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Sample records for acylated homoserine lactones

  1. Imaging N-acyl homoserine lactone quorum sensing in vivo

    DEFF Research Database (Denmark)

    Christensen, Louise Dahl; van Gennip, Maria; Jakobsen, Tim Holm

    2011-01-01

    In order to study N-acyl homoserine lactone (AHL)-based quorum sensing in vivo, we present a protocol using an Escherichia coli strain equipped with a luxR-based monitor system, which in the presence of exogenous AHL molecules expresses a green fluorescent protein (GFP). Lungs from mice challenged...

  2. Profiling acylated homoserine lactones in Yersinia ruckeri and influence of exogenous acyl homoserine lactones and known quorum-sensing inhibitors on protease production

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Nielsen, Kristian Fog; Dalsgaard, Inger;

    2007-01-01

    produced at least eight different acylated homoserine lactones (AHLs) with N-(3-oxooctanoyl)-l-homoserine lactone (3-oxo-C8-HSL) being the dominant molecule. Also, some uncommon AHL, N-(3-oxoheptanoyl)-l-homoserine lactone (3-oxo-C7-HSL) and N-(3-oxononanoyl)-l-homoserine lactone (3-oxo-C9-HSL), were...... produced. 3-oxo-C8-HSL was detected in organs from fish infected with Y. ruckeri. Protease production was significantly lower at temperatures above 23 degrees C than below although growth was faster at the higher temperatures. Neither addition of sterile filtered high-density Y. ruckeri culture supernatant...

  3. Acyl-Homoserine Lactone Quorum Sensing in the Roseobacter Clade

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    Jindong Zan

    2014-01-01

    Full Text Available Members of the Roseobacter clade are ecologically important and numerically abundant in coastal environments and can associate with marine invertebrates and nutrient-rich marine snow or organic particles, on which quorum sensing (QS may play an important role. In this review, we summarize current research progress on roseobacterial acyl-homoserine lactone-based QS, particularly focusing on three relatively well-studied representatives, Phaeobacter inhibens DSM17395, the marine sponge symbiont Ruegeria sp. KLH11 and the dinoflagellate symbiont Dinoroseobacter shibae. Bioinformatic survey of luxI homologues revealed that over 80% of available roseobacterial genomes encode at least one luxI homologue, reflecting the significance of QS controlled regulatory pathways in adapting to the relevant marine environments. We also discuss several areas that warrant further investigation, including studies on the ecological role of these diverse QS pathways in natural environments.

  4. Acyl-homoserine lactone quorum sensing: from evolution to application.

    Science.gov (United States)

    Schuster, Martin; Sexton, D Joseph; Diggle, Stephen P; Greenberg, E Peter

    2013-01-01

    Quorum sensing (QS) is a widespread process in bacteria that employs autoinducing chemical signals to coordinate diverse, often cooperative activities such as bioluminescence, biofilm formation, and exoenzyme secretion. Signaling via acyl-homoserine lactones is the paradigm for QS in Proteobacteria and is particularly well understood in the opportunistic pathogen Pseudomonas aeruginosa. Despite thirty years of mechanistic research, empirical studies have only recently addressed the benefits of QS and provided support for the traditional assumptions regarding its social nature and its role in optimizing cell-density-dependent group behaviors. QS-controlled public-goods production has served to investigate principles that explain the evolution and stability of cooperation, including kin selection, pleiotropic constraints, and metabolic prudence. With respect to medical application, appreciating social dynamics is pertinent to understanding the efficacy of QS-inhibiting drugs and the evolution of resistance. Future work will provide additional insight into the foundational assumptions of QS and relate laboratory discoveries to natural ecosystems.

  5. Long Chain N-acyl Homoserine Lactone Production by Enterobacter sp. Isolated from Human Tongue Surfaces

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    Kok-Gan Chan

    2012-10-01

    Full Text Available We report the isolation of N-acyl homoserine lactone-producing Enterobacter sp. isolate T1-1 from the posterior dorsal surfaces of the tongue of a healthy individual. Spent supernatants extract from Enterobacter sp. isolate T1-1 activated the biosensor Agrobacterium tumefaciens NTL4(pZLR4, suggesting production of long chain AHLs by these isolates. High resolution mass spectrometry analysis of these extracts confirmed that Enterobacter sp. isolate T1-1 produced a long chain N-acyl homoserine lactone, namely N-dodecanoyl-homoserine lactone (C12-HSL. To the best of our knowledge, this is the first isolation of Enterobacter sp., strain T1-1 from the posterior dorsal surface of the human tongue and N-acyl homoserine lactones production by this bacterium.

  6. Thermoregulation of N-acyl homoserine lactone-based quorum sensing in the soft rot bacterium Pectobacterium atrosepticum.

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    Latour, Xavier; Diallo, Stéphanie; Chevalier, Sylvie; Morin, Danièle; Smadja, Bruno; Burini, Jean-François; Haras, Dominique; Orange, Nicole

    2007-06-01

    The psychrotolerant bacterium Pectobacterium atrosepticum produces four N-acyl homoserine lactones under a wide range of temperatures. Their thermoregulation differs from that of the exoenzyme production, described as being under quorum-sensing control. A mechanism involved in this thermoregulation consists of controlling N-acyl homoserine lactones synthase production at a transcriptional level.

  7. Synthesis of new 3-and 4-substituted analogues of acyl homoserine lactone quorum sensing autoinducers

    DEFF Research Database (Denmark)

    Olsen, Jacob Alsbæk; Severinsen, Rune Eg; Rasmussen, Thomas Bovbjerg

    2002-01-01

    The quorum sensing mechanism in Gram-negative bacteria uses small intercellular signal molecules, N-acyl-homoserine lactones (AHLs), to control transcription of specific genes in relation to population density. In this communication, we describe the parallel synthesis of new AHL analogues, in which...

  8. Synthesis of new 3- and 4-substituted analogues of acyl homoserine lactone quorum sensing autoinducers

    DEFF Research Database (Denmark)

    Olsen, J. A.; Severinsen, R.; Rasmussen, T. B.

    2002-01-01

    The quorum sensing mechanism in Gram-negative bacteria uses small intercellular signal molecules, N-acyl-homoserine lactones (AHLs), to control transcription of specific genes in relation to population density. In this communication, we describe the parallel synthesis of new AHL analogues, in which...

  9. Acyl-homoserine lactones suppresses IEC-6 cell proliferation and increase permeability of isolated rat colon.

    Science.gov (United States)

    Joe, Ga-Hyun; Andoh, Midori; Nomura, Mikako; Iwaya, Hitoshi; Lee, Jae-Sung; Shimizu, Hidehisa; Tsuji, Youhei; Maseda, Hideaki; Miyazaki, Hitoshi; Hara, Hiroshi; Ishizuka, Satoshi

    2014-01-01

    We investigated to determine whether a variety of acyl-homoserine lactones (AHLs) influences epithelial cell proliferation and mucosal permeability. 3-Oxo-C12-homoserine lactone (HSL) and 3-oxo-C14-HSL significantly suppressed IEC-6 cell proliferation. A significant increase in mucosal permeability was observed in isolated rat colon tissue exposed to C12-HSL, 3-oxo-C12-HSL, and 3-oxo-C14-HSL. These data indicate that AHLs suppress epithelial proliferation and disrupt barrier function in intestinal mucosa.

  10. Pseudomonas cremoricolorata Strain ND07 Produces N-acyl Homoserine Lactones as Quorum Sensing Molecules

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    Nina Yusrina Muhamad Yunos

    2014-06-01

    Full Text Available Quorum sensing (QS is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs. We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-l-homoserine lactone (C8-HSL and N-decanoyl-l-homoserine lactone (C10-HSL. To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

  11. Nitrite-Oxidizing Bacterium Nitrobacter winogradskyi Produces N-Acyl-Homoserine Lactone Autoinducers.

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    Mellbye, Brett L; Bottomley, Peter J; Sayavedra-Soto, Luis A

    2015-09-01

    Nitrobacter winogradskyi is a chemolithotrophic bacterium that plays a role in the nitrogen cycle by oxidizing nitrite to nitrate. Here, we demonstrate a functional N-acyl-homoserine lactone (acyl-HSL) synthase in this bacterium. The N. winogradskyi genome contains genes encoding a putative acyl-HSL autoinducer synthase (nwi0626, nwiI) and a putative acyl-HSL autoinducer receptor (nwi0627, nwiR) with amino acid sequences 38 to 78% identical to those in Rhodopseudomonas palustris and other Rhizobiales. Expression of nwiI and nwiR correlated with acyl-HSL production during culture. N. winogradskyi produces two distinct acyl-HSLs, N-decanoyl-l-homoserine lactone (C10-HSL) and a monounsaturated acyl-HSL (C10:1-HSL), in a cell-density- and growth phase-dependent manner, during batch and chemostat culture. The acyl-HSLs were detected by bioassay and identified by ultraperformance liquid chromatography with information-dependent acquisition mass spectrometry (UPLC-IDA-MS). The C=C bond in C10:1-HSL was confirmed by conversion into bromohydrin and detection by UPLC-IDA-MS.

  12. Transcriptome analysis of acyl-homoserine lactone-based quorum sensing regulation in Yersinia pestis [corrected].

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    LaRock, Christopher N; Yu, Jing; Horswill, Alexander R; Parsek, Matthew R; Minion, F Chris

    2013-01-01

    The etiologic agent of bubonic plague, Yersinia pestis, senses self-produced, secreted chemical signals in a process named quorum sensing. Though the closely related enteric pathogen Y. pseudotuberculosis uses quorum sensing system to regulate motility, the role of quorum sensing in Y. pestis has been unclear. In this study we performed transcriptional profiling experiments to identify Y. pestis quorum sensing regulated functions. Our analysis revealed that acyl-homoserine lactone-based quorum sensing controls the expression of several metabolic functions. Maltose fermentation and the glyoxylate bypass are induced by acyl-homoserine lactone signaling. This effect was observed at 30°C, indicating a potential role for quorum sensing regulation of metabolism at temperatures below the normal mammalian temperature. It is proposed that utilization of alternative carbon sources may enhance growth and/or survival during prolonged periods in natural habitats with limited nutrient sources, contributing to maintenance of plague in nature.

  13. Transcriptome analysis of acyl-homoserine lactone-based quorum sensing regulation in Yersinia pestis [corrected].

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    Christopher N LaRock

    Full Text Available The etiologic agent of bubonic plague, Yersinia pestis, senses self-produced, secreted chemical signals in a process named quorum sensing. Though the closely related enteric pathogen Y. pseudotuberculosis uses quorum sensing system to regulate motility, the role of quorum sensing in Y. pestis has been unclear. In this study we performed transcriptional profiling experiments to identify Y. pestis quorum sensing regulated functions. Our analysis revealed that acyl-homoserine lactone-based quorum sensing controls the expression of several metabolic functions. Maltose fermentation and the glyoxylate bypass are induced by acyl-homoserine lactone signaling. This effect was observed at 30°C, indicating a potential role for quorum sensing regulation of metabolism at temperatures below the normal mammalian temperature. It is proposed that utilization of alternative carbon sources may enhance growth and/or survival during prolonged periods in natural habitats with limited nutrient sources, contributing to maintenance of plague in nature.

  14. Production of acylated homoserine lactones by psychrotrophic members of the Enterobacteriaceae isolated from foods

    DEFF Research Database (Denmark)

    Gram, Lone; Christensen, A.B.; Flodgaard, Lars

    1999-01-01

    Bacteria are able to communicate and gene regulation can be mediated through the production of acylated homoserine lactone (AHL) signal molecules. These signals play important roles in several pathogenic and symbiotic bacteria. The following study was undertaken to investigate whether AHLs...... of indigenous Enterobacteriaceae reached 106 CFU/g. This level of Enterobacteriaceae is often found in lightly preserved foods, and AHL-mediated gene regulation may play a role in bacteria associated with food spoilage or food toxicity...

  15. Synthesis of new 3-and 4-substituted analogues of acyl homoserine lactone quorum sensing autoinducers

    DEFF Research Database (Denmark)

    Olsen, Jacob Alsbæk; Severinsen, Rune Eg; Rasmussen, Thomas Bovbjerg

    2002-01-01

    The quorum sensing mechanism in Gram-negative bacteria uses small intercellular signal molecules, N-acyl-homoserine lactones (AHLs), to control transcription of specific genes in relation to population density. In this communication, we describe the parallel synthesis of new AHL analogues, in whi...... substituents have been introduced into the 3- and 4-positions of the lactone ring. These analogues have been screened for their ability to activate and inhibit a Vibrio fischeri LuxI/LuxR-derived quorum sensing reporter system....

  16. Synthesis of new 3- and 4-substituted analogues of acyl homoserine lactone quorum sensing autoinducers

    DEFF Research Database (Denmark)

    Olsen, J. A.; Severinsen, R.; Rasmussen, T. B.

    2002-01-01

    The quorum sensing mechanism in Gram-negative bacteria uses small intercellular signal molecules, N-acyl-homoserine lactones (AHLs), to control transcription of specific genes in relation to population density. In this communication, we describe the parallel synthesis of new AHL analogues, in whi...... substituents have been introduced into the 3- and 4-positions of the lactone ring. These analogues have been screened for their ability to activate and inhibit a Vibrio fischeri LuxI/LuxR-derived quorum sensing reporter system. © 2002 Elsevier Science Ltd. All rights reserved....

  17. Positive Autoregulation of an Acyl-Homoserine Lactone Quorum-Sensing Circuit Synchronizes the Population Response.

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    Scholz, Rebecca L; Greenberg, E Peter

    2017-07-25

    Many proteobacteria utilize acyl-homoserine lactone quorum-sensing signals. At low population densities, cells produce a basal level of signal, and when sufficient signal has accumulated in the surrounding environment, it binds to its receptor, and quorum-sensing-dependent genes can be activated. A common characteristic of acyl-homoserine lactone quorum sensing is that signal production is positively autoregulated. We have examined the role of positive signal autoregulation in Pseudomonas aeruginosa We compared population responses and individual cell responses in populations of wild-type P. aeruginosa to responses in a strain with the signal synthase gene controlled by an arabinose-inducible promoter so that signal was produced at a constant rate per cell regardless of cell population density. At a population level, responses of the wild type and the engineered strain were indistinguishable, but the responses of individual cells in a population of the wild type showed greater synchrony than the responses of the engineered strain. Although sufficient signal is required to activate expression of quorum-sensing-regulated genes, it is not sufficient for activation of certain genes, the late genes, and their expression is delayed until other conditions are met. We found that late gene responses were reduced in the engineered strain. We conclude that positive signal autoregulation is not a required element in acyl-homoserine lactone quorum sensing, but it functions to enhance synchrony of the responses of individuals in a population. Synchrony might be advantageous in some situations, whereas a less coordinated quorum-sensing response might allow bet hedging and be advantageous in other situations.IMPORTANCE There are many quorum-sensing systems that involve a transcriptional activator, which responds to an acyl-homoserine lactone signal. In all of the examples studied, the gene coding for signal production is positively autoregulated by the signal, and it has even

  18. Production of N-acyl homoserine lactones by the sponge-associated marine actinobacteria Salinispora arenicola and Salinispora pacifica.

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    Bose, Utpal; Ortori, Catharine A; Sarmad, Sarir; Barrett, David A; Hewavitharana, Amitha K; Hodson, Mark P; Fuerst, John A; Shaw, P Nicholas; Boden, Rich

    2017-01-01

    The structures of acyl homoserine lactone (AHL) compounds and their quantification were accomplished using an integrated liquid chromatography-mass spectrometry approach. The precursor and product ions, along with retention times of peaks, were searched against an in-house database of AHLs and structures confirmed by accurate mass and by comparison with authentic AHL standards. The two compounds, N-(3-oxodecanoyl)-L-homoserine lactone and N-(3-oxododecanoyl)-L-homoserine lactone, were characterised and quantified in Salinispora sp. cultures. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. gfp-based N-acyl homoserine-lactone sensor systems for detection of bacterial communication

    DEFF Research Database (Denmark)

    Andersen, Jens Bo; Heydorn, Arne; Hentzer, Morten

    2001-01-01

    In order to perform single-cell analysis and online studies of N-acyl homoserine lactone (AHL)-mediated communication among bacteria, components of the Vibrio fischeri quorum sensor encoded by luxR-P-luxI have been fused to modified versions of gfpmut3* genes encoding unstable green fluorescent...... detection at the single-cell level and allowed for real-time measurements of fluctuations in AHL concentrations. This green fluorescent AHL sensor provides a state-of-the art tool for studies of communication between the individuals present in mixed bacterial communities....... proteins. Bacterial strains harboring this green fluorescent sensor detected a broad spectrum of AHL molecules and were capable of sensing the presence of 5 nM N-3-oxohexanoyl-L-homoserine lactone in the surroundings. In combination with epifluorescent microscopy, the sensitivity of the sensor enabled AHL...

  20. Small-molecule inhibitor binding to an N-acyl-homoserine lactone synthase.

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    Chung, Jiwoung; Goo, Eunhye; Yu, Sangheon; Choi, Okhee; Lee, Jeehyun; Kim, Jinwoo; Kim, Hongsup; Igarashi, Jun; Suga, Hiroaki; Moon, Jae Sun; Hwang, Ingyu; Rhee, Sangkee

    2011-07-19

    Quorum sensing (QS) controls certain behaviors of bacteria in response to population density. In gram-negative bacteria, QS is often mediated by N-acyl-L-homoserine lactones (acyl-HSLs). Because QS influences the virulence of many pathogenic bacteria, synthetic inhibitors of acyl-HSL synthases might be useful therapeutically for controlling pathogens. However, rational design of a potent QS antagonist has been thwarted by the lack of information concerning the binding interactions between acyl-HSL synthases and their ligands. In the gram-negative bacterium Burkholderia glumae, QS controls virulence, motility, and protein secretion and is mediated by the binding of N-octanoyl-L-HSL (C8-HSL) to its cognate receptor, TofR. C8-HSL is synthesized by the acyl-HSL synthase TofI. In this study, we characterized two previously unknown QS inhibitors identified in a focused library of acyl-HSL analogs. Our functional and X-ray crystal structure analyses show that the first inhibitor, J8-C8, binds to TofI, occupying the binding site for the acyl chain of the TofI cognate substrate, acylated acyl-carrier protein. Moreover, the reaction byproduct, 5'-methylthioadenosine, independently binds to the binding site for a second substrate, S-adenosyl-L-methionine. Closer inspection of the mode of J8-C8 binding to TofI provides a likely molecular basis for the various substrate specificities of acyl-HSL synthases. The second inhibitor, E9C-3oxoC6, competitively inhibits C8-HSL binding to TofR. Our analysis of the binding of an inhibitor and a reaction byproduct to an acyl-HSL synthase may facilitate the design of a new class of QS-inhibiting therapeutic agents.

  1. A novel bioassay for high-throughput screening microorganisms with N-acyl homoserine lactone degrading activity.

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    Liu, Pengfu; Gao, Yang; Huang, Wei; Shao, Zongze; Shi, Jiping; Liu, Ziduo

    2012-05-01

    A novel biosensor strain (Escherichia coli ALM403) that responded to N-acyl homoserine lactone (AHL) was constructed using a luxR-Plux cassette as a regulatory sequence and β-mannanase as a reporter gene. Dinitrosalicylic acid method was used to detect the response of the sensor strain to N-acyl homoserine lactone. By investigating the response to a range of concentrations of N-β-oxooctanoyl-L-homoserine lactone (OOHL), it was demonstrated that the expression of mannanase in E. coli ALM403 could be greatly enhanced by OOHL and resulted in an assayable phenotype. A high-throughput screening approach was developed to isolate AHL-degrading microorganisms, and a marine Halomonas sp. S66-4 showing a marked AHL-degrading ability was successfully isolated. In conclusion, the bioassay system provided a simple and efficient approach to isolate AHL-degrading bacteria.

  2. Quorum sensing signal molecules (acylated homoserine lactones) in Gram-negative fish pathogenic bacteria

    DEFF Research Database (Denmark)

    Bruhn, Jesper Bartholin; Dalsgaard, Inger; Nielsen, K.F.

    2005-01-01

    and plant-pathogenic bacteria. A total of 59 strains, representing 9 different fish pathogenic species, were tested against 2 AHL monitor bacteria (Agrobacterium tumefaciens NT1 [pZLR4] and Chromobacterium violaceum CV026) in a well diffusion assay and by thin-layer chromatography (TLC). Representative...... salmonicida and Vibrio splendidus were also positive. Aeromonas species produced N-butanoyl homoserine lactone (BHL) and N-hexanoyl homoserine lactone (HHL) and 1 additional product, whereas N-3-oxo-hexanoyl homoserine lactone (OHHL) and HHL were detected in Vibrio salmonicida. N-3-oxo-octanoyl homoserine...... lactone (OOHL) and N-3-octanoyl homoserine lactone (OHL) were detected in Y. ruckeii. AHLs were not detected from strains of Photobacterium damselae, Flavobacterium psychrophilum or Moritella viscosa. AHLs were extracted from fish infected with Y. ruckeri but not from fish infected with A. salmonicida...

  3. Production of N-acyl-L-homoserine lactones by P. aeruginosa isolates from chronic lung infections associated with cystic fibrosis

    DEFF Research Database (Denmark)

    Geisenberger, O; Givskov, M; Riedel, K;

    2000-01-01

    The N-acyl-L-homoserine lactones (AHLs) produced by sequential Pseudomonas aeruginosa isolates from chronically infected patients with cystic fibrosis were analyzed by thin-layer chromatography. It is demonstrated that both the amounts and the types of molecules synthesized by isolates from...

  4. Production of acylated homoserine lactone by gram-positive bacteria isolated from marine water.

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    Biswa, Pramal; Doble, Mukesh

    2013-06-01

    Acylated homoserine lactone (AHL)-based quorum sensing (QS) has been reported to be present only in Gram-negative microorganisms. Isolation of a novel Gram-positive microorganism from sea water, capable of producing AHL, is reported here. The isolate (GenBank: JF915892, designated as MPO) belonging to the Exiguobacterium genera is capable of inducing the AHL bioreporters, namely Chromobacterium violaceum CV026, Agrobacterium tumefaceins A136, and E. coli JM 109(psb1075). This inducer is characterized as C3-oxo-octanoyl homoserine lactone (OOHL), and its production reaches a maximum of 15.6 μg L(-1), during the stationary growth phase of the organism. MPO extract when exogenously added inhibits the formation of biofilm for the same organism and lowers the extracellular polymeric substances, indicating an AHL-associated phenotypic trait. The isolated sequence of a probable LuxR homolog from MPO (designated as ExgR) shows similar functional domains and contains conserved residues in LuxR from other known bacterial QS LuxR regulators. Also present immediately downstream to ExgR was found a sequence showing homology to known LuxI synthase of Pseudomonas putida. qPCR analysis suggests an increment in exgR mRNA on addition of AHL, further proving the role of ExgR as a QS regulator.

  5. Production of acylated homoserine lactones by psychrotrophic members of the Enterobacteriaceae isolated from foods

    DEFF Research Database (Denmark)

    Gram, Lone; Christensen, A.B.; Flodgaard, Lars

    1999-01-01

    Bacteria are able to communicate and gene regulation can be mediated through the production of acylated homoserine lactone (AHL) signal molecules. These signals play important roles in several pathogenic and symbiotic bacteria. The following study was undertaken to investigate whether AHLs...... are produced by bacteria found in food at temperatures and NaCl conditions commercially used for food preservation and storage. A minimum of 116 of 154 psychrotrophic Enterobacteriaceae strains isolated from cold-smoked salmon or vacuum-packed chilled meat produced AHLs. Analysis by thin-layer chromatography...... of indigenous Enterobacteriaceae reached 106 CFU/g. This level of Enterobacteriaceae is often found in lightly preserved foods, and AHL-mediated gene regulation may play a role in bacteria associated with food spoilage or food toxicity...

  6. Pantoea sp. isolated from tropical fresh water exhibiting N-acyl homoserine lactone production.

    Science.gov (United States)

    Tan, Wen-Si; Muhamad Yunos, Nina Yusrina; Tan, Pui-Wan; Mohamad, Nur Izzati; Adrian, Tan-Guan-Sheng; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    N-Acyl homoserine lactone (AHL) serves as signaling molecule for quorum sensing (QS) in Gram-negative bacteria to regulate various physiological activities including pathogenicity. With the aim of isolating freshwater-borne bacteria that can cause outbreak of disease in plants and portrayed QS properties, environmental water sampling was conducted. Here we report the preliminary screening of AHL production using Chromobacterium violaceum CV026 and Escherichia coli [pSB401] as AHL biosensors. The 16S rDNA gene sequence of isolate M009 showed the highest sequence similarity to Pantoea stewartii S9-116, which is a plant pathogen. The isolated Pantoea sp. was confirmed to produce N-3-oxohexanoyl-L-HSL (3-oxo-C6-HSL) through analysis of high resolution mass tandem mass spectrometry.

  7. Endophytic actinomycetes: a novel source of potential acyl homoserine lactone degrading enzymes.

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    Chankhamhaengdecha, Surang; Hongvijit, Suphatra; Srichaisupakit, Akkaraphol; Charnchai, Pattra; Panbangred, Watanalai

    2013-01-01

    Several Gram-negative pathogenic bacteria employ N-acyl-L-homoserine lactone (HSL) quorum sensing (QS) system to control their virulence traits. Degradation of acyl-HSL signal molecules by quorum quenching enzyme (QQE) results in a loss of pathogenicity in QS-dependent organisms. The QQE activity of actinomycetes in rhizospheric soil and inside plant tissue was explored in order to obtain novel strains with high HSL-degrading activity. Among 344 rhizospheric and 132 endophytic isolates, 127 (36.9%) and 68 (51.5%) of them, respectively, possessed the QQE activity. The highest HSL-degrading activity was at 151.30 ± 3.1 nmole/h/mL from an endophytic actinomycetes isolate, LPC029. The isolate was identified as Streptomyces based on 16S  rRNA gene sequence similarity. The QQE from LPC029 revealed HSL-acylase activity that was able to cleave an amide bond of acyl-side chain in HSL substrate as determined by HPLC. LPC029 HSL-acylase showed broad substrate specificity from C6- to C12-HSL in which C10HSL is the most favorable substrate for this enzyme. In an in vitro pathogenicity assay, the partially purified HSL-acylase efficiently suppressed soft rot of potato caused by Pectobacterium carotovorum ssp. carotovorum as demonstrated. To our knowledge, this is the first report of HSL-acylase activity derived from an endophytic Streptomyces.

  8. Endophytic Actinomycetes: A Novel Source of Potential Acyl Homoserine Lactone Degrading Enzymes

    Directory of Open Access Journals (Sweden)

    Surang Chankhamhaengdecha

    2013-01-01

    Full Text Available Several Gram-negative pathogenic bacteria employ N-acyl-L-homoserine lactone (HSL quorum sensing (QS system to control their virulence traits. Degradation of acyl-HSL signal molecules by quorum quenching enzyme (QQE results in a loss of pathogenicity in QS-dependent organisms. The QQE activity of actinomycetes in rhizospheric soil and inside plant tissue was explored in order to obtain novel strains with high HSL-degrading activity. Among 344 rhizospheric and 132 endophytic isolates, 127 (36.9% and 68 (51.5% of them, respectively, possessed the QQE activity. The highest HSL-degrading activity was at 151.30±3.1 nmole/h/mL from an endophytic actinomycetes isolate, LPC029. The isolate was identified as Streptomyces based on 16S  rRNA gene sequence similarity. The QQE from LPC029 revealed HSL-acylase activity that was able to cleave an amide bond of acyl-side chain in HSL substrate as determined by HPLC. LPC029 HSL-acylase showed broad substrate specificity from C6- to C12-HSL in which C10HSL is the most favorable substrate for this enzyme. In an in vitro pathogenicity assay, the partially purified HSL-acylase efficiently suppressed soft rot of potato caused by Pectobacterium carotovorum ssp. carotovorum as demonstrated. To our knowledge, this is the first report of HSL-acylase activity derived from an endophytic Streptomyces.

  9. Involvement of Acylated Homoserine Lactones (AHLs) of Aeromonas sobria in Spoilage of Refrigerated Turbot (Scophthalmus maximus L.).

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    Li, Tingting; Cui, Fangchao; Bai, Fengling; Zhao, Guohua; Li, Jianrong

    2016-07-13

    One quorum sensing strain was isolated from spoiled turbot. The species was determined by 16S rRNA gene analysis and classical tests, named Aeromonas sobria AS7. Quorum-sensing (QS) signals (N-acyl homoserine lactones (AHLs)) were detected by report strains and their structures were further determined by GC-MS. The activity changes of AHLs on strain growth stage as well as the influence of different culture conditions on secretion activity of AHLs were studied by the punch method. The result indicated that strain AS7 could induce report strains to produce typical phenotypic response. N-butanoyl-dl-homoserine lactone (C₄-HSL), N-hexanoyl-dl-homoserine lactone (C₆-HSL), N-octanoyl-dl-homoserine lactone (C₈-HSL), N-decanoyl-dl-homoserine lactone (C10-HSL), N-dodecanoyl-dl-homoserine lactone (C12-HSL) could be detected. The activities of AHLs were density-dependent and the max secretion level was at pH 8, sucrose culture, 1% NaCl and 32 h, respectively. The production of siderophore in strain AS7 was regulated by exogenous C₈-HSL, rather than C₆-HSL. Exogenous C₄-HSL and C₈-HSL accelerated the growth rate and population density of AS7 in turbot samples under refrigerated storage. However, according to the total viable counts and total volatile basic nitrogen (TVB-N) values of the fish samples, exogenous C₆-HSL did not cause spoilage of the turbot fillets. In conclusion, our results suggested that QS was involved in the spoilage of refrigerated turbot.

  10. Profile of the culturable microbiome capable of producing acyl-homoserine lactone in the tobacco phyllosphere

    Institute of Scientific and Technical Information of China (English)

    Di Lv; Anzhou Ma; Xuanming Tang; Zhihui Bai; Hongyan Qi; Guoqiang Zhuang

    2013-01-01

    Bacterial populations coexisting in the phyllosphere niche have important effects on plant health.Quorum sensing (QS) allows bacteria to communicate via diffusible signal molecules,but QS-dependent behaviors in phyllosphere bacterial populations are poorly understood.We investigate the dense and diverse N-acyl-homoserine lactone (AHL)-producing phyllosphere bacteria living on tobacco leaf surfaces via a culture-dependent method and 16S rRNA gene sequencing.Our results indicated that approximately 7.9%-11.7%of the culturable leaf-associated bacteria have the ability to produce AHL based on the assays using whole-cell biosensors.Sequencing of the 16S rRNA gene assigned the AHL-producing strains to two phylogenetic groups,with Gammaproteobacteria (93%) as the predominant group,followed by Alphaproteobacteria.All of the AHL-producing Alphaproteobacteria were affiliated with the genus Rhizobium,whereas the AHL-producing bacteria belonging to the Gammaproteobacteria mainly fell within the genera Pseudomonas,Acinetobacter,Citrobacter,Enterobacter,Pantoea and Serratia.The bioassays of supernatant extracts revealed that a portion of the strains have a remarkable AHL profile for AHL induction activity using the two different biosensors,and one compound in the active extract of a representative isolate,NTL223,corresponded to 3-oxo-hexanoyl-homoserine lactone.A large population size and diversity of bacteria capable of AHL-driven QS were found to cohabit on leaves,implying that cross-communication based AHL-type QS may be common in the phyllosphere.Furthermore,this study provides a general snapshot of a potential valuable application of AHL-producing bacteria inhabiting leaves for their presumable ecological roles in the phyllosphere.

  11. Profile of Citrobacter freundii ST2, a Multi-acyl-homoserine Lactone Producer Associated with Marine Dinoflagellates.

    Science.gov (United States)

    Huang, Xinqi; Gao, Yan; Ma, Zhiping; Lin, Guanghui; Cai, Zhonghua; Zhou, Jin

    2017-01-01

    Marine algae provide a unique niche termed the phycosphere for microorganism inhabitation. The phycosphere environment is an important niche for mutualistic and competitive interactions between algae and bacteria. Quorum sensing (QS) serves as a gene regulatory system in the microbial biosphere that allows bacteria to sense the population density with signaling molecules, such as acyl-homoserine lactone (AHL), and adapt their physiological activities to their surroundings. Understanding the QS system is important to elucidate the interactions between algal-associated microbial communities in the phycosphere condition. In this study, we isolated an epidermal bacterium (ST2) from the marine dinoflagellate Scrippsiella trochoidea and evaluated its AHL production profile. Strain ST2 was classified as a member of the genus Citrobacter closely related to Citrobacter freundii by 16S rRNA gene sequence analysis. Thin-layer chromatography revealed that C. freundii ST2 secreted three active AHL compounds into the culture supernatant. Specific compounds, such as N-butyryl-L-homoserine lactone (C4-AHL), N-octanoyl-DL-homoserine lactone (C8-AHL), and N-decanoyl-DL-homoserine lactone (C10-AHL), were identified by high-resolution tandem mass spectrometry. Carbon metabolic profiling with Biolog EcoPlate™ indicated that C. freundii ST2 was widely used as a carbon source and preferred carbohydrates, amino acids, and carboxylic acids as carbon substrates. Our results demonstrated that C. freundii ST2 is a multi-AHL producer that participates in the phycosphere carbon cycle.

  12. Proteomic assessment of the role of N-acyl homoserine lactone in Shewanella putrefaciens spoilage.

    Science.gov (United States)

    Zhang, Caili; Zhu, Suqin; Jatt, Abdul-Nabi; Pan, Yurong; Zeng, Mingyong

    2017-08-21

    Shewanella spp. are the common spoilage organisms found in aquatic food products stored at low temperature and their spoilage mechanism has been reported to be mediated by quorum sensing (QS). However, the specifically expressed proteins responding to N-acyl homoserine-lactone (AHLs) were seldom reported. The present study aims to evaluate the effects of different AHL signal molecules on Shewanella putrefaciens Z4 isolated from refrigerated turbot (Scophthalmus maximus) at the proteome level. The results revealed that exogenous AHLs were utilized as QS signal molecules by S. putrefaciens Z4, and AHLs were not degraded by intracellular or extracellular enzymes secreted by S. putrefaciens Z4. Twenty-three differently expressed spots upon the addition of AHLs were selected and identified by liquid chromatography-mass spectrometry (LC-MS). The results indicated that proteins involving in growth and metabolism (i.e., citrate synthase, succinate semialdehyde dehydrogenase), environment adaptation and regulators (i.e., polysaccharide deacetylases, transaldolase) were down-regulated upon three kinds of AHLs (C4-HSL, C6-HSL, and O-C6-HSL), whereas the abundance of stress response protein and DNA ligase were elevated by the addition of exogenous AHLs. Moreover, the effects of exogenous C6-HSL and O-C6-HSLwere prominent. These results provide evidence that AHL-based QS signal molecules affected some important metabolic properties of S. putrefaciens. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  13. Topical Administration of Acylated Homoserine Lactone Improves Epithelialization of Cutaneous Wounds in Hyperglycaemic Rats.

    Directory of Open Access Journals (Sweden)

    Lijuan Huang

    Full Text Available Clinicians often experience delayed epithelialization in diabetic patients, for which a high glucose condition is one of the causes. However, the mechanisms underlying delayed wound closure have not been fully elucidated, and effective treatments to enhance epithelialization in patients with hyperglycaemia have not been established. Here we propose a new reagent, acylated homoserine lactone (AHL, to improve the delayed epithelialization due to the disordered formation of a basement membrane of epidermis in hyperglycaemic rats. Acute hyperglycaemia was induced by streptozotocin injection in this experiment. Full thickness wounds were created on the flanks of hyperglycaemic or control rats. Histochemical and immunohistochemical analyses were performed to identify hyperglycaemia-specific abnormalities in epidermal regeneration by comparison between groups. We then examined the effects of AHL on delayed epithelialization in hyperglycaemic rats. Histological analysis showed the significantly shorter epithelializing tissue (P < 0.05, abnormal structure of basement membrane (fragmentation and immaturity, and hypo- and hyperproliferation of basal keratinocytes in hyperglycaemic rats. Treating the wound with AHL resulted in the decreased abnormalities of basement membrane, normal distribution of proliferating epidermal keratinocytes, and significantly promoted epithelialization (P < 0.05 in hyperglycemic rats, suggesting the improving effects of AHL on abnormal epithelialization due to hyperglycemia.

  14. N-acyl-homoserine lactones-producing bacteria protect plants against plant and human pathogens.

    Science.gov (United States)

    Hernández-Reyes, Casandra; Schenk, Sebastian T; Neumann, Christina; Kogel, Karl-Heinz; Schikora, Adam

    2014-11-01

    The implementation of beneficial microorganisms for plant protection has a long history. Many rhizobia bacteria are able to influence the immune system of host plants by inducing resistance towards pathogenic microorganisms. In this report, we present a translational approach in which we demonstrate the resistance-inducing effect of Ensifer meliloti (Sinorhizobium meliloti) on crop plants that have a significant impact on the worldwide economy and on human nutrition. Ensifer meliloti is usually associated with root nodulation in legumes and nitrogen fixation. Here, we suggest that the ability of S. meliloti to induce resistance depends on the production of the quorum-sensing molecule, oxo-C14-HSL. The capacity to enhanced resistance provides a possibility to the use these beneficial bacteria in agriculture. Using the Arabidopsis-Salmonella model, we also demonstrate that the application of N-acyl-homoserine lactones-producing bacteria could be a successful strategy to prevent plant-originated infections with human pathogens. © 2014 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  15. Effect of small chain N acyl homoserine lactone quorum sensing signals on biofilms of food-borne pathogens.

    Science.gov (United States)

    A, Jamuna Bai; V, Ravishankar Rai

    2016-09-01

    Quorum sensing or cell to cell communication which includes inter- and intra-cellular communication has been implicated in the production of virulence factor and formation of biofilm in food-borne pathogens. In the present study, the effect of quorum sensing signals on the biofilms of food-borne pathogens has been elucidated. N-butryl homoserine lactone and N-hexanoyl homoserine lactone belonging to acyl homoserine lactone (AHL) family of signaling molecules were investigated for their effect on the biofilm formation (attachment and exopolymeric substance production) in the food-borne pathogens Escherichia coli, Salmonella enterica serovar Typhimurium and Vibrio parahemolyticus. The signaling molecules at a concentration of 1 µM were capable of increasing biofilm formation in all the tested pathogens. There was an increase in the attachment of the bacterial cells and biomass as observed by microtiter plate assay and exopolymeric substances production in the biofilms in presence of the AHLs. Further, it needs to be elucidated if the effect of AHLS on the biofilms of E. coli and S. enterica serovar Typhimurium is SdiA dependent.

  16. Acyl-homoserine lactone production is more common among plant-associated Pseudomonas spp. than among soilborne Pseudomonas spp.

    Science.gov (United States)

    Elasri, M; Delorme, S; Lemanceau, P; Stewart, G; Laue, B; Glickmann, E; Oger, P M; Dessaux, Y

    2001-03-01

    A total of 137 soilborne and plant-associated bacterial strains belonging to different Pseudomonas species were tested for their ability to synthesize N-acyl-homoserine lactones (NAHL). Fifty-four strains synthesized NAHL. Interestingly, NAHL production appears to be more common among plant-associated than among soilborne Pseudomonas spp. Indeed, 40% of the analyzed Pseudomonas syringae strains produced NAHL which were identified most often as the short-chain NAHL, N-hexanoyl-L-homoserine lactone, N-(3-oxo-hexanoyl)-homoserine lactone, and N-(3-oxo-octanoyl)-L-homoserine lactone (no absolute correlation between genomospecies of P. syringae and their ability to produce NAHL could be found). Six strains of fluorescent pseudomonads, belonging to the species P. chlororaphis, P. fluorescens, and P. putida, isolated from the plant rhizosphere produced different types of NAHL. In contrast, none of the strains isolated from soil samples were shown to produce NAHL. The gene encoding the NAHL synthase in P. syringae pv. maculicola was isolated by complementation of an NAHL-deficient Chromobacterium mutant. Sequence analysis revealed the existence of a luxI homologue that we named psmI. This gene is sufficient to confer NAHL synthesis upon its bacterial host and has strong homology to psyI and ahlI, two genes involved in NAHL production in P. syringae pv. tabaci and P. syringae pv. syringae, respectively. We identified another open reading frame that we termed psmR, transcribed convergently in relation to psmI and partly overlapping psmI; this gene encodes a putative LuxR regulatory protein. This gene organization, with luxI and luxR homologues facing each other and overlapping, has been found so far only in the enteric bacteria Erwinia and Pantoea and in the related species P. syringae pv. tabaci.

  17. A high-throughput screen for quorum-sensing inhibitors that target acyl-homoserine lactone synthases.

    Science.gov (United States)

    Christensen, Quin H; Grove, Tyler L; Booker, Squire J; Greenberg, E Peter

    2013-08-20

    Many Proteobacteria use N-acyl-homoserine lactone (acyl-HSL) quorum sensing to control specific genes. Acyl-HSL synthesis requires unique enzymes that use S-adenosyl methionine as an acyl acceptor and amino acid donor. We developed and executed an enzyme-coupled high-throughput cell-free screen to discover acyl-HSL synthase inhibitors. The three strongest inhibitors were equally active against two different acyl-HSL synthases: Burkholderia mallei BmaI1 and Yersinia pestis YspI. Two of these inhibitors showed activity in whole cells. The most potent compound behaves as a noncompetitive inhibitor with a Ki of 0.7 µM and showed activity in a cell-based assay. Quorum-sensing signal synthesis inhibitors will be useful in attempts to understand acyl-HSL synthase catalysis and as a tool in studies of quorum-sensing control of gene expression. Because acyl-HSL quorum-sensing controls virulence of some bacterial pathogens, anti-quorum-sensing chemicals have been sought as potential therapeutic agents. Our screen and identification of acyl-HSL synthase inhibitors serve as a basis for efforts to target quorum-sensing signal synthesis as an antivirulence approach.

  18. N-Acyl Homoserine Lactone Production by Klebsiella pneumoniae Isolated from Human Tongue Surface

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2012-03-01

    Full Text Available Bacteria communicate by producing quorum sensing molecules called autoinducers, which include autoinducer-1, an N-hexanoyl homoserine lactone (AHL, and autoinducer-2. Bacteria present in the human oral cavity have been shown to produce autoinducer-2, but not AHL. Here, we report the isolation of two AHL-producing Klebsiella pneumoniae strains from the posterior dorsal surface of the tongue of a healthy individual. Spent culture supernatant extracts from K. pneumoniae activated the biosensors Agrobacterium tumefaciens NTL4(pZLR4 and Escherichia coli [pSB401], suggesting the presence of both long and short chain AHLs. High resolution mass spectrometry analyses of these extracts confirmed that both K. pneumoniae isolates produced N-octanoylhomoserine lactone and N-3-dodecanoyl-L-homoserine lactone. To the best of our knowledge, this is the first report of the isolation of K. pneumoniae from the posterior dorsal surface of the human tongue and the production of these AHLs by this bacterium.

  19. The quorum-quenching N-acyl homoserine lactone acylase PvdQ is an Ntn-hydrolase with an unusual substrate-binding pocket

    NARCIS (Netherlands)

    Bokhove, Marcel; Jimenez, Pol Nadal; Quax, Wim J.; Dijkstra, Bauke W.

    2010-01-01

    In many Gram-negative pathogens, their virulent behavior is regulated by quorum sensing, in which diffusible signals such as N-acyl homoserine lactones (AHLs) act as chemical messaging compounds. Enzymatic degradation of these diffusible signals by, e. g., lactonases or amidohydrolases abolishes AHL

  20. Methods for detecting acylated homoserine lactones produced by Gram-negative bacteria and their application in studies of AHL- production kinetics

    DEFF Research Database (Denmark)

    Ravn, L.; Christensen, Allan Beck; Molin, Søren

    2001-01-01

    In the process of evaluating the role of acylated homoserine lactones (AHLs) in food-spoiling Gram-negative bacteria, we have combined a range of bacterial AHL monitor systems to determine the AHL-profile and the kinetics of AHL-production. AHL production from 148 strains of Enterobacteriaceae is...

  1. Development of a dry, stable and inhalable acyl-homoserine-lactone-acylase powder formulation for the treatment of pulmonary Pseudomonas aeruginosa infections

    NARCIS (Netherlands)

    Wahjudi, Mariana; Murugappan, Senthil; van Merkerk, Ronald; Eissens, Anko C.; Visser, Marinella R.; Hinrichs, Wouter L. J.; Quax, Wim J.

    2013-01-01

    In the lungs of cystic fibrosis (CF) patients, Pseudomonas aeruginosa commonly causes chronic infections. It has been shown that the P. aeruginosa quorum sensing (QS) system controls the expression of virulence factors during invasion and infection to host cells. PvdQ is an acyl-homoserine lactone

  2. N-Acyl Homoserine Lactones in Diverse Pectobacterium and Dickeya Plant Pathogens: Diversity, Abundance, and Involvement in Virulence

    Science.gov (United States)

    Crépin, Alexandre; Beury-Cirou, Amélie; Barbey, Corinne; Farmer, Christine; Hélias, Valérie; Burini, Jean-François; Faure, Denis; Latour, Xavier

    2012-01-01

    Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-l-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens. PMID:22737020

  3. Methods for detecting acylated homoserine lactones produced by Gram-negative bacteria and their application in studies of AHL- production kinetics

    DEFF Research Database (Denmark)

    Ravn, L.; Christensen, Allan Beck; Molin, Søren

    2001-01-01

    In the process of evaluating the role of acylated homoserine lactones (AHLs) in food-spoiling Gram-negative bacteria, we have combined a range of bacterial AHL monitor systems to determine the AHL-profile and the kinetics of AHL-production. AHL production from 148 strains of Enterobacteriaceae......-oxo-hexanoyl homoserine lactone being the most prominent. it was found that the simultaneous use of monitor strains in the top-layer was necessary for the detection of (presumably) all the AHLs, An agar well-diffusion assay based on A. tumefaciens pDZLR4 was used for quantifying AHLs from bacterial supernatants...

  4. Diverse Profiles of N-acyl Homoserine L-Lactones, Biofilm, Virulence Genes and Integrons in Food-Borne Aeromonas Isolates.

    Science.gov (United States)

    Nagar, Vandan; Sinha, Vibha; Bandekar, Jayant R

    2015-08-01

    Aeromonas are regarded as opportunistic as well as primary pathogens of humans and fish, and are associated with gastroenteritis and septicemia in humans. Production of N-acyl-homoserine lactone (AHL) signal molecules and biofilm was determined in 22 Aeromonas isolates, from different food products in India, using thin-layer chromatography (TLC) analysis and microtiter-plate assay, respectively. Overall, highly heterogeneous patterns of AHL production were observed, with the production of N-butanoyl homoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL) by the majority (81.8%) of Aeromonas food isolates. Moreover, putative N-pentanoyl homoserine lactone (C5-HSL), N-heptanoyl homoserine lactone (C7-HSL), and N-octanoyl homoserine lactone (C8-HSL) were produced by 72.7%, 27.3%, and 9.1% of isolates, respectively. This is the 1st report of production of C7-HSL by Aeromonas species. Aeromonas food isolates were highly variable in their biofilm forming abilities with majority of them as weak biofilm producers in 2 different media, TSB and M9 minimal medium supplemented with 0.4% glucose. The genes encoding for putative virulence factors, glycerophospholipid cholesterol acyltransferase (gcat), heat-labile cytotonic enterotoxin (alt), heat-stable cytotonic enterotoxin (ast), serine protease (ser), polar flagella (fla), and lateral flagella (lafA) were present in 95.5%, 59.1%, 22.7%, 81.8%, 77.3%, and 22.7% of the strains, respectively. Class 1 integrons (100 to 3000 bp) were found in 68.2% of food isolates; whereas, 50% isolates contained class 2 integrons (150 to 1600 bp). This study provides a baseline data on the diversity of AHLs, biofilm forming ability and presence of virulence genes and integrons in Aeromonas food isolates from India.

  5. Pseudomonas fragi strains isolated from meat do not produce N-acyl homoserine lactones as signal molecules.

    Science.gov (United States)

    Ferrocino, Ilario; Ercolini, Danilo; Villani, Francesco; Moorhead, Sandra M; Griffiths, Mansel W

    2009-12-01

    Quorum sensing (QS) is a signalling mechanism through which bacteria cellular functions are modified to promote access to nutrients and more favorable environmental niches. The frequent occurrence of Pseudomonas spp. in fresh and spoiled meat may involve enhanced gene expression regulated by QS. Several Pseudomonas spp. produce different N-acyl homoserine lactone (AHL) signal molecules. Meat spoilage during aerobic, refrigerated storage is often associated with the presence of Pseudomonas fragi. As with other Pseudomonas species in natural habitats, the dominance and activities of P. fragi in meat may be regulated by QS. In this study, five biosensor strains were used to detect AHL production on three different media by 72 different P. fragi strains isolated from fresh and spoiled meat. Positive and negative AHL-producing strains were used to verify the assays. None of the strains produced detectable quantities of AHLs, even when concentrated cell-free culture supernatants were assayed, nor did exogenous lactones increase biofilm formation in P. fragi strains. However, all isolates produced furanosyl borate diesters (type II autoinducers; AI-2) when tested using the bioluminescent biosensor strain of Vibrio harveyi (BB170). The production of AI-2 was presumed to be of metabolic origin even though Pseudomonas spp. have not been shown to harbor the luxS gene. Thus, the efficient development of P. fragi in fresh meat is not regulated by an AHL-mediated QS system. The mechanism of AI-2 production and its possible role in spoilage dynamics needs further study.

  6. Non-native acylated homoserine lactones reveal that LuxIR quorum sensing promotes symbiont stability.

    Science.gov (United States)

    Studer, Sarah V; Schwartzman, Julia A; Ho, Jessica S; Geske, Grant D; Blackwell, Helen E; Ruby, Edward G

    2014-08-01

    Quorum sensing, a group behaviour coordinated by a diffusible pheromone signal and a cognate receptor, is typical of bacteria that form symbioses with plants and animals. LuxIR-type N-acyl L-homoserine (AHL) quorum sensing is common in Gram-negative Proteobacteria, and many members of this group have additional quorum-sensing networks. The bioluminescent symbiont Vibrio fischeri encodes two AHL signal synthases: AinS and LuxI. AinS-dependent quorum sensing converges with LuxI-dependent quorum sensing at the LuxR regulatory element. Both AinS- and LuxI-mediated signalling are required for efficient and persistent colonization of the squid host, Euprymna scolopes. The basis of the mutualism is symbiont bioluminescence, which is regulated by both LuxI- and AinS-dependent quorum sensing, and is essential for maintaining a colonization of the host. Here, we used chemical and genetic approaches to probe the dynamics of LuxI- and AinS-mediated regulation of bioluminescence during symbiosis. We demonstrate that both native AHLs and non-native AHL analogues can be used to non-invasively and specifically modulate induction of symbiotic bioluminescence via LuxI-dependent quorum sensing. Our data suggest that the first day of colonization, during which symbiont bioluminescence is induced by LuxIR, is a critical period that determines the stability of the V. fischeri population once symbiosis is established.

  7. Identification of N-acyl homoserine lactones produced by Gluconacetobacter diazotrophicus PAL5 cultured in complex and synthetic media.

    Science.gov (United States)

    Nieto-Peñalver, Carlos G; Bertini, Elisa V; de Figueroa, Lucía I C

    2012-07-01

    The endophytic diazotrophic Gluconacetobacter diazotrophicus PAL5 was originally isolated from sugarcane (Saccharum officinarum). The biological nitrogen fixation, phytohormones secretion, solubilization of mineral nutrients and phytopathogen antagonism allow its classification as a plant growth-promoting bacterium. The recent genomic sequence of PAL5 unveiled the presence of a quorum sensing (QS) system. QS are regulatory mechanisms that, through the production of signal molecules or autoinducers, permit a microbial population the regulation of the physiology in a coordinated manner. The most studied autoinducers in gram-negative bacteria are the N-acyl homoserine lactones (AHLs). The usage of biosensor strains evidenced the presence of AHL-like molecules in cultures of G. diazotrophicus PAL5 grown in complex and synthetic media. Analysis of AHLs performed by LC-APCI-MS permitted the identification of eight different signal molecules, including C6-, C8-, C10-, C12- and C14-HSL. Mass spectra confirmed that this diazotrophic strain also synthesizes autoinducers with carbonyl substitutions in the acyl chain. No differences in the profile of AHLs could be determined under both culture conditions. However, although the level of short-chain AHLs was not affected, a decrease of 30% in the production of long-chain AHLs could be measured in synthetic medium.

  8. Influence of food system conditions on N-acyl-L-homoserine lactones production by Aeromonas spp.

    Science.gov (United States)

    Medina-Martínez, M S; Uyttendaele, M; Demolder, V; Debevere, J

    2006-12-01

    Eleven of 13 Aeromonas strains were shown to produce AHLs. Results of TLC showed that N-butanoyl-L-homoserine lactone (C4-HSL) was the main AHL produced in LB medium at 30 degrees C. The influence of different carbon sources, temperature, pH values and salt concentrations on AHL production was determined in eight A. hydrophila and one A. caviae strain. Additionally a quantitative study of C4-HSL production by A. hydrophila strain 519 under different conditions was performed. Positive results were found in the AHL induction assay for some Aeromonas strains in cultures in LB agar incubated at 12 degrees C after 72-96 h. The induction of the sensor strains by Aeromonas spp. occurred in LB medium supplemented with all carbon sources in a concentration of 0.5%. The production of C4-HSL by A. hydrophila 519 was found until 3.5% (w/v) of NaCl. For pHs close to the neutrality the C4-HSL production by A. hydrophila was evident after 24-48 h of incubation. A. hydrophila 519 produced C4-HSL under anaerobic conditions. Also, the AHL production by Aeromonas strains was studied in simulate agar of shrimp, fish and some vegetables. The production of AHLs was evident by almost all the test strains in shrimp simulated agar. In fish agar only for one of three fish species tested, positive results were found. Induction assay in vegetables simulated agar showed principally negative results, probably because of the presence of inhibitory compounds in these vegetables.

  9. Presence of Acylated Homoserine Lactones (AHLs) and AHL-Producing Bacteria in Meat and Potential Role of AHL in Spoilage of Meat

    OpenAIRE

    Bruhn, Jesper Bartholin; Christensen, Allan Beck; Flodgaard, Lars Ravn; Nielsen, Kristian Fog; Larsen, Thomas Ostenfeld; Givskov, Michael; Gram, Lone

    2004-01-01

    Quorum-sensing (QS) signals (N-acyl homoserine lactones [AHLs]) were extracted and detected from five commercially produced vacuum-packed meat samples. Ninety-six AHL-producing bacteria were isolated, and 92 were identified as Enterobacteriaceae. Hafnia alvei was the most commonly identified AHL-producing bacterium. Thin-layer chromatographic profiles of supernatants from six H. alvei isolates and of extracts from spoiling meat revealed that the major AHL species had an Rf value and shape sim...

  10. A Sinorhizobium meliloti-specific N-acyl homoserine lactone quorum-sensing signal increases nodule numbers in Medicago truncatula independent of autoregulation

    Directory of Open Access Journals (Sweden)

    Debora Fabiola Veliz Vallejos

    2014-10-01

    Full Text Available N-acyl homoserine lactones (AHLs act as quorum sensing signals that regulate cell-density dependent behaviors in many gram-negative bacteria, in particular those important for plant-microbe interactions. AHLs can also be recognized by plants, and this may influence their interactions with bacteria. Here we tested whether the exposure to AHLs affects the nodule-forming symbiosis between legume hosts and rhizobia. We treated roots of the model legume, Medicago truncatula, with a range of AHLs either from its specific symbiont, Sinorhizobium meliloti, or from the potential pathogens, Pseudomonas aeruginosa and Agrobacterium vitis. We found increased numbers of nodules formed on root systems treated with the S. meliloti-specific AHL, 3-oxo-C14-homoserine lactone, at a concentration of 1 μM, while the other AHLs did not result in significant changes to nodule numbers. We did not find any evidence for altered nodule invasion by the rhizobia. Quantification of flavonoids that could act as nod gene inducers in S. meliloti did not show any correlation with increased nodule numbers. The effects of AHLs were specific for an increase in nodule numbers, but not lateral root numbers or root length. Increased nodule numbers following 3-oxo-C14-homoserine lactone treatment were under control of autoregulation of nodulation and were still observed in the autoregulation mutant, sunn4 (super numeric nodules4. However, increases in nodule numbers by 3-oxo-C14-homoserine lactone were not found in the ethylene-insensitive sickle mutant. A comparison between M. truncatula with M. sativa (alfalfa and Trifolium repens (white clover showed that the observed effects of AHLs on nodule numbers were specific to M. truncatula, despite M. sativa nodulating with the same symbiont. We conclude that plant perception of the S. meliloti-specific 3-oxo-C14-homoserine lactone influences nodule numbers in M. truncatula via an ethylene-dependent, but autoregulation

  11. Evidence for existence of quorum sensing in a bioaugmented system by acylated homoserine lactone-dependent quorum quenching.

    Science.gov (United States)

    Zhang, Kun; Zheng, Xin; Shen, Dong-sheng; Wang, Mei-zhen; Feng, Hua-jun; He, Hong-zhen; Wang, Shuo; Wang, Jue-hua

    2015-04-01

    The introduction of a gene, strain, or microbial consortium into an indigenous bacterial population is known as bioaugmentation. This technique has been proposed as an effective strategy for accelerating and enhancing the removal of recalcitrant and toxic compounds during wastewater treatment. In this study, three types of reactors were used to test whether quorum sensing plays an important role in bioaugmented systems. Reverse transcriptase polymerase chain reaction showed that the inoculated strain, HF-1, successfully colonized in the bioaugmented reactor. Meanwhile, no HF-1 colonization was observed in the quorum-quenching and non-bioaugmented reactors. Removal of nicotine in the bioaugmented reactor was almost 100%, and removal of total organic carbon (TOC) was higher than 50%. However, less than 20% of nicotine and 30% of TOC was removed in quorum-quenching and non-bioaugmented reactors. Moreover, the release of acylated homoserine lactones reached the threshold for HF-1 biofilm formation in bioaugmented reactors but not in quorum-quenching or non-bioaugmented reactors. The addition of porcine kidney acylase I, a quenching reagent, to the quorum-quenching reactor hampered the colonization of HF-1. Together, these results demonstrate that quorum sensing plays an important role in HF-1 colonization of bioaugmented systems.

  12. Beneficial effects of bacteria-plant communication based on quorum sensing molecules of the N-acyl homoserine lactone group.

    Science.gov (United States)

    Schikora, Adam; Schenk, Sebastian T; Hartmann, Anton

    2016-04-01

    Bacterial quorum sensing (QS) mechanisms play a crucial role in the proper performance and ecological fitness of bacterial populations. Many key physiological processes are regulated in a QS-dependent manner by auto-inducers, like the N-acyl homoserine lactones (AHLs) in numerous Gram-negative bacteria. In addition, also the interaction between bacteria and eukaryotic hosts can be regulated by AHLs. Those mechanisms gained much attention, because of the positive effects of different AHL molecules on plants. This positive impact ranges from growth promotion to induced resistance and is quite contrasting to the rather negative effects observed in the interactions between bacterial AHL molecules and animals. Only very recently, we began to understand the molecular mechanisms underpinning plant responses to AHL molecules. In this review, we gathered the latest information in this research field. The first part gives an overview of the bacterial aspects of quorum sensing. Later we focus on the impact of AHLs on plant growth and AHL-priming, as one of the most understood phenomena in respect to the inter-kingdom interactions based on AHL-quorum sensing molecules. Finally, we discuss the potential benefits of the understanding of bacteria-plant interaction for the future agricultural applications.

  13. Cell adhesion, ammonia removal and granulation of autotrophic nitrifying sludge facilitated by N-acyl-homoserine lactones.

    Science.gov (United States)

    Li, An-Jie; Hou, Bao-Lian; Li, Mei-Xi

    2015-11-01

    In this study, six N-acyl-homoserine lactone (AHL) molecules (C6-HSL, C8-HSL, C10-HSL, 3-oxo-C6-HSL, 3-oxo-C8-HSL and 3-oxo-C10-HSL) were each dosed into a bioreactor and seeded using autotrophic nitrifying sludge (ANS). The effects of the AHLs on cell adhesion, nitrification and sludge granulation were investigated. The results indicated that the efficiencies of cell adhesion and ammonia removal both had a close correlation with the side chain length and β position substituent group of the AHLs. The best-performing AHL in terms of accelerating bacterial attached-growth was 3-oxo-C6-HSL, whereas C6-HSL outperformed the others in terms of the ammonia degradation rate. The addition of 3-oxo-C6-HSL or C6-HSL increased the biomass growth rate, microbial activity, extracellular proteins and nitrifying bacteria, which can accelerate the formation of nitrifying granules. Consequently, selecting AHL molecules that could improve bacteria in attached-growth mode and nitrification efficiency simultaneously will most likely facilitate the rapid granulation of nitrifying sludge.

  14. Sodium houttuyfonate affects production of N-acyl homoserine lactone and quorum sensing-regulated genes expression in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Daqiang eWu

    2014-11-01

    Full Text Available Quorum sensing (QS is a means of cell-to-cell communication that uses diffusible signaling molecules that are sensed by the population to determine population density, thus allowing co-ordinate gene regulation in response to population density. In Pseudomonas aeruginosa, production of the QS signaling molecule, N-acyl homoserine lactone (AHL, co-ordinates expression of key factors of pathogenesis, including biofilm formation and toxin secretion. It is predicted that the inhibition of AHL sensing would provide an effective clinical treatment to reduce the expression of virulence factors and increase the effectiveness of antimicrobial agents. We previously demonstrated that sodium houttuyfonate (SH, commonly used in traditional Chinese medicine to treat infectious diseases, can effectively inhibit QS-regulated processes, including biofilm formation. Here, using a model system, we demonstrate that SH causes the dose-dependent inhibition of AHL production, through down-regulation of the AHL biosynthesis gene, lasI. Addition of SH also resulted in down-regulation of expression of the AHL sensor and transcriptional regulator, LasR, and inhibited the production of the QS-regulated virulence factors, pyocyanin and LasA. These results suggest that the antimicrobial activity of SH may be due to its ability to disrupt QS in P. aeruginosa.

  15. Hypersensitive response and acyl-homoserine lactone production of the fire blight antagonists Erwinia tasmaniensis and Erwinia billingiae.

    Science.gov (United States)

    Jakovljevic, Vladimir; Jock, Susanne; Du, Zhiqiang; Geider, Klaus

    2008-09-01

    Fire blight caused by the Gram-negative bacterium Erwinia amylovora can be controlled by antagonistic microorganisms. We characterized epiphytic bacteria isolated from healthy apple and pear trees in Australia, named Erwinia tasmaniensis, and the epiphytic bacterium Erwinia billingiae from England for physiological properties, interaction with plants and interference with growth of E. amylovora. They reduced symptom formation by the fire blight pathogen on immature pears and the colonization of apple flowers. In contrast to E. billingiae, E. tasmaniensis strains induced a hypersensitive response in tobacco leaves and synthesized levan in the presence of sucrose. With consensus primers deduced from lsc as well as hrpL, hrcC and hrcR of the hrp region of E. amylovora and of related bacteria, these genes were successfully amplified from E. tasmaniensis DNA and alignment of the encoded proteins to other Erwinia species supported a role for environmental fitness of the epiphytic bacterium. Unlike E. tasmaniensis, the epiphytic bacterium E. billingiae produced an acyl-homoserine lactone for bacterial cell-to-cell communication. Their competition with the growth of E. amylovora may be involved in controlling fire blight.

  16. Profiling of acylated homoserine lactones of Vibrio anguillarum in vitro and in vivo: influence of growth conditions and serotype

    DEFF Research Database (Denmark)

    Buchholtz, Chrstiane; Nielsen, Kristian Fog; L. Milton, Debra

    2006-01-01

    concentration) has little influence on the AHL-profile. Most strains produced N-(3-oxodecanoyl)-l-homoserine lactone (3-oxo-C10-HSL) and N-(3-hydroxy-hexanoyl)-l-homoserine lactone (3-hydroxy-C6-HSL) as the dominant molecules. Also, two spots with AHL activity appeared on TLC plates, which could...... to allow chromatographic detection and separation by both TLC and HLPC-HRMS. 3-oxo-C10-HSL and 3-hydroxy-C6-HSL were detected in organs from fish dying from vibriosis, however, compared to in vitro culturing where 3-oxo-C10-HSL is the dominant molecule, 3-hydroxy-C6-HSL was prominent in the infected fish......-profile. Most strains produced N-(3-oxodecanoyl)-L-homoserine lactone (3-oxo-C10-HSL) and N-(3-hydroxy-hexanoyl)-L-homoserine lactone (3-hydroxy-C6-HSL) as the dominant molecules. Also, two spots with AHL activity appeared on TLC plates, which could not be identified as AHL structures. Trace amounts of N-(3...

  17. N-acyl-L-homoserine lactone-mediated regulation of the Lip secretion system in Serratia liquefaciens MG1

    DEFF Research Database (Denmark)

    Riedel, K.; Ohnesorg, T.; Krogfelt, K.A.

    2001-01-01

    The analysis of Serratia liquefaciens MG1 'luxAB insertion mutants that are responsive to N-butanoyl-L-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing system. LipB is part of the Lip exporter, a type I secretion system, which is responsible...

  18. Characterization and Complete Sequence of Lactonase Enzyme from Bacillus weihenstephanensis Isolate P65 with Potential Activity against Acyl Homoserine Lactone Signal Molecules

    Directory of Open Access Journals (Sweden)

    Masarra Mohammed Sakr

    2013-01-01

    Full Text Available Acyl homoserine lactones (AHLs are the most common class of quorum sensing signal molecules (autoinducers that have been reported to be essential for virulence of many relevant pathogenic bacteria such as Pseudomonas aeruginosa. New approach for controlling infections of such bacteria is through quorum quenching. In this study, the acyl homoserine lactone inhibitory activity of the crude enzyme from a Bacillus weihenstephanensis-isolate P65 was characterized. The crude enzyme was found to have relatively high thermal stability and was stable in pH range 6 to 9. The crude enzyme extract was found to have lactonase activity of 36.3 U/mg total protein. Maximum enzyme activity was achieved within a range of 28–50°C and pH 6–9. None of the metals used enhanced the activity neither did EDTA inhibit it. However, a concentration of 10 mM Fe+2 reduced the activity to 73.8%. Catalytic activity and kinetic constants were determined using hexanoyl homoserine lactone as a substrate. Studying enzyme substrate specificity using synthetic standard signals displayed broad spectrum of activity. The enzyme was found to be constitutive. Isolation and complete nucleotide sequence of the respective lactonase gene were done and submitted to the Genbank database under accession code KC823046.

  19. Presence of acylated homoserine lactones (AHLs) and AHL-producing bacteria in meat and potential role of AHL in spoilage of meat

    DEFF Research Database (Denmark)

    Bruhn, Jesper Bartholin; Christensen, Allan Beck; Flodgaard, Lars

    2004-01-01

    ) analysis confirmed the presence of OHHL in pure cultures of H. alvei. Vacuum-packed meat spoiled at the same rate when inoculated with the H. alvei wild type compared to a corresponding AHL-lacking mutant. Addition of specific QS inhibitors to the AHL-producing H. alvei inoculated in meat or to naturally......Quorum-sensing (QS) signals (N-acyl homoserine lactones [AHLs]) were extracted and detected from five commercially produced vacuum-packed meat samples. Ninety-six AHL-producing bacteria were isolated, and 92 were identified as Enterobacteriaceae. Hafnia alvei was the most commonly identified AHL......-producing bacterium. Thin-layer chromatographic profiles of supernatants from six H. alvei isolates and of extracts from spoiling meat revealed that the major AHL species had an R-f value and shape similar to N-3-oxo-hexanoyl homoserine lactone (OHHL). Liquid chromatography-mass spectrometry (MS) (high-resolution MS...

