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Sample records for autoinducer dodecanoyl-homoserine lactone

  1. 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

    . 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....... Finally, C-12-HSL-treated cells also had a time-course-dependent higher concentration of ODC mRNA. Based on these mitotic markers, more human cells were apparently trapped in the mitotic phase when treated with C-12-HSL. This should normally imply higher levels of putrescine. However, C-12-HSL......-treated human cells had a significantly lower concentration of putrescine and displayed a lower cell proliferation rate. In conclusion, the P. aeruginosa autoinducer C-12-oxo-HSL apparently arrests human cells in the mitotic phase by lowering the concentration of putrescine....

  2. Molecular Basis for the Recognition of Structurally Distinct Autoinducer Mimics by the Pseudomonas aeruginosa LasR Quorum-Sensing Signaling Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Yaozhong; Nair, Satish K.; (UIUC)

    2010-01-12

    The human pathogen Pseudomonas aeruginosa coordinates the expression of virulence factors using quorum sensing, a signaling cascade triggered by the activation of signal receptors by small-molecule autoinducers. These homoserine lactone autoinducers stabilize their cognate receptors and activate their functions as transcription factors. Because quorum sensing regulates the progression of infection and host immune resistance, significant efforts have been devoted toward the identification of small molecules that disrupt this process. Screening efforts have identified a class of triphenyl compounds that are structurally distinct from the homoserine lactone autoinducer, yet interact specifically and potently with LasR receptor to modulate quorum sensing (Muh et al., 2006a). Here we present the high-resolution crystal structures of the ligand binding domain of LasR in complex with the autoinducer N-3-oxo-dodecanoyl homoserine lactone (1.4 {angstrom} resolution), and with the triphenyl mimics TP-1, TP-3, and TP-4 (to between 1.8 {angstrom} and 2.3 {angstrom} resolution). These crystal structures provide a molecular rationale for understanding how chemically distinct compounds can be accommodated by a highly selective receptor, and provide the framework for the development of novel quorum-sensing regulators, utilizing the triphenyl scaffold.

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

    Science.gov (United States)

    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.

  4. 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.

  5. 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...... 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....

  6. 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...... 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....

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Cell density-dependent modulation of the Vibrio fischeri luminescence system in the absence of autoinducer and LuxR protein.

    OpenAIRE

    1992-01-01

    Expression of the Vibrio fischeri luminescence genes (luxR and luxICDABEG) in Escherichia coli requires autoinducer (N-3-oxohexanoyl homoserine lactone) and LuxR protein, which activate transcription of luxICDABEG (genes for autoinducer synthase and the luminescence enzymes), and cyclic AMP (cAMP) and cAMP receptor protein (CRP), which activate transcription of the divergently expressed luxR gene. In E. coli and in V. fischeri, the autoinducer-LuxR protein-dependent induction of luxICDABEG tr...

  13. Improved bioassay for detecting autoinducer of Rhodovulum sulfidophilum

    Science.gov (United States)

    Terada, T.; Kikuchi, Y.; Umekage, S.

    2015-02-01

    Quorum sensing is a bacterial gene regulation system that enables prompt environmental adaptation in response to cell density. Quorum sensing is driven by an extracellularly secreted chemical signal called autoinducer. Gram-negative bacteria produce one or several types of N-acylhomoserine lactone (AHL) as autoinducers. Our previous study suggests that the gram-negative marine photosynthetic bacterium Rhodovulum sulfidophilum produces AHL in the early stationary phase and plays a role in maintaining the bacterial cell aggregates called "floc". We performed conventional bioassay to identify AHL production by using Chromobacterium violaceum VIR07, which produces violet pigment (violacein) in response to AHL with side chains ranging from C10 to C18 in length. However, we were not able to observe the violacein with good reproducibility, suggesting that inhibitory chemical compounds co-existed in the AHL extract. Therefore, we improved the extraction method; the ethyl acetate-extracted AHLs were fractionated by using reverse phase TLC. By using the re-extracted AHLs for the bioassay, we observed an obvious production of violacein. This result clearly indicates that R. sulfidophilum produces AHLs with side chains ranging from C10 to C18 in length and suggests the utility of improved bioassay for AHL detection.

  14. 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

  15. 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.

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

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    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.

  17. Effects of quorum sensing autoinducer degradation gene on virulence and biofilm formation of Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    WANG Yao; DAI Yue; ZHANG Yong; HU YangBo; YANG BaoYu; CHEN ShiYun

    2007-01-01

    The aiiA gene from Bacillus thuringiensis was cloned into the Pseudomonas/E. coli shuttle vector and transformed into Pseudomonas aeruginosa strain PAO1. Western blotting showed that the AiiA protein was expressed in PAO1. After induction by IPTG for 6 h and 18 h, expression of the aiiA gene in PAO1completely degraded the quorum sensing autoinducers N-acylhomoserine lactones (AHLs):N-oxododecanoyI-L-homoserine lactone (OdDHL) and N-butyryI-L-homoserine lactone (BHL). The reduced amount of AHLs in PAO1 was also correlated with decreased expression and production of several virulence factors such as elastase and pyocyanin. AiiA expression also influenced bacterial swarming motility. Most importantly, our studies indicated that aiiA played significant roles in P.aeruginosa biofilm formation and dispersion, as observed by the differences of the biofilm formation on liquid and solid surfaces, and biofilm structures under a scanning electron microscope.

  18. Effects of quorum sensing autoinducer degradation gene on virulence and biofilm formation of Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The aiiA gene from Bacillus thuringiensis was cloned into the Pseudomonas/E. coli shuttle vector and transformed into Pseudomonas aeruginosa strain PAO1. Western blotting showed that the AiiA protein was expressed in PAO1. After induction by IPTG for 6 h and 18 h, expression of the aiiA gene in PAO1 completely degraded the quorum sensing autoinducers N-acylhomoserine lactones (AHLs): N-oxododecanoyl-L-homoserine lactone (OdDHL) and N-butyryl-L-homoserine lactone (BHL). The re- duced amount of AHLs in PAO1 was also correlated with decreased expression and production of several virulence factors such as elastase and pyocyanin. AiiA expression also influenced bacterial swarming motility. Most importantly, our studies indicated that aiiA played significant roles in P. aeruginosa biofilm formation and dispersion, as observed by the differences of the biofilm formation on liquid and solid surfaces, and biofilm structures under a scanning electron microscope.

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

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    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.

  20. Autoinducer-2 of the fire blight pathogen Erwinia amylovora and other plant-associated bacteria.

    Science.gov (United States)

    Mohammadi, Mojtaba; Geider, Klaus

    2007-01-01

    Autoinducers are important for cellular communication of bacteria. The luxS gene has a central role in the synthesis of autoinducer-2 (AI-2). The gene was identified in a shotgun library of Erwinia amylovora and primers designed for PCR amplification from bacterial DNA. Supernatants of several Erwinia amylovora strains were assayed for AI-2 activity with a Vibrio harveyi mutant and were positive. Many other plant-associated bacteria also showed AI-2 activity such as Erwinia pyrifoliae and Erwinia tasmaniensis. The luxS genes of several bacteria were cloned, sequenced, and complemented Escherichia coli strain DH5alpha and a Salmonella typhimurium mutant, both defective in luxS, for synthesis of AI-2. Assays to detect AI-2 activity in culture supernatants of several Pseudomonas syringae pathovars failed, which may indicate the absence of AI-2 or synthesis of another type. Several reporter strains did not detect synthesis of an acyl homoserine lactone (AHL, AI-1) by Erwinia amylovora, but confirmed AHL-synthesis for Erwinia carotovora ssp. atroseptica and Pantoea stewartii.

  1. 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.

  2. Quorum-sensing regulates biofilm formation in Vibrio scophthalmi

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    García-Aljaro Cristina

    2012-12-01

    Full Text Available Abstract Background In a previous study, we demonstrated that Vibrio scophthalmi, the most abundant Vibrio species among the marine aerobic or facultatively anaerobic bacteria inhabiting the intestinal tract of healthy cultured turbot (Scophthalmus maximus, contains at least two quorum-sensing circuits involving two types of signal molecules (a 3-hydroxy-dodecanoyl-homoserine lactone and the universal autoinducer 2 encoded by luxS. The purpose of this study was to investigate the functions regulated by these quorum sensing circuits in this vibrio by constructing mutants for the genes involved in these circuits. Results The presence of a homologue to the Vibrio harveyi luxR gene encoding a main transcriptional regulator, whose expression is modulated by quorum–sensing signal molecules in other vibrios, was detected and sequenced. The V. scophthalmi LuxR protein displayed a maximum amino acid identity of 82% with SmcR, the LuxR homologue found in Vibrio vulnificus. luxR and luxS null mutants were constructed and their phenotype analysed. Both mutants displayed reduced biofilm formation in vitro as well as differences in membrane protein expression by mass-spectrometry analysis. Additionally, a recombinant strain of V. scophthalmi carrying the lactonase AiiA from Bacillus cereus, which causes hydrolysis of acyl homoserine lactones, was included in the study. Conclusions V. scophthalmi shares two quorum sensing circuits, including the main transcriptional regulator luxR, with some pathogenic vibrios such as V. harveyi and V. anguillarum. However, contrary to these pathogenic vibrios no virulence factors (such as protease production were found to be quorum sensing regulated in this bacterium. Noteworthy, biofilm formation was altered in luxS and luxR mutants. In these mutants a different expression profile of membrane proteins were observed with respect to the wild type strain suggesting that quorum sensing could play a role in the regulation of

  3. Initial detection of the quorum sensing autoinducer activity in the rumen of goats in vivo andin vitro

    Institute of Scientific and Technical Information of China (English)

    RAN Tao; ZHOU Chuan-she; XU Li-wei; GENG Mei-mei; TAN Zhi-liang; TANG Shao-xun; WANG Min; HAN Xue-feng; KANG Jin-he

    2016-01-01

    Quorum sensing (QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cel-cel signaling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminaly ifs-tulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers (AI) bothin vivo andin vitroand to clone theluxS gene that encoded autoinducer-2 (AI-2) synthase of microbial samples that were colected from the rumen of goats. Neutral detergent ifber (NDF) and soluble starch were the two types of substrates that were used forin vitro fermentation. The fermented lfuid samples were colected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones (AHLs) activity was determined using gas chromatography-mass spectrometer (GC-MS) analysis. However, none of the rumen lfuid extracts that were colected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using aVibrio harveyi BB170 bioassay, was negative in al samples that were colected from the goat rumen and fromin vitro fermentation lfuids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal lfuids obtained fromin vitro fermentation at different sampling time-points. However, the homologues ofluxS in Prevotela ruminicola were cloned fromin vivo and in vitroruminal lfuids. We concluded that AHLs and AI-2 could not be detected in in vivo andin vitro ruminal lfuids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each othervia AI-2-mediated QS because of the presence ofluxS.

  4. 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.

  5. 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)....

  6. Truncated Autoinducing Peptides as Antagonists of Staphylococcus lugdunensis Quorum Sensing.

    Science.gov (United States)

    Gordon, Christopher P; Olson, Shondra D; Lister, Jessica L; Kavanaugh, Jeffrey S; Horswill, Alexander R

    2016-10-13

    Competitive quorum sensing (QS) antagonism offers a novel strategy for attenuating current multidrug resistant staphylococcal infections. To this end, a series of 10 truncated analogues based on the parent autoinducing peptides (AIPs) of Staphylococcus lugdunensis (groups I and II) and Staphylococcus epidermidis (groups I-III) were sequentially assessed against a newly developed Staphylococcus lugdunensis group I QS reporter strain. The truncated analogues based upon Staphylococcus lugdunensis AIP-1 (1) and AIP-2 (2) displayed respective IC50 values of 0.2 ± 0.01 μM and 0.3 ± 0.01 μM, while the truncated analogue of the Staphylococcus epidermidis AIP-1 (3) elicited an IC50 value of 2.7 ± 0.1 μM. These findings demonstrate the potential of cognate and "crosstalk" competitive quorum sensing inhibition using truncated AIPs as a means of attenuating staphylococcal infections in species beyond Staphylococcus aureus.

  7. 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.

  8. 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.

  9. 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

  10. Analysis of Autoinducer-2 Quorum Sensing in Yersinia pestis

    Science.gov (United States)

    Yu, Jing; Madsen, Melissa L.; Carruthers, Michael D.; Phillips, Gregory J.; Kavanaugh, Jeffrey S.; Boyd, Jeff M.; Horswill, Alexander R.

    2013-01-01

    The autoinducer-2 (AI-2) quorum-sensing system has been linked to diverse phenotypes and regulatory changes in pathogenic bacteria. In the present study, we performed a molecular and biochemical characterization of the AI-2 system in Yersinia pestis, the causative agent of plague. In strain CO92, the AI-2 signal is produced in a luxS-dependent manner, reaching maximal levels of 2.5 μM in the late logarithmic growth phase, and both wild-type and pigmentation (pgm) mutant strains made equivalent levels of AI-2. Strain CO92 possesses a chromosomal lsr locus encoding factors involved in the binding and import of AI-2, and confirming this assignment, an lsr deletion mutant increased extracellular pools of AI-2. To assess the functional role of AI-2 sensing in Y. pestis, microarray studies were conducted by comparing Δpgm strain R88 to a Δpgm ΔluxS mutant or a quorum-sensing-null Δpgm ΔypeIR ΔyspIR ΔluxS mutant at 37°C. Our data suggest that AI-2 quorum sensing is associated with metabolic activities and oxidative stress genes that may help Y. pestis survive at the host temperature. This was confirmed by observing that the luxS mutant was more sensitive to killing by hydrogen peroxide, suggesting a potential requirement for AI-2 in evasion of oxidative damage. We also show that a large number of membrane protein genes are controlled by LuxS, suggesting a role for quorum sensing in membrane modeling. Altogether, this study provides the first global analysis of AI-2 signaling in Y. pestis and identifies potential roles for the system in controlling genes important to disease. PMID:23959719

  11. Characterization of an autoinducer of penicillin biosynthesis in Penicillium chrysogenum.

    Science.gov (United States)

    Martín, Jorge; García-Estrada, Carlos; Rumbero, Angel; Recio, Eliseo; Albillos, Silvia M; Ullán, Ricardo V; Martín, Juan-Francisco

    2011-08-15

    Filamentous fungi produce an impressive variety of secondary metabolites; many of them have important biological activities. The biosynthesis of these secondary metabolites is frequently induced by plant-derived external elicitors and appears to also be regulated by internal inducers, which may work in a way similar to that of bacterial autoinducers. The biosynthesis of penicillin in Penicillium chrysogenum is an excellent model for studying the molecular mechanisms of control of gene expression due to a good knowledge of the biochemistry and molecular genetics of β-lactam antibiotics and to the availability of its genome sequence and proteome. In this work, we first developed a plate bioassay that allows direct testing of inducers of penicillin biosynthesis using single colonies of P. chrysogenum. Using this bioassay, we have found an inducer substance in the conditioned culture broths of P. chrysogenum and Acremonium chrysogenum. No inducing effect was exerted by γ-butyrolactones, jasmonic acid, or the penicillin precursor δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine. The conditioned broth induced penicillin biosynthesis and transcription of the pcbAB, pcbC, and penDE genes when added at inoculation time, but its effect was smaller if added at 12 h and it had no effect when added at 24 h, as shown by Northern analysis and lacZ reporter studies. The inducer molecule was purified and identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR) as 1,3-diaminopropane. Addition of pure 1,3-diaminopropane stimulated the production of penicillin by about 100% compared to results for the control cultures. Genes for the biosynthesis of 1,3-diaminopropane have been identified in the P. chrysogenum genome.

  12. 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.

  13. Inducers and autoinducers on Salmonella enterica serovar Typhimurium motility, growth and gene expression

    Directory of Open Access Journals (Sweden)

    Rita de Cássia dos Santos da Conceição

    2015-12-01

    Full Text Available Genus Salmonella bacteria are among the major pathogenic microorganisms in food. This bacterium pathogenicity is related to a number of virulence factors, among which its flagella. Flagellum expression is one of the virulence factors modulated by Quorum Sensing. Epinephrine produced by mammals uses the same signaling pathway of the 3 bacteria autoinducer. This study evaluated the effect of molecules inducer (epinephrine and autoinducers (autoinducer 2 and autoinducer 3 and their association with the motility, growth and expression genes flhC, fliA, fliY, motA, motB e fliC of Salmonella Typhimurium (ST. Initially, ST was inoculated in BHI. Then, motility assays, growth curves and gene expression were performed by testing different concentrations of epinephrine (50, 125, 250, 500µM, conditioned medium (10 and 50% and a combination of these. ST was exposed to different concentrations of epinephrine, conditioned medium and an association of both. Following, motility assays, bacterial growth and gene expression were performed. The results obtained showed that the combination of 500uM epinephrine with 50% conditioned medium increased ST bacterial motility by increasing the expression of genes involved in flagellum assembly.

  14. 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.

  15. 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 ...

  16. 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.

  17. 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%.

  18. 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...

  19. Exploring the selectivity of auto-inducer complex with LuxR using molecular docking, mutational studies and molecular dynamics simulations

    Science.gov (United States)

    Rajamanikandan, Sundaraj; Srinivasan, Pappu

    2017-03-01

    Bacteria communicate with one another using extracellular signaling molecules called auto-inducers (AHLs), a process termed as quorum sensing. The quorum sensing process allows bacteria to regulate various physiological activities. In this regard, quorum sensing master regulator LuxR from Vibrio harveyi represents an attractive therapeutic target for the development of novel anti-quorum sensing agents. Eventhough the binding of AHL complex with LuxR is evidenced in earlier reports, but their mode of binding is not clearly determined. Therefore, in the present work, molecular docking, in silico mutational studies, molecular dynamics simulations and free energy calculations were performed to understand the selectivity of AHL into the binding site of LuxR. The results revealed that Asn133 and Gln137 residues play a crucial role in recognizing AHL more effectively into the binding site of LuxR with good binding free energy. In addition to that, the carbonyl group presents in the lactone ring and amide group of AHL plays a vital role in the formation of hydrogen bond interactions with the protein. Further, structure based virtual screening was performed using ChemBridge database to screen potent lead molecules against LuxR. 4-benzyl-2-pyrrolidinone and N-[2(1-cyclohexen-1-yl) enthyl]-N'(2-ethoxyphenyl) were selected based on dock score, binding affinity and mode of interactions with the receptor. Furthermore, binding free energy, density functional theory and ADME prediction were performed to rank the lead molecules. Thus, the identified lead molecules can be used for the development of anti-quorum sensing drugs.

  20. 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.

  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. 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.

  3. Requirement for autoinducer in transcriptional negative autoregulation of the Vibrio fischeri luxR gene in Escherichia coli.

    OpenAIRE

    1989-01-01

    The effect of a mutation in luxI (autoinducer synthetase gene) on transcription of luxR in the cloned Vibrio fischeri lux system (luxR, luxICDABE) was examined in Escherichia coli. For the luxI mutant, transcription from the luxR promoter (monitored with beta-galactosidase levels from a luxR::lacZ fusion, with LuxR supplied in trans) decreased fivefold, to levels of the luxI+ strain, only in the presence of added autoinducer. The results demonstrate that, as has been shown at the translationa...

  4. 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...

  5. A Host-Produced Autoinducer-2 Mimic Activates Bacterial Quorum Sensing.

    Science.gov (United States)

    Ismail, Anisa S; Valastyan, Julie S; Bassler, Bonnie L

    2016-04-13

    Host-microbial symbioses are vital to health; nonetheless, little is known about the role crosskingdom signaling plays in these relationships. In a process called quorum sensing, bacteria communicate with one another using extracellular signal molecules called autoinducers. One autoinducer, AI-2, is proposed to promote interspecies bacterial communication, including in the mammalian gut. We show that mammalian epithelia produce an AI-2 mimic activity in response to bacteria or tight-junction disruption. This AI-2 mimic is detected by the bacterial AI-2 receptor, LuxP/LsrB, and can activate quorum-sensing-controlled gene expression, including in the enteric pathogen Salmonella typhimurium. AI-2 mimic activity is induced when epithelia are directly or indirectly exposed to bacteria, suggesting that a secreted bacterial component(s) stimulates its production. Mutagenesis revealed genes required for bacteria to both detect and stimulate production of the AI-2 mimic. These findings uncover a potential role for the mammalian AI-2 mimic in fostering crosskingdom signaling and host-bacterial symbioses.

  6. 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.

  7. Identification of poultry meat-derived fatty acids functioning as quorum sensing signal inhibitors of autoinducer-2 (AI-2)

    Science.gov (United States)

    Autoinducer-2 (AI-2) is a compound that plays a key role in bacterial cell-to-cell communication (quorum sensing). Previous research has shown certain food matrices inhibit this signaling compound. Using the reporter strain, Vibrio harveyi BB170, quorum sensing inhibitors contained in poultry meat...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. The Crystal Structure of the Escherichia coli Autoinducer-2 Processing Protein LsrF

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Z.; Xavier, K; Miller, S

    2009-01-01

    Many bacteria produce and respond to the quorum sensing signal autoinducer-2 (AI-2). Escherichia coli and Salmonella typhimurium are among the species with the lsr operon, an operon containing AI-2 transport and processing genes that are up regulated in response to AI-2. One of the Lsr proteins, LsrF, has been implicated in processing the phosphorylated form of AI-2. Here, we present the structure of LsrF, unliganded and in complex with two phospho-AI-2 analogues, ribose-5-phosphate and ribulose-5-phosphate. The crystal structure shows that LsrF is a decamer of (??)8-barrels that exhibit a previously unseen N-terminal domain swap and have high structural homology with aldolases that process phosphorylated sugars. Ligand binding sites and key catalytic residues are structurally conserved, strongly implicating LsrF as a class I aldolase.

  13. Isolation of the Autoinducer-Quenching Strain that Inhibits LasR in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Lixing Weng

    2014-04-01

    Full Text Available Quorum sensing (QS has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 µg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 µg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI and cognate receptor (lasR and rhlR genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s interferes with the las system and significantly inhibits biofilm formation.

  14. 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.

  15. 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...

  16. 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.

  17. 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...

  18. 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.

  19. 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

  20. 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].

  1. Autoinducer-2-like activity on vegetable produce and its potential involvement in bacterial biofilm formation on tomatoes.

    Science.gov (United States)

    Lu, Lingeng; Hume, Michael E; Pillai, Suresh D

    2005-01-01

    Quorum sensing employing autoinducer molecules is a strategy used by bacterial populations to coordinately modulate their response to environmental stresses and host defense mechanisms. The objectives of this study were to determine the levels of autoinducer-2 (AI-2)-like activity on selected vegetable produce and determine whether AI-2-like molecules can promote E. coli O157:H7 biofilm formation on tomatoes. Twelve different fruit and vegetable produce samples were screened for AI-2-like activity using autoinducer sensing V. harveyi biosensor strains. All samples except strawberries showed AI-2 activity albeit at varying levels, with eggplant having the highest levels. Tomatoes, when stored at 4 degrees C for 9 days, showed increasing levels of heterotrophic bacterial populations as compared to AI-2-like activity levels, which fluctuated. Rinses from Roma tomato surfaces that were stored at refrigeration temperature for up to 9 days caused a significant increase (1.8-3.6-fold as compared to the negative controls) in biofilm formation by luxS mutant (non AI-2 producing) generic E. coli and E. coli O157:H7 strains using a micro-titer plate-based biofilm assay. These results suggest that AI-2-like activity, which is present on the surfaces of tomatoes, has the potential to enhance the production of bacterial biofilms.

  2. The Vibrio cholerae quorum-sensing autoinducer CAI-1: analysis of the biosynthetic enzyme CqsA

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, R.; Bolitho, M; Higgins, D; Lu, W; Ng, W; Jeffrey, P; Rabinowitz, J; Semmelhack, M; Hughson, F; Bassler, B

    2009-01-01

    Vibrio cholerae, the bacterium that causes the disease cholera, controls virulence factor production and biofilm development in response to two extracellular quorum-sensing molecules, called autoinducers. The strongest autoinducer, called CAI-1 (for cholera autoinducer-1), was previously identified as (S)-3-hydroxytridecan-4-one. Biosynthesis of CAI-1 requires the enzyme CqsA. Here, we determine the CqsA reaction mechanism, identify the CqsA substrates as (S)-2-aminobutyrate and decanoyl coenzyme A, and demonstrate that the product of the reaction is 3-aminotridecan-4-one, dubbed amino-CAI-1. CqsA produces amino-CAI-1 by a pyridoxal phosphate-dependent acyl-CoA transferase reaction. Amino-CAI-1 is converted to CAI-1 in a subsequent step via a CqsA-independent mechanism. Consistent with this, we find cells release {ge}100 times more CAI-1 than amino-CAI-1. Nonetheless, V. cholerae responds to amino-CAI-1 as well as CAI-1, whereas other CAI-1 variants do not elicit a quorum-sensing response. Thus, both CAI-1 and amino-CAI-1 have potential as lead molecules in the development of an anticholera treatment.

  3. 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.

  4. Autoinducer-2 analogs and electric fields - an antibiotic-free bacterial biofilm combination treatment.

    Science.gov (United States)

    Subramanian, Sowmya; Gerasopoulos, Konstantinos; Guo, Min; Sintim, Herman O; Bentley, William E; Ghodssi, Reza

    2016-10-01

    Bacterial biofilms are a common cause of chronic medical implant infections. Treatment and eradication of biofilms by conventional antibiotic therapy has major drawbacks including toxicity and side effects associated with high-dosage antibiotics. Additionally, administration of high doses of antibiotics may facilitate the emergence of antibiotic resistant bacteria. Thus, there is an urgent need for the development of treatments that are not based on conventional antibiotic therapies. Presented herein is a novel bacterial biofilm combination treatment independent of traditional antibiotics, by using low electric fields in combination with small molecule inhibitors of bacterial quorum sensing - autoinducer-2 analogs. We investigate the effect of this treatment on mature Escherichia coli biofilms by application of an alternating and offset electric potential in combination with the small molecule inhibitor for 24 h using both macro and micro-scale devices. Crystal violet staining of the macro-scale biofilms shows a 46 % decrease in biomass compared to the untreated control. We demonstrate enhanced treatment efficacy of the combination therapy using a high-throughput polydimethylsiloxane-based microfluidic biofilm analysis platform. This microfluidic flow cell is designed to reduce the growth variance of in vitro biofilms while providing an integrated control, and thus allows for a more reliable comparison and evaluation of new biofilm treatments on a single device. We utilize linear array charge-coupled devices to perform real-time tracking of biomass by monitoring changes in optical density. End-point confocal microscopy measurements of biofilms treated with the autoinducer analog and electric fields in the microfluidic device show a 78 % decrease in average biofilm thickness in comparison to the negative controls and demonstrate good correlation with real-time optical density measurements. Additionally, the combination treatment showed 76 % better treatment

  5. 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.

  6. Autoinducer 2: a concentration-dependent signal for mutualistic bacterial biofilm growth

    Science.gov (United States)

    Rickard, A.H.; Palmer, R.J.; Blehert, D.S.; Campagna, S.R.; Semmelhack, M.F.; Egland, P.G.; Bassler, B.L.; Kolenbrander, P.E.

    2006-01-01

    4,5-dihydroxy-2,3-pentanedione (DPD), a product of the LuxS enzyme in the catabolism of S-ribosylhomocysteine, spontaneously cyclizes to form autoinducer 2 (AI-2). AI-2 is proposed to be a universal signal molecule mediating interspecies communication among bacteria. We show that mutualistic and abundant biofilm growth in flowing saliva of two human oral commensal bacteria, Actinomyces naeslundii T14V and Streptococcus oralis 34, is dependent upon production of AI-2 by S. oralis 34. A luxS mutant of S. oralis 34 was constructed which did not produce AI-2. Unlike wild-type dual-species biofilms, A. naeslundii T14V and an S. oralis 34 luxS mutant did not exhibit mutualism and generated only sparse biofilms which contained a 10-fold lower biomass of each species. Restoration of AI-2 levels by genetic or chemical (synthetic AI-2 in the form of DPD) complementation re-established the mutualistic growth and high biomass characteristic for the wild-type dual-species biofilm. Furthermore, an optimal concentration of DPD was determined, above and below which biofilm formation was suppressed. The optimal concentration was 100-fold lower than the detection limit of the currently accepted AI-2 assay. Thus, AI-2 acts as an interspecies signal and its concentration is critical for mutualism between two species of oral bacteria grown under conditions that are representative of the human oral cavity. ?? 2006 Blackwell Publishing Ltd.

  7. Quorum activation at a distance: spatiotemporal patterns of gene regulation from diffusion of an autoinducer signal

    Science.gov (United States)

    Dilanji, Gabriel; Langebrake, Jessica; Deleenheer, Patrick; Hagen, Stephen J.

    2012-02-01

    Bacteria in colonies coordinate gene regulation through the exchange of diffusible signal molecules known as autoinducers (AI). This ``quorum signaling'' often occurs in physically heterogeneous and spatially extended environments such as biofilms. Under these conditions the space and time scales for diffusion of the signal limit the range and timing of effective gene regulation. We expect that spatial and temporal patterns of gene expression will reflect physical environmental constraints as well as nonlinear transcriptional activation and feedback within the gene regulatory system. We have combined experiments and modeling to investigate how these spatiotemporal patterns develop. We embed engineered plasmid/GFP quorum sensor strains or wild type strains in a long narrow agar lane, and then introduce AI signal at one terminus of the lane. Diffusion of the AI initiates reporter expression along the length of the lane, extending to macroscopic distances of mm-cm. Resulting patterns are captured quantitatively by a mathematical model that incorporates logistic growth of the population, diffusion of AI, and nonlinear transcriptional activation. Our results show that a diffusing quorum signal can coordinate gene expression over distances of order 1cm on time scales of order 10 hrs.

  8. 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.

  9. Auto-inducing media for uniform isotope labeling of proteins with {sup 15}N, {sup 13}C and {sup 2}H

    Energy Technology Data Exchange (ETDEWEB)

    Guthertz, Nicolas [Institute of Cancer Research, Division of Structural Biology (United Kingdom); Klopp, Julia; Winterhalter, Aurélie; Fernández, César; Gossert, Alvar D., E-mail: alvar.gossert@novartis.com [Novartis Institutes for BioMedical Research (Switzerland)

    2015-06-15

    Auto-inducing media for protein expression offer many advantages like robust reproducibility, high yields of soluble protein and much reduced workload. Here, an auto-inducing medium for uniform isotope labelling of proteins with {sup 15}N, {sup 13}C and/or {sup 2}H in E. coli is presented. So far, auto-inducing media have not found widespread application in the NMR field, because of the prohibitively high cost of labeled lactose, which is an essential ingredient of such media. Here, we propose using lactose that is only selectively labeled on the glucose moiety. It can be synthesized from inexpensive and readily available substrates: labeled glucose and unlabeled activated galactose. With this approach, uniformly isotope labeled proteins were expressed in unattended auto-inducing cultures with incorporation of {sup 13}C, {sup 15}N of 96.6 % and {sup 2}H, {sup 15}N of 98.8 %. With the present protocol, the NMR community could profit from the many advantages that auto-inducing media offer.

  10. Selection of the N-acylhomoserine lactone-degrading bacterium Alteromonas stellipolaris PQQ-42 and of its potential for biocontrol in aquaculture

    Directory of Open Access Journals (Sweden)

    Marta eTorres

    2016-05-01

    Full Text Available The production of virulence factors by many pathogenic microorganisms depends on the intercellular communication system called quorum sensing (QS, which involves the production and release of signal molecules known as autoinducers. Based on this, new-therapeutic strategies have emerged for the treatment of a variety of infections, such as the enzymatic degradation of signalling molecules, known as quorum quenching (QQ. In this study, we present the screening of QQ activity amongst 450 strains isolated from a bivalve hatchery in Granada (Spain, and the selection of the strain PQQ-42, which degrades a wide range of N-acylhomoserine lactones (AHLs. The selected strain, identified as Alteromonas stellipolaris, degraded the accumulation of AHLs and reduced the production of protease and chitinase and swimming motility of a Vibrio species in co-cultivation experiments in vitro. In the bio-control experiment, strain PQQ-42 significantly reduced the pathogenicity of V. mediterranei VibC-Oc-097 upon the coral Oculina patagonica showing a lower degree of tissue damage (29.25±14.63 % in its presence, compared to when the coral was infected with V. mediterranei VibC-Oc-097 alone (77.53±13.22 %. Our results suggest that this AHL-degrading bacterium may have biotechnological applications in aquaculture.

  11. 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).

  12. 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...

  13. Staphylococcus aureus autoinducer-2 quorum sensing decreases biofilm formation in an icaR-dependent manner

    Directory of Open Access Journals (Sweden)

    Yu Dan

    2012-12-01

    Full Text Available Abstract Background Staphylococcus aureus is an important pathogen that causes biofilm-associated infection in humans. Autoinducer 2 (AI-2, a quorum-sensing (QS signal for interspecies communication, has a wide range of regulatory functions in both Gram-positive and Gram-negative bacteria, but its exact role in biofilm formation in S. aureus remains unclear. Results Here we demonstrate that mutation of the AI-2 synthase gene luxS in S. aureus RN6390B results in increased biofilm formation compared with the wild-type (WT strain under static, flowing and anaerobic conditions and in a mouse model. Addition of the chemically synthesized AI-2 precursor in the luxS mutation strain (ΔluxS restored the WT phenotype. Real-time RT-PCR analysis showed that AI-2 activated the transcription of icaR, a repressor of the ica operon, and subsequently a decreased level of icaA transcription, which was presumably the main reason why luxS mutation influences biofilm formation. Furthermore, we compared the roles of the agr-mediated QS system and the LuxS/AI-2 QS system in the regulation of biofilm formation using the ΔluxS strain, RN6911 and the Δagr ΔluxS strain. Our data indicate a cumulative effect of the two QS systems on the regulation of biofilm formation in S. aureus. Conclusion These findings demonstrate that AI-2 can decrease biofilm formation in S. aureus via an icaR-activation pathway. This study may provide clues for therapy in S. aureus biofilm-associated infection.

  14. Processing the Interspecies Quorum-sensing Signal Autoinducer-2 (AI-2)

    Energy Technology Data Exchange (ETDEWEB)

    J Marques; P Lamosa; C Russell; R Ventura; C Maycock; M Semmelhack; S Miller; K Xavier

    2011-12-31

    The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is the precursor of the signal molecule autoinducer-2 (AI-2). AI-2 mediates interspecies communication and facilitates regulation of bacterial behaviors such as biofilm formation and virulence. A variety of bacterial species have the ability to sequester and process the AI-2 present in their environment, thereby interfering with the cell-cell communication of other bacteria. This process involves the AI-2-regulated lsr operon, comprised of the Lsr transport system that facilitates uptake of the signal, a kinase that phosphorylates the signal to phospho-DPD (P-DPD), and enzymes (like LsrG) that are responsible for processing the phosphorylated signal. Because P-DPD is the intracellular inducer of the lsr operon, enzymes involved in P-DPD processing impact the levels of Lsr expression. Here we show that LsrG catalyzes isomerization of P-DPD into 3,4,4-trihydroxy-2-pentanone-5-phosphate. We present the crystal structure of LsrG, identify potential catalytic residues, and determine which of these residues affects P-DPD processing in vivo and in vitro. We also show that an lsrG deletion mutant accumulates at least 10 times more P-DPD than wild type cells. Consistent with this result, we find that the lsrG mutant has increased expression of the lsr operon and an altered profile of AI-2 accumulation and removal. Understanding of the biochemical mechanisms employed by bacteria to quench signaling of other species can be of great utility in the development of therapies to control bacterial behavior.

  15. D-Galactose as an autoinducer 2 inhibitor to control the biofilm formation of periodontopathogens.

    Science.gov (United States)

    Ryu, Eun-Ju; Sim, Jaehyun; Sim, Jun; Lee, Julian; Choi, Bong-Kyu

    2016-09-01

    Autoinducer 2 (AI-2) is a quorum sensing molecule to which bacteria respond to regulate various phenotypes, including virulence and biofilm formation. AI-2 plays an important role in the formation of a subgingival biofilm composed mostly of Gram-negative anaerobes, by which periodontitis is initiated. The aim of this study was to evaluate D-galactose as an inhibitor of AI-2 activity and thus of the biofilm formation of periodontopathogens. In a search for an AI-2 receptor of Fusobacterium nucleatum, D-galactose binding protein (Gbp, Gene ID FN1165) showed high sequence similarity with the ribose binding protein (RbsB), a known AI-2 receptor of Aggregatibacter actinomycetemcomitans. D-Galactose was evaluated for its inhibitory effect on the AI-2 activity of Vibrio harveyi BB152 and F. nucleatum, the major coaggregation bridge organism, which connects early colonizing commensals and late pathogenic colonizers in dental biofilms. The inhibitory effect of D-galactose on the biofilm formation of periodontopathogens was assessed by crystal violet staining and confocal laser scanning microscopy in the absence or presence of AI-2 and secreted molecules of F. nucleatum. D-Galactose significantly inhibited the AI-2 activity of V. harveyi and F. nucleatum. In addition, D-galactose markedly inhibited the biofilm formation of F. nucleatum, Porphyromonas gingivalis, and Tannerella forsythia induced by the AI-2 of F. nucleatum without affecting bacterial growth. Our results demonstrate that the Gbp may function as an AI-2 receptor and that galactose may be used for prevention of the biofilm formation of periodontopathogens by targeting AI-2 activity.

  16. Expression of tropodithietic acid biosynthesis is controlled by a novel autoinducer.

    Science.gov (United States)

    Geng, Haifeng; Belas, Robert

    2010-09-01

    The interactions between marine prokaryotic and eukaryotic microorganisms are crucial to many biological and biogeochemical processes in the oceans. Often the interactions are mutualistic, as in the symbiosis between phytoplankton, e.g., the dinoflagellate Pfiesteria piscicida and Silicibacter sp. TM1040, a member of the Roseobacter taxonomic lineage. It is hypothesized that an important component of this symbiosis is bacterial production of tropodithietic acid (TDA), a biologically active tropolone compound whose synthesis requires the expression of tdaABCDEF (tdaA-F), as well as six additional genes (cysI, malY, paaIJK, and tdaH). The factors controlling tda gene expression are not known, although growth in laboratory standing liquid cultures drastically increases TDA levels. In this report, we measured the transcription of tda genes to gain a greater understanding of the factors controlling their expression. While the expression of tdaAB was constitutive, tdaCDE and tdaF mRNA increased significantly (3.7- and 17.4-fold, respectively) when cells were grown in standing liquid broth compared to their levels with shaking liquid culturing. No transcription of tdaC was detected when a tdaCp::lacZ transcriptional fusion was placed in 11 of the 12 Tda(-) mutant backgrounds, with cysI being the sole exception. The expression of tdaC could be restored to 9 of the remaining 11 Tda(-) mutants-tdaA and tdaH failed to respond-by placing wild-type (Tda(+)) strains in close proximity or by supplying exogenous TDA to the mutant, suggesting that TDA induces tda gene expression. These results indicate that TDA acts as an autoinducer of its own synthesis and suggest that roseobacters may use TDA as a quorum signal.

  17. Fatty acid modulation of autoinducer (AI-2) influenced growth and macrophage invasion by Salmonella Typhimurium.

    Science.gov (United States)

    Widmer, Kenneth W; Jesudhasan, Palmy; Pillai, Suresh D

    2012-03-01

    Autoinducer-2 (AI-2) is a small molecule that is involved in bacterial cell-to-cell signaling whose precursor formation is mediated by luxS. A luxS mutant of Salmonella Typhimurium PJ002 (ΔluxS) was grown in glucose-containing M-9 minimal medium supplemented with varying concentrations (1×, 10×, and 100×) of long-chain fatty acids (linoleic acid, oleic acid, palmitic acid, and stearic acid) to study the influence of fatty acids on growth rate and macrophage invasion. Additionally, in vitro synthesized AI-2 was added to this medium to identify the influence of AI-2 on S. Typhimurium PJ002 (ΔluxS) growth rate and macrophage invasion. The growth rate constant (k) for each experimental treatment was determined based on OD₆₀₀ values recorded during 12 h of incubation. There was a significant (p=0.01) increase in the growth rate of S. Typhimurium PJ002 (ΔluxS) in the presence of AI-2 when compared to the phosphate-buffered saline (PBS) control. However, fatty acids either singly or in a mixture were unable to influence AI-2's effect on growth rate. The presence of AI-2 significantly (p=0.02) decreased the invasiveness of S. Typhimurium PJ002 (ΔluxS) towards the murine macrophage cell line, RAW 264.7. However, the fatty acid mixture was able to reverse this reduction and restore invasiveness to background levels. These results suggest that, while AI-2 may enhance the growth rate and reduce macrophage invasion by the luxS mutant S. Typhimurium PJ002 (ΔluxS), fatty acids may influence the virulence in S. Typhimurium (PJ002) by modulating AI-2 activity.

