin and mycoplasmal Lipopeptides have in common are discussed. Lipoproteins and Lipopeptides are likely to be the main causative agents of inflammatory reactions to mycoplasmas. This may be relevant in the context of mycoplasmas as arthritogenic pathogens and their association with AIDS.
Osamu Takeuchi - One of the best experts on this subject based on the ideXlab platform.
-
Recognition of Lipopeptides by Toll-like receptors:
Journal of Endotoxin Research, 2002Co-Authors: Kiyoshi Takeda, Osamu TakeuchiAbstract:Toll-like receptors (TLRs) recognize specific molecular patterns present only in micro-organisms and thereby activate innate immune cells. TLR2 is essential for the recognition of peptidoglycan and lipoprotein/Lipopeptides. Lipoprotein/Lipopeptides are observed in cell walls of a variety of micro-organisms. Host immune cells recognize the specific patterns of lipoprotein/Lipopeptides through the association of TLR2 with other TLRs. TLR1 and TLR6 are highly homologous to TLR2 in structure. TLR6-deficient mice showed an impaired response to mycoplasmal Lipopeptides that are diacylated, whereas TLR1-deficient mice were defective in their response to bacterial Lipopeptides that are triacylated. TLR2-deficient mice did not show any inflammatory response to either type of lipopeptide. The functional association of TLR2 with TLR1 or TLR6 has been demonstrated. Thus, TLR1 and TLR6 are involved in the discrimination of a subtle difference between triacyl and diacyl Lipopeptides through interaction with TLR2.
-
cutting edge role of toll like receptor 1 in mediating immune response to microbial lipoproteins
Journal of Immunology, 2002Co-Authors: Osamu Takeuchi, Z. Dong, Takao Horiuchi, Shintaro Sato, Katsuaki Hoshino, Kiyoshi Takeda, Robert L ModlinAbstract:The Toll-like receptor (TLR) family acts as pattern recognition receptors for pathogen-specific molecular patterns (PAMPs). TLR2 is essential for the signaling of a variety of PAMPs, including bacterial lipoprotein/Lipopeptides, peptidoglycan, and GPI anchors. TLR6 associates with TLR2 and recognizes diacylated mycoplasmal lipopeptide along with TLR2. We report here that TLR1 associates with TLR2 and recognizes the native mycobacterial 19-kDa lipoprotein along with TLR2. Macrophages from TLR1-deficient (TLR1 −/− ) mice showed impaired proinflammatory cytokine production in response to the 19-kDa lipoprotein and a synthetic triacylated lipopeptide. In contrast, TLR1 −/− cells responded normally to diacylated lipopeptide. TLR1 interacts with TLR2 and coexpression of TLR1 and TLR2 enhanced the NF-κB activation in response to a synthetic lipopeptide. Furthermore, lipoprotein analogs whose acylation was modified were preferentially recognized by TLR1. Taken together, TLR1 interacts with TLR2 to recognize the lipid configuration of the native mycobacterial lipoprotein as well as several triacylated Lipopeptides.
Valérie Leclère - One of the best experts on this subject based on the ideXlab platform.
-
Lipopeptide biodiversity in antifungal Bacillus strains isolated from Algeria
Archives of Microbiology, 2018Co-Authors: Lamia Abdellaziz, Gabrielle Chataigné, Marlène Chollet, Ahmed Abderrahmani, Lamia Yaici, Anthony Arguelles Arias, Max Béchet, Valérie Leclère, Philippe JacquesAbstract:Several Bacillus strains have been well studied for their ability to control soil-borne plant diseases. This property is linked to the production of several families of Lipopeptides. Depending of their structure, these compounds show antifungal and/or plant systemic resistance inducing activities. In this work, the biodiversity of Lipopeptides produced by different antifungal Bacillus strains isolated from seeds, rhizospheric, and non-rhizospheric soils in Algeria was analyzed. Sixteen active strains were characterized by PCR for their content in genes involved in lipopeptide biosynthesis and by MALDI-ToF for their lipopeptide production, revealing a high biodiversity of products. The difficulty to detect kurstakin genes led us to design two new sets of specific primers. An interesting potential of antifungal activity and the synthesis of two forms of fengycins differing in the eighth amino acid (Gln/Glu) were found from the strain 8. Investigation of its genome led to the finding of an adenylation domain of the fengycin synthetase predicted to activate the glutamate residue instead of the glutamine one. According to the comparison of both the results of MALDI-ToF-MS and genome analysis, it was concluded that this adenylation domain could activate both residues at the same time. This study highlighted that the richness of the Algerian ecosystems in Bacillus strains is able to produce: surfactin, pumilacidin, lichenysin, kurstakin, and different types of fengycins.
-
Bioinformatics tools for the discovery of new Lipopeptides with biocontrol applications
European Journal of Plant Pathology, 2018Co-Authors: Maude Pupin, Areski Flissi, Philippe Jacques, Valérie LeclèreAbstract:As conventional or chemical pesticides have negative impact on environment and health of both farmer and consumers, it becomes relevant to develop alternative solutions to limit their use. In this context, innovative strategies to accelerate the development of biocontrol agents are welcome. For a decade of years, it has been demonstrated that Lipopeptides are very efficient weapons against fungi responsible for crop diseases. Lipopeptides are secondary metabolites, produced by many microorganisms including beneficial rhizobacteria. The lipopeptide biosynthetic pathways include nonribosomal peptide synthetases. These modular enzymatic complexes work as assembly lines to build the peptides step by step, leading to the production of original peptide compounds with specific features as the presence of non proteinogenic monomers and cyclic and branched structures. In this paper, Florine and Norine bioinformatics tools, especially dedicated to non-ribosomal synthetases and their products are presented. Their use is mainly focused on the discovery of Lipopeptides produced by Bacillus or Pseudomonas because they seem to represent a versatile reservoir of active secondary metabolites with promising activities for applications in phytosanitary area.