  20. Fast, Continuous, and High-Throughput (Bio)Chemical Activity Assay for N-Acyl-l-Homoserine Lactone Quorum-Quenching Enzymes

    Science.gov (United States)

    Last, Daniel; Krüger, Georg H. E.; Dörr, Mark

    2016-01-01

    ABSTRACT Quorum sensing, the bacterial cell-cell communication by small molecules, controls important processes such as infection and biofilm formation. Therefore, it is a promising target with several therapeutic and technical applications besides its significant ecological relevance. Enzymes inactivating N-acyl-l-homoserine lactones, the most common class of communication molecules among Gram-negative proteobacteria, mainly belong to the groups of quorum-quenching lactonases or quorum-quenching acylases. However, identification, characterization, and optimization of these valuable biocatalysts are based on a very limited number of fundamentally different methods with their respective strengths and weaknesses. Here, a (bio)chemical activity assay is described, which perfectly complements the other methods in this field. It enables continuous and high-throughput activity measurements of purified and unpurified quorum-quenching enzymes within several minutes. For this, the reaction products released by quorum-quenching lactonases and quorum-quenching acylases are converted either by a secondary enzyme or by autohydrolysis to l-homoserine. In turn, l-homoserine is detected by the previously described calcein assay, which is sensitive to α-amino acids with free N and C termini. Besides its establishment, the method was applied to the characterization of three previously undescribed quorum-quenching lactonases and variants thereof and to the identification of quorum-quenching acylase-expressing Escherichia coli clones in an artificial library. Furthermore, this study indicates that porcine aminoacylase 1 is not active toward N-acyl-l-homoserine lactones as published previously but instead converts the autohydrolysis product N-acyl-l-homoserine. IMPORTANCE In this study, a novel method is presented for the identification, characterization, and optimization of quorum-quenching enzymes that are active toward N-acyl-l-homoserine lactones. These are the most common

  1. Accurate mass analysis of N-acyl-homoserine-lactones and cognate lactone-opened compounds in bacterial isolates of Pseudomonas aeruginosa PAO1 by LC-ESI-LTQ-FTICR-MS.

    Science.gov (United States)

    Cataldi, Tommaso R I; Bianco, Giuliana; Abate, Salvatore

    2009-02-01

    N-acyl-homoserine-lactones (AHSLs) are widely conserved signal molecules present in quorum sensing systems of Gram-negative bacteria such as Pseudomonas aeruginosa. We present here the results obtained with a hybrid linear trap/Fourier transform ion cyclotron resonance (LTQ-FTICR) mass spectrometer used to investigate the occurrence of AHSLs and cognate N-acyl-homoserines (AHSs) in bacterial isolates of P. aeruginosa (strain PAO1). Two hydrolysed AHSs were found in significant amounts, most likely formed through the lactone opening of N-3-oxo-decanoyl-L-homoserine-lactone (3OC10-HSL) and N-3-oxo-dodecanoyl-L-homoserine-lactone (3OC12-HSL). Structure elucidation of these ring-opened molecules, i.e. N-3-oxo-decanoyl-L-homoserine (3OC10-HS), and N-3-oxo-dodecanoyl-L-homoserine (3OC12-HS), which are not detected by bacterial biosensors, was performed by high-resolution and accurate mass measurements upon liquid chromatography (LC) and confirmed by tandem MS in the LTQ analyser. Assignment of chemical formula, with mass spectra in the form of [M+H]+, was significantly expedited by extracted ion chromatograms (XICs) because the number of potentially plausible formulae for each protonated signalling molecule was considerably reduced a priori by the LC behaviour, the high mass measurement accuracy available in FTICR mass spectra and the isotopic patterns. At least two concentration levels were observed in spent culture supernatants of P. aeruginosa: compounds at a relatively high content (5-15 microM) that is C4-HSL, 3OC10-HS, and 3OC12-HS and those occurring at a lower content (<0.2 microM) that is C6-HSL and C8-HSL. The implications of this work extend to a great variety of Gram-negative bacteria.

  2. RNase E affects the expression of the acyl-homoserine lactone synthase gene sinI in Sinorhizobium meliloti.

    Science.gov (United States)

    Baumgardt, Kathrin; Charoenpanich, Pornsri; McIntosh, Matthew; Schikora, Adam; Stein, Elke; Thalmann, Sebastian; Kogel, Karl-Heinz; Klug, Gabriele; Becker, Anke; Evguenieva-Hackenberg, Elena

    2014-04-01

    Quorum sensing of Sinorhizobium meliloti relies on N-acyl-homoserine lactones (AHLs) as autoinducers. AHL production increases at high population density, and this depends on the AHL synthase SinI and two transcriptional regulators, SinR and ExpR. Our study demonstrates that ectopic expression of the gene rne, coding for RNase E, an endoribonuclease that is probably essential for growth, prevents the accumulation of AHLs at detectable levels. The ectopic rne expression led to a higher level of rne mRNA and a lower level of sinI mRNA independently of the presence of ExpR, the AHL receptor, and AHLs. In line with this, IPTG (isopropyl-β-D-thiogalactopyranoside)-induced overexpression of rne resulted in a shorter half-life of sinI mRNA and a strong reduction of AHL accumulation. Moreover, using translational sinI-egfp fusions, we found that sinI expression is specifically decreased upon induced overexpression of rne, independently of the presence of the global posttranscriptional regulator Hfq. The 28-nucleotide 5' untranslated region (UTR) of sinI mRNA was sufficient for this effect. Random amplification of 5' cDNA ends (5'-RACE) analyses revealed a potential RNase E cleavage site at position +24 between the Shine-Dalgarno site and the translation start site. We postulate therefore that RNase E-dependent degradation of sinI mRNA from the 5' end is one of the steps mediating a high turnover of sinI mRNA, which allows the Sin quorum-sensing system to respond rapidly to changes in transcriptional control of AHL production.

  3. N-acyl-L-homoserine lactone-mediated regulation of the Lip secretion system in Serratia liquefaciens MG1

    DEFF Research Database (Denmark)

    Riedel, K.; Ohnesorg, T.; Krogfelt, K.A.

    2001-01-01

    The analysis of Serratia liquefaciens MG1 'luxAB insertion mutants that are responsive to N-butanoyl-L-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing system. LipB is part of the Lip exporter, a type I secretion system, which is responsible for the secr......The analysis of Serratia liquefaciens MG1 'luxAB insertion mutants that are responsive to N-butanoyl-L-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing system. LipB is part of the Lip exporter, a type I secretion system, which is responsible...

  4. Iron limitation enhances acyl homoserine lactone (AHL) production and biofilm formation in clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Modarresi, Farzan; Azizi, Omid; Shakibaie, Mohammad Reza; Motamedifar, Mohammad; Mosadegh, Ellahe; Mansouri, Shahla

    2015-01-01

    Acinetobacter baumannii is an important source of infections in intensive care units (ICUs) of our hospitals in Kerman, Iran and the most frequently isolated strains produce biofilm. There is a little information about role of iron (Fe) levels on acyl homoserine lactone (AHL) production and biofilm formation in this microorganism. In the present study, we investigated the influence of iron-III limitation on AHL, siderophore, catechol and virulence factors in the biofilm forming clinical strains of A. baumannii. A total of 65 non-duplicated multidrug resistance (MDR) strains of A. baumannii were isolated from patients in ICUs of 2 hospitals in Kerman, Iran. Antibiotic susceptibility, siderophore and other iron chelators, hemolysis, cell twitching motility, capsule, gelatinase and DNase were studied. Presence of quorum sensing, LuxI and LuxR genes was detected by multiplex-PCR. AHL activity quantified by colorimetric method and the functional groups were determined by Fourier Transform Infra-Red Spectroscopy (FT-IR). Biofilm formation was detected by microtiter plate technique. All of the isolates were resistant to third generation of cephalosporins, ciprofloxacin, levofloxacin, tetracycline, whereas, 78% and 81% were resistant to amikacin and carbapenems, respectively. The siderophore activity was highest at 20 μM Fe(3+) (70%); however, it decreased to 45% as concentration of Fe(3+) increased to 80 μM. Furthermore, screening of the isolates for LuxI and LuxR genes showed that presence of both genes required in the isolates with high AHL activity. FT-IR analysis indicated C=O bond of the lactone ring and primary amides. Significantly, a higher amount of AHL (70%) was detected in the presence of low concentration of iron-III (20 μM); as iron concentration increased to 80 μM, the AHL activity was reduced to 40% (P ≤ 0.05). All the isolates exhibited twitching motility and had a capsule. No any gelatinase or DNase activity was detected. Quantification of the

  5. Deuterium-labelled N-acyl-l-homoserine lactones (AHLs) - inter-kingdom signalling molecules - synthesis, structural studies, and interactions with model lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Jakubczyk, Dorota [Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Barth, Christoph; Anastassacos, Frances; Koelsch, Patrick; Schepers, Ute [Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Kubas, Adam; Fink, Karin [Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Brenner-Weiss, Gerald [Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Braese, Stefan [Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2012-04-15

    N-Acyl-l-homoserine lactones (AHLs) are synthesized by Gram-negative bacteria. These quorum-sensing molecules play an important role in the context of bacterial infection and biofilm formation. They also allow communication between microorganisms and eukaryotic cells (inter-kingdom signalling). However, very little is known about the entire mechanism of those interactions. Precise structural studies are required to analyse the different AHL isomers as only one form is biologically most active. Theoretical studies combined with experimental infrared and Raman spectroscopic data are therefore undertaken to characterise the obtained compounds. To mimic interactions between AHL and cell membranes, we studied the insertion of AHL in supported lipid bilayers, using vibrational sum-frequency-generation spectroscopy. Deuterium-labelled AHLs were thus synthesized. Starting from readily available deuterated fatty acids, a two-step procedure towards deuterated N-acyl-l-homoserine lactones with varying chain lengths is described. This included the acylation of Meldrum's acid followed by amidation. Additionally, the detailed analytical evaluation of the products is presented herein. (orig.)

  6. Inhibition of Lux quorum-sensing system by synthetic N-acyl-L-homoserine lactone analogous.

    Science.gov (United States)

    Wang, Wenzhao; Morohoshi, Tomohiro; Ikeda, Tsukasa; Chen, Liang

    2008-12-01

    In the present study, we investigated the inhibition of the Lux quorum-sensing system by N-acyl cyclopentylamine (Cn-CPA). The Lux quorum-sensing system regulates luminescence gene expression in Vibrio fischeri. We have already reported on the synthesis of Cn-CPA and their abilities as inhibitors of the quorum-sensing systems in Pseudomonas aeruginosa and Serratia marcescens. In the case of Pseudomonas aeruginosa (Las and Rhl quorum-sensing system) and Serratia marcescens (Spn quorum-sensing system), specific Cn-CPA with a particular acyl chain length showed the strongest inhibitory effect. In the case of the Lux quorum-sensing system, it was found that several kinds of Cn-CPA with a range from C5 to C10 showed similar strong inhibitory effects. Moreover, the inhibitory effect of Cn-CPA on the Lux quorum-sensing system was stronger than that of halogenated furanone, a natural quorum-sensing inhibitor.

  7. Rational design and synthesis of new quorum-sensing inhibitors derived from acylated homoserine lactones and natural products from garlic

    DEFF Research Database (Denmark)

    Persson, T.; Rasmussen, Thomas Bovbjerg; Skindersoe, M.

    2005-01-01

    with similarity both to sulfides 10a-s and to bioactive structures from garlic. Design and biological screening of all compounds presented in this work targeted inhibition of quorum-sensing comprising competitive inhibition of transcriptional regulators LuxR and LasR. The design was based on critical interactions...... within the binding-site and structural motifs in molecular components isolated from garlic, 7 and 8, shown to be quorum-sensing inhibitors but not antibiotics. A potent quorum-sensing inhibitor N-(heptylsulfanylacetyl)-L-homoserine lactone (10c) was identified. Together with data collected for the other...

  8. Exploring the active site of acyl homoserine lactones-dependent transcriptional regulators with bacterial quorum sensing modulators using molecular mechanics and docking studies.

    Science.gov (United States)

    Soulère, Laurent; Frezza, Marine; Queneau, Yves; Doutheau, Alain

    2007-09-01

    A comparative molecular modelling study of acyl homoserine lactones-dependent transcriptional regulators (TraR, SdiA, LuxR and LasR) involved in bacterial quorum sensing (QS) revealed a high structural homology of their active site. Docking studies within the active site of TraR of fixed conformations obtained using molecular mechanics calculations showed that TraR, for which the crystalline structure is known, is a relevant model for the study of other protein-ligand interactions in the same protein family. Structure-activity relationships of AHLs derived QS modulators including carboxamides, sulfonamides and ureas were thus investigated. The results show that Tyr61, a residue conserved in the LuxR-proteins family, is involved in attractive interactions with aromatic carboxamide antagonists. Tyr53, Tyr61 and Asp70, conserved residues, are implicated in both the development of additional hydrogen bonds and attractive interactions with the N-sulfonyl homoserine lactones and AHLs derived ureas antagonists.

  9. The acyl-homoserine lactone-type quorum-sensing system modulates cell motility and virulence of Erwinia chrysanthemi pv. zeae.

    Science.gov (United States)

    Hussain, Mumtaz B B M; Zhang, Hai-Bao; Xu, Jin-Ling; Liu, Qiongguang; Jiang, Zide; Zhang, Lian-Hui

    2008-02-01

    Erwinia chrysanthemi pv. zeae is one of the Erwinia chrysanthemi pathovars that infects on both dicotyledons and monocotyledons. However, little is known about the molecular basis and regulatory mechanisms of its virulence. By using a transposon mutagenesis approach, we cloned the genes coding for an E. chrysanthemi pv. zeae synthase of acyl-homoserine lactone (AHL) quorum-sensing signals (expI(Ecz)) and a cognate response regulator (expR(Ecz)). Chromatography analysis showed that expI(Ecz) encoded production of the AHL signal N-(3-oxo-hexanoyl)-homoserine lactone (OHHL). Null mutation of expI(Ecz) in the E. chrysanthemi pv. zeae strain EC1 abolished AHL production, increased bacterial swimming and swarming motility, disabled formation of multicell aggregates, and attenuated virulence of the pathogen on potato tubers. The mutation also marginally reduced the inhibitory activity of E. chrysanthemi pv. zeae on rice seed germination. The mutant phenotypes were rescued by either exogenous addition of AHL signal or in trans expression of expI(Ecz). These data demonstrate that the AHL-type QS signal plays an essential role in modulation of E. chrysanthemi pv. zeae cell motility and the ability to form multicell aggregates and is involved in regulation of bacterial virulence.

  10. Development of an extraction method and LC-MS analysis for N-acylated-l-homoserine lactones (AHLs) in wastewater treatment biofilms.

    Science.gov (United States)

    Wang, Jinfeng; Ding, Lili; Li, Kan; Schmieder, Wilhelm; Geng, Jinju; Xu, Ke; Zhang, Yan; Ren, Hongqiang

    2017-01-15

    N-Acylated-l-homoserine lactones (AHLs) play a vital role in Gram-negative bacteria communication by promoting the formation of extracellular polymeric substances (EPS) and biofilms. However, the low concentration of these AHL signals makes the process difficult to understand. A robust and sensitive pretreatment method for AHL detection was developed in this work. Compared with eight different solid-phase extraction (SPE) columns and three various solid extraction method, we found that the UE (ultrasonic extraction) and an Oasis hydrophilic-lipophilic-balanced (HLB) sorbent in column format combined with ultra-performance liquid chromatography linked to tandem mass spectrometry (UPLC-MS/MS) can be successfully used for systematic pretreating moving bed biofilm reactor (MBBR) biological samples to extract AHLs and determine concentration of AHLs in wastewater treatment biofilms. This easy-to-follow protocol makes it ideal for quantitative analyses of AHLs in wastewater treatment biofilms.

  11. Novel acridine-based N-acyl-homoserine lactone analogs induce endoreduplication in the human oral squamous carcinoma cell line SAS.

    Science.gov (United States)

    Chai, Hongbo; Hazawa, Masaharu; Hosokawa, Yoichiro; Igarashi, Jun; Suga, Hiroaki; Kashiwakura, Ikuo

    2012-01-01

    The cytotoxicity of novel acridine-based N-acyl-homoserine lactone (AHL) analogs was investigated on the human oral squamous carcinoma cell line SAS. One analog induced G2/M phase arrest at 5.3-10.6 µM and induced polyploidy at a higher dose (21.2 µM). Importantly, treatment of SAS cells with a combination of the AHL analog and the Jun N-terminal kinase (JNK) inhibitor, SP600125, prevented mitosis and induced polyploidy. The AHL analog synergized with X-irradiation to inhibit clonogenic survival of SAS cells; however, its radiosensitizing effects were relative to not X-irradiation-induced apoptosis but mitotic failure following enhanced expression of Aurora A and B. These results suggest that the active AHL analog showed growth-suppressive and radiosensitizing effects, which involve polyploidy followed by G2/M accumulation and atypical cell death in the SAS cell line.

  12. Production of acylated homoserine lactones by different serotypes of Vibrio anguillarum both in culture and during infection of rainbow trout

    DEFF Research Database (Denmark)

    Buch, Christiane; Sigh, Jens; Nielsen, John;

    2003-01-01

    strain, a serotype O4, induced a strong response in the Chromobacterium violaceum (CV026) monitoring system. Profiles of AHLs determined by TLC separation revealed the presence of at least four AHLs and a compound similar to N-3-oxo-decanoyl homoserine lactone (3-oxo-C10-HSL) was present in all strains....... The production rate of the presumed 3-oxo-C10-HSL followed the growth rate of V. anguillarum whereas the production rate of a small AHL (Rf value of 0.74) increased faster than the growth rate of V. anguillarum indicating autoinduction. AHLs were produced by all serotypes (O1 to O10) and by non-typable strains...... determining oxidative burst of fish macrophages exposed to 3-oxo-C10-HSL. No activation or suppression of the superoxide anion production in the head kidney macrophages was seen when treated with the AHL compound in concentrations of 1 nM-10 μM. Our data show that AHLs are produced by almost all V...

  13. LuxR- and acyl-homoserine-lactone-controlled non-lux genes define a quorum-sensing regulon in Vibrio fischeri.

    Science.gov (United States)

    Callahan, S M; Dunlap, P V

    2000-05-01

    The luminescence (lux) operon (luxICDABEG) of the symbiotic bacterium Vibrio fischeri is regulated by the transcriptional activator LuxR and two acyl-homoserine lactone (acyl-HSL) autoinducers (the luxI-dependent 3-oxo-hexanoyl-HSL [3-oxo-C6-HSL] and the ainS-dependent octanoyl-HSL [C8-HSL]) in a population density-responsive manner called quorum sensing. To identify quorum-sensing-regulated (QSR) proteins different from those encoded by lux genes, we examined the protein patterns of V. fischeri quorum-sensing mutants defective in luxI, ainS, and luxR by two-dimensional polyacrylamide gel electrophoresis. Five non-Lux QSR proteins, QsrP, RibB, AcfA, QsrV, and QSR 7, were identified; their production occurred preferentially at high population density, required both LuxR and 3-oxo-C6-HSL, and was inhibited by C8-HSL at low population density. The genes encoding two of the QSR proteins were characterized: qsrP directs cells to synthesize an apparently novel periplasmic protein, and ribB is a homolog of the Escherichia coli gene for 3,4-dihydroxy-2-butanone 4-phosphate synthase, a key enzyme for riboflavin synthesis. The qsrP and ribB promoter regions each contained a sequence similar to the lux operon lux box, a 20-bp region of dyad symmetry necessary for LuxR/3-oxo-C6-HSL-dependent activation of lux operon transcription. V. fischeri qsrP and ribB mutants exhibited no distinct phenotype in culture. However, a qsrP mutant, in competition with its parent strain, was less successful in colonizing Euprymna scolopes, the symbiotic host of V. fischeri. The newly identified QSR genes, together with the lux operon, define a LuxR/acyl-HSL-responsive quorum-sensing regulon in V. fischeri.

  14. The Effect of Conformational Variability of Phosphotriesterase upon N-acyl-L-homoserine Lactone and Paraoxon Binding: Insights from Molecular Dynamics Studies

    Directory of Open Access Journals (Sweden)

    Dongling Zhan

    2013-12-01

    Full Text Available The organophosphorous hydrolase (PTE from Brevundimonas diminuta is capable of degrading extremely toxic organophosphorous compounds with a high catalytic turnover and broad substrate specificity. Although the natural substrate for PTE is unknown, its loop remodeling (loop 7-2/H254R led to the emergence of a homoserine lactonase (HSL activity that is undetectable in PTE (kcat/km values of up to 2 × 104, with only a minor decrease in PTE paraoxonase activity. In this study, homology modeling and molecular dynamics simulations have been undertaken seeking to explain the reason for the substrate specificity for the wild-type and the loop 7-2/H254R variant. The cavity volume estimated results showed that the active pocket of the variant was almost two fold larger than that of the wild-type (WT enzyme. pKa calculations for the enzyme (the WT and the variant showed a significant pKa shift from WT standard values (ΔpKa = 3.5 units for the His254residue (in the Arg254 variant. Molecular dynamics simulations indicated that the displacement of loops 6 and 7 over the active site in loop 7-2/H254R variant is useful for N-acyl-L-homoserine lactone (C4-HSL with a large aliphatic chain to site in the channels easily. Thence the expanding of the active pocket is beneficial to C4-HSL binding and has a little effect on paraoxon binding. Our results provide a new theoretical contribution of loop remodeling to the rapid divergence of new enzyme functions.

  15. Acyl-homoserine lactone-based quorum sensing and quorum quenching hold promise to determine the performance of biological wastewater treatments: An overview.

    Science.gov (United States)

    Huang, Jinhui; Shi, Yahui; Zeng, Guangming; Gu, Yanling; Chen, Guiqiu; Shi, Lixiu; Hu, Yi; Tang, Bi; Zhou, Jianxin

    2016-08-01

    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.

  16. N-Acyl Homoserine Lactone-Mediated Quorum Sensing with Special Reference to Use of Quorum Quenching Bacteria in Membrane Biofouling Control

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    Harshad Lade

    2014-01-01

    Full Text Available Membrane biofouling remains a severe problem to be addressed in wastewater treatment systems affecting reactor performance and economy. The finding that many wastewater bacteria rely on N-acyl homoserine lactone-mediated quorum sensing to synchronize their activities essential for biofilm formations; the quenching bacterial quorum sensing suggests a promising approach for control of membrane biofouling. A variety of quorum quenching compounds of both synthetic and natural origin have been identified and found effective in inhibition of membrane biofouling with much less environmental impact than traditional antimicrobials. Work over the past few years has demonstrated that enzymatic quorum quenching mechanisms are widely conserved in several prokaryotic organisms and can be utilized as a potent tool for inhibition of membrane biofouling. Such naturally occurring bacterial quorum quenching mechanisms also play important roles in microbe-microbe interactions and have been used to develop sustainable nonantibiotic antifouling strategies. Advances in membrane fabrication and bacteria entrapment techniques have allowed the implication of such quorum quenching bacteria for better design of membrane bioreactor with improved antibiofouling efficacies. In view of this, the present paper is designed to review and discuss the recent developments in control of membrane biofouling with special emphasis on quorum quenching bacteria that are applied in membrane bioreactors.

  17. Detection and characterization of N-acyl-l-homoserine lactones using GFP-based biosensors in conjunction with thin-layer chromatography.

    Science.gov (United States)

    Charlesworth, James; Kimyon, Onder; Manefield, Michael; Burns, Brendan P

    2015-11-01

    Many microorganisms use quorum sensing to regulate several complex phenotypes, and this is accomplished by the release of a signal molecule(s) into the environment. N-acyl-homoserine lactones (AHLs) are a common class of signalling molecule utilized by a range of microorganisms (primarily Gram negative bacteria but most recently also archaea) and are often detected through the use of bacterial biosensors. Biosensors can be limited by both their specificity and sensitivity, and the aim of this study was to modify and improve current AHL detection strategies. The biosensor employed in the present study was Escherichia coli MT102 harbouring a plasmid containing a LuxR based biosensor, which produces green fluorescent protein (GFP) as a reporting mechanism. A new method of visualizing the GFP based biosensor overlaid on silica sheets for the purpose of thin-layer chromatography (TLC) is presented. This new method vastly improves sensitivity of AHL detection by a GFP biosensor than previously reported and as such represents a powerful new tool in AHL research. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. N-acyl homoserine lactone-mediated quorum sensing with special reference to use of quorum quenching bacteria in membrane biofouling control.

    Science.gov (United States)

    Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

    2014-01-01

    Membrane biofouling remains a severe problem to be addressed in wastewater treatment systems affecting reactor performance and economy. The finding that many wastewater bacteria rely on N-acyl homoserine lactone-mediated quorum sensing to synchronize their activities essential for biofilm formations; the quenching bacterial quorum sensing suggests a promising approach for control of membrane biofouling. A variety of quorum quenching compounds of both synthetic and natural origin have been identified and found effective in inhibition of membrane biofouling with much less environmental impact than traditional antimicrobials. Work over the past few years has demonstrated that enzymatic quorum quenching mechanisms are widely conserved in several prokaryotic organisms and can be utilized as a potent tool for inhibition of membrane biofouling. Such naturally occurring bacterial quorum quenching mechanisms also play important roles in microbe-microbe interactions and have been used to develop sustainable nonantibiotic antifouling strategies. Advances in membrane fabrication and bacteria entrapment techniques have allowed the implication of such quorum quenching bacteria for better design of membrane bioreactor with improved antibiofouling efficacies. In view of this, the present paper is designed to review and discuss the recent developments in control of membrane biofouling with special emphasis on quorum quenching bacteria that are applied in membrane bioreactors.

  19. Antipathogenic potential of marine Bacillus sp. SS4 on N-acyl-homoserine-lactone-mediated virulence factors production in Pseudomonas aeruginosa (PAO1)

    Indian Academy of Sciences (India)

    K Syed Musthafa; V Saroja; S Karutha Pandian; A Veera Ravi

    2011-03-01

    Antipathogenic therapy is an outcome of the quorum-sensing inhibition (QSI) mechanism, which targets autoinducer-dependent virulent gene expression in bacterial pathogens. -acyl homoserine lactone (AHL) acts as a key regulator in the production of virulence factors and biofilm formation in Pseudomonas aeruginosa PAO1 and violacein pigment production in Chromobacterium violaceum. In the present study, the marine bacterial strain SS4 showed potential QSI activity in a concentration-dependent manner (0.5–2 mg/ml) against the AHL-mediated violacein production in C. violaceum (33–86%) and biofilm formation (33–88%), total protease (20–65%), LasA protease (59–68%), LasB elastase (36–68%), pyocyanin (17–86%) and pyoverdin productions in PAO1. The light and confocal laser scanning microscopic analyses confirmed the reduction of the biofilm-forming ability of PAO1 when treated with SS4 extract. Furthermore, the antibiofilm potential was confirmed through static biofilm ring assay, in which ethyl acetate extract of SS4 showed concentration-dependent reduction in the biofilm-forming ability of PAO1. Thus, the result of this study clearly reveals the antipathogenic and antibiofilm properties of the bacterial isolate SS4. Through 16S rDNA analysis, the strain SS4 was identified as Bacillus sp. (GenBank Accession Number: GU471751).

  20. Presence of acylated homoserine lactones (AHLs) and AHL-producing bacteria in meat and potential role of AHL in spoilage of meat.

    Science.gov (United States)

    Bruhn, Jesper Bartholin; Christensen, Allan Beck; Flodgaard, Lars Ravn; Nielsen, Kristian Fog; Larsen, Thomas Ostenfeld; Givskov, Michael; Gram, Lone

    2004-07-01

    Quorum-sensing (QS) signals (N-acyl homoserine lactones [AHLs]) were extracted and detected from five commercially produced vacuum-packed meat samples. Ninety-six AHL-producing bacteria were isolated, and 92 were identified as Enterobacteriaceae. Hafnia alvei was the most commonly identified AHL-producing bacterium. Thin-layer chromatographic profiles of supernatants from six H. alvei isolates and of extracts from spoiling meat revealed that the major AHL species had an R(f) value and shape similar to N-3-oxo-hexanoyl homoserine lactone (OHHL). Liquid chromatography-mass spectrometry (MS) (high-resolution MS) analysis confirmed the presence of OHHL in pure cultures of H. alvei. Vacuum-packed meat spoiled at the same rate when inoculated with the H. alvei wild type compared to a corresponding AHL-lacking mutant. Addition of specific QS inhibitors to the AHL-producing H. alvei inoculated in meat or to naturally contaminated meat did not influence the spoilage of vacuum-packed meat. An extracellular protein of approximately 20 kDa produced by the H. alvei wild-type was not produced by the AHL-negative mutant but was restored in the mutant when complemented by OHHL, thus indicating that AHLs do have a regulatory role in H. alvei. Coinoculation of H. alvei wild-type with an AHL-deficient Serratia proteamaculans B5a, in which protease secretion is QS regulated, caused spoilage of liquid milk. By contrast, coinoculation of AHL-negative strains of H. alvei and S. proteamaculans B5a did not cause spoilage. In conclusion, AHL and AHL-producing bacteria are present in vacuum-packed meat during storage and spoilage, but AHL does not appear to influence the spoilage of this particular type of conserved meat. Our data indicate that AHL-producing H. alvei may induce food quality-relevant phenotypes in other bacterial species in the same environment. H. alvei may thus influence spoilage of food products in which Enterobacteriaceae participate in the spoilage process.

  1. Interplay between 4-Hydroxy-3-Methyl-2-Alkylquinoline and N-Acyl-Homoserine Lactone Signaling in a Burkholderia cepacia Complex Clinical Strain

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    Annelise Chapalain

    2017-06-01

    Full Text Available Species from the Burkholderia cepacia complex (Bcc share a canonical LuxI/LuxR quorum sensing (QS regulation system named CepI/CepR, which mainly relies on the acyl-homoserine lactone (AHL, octanoyl-homoserine lactone (C8-HSL as signaling molecule. Burkholderia ambifaria is one of the least virulent Bcc species, more often isolated from rhizospheres where it exerts a plant growth-promoting activity. However, clinical strains of B. ambifaria display distinct features, such as phase variation and higher virulence properties. Notably, we previously reported that under laboratory conditions, only clinical strains of the B. ambifaria species produced 4-hydroxy-3-methyl-2-alkylquinolines (HMAQs via expression of the hmqABCDEFG operon. HMAQs are the methylated counterparts of the 4-hydroxy-2-alkylquinolines (HAQs produced by the opportunistic human pathogen Pseudomonas aeruginosa, in which they globally contribute to the bacterial virulence and survival. We have found that unlike P. aeruginosa’s HAQs, HMAQs do not induce their own production. However, they indirectly regulate the expression of the hmqABCDEFG operon. In B. ambifaria, a strong link between CepI/CepR-based QS and HMAQs is proposed, as we have previously reported an increased production of C8-HSL in HMAQ-negative mutants. Here, we report the identification of all AHLs produced by the clinical B. ambifaria strain HSJ1, namely C6-HSL, C8-HSL, C10-HSL, 3OHC8-HSL, 3OHC10-HSL, and 3OHC12-HSL. Production of significant levels of hydroxylated AHLs prompted the identification of a second complete LuxI/LuxR-type QS system relying on 3OHC10-HSL and 3OHC12-HSL, that we have named CepI2/CepR2. The connection between these two QS systems and the hmqABCDEFG operon, responsible for HMAQs biosynthesis, was investigated. The CepI/CepR system strongly induced the operon, while the second system appears moderately involved. On the other hand, a HMAQ-negative mutant overproduces AHLs from both QS systems

  2. Insights into the Quorum Sensing Regulon of the Acidophilic Acidithiobacillus ferrooxidans Revealed by Transcriptomic in the Presence of an Acyl Homoserine Lactone Superagonist Analog.

    Science.gov (United States)

    Mamani, Sigde; Moinier, Danielle; Denis, Yann; Soulère, Laurent; Queneau, Yves; Talla, Emmanuel; Bonnefoy, Violaine; Guiliani, Nicolas

    2016-01-01

    While a functional quorum sensing system has been identified in the acidophilic chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 23270(T) and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in A. ferrooxidans (T), the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic superagonist AHL (N-acyl homoserine lactones) analog has been studied. First, the effect on biofilm formation of a synthetic AHL tetrazolic analog, tetrazole 9c, known for its agonistic QS activity, was assessed by fluorescence and electron microscopy. A fast adherence of A. ferrooxidans (T) cells on sulfur coupons was observed. Then, tetrazole 9c was used in DNA microarray experiments that allowed the identification of genes regulated by quorum sensing signaling, and more particularly, those involved in early biofilm formation. Interestingly, afeI gene, encoding the AHL synthase, but not the A. ferrooxidans quorum sensing transcriptional regulator AfeR encoding gene, was shown to be regulated by quorum sensing. Data indicated that quorum sensing network represents at least 4.5% (141 genes) of the ATCC 23270(T) genome of which 42.5% (60 genes) are related to biofilm formation. Finally, AfeR was shown to bind specifically to the regulatory region of the afeI gene at the level of the palindromic sequence predicted to be the AfeR binding site. Our results give new insights on the response of A. ferrooxidans to quorum sensing and on biofilm biogenesis.

  3. PpoR is a conserved unpaired LuxR solo of Pseudomonas putida which binds N-acyl homoserine lactones

    Directory of Open Access Journals (Sweden)

    Venturi Vittorio

    2009-06-01

    Full Text Available Abstract Background Only a small number of Pseudomonas putida strains possess the typical N-acyl homoserine lactone quorum sensing system (AHL QS that consists of a modular LuxR family protein and its cognate LuxI homolog that produces the AHL signal. Moreover, AHL QS systems in P. putida strains are diverse in the type of AHLs they produce and the phenotypes that they regulate. Results We identified an unpaired LuxR solo (QS luxR homolog that occurs without the corresponding luxI homolog, which is highly conserved in both the AHL producing and non-AHL producing P. putida strains that we analyzed. In this study we report the cloning and functional characterization of this unpaired LuxR homolog designated PpoR. An AHL binding assay showed that PpoR protein binds to 3-oxo-C6-HSL. Studies using a ppoR promoter-lacZ reporter fusion revealed that it exhibits stringent growth phase dependent expression. Functional interaction of PpoR with the endogenous complete AHL QS systems of P. putida WCS358 (PpuI/R system and PpoR was also investigated. Microarray analysis of P. putida WCS358 wild type and a PpoR over-expressing strain revealed several putative target genes that may be directly or indirectly regulated by PpoR. Conclusion Our results indicate that PpoR in P. putida strains may have a conserved role in detecting an AHL signal, either self or foreign, and regulating specific target genes.

  4. Genome sequencing-assisted identification and the first functional validation of N-acyl-homoserine-lactone synthases from the Sphingomonadaceae family

    Directory of Open Access Journals (Sweden)

    Han Ming Gan

    2016-08-01

    Full Text Available Background Members of the genus Novosphingobium have been isolated from a variety of environmental niches. Although genomics analyses have suggested the presence of genes associated with quorum sensing signal production e.g., the N-acyl-homoserine lactone (AHL synthase (luxI homologs in various Novosphingobium species, to date, no luxI homologs have been experimentally validated. Methods In this study, we report the draft genome of the N-(AHL-producing bacterium Novosphingobium subterraneum DSM 12447 and validate the functions of predicted luxI homologs from the bacterium through inducible heterologous expression in Agrobacterium tumefaciens strain NTL4. We developed a two-dimensional thin layer chromatography bioassay and used LC-ESI MS/MS analyses to separate, detect and identify the AHL signals produced by the N. subterraneum DSM 12447 strain. Results Three predicted luxI homologs were annotated to the locus tags NJ75_2841 (NovINsub1, NJ75_2498 (NovINsub2, and NJ75_4146 (NovINsub3. Inducible heterologous expression of each luxI homologs followed by LC-ESI MS/MS and two-dimensional reverse phase thin layer chromatography bioassays followed by bioluminescent ccd camera imaging indicate that the three LuxI homologs are able to produce a variety of medium-length AHL compounds. New insights into the LuxI phylogeny was also gleemed as inferred by Bayesian inference. Discussion This study significantly adds to our current understanding of quorum sensing in the genus Novosphingobium and provide the framework for future characterization of the phylogenetically interesting LuxI homologs from members of the genus Novosphingobium and more generally the family Sphingomonadaceae.

  5. Quorum Sensing N-acyl Homoserine Lactones-SdiA Suppresses Escherichia coli-Pseudomonas aeruginosa Conjugation through Inhibiting traI Expression

    Science.gov (United States)

    Lu, Yang; Zeng, Jianming; Wu, Binning; E, Shunmei; Wang, Lina; Cai, Renxin; Zhang, Ni; Li, Youqiang; Huang, Xianzhang; Huang, Bin; Chen, Cha

    2017-01-01

    Conjugation is a key mechanism for horizontal gene transfer and plays an important role in bacterial evolution, especially with respect to antibiotic resistance. However, little is known about the role of donor and recipient cells in regulation of conjugation. Here, using an Escherichia coli (SM10λπ)-Pseudomonas aeruginosa (PAO1) conjugation model, we demonstrated that deficiency of lasI/rhlI, genes associated with generation of the quorum sensing signals N-acyl homoserine lactones (AHLs) in PAO1, or deletion of the AHLs receptor SdiA in the donor SM10λπ both facilitated conjugation. When using another AHLs-non-producing E. coli strain EC600 as recipient cells, deficiency of sdiA in donor SM10λπ hardly affect the conjugation. More importantly, in the presence of exogenous AHLs, the conjugation efficiency between SM10λπ and EC600 was dramatically decreased, while deficiency of sdiA in SM10λπ attenuated AHLs-inhibited conjugation. These data suggest the conjugation suppression function of AHLs-SdiA chemical signaling. Further bioinformatics analysis, β-galactosidase reporter system and electrophoretic mobility shift assays characterized the binding site of SdiA on the promoter region of traI gene. Furthermore, deletion of lasI/rhlI or sdiA promoted traI mRNA expression in SM10λπ and PAO1 co-culture system, which was abrogated by AHLs. Collectively, our results provide new insight into an important contribution of quorum sensing system AHLs-SdiA to the networks that regulate conjugation. PMID:28164039

  6. Draft Genome Perspective of Staphylococcus saprophyticus Strain SU8, an N-Acyl Homoserine Lactone-Degrading Bacterium.

    Science.gov (United States)

    Chan, Kok-Gan; Sulaiman, Joanita; Yong, Delicia Ann; Tee, Kok Keng; Yin, Wai-Fong; Priya, Kumutha

    2015-09-24

    Staphylococcus saprophyticus strain SU8 was isolated from a pristine water source in Malaysia and it exhibited degradation of N-hexanoylhomoserine lactone. Here we report the draft genome sequence of S. saprophyticus strain SU8 to further understand its quorum quenching abilities.

  7. N-acyl Homoserine Lactone-Producing Pseudomonas putida Strain T2-2 from Human Tongue Surface

    Directory of Open Access Journals (Sweden)

    Yeun Mun Choo

    2013-09-01

    Full Text Available Bacterial cell-to-cell communication (quorum sensing refers to the regulation of bacterial gene expression in response to changes in microbial population density. Quorum sensing bacteria produce, release and respond to chemical signal molecules called autoinducers. Bacteria use two types of autoinducers, namely autoinducer-1 (AI-1 and autoinducer-2 (AI-2 where the former are N-acylhomoserine lactones and the latter is a product of the luxS gene. Most of the reported literatures show that the majority of oral bacteria use AI-2 for quorum sensing but rarely the AI-1 system. Here we report the isolation of Pseudomonas putida strain T2-2 from the oral cavity. Using high resolution mass spectrometry, it is shown that this isolate produced N-octanoylhomoserine lactone (C8-HSL and N-dodecanoylhomoserine lactone (C12-HSL molecules. This is the first report of the finding of quorum sensing of P. putida strain T2-2 isolated from the human tongue surface and their quorum sensing molecules were identified.

  8. Characterization of N-acyl homoserine lactones (AHLs) producing bacteria isolated from vacuum-packaged refrigerated turbot (Scophthalmus maximus) and possible influence of exogenous AHLs on bacterial phenotype.

    Science.gov (United States)

    Zhang, Caili; Zhu, Suqin; Jatt, Abdul-Nabi; Zeng, Mingyong

    2016-01-01

    Quorum sensing (QS) is a cell-to-cell communication mechanism through which microbial cells communicate and regulate their wide variety of biological activities. N-acyl homoserine lactones (AHLs) are considered to be the most important QS signaling molecules produced by several Gram-negative bacteria. The present study aimed to screen the AHLs-producing bacteria from spoiled vacuum-packaged refrigerated turbot (Scophthalmus maximus) by biosensor assays, and the profiles of AHLs produced by these bacteria were determined using reversed-phase thin-layer chromatography (RP-TLC) and gas chromatography-mass spectrometry (GC-MS). Effects of exogenous AHLs and QS inhibitor (QSI) on the phenotypes (i.e., extracellular proteolytic activity and biofilm formation) of the AHLs-producing bacteria were also evaluated. Our results demonstrated that eight out of twenty-two isolates were found to produce AHLs. Three of the AHLs-producing isolates were identified as Serratia sp., and the other five were found to belong to the family of Aeromonas. Two isolates (i.e., S. liquefaciens A2 and A. sobria B1) with higher AHLs-producing activities were selected for further studies. Mainly, RP-TLC and GC-MS analysis revealed three AHLs, i.e., 3-oxo-C6-HSL, C8-HSL and C10-HSL were produced by S. liquefaciens A2, while five AHLs, i.e., C4-HSL, C6-HSL, C8-HSL, C10-HSL, and C12-HSL, were produced by A. sobria B1. Moreover, production of AHLs in both bacterial strains were found to be density-dependent, and the AHLs activity reached a maximum level in their middle logarithmic phase and decreased in the stationary phase. The addition of exogenous AHLs and QSI decreased the specific protease activity both of the Serratia A2 and Aeromonas B1. Exogenous AHLs inhibited the biofilm formation of Serratia A2 while it enhanced the biofilm formation in Aeromonas B1. QSI inhibited the specific protease activity and biofilm formation in both bacterial strains.

  9. Unusual long-chain N-acyl homoserine lactone production by and presence of quorum quenching activity in bacterial isolates from diseased tilapia fish.

    Directory of Open Access Journals (Sweden)

    Chien-Yi Chang

    Full Text Available Growth-dependent cell-cell communication termed quorum sensing is a key regulatory system in bacteria for controlling gene expression including virulence factors. In this study five potential bacterial pathogens including Bacillus sp. W2.2, Klebsiella sp. W4.2, Pseudomonas sp. W3 and W3.1 and Serratia sp. W2.3 were isolated from diseased Tilapia fish in Malaysia, supplied by the leading global fish supplier. Proteolytic activity assays confirmed that with the exception of Klebsiella sp. W4.2, all isolates showed distinct proteolytic activity. Furthermore Bacillus sp. W2.2 and Pseudomonas sp. strains W3 and W3.1 also displayed haemolytic activity. By using high resolution liquid chromatography mass spectrometry, we revealed the presence of unusually long-chain N-(3-oxohexadecanoyl-homoserine lactone (3-oxo-C16-HSL from Pseudomonas sp. W3.1 and N-dodecanoyl-homoserine lactone (C12-HSL from Serratia sp. W2.3, respectively. Interestingly, Pseudomonas sp. W3.1 also produced a wide range of Pseudomonas quinolone signalling (PQS molecules. Pseudomonas sp. W3 did not show any quorum sensing properties but possessed quorum quenching activity that inactivated AHLs. This study is the first documentation that shows unusual long-chain AHLs production in Serratia sp. and Pseudomonas sp. isolated from diseased fish and the latter also produce a wide range of PQS molecules.

  10. Homoserine Lactones Influence the Reaction of Plants to Rhizobia

    Directory of Open Access Journals (Sweden)

    Karl-Heinz Kogel

    2013-08-01

    Full Text Available Bacterial quorum sensing molecules not only grant the communication within bacterial communities, but also influence eukaryotic hosts. N-acyl-homoserine lactones (AHLs produced by pathogenic or beneficial bacteria were shown to induce diverse reactions in animals and plants. In plants, the reaction to AHLs depends on the length of the lipid side chain. Here we investigated the impact of two bacteria on Arabidopsis thaliana, which usually enter a close symbiosis with plants from the Fabaceae (legumes family and produce a long-chain AHL (Sinorhizobium meliloti or a short-chain AHL (Rhizobium etli. We demonstrate that, similarly to the reaction to pure AHL molecules, the impact, which the inoculation with rhizosphere bacteria has on plants, depends on the type of the produced AHL. The inoculation with oxo-C14-HSL-producing S. meliloti strains enhanced plant resistance towards pathogenic bacteria, whereas the inoculation with an AttM lactonase-expressing S. meliloti strain did not. Inoculation with the oxo-C8-HSL-producing R. etli had no impact on the resistance, which is in agreement with our previous hypothesis. In addition, plants seem to influence the availability of AHLs in the rhizosphere. Taken together, this report provides new insights in the role of N-acyl-homoserine lactones in the inter-kingdom communication at the root surface.

  11. Identification and Quantification of N-Acyl Homoserine Lactones Involved in Bacterial Communication by Small-Scale Synthesis of Internal Standards and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    Science.gov (United States)

    Leipert, Jan; Treitz, Christian; Leippe, Matthias; Tholey, Andreas

    2017-08-01

    N-acyl homoserine lactones (AHL) are small signal molecules involved in the quorum sensing of many gram-negative bacteria, and play an important role in biofilm formation and pathogenesis. Present analytical methods for identification and quantification of AHL require time-consuming sample preparation steps and are hampered by the lack of appropriate standards. By aiming at a fast and straightforward method for AHL analytics, we investigated the applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Suitable MALDI matrices, including crystalline and ionic liquid matrices, were tested and the fragmentation of different AHL in collision-induced dissociation MS/MS was studied, providing information about characteristic marker fragments ions. Employing small-scale synthesis protocols, we established a versatile and cost-efficient procedure for fast generation of isotope-labeled AHL standards, which can be used without extensive purification and yielded accurate standard curves. Quantitative analysis was possible in the low pico-molar range, with lower limits of quantification reaching from 1 to 5 pmol for different AHL. The developed methodology was successfully applied in a quantitative MALDI MS analysis of low-volume culture supernatants of Pseudomonas aeruginosa. [Figure not available: see fulltext.

  12. N-Acyl homoserine lactones as microorganism quorum sensing modulators:research advances%微生物群体感应调节信号分子N-酰化高丝氨酸内酯研究进展

    Institute of Scientific and Technical Information of China (English)

    余斌; 方园; 段迎超; 谢智宇; 李洪娟; 张恩; 刘宏民

    2011-01-01

    Bacterial quorum sensing demonstrates the ability of bacteria to control gene expression through detecting the minimal threshold stimulatory concentration of certain chemicals called auto inducers, which are secreted by self and/or other bacteria. Quorum sensing has been implicated in the control of bacterial behaviors such as the secretion of virulence factors,biofilm formation, bioluminescence production, conjugation, sporulation and swarming motility. Microorganism quorum sensing mediated by small molecules, including AIP, AI-2, DKPs, DPD and N-acyl homoserine lactones(AHL), has drawn wide attention in the last ten years. Especially the research on AHL has become a hot topic, a large number of literatures showed that AHL had potential biological activity such as antibacterial, antitumor, immunodepression, cell apoptosis inducer and so on. Much work has been done to explore the action mechanism of AHL to quorum sensing modulation, but it is remaining unclear. What's more, researches on the synthesis and structure-activity relationship (SAR) of AHL are still on the preliminary stage. Therefore, this paper summarizes the action mechanism, SAR and synthesis of AHL and the analogues, aiming to provide information helpful for new drug discovery and development%近10年来,小分子介导的微生物群体感应调节受到广泛关注.介导微生物群体感应调节的信号分子包括AIP、AI-2、DKPs、DPD、N-酰化高丝氨酸内酯(AHL)等,其中AHL成为研究热点,研究表明其具有潜在的抗菌、抗肿瘤、免疫抑制和诱导细胞凋亡等作用.目前对AHL介导微生物群体感应调节机制研究较多,而对于此类化合物的合成及其构效关系研究还处于初步阶段.本文就AHL类似物的群体感应调节机制、构效关系、生物合成和化学合成方法加以综述.

  13. Discovery of Pantoea rodasii strain ND03 that produces N-(3-Oxo-hexanoyl)-L-homoserine lactone.

    Science.gov (United States)

    Yunos, Nina Yusrina Muhamad; Tan, Wen-Si; Mohamad, Nur Izzati; Tan, Pui-Wan; Adrian, Tan-Guan-Sheng; Yin, Wai-Fong; Chan, Kok-Gan

    2014-05-23

    Proteobacteria use quorum sensing to regulate target gene expression in response to population density. Quorum sensing (QS) is achieved via so-called signalling molecules and the best-studied QS signalling system uses N-acyl homoserine lactones (AHLs). This study aimed to identify and characterize the production of AHLs by a bacterium ND03 isolated from a Malaysian tropical rainforest waterfall. Molecular identification showed that ND03 is a Pantoea sp. closely related to Pantoea rodasii. We used Chromobacterium violaceum CV026, an AHL biosensor for preliminary AHL production screening and then used high resolution triple quadrupole liquid chromatography-mass spectrometry, to confirm that P. rodasii strain ND03 produced N-(3-oxo-hexanoyl)-L-homoserine lactone (3-oxo-C6-HSL). To the best of our knowledge, this is the first report for such a discovery in P. rodasii strain ND03.

  14. Nonbioluminescent strains of Photobacterium phosphoreum produce the cell-to-cell communication signal N-(3-Hydroxyoctanoyl)homoserine lactone

    DEFF Research Database (Denmark)

    Flodgaard, Lars; Dalgaard, Paw; Andersen, Jens Bo

    2005-01-01

    Bioluminescence is a common phenotype in marine bacteria, such As Vibrio and Photobacterium species, and can be quorum regulated by N-acylated homoserine lactones (AHLs). We extracted a molecule that induced a bacterial AHL monitor (Agrobacterium tumefaciens NT1 [pZLR4]) from packed cod fillets......, which spoil due to growth of Photobacterium phosphoreum. Interestingly, AHLs were produced by 13 nonbioluminescent strains of P. phosphoreum isolated from the product. Of 177 strains of P. phosphoreum (including 18 isolates from this study), none of 74 bioluminescent strains elicited a reaction......) and shape to N-(3-hydroxyoctanoyl)homoserine lactone, and the presence of this molecule in culture supernatants from a nonbioluminescent strain of P. phosphoreum was confirmed by high-performance liquid chromatography-positive electrospray high-resolution mass spectrometry. Bioluminescence (in a non...

  15. The Pseudomonas aeruginosa autoinducer dodecanoyl-homoserine lactone inhibits the putrescine synthesis in human cells

    DEFF Research Database (Denmark)

    Kristiansen, S.; Bjarnsholt, Thomas; Adeltoft, D.

    2008-01-01

    Pseudomonas aeruginosa uses acyl-homoserine lactones to coordinate gene transcription in a process called quorum sensing (QS). The QS molecules C-4-HSL and C-12-oxo-HSL are synthesized from the universal precursor S-adenosyl methionine, which is also a precursor of polyamines in human cells....... Polyamines are required for mitotic cell division and peak during this phase. The polyamine putrescine is synthesized by ornithine decarboxylase (ODC) as a rate-limiting step. The ODC enzyme concentration also peaks during the mitotic phase. This peak is mediated by translation of ODC mRNA by the ITAF45...... protein, which translocates from the nuclear compartment to the cytoplasm in a phosphorylation-dependent manner. We observed that C-12-HSL-treated human epidermal cells had a higher cytoplasm-to-nuclear ITAF45 protein concentration and this translocation was dependent on the dephosphorylation of ITAF45...

  16. Homoserine Lactone as a Structural Key Element for the Synthesis of Multifunctional Polymers

    Directory of Open Access Journals (Sweden)

    Fabian Marquardt

    2017-04-01

    Full Text Available The use of bio-based building blocks for polymer synthesis represents a milestone on the way to “green” materials. In this work, two synthetic strategies for the preparation of multifunctional polymers are presented in which the key element is the functionality of homoserine lactone. First, the synthesis of a bis cyclic coupler based on a thiolactone and homoserine lactone is displayed. This coupler was evaluated regarding its regioselectivity upon reaction with amines and used in the preparation of multifunctional polymeric building blocks by reaction with diamines. Furthermore, a linear polyglycidol was functionalized with homoserine lactone. The resulting polyethers with lactone groups in the side chain were converted to cationic polymers by reaction with 3-(dimethylamino-1-propylamine followed by quaternization with methyl iodide.

  17. X-box binding protein 1 (XBP1s is a critical determinant of Pseudomonas aeruginosa homoserine lactone-mediated apoptosis.

    Directory of Open Access Journals (Sweden)

    Cathleen D Valentine

    Full Text Available Pseudomonas aeruginosa infections are associated with high mortality rates and occur in diverse conditions including pneumonias, cystic fibrosis and neutropenia. Quorum sensing, mediated by small molecules including N-(3-oxo-dodecanoyl homoserine lactone (C12, regulates P. aeruginosa growth and virulence. In addition, host cell recognition of C12 initiates multiple signalling responses including cell death. To gain insight into mechanisms of C12-mediated cytotoxicity, we studied the role of endoplasmic reticulum stress in host cell responses to C12. Dramatic protection against C12-mediated cell death was observed in cells that do not produce the X-box binding protein 1 transcription factor (XBP1s. The leucine zipper and transcriptional activation motifs of XBP1s were sufficient to restore C12-induced caspase activation in XBP1s-deficient cells, although this polypeptide was not transcriptionally active. The XBP1s polypeptide also regulated caspase activation in cells stimulated with N-(3-oxo-tetradecanoyl homoserine lactone (C14, produced by Yersinia enterolitica and Burkholderia pseudomallei, and enhanced homoserine lactone-mediated caspase activation in the presence of endogenous XBP1s. In C12-tolerant cells, responses to C12 including phosphorylation of p38 MAPK and eukaryotic initiation factor 2α were conserved, suggesting that C12 cytotoxicity is not heavily dependent on these pathways. In summary, this study reveals a novel and unconventional role for XBP1s in regulating host cell cytotoxic responses to bacterial acyl homoserine lactones.

  18. Isovaleryl-homoserine lactone, an unusual branched-chain quorum-sensing signal from the soybean symbiont Bradyrhizobium japonicum.

    Science.gov (United States)

    Lindemann, Andrea; Pessi, Gabriella; Schaefer, Amy L; Mattmann, Margrith E; Christensen, Quin H; Kessler, Aline; Hennecke, Hauke; Blackwell, Helen E; Greenberg, E Peter; Harwood, Caroline S

    2011-10-01

    Many species of Proteobacteria communicate by using LuxI-LuxR-type quorum-sensing systems that produce and detect acyl-homoserine lactone (acyl-HSL) signals. Most of the known signals are straight-chain fatty acyl-HSLs, and evidence indicates that LuxI homologs prefer fatty acid-acyl carrier protein (ACP) over fatty acyl-CoA as the acyl substrate for signal synthesis. Two related LuxI homologs, RpaI and BtaI from Rhodopseudomonas palustris and photosynthetic stem-nodulating bradyrhizobia, direct production of the aryl-HSLs p-coumaroyl-HSL and cinnamoyl-HSL, respectively. Here we report that BjaI from the soybean symbiont Bradyrhizobium japonicum USDA110 is closely related to RpaI and BtaI and catalyzes the synthesis of isovaleryl-HSL (IV-HSL), a branched-chain fatty acyl-HSL. We show that IV-HSL induces expression of bjaI, and in this way IV-HSL functions like many other acyl-HSL quorum-sensing signals. Purified histidine-tagged BjaI was an IV-HSL synthase, which was active with isovaleryl-CoA but not detectably so with isovaleryl-ACP. This suggests that the RpaI-BtaI-BjaI subfamily of acyl-HSL synthases may use CoA- rather than ACP-linked substrates for acyl-HSL synthesis. The bjaI-linked bjaR(1) gene is involved in the response to IV-HSL, and BjaR(1) is sensitive to IV-HSL at concentrations as low as 10 pM. Low but sufficient levels of IV-HSL (about 5 nM) accumulate in B. japonicum culture fluid. The low levels of IV-HSL synthesis have likely contributed to the fact that the quorum-sensing signal from this bacterium has not been described elsewhere.

  19. A simple, rapid, sensitive method detecting homoserine lactone (HSL)-related compounds in microbial extracts.

    Science.gov (United States)

    Singh, Maya Prakash; Greenstein, Michael

    2006-04-01

    A simple, rapid, sensitive microtiter plate method detecting N-acyl homoserine lactone (HSL)-related compounds was established using an Agrobacterium tumefaciens strain harboring a traG::lacZ/traR reporter gene responsive to HSLs. This strain did not produce its own HSL, but the traG::lacZ reporter gene was induced only when its transcription activator TraR detected a cognate exogenous HSL. Therefore, the assay was expected to be highly specific for HSL-related compounds. Induction of the reporter gene, leading to production of beta-galactosidase enzyme, was measured by using two different beta-galactosidase substrates, X-gal and Galacton-Star, for colorimetric and chemiluminometric detection, respectively. The screen was validated in both the 96-well and 384-well plate formats, and extracts derived from 696 different microbial isolates, mostly unidentified actinomycetes isolated from diverse locations, were tested. Crude extracts of 81 (11.64%) cultures tested positive for HSL-related compounds, and an additional 34 (4.8%) crude extracts showed a moderate to weak signal for HSLs. Data from the fractionated samples, however, suggested a much higher prevalence of HSL signals in these extracts. Of 144 crude extracts fractionated into 10 individual samples at a 10x concentration, 72 (50%) cultures tested positive for HSLs. Six cultures were active only in the crude extract, 18 were active both in crude and one or more of their fractions, and an additional 48 were active in just one or more of their fractions. This finding may be the first to suggest such a high prevalence of HSL-signals found in nature, and a large number of actinomycetes in our collection appeared to produce HSL-related compounds.

  20. Vibrational Spectra of N-Butyryl-Homoserine Lactone

    DEFF Research Database (Denmark)

    Bak, Jimmy; Spanget-Larsen, Jens

    in the solid state, and in liquid CCl4 solution. Quantum chemical calculations are performed in order to support the assignment of the measured vibrational bands and explain intermolecular interactions and solvent effects. The resulting designation of the reported spectral bands of C4-HSL lactone demonstrates...... spectra that resembles the measured one was possible. Here we report for the first time the key vibrational band of the monomer form....

  1. Systemic responses of barley to the 3-hydroxy-decanoyl-homoserine lactone producing plant beneficial endophyte Acidovorax radicis N35

    Directory of Open Access Journals (Sweden)

    Shengcai Han

    2016-12-01

    Full Text Available Quorum sensing auto-inducers of the N-acyl homoserine lactone (AHL type produced by Gram-negative bacteria have different effects on plants including stimulation on root growth and/or priming or acquirement of systemic resistance in plants. In this communication the influence of AHL production of the plant growth promoting endophytic rhizosphere bacterium Acidovorax radicis N35 on barley seedlings was investigated. A. radicis N35 produces 3-hydroxy-C10-homoserine lactone (3-OH-C10-HSL as the major AHL compound. To study the influence of this QS autoinducer on the interaction with barley, the araI-biosynthesis gene was deleted. The comparison of inoculation effects of the A. radicis N35 wild type and the araI mutant resulted in remarkable differences. While the N35 wild type colonized plant roots effectively in microcolonies, the araI mutant occurred at the root surface as single cells. Furthermore, in a mixed inoculum the wild type was much more prevalent in colonization than the araI mutant documenting that the araI mutation affected root colonization. Nevertheless, a significant plant growth promoting effect could be shown after inoculation of barley with the wild type and the araI mutant in soil after two months cultivation. While A. radicis N35 wild type showed only a very weak induction of early defense responses in plant RNA expression analysis, the araI mutant caused increased expression of flavonoid biosynthesis genes. This was corroborated by the accumulation of several flavonoid compounds such as saponarin and lutonarin in leaves of root inoculated barley seedlings. Thus, although the exact role of the flavonoids in this plant response is not clear yet, it can be concluded, that the synthesis of AHLs by A. radicis has implications on the perception by the host plant barley and thereby contributes to the establishment and function of the bacteria-plant interaction.

  2. Systemic Responses of Barley to the 3-hydroxy-decanoyl-homoserine Lactone Producing Plant Beneficial Endophyte Acidovorax radicis N35

    Science.gov (United States)

    Han, Shengcai; Li, Dan; Trost, Eva; Mayer, Klaus F.; Vlot, A. Corina; Heller, Werner; Schmid, Michael; Hartmann, Anton; Rothballer, Michael

    2016-01-01

    Quorum sensing auto-inducers of the N-acyl homoserine lactone (AHL) type produced by Gram-negative bacteria have different effects on plants including stimulation on root growth and/or priming or acquirement of systemic resistance in plants. In this communication the influence of AHL production of the plant growth promoting endophytic rhizosphere bacterium Acidovorax radicis N35 on barley seedlings was investigated. A. radicis N35 produces 3-hydroxy-C10-homoserine lactone (3-OH-C10-HSL) as the major AHL compound. To study the influence of this QS autoinducer on the interaction with barley, the araI-biosynthesis gene was deleted. The comparison of inoculation effects of the A. radicis N35 wild type and the araI mutant resulted in remarkable differences. While the N35 wild type colonized plant roots effectively in microcolonies, the araI mutant occurred at the root surface as single cells. Furthermore, in a mixed inoculum the wild type was much more prevalent in colonization than the araI mutant documenting that the araI mutation affected root colonization. Nevertheless, a significant plant growth promoting effect could be shown after inoculation of barley with the wild type and the araI mutant in soil after 2 months cultivation. While A. radicis N35 wild type showed only a very weak induction of early defense responses in plant RNA expression analysis, the araI mutant caused increased expression of flavonoid biosynthesis genes. This was corroborated by the accumulation of several flavonoid compounds such as saponarin and lutonarin in leaves of root inoculated barley seedlings. Thus, although the exact role of the flavonoids in this plant response is not clear yet, it can be concluded, that the synthesis of AHLs by A. radicis has implications on the perception by the host plant barley and thereby contributes to the establishment and function of the bacteria-plant interaction. PMID:28018401

  3. Involvement of calmodulin in regulation of primary root elongation by N-3-oxo-hexanoyl homoserine lactone in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Qian eZhao

    2015-01-01

    Full Text Available Many bacteria use signal molecules of low molecular weight to monitor their local population density and to coordinate their collective behavior in a process called quorum sensing (QS. N-acyl-homoserine lactones (AHLs are the primary QS signals among Gram-negative bacteria. AHL-mediated QS plays an essential role in diverse bacterial physiological processes. Recent evidence shows that plants are able to sense bacterial AHLs and respond to them appropriately. However, little is known about the mechanism by which plants perceive and transduce the bacterial AHLs within cells. In this study, we found that the stimulatory effect of N-3-oxo-hexanoyl homoserine lactone (3OC6-HSL on primary root elongation of Arabidopsis was abolished by the calmodulin (CaM antagonists N-(6-aminohexyl-5-chloro-1-naphthalene sulfonamide (W-7 and trifluoperazine (TFP. Western-blot and ELISA analysis revealed that the concentration of CaM protein in Arabidopsis roots increased after treatment with 1 μM 3OC6-HSL. Results from quantitative RT-PCR demonstrated that the transcription of all nine CaM genes in Arabidopsis genome was up-regulated in the plants treated with 3OC6-HSL. The loss-of-function mutants of each AtCaM gene (AtCaM1-9 were insensitive to 3OC6-HSL-stimulation of primary root elongation. On the other hand, the genetic evidence showed that CaM may not participates the inhibition of primary root length caused by application of long-chained AHLs such as C10-HSL and C12-HSL. Nevertheless, our results suggest that CaM is involved in the bacterial 3OC6-HSL signaling in plant cells. These data offer new insight into the mechanism of plant response to bacterial QS signals.

  4. Systemic Responses of Barley to the 3-hydroxy-decanoyl-homoserine Lactone Producing Plant Beneficial Endophyte Acidovorax radicis N35.

    Science.gov (United States)

    Han, Shengcai; Li, Dan; Trost, Eva; Mayer, Klaus F; Vlot, A Corina; Heller, Werner; Schmid, Michael; Hartmann, Anton; Rothballer, Michael

    2016-01-01

    Quorum sensing auto-inducers of the N-acyl homoserine lactone (AHL) type produced by Gram-negative bacteria have different effects on plants including stimulation on root growth and/or priming or acquirement of systemic resistance in plants. In this communication the influence of AHL production of the plant growth promoting endophytic rhizosphere bacterium Acidovorax radicis N35 on barley seedlings was investigated. A. radicis N35 produces 3-hydroxy-C10-homoserine lactone (3-OH-C10-HSL) as the major AHL compound. To study the influence of this QS autoinducer on the interaction with barley, the araI-biosynthesis gene was deleted. The comparison of inoculation effects of the A. radicis N35 wild type and the araI mutant resulted in remarkable differences. While the N35 wild type colonized plant roots effectively in microcolonies, the araI mutant occurred at the root surface as single cells. Furthermore, in a mixed inoculum the wild type was much more prevalent in colonization than the araI mutant documenting that the araI mutation affected root colonization. Nevertheless, a significant plant growth promoting effect could be shown after inoculation of barley with the wild type and the araI mutant in soil after 2 months cultivation. While A. radicis N35 wild type showed only a very weak induction of early defense responses in plant RNA expression analysis, the araI mutant caused increased expression of flavonoid biosynthesis genes. This was corroborated by the accumulation of several flavonoid compounds such as saponarin and lutonarin in leaves of root inoculated barley seedlings. Thus, although the exact role of the flavonoids in this plant response is not clear yet, it can be concluded, that the synthesis of AHLs by A. radicis has implications on the perception by the host plant barley and thereby contributes to the establishment and function of the bacteria-plant interaction.

  5. Paraoxonase 2 modulates a proapoptotic function in LS174T cells in response to quorum sensing molecule N-(3-oxododecanoyl)-L-homoserine lactone.

    Science.gov (United States)

    Tao, Shiyu; Luo, Yanwen; Bin He; Liu, Jie; Qian, Xi; Ni, Yingdong; Zhao, Ruqian

    2016-07-01

    A mucus layer coats the gastrointestinal tract and serves as the first line of intestinal defense against infection. N-acyl-homoserine lactone (AHL) quorum-sensing molecules produced by gram-negative bacteria in the gut can influence the homeostasis of intestinal epithelium. In this study, we investigated the effects of two representative long- and short-chain AHLs, N-3-(oxododecanoyl)-homoserine lactone (C12-HSL) and N-butyryl homoserine lactone (C4-HSL), on cell viability and mucus secretion in LS174T cells. C12-HSL but not C4-HSL significantly decreased cell viability by inducing mitochondrial dysfunction and activating cell apoptosis which led to a decrease in mucin expression. Pretreatment with lipid raft disruptor (Methyl-β-cyclodextrin, MβCD) and oxidative stress inhibitor (N-acetyl-L-cysteine, NAC) slightly rescued the viability of cells damaged by C12-HSL exposure, while the paraoxonase 2 (PON2) inhibitor (Triazolo[4,3-a]quinolone, TQ416) significantly affected recovering cells viability and mucin secretion. When LS174T cells were treated with C12-HSL and TQ416 simultaneously, TQ416 showed the maximal positive effect on cells viability. However, if cells were first treated with C12-HSL for 40 mins, and then TQ46 was added, the TQ416 had no effect on cell viability. These results suggest that the C12-HSL-acid process acts at an early step to activate apoptosis as part of C12-HSL's effect on intestinal mucus barrier function.

  6. N-hexanoyl-L-homoserine lactone, a mediator of bacterial quorum-sensing regulation, exhibits plant-dependent stability and may be inactivated by germinating Lotus corniculatus seedlings.