  18. 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)

  19. Characterisation of Non-Autoinducing Tropodithietic Acid (TDA) Production from Marine Sponge Pseudovibrio Species

    DEFF Research Database (Denmark)

    Harrington, Catriona; Reen, F. Jerry; Mooij, Marlies J.;

    2014-01-01

    is the antibacterial compound tropodithietic acid (TDA). The aim of this study was to provide insight into the bioactivity of and the factors governing the production of TDA in marine Pseudovibrio isolates from a collection of marine sponges. The TDA produced by these Pseudovibrio isolates exhibited potent...... antimicrobial activity against a broad spectrum of clinical pathogens, while TDA tolerance was frequent in non-TDA producing marine isolates. Comparative genomics analysis suggested a high degree of conservation among the tda biosynthetic clusters while expression studies revealed coordinated regulation of TDA...... synthesis upon transition from log to stationary phase growth, which was not induced by TDA itself or by the presence of the C10-acyl homoserine lactone quorum sensing signal molecule....

  20. 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.

  1. Autoinducer 2 Signaling via the Phosphotransferase FruA Drives Galactose Utilization by Streptococcus pneumoniae, Resulting in Hypervirulence

    Science.gov (United States)

    McAllister, Lauren J.; Chen, Austen; Wang, Hui; Paton, Adrienne W.; Oggioni, Marco R.; McDevitt, Christopher A.

    2017-01-01

    ABSTRACT Communication between bacterial cells is crucial for the coordination of diverse cellular processes that facilitate environmental adaptation and, in the case of pathogenic species, virulence. This is achieved by the secretion and detection of small signaling molecules called autoinducers, a process termed quorum sensing. To date, the only signaling molecule recognized by both Gram-positive and Gram-negative bacteria is autoinducer 2 (AI-2), synthesized by the metabolic enzyme LuxS (S-ribosylhomocysteine lyase) as a by-product of the activated methyl cycle. Homologues of LuxS are ubiquitous in bacteria, suggesting a key role in interspecies, as well as intraspecies, communication. Gram-negative bacteria sense and respond to AI-2 via the Lsr ABC transporter system or by the LuxP/LuxQ phosphorelay system. However, homologues of these systems are absent from Gram-positive bacteria and the AI-2 receptor is unknown. Here we show that in the major human pathogen Streptococcus pneumoniae, sensing of exogenous AI-2 is dependent on FruA, a fructose-specific phosphoenolpyruvate-phosphotransferase system that is highly conserved in Gram-positive pathogens. Importantly, AI-2 signaling via FruA enables the bacterium to utilize galactose as a carbon source and upregulates the Leloir pathway, thereby leading to increased production of capsular polysaccharide and a hypervirulent phenotype. PMID:28119473

  2. Autoinducer-2 increases biofilm formation via an ica- and bhp-dependent manner in Staphylococcus epidermidis RP62A.

    Science.gov (United States)

    Xue, Ting; Ni, Jingtian; Shang, Fei; Chen, Xiaolin; Zhang, Ming

    2015-05-01

    Staphylococcus epidermidis has become the most common cause of nosocomial bacteraemia and the principal organism responsible for indwelling medical device -associated infections. Its pathogenicity is mainly due to its ability to form biofilms on the implanted medical devices. Biofilm formation is a quorum-sensing (QS)-dependent process controlled by autoinducers, which are signalling molecules. Here, we investigated the function of the autoinducer-2 (AI-2) QS system, especially the influence of AI-2 on biofilm formation in S. epidermidis RP62A. Results showed that the addition of AI-2 leads to a significant increase in biofilm formation, in contrast with previous studies which showed that AI-2 limits biofilm formation in Staphylococci. We found that AI-2 increases biofilm formation by enhancing the transcription of the ica operon, which is a known component in the AI-2-regulated biofilm pathway. In addition, we first observed that the transcript level of bhp, which encodes a biofilm-associated protein, was also increased following the addition of AI-2. Furthermore, we found that, among the known biofilm regulator genes (icaR, sigB, rbsU, sarA, sarX, sarZ, clpP, agrA, abfR, arlRS, saeRS), only icaR can be regulated by AI-2, suggesting that AI-2 may regulate biofilm formation by an icaR-dependent mechanism in S. epidermidis RP62A.

  3. Autoinducer-2 influences interactions amongst pioneer colonizing streptococci in oral biofilms.

    Science.gov (United States)

    Cuadra-Saenz, Giancarlo; Rao, Dhana L; Underwood, Adam J; Belapure, Sneha A; Campagna, Shawn R; Sun, Zhichao; Tammariello, Steven; Rickard, Alexander H

    2012-07-01

    Streptococcus gordonii and Streptococcus oralis are among the first bacterial species to colonize clean tooth surfaces. Both produce autoinducer-2 (AI-2): a family of inter-convertible cell-cell signal molecules synthesized by the LuxS enzyme. The overall aim of this work was to determine whether AI-2 alters interspecies interactions between S. gordonii DL1 and S. oralis 34 within dual-species biofilms in flowing human saliva. Based upon AI-2 bioluminescence assays, S. gordonii DL1 produced more AI-2 activity than S. oralis 34 in batch culture, and both were able to remove AI-2 activity from solution. In single-species, saliva-fed flowcell systems, S. oralis 34 formed scant biofilms that were similar to the luxS mutant. Conversely, S. gordonii DL1 formed confluent biofilms while the luxS mutant formed architecturally distinct biofilms that possessed twofold greater biovolume than the wild-type. Supplementing saliva with 0.1-10 nM chemically synthesized AI-2 (csAI-2) restored the S. gordonii DL1 luxS biofilm phenotype to that which was similar to the wild-type; above or below this concentration range, biofilms were architecturally similar to that formed by the luxS mutant. In dual-species biofilms, S. gordonii DL1 was always more abundant than S. oralis 34. Compared with dual-species, wild-type biofilms, the biovolume occupied by S. oralis 34 was reduced by greater than sevenfold when neither species produced AI-2. The addition of 1 nM csAI-2 to the dual-species luxS-luxS mutant biofilms re-established the biofilm phenotype to resemble that of the wild-type pair. Thus, this work demonstrates that AI-2 can alter the biofilm structure and composition of pioneering oral streptococcal biofilms. This may influence the subsequent succession of other species into oral biofilms and the ecology of dental plaque.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. Protonation and lactonization of {alpha}-iso-saccharinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rao, L.; Tian, G. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Zhang, Z. [Washington State University, Pullman, WA 99165 (United States); Rai, D. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2005-07-01

    Full text of publication follows: {alpha}-iso-saccharinic acid, a degradation product of cellulose materials, has been a subject of study due to its ability to complex actinides and affect their migration behavior in the environment. Like other poly-hydroxy-carboxylic acids such as gluconic acid, {alpha}-iso-saccharinic acid undergoes dehydration to form {alpha}-iso-saccharinate-1,4-lactone in acidic solutions. The lactonization of iso-saccharinic acid is slower than the protonation/deprotonation reactions because it involves breaking and formation of C-O as well as O-H bonds. It is important to take into consideration the slow lactonization reaction when determining the protonation constant of iso-saccharinic acid. In this work, the protonation of a-iso-saccharinate and the lactonization of {alpha}-iso-saccharinic acid have been evaluated by potentiometry. A concept of 'composite' protonation constant, similar to the well-known composite protonation constant of carbonic acid [1], is developed for {alpha}- iso-saccharinic acid. Results on the protonation and lactonization of {alpha}-iso-saccharinic acid are discussed in comparison with gluconic acid. This research was supported by the Office of Science, Office of Basic Energy Sciences and Office of Biological and Environmental Research, U.S. Department of Energy, under Contract No. DE-AC03-76SF0098 at Lawrence Berkeley National Laboratory. [1] Stumm, W., Morgan, J.J.: 'Aquatic Chemistry: an Introduction Emphasizing Chemical Equilibria in Natural Waters', John Wiley and Sons, New York (1981), pp. 173-174. (authors)

  13. Characterisation of non-autoinducing tropodithietic Acid (TDA) production from marine sponge Pseudovibrio species.

    Science.gov (United States)

    Harrington, Catriona; Reen, F Jerry; Mooij, Marlies J; Stewart, Fiona A; Chabot, Jean-Baptiste; Guerra, Antonio F; Glöckner, Frank O; Nielsen, Kristian F; Gram, Lone; Dobson, Alan D W; Adams, Claire; O'Gara, Fergal

    2014-12-10

    The search for new antimicrobial compounds has gained added momentum in recent years, paralleled by the exponential rise in resistance to most known classes of current antibiotics. While modifications of existing drugs have brought some limited clinical success, there remains a critical need for new classes of antimicrobial compound to which key clinical pathogens will be naive. This has provided the context and impetus to marine biodiscovery programmes that seek to isolate and characterize new activities from the aquatic ecosystem. One new antibiotic to emerge from these initiatives is the antibacterial compound tropodithietic acid (TDA). The aim of this study was to provide insight into the bioactivity of and the factors governing the production of TDA in marine Pseudovibrio isolates from a collection of marine sponges. The TDA produced by these Pseudovibrio isolates exhibited potent antimicrobial activity against a broad spectrum of clinical pathogens, while TDA tolerance was frequent in non-TDA producing marine isolates. Comparative genomics analysis suggested a high degree of conservation among the tda biosynthetic clusters while expression studies revealed coordinated regulation of TDA synthesis upon transition from log to stationary phase growth, which was not induced by TDA itself or by the presence of the C10-acyl homoserine lactone quorum sensing signal molecule.

  14. Characterisation of Non-Autoinducing Tropodithietic Acid (TDA Production from Marine Sponge Pseudovibrio Species

    Directory of Open Access Journals (Sweden)

    Catriona Harrington

    2014-12-01

    Full Text Available The search for new antimicrobial compounds has gained added momentum in recent years, paralleled by the exponential rise in resistance to most known classes of current antibiotics. While modifications of existing drugs have brought some limited clinical success, there remains a critical need for new classes of antimicrobial compound to which key clinical pathogens will be naive. This has provided the context and impetus to marine biodiscovery programmes that seek to isolate and characterize new activities from the aquatic ecosystem. One new antibiotic to emerge from these initiatives is the antibacterial compound tropodithietic acid (TDA. The aim of this study was to provide insight into the bioactivity of and the factors governing the production of TDA in marine Pseudovibrio isolates from a collection of marine sponges. The TDA produced by these Pseudovibrio isolates exhibited potent antimicrobial activity against a broad spectrum of clinical pathogens, while TDA tolerance was frequent in non-TDA producing marine isolates. Comparative genomics analysis suggested a high degree of conservation among the tda biosynthetic clusters while expression studies revealed coordinated regulation of TDA synthesis upon transition from log to stationary phase growth, which was not induced by TDA itself or by the presence of the C10-acyl homoserine lactone quorum sensing signal molecule.

  15. New Insights into Autoinducer-2 Signaling as a Virulence Regulator in a Mouse Model of Pneumonic Plague

    Science.gov (United States)

    Fitts, Eric C.; Andersson, Jourdan A.; Kirtley, Michelle L.; Sha, Jian; Erova, Tatiana E.; Chauhan, Sadhana; Motin, Vladimir L.

    2016-01-01

    ABSTRACT The Enterobacteriaceae family members, including the infamous Yersinia pestis, the causative agent of plague, have a highly conserved interbacterial signaling system that is mediated by the autoinducer-2 (AI-2) quorum-sensing molecule. The AI-2 system is implicated in regulating various bacterial virulence genes in diverse environmental niches. Deletion of the gene encoding the synthetic enzyme for the AI-2 substrate, luxS, leads to either no significant change or, paradoxically, an increase in in vivo bacterial virulence. We showed that deletion of the rbsA and lsrA genes, components of ABC transport systems that interact with AI-2, synergistically disrupted AI-2 signaling patterns and resulted in a more-than-50-fold decrease in Y. pestis strain CO92 virulence in a stringent pneumonic plague mouse model. Deletion of luxS or lsrK (encoding AI-2 kinase) from the ΔrbsA ΔlsrA background strain or complementation of the ΔrbsA ΔlsrA mutant with the corresponding gene(s) reverted the virulence phenotype to that of the wild-type Y. pestis CO92. Furthermore, the administration of synthetic AI-2 in mice infected with the ΔrbsA ΔlsrA ΔluxS mutant strain attenuated this triple mutant to a virulence phenotype similar to that of the ΔrbsA ΔlsrA strain in a pneumonic plague model. Conversely, the administration of AI-2 to mice infected with the ΔrbsA ΔlsrA ΔluxS ΔlsrK mutant did not rescue animals from lethality, indicating the importance of the AI-2–LsrK axis in regulating bacterial virulence. By performing high-throughput RNA sequencing, the potential role of some AI-2-signaling-regulated genes that modulated bacterial virulence was determined. We anticipate that the characterization of AI-2 signaling in Y. pestis will lead to reexamination of AI-2 systems in other pathogens and that AI-2 signaling may represent a broad-spectrum therapeutic target to combat antibiotic-resistant bacteria, which represent a global crisis of the 21st century. IMPORTANCE

  16. 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....

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. [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).

  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. 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

  12. Autoinducer-2 plays a crucial role in gut colonization and probiotic functionality of Bifidobacterium breve UCC2003.

    Directory of Open Access Journals (Sweden)

    Steven E A Christiaen

    Full Text Available In the present study we show that luxS of Bifidobacterium breve UCC2003 is involved in the production of the interspecies signaling molecule autoinducer-2 (AI-2, and that this gene is essential for gastrointestinal colonization of a murine host, while it is also involved in providing protection against Salmonella infection in Caenorhabditis elegans. We demonstrate that a B. breve luxS-insertion mutant is significantly more susceptible to iron chelators than the WT strain and that this sensitivity can be partially reverted in the presence of the AI-2 precursor DPD. Furthermore, we show that several genes of an iron starvation-induced gene cluster, which are downregulated in the luxS-insertion mutant and which encodes a presumed iron-uptake system, are transcriptionally upregulated under in vivo conditions. Mutation of two genes of this cluster in B. breve UCC2003 renders the derived mutant strains sensitive to iron chelators while deficient in their ability to confer gut pathogen protection to Salmonella-infected nematodes. Since a functional luxS gene is present in all tested members of the genus Bifidobacterium, we conclude that bifidobacteria operate a LuxS-mediated system for gut colonization and pathogen protection that is correlated with iron acquisition.

  13. Role of acetate in production of an autoinducible Class IIa Bacteriocin in Carnobacterium piscicola A9b

    DEFF Research Database (Denmark)

    Nilsson, Lilian; Nielsen, Michael Krogsgaard; Ng, Yin;

    2002-01-01

    was to purify the compound and describe factors affecting its production, with particular emphasis on food-relevant factors. Amino acid sequencing showed that the compound is a class IIa bacteriocin with an N-terminal amino acid sequence identical to that of carnobacteriocin B2. The production...... of the bacteriocin was autoinducible, and the threshold level for induction was 9.6 x 10(-10) M. We also report, for the first time, that acetate acts as an induction factor, with a threshold concentration of 0.3 to 12 mM. Acetate could not act as an inducer during the late exponential phase of C. piscicola A9b....... The induction of bacteriocin production showed a dose-dependent relationship at acetate concentrations of up to 10 to 20 mM (depending on the growth medium) and at a concentration of 1.9 x 10(-8) M for the bacteriocin itself; a saturation level of bacteriocin specific activity was reached...

  14. Production of autoinducer-2 by aerobic endospore-forming bacteria isolated from the West African fermented foods.

    Science.gov (United States)

    Qian, Yang; Kando, Christine Kere; Thorsen, Line; Larsen, Nadja; Jespersen, Lene

    2015-11-01

    Autoinducer-2 (AI-2) is a quorum-sensing (QS) molecule which mediates interspecies signaling and affects various bacterial behaviors in food fermentation. Biosynthesis of AI-2 is controlled by S-ribosylhomocysteine lyase encoded by the luxS gene. The objective of this study was to investigate production of AI-2 by aerobic endospore-forming bacteria (AEB) isolated from the West African alkaline fermented seed products Mantchoua and Maari. The study included 13 AEB strains of Bacillus subtilis, B. cereus, B. altitudinis, B. amyloliquefaciens, B. licheniformis, B. aryabhattai, B. safensis, Lysinibacillus macroides and Paenibacillus polymyxa. All the tested strains harbored the luxS gene and all strains except for P. polymyxa B314 were able to produce AI-2 during incubation in laboratory medium. Production of AI-2 by AEB was growth phase dependent, showing maximum activity at the late exponential phase. AI-2 was depleted from the culture medium at the beginning of the stationary growth phase, indicating that the tested AEB possess a functional AI-2 receptor that internalizes AI-2. This study provides the evidences of QS system in Bacillus spp. and L. macroides and new knowledge of AI-2 production by AEB. This knowledge contributes to the development of QS-based strategies for better control of alkaline fermentation.

  15. Identification of poultry meat-derived fatty acids functioning as quorum sensing signal inhibitors to autoinducer-2 (AI-2).

    Science.gov (United States)

    Widmer, K W; Soni, K A; Hume, M E; Beier, R C; Jesudhasan, P; Pillai, S D

    2007-11-01

    Autoinducer-2 (AI-2) is a compound that plays a key role in bacterial cell-to-cell communication (quorum sensing). Previous research has shown certain food matrices inhibit this signaling compound. Using the reporter strain, Vibrio harveyi BB170, quorum-sensing inhibitors contained in poultry meat wash (PMW) samples were characterized by molecular weight and hydrophobic properties using liquid chromatography systems. Most fractions that demonstrated AI-2 inhibition were 13.7 kDa or less, and had hydrophobic properties. Hexane was used to extract inhibitory compounds from a PMW preparation and the extract was further separated by gas chromatography (GC). Several fatty acids were identified and quantified. Linoleic acid, oleic acid, palmitic acid, and stearic acid were each tested for inhibition at 0.1, 1, and 10 mM concentrations. All samples expressed AI-2 inhibition (ranging from approximately 25% to 99%). Fatty acids, combined in concentrations equivalent to those determined by GC analysis, expressed inhibition at 59.5%, but higher combined concentrations (10- and 100-fold) had inhibition at 84.4% and 69.5%, respectively. The combined fatty acids (100-fold) did not demonstrate a substantial decrease in colony plate counts, despite presenting high AI-2 inhibition. These fatty acids, through modulating quorum sensing by inhibition, may offer a unique means to control foodborne pathogens and reduce microbial spoilage.

  16. 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.

  17. 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.

  18. 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.

  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. 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

  1. 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.

  2. 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.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. The new pLAI (lux regulon based auto-inducible expression system for recombinant protein production in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Nocadello Salvatore

    2012-01-01

    Full Text Available Abstract Background After many years of intensive research, it is generally assumed that no universal expression system can exist for high-level production of a given recombinant protein. Among the different expression systems, the inducible systems are the most popular for their tight regulation. However, induction is in many cases less favorable due to the high cost and/or toxicity of inducers, incompatibilities with industrial scale-up or detrimental growth conditions. Expression systems using autoinduction (or self-induction prove to be extremely versatile allowing growth and induction of recombinant proteins without the need to monitor cell density or add inducer. Unfortunately, almost all the actual auto inducible expression systems need endogenous or induced metabolic changes during the growth to trigger induction, both frequently linked to detrimental condition to cell growth. In this context, we use a simple modular approach for a cell density-based genetic regulation in order to assemble an autoinducible recombinant protein expression system in E. coli. Result The newly designed pLAI expression system places the expression of recombinant proteins in Escherichia coli under control of the regulatory genes of the lux regulon of Vibrio fischeri's Quorum Sensing (QS system. The pLAI system allows a tight regulation of the recombinant gene allowing a negligible basal expression and expression only at high cell density. Sequence optimization of regulative genes of QS of V. fischeri for expression in E. coli upgraded the system to high level expression. Moreover, partition of regulative genes between the plasmid and the host genome and introduction of a molecular safety lock permitted tighter control of gene expression. Conclusion Coupling gene expression to cell density using cell-to-cell communication provides a promising approach for recombinant protein production. The system allows the control of expression of the target recombinant gene

  6. The stress-related, rhizobial small RNA RcsR1 destabilizes the autoinducer synthase encoding mRNA sinI in Sinorhizobium meliloti.

    Science.gov (United States)

    Baumgardt, Kathrin; Šmídová, Klára; Rahn, Helen; Lochnit, Günter; Robledo, Marta; Evguenieva-Hackenberg, Elena

    2016-05-03

    Quorum sensing is a cell density-dependent communication system of bacteria relying on autoinducer molecules. During the analysis of the post-transcriptional regulation of quorum sensing in the nitrogen fixing plant symbiont Sinorhizobium meliloti, we predicted and verified a direct interaction between the 5'-UTR of sinI mRNA encoding the autoinducer synthase and a small RNA (sRNA), which we named RcsR1. In vitro, RcsR1 prevented cleavage in the 5'-UTR of sinI by RNase E and impaired sinI translation. In line with low ribosomal occupancy and transcript destabilization upon binding of RcsR1 to sinI, overproduction of RcsR1 in S. meliloti resulted in lower level and shorter half-life of sinI mRNA, and in decreased autoinducer amount. Although RcsR1 can influence quorum sensing via sinI, its level did not vary at different cell densities, but decreased under salt stress and increased at low temperature. We found that RcsR1 and its stress-related expression pattern, but not the interaction with sinI homologs, are conserved in Sinorhizobium, Rhizobium and Agrobacterium. Consistently, overproduction of RcsR1 in S. meliloti and Agrobacterium tumefaciens inhibited growth at high salinity. We identified conserved targets of RcsR1 and showed that most conserved interactions and the effect on growth under salt stress are mediated by the first stem-loop of RcsR1, while its central part is responsible for the species-specific interaction with sinI. We conclude that RcsR1 is an ancient, stress-related riboregulator in rhizobia and propose that it links stress responses to quorum sensing in S. meliloti.

  7. Structural Characterization of Native Autoinducing Peptides and Abiotic Analogs Reveals Key Features Essential for Activation and Inhibition of an AgrC Quorum Sensing Receptor in Staphylococcus aureus

    OpenAIRE

    Tal-Gan, Yftah; Ivancic, Monika; Cornilescu, Gabriel; Cornilescu, Claudia C.; Blackwell, Helen E.

    2013-01-01

    Staphylococcus aureus is a major human pathogen that uses quorum sensing (QS) to control virulence. Its QS system is regulated by macrocyclic peptide signals (or autoinducing peptides (AIPs)) and their cognate transmembrane receptors (AgrCs). Four different specificity groups of S. aureus have been identified to date (groups I–IV), each of which uses a different AIP:AgrC pair. Non-native ligands capable of intercepting AIP:AgrC binding, and thereby QS, in S. aureus have attracted considerable...

  8. Quorum sensing in Aeromonas salmonicida subsp. achromogenes and the effect of the autoinducer synthase AsaI on bacterial virulence

    DEFF Research Database (Denmark)

    Schwenteit, Johanna; Gram, Lone; Nielsen, Kristian Fog;

    2011-01-01

    The Gram-negative fish pathogenic bacterium Aeromonas salmonicida possesses the LuxIRtype quorum sensing (QS) system, termed AsaIR. In this study the role of QS in A. salmonicida subsp. achromogenes virulence and pigment production was investigated. Five wild-type Asa strains induced the N......-acyl-homoserinelactone (AHL) monitor bacteria. HPLC–HR-MS analysis identified only one type of AHL, N-butanoyl-L-homoserine lactone (C4-HSL). A knock out mutant of AsaI, constructed by allelic exchange, did not produce a detectable QS signal and its virulence in fish was significantly impaired, as LD50 of the Asa...... an important virulence factor, AsaP1, without affecting bacterial growth, makes A. salmonicida subsp. achromogenes an interesting target organism to study the effects of QS in disease development and QSI in disease control....

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Short communication: The role of autoinducer 2 (AI-2) on antibiotic resistance regulation in an Escherichia coli strain isolated from a dairy cow with mastitis.

    Science.gov (United States)

    Xue, Ting; Yu, Lumin; Shang, Fei; Li, Wenchang; Zhang, Ming; Ni, Jingtian; Chen, Xiaolin

    2016-06-01

    Extended spectrum β-lactamase (ESBL)-positive Escherichia coli is a major etiological organism responsible for bovine mastitis. The autoinducer 2 (AI-2) quorum sensing system is widely present in many species of gram-negative and gram-positive bacteria and has been proposed to be involved in interspecies communication. In E. coli model strains, the functional mechanisms of AI-2 have been well studied; however, in clinical antibiotic-resistant E. coli strains, whether AI-2 affects the expression of antibiotic resistance genes has not been reported. In this study, we report that exogenous AI-2 increased the antibiotic resistance of a clinical E. coli strain isolated from a dairy cow with mastitis by upregulating the expression of TEM-type enzyme in an LsrR (LuxS regulated repressor)-dependent manner.

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  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

    samples were further characterized by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HR-MS). AHLs were produced by all strains of Aeromonas salmonicida, Aeromonas hydrophila, Yersinia ruckeri, Vibrio salmonicida, and Vibrio vulnificus. Some strains of atypical Aeromonas...... 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...

  3. 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.

  4. 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.

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

    Science.gov (United States)

    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.

  6. 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 ...

  7. 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

  8. 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

  9. Is autoinducer-2 a universal signal for interspecies communication: a comparative genomic and phylogenetic analysis of the synthesis and signal transduction pathways

    Directory of Open Access Journals (Sweden)

    Wagner-Döbler Irene

    2004-09-01

    Full Text Available Abstract Background Quorum sensing is a process of bacterial cell-to-cell communication involving the production and detection of extracellular signaling molecules called autoinducers. Recently, it has been proposed that autoinducer-2 (AI-2, a furanosyl borate diester derived from the recycling of S-adenosyl-homocysteine (SAH to homocysteine, serves as a universal signal for interspecies communication. Results In this study, 138 completed genomes were examined for the genes involved in the synthesis and detection of AI-2. Except for some symbionts and parasites, all organisms have a pathway to recycle SAH, either using a two-step enzymatic conversion by the Pfs and LuxS enzymes or a one-step conversion using SAH-hydrolase (SahH. 51 organisms including most Gamma-, Beta-, and Epsilonproteobacteria, and Firmicutes possess the Pfs-LuxS pathway, while Archaea, Eukarya, Alphaproteobacteria, Actinobacteria and Cyanobacteria prefer the SahH pathway. In all 138 organisms, only the three Vibrio strains had strong, bidirectional matches to the periplasmic AI-2 binding protein LuxP and the central signal relay protein LuxU. The initial two-component sensor kinase protein LuxQ, and the terminal response regulator luxO are found in most Proteobacteria, as well as in some Firmicutes, often in several copies. Conclusions The genomic analysis indicates that the LuxS enzyme required for AI-2 synthesis is widespread in bacteria, while the periplasmic binding protein LuxP is only present in Vibrio strains. Thus, other organisms may either use components different from the AI-2 signal transduction system of Vibrio strains to sense the signal of AI-2, or they do not have such a quorum sensing system at all.

  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. 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.

  12. 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...

  13. [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.

  14. 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.

  15. 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.

  16. The effect of environmental conditions on biofilm formation of Burkholderia pseudomallei clinical isolates.

    Directory of Open Access Journals (Sweden)

    Nur Siti K Ramli

    Full Text Available Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs and small colony variants (SCVs morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30 °C, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37 °C. In addition, octanoyl-homoserine lactone (C(8-HSL, a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C(10-HSL and dodecanoyl-homoserine lactone (C(12-HSL were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation.

  17. 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...

  18. 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...

  19. 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.

  20. 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...

  1. 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...

  2. 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.

  3. 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

  4. 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 (...

  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. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. N-Methyl and peptoid scans of an autoinducing peptide reveal new structural features required for inhibition and activation of AgrC quorum sensing receptors in Staphylococcus aureus.

    Science.gov (United States)

    Tal-Gan, Yftah; Stacy, Danielle M; Blackwell, Helen E

    2014-03-21

    We report the first N-methyl and peptoid residue scans of a full-length autoinducing peptide (AIP), AIP-III, used by Staphylococcus aureus for quorum sensing (QS). Biological evaluation of these AIP-III analogues uncovered new features of the AIP-III scaffold that can be tuned to develop chemical probes of QS in all four groups of S. aureus (I-IV).

  14. 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

  15. 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

  16. Screening for autoinducer synthase gene in Sinorhizobium meliloti and analysis of the autoinducer produced by recombinant expression in Escherichia coli%中华根瘤菌自体诱导物合成酶基因的筛选及其在大肠杆菌中的表达

    Institute of Scientific and Technical Information of China (English)

    汪洋; 郑会明; 杨梦华; 钟增涛; 朱军

    2007-01-01

    通过携带有mariner转座子的质粒pJZ290随机插入诱变中华根瘤菌(Sinorhizobium meliloti)建立突变子文库,并从中筛选到自体诱导物(autoinducer,AI)部分缺失突变株YW1.Arbitrary PCR扩增、DNA测序得到YW1基因组DNA中mariner转座子两端侧翼序列,经DNA序列拼接在GenBank上进行同源性分析后获得一个621bp的完整的开放阅读框(ORF),该ORF编码的酶具有206个氨基酸,与草木樨中华根瘤菌(Sinorhizobium medicae)WSM419的LuxI类自体诱导物合成酶(autoinducer synthase)TraI的同源性高达99%.因此,也将该基因命名为traⅠ.将该基因克隆到广宿主范围表达载体pYC12并在大肠杆菌Escherichia coli DH5α中成功表达,C18反相薄层层析(TLC)在阳性重组子培养上清中检测到四种自体诱导物分子,其中的两种正是AI缺失突变株YW1所缺失的AI,这些结果表明该traⅠ基因在苜蓿中华根瘤菌负责合成两种自体诱导物分子,为进一步研究其群体感应系统奠定了理论基础.

  17. [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.

  18. 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.

  19. 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.

  20. 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.

  1. Quantitative Analysis of Autoinducing Peptide I (AIP-I) from Staphylococcus aureus Cultures using Ultrahigh Performance Liquid Chromatography – High Resolving Power Mass Spectrometry

    Science.gov (United States)

    Junio, Hiyas A.; Todd, Daniel A.; Ettefagh, Keivan A.; Ehrmann, Brandie M.; Kavanaugh, Jeffrey S.; Horswill, Alexander R.; Cech, Nadja B.

    2013-01-01

    Staphylococcus aureusinfections acquired in hospitals now cause more deaths per annum in the US than does HIV/AIDS. Perhaps even more alarming is the rise in community associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections, which have spread out of hospital settings and are infecting otherwise healthy individuals. The mechanism of enhanced pathogenesis in CA-MRSA remains unclear, but it has been postulated that high activity in the agr quorum-sensing system could be a contributing factor. The purpose of this study was to develop a quantitative method for analysis of autoinducing peptide I (AIP-I), the activating signal for the agr system in S. aureus. An effective method was developed using ultrahigh performance liquid chromatography (UHPLC) coupled to electrospray ionization mass spectrometry with an LTQ Orbitrap mass spectrometer. Relying on the exceptional resolving power and mass accuracy of this instrument configuration, it was possible to quantify AIP-I directly from the complex growth media of S. aureus cultures with a limit of detection (LOD) of 0.25 μM and a linear dynamic range of 2.3 to 63 μM. The method was then employed to monitor time-dependent production of AIP-I by S. aureus cultures, and it was observed that AIP-I production reached a maximum and leveled off after approximately 16 hrs. Finally, it was determined that virulence of S. aureus was correlated with AIP-I production in some (but not all) strains analyzed. PMID:23703543

  2. Determination of autoinducer-2 in biological samples by high-performance liquid chromatography with fluorescence detection using pre-column derivatization.

    Science.gov (United States)

    Song, Xiang-Ning; Qiu, Hai-Bin; Xiao, Xiang; Cheng, Yuan-Yuan; Li, Wen-Wei; Sheng, Guo-Ping; Li, Xiao-Yan; Yu, Han-Qing

    2014-09-26

    Autoinducer-2 (AI-2), as a small-molecular-weight organic molecule secreted and perceived by various bacteria, enables intra- and inter-species communications. Quantitative determination of AI-2 is essential for exploring the bacterial AI-2-related physiological and biochemical processes. However, current strategies for sensitive detection of AI-2 require sophisticated instruments and complicated procedures. In this work, on the basis of the derivatization of AI-2 with 2,3-diaminonaphthalene, a simple, sensitive and cost-effective high-performance liquid chromatography with fluorescence detector (HPLC-FLD) method is developed for the quantitative detection of AI-2. Under the optimized conditions, this method had a broad linear range of 10-14,000 ng/ml (R(2)=0.9999), and a low detection limit of 1.0 ng/ml. Furthermore, the effectiveness of this approach was further validated through measuring the AI-2 concentrations in the cell-free culture supernatants of both Escherichia coli and Vibrio harveyi.

  3. 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.

  4. 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.

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

    Science.gov (United States)

    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.

  6. 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.

  7. 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.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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...

  16. 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.

  17. 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,...

  18. 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...

  19. 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.

  20. 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).

  1. 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).

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Structural characterization of native autoinducing peptides and abiotic analogues reveals key features essential for activation and inhibition of an AgrC quorum sensing receptor in Staphylococcus aureus.

    Science.gov (United States)

    Tal-Gan, Yftah; Ivancic, Monika; Cornilescu, Gabriel; Cornilescu, Claudia C; Blackwell, Helen E

    2013-12-11

    Staphylococcus aureus is a major human pathogen that uses quorum sensing (QS) to control virulence. Its QS system is regulated by macrocyclic peptide signals (or autoinducing peptides (AIPs)) and their cognate transmembrane receptors (AgrCs). Four different specificity groups of S. aureus have been identified to date (groups I-IV), each of which uses a different AIP:AgrC pair. Non-native ligands capable of intercepting AIP:AgrC binding, and thereby QS, in S. aureus have attracted considerable interest as chemical tools to study QS pathways and as possible antivirulence strategies for the treatment of infection. We recently reported a set of analogues of the group-III AIP that are capable of strongly modulating the activity of all four AgrC receptors. Critical to the further development of such ligands is a detailed understanding of the structural features of both native AIPs and non-native analogues that are essential for activity. Herein, we report the first three-dimensional structural analysis of the known native AIP signals (AIPs-I-IV) and several AIP-III analogues with varied biological activities using NMR spectroscopy. Integration of these NMR studies with the known agonism and antagonism profiles of these peptides in AgrC-III revealed two key structural elements that control AIP-III (and non-native peptide) activity: (1) a tri-residue hydrophobic "knob" essential for both activation and inhibition and (2) a fourth anchor point on the exocyclic tail needed for receptor activation. These results provide strong structural support for a mechanism of AIP-mediated AgrC activation and inhibition in S. aureus , and should facilitate the design of new AgrC ligands with enhanced activities (as agonists or antagonists) and simplified chemical structures.

  8. Production of autoinducer 2 in Salmonella enterica serovar Thompson contributes to its fitness in chickens but not on cilantro leaf surfaces.

    Science.gov (United States)

    Brandl, M T; Miller, W G; Bates, A H; Mandrell, R E

    2005-05-01

    Food-borne illness caused by Salmonella enterica has been linked traditionally to poultry products but is associated increasingly with fresh fruits and vegetables. We have investigated the role of the production of autoinducer 2 (AI-2) in the ability of S. enterica serovar Thompson to colonize the chicken intestine and the cilantro phyllosphere. A mutant of S. enterica serovar Thompson that is defective in AI-2 production was constructed by insertional mutagenesis of luxS. The population size of the S. enterica serovar Thompson parental strain was significantly higher than that of its LuxS(-) mutant in the intestine, spleen, and droppings of chicks 12 days after their oral inoculation with the strains in a ratio of 1:1. In contrast, no significant difference in the population dynamics of the parental and LuxS(-) strain was observed after their inoculation singly or in mixtures onto cilantro plants. Digital image analysis revealed that 54% of S. enterica serovar Thompson cells were present in large aggregates on cilantro leaves but that the frequency distributions of the size of aggregates formed by the parental strain and the LuxS(-) mutant were not significantly different. Carbon utilization profiles indicated that the AI-2-producing strain utilized a variety of amino and organic acids more efficiently than its LuxS(-) mutant but that most sugars were utilized similarly in both strains. Thus, inherent differences in the nutrients available to S. enterica in the phyllosphere and in the chicken intestine may underlie the differential contribution of AI-2 synthesis to the fitness of S. enterica in these environments.

  9. Quorum-sensing systems LuxS/autoinducer 2 and Com regulate Streptococcus pneumoniae biofilms in a bioreactor with living cultures of human respiratory cells.

    Science.gov (United States)

    Vidal, Jorge E; Howery, Kristen E; Ludewick, Herbert P; Nava, Porfirio; Klugman, Keith P

    2013-04-01

    Streptococcus pneumoniae forms organized biofilms in the human upper respiratory tract that may play an essential role in both persistence and acute respiratory infection. However, the production and regulation of biofilms on human cells is not yet fully understood. In this work, we developed a bioreactor with living cultures of human respiratory epithelial cells (HREC) and a continuous flow of nutrients, mimicking the microenvironment of the human respiratory epithelium, to study the production and regulation of S. pneumoniae biofilms (SPB). SPB were also produced under static conditions on immobilized HREC. Our experiments demonstrated that the biomass of SPB increased significantly when grown on HREC compared to the amount on abiotic surfaces. Additionally, pneumococcal strains produced more early biofilms on lung cells than on pharyngeal cells. Utilizing the bioreactor or immobilized human cells, the production of early SPB was found to be regulated by two quorum-sensing systems, Com and LuxS/AI-2, since a mutation in either comC or luxS rendered the pneumococcus unable to produce early biofilms on HREC. Interestingly, while LuxS/autoinducer 2 (AI-2) regulated biofilms on both HREC and abiotic surfaces, Com control was specific for those structures produced on HREC. The biofilm phenotypes of strain D39-derivative ΔcomC and ΔluxS QS mutants were reversed by genetic complementation. Of note, SPB formed on immobilized HREC and incubated under static conditions were completely lysed 24 h postinoculation. Biofilm lysis was also regulated by the Com and LuxS/AI-2 quorum-sensing systems.

  10. 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.

  11. Caracterização morfocultural, biossíntese de autoindutor e formação de biofilme por rizobactérias de hortaliças Morphocultural characterization, autoinducer biosynthesis and biofilm formation in rhizobacteria isolated from vegetable crops

    Directory of Open Access Journals (Sweden)

    Rachel Pinton

    2010-03-01

    Full Text Available O objetivo deste trabalho foi caracterizar e agrupar rizobactérias, isoladas de hortaliças, quanto à morfologia cultural, riqueza e diversidade e avaliar a biossíntese de autoindutores N-acil lactonas homoserinas (ALH e a capacidade de formação de biofilmes. Sete estirpes também foram avaliadas quanto ao potencial de promoção de crescimento de Brassica oleraceae var. acephala em casa de vegetação. Para verificar a produção de ALH, foram realizados ensaios com Agrobacterium tumefaciens estirpe NT1 como sistema repórter. A formação de biofilme foi avaliada pelo cultivo do isolado em meio líquido. A promoção do crescimento foi avaliada após inoculação das estirpes em plantas de couve-de-folha pela determinação da produção de massa de matérias fresca e seca. A maior diversidade morfocultural foi encontrada entre as estirpes isoladas de couve-de-folha. De um total de 112 estirpes testadas, 13% foram positivas quanto à produção de ALH; de 91 estirpes, 96% foram capazes de formar biofilmes; e de 79 estirpes, 11% foram positivas para ambas as características. Foram observadas diferenças significativas na massa de matéria seca das raízes com inoculação de 10(9 UFC mL-1 da estirpe R142, que incrementou em 55% a massa de matéria seca das raízes de couve, em relação ao controle. Não há relação entre a capacidade de formar biofilme e a detecção de ALH produzidos pelas rizobactérias avaliadas.The objective of this work was to characterize and group rhizobacteria isolated from vegetable crops for culture morphology, richness and diversity, and to evaluate the biosynthesis of N-acyl homoserine lactone (AHL autoinducers and the capacity to form biofilms. Seven strains were also assessed for their potential to promote plant growth of Brassica oleraceae var. acephala in greenhouse. To test the production of AHL, the indicator strain Agrobacterium tumefaciens NT1 was used. The formation of biofilms was evaluated by

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

    were used to visualize AHL-mediated communication in mixed biofilms, which were cultivated either in artificial flow chambers or in alginate beads in mouse lung tissue. In both model systems B. cepacia was capable of perceiving the AHL signals produced by P. aeruginosa, while the latter strain did......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...