-
Burkholderia genome mining for nonribosomal peptide synthetases reveals a great potential for novel siderophores and Lipopeptides synthesis
MicrobiologyOpen, 2016Co-Authors: Qassim Esmaeel, Gabrielle Chataigné, Maude Pupin, Nam Phuong Kieu, Jovana Deravel, Fabrice Krier, Monica Hofte, Max Béchet, Philippe Jacques, Valérie LeclèreAbstract:Burkholderia is an important genus encompassing a variety of species, including pathogenic strains as well as strains that promote plant growth. We have carried out a global strategy, which combined two complementary approaches. The first one is genome guided with deep analysis of genome sequences and the second one is assay guided with experiments to support the predictions obtained in silico. This efficient screening for new secondary metabolites, performed on 48 gapless genomes of Burkholderia species, revealed a total of 161 clusters containing nonribosomal peptide synthetases (NRPSs), with the potential to synthesize at least 11 novel products. Most of them are siderophores or Lipopeptides, two classes of products with potential application in biocontrol. The strategy led to the identification, for the first time, of the cluster for cepaciachelin biosynthesis in the genome of Burkholderia ambifaria AMMD and a cluster corresponding to a new malleobactin-like siderophore, called phymabactin, was identified in Burkholderia phymatum STM815 genome. In both cases, the siderophore was produced when the strain was grown in iron-limited conditions. Elsewhere, the cluster for the antifungal burkholdin was detected in the genome of B. ambifaria AMMD and also Burkholderia sp. KJ006. Burkholderia pseudomallei strains harbor the genetic potential to produce a novel lipopeptide called burkhomycin, containing a peptidyl moiety of 12 monomers. A mixture of Lipopeptides produced by Burkholderia rhizoxinica lowered the surface tension of the supernatant from 70 to 27 mN·m−1. The production of nonribosomal secondary metabolites seems related to the three phylogenetic groups obtained from 16S rRNA sequences. Moreover, the genome-mining approach gave new insights into the nonribosomal synthesis exemplified by the identification of dual C/E domains in lipopeptide NRPSs, up to now essentially found in Pseudomonas strains.
-
Identification and biochemical characteristics of Lipopeptides from Bacillus mojavensis A21
Process Biochemistry, 2014Co-Authors: Hanen Ben Ayed, Gabrielle Chataigné, Marlène Chollet, Noomen Hmidet, Max Béchet, Valérie Leclère, Philippe Jacques, Moncef NasriAbstract:Abstract This study reports the potential of a marine bacterium, Bacillus mojavensis A21, to produce lipopeptide biosurfactants. The crude lipopeptide mixture was found to be very effective in reducing surface tension to 31 mN m −1 . PCR experiments using degenerate primers revealed the presence of nonribosomal peptide synthetases genes implied in the biosyntheses of fengycin and surfactin. Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) performed on whole cells of B. mojavensis A21 confirmed the presence of Lipopeptides identified as members of surfactin and fengycin families. Further, a detailed analysis performed by MALDI-TOF-TOF revealed the presence of pumilacidin compounds. The crude lipopeptide mixture was tested for its inhibitory activity against Gram-positive and Gram-negative bacteria, and fungal strains. It was found to display significant antimicrobial activity. Strain A21 lipopeptide mixture was insensitive to proteolytic enzymes, stable between pH 3.0 and 11.0, and resistant to high temperature. Production of Lipopeptides is a characteristic of several Bacillus species, but to our knowledge this is the first report involving identification of pumilacidin, surfactin and fengycin isoforms in a B. mojavensis strain.
-
New Linear Lipopeptides Produced by Pseudomonas cichorii SF1-54 Are Involved in Virulence, Swarming Motility, and Biofilm Formation
Molecular Plant-Microbe Interactions, 2013Co-Authors: Ellen Pauwelyn, Marc Ongena, Valérie Leclère, Philippe Jacques, Chien-jui Huang, Peter Bleyaert, Herbert Budzikiewicz, Mathias Schäfer, Monica HofteAbstract:Pseudomonas cichorii is the causal agent of lettuce midrib rot, characterized by a dark-brown to green-black discoloration of the midrib. Formation of necrotic lesions by several plant-pathogenic pseudomonads is associated with production of phytotoxic Lipopeptides, which contribute to virulence. Therefore, the ability of P. cichorii SF1-54 to produce Lipopeptides was investigated. A cell-free culture filtrate of SF1-54 showed surfactant, antimicrobial, and phytotoxic activities which are typical for Lipopeptides. High-performance liquid chromatography analysis of P. cichorii SF1-54 culture filtrate revealed the presence of seven compounds with lipopeptide characteristics. Two related Lipopeptides, named cichofactin A and B, were studied in more detail: they are linear Lipopeptides with a decanoic and dodecanoic lipid chain, respectively, connected to the N-terminus of an eight-amino-acid peptide moiety. Both cichofactins are new members of the syringafactin lipopeptide family. Furthermore, two nonribosomal peptide synthethase-encoding genes, cifA and cifB, were identified as responsible for cichofactin biosynthesis. A cifAB deletion mutant no longer produced cichofactins and was impaired in swarming motility but showed enhanced biofilm formation. Upon spray inoculation on lettuce, the cichofactin-deficient mutant caused significantly less rotten midribs than the wild type, indicating that cichofactins are involved in pathogenicity of P. cichorii SF1-54. Further analysis revealed that P. cichorii isolates vary greatly in swarming motility and cichofactin production.