    Science.gov (United States)

    Delalande, Laurie; Faure, Denis; Raffoux, Aurélie; Uroz, Stéphane; D'Angelo-Picard, Cathy; Elasri, Miena; Carlier, Aurélien; Berruyer, Romain; Petit, Annik; Williams, Paul; Dessaux, Yves

    2005-03-01

    The half-life of N-hexanoyl-l-homoserine lactone (C6-HSL) was determined under various pH and temperature conditions, and in several plant environments. C6-HSL was sensitive to alkaline pH, a process that was also temperature-dependent. In addition, C6-HSL disappeared from plant environments, i.e. axenic monocot and dicot plants cultivated under gnotobiotic, hydroponic conditions, albeit with variable kinetics. The disappearance was rapid at the root system of legume plants such as clover or Lotus, and slow or non-existent at the root system of monocots such as wheat or corn. These variable kinetics were not dependent upon pH changes that may have affected the growth media of the plants. Furthermore, C6-HSL did not accumulate in the plant, and the plant did not produce inhibitors of the C6-HSL signal. HPLC analyses revealed that C6-HSL disappeared from the media, and hence, Lotus exhibited a natural C6-HSL inactivating ability. This ability was not specific for C6-HSL and allowed the degradation of other N-acyl-homoserine lactones such as 3-oxo-C6-HSL, 3-oxo-octanoyl-HSL and 3-oxo-decanoyl-HSL. Preliminary investigation revealed that the inactivating ability is temperature-dependant and possibly of enzymatic origin.

  7. Cloning and expression of quorum sensing N-acyl-homoserine synthase (LuxI gene detected in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Farzan Modarresi

    2016-05-01

    Full Text Available Objectives: In present study we aimed to clone the luxI gene encoding N-acyl-homoserine synthase detected in biofilm forming clinical isolates of Acinetobacter baumannii and study its expression in Escherichia coli transformants.Materials and Methods: Four A. baumannii hospital strains which demonstrated strong biofilm activity were selected in this investigation. The presence of luxI gene was detected using PCR technique. Purified PCR product DNA was initially cloned to pTG19 plasmid embedded with overhang 3'dT residue and transformed to Escherichia coli K12 DH5α (luxI- mutant. The gene was then recovered from agarose gel after digestion after digestion with DraI restriction enzyme and ligated by T4 DNA ligase into pET28a expression vector using NdeI and XhoI enzymes. Recombinant (pET28a + luxI was transformed into E. coli BL21 (DE3 containing knockout luxI- gene. The luxI putative gene was further detected in transformants by colony PCR. Expression of the luxI gene in the recombinant E. coli BL21 cells was studied by quantitative real time PCR (qRT-PCR and the presence of N-acyl-homoserine lactone (AHL in wild types and the transformants were checked by colorimetric assay and Fourier Transform Infra- Red (FT-IR.Results: In our study, we found successful cloning of AHL from A. baumannii strain 23 which showed high biofilm. The presence of luxI gene in recombinant E. coli BL21 was confirmed by PCR. There was four fold increases in expression of luxI in the transformants (P ≤ 0.05. To verify the AHL synthesis, it was found that, strain 23 and the transformants showed highest amount of AHL activity (OD = 1.524. The FT-IR analysis indicated stretching C=O bond of the lactone ring and primary amides (N=H at 1764.69 cm-1 and 1659.23 cm-1 respectively.Conclusion: From above results we concluded that, luxI and AHL are the only quorum sensing elements existed in A. baumannii and pET28a vector allows efficient AHL expression in E. coli BL21

  8. Transgenic Amorphophallus konjac expressing synthesized acyl-homoserine lactonase (aiiA) gene exhibit enhanced resistance to soft rot disease.

    Science.gov (United States)

    Ban, Huifang; Chai, Xinli; Lin, Yongjun; Zhou, Ying; Peng, Donghai; Zhou, Yi; Zou, Yulan; Yu, Ziniu; Sun, Ming

    2009-12-01

    Amorphophallus konjac is an important economic crop widely used in health products and biomaterials. However, this monocotyledonous plant's production is seriously restricted by soft rot disease. Some Bacillus thuringiensis strains generate an endocellular acyl homoserine lactonase (AiiA), which has inhibitory effect on soft rot pathogen through disrupting the signal molecules (N-acylhomoserine lactones, AHL) of their Quorum Sensing system. The aim of our study is to obtain transgenic A. konjac expressing AiiA protein and exhibiting resistance to soft rot. But till now, there is not any report about exogenous gene transformation in A. konjac. In this research, an Agrobacterium-mediated genetic transformation system was constructed. An aiiA gene was synthesized according to the codon usage in A. konjac. Embryogenic callus was infected with the A. tumefaciens strain EHA105 harboring the plant transformation plasmid pU1301 plus synthesized aiiA gene. After antibiotics screening, 34 plants were obtained. PCR analysis showed that positive amplified fragments were present in 21 out of these 34 lines. Southern blot analysis indicated that aiiA gene had integrated into the genome of A. konjac. Western blotting demonstrated that the target protein of interest was reactive with the antibody against AiiA. Further disease resistance detection revealed that all of the tested transgenic A. konjac lines exhibited high resistance to soft rot bacteria Erwinia carotovora subsp. Carotovora (Ecc) SCG1. The protocol is useful for the quality improvement of A. konjac through genetic transformation.

  9. Influence and mechanism of N-(3-oxooxtanoyl)-L-homoserine lactone (C8-oxo-HSL) on biofilm behaviors at early stage

    Institute of Scientific and Technical Information of China (English)

    Siqing Xia; Lijie Zhou; Zhiqiang Zhang; Jixiang Li

    2012-01-01

    N-acyl-homoserines quenching,enzymatic quenching of bacterial quorum sensing,has recently applied to mitigate biofilm in membrane bioreactor.However,the effect of AHLs on the behavior of biofilm formation is still sparse.In this study,Pseudomonas aeruginosa biofilm was formed on ultra-filtration membrane under a series of N-(3-oxooxtanoyl)-L-homoserine lactone (Cs-oxo-HSL)concentrations.Diffusing Cs-oxo-HSL increased the growth rate of cells on biofilm where the concentration of Cs-oxo-HSL was over 10-7 g/L.The C8-oxo-HSL gradient had no observable influence on cell density and extracellular polymeric substances of biofilm with over 10-7 g/L Cs-oxo-HSL.Surprisingly,10-11-10-8 g/L of Cs-oxo-HSL had no effect on cell growth in liquid culture.The cell analysis demonstrated that the quorum sensing system might enhance the growth of neighboring cells in contact with surfaces into biofilm and may influence the structure and organization of biofilm.

  10. Influence and mechanism of N-(3-oxooxtanoyl)-L-homoserine lactone (C8-oxo-HSL) on biofilm behaviors at early stage.

    Science.gov (United States)

    Xia, Siqing; Zhou, Lijie; Zhang, Zhiqiang; Li, Jixiang

    2012-01-01

    N-acyl-homoserines quenching, enzymatic quenching of bacterial quorum sensing, has recently applied to mitigate biofilm in membrane bioreactor. However, the effect of AHLs on the behavior of biofilm formation is still sparse. In this study, Pseudomonas aeruginosa biofilm was formed on ultra-filtration membrane under a series of N-(3-oxooxtanoyl)-L-homoserine lactone (Cs-oxo-HSL) concentrations. Diffusing C8-oxo-HSL increased the growth rate of cells on biofilm where the concentration of C8-oxo-HSL was over 10(-7) g/L. The C8-oxo-HSL gradient had no observable influence on cell density and extracellular polymeric substances of biofilm with over 10(-7) g/L C8-oxo-HSL. Surprisingly, 10(-11)-10(-8) g/L of C8-oxo-HSL had no effect on cell growth in liquid culture. The cell analysis demonstrated that the quorum sensing system might enhance the growth of neighboring cells in contact with surfaces into biofilm and may influence the structure and organization of biofilm.

  11. A proteomic analysis of Arabidopsis thaliana seedling responses to 3-oxo-octanoyl-homoserine lactone, a bacterial quorum-sensing signal

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Chunjuan, E-mail: chunjuanjay@163.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Liu, Fang, E-mail: liufang830818@126.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Zhao, Qian, E-mail: zhqbluesea@163.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Jia, Zhenhua, E-mail: zhenhuaj@hotmail.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Song, Shuishan, E-mail: shuishans@hotmail.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer 3OC8-HSL can change the expression of diverse proteins in Arabidopsis. Black-Right-Pointing-Pointer 3OC8-HSL responsive proteins were identified using MALDI-TOF-MS. Black-Right-Pointing-Pointer Plant could have an extensive range of functional responses to bacterial AHL. -- Abstract: N-acyl-homoserine lactones (AHLs) are a class of bacterial quorum-sensing (QS) signals that are commonly used by Gram-negative bacteria for cell-to-cell communication. Recently, it has become evident that AHLs can regulate plant root growth and trigger plant defense responses; however, little is known about the plant response mechanisms to bacterial QS signals. In this study, we used a proteomic approach to investigate the responses of Arabidopsis thaliana seedlings to N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL), a bacterial QS signal. The results revealed that the abundance of 53 protein spots was significantly altered; two thirds of these proteins were found to be up-regulated after 3OC8-HSL treatment. Thirty-four proteins were identified using MALDI-TOF-MS. These 3OC8-HSL-responsive proteins, in addition to one protein of unknown function, are implicated in a variety of physiological processes, including metabolism of carbohydrate and energy, protein biosynthesis and quality control systems, defense response and signal transduction and cytoskeleton remodeling. Our bioinformatic analysis indicated that the chloroplasts are the intracellular organelles most influenced by the exposure to 3OC8-HSL. Our data indicate that plants have an extensive range of functional responses to bacterial AHLs that may play important roles in the interaction between plants and bacteria.

  12. A genetically engineered whole-cell pigment-based bacterial biosensing system for quantification of N-butyryl homoserine lactone quorum sensing signal.

    Science.gov (United States)

    Yong, Yang-Chun; Zhong, Jian-Jiang

    2009-09-15

    N-acyl homoserine lactone (AHL) is a widely conserved quorum sensing (QS) signal of gram-negative bacteria and has received attention in fighting against human diseases and environmental pollution. However, a method for quantifying AHL is lacking although it is urgently required for diagnosis and bioprocess manipulation. This work screened out an aromatics degrader Pseudomonas aeruginosa for biosensing system development, which produced a blue-green pigment regulated by the RhlI-RhlR QS system. By taking advantage of the recognition of N-butyryl homoserine lactone (BHL, the signal molecule of RhlI-RhlR QS system and an AHL) by the product of rhlR, a new whole-cell biosensor P. aeruginosa Delta rhlIR/pYC-rhlR (rhlI(-)rhlR(++)) was developed. It was constructed through abolishing its BHL production by in-frame deletion of rhlIR and over-expressing rhlR by introducing a multi-copy plasmid pYC-rhlR into Delta rhlIR. By using the pigment production which responded to exogenous BHL as biosensor output, BHL quantification in samples was simply done spectrophotometrically. Under optimum conditions, the calibration curve had the limit of detection (LOD), the 50% activation/effect concentration, the limit of quantification (LOQ), and the quantitative detection range of 1.3 nM, 2.77+/-0.45 microM, 5.7 nM and 0.11-49.7 microM, respectively. The biosensor output was stable, culture samples could be stored 10 days under -20 degrees C, and this sensing system was resistant to interferences by toxic aromatic pollutants. It was successfully applied to environmental samples even without extraction. The new whole-cell biosensing system provided a simple, stable, toxic pollutants-tolerant, and cost-effective tool for quantitative investigation of the QS signals' role in environmental processes.

  13. Mucin 3 is involved in intestinal epithelial cell apoptosis via N-(3-oxododecanoyl)-L-homoserine lactone-induced suppression of Akt phosphorylation.

    Science.gov (United States)

    Taguchi, Ryoko; Tanaka, Shinya; Joe, Ga-Hyun; Maseda, Hideaki; Nomura, Nobuhiko; Ohnishi, Junji; Ishizuka, Satoshi; Shimizu, Hidehisa; Miyazaki, Hitoshi

    2014-07-15

    N-acyl-homoserine lactones (AHL) are quorum-sensing molecules in bacteria that play important roles in regulating virulence gene expression in pathogens such as Pseudomonas aeruginosa. The present study compared responses between undifferentiated and differentiated Caco-2 cells to N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL). A low concentration of 3-oxo-C12-HSL (30 μM) is sufficient to reduce viability accompanied by apoptosis via the suppression of phosphorylation by Akt in undifferentiated Caco-2 cells. The suppression of Akt phosphorylation appears specific in 3-oxo-C12-HSL, because other AHLs did not influence the phosphorylation status of Akt. The reduced viability induced by 3-oxo-C12-HSL was partially recovered by constitutively active Akt overexpression in undifferentiated Caco-2 cells. Since mucin is considered a vital component of the gut barrier, we investigated whether mucin protects cellular functions induced by 3-oxo-C12-HSL in undifferentiated Caco-2 cells. The results showed that mucin protected undifferentiated Caco-2 cells from apoptosis induced by 3-oxo-C12-HSL. 3-Oxo-C12-HSL did not induce cell death in differentiated Caco-2 cells that expressed higher levels of mucin 3 (MUC3) than undifferentiated Caco-2 cells. In addition, 3-oxo-C12-HSL promoted cell death in undifferentiated Caco-2 cells transfected with MUC3 siRNA and reduced MUC3 expression in undifferentiated Caco-2 cells. Therefore, MUC3 might be responsible for the survival of undifferentiated intestinal epithelial cells in the presence of 3-oxo-C12-HSL through regulating Akt phosphorylation. In conclusion, 3-oxo-C12-HSL might influence the survival of undifferentiated intestinal epithelial cells as well as interactions between these cells and pathogens.

  14. Pseudomonas aeruginosa biofilm-associated homoserine lactone C12 rapidly activates apoptosis in airway epithelia.

    Science.gov (United States)

    Schwarzer, Christian; Fu, Zhu; Patanwala, Maria; Hum, Lauren; Lopez-Guzman, Mirielle; Illek, Beate; Kong, Weidong; Lynch, Susan V; Machen, Terry E

    2012-05-01

    Pseudomonas aeruginosa (PA) forms biofilms in lungs of cystic fibrosis (CF) patients, a process regulated by quorum-sensing molecules including N-(3-oxododecanoyl)-l-homoserine lactone (C12). C12 (10-100 µM) rapidly triggered events commonly associated with the intrinsic apoptotic pathway in JME (CF ΔF508CFTR, nasal surface) epithelial cells: depolarization of mitochondrial (mito) membrane potential (Δψ(mito)) and release of cytochrome C (cytoC) from mitos into cytosol and activation of caspases 3/7, 8 and 9. C12 also had novel effects on the endoplasmic reticulum (release of both Ca(2+) and ER-targeted GFP and oxidized contents into the cytosol). Effects began within 5 min and were complete in 1-2 h. C12 caused similar activation of caspases and release of cytoC from mitos in Calu-3 (wtCFTR, bronchial gland) cells, showing that C12-triggered responses occurred similarly in different airway epithelial types. C12 had nearly identical effects on three key aspects of the apoptosis response (caspase 3/7, depolarization of Δψ(mito) and reduction of redox potential in the ER) in JME and CFTR-corrected JME cells (adenoviral expression), showing that CFTR was likely not an important regulator of C12-triggered apoptosis in airway epithelia. Exposure of airway cultures to biofilms from PAO1wt caused depolarization of Δψ(mito) and increases in Ca(cyto) like 10-50 µM C12. In contrast, biofilms from PAO1ΔlasI (C12 deficient) had no effect, suggesting that C12 from P. aeruginosa biofilms may contribute to accumulation of apoptotic cells that cannot be cleared from CF lungs. A model to explain the effects of C12 is proposed. © 2012 Blackwell Publishing Ltd.

  15. High-Sensitivity Monoclonal Antibodies Specific for Homoserine Lactones Protect Mice from Lethal Pseudomonas aeruginosa Infections

    Science.gov (United States)

    Downham, Christina; Broadbent, Ian; Charlton, Keith; Porter, Andrew J.

    2014-01-01

    A number of bacteria, including pathogens like Pseudomonas aeruginosa, utilize homoserine lactones (HSLs) as quorum sensing (QS) signaling compounds and engage in cell-to-cell communication to coordinate their behavior. Blocking this bacterial communication may be an attractive strategy for infection control as QS takes a central role in P. aeruginosa biology. In this study, immunomodulation of HSL molecules by monoclonal antibodies (MAbs) was used as a novel approach to prevent P. aeruginosa infections and as tools to detect HSLs in bodily fluids as a possible first clue to an undiagnosed Gram-negative infection. Using sheep immunization and recombinant antibody technology, a panel of sheep-mouse chimeric MAbs were generated which recognized HSL compounds with high sensitivity (nanomolar range) and cross-reactivity. These MAbs retained their nanomolar sensitivity in complex matrices and were able to recognize HSLs in P. aeruginosa cultures grown in the presence of urine. In a nematode slow-killing assay, HSL MAbs significantly increased the survival of worms fed on the antibiotic-resistant strain PA058. The therapeutic benefit of these MAbs was further studied using a mouse model of Pseudomonas infection in which groups of mice treated with HSL-2 and HSL-4 MAbs survived, 7 days after pathogen challenge, in significantly greater numbers (83 and 67%, respectively) compared with the control groups. This body of work has provided early proof-of-concept data to demonstrate the potential of HSL-specific, monoclonal antibodies as theranostic clinical leads suitable for the diagnosis, prevention, and treatment of life-threatening bacterial infections. PMID:24185854

  16. Nonbioluminescent strains of Photobacterium phosphoreum produce the cell-to-cell communication signal N-(3-Hydroxyoctanoyl)homoserine lactone

    DEFF Research Database (Denmark)

    Flodgaard, Lars; Dalgaard, Paw; Andersen, Jens Bo

    2005-01-01

    in the AHL monitor, whereas 48 of 103 nonbioluminescent strains did produce AHLs. AHLs were also detected in Aeromonas spp., but not in Shewanella strains. Thin-layer chromatographic profiles of cod extracts and P. phosphoreum culture supernatants identified a molecule similar in relative mobility (R-f value......) and shape to N-(3-hydroxyoctanoyl)homoserine lactone, and the presence of this molecule in culture supernatants from a nonbioluminescent strain of P. phosphoreum was confirmed by high-performance liquid chromatography-positive electrospray high-resolution mass spectrometry. Bioluminescence (in a non...

  17. Rosmarinic acid is a homoserine lactone mimic produced by plants that activates a bacterial quorum-sensing regulator.

    Science.gov (United States)

    Corral-Lugo, Andrés; Daddaoua, Abdelali; Ortega, Alvaro; Espinosa-Urgel, Manuel; Krell, Tino

    2016-01-05

    Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a plant-derived compound that functioned as an HSL mimic. In vitro assays showed that rosmarinic acid bound to the quorum-sensing regulator RhlR of Pseudomonas aeruginosa PAO1 and competed with the bacterial ligand N-butanoyl-homoserine lactone (C4-HSL). Furthermore, rosmarinic acid stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL. In P. aeruginosa, rosmarinic acid induced quorum sensing-dependent gene expression and increased biofilm formation and the production of the virulence factors pyocyanin and elastase. Because P. aeruginosa PAO1 infection induces rosmarinic acid secretion from plant roots, our results indicate that rosmarinic acid secretion is a plant defense mechanism to stimulate a premature quorum-sensing response. P. aeruginosa is a ubiquitous pathogen that infects plants and animals; therefore, identification of rosmarinic acid as an inducer of premature quorum-sensing responses may be useful in agriculture and inform human therapeutic strategies.

  18. Cellular effects of bacterial N-3-Oxo-dodecanoyl-L-Homoserine lactone on the sponge Suberites domuncula (Olivi, 1792: insights into an intimate inter-kingdom dialogue.

    Directory of Open Access Journals (Sweden)

    Johan Gardères

    Full Text Available Sponges and bacteria have lived together in complex consortia for 700 million years. As filter feeders, sponges prey on bacteria. Nevertheless, some bacteria are associated with sponges in symbiotic relationships. To enable this association, sponges and bacteria are likely to have developed molecular communication systems. These may include molecules such as N-acyl-L-homoserine lactones, produced by Gram-negative bacteria also within sponges. In this study, we examined the role of N-3-oxododecanoyl-L-homoserine lactone (3-oxo-C12-HSL on the expression of immune and apoptotic genes of the host sponge Suberites domuncula. This molecule seemed to inhibit the sponge innate immune system through a decrease of the expression of genes coding for proteins sensing the bacterial membrane: a Toll-Like Receptor and a Toll-like Receptor Associated Factor 6 and for an anti-bacterial perforin-like molecule. The expression of the pro-apoptotic caspase-like 3/7 gene decreased as well, whereas the level of mRNA of anti-apoptotic genes Bcl-2 Homolog Proteins did not change. Then, we demonstrated the differential expression of proteins in presence of this 3-oxo-C12-HSL using 3D sponge cell cultures. Proteins involved in the first steps of the endocytosis process were highlighted using the 2D electrophoresis protein separation and the MALDI-TOF/TOF protein characterization: α and β subunits of the lysosomal ATPase, a cognin, cofilins-related proteins and cytoskeleton proteins actin, α tubulin and α actinin. The genetic expression of some of these proteins was subsequently followed. We propose that the 3-oxo-C12-HSL may participate in the tolerance of the sponge apoptotic and immune systems towards the presence of bacteria. Besides, the sponge may sense the 3-oxo-C12-HSL as a molecular evidence of the bacterial presence and/or density in order to regulate the populations of symbiotic bacteria in the sponge. This study is the first report of a bacterial secreted

  19. Cellular effects of bacterial N-3-Oxo-dodecanoyl-L-Homoserine lactone on the sponge Suberites domuncula (Olivi, 1792): insights into an intimate inter-kingdom dialogue.

    Science.gov (United States)

    Gardères, Johan; Henry, Joël; Bernay, Benoit; Ritter, Andrès; Zatylny-Gaudin, Céline; Wiens, Matthias; Müller, Werner E G; Le Pennec, Gaël

    2014-01-01

    Sponges and bacteria have lived together in complex consortia for 700 million years. As filter feeders, sponges prey on bacteria. Nevertheless, some bacteria are associated with sponges in symbiotic relationships. To enable this association, sponges and bacteria are likely to have developed molecular communication systems. These may include molecules such as N-acyl-L-homoserine lactones, produced by Gram-negative bacteria also within sponges. In this study, we examined the role of N-3-oxododecanoyl-L-homoserine lactone (3-oxo-C12-HSL) on the expression of immune and apoptotic genes of the host sponge Suberites domuncula. This molecule seemed to inhibit the sponge innate immune system through a decrease of the expression of genes coding for proteins sensing the bacterial membrane: a Toll-Like Receptor and a Toll-like Receptor Associated Factor 6 and for an anti-bacterial perforin-like molecule. The expression of the pro-apoptotic caspase-like 3/7 gene decreased as well, whereas the level of mRNA of anti-apoptotic genes Bcl-2 Homolog Proteins did not change. Then, we demonstrated the differential expression of proteins in presence of this 3-oxo-C12-HSL using 3D sponge cell cultures. Proteins involved in the first steps of the endocytosis process were highlighted using the 2D electrophoresis protein separation and the MALDI-TOF/TOF protein characterization: α and β subunits of the lysosomal ATPase, a cognin, cofilins-related proteins and cytoskeleton proteins actin, α tubulin and α actinin. The genetic expression of some of these proteins was subsequently followed. We propose that the 3-oxo-C12-HSL may participate in the tolerance of the sponge apoptotic and immune systems towards the presence of bacteria. Besides, the sponge may sense the 3-oxo-C12-HSL as a molecular evidence of the bacterial presence and/or density in order to regulate the populations of symbiotic bacteria in the sponge. This study is the first report of a bacterial secreted molecule acting on

  20. Identification, cloning and lactonase activity of recombinant protein of N-acyl homoserine lactonase (AiiA from Bacillus thuringiensis 147-115-16 strain.

    Directory of Open Access Journals (Sweden)

    Alvaro Mauricio Florez Escobar

    2014-06-01

    Full Text Available Título en español: Identificación, clonación y actividad lactonasa de la proteína recombinante de N-ácil homoserina lactonasa (AiiA de Bacillus thuringiensis cepa 147-115-16 Short title: N-acyl homoserine lactonase (AiiA from Bacillus thuringiensis Abstract: The quorum-quenching N-acyl homoserine lactonases are a family of bacterial metalloenzymes that participate in degradation of N-acyl homoserine lactones (AHLs, disrupting the quorum sensing system of gram negative bacterial species. From a collection of Bacillus thuringiensis strains isolated in Colombia from plants and exhibiting toxic activity against lepidopteran insects, 310 bacterial isolates were tested to determine lactonase activity by using biosensor systems in presence of synthetic N-hexanoyl-L-homoserine lactone (C6-HSL and N-octanoyl-L-homoserine lactone (C8-HSL. From them, 251 strains showed degrading activity to both C6-HSL and C8-HSL, 57% exhibited degrading activity to C6-HSL and 43% to C8-HSL. One B. thuringiensis strain, denoted as 147-115-16, that exhibit high degrading activity to C6-HSL and C8-HSL, was able to attenuate soft rot symptoms in infected potato slices with Pectobacterium carotovorum. This strain contains an homologous of the aiiA gene that was cloned, sequenced and expressed in Esherichia coli DE3. The recombinant protein AiiA147-11516 displays activity to C6-HSL, C8-HSL, N-(β-ketocaproyl (3-O-C6-HSL and N-3-oxo-dodecanoyl (3-O-C12-HSL. The recombinant strain in the presence of P. caratovorum cultures was able to attenuate the infection, suggesting that it interferes either with the accumulation or with the response to the AHLs signals. Acording to this data and based on previous report from recombinant AiiA147-11516, this enzyme exhibits activity to a wide range of catalytic substrates suggesting its industrial application in the disease control programs through plants transformation.Key words: lactones, Quorum sensing, Quorum quenching, Lactonases

  1. Morphological changes in Proteus mirabilis O18 biofilm under the influence of a urease inhibitor and a homoserine lactone derivative.

    Science.gov (United States)

    Czerwonka, Grzegorz; Arabski, Michał; Wąsik, Sławomir; Jabłońska-Wawrzycka, Agnieszka; Rogala, Patrycja; Kaca, Wiesław

    2014-03-01

    Proteus mirabilis is a pathogenic gram-negative bacterium that frequently causes kidney infections, typically established by ascending colonization of the urinary tract. The present study is focused on ureolytic activity and urease inhibition in biofilms generated by P. mirabilis O18 cells. Confocal microscopy revealed morphological alterations in biofilms treated with urea and a urease inhibitor (acetohydroxamic acid, AHA), as some swarmer cells were found to protrude from the biofilm. The presence of a quorum-sensing molecule (N-butanoyl homoserine lactone, BHL) increased biofilm thickness and its ureolytic activity. Laser interferometric determination of diffusion showed that urea easily diffuses through P. mirabilis biofilm, while AHA is blocked. This may suggest that the use of urease inhibitors in CAUTIs may by less effective than in other urease-associated infections. Spectroscopic studies revealed differences between biofilm and planktonic cells indicating that polysaccharides and nucleic acids are involved in extracellular matrix and biofilm formation.

  2. Profiling acylated homoserine lactones in Yersinia ruckeri and influence of exogenous acyl homoserine lactones and known quorum-sensing inhibitors on protease production

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Nielsen, Kristian Fog; Dalsgaard, Inger

    2007-01-01

    To profile the quorum-sensing (QS) signals in Yersinia ruckeri and to examine the possible regulatory link between QS signals and a typical QS-regulated virulence phenotype, a protease. Methods and Results: Liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) showed that Y. ruckeri...

  3. Research on Prokaryotic Expression of Vibrio parahaemolyticus vanM Gene and N-acyl-homoserine Lactone Identification%副溶血性弧菌vanM基因原核表达及酰基高丝氨酸内酯信号分子鉴定研究

    Institute of Scientific and Technical Information of China (English)

    吴葵; 吴清平; 张菊梅; 徐晓可

    2015-01-01

    从副溶血性弧菌ATCC33847扩增vanM基因,连接到pMD 19-T载体进行克隆测序和序列比对;将测序正确的vanM序列经NdeI和EcoRI酶切后连接到pET22b;以IPTG诱导vanM基因在BL21(DE3)中表达;利用acyl-HSL报告菌株KYC55检测ATCC33847和带有vanM基因的大肠杆菌的acyl-HSL活性;萃取VanM合成的acyl-HSL信号分子,经HPLC-MS测试后与标准品进行对比分析.成功测序了ATCC33847 vanM基因,与鳗弧菌vanM基因序列相似性达到57%;并构建了pET22b-vanM表达质粒,以0.6 mmol/L IPTG诱导BL21 (DE3)表达系统时VanM融合蛋白表达量最大;经过KYC55检测ATCC33847和带有pET22b-vanM的大肠杆菌能够产生acyl-HSL活性;HPLC-MS分析显示,ATCC33847和携带pET22b-vanM的BL21(DE3)萃取物中含有3-Hydroxybutanoyl-HSL (3-OH-C4-HSL)和3-Hydroxydecanoyl-HSL (3-OH-C10-HSL)信号分子.本研究克隆表达了副溶血性弧菌vanM,首次证明了副溶血性弧菌利用VanM信号分子合成酶合成acyl-HSL信号分子3-OH-C4-HSL和3-OH-C10-HSL.

  4. Characterization of N-butanoyl-L-homoserine lactone (C4-HSL) deficient clinical isolates of Pseudomonas aeruginosa.

    Science.gov (United States)

    Boşgelmez-Tinaz, Gülgün; Ulusoy, Seyhan

    2008-01-01

    In the opportunistic pathogen Pseudomonas aeruginosa, the production of several virulence factors such as elastase, rhamnolipids and pyocyanin depends on cell-to-cell signaling or quorum sensing (QS) involving N-acylhomoserine lactone (AHL) signal molecules. In vitro studies with laboratory strains and virulence studies in animals with these same strains have demonstrated the contribution of QS to the pathogenesis of P. aeruginosa. However, the importance of P. aeruginosa QS systems in the development of human infections is not clearly known. In order to determine if deficiency within the QS system compromises the ability of P. aeruginosa to cause infections in humans, we collected 50 P. aeruginosa clinical isolates. Phenotypic characterization showed that isolates I-457, I-458, I-459 and I-461 were defective in the production of N-butanoyl-l-homoserine lactone (C4-HSL) signaling molecule and virulence factors elastase, protease, pyocyanin and rhamnolipids. Analysis of the sequences of the lasR, lasI, rhlR and rhlI genes of these four isolates showed that two of the four isolates had mutational defects in both rhlR and rhlI genes while other two isolates were only mutated in the rhlI gene. The combination of rhlR and rhlI mutations or only rhlI mutation probably explains their C4-HSL and virulence factors deficiencies. These observations suggest that QS deficient P. aeruginosa clinical isolates are able to cause infections and that in addition to known virulence factors, factors yet unidentified may contribute to the pathogenesis of P. aeruginosa.

  5. Quorum sensing signal molecules (acylated homoserine lactones) in Gram-negative fish pathogenic bacteria

    DEFF Research Database (Denmark)

    Bruhn, Jesper Bartholin; Dalsgaard, Inger; Nielsen, K.F.

    2005-01-01

    and plant-pathogenic bacteria. A total of 59 strains, representing 9 different fish pathogenic species, were tested against 2 AHL monitor bacteria (Agrobacterium tumefaciens NT1 [pZLR4] and Chromobacterium violaceum CV026) in a well diffusion assay and by thin-layer chromatography (TLC). Representative...

  6. Inhibition of Lux quorum-sensing system by synthetic N-acyl-L-homoserine lactone analogous

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the present study, we investigated the inhibition of the Lux quorum-sensing system by N-acyi cyclopentylamine (Cn-CPA). The Lux quorum-sensing system regulates luminescence gene expression in Vibriofischeri. We have already reported on the synthesis of Cn-CPA and their abilities as inhibitors of the quorum-sensing systems in Pseudomonas aeruginosa and Serratia marcescens. In the case of Pseudomonas aeruginosa (Las and Rhl quorum-sensing system) and Serratia marcescens (Spn quorum-sensing system), specific Cn-CPA with a particular acyi chain length showed the strongest inhibitory effect. In the case of the Lux quorum-sensing system, it was found that several kinds of Cn-CPA with a range from C5 to C10 showed similar strong inhibitory effects. Moreover, the inhibitory effect of Cn-CPA on the Lux quorum-sensing system was stronger than that of halogenated furanone, a natural quorum-sensing inhibitor.

  7. Global and Phylogenetic Distribution of Quorum Sensing Signals, Acyl Homoserine Lactones, in the Family of Vibrionaceae

    DEFF Research Database (Denmark)

    Rasmussen, Bastian Barker; Nielsen, Kristian Fog; Machado, Henrique;

    2014-01-01

    in the environment has remained unclear. Three hundred and one Vibrionaceae strains were collected on a global research cruise and the prevalence and profile of AHL signals in this global collection were determined. AHLs were detected in 32 of the 301 strains using Agrobacterium tumefaciens and Chromobacterium...

  8. Global and Phylogenetic Distribution of Quorum Sensing Signals, Acyl Homoserine Lactones, in the Family of Vibrionaceae

    DEFF Research Database (Denmark)

    Rasmussen, Bastian Barker; Nielsen, Kristian Fog; Machado, Henrique

    2014-01-01

    homology, however not with geographical location. In conclusion, a wide range of AHL signals are produced by a number of clades in the Vibrionaceae family and these results will allow future investigations of inter- and intra-species interactions within this cosmopolitan family of marine bacteria....

  9. Exploring O-stannyl ketyl and acyl radical cyclizations for the synthesis of γ-lactone-fused benzopyrans and benzofurans.

    Science.gov (United States)

    Santoso, Helen; Casana, Myriam I; Donner, Christopher D

    2014-01-07

    The synthesis of a series of γ-lactone-fused benzopyrans and benzofurans, analogues of the pyranonaphthoquinone antibiotics, is reported. Preparation of the heterocycles was achieved by either O-stannyl ketyl or acyl radical cyclization of benzaldehyde precursors followed by oxidation to give the pyrano- and furanobenzoquinone systems. The observed diastereoselectivity during O-stannyl ketyl radical cyclization is influenced by aromatic substitution ortho to the aldehyde, whilst acyl radical cyclization followed by stereoselective reduction of the resulting pyranones provides a complimentary approach to forming the required γ-lactone-fused benzopyran systems.

  10. Pseudomonas aeruginosa quorum-sensing molecule homoserine lactone modulates inflammatory signaling through PERK and eI-F2α.

    Science.gov (United States)

    Grabiner, Mark A; Fu, Zhu; Wu, Tara; Barry, Kevin C; Schwarzer, Christian; Machen, Terry E

    2014-08-01

    Pseudomonas aeruginosa secrete N-(3-oxododecanoyl)-homoserine lactone (HSL-C12) as a quorum-sensing molecule to regulate bacterial gene expression. Because HSL-C12 is membrane permeant, multiple cell types in P. aeruginosa-infected airways may be exposed to HSL-C12, especially adjacent to biofilms where local (HSL-C12) may be high. Previous reports showed that HSL-C12 causes both pro- and anti-inflammatory effects. To characterize HSL-C12's pro- and anti-inflammatory effects in host cells, we measured protein synthesis, NF-κB activation, and KC (mouse IL-8) and IL-6 mRNA and protein secretion in wild-type mouse embryonic fibroblasts (MEF). To test the role of the endoplasmic reticulum stress inducer, PERK we compared these responses in PERK(-/-) and PERK-corrected PERK(-/-) MEF. During 4-h treatments of wild-type MEF, HSL-C12 potentially activated NF-κB p65 by preventing the resynthesis of IκB and increased transcription of KC and IL-6 genes (quantitative PCR). HSL-C12 also inhibited secretion of KC and/or IL-6 into the media (ELISA) both in control conditions and also during stimulation by TNF-α. HSL-C12 also activated PERK (as shown by increased phosphorylation of eI-F2α) and inhibited protein synthesis (as measured by incorporation of [(35)S]methionine by MEF). Comparisons of PERK(-/-) and PERK-corrected MEF showed that HSL-C12's effects were explained in part by activation of PERK→phosphorylation of eI-F2α→inhibition of protein synthesis→reduced IκBα production→activation of NF-κB→increased transcription of the KC gene but reduced translation and secretion of KC. HSL-C12 may be an important modulator of early (up to 4 h) inflammatory signaling in P. aeruginosa infections.

  11. N-acylated alanine methyl esters (NAMEs) from Roseovarius tolerans, structural analogs of quorum-sensing autoinducers, N-acylhomoserine lactones.

    Science.gov (United States)

    Bruns, Hilke; Thiel, Verena; Voget, Sonja; Patzelt, Diana; Daniel, Rolf; Wagner-Döbler, Irene; Schulz, Stefan

    2013-09-01

    The Roseobacter clade is one of the most important bacteria group living in the ocean. Liquid cultures of Roseovarius tolerans EL 164 were investigated for the production of autoinducers such as N-acylhomoserine lactones (AHLs) and other secondary metabolites. The XAD extracts were analyzed by GC/MS. Two AHLs, Z7-C14 : 1-homoserine lactone (HSL) and C15 : 1-HSL, were identified. Additionally, the extract contained five compounds with molecular-ion peaks at m/z 104, 145, and 158, thus exhibiting mass spectra similar to those of AHLs with corresponding peaks at m/z 102, 143, and 156. Isolation of the main compound by column chromatography, NMR analysis, dimethyl disulfide derivatization for the determination of the location of the CC bond and finally synthesis of the compound with the proposed structure confirmed the compound to be (Z)-N-(hexadec-9-enoyl)alanine methyl ester. Four additional minor compounds were identified as C14 : 0-, C15 : 0-, C16 : 0-, and C17 : 1-N-acylated alanine methyl esters (NAMEs). All NAMEs have not been described from natural sources before. A BLASTp search showed the presence of AHL-producing luxI genes, but no homologous genes potentially responsible for the structurally closely related NAMEs were found. The involvement of the NAMEs in chemical communication processes of the bacteria is discussed. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

  12. Kinetic modeling of the time course of N-butyryl-homoserine lactone concentration during batch cultivations of Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Henkel, Marius; Schmidberger, Anke; Kühnert, Christian; Beuker, Janina; Bernard, Thomas; Schwartz, Thomas; Syldatk, Christoph; Hausmann, Rudolf

    2013-09-01

    Quorum sensing affects the regulation of more than 300 genes in Pseudomonas aeruginosa, influencing growth, biofilm formation, and the biosynthesis of several products. The quorum sensing regulation mechanisms are mostly described in a qualitative character. Particularly, in this study, the kinetics of N-butyryl-homoserine lactone (C4-HSL) and rhamnolipid formation in P. aeruginosa PAO1 were of interest. In this system, the expression of the rhamnolipid biosynthesis genes rhlAB is directly coupled to the C4-HSL concentration via the rhl system. Batch cultivations in a bioreactor with sunflower oil have been used for these investigations. 3-oxo-dodecanoyl-homoserine lactone (3o-C12-HSL) displayed a lipophilic character and accumulated in the hydrophobic phase. Degradation of C4-HSL has been found to occur in the aqueous supernatant of the culture by yet unknown extracellular mechanisms, and production was found to be proportional to biomass concentration rather than by autoinduction mechanisms. Rhamnolipid production rates, as determined experimentally, were shown to correlate linearly with the concentration of autoinducer C4-HSL. These findings were used to derive a simple model, wherein a putative, extracellular protein with C4-HSL degrading activity was assumed (putative C4-HSL acylase). The model is based on data for catalytic efficiency of HSL-acylases extracted from literature (k cat/K m), experimentally determined basal C4-HSL production rates (q C4 - HSL (basal)), and two fitted parameters which describe the formation of the putative acylase and is therefore comparatively simple.

  13. Visualization of N-acylhomoserine lactone-mediated cell-cell communication between bacteria colonizing the tomato rhizosphere

    DEFF Research Database (Denmark)

    Steidle, A.; Sigl, K.; Schuhegger, R.

    2001-01-01

    Given that a large proportion of the bacteria colonizing the roots of plants is capable of producing N-acyl-L-homoserine lactone (AHL) molecules, it appears likely that these bacterial pheromones may serve as signals for communication between cells of different species. In this study, we have...

  14. Pseudomonas aeruginosa quorum-sensing signaling molecule N-3-oxododecanoyl homoserine lactone induces matrix metalloproteinase 9 expression via the AP1 pathway in rat fibroblasts.

    Science.gov (United States)

    Nakagami, Gojiro; Minematsu, Takeo; Morohoshi, Tomohiro; Yamane, Takumi; Kanazawa, Toshiki; Huang, Lijuan; Asada, Mayumi; Nagase, Takashi; Ikeda, Shin-ichi; Ikeda, Tsukasa; Sanada, Hiromi

    2015-01-01

    Quorum sensing is a cell-to-cell communication mechanism, which is responsible for regulating a number of bacterial virulence factors and biofilm maturation and therefore plays an important role for establishing wound infection. Quorum-sensing signals may induce inflammation and predispose wounds to infection by Pseudomonas aeruginosa; however, the interaction has not been well investigated. We examined the effects of the P. aeruginosa las quorum-sensing signal, N-3-oxo-dodecanoyl homoserine lactone (3OC12-HSL), on matrix metalloproteinase (MMP) 9 expression in Rat-1 fibroblasts. 3OC12-HSL upregulated the expression of the MMP9 gene bearing an activator protein-1 (AP-1) binding site in the promoter region. We further investigated the mechanism underlying this effect. c-Fos gene expression increased rapidly after exposure to 3OC12-HSL, and nuclear translocation of c-Fos protein was observed; both effects were reduced by pretreatment with an AP-1 inhibitor. These results suggest that 3OC12-HSL can alter MMP9 gene expression in fibroblasts via the AP-1 signaling pathway.

  15. The quorum-sensing molecule N-3-oxododecanoyl homoserine lactone (3OC12-HSL) enhances the host defence by activating human polymorphonuclear neutrophils (PMN).

    Science.gov (United States)

    Wagner, Christof; Zimmermann, Sabine; Brenner-Weiss, Gerald; Hug, Friederike; Prior, Birgit; Obst, Ursula; Hänsch, Gertrud Maria

    2007-01-01

    The P. aeruginosa quorum-sensing molecule N-3-oxododecanoyl homoserine lactone (3OC12-HSL) interacts not only with bacteria, but also with mammalian cells, among others with those of the immune defence system. We focussed on the possible interaction of 3OC12-HSL with human polymorphonuclear neutrophils (PMN), because these cells are the first to enter an infected site. We found that 3OC12-HSL attracts PMN, and up-regulates expression of receptors known to be involved in host defence, including the adhesion proteins CD11b/CD18 and the immunoglobulin receptors CD16 and CD64. Furthermore, the uptake of bacteria (phagocytosis), which is crucial for an efficient defence against infection, was enhanced. Thus, recognising and responding to 3OC12-HSL not only attracts the PMN to the site of a developing biofilm, but also reinforces their defence mechanisms, and hence could be a means to control the infection in an early stage and to prevent biofilm formation.

  16. Infrared study of the bacterial autoinducer N-hexanoyl-homoserine lactone (C6-HSL) in the gas-phase, water, and octanol solutions.

    Science.gov (United States)

    Kim, Jiah; Kim, Seong Keun; Grégoire, Gilles; Manil, Bruno; Schermann, Jean Pierre

    2011-08-25

    The N-hexanoyl-homoserine lactone (C6-HSL) molecule has been investigated by means of infrared multiphoton dissociation (IRMPD) and Fourier-transform infrared spectroscopy (FT-IR) under different conditions in an attempt to mimic biological situations encountered in communication between bacteria for quorum sensing. The protonated molecular ion was studied in the gas-phase that corresponds to a solvent-free situation somewhat analogous to that encountered in the receptor. The simulation of the IRMPD spectrum of the isolated ion was then conducted by means of quantum chemistry calculations in vacuum. In the case of the neutral species, the FT-IR spectra were recorded in D(2)O, mimicking the cytosolic and extracellular media as well as in 1-octanol that is often used for simulation of cell membranes. The interpretation was conducted by considering a C6-HSL molecule in its endo or exo conformation hydrogen-bonded to, respectively, six D(2)O and four 1-octanol molecules. A satisfying agreement with the experimental FT-IR studies conducted in solution at room temperature was obtained as long as a continuum IEFPCM model was added to the explicit solvent environment.

  17. Solid‐Phase Synthesis and Biological Evaluation of N‐Dipeptido L‐Homoserine Lactones as Quorum Sensing Activators

    DEFF Research Database (Denmark)

    Hansen, Mette Reimert; Le Quement, Sebastian Thordal; Jakobsen, Tim Holm

    2014-01-01

    Bacteria use small signaling molecules to communicate in a process termed “quorum sensing” (QS), which enables the coordination of survival strategies, such as production of virulence factors and biofilm formation. In Gram‐negative bacteria, these signaling molecules are a series of N‐acylated L...... and released through an efficient acid‐mediated cyclative release mechanism. Subsequent screening for modulation of QS in Pseudomonas aeruginosa and E. coli identified six moderately strong activators. A follow‐up library designed from the preliminary derived structure–activity relationships was synthesized...

  18. The Pseudomonas aeruginosa quorum sensing signal molecule N-(3-oxododecanoyl) homoserine lactone enhances keratinocyte migration and induces Mmp13 gene expression in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Paes, Camila, E-mail: camilaquinetti@gmail.com [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nakagami, Gojiro, E-mail: gojiron-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Minematsu, Takeo, E-mail: tminematsu-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nagase, Takashi, E-mail: tnagase@fb3.so-net.ne.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Huang, Lijuan, E-mail: koureikenhlj@gmail.com [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sari, Yunita, E-mail: yunita-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Sanada, Hiromi, E-mail: hsanada-tky@umin.ac.jp [University of Tokyo, Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer An evidence of the positive effect of AHL on epithelialization process is provided. Black-Right-Pointing-Pointer AHL enhances keratinocyte's ability to migrate in an in vitro scratch wound model. Black-Right-Pointing-Pointer AHL induces the expression of Mmp13. Black-Right-Pointing-Pointer Topical application of AHL represents a possible strategy to treat chronic wounds. -- Abstract: Re-epithelialization is an essential step of wound healing involving three overlapping keratinocyte functions: migration, proliferation and differentiation. While quorum sensing (QS) is a cell density-dependent signaling system that enables bacteria to regulate the expression of certain genes, the QS molecule N-(3-oxododecanoyl) homoserine lactone (AHL) exerts effects also on mammalian cells in a process called inter-kingdom signaling. Recent studies have shown that AHL improves epithelialization in in vivo wound healing models but detailed understanding of the molecular and cellular mechanisms are needed. The present study focused on the AHL as a candidate reagent to improve wound healing through direct modulation of keratinocyte's activity in the re-epithelialization process. Results indicated that AHL enhances the keratinocyte's ability to migrate in an in vitro scratch wound healing model probably due to the high Mmp13 gene expression analysis after AHL treatment that was revealed by real-time RT-PCR. Inhibition of activator protein 1 (AP-1) signaling pathway completely prevented the migration of keratinocytes, and also resulted in a diminished Mmp13 gene expression, suggesting that AP-1 might be essential in the AHL-induced migration. Taken together, these results imply that AHL is a promising candidate molecule to improve re-epithelialization through the induction of migration of keratinocytes. Further investigation is needed to clarify the mechanism of action and molecular pathway of AHL on the keratinocyte migration

  19. Phenotypic and genotypic characterisation of Burkholderia cenocepacia J2315 mutants affected in homoserine lactone and diffusible signal factor-based quorum sensing systems suggests interplay between both types of systems.

    Directory of Open Access Journals (Sweden)

    Claudia Udine

    Full Text Available Many putative virulence factors of Burkholderia cenocepacia are controlled by various quorum sensing (QS circuits. These QS systems either use N-acyl homoserine lactones (AHL or cis-2-dodecenoic acid ("Burkholderia diffusible signal factor", BDSF as signalling molecules. Previous work suggested that there is little cross-talk between both types of systems. We constructed mutants in B. cenocepacia strain J2315, in which genes encoding CepI (BCAM1870, CciI (BCAM0239a and the BDSF synthase (BCAM0581 were inactivated, and also constructed double (ΔcepIΔBCAM0581, ΔcciIΔBCAM0581 and ΔcepIΔcciI mutants and a triple (ΔcepIΔcciIΔBCAM0581 mutant. Subsequently we investigated phenotypic properties (antibiotic susceptibility, biofilm formation, production of AHL and BDSF, protease activity and virulence in Caenorhabditis elegans and measured gene expression in these mutants, and this in the presence and absence of added BDSF, AHL or both. The triple mutant was significantly more affected in biofilm formation, antimicrobial susceptibility, virulence in C. elegans, and protease production than either the single or double mutants. The ΔBCAM0581 mutant and the ΔcepIΔBCAM0581 and ΔcciIΔBCAM0581 double mutants produced significantly less AHL compared to the WT strain and the ΔcepI and ΔcciI single mutant, respectively. The expression of cepI and cciI in ΔBCAM0581, was approximately 3-fold and 7-fold (p<0.05 lower than in the WT, respectively. The observed differences in AHL production, expression of cepI and cciI and QS-controlled phenotypes in the ΔBCAM0581 mutant could (at least partially be restored by addition of BDSF. Our data suggest that, in B. cenocepacia J2315, AHL and BDSF-based QS systems co-regulate the same set of genes, regulate different sets of genes that are involved in the same phenotypes and/or that the BDSF system controls the AHL-based QS system. As the expression of the gene encoding the C6-HSL synthase CciI (and to a

  20. Profiling of acylated homoserine lactones of Vibrio anguillarum in vitro and in vivo: influence of growth conditions and serotype

    DEFF Research Database (Denmark)

    Buchholtz, Chrstiane; Nielsen, Kristian Fog; L. Milton, Debra

    2006-01-01

    and biofilm formation. Using both thin layer chromatography and HPLC-high resolution mass spectrometry (HPLC-HRMS), we demonstrate in this study that the same types of AHLs are produced by many serotypes of V. anguillarum and that altering in vitro growth conditions (salinity, temperature and iron...... tissues. Hence, the balance between the QS systems may be different during infection compared to in vitro cultures. For future studies of QS systems and the possible specific interference with expression of virulence factors, in vitro cultures should be optimised to reflect the in vivo situation.layer...... chromatography and HPLC-high resolution mass spectrometry (HPLC-HRMS), we demonstrate in this study that the same types of AHLs are produced by many serotypes of V. anguillarum and that altering in vitro growth conditions (salinity, temperature and iron concentration) has little influence on the AHL...

  1. Synthesis and biological evaluation of triazole-containing N-acyl homoserine lactones as quorum sensing modulators

    DEFF Research Database (Denmark)

    Stacy, Danielle M.; Le Quement, Sebastian T.; Hansen, Casper L.

    2013-01-01

    . These compounds were evaluated for their ability to activate or inhibit two QS receptors from two prevalent pathogens – LasR from Pseudomonas aeruginosa and AbaR from Acinetobacter baumannii – using bacterial reporter strains. Several triazole derivatives were identified that were capable of strongly modulating...

  2. Quorum Sensing Inhibitors from the Sea Discovered Using Bacterial N-acyl-homoserine Lactone-Based Biosensors

    Directory of Open Access Journals (Sweden)

    Kumar Saurav

    2017-02-01

    Full Text Available Marine natural products with antibiotic activity have been a rich source of drug discovery; however, the emergence of antibiotic-resistant bacterial strains has turned attention towards the discovery of alternative innovative strategies to combat pathogens. In many pathogenic bacteria, the expression of virulence factors is under the regulation of quorum sensing (QS. QS inhibitors (QSIs present a promising alternative or potential synergistic treatment since they disrupt the signaling pathway used for intra- and interspecies coordination of expression of virulence factors. This review covers the set of molecules showing QSI activity that were isolated from marine organisms, including plants (algae, animals (sponges, cnidarians, and bryozoans, and microorganisms (bacteria, fungi, and cyanobacteria. The compounds found and the methods used for their isolation are the emphasis of this review.

  3. Production of acylated homoserine lactones by different serotypes of Vibrio anguillarum both in culture and during infection of rainbow trout

    DEFF Research Database (Denmark)

    Buch, Christiane; Sigh, Jens; Nielsen, John

    2003-01-01

    . The production rate of the presumed 3-oxo-C10-HSL followed the growth rate of V. anguillarum whereas the production rate of a small AHL (Rf value of 0.74) increased faster than the growth rate of V. anguillarum indicating autoinduction. AHLs were produced by all serotypes (O1 to O10) and by non-typable strains...... determining oxidative burst of fish macrophages exposed to 3-oxo-C10-HSL. No activation or suppression of the superoxide anion production in the head kidney macrophages was seen when treated with the AHL compound in concentrations of 1 nM-10 μM. Our data show that AHLs are produced by almost all V....... anguillarum strains and that no clear pattern relating AHL production to disease or virulence appear....

  4. Quorum Sensing Inhibitors from the Sea Discovered Using Bacterial N-acyl-homoserine Lactone-Based Biosensors

    Science.gov (United States)

    Saurav, Kumar; Costantino, Valeria; Venturi, Vittorio; Steindler, Laura

    2017-01-01

    Marine natural products with antibiotic activity have been a rich source of drug discovery; however, the emergence of antibiotic-resistant bacterial strains has turned attention towards the discovery of alternative innovative strategies to combat pathogens. In many pathogenic bacteria, the expression of virulence factors is under the regulation of quorum sensing (QS). QS inhibitors (QSIs) present a promising alternative or potential synergistic treatment since they disrupt the signaling pathway used for intra- and interspecies coordination of expression of virulence factors. This review covers the set of molecules showing QSI activity that were isolated from marine organisms, including plants (algae), animals (sponges, cnidarians, and bryozoans), and microorganisms (bacteria, fungi, and cyanobacteria). The compounds found and the methods used for their isolation are the emphasis of this review. PMID:28241461

  5. Pseudomonas aeruginosa quorum-sensing molecule N-(3-oxododecanoyl) homoserine lactone attenuates lipopolysaccharide-induced inflammation by activating the unfolded protein response.

    Science.gov (United States)

    Zhang, Jiangguo; Gong, Fengyun; Li, Ling; Zhao, Manzhi; Song, Jianxin

    2014-03-01

    N-3-oxododecanoyl homoserine lactone (3-oxo-C12-HSL), a quorum-sensing signal molecule produced by Pseudomonas aeruginosa (P. aeruginosa), is involved in the expression of bacterial virulence factors and in the modulation of host immune responses by directly disrupting nuclear factor-κB (NF-κB) signaling and inducing cell apoptosis. The unfolded protein response (UPR) triggered by endoplasmic reticulum (ER) stress may suppress inflammatory responses in the later phase by blocking NF-κB activation. It was recently demonstrated that 3-oxo-C12-HSL may induce UPR in human aortic endothelial cells (HAECs). Therefore, 3-oxo-C12-HSL may also inhibit NF-κB activation and suppress inflammatory responses by activating UPR. However, the possible underlying mechanism has not been fully elucidated. Accordingly, we investigated the effects of 3-oxo-C12-HSL on cellular viability, UPR activation, lipopolysaccharide (LPS)-induced NF-κB activation and inflammatory response in the RAW264.7 mouse macrophage cell line. Treatment with 6.25 μM 3-oxo-C12-HSL was not found to affect the viability of RAW264.7 cells. However, pretreating RAW264.7 cells with 6.25 μM 3-oxo-C12-HSL effectively triggered UPR and increased the expression of UPR target genes, such as CCAAT/enhancer-binding protein β (C/EBP β) and CCAAT/enhancer-binding protein-homologous protein (CHOP). The expression of C/EBP β and CHOP was found to be inversely correlated with LPS-induced NF-κB activation. 3-Oxo-C12-HSL pretreatment was also shown to inhibit LPS-stimulated proinflammatory cytokine production. Hence, 3-oxo-C12-HSL may attenuate LPS-induced inflammation via UPR-mediated NF-κB inhibition without affecting cell viability. This may be another mechanism through which P. aeruginosa evades the host immune system and maintains a persistent infection.

  6. [Non-species-specific effects of unacylated homoserine lactone and hexylresorcinol, low molecular weight autoregulators, on the growth and development of bacteria].

    Science.gov (United States)

    Muliukin, A L; Filippova, S N; Kozlova, A N; Surgucheva, N A; Bogdanova, T I; Tsaplina, I A; El'-Registan, G I

    2006-01-01

    We conducted a comparative study of the effects of alpha-amino-gamma-butyrolactone, the common structural element of extracellular microbial regulators of the homoserine lactone (HSL) group, and of 4-n-hexylresorcinol, an autoregulator of the alkylhydroxybenzene (AHB) group, on the growth and development of gram-positive and gram-negative bacteria. We revealed non-species-specific effects of HSL and AHB and characterized their concentration dependencies. The addition of 10(-5)-10(-3) M HSL or 10(-5)-10(-4) M AHB during the exponential growth phase of the cultures grown on balanced media resulted in cell division arrest and accelerated the transition to the stationary phase that culminated in endospore formation in Bacillus cereus, Alicyclobacillus tolerans, and Sulfobacillus thermosulfidooxidans. When bacilli grew under the cultivation conditions that resulted in a low-zero spore percentage, 10(-4)-10(-3) M HSL cancelled the inhibition of spore formation. In the gram-negative bacteria Pseudomonas aurantiaca and Azotobacter vinelandii, AHB at concentrations of 10(-4) to (1.5-2.5) 10(-4) M induced the formation of dormant cells. Studies with the actinobacterium Streptomyces avermitilis revealed that the HSL effect varied depending on the age of the test cultures. The addition of 10(-4) M HSL during the lag phase of a submerged streptomycete culture accelerated its transition to the stationary phase and induced the formation of endospores, the dormant cells that are regarded as alternatives to exospores (conidia). If HSL (3.64 and 4.55 mg per 1cm2 disc) was locally added to a surface S. avermitilis culture, the growing mycelium formed rings that differed in their density, in the extent of the development of aerial mycelium, and in the presence/absence of exospores. Ring-shaped growth of streptomycete mycelia was also induced by 0.075-0.75 mg of AHB; however, unlike HSL, AHB repressed exospore formation. The data on non-species-specific effects of HSL and AHB suggest

  7. 3-羰基辛酰基高丝氨酸内酯诱导拟南芥根细胞Ca2+内流%N-3-oxo-Octanoyl-Homoserine Lactone Induces Intracellular Ca2+ Elevation in Arabidopsis Root Cells

    Institute of Scientific and Technical Information of China (English)

    张哲; 张霞; 边子睿; 宋水山

    2011-01-01

    Af-acyl-L-homoserine lactones (AHLs) are the signal molecules which mediate the quorum-sensing (QS) in Gram-negative bacteria. In recent years, the accumulating evidence indicates that AHLs are able to regulate the growth, development and defense response of plants. However, the mechanisms by which plant responses to bacterial QS signal molecule is little known. In this study, the change of cytosolic free Ca2+ concentration ([Ca2+]cyt) and the activities of calcium channel in Arabidopsis thaliana root cells induced by N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL) were monitored by both microplate luminometer and the whole-cell patch clamping. A transient elevation in [Ca2+]cyt was observed upon the treatment with 3OQ-HSL in the root cells of Arabidopsis expressing the Ca2+ bioluminescent indicator aequorin. The elevation in [Ca2+]cyt induced by 3OC8-HSL treatment was completely blocked by pretreatment with EGTA, verapamil and LaCl3, but was unaffected by LiCl pretreatment. Furthermore, a hyperpolarization-activated calcium permeable channel was recorded in plasma membrane of Arabidopsis root tip protoplast. The Ca2+ current intensity increased remarkably after 3OC8-HSL treatment. The results reveal that 3OC8-HSL can induce the generation of Ca2+ signal in Arabidopsis root cells and the cytosolic free Ca2+ increase induced by 3OC8-HSL comes mainly from the extracellular space, illuminating that Ca2+ signaling participates in the plant cells sensing to bacterial QS signals.%N-酰基高丝氨酸内酯(AHLs)是革兰氏阴性细菌群体感应系统(QS)中的胞间通讯信号分子.近年的研究表明AHLs可以调控植物生长发育及防卫反应,但其调控机制尚不清楚.本研究以拟南芥为材料,采用3-羰基辛酰基高丝氨酸内酯(3OC8-HSL)处理转水母发光蛋白基因的拟南芥幼根细胞,利用冷光仪检测3OC8-HSL对拟南芥根细胞中胞质游离Ca2+浓度([Ca2+]cyt)变化的影响,同时采用Ca2+专一性螯合剂EGTA和Ca2+

  8. In Planta Biocontrol of Pectobacterium atrosepticum by Rhodococcus erythropolis Involves Silencing of Pathogen Communication by the Rhodococcal Gamma-Lactone Catabolic Pathway.

    Science.gov (United States)

    Barbey, Corinne; Crépin, Alexandre; Bergeau, Dorian; Ouchiha, Asma; Mijouin, Lily; Taupin, Laure; Orange, Nicole; Feuilloley, Marc; Dufour, Alain; Burini, Jean-François; Latour, Xavier

    2013-01-01

    The virulence of numerous Gram-negative bacteria is under the control of a quorum sensing process based on synthesis and perception of N-acyl homoserine lactones. Rhodococcus erythropolis, a Gram-positive bacterium, has recently been proposed as a biocontrol agent for plant protection against soft-rot bacteria, including Pectobacterium. Here, we show that the γ-lactone catabolic pathway of R. erythropolis disrupts Pectobacterium communication and prevents plant soft-rot. We report the first characterization and demonstration of N-acyl homoserine lactone quenching in planta. In particular, we describe the transcription of the R. erythropolis lactonase gene, encoding the key enzyme of this pathway, and the subsequent lactone breakdown. The role of this catabolic pathway in biocontrol activity was confirmed by deletion of the lactonase gene from R. erythropolis and also its heterologous expression in Escherichia coli. The γ-lactone catabolic pathway is induced by pathogen communication rather than by pathogen invasion. This is thus a novel and unusual biocontrol pathway, differing from those previously described as protecting plants from phytopathogens. These findings also suggest the existence of an additional pathway contributing to plant protection.

  9. In Planta Biocontrol of Pectobacterium atrosepticum by Rhodococcus erythropolis Involves Silencing of Pathogen Communication by the Rhodococcal Gamma-Lactone Catabolic Pathway.

    Directory of Open Access Journals (Sweden)

    Corinne Barbey

    Full Text Available The virulence of numerous Gram-negative bacteria is under the control of a quorum sensing process based on synthesis and perception of N-acyl homoserine lactones. Rhodococcus erythropolis, a Gram-positive bacterium, has recently been proposed as a biocontrol agent for plant protection against soft-rot bacteria, including Pectobacterium. Here, we show that the γ-lactone catabolic pathway of R. erythropolis disrupts Pectobacterium communication and prevents plant soft-rot. We report the first characterization and demonstration of N-acyl homoserine lactone quenching in planta. In particular, we describe the transcription of the R. erythropolis lactonase gene, encoding the key enzyme of this pathway, and the subsequent lactone breakdown. The role of this catabolic pathway in biocontrol activity was confirmed by deletion of the lactonase gene from R. erythropolis and also its heterologous expression in Escherichia coli. The γ-lactone catabolic pathway is induced by pathogen communication rather than by pathogen invasion. This is thus a novel and unusual biocontrol pathway, differing from those previously described as protecting plants from phytopathogens. These findings also suggest the existence of an additional pathway contributing to plant protection.

  10. Binding events of (S )-N -(3-oxo-octanoyl)-homoserine lactone with agrobacterium tumefaciens mutant cells studied by saturation transfer difference NMR

    Energy Technology Data Exchange (ETDEWEB)

    Cabeca, Luis Fernando; Pomini, Armando Mateus; Cruz, Pedro Luiz R.; Marsaioli, Anita J. [University of Campinas (UNICAMP), SP (Brazil). Chemistry Inst.

    2011-07-01

    Quorum-sensing is a widely studied communication phenomenon in bacteria, which involves the production and detection of signaling substances in relation with cell density and colony behavior. Herein, the membrane binding interactions of the signal (S)-N-(3-oxo-octanoyl)-HSL with A. tumefaciens NTL4(pZLR4) cells were studied using saturation transfer difference NMR spectroscopy (STD-NMR). The substance epitope map was obtained showing that the hydrophobic acyl chain is the most important interacting site for the signal and the cell membrane. Results were interpreted upon comparisons with a simpler system, using liposomes as membrane models. Some insights on the use of b-cyclodextrin as acyl-HSL carrier were also provided. (author)

  11. Tasting Pseudomonas aeruginosa biofilms.Human neutrophils express the bitter receptor T2R38 as sensor for the quorum sensing molecule N-(3-oxododecanoyl-L-homoserine lactone

    Directory of Open Access Journals (Sweden)

    Susanne eMaurer

    2015-07-01

    Full Text Available Bacteria communicate with each other via specialized signalling molecules, known as quorum sensing molecules or autoinducers. The Pseudomonas aeruginosa-derived quorum sensing molecule N-(3-oxododecanoyl-L-homoserine lactone (AHL-12, however, also activates mammalian cells. As shown previously, AHL-12 induced chemotaxis, up-regulated CD11b expression, and enhanced phagocytosis of polymorphonuclear neutrophils (PMN. Circumstantial evidence concurred with a receptor for AHL-12, which so far has been elusive. We investigated the bitter receptor T2R38 as a potential candidate. Although identified as a taste receptor, cells outside the gustatory system express T2R38, for example epithelial cells in the lung. We now detected T2R38 in peripheral blood neutrophils, monocytes and lymphocytes on the cell membrane, but also intracellular. In neutrophils, T2R38 was located in vesicles with characteristics of lipid droplets, and super-resolution microscopy showed a co-localisation with the lipid droplet membrane. Neutrophils take up AHL-12, and it co-localized with T2R38 as seen by laser scan microscopy. Binding of AHL-12 to T2R28 was confirmed by pull-down assays using biotin-coupled AHL-12 as bait. A commercially available antibody to T2R38 inhibited binding of AHL-12 to neutrophils, and this antibody by itself stimulated neutrophils, similarly to AHL-12. In conclusion, our data provide evidence for expression of functional T2R38 on neutrophils, and are compatible with the notion that T2R38 is the receptor for AHL-12 on neutrophils.

  12. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules.

    Science.gov (United States)

    Romano, Ariel A; Hahn, Tobias; Davis, Nicole; Lowery, Colin A; Struss, Anjali K; Janda, Kim D; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

    2012-02-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C(12)-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding.

  13. Influence of food preservation parameters and associated microbiota on production rate, profile and stability of acylated homoserine lactones from food-derived Enterobacteriaceae

    DEFF Research Database (Denmark)

    Flodgaard, Lars; Christensen, Allan Beck; Molin, Søren

    2003-01-01

    by Gram-negative bacteria participating in spoilage. As part of our investigation of the role of AHLs in food quality, we studied the AHL production in two Enterobacteriaceae isolated from cold-smoked salmon under growth conditions typical of those found in cold-smoked salmon. We tested the influence...

  14. The absence of the N-acyl-homoserine-lactone autoinducer synthase genes tral and ngrl increases the copy number of the symbiotic plasmid in sinorhizobium fredii NGR234

    Science.gov (United States)

    Plant-released flavonoids induce the transcription of symbiotic genes in rhizobia and one of the first bacterial responses is the synthesis of so called Nod factors. They are responsible for the initial root hair curling during onset of root nodule development. This signal exchange is believed to be...

  15. N-Acyl-L-homoserine lactone autoinducers control production of an extracellular lipopeptide biosurfactant required for swarming motility of Serratia liquefaciens MG1

    DEFF Research Database (Denmark)

    Lindum, Peter Wurtz; Anthoni, U; Christophersen, Carsten

    1998-01-01

    A nonswarming Serratia liquefaciens mutant deficient in serrawettin W2 production was constructed by transposon mutagenesis. Sequence homology indicated that insertion had occurred in gene swrA, which encodes a putative peptide synthetase. Expression of swrA is controlled by quorum sensing....

  16. Magnetic molecularly imprinted polymer nanoparticles based electrochemical sensor for the measurement of Gram-negative bacterial quorum signaling molecules (N-acyl-homoserine-lactones).