  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. 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.

  19. (1S-1,2-O-Benzylidene-α-d-glucurono-6,3-lactone

    Directory of Open Access Journals (Sweden)

    David J. Watkin

    2009-02-01

    Full Text Available X-ray crystallographic analysis has established that the major product from the protection of d-glucoronolactone with benzaldehyde is (1S-1,2-O-benzylidene-α-d-glucurono-6,3-lactone, C13H12O6, rather than the R epimer. The crystal structure exists as O—H...O hydrogen-bonded chains of molecules lying parallel to the a axis. The absolute configuration was determined by the use of d-glucuronolactone as the starting material.

  20. A Facile and Efficient Synthesis of (15R)-Latanoprost from Chiral Precursor Corey Lactone Diol

    Indian Academy of Sciences (India)

    K Vijendhar; B Srinivas; Sathyanarayana Boodida

    2015-11-01

    An efficient asymmetric synthetic route for the synthesis of anti-glaucoma agent, (15R)-latanoprost using Corey lactone diol as chiral substrate under Swern oxidation, allylic reduction and Wittig reaction conditions has been developed. In this method, reduction of keto and alkene functional groups has been achieved in a single step using low cost catalyst NiCl2/NaBH4 in methanol. This new synthetic protocol is a good alternative for the synthesis of latanoprost with high stereo selectivity and improved yield.

  1. 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.

  2. Estrogenic potencies of resorcylic acid lactones and 17 beta-estradiol in female rats.

    Science.gov (United States)

    Everett, D J; Perry, C J; Scott, K A; Martin, B W; Terry, M K

    1987-01-01

    Uterotrophic response in sexually immature female rats has been used to rank the relative estrogenic potencies of six resorcylic acid lactones (RALs) and to compare their activities with that of 17 beta-estradiol. On oral administration, the estrogenic potency relative to 17 beta-estradiol is as follows: 7 alpha-zearalenol, 10 times less; zeranol, 150 times less; taleranol, 350 times less; zearalanone, 400 times less; zearalenone, 650 times less; 7 beta-zearalenol, 3500 times less. On subcutaneous administration, zeranol is 500 times less estrogenic than 17 beta-estradiol.

  3. Stereodivergent and Protecting-Group-Free Synthesis of the Helicascolide Family: A Rhodium-Catalyzed Atom-Economical Lactonization Strategy.

    Science.gov (United States)

    Haydl, Alexander M; Berthold, Dino; Spreider, Pierre A; Breit, Bernhard

    2016-05-04

    Natural products of polyketide origin, in particular small-sized lactones often possess a very broad range of impressive biological activities. An efficient way to demonstrate the concise access to six-membered lactones was emphasized as part of a stereodivergent and protecting-group-free synthesis of all three representatives of the helicascolide family. This strategy features an atom-economical and highly diastereoselective rhodium-catalyzed "head-to-tail" lactonization by an intramolecular addition of ω-allenyl-substituted carboxylic acids to terminal allenes, including the selective construction of a new stereocenter in the newly formed core structures. The excellent selectivities with which the helicascolide precursors were obtained are remarkable, thus resulting in an expeditious and highly efficient natural product synthesis.

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

    Science.gov (United States)

    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.

  5. DDQ-promoted dehydrogenation from natural rigid polycyclic acids or flexible alkyl acids to generate lactones by a radical ion mechanism.

    Science.gov (United States)

    Ding, Ye; Huang, Zhangjian; Yin, Jian; Lai, Yisheng; Zhang, Shibo; Zhang, Zhiguo; Fang, Lei; Peng, Sixun; Zhang, Yihua

    2011-09-07

    A novel and facile DDQ-mediated dehydrogenation from natural rigid polycyclic acids or flexible alkyl acids to generate lactones is described. The formation of lactones proceeds by a radical ion mechanism, which has been established by DPPH˙-mediated chemical identification, ESR spectroscopy and an enol intermediate trapping.

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

    Science.gov (United States)

    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.

  7. In vitro antitrypanosomal activity of some phenolic compounds from propolis and lactones from Fijian Kawa (Piper methysticum).

    Science.gov (United States)

    Otoguro, Kazuhiko; Iwatsuki, Masato; Ishiyama, Aki; Namatame, Miyuki; Nishihara-Tsukashima, Aki; Kiyohara, Hiroaki; Hashimoto, Toshihiro; Asakawa, Yoshinori; Omura, Satoshi; Yamada, Haruki

    2012-07-01

    During our search to discover new antitrypanosomal compounds, eight known plant compounds (three phenolic compounds and five kawa lactones) were evaluated for in vitro activity against Trypanosoma brucei brucei. Among them, we found two phenolic compounds and three kawa lactones possessing an α-pyrone influenced antitrypanosomal property. In particular, β-phenethyl caffeate, farnesyl caffeate and dihydrokawain exhibited high or moderate selective and potent antitrypanosomal activity in vitro. We detail here the antitrypanosomal activity and cytotoxicities of the compounds, in comparison with two commonly used antitrypanosomal drugs (eflornithine and suramin). Our findings represent the first report of the promising trypanocidal activity of these compounds.

  8. In Helicobacter pylori auto-inducer-2, but not LuxS/MccAB catalysed reverse transsulphuration, regulates motility through modulation of flagellar gene transcription

    Directory of Open Access Journals (Sweden)

    Doherty Neil

    2010-08-01

    Full Text Available Abstract Background LuxS may function as a metabolic enzyme or as the synthase of a quorum sensing signalling molecule, auto-inducer-2 (AI-2; hence, the mechanism underlying phenotypic changes upon luxS inactivation is not always clear. In Helicobacter pylori, we have recently shown that, rather than functioning in recycling methionine as in most bacteria, LuxS (along with newly-characterised MccA and MccB, synthesises cysteine via reverse transsulphuration. In this study, we investigated whether and how LuxS controls motility of H. pylori, specifically if it has its effects via luxS-required cysteine metabolism or via AI-2 synthesis only. Results We report that disruption of luxS renders H. pylori non-motile in soft agar and by microscopy, whereas disruption of mccAHp or mccBHp (other genes in the cysteine provision pathway does not, implying that the lost phenotype is not due to disrupted cysteine provision. The motility defect of the ΔluxSHp mutant was complemented genetically by luxSHp and also by addition of in vitro synthesised AI-2 or 4, 5-dihydroxy-2, 3-pentanedione (DPD, the precursor of AI-2. In contrast, exogenously added cysteine could not restore motility to the ΔluxSHp mutant, confirming that AI-2 synthesis, but not the metabolic effect of LuxS was important. Microscopy showed reduced number and length of flagella in the ΔluxSHp mutant. Immunoblotting identified decreased levels of FlaA and FlgE but not FlaB in the ΔluxSHp mutant, and RT-PCR showed that the expression of flaA, flgE, motA, motB, flhA and fliI but not flaB was reduced. Addition of DPD but not cysteine to the ΔluxSHp mutant restored flagellar gene transcription, and the number and length of flagella. Conclusions Our data show that as well as being a metabolic enzyme, H. pylori LuxS has an alternative role in regulation of motility by modulating flagellar transcripts and flagellar biosynthesis through production of the signalling molecule AI-2.

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

    Science.gov (United States)

    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.

  10. Effects of lactone, ketone, and phenolic compounds on methane production and metabolic intermediates during anaerobic digestion.

    Science.gov (United States)

    Wikandari, Rachma; Sari, Noor Kartika; A'yun, Qurrotul; Millati, Ria; Cahyanto, Muhammad Nur; Niklasson, Claes; Taherzadeh, Mohammad J

    2015-02-01

    Fruit waste is a potential feedstock for biogas production. However, the presence of fruit flavors that have antimicrobial activity is a challenge for biogas production. Lactones, ketones, and phenolic compounds are among the several groups of fruit flavors that are present in many fruits. This work aimed to investigate the effects of two lactones, i.e., γ-hexalactone and γ-decalactone; two ketones, i.e., furaneol and mesifurane; and two phenolic compounds, i.e., quercetin and epicatechin on anaerobic digestion with a focus on methane production, biogas composition, and metabolic intermediates. Anaerobic digestion was performed in a batch glass digester incubated at 55 °C for 30 days. The flavor compounds were added at concentrations of 0.05, 0.5, and 5 g/L. The results show that the addition of γ-decalactone, quercetin, and epicathechin in the range of 0.5-5 g/L reduced the methane production by 50 % (MIC50). Methane content was reduced by 90 % with the addition of 5 g/L of γ-decalactone, quercetin, and epicathechin. Accumulation of acetic acid, together with an increase in carbon dioxide production, was observed. On the contrary, γ-hexalactone, furaneol, and mesifurane increased the methane production by 83-132 % at a concentration of 5 g/L.

  11. Synthesis and characterization of novel quick-release propofol prodrug via lactonization.

    Science.gov (United States)

    Yang, Jun; Yin, Wang; Liu, Jin; Wang, Yu; Zhou, Cheng; Kang, Yi; Zhang, Wen-Sheng

    2013-03-15

    The water-soluble derivatives of propofol have gained attention as a method to increase solubility of propofol. According to the principle of lactonization, the lead compound HX0969 was synthesized first and then the pharmacological features of HX0969 were evaluated in a comparison with those of propofol in the SD rats. Then, HX0969 disodium phosphate monoester (HX0969W) and glycine ester trifluoroacetic acid salt (HX101230) were synthesized, and their pharmacological features were compared with those of Lusedra®, which has been recognized and marketed as a water-soluble prodrug of propofol since 2008. The results showed that HX0969 could produce an anesthetic effect within a few seconds (3.6±3.0s) and its therapeutic index was 4.66 in the SD rat. The pharmacodynamic characteristics of HX0969W were similar to those of the Lusedra®. HX101230 could still produce an anesthetic effect within 60s in the rats though its therapeutic index was not so high (TI=2.96). Therefore, our study has indicated that HX0969 is a potentially useful lead compound of propofol derivative. Its rapid anesthetic effect is probably associated with lactonization.

  12. Antiviral and antimicrobial activities of three sesquiterpene lactones from Centaurea solstitialis L. ssp. solstitialis.

    Science.gov (United States)

    Ozçelik, Berrin; Gürbüz, Ilhan; Karaoglu, Taner; Yeşilada, Erdem

    2009-01-01

    Three sesquiterpene lactones (centaurepensin = chlorohyssopifolin A, chlorojanerin and 13-acetyl solstitialin A) isolated from the aerial parts of Centaurea solstitialis L. ssp. solstitialis (Asteraceae) were investigated for antimicrobial and antiviral activities. For the antimicrobial activity assessment, both standard and isolated strains of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida albicans and C. parapsilosis were employed by the microdilution method. Herpes simplex type-1, a DNA virus, and Parainfluenza, an RNA virus, were employed for the determination of the antiviral activity of these three sesquiterpene lactones using Vero cell lines. Ampicilline, ofloxocine, ketoconazole, fluconazole, acyclovir and oseltamivir were used as the reference drugs. 13-Acetyl solstitialin A displayed remarkable antibacterial activity against isolated strains of E. faecalis at 1 microg/ml concentration, which was close to the effective concentrations of ampicillin. The same compound also showed significant activity against the DNA virus, being as potent as the reference compound acyclovir at maximum and minimum concentrations of 16-<0.00006 microg/ml. This is the first report showing that 13-acetyl solstitialin A possesses significant antiviral activity.

  13. 银杏萜内酯的分布与矮壮素对其生物合成的调节%Distribution of terpene lactones in Ginkgo biloba and the regulation effect of chlorocholine chloride on their biosynthesis

    Institute of Scientific and Technical Information of China (English)

    冷平生; 苏淑钗; 蒋湘宁; 王天华; 王沙生

    2004-01-01

    Terpene lactone contents in different organs of Ginkgo biloba L.and leaf,stem and root of G.biloba seedlings treated with chlorocholine chloride were determined by GC.The results showed that total terpene lactone contents in the order from high to low were bud(1.973mg·g-1),leaf(1.753mg·g-1),root,stem,and the terpene lactone in phloem was higher than that in xylem,leaf contained more bilobalide than root and stem.Chlorocholine chloride treatment significantly increased terpene lactone content of G.biloba seedlings.The possible way of terpene lactone biosynthesis was discussed.

  14. 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.

  15. Penicillin V acylases from gram-negative bacteria degrade N-acylhomoserine lactones and attenuate virulence in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Sunder, Avinash Vellore; Utari, Putri Dwi; Ramasamy, Sureshkumar; van Merkerk, Ronald; Quax, Wim J.; Pundle, Archana

    2016-01-01

    Virulence pathways in gram-negative pathogenic bacteria are regulated by quorum sensing mechanisms, through the production and sensing of N-acylhomoserine lactone (AHL) signal molecules. Enzymatic degradation of AHLs leading to attenuation of virulence (quorum quenching) could pave the way for the d

  16. Anodic coupling of carboxylic acids to electron-rich double bonds: A surprising non-Kolbe pathway to lactones

    Directory of Open Access Journals (Sweden)

    Robert J. Perkins

    2013-08-01

    Full Text Available Carboxylic acids have been electro-oxidatively coupled to electron-rich olefins to form lactones. Kolbe decarboxylation does not appear to be a significant competing pathway. Experimental results indicate that oxidation occurs at the olefin and that the reaction proceeds through a radical cation intermediate.

  17. Stereoselective synthesis of highly substituted bicyclic γ-lactones using homoaldol addition of 1-(1-cycloalkenyl)methyl carbamates

    DEFF Research Database (Denmark)

    Özlügedik, M.; Kristensen, Jesper Langgaard; Reuber, J.;

    2004-01-01

    Stereoselective addition of aldehydes 4 to metallated 1-(1-cycloalkenyl) methyl N,N-diisopropylcarbamates 1 gave cyclic homoaldol adducts 6. By applying the (-)-sparteine method, enantiomerically enriched products were obtained. These were oxidatively cyclized to diastereomerically pure ¿-lactone...

  18. 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...

  19. Artemisinin-derived sesquiterpene lactones as potential antitumour compounds : Cytotoxic action against bone marrow and tumour cells

    NARCIS (Netherlands)

    Beekman, AC; Wierenga, PK; Woerdenbag, HJ; Van Uden, W; Pras, N; Konings, AWT; El-Feraly, FS; Galal, AM; Wikstrom, HV

    1998-01-01

    We determined the in vitro cytotoxic activity of the sesquiterpene lactone endoperoxide artemisinin (1) and some chemically prepared derivatives, which have been found to display cytotoxicity to cloned murine Ehrlich ascites tumour (EAT) cells and human HeLa cells and against murine bone marrow usin

  20. CYTOTOXICITY OF FLAVONOIDS AND SESQUITERPENE LACTONES FROM ARNICA SPECIES AGAINST THE GLC(4) AND THE COLO-320 CELL-LINES

    NARCIS (Netherlands)

    WOERDENBAG, HJ; MERFORT, [No Value; PASSREITER, CM; SCHMIDT, TJ; WILLUHN, G; VANUDEN, W; PRAS, N; KAMPINGA, HH; KONINGS, AWT

    1994-01-01

    The cytotoxicity of 21 flavonoids and 5 sesquiterpene lactones, as present in Arnica species, was studied in GLC(4), a human small cell lung carcinoma cell line, and in COLO 320, a human colorectal cancer cell line, using the microculture tetrazolium (MTT) assay. Following continuous incubation, mos

  1. EFSA ; Scientific Opinion on Flavouring Group Evaluation 98 (FGE.98): Consideration of three ring-unsaturated delta-lactones)

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of three unsaturated delta-lactones [FL-no: 10.031, 10.037 and 10.044] previously evaluated by the JECFA at their 49th meeting in 1997. The JECFA considered that further information...

  2. 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.

  3. Azalomycin F4a 2-ethylpentyl ester, a new macrocyclic lactone, from mangrove actinomycete Streptomyces sp.211726

    Institute of Scientific and Technical Information of China (English)

    Gan Jun Yuan; Kui Hong; Hai Peng Lin; Jia Li

    2010-01-01

    Azalomycin F4a 2-ethylpentyl ester,a new 36-membered macrocyclic lactone antibiotic,was isolated from mangrove actinomycete Streptomyces sp.211726.Its structure was elucidated on the basis of spectroscopic data.The compound showed broad-spectrum antifungal activity and moderate cytotoxicity against human colon tumor cell HCT-116.

  4. INVESTIGATION OF HYPOLIPIDEMIC EFFECT OF SESQUITERPENE Γ-LACTONE AHILLIN IN HEPATOMA TISSUE CULTURE (HTC CELLS

    Directory of Open Access Journals (Sweden)

    V. V. Ivanov

    2014-01-01

    Full Text Available Objective. Investigation of hypolipidemic effect of sesquiterpene γ-lactone ahillin in hepatoma tissue culture (HTC cells.Material and methods. In this study we’ve evaluated the effect of γ-lactone sesquiterpene aсhillin and gemfibrozil (comparator drug on the lipid content in the hepatoma tissue culture (HTC cell which were incubated with a fat emulsion lipofundin by fluorescent method with vital dye Nile Redand staining the cells with the dye Oil Red O. The cell viability was investigated using the MTT-test and staining with Trypan blue.Results. Cultivation cells HTC with aсhillin and gemfibrozilat concentrations ranging from 0.5 to1.5 mM and from0.25 mM to0.5 mM, respectively, resulted in dose-dependent decrease of the fluorescence’s intensity Nile Red. It reflects a decrease in lipid content in the cells. At these concentrations the drugs didn’t have cytotoxic effect and the cell viability didn’t change compared to the control culture.An experimental hyperlipidemia in the hepatoma culture cells was induced by adding to the incubation medium a fat emulsion lipofundin at a final concentration 0.05%. The intensity of fluorescence Nile Red in the cells was increased 4 fold (p < 0.05. This result suggests the significant accumulation of lipids in the cell’s cytosol and confirmed by microscopy after staining neutral lipids with the dye Oil Red O. Under these conditions aсhillin and gemfibrozil reduced lipid content in cells and hadthe effect at concentrations of0.5 mM and0.25 mM respectively.Conclusion. In the lipofundin-mediated model of hyperlipidemia the sesquiterpene lactone aсhillin prevents the lipid accumulation in cells. It confirms by decrease of fluorescence Nile Red and reduction lipid drops which were stained with Oil Red O in cytosol. To establish the molecular targets of aсhillin’saction on lipid metabolism in cell culture HTC we need to investigate a gene expression of key enzymes of lipid metabolism.

  5. Validation of a screening method for rapid control of macrocyclic lactone mycotoxins in maize flour samples.

    Science.gov (United States)

    Zougagh, Mohammed; Téllez, Helena; Sánchez, Alberto; Chicharro, Manuel; Ríos, Angel

    2008-05-01

    A procedure for the analytical validation of a rapid supercritical fluid extraction amperometric screening method for controlling macrocyclic lactone mycotoxins in maize flour samples has been developed. The limit established by European legislation (0.2 mg kg(-1)), in reference to zearalenone (ZON) mycotoxin, was taken as the reference threshold to validate the proposed method. Natural ZON metabolites were also included in this study to characterize the final screening method. The objective was the reliable classification of samples as positive or negative samples. The cut-off level was fixed at a global concentration of mycotoxins of 0.17 mg kg(-1). An expanded unreliability zone between 0.16 and 0.23 mg kg(-1) characterized the screening method for classifying the samples. A set of 30 samples was used for the final demonstration of the reliability and usefulness of the method.

  6. Three New .β-Resorcylic Acid Lactones from Paecflomyces sp. SC0924

    Institute of Scientific and Technical Information of China (English)

    徐良雄; 薛琮花; 邹永; 何树杰; 魏孝义

    2012-01-01

    Three new β-resorcylic acid lactones (RALs), paecilomycins G-I (1--3), and eight known compounds, aigia- lomycins B--D (4--6), 1',2'-epoxy aigialomycin D (7), zearalenone (8), 7'-dehydrozearalenone (9), and trans-7',8'-dehydrozearalenol (10), antibiotic LL-Z1640-1 (11), were isolated from the mycelial solid culture of Paecilomyces sp. SC0924. Their structures were established by spectroscopic methods and chemical means. In an assessment of antifungal activity by the well plate diffusion method, five known RALs, 4-7 and 11 showed weak activities against Peronophythora litchii.

  7. Sesquiterpene lactone content in leaves of in vitro and field cultivated Arnica montana.

    Science.gov (United States)

    Schmidt, T J; Bomme, U; Alfermann, A W

    1998-04-01

    On the basis of GC and GC/MS analyses we report on the full qualitative and quantitative sesquiterpene lactone (STL) content of in vitro cultivated A. montana plantlets consisting of helenalin and 11alpha,13-dihydrohelenalin esters in approximately equal amounts. The accumulation of STL was shown to be correlated with tissue differentiation in the above-ground parts. The seasonal variation of STL content in leaves of A. montana cultivated in the proving field was investigated. Changes in the composition of the STL fraction were detected. While young plants accumulate mainly helenalin derivatives, the content of such compounds decreases to almost zero within about 6 weeks from the beginning of leaf formation while that of dihydrohelenalin type compounds increases at the same rate and remains constant for a longer period.

  8. New γ -Lactone Carboxylic Acids from the Lichen Parmotrema praesorediosum (Nyl. Hale, Parmeliaceae

    Directory of Open Access Journals (Sweden)

    Bui Linh Chi Huynh

    2016-05-01

    Full Text Available From the lichen Parmotrema praesorediosum (Nyl. Hale, Parmeliaceae, collected in Vietnam, five new (1, 2, 3, 5, 6 and one known (4 g -lactonic acids were isolated. The structures of the new compounds were established by 1D and 2D NMR spectroscopy, as well as high resolution-electrospray ionization (HR-ESI-MS analysis. The absolute configuration of new compounds was determined by ultraviolet circular dichroism spectroscopy. Compounds were evaluated for their cytotoxic activity against HeLa (human epithelial carcinoma, NCI-H460 (human lung cancer and MCF-7 (human breast cancer cell lines at the concentration of 100 µg/mL. Among six compounds, 1 possessed medium activity against MCF-7 cell line with the inhibition of 52.5%. Meanwhile, the rest showed no cytotoxic activity against three surveyed cancer cell lines.

  9. 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.

  10. Simultaneous determination of three sesquiterpene lactones in Aucklandia lappa Decne by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Chang-Seob Seo

    2015-01-01

    Full Text Available Background: Aucklandia lappa Decne, a well known traditional herbal medicine, is used for the treatment of asthma, rheumatism, coughs, tuberculosis, and many other diseases. Objective: We performed simultaneous analysis of three sesquiterpene lactones, costunolide (1, dehydrocostus lactone (2, and alantolactone (3, obtained from a 70% methanol extract of A. lappa using high performance liquid chromatography–photodiode array (HPLC–PDA techniques. Materials and Methods: The compounds 1–3 were separated using a reversed phase SunFire™ C18 analytical column kept at 35°C by the isocratic elution with distilled water and acetonitrile as mobile phase. The flow rate was 1.0 mL/min, and the injection volume was 10 μL. Results: The established analytical method showed high linearity, with a correlation coefficient ≥0.9999. The limit of detection and the limit of quantification of compounds 1–3 were 0.06–0.13 μg/mL and 0.21–0.42 μg/mL, respectively. The recovery of the compounds 1–3 was 97.27–103.00%. The intra and inter day relative standard deviations were 0.09–0.97% and 0.09–1.06%, respectively. The amounts of the compounds 1–3 were 17.32, 28.26, and 0.01 mg/g, respectively. Conclusion: The established and validated HPLC–PDA method may be help for the quality control of herbal medicine, A. lappa.

  11. Anti-inflammatory sesquiterpene lactones from Lychnophora trichocarpha Spreng. (Brazilian Arnica).

    Science.gov (United States)

    Ferrari, Fernanda C; Ferreira, Leidiane C; Souza, Maíra R; Grabe-Guimarães, Andrea; Paula, Carmen A; Rezende, Simone A; Saúde-Guimarães, Dênia A

    2013-03-01

    The aerial parts of Lychnophora trichocarpha Spreng. (Asteraceae) are used macerated in water or ethanol to treat inflammation, pain, rheumatism, contusions, bruises and insect bites in Brazilian traditional medicine. In this study, anti-inflammatory activity of ethanol extract from aerial parts of L. trichocarpha and its ethyl acetate fraction was investigated. Sesquiterpene lactones, lychnopholide (Lyc) and eremantholide C (EreC), isolated of ethyl acetate fraction, were also assayed for in vitro and in vivo anti-inflammatory activity. Topical treatment with ointments containing ethanol extract, its ethyl acetate fraction and sesquiterpene lactones significantly reduced carrageenan-induced mice paw oedema. In vitro assays demonstrated that Lyc inhibited interferon -γ/lipopolysaccharide -stimulated nitric oxide (NO) production in J774A.1 macrophages and increased production of IL-10 anti-inflammatory cytokine. The reduction of tumor necrosis factor-α (TNF-α) production by EreC was accompanied by an increased production of IL-10 in a concentration-dependent manner in J774A.1 macrophages. The anti-inflammatory effect of Lyc seems to involve the inhibition of production of NO and increased production of IL-10. The mechanism of the effect of EreC on the reduction of carrageenan-induced paw oedema may be attributed to inhibition of production of TNF-α and stimulation of IL-10 production. The results corroborate the use of ethanol extract from Lychnophora trichocarpha in folk medicine for anti-inflammatory action and indicate that the topical route is suitable for use.

  12. Approach toward the total synthesis of griseoviridin: formation of thioethynyl and thiovinyl ether-containing nine-membered lactones through a thioalkynylation-macrolactonization-hydrostannylation sequence.

    Science.gov (United States)

    Kuligowski, Carine; Bezzenine-Lafollée, Sophie; Chaume, Grégory; Mahuteau, Jacqueline; Barrière, Jean-Claude; Bacqué, Eric; Pancrazi, Ange; Ardisson, Janick

    2002-06-28

    Synthesis of the lactone core 17 of 8-epi-griseoviridin is reported. Thioethynyl derivative 11 was easily prepared via an anionic coupling reaction between acetylenic compound 9 and sulfone 10. After desilylation of 11, saponification of the resulting hydroxy ester 12 followed by a Mitsunobu macrolactonization furnished the unusual triple-bond-containing nine-membered lactone 13 in 50% yield for the last two steps (39% after recrystallization). Stannylation under Magriotis conditions led to the pure regio- and stereocontrolled vinyltin 14 (80% yield). After a Sn/I exchange, palladium-catalyzed carbonylation delivered either the ester lactone 16 in 67% yield or the propargyl amide 17 in 65% yield. Synthesis of propargyl amide 17 of the lactone core of 8-epi-griseoviridin was achieved in 11.9% overall yield from commercial L-cystin dimethyl ester (nine steps).

  13. Broad tuning of the human bitter taste receptor hTAS2R46 to various sesquiterpene lactones, clerodane and labdane diterpenoids, strychnine, and denatonium.

    Science.gov (United States)

    Brockhoff, Anne; Behrens, Maik; Massarotti, Alberto; Appendino, Giovanni; Meyerhof, Wolfgang

    2007-07-25

    Sesquiterpene lactones are a major class of natural bitter compounds occurring in vegetables and culinary herbs as well as in aromatic and medicinal plants, where they often represent the main gustatory and pharmacologically active component. Investigations on sesquiterpene lactones have mainly focused on their bioactive potential rather than on their sensory properties. In the present study, we report about the stimulation of heterologously expressed human bitter taste receptors, hTAS2Rs, by the bitter sesquiterpene lactone herbolide D. A specific response to herbolide D was observed i.a. for hTAS2R46, a so far orphan bitter taste receptor without any known ligand. By further investigation of its agonist pattern, we characterized hTAS2R46 as a bitter receptor broadly tuned to sesquiterpene lactones and to clerodane and labdane diterpenoids as well as to the unrelated bitter substances strychnine and denatonium.

  14. A concise route to branched erythrono-gamma-lactones. Synthesis of the leaf-closing substance potassium (+/-)-(2R,3R)-2,3,4-trihydroxy-2-methylbutanoate

    DEFF Research Database (Denmark)

    Pedersen, Daniel Sejer; Robinson, Tony V; Taylor, Dennis K;

    2009-01-01

    A series of 1,2-dioxanes 3 were ring-opened with Co(SALEN)(2) to furnish lactol regioisomers 4 and 5 (86-99% yield). The lactols were oxidized to gamma-lactones 8 and 9 (72-96% yield) and deprotected to afford the 2-C- and 3-C-alkyl and aryl branched erythrono-gamma-lactones 1, 6, and 7 (65-94% y...

  15. 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.

  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

    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...

  17. 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

    Vibrio anguillarum produces several interlinked acylated homoserine lactone (AHL) signal molecules which may Vibrio anguillarum produces several interlinked acylated homoserine lactone (AHL) signal molecules which may influence expression of its virulence factors such as exoprotease production...... 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...

  18. Binding modes of phosphotriesterase-like lactonase complexed with δ-nonanoic lactone and paraoxon using molecular dynamics simulations.

    Science.gov (United States)

    Guan, Shanshan; Zhao, Li; Jin, Hanyong; Shan, Ning; Han, Weiwei; Wang, Song; Shan, Yaming

    2017-02-01

    Phosphotriesterase-like lactonases (PLLs) have received much attention because of their physical and chemical properties. They may have widespread applications in various fields. For example, they show potential for quorum-sensing signaling pathways and organophosphorus (OP) detoxification in agricultural science. However, the mechanism by which PLLs hydrolyze, which involves OP compounds and lactones and a variety of distinct catalytic efficiencies, has only rarely been explored. In the present study, molecular dynamics (MD) simulations were performed to characterize and contrast the structural dynamics of DrPLL, a member of the PLL superfamily in Deinococcus radiodurans, bound to two substrates, δ-nonanoic lactone and paraoxon. It has been observed that there is a 16-fold increase in the catalytic efficiency of the two mutant strains of DrPLL (F26G/C72I) vs. the wild-type enzyme toward the hydrolysis of paraoxon, but an explanation for this behavior is currently lacking. The analysis of the molecular trajectories of DrPLL bound to δ-nonanoic lactone indicated that lactone-induced conformational changes take place in loop 8, which is near the active site. Binding to paraoxon may lead to conformational displacement of loop 1 residues, which could lead to the deformation of the active site and so trigger the entry of the paraoxon into the active site. The efficiency of the F26G/C72I mutant was increased by decreasing the displacement of loop 1 residues and increasing the flexibility of loop 8 residues. These results provide a molecular-level explanation for the experimental behavior.

  19. 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...... for the secretion of extracellular lipase, metalloprotease, and S-layer protein...

  20. 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

  1. Accelerations in the Lactonization of Trimethyl Lock Systems Are due to Proximity Orientation and not to Strain Effects

    Directory of Open Access Journals (Sweden)

    Rafik Karaman

    2009-01-01

    Full Text Available DFT at B3LYP/6-31G(d,p and HF at 6-31G and AM1 semiempirical calculations of thermodynamc and kinetic parameters for the trimethyl lock system (an important enzyme model indicate that the remarkable enhancement in the lactonizations is largely the result of a proximity orientation as opposed to the currently advanced strain effect.

  2. Asymmetric synthesis of highly substituted β-lactones through oxidative carbene catalysis with LiCl as cooperative Lewis acid.

    Science.gov (United States)

    Bera, Srikrishna; Samanta, Ramesh C; Daniliuc, Constantin G; Studer, Armido

    2014-09-01

    The reaction of enals with β-diketones, β-ketoesters, and malonates bearing a β-oxyalkyl substituent at the α-position by oxidative NHC catalysis to provide highly substituted β-lactones is described. Reactions occur with excellent diastereo- and enantioselectivity. The organo cascade comprises two CC bond formations and one CO bond formation. Up to four contiguous stereogenic centers including two fully substituted stereocenters are formed in the cascade.

  3. Ficusmicrochlorin A-C, two new methoxy lactone chlorins and an anhydride chlorin from the leaves of Ficus microcarpa.

    Science.gov (United States)

    Lin, Huan-You; Chiu, Hsi-Lin; Lu, Te-Ling; Tzeng, Chih-Ying; Lee, Tzong-Huei; Lee, Ching-Kuo; Shao, Yi-Yuan; Chen, Chiy-Rong; Chang, Chi-I; Kuo, Yueh-Hsiung

    2011-01-01

    Two new methoxy lactone chlorins ficusmicrochlorin A (1) and ficusmicrochlorin B (2), and one new anhydride chlorin ficusmicrochlorin C (3), along with eight known pheophytins were isolated from the leaves of Ficus microcarpa. Their structures were determined by the extensive 1D- and 2D-NMR techniques. New pheophytin compound was rarely obtained from natural sources. In the past ten years, only three new natural pheophytins were characterized.

  4. Processing of Lacton Bean Curd with Soybean and Fruit%水果内酯豆腐的研制

    Institute of Scientific and Technical Information of China (English)

    冯文红; 周生民; 李翠; 张玲; 方建; 高钊; 赵伟

    2015-01-01

    以苹果汁与大豆为原料制作具有水果清香的内酯豆腐。对影响内酯豆腐的各个因素进行试验并优化,以内酯豆腐的外观和口感等因素为评判指标,最终确定最优搭配为豆浆与苹果汁比例为8.5∶1.5、内酯添加量为2g/L和凝固温度为85℃。%Special lacton bean curd was made of apple juice and soybean. Factors of lacton bean curd processing had been experiment and optimization. With appearance and texture as selection standard, optimum conditions were as followed:soybean milk∶apple juice is 8.5∶1.5, 0.2%lacton and 85℃solidification temperature.

  5. 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.

  6. A novel kindling model of temporal lobe epilepsy in rhesus monkeys induced by Coriaria lactone.

    Science.gov (United States)

    Hong, Zhen; Yang, Tian-Hua; Tang, Ming-Hai; Zhang, Heng; Li, Hong-Xia; Chen, Lei; Chen, Qin; Zhou, Dong

    2013-12-01

    One of the major challenges in developing novel therapeutics for human epileptic disorders derives from the limitation of knowledge of the processes by which epilepsy is generated (epileptogenesis). Furthermore, the inability to obtain human samples at the early stage of epilepsy hinders studies designed to further understand epileptogenesis. Thus, an effective animal model is critical for studies investigating this process. The purpose of this study was to establish a new primate kindling model of temporal lobe epilepsy (TLE) as an animal model of epileptogenesis. Here, repeated injections of Coriaria lactone (CL) at a subthreshold dose elicited partial seizures that culminated in secondarily generalized tonic-clonic seizures. The sequence of events and features of the behaviors observed in this model simulated those observed in human TLE. Electroencephalogram monitoring revealed the temporal lobe origins of the epileptiform potentials, which were consistent with the behavioral changes observed. A total of 7 rhesus monkeys (78%) were kindled with a median of 48 (41 to 60) CL injections. Both the seizure-induction and mortality rates were dose-dependent. A CL injection at 1.50mg/kg showed the lowest animal mortality rate (0%) and the highest seizure-induction rate (100%). Extensive kindling by CL injections with a median of 97 injections (overkindling) subsequently resulted in the recurrence of spontaneous seizures in rhesus monkeys with frequency patterns that were similar to those observed in human TLE. In addition, rhesus monkeys subjected to large numbers of kindling stimuli displayed mitochondrial damage and astrocyte activation in a pattern that was similar to the neuropathological changes characteristic of human TLE. Thus, a kindling TLE model in rhesus monkeys representing a primate animal model of epileptogenesis was established for the first time using repeated intramuscular injections of Coriaria lactone. This model was easily and efficiently performed

  7. 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.

  8. Antiplasmodial Activity of Aporphine Alkaloids and Sesquiterpene Lactones from Liriodendron tulipifera L

    Science.gov (United States)

    Graziose, Rocky; Rathinasabapathy, Thirumurugan; Lategan, Carmen; Poulev, Alexander; Smith, Peter J; Grace, Mary; Lila, Mary Ann; Raskin, Ilya

    2010-01-01

    Aim of the study The objective of this study was to isolate and characterize the active constituents of the traditionally used antimalarial plant Liriodendron tulipifera by antiplasmodial-assay guided fractionation. Materials and methods Bark and leaves were extracted with solvents of increasing polarity. Fractions were generated using flash chromatography, counter current chromatography and preparative HPLC and subjected to in vitro antiplasmodial and cytotoxicity assays. Active fractions were subjected to further fractionation until pure compounds were isolated, for which the IC50 values were calculated. Results and discussion Six known aporphine alkaloids, asimilobine (1), norushinsunine (2), norglaucine (3), liriodenine (4), anonaine (5) and oxoglaucine (6) were found to be responsible for the antiplasmodial activity of the bark. Leaves yielded two known sesquiterpene lactones, peroxyferolide (7) and lipiferolide (8) with antiplasmodial activity. The antiplasmodial activity of (2) (IC50 = 29.6 μg/ml), (3) (IC50 = 22.0 μg/ml), (6) (IC50= 9.1 μg/mL), (7) (IC50 = 6.2 μg/ml) and (8) (IC50 = 1.8 μg/ml) are reported for the first time. Conclusion This work supports the historical use of Liriodendron tulipifera as an antimalarial remedy of the United States and characterizes its antiplasmodial constituents. PMID:20826204

  9. D-glucaro 1,4-lactone and resveratrol as antioxidants in blood platelets.

    Science.gov (United States)

    Olas, Beata; Saluk-Juszczak, Joanna; Wachowicz, Barbara

    2008-04-01

    The aim of our work was to study the anti-aggregatory and antioxidative effects of natural dietary products, D-glucaro 1,4-lactone (1,4-GL) in combination with phenolic compound resveratrol (trans-3,4',5-trihydroxystilbene). Our results in vitro showed that 1,4-GL alone slightly inhibits platelet aggregation induced by thrombin. The combination of resveratrol (0.1 microM) with 0.5 mM of 1,4-GL caused a significant decrease of thrombin-induced platelet aggregation; however separately, neither of studied compound at used concentrations was not effective. When platelets were treated with 1,4-GL (at the concentration of 0.1 mM and higher) and resveratrol (0.1 microM), similar synergistic action of both tested compound on markers of oxidative stress formation was observed. We measured the levels of different specific markers of oxidative stress, e.g., superoxide anion radicals O(2)(-)*, thiobarbituric acid-reactive substances and carbonyl group formation. Both tested compounds inhibited also the generation of O(2)(-)* and malondialdehyde that represents enzymatical peroxidation of arachidonic acid leading to thromboxane A(2) (TXA(2)) formation in platelets after thrombin stimulation. The obtained in vitro results demonstrate that anti-platelet and antioxidative properties of resveratrol may be significantly augmented by another dietary agent such as 1,4-GL, but mechanism synergistic action of these compounds is not yet known.

  10. 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.

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

    Science.gov (United States)

    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.

  12. [Gamma-hydroxybutyrate (GHB) and its lactone (GBL) as psychoactive substances].

    Science.gov (United States)

    Krajewska, Anna; Kwiecień-Obara, Ewelina; Szponar, Jarosław; Majewska, Magdalena; Kołodziej, Małgorzata

    2012-01-01

    Gammabutyrolactone is included in the solvent such as wheel cleaners, pesticides, cosmetics, drugs. After ingestion GBL is converted to gamma-hydroxybutyrate. Both substances are classified as so called "club drugs" and their action is characterized by euphoria, sedation, and induction of retrograde amnesia of events. These activities were basis for the use of GHB and its lactone as rape pill. Acute poisoning with these compounds causes confusion, agitation, ataxia, nausea, vomiting, nystagmus, dyskinesia, hallucinations, coma, irregular breathing, hypothermia, bradycardia, hypotension, convulsions, respiratory paralysis and thus respiratory arrest. These substances carry a risk of development of physical addiction of the hard proceeding of abstinence syndrome. In the USA there is a ban on the sale and promotion of these compounds. In Poland despite the fact that GHB is a controlled substance, there is no regulation of GBL trading. The aim of this paper is to summarize current knowledge regarding the pharmacology, impact on the human body, toxicity, and the effects of chronic abuse of these substances.

  13. Involvement of N-acylhomoserine lactones throughout plant infection by Erwinia carotovora subsp. atroseptica (Pectobacterium atrosepticum).

    Science.gov (United States)

    Smadja, Bruno; Latour, Xavier; Faure, Denis; Chevalier, Sylvie; Dessaux, Yves; Orange, Nicole

    2004-11-01

    Erwinia carotovora subsp. atroseptica is responsible for potato blackleg disease in the field and tuber soft rot during crop storage. The process leading to the disease occurs in two phases: a primary invasion step followed by a maceration step. Bacteria-to-bacteria communication is associated with a quorum-sensing (QS) process based on the production of N-acylhomoserine lactones (HSL). The role of HSL throughout plant infection was analyzed. To this purpose, HSL produced by a specific E. carotovora subsp. atroseptica wild-type strain, which was particularly virulent on potato, were identified. A derivative of this strain that expressed an HSL lactonase gene and produced low amounts of HSL was generated. The comparison of these strains allowed the evaluation of the role of HSL and QS in disease establishment and development. Bacterial growth and motility; activity of proteins secreted by type I, II, and III systems; and hypersensitive and maceration reactions were evaluated. Results indicated that HSL production and QS regulate only those traits involved in the second stage of the host plant infection (i.e., tissue maceration) and hypersensitive response in nonhost tobacco plants. Therefore, the use of QS quenching strategies for biological control in E. carotovora subsp. atroseptica cannot prevent initial infection and multiplication of this pathogen.

  14. Inactivation of the cytotoxic activity of repin, a sesquiterpene lactone from Centaurea repens.

    Science.gov (United States)

    Tukov, Francis F; Anand, S; Gadepalli, Rama Sarma V S; Gunatilaka, A A Leslie; Matthews, John C; Rimoldi, John M

    2004-09-01

    Prolonged ingestion of Yellow Starthistle (Centaurea solstitialis) and Russian Knapweed (Centaurea repens) by horses has been shown to result in a fatal neurodegenerative disorder called equine nigropallidal encephalomalacia (ENE). Bioassay-guided fractionation of extracts from Centaurea species using the PC12 cell line have led to the identification of one of several putative agents, which may contribute to ENE, namely, the sesquiterpene lactone (SQL) repin (1), previously linked to ENE due to its abundance in C. repens. To characterize the molecular basis of repin-induced neurotoxicity, the present study was designed to identify reactive functional groups that may contribute overall to its toxicity. The reaction of repin (1) with glutathione (GSH) led to the exclusive addition of GSH to the alpha-methylenebutyrolactone affording a GSH conjugate (3b) that lacked toxicity in the PC12 cell assay, while selective reduction of the alpha-methylenebutyrolactone double bond of 1 also resulted in an analogue (2) that was devoid of toxicity relative to the parent compound. Unlike repin, analogue 2 failed to decrease cellular dopamine levels in PC12 cells, further substantiating the requirement of the alpha-methylenebutyrolactone group. Results from this study are suggestive that GSH depletion by the SQL repin may be a primary event in the etiology of ENE, increasing the susceptibility to oxidative damage.

  15. Effect of the sesquiterpene lactone incomptine A in the energy metabolism of Entamoeba histolytica.

    Science.gov (United States)

    Velázquez-Domínguez, José; Marchat, Laurence A; López-Camarillo, Cesar; Mendoza-Hernández, Guillermo; Sánchez-Espíndola, Esther; Calzada, Fernando; Ortega-Hernández, Alfredo; Sánchez-Monroy, Virginia; Ramírez-Moreno, Esther

    2013-11-01

    Entamoeba histolytica is the causative agent of human amoebiasis, which mainly affects developing countries. Although several drugs are effective against E. histolytica trophozoites, the control of amoebiasis requires the development of new and better alternative therapies. Medicinal plants have been the source of new molecules with remarkable antiprotozoal activity. Incomptine A isolated from Decachaeta incompta leaves, is a sesquiterpene lactone of the heliangolide type which has the major in vitro activity against E. histolytica trophozoites. However the molecular mechanisms involved in its antiprotozoal activity are still unknown. Using a proteomic approach based on two-dimensional gel electrophoresis and mass spectrometry (ESI-MS/MS) analysis, we evidenced that 21 E. histolytica proteins were differentially expressed in response to incomptine A treatment. Notably, three glycolytic enzymes, namely enolase, pyruvate:ferredoxin oxidoreductase and fructose-1,6-biphosphate aldolase, were down-regulated. Moreover, ultrastructural analysis of trophozoites through electronic microscopy showed an increased number of glycogen granules. Taken together, our data suggested that incomptine A could affect E. histolytica growth through alteration of its energy metabolism.

  16. 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.

  17. Identification of New Lactone Derivatives Isolated from Trichoderma sp., An Endophytic Fungus of Brotowali (Tinaspora crispa

    Directory of Open Access Journals (Sweden)

    Elfita

    2014-03-01

    Full Text Available Endophytic fungi is a rich source of novel organic compounds with interesting biological activities and a high level of structural diversity. As a part of our systematic search for new bioactive lead structures and specific profiles from endophytic fungi, an endophytic fungus was isolated from roots of brotowali (Tinaspora crispa, an important medicinal plant. Colonial morphological trait and microscopic observation revealed that the endophytic fungus was Trichoderma sp. The pure fungal strain was cultivated on 7 L Potatos Dextose Broth (PDB medium under room temperature (no shaking for 8 weeks. The ethyl acetate were added to cultur medium and left overnight to stop cell growth. The culture filtrates were collected and extracted with EtOAc and then taken to evaporation. Two new lactone derivatives, 5-hydroxy-4-hydroxymethyl-2H-pyran-2-one (1 and (5-hydroxy-2-oxo-2H pyran-4-yl methyl acetate (2 were obtained from the EtOAc extracts of Trichoderma sp. Their structures were determined on the basic of spectroscopic methods including UV, IR, 1H-NMR, 13C-NMR, HMQC, and HMBC.

  18. New sesquiterpene lactones from Arnica tincture prepared from fresh flowerheads of Arnica montana.

    Science.gov (United States)

    Kos, Olha; Lindenmeyer, Maja T; Tubaro, Aurelia; Sosa, Silvio; Merfort, Irmgard

    2005-11-01

    Investigation of an ethanolic extract prepared from fresh Arnica montana flowers afforded three new 1,5- trans-guaianolides, of which 11alpha,13-dihydro-2-O-tigloylflorilenalin and the respective 2-O-isovaleryl derivative are reported for the first time. Additionally, three new and one known 2beta-ethoxy-2,3-dihydrohelenalin esters were isolated. GC/MS studies of the extract after a two year storage at 4 degrees C demonstrated that the latter were artefacts that had been formed by addition of ethanol to the cyclopentenone structure of helenalin. Formation of these adducts gave compounds possessing an inhibitory activity comparable to that of 11alpha,13-dihydrohelenalin derivatives in the NF-kappaB EMSA and the IL-8 ELISA in vitro assays as well as in the in vivo croton oil-induced mouse ear edema test for one adduct, namely 2beta-ethoxy-6-O-acetyl-2,3-dihydrohelenalin. As expected, 6-O-(2-methylbutyryl)- and 6-O-methacryloyl-helenalin exhibited a stronger activity in the NF-kappaB EMSA and IL-8 ELISA. Sesquiterpene lactones seem to be the most important NF-kappaB inhibiting compounds in the Arnica extract. Bioguided fractionation using the luciferase reporter gene assay resulted in the isolation of only moderately active compounds, such as 6-acetoxy-2,2-dimethylchroman-4-one and 10-acetoxy-8,9-epoxythymol isobutyrate.

  19. Variation of sesquiterpene lactone contents in different Arnica montana populations: influence of ecological parameters.

    Science.gov (United States)

    Seemann, Andreas; Wallner, Teresa; Poschlod, Peter; Heilmann, Jörg

    2010-05-01

    In ten grassland or heathland sites along a geographic (north to south) and climatic gradient in Germany, flowerheads of Arnica montana were collected, and the total content of sesquiterpene lactones (SLs) as well as the content of the detected single compounds were determined. The ratios of helenalin (H)- and corresponding 11 alpha,13-dihydrohelenalin(DH)-type compounds were calculated. All habitats were characterised concerning the climatic and soil conditions, and the values obtained were correlated with SL contents according to univariate statistical analyses. All populations showed very similar and constant ratios of helenalin ( 1)/11 alpha,13-dihydrohelenalin ( 2) at around 1.5-2/1 irrespective of different ecological parameters. The ratio of helenalin/11 alpha,13-dihydrohelenalin esters was several fold higher in all samples, but it was nearly identical in every habitat among each other, except for the helenalin/11 alpha,13-dihydrohelenalin 2-methylbutyrate pair ( 5/ 11), which showed a constantly twofold higher H/DH ratio. However, the 6- O-isovalerylhelenalin content ( 6) showed highly significant correlations to climatic factors.

  20. Sesquiterpene lactones in Arnica montana: helenalin and dihydrohelenalin chemotypes in Spain.

    Science.gov (United States)

    Perry, Nigel B; Burgess, Elaine J; Rodríguez Guitián, Manuel A; Romero Franco, Rosa; López Mosquera, Elvira; Smallfield, Bruce M; Joyce, Nigel I; Littlejohn, Roger P

    2009-05-01

    An analytical RPLC method for sesquiterpene lactones in Arnica montana has been extended to include quantitative analyses of dihydrohelenalin esters. LC-ESI-MS-MS distinguished the isomeric helenalin and dihydrohelenalin esters. The dihydrohelenalin esters have lower response factors for UV detection than do helenalin esters, which must be taken into account for quantitative analyses. Analyses of flowers from 16 different wild populations of A. montana in Spain showed differing proportions of helenalin and dihydrohelenalin esters. For the first time a chemotype with high levels of helenalin esters (total helenalins 5.2-10.3 mg/g dry weight) is reported in Spanish A. montana. These samples were from heath lands at high altitude (1330-1460 m), whereas samples from meadows and peat bogs at lower altitudes were the expected chemotype with high levels of dihydrohelenalin esters (total dihydrohelenalins 10.9-18.2 mg/g). The phenolic compounds, both flavonoid glycosides and caffeoylquinic acids, in Spanish A. montana are reported for the first time. The levels of several of these compounds differed significantly between samples from heath lands and samples from peat bogs or meadows, with the heath land samples being most similar to central European A. montana in their phenolic composition.

  1. Styryl-lactone goniothalamin inhibits TNF-α-induced NF-κB activation.

    Science.gov (United States)

    Orlikova, Barbora; Schumacher, Marc; Juncker, Tom; Yan, Choo Chee; Inayat-Hussain, Salmaan H; Hajjouli, Shéhérazade; Cerella, Claudia; Dicato, Mario; Diederich, Marc

    2013-09-01

    (R)-(+)-Goniothalamin (GTN), a styryl-lactone isolated from the medicinal plant Goniothalamus macrophyllus, exhibits pharmacological activities including cytotoxic and anti-inflammatory effects. In this study, GTN modulated TNF-α induced NF-κB activation. GTN concentrations up to 20 μM showed low cytotoxic effects in K562 chronic myelogenous leukemia and in Jurkat T cells. Importantly, at these concentrations, no cytotoxicity was observed in healthy peripheral blood mononuclear cells. Our results confirmed that GTN inhibited tumor necrosis factor-α (TNF-α)-induced NF-κB activation in Jurkat and K562 leukemia cells at concentrations as low as 5 μM as shown by reporter gene assays and western blots. Moreover, GTN down-regulated translocation of the p50/p65 heterodimer to the nucleus, prevented binding of NF-κB to its DNA response element and reduced TNF-α-activated interleukin-8 (IL-8) expression. In conclusion, GTN inhibits TNF-α-induced NF-κB activation at non-apoptogenic concentrations in different leukemia cell models without presenting toxicity towards healthy blood cells underlining the anti-leukemic potential of this natural compound.

  2. Fluensulfone is a nematicide with a mode of action distinct from anticholinesterases and macrocyclic lactones.

    Science.gov (United States)

    Kearn, James; Ludlow, Elizabeth; Dillon, James; O'Connor, Vincent; Holden-Dye, Lindy

    2014-02-01

    Plant parasitic nematodes infest crops and present a threat to food security worldwide. Currently available chemical controls e.g. methyl bromide, organophosphates and carbamates have an unacceptable level of toxicity to non-target organisms and are being withdrawn from use. Fluensulfone is a new nematicide of the fluoroalkenyl thioether group that has significantly reduced environmental impact with low toxicity to non-target insects and mammals. Here, we show that the model genetic organism Caenorhabditis elegans is susceptible to the irreversible nematicidal effects of fluensulfone. Whilst the dose required is higher than that which has nematicidal activity against Meloidogyne spp. the profile of effects on motility, egg-hatching and survival is similar to that reported for plant parasitic nematodes. C. elegans thus provides a tractable experimental paradigm to analyse the effects of fluensulfone on nematode behaviour. We find that fluensulfone has pleiotropic actions and inhibits development, egg-laying, egg-hatching, feeding and locomotion. In the case of feeding and locomotion, an early excitation precedes the gross inhibition. The profile of these effects is notably distinct from other classes of anthelmintic and nematicide: the inhibition of motility caused by fluensulfone is not accompanied by the hypercontraction which is characteristic of organophosphates and carbamates and C. elegans mutants that are resistant to the carbamate aldicarb and the macrocyclic lactone ivermectin retain susceptibility to fluensulfone. These data indicate fluensulfone's mode of action is distinct from currently available nematicides and it therefore presents a promising new chemical entity for crop protection.

  3. Quantification of Sesquiterpene Lactones in Asteraceae Plant Extracts: Evaluation of their Allergenic Potential.

    Science.gov (United States)

    Salapovic, Helena; Geier, Johannes; Reznicek, Gottfried

    2013-01-01

    Sesquiterpene lactones (SLs), mainly those with an activated exocyclic methylene group, are important allergens in Asteraceae (Compositae) plants. As a screening tool, the Compositae mix, consisting of five Asteraceae plant extracts with allergenic potential (feverfew, tansy, arnica, yarrow, and German chamomile) is part of several national patch test baseline series. However, the SL content of the Compositae mix may vary due to the source material. Therefore, a simple spectrophotometric method for the quantitative measurement of SLs with the α-methylene-γ-butyrolactone moiety was developed, giving the percentage of allergenic compounds in plant extracts. The method has been validated and five Asteraceae extracts, namely feverfew (Tanacetum parthenium L.), tansy (Tanacetum vulgare L.), arnica (Arnica montana L.), yarrow (Achillea millefolium L.), and German chamomile (Chamomilla recutita L. Rauschert) that have been used in routine patch test screening were evaluated. A good correlation could be found between the results obtained using the proposed spectrophotometric method and the corresponding clinical results. Thus, the introduced method is a valuable tool for evaluating the allergenic potential and for the simple and efficient quality control of plant extracts with allergenic potential.

  4. Sensitive quantification of six steroidal lactones in Withania coagulans extract by UHPLC electrospray tandem mass spectrometry.

    Science.gov (United States)

    Ali, Arslan; Maher, Saima; Khan, Shahid Ali; Chaudhary, M Iqbal; Musharraf, Syed Ghulam

    2015-12-01

    A method for the concurrent determination of six known steroidal lactones (syn. withanolides or withasteroids), namely withaferin A, withanolide H, withanolide K, withanolide A, withacoagulin H, and withanolide J in Withania coagulans extracts was developed. Extracts of Withania species and purified withanolides are considered among the most important natural products used for medicinal purposes. Methanolic extract of plant material was subjected to reverse phase ultra-high performance liquid chromatography (UHPLC) coupled with electrospray (JetStream ESI) triple quadrupole mass spectrometer operated in the Multiple Reaction Monitoring (MRM) mode. Satisfactory separation of withanolide component was achieved within 9 min on UHPLC runtime. The limits of detection (LOD) and the limits of quantitation (LOQs) for the six withanolides ranged between 0.040-4.80 ng/mL, and 0.13-16 ng/mL, respectively. Linear responses were attained for all six withanolides in two orders of magnitude with the linear regression coefficient values ⩾0.998. At the five QC levels inspected, the relative standard deviations (RSD) were found below 5% in most cases. The newly developed method is fast, precise, and sensitive, therefore, the method can be used for high-throughput quantification of various withanolides in W. coagulans extract, and other herbal formulations, derived from W. coagulans.

  5. Bacillus marcorestinctum sp. nov., a Novel Soil Acylhomoserine Lactone Quorum-Sensing Signal Quenching Bacterium

    Directory of Open Access Journals (Sweden)

    Xianzhen Li

    2010-02-01

    Full Text Available 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 relatives based on the 16S rRNA gene sequence are Bacillus anthracis, Bacillus thuringiensis, and Brevibacillus brevis (syn. Bacillus brevis with the similarity of 96.5%. The DNA–DNA hybridization data indicates a low level of genomic relatedness with the relative type strains of Bacillus thuringiensis (6.1%, Bacillus anthracis (10.5% and Brevibacillus brevis (8.7%. On the basis of the phenotypic and phylogenetic data together with the genomic distinctiveness, the LQQ strain represents a novel species of the genus Bacillus, for which the name Bacillus marcorestinctum sp. nov. is proposed. The type strain is LQQT.

  6. 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.

  7. 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.

  8. Antiplasmodial activity of sesquiterpene lactones and a sucrose ester from Vernonia guineensis Benth. (Asteraceae)

    Science.gov (United States)

    Toyang, Ngeh J.; Krause, Michael A.; Fairhurst, Rick M.; Tane, Pierre; Bryant, Joseph; Verpoorte, Rob

    2013-01-01

    Ethnopharmacological relevance Aqueous preparations of Vernonia guineensis Benth. (Asteraceae) are used in Cameroonian folk medicine as a general stimulant and to treat various illnesses and conditions including malaria, bacterial infections and helminthic infestations. Materials and methods 10-g samples of the leaf and tuber powders of V. guineensis were extracted separately using dichloromethane, methanol and distilled water. The extracts were dried in vacuo and used in bioassays. These extracts and three compounds previously isolated from V. guineensis [vernopicrin (1), vernomelitensin (2) and pentaisovalerylsucrose (3)] were screened for antiplasmodial activity against chloroquine (CQ)-sensitive (Hb3) and CQ-resistant (Dd2) Plasmodium falciparum lines. Results Crude extracts and pure compounds from V. guineensis showed antiplasmodial activity against both Hb3 and Dd2. The IC50 values of extracts ranged from 1.64 – 27.2 μg/ml for Hb3 and 1.82 – 30.0 μg/ml for Dd2; those for compounds 1, 2 and 3 ranged from 0.47 – 1.62 μg/ml (1364 – 1774 nM) for Hb3 and 0.57 – 1.50 μg/ml (1644 – 2332 nM) for Dd2. None of the crude extracts or pure compounds was observed to exert toxic effects on the erythrocytes used to cultivate the P. falciparum lines. Conclusion In Cameroonian folk medicine, V. guineensis may be used to treat malaria in part due to the antiplasmodial activity of sesquiterpene lactones (1, 2), a sucrose ester (3) and perhaps other compounds present in crude plant extracts. Exploring the safety and antiplasmodial efficacy of these compounds in vivo requires further study. PMID:23542146

  9. 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.

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

    Science.gov (United States)

    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.

  11. 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.

  12. Characterization of Haemonchus contortus P-glycoprotein-16 and its interaction with the macrocyclic lactone anthelmintics.

    Science.gov (United States)

    Godoy, P; Che, H; Beech, R N; Prichard, R K

    2015-11-01

    Anthelmintic resistance in veterinary nematodes, including Haemonchus contortus, has become a limitation to maintaining high standards of animal health. Resistance in this parasite, to all drug families including the macrocyclic lactones (MLs) is a serious issue worldwide. Mechanisms of resistance to the MLs appear to be complex and to include the elimination of these compounds by ABC transporter-like proteins present in nematodes. In order to investigate the potential involvement of ABC transporters in ML resistance in H. contortus, we have characterized the functionality of the ABC transporter H. contortus P-glycoprotein-16 (Hco-PGP-16) expressed in mammalian cells. This has included a study of its interaction with different MLs, including the avermectins, abamectin (ABA) and ivermectin (IVM), and the milbemycin, moxidectin (MOX). Hco-PGP-16 transport activity was studied using the fluorophore Rhodamine 123 (Rho 123). Transfected cells expressing Hco-PGP-16 accumulated less than 50% of Rho 123 than control cells, suggesting an active transport of this tracer dye by Hco-PGP-16. The influence of the MLs on the Rho123 transport by Hco-PGP-16 was then investigated. A marked inhibition of Rho123 transport by ABA and IVM was observed. In contrast, MOX showed less effect on inhibition of Rho123 transport by Hco-PGP-16, and the inhibition was not saturable. The difference in the interaction of the avermectins and MOX with Hco-PGP-16 may help explain the slower rate of development of resistance to MOX compared with the avermectins in H. contortus.

  13. 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

  14. Trypanocidal Activity of Smallanthus sonchifolius: Identification of Active Sesquiterpene Lactones by Bioassay-Guided Fractionation

    Directory of Open Access Journals (Sweden)

    F. M. Frank

    2013-01-01

    Full Text Available In order to find novel plant-derived biologically active compounds against Trypanosoma cruzi, we isolated, from the organic extract of Smallanthus sonchifolius, the sesquiterpene lactones enhydrin (1, uvedalin (2, and polymatin B (3 by bioassay-guided fractionation technique. These compounds showed a significant trypanocidal activity against the epimastigote forms of the parasite with IC50 values of 0.84 μM (1, 1.09 μM (2, and 4.90 μM (3. After a 24 h treatment with 10 μg/mL of enhydrin or uvedalin, parasites were not able to recover their replication rate. Compounds 1 and 2 showed IC50 values of 33.4 μM and 25.0 μM against T. cruzi trypomastigotes, while polymatin B was not active. When the three compounds were tested against the intracellular forms of T. cruzi, they were able to inhibit the amastigote replication with IC50 of 5.17 μM, 3.34 μM, and 9.02 μM for 1, 2, and 3, respectively. The cytotoxicity of the compounds was evaluated in Vero cells obtaining CC50 values of 46.5 μM (1, 46.8 μM (2, and 147.3 μM (3 and the selectivity index calculated. According to these results, enhydrin and uvedalin might have potentials as agents against Chagas disease and could serve as lead molecules to develop new drugs.

  15. 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.

  16. Induction of G2/M arrest and apoptosis by sesquiterpene lactones in human melanoma cell lines.

    Science.gov (United States)

    Rozenblat, Sharon; Grossman, Shlomo; Bergman, Margalit; Gottlieb, Hugo; Cohen, Yigal; Dovrat, Sara

    2008-01-15

    Malignant melanoma is a highly aggressive tumor which frequently resists chemotherapy, therefore, the search for new agents for its treatment is of great importance. In this study, we purified the sesquiterpene lactones (SLs), Tomentosin and Inuviscolide from Inula viscosa (Compositae) leaves and studied their anti-cancer potency against human melanoma cell lines in order to develop new agents for melanoma treatment. SLs inhibited the proliferation of three human melanoma cell lines: SK-28, 624 mel and 1363 mel in a dose-dependent manner. We further investigated SLs mechanism of action using SK-28 as a representative cell line model. SLs caused cell-cycle arrest at G(2)/M, accompanied by the appearance of a sub-G0 fraction, indicative of apoptotic cell death. Induction of apoptosis was further confirmed by changes in membrane phospholipids, changes in mitochondrial membrane potential (DeltaPsi) and by detection of Caspase-3 activity. Rapid inhibitory phosphorylation of Cdc2 (Thr14 and Tyr15) was seen early after treatment, followed by a later decrease in the expression level of both Cyclin b1 and Cdc2. Induction of p53 and p21(waf1) proteins and phosphorylation of p53 at Ser15 were also detected early after treatment. The anti-apoptotic proteins, p65 subunit of nuclear factor kappaB (NF-kappaB), and Survivin were reduced in a dose-dependent manner. Taken together, these changes partially explain the ability of the SLs to induce G(2)/M arrest and apoptosis. Induction of apoptosis by Tomentosin and Inuviscolide in human aggressive melanoma cell lines has high pharmacological value and implies that SLs might be developed as new agents for melanoma treatment.

  17. Concurrent supercritical fluid chromatographic analysis of terpene lactones and ginkgolic acids in Ginkgo biloba extracts and dietary supplements.

    Science.gov (United States)

    Wang, Mei; Carrell, Emily J; Chittiboyina, Amar G; Avula, Bharathi; Wang, Yan-Hong; Zhao, Jianping; Parcher, Jon F; Khan, Ikhlas A

    2016-07-01

    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 GAs simply displayed only the [M-H](-) pseudo-molecular ions, and selected ion monitoring (SIM) for those ions was used for the quantification. Analysis of terpene lactones (ginkgolides A, B, C, J and bilobalide) was complicated by in-source collision-induced dissociation (IS-CID) in the ESI source. Thus, MS analysis could be influenced by the fragmentation pattern produced by the IS-CID. However, it was established that the fragmentation pattern, measured by ion survival yield (ISY), was independent of analyte concentration or matrix at a fixed cone voltage in the ESI source. Therefore, MS with SIM mode was applicable for the analysis of these analytes. The reported method provided consistent and sensitive analysis for the analytes of interest. The LOQs and LODs were determined to be below 100 and 40 ng/mL for GAs and 1 μg/mL and 400 ng/mL for terpene lactones, respectively. Intra- and inter-day precisions were found to be satisfactory with RSDs being below 5.2 %. Analyte recoveries ranged from 87 to 109 %. The developed method was successfully applied to the analysis of 11 ginkgo plant samples and 8 dietary supplements with an analysis time of less than 12 min.

  18. Rubrolides as model for the development of new lactones and their aza analogs as potential photosynthesis inhibitors.

    Science.gov (United States)

    Pereira, Ulisses A; Barbosa, Luiz C A; Demuner, Antônio J; Silva, Antônio A; Bertazzini, Michele; Forlani, Giuseppe

    2015-07-01

    Natural phytotoxins and their synthetic analogs are a potential source of new bioactive compounds for agriculture. Analogs of rubrolides, a class of γ-alkylidene-γ-lactones isolated from different ascidians, have been shown to interfere with the photosynthetic electron-transport chain, yet their activity needs to be improved. With this aim, ten 5-aryl-6-benzyl-4-bromopyridazin-3(2H)-ones were prepared in yields ranging from 44 to 88% by reaction of their correspondent γ-alkylidene-γ-lactones with NH2 NH2 . The structures of these rubrolide analogs were determined by (1) H- and (13) C-NMR, 2D-NMR (COSY and HETCOR), NOE difference, and MS techniques. These compounds were evaluated for their abilities of interfering with the light-driven reduction of ferricyanide by isolated spinach chloroplasts. Lactones with electron-withdrawing substituents in the para-position of the benzylidene ring were the most effective inhibitors. Characterization of the activity of 11b/11b' suggested a mechanism based on the interaction with the plastoquinone binding site of photosystem II. Addition of several compounds to the culture medium of a cyanobacterial model strain was found to inhibit algal growth. However, the relative effectiveness was not consistent with their activity in vitro, suggesting the occurrence of multiple targets and/or detoxyfication mechanisms. Indeed, the compounds showed differential effects on the heterotrophic growth of some crop species, Cucumis sativus and Sorghum bicolor. Pyridazin-3(2H)-ones 12e, 12i, and 12j, which have been found poorly active against the photosynthetic electron transport, were the most effective in inhibiting the growth of some weeds, Ipomoea grandifolia and Brachiaria decumbens, under greenhouse conditions.

  19. Weak and Saturable Protein–Surfactant Interactions in the Denaturation of Apo-α-Lactalbumin by Acidic and Lactonic Sophorolipid

    Science.gov (United States)

    Andersen, Kell K.; Vad, Brian S.; Roelants, Sophie; van Bogaert, Inge N. A.; Otzen, Daniel E.

    2016-01-01

    Biosurfactants are of growing interest as sustainable alternatives to fossil-fuel-derived chemical surfactants, particularly for the detergent industry. To realize this potential, it is necessary to understand how they affect proteins which they may encounter in their applications. However, knowledge of such interactions is limited. Here, we present a study of the interactions between the model protein apo-α-lactalbumin (apo-aLA) and the biosurfactant sophorolipid (SL) produced by the yeast Starmerella bombicola. SL occurs both as an acidic and a lactonic form; the lactonic form (lactSL) is sparingly soluble and has a lower critical micelle concentration (cmc) than the acidic form [non-acetylated acidic sophorolipid (acidSL)]. We show that acidSL affects apo-aLA in a similar way to the related glycolipid biosurfactant rhamnolipid (RL), with the important difference that RL is also active below the cmc in contrast to acidSL. Using isothermal titration calorimetry data, we show that acidSL has weak and saturable interactions with apo-aLA at low concentrations; due to the relatively low cmc of acidSL (which means that the monomer concentration is limited to ca. 0–1 mM SL), it is only possible to observe interactions with monomeric acidSL at high apo-aLA concentrations. However, the denaturation kinetics of apo-aLA in the presence of acidSL are consistent with a collaboration between monomeric and micellar surfactant species, similar to RL and non-ionic or zwitterionic surfactants. Inclusion of diacetylated lactonic sophorolipid (lactSL) as mixed micelles with acidSL lowers the cmc and this effectively reduces the rate of unfolding, emphasizing that SL like other biosurfactants is a gentle anionic surfactant. Our data highlight the potential of these biosurfactants for future use in the detergent and pharmaceutical industry. PMID:27877155

  20. Development of an additive-controlled, SmI2-mediated stereoselective sequence: Telescoped spirocyclisation, lactone reduction and Peterson elimination

    Directory of Open Access Journals (Sweden)

    Brice Sautier

    2013-07-01

    Full Text Available Studies on SmI2-mediated spirocyclisation and lactone reduction culminate in a telescoped sequence in which additives are used to “switch on” individual steps mediated by the electron transfer reagent. The sequence involves the use of two activated SmI2 reagent systems and a silicon stereocontrol element that exerts complete diastereocontrol over the cyclisation and is removed during the final stage of the sequence by Peterson elimination. The approach allows functionalised cyclopentanols containing two vicinal quaternary stereocentres to be conveniently prepared from simple starting materials.

  1. 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...

  2. Further evidence on the intramolecular lactonization in rat liver microsomal metabolism of 12-O-acetylated retronecine-type pyrrolizidine alkaloids.

    Science.gov (United States)

    Tang, Jun; Wang, Zhengtao; Akao, Teruaki; Hattori, Masao

    2013-11-01

    We have previously found evidence of intramolecular lactonization in rat liver microsomal metabolism of isoline, a 12-O-acetylated pyrrolizidine alkaloid. In this study, the metabolism of another 12-O-acetylated pyrrolizidine alkaloid, acetylduciformine, by the proposed transformation pathway was investigated under the same incubation conditions. Two deacetylated metabolites from acetylduciformine were isolated and purified by chromatographic methods, and further characterized based on their physical properties and spectral data. One metabolite (lankongensisine A) was the lactone of another one (duciformine). Both compounds were first obtained as hydrolyzed metabolites from acetylduciformine by rat liver microsomes. More importantly, the present study provided further evidence for the intramolecular lactonization in the microsomal metabolism of 12-O-acetylated retronecine-type PAs.

  3. Carboxymethyl glycoside lactone(CMGL) synthons:Scope of the method and preliminary results on step growth polymerization of α-azide-ω-alkyne glycomonomers

    Institute of Scientific and Technical Information of China (English)

    CHAMBERT; Stéphane; BERNARD; Julien; FLEURY; Etienne; QUENEAU; Yves

    2010-01-01

    Carboxymethyl glycoside lactones(CMGLs) are bicyclic synthons which open readily for accessing new types of pseudo-glycoconjugates,such as sugar-amino acid hybrids,neoglycolipids,pseudodisaccharides,and membrane imaging systems.After lactone opening,free OH-2 is available for further functionalization,leading to 1,2-bisfunctionalized derivatives.This strategy is illustrated herein with new polymerizable systems of the AB type bearing both azide and alkyne functions prepared from α or β gluco-CMGL synthons.After the reaction of lactones with propargylamine,an azido group was introduced by two different sequences leading to either the 2-manno-azido or the 6-gluco-azido products.The capability of these AB monomers to undergo step growth polymerization through copper(I) catalyzed alkyne-azide cycloaddition(CuAAC) and generate glycopolytriazoles was evidenced.

  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. Effects of coriaria lactone-activated, astrocyte-conditioned medium on estrogen receptor and progesterone receptor expression in rat cortical and hippocampal neurons

    Institute of Scientific and Technical Information of China (English)

    Jie Rong; Shuhua Zhang

    2009-01-01

    BACKGROUND: Coriaria lactone-activated astrocytes released bioactive substances that eventually caused epilepsy.OBJECTIVE: It has been suggested that activated astrocytes alter the expression of the estrogen receptor and progesterone receptor by releasing bioactive substances during epilepsy, thereby affecting neuronal activity in the brain. This study was designed to observe the expression of the estrogen receptor and the progesterone receptor in rat brain following lateral ventricle injection of coriaria lactone-activated, astrocyte-conditioned medium.DESIGN AND SETTING: This immunohistochemical, randomized, controlled, animal study was conducted at the Department of Pathology, Hospital Affiliated to Binzhou Medical College, China.MATERIAL: Coriaria lactone was provided by Huaxi Pharmaceutical Factory, China.METHODS: Forty adult, healthy, male, Sprague Dawley rats were randomly assigned into two groups. Astrocyte-conditioned medium (10 μL) was injected into rat lateral ventricle in the control group (n = 8). Coriaria lactone-activated, astrocyte-conditioned medium (10 μL) was infused into the rat lateral ventricle in the coriaria lactone group (n = 32). At 2, 4, 8 and 12 hours following injection, rats were sacrificed and subjected to immunohistochemistry. Eight rats were studied at each time point.MAIN OUTCOME MEASURES: Behavioral changes were observed in rats of both groups. Expression of the estrogen receptor and the progesterone receptor in rat cortical and hippocampal neurons was measured using immunohistochemistry.RESULTS: Four hours after injection, estrogen receptor levels in rat cortical and hippocampal neurons were significantly higher in the coriaria lactone group than in the control group (P < 0.05). Progesterone receptor levels were significantly lower in the coriaria lactone group than in the control group (P < 0.05). Seizures were not observed in the control group. In the coriaria lactone group, convulsions appeared 30 minutes after injection

  6. Synthesis and antiproliferative activity of some A- and B modified D-homo lactone androstane derivatives

    Directory of Open Access Journals (Sweden)

    Savić Marina P.

    2013-01-01

    Full Text Available An efficient synthesis of several A- and B-modified D-homo lactone androstane derivatives from 3β-hydroxy-17-oxa-D-homoandrost-5-en-16-one (1 is reported. 17-Oxa-Dhomoandrost- 4-ene-3,16-dione (2, obtained by the Oppenauer oxidation of compound 1, was converted via the unstable intermediate 3,16-dioxo-4,17-dioxa-D-homoandrostane- 5α-carboxaldehyde (3 to 17-oxa-D-homo-3,5-seco-4-norandrostan-5-one-3-carboxylic acid (4, which was also obtained directly from compound 2. Compound 1 was acetylated to give 17-oxa-D-homoandrost-5-en-16-on-3β-yl acetate (5 which was then oxidized with chromium(VI-oxide in 50% acetic acid or with meta-chlorperbenzoic acid and chromium(VI-oxide to yield compounds 6-8 and 5α-hydroxy-17-oxa-D-homoandrostane- 6,16-dion-3β-yl acetate (9, respectively. The oximination of compound 9 gave a mixture of 6(E-hydroximino-5α-hydroxy-17-oxa-D-homoandrostan-16-on-3β-yl acetate (10 and 6(Z-hydroximino-5α-hydroxy-17-oxa-D-homoandrostan-16-on-3β-yl acetate (11, the hydrolysis of which gave 6(E-hydroximino-3β,5α-dihydroxy-17-oxa-D-homoandrostan- 16-one (12 and 6(Z-hydroximino-3β,5α-dihydroxy-17-oxa-D-homoandrostan-16-one (13. 6-Nitrile-17-oxa-5,6-seco-D-homoandrostane-5,16-dion-3β-yl acetate (14 was obtained under the Beckmann fragmentation of compounds 10 and 11. Only pure and stable compounds (1, 2, 4, 5, 9 and 14 were tested in vitro on six malignant cell lines (MCF-7, MDA-MB-231, PC-3, HeLa, HT-29, K562 and one non-tumor MRC-5 cell line. Significant antiproliferative activity against MDA-MB-231 cells showed compounds 1, 5 and 9, while compound 2 exhibited a strong antiproliferative activity. Only compound 14 showed weak antiproliferative activity against MCF-7 cells. All tested compounds were not toxic on MRC-5 cells, whereas Doxorubicin was highly toxic on these cells. [Projekat Ministarstva nauke Republike Srbije, br. 172021

  7. Lipase-catalyzed synthesis of aliphatic polyesters via copolymerization of lactone, dialkyl diester, and diol.

    Science.gov (United States)

    Jiang, Zhaozhong

    2008-11-01

    Candida antarctica lipase (CALB) has been successfully used as catalyst for copolymerization of dialkyl diester with diol and lactone to form aliphatic polyesters. The polymerization reactions were performed using a two stage process: first stage oligomerization under low vacuum followed by second stage polymerization under high vacuum. Use of the two-stage process is required to obtain products with high molecular weights at high yields for the following reasons: (i) the first stage reaction ensures that the monomer loss via evaporation is minimized to maintain 1:1 diester to diol stoichiometric ratio, and the monomers are converted to nonvolatile oligomers; (ii) use of high vacuum during the second stage accelerates equilibrium transesterification reactions to transform the oligomers to high molecular weight polymers. Thus, terpolymers of omega-pentadecalactone (PDL), diethyl succinate (DES), and 1,4-butanediol (BD) with a M w of whole product (nonfractionated) up to 77000 and M w/ M n between 1.7 and 4.0 were synthesized in high yields (e.g., 95% isolated yield). A desirable reaction temperature for the copolymerizations was found to be around 95 degrees C. At 1:1:1 PDL/DES/BD monomer molar ratio, the resultant terpolymers contained equal moles of PDL, succinate, and butylene repeat units in the polymer chains. (1)H and (13)C NMR analyses were used to determine the polyester microstructures. The synthesized PDL-DES-BD terpolymers possessed near random structures with all possible combinations of PDL, succinate, and butylene units via ester linkages in the polymer backbone. Furthermore, thermal stability and crystallinity of a pure PDL-DES-BD terpolymer with 1:1:1 PDL to succinate to butylene unit ratio and M w of 85400 were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The copolyester was found to be a semicrystalline material with a T g of -34 degrees C and a T m of 64 degrees C, which degrades in a single weight loss

  8. 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.

  9. 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

  10. Molecular characterization and expression studies during melon fruit development and ripening of L-galactono-1,4-lactone dehydrogenase

    DEFF Research Database (Denmark)

    Pateraki, Irene; Sanmartin, Maite; Kalamaki, Mary S.

    2004-01-01

    The last step of ascorbic acid (AA) biosynthesis is catalysed by the enzyme L-galactono-1,4-lactone dehydrogenase (GalLDH, EC 1.3.2.3), located on the inner mitochondrial membrane. The enzyme converts L-galactono-1,4-lactone to ascorbic acid (AA). In this work, the cloning and characterization...... of a GalLDH full-length cDNA from melon (Cucumis melo L.) are described. Melon genomic DNA Southern analysis indicated that CmGalLDH was encoded by a single gene. CmGalLDH mRNA accumulation was detected in all tissues studied, but differentially expressed during fruit development and seed germination......GalLDH expression is regulated by light. Finally, various stresses and growth regulators resulted in no significant change in steady state levels of CmGalLDH mRNA in 20-d-old melon seedlings. To the authors' knowledge, this is the first report of GalLDH transcript induction in seed germination and differential gene...

  11. 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

  12. Properties of acid casein gels made by acidification with Glucono-δ-lactone. 2. Syneresis, permeability and micro-structural properties

    NARCIS (Netherlands)

    Lucey, J.A.; Vliet, van T.; Grolle, K.; Geurts, T.; Walstra, P.

    1997-01-01

    Syneresis of casein gels made by acidification with glucono-δ-lactone (GDL) was studied in relation to gel structure as derived from permeametry and confocal scanning laser microscopy (CSLM). Gels made at 40 °C exhibited ‘spontaneous syneresis’ with wheying-off almost immediately after gelation, whi

  13. Design, synthesis, and biological evaluation of simplified analogues of (+)-discodermolide. Additional insights on the importance of the diene, the C7 hydroxyl, and the lactone.

    Science.gov (United States)

    Smith, Amos B; Xian, Ming

    2005-11-10

    [structure: see text] The design, synthesis, and biological evaluation of seven totally synthetic analogues of the antitumor agent (+)-discodermolide are reported. Saturation of the terminal diene system, alteration of the substituents on the lactone, and alkylation of the C7-hydroxyl group reveal significant structure-activity relationships.