    Science.gov (United States)

    Jiang, Hui; Jiang, Donglei; Shao, Jingdong; Sun, Xiulan

    2016-01-15

    We have developed a novel and economical electrochemical sensor to measure Gram-negative bacterial quorum signaling molecules (AHLs) using magnetic nanoparticles and molecularly imprinted polymer (MIP) technology. Magnetic molecularly imprinted polymers (MMIPs) capable of selectively absorbing AHLs were successfully synthesized by surface polymerization. The particles were deposited onto a magnetic carbon paste electrode (MGCE) surface, and characterized by electrochemical measurements. Differential Pulse Voltammetry (DPV) was utilized to record the oxidative current signal that is characteristic of AHL. The detection limit of this assay was determined to be 8×10(-10)molL(-1) with a linear detection range of 2.5×10(-9)molL(-1) to 1.0×10(-7)molL(-1). This Fe3O4@SiO2-MIP-based electrochemical sensor is a valuable new tool that allows quantitative measurement of Gram-negative bacterial quorum signaling molecules. It has potential applications in the fields of clinical diagnosis or food analysis with real-time detection capability, high specificity, excellent reproducibility, and good stability.

  17. Triazole-containing N-acyl homoserine lactones targeting the quorum sensing system in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Hansen, Mette Reimert; Jakobsen, Tim H.; Bang, Claus Gunnar;

    2015-01-01

    In an attempt to devise new antimicrobial treatments for biofilm infections, the bacterial cell-cell communication system termed quorum sensing has emerged as an attractive target. It has proven possible to intercept the communication system by synthetic non-native ligands and thereby lower the p...

  18. Rhodococcus erythropolis and Its γ-Lactone Catabolic Pathway: An Unusual Biocontrol System That Disrupts Pathogen Quorum Sensing Communication

    Directory of Open Access Journals (Sweden)

    Xavier Latour

    2013-12-01

    Full Text Available Rhodococcus erythropolis is an environmental Gram-positive Actinobacterium with a versatile metabolism involved in various bioconversions and degradations. Rhodococci are best known for their great potential in numerous decontamination and industrial processes. However, they can also prevent plant disease by disrupting quorum sensing-based communication of Gram-negative soft-rot bacteria, by degrading N-acyl-homoserine lactone signaling molecules. Such biocontrol activity results partly from the action of the γ-lactone catabolic pathway. This pathway is responsible for cleaving the lactone bond of a wide range of compounds comprising a γ-butyrolactone ring coupled to an alkyl or acyl chain. The aliphatic products of this hydrolysis are then activated and enter fatty acid metabolism. This short pathway is controlled by the presence of the γ-lactone, presumably sensed by a TetR-like transcriptional regulator, rather than the presence of the pathogen or the plant-host in the environment of the Rhodococci. Both the density and biocontrol activity of R. erythropolis may be boosted in crop systems. Treatment with a cheap γ-lactone stimulator, for example, the food flavoring γ-caprolactone, induces the activity in the biocontrol agent, R. erythropolis, of the pathway degrading signaling molecules; such treatments thus promote plant protection.

  19. Control of acetic acid fermentation by quorum sensing via N-acylhomoserine lactones in Gluconacetobacter intermedius.

    Science.gov (United States)

    Iida, Aya; Ohnishi, Yasuo; Horinouchi, Sueharu

    2008-04-01

    A number of gram-negative bacteria regulate gene expression in a cell density-dependent manner by quorum sensing via N-acylhomoserine lactones (AHLs). Gluconacetobacter intermedius NCI1051, a gram-negative acetic acid bacterium, produces three different AHLs, N-decanoyl-l-homoserine lactone, N-dodecanoyl-L-homoserine lactone, and an N-dodecanoyl-L-homoserine lactone with a single unsaturated bond in its acyl chain, as determined by liquid chromatography-tandem mass spectrometry. Two genes encoding an AHL synthase and a cognate regulator were cloned from strain NCI1051 and designated ginI and ginR, respectively. Disruption of ginI or ginR abolished AHL production, indicating that NCI1051 contains a single set of quorum-sensing genes. Transcriptional analysis showed that ginI is activated by GinR, which is consistent with the finding that there is an inverted repeat whose nucleotide sequence is similar to the sequence bound by members of the LuxR family at position -45 with respect to the transcriptional start site of ginI. A single gene, designated ginA, located just downstream of ginI is transcribed by read-through from the GinR-inducible ginI promoter. A ginA mutant, as well as the ginI and ginR mutants, grew more rapidly in medium containing 2% (vol/vol) ethanol and accumulated acetic acid at a higher rate with a greater final yield than parental strain NCI1051. In addition, these mutants produced larger amounts of gluconic acid than the parental strain. These data demonstrate that the GinI/GinR quorum-sensing system in G. intermedius controls the expression of ginA, which in turn represses oxidative fermentation, including acetic acid and gluconic acid fermentation.

  20. Crystallization and rhenium MAD phasing of the acyl-homoserinelactone synthase EsaI

    Energy Technology Data Exchange (ETDEWEB)

    Watson, W.T.; Murphy IV, Frank V.; Gould, Ty A.; Jambeck, Per; Val, Dale L.; Cronan, Jr., John E.; Beck von Bodman, Susan; Churchill, Mair E.A. (UIUC); (Colorado); (Connecticut)

    2009-04-22

    Acyl-homoserine-L-lactones (AHLs) are diffusible chemical signals that are required for virulence of many Gram-negative bacteria. AHLs are produced by AHL synthases from two substrates, S-adenosyl-L-methionine and acyl-acyl carrier protein. The AHL synthase EsaI, which is homologous to the AHL synthases from other pathogenic bacterial species, has been crystallized in the primitive tetragonal space group P4{sub 3}, with unit-cell parameters a = b = 66.40, c = 47.33 {angstrom}. The structure was solved by multiple-wavelength anomalous diffraction with a novel use of the rhenium anomalous signal. The rhenium-containing structure has been refined to a resolution of 2.5 {angstrom} and the perrhenate ion binding sites and liganding residues have been identified.

  1. Control of Acetic Acid Fermentation by Quorum Sensing via N-Acylhomoserine Lactones in Gluconacetobacter intermedius▿ †

    Science.gov (United States)

    Iida, Aya; Ohnishi, Yasuo; Horinouchi, Sueharu

    2008-01-01

    A number of gram-negative bacteria regulate gene expression in a cell density-dependent manner by quorum sensing via N-acylhomoserine lactones (AHLs). Gluconacetobacter intermedius NCI1051, a gram-negative acetic acid bacterium, produces three different AHLs, N-decanoyl-l-homoserine lactone, N-dodecanoyl-l-homoserine lactone, and an N-dodecanoyl-l-homoserine lactone with a single unsaturated bond in its acyl chain, as determined by liquid chromatography-tandem mass spectrometry. Two genes encoding an AHL synthase and a cognate regulator were cloned from strain NCI1051 and designated ginI and ginR, respectively. Disruption of ginI or ginR abolished AHL production, indicating that NCI1051 contains a single set of quorum-sensing genes. Transcriptional analysis showed that ginI is activated by GinR, which is consistent with the finding that there is an inverted repeat whose nucleotide sequence is similar to the sequence bound by members of the LuxR family at position −45 with respect to the transcriptional start site of ginI. A single gene, designated ginA, located just downstream of ginI is transcribed by read-through from the GinR-inducible ginI promoter. A ginA mutant, as well as the ginI and ginR mutants, grew more rapidly in medium containing 2% (vol/vol) ethanol and accumulated acetic acid at a higher rate with a greater final yield than parental strain NCI1051. In addition, these mutants produced larger amounts of gluconic acid than the parental strain. These data demonstrate that the GinI/GinR quorum-sensing system in G. intermedius controls the expression of ginA, which in turn represses oxidative fermentation, including acetic acid and gluconic acid fermentation. PMID:18245283

  2. Remote Stereoinduction in the Acylation of Fully-Substituted Enolates: Tandem Reformatsky/Quaternary Claisen Condensations of Silyl Glyoxylates and β-Lactones

    Science.gov (United States)

    Greszler, Stephen N.; Malinowski, Justin T.

    2010-01-01

    Reformatsky reagents react sequentially with silyl glyoxylates and β-lactones to give highly functionalized Claisen condensation products. A heretofore undocumented instance of stereochemical 1,4-induction results in efficient transmission of β-lactone stereochemistry to the emerging fully-substituted stereocenter. Second-stage transformations reveal that the five heteroatom-containing functionalities embedded within the products are entirely chemo-differentiated, a circumstance that permits rapid assembly of the leustroducsin B core substructure. PMID:21087044

  3. Unusual Multiple Production of N-Acylhomoserine Lactones a by Burkholderia sp. Strain C10B Isolated from Dentine Caries

    Directory of Open Access Journals (Sweden)

    Share Yuan Goh

    2014-05-01

    Full Text Available Bacteria realize the ability to communicate by production of quorum sensing (QS molecules called autoinducers, which regulate the physiological activities in their ecological niches. The oral cavity could be a potential area for the presence of QS bacteria. In this study, we report the isolation of a QS bacterial isolate C10B from dentine caries. Preliminary screening using Chromobacterium violaceum CV026 biosensor showed that isolate C10B was able to produce N-acylhomoserine lactones (AHLs. This bacterium was further identified as a member of Burkholderia, an opportunistic pathogen. The isolated Burkholderia sp. was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL, N-octanoyl-L-homoserine lactone (C8-HSL, N-decanoyl-L-homoserine lactone (C10-HSL and N-dodecanoyl-L-homoserine lactone (C12-HSL.

  4. Effects of AHLs(N-hexanoyl-DL-homoserine lactone, C6-HSL)on growth and antioxidant defense system of Chlorella vulgaris%AHLs信号分子对小球藻生长及抗氧化酶系统的影响

    Institute of Scientific and Technical Information of China (English)

    毕相东; 周文礼; 邢克智; 唐学玺

    2012-01-01

    The effects of AHLs (N-hexanoyl-DL-homoserine ]actone,C6-HSL) on growth and antioxidani defense system of Chlorella vulgaris were studied in present study. The results showed that that low concentrations of C6-HSL (50,190 and 200 nmol/L) could increase the relative growth rate of C. Vulgaris obviously at 8 h (P < 0. 05). The higher concentrations of C6-HSL ( ≥400 nmol/L) could decrease the relative growth rate of C. Vulgaris obviously (P <0. 05) ,and exhibit the high concenrtration-dependent inhibition effects. 50 nmol/L C6-HSL could activate the defense response of C. Vulgaris in a short time (4 h),intreasft activities of SOD,POD, CAT and GPX of C. Vulgaris obviously (P <0.05) ,and decrease MDA content significantly (P <0. 05). Compared to low concentrations , the antioxidative enzymes of C. Vulgaris were increased to a peak then decreased, and the MDA content of C. Vulgaris were increased significantly 0 to 24 h exposure to 400 nmol/L C6-HSL (P<0.05).%以小球藻(Chlorella vulgaris)为试验材料,研究AHLs信号分子(N-hexanoyl-DL-homoserine lactone,C6-HSL)对小球藻生长及抗氧化酶系统的影响.结果表明:C6-HSL对小球藻生长的影响表现为低浓度促进而高浓度抑制的效应.低浓度C6-HSL(50、100及200 nmol/L)8 h时即可显著提高小球藻的相对生长率(P<0.05),高浓度C6-HSL(≥400 nmol/L)24 h时均可显著降低小球藻的相对生长率(P<0.05),且表现出较强的浓度依赖性抑制作用.50 nmol/(1)C6-HSL即可在4h时激活藻细胞防御性反应,显著提高SOD、POD、CAT及GPX的活性(P<0.05),同时显著降低MDA的含量(P<0.05);与低浓度组相比,400 nmol/L C6-HSL作用下,藻细胞抗氧化酶活性均经历先升高后降低的过程,24 h内藻细MDA含量显著升高(P<0.05).

  5. Quorum sensing and Chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of N-acylhomoserine lactones.

    Science.gov (United States)

    McClean, K H; Winson, M K; Fish, L; Taylor, A; Chhabra, S R; Camara, M; Daykin, M; Lamb, J H; Swift, S; Bycroft, B W; Stewart, G S; Williams, P

    1997-12-01

    Quorum sensing relies upon the interaction of a diffusible signal molecule with a transcriptional activator protein to couple gene expression with cell population density. In Gram-negative bacteria, such signal molecules are usually N-acylhomoserine lactones (AHLs) which differ in the structure of their N-acyl side chains. Chromobacterium violaceum, a Gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigment violacein. Previously the authors described a violacein-negative, mini-Tn5 mutant of C. violaceum (CV026) in which pigment production can be restored by incubation with supernatants from the wild-type strain. To develop this mutant as a general biosensor for AHLs, the natural C. violaceum AHL molecule was first chemically characterized. By using solvent extraction, HPLC and mass spectrometry, a single AHL, N-hexanoyl-L-homoserine lactone (HHL), was identified in wild-type C. violaceum culture supernatants which was absent from CV026. Since the production of violacein constitutes a simple assay for the detection of AHLs, we explored the ability of CV026 to respond to a series of synthetic AHL and N-acylhomocysteine thiolactone (AHT) analogues. In CV026, violacein is inducible by all the AHL and AHT compounds evaluated with N-acyl side chains from C4 to C8 in length, with varying degrees of sensitivity. Although AHL compounds with N-acyl side chains from C10 to C14 are unable to induce violacein production, if an activating AHL (e.g. HHL) is incorporated into the agar, these long-chain AHLs can be detected by their ability to inhibit violacein production. The versatility of CV026 in facilitating detection of AHL mixtures extracted from culture supernatants and separated by thin-layer chromatography is also demonstrated. These simple bioassays employing CV026 thus greatly extend the ability to detect a wide spectrum of AHL signal molecules.

  6. Modelled microgravity cultivation modulates N-acylhomoserine lactone production in Rhodospirillum rubrum S1H independently of cell density.

    Science.gov (United States)

    Mastroleo, Felice; Van Houdt, Rob; Atkinson, Steve; Mergeay, Max; Hendrickx, Larissa; Wattiez, Ruddy; Leys, Natalie

    2013-12-01

    The photosynthetic alphaproteobacterium Rhodospirillum rubrum S1H is part of the Micro-Ecological Life Support System Alternative (MELiSSA) project that is aiming to develop a closed life support system for oxygen, water and food production to support human life in space in forthcoming long-term space exploration missions. In the present study, R. rubrum S1H was cultured in a rotating wall vessel (RWV), simulating partial microgravity conditions on Earth. The bacterium showed a significant response to cultivation in simulated microgravity at the transcriptomic, proteomic and metabolic levels. In simulated microgravity conditions three N-acyl-l-homoserine lactones (C10-HSL, C12-HSL and 3-OH-C14-HSL) were detected in concentrations that were twice those detected under normal gravity, while no differences in cell density was detected. In addition, R. rubrum cultivated in modelled microgravity showed higher pigmentation than the normal gravity control, without change in culture oxygenation. When compared to randomized microgravity cultivation using a random positioning machine, significant overlap for the top differentially expressed genes and proteins was observed. Cultivation in this new artificial environment of simulated microgravity showed new properties of this well-known bacterium, including its first, to our knowledge, complete quorum-sensing-related N-acylhomoserine lactone profile.

  7. AmiE, a novel N-acylhomoserine lactone acylase belonging to the amidase family, from the activated-sludge isolate Acinetobacter sp. strain Ooi24.

    Science.gov (United States)

    Ochiai, Seiji; Yasumoto, Sera; Morohoshi, Tomohiro; Ikeda, Tsukasa

    2014-11-01

    Many Gram-negative bacteria use N-acyl-l-homoserine lactones (AHLs) as quorum-sensing signal molecules. We have reported that Acinetobacter strains isolated from activated sludge have AHL-degrading activity. In this study, we cloned the amiE gene as an AHL-degradative gene from the genomic library of Acinetobacter sp. strain Ooi24. High-performance liquid chromatography analysis revealed that AmiE functions as an AHL acylase, which hydrolyzes the amide bond of AHL. AmiE showed a high level of degrading activity against AHLs with long acyl chains but no activity against AHLs with acyl chains shorter than eight carbons. AmiE showed homology with a member of the amidases (EC 3.5.1.4) but not with any known AHL acylase enzymes. An amino acid sequence of AmiE from Ooi24 showed greater than 99% identities with uncharacterized proteins from Acinetobacter ursingii CIP 107286 and Acinetobacter sp. strain CIP 102129, but it was not found in the draft or complete genome sequences of other Acinetobacter strains. The presence of transposase-like genes around the amiE genes of these three Acinetobacter strains suggests that amiE is transferred by a putative transposon. Furthermore, the expression of AmiE in Pseudomonas aeruginosa PAO1 reduced AHL accumulation and elastase activity, which were regulated by AHL-mediated quorum sensing.

  8. hexA of Erwinia carotovora ssp. carotovora strain Ecc71 negatively regulates production of RpoS and rsmB RNA, a global regulator of extracellular proteins, plant virulence and the quorum-sensing signal, N-(3-oxohexanoyl)-L-homoserine lactone.

    Science.gov (United States)

    Mukherjee, A; Cui, Y; Ma, W; Liu, Y; Chatterjee, A K

    2000-04-01

    The soft-rotting bacterium, Erwinia carotovora ssp. carotovora (E. c. carotovora), produces an array of extracellular enzymes (= exoenzymes), including pectate lyase (Pel), polygalacturonase (Peh), cellulase (Cel) and protease (Prt), as well as HarpinEcc, the elicitor of hypersensitive reaction (HR). The production of these exoenzymes and HarpinEcc responds to plant products and the quorum-sensing signal [N-(3-oxohexanoyl)-L-homoserine lactone; OHL] and is subject to both transcriptional and post-transcriptional regulation. hexA of E. c. carotovora strain Ecc71 (hereafter hexA71), like that of another E. c. carotovora strain, negatively controls the production of exoenzymes, OHL and virulence in E. c. carotovora strain Ecc71. In addition to exoenzymes, HexA71 negatively regulates the expression of hrpNEcc, the structural gene for HarpinEcc. Exoenzyme overproduction is abolished by OHL deficiency in a HexA- and Ohll- double mutant, indicating that HexA and OHL are components of a common regulatory pathway controlling exoenzyme production. HexA71 negatively affects RpoS, as the levels of this alternative sigma factor are higher in the HexA- mutant than in the HexA+ strain. However, a HexA- and RpoS double mutant produces higher levels of exoenzymes and transcripts of pel-1, peh-1 and celVgenes than the HexA- and RpoS+ parent. Thus, the elevated levels of RpoS protein in the HexA- mutant do not account for exoenzyme overproduction. The following evidence associates for the first time the phenotypic changes in the HexA mutant to overproduction of rsmB RNA, a global regulator of exoenzymes, HarpinEcc, OHL and secondary metabolites. Analyses of rsmB transcripts and expression of an rsmB-lacZoperon fusion in E. c. carotovora strain Ecc71 revealed that HexA71 negatively regulates transcription of rsmB. Multiple copies of hexA71+ DNA suppress various phenotypes, including exoenzyme production in E. c. carotovora strain Ecc71, and concomitantly inhibit the production of rsm

  9. 拟南芥GCR2参与感应N-丁酰基高丝氨酸内酯过程的初步研究%Preliminarily Research on Involvement ofArabidopsisGCR2 Responsing to N-Butyryl-DL-homoserine Lactone

    Institute of Scientific and Technical Information of China (English)

    艾秋实; 张哲; 屈凌波; 刘方; 赵芊; 宋水山

    2015-01-01

    N-丁酰基高丝氨酸内酯(C4-HSL)是革兰氏阴性菌主要的群体感应信号,其能促进植物生长发育,激活细胞膜表面的Ca2+通道,从而参与调控植物的生理代谢。然而,植物感应C4-HSL的分子机制并不清楚。拟南芥GCR2作为ABA的受体,对植物的生理代谢十分重要。旨在探寻GCR2是否参与拟南芥感应C4-HSL的过程。qRT-PCR结果表明,C4-HSL处理后1 h, GCR2基因表达量出现明显上调并在6 h后达到最大值,说明C4-HSL可调节GCR2。ELISA结果显示,GCR2蛋白表达量也在6 h达到最大值。对体外表达的GCR2进行纯化和浓缩,使其达到0.6 mg/mL后进行微量热泳动(MST)检测。MST测得C4-HSL与GCR2的解离常数(Kd)为166 nmol/L,显示出较强的结合能力。用BSA作为阴性对照,表明C4-HSL与GCR2的结合具有一定的特异性。这些结果表明GCR2可能参与了拟南芥感应C4-HSL的过程。%N-Butyryl-DL-homoserine lactone(C4-HSL)is a main quorum sensing signal in gram-negative bacteria. It could significantly promote root elongation and activate Ca2+ channel at cytomembrane. C4-HSL can regulate metabolization of plant. However, little is known about the molecular mechanism of plants responding to C4-HSL.Arabidopsis thalianaGCR2 is receptor of abscisic acid(ABA). It is important for metabolization of plant. This research aimed to explore whether theGCR2 is involved in the process ofArabidopsis thaliana reacting to C4-HSL. qRT-PCR showed that C4-HSL could regulate expression of GCR2. Expression of GCR2 was significantly upregulated after 1 h treated by C4-HSL and maximaized at 6 h. ELISA also showed that expression of GCR2 maximaized at 6 h. GCR2 was purified and condensed to 0.6 mg/mL for Microscale Thermophoresis(MST)measurement. MST indicated that dissociation constant(Kd)of GCR2 and C4-HSL was 166 nmol/L, which meant that they had strong binding affinity. Taking BSA as negative control, this certified that

  10. Characterization of N-Acylhomoserine Lactones Produced by Bacteria Isolated from Industrial Cooling Water Systems

    Directory of Open Access Journals (Sweden)

    Noriya Okutsu

    2015-12-01

    Full Text Available The cooling water systems are used to remove heat generated in the various industries. Biofouling of the cooling water systems causes blocking of condenser pipes and the heat exchanger tubes. In many Gram-negative bacteria, N-acylhomoserine lactone (AHL are used as quorum-sensing signal molecule and associated with biofilm formation. To investigate the relationship between quorum sensing and biofouling in the cooling water system, we isolated a total of 192 bacterial strains from the five cooling water systems, and screened for AHL production. Seven isolates stimulated AHL-mediated purple pigment production in AHL reporter strain Chromobacterium violaceum CV026 or VIR07. Based on their 16S rRNA gene sequences, AHL-producing isolates were assigned to Aeromonas hydrophila, Lysobacter sp., Methylobacterium oryzae, and Bosea massiliensis. To the best of our knowledge, B. massiliensis and Lysobacter sp. have not been reported as AHL-producing species in the previous researches. AHLs extracted from the culture supernatants of B. massiliensis and Lysobacter sp. were identified by liquid chromatography-mass spectrometry. AHLs produced by B. massiliensis were assigned as N-hexanoyl-l-homoserine lactone (C6-HSL, N-(3-oxohexanoyl-l-homoserine lactone (3-oxo-C6-HSL, and N-(3-oxooctanoyl-l-homoserine lactone (3-oxo-C8-HSL. AHLs produced by Lysobacter sp. were assigned as N-decanoyl-l-homoserine lactone (C10-HSL and N-(3-oxodecanoyl-l-homoserine lactone (3-oxo-C10-HSL. This is the first report of identification of AHLs produced by B. massiliensis and Lysobacter sp. isolated from the cooling water system.

  11. Combined Effects of Curcumin and (-)-Epigallocatechin Gallate on Inhibition of N-Acylhomoserine Lactone-Mediated Biofilm Formation in Wastewater Bacteria from Membrane Bioreactor.

    Science.gov (United States)

    Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

    2015-11-01

    This work investigated the potential of curcumin (CCM) and (-)-epigallocatechin gallate (EGCG) to inhibit N-acyl homoserine lactone (AHL)-mediated biofilm formation in gramnegative bacteria from membrane bioreactor (MBR) activated sludge. The minimum inhibitory concentrations (MICs) of CCM alone against all the tested bacteria were 200-350 μg/ml, whereas those for EGCG were 300-600 μg/ml. Biofilm formation at one-half MICs indicated that CCM and EGCG alone respectively inhibited 52-68% and 59-78% of biofilm formation among all the tested bacteria. However, their combination resulted in 95-99% of biofilm reduction. Quorum sensing inhibition (QSI) assay with known biosensor strains demonstrated that CCM inhibited the expression of C4 and C6 homoserine lactones (HSLs)-mediated phenotypes, whereas EGCG inhibited C4, C6, and C10 HSLs-based phenotypes. The Center for Disease Control biofilm reactor containing a multispecies culture of nine bacteria with onehalf MIC of CCM (150 μg/ml) and EGCG (275 μg/ml) showed 17 and 14 μg/cm(2) of extracellular polymeric substances (EPS) on polyvinylidene fluoride membrane surface, whereas their combination (100 μg/ml of each) exhibited much lower EPS content (3 μg/cm(2)). Confocal laser scanning microscopy observations also illustrated that the combination of compounds tremendously reduced the biofilm thickness. The combined effect of CCM with EGCG clearly reveals for the first time the enhanced inhibition of AHL-mediated biofilm formation in bacteria from activated sludge. Thus, such combined natural QSI approach could be used for the inhibition of membrane biofouling in MBRs treating wastewaters.

  12. Functional characterization of a soybean growth stimulator Bradyrhizobium sp. strain SR-6 showing acylhomoserine lactone production.

    Science.gov (United States)

    Ali, Amanat; Ayesha; Hameed, Sohail; Imran, Asma; Iqbal, Mazhar; Iqbal, Javed; Oresnik, Ivan J

    2016-09-01

    A soybean nodule endophytic bacterium Bradyrhizobium sp. strain SR-6 was characterized for production of acyl homoserine lactones (AHLs) as quorum sensing molecules. Mass spectrometry analysis of AHLs revealed the presence of C6-HSL, 3OH-C6-HSL, C8-HSL, C10-HSL, 3oxoC10-HSL, 3oxo-C12-HSL and 3OH-C12-HSL which are significantly different from those reported earlier in soybean symbionts. Purified AHL extracts significantly improved wheat and soybean seedling growth and root hair development along with increased soybean nodulation under axenic conditions. A positive correlation was observed among in vivo nitrogenase and catalase enzyme activities of the strain SR-6. Transmission electron microscopic analysis showed the cytochemical localization of catalase activity within the bacteroids, specifically attached to the peribacteroidal membrane. Root and nodule colonization proved rhizosphere competence of SR-6. The inoculation of SR-6 resulted in increased shoot length (13%), plant dry matter (50%), grain weight (16%), seed yield (20%) and N-uptake (14%) as compared to non-inoculated soybean plants. The symbiotic bacterium SR-6 has potential to improve soybean growth and yield in sub-humid climate of Azad Jammu and Kashmir region of Pakistan. The production and mass spectrometric profiling of AHLs as well as in vivo cytochemical localization of catalase enzyme activity in soybean Bradyrhizobium sp. have never been reported earlier elsewhere before our these investigations.

  13. Influence of bacterial N-acyl-homoserinelactones on growth parameters, pigments, antioxidative capacities and the xenobiotic phase II detoxification enzymes in barley and yam bean

    Directory of Open Access Journals (Sweden)

    Christine eGoetz-Roesch

    2015-04-01

    Full Text Available Bacteria are able to communicate with each other and sense their environment in a population density dependent mechanism known as quorum sensing (QS. N-acyl-homoserine lactones (AHLs are the QS signalling compounds of Gram-negative bacteria which are frequent colonizers of rhizospheres. While cross-kingdom signalling and AHL-dependent gene expression in plants has been confirmed, the responses of enzyme activities in the eukaryotic host upon AHLs are unknown. Since AHL are thought to be used as so-called plant boosters or strengthening agents, which might change their resistance towards radiation and/or xenobiotic stress, we have examined the plants’ pigment status and their antioxidative and detoxifying capacities upon AHL treatment. Because the yield of a crop plant should not be negatively influenced, we have also checked for growth and root parameters.We investigated the influence of three different AHLs, namely N-hexanoyl- (C6-HSL, N-octanoyl- (C8-HSL and N-decanoyl- homoserine lactone (C10-HSL on two agricultural crop plants. The AHL-effects on Hordeum vulgare (L. as an example of a monocotyledonous crop and on the tropical leguminous crop plant Pachyrhizus erosus (L were compared. While plant growth and pigment contents in both plants showed only small responses to the applied AHLs, AHL treatment triggered tissue- and compound-specific changes in the activity of important detoxification enzymes. The activity of dehydroascorbate reductase (DHAR in barley shoots after C10-HSL treatment for instance increased up to 384% of control plant levels, whereas superoxide dismutase (SOD activity in barley roots was decreased down to 23% of control levels upon C6-HSL treatment. Other detoxification enzymes reacted similarly within this range, with interesting clusters of positive or negative answers towards AHL treatment. In general the changes on the enzyme level were more severe in barley than in yam bean which might be due to the different

  14. Functional Characterization of Triclosan-Resistant Enoyl-acyl-carrier Protein Reductase (FabV) in Pseudomonas aeruginosa

    Science.gov (United States)

    Huang, Yong-Heng; Lin, Jin-Shui; Ma, Jin-Cheng; Wang, Hai-Hong

    2016-01-01

    Pseudomonas aeruginosa is extremely resistant to triclosan. Previous studies have shown that P. aeruginosa encodes a triclosan-resistant enoyl-acyl-carrier protein reductase (ENR), FabV, and that deletion of fabV causes P. aeruginosa to be extremely sensitive to triclosan. In this report, we complemented a P. aeruginosa fabV deletion strain with several triclosan-resistant ENR encoding genes, including Vibrio cholerae fabV, Bacillus subtilis fabL and Enterococcus faecalis fabK. All complemented strains restored triclosan resistance to the level of the wild-type strain, which confirmed that triclosan-resistant ENR allows P. aeruginosa to be extremely resistant to triclosan. Moreover, fabV exhibits pleiotropic effects. Deletion of fabV led P. aeruginosa to show attenuated swarming motility, decreased rhamnolipid, pyoverdine and acyl-homoserine lactones (AHLs) production. Complementation of the fabV mutant with any one ENR encoding gene could restore these features to some extent, in comparison with the wild-type strain. Furthermore, we found that addition of exogenous AHLs could restore the fabV mutant strain to swarm on semisolid plates and to produce more virulence factors than the fabV mutant strain. These findings indicate that deletion of fabV reduced the activity of ENR in P. aeruginosa, decreased fatty acid synthesis, and subsequently depressed the production of AHLs and other virulence factors, which finally may led to a reduction in the pathogenicity of P. aeruginosa. Therefore, fabV should be an ideal target for the control of P. aeruginosa infectivity. PMID:27965638

  15. Comprehensive profiling of N-acylhomoserine lactones produced by Yersinia pseudotuberculosis using liquid chromatography coupled to hybrid quadrupole-linear ion trap mass spectrometry.

    Science.gov (United States)

    Ortori, Catharine A; Atkinson, Steve; Chhabra, Siri Ram; Cámara, Miguel; Williams, Paul; Barrett, David A

    2007-01-01

    A method for the comprehensive profiling of the N-acylhomoserine lactone (AHL) family of bacterial quorum-sensing molecules is presented using liquid chromatography (LC) coupled to hybrid quadrupole-linear ion trap (QqQLIT) mass spectrometry. Information-dependent acquisition (IDA), using triggered combinations of triple-quadrupole and linear ion trap modes in the same LC-MS/MS run, was used to simultaneously screen, quantify and identify multiple AHLs in a single sample. This MS method uses common AHL fragment ions attributed to the homoserine moiety and the 3-oxo-, 3-hydroxy- or unsubstituted acyl side chains, to identify unknown AHLs in cell-free culture supernatants in an unbiased manner. This LC-MS technique was applied to determine the relative molar ratios of AHLs produced by Yersinia pseudotuberculosis and the consequences of inactivating by mutation either or both of the AHL synthase genes (ypsI and ytbI) on AHL profile and concentration. The Y. pseudotuberculosis wild type but not the ypsI ytbI double mutant produced at least 24 different AHLs with acyl chains ranging from C4 to C15 with or without 3-oxo or 3-hydroxy substituents. YtbI, in contrast to YpsI, could direct the synthesis of all of the AHLs identified. The most abundant and hence most biologically relevant Y. pseudotuberculosis AHLs were found to be the 3-oxo-substituted C6, C7 and C8 AHLs and the unsubstituted C6 and C8 compounds. The LC-QqQLIT methodology is broadly applicable to quorum-sensing signal molecule analysis and can provide comprehensive AHL profiles and concentrations from a single sample and simultaneously collect confirmatory spectra for each AHL identified.

  16. Improvement of bioelectrochemical property and energy recovery by acylhomoserine lactones (AHLs) in microbial electrolysis cells (MECs)

    Science.gov (United States)

    Liu, Wenzong; Cai, Weiwei; Ma, Anzhou; Ren, Ge; Li, Zhiling; Zhuang, Guoqiang; Wang, Aijie

    2015-06-01

    Quorum sensing (QS) has been extensively studied as a cell-cell communication system, where small chemical signal molecules (acylhomoserine lactones, AHLs) can regulate the bacterial communications in bioelectrochemical systems via chemical signaling and electric signaling. In this study, electrochemical activity of bio-anode is substantially promoted by adding two kinds of AHLs with different chain length at the stage of community formation in microbial electrolysis cells (MECs). Hydrogen yield increase is observed by adding of two chain length AHLs, 3-oxo-hexanoyl-homoserine lactone (3OC6-HSL) and 3-oxo-dodecanoyl homoserine lactone (3OC12-HSL). A higher MEC current is acquired with addition of 3OC6-HSL than 3OC12-HSL at a fixed voltage of 0.8 V (vs. SHE). The highest yield is up to 3.8 ± 0.2 mol H2 mol-1 acetate at 10 μM 3OC6-HSL, which is increased 29% over control MECs. Evaluated on applied voltage, energy efficiency is increased to 171.6 ± 21.3% with short chain AHL, however, no significant improvement is performed on energy efficiency and coulombic efficiency with long-chain AHL. The study shows that bioelectrochemical characteristics of MECs varied on the chain length of AHL signal molecules and short-chain AHLs have a more positive effect on electron transfer and energy recovery in MECs.

  17. Studies on the mechanism, selectivity, and synthetic utility of lactone reduction using SmI(2) and H(2)O.

    Science.gov (United States)

    Parmar, Dixit; Duffy, Lorna A; Sadasivam, Dhandapani V; Matsubara, Hiroshi; Bradley, Paul A; Flowers, Robert A; Procter, David J

    2009-10-28

    Although simple aliphatic esters and lactones have long been thought to lie outside the reducing range of SmI(2), activation of the lanthanide reagent by H(2)O allows some of these substrates to be manipulated in an unprecedented fashion. For example, the SmI(2)-H(2)O reducing system shows complete selectivity for the reduction of 6-membered lactones over other classes of lactones and esters. The kinetics of reduction has been studied using stopped-flow spectrophotometry. Experimental and computational studies suggest that the origin of the selectivity lies in the initial electron-transfer to the lactone carbonyl. The radical intermediates formed during lactone reduction with SmI(2)-H(2)O can be exploited in cyclizations to give cyclic ketone (or ketal) products with high diastereoselectivity. The cyclizations constitute the first examples of ester-alkene radical cyclizations in which the ester carbonyl acts as an acyl radical equivalent.

  18. 4-Hydroxy-7-oxo-5-heptenoic Acid Lactone Induces Angiogenesis through Several Different Molecular Pathways.

    Science.gov (United States)

    Guo, Junhong; Linetsky, Mikhail; Yu, Annabelle O; Zhang, Liang; Howell, Scott J; Folkwein, Heather J; Wang, Hua; Salomon, Robert G

    2016-12-19

    Oxidative stress and angiogenesis have been implicated not only in normal phenomena such as tissue healing and remodeling but also in many pathological processes. However, the relationships between oxidative stress and angiogenesis still remain unclear, although oxidative stress has been convincingly demonstrated to influence the progression of angiogenesis under physiological and pathological conditions. The retina is particularly susceptible to oxidative stress because of its intensive oxygenation and high abundance of polyunsaturated fatty acyls. In particular, it has high levels of docosahexanoates, whose oxidative fragmentation produces 4-hydroxy-7-oxo-5-heptenoic acid lactone (HOHA-lactone). Previously, we found that HOHA-lactone is a major precursor of 2-(ω-carboxyethyl)pyrrole (CEP) derivatives, which are tightly linked to age-related macular degeneration (AMD). CEPs promote the pathological angiogenesis of late-stage AMD. We now report additional mechanisms by which HOHA-lactone promotes angiogenesis. Using cultured ARPE-19 cells, we observed that HOHA-lactone induces secretion of vascular endothelial growth factor (VEGF), which is correlated to increases in reactive oxygen species and decreases in intracellular glutathione (GSH). Wound healing and tube formation assays provided, for the first time, in vitro evidence that HOHA-lactone induces the release of VEGF from ARPE-19 cells, which promotes angiogenesis by human umbilical vein endothelial cells (HUVEC) in culture. Thus, HOHA-lactone can stimulate vascular growth through a VEGF-dependent pathway. In addition, results from MTT and wound healing assays as well as tube formation experiments showed that GSH-conjugated metabolites of HOHA-lactone stimulate HUVEC proliferation and promote angiogenesis in vitro. Previous studies demonstrated that HOHA-lactone, through its CEP derivatives, promotes angiogenesis in a novel Toll-like receptor 2-dependent manner that is independent of the VEGF receptor or VEGF

  19. Acylation of Therapeutic Peptides

    DEFF Research Database (Denmark)

    Trier, Sofie; Henriksen, Jonas Rosager; Jensen, Simon Bjerregaard

    peptides are similar in size and structure, but oppositely charged at physiological pH. Both peptides were acylated with linear acyl chains of systematically increasing length, where sCT was furthermore acylated at two different positions on the peptide backbone. For GLP-2, we found that increasing acyl...... stems from a synergy between the positive peptide charge and membrane-active acyl moiety, supported by its pH-dependency, whereby the effect increased with decreasing pH and concomitant charge increase. The extent of permeation enhancing effect was highly dependent on acylation chain length and position...

  20. Published the papers of HPLC-MS analysis—Traditional Chinese medicine

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Medicinal materials Ma Chenchen, Li Bailin, Ou Jie, Wang Jing, Zhao Junhong. Detection of N-acyl-homoserine lactones class signal molecules of quorum sensing secreted by bacteria using high performance liquid chromatography-mass spectrometry/ mass spect

  1. Catabolism of hydroxyacids and biotechnological production of lactones by Yarrowia lipolytica.

    Science.gov (United States)

    Waché, Y; Aguedo, M; Nicaud, J-M; Belin, J-M

    2003-06-01

    The gamma- and delta-lactones of less than 12 carbons constitute a group of compounds of great interest to the flavour industry. It is possible to produce some of these lactones through biotechnology. For instance, gamma-decalactone can be obtained by biotransformation of methyl ricinoleate. Among the organisms used for this bioproduction, Yarrowia lipolytica is a yeast of choice. It is well adapted to growth on hydrophobic substrates, thanks to its efficient and numerous lipases, cytochrome P450, acyl-CoA oxidases and its ability to produce biosurfactants. Furthermore, genetic tools have been developed for its study. This review deals with the production of lactones by Y. lipolytica with special emphasis on the biotransformation of methyl ricinoleate to gamma-decalactone. When appropriate, information from the lipid metabolism of other yeast species is presented.

  2. Corymbiferan lactones from Penicillium hordei

    DEFF Research Database (Denmark)

    Overy, David Patrick; Blunt, J.W.

    2004-01-01

    Cultivation of a strain of Penicillium hordei on macerated tulip tissue agar resulted in the stimulated production of a series of four novel hydroxymethyl naphthalene carboxylic acid lactones from the fungus. The naphthalene derivatives were isolated using a combination of vacuum liquid chromatog...... chromatography and preparative HPLC. Their structures were determined by 1D and 2D NMR techniques in conjunction with high-resolution electrospray mass spectrometry (HRESIMS). These metabolites were given the trivial names corymbiferan lactones A-D (1-4)....

  3. Effect of acyl-CoA oxidase activity on the accumulation of gamma-decalactone by the yeast Yarrowia lipolytica: a factorial approach.

    Science.gov (United States)

    García, Erandi Escamilla; Nicaud, Jean-Marc; Belin, Jean-Marc; Waché, Yves

    2007-10-01

    beta-Oxidation is a cyclic pathway involved in the degradation of lipids. In yeast, it occurs in peroxisomes and the first step is catalyzed by an acyl-CoA oxidase (Aoxp). The yeast Yarrowia lipolytica possesses several genes (POX) coding for Aoxps. This study is based on the factorial analysis of results obtained with the many POX derivative strains that have been constructed previously. The effect of interactions between Aoxps on the acyl-CoA oxidase (Aox) activity was important even at the second order. We then investigated the effect of Aox activity on growth and lactone production. Aox activity was correlated with acidification of the medium by cells and with cellular growth but not with lactone production, although Aox activity on short chains was inversely correlated with lactone accumulation. Due to the poor correlation between Aox activity and lactone production, the modeling of this parameter gave no satisfactory results but growth depending on Aox activity was modeled.

  4. Interference of Quorum Sensing by Delftia sp. VM4 Depends on the Activity of a Novel N-Acylhomoserine Lactone-Acylase.

    Directory of Open Access Journals (Sweden)

    Vimal B Maisuria

    Full Text Available Turf soil bacterial isolate Delftia sp. VM4 can degrade exogenous N-acyl homoserine lactone (AHL, hence it effectively attenuates the virulence of bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum strain BR1 (Pcc BR1 as a consequence of quorum sensing inhibition.Isolated Delftia sp. VM4 can grow in minimal medium supplemented with AHL as a sole source of carbon and energy. It also possesses the ability to degrade various AHL molecules in a short time interval. Delftia sp. VM4 suppresses AHL accumulation and the production of virulence determinant enzymes by Pcc BR1 without interference of the growth during co-culture cultivation. The quorum quenching activity was lost after the treatment with trypsin and proteinase K. The protein with quorum quenching activity was purified by three step process. Matrix assisted laser desorption/ionization-time of flight (MALDI-TOF and Mass spectrometry (MS/MS analysis revealed that the AHL degrading enzyme (82 kDa demonstrates homology with the NCBI database hypothetical protein (Daci_4366 of D. acidovorans SPH-1. The purified AHL acylase of Delftia sp. VM4 demonstrated optimum activity at 20-40°C and pH 6.2 as well as AHL acylase type mode of action. It possesses similarity with an α/β-hydrolase fold protein, which makes it unique among the known AHL acylases with domains of the N-terminal nucleophile (Ntn-hydrolase superfamily. In addition, the kinetic and thermodynamic parameters for hydrolysis of the different AHL substrates by purified AHL-acylase were estimated. Here we present the studies that investigate the mode of action and kinetics of AHL-degradation by purified AHL acylase from Delftia sp. VM4.We characterized an AHL-inactivating enzyme from Delftia sp. VM4, identified as AHL acylase showing distinctive similarity with α/β-hydrolase fold protein, described its biochemical and thermodynamic properties for the first time and revealed its potential application as an anti

  5. Sesquiterpene Lactones from Notoseris Porphyrolepis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Two new sesquiterpene lactones, notoserolides A and B, along with 12 known compounds were isolated from the aerial parts of Notoseris porphyrolepis.By means of spectral methods including MS, NMR (1H NMR, 13C NMR, DEPT, HMQC, HMBC) and X-ray diffraction, as well as chemical reactions, the structures of notoserolides A and B were established as austricin 8-O-β-D-glucopyranoside and 8-O-senecioylaustricin, respectively.

  6. Quorum Sensing Activity in Pandoraea pnomenusa RB38

    Directory of Open Access Journals (Sweden)

    Robson Ee

    2014-06-01

    Full Text Available Strain RB38 was recovered from a former dumping area in Malaysia. MALDI-TOF mass spectrometry and genomic analysis identified strain RB-38 as Pandoraea pnomenusa. Various biosensors confirmed its quorum sensing properties. High resolution triple quadrupole liquid chromatography–mass spectrometry analysis was subsequently used to characterize the N-acyl homoserine lactone production profile of P. pnomenusa strain RB38, which validated that this isolate produced N-octanoyl homoserine lactone as a quorum sensing molecule. This is the first report of the production of N-octanoyl homoserine lactone by P. pnomenusa strain RB38.

  7. Involvement of Acyl Coenzyme A Oxidase Isozymes in Biotransformation of Methyl Ricinoleate into γ-Decalactone by Yarrowia lipolytica

    Science.gov (United States)

    Waché, Yves; Laroche, Céline; Bergmark, Karin; Møller-Andersen, Charlotte; Aguedo, Mario; Le Dall, Marie-Thérèse; Wang, Huijie; Nicaud, Jean-Marc; Belin, Jean-Marc

    2000-01-01

    We reported previously on the function of acyl coenzyme A (acyl-CoA) oxidase isozymes in the yeast Yarrowia lipolytica by investigating strains disrupted in one or several acyl-CoA oxidase-encoding genes (POX1 through POX5) (H. Wang et al., J. Bacteriol. 181:5140–5148, 1999). Here, these mutants were studied for lactone production. Monodisrupted strains produced similar levels of lactone as the wild-type strain (50 mg/liter) except for Δpox3, which produced 220 mg of γ-decalactone per liter after 24 h. The Δpox2 Δpox3 double-disrupted strain, although slightly affected in growth, produced about 150 mg of lactone per liter, indicating that Aox2p was not essential for the biotransformation. The Δpox2 Δpox3 Δpox5 triple-disrupted strain produced and consumed lactone very slowly. On the contrary, the Δpox2 Δpox3 Δpox4 Δpox5 multidisrupted strain did not grow or biotransform methyl ricinoleate into γ-decalactone, demonstrating that Aox4p is essential for the biotransformation. PMID:10698800

  8. Involvement of acyl coenzyme A oxidase isozymes in biotransformation of methyl ricinoleate into gamma-decalactone by Yarrowia lipolytica.

    Science.gov (United States)

    Waché, Y; Laroche, C; Bergmark, K; Møller-Andersen, C; Aguedo, M; Le Dall, M T; Wang, H; Nicaud, J M; Belin, J M

    2000-03-01

    We reported previously on the function of acyl coenzyme A (acyl-CoA) oxidase isozymes in the yeast Yarrowia lipolytica by investigating strains disrupted in one or several acyl-CoA oxidase-encoding genes (POX1 through POX5) (H. Wang et al., J. Bacteriol. 181:5140-5148, 1999). Here, these mutants were studied for lactone production. Monodisrupted strains produced similar levels of lactone as the wild-type strain (50 mg/liter) except for Deltapox3, which produced 220 mg of gamma-decalactone per liter after 24 h. The Deltapox2 Deltapox3 double-disrupted strain, although slightly affected in growth, produced about 150 mg of lactone per liter, indicating that Aox2p was not essential for the biotransformation. The Deltapox2 Deltapox3 Deltapox5 triple-disrupted strain produced and consumed lactone very slowly. On the contrary, the Deltapox2 Deltapox3 Deltapox4 Deltapox5 multidisrupted strain did not grow or biotransform methyl ricinoleate into gamma-decalactone, demonstrating that Aox4p is essential for the biotransformation.

  9. Molecular and vibrational structure of the extracellular bacterial signal compound N-butyryl-homoserine lactone (C4-HSL)

    DEFF Research Database (Denmark)

    Bak, Jimmy; Spanget-Larsen, Jens

    2009-01-01

    The molecular and vibrational structure of the title compound (C4-HSL) was studied by experimental and theoretical methods. The infrared (IR) absorption spectrum was measured in the solid state and in CCl4 suspension. The observed absorption bands were compared with transitions obtained with B3LYP....../cc-pVTZ density functional theory (DFT) calculations. Two stable molecular conformations were predicted, corresponding to an endo- and an exo-conformer with similar energies. Intermolecular amide-amide hydrogen bonding in the crystal state was approximated by a simple cluster model, leading to excellent agreement...

  10. Sesquiterpenoids Lactones: Benefits to Plants and People

    Directory of Open Access Journals (Sweden)

    Carol Wagstaff

    2013-06-01

    Full Text Available Sesquiterpenoids, and specifically sesquiterpene lactones from Asteraceae, may play a highly significant role in human health, both as part of a balanced diet and as pharmaceutical agents, due to their potential for the treatment of cardiovascular disease and cancer. This review highlights the role of sesquiterpene lactones endogenously in the plants that produce them, and explores mechanisms by which they interact in animal and human consumers of these plants. Several mechanisms are proposed for the reduction of inflammation and tumorigenesis at potentially achievable levels in humans. Plants can be classified by their specific array of produced sesquiterpene lactones, showing high levels of translational control. Studies of folk medicines implicate sesquiterpene lactones as the active ingredient in many treatments for other ailments such as diarrhea, burns, influenza, and neurodegradation. In addition to the anti-inflammatory response, sesquiterpene lactones have been found to sensitize tumor cells to conventional drug treatments. This review explores the varied ecological roles of sesquiterpenes in the plant producer, depending upon the plant and the compound. These include allelopathy with other plants, insects, and microbes, thereby causing behavioural or developmental modification to these secondary organisms to the benefit of the sesquiterpenoid producer. Some sesquiterpenoid lactones are antimicrobial, disrupting the cell wall of fungi and invasive bacteria, whereas others protect the plant from environmental stresses that would otherwise cause oxidative damage. Many of the compounds are effective due to their bitter flavor, which has obvious implications for human consumers. The implications of sesquiterpenoid lactone qualities for future crop production are discussed.

  11. Tandem Mass Spectrometry Detection of Quorum Sensing Activity in Multidrug Resistant Clinical Isolate Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2014-01-01

    Full Text Available Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs. These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL and N-octanoyl-homoserine lactone (C8-HSL, was detected.

  12. Allergenic sesquiterpene lactones from cushion bush (Leucophyta brownii Cass.)

    DEFF Research Database (Denmark)

    Paulsen, Evy; Gade Hyldgaard, Mette; Andersen, Klaus E.

    2017-01-01

    BACKGROUND: The Australian cushion bush (Leucophyta brownii) of the Compositae family of plants has become a popular pot and container plant. The plant produces the sesquiterpene lactone allergen calocephalin. OBJECTIVES: To assess the sensitizing potential of sesquiterpene lactones from cushion ...

  13. Abietane lactones and iridoids from Goldfussia yunnanensis.

    Science.gov (United States)

    Yu, Hong-Wei; Li, Bo-Gang; Li, Guo-You; Li, Chang-Song; Fang, Dong-Mei; Zhang, Guo-Lin

    2007-12-01

    Two new abietane diterpene lactones (1--2), three new abietane diterpene lactone glycosides (3--5) and a new iridoid glycoside (6), together with five known compounds, were isolated from the aerial parts of Goldfussia yunnanensis. The new compounds were determined to be 18-hydroxyhelioscopinolide A (1), 18-oxohelioscopinolide A (2), 18-hydroxy-3-O-beta-D-glucopyranosylhelioscopinolide A (3), 3-O-beta-D-glucopyranosylhelioscopinolide A (4), 3-O-beta-D-galactopyranosylhelioscopinolide A (5), and 6-O-trans-cinnamoyl E-harpagoside (6) on the basis of spectral data and chemical evidence.

  14. Isolation and characterization of 9-lipoxygenase and epoxide hydrolase 2 genes: Insight into lactone biosynthesis in mango fruit (Mangifera indica L.).

    Science.gov (United States)

    Deshpande, Ashish B; Chidley, Hemangi G; Oak, Pranjali S; Pujari, Keshav H; Giri, Ashok P; Gupta, Vidya S

    2017-06-01

    Uniqueness and diversity of mango flavour across various cultivars are well known. Among various flavour metabolites lactones form an important class of aroma volatiles in certain mango varieties due to their ripening specific appearance and lower odour detection threshold. In spite of their biological and biochemical importance, lactone biosynthetic pathway in plants remains elusive. Present study encompasses quantitative real-time analysis of 9-lipoxygenase (Mi9LOX), epoxide hydrolase 2 (MiEH2), peroxygenase, hydroperoxide lyase and acyl-CoA-oxidase genes during various developmental and ripening stages in fruit of Alphonso, Pairi and Kent cultivars with high, low and no lactone content and explains their variable lactone content. Study also covers isolation, recombinant protein characterization and transient over-expression of Mi9LOX and MiEH2 genes in mango fruits. Recombinant Mi9LOX utilized linoleic and linolenic acids, while MiEH2 utilized aromatic and fatty acid epoxides as their respective substrates depicting their role in fatty acid metabolism. Significant increase in concentration of δ-valerolactone and δ-decalactone upon Mi9LOX over-expression and that of δ-valerolactone, γ-hexalactone and δ-hexalactone upon MiEH2 over-expression further suggested probable involvement of these genes in lactone biosynthesis in mango. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Enantioselective Syntheses of (-)- and (+)-Homocitric Acid Lactones.

    Science.gov (United States)

    Rodríguez R, Gastón H.; Biellmann, Jean-François

    1996-03-08

    Highly enantioselective syntheses of enantiomers of homocitric acid lactones (R)-5a and (S)-5b are described. Thermal Diels-Alder cycloadditions of 2a and 2b to 1,3-butadiene produced adducts 3a and 3b, respectively. Oxidative ozonolysis of latter adducts gave products 4a and 4b which after acid treatment afforded a mixture with 5a and 5b as major component. Acid lactones 5a and 5b were converted into their dimethyl esters 6a and 6b which were purified by chromatography. After saponification, the products obtained were crystallized to yield (-)- and (+)-homocitric acid lactones ((R)-5a and (S)-5b). Diastereomeric excess (de) of Diels-Alder adducts 3a and 3b was determined by means of Mosher esters of glycols 8a, 8b, and racemic 8. Diels-Alder cycloaddition products of lactones 2a and 2b to 1,3-butadiene showed a diastereoselectivity of 96%.

  16. Triacetic acid lactone production from Saccharomyces cerevisiae

    Science.gov (United States)

    Triacetic acid lactone (TAL) is a potential platform chemical produced from acetyl-CoA and malonyl-CoA by the Gerbera hybrida 2-pyrone synthase (2PS) gene. Studies are ongoing to optimize production, purification, and chemical modification of TAL, which can be used to create the commercial chemicals...

  17. The endocrine effects of acylated and des-acylated ghrelin

    Directory of Open Access Journals (Sweden)

    St-Pierre DH

    2012-08-01

    Full Text Available David E Andrich,1 Katherine Cianflone,2 Alain-Steve Comtois,1 Simon Lalonde,1 David H St-Pierre11Department of Kinesiology, Université du Québec à Montréal (UQAM, Montreal, Canada; 2Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec, CanadaAbstract: Acylated ghrelin is one of the few peptides known whose isolation and characterization follow the description of its receptor and its basic biological functions. Characterized initially for its somatotrophic properties, ghrelin was shown later to exert various effects on other important physiological functions in mammals, such as appetite, gastric acid secretion, gut motility, insulin sensitivity, adiposity, and energy expenditure. Further, ghrelin influences cardiac function, reproduction, and the immune system as well. Here we present an overview of the discovery and subsequent development of ghrelin as an important peptide hormone involved in the control of energy metabolism in humans and other mammals. Recently reported effects of acylated ghrelin on glucose/lipid uptake, de novo lipogenesis, gluconeogenesis, lipid-droplet formation, fatty acid transport into mitochondria, and mitochondrial activity are particularly emphasized and discussed.Keywords: Acylated ghrelin, des-acylated ghrelin, physiological functions, adipogenesis

  18. Thermodynamic properties of sesquiterpene lactone grossheimin

    Science.gov (United States)

    Kasenova, Sh. B.; Atazhanova, G. A.; Sagintaeva, Zh. I.; Kasenov, B. K.; Kishkentaeva, A. S.; Adekenov, S. M.

    2016-08-01

    The enthalpy of dissolution of sesquiterpene lactone grossheimin C15H18O4 is measured using a DAK-I-IA calorimeter at a lactone/ethanol (96%) molar ratios equal to 1 : 18000, 1 : 36000, and 1 : 72000. The standard enthalpy of dissolution of grossheimin in a 96% ethanol solution is calculated based on the resulting data. The temperature dependence of the heat capacity of grossheimin C p ° ˜ f ( T) is studied by means of dynamic calorimetry using a IT-C-400 device in the temperature range of 298.15-423 K. An equation describing this dependence is derived. The standard enthalpies of combustion, melting, and formation of grossheimin are calculated using approximate methods.

  19. Four new lactones from Botrytis cinerea.

    Science.gov (United States)

    Colmenares, Ana J; Durán-Patrón, Rosa M; Hernández-Galán, Rosario; Collado, Isidro G

    2002-11-01

    Four new lactones (1-4) have been isolated from Botrytis cinerea. Their structures were elucidated by interpretation of spectral data, mainly (1)H and (13)C NMR, including two-dimensional analysis (HOMOCOSY, HMQC, and HMBC). The phytotoxic activities of these new natural products have been evaluated. Compounds 1-3 were inactive, while 4 showed a phytotoxic effect when tested up to 250 ppm.

  20. Novel secoiridoid lactones from Jasminum multiflorum.

    Science.gov (United States)

    Shen, Y C; Chen, C H

    1989-01-01

    Four new secoiridoid lactones, jasmolactones A [1], B [2], C [3], and D [4], were isolated from the aerial part of Jasminum multiflorum. The structures of these compounds, which contain a novel bicyclic 2-oxo-oxepano[4,5-c]pyran ring system, were established by spectral analyses and chemical correlations. Pharmacological testing revealed that jasmolactones B and D possess coronary vasodilating and cardiotropic activities.

  1. Guaiane sesquiterpene lactones from Salvia nubicola (Lamiaceae).

    Science.gov (United States)

    Ali, Muhammad S; Ibrahim, Syed A; Ahmed, Shakeel; Lobkovsky, Emil

    2007-01-01

    A new sesquiterpene lactone, nubiol (1), belonging to the guaiane class, along with a dimer, bisnubidiol (2), has been isolated from Salvia nubicola collected from Quetta, Pakistan. The structures of both metabolites were elucidated with the aid of spectroscopic techniques including 2D-NMR. Additionally, the structure of nubiol (1) was finally confirmed via the single crystal X-ray diffraction. Nubiol (1) was found moderately active against Pseudomonas aeruginosa.

  2. Preparation and Characterization of Acylated Chitosan

    Institute of Scientific and Technical Information of China (English)

    LI Ming-chun; LIU Chao; XIN Mei-hua; ZHAO Huang; WANG Min; FENG Zhen; SUN Xiao-li

    2005-01-01

    Fully acylated chitosan and N, N-diacyl chitosan were prepared. The products were characterized by elemental analysis, FTIR and 1H NMR. The experimental results indicate that the average degree of acylation depends on the volume ratio of pyridine to chloroform in the reaction medium, the chain length of the acylation agent used, and the molecular weight of chitosan raw materials. The XRD measurements were carried out for pure chitosan, fully acylated chitosan and N, N-diacyl chitosan to verify the crystallinity change caused by the acylation.

  3. Thermodynamic characteristics of the formation of complexes of nickel(II) with L-homoserine

    Science.gov (United States)

    Gridchin, S. N.

    2016-12-01

    The formation of complexes of nickel(II) with L-homoserine at 298.15 K and ionic strengths I = 0.5, 1.0, and 1.5 (KNO3) are investigated by potentiometry and calorimetry. Standard characteristics of studied equilibria (log K°, Δr G°, Δr H°, and Δr S°) are determined.

  4. Chemical reporters for exploring protein acylation.

    Science.gov (United States)

    Thinon, Emmanuelle; Hang, Howard C

    2015-04-01

    Proteins are acylated by a variety of metabolites that regulates many important cellular pathways in all kingdoms of life. Acyl groups in cells can vary in structure from the smallest unit, acetate, to modified long-chain fatty acids, all of which can be activated and covalently attached to diverse amino acid side chains and consequently modulate protein function. For example, acetylation of Lys residues can alter the charge state of proteins and generate new recognition elements for protein-protein interactions. Alternatively, long-chain fatty-acylation targets proteins to membranes and enables spatial control of cell signalling. To facilitate the analysis of protein acylation in biology, acyl analogues bearing alkyne or azide tags have been developed that enable fluorescent imaging and proteomic profiling of modified proteins using bioorthogonal ligation methods. Herein, we summarize the currently available acylation chemical reporters and highlight their utility to discover and quantify the roles of protein acylation in biology.

  5. Lactones 42. Stereoselective enzymatic/microbial synthesis of optically active isomers of whisky lactone.

    Science.gov (United States)

    Boratyński, Filip; Smuga, Małgorzata; Wawrzeńczyk, Czesław

    2013-11-01

    Two different methods, enzyme-mediated reactions and biotrasformations with microorganisms, were applied to obtain optically pure cis- and trans-isomers of whisky lactone 4a and 4b. In the first method, eight alcohol dehydrogenases were investigated as biocatalysts to enantioselective oxidation of racemic erythro- and threo-3-methyloctane-1,4-diols (1a and 1b). Oxidation processes with three of them, alcohol dehydrogenases isolated from horse liver (HLADH) as well as recombinant from Escherichia coli and primary alcohol dehydrogenase (PADH I), were characterized by the highest degree of conversion with moderate enantioselectivity (ee=27-82%) of the reaction. In all enzymatic reactions enantiomerically enriched not naturally occurring isomers of trans-(-)-(4R,5S)-4b or cis-(+)-(4R,5R)-4a were formed preferentially. In the second strategy, based on microbial lactonization of γ-oxoacids, naturally occurring opposite isomers of whisky lactones were obtained. Trans-(+)-(4S,5R)-isomer (ee=99%) of whisky lactone 4b was stereoselectively formed as the only product of biotransformations of 3-methyl-4-oxooctanoic acid (5) catalyzed by Didimospheria igniaria KCH6651, Laetiporus sulphurens AM525, Chaetomium sp.1 KCH6670 and Saccharomyces cerevisiae AM464. Biotransformation of γ-oxoacid 5, in the culture of Beauveria bassiana AM278 and Pycnidiella resinae KCH50 afforded a mixtures of trans-(+)-(4S,5R)-4b with enantiomeric excess ee=99% and cis-(-)-(4S,5S)-4a with enantiomeric excesses ee=77% and ee=45% respectively.

  6. Quorum Sensing Regulation of Adhesion in Serratia Marcescens MG1 is surface dependent

    DEFF Research Database (Denmark)

    Labbate, M.; Zhu, H.; Thung, L.;

    2007-01-01

    Serratia marcescens is an opportunistic pathogen and a major cause of ocular infections. In previous studies of S. marcescens MG1, we showed that biofilm maturation and sloughing were regulated by N-acyl homoserine lactone (AHL)-based quorum sensing (QS). Because of the importance of adhesion...

  7. Evaluation of the impact of quorum sensing transcriptional regulator SdiA on long-term persistence and fecal shedding of Escherichia coli O157:H7 in weaned calves

    Science.gov (United States)

    Quorum sensing transcriptional regulator SdiA has been shown to enhance the survival of Escherichia coli O157:H7 (O157) in the acidic compartment of bovine rumen in response to N-acyl-L-homoserine lactones (AHLs) produced by the rumen bacteria. Bacteria that survive the rumen environment subsequentl...

  8. Protoanemonin: a natural quorum sensing inhibitor that selectively activates iron starvation response

    NARCIS (Netherlands)

    Fazzini, R.A.; Skindersoe, M.; Bielecki, M.; Puchalka, J.; Givskov, M.; Martins Dos Santos, V.A.P.

    2013-01-01

    Many Gram-negative bacteria employ cell-to-cell communication mediated by N-acyl homoserine lactones (quorum sensing) to control expression of a wide range of genes including, but not limited to, genes encoding virulence factors. Outside the laboratory, the bacteria live in complex communities where

  9. Eavesdropping by bacteria: the role of SdiA in Escherichia coli and Salmonella enterica serovar Typhimurium quorum sensing

    Science.gov (United States)

    Many gram-negative bacteria utilize N-acyl-L-homoserine lactones (AHLs) to sense and respond to their own population densities and to regulate gene transcription. The AHLs, produced by AHL synthases, bind to receptors belonging to the LuxR family of transcriptional regulators leading to activation...

  10. Quorum-sensing-directed protein expression in Serratia proteamaculans B5a

    DEFF Research Database (Denmark)

    Christensen, Allan Beck; Riedel, Kathrin; Eberl, Leo

    2003-01-01

    N-Acyl-L-homoserine-lactone-producing Serratia species are frequently encountered in spoiling foods of vegetable and protein origin. The role of quorum sensing in the food spoiling properties of these bacteria is currently being investigated. A set of luxR luxI homologous genes encoding a putative...

  11. Vibrio vulnificus produces quorum sensing signals of the AHL-class

    DEFF Research Database (Denmark)

    Valiente, E.; Bruhn, Jesper Bartholin; Nielsen, Kristian Fog

    2009-01-01

    been described in human strains of biotype 1, and here we show that the luxS gene which encodes AI-2 is present in all strains of V. vulnificus regardless of origin, biotype or serovar. In this study, we also demonstrate that V. vulnificus produces QS signals of the acylated homoserine lactone (AHL...

  12. Quorum sensing by peptide pheromones and two-component signal-transduction systems in Gram-positive bacteria

    NARCIS (Netherlands)

    Kleerebezem, Michiel; Quadri, Luis E.N.; Kuipers, Oscar P.; Vos, Willem M. de

    1997-01-01

    Cell-density-dependent gene expression appears to be widely spread in bacteria. This quorum-sensing phenomenon has been well established in Gram-negative bacteria, where N-acyl homoserine lactones are the diffusible communication molecules that modulate cell-density-dependent phenotypes. Similarly,

  13. Do marine natural products interfere with prokaryotic AHL regulatory systems?

    DEFF Research Database (Denmark)

    Kjelleberg, S.; Steinberg, P.; Givskov, Michael Christian

    1997-01-01

    signalling system. We demonstrate that halogenated furanones, a class of secondary metabolites produced by the Australian subtidal red alga DeLisea pulchra, interfere with the acylated homoserine lactone (AHL) regulatory system in several Gram-negative bacteria. Furanones were found to interfere with the AHL...

  14. Quorum sensing by peptide pheromones and two-component signal-transduction systems in Gram-positive bacteria

    NARCIS (Netherlands)

    Kleerebezem, Michiel; Quadri, Luis E.N.; Kuipers, Oscar P.; Vos, Willem M. de

    1997-01-01

    Cell-density-dependent gene expression appears to be widely spread in bacteria. This quorum-sensing phenomenon has been well established in Gram-negative bacteria, where N-acyl homoserine lactones are the diffusible communication molecules that modulate cell-density-dependent phenotypes. Similarly,

  15. Use of a Whole-Cell Biosensor and Flow Cytometry to Detect AHL Production by an Indigenous Soil Community During Decomposition

    DEFF Research Database (Denmark)

    Burmølle, Mette; Hansen, Lars Hestbjerg; Sørensen, Søren Johannes

    2005-01-01

    Quorum sensing, mediated by acylated homoserine lactones (AHLs), is well described for pure culture bacteria, but few studies report detection of AHL compounds in natural bacterial habitats. In this study, we detect AHL production during a degradation process in soil by use of whole-cell biosensor...

  16. Acylated flavone glycosides from Veronica.

    Science.gov (United States)

    Albach, Dirk C; Grayer, Renée J; Jensen, Søren Rosendal; Ozgökce, Fevzi; Veitch, Nigel C

    2003-12-01

    A survey of the flavonoid glycosides of selected taxa in the genus Veronica yielded two new acylated 5,6,7,3',4'-pentahydroxyflavone (6-hydroxyluteolin) glycosides and two unusual allose-containing acylated 5,7,8,4'-tetrahydroxyflavone (isoscutellarein) glycosides. The new compounds were isolated from V. liwanensis and V. longifolia and identified using NMR spectroscopy as 6-hydroxyluteolin 4'-methyl ether 7-O-alpha-rhamnopyranosyl(1"'-->2")[6"-O-acetyl-beta-glucopyranoside] and 6-hydroxyluteolin 7-O-(6"-O-(E)-caffeoyl)-beta-glucopyranoside, respectively. Isoscutellarein 7-O-(6"'-O-acetyl)-beta-allopyranosyl(1"'-->2")-beta-glucopyranoside was obtained from both V. intercedens and V. orientalis and its 4'-methyl ether from V. orientalis only. Complete 1H and 13C NMR spectral assignments are presented for both isoscutellarein glycosides. Two iridoid glucosides new to the genus Veronica (melittoside and globularifolin) were also isolated from V. intercedens.