  14. Elaboration of Sterically Hindered δ-Lactones through Ring-Closing Metathesis: Application to the Synthesis of the C1-C27 Fragment of Hemicalide.

    Science.gov (United States)

    Lecourt, Camille; Boinapally, Srikanth; Dhambri, Sabrina; Boissonnat, Guillaume; Meyer, Christophe; Cossy, Janine; Sautel, François; Massiot, Georges; Ardisson, Janick; Sorin, Geoffroy; Lannou, Marie-Isabelle

    2016-12-16

    The synthesis of the C1-C27 fragment of hemicalide, a marine metabolite displaying a unique potent antiproliferative activity, has been accomplished. The synthetic approach highlights a remarkably efficient ring-closing metathesis reaction catalyzed by Nolan ruthenium indenylidene complexes to elaborate the highly substituted δ-lactone framework.

  15. Genome sequence of Roseomonas sp. strain B5, a quorum-quenching N-acylhomoserine lactone-degrading bacterium isolated from Malaysian tropical soil.

    Science.gov (United States)

    Chen, Jian-Woon; Gan, Han Ming; Yin, Wai-Fong; Chan, Kok-Gan

    2012-12-01

    Roseomonas sp. strain B5 was isolated from Malaysian tropical soil that showed N-acylhomoserine lactone degradation. This is the first genome announcement of a member from the genus of Roseomonas and the first report on the quorum-quenching activity of Roseomonas spp.

  16. Genome Sequence of Roseomonas sp. Strain B5, a Quorum-Quenching N-Acylhomoserine Lactone-Degrading Bacterium Isolated from Malaysian Tropical Soil

    OpenAIRE

    Chen, Jian-Woon; Gan, Han Ming; Yin, Wai-Fong; Chan, Kok-Gan

    2012-01-01

    Roseomonas sp. strain B5 was isolated from Malaysian tropical soil that showed N-acylhomoserine lactone degradation. This is the first genome announcement of a member from the genus of Roseomonas and the first report on the quorum-quenching activity of Roseomonas spp.

  17. 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...

  18. Synaptic and blood-brain barrier structural changes in a rat epilepsy model induced by coriaria lacton

    Institute of Scientific and Technical Information of China (English)

    Jiyan Cheng; Jichun Huang; Yi Han; Guangyi Liu; Ling Yin; Furong Zheng

    2008-01-01

    BACKGROUND: Structural and functional synaptic changes, as well as blood-brain barrier (BBB) changes, affect the micro-environment of nervous tissue and excitation, both of which play an important role in epilepsy.OBJECTIVE: To observe synaptic and BBB ultrastructural changes in the motor cortex of a rat epilepsy model induced by coriaria lacton, and to investigate the synaptic and BBB effects on the mechanism of epilepsy.DESIGN: A randomized controlled animal experiment.SETTING: Department of Histology and Embryology, Luzhou Medical College; and Electron Microscopy Laboratory, Luzhou Medical College.MATERIALS: Twenty healthy male Sprague Dawley rats, aged 8 weeks, were chosen for this study. The rats weighed (280 ± 50) g and were supplied by the Experimental Animal Center of Luzhou Medical College. Experimentation was performed in accordance with the ethical guidelines for the use and care of animals. The animals were randomly divided into a control group and an epilepsy group, with 10 rats in each group. METHODS: This study was performed at the Department of Histology and Embryology, and Electron Microscopy Laboratory, Luzhou Medical College between February and December 2006. According to the protocol, the epilepsy group was injected with 10 μL/100 g coriaria lacton into the lateral ventricles to establish an epileptic model. The control group rats were not administered anything. Eight days after the model was established, all rats were anesthetized with ether. The motor cortex was removed and sectioned into ultrathin sections. Synaptic and BBB ultrastructural changes were observed by electron microscopy. MAIN OUTCOME MEASURES: ①Structural changes of three different parts of the synapses, synaptic cleft width, postsynaptic density thickness, proportion of perforation synapses, curvature of synaptic interface, and length of active zones. ②Capillary and BBB changes (endothelium, basement membrane, pericyte, and the astrocyte endfeet).RESULTS: ①Curvature of

  19. Genotoxic action of the sesquiterpene lactone glaucolide B on mammalian cells in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Regislaine V. Burim

    1999-09-01

    Full Text Available Glaucolide B is a sesquiterpene lactone isolated from Vernonia eremophila Mart. (Vernonieae, Asteraceae and has schistosomicidal, antimicrobial and analgesic activities. This study examined the cytotoxic and clastogenic activities of glaucolide B in human cultured lymphocytes and in bone marrow cells from BALB/c mice. The mitotic index (MI and chromosomal aberrations were analyzed in both of the above systems, whereas sister chromatid exchanges (SCE and the proliferation index (PI were determined only in vitro. In human cultured lymphocytes, glaucolide B concentrations greater than 15 µg/ml of culture medium completely inhibited cell growth. At 4 µg/ml and 8 µg/ml of culture medium, glaucolide B significantly increased the frequency of chromosomal aberrations in lymphocytes and was also cytotoxic at concentrations ³8 µg/ml; there was no increase in the frequency of SCE. Glaucolide B (160-640 mg/kg did not significantly increase the frequency of chromosomal aberrations in mouse bone marrow cells nor did it affect cell division. Since glaucolide B showed no clastogenic action on mammalian cells in vivo but was cytotoxic and clastogenic in vitro, caution is needed in its medicinal use.O glaucolido B é uma lactona sesquiterpênica, g-lactona a,b-insaturada, isolada da Vernonia eremophila Mart. (Vernonieae, Asteraceae; apresenta atividade esquistossomicida e antimicrobiana, além de atividade analgésica. A aceitação de uma substância para uso medicinal também depende de dados sobre sua toxicidade, além de sua eficiência medicinal. Assim, o objetivo deste trabalho foi testar a atividade clastogênica e citotóxica do composto glaucolido B in vitro e in vivo, utilizando linfócitos em cultura temporária e células da medula óssea de camundongos BALB/c, respectivamente. Analisaram-se o índice mitótico (MI e as aberrações cromossômicas nos sistemas in vitro e in vivo, e trocas entre cromátides irmãs (SCE e índice proliferativo (PI

  20. Synthesis of whisky lactone%威士忌内酯的合成研究

    Institute of Scientific and Technical Information of China (English)

    郭春生; 祖萌萌; 祁林; 王政; 张峻松

    2012-01-01

    With benzoyl peroxide and boric acid as catalyst,3 -methyl - 4 - oxooctanoic acid was synthesized by free radical addition reaction of valeraldehyde and crotonic acid as starting materials. Then it was reduced by sodium borohydride, and whisky lactone with cis and trans isomeric structure was obtained by intramolecular dehydration under the action of dilute sulfuric acid. The cis - trans isomers were separated by column chromatography,with eluent composed of V(petroleum ether): V(ethyl acetate) =5:1. Structure of the two targeted products were confirmed by IR,1HNMR and MS. Effect of factors on the yield such as kind of solvent, solvent amount, reaction time, dosage of sodium borohydride and dilute sulfuric acid were investigated. Optimum conditions for the reaction were found as follows:ethanol as solvent,m(ethanol): m(3 - methyl -4 -oxooctanoic acid) =3:1,reaction time 2 h at room temperature,m(sodium borohydride): m(3 -methyl -4 -oxooctanoic acid) = l:4;m(12% sulfuric acid): m(3 -methyl -4 - oxooctanoic acid) = 10: 1. Overall yield of the complete synthesis process achieves 61. 9%.%以过氧化苯甲酰和硼酸为催化剂,以戊醛和巴豆酸为起始原料经自由基加成反应合成了3-甲基-4-氧代辛酸,以硼氢化钠为还原剂和稀硫酸为脱水剂进行分子内脱水合成了顺反异构的威士忌内酯.以V(石油醚):V(乙酸乙酯)=5∶1的混合溶剂为洗脱剂,用柱层析法实现了威士忌内酯顺反异构体的分离.通过IR,1HNMR及MS确认了2种目标产物的结构.考察了溶剂、溶剂用量、反应时间、硼氢化钠用量和稀硫酸用量对目标产物收率的影响.最终的优化实验条件为:无水乙醇为溶剂,m(无水乙醇)∶m(3 -甲基-4-氧代辛酸)=3∶1,室温下反应2h,m(硼氢化钠)∶m(3-甲基-4-氧代辛酸)=1∶4,m(12%硫酸)∶m(3 -甲基-4-氧代辛酸)=10∶1,全合成的总收率为61.9%.

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

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    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

  2. Effect of Saccharides on Texture of Lactone Tofu%糖类对内酯豆腐质构的影响

    Institute of Scientific and Technical Information of China (English)

    于滨; 王喜波

    2012-01-01

    In this study, glucose, maltodextrin, soluble starch and carrageen were added to lactone tofu to study change of texture of lactone tofu. The results showed that saccharides type and concentration significantly affected different characteristics of lactone tofu. Glucose had greater impact on springness, maltodextrin on cohesiveness and adhesiveness ,soluble starch on hardness and chewiness,and carrageen on gumminess. Principal component analysis of SPSS indicated that the order of combined effect on texture of lactone tofu by four kinds of saccharides was as followed; carrageenan > soluble starch > glucose > maltodextrin. The molecular weight, structure and surface charge of saccharides were important factors affecting texture characteristics of lactone tofu.%为研究糖类对内酯豆腐的影响,向内酯豆腐中添加不同浓度的葡萄糖、麦芽糊精、可溶性淀粉和卡拉胶,并观察其质构的变化.结果表明,糖的种类和浓度对内酯豆腐的不同质构影响显著:葡萄糖对弹性影响较大,麦芽糊精对内聚性和黏性影响较大,可溶性淀粉对硬度和咀嚼性影响较大,卡拉胶对黏着力影响较大.SPSS主成分分析法研究表明,对内酯豆腐质构综合作用强弱顺序为卡拉胶>可溶性淀粉>葡萄糖>麦芽糊精.糖分子的分子质量、分子结构和表面电荷是影响内酯豆腐质构的重要因素.

  3. 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.

  4. Method to convert biomass to 5-(hydroxymethyl)-furfural (HMF) and furfural using lactones, furans, and pyrans as solvents

    Science.gov (United States)

    Dumesic, James A.; Ribeiro Gallo, Jean Marcel; Alonso, David

    2014-07-08

    Described is a process to produce hydroxymethyl furfural (HMF) from biomass-derived sugars. The process includes the steps of reacting a C5 and/or C6 sugar-containing reactant derived from biomass in a monophasic or biphasic reaction solution comprising water and a co-solvent. The co-solvent can be beta-, gamma-, and/or delta-lactones derived from biomass, tetrahydrofuran (THF) derived from biomass, and/or methyltetrahydrofuran (MTHF) derived from biomass. The reaction takes place in the presence of an acid catalyst and a dehydration catalyst for a time and under conditions such that at least a portion of glucose or fructose present in the reactant is converted to HMF.

  5. SF002-96-1, a new drimane sesquiterpene lactone from an Aspergillus species, inhibits survivin expression

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    Silke Felix

    2013-12-01

    Full Text Available Survivin, a member of the IAP (inhibitor of apoptosis gene family, is overexpressed in virtually all human cancers and is functionally involved in the inhibition of apoptosis, regulation of cell proliferation, metastasis and resistance to therapy. Because of its upregulation in malignancy, survivin has currently attracting considerable interest as a new target for anticancer therapy. In a screening of approximately 200 strains of imperfect fungi for the production of inhibitors of survivin promoter activity, a new drimane sesquiterpene lactone, SF002-96-1, was isolated from fermentations of an Aspergillus species. The compound inhibited survivin promoter activity in transiently transfected Colo 320 cells in a dose dependent manner with IC50 values of 3.42 µM (1.3 µg/mL. Moreover, it also reduced mRNA levels and protein synthesis of survivin and triggered apoptosis.

  6. Relative stereochemical determination and synthesis of the C17-C25 δ-lactone fragment of hemicalide.

    Science.gov (United States)

    Fleury, Etienne; Sorin, Geoffroy; Prost, Elise; Pancrazi, Ange; Sautel, François; Massiot, Georges; Lannou, Marie-Isabelle; Ardisson, Janick

    2013-02-01

    Hemicalide is a novel marine metabolite polyketide distinguished by a unique mechanism of action. Because of insufficient quantities of purified material, this natural product has evaded complete stereochemical assignments. Recently, we have determined the relative stereochemistry of the C8-C13 hexad by synthesizing the C1-C13 fragment. Presently, we report the assignment of the C17-C25 δ-lactone fragment. NMR analysis of authentic hemicalide along with a computational conformation study allowed us to reduce the number of putative relative isomers from 16 to 4. Concise syntheses of the four candidate diastereomers were achieved using a common strategy based on a Dias aldehyde allylation reaction, an intramolecular Horner-Wadsworth-Emmons olefination, and a dihydroxylation reaction. Finally, thorough NMR comparisons enabled us to deduce the relative stereochemistry of the C1-C17 fragment with high certainty.

  7. Sugar derivatives containing oxiranes and alpha,beta-unsaturated gamma-lactones as potential environmentally friendly insecticides.

    Science.gov (United States)

    Justino, Jorge; Rauter, Amélia P; Canda, Tana; Wilkins, Richard; Matthews, Elizabeth

    2005-10-01

    A range of novel sugar derivatives containing oxiranes or alpha,beta-unsaturated gamma-lactones in their structure were evaluated as potential insecticides with the added possible benefit of being benign in the environment. A number of arthropod species were chosen to represent those in the terrestrial, aerial and aquatic environments, covering target adult insects such as Musca domestica L (housefly) and Trialeurodes vaporariorum (Westwood) (glasshouse whitefly), which are public health and horticultural pests, Drosophila melanogaster Meig (fruitfly), both adult and larva, and a marine non-target crustacean, Artemia salina L. The tested compounds possessed efficacy and selectivity against these insect species, but were not toxic to brine shrimps, a reference organism in assays to evaluate the potential toxicity hazard to invertebrates in ecosystems.

  8. Andrographolide: A Novel Antimalarial Diterpene Lactone Compound from Andrographis paniculata and Its Interaction with Curcumin and Artesunate

    Science.gov (United States)

    Mishra, Kirti; Dash, Aditya P.; Dey, Nrisingha

    2011-01-01

    Andrographolide (AND), the diterpene lactone compound, was purified by HPLC from the methanolic fraction of the plant Andrographis paniculata. The compound was found to have potent antiplasmodial activity when tested in isolation and in combination with curcumin and artesunate against the erythrocytic stages of Plasmodium falciparum in vitro and Plasmodium berghei ANKA in vivo. IC50s for artesunate (AS), andrographolide (AND), and curcumin (CUR) were found to be 0.05, 9.1 and 17.4 μM, respectively. The compound (AND) was found synergistic with curcumin (CUR) and addictively interactive with artesunate (AS). In vivo, andrographolide-curcumin exhibited better antimalarial activity, not only by reducing parasitemia (29%), compared to the control (81%), but also by extending the life span by 2-3 folds. Being nontoxic to the in vivo system this agent can be used as template molecule for designing new derivatives with improved antimalarial properties. PMID:21760808

  9. Andrographolide: A Novel Antimalarial Diterpene Lactone Compound from Andrographis paniculata and Its Interaction with Curcumin and Artesunate

    Directory of Open Access Journals (Sweden)

    Kirti Mishra

    2011-01-01

    Full Text Available Andrographolide (AND, the diterpene lactone compound, was purified by HPLC from the methanolic fraction of the plant Andrographis paniculata. The compound was found to have potent antiplasmodial activity when tested in isolation and in combination with curcumin and artesunate against the erythrocytic stages of Plasmodium falciparum in vitro and Plasmodium berghei ANKA in vivo. IC50s for artesunate (AS, andrographolide (AND, and curcumin (CUR were found to be 0.05, 9.1 and 17.4 μM, respectively. The compound (AND was found synergistic with curcumin (CUR and addictively interactive with artesunate (AS. In vivo, andrographolide-curcumin exhibited better antimalarial activity, not only by reducing parasitemia (29%, compared to the control (81%, but also by extending the life span by 2-3 folds. Being nontoxic to the in vivo system this agent can be used as template molecule for designing new derivatives with improved antimalarial properties.

  10. Interactions of a family 18 chitinase with the designed inhibitor HM508 and its degradation product, chitobiono-delta-lactone.

    Science.gov (United States)

    Vaaje-Kolstad, Gustav; Vasella, Andrea; Peter, Martin G; Netter, Catharina; Houston, Douglas R; Westereng, Bjørge; Synstad, Bjørnar; Eijsink, Vincent G H; van Aalten, Daan M F

    2004-01-30

    We describe enzymological and structural analyses of the interaction between the family 18 chitinase ChiB from Serratia marcescens and the designed inhibitor N,N'-diacetylchitobionoxime-N-phenylcarbamate (HM508). HM508 acts as a competitive inhibitor of this enzyme with a K(i) in the 50 microM range. Active site mutants of ChiB show K(i) values ranging from 1 to 200 microM, providing insight into some of the interactions that determine inhibitor affinity. Interestingly, the wild type enzyme slowly degrades HM508, but the inhibitor is essentially stable in the presence of the moderately active D142N mutant of ChiB. The crystal structure of the D142N-HM508 complex revealed that the two sugar moieties bind to the -2 and -1 subsites, whereas the phenyl group interacts with aromatic side chains that line the +1 and +2 subsites. Enzymatic degradation of HM508, as well as a Trp --> Ala mutation in the +2 subsite of ChiB, led to reduced affinity for the inhibitor, showing that interactions between the phenyl group and the enzyme contribute to binding. Interestingly, a complex of enzymatically degraded HM508 with the wild type enzyme showed a chitobiono-delta-lactone bound in the -2 and -1 subsites, despite the fact that the equilibrium between the lactone and the hydroxy acid forms in solution lies far toward the latter. This shows that the active site preferentially binds the (4)E conformation of the -1 sugar, which resembles the proposed transition state of the reaction.

  11. 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.

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

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    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.

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

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    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.

  14. A review on the toxicity and non-target effects of macrocyclic lactones in terrestrial and aquatic environments.

    Science.gov (United States)

    Lumaret, Jean-Pierre; Errouissi, Faiek; Floate, Kevin; Römbke, Jörg; Wardhaugh, Keith

    2012-05-01

    The avermectins, milbemycins and spinosyns are collectively referred to as macrocyclic lactones (MLs) which comprise several classes of chemicals derived from cultures of soil micro-organisms. These compounds are extensively and increasingly used in veterinary medicine and agriculture. Due to their potential effects on non-target organisms, large amounts of information on their impact in the environment has been compiled in recent years, mainly caused by legal requirements related to their marketing authorization or registration. The main objective of this paper is to critically review the present knowledge about the acute and chronic ecotoxicological effects of MLs on organisms, mainly invertebrates, in the terrestrial and aquatic environment. Detailed information is presented on the mode-of-action as well as the ecotoxicity of the most important compounds representing the three groups of MLs. This information, based on more than 360 references, is mainly provided in nine tables, presenting the effects of abamectin, ivermectin, eprinomectin, doramectin, emamectin, moxidectin, and spinosad on individual species of terrestrial and aquatic invertebrates as well as plants and algae. Since dung dwelling organisms are particularly important non-targets, as they are exposed via dung from treated animals over their whole life-cycle, the information on the effects of MLs on dung communities is compiled in an additional table. The results of this review clearly demonstrate that regarding environmental impacts many macrocyclic lactones are substances of high concern particularly with larval instars of invertebrates. Recent studies have also shown that susceptibility varies with life cycle stage and impacts can be mitigated by using MLs when these stages are not present. However information on the environmental impact of the MLs is scattered across a wide range of specialised scientific journals with research focusing mainly on ivermectin and to a lesser extent on abamectin

  15. Weak and saturable protein-surfactant interactions in the denaturation of apo-alpha-lactalbumin by acidic and lactonic sophorolipid

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    Kell K Andersen

    2016-11-01

    Full Text Available Biosurfactants are of growing interest as sustainable alternatives to fossil-fuel-derived chemical surfactants, particularly for the detergent industry. To realize this potential, it is necessary to understand how they affect proteins which they may encounter in their applications. However knowledge of such interactions is limited. Here we present a study of the interactions between the model protein apo-alpha-lactalbumin and the biosurfactant sophorolipid (SL produced by the yeast Starmerella bombicola. SL occurs both as an acidic and a lactonic form; the lactonic form (lactSL is sparingly soluble and has a lower critical micelle concentration than the acidic form (acidSL. We show that acidSL affects apo-aLA in a similar way to the related glycolipid biosurfactant rhamnolipid (RL, with the important difference that RL is also active below the cmc in contrast to acidSL. Using isothermal titration calorimetry data, we show that acidSL has weak and saturable interactions with apo-aLA at low concentrations; due to the relatively low cmc of acidSL (which means that the monomer concentration is limited to ca. 0-1 mM SL, it is only possible to observe interactions with monomeric acidSL at high apo-aLA concentrations. However, the denaturation kinetics of apo-aLA in the presence of acidSL are consistent with a collaboration between monomeric and micellar surfactant species, similar to RL and nonionic or zwitterionic surfactants. Inclusion of lactSL as mixed micelles with acidSL lowers the cmc and this effectively reduces the rate of unfolding, emphasizing that SL like other biosurfactants is a gentle anionic surfactant. Our data highlight the potential of these biosurfactants for future use in the detergent industry.

  16. Biogenic guaianolide-type sesquiterpene lactones with antioxidative and anti-inflammatory properties from natural mangrove hybrid Rhizophora annamalayana.

    Science.gov (United States)

    Raola, Vamshi Krishna; Chakraborty, Kajal

    2017-02-24

    Previously undescribed guaianolide-type sesquiterpene lactones were isolated from the chloroform fraction of the natural hybrid mangrove Rhizophora annamalayana, and were characterised as (Z)-3α,4,5,6-tetrahydro-5α-isobutyl-2β-(methoxymethyl)-7-methyl-3H-cyclohepta[b]carbolactone (1) and (7Z)-isopentyl 3α,4,5,6,7,8-hexahydro-2β-((E)-11-methylbut-10-enyl)-1-oxo-2H-cyclohepta[b]furan-6-carboxylate (2). Compound 2 displayed greater antioxidative activities {1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2'-azino-bis-3 ethylbenzothiozoline-6-sulphonic acid diammonium salt (ABTS), IC50 0.65 and 0.62 mg/mL, respectively)} compared to 1 (IC50 0.83 and 1.14 mg/mL, respectively) (p < 0.05). Compound 2 recorded no significant difference in DPPH(.) scavenging activities (IC50 0.65 mg/mL) compared to α-tocopherol (IC50 0.63 mg/mL). Pro-inflammatory 5-lipoxygenase inhibitory activity of 2 was found to be comparable (IC50 0.98 mg/mL) to that displayed by synthetic anti-inflammatory drug ibuprofen (IC50 0.93 mg/mL). Compound 2 showed significantly greater selectivity index (anti-cyclooxygenase-1/anti-cyclooxygenase-2 = 2.15) than non-steroidal anti-inflammatory ibuprofen (<0.5) (p < 0.05), and therefore, might be used as selective cyclooxygenase-2 inhibitor. The hitherto undescribed guaianolide lactones might be used as potential anti-inflammatory and antioxidative pharmacophore leads.

  17. Highly Oxygenated Sesquiterpene Lactones from Cousinia aitchisonii and their Cytotoxic Properties: Rhaserolide Induces Apoptosis in Human T Lymphocyte (Jurkat) Cells via the Activation of c-Jun n-terminal Kinase Phosphorylation.

    Science.gov (United States)

    Iranshahy, Milad; Tayarani-Najaran, Zahra; Kasaian, Jamal; Ghandadi, Morteza; Emami, Seyed Ahmad; Asili, Javad; Chandran, Jima N; Schneider, Bernd; Iranshahi, Mehrdad

    2016-02-01

    Infrared-guided chromatographic fractionation of sesquiterpene lactones from the extracts of Cousinia aitchisonii and Cousinia concolor led to the isolation of five pure compounds. A new sesquiterpene lactone, namely, aitchisonolide, and two known sesquiterpene lactones (desoxyjanerin and rhaserolide) were isolated from C. aitchisonii and two known lignans (arctiin and arctigenin) from C. concolor. The structures of these compounds were elucidated by one-dimensional and two-dimensional nuclear magnetic resonance techniques, as well as high-resolution mass spectrometry. The purified and characterized compounds were subjected to cytotoxicity assay. The sesquiterpene lactones desoxyjanerin and rhaserolide showed significant cytotoxic activities against five different cancer cell lines and the normal human embryonic kidney cell line. Rhaserolide was chosen to evaluate the possible mechanism of action. Western blot analysis revealed that rhaserolide could induce apoptosis in Jurkat cells via the activation of c-Jun n-terminal kinase phosphorylation.

  18. Determining the Degree of Anthelmintic Resistance against Macrocyclic Lactones in Small Strongylus, Based on the Larvae Development Analysis (LDA in Horses from Grasslands in the Department of Casanare

    Directory of Open Access Journals (Sweden)

    Germán Alonso Prada

    2011-06-01

    Full Text Available This study was conducted in the grasslands of the Department of Casanare, seeking to determine the degree of anthelmintic susceptibility or resistance against macrocyclic lactones in small populations of Strongylus in this region of the country. Samples were taken from four municipalities in the department: Aguazul, Paz de Ariporo, Maní and El Yopal, between June, 2006 and April, 2007, where ten fresh fecal samples were collected in each municipality, directly from the field and in a completely random way. The samples were processed using the MacMaster coprological technique, thus determining the highest count of fecal epg by municipality. L3 larvae were extracted from each of the six samples with the highest count of fecal epg through the coprological and Baermann-Wetzel tests with which the Larvae Development Analysis (LDA test was run, detecting Small Strongylus highly susceptible to the action of macrocyclic lactones (ivermectin.

  19. Scientific Opinion on the safety and efficacy of primary aliphatic saturated or unsaturated alcohols/aldehydes/acids/acetals/esters with a second primary, secondary or tertiary oxygenated functional group including aliphatic lactones (chemical group 9 when used as flavourings for all animal species

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2012-10-01

    Full Text Available

    Chemical group 9 consists of primary aliphatic saturated or unsaturated alcohols/aldehydes/acids/acetals/esters with a second primary, secondary or tertiary oxygenated functional group including aliphatic lactones, of which 30 are currently authorised for use as flavours in food. The FEEDAP Panel was unable to perform an assessment of 2-oxopropanal because of issues related to the purity of the compound. The FEEDAP Panel concludes that lactic acid, succinic acid, fumaric acid, 4-oxovaleric acid, ethyl lactate, butyl lactate, butyl-O-butyryllactate, hex-3-enyl lactate, hexyl lactate, ethyl acetoacetate, ethyl 4-oxovalerate, diethylsuccinate and diethyl malonate are considered to be safe for all animal species at the use levels proposed when used as feed flavourings; octano-1,4-lactone, nonano-1,4-lactone, decano-1,4-lactone and undecano-1,4-lactone are safe at 20 mg/kg complete feed; butyro-1,4-lactone, pentano-1,4-lactone, hexano-1,4-lactone, heptano-1,4-lactone, octano-1,5-lactone, nonano-1,5-lactone, decano-1,5-lactone and undecano-1,5-lactone at 5 mg/kg complete feed; dodecano-1,4-lactone, dodecano-1,5-lactone, tetradecano-1,5-lactone, and pentadecano-1,15-lactone at a maximum of 1.5 mg/kg complete feed for cattle, salmonids and non food producing animals and of 1 mg/kg complete feed for pigs and poultry. No safety concern was identified for the consumer from the use of compounds belonging to CG 9 up to the highest safe level in feedingstuffs for all animal species. All compounds should be considered as irritants to skin, eyes and respiratory tract, and as skin sensitizers. The compounds do not pose a risk to the environment when used at concentrations considered safe for the target species. Since all compounds are used in food as flavourings, no further demonstration of efficacy is necessary.

  20. Pharmacokinetics and tissue distribution of ginkgolide A, ginkgolide B, and ginkgolide K after intravenous infusion of ginkgo diterpene lactones in a rat model.

    Science.gov (United States)

    Wang, Shuyao; Ouyang, Bingchen; Aa, Jiye; Geng, Jianliang; Fei, Fei; Wang, Pei; Wang, Jiankun; Peng, Ying; Geng, Ting; Li, Yanjing; Huang, Wenzhe; Wang, Zhenzhong; Xiao, Wei; Wang, Guangji

    2016-07-15

    Ginkgo diterpene lactones are compounds that are extracted from the Ginkgo biloba leaf and possess pharmacologic activities with neuroprotective effects. To address the poor bioavailability of ginkgo diterpene lactones, ginkgo diterpene lactone meglumine injection (GDLI) was formulated and is commercially available. In this study, a simple, sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for assessing the total amount and the amount of the prototype forms of ginkgolides A (GA), B (GB) and K (GK) in rat plasma and tissues. This method was used to calculate the concentrations of the hydrolysed carboxylic forms and assess the pharmacokinetics of the ginkgolides after intravenous (i.v.) GDLI administration in rats. Generally, all three ginkgolide forms showed dose-dependent plasma concentrations, and no obvious differences in pharmacokinetic parameters, i.e., area under the curve (AUC) of plasma concentration versus time and half-life, were observed after GDLI administration on 7 consecutive days. These ginkgolides primarily existed in the carboxylic form in the plasma, and the systemic concentrations of the carboxylic forms of GA and GB were 11- to 17- and 3- to 4-fold higher than those of their prototype forms, respectively. In contrast, dramatically increased levels of the GA and GB prototype lactones were detected in the liver and heart. GA, GB, and GK were extensively distributed in various organs/tissues; the highest levels were found in the kidneys, liver, and intestine, and the lowest levels were found in the brain. These data suggest that ginkgolides have difficulty crossing the blood-brain barrier and that their targets for protecting against cerebral ischaemia are located outside the central system.

  1. Practical and concise synthesis of 2-oxo-3,4,5,6-tetraethoxyazepane from D-glucono-1,5-lactone

    Institute of Scientific and Technical Information of China (English)

    Yan Jiao; Zhi Jie Fang; Yu Hua Jiang; Bao Hui Zheng; Jie Cheng

    2008-01-01

    2-Oxo-3R,4S,5S,6S-tetraethoxyazepane was conveniently synthesized from D-glucono-1,5-lactone with a yield of 10% overall.The key step of synthetic route-reductive 1,6-cyclization was completed efficiently by using Ph3P to give the expected lactam.(c)2008 Zhi Jie Fang.Published by Elsevier B.V.on behalf of Chinese Chemical Society.All rights reserved.

  2. Sesquiterpene Lactone Composition and Cellular Nrf2 Induction of Taraxacum officinale Leaves and Roots and Taraxinic Acid β-d-Glucopyranosyl Ester.

    Science.gov (United States)

    Esatbeyoglu, Tuba; Obermair, Betina; Dorn, Tabea; Siems, Karsten; Rimbach, Gerald; Birringer, Marc

    2017-01-01

    Taraxacum officinale, the common dandelion, is a plant of the Asteraceae family, which is used as a food and medical herb. Various secondary plant metabolites such as sesquiterpene lactones, triterpenoids, flavonoids, phenolic acids, coumarins, and steroids have been described to be present in T. officinale. Dandelion may exhibit various health benefits, including antioxidant, anti-inflammatory, and anticarcinogenic properties. We analyzed the leaves and roots of the common dandelion (T. officinale) using high-performance liquid chromatography/mass spectrometry to determine its sesquiterpene lactone composition. The main compound of the leaf extract taraxinic acid β-d-glucopyranosyl ester (1), a sesquiterpene lactone, was isolated and the structure elucidation was conducted by nuclear magnetic resonance spectrometry. The leaf extract and its main compound 1 activated the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in human hepatocytes more significantly than the root extract. Furthermore, the leaf extract induced the Nrf2 target gene heme oxygenase 1. Overall, present data suggest that compound 1 may be one of the active principles of T. officinale.

  3. 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

  4. 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.

  5. 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.

  6. Alkali-hydrolysis of D-glucono-delta-lactone studied by chiral Raman and circular dichroism spectroscopies

    Institute of Scientific and Technical Information of China (English)

    JIA GuoQing; QIU Shi; LI GuanNa; ZHOU Jun; FENG ZhaoChi; LI Can

    2009-01-01

    The alkali-hydrolysis of D-glucono-delta-lactone (GDL) was investigated by chiral Raman and circular dichroism (CD) spectroecopies in combination with density functional theory calculation. Based on the characteristic CD bands of GDL and its hydrolysis product, the dynamics of hydrolysis was studied using stopped-flow CD method. Using chiral Raman spectroscopy (CRS), the stereochemical change of GDL owing to the hydrolysis reaction was discussed on the vibrational scale. The CRS results show that the ring-opening due to hydrolysis has a great influence on the chiral structure around the cer-bonyl group, which was evidenced by the disappearance of the CRS band at 1735 cm-1 (C=0 stretching vibrational mode). In addition, the change of positions and intensity of CRS bands was also observed, which was ascribed to the perturbation around the C2, C3, C4 and C5 carbons due to ring-opening. It is worthy to note that the stereochemistry of C2, C3, C4 and C5 had no fundamental change during the hydrolysis reaction, which was reflected in the maintenance of the signs of the CRS bands. Our results demonstrate that in comparison with CD technique, CRS may provide more detailed structural infor-mation of chiral molecules and open up new vistas of research for chirel reactions.

  7. Alkali-hydrolysis of D-glucono-delta-lactone studied by chiral Raman and circular dichroism spectroscopies

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The alkali-hydrolysis of D-glucono-delta-lactone (GDL) was investigated by chiral Raman and circular dichroism (CD) spectroscopies in combination with density functional theory calculation. Based on the characteristic CD bands of GDL and its hydrolysis product, the dynamics of hydrolysis was studied using stopped-flow CD method. Using chiral Raman spectroscopy (CRS), the stereochemical change of GDL owing to the hydrolysis reaction was discussed on the vibrational scale. The CRS results show that the ring-opening due to hydrolysis has a great influence on the chiral structure around the car-bonyl group, which was evidenced by the disappearance of the CRS band at 1735 cm-1 (C== O stretching vibrational mode). In addition, the change of positions and intensity of CRS bands was also observed, which was ascribed to the perturbation around the C2, C3, C4 and C5 carbons due to ring-opening. It is worthy to note that the stereochemistry of C2, C3, C4 and C5 had no fundamental change during the hydrolysis reaction, which was reflected in the maintenance of the signs of the CRS bands. Our results demonstrate that in comparison with CD technique, CRS may provide more detailed structural information of chiral molecules and open up new vistas of research for chiral reactions.

  8. 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.

  9. 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...

  10. Effect of Coriaria Lactone-activated Astrocyte-conditioned Medium on the Cerebral TNF-α of Normal Rats

    Institute of Scientific and Technical Information of China (English)

    LI Zhongyu; LIU Qingying; ZHU Changgeng; WANG Wei

    2006-01-01

    To explore the effect of coriaria lactone (CL)-activated astrocyte-conditioned medium on the cerebral TNF-α of normal rats, the CL-activated astrocyte-conditioned medium (ACM) was injected into the lateral ventricle of SD rats. The rats were observed for behavioral changes, and the changes of the expression of TNF-α in the cerebral cortex and hippocampus were immunohistochemically examined by employing SP method. TNF-α level was assessed by means of radioimmunoassay in homogenate of cerebral cortex and hippocampus as well as cerebrospinal fluid. Seizure episodes were observed in ACM group 30 min after the ACM injection, but they were not observed in the control group.Immunohistochemical detection showed that the immunoreaction of TNF-α in hippocampus and cerebral cortex of rats were stronger than that of the control group 4 h after the ACM injection (P<0.05). In this group, the concentrations of TNF-α in homogenate of cerebral cortex and hippocampus and cerebrospinal fluid were higher than those of the control group (P<0.05). Itis suggested that the ACM activated by CL can enhance the expression of TNF-α in normal rats,and is related to epileptogenesis.

  11. Macrocyclic lactone resistance in Dirofilaria immitis: Failure of heartworm preventives and investigation of genetic markers for resistance.

    Science.gov (United States)

    Bourguinat, Catherine; Lee, Alice C Y; Lizundia, Regina; Blagburn, Byron L; Liotta, Janice L; Kraus, Marc S; Keller, Kathy; Epe, Christian; Letourneau, Louis; Kleinman, Claudia L; Paterson, Tara; Gomez, Elena Carreton; Montoya-Alonso, José Alberto; Smith, Hubert; Bhan, Aron; Peregrine, Andrew S; Carmichael, James; Drake, Jason; Schenker, Rudolf; Kaminsky, Ronald; Bowman, Dwight D; Geary, Timothy G; Prichard, Roger K

    2015-06-15

    Macrocyclic lactone (ML) endectocides are used as chemoprophylaxis for heartworm infection (Dirofilaria immitis) in dogs and cats. Claims of loss of efficacy (LOE) of ML heartworm preventives have become common in some locations in the USA. We directly tested whether resistance to MLs exists in LOE isolates of D. immitis and identified genetic markers that are correlated with, and therefore can predict ML resistance. ML controlled studies showed that LOE strains of D. immitis established infections in dogs despite chemoprophylaxis with oral ivermectin or injectable moxidectin. A whole genome approach was used to search for loci associated with the resistance phenotype. Many loci showed highly significant differences between pools of susceptible and LOE D. immitis. Based on 186 potential marker loci, Sequenom(®) SNP frequency analyses were conducted on 663 individual parasites (adult worms and microfilariae) which were phenotypically characterized as susceptible (SUS), confirmed ML treatment survivors/resistant (RES), or suspected resistant/loss of efficacy (LOE) parasites. There was a subset of SNP loci which appears to be promising markers for predicting ML resistance, including SNPs in some genes that have been associated with ML resistance in other parasites. These data provide unequivocal proof of ML resistance in D. immitis and identify genetic markers that could be used to monitor for ML resistance in heartworms.

  12. Aggregation of soy protein-isoflavone complexes and gel formation induced by glucono-δ-lactone in soymilk

    Science.gov (United States)

    Hsia, Sheng-Yang; Hsiao, Yu-Hsuan; Li, Wen-Tai; Hsieh, Jung-Feng

    2016-10-01

    This study investigated the glucono-δ-lactone (GDL)-induced aggregation of isoflavones and soy proteins in soymilk. High-performance liquid chromatography (HPLC) analysis indicated that isoflavones mixed with β-conglycinin (7S) and glycinin (11S) proteins formed 7S-isoflavone and 11S-isoflavone complexes in soymilk supernatant fraction (SSF). Most of the soy protein-isoflavone complexes then precipitated into the soymilk pellet fraction (SPF) following the addition of 4 mM GDL, whereupon the pH value of the soymilk dropped from 6.6 to 5.9. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and HPLC analysis suggest that the addition of 4 mM GDL induced the aggregation of most 7S (α’, α and β subunits), 11S acidic and 11S basic proteins as well as isoflavones, including most aglycones, including daidzein, glycitein, genistein and a portion of glucosides, including daidzin, glycitin, genistin, malonyldaidzin and malonylgenistin. These results provide an important reference pertaining to the effects of GDL on the aggregation of soy protein-isoflavone complexes and could benefit future research regarding the production of tofu from soymilk.

  13. Structure-activity relationships for the hypertensinogenic activity of ouabain: role of the sugar and lactone ring.

    Science.gov (United States)

    Manunta, P; Hamilton, B P; Hamlyn, J M

    2001-02-01

    Elevated levels of an endogenous ouabain circulate in many patients with essential hypertension. However, in contrast to ouabain, digoxin does not induce hypertension. This study investigated the hypothesis that within a single cardiac glycoside, the structural elements that induce hypertension differ from those responsible for high potency as a sodium pump inhibitor. Normal male Sprague-Dawley rats received infusions of vehicle (VEH), rhamnose (RHA), ouabain (OUA), ouabagenin (OGN), dihydro-ouabain (DHO), iso-ouabain (ISO), and a lactone ring opened analog (ORO) at 30 microgram. kg(-1). 24 h(-1) for 5 weeks via subcutaneous osmotic pumps. Cuff pressures were taken weekly. At the end of the study, trunk blood was harvested, extracted by C18 column, and subjected to high-performance liquid chromatography. Fractions were analyzed for OUA, OGN, and DHO by immunoassay. In OUA-, OGN-, and DHO-infused rats, 1 main peak of immunoreactivity corresponding to the infused agent was found. No evidence of in vivo conversion to OUA or DHO was found for any analog except ORO. At 5 weeks, systolic blood pressures in VEH, RHA, OUA, OGN, DHO, ISO, and ORO were 132+/-2.5, 133+/-1.5, 159+/-2.6,* 154+/-4,* 167+/-4,* 171+/-2.2,* and 169+/-2.4* mm Hg, respectively (*Pmechanism of action independent of the sodium pump.

  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. Influences of "spasmolytic powder" on pgp expression of Coriaria Lactone-kindling drug-resistant epileptic rat model.

    Science.gov (United States)

    Chen, Lei; Feng, Peimin; Li, Yaohua; Zhou, Dong

    2013-09-01

    The earliest records of traditional Chinese medicine (TCM) prevention and treatment of epilepsy dated back to famous "Huang Di Nei Jing." TCM "spasmolytic powder" (equal-ratio compatibility of scorpion and centipede) is a famous prescription which was recognized as a useful add-on drug for refractory epilepsy in clinical observations. Multidrug resistance gene (mdr1) product Pgp overexpression in blood-brain barrier and blood-cerebrospinal fluid barrier is well recognized as the drug resistance mechanism of refractory epilepsy. Here, we established the drug-resistant epilepsy Sprague-Dawley rat model induced by Coriaria Lactone and treated these rats with topiramate and verapamil and low dose, middle dose, and high dose of spasmolytic powder by intragastric administration for 1 week. Electroencephalogram, real-time PCR, and immunohistochemistry were respectively used to detect epileptic discharge frequencies and amplitudes and expression of mdrl mRNA and Pgp on hippocampus and temporal lobe of rats. The results showed that the seizure decreases significantly in the high- and middle-dose groups of spasmolytic powder and topiramate group; in addition, mdr1 mRNA and Pgp expressions on hippocampus and temporal lobe of these drug intervention groups were significantly less than the model group (P < 0.05). These findings indicate that inhibition of intracephalic Pgp expression is possibly one of mechanisms of spasmolytic powder treating refractory epilepsy.

  16. Quantitative HPLC analysis of sesquiterpene lactones and determination of chemotypes in Eremanthus seidelii MacLeish and Schumacher (Asteraceae)

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Humberto T. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Quimica; Gobbo-Neto, Leonardo; Lopes, Norberto P.; Lopes, Joao L.C. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas. Dept. de Fisica e Quimica]. E-mail: joaoluis@usp.br; npelopes@fcfrp.usp.br; Cavalheiro, Alberto J. [UNESP, Araraquara, SP (Brazil). Inst. de Quimica

    2005-11-15

    anthus seidelii MacLeish and Schumacher has a restricted occurrence to the Brazilian 'cerrado' surrounding the Furnas (MG) reservoir, in environments that have been seriously damaged by human activity. The present phytochemical investigation reveals that the sesquiterpene lactones (SL) 4{beta},5-dihydro-2',3'-dihydroxy-15-desoxy-goyazensolide (1) and 4{beta},5-dihydro-1',2'-epoxy-eremantholide-C (2) are the major secondary metabolites in E. seidelii leaves, and an HPLC method was developed for their quantitative analysis. HPLC analysis showed no significant seasonal variation in the concentrations of both SL. No qualitative differences were found in the SL patterns of all individuals sampled. However, there is a different SL quantitative pattern among the plants analyzed, pointing to the existence of three quantitative chemotypes of this species, with differences possibly originating from the activity of the enzymes that cyclize the goyazensolide type SL (1) to a eremantholide type SL (2). (author)

  17. Structure-activity relationships for the irreversible blockade of nicotinic receptor agonist sites by lophotoxin and congeneric diterpene lactones

    Energy Technology Data Exchange (ETDEWEB)

    Culver, P.; Burch, M.; Potenza, C.; Wasserman, L.; Fenical, W.; Taylor, P.

    1985-11-01

    Lophotoxin, a diterpene lactone paralytic toxin from gorgonian corals of the genus Lophogorgia, inhibits ( SVI)-alpha-toxin binding to surface nicotinic receptors of BC3H-1 cells by irreversible occupation of the primary agonist sites. In contrast, receptor-bearing membrane fragments or detergent-solubilized receptors prepared from BC3H-1 cells are not susceptible to lophotoxin block. Thus, lophotoxin inhibition requires intact cells. However, when intact cells were incubated with lophotoxin, subsequent membrane-fragment preparation or detergent solubilization of the receptors did not diminish lophotoxin occupation of ( SVI)-alpha-toxin-binding sites, indicating that lophotoxin binds very tightly to nicotinic receptors. These studies further demonstrate that both surface and nonsurface nicotinic receptors of BC3H-1 cells are susceptible to irreversible occupation by lophotoxin, indicating that the lipophilic toxin freely permeates intact cells. The authors also examined several structural analogs of lophotoxin, one of which was equipotent with lophotoxin for inhibition of ( SVI)-alpha-toxin binding to intact cells and, notably, also blocked alpha-toxin binding to detergent-extracted receptor.

  18. 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.

  19. Synthesis of Gold Mediated Biocompatible Nanocomposite of Lactone Enriched Fraction from Sahadevi (Vernonia cinerea Lees): An Assessment of Antimalarial Potential.

    Science.gov (United States)

    Jyotshna; Shanker, Karuna; Khare, Puja; Tiwari, Nimisha; Mohanty, Shilpa; Bawankule, Dnyaneshwar U; Pal, Anirban

    2016-01-01

    Metals reduction into submicro/nano size through bhasma preparations for therapeutic use is well established in ancient traditional system of Indian medicines i.e. Ayurveda. Recently, nanotechnology has drawn the attention of researchers to develeope various size and shape nanoparicles / composite for number of applications.In this article, we report the enrichment of lactone enriched fraction (LEF) by liquid-liquid portioning of Vernonia cinerea metabolic extract and sysnthesis of mediated nano-gold composite (LEF-AuNPs) in single step process. The morphological characteristic based on transmission electron microscope (TEM) image analysis showed that LEF-AuNPs were predominantly nanopolygons and nanobots in shapes ranging from 50-200 nm in size. Abundance of phytochemicals in both LEF and LEF-AuNPs was dissimilar. In LEF, montanol- a diterpenoid, while in LEF-AuNPs, neophytadiene- a phytanes was the major compound. HPLC profile of relatively polar compounds also varied drastically. In-vitro biocompatibility, cytotoxicity [MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) based assay] and storage stabilitiy of LEF-AuNPs were evaluated. The moderate ability of LEF-AuNPs to restrict parasitaemia, extended mean survival time of mice infected with Plasmodium berghei and lack of any evident toxicity provides new opportunities for the safe delivery and applications of such nanocomposites in malaria therapy.

  20. Total syntheses of the phytotoxic lactones herbarumin I and II and a synthesis-based solution of the pinolidoxin puzzle.

    Science.gov (United States)

    Fürstner, Alois; Radkowski, Karin; Wirtz, Conny; Goddard, Richard; Lehmann, Christian W; Mynott, Richard

    2002-06-19

    A concise approach to a family of potent herbicidal 10-membered lactones is described on the basis of ring-closing metathesis (RCM) as the key step for the formation of the medium-sized ring. This includes the first total syntheses of herbarumin I (1) and II (2) as well as the synthesis of several possible macrolides of the pinolidoxin series. A comparison of their spectral and analytical data with those of the natural product allowed us to establish the stereostructure of pinolidoxin, a potent inhibitor of induced phenylalanine ammonia lyase (PAL) activity, as shown in 46. This finding, however, makes clear that a previous study dealing with the relative and absolute stereochemistry of this phytotoxic agent cannot be correct. An important aspect from the preparative point of view is the fact that the stereochemical outcome of the RCM reaction can be controlled by the choice of the catalyst. Thus, use of the ruthenium indenylidene complex 16 always leads to the corresponding (E)-alkenes, whereas the second generation catalyst 17 bearing an N-heterocyclic carbene ligand affords the isomeric (Z)-olefin with good selectivity. This course is deemed to reflect kinetic versus thermodynamic control of the cyclization reaction and therefore has potentially broader ramifications for the synthesis of medium-sized rings in general. A further noteworthy design feature is the fact that D-ribose is used as a convenient starting material for the preparation of both enantiomers of the key building block 14 by means of a "head-to-tail" interconversion strategy.

  1. 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.

  2. Investigating a possible role for the bacterial signal molecules N-acylhomoserine lactones in Balanus improvisus cyprid settlement.

    Science.gov (United States)

    Tait, Karen; Havenhand, Jon

    2013-05-01

    Increased settlement on bacterial biofilms has been demonstrated for a number of marine invertebrate larvae, but the nature of the cue(s) responsible is not well understood. We tested the hypothesis that the bay barnacle Balanus improvisus utilizes the bacterial signal molecules N-acylhomoserine lactones (AHLs) as a cue for the selection of sites for permanent attachment. Single species biofilms of the AHL-producing bacteria Vibrio anguillarum, Aeromonas hydrophila and Sulfitobacter sp. BR1 were attractive to settling cypris larvae of B. improvisus. However, when AHL production was inactivated, either by mutation of the AHL synthetic genes or by expression of an AHL-degrading gene (aiiA), the ability of the bacteria to attract cyprids was abolished. In addition, cyprids actively explored biofilms of E. coli expressing the recombinant AHL synthase genes luxI from Vibrio fischeri (3-oxo-C6-HSL), rhlI from Pseudomonas aeruginosa (C4-HSL/C6-HSL), vanI from V. anguillarum (3-oxo-C10-HSL) and sulI from Sulfitobacter sp. BR1 (C4-HSL, 3-hydroxy-C6-HSL, C8-HSL and 3-hydroxy-C10-HSL), but not E. coli that did not produce AHLs. Finally, synthetic AHLs (C8-HSL, 3-oxo-C10-HSL and C12-HSL) at concentrations similar to those found within natural biofilms (5 μm) resulted in increased cyprid settlement. Thus, B. improvisus cypris exploration of and settlement on biofilms appears to be mediated by AHL-signalling bacteria in the laboratory. This adds to our understanding of how quorum sensing inhibition may be used as for biofouling control. Nonetheless, the significance of our results for larvae settling naturally in the field, and the mechanisms that underlay the observed responses to AHLs, is as yet unknown.

  3. NF-κB p65 repression by the sesquiterpene lactone, Helenalin, contributes to the induction of autophagy cell death

    Directory of Open Access Journals (Sweden)

    Lim Chuan

    2012-07-01

    Full Text Available Abstract Background Numerous studies have demonstrated that autophagy plays a vital role in maintaining cellular homeostasis. Interestingly, several anticancer agents were found to exert their anticancer effects by triggering autophagy. Emerging data suggest that autophagy represents a novel mechanism that can be exploited for therapeutic benefit. Pharmacologically active natural compounds such as those from marine, terrestrial plants and animals represent a promising resource for novel anticancer drugs. There are several prominent examples from the past proving the success of natural products and derivatives exhibiting anticancer activity. Helenalin, a sesquiterpene lactone has been demonstrated to have potent anti-inflammatory and antitumor activity. Albeit previous studies demonstrating helenalin’s multi modal action on cellular proliferative and apoptosis, the mechanisms underlying its action are largely unexplained. Methods To deduce the mechanistic action of helenalin, cancer cells were treated with the drug at various concentrations and time intervals. Using western blot, FACS analysis, overexpression and knockdown studies, cellular signaling pathways were interrogated focusing on apoptosis and autophagy markers. Results We show here that helenalin induces sub-G1 arrest, apoptosis, caspase cleavage and increases the levels of the autophagic markers. Suppression of caspase cleavage by the pan caspase inhibitor, Z-VAD-fmk, suppressed induction of LC3-B and Atg12 and reduced autophagic cell death, indicating caspase activity was essential for autophagic cell death induced by helenalin. Additionally, helenalin suppressed NF-κB p65 expression in a dose and time dependent manner. Exogenous overexpression of p65 was accompanied by reduced levels of cell death whereas siRNA mediated suppression led to augmented levels of caspase cleavage, autophagic cell death markers and increased cell death. Conclusions Taken together, these results show

  4. Experimental Research of Cnidium Lactone Micro - emulsion on the Anti- inflammatory Effect%蛇床子素微乳抗炎作用的实验研究

    Institute of Scientific and Technical Information of China (English)

    李浩铮; 王永辉; 房树标; 高丽; 柴智; 周然

    2015-01-01

    目的:观察蛇床子素微乳的抗炎作用。方法采用二甲苯致小鼠耳肿胀、蛋清致大鼠足跖肿胀的实验动物模型,以浓度为2 mg/ ml,4 mg/ ml,8 mg/ ml 的蛇床子素微乳局部给药,观察蛇床子素微乳局部外用的抗炎作用。结果蛇床子素微乳各剂量组均有不同程度的抑制二甲苯所致小鼠耳廓肿胀的作用,其中,高剂量组与模型对照组、基质对照组相比较差异有统计学意义(P ﹤0.05);蛇床子素微乳各剂量组均有不同程度的抑制蛋清所致大鼠足廓肿胀的作用,其中,高剂量组与模型对照组、基质对照组相比较,在不同测量时间点均有统计学意义(P ﹤0.05),且与皮炎平组相比较差异无统计学意义(P >0.05)。结论蛇床子素微乳局部外用可显著抑制二甲苯所致小鼠耳廓肿胀和蛋清所致的大鼠足跖肿胀,具有明显的抗炎作用。%Objective To observe the anti - inflammatory effect of cnidium lactone micro - emul-sion. Methods Xylene was used to induce auricular swelling in mice and egg white was to induce vola pedis swelling in rats so as to prepare experimental animal models. Cnidium lactone micro - emulsion,2 mg/ ml,4 mg/ ml and 8 mg/ ml was used externally and locally. The anti - inflammatory effect of cnidium lactone micro- emulsion for the local external application was observed. Results Cnidium lactone micro - emulsion of each dose inhibited auricular swelling in mice induced by xylene to different extents,in which,the differences were significant in comparison of the high dose group with the model control group and matrix control group (P ﹤ 0. 05). Cnidium lactone micro - emulsion of each dose inhibited vola pedis swelling induced by egg white in rats to different extents,in which,the differences were significant in comparison of the high dose group with the model control group and matrix control group at different time points(P ﹤ 0. 05),and were not

  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. Sesquiterpene lactone containing extracts from two cultivars of forage chicory (Cichorium intybus) show distinctive chemical profiles and in vitro activity against Ostertagia ostertagi

    DEFF Research Database (Denmark)

    Pena-Espinoza, Miguel Angel; Boas, Ulrik; Williams, Andrew;

    2015-01-01

    The study investigated direct anthelmintic effects of sesquiterpene lactones (SL)-containing extracts from forage chicory against free-living and parasitic stages of Ostertagia ostertagi. Freeze-dried leaves from chicory cultivars ‘Spadona’ and ‘Puna II’ were extracted using methanol/water. Total...... SL were further fractionated by solid-phase extraction and resulting extracts were characterised by high-performance liquid chromatography (HPLC). O. ostertagi eggs from faeces of mono-infected calves were hatched and L1 were used in a larval feeding inhibition assay (LFIA), while cultured L3 were...

  7. Synthesis of δ-lactonic pheromones ofXylocopa hirsutissima andVespa orientalis and an allomone of some ants of genusCamponotus.

    Science.gov (United States)

    Bacardit, R; Moreno-Mañas, M

    1983-06-01

    Simple preparations ofcis-3,6-dimethyltetrahydro-2-pyrone, VII,6-n-undecyltetrahydro-2-pyrone, XVIIb, and 6-n-pentyl-5,6-dihydro-2-pyrone, XVIa, have been achieved. Products VII and XVIIb, respectively, are the major constituent of the pheromonal blend of a carpenter bee (Xylocopa hirsutissima) and the pheromone of the queens of the Oriental hornet (Vespa orientalis). The lactone XVIa is a suspected defensive allomone in two species of formicine ants of the genusCamponotus. All three compounds have been prepared from dehydroacetic acid, I, a cheap and industrially available starting material.

  8. Toward Total Synthesis of Yohimbine and Reserpine Alkaloids; Part 1.An Improved Synthesis of cis-5, 8-Dihydroxy-1, 4, 5, 8, 9,10-hexahydronaphthalene-1, 8-lactone via Selective Reduction of the Conjugated Ketone with Zn (BH4)2

    Institute of Scientific and Technical Information of China (English)

    Yong Ye LI; Mei XU; Fen Er CHEN

    2004-01-01

    An improved and high-yielding synthesis of cis-5, 8-dihydroxy-1, 4, 5, 8, 9, 10- hexa-hydronaphthalene-1,8-lactone 7, an intermediate for (-)-reserpine 1 is presented. The conjugated ketone 5 was regioselectively reduced to afford lactone 7 with zinc borohydride formed in situ from KBH4 and ZnCl2 in THF.

  9. 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.

  10. 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.)

  11. Potent anti-inflammatory activity of sesquiterpene lactones from Neurolaena lobata (L.) R. Br. ex Cass., a Q'eqchi' Maya traditional medicine.

    Science.gov (United States)

    Walshe-Roussel, Brendan; Choueiri, Christine; Saleem, Ammar; Asim, Muhammd; Caal, Federico; Cal, Victor; Rojas, Marco Otarola; Pesek, Todd; Durst, Tony; Arnason, John Thor

    2013-08-01

    The widespread use of Neurolaena lobata (L.) R. Br. ex Cass. by Q'eqchi' Maya and indigenous healers throughout the Caribbean for inflammatory conditions prompted the study of the anti-inflammatory activity of this traditional medicine. The objectives of this study were to conduct a detailed ethnobotanical investigation of the uses of N. lobata by the Q'eqchi' Maya of Belize for a variety of inflammatory symptoms and to evaluate the in vitro anti-inflammatory activity of leaf extract and isolated sesquiterpene lactones. The crude 80% EtOH extract of N. lobata leaves administered at 100 μg/mL reduced LPS-stimulated TNF-α production in THP-1 monocytes by 72% relative to the stimulated vehicle control. Isolated sesquiterpene lactones, neurolenins B, C+D, lobatin B and 9α-hydroxy-8β-isovalerianyloxy-calyculatolide were more active (IC50=0.17-2.32 μM) than the positive control parthenolide (IC50=4.79 μM). The results provide a pharmacological and phytochemical basis for the traditional use of this leaf for inflammatory conditions.

  12. 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.

  13. 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.

  14. Confirmatory method for the determination of resorcylic acid lactones in urine sample using immunoaffinity cleanup and liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, Guglielmo [Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna, ' B. Ubertini' , Via Bianchi 7, 25124 Brescia (Italy)], E-mail: guglielmo.dusi@bs.izs.it; Bozzoni, Eros; Assini, Walter; Tognoli, Nadia; Gasparini, Mara; Ferretti, Enrica [Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna, ' B. Ubertini' , Via Bianchi 7, 25124 Brescia (Italy)

    2009-04-01

    The presence of zeranol ({alpha}-zearalanol) in urine samples due to natural contamination or illegal treatment is under debate within the European Union. The simultaneous determination of zeranol, its epimer taleranol ({beta}-zearalanol), zearalanone and the structurally related mycotoxin zearalenone with the corresponding {alpha}- and {beta}-zearalenol metabolites appears to be critical in deciding whether an illegal use has occurred. The aim of this study is to develop and validate a simple analytical procedure applicable to bovine and swine urine samples for the determination of all six resorcylic acid lactones. After an enzymatic deconjugation, the urine was subjected to a one-step cleanup on a commercially available immunoaffinity chromatography cartridge. The analytes were detected by liquid chromatography-negative-ion electrospray tandem mass spectrometry using deuterium-labelled internal standards. The method was validated as a quantitative confirmatory method according to European Commission Decision 2002/657/EC. The evaluated parameters were: linearity, specificity, precision (repeatability and intra-laboratory reproducibility), recovery, decision limit, detection capability and ruggedness. The decision limits (CC{alpha}) obtained, were between 0.56 and 0.68 {mu}g L{sup -1}; recovery above 66% for all the analytes. Repeatability was between 1.4 and 5.3% and within-laboratory reproducibility between 1.9 and 16.1% for the six resorcylic acid lactones.

  15. Comparative Characterization of Total Flavonol Glycosides and Terpene Lactones at Different Ages, from Different Cultivation Sources and Genders of Ginkgo biloba Leaves

    Directory of Open Access Journals (Sweden)

    Yong Qin

    2012-08-01

    Full Text Available The extract from Ginkgo biloba leaves has become a very popular plant medicine and herbal supplement for its potential benefit in alleviating symptoms associated with peripheral vascular disease, dementia, asthma and tinnitus. Most research on G. biloba leaves focus on the leaves collected in July and August from four to seven year-old trees, however a large number of leaves from fruit cultivars (trees older than 10 years are ignored and become obsolete after fruit harvest season (November. In this paper, we expand the tree age range (from one to 300 years and first comparatively analyze the total flavonol glycosides and terpene lactones at different ages, from different cultivation sources and genders of G. biloba leaves collected in November by using the validated HPLC-ELSD and HPLC-PDA methods. The results show that the contents of total terpene lactones and flavonol glycosides in the leaves of young ginkgo trees are higher than those in old trees, and they are higher in male trees than in female trees. Geographical factors appear to have a significant influence on the contents as well. These results will provide a good basis for the comprehensive utilization of G. biloba leaves, especially the leaves from fruit cultivars.

  16. 川芎中内酯类化合物的质谱学规律%The Regular Patterns of Mass Spectrometry of Lactones from Ligusticum chuanxiong Hort.

    Institute of Scientific and Technical Information of China (English)

    曾志; 谢润乾; 张涛; 谭丽贤; 庾秀英

    2011-01-01

    质谱学在中药药效物质的结构确定中起至关重要的作用,对每一个化合物质谱的确切解释需要对每一个质谱的关键裂解过程具有足够的了解.本研究报道了川芎中具有不饱和侧链与饱和侧链内酯类化合物的质谱学规律.质谱特征峰[M+ -29]和[M+-42]表明了从这些内酯类化合物的分子离子分别失去不饱和侧链上的末端烷基-C2H5和-C3H6基团,这是川芎中具有不饱和侧链内酯类化合物(如(Z)-藁本内酯、(E)-藁本内酯、丁烯基酞内酯和川芎内酯Ⅰ)的典型质谱特征;质谱特征峰[M+-57]显示了从这些内酯类化合物的分子离子失去饱和侧链-C4H9基团,这是川芎中具有饱和侧链内酯类化合物(如丁基酞内酯和川芎内酯A)的典型质谱特征.%Mass spectrometry plays a crucial role in the structure elucidation of those effec-tive substances from traditional Chinese medicine. Secure interpretation of the mass spec-trum of each compound requires an adequate understanding of the key fragmentation process of the mass spectrum. In this paper, the regular patterns of mass spectrometry of lactones with unsaturated side chain and with saturated side chain from Ligusticum chuanxiong Hort. Were reported. The diagnostic peaks at [M+ -29] and [M+ -42] show the molecu-lar ion of the lactones losses a -C2H5 group and a -C3H6 group, respectively, the terminal alkyl groups from the unsaturated side chain. They are typical characteristic of the mass spectra of the lactones with unsaturated side chain from Ligusticum chuanxiong Hort. , such as (Z)-ligustilide. (E)-ligustilide, butylidene phthalide and senkyunolide I. The char-acteristic peak at [M+ -57] displays the molecular ion of the lactones losses a -C4 H9 group from the saturated side chain. This is typical characteristic of the mass spectra of the lactones with saturated side chain from Ligusticum chuanxiong Hort. , such as bu-tylphthalide and senkyunolide A.

  17. Auto-induced expression of Streptomyces griseochromogenes trehalose synthase gene in E.coli and optimization of its two-stage temperature controlling fermentation%灰产色链霉菌海藻糖合成酶的自诱导表达及两阶段温度控制发酵的优化

    Institute of Scientific and Technical Information of China (English)

    杨鑫; 吴茜; 崔怀言; 徐娴; 朱丽英; 江凌

    2015-01-01

    克隆灰产色链霉菌海藻糖合成酶基因(tres),导入大肠杆菌BL21(DE3)中高效表达,并对重组菌自诱导发酵条件进行优化.采用简并PCR的方法扩增灰产色链霉菌海藻糖合成酶基因(tres),将tres基因和表达载体pET28a连接,构建重组质粒pET28a-tres,将其转化到大肠杆菌BL21(DE3)中,筛选重组子进行自诱导表达.利用HPLC法测定酶活研究温度对自诱导发酵海藻糖合成酶催化酶活的影响.该研究成功构建了重组大肠杆菌BL21(DE3).重组菌自诱导表达最优发酵条件:采用两阶段温度控制,37℃培养2.5h,25℃继续培养14 h,并添加3%乙醇,酶活达到1.29× 104U/mL,与传统IPTG恒温培养方式相比酶活提高了55.25%,海藻糖得率达71%.%A novel trehalose synthase gene was cloned from Streptomyces griseochromogenes YX-1 and overexpressed in Escherichia coli BL21 (DE3),and the auto-induced fermentative condition of recombinant bacteria was further optimized.Trehalose synthase gene was successfully amplified from S.griseochromogenes by degenerate PCR.The amplified fragment was linked to pET28a to construct pET28a-tres which were then transformed into E.coli BL21 (DE3).The recon was screened and gene was expressed by auto-induced fermentation.HPLC method was used to investigate the effect of auto-induced fermentative temperature on the trehalose synthase catalytic activity.The recombinant strains of bacteria E.coli BL21 (DE3) were successfully constructed.The optimum fermentation conditions were as follows:cultivating at 37 ℃ for 2.5 h firstly,then culturing in 25 ℃ for 14 h,and adding 3% ethanol simultaneously.The activity of the recombinant enzyme was 1.29 × 104 U/mL,which was 55.25% higher than that of strains traditionally induced with IPTG.The recombinant Tres could catalyze maltose-trehalose interconversion.The production of trehalose reached 71%.The recombinant trehalose synthesized from auto-inducted and two-stage fermentative

  18. Preselection of A- and B- modified d-homo lactone and d-seco androstane derivatives as potent compounds with antiproliferative activity against breast and prostate cancer cells - QSAR approach and molecular docking analysis.

    Science.gov (United States)

    Kovačević, Strahinja Z; Podunavac-Kuzmanović, Sanja O; Jevrić, Lidija R; Vukić, Vladimir R; Savić, Marina P; Djurendić, Evgenija A

    2016-10-10

    The problem with trial-and-error approach in organic synthesis of targeted anticancer compounds can be successfully avoided by computational modeling of molecules, docking studies and chemometric tools. It has been proven that A- and B- modified d-homo lactone and d-seco androstane derivatives are compounds with significant antiproliferative activity against estrogen-independent breast adenocarcinoma (ER-, MDA-MB-231) and androgen-independent prostate cancer cells (AR-, PC-3). This paper presents the quantitative structure-activity relationship (QSAR) models based on artificial neural networks (ANNs) which are able to predict whether d-homo lactone and/or d-seco androstane-based compounds will express antiproliferative activity against breast cancer cells (MDA-MB-231) or not. Also, the present paper describes the molecular docking study of 3β-acetoxy-5α,6α-epoxy- (3) and 6α,7α-epoxy-1,4-dien-3-one (24) d-homo lactone androstane derivatives, as well as 4-en-3-one (15) d-seco androstane derivative, which are compounds with strong or moderate antiproliferative activity against prostate cancer cells (PC-3), and compares them with commercially available medicament for prostate cancer - abiraterone. The obtained promising results can be used as guidelines in further syntheses of novel d-homo lactone and d-seco androstane derivatives with antiproliferative activity against breast and prostate cancer cells.

  19. Synthesis of gamma- and delta-lactones from 1alpha-hydroxy-5,6-trans-vitamin D3 by ring-closing metathesis route and their reduction with metal hydrides.

    Science.gov (United States)

    Wojtkielewicz, Agnieszka; Morzycki, Jacek W

    2007-06-01

    New synthetic pathway towards 19-functionalized derivatives of 1alpha-hydroxy-5,6-trans-vitamin D3 was described. Ring-closing metathesis (RCM) of 1alpha-hydroxy-5,6-trans-vitamin D3 1-omega-alkenoates was a key-step. Hydride reduction of resulting lactones led to the new vitamin D3 analogues.

  20. Comparison of the Pharmacological Effects of ShuXuening and Ginkgo Diterpene Lactone Meglumine Injection%舒血宁和银杏二萜内酯葡胺注射液药理作用比较研究

    Institute of Scientific and Technical Information of China (English)

    房利勤

    2015-01-01

    目的 比较舒血宁注射液和银杏二萜内酯葡胺注射液药理作用的区别,为临床使用提供参考.方法 选择性状相似的小鼠,给予不同剂量的舒血宁注射液和银杏二萜内酯葡胺注射液.结果 高剂量的舒血宁组和银杏二萜内酯葡胺组小鼠的单核-巨噬细胞碳粒廓清指数(K)和吞噬指数(α)均显著升高,均较对照组小鼠有显著性差异( P<0. 05),但银杏二萜内酯葡胺注射液的免疫效果更明显;高剂量的舒血宁和银杏二萜内酯葡胺注射液均显著降低小鼠的收缩压和舒张压,均较对照组具有显著性差异( P<0. 05),但银杏二萜内酯葡胺注射液的降压效果更明显;高剂量的舒血宁注射液和银杏二萜内酯葡胺注射液均能显著促进小鼠的睡眠,入睡比例和入睡时间均较对照组小鼠有显著性差异( P<0. 05),但银杏二萜内酯葡胺注射液组镇静效果更显著.结论 舒血宁注射液和银杏二萜内酯葡胺注射液均有较好的免疫、降血压、中枢镇静作用,但后者的药理活性更强.%Objective To compare the different pharmacological effects of Shuxuening injection and Ginkgo diterpene lactone meglumine Injection to provide suitable clinical reference. Methods Mice with similar traits were chosen and treated with different doses of Shux-uening injection and Ginkgo Diterpene Lactone Meglumine Injection. Results The high dose of Shuxuening Injection group and Ginkgo Diterpene Lactone Meglumine Injection group were significantly increased in mice monocyte-macrophage carbon particle clearance index K and index alpha of phagocytosis, and were lower than those in the control group with significant difference ( P < 0. 05 ) , but the im-mune effects of Ginkgo Diterpene Lactone Meglumine Injection group was more obvious; high dose of Shuxuening Injection group and Ginkgo Diterpene Lactone Meglumine Injection group were significantly decreased in mice systolic and diastolic blood pressure

  1. 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

  2. Growth inhibitory, bactericidal, and morphostructural effects of dehydrocostus lactone from Magnolia sieboldii Leaves on antibiotic-susceptible and -resistant strains of Helicobacter pylori.

    Science.gov (United States)

    Lee, Hyun-Kyung; Song, Ha Eun; Lee, Haeng-Byung; Kim, Cheol-Soo; Koketsu, Mamoru; Ngan, Luong Thi My; Ahn, Young-Joon

    2014-01-01

    Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL) from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide), (-)-epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L) was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L). The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain), clarithromycin (49.8 mg/L for PED 3582GA strain), metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain), or tetracycline (14.2 mg/L for B strain) was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0-7.0). DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h). The Western blot analysis revealed that urease subunits (UreA and UreB) of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (-)-epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori.

  3. Growth inhibitory, bactericidal, and morphostructural effects of dehydrocostus lactone from Magnolia sieboldii Leaves on antibiotic-susceptible and -resistant strains of Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Hyun-Kyung Lee

    Full Text Available Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide, (--epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L. The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain, clarithromycin (49.8 mg/L for PED 3582GA strain, metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain, or tetracycline (14.2 mg/L for B strain was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0-7.0. DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h. The Western blot analysis revealed that urease subunits (UreA and UreB of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (--epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori.

  4. Intramolecular charge transfer with crystal violet lactone in acetonitrile as a function of temperature: reaction is not solvent-controlled.

    Science.gov (United States)

    Druzhinin, Sergey I; Demeter, Attila; Zachariasse, Klaas A

    2013-08-22

    Intramolecular charge transfer (ICT) with crystal violet lactone (CVL) in the excited singlet state takes place in solvents more polar than n-hexane, such as ethyl acetate, tetrahydrofuran, and acetonitrile (MeCN). In these solvents, the fluorescence spectrum of CVL consists of two emission bands, from a locally excited (LE) and an ICT state. The dominant deactivation channel of the lowest excited singlet state is internal conversion, as the quantum yields of fluorescence (0.007) and intersystem crossing (0.015) in MeCN at 25 °C are very small. CVL is a weakly coupled electron donor/acceptor (D/A) molecule, similar to an exciplex (1)(A(-)D(+)). A solvatochromic treatment of the LE and ICT emission maxima results in the dipole moments μe(LE) = 17 D and μe(ICT) = 33 D, much larger than those previously reported. This discrepancy is attributed to different Onsager radii and spectral fluorimeter calibration. The LE and ICT fluorescence decays of CVL in MeCN are double exponential. As determined by global analysis, the LE and ICT decays at 25 °C have the times τ2 = 9.2 ps and τ1 = 1180 ps, with an amplitude ratio of 35.3 for LE. From these parameters, the rate constants ka = 106 × 10(9) s(-1) and kd = 3.0 × 10(9) s(-1) of the forward and backward reaction in the LE ⇄ ICT equilibrium are calculated, resulting in a free enthalpy difference ΔG of -8.9 kJ/mol. The amplitude ratio of the ICT fluorescence decay equals -1.0, which signifies that the ICT state is not prepared by light absorption in the S0 ground state, but originates exclusively from the directly excited LE precursor. From the temperature dependence of the fluorescence decays of CVL in MeCN (-45 to 75 °C), activation energies E(a) = 3.9 kJ/mol (LE → ICT) and E(d) = 23.6 kJ/mol (ICT → LE) are obtained, giving an enthalpy difference ΔH (= E(a) - E(d)) of -19.7 kJ/mol, and an entropy difference ΔS = -35.5 J mol(-1) K(-1). These data show that the ICT reaction of CVL in MeCN is not barrierless

  5. 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.

  6. Preparation of (+)- and (-)- β-phenyl- and β-(4-chlorophenyl)-γ- butyro lactones: Key intermediates in the synthesis of β-phenyl-Gaba and baclofene

    Energy Technology Data Exchange (ETDEWEB)

    Gomez G, J.; Melendez R, M.; Suarez C, O. R.; Castelan D, L. E.; Fragoso V, M. J.; Lopez V, E.; Sanchez Z, M., E-mail: melendez@uaeh.edu.mx [Universidad Autonoma del Estado de Hidalgo, Area Academica de Quimica, Carretera Pachuca-Tulancingo Km. 4.5, Mineral de la Reforma 42184, Hidalgo (Mexico)

    2014-07-01

    the preparation of β-phenyl- and β-(4-chlorophenyl)-γ-butyro lactones (±)-4 and their resolution to the corresponding (+)-(S)-3, (-)-(R)-3 and (+)-(S)-4, (-)-(R)-4 through formation, flash column chromatography separation and subsequent hydrolysis of dia stereoisomeric 4-hydroxybutyramide s (2'R,3S)-5, (2'R,3R)-5, (2'R,3S)-6 and (2'R,3R)-6 is described. The absolute configuration assignment of enantiopure 3 and 4 was supported by X-ray crystallographic structures of (2'R,3R)-5, (2'R,3S)-6 and (2'R,3R)-6. (Author)

  7. Neuroprotective effects of a sesquiterpene lactone and flavanones from Paulownia tomentosa Steud. against glutamate-induced neurotoxicity in primary cultured rat cortical cells.

    Science.gov (United States)

    Kim, Soo-Ki; Cho, Sang-Buem; Moon, Hyung-In

    2010-12-01

    The neuroprotective effects of Paulownia tomentosa against glutamate-induced neurotoxicity were studied in primary cultured rat cortical cells. It was found that the aqueous extract of this medicinal plant significantly attenuated glutamate-induced toxicity. In order to clarify the mechanism(s) underlying this neuroprotective effect, the active fractions and components were isolated and identified. Five compounds were isolated as the methanol extracts from air-dried flowers of P. tomentosa. Isoatriplicolide tiglate exhibited significant neuroprotective activity against glutamate-induced toxicity at concentrations ranging from 1 μM to 10 μM, and exhibited cell viability of approximately 43-78%. Therefore, the neuroprotective effect of P. tomentosa might be due to the inhibition of glutamate-induced toxicity by the sesquiterpene lactone derivative it contains.

  8. cDNA Fragment Cloning of L-Galactono-1,4-Lactone Dehydrogenase and It's Expression in Different Organs of R.roxburghii Tratt

    Institute of Scientific and Technical Information of China (English)

    AN Hua-ming; CHEN Li-geng; FAN Wei-guo

    2004-01-01

    A 855 bp cDNA encoding L-galactono-1,4-lactone dehydrogenase (GalLDH) fragment was cloned from fruit of R. roxburghii Tratt by the method of RT-PCR, on the basis of the homologous genes of Arabidopsis thaliana, cauliflower, sweet potato, strawberry, etc. in GenBank. Sequence analysis showed 79-92% identity in nucleotide sequence and 75-87%identity in amino acid sequence to that of strawberry and Arabidopsis thaliana, etc.Northern blot showed that the expression of GalLDH was significantly different in different organs. The transcription level of GalLDH in fruit was significantly higher than that in leaf, stem and root respectively. Furthermore, this expression mode was highly correlated with AsA levels.

  9. 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.

  10. 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.

  11. 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.

  12. Study on Metamorphic Degree of Lactone Bean Curd by the Conductivity%电导率测定内酯豆腐变质程度的研究

    Institute of Scientific and Technical Information of China (English)

    姚永志; 左锦静

    2013-01-01

    The conductivity and total bacteria of lactone bean curd were determined at 4℃storage conditions in this paper, and it discussed the feasibility for the determination of it's metamorphic degree with conductivity , and explore the correlation between total bacteria and conductivity further. The results showed that it was a high correlation between total bacteria and conductivity, R2 linear=0.994, the linear equation was y=0.007 6x-3.549 9. Therefore, the conductivity can be used as evaluation index to quickly detect the metamorphic degree of lactone bean curd.%通过测定内酯豆腐样品在4℃贮藏条件下随时间不断变化的电导率和样品菌落总数,探讨了用电导率测定内酯豆腐变质程度的可行性,并进一步探讨了电导率数值变化与内酯豆腐菌落总数的相关性。结果表明电导率与内酯豆腐菌落总数之间有高度的相关性,R2线性=0.994,线性方程为y=0.0076x-3.5499。因此,电导率可以作为评价指标来快速检测内酯豆腐的变质程度。

  13. Microbial Baeyer-Villiger oxidation of 5α-steroids using Beauveria bassiana. A stereochemical requirement for the 11α-hydroxylation and the lactonization pathway.

    Science.gov (United States)

    Świzdor, Alina; Panek, Anna; Milecka-Tronina, Natalia

    2014-04-01

    Beauveria bassiana KCH 1065, as was recently demonstrated, is unusual amongst fungal biocatalysts in that it converts C19 3-oxo-4-ene and 3β-hydroxy-5-ene as well as 3β-hydroxy-5α-saturated steroids to 11α-hydroxy ring-D lactones. The Baeyer-Villiger monooxygenase (BVMO) of this strain is distinguished from other enzymes catalyzing BVO of steroidal ketones by the fact that it oxidizes solely substrates with 11α-hydroxyl group. The current study using a series of 5α-saturated steroids (androsterone, 3α-androstanediol and androstanedione) has highlighted that a small change of the steroid structure can result in significant differences of the metabolic fate. It was found that the 3α-stereochemistry of hydroxyl group restricted "normal" binding orientation of the substrate within 11α-hydroxylase and, as a result, androsterone and 3α-androstanediol were converted into a mixture of 7β-, 11α- and 7α-hydroxy derivatives. Hydroxylation of androstanedione occurred only at the 11α-position, indicating that the 3-oxo group limits the alternative binding orientation of the substrate within the hydroxylase. Only androstanedione and 3α-androstanediol were metabolized to hydroxylactones. The study uniquely demonstrated preference for oxidation of equatorial (11α-, 7β-) hydroxyketones by BVMO from B. bassiana. The time course experiments suggested that the activity of 17β-HSD is a factor determining the amount of produced ring-D lactones. The obtained 11α-hydroxylactones underwent further transformations (oxy-red reactions) at C-3. During conversion of androstanedione, a minor dehydrogenation pathway was observed with generation of 11α,17β-dihydroxy-5α-androst-1-en-3-one. The introduction of C1C2 double bond has been recorded in B. bassiana for the first time.

  14. 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.