  17. The Pseudomonas aeruginosa N-acylhomoserine lactone quorum sensing molecules target IQGAP1 and modulate epithelial cell migration.

    Directory of Open Access Journals (Sweden)

    Thommie Karlsson

    Full Text Available Quorum sensing (QS signaling allows bacteria to control gene expression once a critical population density is achieved. The Gram-negative human pathogen Pseudomonas aeruginosa uses N-acylhomoserine lactones (AHL as QS signals, which coordinate the production of virulence factors and biofilms. These bacterial signals can also modulate human cell behavior. Little is known about the mechanisms of the action of AHL on their eukaryotic targets. Here, we found that N-3-oxo-dodecanoyl-L-homoserine lactone 3O-C(12-HSL modulates human intestinal epithelial Caco-2 cell migration in a dose- and time-dependent manner. Using new 3O-C(12-HSL biotin and fluorescently-tagged probes for LC-MS/MS and confocal imaging, respectively, we demonstrated for the first time that 3O-C(12-HSL interacts and co-localizes with the IQ-motif-containing GTPase-activating protein IQGAP1 in Caco-2 cells. The interaction between IQGAP1 and 3O-C(12-HSL was further confirmed by pull-down assay using a GST-tagged protein with subsequent Western blot of IQGAP1 and by identifying 3O-C(12-HSL with a sensor bioassay. Moreover, 3O-C(12-HSL induced changes in the phosphorylation status of Rac1 and Cdc42 and the localization of IQGAP1 as evidenced by confocal and STED microscopy and Western blots. Our findings suggest that the IQGAP1 is a novel partner for P. aeruginosa 3O-C(12-HSL and likely the integrator of Rac1 and Cdc42- dependent altered cell migration. We propose that the targeting of IQGAP1 by 3O-C(12-HSL can trigger essential changes in the cytoskeleton network and be an essential component in bacterial--human cell communication.

  18. Aromaticine, a sesquiterpene lactone from Amblyopappus pusillus

    Directory of Open Access Journals (Sweden)

    Matías López-Rodríguez

    2008-02-01

    Full Text Available Aromaticine (systematic name: 4a,8-dimethyl-3-methylene-3,3a,4,4a,7a,8,9,9a-octahydroazuleno[6,5-b]furan-2,5-dione, C15H18O3, is a natural lactone isolated from Amblyopappus pusillus. The molecular structure and conformation agree with the results of Romo, Joseph-Nathan & Díaz [(1964. Tetrahedron, 20, 79–85]. The fused-ring system contains a seven-membered ring in a twist-boat conformation and two five-membered rings trans fused in envelope conformations.

  19. Two New Lactones Metabolized from Isoline by Rat Liver Microsomes

    Institute of Scientific and Technical Information of China (English)

    Jun TANG; Zheng Tao WANG; Teruaki AKAO; Norio NAKAMURA; Masao HATTORI

    2003-01-01

    Two new metabolites, namely bisline lactone and isolinecic acid lactone, were isolated from the resultant incubates after a scale-up incubation of isoline with rat liver microsomes. Their structures were determined by spectroscopic data, especially those from 1D and 2D NMR experiments.

  20. A Novel Lanostanoid Lactone From the Alga Hypnea cerricornis

    Institute of Scientific and Technical Information of China (English)

    XU, Xiao-Hua; CHEN, Xiao; LU, Jian-Hua; YAO, Guang-Min; LI, Yah-Ming; ZE NG, Long-Mei

    2001-01-01

    A novel lanntanoid lactone (1) was first isolated fron the Alga Hypnen cerriconis collected from the Xisha Islands in theSouth China Sea. The structure of 1 was determined on spectral evidence as 5a-tansta-8-en-3β,22ζ-dihydroxy-22 (R), 24(S)-lactone.

  1. The formation mechanism of lactones in Gouda cheese

    NARCIS (Netherlands)

    Alewijn, M.; Smit, B.; Sliwinski, E.L.; Wouters, J.T.M.

    2007-01-01

    Lactones are fat-derived aroma compounds, but the formation mechanism of these compounds during ripening of Gouda cheese is unknown. Both enzymatic and chemical formation pathways were investigated in this study. Lactone formation from milk triglycerides or free fatty acids by lactic acid bacteria

  2. Crystal Structure of Homoserine Transacetylase from Haemophilus Influenzae Reveals a New Family of alpha/beta-Hydrolases

    Energy Technology Data Exchange (ETDEWEB)

    Mirza,I.; Nazi, I.; Korczynska, M.; Wright, G.; Berghuis, A.

    2005-01-01

    Homoserine transacetylase catalyzes one of the required steps in the biosynthesis of methionine in fungi and several bacteria. We have determined the crystal structure of homoserine transacetylase from Haemophilus influenzae to a resolution of 1.65 A. The structure identifies this enzyme to be a member of the alpha/beta-hydrolase structural superfamily. The active site of the enzyme is located near the end of a deep tunnel formed by the juxtaposition of two domains and incorporates a catalytic triad involving Ser143, His337, and Asp304. A structural basis is given for the observed double displacement kinetic mechanism of homoserine transacetylase. Furthermore, the properties of the tunnel provide a rationale for how homoserine transacetylase catalyzes a transferase reaction vs. hydrolysis, despite extensive similarity in active site architecture to hydrolytic enzymes.

  3. Acyl-CoA metabolism and partitioning

    DEFF Research Database (Denmark)

    Grevengoed, Trisha J; Klett, Eric L; Coleman, Rosalind A

    2014-01-01

    expression patterns and subcellular locations. Their acyl-CoA products regulate metabolic enzymes and signaling pathways, become oxidized to provide cellular energy, and are incorporated into acylated proteins and complex lipids such as triacylglycerol, phospholipids, and cholesterol esters. Their differing...... metabolic fates are determined by a network of proteins that channel the acyl-CoAs toward or away from specific metabolic pathways and serve as the basis for partitioning. This review evaluates the evidence for acyl-CoA partitioning by reviewing experimental data on proteins that are believed to contribute...... to acyl-CoA channeling, the metabolic consequences of loss of these proteins, and the potential role of maladaptive acyl-CoA partitioning in the pathogenesis of metabolic disease and carcinogenesis....

  4. Sesquiterpene lactones. XXIII. Isolation of sesquiterpene lactones from Centaurea L. species

    Directory of Open Access Journals (Sweden)

    Barbara Geppert

    2014-01-01

    Full Text Available Sesquiterpene lactones were isolated from 18 species or subspecies of the genus Centaurea L.: salonitenolide (I was found in C. crithmifolia Vis., C. friderici Vis., C, paniculata L., C. calcitrapa L., C. pontica Prodan et E. L' Nyarady, C. eriophora L., C. alba L. subsp. deusta (Ten. Nyman, C. alba L. subsp. caliacrae (Prodan Dostal and C. weldeniana Reichenb.; cnicin (II was found in: C. vallesiaca (DC. Jordan, C. calcitrapa L., C. aspera L. subsp. aspera, C. sphaerocephala L. subsp. lusitanica (Boiss. et Reuter Nyman, C. sulphurea Willd., C. eriophora L. and C. rocheliana (Heuffel Dostal; cynaropicrin (III was detected in C. debeauxii Gren. et Gordon subsp. thuillieri Dostal; acroptillin (V, repin (VI and janerin (VII in C. bella Trautv. Other unidentified sesquiterpene lactones were also found to be present in the examined plants.

  5. Design and synthesis of protein kinase C epsilon selective diacylglycerol lactones (DAG-lactones).

    Science.gov (United States)

    Ann, Jihyae; Yoon, Suyoung; Baek, Jisoo; Kim, Da Hye; Lewin, Nancy E; Hill, Colin S; Blumberg, Peter M; Lee, Jeewoo

    2015-01-27

    DAG-lactones afford a synthetically accessible, high affinity platform for probing structure activity relationships at the C1 regulatory domain of protein kinase C (PKC). Given the central role of PKC isoforms in cellular signaling, along with their differential biological activities, a critical objective is the design of isoform selective ligands. Here, we report the synthesis of a series of DAG-lactones varying in their side chains, with a particular focus on linoleic acid derivatives. We evaluated their selectivity for PKC epsilon versus PKC alpha both under standard lipid conditions (100% phosphatidylserine, PS) as well as in the presence of a nuclear membrane mimetic lipid mixture (NML). We find that selectivity for PKC epsilon versus PKC alpha tended to be enhanced in the presence of the nuclear membrane mimetic lipid mixture and, for our lead compound, report a selectivity of 32-fold.

  6. Sesquiterpene lactones. XXXVI. Sesquiterpene lactones in several subgenera of the genus Centaurea L.

    OpenAIRE

    Gerard Nowak; Miroslaw Holub; Miloš Buděšĺnský

    2014-01-01

    The occurrence of both known and new sesquiterpene lactones was determined in six species classified in different subgenera of Centaurea L. Chlorojanerin, cynaropicrin and janerin were isolated from C. phaeopappoides Bordz. and C. thracica (Janka) Hayek. C. marschalliana Spreng. was found to contain acroptilin, chlorojanerin, cebellin D and janerin while C. adjarica Alb. had repin, acroptilin, chlorojanerin, centaurepensin, janerin, repidiolide, cebellin D, E, F and L A new, hitherto underscr...

  7. Systemic allergic dermatitis caused by sesquiterpene lactones

    DEFF Research Database (Denmark)

    Paulsen, Evy

    2017-01-01

    Patients with Compositae sensitization are routinely warned against the ingestion of vegetables, spices, teas and herbal remedies from this family of plants. The evidence for the occurrence of systemic allergic dermatitis caused by sesquiterpene lactone-containing plants is mostly anecdotal...... and based on statements from patients rather than scientific data. However, a few clinical reports on accidental sensitization and exposure and oral challenge prove the existence of this kind of reaction, most convincingly for strong contact allergens such as costunolide in bay leaves, and less so for weak...... allergens such as those of lettuce. Other Compositae species suspected of causing systemic reactions are artichoke, mugwort, yarrow, dandelion, feverfew, and elecampane. Some Compositae vegetables and teas, such as lettuce and chamomile tea, may induce systemic reactions through both humoral and cell...

  8. Cynaratriol, a sesquiterpene lactone from Centaurea musimomum

    Directory of Open Access Journals (Sweden)

    Matías López-Rodríguez

    2009-08-01

    Full Text Available The title compound [systematic name: 3,8-dihydroxy-3-(hydroxymethyl-9-methyl-6-methylenedecahydroazuleno[4,5-b]furan-2(3H-one], C15H22O5, is a sesquiterpene lactone showing the typical tricyclic guaianolide skeleton which has been isolated, together with other related metabolites, from the plant Centaurea musimomum. The present study confirms the molecular structure, assigned by 1H NMR and MS spectroscopy, as well as the the 11β-hydroxymethyl, 3β-hydroxy and 4α-methyl stereochemistry. The crystal structure is built through a network of O—H...O hydrogen bonds involving the three hydroxyl groups that are present in the molecular skeleton.

  9. Trichodermaerin: a diterpene lactone from Trichoderma asperellum

    Directory of Open Access Journals (Sweden)

    Suchada Chantrapromma

    2014-04-01

    Full Text Available The title compound, C20H28O3, known as `trichodermaerin' [systematic name: (4E-4,9,15,16,16-pentamethyl-6-oxatetracyclo[10.3.1.01,10.05,9]hexadec-4-ene-7,13-dione], is a diterpene lactone which was isolated from Trichoderma asperellum. The structure has a tetracycic 6–5–7–5 ring system, with the cyclohexanone ring adopting a twisted half-chair conformation and the cyclopentane ring adopting a half-chair conformation, whereas the cycloheptene and tetrahydrofurananone rings are in chair and envelope (with the methyl-substituted C atom as the flap conformations, respectively. The three-dimensional architecture is stabilized by C—H...O interactions.

  10. Trichodermaerin: a diterpene lactone from Trichoderma asperellum

    Science.gov (United States)

    Chantrapromma, Suchada; Jeerapong, Chotika; Phupong, Worrapong; Quah, Ching Kheng; Fun, Hoong-Kun

    2014-01-01

    The title compound, C20H28O3, known as ‘trichodermaerin’ [systematic name: (4E)-4,9,15,16,16-penta­methyl-6-oxa­tetra­cyclo­[10.3.1.01,10.05,9]hexa­dec-4-ene-7,13-dione], is a diterpene lactone which was isolated from Trichoderma asperellum. The structure has a tetra­cycic 6–5–7–5 ring system, with the cyclo­hexa­none ring adopting a twisted half-chair conformation and the cyclo­pentane ring adopting a half-chair conformation, whereas the cyclo­heptene and tetra­hydro­furan­anone rings are in chair and envelope (with the methyl-substituted C atom as the flap) conformations, respectively. The three-dimensional architecture is stabilized by C—H⋯O inter­actions. PMID:24826124

  11. Dehydroleucodin: a guaiane-type sesquiterpene lactone

    Directory of Open Access Journals (Sweden)

    Horacio A. Priestap

    2011-12-01

    Full Text Available Dehydroleucodin [systematic name: (1S,6S,2R-9,13-dimethyl-5-methylene-3-oxatricyclo[8.3.0.02,6]trideca-9,12-diene-4,11-dione], C15H16O3, is a guanolide isolated from Artemisia douglasiana. The fused-ring system contains a seven-membered ring that adopts a chair conformation, a fused planar cyclopentenone ring and a five-membered lactone ring fused in envelope conformation. The absolute structure determined by X-ray analysis agrees with that previously assigned to this compound by NMR studies [Bohlmann & Zdero (1972. Tetrahedron Lett. 13, 621–624] and also with that of leucodine, a closely related guaianolide [Martinez et al. (1988. J. Nat. Prod. 51, 221–228].

  12. Detection of the quorum sensing signal molecule N-Dodecanoyl-DL-homoserine lactone below 1 nanomolarconcentrations using surface enhanced Raman spectroscopy

    DEFF Research Database (Denmark)

    Claussen, Anetta; Abdali, Salim; Berg, Rolf W.;

    2013-01-01

    To the best of our knowledge we here for the first time demonstrate surface enhanced Raman spectroscopy (SERS) to detect a quorum sensing (QS) signal molecule below 1 nM concentration in both ultrapure water and under physiological conditions. Based on our results, SERS shows promise as a highly...

  13. Immunization with 3-oxododecanoyl-L-homoserine lactone-r-PcrV conjugate enhances survival of mice against lethal burn infections caused by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Isar Dejban Golpasha

    2015-05-01

    Full Text Available Quorum Sensing and type III secretion system play an important role in the virulence of Pseudomonas (P. aeruginosa in burn wound infections. We aimed to explore the feasibility of using 3-oxo-C12-HSL-r-PcrV conjugate as a candidate vaccine against P. aeruginosa caused infections. 3-oxo-C12-HSL-r-PcrV conjugate was prepared and used for immunization of mice (10 μg, subcutaneous, three times, at 2-week intervals. Mice were divided into five groups: I: PcrV; II: 3-oxo-C12-HSL-r-PcrV (10 μg; III: 3-oxo-C12-HSL-r-PcrV (20 μg; IV: 3-oxo-C12-HSL; and V: PBS receiving groups.  After each shot of immunization, total and isotype antibody responses against corresponding antigen were measured to determine the immunization efficacy. One month after the last immunization, all groups were burned and challenged subeschar with P. aeruginosa PAO1. Survival rate and bacterial quantity in the skin and internal organs (liver and spleen were evaluated 25-hr after burn infection. Immunization with 3-oxo-C12-HSL-r-PcrV significantly increased total IgG and specific subclass antibodies (IgG1, IgG2a, IgG2b, and IgM in the serum of the groups II and III compared to the control group (p<0.001. While all the control mice (PBS injected group died within 2 days after bacterial challenge, 64% of the group I, 78% of group II, and 86% of group III, survived within 14 days after challenge. Interestingly, bacterial burden in the liver and spleen of 3-oxo-C12-HSL-r-PcrV injected group (III was significantly lower than the control group (p<0.001.  The present study proposed two-component vaccine to inhibit Pseudomonas infections in burned mouse. 

  14. Quorum Sensing Activity of Mesorhizobium sp. F7 Isolated from Potable Water

    Directory of Open Access Journals (Sweden)

    Pei-Ling Yong

    2014-01-01

    Full Text Available We isolated a bacterial isolate (F7 from potable water. The strain was identified as Mesorhizobium sp. by 16S rDNA gene phylogenetic analysis and screened for N-acyl homoserine lactone (AHL production by an AHL biosensor. The AHL profile of the isolate was further analyzed using high resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS which confirmed the production of multiple AHLs, namely, N-3-oxo-octanoyl-L-homoserine lactone (3-oxo-C8-HSL and N-3-oxo-decanoyl-L-homoserine lactone (3-oxo-C10-HSL. These findings will open the perspective to study the function of these AHLs in plant-microbe interactions.

  15. Quorum Sensing Activity of Enterobacter asburiae Isolated from Lettuce Leaves

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2013-10-01

    Full Text Available Bacterial communication or quorum sensing (QS is achieved via sensing of QS signaling molecules consisting of oligopeptides in Gram-positive bacteria and N-acyl homoserine lactones (AHL in most Gram-negative bacteria. In this study, Enterobacteriaceae isolates from Batavia lettuce were screened for AHL production. Enterobacter asburiae, identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS was found to produce short chain AHLs. High resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS analysis of the E. asburiae spent supernatant confirmed the production of N-butanoyl homoserine lactone (C4-HSL and N–hexanoyl homoserine lactone (C6-HSL. To the best of our knowledge, this is the first report of AHL production by E. asburiae.

  16. Quorum sensing activity of Mesorhizobium sp. F7 isolated from potable water.

    Science.gov (United States)

    Yong, Pei-Ling; Chan, Kok-Gan

    2014-01-01

    We isolated a bacterial isolate (F7) from potable water. The strain was identified as Mesorhizobium sp. by 16S rDNA gene phylogenetic analysis and screened for N-acyl homoserine lactone (AHL) production by an AHL biosensor. The AHL profile of the isolate was further analyzed using high resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS) which confirmed the production of multiple AHLs, namely, N-3-oxo-octanoyl-L-homoserine lactone (3-oxo-C8-HSL) and N-3-oxo-decanoyl-L-homoserine lactone (3-oxo-C10-HSL). These findings will open the perspective to study the function of these AHLs in plant-microbe interactions.

  17. Stability-increasing effects of anthocyanin glycosyl acylation.

    Science.gov (United States)

    Zhao, Chang-Ling; Yu, Yu-Qi; Chen, Zhong-Jian; Wen, Guo-Song; Wei, Fu-Gang; Zheng, Quan; Wang, Chong-De; Xiao, Xing-Lei

    2017-01-01

    This review comprehensively summarizes the existing knowledge regarding the chemical implications of anthocyanin glycosyl acylation, the effects of acylation on the stability of acylated anthocyanins and the corresponding mechanisms. Anthocyanin glycosyl acylation commonly refers to the phenomenon in which the hydroxyl groups of anthocyanin glycosyls are esterified by aliphatic or aromatic acids, which is synthetically represented by the acylation sites as well as the types and numbers of acyl groups. Generally, glycosyl acylation increases the in vitro and in vivo chemical stability of acylated anthocyanins, and the mechanisms primarily involve physicochemical, stereochemical, photochemical, biochemical or environmental aspects under specific conditions. Additionally, the acylation sites as well as the types and numbers of acyl groups influence the stability of acylated anthocyanins to different degrees. This review could provide insight into the optimization of the stability of anthocyanins as well as the application of suitable anthocyanins in food, pharmaceutical and cosmetic industries.

  18. Simultaneous Determination of Flavonols and Terpene Lactones in ...

    African Journals Online (AJOL)

    ... Flavonols and Terpene. Lactones in Beagle Dog Plasma by Ultra-Performance ... International Pharmaceutical Abstract, Chemical Abstracts, Embase, Index Copernicus, EBSCO, African ..... Extracts: A Review of the Pharmacokinetics of the.

  19. Diterpene lactones with labdane, halimane and clerodane frameworks.

    Science.gov (United States)

    Silva, Lúcia; Gomes, Arlindo C; Rodilla, Jesus M L

    2011-04-01

    The labdane, halimane and clerodane type diterpenoids are compounds that have been isolated in plants of several families. These molecules and their derivatives with a lactone group on the side chain or on the decaline system, have a great interest because of their biological properties as insect antifeedant, antiviral, cytotoxic and trypanocidal. The scope of this review is lactones diterpenoids with labdane, halimane and clerodane frameworks.

  20. Sesquiterpene lactones. XXXVI. Sesquiterpene lactones in several subgenera of the genus Centaurea L.

    Directory of Open Access Journals (Sweden)

    Gerard Nowak

    2014-01-01

    Full Text Available The occurrence of both known and new sesquiterpene lactones was determined in six species classified in different subgenera of Centaurea L. Chlorojanerin, cynaropicrin and janerin were isolated from C. phaeopappoides Bordz. and C. thracica (Janka Hayek. C. marschalliana Spreng. was found to contain acroptilin, chlorojanerin, cebellin D and janerin while C. adjarica Alb. had repin, acroptilin, chlorojanerin, centaurepensin, janerin, repidiolide, cebellin D, E, F and L A new, hitherto underscribed cebellin J quaianolide was found in C. bella Trautv. and another germacranolide, 3α, 15-dihydroxycostunolide was found in C. sphaerocephala subsp. lusitanica (Boiss. et Reuter Nyman.

  1. Acyl-coenzyme A organizes laterally in membranes and is recognized specifically by acyl-coenzyme A binding protein

    DEFF Research Database (Denmark)

    Cohen Simonsen, A; Bernchou Jensen, U; Færgeman, Nils J.

    2003-01-01

    and that ACBP may bind and desorb membrane-bound acyl-CoA via a partly unknown mechanism. Following incubation with acyl-CoA, it is shown that ACBP is able to reverse the formation of acyl-CoA aggregates and to associate peripherally with acyl-CoA on the membrane surface. Our microscopic results point...

  2. Catalytic Acylation of Anisole over Some Zeolites

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    4-Methoxyacetophenone(4-MAP) was synthesized by the acylation of anisole with acetic anhydride in the presence of HY zeolite.The addition of an appropriate amount of some solvent such as dichloromethane,chloroform,carbon disulfide or chlorobenzene to the reaction system can improve the yield of the acylated product to a certain extent.HY zeolite used can be recovered,and reused after being regenerated,obtaining almost the same yield of 4-MAP as the fresh zeolite.

  3. Acylation of Glucagon-like peptide-2

    DEFF Research Database (Denmark)

    Trier, Sofie; Linderoth, Lars; Bjerregaard, Simon;

    2014-01-01

    These results show that membrane interactions play a prominent role during intestinal translocation of an acylated peptide. Acylation benefits permeation for shorter and medium chains due to increased membrane interactions, however, for longer chains insertion in the membrane becomes dominant and...... and hinders translocation, i.e. the peptides get 'stuck' in the cell membrane. Applying a transcellular absorption enhancer increases the dynamics of membrane insertion and detachment by fluidizing the membrane, thus facilitating its effects primarily on membrane associated peptides....

  4. Fatty acyl-CoA reductase

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, Steven E.; Somerville, Chris R.

    1998-12-01

    The present invention relates to bacterial enzymes, in particular to an acyl-CoA reductase and a gene encoding an acyl-CoA reductase, the amino acid and nucleic acid sequences corresponding to the reductase polypeptide and gene, respectively, and to methods of obtaining such enzymes, amino acid sequences and nucleic acid sequences. The invention also relates to the use of such sequences to provide transgenic host cells capable of producing fatty alcohols and fatty aldehydes.

  5. Homoserine as an Aspartic Acid Precursor for Synthesis of Proteoglycan Glycopeptide Containing Aspartic Acid and a Sulfated Glycan Chain.

    Science.gov (United States)

    Yang, Weizhun; Ramadan, Sherif; Yang, Bo; Yoshida, Keisuke; Huang, Xuefei

    2016-12-02

    Among many hurdles in synthesizing proteoglycan glycopeptides, one challenge is the incorporation of aspartic acid in the peptide backbone and acid sensitive O-sulfated glycan chains. To overcome this, a new strategy was developed utilizing homoserine as an aspartic acid precursor. The conversion of homoserine to aspartic acid in the glycopeptide was successfully accomplished by late stage oxidation using (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) and bis(acetoxy)iodobenzene (BAIB). This is the first time that a glycopeptide containing aspartic acid and an O-sulfated glycan was synthesized.

  6. Muoniated acyl and thioacyl radicals

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, Iain [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Brodovitch, Jean-Claude [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Ghandi, Khashayar [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada); Percival, Paul W. [TRIUMF and Department of Chemistry, 8888 University Drive, Simon Fraser University, Burnaby B.C., V5A 1S6 (Canada)]. E-mail: percival@sfu.ca

    2006-03-31

    The product of the reaction of muonium with tert-butylisocyanate was previously assigned as the muoniated tert-butylaminyl radical (I. McKenzie, J.-C. Brodovitch, K. Ghandi, S. Kecman, P. W. Percival, Physica B 326 (2003) 76). This assignment is incorrect since the muon and {sup 14}N hyperfine-coupling constants (hfcc) of this radical would have the opposite sign, which is in conflict with the experimental results. The radical is now reassigned as the muoniated N-tert-butylcarbamoyl radical, based on the similarities between the experimental muon and {sup 14}N hfcc and hfcc calculated at the UB3LYP/6-311G(d,p)//UB3LYP/EPR-III level. The large zero-point energy in the N-Mu bond results in the dissociation barrier of the muoniated N-tert-butylcarbamoyl radical being above the combined energy of the reactants, in contrast to the N-tert-butylcarbamoyl radical where the dissociation barrier lies below the combined energy of the reactants. The reaction of muonium with tert-butylisothiocyanate produced both conformers of the muoniated N-tert-butylthiocarbamoyl radical and their assignment was based on the similarities between the experimental and calculated muon hfcc. These are the first acyl and thioacyl radicals to be directly detected by muon spin spectroscopy.

  7. Seasonal variation in sesquiterpene lactone concentration and composition of forage chicory (Cichorium intybus L.) cultivars

    Science.gov (United States)

    Chicory (Cichorium intybus L.) herbage contains sesquiterpene lactones that are believed to help control gastrointestinal nematodes in small ruminants. Because the anthelmintic effect could be related to both total sesquiterpene lactone concentration and the proportions of the principal constituent...

  8. Bioorthogonal metabolic labelling with acyl-CoA reporters : targeting protein acylation

    NARCIS (Netherlands)

    Ourailidou, Maria E.; Zwinderman, Martijn R.H.; Dekker, Frans

    2016-01-01

    Protein acylation is an abundant post-translational modification with a pivotal role in a plethora of biological processes. To date, metabolic labelling with functionalized precursors of acyl-CoA and subsequent bio-orthogonal ligation to a complementary detection tag has offered an attractive approa

  9. Cytotoxic sesquiterpene lactones and other constituents of Centaurea omphalotricha

    Energy Technology Data Exchange (ETDEWEB)

    Kolli, El Hadj; Leon, Francisco; Benayache, Samir, E-mail: jfleon@ipna.csic.es, E-mail: sbenayache@yahoo.com [Laboratoire de Valorisation des Ressources Naturelles et Synthese de Substances Bioactives, Equipe Associee a l' A.N.D.R.S., Universite Mentouri, Constantine (Algeria); Benayache, Fadila [Laboratoire de Phytochimie et Analyses Physico-Chimiques et Biologiques, Universite Mentouri, Constantine (Algeria); Estevez, Sara; Quintana, Jose; Estevez, Francisco [Departamento de Bioquimica, Unidad Asociada al CSIC, Facultad de Ciencias de la Salud, Universidad de Las Palmas de Gran Canaria (Spain); Instituto Canario de Investigacion del Cancer, Las Palmas de Gran Canaria, Gran Canaria (Spain); Brouard, Ignacio; Bermejo, Jaime [Instituto de Productos Naturales y Agrobiologia, CSIC, La Laguna, Tenerife (Spain)

    2012-05-15

    Phytochemical research of the aerial parts of Centaurea omphalotricha led to the isolation of three new sesquiterpene lactones, 4'-acetyl cynaropicrin, 4'-acetyl cebellin F and 15-acetyl dehydromelitensin, together with twelve known compounds, seven sesquiterpene lactones, two isoprenoids and three flavonoids. The structures of the new compounds were elucidated by means of extensive 1D and 2D NMR, and MS, and by comparison with reported data in the literature. The effect of sesquiterpene lactones on the viability of the human tumor cell lines HL-60 and U937 was also investigated and 3-acetyl cynaropicrin, and 4'-acetyl cynaropicrin were found to be the most cytotoxic compounds against human leukemia cells with an IC{sub 50} values of 2.0 =- 0.9 and 5.1 +- 0.4 {mu}mol L{sup -1}, respectively. (author)

  10. Relationship between Menthiafolic Acid and Wine Lactone in Wine.

    Science.gov (United States)

    Giaccio, Joanne; Curtin, Chris D; Sefton, Mark A; Taylor, Dennis K

    2015-09-23

    Menthiafolic acid (6-hydroxy-2,6-dimethylocta-2,7-dienoic acid, 2a) was quantified by GC-MS in 28 white wines, 4 Shiraz wines, and for the first time in 6 white grape juice samples. Menthiafolic acid was detected in all but one of the wine samples at concentrations ranging from 26 to 342 μg/L and in the juice samples from 16 to 236 μg/L. Various model fermentation experiments showed that some menthiafolic acid in wine could be generated from the grape-derived menthiafolic acid glucose ester (2b) during alcoholic and malolactic fermentation. Samples containing high concentrations of menthiafolic acid were also analyzed by enantioselective GC-MS and were shown to contain this compound in predominantly the (S)-configuration. Enantioselective analysis of wine lactone (1) in one of these samples, a four-year-old Chardonnay wine showed, for the first time, the presence of the 3R,3aR,7aS isomer of wine lactone (1b), which is the enantiomer of the form previously reported as the sole isomer present in young wine samples. The weakly odorous 3R,3aR,7aS 1b form comprised 69% of the total wine lactone in the sample. On the basis of the enantioselectivity of the hydrolytic conversion of menthiafolic acid to wine lactone at pH 3.0 determined previously and the relative proportions of (R)- and (S)-menthiafolic acid in the Chardonnay wine, the predicted ratio of wine lactone enantiomers that would be formed from hydrolysis at ambient temperature of the menthiafolic acid present in this wine was close to the ratio measured, which was consistent with menthiafolic acid being the major or sole precursor to wine lactone in this sample.

  11. Natural occurrence, biological activities and synthesis of eight-, nine-, and eleven-membered ring lactones

    Directory of Open Access Journals (Sweden)

    Helena M. C. Ferraz

    2008-01-01

    Full Text Available The natural occurrence, biological activities and synthetic approaches to natural eight-, nine-, and eleven-membered lactones is reviewed. These medium ring lactones are grouped according to ring size, and their syntheses are discussed. The structures of some natural products early identified as medium-ring lactones were revised after total synthesis.

  12. Catalytic Acylation of Ethylidenecyclohexane over Zeolite Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Some environmentally friendly catalysts such as HY and H-β zeolites,various cation-exchanged β zeolites,and some other solids have been used in the acylation reaction of ethylidenecyclohexane with acetic anhydride at room temperature to synthesize 3-(1-cyclohexenyl)-2-butanone instead of conventional catalysts.The effect of the amount of HY zeolite used on the acylation reaction was investigated.The yield of the acylated product was 72% in the case of n(ethylidenecyclohexane)∶n(acetic anhydride)∶m(HY zeolite)=1 mmol∶10 mmol∶0.100 g,reaction temperature:25 ℃,and reaction time:2 h.The regenerated HY zeolite showed almost the same catalytic activity as the fresh zeolite.

  13. Acyl-coenzyme A binding protein, ACBP

    DEFF Research Database (Denmark)

    Kragelund, Birthe Brandt; Knudsen, J.; Poulsen, Flemming

    1999-01-01

    Acyl-coenzyme A binding proteins are known from a large group of eukaryote species and to bind a long chain length acyl-CoA ester with very high affinity. Detailed biochemical mapping of ligand binding properties has been obtained as well as in-depth structural studies on the bovine apo-protein...... and of the complex with palmitoyl-CoA using NMR spectroscopy. In the four a-helix bundle structure, a set of 21 highly conserved residues present in more that 90% of all known sequences of acyl-coenzyme A binding proteins constitutes three separate mini-cores. These residues are predominantly located at the helix......-helix interfaces. From studies of a large set of mutant proteins the role of the conserved residues has been related to structure, function, folding and stability....

  14. Acyl-coenzyme A binding protein (ACBP)

    DEFF Research Database (Denmark)

    Kragelund, B B; Knudsen, J; Poulsen, F M

    1999-01-01

    and of the complex with palmitoyl-CoA using NMR spectroscopy. In the four alpha-helix bundle structure, a set of 21 highly conserved residues present in more that 90% of all known sequences of acyl-coenzyme A binding proteins constitutes three separate mini-cores. These residues are predominantly located......Acyl-coenzyme A binding proteins are known from a large group of eukaryote species and to bind a long chain length acyl-CoA ester with very high affinity. Detailed biochemical mapping of ligand binding properties has been obtained as well as in-depth structural studies on the bovine apo-protein...... at the helix-helix interfaces. From studies of a large set of mutant proteins the role of the conserved residues has been related to structure, function, folding and stability....

  15. In silico prediction of acyl glucuronide reactivity

    Science.gov (United States)

    Potter, Tim; Lewis, Richard; Luker, Tim; Bonnert, Roger; Bernstein, Michael A.; Birkinshaw, Timothy N.; Thom, Stephen; Wenlock, Mark; Paine, Stuart

    2011-11-01

    Drugs and drug candidates containing a carboxylic acid moiety, including many widely used non-steroidal anti-inflammatory drugs (NSAIDs) are often metabolized to form acyl glucuronides (AGs). NSAIDs such as Ibuprofen are amongst the most widely used drugs on the market, whereas similar carboxylic acid drugs such as Suprofen have been withdrawn due to adverse events. Although the link between these AG metabolites and toxicity is not proven, there is circumstantial literature evidence to suggest that more reactive acyl glucuronides may, in some cases, present a greater risk of exhibiting toxic effects. We wished therefore to rank the reactivity of potential new carboxylate-containing drug candidates, and performed kinetic studies on synthetic acyl glucuronides to benchmark our key compounds. Driven by the desire to quickly rank the reactivity of compounds without the need for lengthy synthesis of the acyl glucuronide, a correlation was established between the degradation half-life of the acyl glucuronide and the half life for the hydrolysis of the more readily available methyl ester derivative. This finding enabled a considerable broadening of chemical property space to be investigated. The need for kinetic measurements was subsequently eliminated altogether by correlating the methyl ester hydrolysis half-life with the predicted 13C NMR chemical shift of the carbonyl carbon together with readily available steric descriptors in a PLS model. This completely in silico prediction of acyl glucuronide reactivity is applicable within the earliest stages of drug design with low cost and acceptable accuracy to guide intelligent molecular design. This reactivity data will be useful alongside the more complex additional pharmacokinetic exposure and distribution data that is generated later in the drug discovery process for assessing the overall toxicological risk of acidic drugs.

  16. Natural Sesquiterpene Lactones Induce Oxidative Stress in Leishmania mexicana

    Directory of Open Access Journals (Sweden)

    Patricia Barrera

    2013-01-01

    Full Text Available Leishmaniasis is a worldwide parasitic disease, caused by monoflagellate parasites of the genus Leishmania. In the search for more effective agents against these parasites, the identification of molecular targets has been attempted to ensure the efficiency of drugs and to avoid collateral damages on the host’s cells. In this work, we have investigated some of the mechanisms of action of a group of natural sesquiterpene lactones that are effective against Leishmania mexicana mexicana promastigotes. We first observed that the antiproliferative effect of mexicanin I (Mxc, dehydroleucodine (DhL, psilostachyin (Psi, and, at lesser extent, psilostachyin C (Psi C is blocked by 1.5 mM reduced glutathione. The reducing agent was also able to reverse the early effect of the compounds, suggesting that lactones may react with intracellular sulfhydryl groups. Moreover, we have shown that all the sesquiterpene lactones, except Psi C, significantly decreased the endogenous concentration of glutathione within the parasite. Consistent with these findings, the active sesquiterpene lactones increased between 2.7 and 5.4 times the generation of ROS by parasites. These results indicate that the induction of oxidative stress is at least one of the mechanisms of action of DhL, Mxc, and Psi on parasites while Psi C would act by another mechanism.

  17. A New Sesquiterpene Lactones Glucoside from Notoseris psilolepis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new sesquiterpene lactone glucoside, notoserolide C (1), was isolated from the whole plant of Notoseris psilolepis Shih. By means of spectral analysis including MS, NMR (1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC) and X-ray diffraction, the structure of notoserolide C was established as cichorioside B angelate.

  18. Toward understanding how the lactone moiety of discodermolide affects activity.

    Science.gov (United States)

    Shaw, Simon J; Sundermann, Kurt F; Burlingame, Mark A; Myles, David C; Freeze, B Scott; Xian, Ming; Brouard, Ignacio; Smith, Amos B

    2005-05-11

    A series of simplified discodermolide analogues have been designed and synthesized in an attempt to understand the role of the lactone ring. These synthetic efforts have led to an unsubstituted butyrolactone 9 being generated, which shows improved activity over the natural product.

  19. Synthesis of macrocyclic lactones with methoxysulfonyl side chain

    Institute of Scientific and Technical Information of China (English)

    Chuan Jin Hou; Xiao Mei Liang; Jing Ping Wu; Dao Quan Wang

    2008-01-01

    Two representative macrocyclic lactones with methoxysulfonyl side chain (5a and 5b) were synthesized employing Michael addition with acrolein and ring enlargement as the key steps,starting from potassium a-oxocycloalkylsulfonates (1) in total yields of 45 and 57%,respectively.

  20. Sesquiterpene lactone glycosides from the roots of Ferula varia.

    Science.gov (United States)

    Kurimoto, Shin-ichiro; Suzuki, Kyoko; Okasaka, Mamoru; Kashiwada, Yoshiki; Kodzhimatov, Olimjion Kakhkharovich; Takaishi, Yoshihisa

    2012-01-01

    Seven new sesquiterpene lactone glycosides (1-7) were isolated from the H2O-soluble fraction from the MeOH extract of the roots of Ferula varia. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of compounds 1 and 2 were determined by modified Mosher's method.

  1. Statin Lactonization by Uridine 5'-Diphospho-glucuronosyltransferases (UGTs)

    NARCIS (Netherlands)

    Schirris, T.J.J.; Ritschel, T.; Bilos, A.; Smeitink, J.A.M.; Russel, F.G.M.

    2015-01-01

    Statins are cholesterol-lowering drugs that have proven to be effective in lowering the risk of major cardiovascular events. Although well tolerated, statin-induced myopathies are the most common side effects. Compared to their pharmacologically active acid form, statin lactones are more potent indu

  2. Acyl-coenzyme A:cholesterol acyltransferases

    OpenAIRE

    Chang, Ta-Yuan; Li, Bo-Liang; Chang, Catherine C.Y.; Urano, Yasuomi

    2009-01-01

    The enzymes acyl-coenzyme A (CoA):cholesterol acyltransferases (ACATs) are membrane-bound proteins that utilize long-chain fatty acyl-CoA and cholesterol as substrates to form cholesteryl esters. In mammals, two isoenzymes, ACAT1 and ACAT2, encoded by two different genes, exist. ACATs play important roles in cellular cholesterol homeostasis in various tissues. This chapter summarizes the current knowledge on ACAT-related research in two areas: 1) ACAT genes and proteins and 2) ACAT enzymes as...

  3. Chemoenzymatic synthesis and properties of novel lactone-type anionic surfactants.

    Science.gov (United States)

    Mori, Keisuke; Matsumura, Shuichi

    2012-01-01

    Two series of lactone-type surfactants with and without a hexyl side chain were prepared by the cyclocondensation of dimethyl alkanedioates with unsaturated diols, such as cis-2-butene-1,4-diol and ricinoleyl alcohol, using a lipase, followed by the addition of hydrophilic 3-mercaptopropionic acid in the presence of triethylamine. The lactone-type surfactants showed clear cmc values and surface tension lowering in aqueous solution irrespective of the hexyl side chain. It was found that the cmc values of lactone-type surfactants were lower than that of typical anionics, e.g., sodium laurate, and the cmc value became lower with increasing size of the lactone ring. The adsorption area at the surface of the aqueous lactone-type surfactant solution was larger when compared to the corresponding non-lactone-type surfactants. Lactone-type surfactants without the hexyl side chain aggregated quickly, forming 3-10 nm micelles; on the other hand, lactone-type surfactants with the hexyl side chain formed significantly larger micelles. This is due to the steric hindrance of the hexyl group on the lactone ring. The solubilization ability of the lactone-type surfactants with a hexyl side chain was superior to those without a hexyl side chain. The lactone-type surfactants showed a high foaming power and low foaming stability. They were also biodegraded by activated sludge.

  4. Preferred Conformers of Non-Proteinogenic Amino Acids Homoserine and Homocysteine

    Science.gov (United States)

    Díez, Verónica; Rodríguez, Miguel A.; Mata, Santiago; Alonso, E. R.; Cabezas, Carlos; Alonso, José L.

    2016-06-01

    Vaporization of solid homoserine and homocysteine by laser ablation in combination with Fourier transform microwave spectroscopy techniques made possible the detection of their most stable structures in a supersonic expansion. All detected conformers have been identified through their rotational and 14N quadrupole coupling constants. They show hydrogen bonds linking the amino and carboxylic group through N-H\\cdot\\cdot\\cdotO=C (type I) or N\\cdot\\cdot\\cdotH-O (type II) interactions. In some of them there are additional hydrogen bonds established between the amino group and the hydroxyl/thiol groups in the gamma position. Entropic effects related to the side chain have been found to be significant in determining the most populated conformations.

  5. Organocatalytic Site-Selective Acylation of 10-Deacetylbaccatin III.

    Science.gov (United States)

    Yanagi, Masanori; Ninomiya, Ryo; Ueda, Yoshihiro; Furuta, Takumi; Yamada, Takeshi; Sunazuka, Toshiaki; Kawabata, Takeo

    2016-07-01

    Organocatalytic site-selective diversification of 10-deacetylbaccatin III, a key natural product for the semisynthesis of taxol, has been achieved. Various acyl groups were selectively introduced into the C(10)-OH of 10-deacetylbaccatin III. The C(10)-OH selective acylation was also applied to acylative site-selective dimerization of 10-deacetylbaccatin III to provide the structurally defined dimer.

  6. Over omzettingen van a-acyl-benzylcyanides

    NARCIS (Netherlands)

    Wajon, Jozef Franciscus Marie

    1956-01-01

    On heating of a-acetyl-benzylcyanide (II) with a mixture of acetic acid and sulphuric acid, 4, 6 - dimethyl - 3. 5 - diphenyl - pyridone - 2 (X V) is formed. This product is formed by condensation of the amide (XI) with the ketone (VII), both originating from the cyanide (II). With some other a-acyl

  7. Veronica: Acylated flavone glycosides as chemosystematic markers

    DEFF Research Database (Denmark)

    Albach, Dirk C.; Grayer, Renée J.; Kite, Geoffrey C.

    2005-01-01

    HPLC/DAD and LCeMS of an extract of Veronica spicata subgenus Pseudolysimachium, Plantaginaceae) revealed the presence of six 6-hydroxyluteolin glycosides acylated with phenolic acids, three of which are new compounds and which we called spicosides. A flavonoid survey of seven more species...

  8. Role of acylCoA binding protein in acylCoA transport, metabolism and cell signaling

    DEFF Research Database (Denmark)

    Knudsen, J; Jensen, M V; Hansen, J K;

    1999-01-01

    Long chain acylCoA esters (LCAs) act both as substrates and intermediates in intermediary metabolism and as regulators in various intracellular functions. AcylCoA binding protein (ACBP) binds LCAs with high affinity and is believed to play an important role in intracellular acylCoA transport...

  9. Acyl-CoA oxidase 1 is involved in γ-decalactone release from peach (Prunus persica) fruit.

    Science.gov (United States)

    Zhang, Liping; Li, Haiyan; Gao, Ling; Qi, Yujie; Fu, Wanyi; Li, Xiongwei; Zhou, Xiang; Gao, Qikang; Gao, Zhongshan; Jia, Huijuan

    2017-06-01

    γ-Decalactone accumulation in peach mesocarp was highly correlated with ACX enzyme activity and natural PpACX1 content. Adding the purified recombinant PpACX1 induced γ-decalactone biosynthesis in cultured mesocarp discs in vitro. Previous gene expression studies have implied that acyl coenzyme A oxidase (ACX) is related to lactones synthesis, the characteristic aroma compounds of peach. Here, we analysed the correlation between γ-decalactone content and ACX enzyme activity in mesocarp of five different types of fully ripe peach varieties. Furthermore, 'Hu Jing Mi Lu' ('HJ') and 'Feng Hua Yu Lu' ('YL'), which have strong aroma among them, at four ripening stages were selected to study the role of ACX in lactone biosynthesis. The result showed that γ-decalactone was the most abundant lactone compound. γ-Decalactone accumulation was highly correlated with ACX enzyme activity. Mass spectrometry (MS) showed that PpACX1 was the most abundant PpACX protein in fully ripe mesocarp of cv. 'HJ'. To further elucidate the function of the PpACX1 protein, the PpACX1 gene was heterologously expressed in a bacterial system and characterized in vitro. MS identification gave the molecular weight of the recombinant PpACX1 as 94.44 kDa and the coverage rate of the peptide segments was 47.3%. In cultured mesocarp discs in vitro, adding the purified recombinant PpACX1 and C16-CoA substrate induced the expected γ-decalactone biosynthesis. Using a sandwich ELISA based on mixed mono- and polyclonal antibodies against recombinant PpACX1, PpACX1 content in mesocarp was found to be highly correlated with γ-decalactone accumulation in mesocarp of five fully ripe varieties and four ripening stages of 'HJ' and 'YL'. This study revealed the vital function of PpACX1 in γ-decalactone biosynthesis in peach fruit.

  10. Lactonic Sophorolipids Increase Tumor Burden in Apcmin+/- Mice.

    Directory of Open Access Journals (Sweden)

    Breedge Callaghan

    Full Text Available Sophorolipids (SL are amphiphilic biosurfactant molecules consisting of a disaccharide sophorose with one fatty acid at the C1 position and optional acetylation at the C6'and C6" positions. They exist in a closed ring lactonic (LSL or open acidic (ASL structure Sophorolipids are produced in crude mixtures in economically viable amounts by the yeast Starmerella bombicola and used in a variety of consumer products. Varying levels of anti- proliferative and anti-cancer activity of crude sophorolipid mixtures are described in a number of tumor cell lines in vitro. However, significant inter-study variation exists in the composition of sophorolipid species as well as other biologically active compounds in these mixtures, which makes interpretation of in vitro and in vivo studies difficult. We produced a 96% pure C18:1 lactonic sophorolipid that dose-dependently reduces the viability of colorectal cancer, as well as normal human colonic and lung cell lines in vitro. Oral administration of vehicle-only; or lactonic sophorolipids (50 mg/kg for 70 days, to Apcmin+/- mice resulted in an increase in the number (55.5 ± 3.3 vs 70.50 ± 7.8: p < 0.05 and size (modal size 2mm vs 4mm of intestinal polyps. Lactonic administration resulted in a systematic effect via reduced hematocrit (49.5 ± 1.0 vs 28.2 ± 2.0 vs: p<0.03 and splenomegaly (0.56 ± 0.03g vs 0.71 ± 0.04g; p<0.01 confirming exacerbation of disease progression in this model.

  11. Natural Sesquiterpene Lactones Induce Oxidative Stress in Leishmania mexicana

    OpenAIRE

    Patricia Barrera; Valeria P Sülsen; Esteban Lozano; Mónica Rivera; María Florencia Beer; Carlos Tonn; Martino, Virginia S.; Sosa, Miguel A.

    2015-01-01

    Leishmaniasis is a worldwide parasitic disease, caused by monoflagellate parasites of the genus Leishmania. In the search for more effective agents against these parasites, the identification of molecular targets has been attempted to ensure the efficiency of drugs and to avoid collateral damages on the host’s cells. In this work, we have Investigated some of the mechanisms of action of a group of natural sesquiterpene lactones that are effective against Leishmania mexicana mexicana promasti...

  12. Cytotoxic sesquiterpene lactones from the aerial parts of Inula aucheriana.

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Gohari

    2015-06-01

    Full Text Available Inula aucheriana DC is a member of the family Asteraceae which is known to produce cytotoxic secondary metabolites noted as sesquiterpene lactones. In the present study, sesquiterpene lactones inuchinenolide B, 6-deoxychamissonolide (stevin and 14-acetoxy-1β,5α,7αH-4β-hydroxy-guai-9(10,11(13-dien-12,8α-olide were isolated from I. aucheriana. Inuchinenolide B and 14-acetoxy-1β,5α,7αH-4β-hydroxy-guai-9(10,11(13-dien-12,8α-olide were further evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide assay to demonstrate cytotoxic activity with IC50 values of (56.6, 19.0, (39.0, 11.8, and (55.7, 15.3 μg/mL against HepG-2, MCF-7 and A-549 cells, respectively. The cytotoxic activity of the two evaluated sesquiterpene lactones partly explains the cytotoxic activity that was previously observed for the extracts of Inula aucheriana. The isolated compounds could be further investigated in cancer research studies.

  13. In Vitro Antitumor Activity of Sesquiterpene Lactones from Lychnophora trichocarpha

    Directory of Open Access Journals (Sweden)

    D.A. Saúde-Guimarães

    2014-06-01

    Full Text Available The sesquiterpene lactones lychnopholide and eremantholide C were isolated from Lychnophora trichocarpha Spreng. (Asteraceae, which is a plant species native to the Brazilian Savannah or Cerrado and popularly known as arnica. Sesquiterpene lactones are known to present a variety of biological activities including antitumor activity. The present paper reports on the evaluation of the in vitro antitumor activity of lychnopholide and eremantholide C, in the National Cancer Institute, USA (NCI, USA, against a panel of 52 human tumor cell lines of major human tumors derived from nine cancer types. Lychnopholide disclosed significant activity against 30 cell lines of seven cancer types with IC100 (total growth concentration inhibition values between 0.41 µM and 2.82 µM. Eremantholide C showed significant activity against 30 cell lines of eight cancer types with IC100 values between 21.40 µM and 53.70 µM. Lychnopholide showed values of lethal concentration 50% (LC50 for 30 human tumor cell lines between 0.72 and 10.00 µM, whereas eremantholide C presented values of LC50 for 21 human tumor cell lines between 52.50 and 91.20 µM. Lychnopholide showed an interesting profile of antitumor activity. The α-methylene-γ-lactone present in the structure of lychnopholide, besides two α,β- unsaturated carbonyl groups, might be responsible for the better activity and higher cytotoxicity of this compound in relation to eremantholide C.

  14. Stereoselective synthesis of (+)-nephrosteranic acid, (+)-trans-cognac lactone, and (+)-trans-whisky lactone using a chiral cyclohexadienyl Ti compound.

    Science.gov (United States)

    Schleth, Florian; Vogler, Thomas; Harms, Klaus; Studer, Armido

    2004-09-01

    We present the stereoselective transfer of cyclohexadienyl from 3-metalated 1,4-cyclohexadienes to various aldehydes. Lewis-acid-mediated "allylation" of aldehydes by treatment with 3-silylated and 3-stannylated 1,4-cyclohexadienes could not be achieved with high diastereoselectivity. In contrast, cyclohexadienyl titanium compounds reacted with both aliphatic and aromatic aldehydes with good-to-excellent diastereoselectivities. Reaction of a chiral TADDOL-derived (TADDOL, 2,2-dimethyl-alpha,alpha,alpha',alpha'-tetraphenyl-1,3-dioxolandimethanol) cyclohexadienyl Ti derivative with various aldehydes led to the corresponding homoallylic alcohols with excellent diastereo- and enantioselectivities. Lower selectivities were obtained with chiral B-cyclohexadienyldiisopinocampheylborane. The 1,3-cyclohexadienes are very useful building blocks for the preparation of biologically important gamma-butyrolactones. Short efficient syntheses of (+)-nephrosteranic acid, (+)-trans-whisky lactone, and (+)-trans-cognac lactone by desymmetrization of 1,4-cyclohexadiene are described.

  15. Production d'arômes de type lactone par des levures

    OpenAIRE

    Alchihab, M.; Destain, J.; Aguedo, M.; Thonart, P.

    2010-01-01

    Production of aroma lactones by yeasts. Lactones are widely distributed in foods and beverages as aroma compounds. Their extraction from natural products is very expensive. Most of them can also be obtained in a chemical way, which is not well perceived by consumers. As an alternative, biotechnology proposes to use whole cells or enzymes to produce lactones by biotransformation or bioconversion of fatty acids. Different studies and patents have been conducted on that matter. In most cases, ye...

  16. Genome sequence of Phaeobacter caeruleus type strain (DSM 24564T), a surface-associated member of the marine Roseobacter clade

    OpenAIRE

    Beyersmann, Paul G.; Chertkov, Olga; Petersen, Jörn; Fiebig, Anne; Chen, Amy; Pati, Amrita; Ivanova, Natalia; Lapidus, Alla; Lynne A Goodwin; Chain, Patrick; Detter, John C.; Rohde, Manfred; Gronow, Sabine; Kyrpides, Nikos C; Woyke, Tanja

    2013-01-01

    In 2009 Phaeobacter caeruleus was described as a novel species affiliated with the marine Roseobacter clade, which, in turn, belongs to the class Alphaproteobacteria. The genus Phaeobacter is well known for members that produce various secondary metabolites. Here we report of putative quorum sensing systems, based on the finding of six N-acyl-homoserine lactone synthetases, and show that the blue color of P. caeruleus is probably due to the production of the secondary metabolite indigoidine. ...

  17. Bacterial Genome Engineering and Synthetic Biology: Combating Pathogens

    Science.gov (United States)

    2016-11-04

    AHL: N-acyl-L-homoserine lactone; CAI-1: Cholerae autoinducer-1; CDC: Centers for Disease Control and Prevention ; CRISPR: clustered regularly...Organization (WHO) and Centers for Disease Control and Prevention (CDC), there is an unprecedented increase in the occurrence of MDR infections...SB has enormous potential to develop biomedical therapies to prevent and treat diseases caused by bacterial infections. List of Abbreviations

  18. Silver-catalyzed one-pot synthesis of arylnaphthalene lactone natural products.

    Science.gov (United States)

    Foley, Patrick; Eghbali, Nicolas; Anastas, Paul T

    2010-05-28

    Naturally occurring arylnaphthalene lactone lignans have demonstrated a variety of valuable medicinal chemistry properties and have therefore been of continued interest to drug discovery research. Our group has demonstrated a silver-catalyzed one-pot synthesis of the arylnaphthalene lactone core using carbon dioxide, phenylpropargyl chloride, and phenylacetylene. This new approach has been employed in the synthesis of six arylnaphthalene lactone natural products: retrochinensin (1), justicidin B (2), retrojusticidin B (3), chinensin (4), justicidin E (5), and taiwanin C (6). Additionally, an arylnaphthalene lactone regioisomer was isolated (9), which we refer to as isoretrojusticidin B.

  19. Metabolism of 4-Hydroxy-7-oxo-5-heptenoic Acid (HOHA) Lactone by Retinal Pigmented Epithelial Cells.

    Science.gov (United States)

    Wang, Hua; Linetsky, Mikhail; Guo, Junhong; Yu, Annabelle O; Salomon, Robert G

    2016-07-18

    4-Hydroxy-7-oxo-5-heptenic acid (HOHA)-lactone is a biologically active oxidative truncation product released (t1/2 = 30 min at 37 °C) by nonenzymatic transesterification/deacylation from docosahexaenoate lipids. We now report that HOHA-lactone readily diffuses into retinal pigmented epithelial (RPE) cells where it is metabolized. A reduced glutathione (GSH) Michael adduct of HOHA-lactone is the most prominent metabolite detected by LC-MS in both the extracellular medium and cell lysates. This molecule appeared inside of ARPE-19 cells within seconds after exposure to HOHA-lactone. The intracellular level reached a maximum concentration at 30 min and then decreased with concomitant increases in its level in the extracellular medium, thus revealing a unidirectional export of the reduced GSH-HOHA-lactone adduct from the cytosol to extracellular medium. This metabolism is likely to modulate the involvement of HOHA-lactone in the pathogenesis of human diseases. HOHA-lactone is biologically active, e.g., low concentrations (0.1-1 μM) induce secretion of vascular endothelial growth factor (VEGF) from ARPE-19 cells. HOHA-lactone is also a precursor of 2-(ω-carboxyethyl)pyrrole (CEP) derivatives of primary amino groups in proteins and ethanolamine phospholipids that have significant pathological and physiological relevance to age-related macular degeneration (AMD), cancer, and wound healing. Both HOHA-lactone and the derived CEP can contribute to the angiogenesis that defines the neovascular "wet" form of AMD and that promotes the growth of tumors. While GSH depletion can increase the lethality of radiotherapy, because it will impair the metabolism of HOHA-lactone, the present study suggests that GSH depletion will also increase levels of HOHA-lactone and CEP that may promote recurrence of tumor growth.

  20. Regioselective enzymatic acylation of troxerutin in nonaqueous medium

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A series of monosubstituted troxerutin esters have been synthesized by enzyme-catalyzed regioselective acylation of troxerutin in nonaqueous medium.Using divinyl dicarboxylates(CH_2=CH-OOC-(CH_2)_n-COO-CH=CH_2,n = 2,3,4,7,8,11) featuring different chain length as acyl donors and alkaline protease from Bacillus subtilis as catalyst,troxerutin was regioselective acylated at B' ethoxyl group.The results indicated that the regioselectivity of the enzyme-catalyzed acylation was not affected by the chain lengt...

  1. Estrogen elevates the peak overnight production rate of acylated ghrelin.

    Science.gov (United States)

    Paulo, Remberto C; Brundage, Richard; Cosma, Mihaela; Mielke, Kristi L; Bowers, Cyril Y; Veldhuis, Johannes D

    2008-11-01

    Acylated ghrelin is the putatively bioactive GH secretagogue. Estradiol (E2) stimulates the synthesis rather than inhibits the metabolic clearance of acylated ghrelin. The study took place at an academic medical center. Healthy postmenopausal women participated. Interventions included prospectively randomized, double-blind separate-day iv infusions of saline or five graded doses of ghrelin in estrogen-deficient (n=12) and E2-supplemented (n=8) women. Metabolic clearance rate (MCR), volume of distribution, half-life, and secretion rate of acylated ghrelin were assessed. In pilot iv bolus ghrelin infusions, the median half-lives of acylated and total ghrelin were 21 and 36 min (Prate (638+/-12 slope units), 2) MCR of acylated ghrelin and ghrelin infusion rate (10+/-2.5 slope units), and 3) MCR and plasma concentration of acylated ghrelin (0.017+/-0.004 slope units). These data predict peak nighttime production rates of acylated ghrelin of 3.8+/-0.9 (E2) and 1.9+/-0.2 (no E2) ng/kg.min (P=0.039). Acylated ghrelin has a multifold larger distribution volume and MCR than total ghrelin. An estrogenic milieu augments synthesis and/or acylation of ghrelin peptide without altering its MCR.

  2. Plasma levels of acylated ghrelin in patients with functional dyspepsia

    Institute of Scientific and Technical Information of China (English)

    Yeon Soo Kim; Joon Seong Lee; Tae Hee Lee; Joo Young Cho; Jin Oh Kim; Wan Jung Kim; Hyun Gun Kim; Seong Ran Jeon; Hoe Su Jeong

    2012-01-01

    AIM:To investigate the relationship between plasma acylated ghrelin levels and the pathophysiology of functional dyspepsia.METHODS:Twenty-two female patients with functional dyspepsia and twelve healthy volunteers were recruited for the study.The functional dyspepsia patients were each diagnosed based on the Rome Ⅲ criteria.Eligible patients completed a questionnaire concerning the severity of 10 symptoms.Plasma acylated ghrelin levels before and after a meal were determined in the study participants using a commercial human acylated enzyme immunoassay kit; electrogastrograms were performed for 50 min before and after a standardized 10-min meal containing 265 kcal.RESULTS:There were no significant differences in plasma acylated ghrelin levels between healthy volunteers and patients with functional dyspepsia.However,in patients with functional dyspepsia,there was a negative correlation between fasting plasma acylated ghrelin levels and the sum score of epigastric pain (r =-0.427,P =0.047) and a positive correlation between the postprandial/fasting plasma acylated ghrelin ratio and the sum score of early satiety (r =0.428,P =0.047).Additionally,there was a negative correlation between fasting acylated ghrelin plasma levels and fasting normogastria (%) (r =-0.522,P =0.013).Interestingly,two functional dyspepsia patients showed paradoxically elevated plasma acylated ghrelin levels after the meal.CONCLUSION:Abnormal plasma acylated ghrelin levels before or after a meal may be related to several of the dyspeptic symptoms seen in patients with functional dyspepsia.

  3. Role of acylCoA binding protein in acylCoA transport, metabolism and cell signaling

    DEFF Research Database (Denmark)

    Knudsen, J; Jensen, M V; Hansen, J K

    1999-01-01

    Long chain acylCoA esters (LCAs) act both as substrates and intermediates in intermediary metabolism and as regulators in various intracellular functions. AcylCoA binding protein (ACBP) binds LCAs with high affinity and is believed to play an important role in intracellular acylCoA transport...... and pool formation and therefore also for the function of LCAs as metabolites and regulators of cellular functions [1]. The major factors controlling the free concentration of cytosol long chain acylCoA ester (LCA) include ACBP [2], sterol carrier protein 2 (SCP2) [3] and fatty acid binding protein (FABP...

  4. Acyl-acyl carrier protein as a source of fatty acids for bacterial bioluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Byers, D.M.; Meighen, E.A.

    1985-09-01

    Pulse-chase experiments with (/sup 3/H)tetradecanoic acid and ATP showed that the bioluminescence-related 32-kDa acyltransferase from Vibrio harveyi can specifically catalyze the deacylation of a /sup 3/H-labeled 18-kDa protein observed in extracts of this bacterium. The 18-kDa protein has been partially purified and its physical and chemical properties strongly indicate that it is fatty acyl-acyl carrier protein (acyl-ACP). Both this V. harveyi (/sup 3/H)acylprotein and (/sup 3/H)palmitoyl-ACP from Escherichia coli were substrates in vitro for either the V. harveyi 32-kDa acyltransferase or the analogous enzyme (34K) from Photobacterium phosphoreum. TLC analysis indicated that the hexane-soluble product of the reaction is fatty acid. No significant cleavage of either E. coli or V. harveyi tetradecanoyl-ACP was observed in extracts of these bacteria unless the 32-kDa or 34K acyltransferase was present. Since these enzymes are believed to be responsible for the supply of fatty acids for reduction to form the aldehyde substrate of luciferase, the above results suggest that long-chain acyl-ACP is the source of fatty acids for bioluminescence.

  5. Regulation of gastroduodenal motility: acyl ghrelin, des-acyl ghrelin and obestatin and hypothalamic peptides.

    Science.gov (United States)

    Fujimiya, Mineko; Ataka, Koji; Asakawa, Akihiro; Chen, Chih-Yen; Kato, Ikuo; Inui, Akio

    2012-01-01

    Real-time measurements for gut motility in conscious rats or mice combined with intracerebroventricular or intravenous injection of peptide agonists or antagonists allow us to understand the regulatory mechanism of gastrointestinal motility. Neuropeptide Y (NPY) in the arcuate nucleus in the hypothalamus stimulates the fasted motility in the duodenum, while urocortin in the paraventricular nucleus inhibits fed and fasted motility in the antrum and duodenum. Acyl ghrelin exerts stimulatory effects on the motility of the antrum and duodenum in both the fed and fasted state of animals. NPY Y2 and Y4 receptors in the brain may mediate the action of acyl ghrelin, and vagal afferent pathways might be involved in this mechanism. Des-acyl ghrelin exerts inhibitory effects on the motility of the antrum but not on the motility of the duodenum in the fasted state of animals. CRF type 2 receptor in the brain may mediate the action of des-acyl ghrelin, and vagal afferent pathways might not be involved in this mechanism. Obestatin exerts inhibitory effects on the motility of the antrum and duodenum in the fed state but not in the fasted state of animals. CRF type 1 and type 2 receptors in the brain may mediate the action of obestatin, and vagal afferent pathways might be partially involved in this mechanism.

  6. Characterization of a structurally and functionally diverged acyl-acyl carrier protein desaturase from milkweed seed.

    Science.gov (United States)

    Cahoon, E B; Coughlan, S J; Shanklin, J

    1997-04-01

    A cDNA for a structurally variant acyl-acyl carrier protein (ACP) desaturase was isolated from milkweed (Asclepias syriaca) seed, a tissue enriched in palmitoleic (16:1delta9)* and cis-vaccenic (18:1delta11) acids. Extracts of Escherichia coli that express the milkweed cDNA catalyzed delta9 desaturation of acyl-ACP substrates, and the recombinant enzyme exhibited seven- to ten-fold greater specificity for palmitoyl (16:0)-ACP and 30-fold greater specificity for myristoyl (14:0)-ACP than did known delta9-stearoyl (18:0)-ACP desaturases. Like other variant acyl-ACP desaturases reported to date, the milkweed enzyme contains fewer amino acids near its N-terminus compared to previously characterized delta9-18:0-ACP desaturases. Based on the activity of an N-terminal deletion mutant of a delta9-18:0-ACP desaturase, this structural feature likely does not account for differences in substrate specificities.

  7. Silver-catalyzed one-pot synthesis of arylnaphthalene lactones.

    Science.gov (United States)

    Eghbali, Nicolas; Eddy, Jennifer; Anastas, Paul T

    2008-09-05

    Arylnaphthalene lignan lactones are valuable natural products with promising anticancer and antiviral properties. In an effort to simplify their synthesis, we investigated a one-pot multicomponent coupling reaction between phenylacetylene, carbon dioxide, and 3-bromo-1-phenyl-1-propyne. After the corresponding 1,6-diyne was generated in situ, cyclization afforded the desired product. The level of regioselectivity was enhanced through the tuning of electronic properties. The use of cinnamyl bromide which led to the formation of a 1,6-enyne intermediate was also studied.

  8. Two new sesquiterpene lactones from Montanoa tomentosa ssp. microcephala.

    Science.gov (United States)

    Braca, A; Cioffi, G; Morelli, I; Venturella, F; Pizza, C; De Tommasi, N

    2001-11-01

    Two new sesquiterpene lactones: 8alpha-(4'-acetoxymethacryloyloxy)-3alpha,9beta-dihydroxy-1(10)E,4Z,11(13)-germacratrien-12,6alpha-olide (1) and 8alpha-(2'E)-(2'-acetoxymethyl-2'-butenoyloxy)-3alpha,9beta-dihydroxy-1(10)E,4Z,11(13)-germacratrien-12,6alphaolide (2), together with the known zoapatanolide A were isolated from the aerial parts of Montanoa tomentosa Cerv. in La Llave et Lex ssp. microcephala (Sch. Bip. In K. Koch) V.A. Funk (Asteraceae). The structures of all compounds were established on the basis of 1D, 2D NMR, and EIMS analysis.

  9. Sesquiterpene lactones from Ferula oopoda and their cytotoxic properties.

    Science.gov (United States)

    Kasaian, Jamal; Iranshahy, Milad; Masullo, Milena; Piacente, Sonia; Ebrahimi, Fatemeh; Iranshahi, Mehrdad

    2014-01-01

    Two new sesquiterpene lactones, namely feruhodin A and feruhodin B, together with six known compounds, daucoeudesmanolactone, dehydrooopodin, oopodin, badkhysin, 7-demethylplastochromenol, and scoparone, were isolated from the roots of Ferula oopoda. The structures of these compounds were elucidated by 1D and 2D NMR techniques as well as high-resolution mass spectrometry. Cytotoxic effects of these compounds were evaluated against two human cancer cell lines including MCF7and K562 using the Alamar blue assay. The results showed that dehydrooopodin possessed significant cytotoxic effects with IC₅₀ values of 15 and 5 μM against MCF7 and K562, respectively.