  15. Oxalone and lactone moieties of podophyllotoxin exhibit properties of both the B and C rings of colchicine in its binding with tubulin.

    Science.gov (United States)

    Gupta, Suvroma; Das, Lalita; Datta, Ajit B; Poddar, Asim; Janik, Mark E; Bhattacharyya, Bhabatarak

    2006-05-23

    Thermodynamics of podophyllotoxin binding to tubulin and its multiple points of attachment with tubulin has been studied in detail using isothermal titration calorimetry. The calorimetric enthalpy of the association of podophyllotoxin with tubulin is negative and occurs with a negative heat capacity change (DeltaC(p) = -2.47 kJ mol(-)(1) K(-)(1)). The binding is unique with a simultaneous participation of both hydrophobic and hydrogen-bonding forces with unfavorable negative entropic contribution at higher temperature, favored with an enthalpy-entropy compensation. Interestingly, the binding of 2-methoxy-5-(2',3',4'-trimethoxyphenyl)tropone (AC, a colchicine analogue without the B ring) with tubulin is enthalpy-favored. However, the podophyllotoxin-tubulin association depending upon the temperature of the reaction has a favorable entropic and enthalpic component, which resembles both B- and C-ring properties of colchicine. On the basis of the crystal structure of the podophyllotoxin-tubulin complex, distance calculations have indicated a possible interaction between threonine 179 of alpha-tubulin and the hydroxy group on the D ring of podophyllotoxin. To confirm the involvement of the oxalone moiety as well as the lactone ring of podophyllotoxin in tubulin binding, analogues of podophyllotoxin are synthesized with methoxy substitution at the 4' position of ring D along with its isomer and another analogue epimerized at ring E. From these results, involvement of oxalone as well as the lactone ring of the drug in a specific orientation inclusive of ring A is indicated for podophyllotoxin-tubulin binding. Therefore, podophyllotoxin, like colchicine, behaves as a bifunctional ligand having properties of both the B and C rings of colchicine by making more than one point of attachment with the protein tubulin.

  16. 豆浆处理工艺改善内酯豆腐的质构特性%Treatment technology of soy milk improving texture characteristics of lactone tofu

    Institute of Scientific and Technical Information of China (English)

    于滨; 王喜波

    2014-01-01

    Tofu is a nutritional, gel-like soy food. Its preparation generally includes soaking and grinding of soybeans in water, filtering, boiling and coagulation of soy milk, molding and pressing in the same basic methods. It is consumed in significant amounts in Asian countries like China and Japan because of their inexpensive, high quality protein. Because of its bland taste, the textural properties markedly influence its food quality and consumer acceptability. The textural properties are governed by soy milk concentration, coagulant type and concentration, gelation pressure and temperature, and gelation time. The textural properties of tofu also varied with the density of the gel network, the size of protein granules in the network from microscopic view. The particle size of soy milk was changed by some treatments to improve the texture characteristics of lactone tofu. Effect of plate gap (10-30μm), ultrasound power (1-3 W/g) and homogenate speed (1 000-5 000 r/min) on texture characteristics of lactone tofu were studied in this article. The results showed that treatment with colloid mill significantly (p<0.05) increased elasticity and cohesion of lactone tofu. However, grinding for longer time lowered hardness of lactone tofu under the condition of plate gap of 10μm. Treatment of soy milk for 2 min under the plate gap of 10μm effectively improved the quality and texture characteristics of lactone tofu. Hardness and elasticity of lactone tofu all offered upgrade firstly then descending latter tendency under different intensities of ultrasound power. Cohesion of lactone tofu was decreased significantly (p<0.05) by ultrasound treatments. Treatment with ultrasound powder of 2 W/g for 3 min exhibited better quality of lactone tofu. All texture characteristics of lactone tofu showed descending following its ascending under homogenate conditions. Soy milk treated by homogenate at 1 000 r/min for 8 min was better choice. By multi-index comprehensive evaluation of Topsis

  17. Contraceptive progestins. Various 11-substituents combined with four 17-substituents: 17alpha-ethynyl, five- and six-membered spiromethylene ethers or six-membered spiromethylene lactones.

    Science.gov (United States)

    Schoonen, W G; Deckers, G; de Gooijer, M E; de Ries, R; Mathijssen-Mommers, G; Hamersma, H; Kloosterboer, H J

    2000-10-01

    Norethisterone (NET) is a 19-nortestosterone derivative with progestagenic and some androgenic activity, which was used in the first generation of contraceptives. NET was succeeded by levonorgestrel (LNG) and later on by desogestrel (DSG) and gestodene (GSD). Although these latter two progestins had increased potency, there was still androgenicity with gestodene and to a lesser extent with desogestrel. New progestins were synthesized in order to further enhance progestagenic and to reduce androgenic activity. Four different chemical moieties were introduced in position 17 of 19-nortestosterone, viz. 17alpha-ethynyl, five- and six-membered spiromethylene ethers, and a six-membered-spiromethylene lactone. In combination with these structures seven different substituents were added at position 11, i.e. methylene, methyl, ethyl, ethenyl, ethynyl, 2-propenyl and 1-propynyl. All substituents except for methylene occupied the 11beta-position. All these 32 compounds were synthesized and analysed in vitro and in vivo against etonogestrel (ETG, 3-keto-desogestrel), the biologically active metabolite of desogestrel. Their relative binding potency to progesterone (PR), androgen (AR) and estrogen (ER) receptors were determined in cell lysates of human breast tumor MCF-7 cells and to glucocorticoid (GR) receptors in that of human leukemic IM-9 cells. Moreover, their relative agonistic activities were assessed in Chinese hamster ovary cell-based transactivation assays. All in vivo activities were determined in McPhail (progestagenic), ovulation inhibition (progestagenic and estrogenic), Hershberger (androgenic), hormone screening (glucocorticoid and estrogen) and Allen-Doisy (estrogenic) tests after oral and for the McPhail test also after subcutaneous administration. The progestagenic binding and transactivation potencies of all compounds in the three 17-spiro series were higher than those of the corresponding analogues in the 17alpha-ethynyl series. None of the compounds showed

  18. Curiouser and Curiouser: The Macrocyclic Lactone, Abamectin, Is also a Potent Inhibitor of Pyrantel/Tribendimidine Nicotinic Acetylcholine Receptors of Gastro-Intestinal Worms.

    Science.gov (United States)

    Abongwa, Melanie; Buxton, Samuel K; Robertson, Alan P; Martin, Richard J

    2016-01-01

    Nematode parasites may be controlled with drugs, but their regular application has given rise to concerns about the development of resistance. Drug combinations may be more effective than single drugs and delay the onset of resistance. A combination of the nicotinic antagonist, derquantel, and the macrocyclic lactone, abamectin, has been found to have synergistic anthelmintic effects against gastro-intestinal nematode parasites. We have observed in previous contraction and electrophysiological experiments that derquantel is a potent selective antagonist of nematode parasite muscle nicotinic receptors; and that abamectin is an inhibitor of the same nicotinic receptors. To explore these inhibitory effects further, we expressed muscle nicotinic receptors of the nodular worm, Oesophagostomum dentatum (Ode-UNC-29:Ode-UNC-63:Ode-UNC-38), in Xenopus oocytes under voltage-clamp and tested effects of abamectin on pyrantel and acetylcholine responses. The receptors were antagonized by 0.03 μM abamectin in a non-competitive manner (reduced Rmax, no change in EC50). This antagonism increased when abamectin was increased to 0.1 μM. However, when we increased the concentration of abamectin further to 0.3 μM, 1 μM or 10 μM, we found that the antagonism decreased and was less than with 0.1 μM abamectin. The bi-phasic effects of abamectin suggest that abamectin acts at two allosteric sites: one high affinity negative allosteric (NAM) site causing antagonism, and another lower affinity positive allosteric (PAM) site causing a reduction in antagonism. We also tested the effects of 0.1 μM derquantel alone and in combination with 0.3 μM abamectin. We found that derquantel on these receptors, like abamectin, acted as a non-competitive antagonist, and that the combination of derquantel and abamectin produced greater inhibition. These observations confirm the antagonistic effects of abamectin on nematode nicotinic receptors in addition to GluCl effects, and illustrate more complex

  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. Curiouser and Curiouser: The Macrocyclic Lactone, Abamectin, Is also a Potent Inhibitor of Pyrantel/Tribendimidine Nicotinic Acetylcholine Receptors of Gastro-Intestinal Worms.

    Directory of Open Access Journals (Sweden)

    Melanie Abongwa

    Full Text Available Nematode parasites may be controlled with drugs, but their regular application has given rise to concerns about the development of resistance. Drug combinations may be more effective than single drugs and delay the onset of resistance. A combination of the nicotinic antagonist, derquantel, and the macrocyclic lactone, abamectin, has been found to have synergistic anthelmintic effects against gastro-intestinal nematode parasites. We have observed in previous contraction and electrophysiological experiments that derquantel is a potent selective antagonist of nematode parasite muscle nicotinic receptors; and that abamectin is an inhibitor of the same nicotinic receptors. To explore these inhibitory effects further, we expressed muscle nicotinic receptors of the nodular worm, Oesophagostomum dentatum (Ode-UNC-29:Ode-UNC-63:Ode-UNC-38, in Xenopus oocytes under voltage-clamp and tested effects of abamectin on pyrantel and acetylcholine responses. The receptors were antagonized by 0.03 μM abamectin in a non-competitive manner (reduced Rmax, no change in EC50. This antagonism increased when abamectin was increased to 0.1 μM. However, when we increased the concentration of abamectin further to 0.3 μM, 1 μM or 10 μM, we found that the antagonism decreased and was less than with 0.1 μM abamectin. The bi-phasic effects of abamectin suggest that abamectin acts at two allosteric sites: one high affinity negative allosteric (NAM site causing antagonism, and another lower affinity positive allosteric (PAM site causing a reduction in antagonism. We also tested the effects of 0.1 μM derquantel alone and in combination with 0.3 μM abamectin. We found that derquantel on these receptors, like abamectin, acted as a non-competitive antagonist, and that the combination of derquantel and abamectin produced greater inhibition. These observations confirm the antagonistic effects of abamectin on nematode nicotinic receptors in addition to GluCl effects, and

  1. The Protective Effect of Dehydrocostus Lactone on Liver Injury in Laboratory Rats%去氢木香内酯对实验性大鼠肝损伤的保护作用

    Institute of Scientific and Technical Information of China (English)

    孙文利; 李德凤; 刘玉欣; 李韶菁; 张晓旭; 黄志英; 陈畅; 康琛; 高健; 段飞鹏; 田朋朋; 陈坤

    2015-01-01

    目的:研究去氢木香内酯对大鼠肝损伤模型的保护作用。方法:以氨基半乳糖、四氯化碳建立大鼠肝损伤模型,分别设正常对照组、模型组、阳性药对照组(0.2 mg/kg)、去氢木香内酯高、中、低剂量组(45 mg/kg,15 mg/kg,5 mg/kg),测定各组大鼠血清中丙氨酸氨基转移酶(Alanine Aminotransferase,ALT)、天门冬酸氨基转移酶(Aspartate Aminotransferase, AST)活性及肝组织中丙二醛(Malondialdehyde,MDA)含量。另以 HE、Masson 染色,对各组大鼠肝脏作病理检查。结果:与模型组相比,去氢木香内酯可显著降低大鼠血清 ALT、AST 的活性及 MDA 的含量(P <0.05),减轻大鼠肝脏坏死性病理改变。结论:去氢木香内酯对大鼠肝脏损伤有较好的保护作用。%Objective:To investigate the protective effect of Dehydrocostus lactone on liver injury in experimental rats.Methods:Rats were injected with galactosamine and carbon tetrachloride to induce liver injury.The model rats were randomly divided into normal group,vehicle control,positive control group (0.2 mg·kg -1 ),high,middle,and low Dehydrocostus lactone dose groups (45,15 and 5 mg·kg).The changes of activity of ALT,AST in serum and MDA content in liver tissue were measured.The pathologic change of liver tissue was examined under light microscope by HE and Masson staining.Results:Compared with the ve-hicle group,Dehydrocostus lactone remarkably decreased (P <0.05)the activities of ALT,AST in serum and MDA content in liver tissue.It was observed that Dehydrocostus lactone could significantly alleviate the necrotic pathologic change of liver tissue. Conclusion:Dehydrocostus lactone has protective effects on liver injury in labortary rats.

  2. Changes in Terpene Lactones of Ginkgo biloba and Its Relation with Chlorophyll Fluorescence Characters%银杏叶萜内酯含量的变化及其与叶绿素荧光特性的关系

    Institute of Scientific and Technical Information of China (English)

    肖强; 张峥; 周大寨

    2015-01-01

    为探究银杏(Ginkgo biloba)叶萜类内酯含量和光合同化作用的关系,对其内酯含量和叶绿素荧光特性进行了研究。结果表明,不同采收时间银杏叶中白果内酯和银杏内酯含量有显著差异,总体上,5月份含量较低,此后逐渐升高,8月份达到高峰,然后快速下降,10月底最低;与此同时,银杏叶片的光合色素以及叶绿素荧光参数也呈现周期性变化。白果内酯以及萜内酯含量与叶绿素荧光参数Y(NPQ)之间呈极显著正相关关系,因此,可以通过银杏叶片的叶绿素荧光参数预测白果内酯和萜内酯含量。%In order to understand the relationship between contents of terpene lactones and photosynthetic characters in Ginkgo biloba leaves, the contents of terpene lactones were determined and chlorophyll lfuorescence features was studied. The results showed that the changes in terpene lactone contents were signiifcant at different harvest time. In general, bilobalide and ginkgolide contents were low in May, then increased gradually, reached peak in August, and afterwards decreased until the end of October. At the same time, the photosynthetic pigment content and chlorophyll lfuorescence parameters in leaves showed periodical changes. The contents of bilobalide and lactone had significant positive correlation with chlorophyll fluorescence index of Y(NPQ). So, it was suggested that bilobalide and lactone contents could be forecasted by chlorophyll lfuorescence parameters.

  3. 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.

  4. 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.

  5. 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.

  6. The specific cleavage of lactone linkage to open-loop in cyclic lipopeptide during negative ESI tandem mass spectrometry: the hydrogen bond interaction effect of 4-ethyl guaiacol.

    Directory of Open Access Journals (Sweden)

    Mengzhe Guo

    Full Text Available Mass spectrometry is a valuable tool for the analysis and identification of chemical compounds, particularly proteins and peptides. Lichenysins G, the major cyclic lipopeptide of lichenysin, and the non-covalent complex of lichenysins G and 4-ethylguaiacol were investigated with negative ion ESI tandem mass spectrometry. The different fragmentation mechanisms for these compounds were investigated. Our study shows the 4-ethylguaiacol hydrogen bond with the carbonyl oxygen of the ester group in the loop of lichenysins G. With the help of this hydrogen bond interaction, the ring structure preferentially opens in lactone linkage rather than O-C bond of the ester-group to produce alcohol and ketene. Isothermal titration 1H-NMR analysis verified the hydrogen bond and determined the proportion of subject and ligand in the non-covalent complex to be 1∶1. Theoretical calculations also suggest that the addition of the ligand can affect the energy of the transition structures (TS during loop opening.

  7. 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.

  8. Chemo-Enzymatic Synthesis of Chiral Epoxides Ethyl and Methyl (S-3-(Oxiran-2-ylpropanoates from Renewable Levoglucosenone: An Access to Enantiopure (S-Dairy Lactone

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    Aurélien A. M. Peru

    2016-07-01

    Full Text Available Chiral epoxides—such as ethyl and methyl (S-3-(oxiran-2-ylpropanoates ((S-1a/1b—are valuable precursors in many chemical syntheses. Until recently, these compounds were synthesized from glutamic acid in four steps (deamination, reduction, tosylation and epoxide formation in low to moderate overall yield (20%–50%. Moreover, this procedure requires some harmful reagents such as sodium nitrite ((ecotoxic and borane (carcinogen. Herein, starting from levoglucosenone (LGO, a biobased chiral compound obtained through the flash pyrolysis of acidified cellulose, we propose a safer and more sustainable chemo-enzymatic synthetic pathway involving lipase-mediated Baeyer-Villiger oxidation, palladium-catalyzed hydrogenation, tosylation and treatment with sodium ethoxide/methoxide as key steps. This route afforded ethyl and methyl (S-3-(oxiran-2-ylpropanoates in 57% overall yield, respectively. To demonstrate the potentiality of this new synthetic pathway from LGO, the synthesis of high value-added (S-dairy lactone was undertaken from these epoxides and provided the target in 37% overall yield from LGO.

  9. Hollow-shell-structured nanospheres: a recoverable heterogeneous catalyst for rhodium-catalyzed tandem reduction/lactonization of ethyl 2-acylarylcarboxylates to chiral phthalides.

    Science.gov (United States)

    Liu, Rui; Jin, Ronghua; An, Juzeng; Zhao, Qiankun; Cheng, Tanyu; Liu, Guohua

    2014-05-01

    Chiral organorhodium-functionalized hollow-shell-structured nanospheres were prepared by immobilization of a chiral N-sulfonylated diamine-based organorhodium complex within an ethylene-bridged organosilicate shell. Structural analysis and characterization reveal its well-defined single-site rhodium active center, and transmission electron microscopy images reveal a uniform dispersion of hollow-shell-structured nanospheres. As a heterogenous catalyst, it exhibits excellent catalytic activity and enantioselectivity in synthesis of chiral phthalides by a tandem reduction/lactonization of ethyl 2-acylarylcarboxylates in aqueous medium. The high catalytic performance is attributed to the synergistic effect of the high hydrophobicity and the confined chiral organorhodium catalytic nature. The organorhodium-functionalized nanospheres could be conveniently recovered and reused at least 10 times without loss of catalytic activity. This feature makes it an attractive catalyst in environmentally friendly organic reactions. The results of this study offer a new approach to immobilize chiral organometal functionalities within the hollow-shell-structured nanospheres to prepare materials with high activity in heterogeneous asymmetric catalysis.

  10. Quantification of phenolic acids and their methylates, glucuronides, sulfates and lactones metabolites in human plasma by LC-MS/MS after oral ingestion of soluble coffee.

    Science.gov (United States)

    Marmet, Cynthia; Actis-Goretta, Lucas; Renouf, Mathieu; Giuffrida, Francesca

    2014-01-01

    Chlorogenic acids and derivatives like phenolic acids are potentially bioactive phenolics, which are commonly found in many foods. Once absorbed, chlorogenic and phenolic acids are highly metabolized by the intestine and the liver, producing glucuronidated and/or sulphated compounds. These metabolites were analyzed in human plasma using a validated liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method. After protein precipitation, phenolic acids and their metabolites were extracted by using ethanol and chromatographic separation was achieved by reversed-phase using an Acquity UPLC BEH C18 column combined with a gradient elution system using 1% acetic acid aqueous solution and 1% acetic acid with 100% acetonitrile. The method was able to quantify 56 different compounds including 24 phenolic acids, 4 lactones, 15 sulfates and 13 glucuronides metabolites between 5 and 1000nM in plasma for most of them, except for m-dihydrocoumaric acid, 5-ferulloylquinic-glucuronide, 4-methoxycinnamic acid, 3-phenylpropionic acid, 3-(4-methoxyphenyl)propionic acid (25 to 1000nM) and p-dihydrocoumaric acid (50-1000nM). Values of repeatability and intermediate reproducibility were below 15% of deviation in general, and maximum 20% for the lowest concentrations. The validated method was successfully applied to quantify phenolic acids and their metabolites in plasma obtained after oral ingestion of soluble coffee. In conclusion, the developed and validated method is proved to be very sensitive, accurate and precise for the quantification of these possible dietary phenols.

  11. Responses of the Microalga Chlorophyta sp. to Bacterial Quorum Sensing Molecules (N-Acylhomoserine Lactones): Aromatic Protein-Induced Self-Aggregation.

    Science.gov (United States)

    Zhou, Dandan; Zhang, Chaofan; Fu, Liang; Xu, Liang; Cui, Xiaochun; Li, Qingcheng; Crittenden, John C

    2017-03-21

    Bacteria and microalgae often coexist during the recycling of microalgal bioresources in wastewater treatment processes. Although the bacteria may compete with the microalgae for nutrients, they could also facilitate microalgal harvesting by forming algal-bacterial aggregates. However, very little is known about interspecies interactions between bacteria and microalgae. In this study, we investigated the responses of a model microalga, Chlorophyta sp., to the typical quorum sensing (QS) molecules N-acylhomoserine lactones (AHLs) extracted from activated sludge bacteria. Chlorophyta sp. self-aggregated in 200 μm bioflocs by secreting 460-1000 kDa aromatic proteins upon interacting with AHLs, and the settling efficiency of Chlorophyta sp. reached as high as 41%. However, Chlorophyta sp. cells were essentially in a free suspension in the absence of AHLs. Fluorescence intensity of the aromatic proteins had significant (P microalga. Transcriptome results further revealed up-regulation of synthesis pathways for aromatic proteins from tyrosine and phenylalanine that was assisted by anthranilate accumulation. To the best of our knowledge, this is the first study to confirm that eukaryotic microorganisms can sense and respond to prokaryotic QS molecules.

  12. Antiproliferative effect from sesquiterpene lactone s of Carpesium rosulatum MlQ consumed in South Korea on the five human cancer cell lines

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    Hyung-In Moon

    2010-07-01

    Full Text Available In search for antiproliferative compound against human cancer cells (A549, SK-OV-3, SK-MEL-2, XF498, HCT15, a chloroform soluble extract obtained by re-extraction of the methanol extract of whole plant of Carpesium rosulatum MlQ. (Compositae exhibited cytotoxic activity. Four germacrane sesquiterpene lactones 2α,5-epoxy-5,10-dihydroxy-6-angeloyl-oxy-9β-isobutyloxy-germacran-8α,12-olide, 2α,5-epoxy-5,10-dihydroxy-6α,9β-diangeloyloxy-germacran-8α,12-olide, 2α,5-epoxy-5,10-dihydroxy-6α-angeloyloxy-9β-(3-methyl-butanoyloxy-germacran-8α,12-olide, and 2β,5-epoxy-5,10-dihydroxy-6α,9β-diangeloyloxy-germacran-8α,12-olide were isolated from the chloroform extract of C . rosulatum, and 2α,5-epoxy-5,10-dihydroxy-6α,9β-diangeloyloxy-germacran-8α,12-olide showed the most potent cytotoxicity with IC 50 value of 6.01 μM against SK-MEL-2 .

  13. 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.

  14. 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.

  15. 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.

  16. Sesquiterpene lactones in Arnica montana: a rapid analytical method and the effects of flower maturity and simulated mechanical harvesting on quality and yield.

    Science.gov (United States)

    Douglas, James A; Smallfield, Bruce M; Burgess, Elaine J; Perry, Nigel B; Anderson, Rosemary E; Douglas, Malcolm H; Glennie, V LeAnne

    2004-02-01

    A rapid extraction, clean-up and RPLC procedure suitable for routine quantitative analyses of sesquiterpene lactones (SLs) in Arnica montana is described. Seven SLs were isolated of which tigloyl and methacryloyl esters of helenalin made up over 50 % of the total. This method was applied to analyses of replicated samples of different flower parts, different stages of flower maturity, and herb from different harvest methods. The mean total SL levels were higher in the disk flowers (0.872 % w/w) than the ray flowers (0.712 %), lower in the flower receptacles (0.354 %) and lowest in stems (0.028 %). Relative levels of individual SLs varied significantly between flower parts, especially acetyldihydrohelenalin which had its highest concentration in stems. The total SL contents increased progressively as the flowers matured, from 0.512 % in buds to 0.943 % in withered flowers. Harvesting a range of flower maturities at one time in a simulated mechanical harvest, followed by mechanical separation of low quality stem material gave the same quality as hand harvested A. montana flowers (over 0.8 % total SLs) and the flower yields from the two processes were similar when adjusted for harvesting technique (320 kg dry matter/ha by hand, 295 kg/ha mechanical). Delaying flower harvest until the flower petals had withered greatly improved the SL concentration of the drug.

  17. A sesquiterpene lactone from a medicinal herb inhibits proinflammatory activity of TNF-α by inhibiting ubiquitin-conjugating enzyme UbcH5.

    Science.gov (United States)

    Liu, Li; Hua, Yaping; Wang, Dan; Shan, Lei; Zhang, Yuan; Zhu, Junsheng; Jin, Huizi; Li, Honglin; Hu, Zhenlin; Zhang, Weidong

    2014-10-23

    UbcH5 is the key ubiquitin-conjugating enzyme catalyzing ubiquitination during TNF-α-triggered NF-κB activation. Here, we identified an herb-derived sesquiterpene lactone compound IJ-5 as a preferential inhibitor of UbcH5 and explored its therapeutic value in inflammatory and autoimmune disease models. IJ-5 suppresses TNF-α-induced NF-κB activation and inflammatory gene transcription by inhibiting the ubiquitination of receptor-interacting protein 1 and NF-κB essential modifier, which is essential to IκB kinase activation. Mechanistic investigations revealed that IJ-5 preferentially binds to and inactivates UbcH5 by forming a covalent adduct with its active site cysteine and thereby preventing ubiquitin conjugation to UbcH5. In preclinical models, pretreatment of IJ-5 exhibited potent anti-inflammatory activity against TNF-α- and D-galactosamine-induced hepatitis and collagen-induced arthritis. These findings highlight the potential of UbcH5 as a therapeutic target for anti-TNF-α interventions and provide an interesting lead compound for the development of new anti-inflammation agents.

  18. Development and validation of a method for the determination of low-ppb levels of macrocyclic lactones in butter, using HPLC-fluorescence.

    Science.gov (United States)

    Macedo, Fabio; Marsico, Eliane Teixeira; Conte-Júnior, Carlos Adam; de Resende, Michele Fabri; Brasil, Taila Figueiredo; Pereira Netto, Annibal Duarte

    2015-07-15

    An analytical method was developed and validated for the simultaneous determination of four macrocyclic lactones (ML) (abamectin, doramectin, ivermectin and moxidectin) in butter, using liquid chromatography with fluorescence detection. The method employed heated liquid-liquid extraction and a mixture of acetonitrile, ethyl acetate and water, with preconcentration and derivatization, to produce stable fluorescent derivatives. The chromatographic run time was validation followed international guidelines and employed fortified butter samples. The figures of merit obtained, e.g. recovery (72.4-106.5%), repeatability (8.8%), within-laboratory reproducibility (15.7%) and limits of quantification (0.09-0.16 μg kg(-1)) were satisfactory for the desired application. The application of the method to real samples showed that ML residues were present in six of the ten samples evaluated. The method proved to be simple, easy and appropriate for simultaneous determination of ML residues in butter. To our knowledge, this is the first method described for the evaluation of ML in butter.

  19. Differential effects of Helenalin, an anti-inflammatory sesquiterpene lactone, on the proteome, metabolome and the oxidative stress response in several immune cell types.

    Science.gov (United States)

    Zwicker, Paula; Schultze, Nadin; Niehs, Sarah; Albrecht, Dirk; Methling, Karen; Wurster, Martina; Wachlin, Gerhild; Lalk, Michael; Lindequist, Ulrike; Haertel, Beate

    2016-12-18

    Extracts of Arnica spp. are traditionally used due to their anti-inflammatory effects for the topical treatment of e.g. haematoma or muscle distortions. One of the main active compounds is Helenalin, a sesquiterpene lactone that can be found in various Asteraceae. However, immunotoxic effects of the compound are only poorly analysed. In this study, a 2D gel electrophoresis based proteomic approach together with a membrane based proteomic assay, metabolomics and the detection of intracellular reactive oxygen species (iROS) were used to investigate potential immunotoxic properties of Helenalin on the human immune cell lines Jurkat and THP-1 and on human peripheral blood mononuclear cells (PBMC). The study revealed a dose-dependent cytotoxicity towards both tested cell lines and the PBMC. However, the cell lines were less sensitive to the Helenalin treatment than the PBMC. The proteomic assays showed strong effects on the carbohydrate metabolism and the protein folding in THP-1 cells but only weak impact on Jurkat cells. Metabolomic studies as well as iROS detection in THP-1 cells verified the results of the proteomic analysis. In summary, the approaches used in this study were able to identify target pathways of Helenalin especially in THP-1 monocytes and thus enable a risk assessment of the substance.

  20. Effects of drought stress on annual dynamic changing pattern of the terpene lactones content in Ginkgo biloba leaves%干旱胁迫对银杏叶萜内酯年动态变化的影响

    Institute of Scientific and Technical Information of China (English)

    朱灿灿; 曹福亮; 王贵斌; 耿国民

    2011-01-01

    The effects of drought stress on terpene lactones contents of Ginkgo biloba grown in pots at 4 soil moisture levels under greenhouse conditions were investigated. The results showed that there were significant effects on the contents of bi-lobalide BB, ginkgolide GC, CA, CB and total terpene lactones in different growing seasons. With the development of season, terpene lactones contents were increased first and then decline at the subsequent. Moderate drought conditions can contribute to the synthesis of terpene lactones. The terpene lactones contents in mild and moderate drought conditions significantly increased if compared with the terpene lactones contents in appropriate water condition. Concerning the leaf yield, terpene lactones contents as well as the relationship between quantity and time of leaf collection, we suggested that the highest economic yield per single plant could be obtained by controlling soil water content at mild level ( relative water content ,55% -60% ) and harvesting leaves in June to October.%以2年生盆栽实生苗为研究材料,通过人工模拟干旱胁迫环境,探索4水平干旱胁迫(土壤含水量分别为田间持水量的75% ~ 80%、55% ~ 60%、40% ~45%和30%~35%)对银杏叶萜内酯类物质季节变化的影响.结果表明:干旱胁迫下,生长季节不同,银杏叶内白果内酯BB、银杏内酯GC、GA、GB及总萜内酯含量变化具有显著差异,随着生长季节的变化银杏叶萜内酯类物质含量变化呈“先升高后降低”的趋势.适度干旱条件下可以促进银杏萜内酯类物质的合成,尤其轻度和中度干旱条件下,萜内酯含量比适宜水分条件下明显增多.考虑到叶产量、叶萜内酯美物质含量以及采叶与采时的关系等,在实际生产中可以考虑在植物生长初期,给予银杏苗正常的水分供应以获得最大的生物产量,在6-10月份叶片发育完全后适当进行轻度干旱处理(土壤水分含量

  1. 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.

  2. Thiol dependent NF-κB suppression and inhibition of T-cell mediated adaptive immune responses by a naturally occurring steroidal lactone Withaferin A.

    Science.gov (United States)

    Gambhir, Lokesh; Checker, Rahul; Sharma, Deepak; Thoh, M; Patil, Anand; Degani, M; Gota, Vikram; Sandur, Santosh K

    2015-12-01

    Withaferin A (WA), a steroidal lactone isolated from ayurvedic medicinal plant Withania somnifera, was shown to inhibit tumor growth by inducing oxidative stress and suppressing NF-κB pathway. However, its effect on T-cell mediated adaptive immune responses and the underlying mechanism has not been investigated. Since both T-cell responses and NF-κB pathway are known to be redox sensitive, the present study was undertaken to elucidate the effect of WA on adaptive immune responses in vitro and in vivo. WA inhibited mitogen induced T-cell and B-cell proliferation in vitro without inducing any cell death. It inhibited upregulation of T-cell (CD25, CD69, CD71 and CD54) and B-cell (CD80, CD86 and MHC-II) activation markers and secretion of Th1 and Th2 cytokines. WA induced oxidative stress by increasing the basal ROS levels and the immunosuppressive effects of WA were abrogated only by thiol anti-oxidants. The redox modulatory effects of WA in T-cells were attributed to its ability to directly interact with free thiols. WA inhibited NF-κB nuclear translocation in lymphocytes and prevented the direct binding of nuclear NF-κB to its consensus sequence. MALDI-TOF analysis using a synthetic NF-κB-p50 peptide containing Cys-62 residue suggested that WA can modify the cysteine residue of NF-κB. The pharmacokinetic studies for WA were also carried out and in vivo efficacy of WA was studied using mouse model of Graft-versus-host disease. In conclusion, WA is a potent inhibitor of T-cell responses and acts via a novel thiol dependent mechanism and inhibition of NF-κB pathway.

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

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    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.

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

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    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.

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

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    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.

  6. Synthesis of Lactonic Crown Ethers by Ethoxylation of γ-Butyrolactone%γ-丁内酯乙氧基化合成内酯冠醚

    Institute of Scientific and Technical Information of China (English)

    胡学一; 方云; 赵权

    2012-01-01

    Lactonic crown ethers were synthesized by a novel insertion reaction oi ethylene oxides into γ-butyrolac:tone(GBL) catalyzed by Al-Mg composite oxide, and the molecular structures of the target products were confirmed by FTIR and ES1-MS. The process was optimized with respect to Al/Mg molar ratio of catalysts, reaction temperature and pressure. The conversion of GBL was 75.2% when the insertion reaction was catalyzed by 1% of LE -4 catalyst based on the target products and run in 5 times molar ratio of EO to GBL at 160℃ under 0.65 MPa.%以Al-Mg基复合氧化物为催化剂,尝试采用环氧乙烷(EO)分子插入γ-丁内酯(GBL)的新反应合成内酯冠醚,用FTIR和ESI-MS对目标产物结构进行了确证.实验结果表明,LE-4催化剂的催化效果最佳;对反应温度和压力的优化实验进一步表明,当使用质量分数1%的LE-4催化剂,EO与GBL的摩尔比为5时,优化反应温度和体系压力分别为160℃和0.65 MPa,GBL转化率达到75.2%.

  7. 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.

  8. Modulation of the excited state intramolecular electron transfer reaction and dual fluorescence of crystal violet lactone in room temperature ionic liquids.

    Science.gov (United States)

    Santhosh, Kotni; Samanta, Anunay

    2010-07-22

    The influence of polarity, viscosity, and hydrogen bond donating ability of the medium on the fluorescence behavior of crystal violet lactone (CVL), which undergoes excited state electron transfer reaction and exhibits dual fluorescence from two different electronic states, termed as CT(A) and CT(B), has been studied in six different room temperature ionic liquids (ILs) using steady state and time-resolved emission techniques. It is shown that the excited state CT(A) --> CT(B) transformation and dual fluorescence of CVL can be controlled by appropriate choice of the ILs. While dual fluorescence of CVL is clearly observed in pyrrolidinium IL, the molecule exhibits a single fluorescence band in ammonium IL. While the second emission from the CT(B) state can barely be seen in 1,3-dialkylimidazolium ILs, dual fluorescence is quite prominent in 1-butyl-2,3-dimethylimidazolium IL, [bmMim][Tf(2)N]. These contrasting results have been explained taking into account the hydrogen bonding interactions of the 1,3-dialkylimidazolium ions (mediated through the C(2)-hydrogen) with CVL and the viscosity of the ILs. The excited state CT(A) --> CT(B) reaction kinetics has been studied in IL by monitoring the time-evolution of the CT(B) emission in [bmMim][Tf(2)N]. The solvation dynamics in this IL has been studied by following the dynamic fluorescence Stokes shift of C153, which is used as a probe molecule. A comparison of the excited state reaction time and solvation time suggests that the rate of the CT(A) --> CT(B) reaction in moderately viscous ILs is primarily dictated by the rate of solvation. Very little or negligible excitation wavelength dependence of the emission behavior of CVL can be observed in these ILs.

  9. Inuloxins A-D, phytotoxic bi-and tri-cyclic sesquiterpene lactones produced by Inula viscosa: potential for broomrapes and field dodder management.

    Science.gov (United States)

    Andolfi, Anna; Zermane, Nadjia; Cimmino, Alessio; Avolio, Fabiana; Boari, Angela; Vurro, Maurizio; Evidente, Antonio

    2013-02-01

    Four phytotoxic bi- and tri-cyclic sesquiterpene lactones, named inuloxins A-D, were isolated together with the known α-costic acid, from the aerial parts of Inula viscosa (family Asteraceae), a widespread Mediterranean plant well known for its content of pharmacologically active metabolites. The structures of inuloxins A-D were established by spectroscopic and chemical methods and determined to be: (4E,7R*,8R*,10S*)-3-oxo-germacra-4,11(13)-dien-8β-12-olide (A), its 11,13-dihydro analogue (B), (5R*,7R*,8R*,10R*)-1,15-methylene-5β-hydroxy-eudesm-1(15),11(13)-dien-8β-12-olide (C), and (7R*,8R*)-1,4-dimethyl-4-hydroxy-secoeudesm-5(10),11(13)-dien-8β-12-olide (D). The S absolute stereochemistry at C-5 of 5-hydroxyhexan-2-yl side chain of inuloxin D was assigned by applying an advanced Mosher's method. The phytotoxic activity of inuloxins A-D, that of the diazo and monoacetyl derivatives (of inuloxin A and C, resply), as well as that of α-costic acid was evaluated against two parasitic plant species, i.e. crenate broomrape (Orobanche crenata) and field dodder (Cuscuta campestris). Inuloxins A, C and D were the most active on both parasites and caused up to 100% inhibition of the seed germination. Inuloxin B was less active on Cuscuta and completely inactive against Orobanche. The main metabolite α-costic acid had a suppressive effect on the dodder seed germination but had a stimulating action on the broomrape seed germination. These preliminary results allowed to suppose some structure-activity relationships.

  10. A highly productive, whole-cell DERA chemoenzymatic process for production of key lactonized side-chain intermediates in statin synthesis.

    Directory of Open Access Journals (Sweden)

    Matej Ošlaj

    Full Text Available Employing DERA (2-deoxyribose-5-phosphate aldolase, we developed the first whole-cell biotransformation process for production of chiral lactol intermediates useful for synthesis of optically pure super-statins such as rosuvastatin and pitavastatin. Herein, we report the development of a fed-batch, high-density fermentation with Escherichia coli BL21 (DE3 overexpressing the native E. coli deoC gene. High activity of this biomass allows direct utilization of the fermentation broth as a whole-cell DERA biocatalyst. We further show a highly productive bioconversion processes with this biocatalyst for conversion of 2-substituted acetaldehydes to the corresponding lactols. The process is evaluated in detail for conversion of acetyloxy-acetaldehyde with the first insight into the dynamics of reaction intermediates, side products and enzyme activity, allowing optimization of the feeding strategy of the aldehyde substrates for improved productivities, yields and purities. The resulting process for production of ((2S,4R-4,6-dihydroxytetrahydro-2H-pyran-2-ylmethyl acetate (acetyloxymethylene-lactol has a volumetric productivity exceeding 40 g L(-1 h(-1 (up to 50 g L(-1 h(-1 with >80% yield and >80% chromatographic purity with titers reaching 100 g L(-1. Stereochemical selectivity of DERA allows excellent enantiomeric purities (ee >99.9%, which were demonstrated on downstream advanced intermediates. The presented process is highly cost effective and environmentally friendly. To our knowledge, this is the first asymmetric aldol condensation process achieved with whole-cell DERA catalysis and it simplifies and extends previously developed DERA-catalyzed approaches based on the isolated enzyme. Finally, applicability of the presented process is demonstrated by efficient preparation of a key lactol precursor, which fits directly into the lactone pathway to optically pure super-statins.

  11. Multi-seasonal barnacle (Balanus improvisus) protection achieved by trace amounts of a macrocyclic lactone (ivermectin) included in rosin-based coatings.

    Science.gov (United States)

    Pinori, Emiliano; Berglin, Mattias; Brive, Lena M; Hulander, Mats; Dahlström, Mia; Elwing, Hans

    2011-10-01

    Rosin-based coatings loaded with 0.1% (w/v) ivermectin were found to be effective in preventing colonization by barnacles (Balanus improvisus) both on test panels as well as on yachts for at least two fouling seasons. The leaching rate of ivermectin was determined by mass-spectroscopy (LC/MS-MS) to be 0.7 ng cm(-2) day(-1). This low leaching rate, as deduced from the Higuchi model, is a result of the low loading, low water solubility, high affinity to the matrix and high molar volume of the model biocide. Comparison of ivermectin and control areas of panels immersed in the field showed undisturbed colonisation of barnacles after immersion for 35 days. After 73 days the mean barnacle base plate area on the controls was 13 mm(2), while on the ivermectin coating it was 3 mm(2). After 388 days, no barnacles were observed on the ivermectin coating while the barnacles on the control coating had reached a mean of 60 mm(2). In another series of coated panels, ivermectin was dissolved in a cosolvent mixture of propylene glycol and glycerol formal prior to the addition to the paint base. This method further improved the anti-barnacle performance of the coatings. An increased release rate (3 ng cm(-2) day(-1)) and dispersion of ivermectin, determined by fluorescence microscopy, and decreased hardness of the coatings were the consequences of the cosolvent mixture in the paint. The antifouling mechanism of macrocyclic lactones, such as avermectins, needs to be clarified in further studies. Beside chronic intoxication as ivermectin is slowly released from the paint film even contact intoxication occurring inside the coatings, triggered by penetration of the coating by barnacles, is a possible explanation for the mode of action and this is under investigation.