  10. Comparison of simultaneous patch testing with parthenolide and sesquiterpene lactone mix

    DEFF Research Database (Denmark)

    Orion, E; Paulsen, E; Andersen, Klaus Ejner

    1998-01-01

    Several studies have pointed out that the sesquiterpene lactone (SL) mix is a safe, though inadequate, screen for Compositae allergy. To test the usefulness of the sesquiterpene lactone parthenolide as a supplementary Compositae screening test to the mix, both were included in the standard series...

  11. [Isolation and identification of julibrotriterpennoidal lactone A from Albizia julibrissin Durazz].

    Science.gov (United States)

    Kang, S; Chen, S

    1992-06-01

    Julibrotriterpennoidal lactone A was isolated from the cortex of Albizia julibrissin. Its structure (the C28----C21 lactone of, 3 beta, 16 beta, 21 beta-trihydroxy-delta 12-oleanen-28-oic acid) has been determined on the basis of spectral evidence (IR, 1HNMR, 13C NMR and MS).

  12. Radical photocyclization route for macrocyclic lactone ring expansion and conversion to macrocyclic lactams and ketones.

    Science.gov (United States)

    Nishikawa, Keisuke; Yoshimi, Yasuharu; Maeda, Kousuke; Morita, Toshio; Takahashi, Ichiro; Itou, Tatsuya; Inagaki, Sho; Hatanaka, Minoru

    2013-01-18

    A new method for the synthesis of macrocyclic lactones, lactams, and ketones, which utilizes photoinduced intramolecular radical cyclization reactions of substrates containing tethered carboxylic acids and α,β-unsaturated carbonyl moieties, has been uncovered. Photocyclization of the carboxylic acids tethered acrylate ester, which were prepared starting from the macrocyclic lactones, gave the two-carbon elongated macrocyclic lactones via decarboxylation. Similar photoreactions of carboxylic acid tethered acryl amide or α,β-unsaturated ketone moieties, which were also prepared starting from the macrocyclic lactones, produced macrocyclic lactams or ketones, respectively. The simple approach can be readily applied to the preparation of a variety of macrocyclic lactones, lactams, and ketones with tunable ring sizes.

  13. Production d'arômes de type lactone par des levures

    Directory of Open Access Journals (Sweden)

    Alchihab, M.

    2010-01-01

    Full Text Available Production of aroma lactones by yeasts. Lactones are widely distributed in foods and beverages as aroma compounds. Their extraction from natural products is very expensive. Most of them can also be obtained in a chemical way, which is not well perceived by consumers. As an alternative, biotechnology proposes to use whole cells or enzymes to produce lactones by biotransformation or bioconversion of fatty acids. Different studies and patents have been conducted on that matter. In most cases, yeasts are the biological agent used. The main concerned lactones are γ- and δ-decalactones, γ-octalactone and γ-dodecalactone. This article describes lactones and their production by yeasts; particular attention will be devoted to the γ-decalactone.

  14. Selective acylation of primary amines in peptides and proteins

    NARCIS (Netherlands)

    Abello, N.; Kerstjens, H.A.M.; Postma, D.S; Bischoff, Rainer

    2007-01-01

    N-hydroxysuccinimide (NHS) esters are derivatizing agents that target primary amine groups. However, even a small molar excess of NHS may lead to acylation of hydroxyl-containing amino acids as a side reaction. We report a straightforward method for the selective removal of ester-linked acyl groups

  15. Understanding Acyl Chain and Glycerolipid Metabolism in Plants

    Energy Technology Data Exchange (ETDEWEB)

    Ohlrogge, John B.

    2013-11-05

    Progress is reported in these areas: acyl-editing in initial eukaryotic lipid assembly in soybean seeds; identification and characterization of two Arabidopsis thaliana lysophosphatidyl acyltransferases with preference for lysophosphatidylethanolamine; and characterization and subcellular distribution of lysolipid acyl transferase activity of pea leaves.

  16. Characterization of the "Escherichia Coli" Acyl Carrier Protein Phosphodiesterase

    Science.gov (United States)

    Thomas, Jacob

    2009-01-01

    Acyl carrier protein (ACP) is a small essential protein that functions as a carrier of the acyl intermediates of fatty acid synthesis. ACP requires the posttranslational attachment of a 4'phosphopantetheine functional group, derived from CoA, in order to perform its metabolic function. A Mn[superscript 2+] dependent enzymatic activity that removes…

  17. Rapid Hydrogen Shift Reactions in Acyl Peroxy Radicals

    DEFF Research Database (Denmark)

    Knap, Hasse Christian; Jørgensen, Solvejg

    2017-01-01

    -shift reactions are much faster than the reactions with NO and HO2 under most atmospheric conditions and must be included in the atmospheric models when hydroperoxy acyl peroxy radicals are oxidized. Finally, we have observed that H-shift reactions in a pentane acyl peroxy radical (C5-AOO) is fast (>1 s–1...

  18. Enzymatic synthesis and NMR studies of acylated sucrose acetates

    NARCIS (Netherlands)

    Steverink-De Zoete, M.C.; Kneepkens, M.F.M.; Waard, de P.; Woudenberg-van Oosterom, M.; Gotlieb, K.F.; Slaghek, T.

    1999-01-01

    The lipase-catalyzed esterification of partially acetylated sucrose has been studied. It was shown that the chemical acetylation increased the reaction rate of the subsequent enzymatic acylation. Thus it was possible to perform the enzymatic acylation in the absence of solvents while underivatized s

  19. The thermodynamic properties of alkylated γ-lactones

    Science.gov (United States)

    Emel'Yanenko, V. N.; Verevkin, S. P.; Burakova, E. N.; Roganov, G. N.; Georgieva, M. K.

    2009-04-01

    The enthalpies of formation of γ-pentanolactone ( I), γ-hexanolactone ( II), and γ-nonanolactone ( III) were determined by combustion calorimetry. The enthalpies of vaporization of these lactones were measured by the transfer method. Conformational analysis was performed and equilibrium structures, sets of fundamental vibrations, moments of inertia, and total energies of the stablest conformers of I, II, and III were calculated by the B3LYP/6-311G( d, p), G3MP2, and CBS-QB3 methods. The experimental IR spectra and calculated vibrational frequencies were used to obtain sets of fundamental vibrations of the stablest conformations. The thermodynamic properties of I- III in the ideal gas state were determined over the temperature range 0-1500 K. Additive and quantum-chemical methods were applied to estimate the Δf H o(g) values of a number of γ-lactones. Composite quantum-chemical methods were used to obtain the energies of monomethyl γ-butyrolactones and estimate their relative stability depending on the position of the methyl substituent in the ring.

  20. Hologram QSAR Studies of Antiprotozoal Activities of Sesquiterpene Lactones

    Directory of Open Access Journals (Sweden)

    Gustavo H. G. Trossini

    2014-07-01

    Full Text Available Infectious diseases such as trypanosomiasis and leishmaniasis are considered neglected tropical diseases due the lack for many years of research and development into new drug treatments besides the high incidence of mortality and the lack of current safe and effective drug therapies. Natural products such as sesquiterpene lactones have shown activity against T. brucei and L. donovani, the parasites responsible for these neglected diseases. To evaluate structure activity relationships, HQSAR models were constructed to relate a series of 40 sesquiterpene lactones (STLs with activity against T. brucei, T. cruzi, L. donovani and P. falciparum and also with their cytotoxicity. All constructed models showed good internal (leave-one-out q2 values ranging from 0.637 to 0.775 and external validation coefficients (r2test values ranging from 0.653 to 0.944. From HQSAR contribution maps, several differences between the most and least potent compounds were found. The fragment contribution of PLS-generated models confirmed the results of previous QSAR studies that the presence of α,β-unsatured carbonyl groups is fundamental to biological activity. QSAR models for the activity of these compounds against T. cruzi, L. donovani and P. falciparum are reported here for the first time. The constructed HQSAR models are suitable to predict the activity of untested STLs.

  1. Hologram QSAR studies of antiprotozoal activities of sesquiterpene lactones.

    Science.gov (United States)

    Trossini, Gustavo H G; Maltarollo, Vinícius G; Schmidt, Thomas J

    2014-07-18

    Infectious diseases such as trypanosomiasis and leishmaniasis are considered neglected tropical diseases due the lack for many years of research and development into new drug treatments besides the high incidence of mortality and the lack of current safe and effective drug therapies. Natural products such as sesquiterpene lactones have shown activity against T. brucei and L. donovani, the parasites responsible for these neglected diseases. To evaluate structure activity relationships, HQSAR models were constructed to relate a series of 40 sesquiterpene lactones (STLs) with activity against T. brucei, T. cruzi, L. donovani and P. falciparum and also with their cytotoxicity. All constructed models showed good internal (leave-one-out q2 values ranging from 0.637 to 0.775) and external validation coefficients (r2test values ranging from 0.653 to 0.944). From HQSAR contribution maps, several differences between the most and least potent compounds were found. The fragment contribution of PLS-generated models confirmed the results of previous QSAR studies that the presence of α,β-unsatured carbonyl groups is fundamental to biological activity. QSAR models for the activity of these compounds against T. cruzi, L. donovani and P. falciparum are reported here for the first time. The constructed HQSAR models are suitable to predict the activity of untested STLs.

  2. Spectrophotometric determination of total lactones in Andrographis paniculata Nees

    Directory of Open Access Journals (Sweden)

    Napaporn Jantakun

    2005-11-01

    Full Text Available A spectrophotometric method for determination of total lactones in Andrographis paniculata was established by using dinitrobenzoic acid and potassium hydroxide solutions as colour forming agents. The absorbance of the solution was determined at 536 nm. The linearity range was 12-72 × 10-6 g.ml-1. The detection limit was 1.2 μg, the quantitation limit was 4.23 μg. The intraday variation had an average of slope 6082.97 g.ml-1, % RSD 0.10; an average intercept 0.2786, %RSD 3.66 (n=3. The interday variation had an average of 6146 g.ml-1 with the %RSD of 6.30 and an average intercept 0.2628, %RSD 4.95 (n=4. The coefficients of determination were 0.998-0.999. The total lactones content, calculated as andrographolide, determined by this method was 8.61±0.52% (n=4 and by the official method, Thai Herbal Pharmacopoeia, was 8.12±0.34% (n=2. The results of the two methods do not differ significantly at P=0.05 (P(|t|>0.903 = 0.53

  3. Erbium trifluoromethanesulfonate-catalyzed Friedel–Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Hansen, Poul Erik; Nguyen, Hai Truong;

    2015-01-01

    Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel–Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation...

  4. Metabolism of ricinoleic acid into gamma-decalactone: beta-oxidation and long chain acyl intermediates of ricinoleic acid in the genus Sporidiobolus sp.

    Science.gov (United States)

    Blin-Perrin, C; Molle, D; Dufosse, L; Le-Quere, J L; Viel, C; Mauvais, G; Feron, G

    2000-07-01

    In order to study differences in gamma-decalactone production in yeast, four species of Sporidiobolus were cultivated with 5% of methyl ricinoleate as the lactone substrate. In vivo studies showed different time courses of intermediates of ricinoleic acid breakdown between the four species. In vitro studies of the beta-oxidation system were conducted with crude cell extracts of Sporidiobolus spp. and with ricinoleyl-CoA (RCoA) as substrate. The beta-oxidation was detected by measuring acyl-CoA oxidase, 3-hydroxyacyl-CoA dehydrogenase activities, and acetyl-CoA production. The time courses of the CoA esters resulting from RCoA breakdown by crude extract of Sporidiobolus spp. permit the proposal of different metabolic models in the yeast. These models explained the differences observed during in vivo studies.

  5. Selectivity and Efficiency of Conductive Molecularly Imprinted Polymer (c-MIP Based on 5-Phenyl-Dipyrromethane and 5-Phenol-Dipyrromethane for Quorum Sensing Precursors Detection

    Directory of Open Access Journals (Sweden)

    Sabina Susmel

    2017-02-01

    Full Text Available Functional polymers that selectively recognize target compounds are developed by imprinting polymerization. In the present paper, two different dipyrromethanes, 5-phenol-dipyrromethane (5-pOH-DP and 5-phenyl-dipyrromethane (5-ph-DP, are synthetized and investigated to develop conductive molecularly imprinted polymer (cMIP sensors. As target molecules, two homoserine lactone derivatives were templated by an electrochemically driven polymerization process. Acyl-homoserine lactones (AHLs, also called homoserine lactones (HS, are a class of signaling molecules involved in bacterial quorum sensing (QS, which is a strategy of coordination among bacteria mediated by population density. The preparation of cMIP from 5-pOH-DP and 5-ph-DP in the presence of acetyl-homoserine lactone (Acetyl-HS or carboxybenzyl-homoserine lactone (Cbz-HS was performed by cyclic voltammetry (CV. The cMIP selectivity and sensitivity were assessed by microgravimetry (QCM. Both series of measurements were performed with the aid of an Electrochemical Quartz Crystal Microbalance (EQCM/QCM. The experimental evidences are discussed with respect to NMR measurements that were conducted to gain insight into the interactions established between monomers and templates. The NMR data interpretation offers preliminary information about the most probable positions involved in interaction development for both molecules and highlights the role of the hydration shell. The QCM-cMIP sensor was able to detect the analyte in the linear range from 10−8 mol·L−1 to 10−6 mol·L−1 and a limit of detection (LOD of 22.3 ng (3σ of the blank signal were evaluated. QCM rebinding tests demonstrated that cMIP selectivity was driven by the pendant group of dipyrromethane, which was also confirmed by the NMR data.

  6. Exploring the Molecular Basis for Selective Binding of Homoserine Dehydrogenase from Mycobacterium leprae TN toward Inhibitors: A Virtual Screening Study

    Science.gov (United States)

    Zhan, Dongling; Wang, Dongmei; Min, Weihong; Han, Weiwei

    2014-01-01

    Homoserine dehydrogenase (HSD) from Mycobacterium leprae TN is an antifungal target for antifungal properties including efficacy against the human pathogen. The 3D structure of HSD has been firmly established by homology modeling methods. Using the template, homoserine dehydrogenase from Thiobacillus denitrificans (PDB Id 3MTJ), a sequence identity of 40% was found and molecular dynamics simulation was used to optimize a reliable structure. The substrate and co-factor-binding regions in HSD were identified. In order to determine the important residues of the substrate (l-aspartate semialdehyde (l-ASA)) binding, the ASA was docked to the protein; Thr163, Asp198, and Glu192 may be important because they form a hydrogen bond with HSD through AutoDock 4.2 software. After use of a virtual screening technique of HSD, the four top-scoring docking hits all seemed to cation–π ion pair with the key recognition residue Lys107, and Lys207. These ligands therefore seemed to be new chemotypes for HSD. Our results may be helpful for further experimental investigations. PMID:24469317

  7. Exploring the Molecular Basis for Selective Binding of Homoserine Dehydrogenase from Mycobacterium leprae TN toward Inhibitors: A Virtual Screening Study

    Directory of Open Access Journals (Sweden)

    Dongling Zhan

    2014-01-01

    Full Text Available Homoserine dehydrogenase (HSD from Mycobacterium leprae TN is an antifungal target for antifungal properties including efficacy against the human pathogen. The 3D structure of HSD has been firmly established by homology modeling methods. Using the template, homoserine dehydrogenase from Thiobacillus denitrificans (PDB Id 3MTJ, a sequence identity of 40% was found and molecular dynamics simulation was used to optimize a reliable structure. The substrate and co-factor-binding regions in HSD were identified. In order to determine the important residues of the substrate (l-aspartate semialdehyde (l-ASA binding, the ASA was docked to the protein; Thr163, Asp198, and Glu192 may be important because they form a hydrogen bond with HSD through AutoDock 4.2 software. neuraminidaseAfter use of a virtual screening technique of HSD, the four top-scoring docking hits all seemed to cation–π ion pair with the key recognition residue Lys107, and Lys207. These ligands therefore seemed to be new chemotypes for HSD. Our results may be helpful for further experimental investigations.

  8. Exploring the molecular basis for selective binding of homoserine dehydrogenase from Mycobacterium leprae TN toward inhibitors: a virtual screening study.

    Science.gov (United States)

    Zhan, Dongling; Wang, Dongmei; Min, Weihong; Han, Weiwei

    2014-01-24

    Homoserine dehydrogenase (HSD) from Mycobacterium leprae TN is an antifungal target for antifungal properties including efficacy against the human pathogen. The 3D structure of HSD has been firmly established by homology modeling methods. Using the template, homoserine dehydrogenase from Thiobacillus denitrificans (PDB Id 3MTJ), a sequence identity of 40% was found and molecular dynamics simulation was used to optimize a reliable structure. The substrate and co-factor-binding regions in HSD were identified. In order to determine the important residues of the substrate (L-aspartate semialdehyde (L-ASA)) binding, the ASA was docked to the protein; Thr163, Asp198, and Glu192 may be important because they form a hydrogen bond with HSD through AutoDock 4.2 software. neuraminidaseAfter use of a virtual screening technique of HSD, the four top-scoring docking hits all seemed to cation-π ion pair with the key recognition residue Lys107, and Lys207. These ligands therefore seemed to be new chemotypes for HSD. Our results may be helpful for further experimental investigations.

  9. Synthesis of -aryl--lactones and relationship: Structure – antifeedant and antifungal activity

    Indian Academy of Sciences (India)

    Andrzej Skrobiszewski; Witold Gładkowski; Paulina Walczak; Anna Gliszczyńska; Gabriela Maciejewska; Tomasz Klejdysz; Jan Nawrot; Czesław Wawrzeńczyk

    2015-04-01

    Eighteen racemic -aryl--lactones derived from simple aromatic aldehydes have been obtained in the chemical synthesis. Iodolactones (5c and 6c) were synthesized from ()-4-(benzo[][1′,3′]-dioxol-5′-yl)- but-3-en-2-one (1). Reductive dehalogenation of iodolactones 5a–c and 6a–c afforded -ethyl--lactones (7a–c, 8a–c) whereas the unsaturated lactones (9a–c, 10a–c) were obtained by dehydrohalogenation of iodolactones. All synthesized lactones were fully characterized by spectroscopic data (NMR, IR, HRMS) and subjected to the tests on the antifeedant activity towards Tribolium confusum, Trogoderma granarium and Sitophilus granaries as well to the tests on the antifungal activity towards four Fusarium species. The biological tests allowed to find some relationships between the structure and biological activity of the compounds studied. -Ethyl--lactones 7a–c, 8a–c and unsaturated lactones 9a–c, 10a-c were usually stronger antifeedants than their parent iodolactones 5a–c and 6a–c. trans-Iodolactones 6a–c were more active than cis isomers 5a-c both in antifeedant and antifungal assays. The structure of aromatic substituent was the key factor in antifungal activity. The lactones with benzo [][1,3]dioxole ring (5c, 6c, 7c, 8c, 9c) were the most active whereas those with unsubstituted benzene ring exhibited almost no activity.

  10. Regulation of very-long acyl chain ceramide synthesis by acyl-CoA-binding protein

    DEFF Research Database (Denmark)

    Ferreira, Natalia Santos; Engelsby, Hanne; Neess, Ditte

    2017-01-01

    -long-chain acyl-CoA esters, which is required for its ability to stimulate CerS activity. We also show that high-speed liver cytosol from wild-type mice activates CerS3 activity, whereas cytosol from ACBP knock-out mice does not. Consistently, CerS2 and CerS3 activities are significantly reduced in the testes...

  11. Towards the industrialization of new biosurfactants: Biotechnological opportunities for the lactone esterase gene from Starmerella bombicola.

    Science.gov (United States)

    Roelants, Sophie L K W; Ciesielska, Katarzyna; De Maeseneire, Sofie L; Moens, Helena; Everaert, Bernd; Verweire, Stijn; Denon, Quenten; Vanlerberghe, Brecht; Van Bogaert, Inge N A; Van der Meeren, Paul; Devreese, Bart; Soetaert, Wim

    2016-03-01

    Although sophorolipids (SLs) produced by S. bombicola are a real showcase for the industrialization of microbial biosurfactants, some important drawbacks are associated with this efficient biological process, e.g., the simultaneous production of acidic and lactonic SLs. Depending on the application, there is a requirement for the naturally produced mixture to be manipulated to give defined ratios of the components. Recently, the enzyme responsible for the lactonization of SLs was discovered. The discovery of the gene encoding this lactone esterase (sble) enabled the development of promising S. bombicola strains producing either solely lactonic (using a sble overexpression strain described in this paper: oe sble) or solely acidic SLs (using a sble deletion strain, which was recently described, but not characterized yet: Δsble). The new S. bombicola strains were used to investigate the production processes (fermentation and purification) of either lactonic or acidic SLs. The strains maintain the high inherent productivities of the wild-type or even perform slightly better and thus represent a realistic industrial opportunity. 100% acidic SLs with a mixed acetylation pattern were obtained for the Δsble strain, while the inherent capacity to selectively produce lactonic SLs was significantly increased (+42%) for the oe sble strain (99% lactonic SLs). Moreover, the regulatory effect of citrate on lactone SL formation for the wild-type was absent in this new strain, which indicates that it is more robust and better suited for the industrial production of lactonic SLs. Basic parameters were determined for the purified SLs, which confirm that the two new strains produce molecules with distinctive properties of which the application potential can now easily be investigated independently.

  12. Acyl-acyl carrier protein thioesterase activity from sunflower (Helianthus annuus L.) seeds.

    Science.gov (United States)

    Martínez-Force, E; Cantisán, S; Serrano-Vega, M J; Garcés, R

    2000-10-01

    During sunflower (Helianthus annuus L.) seed formation there was an active period of lipid biosynthesis between 12 and 28 days after flowering (DAF). The maximum in-vitro acyl-acyl carrier protein (ACP) thioesterase activities (EC 3.1.2.14) were found at 15 DAF, preceding the largest accumulation of lipid in the seed. Data from the apparent kinetic parameters, Vmax and Km, from seeds of 15 and 30 DAF, showed that changes in acyl-ACP thioesterase activity are not only quantitative, but also qualitative, since, although the preferred substrate was always oleoyl-ACP, the affinity for palmitoyl-ACP decreased, whereas that for stearoyl-ACP increased with seed maturation. Bisubstrate assays carried out at 30 DAF seemed to indicate that the total activity found in mature seeds is due to a single enzyme with 100/75/15 affinity for oleoyl-ACP/stearoyl-ACP/ palmitoyl-ACP. In contrast, at 15 DAF, enzymatic data together with partial sequences from cDNAs indicated the presence of at least two enzymes with different properties, a FatA-like thioesterase, with a high affinity for oleoyl-ACP, plus a FatB-like enzyme, with preference for long-chain saturated fatty acids, both being expressed during the active lipid biosynthesis period. Competition assays carried out with CAS-5, a mutant with a higher content of palmitic acid in the seed oil, indicated that a modified FatA-type thioesterase is involved in the mutant phenotype.

  13. Grafting of chitosan with fatty acyl derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Chiandotti, Roberto S.; Rodrigues, Paula C.; Akcelrud, Leni, E-mail: leni@leniak.ne [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept de Quimica

    2010-07-01

    The internal plasticization of chitosan with covalently linked long aliphatic branches, typically 12C, was accomplished through the condensation of the amino groups of chitosan with acidic derivatives of lauric acid, as lauroyl anhydride or lauroyl chloride, that are more reactive than the fatty acid itself. The chemical pathway led to selective N-acylation. The degree of substitution was quantitatively determined by FTIR and {sup 1}H NMR and varied between 3 and 35%. The FTIR quantitative analysis was based in a calibration method with good accuracy. The modified chitosan products were soluble in neutral water and/or DMF according to the degree of substitution. The modified chitosan films were more flexible than the pristine, non-modified ones. (author)

  14. Palladium-Catalyzed Environmentally Benign Acylation.

    Science.gov (United States)

    Suchand, Basuli; Satyanarayana, Gedu

    2016-08-05

    Recent trends in research have gained an orientation toward developing efficient strategies using innocuous reagents. The earlier reported transition-metal-catalyzed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp(2) C-H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and commercially available iodo arenes and aldehydes, for the synthesis of a wide variety of ketones. Moreover, this method comprises direct coupling of iodoarenes with aldehydes without activation of the carbonyl and also without directing group assistance. Significantly, the strategy was successfully applied to the synthesis n-butylphthalide and pitofenone.

  15. Synthesis, characterization and antiproliferative activity of β-aryl-δ-iodo-γ-lactones

    Science.gov (United States)

    Wzorek, Alicja; Gawdzik, Barbara; Gładkowski, Witold; Urbaniak, Mariusz; Barańska, Anita; Malińska, Maura; Woźniak, Krzysztof; Kempińska, Katarzyna; Wietrzyk, Joanna

    2013-09-01

    A convenient pathway for the synthesis of new of β-aryl-δ-iodo-γ-lactones is described. The synthetic route led to both cis and trans isomers which were separated by column chromatography or crystallization. The structures of synthesized compounds were confirmed by spectroscopic methods: IR, NMR and HR-MS. For lactones with naphthyl ring (6e and 7e) the crystal structures were also obtained. The lactones were screened for biological evaluation against cancer line HL-60 (human promyelocytic leukemia). The tests showed that the presence of substituent at the benzene ring does not significantly affect the antiproliferative activity of the compound.

  16. Quorum sensing in gram-negative bacteria

    DEFF Research Database (Denmark)

    Wu, H.; Song, Z.J.; Høiby, N.

    2004-01-01

    Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

  17. Five new lactone derivatives from the stems of Dendrobium nobile.

    Science.gov (United States)

    Zhou, Xue-Ming; Zheng, Cai-Juan; Wu, Jia-Ting; Chen, Guang-Ying; Chen, Jun; Sun, Chong-Ge

    2016-12-01

    Five new lactone derivatives decumbic acids A and B (1 and 2), (-)-decumbic acid (3a), (-)- and (+)-dendrolactone (4a and 4b) together with four known compounds (3b and 5-7) were isolated from the stems of Dendrobium nobile. Their structures were elucidated using comprehensive spectroscopic methods. Compounds 3a and 3b, 4a and 4b were isolated as two pair of enantiomers by chiral HPLC. The absolute configurations of 1, 2, 3a, 4a and 4b were determined by optical rotation and X-ray crystallographic analysis. The inhibitory activities of all compounds against nine phytopathogenic fungi and three cancer cell lines were evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. How do the macrocyclic lactones kill filarial nematode larvae?

    Science.gov (United States)

    Wolstenholme, Adrian J; Maclean, Mary J; Coates, Ruby; McCoy, Ciaran J; Reaves, Barbara J

    2016-09-01

    The macrocyclic lactones (MLs) are one of the few classes of drug used in the control of the human filarial infections, onchocerciasis and lymphatic filariasis, and the only one used to prevent heartworm disease in dogs and cats. Despite their importance in preventing filarial diseases, the way in which the MLs work against these parasites is unclear. In vitro measurements of nematode motility have revealed a large discrepancy between the maximum plasma concentrations achieved after drug administration and the amounts required to paralyze worms. Recent evidence has shed new light on the likely functions of the ML target, glutamate-gated chloride channels, in filarial nematodes and supports the hypothesis that the rapid clearance of microfilariae that follows treatment involves the host immune system.

  19. Thermodynamics of ligand binding to acyl-coenzyme A binding protein studied by titration calorimetry

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; Sigurskjold, B W; Kragelund, B B

    1996-01-01

    Ligand binding to recombinant bovine acyl-CoA binding protein (ACBP) was examined using isothermal microcalorimetry. Microcalorimetric measurements confirm that the binding affinity of acyl-CoA esters for ACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-...

  20. Synthesis of coenzyme A thioesters using methyl acyl phosphates in an aqueous medium.

    Science.gov (United States)

    Pal, Mohan; Bearne, Stephen L

    2014-12-28

    Regioselective S-acylation of coenzyme A (CoA) is achieved under aqueous conditions using various aliphatic and aromatic carboxylic acids activated as their methyl acyl phosphate monoesters. Unlike many hydrophobic activating groups, the anionic methyl acyl phosphate mixed anhydride is more compatible with aqueous solvents, making it useful for conducting acylation reactions in an aqueous medium.

  1. Sesquiterpene lactones derived from Saussurea lappa induce apoptosis and inhibit invasion and migration in neuroblastoma cells

    Directory of Open Access Journals (Sweden)

    Keiichi Tabata

    2015-04-01

    Full Text Available Neuroblastoma is among the most fatal of solid tumors in the pediatric age group, even when treated aggressively. Therefore, a new effective therapeutic drug(s for neuroblastoma is urgently needed. To clarify the anticancer effects of the sesquiterpene lactones dehydrocostus lactone and costunolide, derived from Saussurea lappa, we examined the cytotoxic and migration/invasion-inhibitory effects of these compounds against neuroblastoma cell lines. Both the compounds exerted significant cytotoxicity against the neuroblastoma cell lines IMR-32, NB-39, SK-N-SH, and LA-N-1. Evidence of cellular apoptosis, such as nuclear condensation and membrane inversion, were observed after treatment with these compounds. Both compounds induced caspase-7 activation and PARP cleavage as confirmed by Western blotting. Furthermore, the sesquiterpene lactones also suppressed invasion and migration of the neuroblastoma cells. These results suggest that dehydrocostus lactone and costunolide are promising candidates for being developed into novel anticancer drugs effective against neuroblastoma.

  2. A Novel Triterpenoid Lactone, Schiprolactone A, from Schisandra propinqua (Wall.) Hook. f. et Thoms

    Institute of Scientific and Technical Information of China (English)

    陈业高; 秦国伟; 谢毓元

    2001-01-01

    Schiprolactone A, a triterpenoid lactone with a new side chanin skeleton was isolated from the stems of Schisandra propinqua together with schisanlactones A and B. Their structures were elucidated by spectral studies.

  3. Heartworms, macrocyclic lactones, and the specter of resistance to prevention in the United States

    National Research Council Canada - National Science Library

    Bowman, Dwight D

    2012-01-01

    In order to provide a background to current concerns relative to the possible resistance of heartworms to macrocyclic lactones, this review summarizes various studies in which lack of efficacies (LOEs...

  4. A convenient method for lactonization of α-allyl esters using iodine ...

    African Journals Online (AJOL)

    A convenient method for lactonization of α-allyl esters using iodine in dimethyl- sulphoxide. ... KEY WORDS: γ-Butyrolactones, α-Allyl esters, Iodine, Dimethyl sulphoxide. Bull. Chem. Soc. Ethiop. 2014, 28(3) ... Article Metrics. Metrics Loading .

  5. Two new acyclic diterpene-y-lactones from the leaves of Salix matsudana

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two new acyclic diterpene-(-lactones named hanliuine III (1) and hanliuine IV (2) were isolated from leaves of Salix matsudana (Chinese name "hanliu"). Their structures were deduced from spectral data.

  6. Acylated cyanidin 3-sambubioside-5-glucosides in Matthiola incana.

    Science.gov (United States)

    Saito, N; Tatsuzawa, F; Nishiyama, A; Yokoi, M; Shigihara, A; Honda, T

    1995-03-01

    Four acylated cyanidin 3-sambubioside-5-glucosides were isolated from purple-violet flowers of Matthiola incana and their structures were determined by chemical and spectroscopic methods. Three acylated anthocyanins were cyanidin 3-O-(6-O-acyl-2-O-(2-O-sinapyl-beta-D-xylopyranosyl)-beta-D- glucopyranosides)-5-O-(6-O-malonyl-beta-D-glucopyranosides), in which the acyl group is p-coumaryl, caffeyl or ferulyl, respectively. The remaining pigment is free from malonic acid and was identified as cyanidin 3-O-(6-O-trans-ferulyl-2-O-(2- O-trans-sinapyl-beta-D-xylopyranosyl)-beta-D-glucopyranoside)-5-O- (beta-D-glucopyranoside). Analysis of the anthocyanin constituents in 16 purple-violet cultivars revealed that they contained the above triacylated anthocyanins in variable amounts as main pigments. An aromatic pair of pigments containing sinapic and ferulic acids are considered to produce an important intramolecular effect, making bluish colours in these flowers.

  7. A New Acylated Flavonoid from Anaphalis aureo-punctata

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new acylated tlavonoid glycoside, 3-O-kaempferol-3-O-acetyl-6-O-(P-coumaroyl)-β-D-glucopyranoside 1 was isolated from the whole plant of Anaphalis aureo-punctata. The structure was established by spectral methods.

  8. Evolution of the acyl-CoA binding protein (ACBP)

    DEFF Research Database (Denmark)

    Burton, Mark; Rose, Timothy M; Faergeman, Nils J

    2005-01-01

    Acyl-CoA-binding protein (ACBP) is a 10 kDa protein that binds C12-C22 acyl-CoA esters with high affinity. In vitro and in vivo experiments suggest that it is involved in multiple cellular tasks including modulation of fatty acid biosynthesis, enzyme regulation, regulation of the intracellular acyl......-CoA pool size, donation of acyl-CoA esters for beta-oxidation, vesicular trafficking, complex lipid synthesis and gene regulation. In the present study, we delineate the evolutionary history of ACBP to get a complete picture of its evolution and distribution among species. ACBP homologues were identified...... in all four eukaryotic kingdoms, Animalia, Plantae, Fungi and Protista, and eleven eubacterial species. ACBP homologues were not detected in any other known bacterial species, or in archaea. Nearly all of the ACBP-containing bacteria are pathogenic to plants or animals, suggesting that an ACBP gene could...

  9. 3-Epiabruslactone A, a New Triterpene Lactone Isolated from Austroplenckia populnea

    Directory of Open Access Journals (Sweden)

    Silva Grácia Divina de Fátima

    1998-01-01

    Full Text Available A new lactonic triterpene isolated from the heartwood of Austroplenckia populnea (Celastraceae was characterized as 3alpha-hydroxyolean-12-en-29,22alpha-olide (the gamma-lactone of the 3alpha,22alpha-dihydroxyolean-12-en-29alpha-oic acid, the 3-epimer of the abruslactone A, on the basis of its spectral data, chemical transformations, and single crystal X-ray analysis.

  10. Cooperative Al(Salen-Pyridinium Catalysts for the Asymmetric Synthesis of trans-Configured β-Lactones by [2+2]-Cyclocondensation of Acylbromides and Aldehydes: Investigation of Pyridinium Substituent Effects

    Directory of Open Access Journals (Sweden)

    René Peters

    2012-06-01

    Full Text Available The trans-selective catalytic asymmetric formation of β-lactones constitutes an attractive surrogate for anti-aldol additions. Recently, we have reported the first catalyst which is capable of forming trans-β-lactones with high enantioselectivity from aliphatic (and aromatic aldehyde substrates by cyclocondensation with acyl bromides. In that previous study the concepts of Lewis acid and organic aprotic ion pair catalysis were combined in a salen-type catalyst molecule. Since a pyridinium residue on the salen periphery is essential for high trans- and enantioselectivity, we were interested in the question of whether substituents on the pyridinium rings could be used to further improve the catalyst efficiency, as they might have a significant impact on the effective charges within the heterocycles. In the present study we have thus compared a small library of aluminum salen/bispyridinium catalysts mainly differing in the substituents on the pyridinium residues. As one result of these studies a new catalyst was identified which offers slightly superior stereoselectivity as compared to the previously reported best catalyst. NBO calculations have revealed that the higher stereoselectivity can arguably not be explained by the variation of the effective charge.

  11. Oxidative activation of dihydropyridine amides to reactive acyl donors

    DEFF Research Database (Denmark)

    Funder, Erik Daa; Trads, Julie Brender; Gothelf, Kurt Vesterager

    2015-01-01

    Amides of 1,4-dihydropyridine (DHP) are activated by oxidation for acyl transfer to amines, alcohols and thiols. In the reduced form the DHP amide is stable towards reaction with amines at room temperature. However, upon oxidation with DDQ the acyl donor is activated via a proposed pyridinium int...... intermediate. The activated intermediate reacts with various nucleophiles to give amides, esters, and thio-esters in moderate to high yields....

  12. Acyl-lupeol esters from Parahancornia amapa (Apocynaceae)

    OpenAIRE

    Carvalho,Mário G. de; Velloso,Carlos R. X.; Braz-Filho,Raimundo; Costa,William F. da

    2001-01-01

    From the roots of Parahancornia amapa, family Apocynaceae, the following compounds were isolated and identified nine new and ten known 3beta-O-acyl lupeol esters, beta-sitosterol, stigmasterol, beta-sitosterone, the triterpenoids beta-amyrin, alpha-amyrin, lupeol and their acetyl derivatives. The structures of these compounds were established by spectroscopic data, mainly ¹H and 13C (HBBD and DEPT) NMR spectra. The methyl esters obtained by hydrolysis of acyl lupeol esters and methylation of ...

  13. Germa-gamma-lactones as novel inhibitors of bacterial urease activity.

    Science.gov (United States)

    Amtul, Zareen; Follmer, Cristian; Mahboob, Sumera; Atta-Ur-Rahman; Mazhar, Muhammad; Khan, Khalid M; Siddiqui, Rafat A; Muhammad, Sajjad; Kazmi, Syed A; Choudhary, Mohammad Iqbal

    2007-05-04

    Organogermanium compounds have been used as pharmacological agents. However, very few reports are available on the synthesis and antibacterial activities of lactones containing organogermaniums. The purpose of the present investigation was to determine the effects of different lactone-substituted organogermaniums on bacterial growth and their urease activity. We report synthesis of 12 germa-gamma-lactones (GeL) and their antimicrobial activities against several bacterial pathogens. Antibacterial action of all GeL was highly selective against Gram-negative bacilli, particularly Proteus mirabilis, an important pathogen infecting the urinary tract. Furthermore, our data indicate that 8-quinoline derivatives were more potent against P. mirabilis than 2-methyl-8-quinoline. For example, the beta-(o-methylphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone and beta-(o-methoxyphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone were maximally active with MIC(90) of 61 and 94 microM, respectively. In vitro studies demonstrated a linear correlation between antibacterial activity and inhibition of P. mirabilis urease enzyme. Further kinetic analyses revealed that inhibition occurred in a noncompetitive and concentration-dependent manner with the minimum IC(50) of 31 microM for beta-(o-methoxyphenyl)-gamma,gamma-bis(8-quinolinoxy)germa-gamma-lactone. In conclusion, these findings suggest that GeL have potential to be developed as antimicrobial agents against P. mirabilis infection.

  14. The Role of Acyl-Glucose in Anthocyanin Modifications

    Directory of Open Access Journals (Sweden)

    Nobuhiro Sasaki

    2014-11-01

    Full Text Available Higher plants can produce a wide variety of anthocyanin molecules through modification of the six common anthocyanin aglycons that they present. Thus, hydrophilic anthocyanin molecules can be formed and stabilized by glycosylation and acylation. Two types of glycosyltransferase (GT and acyltransferase (AT have been identified, namely cytoplasmic GT and AT and vacuolar GT and AT. Cytoplasmic GT and AT utilize UDP-sugar and acyl-CoA as donor molecules, respectively, whereas both vacuolar GT and AT use acyl-glucoses as donor molecules. In carnation plants, vacuolar GT uses aromatic acyl-glucoses as the glucose donor in vivo; independently, vacuolar AT uses malylglucose, an aliphatic acyl-glucose, as the acyl-donor. In delphinium and Arabidopsis, p-hydroxybenzoylglucose and sinapoylglucose are used in vivo as bi-functional donor molecules by vacuolar GT and AT, respectively. The evolution of these enzymes has allowed delphinium and Arabidopsis to utilize unique donor molecules for production of highly modified anthocyanins.

  15. Acyl-CoA-binding protein (ACBP) can mediate intermembrane acyl-CoA transport and donate acyl-CoA for beta-oxidation and glycerolipid synthesis

    DEFF Research Database (Denmark)

    Rasmussen, J T; Færgeman, Nils J.; Kristiansen, K

    1994-01-01

    The dissociation constants for octanoyl-CoA, dodecanoyl-CoA and hexadecanoyl-CoA binding to acyl-CoA-binding protein (ACBP) were determined by using titration microcalorimetry. The KD values obtained, (0.24 +/- 0.02) x 10(-6) M, (0.65 +/- 0.2) x 10(-8) M and (0.45 +/- 0.2) x 10(-13) M respectively......, were much lower than expected. ACBP was able to extract hexadecanoyl-CoA from phosphatidylcholine membranes immobilized on a nitrocellulose membrane. The acyl-CoA/ACBP complex formed was able to transport acyl-CoA to mitochondria or microsomes in suspension, or to microsomes immobilized...

  16. Possible Role of Different Yeast and Plant Lysophospholipid:Acyl-CoA Acyltransferases (LPLATs) in Acyl Remodelling of Phospholipids.

    Science.gov (United States)

    Jasieniecka-Gazarkiewicz, Katarzyna; Demski, Kamil; Lager, Ida; Stymne, Sten; Banaś, Antoni

    2016-01-01

    Recent results have suggested that plant lysophosphatidylcholine:acyl-coenzyme A acyltransferases (LPCATs) can operate in reverse in vivo and thereby catalyse an acyl exchange between the acyl-coenzyme A (CoA) pool and the phosphatidylcholine. We have investigated the abilities of Arabidopsis AtLPCAT2, Arabidopsis lysophosphatidylethanolamine acyltransferase (LPEAT2), S. cerevisiae lysophospholipid acyltransferase (Ale1) and S. cerevisiae lysophosphatidic acid acyltransferase (SLC1) to acylate lysoPtdCho, lysoPtdEtn and lysoPtdOH and act reversibly on the products of the acylation; the PtdCho, PtdEtn and PtdOH. The tested LPLATs were expressed in an S. cervisiae ale1 strain and enzyme activities were assessed in assays using microsomal preparations of the different transformants. The results show that, despite high activity towards lysoPtdCho, lysoPtdEtn and lysoPtdOH by the ALE1, its capacities to operate reversibly on the products of the acylation were very low. Slc1 readily acylated lysoPtdOH, lysoPtdCho and lysoPtdEtn but showed no reversibility towards PtdCho, very little reversibility towards PtdEtn and very high reversibility towards PtdOH. LPEAT2 showed the highest levels of reversibility towards PtdCho and PtdEtn of all LPLATs tested but low ability to operate reversibly on PtdOH. AtLPCAT2 showed good reversible activity towards PtdCho and PtdEtn and very low reversibility towards PtdOH. Thus, it appears that some of the LPLATs have developed properties that, to a much higher degree than other LPLATs, promote the reverse reaction during the same assay conditions and with the same phospholipid. The results also show that the capacity of reversibility can be specific for a particular phospholipid, albeit the lysophospholipid derivatives of other phospholipids serve as good acyl acceptors for the forward reaction of the enzyme.

  17. Yeast acyl-CoA-binding protein: acyl-CoA-binding affinity and effect on intracellular acyl-CoA pool size

    DEFF Research Database (Denmark)

    Knudsen, J; Faergeman, N J; Skøtt, H;

    1994-01-01

    Acyl-CoA-binding protein (ACBP) is a 10 kDa protein characterized in vertebrates. We have isolated two ACBP homologues from the yeast Saccharomyces carlsbergensis, named yeast ACBP types 1 and 2. Both proteins contain 86 amino acid residues and are identical except for four conservative substitut...... resulted in a significant expansion of the intracellular acyl-CoA pool. Finally, Southern-blotting analysis of the two genes encoding ACBP types 1 and 2 in S. carlsbergensis strongly indicated that this species is a hybrid between S. cerevisiae and Saccharomyces monacensis....

  18. Structure-activity relationship study of sesquiterpene lactones and their semi-synthetic amino derivatives as potential antitrypanosomal products

    National Research Council Canada - National Science Library

    Zimmermann, Stefanie; Fouché, Gerda; De Mieri, Maria; Yoshimoto, Yukiko; Usuki, Toyonobu; Nthambeleni, Rudzani; Parkinson, Christopher J; van der Westhuyzen, Christiaan; Kaiser, Marcel; Hamburger, Matthias; Adams, Michael

    2014-01-01

    Sesquiterpene lactones (STLs) are natural products that have potent antitrypanosomal activity in vitro and, in the case of cynaropicrin, also reduce parasitemia in the murine model of trypanosomiasis...

  19. Lactonization and protonation of gluconic acid: a thermodynamicand kinetic study by potentiometry, nmr and esi-ms

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Gibson, P.; Clark, S.B.; Tian, G.; Zanonato, P.; Rao, L.

    2007-01-10

    In acidic aqueous solutions, gluconate protonation is coupled with lactonization of gluconic acid. With the decrease of pC{sub H}, two lactones ({delta}/{gamma}) are sequentially formed. The {delta}-lactone forms more readily than the {gamma}-lactone. In 0.1 M gluconate solutions, if pC{sub H} is above 2.5, only the {delta}-lactone is generated. When pC{sub H} is decreased below 2.0, the formation of the {gamma}-lactone is observable although the {delta}-lactone predominates. At I = 0.1 M NaClO{sub 4} and room temperature, the deprotonation constant of the carboxylic group, using the NMR technique, was determined to be log K{sub a} = 3.30 {+-} 0.02; the {delta}-lactonization constant, by the batch potentiometric titrations, was obtained to be log K{sub L} = - (0.54 {+-} 0.04). Using ESI-MS, the rate constants of the {delta}-lactonization and the hydrolysis at pC{sub H} {approx} 5.0 were estimated to be k{sub 1} = 3.2 x 10{sup -5} s{sup -1} and k{sup -1} = 1.1 x 10{sup -4} s{sup -1}, respectively.

  20. In Vitro Antiplasmodial Activity of Sesquiterpene Lactones from Ambrosia tenuifolia

    Directory of Open Access Journals (Sweden)

    V. Sülsen

    2011-01-01

    Full Text Available The in vitro antiplasmodial activity of Ambrosia tenuifolia organic extract and its isolated sesquiterpene lactones, psilostachyin and peruvin, has been evaluated against Plasmodium falciparum F32 and W2 strains. The cytotoxicity of both compounds was determined on lymphoid cells, and their corresponding selectivity indexes (SIs were calculated. Peruvin was the most active compound on F32 strain of P. falciparum with a 50% inhibitory concentration value (IC50 of 0.3 μg/mL (1.1 μM whereas psilostachyin showed activity on both strains (IC50 = 0.6 (2.1 μM and 1.8 μg/mL (6.4 μM. Fifty percent cytotoxic concentration (CC50 values (48 h were 6.8 μg/mL (24.3 μM and 10.0 μg/mL (37.9 μM for psilostachyin and peruvin, respectively.

  1. In Vitro Antiplasmodial Activity of Sesquiterpene Lactones from Ambrosia tenuifolia

    Science.gov (United States)

    Sülsen, V.; Gutierrez Yappu, D.; Laurella, L.; Anesini, C.; Gimenez Turba, A.; Martino, V.; Muschietti, L.

    2011-01-01

    The in vitro antiplasmodial activity of Ambrosia tenuifolia organic extract and its isolated sesquiterpene lactones, psilostachyin and peruvin, has been evaluated against Plasmodium falciparum F32 and W2 strains. The cytotoxicity of both compounds was determined on lymphoid cells, and their corresponding selectivity indexes (SIs) were calculated. Peruvin was the most active compound on F32 strain of P. falciparum with a 50% inhibitory concentration value (IC50) of 0.3 μg/mL (1.1 μM) whereas psilostachyin showed activity on both strains (IC50 = 0.6 (2.1 μM) and 1.8 μg/mL (6.4 μM)). Fifty percent cytotoxic concentration (CC50) values (48 h) were 6.8 μg/mL (24.3 μM) and 10.0 μg/mL (37.9 μM) for psilostachyin and peruvin, respectively. PMID:21716685

  2. Short communication: Macrocyclic lactone residues in butter from Brazilian markets.

    Science.gov (United States)

    Macedo, Fabio; Marsico, Eliane Teixeira; Conte-Júnior, Carlos Adam; de Almeida Furtado, Leonardo; Brasil, Taila Figueredo; Pereira Netto, Annibal Duarte

    2015-06-01

    Macrocyclic lactones (ML) are commonly used in drug formulations for the treatment of parasites in cattle. In Brazil, except for drugs (or formulations) with long-term (half-life) effects, ML are registered for use in bovines. Indiscriminate use of ML may result in the presence of residues in milk and dairy products due to their lipophilic properties and thermal stability. This study applied a method of liquid chromatography with fluorimetric detection, recently developed and validated for the determination of residues of abamectin, doramectin, ivermectin, and moxidectin in butter. The method was applied to 38 samples of commercial butter purchased in the metropolitan area of Rio de Janeiro, Brazil, between June and September 2013, analyzed in triplicate. Ivermectin was detected in 89.5% of the samples, with concentrations between 0.3 and 119.4 µg/kg; 76.3% of the samples contained doramectin (0.6 to 64.7 µg/kg) and 55.2% contained abamectin (0.7 to 4.5 µg/kg). Most butter samples (76.3%) contained residues of more than 1 ML; however, no residues of moxidectin were detected. The results showed a high incidence of the presence of avermectins in butter samples. Butter is not included in the Brazilian National Plan for Control of Residues and Contaminants in Animal Products. As ML residues concentrate in lipophilic compounds, butter and other fatty dairy products should be screened for the presence of ML residues.

  3. Dermatobia hominis: Potencial risk of resistance to macrocyclic lactones.

    Science.gov (United States)

    das Neves, José Henrique; Carvalho, Nadino; Amarante, Alessandro F T

    2015-09-15

    Dermatobia hominis is an ectoparasite that infests various species of mammals, including cattle, impairing the quality of cowhides and leather. After observing natural infestation with D. hominis larvae in cattle on two farms in the state of São Paulo, Brazil, we evaluated the efficacy of two macrocyclic lactones, ivermectin and moxidectin, against this parasite. The drugs were administered to 10 animals in each group, following the manufacturer's instructions. The groups were: Group 1-treated with ivermectin (0.2mg/kg of body weight (BW)); Group 2-treated with moxidectin (0.2mg/kg BW); and Group 3-control (untreated). On the farm in Pardinho, a total of 12 and 16 live larvae were found in 6 and in 8 animals 10 days after the treatment with ivermectin and moxidectin, respectively, while in the control group 4 bovines had a total of 7 live larvae. On the farm in Anhembi, 2, 4 and 6 live larvae were extracted from ivermectin, moxidectin and control groups, respectively, after the treatment. This is the first report of the presence of live D. hominis larvae after the treatment of cattle with ivermectin and moxidectin in Brazil. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Structure-Based Function Discovery of an Enzyme for the Hydrolysis of Phosphorylated Sugar Lactones

    Science.gov (United States)

    Xiang, Dao Feng; Kolb, Peter; Fedorov, Alexander A.; Xu, Chengfu; Fedorov, Elena V.; Narindoshivili, Tamari; Williams, Howard J.; Shoichet, Brian K.; Almo, Steven C.; Raushel, Frank M.

    2012-01-01

    Two enzymes of unknown function from the cog1735 subset of the amidohydrolase superfamily (AHS), LMOf2365_2620 (Lmo2620) from Listeria monocytogenes str. 4b F2365 and Bh0225 from Bacillus halodurans C-125, were cloned, expressed and purified to homogeneity. The catalytic functions of these two enzymes were interrogated by an integrated strategy encompassing bioinformatics, computational docking to three-dimensional crystal structures, and library screening. The three-dimensional structure of Lmo2620 was determined at a resolution of 1.6 Å with two phosphates and a binuclear zinc center in the active site. The proximal phosphate bridges the binuclear metal center and is 7.1 Å away from the distal phosphate. The distal phosphate hydrogen bonds with Lys-242, Lys-244, Arg-275 and Tyr-278. Enzymes within cog1735 of the AHS have previously been shown to catalyze the hydrolysis of substituted lactones. Computational docking of the high energy intermediate (HEI) form of the KEGG database to the three-dimensional structure of Lmo2620 highly enriched anionic lactones versus other candidate substrates. The active site structure and the computational docking results suggested that probable substrates would likely include phosphorylated sugar lactones. A small library of diacid sugar lactones and phosphorylated sugar lactones was synthesized and tested for substrate activity with Lmo2620 and Bh0225. Two substrates were identified for these enzymes, d-lyxono-1,4-lactone-5-phosphate and l-ribono-1,4-lactone-5-phosphate. The kcat/Km values for the cobalt-substituted enzymes with these substrates are ~105 M−1 s−1. PMID:22313111

  5. Sesquiterpene Lactones from Artemisia Genus: Biological Activities and Methods of Analysis

    Directory of Open Access Journals (Sweden)

    Bianca Ivanescu

    2015-01-01

    Full Text Available Sesquiterpene lactones are a large group of natural compounds, found primarily in plants of Asteraceae family, with over 5000 structures reported to date. Within this family, genus Artemisia is very well represented, having approximately 500 species characterized by the presence of eudesmanolides and guaianolides, especially highly oxygenated ones, and rarely of germacranolides. Sesquiterpene lactones exhibit a wide range of biological activities, such as antitumor, anti-inflammatory, analgesic, antiulcer, antibacterial, antifungal, antiviral, antiparasitic, and insect deterrent. Many of the biological activities are attributed to the α-methylene-γ-lactone group in their molecule which reacts through a Michael-addition with free sulfhydryl or amino groups in proteins and alkylates them. Due to the fact that most sesquiterpene lactones are thermolabile, less volatile compounds, they present no specific chromophores in the molecule and are sensitive to acidic and basic mediums, and their identification and quantification represent a difficult task for the analyst. Another problematic aspect is represented by the complexity of vegetal samples, which may contain compounds that can interfere with the analysis. Therefore, this paper proposes an overview of the methods used for the identification and quantification of sesquiterpene lactones found in Artemisia genus, as well as the optimal conditions for their extraction and separation.

  6. First identification of three p-menthane lactones and their potential precursor, menthofuran, in red wines.

    Science.gov (United States)

    Picard, Magali; de Revel, Gilles; Marchand, Stéphanie

    2017-02-15

    The p-menthane lactones constitute a family of powerful odorants, including the isomers of mintlactone and menthofurolactone that occur naturally in peppermint oil, known for their potent, mint-like olfactory properties. These lactones are closely related to the monoterpene-limonene secondary biotransformation and menthofuran has been identified as their common precursor in Mentha species. Using targeted GC-olfactometry and GC-MS analyses, together with quantification methods, we were able to demonstrate, for the first time, the presence of the diastereoisomers of these p-menthane lactones, as well as their common precursor, menthofuran, in red wines. In addition, we linked the presence of those lactones to interesting odorant zones, reminiscent of mint, detected in the studied wine. Although these p-menthane lactones may contribute individually to mint and coconut odors, sensory studies suggested for the first time that their combination at the levels found in the red wine studied resulted in a significant accentuation of freshness and mint notes.

  7. Ghrelin O-Acyl Transferase: Bridging Ghrelin and Energy Homeostasis

    Directory of Open Access Journals (Sweden)

    Andrew Shlimun

    2011-01-01

    Full Text Available Ghrelin O-acyl transferase (GOAT is a recently identified enzyme responsible for the unique n-acyl modification of ghrelin, a multifunctional metabolic hormone. GOAT structure and activity appears to be conserved from fish to man. Since the acyl modification is critical for most of the biological actions of ghrelin, especially metabolic functions, GOAT emerged as a very important molecule of interest. The research on GOAT is on the rise, and several important results reiterating its significance have been reported. Notable among these discoveries are the identification of GOAT tissue expression patterns, effects on insulin secretion, blood glucose levels, feeding, body weight, and metabolism. Several attempts have been made to design and test synthetic compounds that can modulate endogenous GOAT, which could turn beneficial in favorably regulating whole body energy homeostasis. This paper will focus to provide an update on recent advances in GOAT research and its broader implications in the regulation of energy balance.

  8. Caveolar fatty acids and acylation of caveolin-1.

    Directory of Open Access Journals (Sweden)

    Qian Cai

    Full Text Available PURPOSE: Caveolae are cholesterol and sphingolipids rich subcellular domains on plasma membrane. Caveolae contain a variety of signaling proteins which provide platforms for signaling transduction. In addition to enriched with cholesterol and sphingolipids, caveolae also contain a variety of fatty acids. It has been well-established that acylation of protein plays a pivotal role in subcellular location including targeting to caveolae. However, the fatty acid compositions of caveolae and the type of acylation of caveolar proteins remain largely unknown. In this study, we investigated the fatty acids in caveolae and caveolin-1 bound fatty acids. METHODS: Caveolae were isolated from Chinese hamster ovary (CHO cells. The caveolar fatty acids were extracted with Folch reagent, methyl esterificated with BF3, and analyzed by gas chromatograph-mass spectrometer (GC/MS. The caveolin-1 bound fatty acids were immunoprecipitated by anti-caveolin-1 IgG and analyzed with GC/MS. RESULTS: In contrast to the whole CHO cell lysate which contained a variety of fatty acids, caveolae mainly contained three types of fatty acids, 0.48 µg palmitic acid, 0.61 µg stearic acid and 0.83 µg oleic acid/caveolae preparation/5 × 10(7 cells. Unexpectedly, GC/MS analysis indicated that caveolin-1 was not acylated by myristic acid; instead, it was acylated by palmitic acid and stearic acid. CONCLUSION: Caveolae contained a special set of fatty acids, highly enriched with saturated fatty acids, and caveolin-1 was acylated by palmitic acid and stearic acid. The unique fatty acid compositions of caveolae and acylation of caveolin-1 may be important for caveolae formation and for maintaining the function of caveolae.

  9. Identification of unusual phospholipid fatty acyl compositions of Acanthamoeba castellanii.

    Science.gov (United States)

    Palusinska-Szysz, Marta; Kania, Magdalena; Turska-Szewczuk, Anna; Danikiewicz, Witold; Russa, Ryszard; Fuchs, Beate

    2014-01-01

    Acanthamoeba are opportunistic protozoan pathogens that may lead to sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba followed by aggressive treatment regimen. The plasma membrane of Acanthamoeba consists of 25% phospholipids (PL). The presence of C20 and, recently reported, 28- and 30-carbon fatty acyl residues is characteristic of amoeba PL. A detailed knowledge about this unusual PL composition could help to differentiate Acanthamoeba from other parasites, e.g. bacteria and develop more efficient treatment strategies. Therefore, the detailed PL composition of Acanthamoeba castellanii was investigated by 31P nuclear magnetic resonance spectroscopy, thin-layer chromatography, gas chromatography, high performance liquid chromatography and liquid chromatography-mass spectrometry. Normal and reversed phase liquid chromatography coupled with mass spectrometric detection was used for detailed characterization of the fatty acyl composition of each detected PL. The most abundant fatty acyl residues in each PL class were octadecanoyl (18∶0), octadecenoyl (18∶1 Δ9) and hexadecanoyl (16∶0). However, some selected PLs contained also very long fatty acyl chains: the presence of 28- and 30-carbon fatty acyl residues was confirmed in phosphatidylethanolamine (PE), phosphatidylserine, phosphatidic acid and cardiolipin. The majority of these fatty acyl residues were also identified in PE that resulted in the following composition: 28∶1/20∶2, 30∶2/18∶1, 28∶0/20∶2, 30∶2/20∶4 and 30∶3/20∶3. The PL of amoebae are significantly different in comparison to other cells: we describe here for the first time unusual, very long chain fatty acids with Δ5-unsaturation (30∶35,21,24) and 30∶221,24 localized exclusively in specific phospholipid classes of A. castellanii protozoa that could serve as specific biomarkers for the presence of these

  10. Identification of unusual phospholipid fatty acyl compositions of Acanthamoeba castellanii.

    Directory of Open Access Journals (Sweden)

    Marta Palusinska-Szysz

    Full Text Available Acanthamoeba are opportunistic protozoan pathogens that may lead to sight-threatening keratitis and fatal granulomatous encephalitis. The successful prognosis requires early diagnosis and differentiation of pathogenic Acanthamoeba followed by aggressive treatment regimen. The plasma membrane of Acanthamoeba consists of 25% phospholipids (PL. The presence of C20 and, recently reported, 28- and 30-carbon fatty acyl residues is characteristic of amoeba PL. A detailed knowledge about this unusual PL composition could help to differentiate Acanthamoeba from other parasites, e.g. bacteria and develop more efficient treatment strategies. Therefore, the detailed PL composition of Acanthamoeba castellanii was investigated by 31P nuclear magnetic resonance spectroscopy, thin-layer chromatography, gas chromatography, high performance liquid chromatography and liquid chromatography-mass spectrometry. Normal and reversed phase liquid chromatography coupled with mass spectrometric detection was used for detailed characterization of the fatty acyl composition of each detected PL. The most abundant fatty acyl residues in each PL class were octadecanoyl (18∶0, octadecenoyl (18∶1 Δ9 and hexadecanoyl (16∶0. However, some selected PLs contained also very long fatty acyl chains: the presence of 28- and 30-carbon fatty acyl residues was confirmed in phosphatidylethanolamine (PE, phosphatidylserine, phosphatidic acid and cardiolipin. The majority of these fatty acyl residues were also identified in PE that resulted in the following composition: 28∶1/20∶2, 30∶2/18∶1, 28∶0/20∶2, 30∶2/20∶4 and 30∶3/20∶3. The PL of amoebae are significantly different in comparison to other cells: we describe here for the first time unusual, very long chain fatty acids with Δ5-unsaturation (30∶35,21,24 and 30∶221,24 localized exclusively in specific phospholipid classes of A. castellanii protozoa that could serve as specific biomarkers for the presence of

  11. Acylation of Quercetin with a Novel Thermophilic Esterase as Biocatalyst

    Institute of Scientific and Technical Information of China (English)

    XIE Xiao-na; ZHANG Chun-li; XUN Er-na; WANG Jia-xin; ZHANG Hong; WANG Lei; WANG Zhi

    2012-01-01

    The regioselective acylation of quercetin catalyzed by a novel thermophilic esterase(APE1547)from the archaeon Aeropyrum pernix K1 was successfully conducted in organic solvents.The effects of acyl donor,substrate ratio,organic solvent,temperature,and water activity were investigated.Under the optimum conditions,a yield of 74% for its mono ester could be achieved in the reaction for about 6 h.With the reaction time extending to about 30 h,the final conversion of quercetin was about 100% and three products were synthesized.

  12. Total assignment of 1H and 13C NMR data for the sesquiterpene lactone 15-deoxygoyazensolide.

    Science.gov (United States)

    Heleno, Vladimir Constantino Gomes; Crotti, Antônio Eduardo Miller; Constantino, Mauricio Gomes; Lopes, Norberto Peporine; Lopes, João Luis Callegari

    2004-03-01

    We describe a complete analysis of the 1H and 13C spectra of the anti-inflamatory, schistossomicidal and trypanosomicidal sesquiterpene lactone 15-deoxygoyazensolide. This lactone, with a structure similar to other important ones, was studied by NMR techniques such as COSY, HMQC, HMBC, Jres and NOE experiments. The comparison of the data with some computational results led to an unequivocal assignment of all hydrogen and carbon chemical shifts, even eliminating some previous ambiguities. We were able to determine all hydrogen coupling constants (J) and signal multiplicities and to confirm the stereochemistry. A new method for the determination of the relative position of the lactonization and the position of the ester group on a medium-sized ring by NMR was developed.

  13. Quantitative analysis of sesquiterpene lactones in extract of Arnica montana L. by 1H NMR spectroscopy.

    Science.gov (United States)

    Staneva, Jordanka; Denkova, Pavletta; Todorova, Milka; Evstatieva, Ljuba

    2011-01-01

    (1)H NMR spectroscopy was used as a method for quantitative analysis of sesquiterpene lactones present in a crude lactone fraction isolated from Arnica montana. Eight main components - tigloyl-, methacryloyl-, isobutyryl- and 2-methylbutyryl-esters of helenalin (H) and 11α,13-dihydrohelenalin (DH) were identified in the studied sample. The method allows the determination of the total amount of sesquiterpene lactones and the quantity of both type helenalin and 11α,13-dihydrohelenalin esters separately. Furthermore, 6-O-tigloylhelenalin (HT, 1), 6-O-methacryloylhelenalin (HM, 2), 6-O-tigloyl-11α,13-dihydrohelenalin (DHT, 5), and 6-O-methacryloyl-11α,13-dihydrohelenalin (DHM, 6) were quantified as individual components.

  14. Genetic and biochemical characterization of a novel monoterpene epsilon-lactone hydrolase from Rhodococcus erythropolis DCL14

    NARCIS (Netherlands)

    Vlugt-Bergmans, van der C.J.B.; Werf, van der M.J.

    2001-01-01

    A monoterpene ε-lactone hydrolase (MLH) from Rhodococcus erythropolis DCL14, catalyzing the ring opening of lactones which are formed during degradation of several monocyclic monoterpenes, including carvone and menthol, was purified to apparent homogeneity. It is a monomeric enzyme of 31 kDa that is

  15. Neocosmospora sp.-derived resorcylic acid lactones with in vitro binding capacity for human opioid and cannabinoid receptors

    Science.gov (United States)

    Bioassay-guided fractionation of a fungus Neocosmospora sp. (UM-031509) resulted in the isolation of three new resorcyclic acid lactones, neocosmosin A (2), neocosmosin B (3) and neocosmosin C (4). Three known resorcylic acid lactones, monocillin IV (1), monocillin II (5) and monorden (6) were also ...

  16. Genetic and biochemical characterization of a novel monoterpene e-lactone hydrolase from Rhodococcus erythropolis DCL14

    NARCIS (Netherlands)

    Vlugt-Bergmans, C.J.B. van der; Werf, M.J. van der

    2001-01-01

    A monoterpene ε-lactone hydrolase (MLH) from Rhodococcus erythropolis DCL14, catalyzing the ring opening of lactones which are formed during degradation of several monocyclic monoterpenes, including carvone and menthol, was purified to apparent homogeneity. It is a monomeric enzyme of 31 kDa that is

  17. Quantification of several 4-alkyl substituted gamma-lactones in Australian wines.

    Science.gov (United States)

    Cooke, Rachel C; Capone, Dimitra L; van Leeuwen, Katryna A; Elsey, Gordon M; Sefton, Mark A

    2009-01-28

    Stable isotope dilution assays have been developed for gamma-octalactone (1), gamma-nonalactone (2), gamma-decalactone (3) and gamma-dodecalactone (4) in both white and red wines for the first time. (2)H(7)-analogues of each lactone were prepared for use as internal standards via a strategy employing ring-opening, esterification and oxidation of the respective starting lactones. The methods were shown to be highly accurate and reproducible (R(2) > or = 0.999; SD wines (n = 178) were analyzed for the presence of lactones 1-4. Fifty-eight white wines covering the varieties Chardonnay, Riesling, Sauvignon Blanc, Semillon and Viognier, as well as Botrytis style wines, were analyzed and showed broadly that gamma-octalactone (1) was the most common lactone, being observed above its limit of detection in 28 of the wines, followed by gamma-nonalactone (2) in 23 wines. The Botrytis style white wines had the highest concentrations of 1 and 2 (maximum concentrations 8.5 and 59 microg/L respectively). A total of 120 red wines covering the varieties Cabernet Sauvignon, Durif, Merlot, Pinot Noir and Shiraz were also studied and showed gamma-octalactone (1) and gamma-nonalactone (2) to be the most common lactones present, in 56 and 57 of the wines, respectively. gamma-Decalactone (3) was observed in only a small number (13) of red wine samples and not at all in the white varieties. gamma-Dodecalactone (4) was absent from all 178 samples studied. The highest concentrations of lactones 1, 2 and 3 in the red wines were 4.2, 39.7 and 4.0 microg/L respectively.

  18. Acyl-CoA Dehydrogenase 9 Is Required for the Biogenesis of Oxidative Phosphorylation Complex I

    NARCIS (Netherlands)

    J. Nouws; L. Nijtmans; S.M. Houten; M. Brand; M. Huynen; H. Venselaar; S. Hoefs; J. Gloerich; J. Kronick; T. Hutchin; P. Willems; R. Rodenburg; R. Wanders; L. van den Heuvel; J. Smeitink; R.O. Vogel

    2010-01-01

    Acyl-CoA dehydrogenase 9 (ACAD9) is a recently identified member of the acyl-CoA dehydrogenase family. It closely resembles very long-chain acyl-CoA dehydrogenase (VLCAD), involved in mitochondria! (3 oxidation of long-chain fatty acids. Contrary to its previously proposed involvement in fatty acid

  19. Influence of acylation on the adsorption of GLP-2 to hydrophobic surfaces

    DEFF Research Database (Denmark)

    Pinholt, Charlotte; Kapp, Sebastian J; Bukrinsky, Jens T

    2013-01-01

    Acylation of proteins with a fatty acid chain has proven useful for prolonging the plasma half-lives of proteins. In formulation of acylated protein drugs, knowledge about the effect of acylation with fatty acids on the adsorption behaviour of proteins at interfaces will be valuable. The aim of t...

  20. Influence of acylation on the adsorption of GLP-2 to hydrophobic surfaces

    NARCIS (Netherlands)

    Pinholt, C.; Kapp, S.J.; Bukrinsky, J.T.; Hostrup, S.; Frokjer, S.; Norde, W.; Jorgensen, L.

    2013-01-01

    Acylation of proteins with a fatty acid chain has proven useful for prolonging the plasma half-lives of proteins. In formulation of acylated protein drugs, knowledge about the effect of acylation with fatty acids on the adsorption behaviour of proteins at interfaces will be valuable. The aim of this

  1. The acylation of 1-acylglycero-3-phosphorylcholines by rat-liver microsomes

    NARCIS (Netherlands)

    Bosch, H. van den; Golde, L.M.G. van; Eibl, H.; Deenen, L.L.M. van

    1967-01-01

    1. 1. The transfer of acyl groups from acyl-coenzyme A derivatives to phosphatidylcholine by rat-liver microsomes was found to be significantly stimulated by the addition of synthetic 1-acylglycero-3-phosphorylcholines. Unsaturated acyl chains were transferred in preference to saturated ones, partic

  2. Acylation of salmon calcitonin modulates in vitro intestinal peptide flux through membrane permeability enhancement

    DEFF Research Database (Denmark)

    Trier, Sofie; Linderoth, Lars; Bjerregaard, Simon;

    2015-01-01

    hypothesize that tailoring the acylation may be used to optimize intestinal translocation. This work aims to characterize acylated analogues of the therapeutic peptide salmon calcitonin (sCT), which lowers blood calcium, by systematically increasing acyl chain length at two positions, in order to elucidate...

  3. [Effects of ginkgo diterpene lactones meglumine injection's activated carbon adsorption technology on officinal components].

    Science.gov (United States)

    Zhou, En-li; Wang, Ren-jie; Li, Miao; Wang, Wei; Xu, Dian-hong; Hu, Yang; Wang, Zhen-zhong; Bi, Yu-an; Xiao, Wei

    2015-10-01

    With the diversion rate of ginkgolide A, B, K as comprehensive evaluation indexes, the amount of activated carbon, ad- sorption time, mix rate, and adsorption temperature were selected as factors, orthogonal design which based on the evaluation method of information entropy was used to optimize activated carbon adsorption technology of ginkgo diterpene lactones meglumine injection. Opti- mized adsorption conditions were as follows: adsorbed 30 min with 0.2% activated carbon in 25 °C, 40 r ·min⁻¹, validation test re- sult display. The optimum extraction condition was stable and feasible, it will provide a basis for ginkgo diterpene lactone meglumine injection' activated carbon adsorption process.

  4. Aminocyclopentanols as sugar mimics. Synthesis from unsaturated bicyclic lactones by Overman rearrangement

    DEFF Research Database (Denmark)

    Bøjstrup, Marie; Fanefjord, Mette; Lundt, Inge

    2007-01-01

    Bicyclic cyclopentane lactones, prepared from bromodeoxyaldonolactones, were transformed into aminocyclopentanols with an Overman rearrangement as the key step. Two of the compounds prepared, 7 and 19, were found to be good inhibitors of jack bean alpha-mannosidase and beta-D-N-acetylglucosaminid......Bicyclic cyclopentane lactones, prepared from bromodeoxyaldonolactones, were transformed into aminocyclopentanols with an Overman rearrangement as the key step. Two of the compounds prepared, 7 and 19, were found to be good inhibitors of jack bean alpha-mannosidase and beta...

  5. Comparison of simultaneous patch testing with parthenolide and sesquiterpene lactone mix

    DEFF Research Database (Denmark)

    Orion, E; Paulsen, E; Andersen, Klaus Ejner

    1998-01-01

    Several studies have pointed out that the sesquiterpene lactone (SL) mix is a safe, though inadequate, screen for Compositae allergy. To test the usefulness of the sesquiterpene lactone parthenolide as a supplementary Compositae screening test to the mix, both were included in the standard series...... in 2 Danish dermatology departments. Among 2244 patients tested, 46 (2%) were positive to SL mix and 73-75% of these were positive to parthenolide. The results demonstrate that parthenolide is not suitable as a supplementary screening agent to SL mix, but may be a fairly good screen on its own...

  6. Sesquiterpene lactones. XXXII. Guaianolides in species from the genus Chartolepis Cass.

    Directory of Open Access Journals (Sweden)

    Gerard Nowak

    2014-01-01

    Full Text Available Differences in the composition of the "lactone fraction" of 4 species from the genus Chartolepis Cass. were observed. Cynaropierin was isolated from the above-ground parts of Chartolepis intermedia Boiss. and the occurrence there of grossheimin was confirmed. The following compounds were isolated from the above-ground parts of Chartolepis glastifolia (L. Cass.: centaurepensin, repin, cebellin C, acroptillin, cebellin D, cynaropicrin, cebellin F and janerin. Centaurepensin, repin, cebellin C, acroptillin, cynaropicrin, janerin and a new guaianolide, pterocaulin were isolated from the herb Chartolepis biebersteinii Jaub. et Spach. In addition to the lactones found in Chartolepis biebersteinii, Chartolepis pterocaula (Trautv. Czer. also accumulated grossheimin.

  7. Detection, Characterization, and Biological Effect of Quorum-Sensing Signaling Molecules in Peanut-Nodulating Bradyrhizobia

    Directory of Open Access Journals (Sweden)

    Walter Giordano

    2012-03-01

    Full Text Available Bacteria of the genus Bradyrhizobium are able to establish a symbiotic relationship with peanut (Arachis hypogaea root cells and to fix atmospheric nitrogen by converting it to nitrogenous compounds. Quorum sensing (QS is a cell-cell communication mechanism employed by a variety of bacterial species to coordinate behavior at a community level through regulation of gene expression. The QS process depends on bacterial production of various signaling molecules, among which the N-acylhomoserine lactones (AHLs are most commonly used by Gram-negative bacteria. Some previous reports have shown the production of QS signaling molecules by various rhizobia, but little is known regarding mechanisms of communication among peanut-nodulating strains. The aims of this study were to identify and characterize QS signals produced by peanut-nodulating bradyrhizobial strains and to evaluate their effects on processes related to cell interaction. Detection of AHLs in 53 rhizobial strains was performed using the biosensor strains Agrobacterium tumefaciens NTL4 (pZLR4 and Chromobacterium violaceum CV026 for AHLs with long and short acyl chains, respectively. None of the strains screened were found to produce AHLs with short acyl chains, but 14 strains produced AHLs with long acyl chains. These 14 AHL-producing strains were further studied by quantification of β-galactosidase activity levels (AHL-like inducer activity in NTL4 (pZLR4. Strains displaying moderate to high levels of AHL-like inducer activity were subjected to chemical identification of signaling molecules by high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS. For each AHL-producing strain, we found at least four different AHLs, corresponding to N-hexanoyl-DL-homoserine lactone (C6, N-(3-oxodecanoyl-L-homoserine lactone (3OC10, N-(3-oxododecanoyl-L-homoserine lactone (3OC12, and N-(3-oxotetradecanoyl-L-homoserine lactone (3OC14. Biological roles of 3OC10, 3OC12, and 3OC14 AHLs

  8. Antileishmanial Activity of Aldonamides and N-Acyl-Diamine Derivatives

    Directory of Open Access Journals (Sweden)

    Elaine S. Coimbra

    2008-01-01

    Full Text Available A number of lipophilic N-acyl-diamines and aldonamides have been synthesized and tested for their in vitro antiproliferative activity against Leishmania amazonensis and L. chagasi. Ribonamides, having one amino group, displayed good to moderate inhibition of parasite growth. The best result was obtained for compounds 10 and 15 with IC50 against L. chagasi below 5 μM.

  9. Lubricity characteristics of seed oils modified by acylation

    Science.gov (United States)

    Chemically modified seed oils via acylation of epoxidized and polyhydroxylated derivatives were investigated for their potential as candidates for lubrication. The native oil was preliminarily epoxidized and ring-opened in a one-pot reaction using formic acid-H2O2 followed by aqueous HCl treatment t...

  10. Direct acylation of aryl bromides with aldehydes by palladium catalysis.

    Science.gov (United States)

    Ruan, Jiwu; Saidi, Ourida; Iggo, Jonathan A; Xiao, Jianliang

    2008-08-13

    A new protocol for the direct acylation of aryl bromides with aldehydes is established. It appears to involve palladium-amine cooperative catalysis, affording synthetically important alkyl aryl ketones in moderate to excellent yields in a straightforward manner, and broadening the scope of metal-catalyzed coupling reactions.

  11. Medium-chain acyl-CoA dehydrogenase deficiency

    DEFF Research Database (Denmark)

    Waddell, Leigh; Wiley, Veronica; Carpenter, Kevin

    2006-01-01

    The fatty acid oxidation disorder most commonly identified by tandem mass spectrometry newborn screening is the potentially fatal medium-chain acyl-CoA dehydrogenase deficiency (MCAD). In clinically presenting cases, 80% are homozygous for the common mutation, c.985A > G and 18% heterozygous. We ...

  12. The Acylation State of Surface Lipoproteins of Mollicute Acholeplasma laidlawii*

    Science.gov (United States)

    Serebryakova, Marina V.; Demina, Irina A.; Galyamina, Maria A.; Kondratov, Ilya G.; Ladygina, Valentina G.; Govorun, Vadim M.

    2011-01-01

    Acylation of the N-terminal Cys residue is an essential, ubiquitous, and uniquely bacterial posttranslational modification that allows anchoring of proteins to the lipid membrane. In Gram-negative bacteria, acylation proceeds through three sequential steps requiring lipoprotein diacylglyceryltransferase, lipoprotein signal peptidase, and finally lipoprotein N-acyltransferase. The apparent lack of genes coding for recognizable homologs of lipoprotein N-acyltransferase in Gram-positive bacteria and Mollicutes suggests that the final step of the protein acylation process may be absent in these organisms. In this work, we monitored the acylation state of eight major lipoproteins of the mollicute Acholeplasma laidlawii using a combination of standard two-dimensional gel electrophoresis protein separation, blotting to nitrocellulose membranes, and MALDI-MS identification of modified N-terminal tryptic peptides. We show that for each A. laidlawii lipoprotein studied a third fatty acid in an amide linkage on the N-terminal Cys residue is present, whereas diacylated species were not detected. The result thus proves that A. laidlawii encodes a lipoprotein N-acyltransferase activity. We hypothesize that N-acyltransferases encoded by genes non-homologous to N-acyltransferases of Gram-negative bacteria are also present in other mollicutes and Gram-positive bacteria. PMID:21540185

  13. A covalent adduct of MbtN, an acyl-ACP dehydrogenase from Mycobacterium tuberculosis, reveals an unusual acyl-binding pocket.

    Science.gov (United States)

    Chai, Ai-Fen; Bulloch, Esther M M; Evans, Genevieve L; Lott, J Shaun; Baker, Edward N; Johnston, Jodie M

    2015-04-01

    Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis. Access to iron in host macrophages depends on iron-chelating siderophores called mycobactins and is strongly correlated with Mtb virulence. Here, the crystal structure of an Mtb enzyme involved in mycobactin biosynthesis, MbtN, in complex with its FAD cofactor is presented at 2.30 Å resolution. The polypeptide fold of MbtN conforms to that of the acyl-CoA dehydrogenase (ACAD) family, consistent with its predicted role of introducing a double bond into the acyl chain of mycobactin. Structural comparisons and the presence of an acyl carrier protein, MbtL, in the same gene locus suggest that MbtN acts on an acyl-(acyl carrier protein) rather than an acyl-CoA. A notable feature of the crystal structure is the tubular density projecting from N(5) of FAD. This was interpreted as a covalently bound polyethylene glycol (PEG) fragment and resides in a hydrophobic pocket where the substrate acyl group is likely to bind. The pocket could accommodate an acyl chain of 14-21 C atoms, consistent with the expected length of the mycobactin acyl chain. Supporting this, steady-state kinetics show that MbtN has ACAD activity, preferring acyl chains of at least 16 C atoms. The acyl-binding pocket adopts a different orientation (relative to the FAD) to other structurally characterized ACADs. This difference may be correlated with the apparent ability of MbtN to catalyse the formation of an unusual cis double bond in the mycobactin acyl chain.

  14. Evolution of the acyl-CoA binding protein (ACBP)

    Science.gov (United States)

    Burton, Mark; Rose, Timothy M.; Færgeman, Nils J.; Knudsen, Jens

    2005-01-01

    Acyl-CoA-binding protein (ACBP) is a 10 kDa protein that binds C12–C22 acyl-CoA esters with high affinity. In vitro and in vivo experiments suggest that it is involved in multiple cellular tasks including modulation of fatty acid biosynthesis, enzyme regulation, regulation of the intracellular acyl-CoA pool size, donation of acyl-CoA esters for β-oxidation, vesicular trafficking, complex lipid synthesis and gene regulation. In the present study, we delineate the evolutionary history of ACBP to get a complete picture of its evolution and distribution among species. ACBP homologues were identified in all four eukaryotic kingdoms, Animalia, Plantae, Fungi and Protista, and eleven eubacterial species. ACBP homologues were not detected in any other known bacterial species, or in archaea. Nearly all of the ACBP-containing bacteria are pathogenic to plants or animals, suggesting that an ACBP gene could have been acquired from a eukaryotic host by horizontal gene transfer. Many bacterial, fungal and higher eukaryotic species only harbour a single ACBP homologue. However, a number of species, ranging from protozoa to vertebrates, have evolved two to six lineage-specific paralogues through gene duplication and/or retrotransposition events. The ACBP protein is highly conserved across phylums, and the majority of ACBP genes are subjected to strong purifying selection. Experimental evidence indicates that the function of ACBP has been conserved from yeast to humans and that the multiple lineage-specific paralogues have evolved altered functions. The appearance of ACBP very early on in evolution points towards a fundamental role of ACBP in acyl-CoA metabolism, including ceramide synthesis and in signalling. PMID:16018771

  15. Ethanol metabolism modifies hepatic protein acylation in mice.

    Directory of Open Access Journals (Sweden)

    Kristofer S Fritz

    Full Text Available Mitochondrial protein acetylation increases in response to chronic ethanol ingestion in mice, and is thought to reduce mitochondrial function and contribute to the pathogenesis of alcoholic liver disease. The mitochondrial deacetylase SIRT3 regulates the acetylation status of several mitochondrial proteins, including those involved in ethanol metabolism. The newly discovered desuccinylase activity of the mitochondrial sirtuin SIRT5 suggests that protein succinylation could be an important post-translational modification regulating mitochondrial metabolism. To assess the possible role of protein succinylation in ethanol metabolism, we surveyed hepatic sub-cellular protein fractions from mice fed a control or ethanol-supplemented diet for succinyl-lysine, as well as acetyl-, propionyl-, and butyryl-lysine post-translational modifications. We found mitochondrial protein propionylation increases, similar to mitochondrial protein acetylation. In contrast, mitochondrial protein succinylation is reduced. These mitochondrial protein modifications appear to be primarily driven by ethanol metabolism, and not by changes in mitochondrial sirtuin levels. Similar trends in acyl modifications were observed in the nucleus. However, comparatively fewer acyl modifications were observed in the cytoplasmic or the microsomal compartments, and were generally unchanged by ethanol metabolism. Using a mass spectrometry proteomics approach, we identified several candidate acetylated, propionylated, and succinylated proteins, which were enriched using antibodies against each modification. Additionally, we identified several acetyl and propionyl lysine residues on the same sites for a number of proteins and supports the idea of the overlapping nature of lysine-specific acylation. Thus, we show that novel post-translational modifications are present in hepatic mitochondrial, nuclear, cytoplasmic, and microsomal compartments and ethanol ingestion, and its associated

  16. Fatty acyl-CoA reductases of birds

    Directory of Open Access Journals (Sweden)

    Hellenbrand Janine

    2011-12-01

    Full Text Available Abstract Background Birds clean and lubricate their feathers with waxes that are produced in the uropygial gland, a holocrine gland located on their back above the tail. The type and the composition of the secreted wax esters are dependent on the bird species, for instance the wax ester secretion of goose contains branched-chain fatty acids and unbranched fatty alcohols, whereas that of barn owl contains fatty acids and alcohols both of which are branched. Alcohol-forming fatty acyl-CoA reductases (FAR catalyze the reduction of activated acyl groups to fatty alcohols that can be esterified with acyl-CoA thioesters forming wax esters. Results cDNA sequences encoding fatty acyl-CoA reductases were cloned from the uropygial glands of barn owl (Tyto alba, domestic chicken (Gallus gallus domesticus and domestic goose (Anser anser domesticus. Heterologous expression in Saccharomyces cerevisiae showed that they encode membrane associated enzymes which catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. By feeding studies of transgenic yeast cultures and in vitro enzyme assays with membrane fractions of transgenic yeast cells two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol and accepted substrates in the range between 14 and 18 carbon atoms, whereas the FAR2 group preferred stearoyl-CoA and accepted substrates between 16 and 20 carbon atoms. Expression studies with tissues of domestic chicken indicated that FAR transcripts were not restricted to the uropygial gland. Conclusion The data of our study suggest that the identified and characterized avian FAR isozymes, FAR1 and FAR2, can be involved in wax ester biosynthesis and in other pathways like ether lipid synthesis.

  17. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence

    Science.gov (United States)

    Flynn, Padrig B.; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P.; Elliott, Christopher T.; Laverty, Garry; Gorman, Sean P.; Graham, William G.; Gilmore, Brendan F.

    2016-01-01

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30–60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa. PMID:27242335

  18. Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence.

    Science.gov (United States)

    Flynn, Padrig B; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P; Elliott, Christopher T; Laverty, Garry; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2016-05-31

    The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30-60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa.

  19. Estimation of spatial distribution of quorum sensing signaling in sequencing batch biofilm reactor (SBBR) biofilms.

    Science.gov (United States)

    Wang, Jinfeng; Ding, Lili; Li, Kan; Huang, Hui; Hu, Haidong; Geng, Jinju; Xu, Ke; Ren, Hongqiang

    2017-08-28

    Quorum sensing (QS) signaling, plays a significant role in regulating formation of biofilms in the nature; however, little information about the occurrence and distribution of quorum sensing molecular in the biofilm of carriers has been reported. In this study, distribution of QS signaling molecules (the acylated homoserine lactones-AHLs, and AI-2), extracellular polymeric substances (EPS) and the mechanical properties in sequencing batch biofilm reactor (SBBR) biofilms have been investigated. Using increased centrifugal force, the biofilms were detached into different fractions. The AHLs ranged from 5.2ng/g to 98.3ng/g in different fractions of biofilms, and N-decanoyl-dl-homoserine lactone (C10-HSL) and N-dodecanoyl-dl-homoserine lactone (C12-HSL) in the biofilms obtained at various centrifugal forces displayed significant differences (pbiofilms ranged from 79.2ng/g to 98.3ng/g. Soluble EPS and loosely bound EPS content in the different fractions of biofilms displayed significant positive relationship with the distribution of C12-HSL (r=0.86, pbiofilms were positively related with AHLs with 22.76% was significantly positively (pBiofilm adhesion and compliance was the strongest in the tightly-bound biofilm, the weakest in the supernatant/surface biofilm, which was in accordance with the distribution of C12 HSL(r=0.77, pbiofilm application. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. 1,3-Dipolar cycloaddition of a cyclic nitrone derived from 2-deoxy-D-ribose to α,β-unsaturated lactones: An entry to carbapenem antibiotics.

    Science.gov (United States)

    Pieczykolan, Michał; Staszewska-Krajewska, Olga; Furman, Bartłomiej; Chmielewski, Marek

    2016-10-04

    1,3-Dipolar cycloadditions of 2-deoxy-D-ribose-derived L-threo five-membered cyclic nitrone to α,β-unsaturated γ- and δ-lactones were investigated. Cycloadducts obtained from δ-lactones, after NO bond cleavage, opening of the lactone ring, and protection of hydroxyl groups were subjected to β-lactam ring formation by using Mukaiyama's salt. Cycloadducts from γ-lactones subjected to the same reaction sequence undergo β-elimination of a water molecule to provide pyrrolidine-substituted unsaturated γ-lactones. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Ulubelenolide: A New triterpene lactone from Tanacetum chiliophyllum (Fisch. & Mey. var. monocephalum Grierson

    Directory of Open Access Journals (Sweden)

    Kaan Polatoğlu

    2015-04-01

    Full Text Available A further investigation on Tanacetum chilliophyllum var. monocephalum ethyl acetate extract afforded a new triterpene lactone Ulubelenolide (olean-12-ene-3β,10β-olide (1.The structure of (1 was determined with spectral analysis including FTIR, 1H, 13C NMR, APT, DEPT, COSY, HMQC, HMBC, and APCI-MS.

  2. Ficuschlorins A - D, lactone Chlorins from the leaves of ficus microcarpa.

    Science.gov (United States)

    Lin, Huan-You; Chiu, Hsi-Lin; Lan, Yu-Hsuang; Tzeng, Chih-Ying; Lee, Tzong-Huei; Lee, Ching-Kuo; Shao, Yi-Yuan; Chen, Chiy-Rong; Chang, Chi-I; Kuo, Yueh-Hsiung

    2011-09-01

    Four new lactone chlorins, ficuschlorins A - D (1-4, resp.), and six known pheophytins were isolated from the leaves of Ficus microcarpa. The structures of these compounds were determined by 1D- and 2D-NMR spectroscopy, and other techniques. New natural pheophytins were rarely obtained. In the past ten years, only three new pheophytins were isolated from natural sources.

  3. Detection of N-acylhomoserine lactones in lung tissues of mice infected with Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Wu, H; Song, Z; Hentzer, Morten

    2000-01-01

    The pathogenesis of Pseudomonas aeruginosa is associated with expression of virulence factors, many of which are controlled by two N:-acylhomoserine lactone (AHL)-based quorum-sensing systems. Escherichia coli strains equipped with a luxR-based monitor system expressing green fluorescent protein...

  4. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K; Hentzer, Morten; Geisenberger, O

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co-ordinate expression of virulence factors with the forma...

  5. Cytotoxic and antibacterial activities of sesquiterpene lactones isolated from Tanacetum praeteritum subsp praeteritum

    NARCIS (Netherlands)

    Goren, N; Woerdenbag, HJ; BozokJohansson, C

    1996-01-01

    Ten sesquiterpene lactones and one sesquiterpene isolated from Tanacetum praeteritum subsp. praeteritum: 1 alpha,6 alpha-dihydroxyisocostic acid methyl ester (2), 1 alpha-hydroxy-1-deoxoarglanine (3), douglanin (5), santamarin (6), reynosin (7), 1-epi-tatridin B (8), ludovicin A (10), armexin (12),

  6. Reactions of Three Lactones with Cl, OD, and O3

    DEFF Research Database (Denmark)

    Ausmeel, Stina; Andersen, Cecilie Lindholm; Nielsen, Ole John

    2017-01-01

    for reactions of the lactones with Cl. In the presence of O2 the products are formic acid (HCOOH), formyl chloride (CHClO), and phosgene (CCl2O), and also maleic anhydride (C2H2(CO)2O) for 2(5H)-F. In addition both reactions produced a number of unidentified products that likely belong to molecules...

  7. Properties of acid casein gels made by acidification with Glucono-δ-lactone. 1. Rheological properties

    NARCIS (Netherlands)

    Lucey, J.A.; Vliet, van T.; Grolle, K.; Geurts, T.; Walstra, P.

    1997-01-01

    The effects of gelation temperature (20, 30 or 40 °C), assay temperature, concentration of glucono-δ-lactone (GDL) added, and NaCl concentration on the rheological properties of acid casein gels were studied at small and large deformations. Gels prepared at a high incubation temperature had very low

  8. Haemonchus contortus P-glycoprotein-2: in situ localisation and characterisation of macrocyclic lactone transport.

    Science.gov (United States)

    Godoy, Pablo; Lian, Jing; Beech, Robin N; Prichard, Roger K

    2015-01-01

    Haemonchus contortus is a veterinary nematode that infects small ruminants, causing serious decreases in animal production worldwide. Effective control through anthelmintic treatment has been compromised by the development of resistance to these drugs, including the macrocyclic lactones. The mechanisms of resistance in H. contortus have yet to be established but may involve efflux of the macrocyclic lactones by nematode ATP-binding-cassette transporters such as P-glycoproteins. Here we report the expression and functional activity of H. contortus P-glycoprotein 2 expressed in mammalian cells and characterise its interaction with the macrocyclic lactones, ivermectin, abamectin and moxidectin. The ability of H. contortus P-glycoprotein 2 to transport different fluorophore substrates was markedly inhibited by ivermectin and abamectin in a dose-dependent and saturable way. The profile of transport inhibition by moxidectin was markedly different. H. contortus P-glycoprotein 2 was expressed in the pharynx, the first portion of the worm's intestine and perhaps in adjacent nervous tissue, suggesting a role for this gene in regulating the uptake of avermectins and in protecting nematode tissues from the effects of macrocyclic lactone anthelmintic drugs. H. contortus P-glycoprotein 2 may thus contribute to resistance to these drugs in H. contortus.

  9. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K.; Hentzer, Morten; Geisenberger, O.;

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co- ordinate expression of virulence factors with the form...

  10. The molecular receptive range of a lactone receptor in Anopheles gambiae.

    Science.gov (United States)

    Pask, Gregory M; Romaine, Ian M; Zwiebel, Laurence J

    2013-01-01

    In an environment filled with a complex spectrum of chemical stimuli, insects rely on the specificity of odorant receptors (ORs) to discern odorants of ecological importance. In nature, cyclic esters, or lactones, represent a common class of semiochemicals that exhibit a range of diversity through ring size and substituents, as well as stereochemistry. We have used heterologous expression to explore the lactone sensitivity of AgOr48, an odorant-sensitive OR from the principal malaria vector mosquito, Anopheles gambiae. Voltage clamp and calcium-imaging experiments revealed that AgOr48 is particularly sensitive to changes in the size of the lactone ring and in the length of the carbon chain substituent. In addition, the two enantiomers of a strong agonist, δ-decalactone, elicited significantly different potency values, implicating AgOr48 as an enantioselective odorant receptor. Investigation of the molecular receptive range of this lactone receptor may contribute to a greater understanding of ligand-OR interactions and provide insight into the chemical ecology of An. gambiae.

  11. SELECTIVE HYDROGENATION OF ANHYDRIDES TO LACTONES UNDER SUPERCRITICAL CARBON DIOXIDE MEDIUM

    Science.gov (United States)

    Selective Hydrogenation of Anhydrides to Lactones Under Supercritical Carbon Dioxide MediumEndalkachew Sahle-Demessie Unnikrishnan R PillaiU.S. EPA , 26 W. Martin Luther King Dr. Cincinnati, OH 45268 Phone: 513-569-7739Fax: 513-569-7677Abstract:Hydrogenat...

  12. Concurrent and supercritical fluid chromatographic analysis of Terpene Lactones and ginkolic acids in Ginko biloba

    Science.gov (United States)

    Supercritical fluid chromatography was used to resolve and determine ginkgolic acids (GAs) and terpene lactones concurrently in ginkgo plant materials and commercial dietary supplements. Analysis of GAs (C13:0, C15:0, C15:1 and C17:1) was carried out by ESI (-) mass detection. The ESI (-) spectra of...

  13. delta-Lactone from Oedogonium capillare and their effects on rat ileum.

    Science.gov (United States)

    Perez Gutierrez, Rosa Martha; Rosario Vargas, Solis; Martinez Martinez, Francisco; Garcia Baez, Efren; Figueroa Torres, Guadalupe

    2006-03-01

    Antispasmodic activity-guided fractionation together with chemical analysis led to the isolation of one novel delta-lactone named oedogonolide from Oedogonium capillare. Identification was based on spectroscopic methods. The oedogonolide produces a significant antispasmodic effect on the contractions of the rat ileum induced by acetylcholine, histamine and barium chloride.

  14. Determination of ursolic acid and ursolic acid lactone in the leaves of Eucalyptus tereticornis by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, Anupam; Srivastava, Santosh Kumar [Analytical Chemistry Division, Central Institute of Medicinal and Aromatic Plants, Lucknow (India)

    2012-03-15

    A simple isocratic HPLC method has been developed for the simultaneous quantification of two bioactive triterpenes, ursolic acid and ursolic acid lactone in E. tereticornis leaves. Samples were analyzed on RP-18 (4.6 x 250 mm, 5 {sup m}u{sup m}) column with methanol and water acidified to pH 3.5 with TFA (88:12) at 210 nm. The method was validated and applied for the simultaneous quantification of the individual triterpenes in E. tereticornis extract. The calibration curves were linear over a concentration range of 0.05-0.3 mg mL{sup -1} (r = 0.999 and 0.998, respectively). The limits of detection and quantification were 0.190 and 0.644 {mu}g for ursolic acid, and 0.176 and 0.587 {mu}g for ursolic acid lactone, while the percentage recoveries were 97.32 and 96.23% for ursolic acid and ursolic acid lactone, respectively. This is the first report on the HPLC method of ursolic acid lactone with high precision and accuracy. (author)

  15. A new cassane diterpenoid lactone from the seed of Caesalptma minax

    Institute of Scientific and Technical Information of China (English)

    Yan Cheng; Li Yan Ma; Jian Hua Miao; Xu Dong Xu; Jing Quan Yuan; Jun Shan Yang

    2009-01-01

    A new cassane diterpenoid lactone was isolated from the seed of Caesalpinia minax.On the basis of spectral evidences,its structure was established as 12α-methoxyl,5α,14β-dihydroxy-1α,6α,7β-triacetoxycass-13(15)-en-16,12-olide.

  16. Lactones with Methylcyclohexane Systems Obtained by Chemical and Microbiological Methods and Their Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Małgorzata Grabarczyk

    2015-02-01

    Full Text Available Eight new lactones (δ-chloro-, δ-bromo- and δ-iodo-γ-lactones, each with a methylcyclohexane ring, were obtained by chemical means from (4-methylcyclohex-2-en-1-yl acetic acid or (6-methylcyclohex-2-en-1-yl acetic acid. Whole cells of ten fungal strains (Fusarium species, Syncephalastrum racemosum and Botrytis cinerea were tested on their ability to convert these lactones into other products. Some of the tested fungal strains transformed chloro-, bromo- and iodolactone with a methyl group at C-5 into 2-hydroxy-5-methyl-9-oxabicyclo[4.3.0]nonan-8-one during hydrolytic dehalogenation. When the same lactones had the methyl group at C-3, no structural modifications of halolactones were observed. In most cases, the optical purity of the product was low or medium, with the highest rate for chlorolactone (45.4% and iodolactone (45.2% and 47.6%. All of the obtained compounds were tested with reference to their smell. Seven halolactones and the hydroxylactone obtained via biotransformation of halolactones with 5-methylcyclohexane ring were examined for their antimicrobial activity. These compounds were capable of inhibiting growth of some bacteria, yeasts and fungi.

  17. Developmental and Environmental Effects on Sesquiterpene Lactones in Cultivated Arnica montana L.

    Science.gov (United States)

    Todorova, Milka; Trendafilova, Antoaneta; Vitkova, Antonina; Petrova, Maria; Zayova, Ely; Antonova, Daniela

    2016-08-01

    The amount of sesquiterpene lactones and the lactone profile of Arnica montana L. in flowering and seed formation stages in vitro and in vivo propagated from seeds of German, Ukrainian, and Austrian origin and grown in two experimental fields were studied. It was found that in vitro propagated 2-year plants in full flowering stage accumulated higher amount of lactones in comparison to in vivo propagated 3-year plants and to the seed formation stage, respectively. Helenalins predominated in in vivo propagated 2-year or in vitro propagated 3-year plants. 2-Methylbutyrate (2MeBu) was the principal ester in the samples with prevalence of helenalins, while isobutyrate (iBu) was the major one in the samples with predominance of 11,13-dihydrohelenalins. The results revealed that the environmental conditions on Vitosha Mt. are more suitable for cultivation of A. montana giving higher content of lactones.

  18. Paraoxonase (PON1 and PON3 polymorphisms: impact on liver expression and atorvastatin-lactone hydrolysis

    Directory of Open Access Journals (Sweden)

    Stephan eRiedmaier

    2011-07-01

    Full Text Available Atorvastatin δ-lactone, a major, pharmacologically inactive metabolite, has been associated with toxicity. In a previous study we showed that polymorphisms of UGT1A3 influence atorvastatin δ-lactone formation. Here we investigated the reverse reaction, atorvastatin δ-lactone hydrolysis, in a human liver bank. Screening of microarray data revealed paraoxonases PON1 and PON3 among 17 candidate esterases. Microsomal δ-lactone hydrolysis was significantly correlated to PON1 and PON3 protein (rs=0.60; rs=0.62, respectively; P<0.0001. PON1 and PON3 were strongly correlated to each other (rs=0.60 but PON1 was shown to be more extensively glycosylated than PON3. In addition a novel splice variant of PON3 was identified. Genotyping of 40 polymorphisms within the PON-locus identified PON1 promoter polymorphisms (-108T>C, -832G>A, -1741G>A and a tightly linked group of PON3 polymorphisms (-4984A>G, -4105G>A, -1091A>G, -746C>T and F21F to be associated with changes in atorvastatin δ-lactone hydrolysis and expression of PON1 but not PON3. However, carriers of the common PON1 polymorphisms L55M or Q192R showed no difference in δ-lactone hydrolysis or PON expression. Haplotype analysis revealed decreased δ-lactone hydrolysis in carriers of the most common haplotype *1 compared to carriers of haplotypes *2, *3, *4 and *7. Analysis of non-genetic factors showed association of hepatocellular and cholangiocellular carcinoma with decreased PON1 and PON3 expression, respectively. Increased C-reactive protein and γ-glutamyl transferase levels were associated with decreased protein expression of both enzymes, and increased bilirubin levels, cholestasis and pre-surgical exposure to omeprazole or pantoprazole were related to decreased PON3 protein. In conclusion, PON-locus polymorphisms affect PON1 expression whereas non-genetic factors have an effect on PON1 and PON3 expression. This may influence response to therapy or adverse events in statin treatment.

  19. Selective enzymatic hydrolysis of chlorogenic acid lactones in a model system and in a coffee extract. Application to reduction of coffee bitterness.

    Science.gov (United States)

    Kraehenbuehl, Karin; Page-Zoerkler, Nicole; Mauroux, Olivier; Gartenmann, Karin; Blank, Imre; Bel-Rhlid, Rachid

    2017-03-01

    Chlorogenic acid lactones have been identified as key contributors to coffee bitterness. These compounds are formed during roasting by dehydration and cyclization of their precursors, the chlorogenic acids (CGAs). In the present study, we investigated an approach to decompose these lactones in a selective way without affecting the positive coffee attributes developed during roasting. A model system composed of (3-caffeoylquinic acid lactone (3-CQAL), 4- caffeoyl quinic acid lactone (4-CQAL), and 4-feruloylquinic acid lactone (4-FQAL)) was used for the screening of enzymes before treatment of the coffee extracts. Hog liver esterase (HLE) hydrolyzed chlorogenic acid lactones (CQALs, FQALs) selectively, while chlorogenate esterase hydrolyzed all chlorogenic acids (CQAs, FQAs) and their corresponding lactones (CQALs, FQALs) in a non-selective way. Enzymatically treated coffee samples were evaluated for their bitterness by a trained sensory panel and were found significantly less bitter than the untreated samples.

  20. Mode of Action of the Sesquiterpene Lactones Psilostachyin and Psilostachyin C on Trypanosoma cruzi

    Science.gov (United States)

    Papademetrio, Daniela; Batlle, Alcira; Martino, Virginia S.; Frank, Fernanda M.; Lombardo, María E.

    2016-01-01

    Trypanosoma cruzi is the causative agent of Chagas’ disease, which is a major endemic disease in Latin America and is recognized by the WHO as one of the 17 neglected tropical diseases in the world. Psilostachyin and psilostachyin C, two sesquiterpene lactones isolated from Ambrosia spp., have been demonstrated to have trypanocidal activity. Considering both the potential therapeutic targets present in the parasite, and the several mechanisms of action proposed for sesquiterpene lactones, the aim of this work was to characterize the mode of action of psilostachyin and psilostachyin C on Trypanosoma cruzi and to identify the possible targets for these molecules. Psilostachyin and psilostachyin C were isolated from Ambrosia tenuifolia and Ambrosia scabra, respectively. Interaction of sesquiterpene lactones with hemin, the induction of oxidative stress, the inhibition of cruzipain and trypanothione reductase and their ability to inhibit sterol biosynthesis were evaluated. The induction of cell death by apoptosis was also evaluated by analyzing phosphatidylserine exposure detected using annexin-V/propidium iodide, decreased mitochondrial membrane potential, assessed with Rhodamine 123 and nuclear DNA fragmentation evaluated by the TUNEL assay. Both STLs were capable of interacting with hemin. Psilostachyin increased about 5 times the generation of reactive oxygen species in Trypanosoma cruzi after a 4h treatment, unlike psilostachyin C which induced an increase in reactive oxygen species levels of only 1.5 times. Only psilostachyin C was able to inhibit the biosynthesis of ergosterol, causing an accumulation of squalene. Both sesquiterpene lactones induced parasite death by apoptosis. Upon evaluating the combination of both compounds, and additive trypanocidal effect was observed. Despite their structural similarity, both sesquiterpene lactones exerted their anti-T. cruzi activity through interaction with different targets. Psilostachyin accomplished its

  1. Mode of Action of the Sesquiterpene Lactones Psilostachyin and Psilostachyin C on Trypanosoma cruzi.

    Science.gov (United States)

    Sülsen, Valeria P; Puente, Vanesa; Papademetrio, Daniela; Batlle, Alcira; Martino, Virginia S; Frank, Fernanda M; Lombardo, María E

    2016-01-01

    Trypanosoma cruzi is the causative agent of Chagas' disease, which is a major endemic disease in Latin America and is recognized by the WHO as one of the 17 neglected tropical diseases in the world. Psilostachyin and psilostachyin C, two sesquiterpene lactones isolated from Ambrosia spp., have been demonstrated to have trypanocidal activity. Considering both the potential therapeutic targets present in the parasite, and the several mechanisms of action proposed for sesquiterpene lactones, the aim of this work was to characterize the mode of action of psilostachyin and psilostachyin C on Trypanosoma cruzi and to identify the possible targets for these molecules. Psilostachyin and psilostachyin C were isolated from Ambrosia tenuifolia and Ambrosia scabra, respectively. Interaction of sesquiterpene lactones with hemin, the induction of oxidative stress, the inhibition of cruzipain and trypanothione reductase and their ability to inhibit sterol biosynthesis were evaluated. The induction of cell death by apoptosis was also evaluated by analyzing phosphatidylserine exposure detected using annexin-V/propidium iodide, decreased mitochondrial membrane potential, assessed with Rhodamine 123 and nuclear DNA fragmentation evaluated by the TUNEL assay. Both STLs were capable of interacting with hemin. Psilostachyin increased about 5 times the generation of reactive oxygen species in Trypanosoma cruzi after a 4h treatment, unlike psilostachyin C which induced an increase in reactive oxygen species levels of only 1.5 times. Only psilostachyin C was able to inhibit the biosynthesis of ergosterol, causing an accumulation of squalene. Both sesquiterpene lactones induced parasite death by apoptosis. Upon evaluating the combination of both compounds, and additive trypanocidal effect was observed. Despite their structural similarity, both sesquiterpene lactones exerted their anti-T. cruzi activity through interaction with different targets. Psilostachyin accomplished its antiparasitic

  2. Self-structuring foods based on acid-sensitive low and high acyl mixed gellan systems to impact on satiety

    OpenAIRE

    2014-01-01

    This study investigated the in vitro acid-induced gelation of mixed systems of two biopolymers; low acyl and high acyl gellan gum. Rheological and texture analysis showed that these mixed gels displayed textures that lay between the material properties exhibited for the low and high acyl variants. DSC analysis showed that mixtures of the low acyl and high acyl forms exhibit two separate conformational transitions at temperatures coincident with each of the individual biopolymers. Various meta...

  3. Functional characterization of triclosan-resistant enoyl-acyl-carrier protein reductase (FabV in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Yong-Heng Huang

    2016-11-01

    Full Text Available Pseudomonas aeruginosa is extremely resistant to triclosan. Previous studies have shown that P. aeruginosa encodes a triclosan-resistant enoyl-acyl-carrier protein reductase (ENR, FabV, and that deletion of fabV causes P. aeruginosa to be extremely sensitive to triclosan. In this report, we complemented a P. aeruginosa fabV deletion strain with several triclosan-resistant ENR encoding genes, including Vibrio cholera fabV, Bacillus subtilis fabL and Enterococcus faecalis fabK. All complemented strains restored triclosan resistance to the level of the wild-type strain, which confirmed that triclosan-resistant ENR allows P. aeruginosa to be extremely resistant to triclosan. Moreover, fabV exhibits pleiotropic effects. Deletion of fabV led P. aeruginosa to show attenuated swarming motility, decreased rhamnolipid, pyoverdine and acylhomoserine lactones (AHLs production. Complementation of the fabV mutant with any one ENR encoding gene could restore these features to some extent, in comparison with the wild-type strain. Furthermore, we found that addition of exogenous AHLs could restore to the fabV mutant strain the ability to swarm on semisolid plates and to produce more virulence factors than the fabV mutant strain. These findings indicate that deletion of fabV reduced the activity of ENR in P. aeruginosa, decreased fatty acid synthesis, and subsequently depressed the production of AHLs and other virulence factors, which finally may led to a reduction in the pathogenicity of P. aeruginosa. Therefore, fabV should be an ideal target for the control of P. aeruginosa infectivity.

  4. Lipase-catalyzed biodiesel synthesis with different acyl acceptors

    Directory of Open Access Journals (Sweden)

    Ognjanović Nevena D.

    2008-01-01

    Full Text Available Biodiesel is an alternative fuel for diesel engine that is environmentally acceptable. Conventionally, biodiesel is produced by transesterification of triglycerides and short alcohols in the presence of an acid or an alkaline catalyst. There are several problems associated with this kind of production that can be resolved by using lipase as the biocatalyst. The aim of the present work was to investigate novel acyl acceptors for biodiesel production. 2-Propanol and n-butanol have a less negative effect on lipase stability, and they also improve low temperature properties of the fuel. However, excess alcohol leads to inactivation of the enzyme, and glycerol, a major byproduct, can block the immobilized enzyme, resulting in low enzymatic activity. This problem was solved by using methyl acetate as acyl acceptor. Triacetylglycerol is produced instead of glycerol, and it has no negative effect on the activity of the lipase.

  5. New acylated anthocyanins from purple yam and their antioxidant activity.

    Science.gov (United States)

    Moriya, Chiemi; Hosoya, Takahiro; Agawa, Sayuri; Sugiyama, Yasumasa; Kozone, Ikuko; Shin-Ya, Kazuo; Terahara, Norihiko; Kumazawa, Shigenori

    2015-01-01

    Purple yam (Dioscorea alata L.), which is widely distributed in tropical and subtropical regions, is characterized by its color and viscosity. Previous studies have shown that purple yams contain a variety of acylated anthocyanins that exhibit higher levels of antioxidant activity than the corresponding nonacylated compounds. In this study, the pigments found in purple yams from the Philippines (D. alata) were isolated and evaluated in terms of antioxidant activity. Four new acylated anthocyanins, alanins (1-4) were isolated from the MeOH extracts of purple yam, which were subsequently determined to be cyanidin (1, 2, and 4) and peonidin (3) type compounds, along with four known anthocyanins (5-8). The structures of 1-4 were determined by spectroscopic methods, including NMR and MS analyses. The antioxidant activities of anthocyanins 1-8 were investigated using oxygen radical absorbing capacity and ferric reducing antioxidant power assays.

  6. C-Metalated Nitriles: Electrophile-Dependent Alkylations and Acylations

    Science.gov (United States)

    Fleming, Fraser F.; Zhang, Zhiyu; Wei, Guoqing; Steward, Omar W.

    2006-01-01

    Sequential carbonyl addition-conjugate addition of Grignard reagents to 3-oxocyclohex-1-ene-1-carbonitrile generates C-magnesiated nitriles whose alkylation stereoselectivities intimately depend on the nature of the electrophile. Alkylating these C-magnesiated nitriles with alkyl halides, sulfonates, and unstrained ketones occur with retention of the C-Mg configuration, whereas aldehyde and acyl cyanide acylations proceed with inversion of stereochemistry. Mechanistic probes indicate that the stereoselectivity is controlled by stereoelectronic effects for most electrophiles except allylic, benzylic, and cyclopropyl halides where single electron transfer processes intervene. Screening numerous alkylations of C-magnesiated nitriles with a diverse range of electrophiles reveals the reaction scope and delineates the fundamental stereoelectronic effects responsible for the highly unusual electrophile-dependent alkylations. PMID:16468790

  7. Site-Selective Acylations with Tailor-Made Catalysts.

    Science.gov (United States)

    Huber, Florian; Kirsch, Stefan F

    2016-04-18

    The acylation of alcohols catalyzed by N,N-dimethylamino pyridine (DMAP) is, despite its widespread use, sometimes confronted with substrate-specific problems: For example, target compounds with multiple hydroxy groups may show insufficient selectivity for one hydroxyl, and the resulting product mixtures are hardly separable. Here we describe a concept that aims at tailor-made catalysts for the site-specific acylation. To this end, we introduce a catalyst library where each entry is constructed by connecting a variable and readily tuned peptide scaffold with a catalytically active unit based on DMAP. For selected examples, we demonstrate how library screening leads to the identification of optimized catalysts, and the substrates of interest can be converted with a markedly enhanced site-selectivity compared with only DMAP. Furthermore, substrate-optimized catalysts of this type can be used to selectively convert "their" substrate in the presence of structurally similar compounds, an important requisite for reactions with mixtures of substances.

  8. Vectorial acylation in Saccharomyces cerevisiae. Fat1p and fatty acyl-CoA synthetase are interacting components of a fatty acid import complex

    DEFF Research Database (Denmark)

    Zou, Zhiying; Tong, Fumin; Færgeman, Nils J.

    2003-01-01

    In Saccharomyces cerevisiae Fat1p and fatty acyl-CoA synthetase (FACS) are hypothesized to couple import and activation of exogenous fatty acids by a process called vectorial acylation. Molecular genetic and biochemical studies were used to define further the functional and physical interactions ...

  9. Glycosyltransferases from oat (Avena) implicated in the acylation of avenacins.

    Science.gov (United States)

    Owatworakit, Amorn; Townsend, Belinda; Louveau, Thomas; Jenner, Helen; Rejzek, Martin; Hughes, Richard K; Saalbach, Gerhard; Qi, Xiaoquan; Bakht, Saleha; Roy, Abhijeet Deb; Mugford, Sam T; Goss, Rebecca J M; Field, Robert A; Osbourn, Anne

    2013-02-01

    Plants produce a huge array of specialized metabolites that have important functions in defense against biotic and abiotic stresses. Many of these compounds are glycosylated by family 1 glycosyltransferases (GTs). Oats (Avena spp.) make root-derived antimicrobial triterpenes (avenacins) that provide protection against soil-borne diseases. The ability to synthesize avenacins has evolved since the divergence of oats from other cereals and grasses. The major avenacin, A-1, is acylated with N-methylanthranilic acid. Previously, we have cloned and characterized three genes for avenacin synthesis (for the triterpene synthase SAD1, a triterpene-modifying cytochrome P450 SAD2, and the serine carboxypeptidase-like acyl transferase SAD7), which form part of a biosynthetic gene cluster. Here, we identify a fourth member of this gene cluster encoding a GT belonging to clade L of family 1 (UGT74H5), and show that this enzyme is an N-methylanthranilic acid O-glucosyltransferase implicated in the synthesis of avenacin A-1. Two other closely related family 1 GTs (UGT74H6 and UGT74H7) are also expressed in oat roots. One of these (UGT74H6) is able to glucosylate both N-methylanthranilic acid and benzoic acid, whereas the function of the other (UGT74H7) remains unknown. Our investigations indicate that UGT74H5 is likely to be key for the generation of the activated acyl donor used by SAD7 in the synthesis of the major avenacin, A-1, whereas UGT74H6 may contribute to the synthesis of other forms of avenacin that are acylated with benzoic acid.

  10. Acylated flavonoids in callus cultures of Citrus aurantifolia.

    Science.gov (United States)

    Berhow, M A; Bennett, R D; Poling, S M; Vannier, S; Hidaka, T; Omura, M

    1994-07-01

    Two new acylated flavonol glycosides were isolated along with kaempferol 3-O-beta-rutinoside from 10-year-old callus cultures of Mexican lime. The structures of these new compounds are kaempferol 3-O-beta-D-glucopyranoside-6"-(3-hydroxy-3-methyl glutarate) and kaempferol 3-O-beta-D-glucopyranoside-6"-(3-hydroxy-3-methyl glutarate)-7-O-beta-D-glucopyranoside.

  11. A New Acylated Iridoid Glucoside from Avicennia marina

    Institute of Scientific and Technical Information of China (English)

    Yan FENG; Xiao Ming LI; Xiao Juan DUAN; Bin Gui WANG

    2006-01-01

    A new acylated iridoid glucoside, namely, 2'-O-(5-phenyl-2E, 4E-pentadienoyl)-mussaenosidic acid, was isolated from the aerial parts of the mangrove plant Avicennia marina.The structure of the new compound was established on the basis of various NMR spectroscopic analyses, including 2D NMR techniques (1H-1H COSY, HMQC, and HMBC) and HR-FAB-MS.This compound displayed moderate antioxidant activity.

  12. Glycosyltransferases from Oat (Avena) Implicated in the Acylation of Avenacins*

    Science.gov (United States)

    Owatworakit, Amorn; Townsend, Belinda; Louveau, Thomas; Jenner, Helen; Rejzek, Martin; Hughes, Richard K.; Saalbach, Gerhard; Qi, Xiaoquan; Bakht, Saleha; Roy, Abhijeet Deb; Mugford, Sam T.; Goss, Rebecca J. M.; Field, Robert A.; Osbourn, Anne

    2013-01-01

    Plants produce a huge array of specialized metabolites that have important functions in defense against biotic and abiotic stresses. Many of these compounds are glycosylated by family 1 glycosyltransferases (GTs). Oats (Avena spp.) make root-derived antimicrobial triterpenes (avenacins) that provide protection against soil-borne diseases. The ability to synthesize avenacins has evolved since the divergence of oats from other cereals and grasses. The major avenacin, A-1, is acylated with N-methylanthranilic acid. Previously, we have cloned and characterized three genes for avenacin synthesis (for the triterpene synthase SAD1, a triterpene-modifying cytochrome P450 SAD2, and the serine carboxypeptidase-like acyl transferase SAD7), which form part of a biosynthetic gene cluster. Here, we identify a fourth member of this gene cluster encoding a GT belonging to clade L of family 1 (UGT74H5), and show that this enzyme is an N-methylanthranilic acid O-glucosyltransferase implicated in the synthesis of avenacin A-1. Two other closely related family 1 GTs (UGT74H6 and UGT74H7) are also expressed in oat roots. One of these (UGT74H6) is able to glucosylate both N-methylanthranilic acid and benzoic acid, whereas the function of the other (UGT74H7) remains unknown. Our investigations indicate that UGT74H5 is likely to be key for the generation of the activated acyl donor used by SAD7 in the synthesis of the major avenacin, A-1, whereas UGT74H6 may contribute to the synthesis of other forms of avenacin that are acylated with benzoic acid. PMID:23258535

  13. Histone Acylation beyond Acetylation: Terra Incognita in Chromatin Biology

    Directory of Open Access Journals (Sweden)

    Sophie Rousseaux

    2015-04-01

    Full Text Available Histone acetylation, one of the first and best studied histone post-translational modifications (PTMs, as well as the factors involved in its deposition (writers, binding (readers and removal (erasers, have been shown to act at the heart of regulatory circuits controlling essential cellular functions. The identification of a variety of competing histone lysine-modifying acyl groups including propionyl, butyryl, 2-hydroxyisobutyryl, crotonyl, malonyl, succinyl and glutaryl, raises numerous questions on their functional significance, the molecular systems that manage their establishment, removal and interplay with the well-known acetylation-based mechanisms. Detailed and large-scale investigations of two of these new histone PTMs, crotonylation and 2-hydroxyisobutyrylation, along with histone acetylation, in the context of male genome programming, where stage-specific gene expression programs are switched on and off in turn, have shed light on their functional contribution to the epigenome for the first time. These initial investigations fired many additional questions, which remain to be explored. This review surveys the major results taken from these two new histone acylations and discusses the new biology that is emerging based on the diversity of histone lysine acylations.

  14. Defluoridation potential of jute fibers grafted with fatty acyl chain

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Suvendu; Saha, Prosenjit [Materials Science Centre, IIT Kharagpur, WB 721302 (India); Roy, Debasis, E-mail: debasis@civil.iitkgp.ernet.in [Department of Civil Engineering, IIT Kharagpur, WB 721302 (India); Sen, Ramkrishna [Department of Biotechnology, IIT Kharagpur, WB 721302 (India); Adhikari, Basudam [Materials Science Centre, IIT Kharagpur, WB 721302 (India)

    2015-11-30

    Graphical abstract: - Highlights: • Acyl chain grafted jute has been shown to accumulate fluoride ions. • Covalent and hydrogen bonding and protonation were the contributing factors. • The process is relatively inexpensive and maintenance-free. • Acyl chain grafted jute showed higher fluoride ions accumulation than alternatives. - Abstract: Waterborne fluoride is usually removed from water by coagulation, adsorption, ion exchange, electro dialysis or reverse osmosis. These processes are often effective over narrow pH ranges, release ions considered hazardous to human health or produce large volumes of toxic sludge that are difficult to handle and dispose. Although plant matters have been shown to remove waterborne fluoride, they suffer from poor removal efficiency. Following from the insight that interaction between microbial carbohydrate biopolymers and anionic surfaces is often facilitated by lipids, an attempt has been made to enhance fluoride adsorption efficiency of jute by grafting the lignocellulosic fiber with fatty acyl chains found in vegetable oils. Fluoride removal efficiency of grafted jute was found to be comparable or higher than those of alternative defluoridation processes. Infrared and X-ray photoelectron spectroscopic evidence indicated that hydrogen bonding, protonation and C−F bonding were responsible for fluoride accumulation on grafted jute. Adsorption based on grafted jute fibers appears to be an economical, sustainable and eco-friendly alternative technique for removing waterborne fluoride.

  15. Synthesis and biological activities of turkesterone 11?-acyl derivatives

    Directory of Open Access Journals (Sweden)

    Laurence Dinan

    2003-02-01

    Full Text Available Turkesterone is a phytoecdysteroid possessing an 11alpha-hydroxyl group. It is an analogue of the insect steroid hormone 20-hydroxyecdysone. Previous ecdysteroid QSAR and molecular modelling studies predicted that the cavity of the ligand-binding domain of the ecdysteroid receptor would possess space in the vicinity of C-11/C-12 of the ecdysteroid. We report the regioselective synthesis of a series of turkesterone 11alpha-acyl derivatives in order to explore this possibility. The structures of the analogues have been unambiguously determined by spectroscopic means (NMR and low-resolution mass spectrometry. Purity was verified by HPLC. Biological activities have been determined in Drosophila melanogaster BII cell-based bioassay for ecdysteroid agonists and in an in vitro radioligand-displacement assay using bacterially expressed D. melanogaster EcR/USP receptor proteins. The 11alpha-acyl derivatives do retain a significant amount of biological activity relative to the parent ecdysteroid. Further, although activity initially drops with the extension of the acyl chain length (C2 to C4, it then increases (C6 to C10, before decreasing again (C14 and C20. The implications of these findings for the interaction of ecdysteroids with the ecdysteroid receptor and potential applications in the generation of affinity-labelled and fluorescently-tagged ecdysteroids are discussed.

  16. Acyl chain length of phosphatidylserine is correlated with plant lifespan.

    Directory of Open Access Journals (Sweden)

    Yan Li

    Full Text Available Plant lifespan is affected by factors with genetic and environmental bases. The laws governing these two factors and how they affect plant lifespan are unclear. Here we show that the acyl chain length (ACL of phosphatidylserine (PS is correlated with plant lifespan. Among the detected eight head-group classes of membrane lipids with lipidomics based on triple quadrupole tandem mass spectrometry, the ACL of PS showed high diversity, in contrast to the ACLs of the other seven classes, which were highly conserved over all stages of development in all plant species and organs and under all conditions that we studied. Further investigation found that acyl chains of PS lengthened during development, senescence, and under environmental stresses and that increasing length was accelerated by promoted- senescence. The acyl chains of PS were limited to a certain carbon number and ceased to increase in length when plants were close to death. These findings suggest that the ACL of PS can count plant lifespan and could be a molecular scale ruler for measuring plant development and senescence.

  17. Acyl chain length of phosphatidylserine is correlated with plant lifespan.

    Science.gov (United States)

    Li, Yan; Zheng, Guowei; Jia, Yanxia; Yu, Xiaomei; Zhang, Xudong; Yu, Buzhu; Wang, Dandan; Zheng, Yanling; Tian, Xuejun; Li, Weiqi

    2014-01-01

    Plant lifespan is affected by factors with genetic and environmental bases. The laws governing these two factors and how they affect plant lifespan are unclear. Here we show that the acyl chain length (ACL) of phosphatidylserine (PS) is correlated with plant lifespan. Among the detected eight head-group classes of membrane lipids with lipidomics based on triple quadrupole tandem mass spectrometry, the ACL of PS showed high diversity, in contrast to the ACLs of the other seven classes, which were highly conserved over all stages of development in all plant species and organs and under all conditions that we studied. Further investigation found that acyl chains of PS lengthened during development, senescence, and under environmental stresses and that increasing length was accelerated by promoted- senescence. The acyl chains of PS were limited to a certain carbon number and ceased to increase in length when plants were close to death. These findings suggest that the ACL of PS can count plant lifespan and could be a molecular scale ruler for measuring plant development and senescence.

  18. Phylogenetic and experimental characterization of an acyl-ACP thioesterase family reveals significant diversity in enzymatic specificity and activity

    Directory of Open Access Journals (Sweden)

    Yandeau-Nelson Marna D

    2011-08-01

    Full Text Available Abstract Background Acyl-acyl carrier protein thioesterases (acyl-ACP TEs catalyze the hydrolysis of the thioester bond that links the acyl chain to the sulfhydryl group of the phosphopantetheine prosthetic group of ACP. This reaction terminates acyl chain elongation of fatty acid biosynthesis, and in plant seeds it is the biochemical determinant of the fatty acid compositions of storage lipids. Results To explore acyl-ACP TE diversity and to identify novel acyl ACP-TEs, 31 acyl-ACP TEs from wide-ranging phylogenetic sources were characterized to ascertain their in vivo activities and substrate specificities. These acyl-ACP TEs were chosen by two different approaches: 1 24 TEs were selected from public databases on the basis of phylogenetic analysis and fatty acid profile knowledge of their source organisms; and 2 seven TEs were molecularly cloned from oil palm (Elaeis guineensis, coconut (Cocos nucifera and Cuphea viscosissima, organisms that produce medium-chain and short-chain fatty acids in their seeds. The in vivo substrate specificities of the acyl-ACP TEs were determined in E. coli. Based on their specificities, these enzymes were clustered into three classes: 1 Class I acyl-ACP TEs act primarily on 14- and 16-carbon acyl-ACP substrates; 2 Class II acyl-ACP TEs have broad substrate specificities, with major activities toward 8- and 14-carbon acyl-ACP substrates; and 3 Class III acyl-ACP TEs act predominantly on 8-carbon acyl-ACPs. Several novel acyl-ACP TEs act on short-chain and unsaturated acyl-ACP or 3-ketoacyl-ACP substrates, indicating the diversity of enzymatic specificity in this enzyme family. Conclusion These acyl-ACP TEs can potentially be used to diversify the fatty acid biosynthesis pathway to produce novel fatty acids.

  19. [Fungistatic activity of a sesquiterpene lactone (tomentosin) isolated from fresh Inula viscosa (Asteraceae) flowers from the Puglia region].

    Science.gov (United States)

    Cafarchia, C; De Laurentis, N; Milillo, M A; Losacco, V; Puccini, V

    2001-09-01

    A sesquiterpene lactone, tomentosin, has been isolated and identified form Inula viscosá Ait (Asteraceae) flowers. The molecule, at 1 mg/ml concentration, showed to be active in vitro against Microsporum canis, Microsporum gypseum and Trichophyton mentagrophytes.

  20. 9-Hydroxyfurodysinin-O-ethyl Lactone: A New Sesquiterpene Isolated from the Tropical Marine Sponge Dysidea arenaria

    Directory of Open Access Journals (Sweden)

    P. Karuso

    2005-10-01

    Full Text Available A new sesquiterpene, 9-hydroxyfurodysinin-O-ethyl lactone, has been isolated from a New Caledonian Dysidea arenaria, along with three known compounds. The possible incorporation of the ethyl ether from the extraction solvent is discussed.

  1. Effects of α,β-unsaturated lactones on larval survival and gut trypsin as well as oviposition response of Aedes aegypti.

    Science.gov (United States)

    Barros, Maria Ester S B; Freitas, Juliano C R; Santos, Geanne K N; da Silva, Rayane Cristine Santos; Pontual, Emmanuel V; Paiva, Patrícia M G; Napoleão, Thiago H; Navarro, Daniela M A F; Menezes, Paulo H

    2015-09-01

    Lactones are organic cyclic esters that have been described as larvicides against Aedes aegypti and as components of oviposition pheromone of Culex quinquefasciatus. This work describes the effect of six α,β-unsaturated lactones (5a-5f) on survival of A. aegypti fourth instar larvae (L4). It is also reported the effects of the lactones on L4 gut trypsin activity and oviposition behavior of A. aegypti females. Five lactones were able to kill L4 being the lactones 5a (LC50 of 39.05 ppm), 5e (LC50 of 36.30 ppm) and 5f (LC50 of 40.46 ppm) the most promising larvicides. Only the lactone 5a inhibited L4 gut trypsin activity, with an IC50 of 115.15 µg/mL. Lactones 5a, 5c, 5d and 5e did not exert deterrent or stimulatory effects on oviposition, whereas lactone 5b exhibited a strong deterrent oviposition activity. In conclusion, this work introduces new α,β-unsaturated lactones as promising alternatives to control A. aegypti dissemination. The larvicidal mechanism of the lactone 5a can involve the disruption of proteolysis at larval gut.

  2. Accumulation of Glycoconjugates of 3-Methyl-4-hydroxyoctanoic Acid in Fruits, Leaves, and Shoots of Vitis vinifera cv. Monastrell following Foliar Applications of Oak Extract or Oak Lactone.

    Science.gov (United States)

    Pardo-Garcia, Ana I; Wilkinson, Kerry L; Culbert, Julie A; Lloyd, Natoiya D R; Alonso, Gonzalo L; Salinas, M Rosario

    2015-05-13

    Grapevines are capable of absorbing volatile compounds present in the vineyard during the growing season, and in some cases, volatiles have been found to accumulate in fruits or leaves in glycoconjugate forms, that is, with one or more sugar moieties attached. The presence of oak lactone in wine is usually attributable to oak maturation, but oak lactone has been detected in wines made with fruit from grapevines treated with oak extract or oak lactone. This study investigated the accumulation of glycoconjugates of 3-methyl-4-hydroxyoctanoic acid (i.e., the ring-opened form of oak lactone) in the fruits, leaves, and shoots of Monastrell grapevines following foliar application of either oak extract or oak lactone at approximately 7 days postveraison. Fruits, leaves, and shoots were collected at three different time points, including at maturity. The oak lactone content of fruit was determined by gas chromatography-mass spectrometry, with declining concentrations observed in fruit from grapevines treated with oak lactone with ripening. The concentrations of a β-d-glucopyranoside of 3-methyl-4-hydroxyoctanoic acid in fruits, leaves, and shoots was determined by liquid chromatography-tandem mass spectrometry, with the highest oak lactone glucoside levels observed in leaves of grapevines treated with oak lactone. A glucose-glucose disaccharide was also tentatively identified. These results demonstrate both ring-opening and glycosylation of oak lactone occurred after experimental treatments were imposed.

  3. Conversion of the Vibrio fischeri Transcriptional Activator, LuxR, to a Repressor

    OpenAIRE

    Egland, Kristi A.; Greenberg, E. P.

    2000-01-01

    The Vibrio fischeri luminescence (lux) operon is regulated by a quorum-sensing system that involves the transcriptional activator (LuxR) and an acyl-homoserine lactone signal. Transcriptional activation requires the presence of a 20-base inverted repeat termed the lux box at a position centered 42.5 bases upstream of the transcriptional start of the lux operon. LuxR has proven difficult to study in vitro. A truncated form of LuxR has been purified, and together with ς70 RNA polymerase it can ...

  4. The enzymes of bacterial census and censorship.

    Science.gov (United States)

    Fast, Walter; Tipton, Peter A

    2012-01-01

    N-Acyl-L-homoserine lactones (AHLs) are a major class of quorum-sensing signals used by Gram-negative bacteria to regulate gene expression in a population-dependent manner, thereby enabling group behavior. Enzymes capable of generating and catabolizing AHL signals are of significant interest for the study of microbial ecology and quorum-sensing pathways, for understanding the systems that bacteria have evolved to interact with small-molecule signals, and for their possible use in therapeutic and industrial applications. The recent structural and functional studies reviewed here provide a detailed insight into the chemistry and enzymology of bacterial communication.

  5. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, Kathrin; Rasmussen, Thomas B;

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR by expression of an unstable version of the green-fluorescent protein (Gfp...... macroalga Delisea pulchra, is capable of interfering with AHL-mediated quorum sensing in P. aeruginosa. It is demonstrated that the furanone compound specifically represses expression of a PlasB-gfp reporter fusion without affecting growth or protein synthesis. In addition, it reduces the production...

  6. Quantum Nanobiology and Biophysical Chemistry

    DEFF Research Database (Denmark)

    2013-01-01

    An introduction was provided in the first issue by way of an Editorial to this special two issue volume of Current Physical Chemistry – “Quantum Nanobiology and Biophysical Chemistry” [1]. The Guest Editors would like to thank all the authors and referees who have contributed to this second issue....... demonstrate extremely low detection performance of acyl-homoserine lactone in a biologically relevant system using surface enhanced Raman spectroscopy. Sugihara and Bondar evaluate the influence of methyl-groups and the protein environment on retinal geometries in rhodopsin and bacteriorhodopsin, two...

  7. Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound

    DEFF Research Database (Denmark)

    Hentzer, Morten; Riedel, K.; Rasmussen, Thomas Bovbjerg

    2002-01-01

    Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR lay expression of an unstable version of the green-fluorescent protein (Gfp......). Gfp-based reporter technology has been applied for non-destructive, single-cell-level detection of quorum sensing in laboratory-based P. aeruginosa biofilms. It is reported that a synthetic halogenated furanone compound, which is a derivative of the secondary metabolites produced by the Australian...

  8. Quorum sensing Inhibitors as anti-pathogenic drugs

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bovbjerg; Givskov, Michael Christian

    2006-01-01

    as well as elevated tolerance to the activity of the innate immune system. Gram-negative bacteria commonly use N-acyl homoserine lactones (AHL) as QS signal molecules. The use of signal molecule based drugs to attenuate bacterial pathogenecity rather than bacterial growth is attractive for several reasons......, particularly considering the emergence of increasingly antibiotic-resistant bacteria. Compounds capable of this type of interference have been termed anti-pathogenic drugs. A large variety of synthetic AHL analogues and natural products libraries have been screened and a number of QS inhibitors (QSI) have been...

  9. Protoanemonin

    DEFF Research Database (Denmark)

    Bobadilla Fazzini, Roberto A; Skindersoe, Mette E; Bielecki, Piotr

    2013-01-01

    Many Gram-negative bacteria employ cell-to-cell communication mediated by N-acyl homoserine lactones (quorum sensing) to control expression of a wide range of genes including, but not limited to, genes encoding virulence factors. Outside the laboratory, the bacteria live in complex communities...... where signals may be perceived across species. We here present a newly found natural quorum sensing inhibitor, produced by the pseudomonads Pseudomonas sp. B13 and Pseudomonas reinekei MT1 as a blind end in the biodegradation of organochloride xenobiotics, which inhibits quorum sensing in P. aeruginosa...

  10. Characterization of Lipid A Variants by Energy-Resolved Mass Spectrometry: Impact of Acyl Chains

    Science.gov (United States)

    Crittenden, Christopher M.; Akin, Lucas D.; Morrison, Lindsay J.; Trent, M. Stephen; Brodbelt, Jennifer S.

    2016-12-01

    Lipid A molecules consist of a diglucosamine sugar core with a number of appended acyl chains that vary in their length and connectivity. Because of the challenging nature of characterizing these molecules and differentiating between isomeric species, an energy-resolved MS/MS strategy was undertaken to track the fragmentation trends and map genealogies of product ions originating from consecutive cleavages of acyl chains. Generalizations were developed based on the number and locations of the primary and secondary acyl chains as well as variations in preferential cleavages arising from the location of the phosphate groups. Secondary acyl chain cleavage occurs most readily for lipid A species at the 3' position, followed by primary acyl chain fragmentation at both the 3' and 3 positions. In the instances of bisphosphorylated lipid A variants, phosphate loss occurs readily in conjunction with the most favorable primary and secondary acyl chain cleavages.

  11. Polymerization of 5-alkyl δ-lactones catalyzed by diphenyl phosphate and their sequential organocatalytic polymerization with monosubstituted epoxides

    KAUST Repository

    Zhao, Junpeng

    2015-02-04

    Organocatalytic ring-opening polymerization (ROP) reactions of three renewable 5-alkyl δ-lactones, namely δ-hexalactone (HL), δ-nonalactone (NL) and δ-decalactone (DL), using diphenyl phosphate (DPP) were investigated. Room temperature, together with a relatively high monomer concentration (≥3 M), was demonstrated to be suitable for achieving a living ROP behavior, a high conversion of the lactone, a controlled molecular weight and a low dispersity of the polyester. HL, containing a 5-methyl substituent, showed a much higher reactivity (polymerization rate) and a slightly higher equilibrium conversion than the compounds with longer alkyl substituents (NL and DL). The effectiveness of DPP-catalyzed ROP of 5-alkyl δ-lactones facilitated the one-pot performance following the t-BuP4-promoted ROP of monosubstituted epoxides. It has been shown in an earlier study that substituted polyethers acted as "slow initiators" for non-substituted lactones. However, efficient initiations were observed in the present study as substituted lactones were polymerized from the substituted polyethers. Therefore, this reinforces the previously developed "catalyst switch" strategy, making it a more versatile tool for the synthesis of well-defined polyether-polyester block copolymers from a large variety of epoxide and lactone monomers. © The Royal Society of Chemistry 2015.

  12. 23(S),25(R)-1,25-dihydroxyvitamin D3-26,23-lactone stimulates murine bone formation in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Shima, M.; Tanaka, H.; Norman, A.W.; Yamaoka, K.; Yoshikawa, H.; Takaoka, K.; Ishizuka, S.; Seino, Y. (Osaka Univ. School of Medicine (Japan))

    1990-02-01

    23(S),25(R)-1,25-Dihydroxyvitamin D3-26,23-lactone (1,25-lactone) has been shown to have unique actions different from those of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). In contrast to 1,25-(OH)2D3, 1,25-lactone causes a significant reduction in the serum Ca2+ level, stimulates collagen production in an osteoblastic cell line, and inhibits bone resorption induced by 1,25-(OH)2D3. A possible effect of 1,25-lactone on bone formation was examined in experiments on ectopic bone formation using a bone-inducing factor derived from Dunn osteosarcomas. 1,25-Lactone, a metabolite of 1,25-(OH)2D3, increased (3H)proline uptake at the stage of chondrogenesis and {sup 85}Sr uptake during bone formation. Significantly enlarged bone was also induced by this compound 3 weeks after implantation. These results suggest that the 1,25-lactone may be able to stimulate bone formation under in vivo conditions.

  13. Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Li, Conghu [The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065 (China); College of Life Sciences, Anqing Normal University, Anqing 246011 (China); Tian, Zhenhua; Liu, Wentao [The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065 (China); Li, Guoying, E-mail: liguoyings@163.com [The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065 (China)

    2015-10-01

    The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen. - Highlights: • Acylated collagen retained the unique triple helix conformation. • Acylated collagen had stronger thermostability than native collagen. • Amide I was the most sensitive band to the temperature for acylated collagen. • Amide II was the most sensitive band to the temperature for native collagen. • Auto-peak at 1680 cm{sup −1} for acylated collagen disappeared at higher temperature.

  14. Production of structured lipids: acyl migration during enzymatic interesterification and downstream processing

    DEFF Research Database (Denmark)

    Xu, Xuebing

    1997-01-01

    -2 position or sn-1,3 positions of glycerol backbone. These kinds of lipids are reported to be promising for both enteral and parenteral nutrition. However, acyl migration occurs in the reaction stage and downstream purification process. This side-reaction causes by-products which are harmful...... to the required products. In this paper, the reasons of acyl migration and factors affecting the acyl migration were reviewed and discussed. The possible solutions were also evaluated....

  15. 2-Bromopalmitate Reduces Protein Deacylation by Inhibition of Acyl-Protein Thioesterase Enzymatic Activities

    OpenAIRE

    Pedro, Maria P.; Vilcaes, Aldo A.; Vanesa M Tomatis; Oliveira, Rafael G.; Gomez, Guillermo A; Daniotti, Jose L.

    2013-01-01

    S-acylation, the covalent attachment of palmitate and other fatty acids on cysteine residues, is a reversible post-translational modification that exerts diverse effects on protein functions. S-acylation is catalyzed by protein acyltransferases (PAT), while deacylation requires acyl-protein thioesterases (APT), with numerous inhibitors for these enzymes having already been developed and characterized. Among these inhibitors, the palmitate analog 2-brompalmitate (2-BP) is the most commonly use...

  16. A rapid and specific derivatization procedure to identify acyl-glucuronides by mass spectrometry.

    Science.gov (United States)

    Vaz, Alfin D N; Wang, Wei Wei; Bessire, Andrew J; Sharma, Raman; Hagen, Anne E

    2010-07-30

    A simple procedure is described to identify acyl-glucuronides by coupled liquid chromatography/mass spectrometry after derivatization to a hydroxamic acid with hydroxylamine. The reaction specificity obviates the need for isolation of the acyl-glucuronide from an extract. Glucuronides derived from carbamic acids, and alkyl- and aromatic amines, are inert to the derivatization reaction conditions, making the hydroxamic acid derivative a fingerprint for acyl-glucuronides.

  17. Cascade Synthesis of Five-Membered Lactones using Biomass-Derived Sugars as Carbon Nucleophiles.

    Science.gov (United States)

    Yamaguchi, Sho; Matsuo, Takeaki; Motokura, Ken; Miyaji, Akimitsu; Baba, Toshihide

    2016-06-06

    We report the cascade synthesis of five-membered lactones from a biomass-derived triose sugar, 1,3-dihydroxyacetone, and various aldehydes. This achievement provides a new synthetic strategy to generate a wide range of valuable compounds from a single biomass-derived sugar. Among several examined Lewis acid catalysts, homogeneous tin chloride catalysts exhibited the best performance to form carbon-carbon bonds. The scope and limitations of the synthesis of five-membered lactones using aldehyde compounds are investigated. The cascade reaction led to high product selectivity as well as diastereoselectivity, and the mechanism leading to the diastereoselectivity was discussed based on isomerization experiments and density functional theory (DFT) calculations. The present results are expected to support new approaches for the efficient utilization of biomass-derived sugars.

  18. Kinase inhibition by deoxy analogues of the resorcylic lactone L-783277.

    Science.gov (United States)

    Liniger, Marc; Neuhaus, Christian; Hofmann, Tatjana; Fransioli-Ignazio, Luca; Jordi, Michel; Drueckes, Peter; Trappe, Jörg; Fabbro, Doriano; Altmann, Karl-Heinz

    2011-01-13

    The natural product L-783277 is a resorcylic lactone type covalent kinase inhibitor. We have prepared the 5'-deoxy analogue of L-783277 (1) in a stereoselective fashion. Remarkably, this analogue retains almost the full kinase inhibitory potential of natural L-783277, with low nanomolar IC50 values against the most sensitive kinases, and it exhibits essentially the same selectivity profile (within the panel of 39 kinases investigated). In contrast, removal of both the 4'- and the 5'-hydroxyl groups leads to a more significant reduction in kinase inhibitory activity and so does a change in the geometry of the C7'-C8' double bond in 1 from Z to E. These findings offer new perspectives for the design of second generation resorcylic lactone-based kinase inhibitors.

  19. Method to produce water-soluble sugars from biomass using solvents containing lactones

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A.; Luterbacher, Jeremy S.

    2015-06-02

    A process to produce an aqueous solution of carbohydrates that contains C6-sugar-containing oligomers, C6 sugar monomers, C5-sugar-containing oligomers, C5 sugar monomers, or any combination thereof is presented. The process includes the steps of reacting biomass or a biomass-derived reactant with a solvent system including a lactone and water, and an acid catalyst. The reaction yields a product mixture containing water-soluble C6-sugar-containing oligomers, C6-sugar monomers, C5-sugar-containing oligomers, C5-sugar monomers, or any combination thereof. A solute is added to the product mixture to cause partitioning of the product mixture into an aqueous layer containing the carbohydrates and a substantially immiscible organic layer containing the lactone.

  20. Covalent Modification of Human Serum Albumin by the Natural Sesquiterpene Lactone Parthenolide

    Directory of Open Access Journals (Sweden)

    Michael Plöger

    2015-04-01

    Full Text Available The reactivity of parthenolide (PRT, a natural sesquiterpene lactone from Tanacetum parthenium (Asteraceae, with human serum albumin (HSA was studied by UHPLC/+ESI-QqTOF MS analysis after tryptic digestion of albumin samples after incubation with this compound. It was found that the single free cysteine residue, C34, of HSA (0.6 mM reacted readily with PRT when incubated at approximately 13-fold excess of PRT (8 mM. Time-course studies with PRT and its 11β,13-dihydro derivative at equimolar ratios of the reactants revealed that PRT under the chosen conditions reacts preferably with C34 and does so exclusively via its α-methylene-γ-lactone moiety, while the epoxide structure is not involved in the reaction.

  1. Covalent modification of human serum albumin by the natural sesquiterpene lactone parthenolide.

    Science.gov (United States)

    Plöger, Michael; Sendker, Jandirk; Langer, Klaus; Schmidt, Thomas J

    2015-04-09

    The reactivity of parthenolide (PRT), a natural sesquiterpene lactone from Tanacetum parthenium (Asteraceae), with human serum albumin (HSA) was studied by UHPLC/+ESI-QqTOF MS analysis after tryptic digestion of albumin samples after incubation with this compound. It was found that the single free cysteine residue, C34, of HSA (0.6 mM) reacted readily with PRT when incubated at approximately 13-fold excess of PRT (8 mM). Time-course studies with PRT and its 11β,13-dihydro derivative at equimolar ratios of the reactants revealed that PRT under the chosen conditions reacts preferably with C34 and does so exclusively via its α-methylene-γ-lactone moiety, while the epoxide structure is not involved in the reaction.

  2. Method to produce water-soluble sugars from biomass using solvents containing lactones

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A.; Luterbacher, Jeremy S.

    2017-08-08

    A process to produce an aqueous solution of carbohydrates that contains C6-sugar-containing oligomers, C6 sugar monomers, C5-sugar-containing oligomers, C5 sugar monomers, or any combination thereof is presented. The process includes the steps of reacting biomass or a biomass-derived reactant with a solvent system including a lactone and water, and an acid catalyst. The reaction yields a product mixture containing water-soluble C6-sugar-containing oligomers, C6-sugar monomers, C5-sugar-containing oligomers, C5-sugar monomers, or any combination thereof. A solute is added to the product mixture to cause partitioning of the product mixture into an aqueous layer containing the carbohydrates and a substantially immiscible organic layer containing the lactone.

  3. Method to produce water-soluble sugars from biomass using solvents containing lactones

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A.; Luterbacher, Jeremy S.

    2015-06-02

    A process to produce an aqueous solution of carbohydrates that contains C6-sugar-containing oligomers, C6 sugar monomers, C5-sugar-containing oligomers, C5 sugar monomers, or any combination thereof is presented. The process includes the steps of reacting biomass or a biomass-derived reactant with a solvent system including a lactone and water, and an acid catalyst. The reaction yields a product mixture containing water-soluble C6-sugar-containing oligomers, C6-sugar monomers, C5-sugar-containing oligomers, C5-sugar monomers, or any combination thereof. A solute is added to the product mixture to cause partitioning of the product mixture into an aqueous layer containing the carbohydrates and a substantially immiscible organic layer containing the lactone.

  4. Steroidal Lactones from Withania somnifera, an Ancient Plant for Novel Medicine

    Directory of Open Access Journals (Sweden)

    Javier Palazón

    2009-07-01

    Full Text Available Withania somnifera, commonly known as Ashwagandha, is an important medicinal plant that has been used in Ayurvedic and indigenous medicine for over 3,000 years. In view of its varied therapeutic potential, it has also been the subject of considerable modern scientific attention. The major chemical constituents of the Withania genus, the withanolides, are a group of naturally occurring C28-steroidal lactone triterpenoids built on an intact or rearranged ergostane framework, in which C-22 and C-26 are appropriately oxidized to form a six-membered lactone ring. In recent years, numerous pharmacological investigations have been carried out into the components of W. somnifera extracts. We present here an overview of the chemical structures of triterpenoid components and their biological activity, focusing on two novel activities, tumor inhibition and antiangiogenic properties of withaferin A and the effects of withanolide A on Alzheimer's disease. The most recent attempts in biotechnological production of withanolides are also discussed.

  5. Development of Acid Functional Groups and Lactones During the Thermal Degradation of Wood and Wood Components

    Science.gov (United States)

    Rutherford, David W.; Wershaw, Robert L.; Reeves, James B.

    2008-01-01

    Black carbon (pyrogenic materials including chars) in soils has been recognized as a substantial portion of soil organic matter, and has been shown to play a vital role in nutrient cycling; however, little is known concerning the properties of this material. Previous studies have largely been concerned with the creation of high-surface-area materials for use as sorbents. These materials have been manufactured at high temperature and have often been activated. Chars occurring in the environment can be formed over a wide range of temperature. Because it is extremely difficult to isolate black carbon once it has been incorporated in soils, chars produced in the laboratory under controlled conditions can be used to investigate the range of properties possible for natural chars. This report shows that charring conditions (temperature and time) have substantial impact on the acid functional group and lactone content of chars. Low temperatures (250?C) and long charring times (greater than 72 hours) produce chars with the highest acid functional group and lactone content. The charring of cellulose appears to be responsible for the creation of the acid functional group and lactones. The significance of this study is that low-temperature chars can have acid functional group contents comparable to humic materials (as high as 8.8 milliequivalents per gram). Acid functional group and lactone content decreases as charring temperature increases. The variation in formation conditions expected under natural fire conditions will result in a wide range of sorption properties for natural chars which are an important component of soil organic matter. By controlling the temperature and duration of charring, it is possible to tailor the sorption properties of chars, which may be used as soil amendments.

  6. Design of Countercurrent Separation of Ginkgo biloba Terpene Lactones by Nuclear Magnetic Resonance

    Science.gov (United States)

    Qiu, Feng; Friesen, Brent J.; McAlpine, James B.; Pauli, Guido F.

    2012-01-01

    Terpene lactones such as bilobalide, ginkgolides A, B, C, and J are major bioactive compounds of Ginkgo biloba L. Purification of these compounds is tedious due to their similar chemical properties. For the purpose of developing an effective and efficient method for both analytical and preparative separation of terpene lactones in G. biloba, an innovative orthogonality-enhanced high-speed countercurrent chromatography (HSCCC) method was established. Taking advantage of quantitative 1H NMR (qHNMR) methodology, partition coefficients (K) of individual terpene lactones were calculated directly from crude G. biloba leaf extract, using their H-12 signals as distinguishing feature. The partitioning experiment assisted the design of a two dimensional (2D) HSCCC procedure using a pair of orthogonal HSCCC solvent systems (SSs), ChMWat +4 and HEMSoWat +3/0.05%. It was surprising that the resolution of ginkgolides A and B was improved by 25% in the HEMWat +3 SS modified with 0.5% DMSO. Consequently, all five terpene lactones could be well separated with qHNMR purity > 95% from G. biloba leaf extract. The separation was further evaluated by offline qHNMR analysis of HSCCC fractions associated with Gaussian curve fitting. The results showed less than 2% error in HSCCC retention predicted from the partitioning experiment. This compelling consistency demonstrates that qHNMR-derived K determination (“K-by-NMR”) can be used to predict CCC fractionation and target purification of analytes from complex mixtures. Furthermore, Gaussian curve fitting enabled an accurate prediction of less than 2% impurity in the CCC fraction, which demonstrates its potential as a powerful tool to study the presence of minor constituents, especially when they are beyond the detection limit of conventional spectroscopic detectors. PMID:22579361

  7. Two lactones in the androconial scent of the lycaenid butterfly Celastrina argiolus ladonides

    Science.gov (United States)

    Ômura, Hisashi; Yakumaru, Kazuhisa; Honda, Keiichi; Itoh, Takao

    2013-04-01

    Male adult butterflies of many species have characteristic odors originating from the disseminating organs known as androconia. Despite the fact that androconia exist in several species, there have been few investigations on adult scents from the lycaenid species. Celastrina argiolus ladonides (Lycaenidae) is a common species in Eurasia. We have reported that male adults of this species emit a faint odor, and the major components causing this odor have been newly found in the Insecta. By using field-caught individuals, we determined the chemical nature and location of this odor in the butterfly. Gas chromatography-mass spectrometry (GC-MS) analyses revealed that two lactone compounds, lavender lactone and δ-decalactone, are present in the extracts of males but absent in those of the females. On an average, approximately 50 ng of each compound was found per male. Chiral GC analyses performed using enantiomerically pure standards revealed that the natural lavender lactone was a mixture of two enantiomers with an R/ S ratio of 32:68, whereas the natural δ-decalactone contained only the R-enantiomer. When the analyses were conducted using different parts—forewings, hindwings, and body—of three males, the lactones were more abundantly found on the forewings and hindwings than on the body. Microscopic observation of the wings demonstrated that battledore scales known as androconia are scattered on the upper surface of both the wings of C. argiolus ladonides males. These results indicate that the specialized scales on the wings of males serve as scent-disseminating organs.

  8. Sesquiterpene lactones. XXXIII. Guaianolides in the subgenus Psephellus (Cass.) Schmalh., genus Centaurea L.

    OpenAIRE

    Gerard Nowak; Bohdan Drożdż; Miroslav Holub; Agnieszka Łagodzińska

    2014-01-01

    Sesquiterpene lactones were found to occur in all of the studied species of the subgenus Psephellus (Cass.) Schmalh. Differing compositions were found in the representatives of three sections. In Centaurea declinata MB. from the section Leucophylle (Sosn.) Sosn.. 15-deoxyrepin, linichlorin B and cynaropicrin were found. Linichlorin B dominated in Centaurea hypoleucu DC. from section Hypoleucae (Sosn.) Sosn., while in the species classified in section Psephellus Sosn., repin, acroptilin, jener...

  9. Sesquiterpene lactones. XXXIII. Guaianolides in the subgenus Psephellus (Cass. Schmalh., genus Centaurea L.

    Directory of Open Access Journals (Sweden)

    Gerard Nowak

    2014-01-01

    Full Text Available Sesquiterpene lactones were found to occur in all of the studied species of the subgenus Psephellus (Cass. Schmalh. Differing compositions were found in the representatives of three sections. In Centaurea declinata MB. from the section Leucophylle (Sosn. Sosn.. 15-deoxyrepin, linichlorin B and cynaropicrin were found. Linichlorin B dominated in Centaurea hypoleucu DC. from section Hypoleucae (Sosn. Sosn., while in the species classified in section Psephellus Sosn., repin, acroptilin, jenerin, centaurepensin and, in some, also cynaropicrin. dominated.

  10. Sesquiterpene lactones. XXXII. Guaianolides in species from the genus Chartolepis Cass.

    OpenAIRE

    Gerard Nowak; Bohdan Drożdż; Miroslav Holub

    2014-01-01

    Differences in the composition of the "lactone fraction" of 4 species from the genus Chartolepis Cass. were observed. Cynaropierin was isolated from the above-ground parts of Chartolepis intermedia Boiss. and the occurrence there of grossheimin was confirmed. The following compounds were isolated from the above-ground parts of Chartolepis glastifolia (L.) Cass.: centaurepensin, repin, cebellin C, acroptillin, cebellin D, cynaropicrin, cebellin F and janerin. Centaurepensin, repin, cebellin C,...

  11. Bacillus marcorestinctum sp. nov., a Novel Soil Acylhomoserine Lactone Quorum-Sensing Signal Quenching Bacterium

    OpenAIRE

    Xianzhen Li; Bo Zhu; Nuo Li; Fang Chen; Yan Han

    2010-01-01

    A Gram-positive, facultatively anaerobic, endospore-forming and rod-shaped bacterium was isolated from soil samples and designated strain LQQ. This organism strongly quenches the acylhomoserine lactone quorum-sensing signal. The LQQ strain exhibits phenotypic characteristics consistent with its classification in the genus Bacillus. It is positive in catalase and no special growth factor is needed. It uses glucose as sole carbon source. The DNA G + C content is 39.8 mol %. The closest relative...

  12. Characterization of the Acyl-Adenylate Linked Metabolite of Mefenamic Acid

    OpenAIRE

    2013-01-01

    Mefenamic acid, (MFA), a carboxylic acid-containing nonsteroidal anti-inflammatory drug (NSAID), is metabolized into the chemically-reactive conjugates MFA-1-O-acyl-glucuronide (MFA-1-O-G) and MFA-S-acyl-CoA (MFA-CoA), which are both implicated in the formation of MFA-S-acyl-glutathione (MFA-GSH) conjugates, protein-adduct formation and thus the potential toxicity of the drug. However, current studies suggest that an additional acyl-linked metabolite may be implicated in the formation of MFA-...

  13. Antimicrobial activities of isoalantolactone,a major sesquiterpene lactone of Inula racemosa

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Isoalantolactone,a major constituent of Inula racemosa (Compositae) was tested for its antimicrobial action against five bacteria,six human and six plant pathogenic fungi. The lactone showed absolute toxicities at 500 mg/mL against 3 soil borne phytopathogenic fungi (Gaeumannomyces graminis var. tritici,Rhizoctonia cerealis and Phytophthora capsici) with the MICs determined to be 100,100 and 300 mg/mL,respectively. At the MICs,isoalantolactone exhibited its fungistatic nature of toxicity. The lowest fungicidal concentrations of the lactone to G. graminis var. tritici,R. cerealis and P. capsici were shown to be 150,150 and 350 mg/mL,respectively. Moreover,isoalantolactone displayed weaker antibacterial activities against Bacillus subtilis,Escherichia coli,Pseudomonas fluorecense,Sarcina lentus and Staphylococcus aureus with MICs of 125,425,150,150 and 100 mg/mL,respectively. The investigation disclosed the strong inhibition of isoalantolactone to the phytopathogenic fungi,raising a possibility that the lactone could be considered as a starting point for the project aiming at the development of new fungicide(s).

  14. Potent Antifouling Resorcylic Acid Lactones from the Gorgonian-Derived Fungus Cochliobolus lunatus

    KAUST Repository

    Shao, Chang Lun

    2011-04-25

    Three new 14-membered resorcylic acid lactones, two with a rare natural acetonide group and one with a 5-chloro-substituted lactone, named cochliomycins A-C (1-3), together with four known analogues, zeaenol (4), LL-Z1640-1 (5), LL-Z1640-2 (6), and paecilomycin F (7), were isolated from the culture broth of Cochliobolus lunatus, a fungus obtained from the gorgonian Dichotella gemmacea collected in the South China Sea. Their structures and the relative configurations of 1-3 were elucidated using comprehensive spectroscopic methods including NOESY spectra and chemical conversions. A transetherification reaction was also observed in which cochliomycin B (2) in a solution of CDCl3 slowly rearranged to give cochliomycin A (1) at room temperature. These resorcylic acid lactones were evaluated against the larval settlement of barnacle Balanus amphitrite, and antifouling activity was detected for the first time for this class of metabolites. The antibacterial and cytotoxic activities of these compounds were also examined. © 2011 The American Chemical Society and American Society of Pharmacognosy.

  15. History of avermectin and ivermectin, with notes on the history of other macrocyclic lactone antiparasitic agents.

    Science.gov (United States)

    Campbell, William C

    2012-05-01

    The macrocyclic lactones enjoy a position of prominence in the control of parasites, and their history may be of interest, and even of use, in an age in which the search for chemotherapeutic agents has been transformed by modern technology. Much of their history has been recorded piecemeal in a wide variety of publications. The present review provides additional detail, and offers a personal perspective on the history of ivermectin and related avermectins. Brief notes are included on the subsequent development of other macrocyclic lactones. Milbemycin preceded the avermectins as a macrocyclic lactone of agricultural importance, but was used for a different purpose. Development of the avermectins arose from the isolation, in the laboratories of the Kitasato Institute, of a novel soil-dwelling bacterium and its transmittal (in 1974) to the laboratories of Merck & Co., Inc. There it was found (in 1975) to produce a potent anthelmintic substance, which was then identified and transmuted by interdisciplinary research into an antiparasitic product. Initially the focus was on its applicability to veterinary science and animal husbandry; and after developmental research by many scientific teams, the product was introduced commercially (in 1981) for the control of endoparasitic nematodes and ectoparasitic arthropods in livestock. Subsequently, special applications in human medicine were developed, and were successfully implemented in partnership with World Health Organization and several non-governmental organizations (NGOs).

  16. Heartworms, macrocyclic lactones, and the specter of resistance to prevention in the United States

    Directory of Open Access Journals (Sweden)

    Bowman Dwight D

    2012-07-01

    Full Text Available Abstract In order to provide a background to current concerns relative to the possible resistance of heartworms to macrocyclic lactones, this review summarizes various studies in which lack of efficacies (LOEs have been observed in dogs on macrocyclic lactone preventives relative to the United States of America. Some of these studies have been published in the peer-reviewed literature, others have appeared in various reports to the Center for Veterinary Medicine (CVM of the Food and Drug Administration (FDA of the USA as New Animal Drug Application (NADA summaries, and one appeared as a letter to US veterinarians. This review also discusses reports relating to the potential problem of heartworm resistance in microfilariae and third-stage larvae, as well as molecular markers associated with resistance to macrocyclic lactones within Dirofilaria immitis. As more work is being done in this area of great concern relative to the protection of dogs from infection using this class of preventives, it seems timely to summarize what is known about heartworms, their potential resistance to treatment, and the means of selecting for resistance genes in populations of this helminth in the laboratory and in the field.

  17. Hepatocurative potential of sesquiterpene lactones of Taraxacum officinale on carbon tetrachloride induced liver toxicity in mice.

    Science.gov (United States)

    Mahesh, A; Jeyachandran, R; Cindrella, L; Thangadurai, D; Veerapur, V P; Muralidhara Rao, D

    2010-06-01

    The hepatocurative potential of ethanolic extract (ETO) and sesquiterpene lactones enriched fraction (SL) of Taraxacum officinale roots was evaluated against carbon tetrachloride (CCl 4 ) induced hepatotoxicity in mice. The diagnostic markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bilirubin contents were significantly elevated, whereas significant reduction in the level of reduced glutathione (GSH) and enhanced hepatic lipid peroxidation, liver weight and liver protein were observed in CCl 4 induced hepatotoxicity in mice. Post-treatment with ETO and SL significantly protected the hepatotoxicity as evident from the lower levels of hepatic enzyme markers, such as serum transaminase (ALT, AST), ALP and total bilirubin. Further, significant reduction in the liver weight and liver protein in drug-treated hepatotoxic mice and also reduced oxidative stress by increasing reduced glutathione content and decreasing lipid peroxidation level has been noticed. The histopathological evaluation of the liver also revealed that ETO and SL reduced the incidence of liver lesions induced by CCl 4 . The results indicate that sesquiterpene lactones have a protective effect against acute hepatotoxicity induced by the administration of CCl 4 in mice. Furthermore, observed activity of SL may be due to the synergistic action of two sesquiterpene lactones identified from enriched ethyl acetate fraction by HPLC method.

  18. Effects of alpha-tocopherol on lactones in beef headspace during storage.

    Science.gov (United States)

    Watanabe, A; Imanari, M; Higuchi, M; Shiba, N; Yonai, M

    2010-01-01

    We studied the effect of alpha-tocopherol (alpha-Toc) on the production of lactones, a desirable flavor in Wagyu beef (Japanese Black Cattle), in meat headspace. Fresh beef was minced and divided into 4 groups containing different alpha-Toc levels (1.9, 2.7, 6.1, and 10.7 mg/kg) or packed with oxygen absorber. After 10 d of storage at 2 °C, these samples were cooked in distilled water and rendered fat was collected. The headspace of the fat was analyzed with solid-phase microextraction combined with gas chromatography-mass spectrometry. The DB-17MS capillary column led to good separation of aliphatic lactones. Oxygen was important for the development of all lactones during storage. The amounts of gamma-octalactone and gamma-nonalactone decreased linearly with increasing alpha-Toc levels. The effect of alpha-Toc on delta-decalactone, delta-undecalactone, and delta-tetoradecalactone was weaker, and that on delta-hexadecalactone was ambiguous. These observations suggest that oxidation was necessary to develop the flavor of Wagyu beef, and warn that an excessive increase of alpha-Toc could reduce levels of positive flavor components, gamma-octalactone and gamma-nonalactone, in the headspace of Wagyu beef. © 2010 Institute of Food Technologists®

  19. Heliolactone, a non-sesquiterpene lactone germination stimulant for root parasitic weeds from sunflower.

    Science.gov (United States)

    Ueno, Kotomi; Furumoto, Toshio; Umeda, Shuhei; Mizutani, Masaharu; Takikawa, Hirosato; Batchvarova, Rossitza; Sugimoto, Yukihiro

    2014-12-01

    Root exudates of sunflower (Helianthus annuus L.) line 2607A induced germination of seeds of root parasitic weeds Striga hermonthica, Orobanche cumana, Orobanche minor, Orobanche crenata, and Phelipanche aegyptiaca. Bioassay-guided purification led to the isolation of a germination stimulant designated as heliolactone. FT-MS analysis indicated a molecular formula of C20H24O6. Detailed NMR spectroscopic studies established a methylfuranone group, a common structural component of strigolactones connected to a methyl ester of a C14 carboxylic acid via an enol ether bridge. The cyclohexenone ring is identical to that of 3-oxo-α-ionol and the other part of the molecule corresponds to an oxidized carlactone at C-19. It is a carlactone-type molecule and functions as a germination stimulant for seeds of root parasitic weeds. Heliolactone induced seed germination of the above mentioned root parasitic weeds, while dehydrocostus lactone and costunolide, sesquiterpene lactones isolated from sunflower root exudates, were effective only on O. cumana and O. minor. Heliolactone production in aquacultures increased when sunflower seedlings were grown hydroponically in tap water and decreased on supplementation of the culture with either phosphorus or nitrogen. Costunolide, on the other hand, was detected at a higher concentration in well-nourished medium as opposed to nutrient-deficient media, thus suggesting a contrasting contribution of heliolactone and the sesquiterpene lactone to the germination of O. cumana under different soil fertility levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. 银杏内酯研究进展%Research progress in ginkgo terpene lactones

    Institute of Scientific and Technical Information of China (English)

    田青亚; 巩丽丽

    2016-01-01

    Ginkgo terpene lactones is the main active ingredient of ginkgo biloba with high medicinal value,and has been widely used in clinics.This article reviews research from domestic and abroad,including chemical composition,extraction and separation,content detection,and pharmacological activity.We also look into the future research on the ginkgo terpenoid lactones with the aim to provide a reference for the development and utilization of ginkgo terpene lactones.%银杏内酯是银杏叶中的主要活性成分,具有较高的药用价值,在临床上应用广泛.本文综述了近年来国内外学者对银杏内酯化合物的化学成分、提取分离、含量检测、药理活性方面的研究成果,展望了银杏内酯的研究前景,为银杏内酯的进一步开发利用提供参考.

  1. Effect of heterologous expression of acyl-CoA-binding protein on acyl-CoA level and composition in yeast

    DEFF Research Database (Denmark)

    Mandrup, S; Jepsen, R; Skøtt, H

    1993-01-01

    ACBP, i.e. the initiating methionine was removed and the following serine residue was N-acetylated. The expression of this protein did not affect the growth rate of the cells. Determination of the yeast acyl-CoA pool size showed a close positive correlation between the ACBP content of the cells...... and the size of the acyl-CoA pool. Thus ACBP can act as an intracellular acyl-CoA pool former. Possible physiological functions of ACBP in cells are discussed....

  2. Interconvertions between delta-lactam and delta-lactone derivatives initiated by unique transannular interactions of the rigid cyclohexane boat structure in pentacycloundecane.

    Science.gov (United States)

    Kruger, Hendrik G; Martins, Frans J C; Viljoen, Agatha M

    2004-07-09

    The pentacycloundecane (PCU) cage structure resembles a perfect boat conformation, and for the first time unique lactam/lactone interconversions on the flagpole carbons of a cyclohexane boat structure are reported. The syntheses of a novel dihydroxy-PCU-delta-lactone and two novel N-substituted PCU-delta-lactams are reported. Hydrolysis of some of the PCU-delta-lactam compounds produced delta-lactones, and reaction of the lactones with ammonia or primary amines again produced delta-lactams. Reaction mechanisms to account for the unusual interconversion reactions induced by transannular interactions are proposed.

  3. Efficient free fatty acid production in Escherichia coli using plant acyl-ACP thioesterases.

    Science.gov (United States)

    Zhang, Xiujun; Li, Mai; Agrawal, Arpita; San, Ka-Yiu

    2011-11-01

    Microbial biosynthesis of fatty acid-like chemicals from renewable carbon sources has attracted significant attention in recent years. Free fatty acids can be used as precursors for the production of fuels or chemicals. Free fatty acids can be produced by introducing an acyl-acyl carrier protein thioesterase gene into Escherichia coli. The presence of the acyl-ACP thioesterase will break the fatty acid elongation cycle and release free fatty acid. Depending on their sequence similarity and substrate specificity, class FatA thioesterase is active on unsaturated acyl-ACPs and class FatB prefers saturated acyl group. Different acyl-ACP thioesterases have different degrees of chain length specificity. Although some of these enzymes have been characterized from a number of sources, information on their ability to produce free fatty acid in microbial cells has not been extensively examined until recently. In this study, we examined the effect of the overexpression of acyl-ACP thioesterase genes from Diploknema butyracea, Gossypium hirsutum, Ricinus communis and Jatropha curcas on free fatty acid production. In particular, we are interested in studying the effect of different acyl-ACP thioesterase on the quantities and compositions of free fatty acid produced by an E. coli strain ML103 carrying these constructs. It is shown that the accumulation of free fatty acid depends on the acyl-ACP thioesterase used. The strain carrying the acyl-ACP thioesterase gene from D. butyracea produced approximately 0.2g/L of free fatty acid while the strains carrying the acyl-ACP thioesterase genes from R. communis and J. curcas produced the most free fatty acid at a high level of more than 2.0 g/L at 48 h. These two strains accumulated three major straight chain free fatty acids, C14, C16:1 and C16 at levels about 40%, 35% and 20%, respectively.

  4. Acylated flavonol glycosides from the flower of Elaeagnus angustifolia L.

    Science.gov (United States)

    Bendaikha, Sarah; Gadaut, Méredith; Harakat, Dominique; Magid, Alabdul

    2014-07-01

    Seven acylated flavonol glycosides named elaeagnosides A-G, in addition to seven known flavonoids were isolated from the flowers of Elaeagnus angustifolia. Their structures were elucidated by different spectroscopic methods including 1D, 2D NMR experiments and HR-ESI-MS analysis. In order to identify natural antioxidant and tyrosinase inhibitor agents, the abilities of these flavonoids to scavenge the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and to inhibit tyrosinase activity were evaluated. Results revealed that two of these compounds had significant anti-oxidant effect and one compound showed weak tyrosinase-inhibitory activity compared with kojic acid, quercetin, or ascorbic acid, which were used as positive control.

  5. Phosphorylation and Acetylation of Acyl-CoA Synthetase- I

    DEFF Research Database (Denmark)

    Frahm, Jennifer L; Li, Lei O; Grevengoed, Trisha J

    2011-01-01

    Long chain acyl-CoA synthetase 1 (ACSL1) contributes 50 to 90% of total ACSL activity in liver, adipose tissue, and heart and appears to direct the use of long chain fatty acids for energy. Although the functional importance of ACSL1 is becoming clear, little is understood about its post...... and acetylated amino acids by mass spectrometry. We then compared these results to the post-translational modifications observed in vivo in liver and brown adipose tissue after mice were fasted or exposed to a cold environment. We identified universal N-terminal acetylation, 15 acetylated lysines, and 25...

  6. Acylation of Antioxidant of Bamboo Leaves with Fatty Acids by Lipase and the Acylated Derivatives’ Efficiency in the Inhibition of Acrylamide Formation in Fried Potato Crisps

    Science.gov (United States)

    Ma, Xiang; Wang, Erpei; Lu, Yuyun; Wang, Yong; Ou, Shiyi; Yan, Rian

    2015-01-01

    This study selectively acylated the primary hydroxyl groups on flavonoids in antioxidant of bamboo leaves (AOB) using lauric acid with Candida antarctica lipase B in tert-amyl-alcohol. The separation and isolation of acylated derivatives were performed using silica gel column chromatography with a mixture of dichloromethane/diethyl ether/methanol as eluents. Both thin layer chromatography and high-performance liquid chromatography analyses confirmed the high efficiency of the isolation process with the purified orientin-6″-laurate, isoorientin-6″-laurate, vitexin-6″-laurate, and isovitexin-6″-laurate that were obtained. The addition of AOB and acylated AOB reduced acrylamide formation in fried potato crisps. Results showed that 0.05% AOB and 0.05% and 0.1% acylated AOB groups significantly (p acrylamide in potato crisps by 30.7%, 44.5%, and 46.9%, respectively. PMID:26098744

  7. Acylation of Antioxidant of Bamboo Leaves with Fatty Acids by Lipase and the Acylated Derivatives' Efficiency in the Inhibition of Acrylamide Formation in Fried Potato Crisps.

    Science.gov (United States)

    Ma, Xiang; Wang, Erpei; Lu, Yuyun; Wang, Yong; Ou, Shiyi; Yan, Rian

    2015-01-01

    This study selectively acylated the primary hydroxyl groups on flavonoids in antioxidant of bamboo leaves (AOB) using lauric acid with Candida antarctica lipase B in tert-amyl-alcohol. The separation and isolation of acylated derivatives were performed using silica gel column chromatography with a mixture of dichloromethane/diethyl ether/methanol as eluents. Both thin layer chromatography and high-performance liquid chromatography analyses confirmed the high efficiency of the isolation process with the purified orientin-6″-laurate, isoorientin-6″-laurate, vitexin-6″-laurate, and isovitexin-6″-laurate that were obtained. The addition of AOB and acylated AOB reduced acrylamide formation in fried potato crisps. Results showed that 0.05% AOB and 0.05% and 0.1% acylated AOB groups significantly (p < 0.05) reduced the content of acrylamide in potato crisps by 30.7%, 44.5%, and 46.9%, respectively.

  8. Acylation of Antioxidant of Bamboo Leaves with Fatty Acids by Lipase and the Acylated Derivatives' Efficiency in the Inhibition of Acrylamide Formation in Fried Potato Crisps.

    Directory of Open Access Journals (Sweden)

    Xiang Ma

    Full Text Available This study selectively acylated the primary hydroxyl groups on flavonoids in antioxidant of bamboo leaves (AOB using lauric acid with Candida antarctica lipase B in tert-amyl-alcohol. The separation and isolation of acylated derivatives were performed using silica gel column chromatography with a mixture of dichloromethane/diethyl ether/methanol as eluents. Both thin layer chromatography and high-performance liquid chromatography analyses confirmed the high efficiency of the isolation process with the purified orientin-6″-laurate, isoorientin-6″-laurate, vitexin-6″-laurate, and isovitexin-6″-laurate that were obtained. The addition of AOB and acylated AOB reduced acrylamide formation in fried potato crisps. Results showed that 0.05% AOB and 0.05% and 0.1% acylated AOB groups significantly (p < 0.05 reduced the content of acrylamide in potato crisps by 30.7%, 44.5%, and 46.9%, respectively.

  9. 1,5-Anhydro-D-fructose: regioselective acylation with fatty acids

    DEFF Research Database (Denmark)

    Lundt, Inge; Andersen, Søren Møller; Marcussen, Jan;

    1999-01-01

    Regioselective acylation of 1,5-anhydro-D-fructose was performed with dodecanoic acid to give 1,5-anhydro-6-O-dodecanoyl-D-fructose, chemically in 50% yield and enzymatically in quantitative yield. Quantitative conversions were also obtained using hexadecanoic and octadecanoic acids as acyl donors...

  10. Genetics Home Reference: medium-chain acyl-CoA dehydrogenase deficiency

    Science.gov (United States)

    ... Email Facebook Twitter Home Health Conditions MCAD deficiency medium-chain acyl-CoA dehydrogenase deficiency Printable PDF Open ... Javascript to view the expand/collapse boxes. Description Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a ...

  11. Synthesis of acylated methyl beta-D-xylopyranosides and their enzymic deacylations by rabbit serum esterases.

    Science.gov (United States)

    Petrović, V; Tomić, S; Ljevaković, D; Tomasić, J

    1997-07-11

    Selective pivaloylations of methyl beta-D-xylopyranoside have been studied under various reaction conditions. Partially pivaloylated products were submitted to additional acetylations. The structures were established by 1H NMR spectroscopy. Representatives of acylated methyl beta-D-xylopyranosides (acyl being pivaloyl, acetyl, or a combination of both) were submitted to hydrolysis catalyzed by rabbit serum and esterases isolated from rabbit serum.

  12. The Role of Mitochondrial Non-Enzymatic Protein Acylation in Ageing

    Science.gov (United States)

    Hong, Shin Yee; Ng, Li Theng; Ng, Li Fang; Inoue, Takao; Tolwinski, Nicholas S.; Hagen, Thilo; Gruber, Jan

    2016-01-01

    In recent years, various large-scale proteomic studies have demonstrated that mitochondrial proteins are highly acylated, most commonly by addition of acetyl and succinyl groups. These acyl modifications may be enzyme catalysed but can also be driven non-enzymatically. The latter mechanism is promoted in mitochondria due to the nature of the mitochondrial microenvironment, which is alkaline and contains high concentrations of acyl-CoA species. Protein acylation may modify enzyme activity, typically inhibiting it. We posited that organismal ageing might be accompanied by an accumulation of acylated proteins, especially in mitochondria, and that this might compromise mitochondrial function and contribute to ageing. In this study, we used R. norvegicus, C. elegans and D. melanogaster to compare the acylation status of mitochondrial proteins between young and old animals. We observed a specific age-dependent increase in protein succinylation in worms and flies but not in rat. Rats have two substrate-specific mitochondrial deacylases, SIRT3 and SIRT5 while both flies and worms lack these enzymes. We propose that accumulation of mitochondrial protein acylation contributes to age-dependent mitochondrial functional decline and that SIRT3 and SIRT5 enzymes may promote longevity through regulation of mitochondrial protein acylation during ageing. PMID:28033361

  13. Fluorescently labelled bovine acyl-CoA-binding protein acting as an acyl-CoA sensor: interaction with CoA and acyl-CoA esters and its use in measuring free acyl-CoA esters and non-esterified fatty acids

    DEFF Research Database (Denmark)

    Wadum, M.C.; Villadsen, J.K.; Feddersen, S.;

    2002-01-01

    Long-chain acyl-CoA esters are key metabolites in lipid synthesis and b-oxidation but, at the same time, are important regulators of intermediate metabolism, insulin secretion, vesicular trafficking and gene expression. Key tools in studying the regulatory functions of acyl-CoA esters are reliabl...

  14. Acyl-CoA binding proteins; structural and functional conservation over 2000 MYA

    DEFF Research Database (Denmark)

    Faergeman, Nils J; Wadum, Majken; Feddersen, Søren

    2007-01-01

    -CoA binding protein, ACBP, has been proposed to play a pivotal role in the intracellular trafficking and utilization of long-chain fatty acyl-CoA esters. Depletion of acyl-CoA binding protein in yeast results in aberrant organelle morphology incl. fragmented vacuoles, multi-layered plasma membranes...

  15. Suppression of acyl migration in enzymatic production of structured lipids through temperature programming

    DEFF Research Database (Denmark)

    Yang, Tiankui; Fruekilde, Maj-Britt; Xu, Xuebing

    2005-01-01

    Acyl migration in the glycerol backbone often leads to the increase of by-products in the enzymatic production of specific structured lipids. Acyl migration is a thermodynamic process and is very difficult to stop fully in actual reactions. The objective of this study was to investigate the feasi......Acyl migration in the glycerol backbone often leads to the increase of by-products in the enzymatic production of specific structured lipids. Acyl migration is a thermodynamic process and is very difficult to stop fully in actual reactions. The objective of this study was to investigate...... the feasibility of suppressing acyl migration by a programmed change of reaction temperature without loss of reaction yield. The model reactions were the acidolysis of tripalmitin with conjugated linoleic acid (CLA) or with caprylic acid (CA) targeted for human milk fat substitutes. Acyl migration...... was considerably inhibited in the temperature-programmed acidolysis of PPP with CLA or CA, with only slight reduction of acyl incorporation, the reaction leading to the required products. Acyl migration was reduced by 29% (35 h) and 45% (48 h), respectively, in the acidolysis of PPP with CLA under solvent...

  16. Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride.

    Science.gov (United States)

    Li, Conghu; Tian, Zhenhua; Liu, Wentao; Li, Guoying

    2015-10-01

    The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen.

  17. A simple, effective, green method for regioselective 3-acylation of unprotected indoles

    DEFF Research Database (Denmark)

    Tran, Phuong Huong; Tran, Hai N.; Hansen, Poul Erik;

    2015-01-01

    A fast and green method is developed for regioselective acylation of indoles in the 3-position without the need for protection of the NH position. The method is based on Friedel-Crafts acylation using acid anhydrides. The method has been optimized, and Y(OTf)3 in catalytic amounts is found...

  18. Stereoelectronic basis for the kinetic resolution of N-heterocycles with chiral acylating reagents.

    Science.gov (United States)

    Hsieh, Sheng-Ying; Wanner, Benedikt; Wheeler, Philip; Beauchemin, André M; Rovis, Tomislav; Bode, Jeffrey W

    2014-06-10

    The kinetic resolution of N-heterocycles with chiral acylating agents reveals a previously unrecognized stereoelectronic effect in amine acylation. Combined with a new achiral hydroxamate, this effect makes possible the resolution of various N-heterocycles by using easily prepared reagents. A transition-state model to rationalize the stereochemical outcome of this kinetic resolution is also proposed.

  19. Acyl-CoA-binding protein/diazepam-binding inhibitor gene and pseudogenes

    DEFF Research Database (Denmark)

    Mandrup, S; Hummel, R; Ravn, S

    1992-01-01

    Acyl-CoA-binding protein (ACBP) is a 10 kDa protein isolated from bovine liver by virtue of its ability to bind and induce the synthesis of medium-chain acyl-CoA esters. Surprisingly, it turned out to be identical to a protein named diazepam-binding Inhibitor (DBI) claimed to be an endogenous mod...

  20. Acylation of aromatic alcohols and phenols over InCl3/montmorillonite K-10 catalysts

    Indian Academy of Sciences (India)

    Vasant R Choudhary; Kailash Y Patil; Suman K Jana

    2004-03-01

    Montmorillonite K-10 clay supported InCl3 is a highly active catalyst for the acylation of aromatic alcohols and phenols with different acyl chlorides. This catalyst can be reused in reactions a number of times without very significant loss of catalytic activity.

  1. Influence of Lipid A Acylation Pattern on Membrane Permeability and Innate Immune Stimulation

    Directory of Open Access Journals (Sweden)

    Robert K. Ernst

    2013-08-01

    Full Text Available Lipid A, the hydrophobic anchor of lipopolysaccharide (LPS, is an essential component in the outer membrane of Gram-negative bacteria. It can stimulate the innate immune system via Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD2, leading to the release of inflammatory cytokines. In this study, six Escherichia coli strains which can produce lipid A with different acylation patterns were constructed; the influence of lipid A acylation pattern on the membrane permeability and innate immune stimulation has been systematically investigated. The lipid A species were isolated and identified by matrix assisted laser ionization desorption-time of flight/tandem mass spectrometry. N-Phenyl naphthylamine uptake assay and antibiotic susceptibility test showed that membrane permeability of these strains were different. The lower the number of acyl chains in lipid A, the stronger the membrane permeability. LPS purified from these strains were used to stimulate human or mouse macrophage cells, and different levels of cytokines were induced. Compared with wild type hexa-acylated LPS, penta-acylated, tetra-acylated and tri-acylated LPS induced lower levels of cytokines. These results suggest that the lipid A acylation pattern influences both the bacterial membrane permeability and innate immune stimulation. The results would be useful for redesigning the bacterial membrane structure and for developing lipid A vaccine adjuvant.

  2. P53 Mutations Change Phosphatidylinositol Acyl Chain Composition

    Directory of Open Access Journals (Sweden)

    Adam Naguib

    2015-01-01

    Full Text Available Phosphatidylinositol phosphate (PIP second messengers relay extracellular growth cues through the phosphorylation status of the inositol sugar, a signal transduction system that is deregulated in cancer. In stark contrast to PIP inositol head-group phosphorylation, changes in phosphatidylinositol (PI lipid acyl chains in cancer have remained ill-defined. Here, we apply a mass-spectrometry-based method capable of unbiased high-throughput identification and quantification of cellular PI acyl chain composition. Using this approach, we find that PI lipid chains represent a cell-specific fingerprint and are unperturbed by serum-mediated signaling in contrast to the inositol head group. We find that mutation of Trp53 results in PIs containing reduced-length fatty acid moieties. Our results suggest that the anchoring tails of lipid second messengers form an additional layer of PIP signaling in cancer that operates independently of PTEN/PI3-kinase activity but is instead linked to p53.

  3. Acylation of salmon calcitonin modulates in vitro intestinal peptide flux through membrane permeability enhancement.

    Science.gov (United States)

    Trier, Sofie; Linderoth, Lars; Bjerregaard, Simon; Strauss, Holger M; Rahbek, Ulrik L; Andresen, Thomas L

    2015-10-01

    Acylation of peptide drugs with fatty acid chains has proven beneficial for prolonging systemic circulation, as well as increasing enzymatic stability and interactions with lipid cell membranes. Thus, acylation offers several potential benefits for oral delivery of therapeutic peptides, and we hypothesize that tailoring the acylation may be used to optimize intestinal translocation. This work aims to characterize acylated analogues of the therapeutic peptide salmon calcitonin (sCT), which lowers blood calcium, by systematically increasing acyl chain length at two positions, in order to elucidate its influence on intestinal cell translocation and membrane interaction. We find that acylation drastically increases in vitro intestinal peptide flux and confers a transient permeability enhancing effect on the cell layer. The analogues permeabilize model lipid membranes, indicating that the effect is due to a solubilization of the cell membrane, similar to transcellular oral permeation enhancers. The effect is dependent on pH, with larger effect at lower pH, and is impacted by acylation chain length and position. Compared to the unacylated peptide backbone, N-terminal acylation with a short chain provides 6- or 9-fold increase in peptide translocation at pH 7.4 and 5.5, respectively. Prolonging the chain length appears to hamper translocation, possibly due to self-association or aggregation, although the long chain acylated analogues remain superior to the unacylated peptide. For K(18)-acylation a short chain provides a moderate improvement, whereas medium and long chain analogues are highly efficient, with a 12-fold increase in permeability compared to the unacylated peptide backbone, on par with currently employed oral permeation enhancers. For K(18)-acylation the medium chain acylation appears to be optimal, as elongating the chain causes greater binding to the cell membrane but similar permeability, and we speculate that increasing the chain length further may

  4. N-acyl phosphatidylethanolamines affect the lateral distribution of cholesterol in membranes

    DEFF Research Database (Denmark)

    Térová, B.; Slotte, J.P.; Petersen, G.

    2005-01-01

    -acyl-POPE) or N-acyl-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (N-acyl-DPPE), and how the molecules interacted with cholesterol. The gel ¿ liquid crystalline transition temperature of sonicated N-acyl phosphatidylethanolamine vesicles in water correlated positively with the number of palmitic acyl chains...... in the molecules. Based on diphenylhexatriene steady state anisotropy measurements, the presence of 33 mol% cholesterol in the membranes removed the phase transition from N-oleoyl-POPE bilayers, but failed to completely remove it from N-palmitoyl-DPPE and N-palmitoyl-POPE bilayers, suggesting rather weak...... interaction of cholesterol with the N-saturated NAPEs. The rate of cholesterol desorption from mixed monolayers containing N-palmitoyl-DPPE and cholesterol (1:1 molar ratio) was much higher compared to cholesterol/DPPE binary monolayers, suggesting a weak cholesterol interaction with N-palmitoyl-DPPE also...

  5. Biochemistry of lactone formation in yeast and fungi and its utilisation for the production of flavour and fragrance compounds.

    Science.gov (United States)

    Romero-Guido, Cynthia; Belo, Isabel; Ta, Thi Minh Ngoc; Cao-Hoang, Lan; Alchihab, Mohamed; Gomes, Nelma; Thonart, Philippe; Teixeira, Jose A; Destain, Jacqueline; Waché, Yves

    2011-02-01

    The consumers' demand for natural flavour and fragrances rises. To be natural, compounds have to result from the extraction of natural materials and/or to be transformed by natural means such as the use of enzymes or whole cells. Fungi are able to transform some fatty acids into lactones that can thus be natural. Although some parts of this subject have been reviewed several times, the present article proposes to review the different pathways utilised, the metabolic engineering strategies and some current concerns on the reactor application of the transformation including scaling up data. The main enzymatic steps are hydroxylation and β-oxidation in the traditional way, and lactone desaturation or Baeyer-Villiger oxidation. Although the pathway to produce γ-decalactone is rather well known, metabolic engineering strategies may result in significant improvements in the productivity. For the production of other lactones, a key step is the hydroxylation of fatty acids. Beside the biotransformation, increasing the production of the various lactones requires from biotechnologists to solve two main problems which are the toxicity of lactones toward the producing cell and the aeration of the emulsified reactor as the biochemical pathway is very sensitive to the level of available oxygen. The strategies employed to resolve these problems will be presented.

  6. Substantial species differences in relation to formation and degradation of N-acyl-ethanolamine phospholipids in heart tissue

    DEFF Research Database (Denmark)

    Moesgaard, B.; Petersen, G.; Hansen, Harald S.

    2002-01-01

    The formation of N-acyl-ethanolamines (NAEs), including the cannabinoid receptor ligand anandamide, and their precursors N-acyl-ethanolamine phospholipids (NAPEs) are catalyzed by NAPE-hydrolyzing phospholipase D (NAPE-PLD) and N-acyl-transferase, respectively. NAPE and NAE are suggested to have...

  7. Relationships between acylated ghrelin with growth hormone, insulin resistance, lipid profile, and cardio respiratory function in lean and obese men

    Directory of Open Access Journals (Sweden)

    Hasan Matin Homaee

    2011-01-01

    Conclusions: Obese and lean inactive young men had different levels of acylated ghrelin, GH, insulin, insulin resistance index, cardiorespiratory function and body fat percent. Body fat percent, insulin, and GH levels appear to be best determinant factors of acylated ghrelin levels. Also, in both obese and lean young men, higher levels of cardiovascular function were associated with higher levels of acylated ghrelin.

  8. 40 CFR 721.7270 - 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs., chloride.

    Science.gov (United States)

    2010-07-01

    ...-trimethyl-N-soya acyl derivs., chloride. 721.7270 Section 721.7270 Protection of Environment ENVIRONMENTAL...-soya acyl derivs., chloride. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1-propanaminium, 3-amino-, N,N,N-trimethyl-N-soya acyl derivs...

  9. 40 CFR 721.10056 - Benzenemethanaminium, N-(3-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides.

    Science.gov (United States)

    2010-07-01

    ...)-N,N-dimethyl-, N-soya acyl derivs., chlorides. 721.10056 Section 721.10056 Protection of Environment...-aminopropyl)-N,N-dimethyl-, N-soya acyl derivs., chlorides. (a) Chemical substance and significant new uses...-dimethyl-, N-soya acyl derivs., chlorides (PMN P-03-47; CAS No. 90194-13-1) is subject to reporting under...

  10. Quorum sensing inhibitory potential and molecular docking studies of sesquiterpene lactones from Vernonia blumeoides.

    Science.gov (United States)

    Aliyu, Abubakar Babando; Koorbanally, Neil Anthony; Moodley, Brenda; Singh, Parvesh; Chenia, Hafizah Yousuf

    2016-06-01

    The increasing incidence of multidrug-resistant Gram-negative bacterial pathogens has focused research on the suppression of bacterial virulence via quorum sensing inhibition strategies, rather than the conventional antimicrobial approach. The anti-virulence potential of eudesmanolide sesquiterpene lactones previously isolated from Vernonia blumeoides was assessed by inhibition of quorum sensing and in silico molecular docking. Inhibition of quorum sensing-controlled violacein production in Chromobacterium violaceum was quantified using violacein inhibition assays. Qualitative modulation of quorum sensing activity and signal synthesis was investigated using agar diffusion double ring assays and C. violaceum and Agrobacterium tumefaciens biosensor systems. Inhibition of violacein production was concentration-dependent, with ⩾90% inhibition being obtained with ⩾2.4 mg ml(-1) of crude extracts. Violacein inhibition was significant for the ethyl acetate extract with decreasing inhibition being observed with dichloromethane, hexane and methanol extracts. Violacein inhibition ⩾80% was obtained with 0.071 mg ml(-1) of blumeoidolide B in comparison with ⩾3.6 mg ml(-1) of blumeoidolide A. Agar diffusion double ring assays indicated that only the activity of the LuxI synthase homologue, CviI, was modulated by blumeoidolides A and B, and V. blumeoides crude extracts, suggesting that quorum sensing signal synthesis was down-regulated or competitively inhibited. Finally, molecular docking was conducted to explore the binding conformations of sesquiterpene lactones into the binding sites of quorum sensing regulator proteins, CviR and CviR'. The computed binding energy data suggested that the blumeoidolides have a tendency to inhibit both CviR and CviR' with varying binding affinities. Vernonia eudesmanolide sesquiterpene lactones have the potential to be novel therapeutic agents, which might be important in reducing virulence and pathogenicity of drug-resistant bacteria

  11. Sesquiterpene Lactones from Gynoxys verrucosa and their Anti-MRSA Activity

    Science.gov (United States)

    Ordóñez, Paola E.; Quave, Cassandra L.; Reynolds, William F.; Varughese, Kottayil I.; Berry, Brian; Breen, Philip J.; Malagón, Omar; Smeltzer, Mark S.; Compadre, Cesar M.

    2011-01-01

    Ethnopharmacological relevance Because of its virulence and antibiotic resistance, Staphylococcus aureus is a more formidable pathogen now than at any time since the pre-antibiotic era. In an effort to identify and develop novel antimicrobial agents with activity against this pathogen, we have examined Gynoxys verrucosa Wedd (Asteraceae), an herb used in traditional medicine in southern Ecuador for the treatment and healing of wounds. Materials and Methods The sesquiterpene lactones leucodine (1) and dehydroleucodine (2) were extracted and purified from the aerial parts of G. verrucosa, and their structure was elucidated by spectroscopic methods and single-crystal X-ray analysis. The in vitro anti-microbial activity of G. verrucosa extracts and its purified constituents was determined against six clinical isolates including S. aureus and Staphylococcus epidermidis strains with different drug-resistance profiles, using the microtiter broth method. Results Compound 1 has very low activity, while compound 2 has moderate activity with MIC50s between 49 and195 μg/mL. The extract of G. verrucosa has weak activity with MIC50s between 908 and 3290 μg/mL. Conclusions We are reporting the full assignment of the 1H-NMR and 13C-NMR of both compounds, and the crystal structure of compound 2, for the first time. Moreover, the fact that compound 2 has antimicrobial activity and compound 1 does not, demonstrates that the exocyclic conjugated methylene in the lactone ring is essential for the antimicrobial activity of these sesquiterpene lactones. However, the weak activity observed for the plants extracts, does not explain the use of G. verrucosa in traditional medicine for the treatment of wounds and skin infections. PMID:21782013

  12. HIGH PERFORMANCE LIQUID CHROMATOGRAPHY USE IN ANALYSIS OF SESQUITERPENIC LACTONES OF LAURUS NOBILIS

    Directory of Open Access Journals (Sweden)

    S. P. Senchenko

    2015-01-01

    Full Text Available We have developed a methodology of quantitative determination of sesquiterpenic lactones (costunolide and dehydrocostuslactone in leaves of Laurus nobilis using reversed phase HPLC. We have determined optimal conditions for the substances under study extraction from active parts. Using the developed methods we have established that costunolide and dehydrocostuslactone content in Laurus nobilis samples in terms of absolutely dry active parts is 0.99 and 0.26% correspondingly.

  13. A new sesquiterpene lactone and a new aromatic glycoside from Illicium difengpi

    Directory of Open Access Journals (Sweden)

    Lei Fang

    2011-10-01

    Full Text Available A new sesquiterpene lactone (1 and a new aromatic glycoside (2, together with three known compounds (3–5 were isolated from the stem bark of Illicium difengpi K. I. B et K. I. M. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRESIMS, and chemical methods. The absolute configuration of the secondary alcohol in 1 was confirmed by Mosher's method. Compound 2 exhibited significant anti-inflammatory activity with IC50 value of 6.72 μmol/L.

  14. Origin of Kinetic Resolution of Hydroxy Esters through Catalytic Enantioselective Lactonization by Chiral Phosphoric Acids.

    Science.gov (United States)

    Changotra, Avtar; Sunoj, Raghavan B

    2016-08-05

    Kinetic resolution is a widely used strategy for separation and enrichment of enantiomers. Using density functional theory computations, the origin of how a chiral BINOL-phosphoric acid catalyzes the selective lactonization of one of the enantiomers of α-methyl γ-hydroxy ester is identified. In a stepwise mechanism, the stereocontrolling transition state for the addition of the hydroxyl group to the si face of the ester carbonyl in the case of the S isomer exhibits a network of more effective noncovalent interactions between the substrate and the chiral catalyst.

  15. Routine patch testing with the sesquiterpene lactone mix in Europe: a 2-year experience

    DEFF Research Database (Denmark)

    Paulsen, E; Andersen, Klaus Ejner; Brandão, F M

    1999-01-01

    To test the screening value of the sesquiterpene lactone (SL) mix in Europe today and describe epidemiological and clinical features of Compositae-sensitive patients, the SL mix 0.1% pet. was included in the standard patch test series in 11 European clinics. 10,695 patients were tested, and 106 (1...... proportion of the patients. More than 1/3 were positive to perfume and/or colophony, possibly reflecting cross-reactivity. With only 1 case of active sensitization and no irritant reactions, the SL mix is a safe allergen and the overall prevalence of positive reactions supports its continued use...

  16. Microphynolides A and B, new spiro-γ-lactone glycosides from Thymelaea microphylla.

    Science.gov (United States)

    Ghanem, Hasna; Haba, Hamada; Marcourt, Laurence; Benkhaled, Mohammed; Wolfender, Jean-Luc

    2014-01-01

    Two new spiro-γ-lactone glycosides named microphynolide A (1) and microphynolide B (2), together with twelve known compounds including five biflavonoids namely neochamaejasmin A, neochamaejasmin B, daphnodorin B, genkwanol A and stelleranol, one bis-coumarin daphnoretin, two lignans called pinoresinol and matairesinol, one flavonoid glucoside, tiliroside, a sinapyl alcohol glucoside, syringin, and two phytosterols, β-sitosterol and β-sitosterol-3-O-glucoside, were isolated from ethyl acetate extracts of the aerial parts and roots of the plant Thymelaea microphylla Coss. and Dur. All the isolated compounds were characterised by using spectroscopic methods and comparison with the literature data.

  17. Synthesis and antifungal activity of new bis-{gamma}-lactones analogous to avenaciolide

    Energy Technology Data Exchange (ETDEWEB)

    Magaton, Andreia da Silva; Rubinger, Mayura M. M.; Macedo Junior, Fernando C. de [Vicosa Univ., MG (Brazil). Dept. de Quimica]. E-mail: mayura@ufv.br; Zambolim, Laercio [Vicosa Univ., MG (Brazil). Dept. de Fitopatologia

    2007-03-15

    In a study of the antifungal activity of selected compounds as potentials agrochemicals, we have prepared and characterized by elemental analyses, infrared and NMR spectroscopies three new bis-{gamma}-lactones analogous to avenaciolide, where the octyl group of this natural product was replaced by heptyl, hexyl and pentyl groups. The effects on the mycelia development and conidia germination of Colletotrichum gloesporioides of these compounds and their synthetic precursors were evaluated in vitro. The title compounds were active in the tested conditions, while all the synthetic precursors were inactive. The preparation and characterization of 15 new synthetic intermediates are also described. (author)

  18. In vitro anti-parasitic effects of sesquiterpene lactones from chicory against cattle nematodes

    DEFF Research Database (Denmark)

    Pena-Espinoza, Miguel Angel; Williams, A.; Boas, Ulrik

    Chicory (Cichorium intybus) is currently being investigated for potential use as an anti-parasitic crop for ruminants. However, mechanisms behind observed in vivo effects are poorly understood but it is likely that plant secondary metabolites like sesquiterpene lactones (SL) play a role......-SL induced a larval mortality of only 37% at the highest concentration tested (2000 μg/mL), thus estimation of EC50 was not possible. Results showed a marked difference in the anti-parasitic activity of SL-rich extracts from 2 different chicory cultivars. Further biochemical analyses of the extracts may...

  19. In vitro anti-parasitic effects of sesquiterpene lactones from chicory against cattle nematodes

    DEFF Research Database (Denmark)

    Pena-Espinoza, Miguel Angel; Williams, A.; Boas, Ulrik

    Chicory (Cichorium intybus) has the potential as an anti-parasitic crop for ruminants. However, the mechanisms behind observed in vivo effects are poorly understood but it is likely that plant secondary metabolites like sesquiterpene lactones (SL) play a role. In this study we tested the effect......, Puna-SL induced a larval mortality of only 37% at the highest concentration tested (2,000 μg/ml), thus estimation of EC50 was not possible. Results showed a marked difference in the anti-parasitic activity of SL-rich extracts from 2 different chicory cultivars. Further biochemical analyses...

  20. Synthesis and antifungal activity of halogenated aromatic bis-γ-lactones analogous to avenaciolide

    Directory of Open Access Journals (Sweden)

    Pedro A. Castelo-Branco

    2012-01-01

    Full Text Available Here we describe the total syntheses and characterization by elemental analyses, infrared and NMR spectroscopy of three new compounds analogous to avenaciolide, a bis-γ-lactone isolated from Aspergillus avenaceus that possesses antifungal activity, where the octyl group of the natural product was replaced by aromatic groups containing chlorine and fluorine atoms. The effects of the avenaciolide, the novel compounds and their synthetic precursors on mycelia development and conidia germination of Colletotrichum gloeosporioides and Fusarium solani were evaluated in vitro. The title compounds were almost as active as avenaciolide. The absolute structures of the chlorinated analogs were determined by X-ray diffraction analysis.