  12. 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

  13. 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

  14. L-Galactono-1,4-lactone dehydrogenase is an assembly factor of the membrane arm of mitochondrial complex I in Arabidopsis.

    Science.gov (United States)

    Schimmeyer, Joram; Bock, Ralph; Meyer, Etienne H

    2016-01-01

    L-Galactono-1,4-lactone dehydrogenase (GLDH) catalyses the last enzymatic step of the ascorbate biosynthetic pathway in plants. GLDH is localised to mitochondria and several reports have shown that GLDH is associated with complex I of the respiratory chain. In a gldh knock-out mutant, complex I is not detectable, suggesting that GLDH is essential for complex I assembly or stability. GLDH has not been identified as a genuine complex I subunit, instead, it is present in a smaller, lowly abundant version of complex I called complex I*. In addition, GLDH activity has also been detected in smaller protein complexes within mitochondria membranes. Here, we investigated the role of GLDH during complex I assembly. We identified GLDH in complexes co-localising with some complex I assembly intermediates. Using a mutant that accumulates complex I assembly intermediates, we confirmed that GLDH is associated with the complex I assembly intermediates of 400 and 450 kDa. In addition, we detected accumulation of the 200 kDa complex I assembly intermediate in the gldh mutant. Taken together, our data suggest that GLDH is an assembly factor of the membrane arm of complex I. This function appears to be independent of the role of GLDH in ascorbate synthesis, as evidenced by the ascorbate-deficient mutant vtc2-1 accumulating wild-type levels of complex I. Therefore, we propose that GLDH is a dual-function protein that has a second, non-enzymatic function in complex I assembly as a plant-specific assembly factor. We propose an updated model for complex I assembly that includes complex I* as an assembly intermediate.

  15. A novel allele of L-galactono-1,4-lactone dehydrogenase is associated with enhanced drought tolerance through affecting stomatal aperture in common wheat.

    Science.gov (United States)

    Zhang, Juncheng; Li, Bin; Yang, Yanping; Mu, Peiyuan; Qian, Weiqiang; Dong, Lingli; Zhang, Kunpu; Liu, Xin; Qin, Huanju; Ling, Hongqing; Wang, Daowen

    2016-07-22

    In higher plants, L-galactono-1,4-lactone dehydrogenase (GLDH) plays important roles in ascorbic acid (AsA) biosynthesis and assembly of respiration complex I. Here we report three homoeologous genes (TaGLDH-A1, -B1 and -D1) encoding common wheat GLDH isozymes and a unique allelic variant (TaGLDH-A1b) associated with enhanced drought tolerance. TaGLDH-A1, -B1 and -D1 were located on chromosomes 5A, 5B and 5D, respectively, and their transcripts were found in multiple organs. The three homoeologs each conferred increased GLDH activity when ectopically expressed in tobacco. Decreasing TaGLDH expression in wheat significantly reduced GLDH activity and AsA content. TaGLDH-A1b differed from wild type allele TaGLDH-A1a by an in-frame deletion of three nucleotides. TaGLDH-A1b was biochemically less active than TaGLDH-A1a, and the total GLDH activity levels were generally lower in the cultivars carrying TaGLDH-A1b relative to those with TaGLDH-A1a. Interestingly, TaGLDH-A1b cultivars showed stronger water deficiency tolerance than TaGLDH-A1a cultivars, and TaGLDH-A1b co-segregated with decreased leaf water loss in a F2 population. Finally, TaGLDH-A1b cultivars generally exhibited smaller leaf stomatal aperture than TaGLDH-A1a varieties in control or water deficiency environments. Our work provides new information on GLDH genes and function in higher plants. TaGLDH-A1b is likely useful for further studying and improving wheat tolerance to drought stress.

  16. Tuning the degradation rate of calcium phosphate cements by incorporating mixtures of polylactic-co-glycolic acid microspheres and glucono-delta-lactone microparticles.

    Science.gov (United States)

    Sariibrahimoglu, Kemal; An, Jie; van Oirschot, Bart A J A; Nijhuis, Arnold W G; Eman, Rhandy M; Alblas, Jacqueline; Wolke, Joop G C; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Jansen, John A

    2014-11-01

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone graft materials in view of their excellent osteocompatibility and clinical handling behavior. Hydroxyapatite-forming CPCs, however, degrade at very low rates, thereby limiting complete bone regeneration. The current study has investigated whether degradation of apatite-forming cements can be tuned by incorporating acid-producing slow-resorbing poly(D,L-lactic-co-glycolic) acid (PLGA) porogens, fast-resorbing glucono-delta-lactone (GDL) porogens, or mixtures thereof. The physicochemical, mechanical, and degradation characteristics of these CPC formulations were systematically analyzed upon soaking in phosphate-buffered saline (PBS). In parallel, various CPC formulations were implanted intramuscularly and orthotopically on top of the transverse process of goats followed by analysis of the soft tissue response and bone ingrowth after 12 weeks. In vitro degradation of GDL was almost completed after 2 weeks, as evidenced by characterization of the release of gluconic acid, while PLGA-containing CPCs released glycolic acid throughout the entire study (12 weeks), resulting in a decrease in compression strength of CPC. Extensive in vitro degradation of the CPC matrix was observed upon simultaneous incorporation of 30% PLGA-10% GDL. Histomorphometrical evaluation of the intramuscularly implanted samples revealed that all CPCs exhibited degradation, accompanied by an increase in capsule thickness. In the in vivo goat transverse process model, incorporation of 43% PLGA, 30% PLGA-5% GDL, and 30% PLGA-10% GDL in CPC significantly increased bone formation and resulted in higher bone height compared with both 10% GDL and 20% GDL-containing CPC samples.

  17. Evolution of Enzymatic Activities in the Enolase Superfamily: Stereochemically Distinct Mechanisms in Two Families of cis,cis-Muconate Lactonizing Enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, A.; Fedorov, A; Fedorov, E; Schnoes, A; Glasner, M; Burley, S; Babbitt, P; Almo, S; Gerlt, J

    2009-01-01

    The mechanistically diverse enolase superfamily is a paradigm for elucidating Nature's strategies for divergent evolution of enzyme function. Each of the different reactions catalyzed by members of the superfamily is initiated by abstraction of the a-proton of a carboxylate substrate that is coordinated to an essential Mg2+. The muconate lactonizing enzyme (MLE) from Pseudomonas putida, a member of a family that catalyzes the syn-cycloisomerization of cis,cis-muconate to (4S)-muconolactone in the e-ketoadipate pathway, has provided critical insights into the structural bases for evolution of function within the superfamily. A second, divergent family of homologous MLEs that catalyzes anti-cycloisomerization has been identified. Structures of members of both families liganded with the common (4S)-muconolactone product (syn, Pseudomonas fluorescens, gi 70731221; anti, Mycobacterium smegmatis, gi 118470554) document that the conserved Lys at the end of the second e-strand in the (e/a)7e-barrel domain serves as the acid catalyst in both reactions. The different stereochemical courses (syn and anti) result from different structural strategies for determining substrate specificity: although the distal carboxylate group of the cis,cis-muconate substrate attacks the same face of the proximal double bond, opposite faces of the resulting enolate anion intermediate are presented to the conserved Lys acid catalyst. The discovery of two families of homologous, but stereochemically distinct, MLEs likely provides an example of 'pseudoconvergent' evolution of the same function from different homologous progenitors within the enolase superfamily, in which different spatial arrangements of active site functional groups and substrate specificity determinants support catalysis of the same reaction.

  18. Development and validation of a sensitive, simple, and rapid method for simultaneous quantitation of atorvastatin and its acid and lactone metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    Science.gov (United States)

    Macwan, Joyce S; Ionita, Ileana A; Dostalek, Miroslav; Akhlaghi, Fatemeh

    2011-04-01

    The aim of the proposed work was to develop and validate a simple and sensitive assay for the analysis of atorvastatin (ATV) acid, ortho- and para-hydroxy-ATV, ATV lactone, and ortho- and para-hydroxy-ATV lactone in human plasma using liquid chromatography-tandem mass spectrometry. All six analytes and corresponding deuterium (d5)-labeled internal standards were extracted from 50 μL of human plasma by protein precipitation. The chromatographic separation of analytes was achieved using a Zorbax-SB Phenyl column (2.1 mm × 100 mm, 3.5 μm). The mobile phase consisted of a gradient mixture of 0.1% v/v glacial acetic acid in 10% v/v methanol in water (solvent A) and 40% v/v methanol in acetonitrile (solvent B). All analytes including ortho- and para-hydroxy metabolites were baseline-separated within 7.0 min using a flow rate of 0.35 mL/min. Mass spectrometry detection was carried out in positive electrospray ionization mode, with multiple-reaction monitoring scan. The calibration curves for all analytes were linear (R(2) ≥ 0.9975, n = 3) over the concentration range of 0.05-100 ng/mL and with lower limit of quantitation of 0.05 ng/mL. Mean extraction recoveries ranged between 88.6-111%. Intra- and inter-run mean percent accuracy were between 85-115% and percent imprecision was ≤ 15%. Stability studies revealed that ATV acid and lactone forms were stable in plasma during bench top (6 h on ice-water slurry), at the end of three successive freeze and thaw cycles and at -80 °C for 3 months. The method was successfully applied in a clinical study to determine concentrations of ATV and its metabolites over 12 h post-dose in patients receiving atorvastatin.

  19. 比色法测定昆明山海棠片中总二萜内酯的含量%Determination the Content of Total Diterpene Lactones in Kunming Shan-haitang Tablets by Colorimetry

    Institute of Scientific and Technical Information of China (English)

    江银蒜; 刘岩庭; 吴春敏

    2015-01-01

    目的 建立测定昆明山海棠片中总二萜内酯含量的方法. 方法 采用比色法,在545nm波长处进行总二萜内酯的含量测定. 结果比色法测定昆明山海棠片总二萜内酯(以雷公藤甲素计)在8.17μg· mL-1 ~49.1μg· mL -1范围内线性关系良好(r=0.9999),平均加样回收率为99.2%,RSD为1.94%(n=6). 结论 本法简便、准确,适用于昆明山海棠片中总二萜内酯的含量测定,不同企业的昆明山海棠片中总二萜内酯的含量差异较大,在临床用药时应引起重视.%OBJECTIVE To determine the content of total diterpene lactones in Kunming Shanhaitang tab-lets.METHODS A colorimetric method was performed to determine the content of total diterpene lactones at 545nm.RESULTS The calibration curves were linear in the range from 8.17μg· mL-1 to 49.1μg· mL-1 (r=0.9999 ) for total diterpene lactones ( calculated as triptolide ) with colorimetric method.The average recovery rate (n=6) was 99.2%with RSD as 1.94%.CONCLUSION The method is simple and accurate,and can be used in the determination of Kunming Shanhaitang tablets.The content of total diterpene lactones in Kunming Shanhaitang tablets from different factories were compraratively largely disparity,which should be taken into account in clinic.

  20. Applied research of chitosan in processing of pressure lactone bean curd%壳聚糖在加压内酯豆腐加工中的应用研究

    Institute of Scientific and Technical Information of China (English)

    赵希荣; 王世亮; 邓成扣

    2012-01-01

    利用壳聚糖的增稠、凝胶和防腐作用性质,将其应用于加压内酯豆腐生产过程中。于添加壳聚糖前后,比较加压内酯豆腐相关性质,如失水性、保水性和贮藏性的变化情况。通过正交实验设计得到加压内酯豆腐的最佳生产工艺参数为:生豆浆浓度比为1:12,凝固剂葡萄糖酸内酯(GDL)用量为生豆浆质量的0.20%,壳聚糖用量为生豆浆质量的0.01%,点脑保温为70℃,凝固时间为30min。在该条件下生产出的加压内酯豆腐具有较好的持水性和水分含量,在5℃下保质期为21d,29.4℃条件下可保鲜24h。%Chitosan,based on its thickening,gelling and preservative effects,was applied on the processing of pressure lactone bean curd.The properties of pressure lactone bean curd in pre-and post-treatments,such as water loss,water holding capacity and storability,were determined.By the orthogonal test,the optimum technology parameters of pressure lactone bean curd was by as follows:concentration ratio of bean milk was 1:12,the amount of gluconic acid lactone coagulant(GDL) was 0.20% of bean milk,the amount of chitosan was 0.01% of bean milk,best coagulating temperature was 70℃,coagulating time was 30min.The product under the conditions exhibited better water holding capacity and moisture,while the shelf-life of bean curd at 5℃ and 29.4℃ reached 21 days and 24h,respectively.

  1. 变形链球菌UA159Pfs蛋白原核表达纯化及对自诱导分子2合成的影响%Expression and isolation of Streptococcus mutans UA159 S-adenosylhomocysteine nucleosidase protein and observation of its effect on synthesing autoinducer-2

    Institute of Scientific and Technical Information of China (English)

    黄英; 肖刚; 李芝香; 赵东方; 郭青玉

    2012-01-01

    Objective To further study the effect of induction molecule autoinducer-2 (AI-2) on the formation of oral biofilm,intending to synthesis Streptococcus mutuans (Sm) AI-2.Methods The prokaryotic expression vector pET21a (+)-pfs of Sm UA159 was constructed by the recombination technology.Then the recombinant vector was transformed into Escherichia coli B121 (DE3),and the expression of Pfs was optimized.The fusion protein was isolated by Ni-chelating column and identified by Western blotting.Then the protein was renatured by dialysis method.S-ribosylhomocysteine (SAH) was catalyzed by Pfs and S-ribosylhomocysteinase(LuxS) to synthesize AI-2.The reaction products induced the luminescence of Vibrio harveyi(Vh) BB170.When the concentration of Pfs protein decreased gradually,the intensity of luminescence emitted by Vh BB170 was observed.Results The recombinant plasmid was confirmed by restriction endonuclease digestion and sequence analysis,which showed that the inserted segment was identical to pfs gene reported by GenBank without nucleotide mutation.The maximum amount of the product expressed was obtained when the isopropylthio-β-D-galactoside (IPTG) concentration was 1 mmol/L,the optimal induction time was 4 h,and the concentration of Pfs was 0.80 g/L.The result of Western blotting showed that the product expressed was Pfs fusion protein.The recombinant Pfs and LuxS synthesized AI-2 in vitro.Up to 5 h,the luminescence intensity of Vh BB170 induced by AI-2 is the strongest [(815 522 ± 73 912) cd].The relative activity of AI-2 and the Pfs concentration are concentration-dependent (P < 0.05),with the rise of the Pfs protein concentration(0-0.38 g/L) the relative activity of AI-2 (0-29.14 ± 1.35) increased gradually(r =0.819,P =0.000).Conclusions The Pfs fusion protein had the biological function,catalyzed the synthesis of the signaling molecule AI-2.The result of the linear correlation analysis showed that the intensity of luminescence emitted by Vh BB170 induced by

  2. 1-Oxoeudesm-11(13)-eno-12,8a-lactone induces G2/M arrest and apoptosis of human glioblastoma cells in vitro

    Institute of Scientific and Technical Information of China (English)

    Shan-shan LIU; Yan-feng WANG; Li-sha MA; Bei-bei ZHENG; Lin LI; Wei-dong XiE; Xia LI

    2013-01-01

    Aim: To investigate the effects of 1-oxoeudesm-11(13)eno-12,8a-lactone (OEL),a novel eudesmane-type sesquiterpene isolated from Aster himalaicus,on the cell cycle and apoptosis in human glioblastoma cells in vitro.Methods: Human malignant glioblastoma cell lines U87 and A172 were used.The cytotoxicity of OEL was examined using the MTT assay.Cell apoptosis was assessed with DAPI staining and flow cytometry.DNA damage was determined by measuring the phosphorylation of H2AX using immunofluorescence staining and Western blotting.Cell cycle profiles were measured with flow cytometry.The mRNA expression of p53 and p21Waf1/Cip1 was investigated using real-time PCR.The protein expression of γ-H2AX,caspase-9,caspase-3,p53,p21Waf1/Cip1,cyclin B1,and cdc2 was analyzed with Western blotting.Results: Treatment of the malignant glioblastoma cells with OEL inhibited the cell growth in dose-and time-dependent manners (thevalues of IC50 at 48 and 72 h were 29.5 and 16.99 μmol/L,respectively,in U87 cells; 7.2 and 9.5 μmol/L,respectively,in A172 cells).OEL (10-30μmol/L) induced apoptosis and G2/M phase arrest in both U87 and A172 cells.OEL induced the phosphorylation of cdc2,a G2/M phase cyclin-dependent kinase,and decreased the expression of cyclin B1 required for progression through the G2/M phase in U87 cells.The compound remarkably increased the phosphorylation of H2AX in U87 cells.Moreover,OEL increased the mRNA and protein levels of p53 and its target gene p21waf1/cip1 in U87 cells.The compound also induced p53 phosphorylation.Pretreatment withPFT-α,a specific inhibitor of p53 transcriptional activity,could partially reverse the inhibition of OEL on the viability of U87 and A172 cells.Conclusion: OEL suppresses the growth of human glioblastoma cells in vitro via inducing DNA damage,p53-mediated cell cycle arrest and apoptosis,thus warrants further studies as a lead compound of anti-glioblastoma drug.

  3. 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.

  4. 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.

  5. Sesquiterpene lactone mix patch testing supplemented with dandelion extract in patients with allergic contact dermatitis, atopic dermatitis and non-allergic chronic inflammatory skin diseases.

    Science.gov (United States)

    Jovanović, M; Poljacki, M; Mimica-Dukić, N; Boza, P; Vujanović, Lj; Duran, V; Stojanović, S

    2004-09-01

    We investigated the value of patch testing with dandelion (Compositae) extract in addition to sesquiterpene lactone (SL) mix in selected patients. After we detected a case of contact erythema multiforme after patch testing with dandelion and common chickweed (Caryophyllaceae), additional testing with common chickweed extract was performed. A total of 235 adults with a mean age of 52.3 years were tested. There were 66 men and 169 women: 53 consecutive patients with allergic contact dermatitis (ACD); 43 with atopic dermatitis (AD); 90 non-atopics suffering from non-allergic chronic inflammatory skin diseases; 49 healthy volunteers. All were tested with SL mix 0.1% petrolatum (pet.) and diethyl ether extracts from Taraxacum officinale (dandelion) 0.1 and 3.0% pet. and from Stellaria media (common chickweed) 0.1 and 3% pet. A total of 14 individuals (5.9%) showed allergic reaction (AR) to at least 1 of the plant allergens, 4 (28.6%) to common chickweed extract, and 11 (78.6%) to Compositae allergens. These 11 persons made the overall prevalence of 4.7%: 8 (3.4%) were SL-positive and 3 (1.3%) reacted to dandelion extract. 5 persons (45.5%) had AD, 2 had ACD, 2 had psoriasis and 2 were healthy controls. The Compositae allergy was relevant in 8 cases (72.7%). The highest frequency of SL mix sensitivity (9.3%) was among those with AD. Half the SL mix-sensitive individuals had AD. ARs to dandelion extract were obtained only among patients with eczema. A total of 9 irritant reactions (IRs) in 9 individuals (3.8%) were recorded, 8 to SL mix and 1 to common chickweed extract 3.0% pet. No IR was recorded to dandelion extract (P = 0.007). Among those with relevant Compositae allergy, 50.0% had AR to fragrance mix and balsam of Peru (Myroxylon pereirae resin) and colophonium. SLs were detected in dandelion but not in common chickweed. Our study confirmed the importance of 1 positive reaction for emerging, not fully established, Compositae allergy. In conclusion, the overall

  6. 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.

  7. 丙型肝炎病毒核心蛋白通过自诱导方式可溶性表达及其生物学功能鉴定%The biological function of auto-induced expression of the hepatitis C virus soluble core protein

    Institute of Scientific and Technical Information of China (English)

    龚旭阳; 马其欢; 杜茜; 胡接力; 蔡雪飞; 黄爱龙

    2013-01-01

    Objective To investigate the biological role of auto-induced expression of hepatitis C virus (HCV) core protein (protein C) using a recombinant protein in an in vitro ceil-based system.Methods The PCR-amplified full-length HCV protein C gene (573 bp) was inserted into the pET28a prokaryotic expression vector.The recombinant plasmid was transformed into BL21 (DE3)pLysS E.coli to achieve high-concentration expression of the recombinant C protein by auto-induction.The recombinant protein C was purified by NiNTA affinity chromatography,and tested in a protein binding assay for its ability to bind the HCV NS3 protein.Results The transformed E.coli produced a large amount of recombinant protein C,as detected in the sonicated supernatant of the bacteria culture.The antigenic reactivity of the recombinant protein C was confirmed by western blotting.However,the recombinant protein C could not be purified by Ni-NTA affinity chromatography,but co-precipitated with the HCV NS3 protein.Conclusion Soluble recombinant protein C was successfully expressed by auto-induction,and shown to interact with the HCV NS3 protein,which provides a novel insight into the putative biological activity of this factor in HCV-related molecular processes.Future studies of this recombinant HCV protein C's crystal structure and antigenicity may provide further clues to its biological function(s) and potential for clinical applications.%目的 构建包含HCV核心蛋白全长基因的重组原核表达质粒,经转化表达型大肠杆菌后自诱导培养以获取可溶性重组核心蛋白,并检测其生物学功能. 方法 以H/FL质粒为模板,通过PCR扩增全长HCV核心蛋白DNA.PCR产物经双酶切后定向克隆到pET28a原核表达载体中.将重组的原核表达载体转化表达型大肠杆菌BL21 (DE3) pLysS,并通过自诱导培养的方式使其在高浓度状态下表达重组核心蛋白.重组核心蛋白经Western blot检测鉴定生物学功能,并与HCV NS3蛋白进行相

  8. Authentication of pineapple (Ananas comosus [L.] Merr.) fruit maturity stages by quantitative analysis of γ- and δ-lactones using headspace solid-phase microextraction and chirospecific gas chromatography-selected ion monitoring mass spectrometry (HS-SPME-GC-SIM-MS).

    Science.gov (United States)

    Steingass, Christof B; Langen, Johannes; Carle, Reinhold; Schmarr, Hans-Georg

    2015-02-01

    Headspace solid phase microextraction and chirospecific gas chromatography-mass spectrometry in selected ion monitoring mode (HS-SPME-GC-SIM-MS) allowed quantitative determination of δ-lactones (δ-C8, δ-C10) and γ-lactones (γ-C6, γ-C8, γ-C10). A stable isotope dilution assay (SIDA) with d7-γ-decalactone as internal standard was used for quantitative analysis of pineapple lactones that was performed at three progressing post-harvest stages of fully ripe air-freighted and green-ripe sea-freighted fruits, covering the relevant shelf-life of the fruits. Fresh pineapples harvested at full maturity were characterised by γ-C6 of high enantiomeric purity remaining stable during the whole post-harvest period. In contrast, the enantiomeric purity of γ-C6 significantly decreased during post-harvest storage of sea-freighted pineapples. The biogenetical background and the potential of chirospecific analysis of lactones for authentication and quality evaluation of fresh pineapple fruits are discussed.

  9. Thermochemistry of sesquiterpene lactone argolide

    Science.gov (United States)

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

    2017-01-01

    The enthalpies of dissolution of argolide (C15H20O3) in 96% ethanol are determined by isothermal calorimetry at 298.15 K and different dilutions of 1: 18 000, 1: 36 000, and 1: 72 000 (by mole). The standard enthalpy of dissolution of argolide in 96% ethanol is calculated from the obtained data: (86 ± 17) kJ mol-1. The temperature dependence of heat capacity of C15H20O3 is studied by means of dynamic calorimetry. An equation is derived to describe the C p 0 f ( T) dependence, and the standard heat capacity at 298.15 K is found to be (393 ± 13) J mol-1 K-1. The enthalpies of combustion, fusion and formation of argolide are calculated via approximation.

  10. Effect of Fritters with Lactone Formula Ingredients on Dough Rheological Properties%内酯油条配料对面团流变学性质的影响

    Institute of Scientific and Technical Information of China (English)

    傅琼颍; 李子廷; 赵建新; 张清苗; 庞珂; 范大明; 陈卫; 张灏

    2013-01-01

      Different proportions of lauric acid monoglycerides, yeast, calcium dihydrogen phosphate, gluconic acid-δ-lactone, high amylose corn starch and sodium bicarbonate were used as leavening agent for fritters and the effect of ingredients on dough rheological properties was studied. The results showed that sodium bicarbonate had the most significant impact on fairnograph and extensograph properties of dough and lauric acid monoglyceride and calcium dihydrogen phosphate increased the comprehensive modulus of dough (|G*|) significantly, increasing the dough viscoelasticity. High amylose corn starch, sodium bicarbonate and yeast significantly strengthened the role of the most compliance (Jmax) of dough and the recovery compliance (Jv). Gluconic acid-δ-lactone, and lauric acid monoglyceride significantly reduced the recovery ratio of dough (Jv/Jmax). When calcium dihydrogen phosphate addition was less than 2.5 g or glucono-δ-lactone addition was greater than 1.5 g , the viscousness of dough (μ0) was improved significantly.%  采用不同比例的月桂酸单甘酯、酵母、磷酸二氢钙、葡萄糖酸-δ-内酯、高直链玉米变性淀粉及碳酸氢钠作为内酯油条配料,研究各配料对面团流变学性质的影响。结果表明:碳酸氢钠对面团的粉质拉伸性质影响最为显著;月桂酸单甘脂和磷酸二氢钙能显著提高面团综合模量(|G*|),增加面团黏弹性;高直链玉米变性淀粉、碳酸氢钠和酵母对蠕变结束时面团的最大屈服应力(Jmax)及面团自由恢复后的屈服应力(Jv)有明显的加强作用;葡萄糖酸-δ-内酯和月桂酸单甘脂能显著减少面团的恢复比例(Jv/Jmax);磷酸二氢钙的添加量小于2.5 g或葡萄糖酸-δ-内酯的添加量大于1.5 g时,面团表面黏度(μ0)显著提高。

  11. Synthesis and biofilm inhibition evaluation of 5-acylated 3,4-dichloro-5H-furan-2-one as quorum sensing autoinducer analogs of Pseudomonas aeruginosa%铜绿假单胞菌群体感应信号分子类似物5-烷酸酯基-3,4-二氯-2(5H)-呋喃酮的合成及其生物膜抑制活性研究

    Institute of Scientific and Technical Information of China (English)

    杨晶晶; 孙平华; 陈卫民

    2012-01-01

    To study the biofilm inhibitor quorum sensing autoinducer analogs of Pseudomonas aeruginosa, the analogs of its quorum sensing antoinducer AHLs were synthesized. The 5-hydroxyl-3,4-dichloro-5H-furan-2-one was yielded from 2-furaldehyde, and then acylated at C-5 hydroxyl group with different length of alkyl acids. Eight target compounds were synthesized. All the compounds were confirmed by NMR and MS. The preliminary bioassay test indicated that compounds 2c, 2d, 2e, 2f and 2h showed remarkable effects on biofilm inhibition of Pseudomonas aeruginosa, especially compound 2e, inhibition ratio reached as high as 70% on ATCC 27853.%合成铜绿假单胞菌群体感应信号分子类似物作为细菌生物膜抑制剂.以呋喃甲醛为原料合成5-羟基-3,4-二氯-2(5H)-呋喃酮,与不同长度碳链的烷酸5-位成酯,合成了8个5-烷酸酯基-3,4-二氯-2(5H)-呋喃酮,其结构经NMR和MS表征.初步生物活性测试结果表明,化合物2c,2d,2e,2f和2h对铜绿假单胞菌生物膜的形成有明显的抑制作用,尤其是化合物2e,对ATCC 27853的生物膜抑制率高达70%以上.

  12. New phosphine-diamine and phosphine-amino-alcohol tridentate ligands for ruthenium catalysed enantioselective hydrogenation of ketones and a concise lactone synthesis enabled by asymmetric reduction of cyano-ketones

    Directory of Open Access Journals (Sweden)

    Fuentes José A

    2012-12-01

    Full Text Available Abstract Enantioselective hydrogenation of ketones is a key reaction in organic chemistry. In the past, we have attempted to deal with some unsolved challenges in this arena by introducing chiral tridentate phosphine-diamine/Ru catalysts. New catalysts and new applications are presented here, including the synthesis of phosphine-amino-alcohol P,N,OH ligands derived from (R,S-1-amino-2-indanol, (S,S-1-amino-2-indanol and a new chiral P,N,N ligand derived from (R,R-1,2-diphenylethylenediamine. Ruthenium pre-catalysts of type [RuCl2(L(DMSO] were isolated and then examined in the hydrogenation of ketones. While the new P,N,OH ligand based catalysts are poor, the new P,N,N system gives up to 98% e.e. on substrates that do not react at all with most catalysts. A preliminary attempt at realising a new delta lactone synthesis by organocatalytic Michael addition between acetophenone and acrylonitrile, followed by asymmetric hydrogenation of the nitrile functionalised ketone is challenging in part due to the Michael addition chemistry, but also since Noyori pressure hydrogenation catalysts gave massively reduced reactivity relative to their performance for other acetophenone derivatives. The Ru phosphine-diamine system allowed quantitative conversion and around 50% e.e. The product can be converted into a delta lactone by treatment with KOH with complete retention of enantiomeric excess. This approach potentially offers access to this class of chiral molecules in three steps from the extremely cheap building blocks acrylonitrile and methyl-ketones; we encourage researchers to improve on our efforts in this potentially useful but currently flawed process.

  13. Characterization of N-acylhomoserine lactone-degrading bacteria associated with the Zingiber officinale (ginger rhizosphere: Co-existence of quorum quenching and quorum sensing in Acinetobacter and Burkholderia

    Directory of Open Access Journals (Sweden)

    Chhabra Siri

    2011-03-01

    Full Text Available Abstract Background Cell-to-cell communication (quorum sensing (QS co-ordinates bacterial behaviour at a population level. Consequently the behaviour of a natural multi-species community is likely to depend at least in part on co-existing QS and quorum quenching (QQ activities. Here we sought to discover novel N-acylhomoserine lactone (AHL-dependent QS and QQ strains by investigating a bacterial community associated with the rhizosphere of ginger (Zingiber officinale growing in the Malaysian rainforest. Results By using a basal growth medium containing N-(3-oxohexanoylhomoserine lactone (3-oxo-C6-HSL as the sole source of carbon and nitrogen, the ginger rhizosphere associated bacteria were enriched for strains with AHL-degrading capabilities. Three isolates belonging to the genera Acinetobacter (GG2, Burkholderia (GG4 and Klebsiella (Se14 were identified and selected for further study. Strains GG2 and Se14 exhibited the broadest spectrum of AHL-degrading activities via lactonolysis while GG4 reduced 3-oxo-AHLs to the corresponding 3-hydroxy compounds. In GG2 and GG4, QQ was found to co-exist with AHL-dependent QS and GG2 was shown to inactivate both self-generated and exogenously supplied AHLs. GG2, GG4 and Se14 were each able to attenuate virulence factor production in both human and plant pathogens. Conclusions Collectively our data show that ginger rhizosphere bacteria which make and degrade a wide range of AHLs are likely to play a collective role in determining the QS-dependent phenotype of a polymicrobial community.

  14. Study Progress on Extraction and Separation Technology of Ginkgo Flavonoids and Terpene Lactones%银杏酮酯的提取分离技术研究进展

    Institute of Scientific and Technical Information of China (English)

    邵婷婷

    2016-01-01

    The flavonoids and terpene lactones are main active components of Ginkgo biloba leaves,which has been highly concerned because of its medicinal values.Effective extraction and separation of them has been drown attention internationally.In this paper,the main active ingredient and pharmacological effects of Ginkgo biloba were presented,the extraction and purification process of ginkgo flavonoids and terpene lactones were reviewed,the advantages and disadvantages of both technology were compared.In addition, the extraction and purification technology development trends were prospected.The results can provide references for more efficient and rational development of ginkgo extraction products.%银杏叶的主要活性成分为黄酮类化合物及萜内酯,因其具有很高的药用价值而受到广泛关注,如何对银杏酮酯进行有效的提取和分离一直是国内外关注的焦点.本文介绍了银杏叶的主要活性成分及药理作用,重点综述了近年来银杏酮酯提取及分离方面的新技术,对各类技术的优缺点进行比较,并对银杏酮酯提取分离技术的发展趋势进行了展望,以期为更高效合理地开发银杏酮酯产品提供参考.

  15. The involvement of bacterial quorum sensing in the spoilage of refrigerated Litopenaeus vannamei.

    Science.gov (United States)

    Zhu, Suqin; Wu, Haohao; Zeng, Mingyong; Liu, Zunying; Wang, Ying

    2015-01-02

    Quorum-sensing signals in refrigerated shrimp (Litopenaeus vannamei) undergoing spoilage were examined using bioreporter assays, thin-layer chromatography and gas chromatography-mass spectrometry, and the results revealed the presence of three types of autoinducers including acetylated homoserine lactones (AHLs) (i.e., N-hexanoyl-homoserine lactone, N-oxohexanoyl-homoserine lactone and N-octanoyl-homoserine lactone), autoinducer-2, and cyclic dipeptides (i.e., cyclo-(L-Pro-L-Leu), cyclo-(L-Leu-L-Leu) and cyclo-(L-Pro-L-Phe)). Autoinducer-2, rather than any AHL, was detected in extracts from pure cultures of the specific spoilage organisms (SSO), i.e., Shewanella putrefaciens (SS01) and Shewanella baltica (SA02). As for the cyclic peptides, only SA02 was determined to produce cyclo-(L-Pro-L-Leu). According to the transcription levels of LuxR (the master quorum-sensing regulator) in the SSO in response to exogenous autoinducers, the SSO could sense AHLs and cyclo-(L-Leu-L-Leu), rather than autoinducer-2, cyclo-(L-Leu-L-Leu) and cyclo-(L-Pro-L-Phe). In accordance with the results of LuxR expression, the production of biofilm matrixes and extracellular proteases in the SSO was regulated by exogenous AHLs and cyclo-(L-Pro-L-Leu), rather than 4,5-dihydroxy-2,3-pentanedione (the autoinducer-2 precursor), cyclo-(L-Leu-L-Leu) and cyclo-(L-Pro-L-Phe). Exogenous N-hexanoyl-homoserine lactone and cyclo-(L-Pro-L-Leu) increased the growth rates and population percentages of the SSO in shrimp samples under refrigerated storage, and interestingly, exogenous 4,5-dihydroxy-2,3-pentanedione also increased the population percentages of the SSO in vivo by inhibiting the growth of the competing bacteria. However, according to the levels of TVB-N and the volatile organic components in the shrimp samples, exogenous 4,5-dihydroxy-2,3-pentanedione did not accelerate the shrimp spoilage process as N-hexanoyl-homoserine lactone and cyclo-(L-Pro-L-Leu) did. In summary, our results suggest that

  16. 变形链球菌 UA159合成自诱导分子2及其影响因素的实验研究%In vitro biosynthesis of autoinducer 2 of Streptococcus mutans UA1 59 and observation of the influence factors

    Institute of Scientific and Technical Information of China (English)

    李芝香; 肖刚; 黄英; 赵东方; 刘飞; 刘阳; 郭青玉

    2015-01-01

    目的:原核表达纯化变形链球菌(S.mutans)UA159 LuxS 蛋白,体外合成有活性的自诱导分子2(AI-2)并观察其合成的影响因素。方法:用基因重组的方法构建表达载体 pET21 a(+)-luxS,在大肠杆菌(E.coli)BL21(DE3)中诱导表达 S-核糖基高半胱氨酸酶(LuxS)融合蛋白,镍柱亲和层析纯化、蛋白质印迹法分析鉴定 LuxS 蛋白,透析复性。纯化的 LuxS 蛋白和 S-腺苷高半胱氨酸核苷酶(Pfs)蛋白催化 S-腺苷 L 高半胱氨酸[SAH]合成 AI-2,哈氏弧菌 BB170检测 AI-2活性,并观察 LuxS 蛋白浓度、pH、氟化钠对 AI-2合成的影响。结果:与对照组相比,随着 LuxS 蛋白浓度的升高,体外合成的 AI-2活性增大(P <0.001);当 pH 介于6~10之间时,AI-2活性最强,超出此 pH 范围,AI-2活性明显降低(P <0.001);当氟化钠浓度≥0.3%时,AI-2活性显著降低(P <0.05)。结论:利用基因工程技术可以合成具有生物活性的 S.mutans UA159 AI-2;AI-2合成的最适 pH 在6~10之间;氟化钠浓度≥0.3%对 AI-2的合成有抑制作用。%Objective:To synthesize autoinducer-2 by the clone and prokaryotic expression of Streptococcus mutans(S.mutans)UAl59 luxS gene and to observe the influence factors.Methods:The expression vector pET21 a(+)-luxS of S.mutans UAl59 was transformed into Escheriehia coli BL2l(DE3).The S-ribosylhomocysteinase(Luxs)expression was induced by IPTG.The His tag fusion protein was isolated by Ni-chelating column and identified by Western blotting.Finally the protein was renatured by dialysis method.S-ribosylhomo-cysteine (SAH)was catalyzed by s-adenosylhomocysteine nucleosidas (Pfs)and LuxS,and then AI-2 was syntheszed.The AI-2 activi-ty was examined by luminescence of Vibrio harveyi BB1 70 when the concentration of LuxS protein or pH(4 -1 2)or the concentration of sodium fluoride was changed in reaction mixes of AI-2

  17. 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.

  18. 3-(4-Methyl-3-pentenyl)-2(5H)-furanone, alpha,alpha-acariolide and 4-(4-methyl-3-pentenyl)-2(5H)-furanone, alpha,beta-acariolide: new monoterpene lactones from the astigmatid mites, Schwiebea araujoae and Rhizoglyphus sp. (Astigmata: Acaridae).

    Science.gov (United States)

    Tarui, Hirokazu; Mori, Naoki; Nishida, Ritsuo; Okabe, Kimiko; Kuwahara, Yasumasa

    2002-01-01

    A new monoterpene lactone from the acarid mite, Schwiebea araujoae, was elucidated without its isolation by GC/FT-IR and GC/MS analyses to be 3-(4-methyl-3-pentenyl)-2(5H)-furanone (1) and tentatively named as alpha,alpha-acariolide. The structure of 1 was identified by its synthesis from alpha-bromo-gamma-butyrolactone via 4 reaction steps. The synthesized compound gave the same GC/MS and GC/FT-IR spectra as those of the natural product. The other monoterpene lactone was likewise elucidated from the unidentified Rhizoglyphus mite to be 4-(4-methyl-3-pentenyl)-2(5H)-furanone (2) and named as alpha,beta-acariolide; it was also identified by its synthesis in 5 reaction steps from the same butyrolactone as the starting material. GC/MS and GC/FT-IR spectra of the preparation were identical to those of the natural product.

  19. Research Progress in Chemical Components,Pharmacological Actions and Toxicity of Diterpene Lactones Isolated from Dioscoreae Bulbifera L.Rhizome%黄药子二萜内酯类成分化学、药理及毒性研究进展

    Institute of Scientific and Technical Information of China (English)

    王君明; 崔大鹏; 崔瑛

    2011-01-01

    Objective;To explore the research progress in chemical components,pharmacological actions and toxicity of diterpene lactones isolated from dioscoreae bulbifera L. Rhizome. Methods;The related information and references were looked through,and further analyzed and reviewed. Results;Up to now,the diterpene lactones isolated from D. Bulbifera rhizome mainly include diosbulbins A-M,8-epidios-bulbin E acetate,etc. Pharmacological references show that such diterpene lactones have effect on antitumor,anti-inflammation,antimicrobial and so on. However,they may induce hepatotoxicity. Conclusion;We should carry out further studies on dosage-effect relationship and mechanisms of the diterpene lactones isolated from D. Bulbifera rhizome, and finally to determine the safe and effective dose ranges so as to ensure the safety and validity in clinic application.%目的:探讨黄药予二萜内酯类成分化学、药理作用及毒性研究进展.方法:查阅国内外相关研究资料并进行汇总、分析、综述.结果:已发现的二萜内酯类成分主要有黄独素A-M、8-表黄独素乙酸酯等;二萜内酯类成分既是黄药子发挥抗肿瘤、抗炎、抗菌等作用的物质基础,也是其诱导肝毒性的毒性成分.结论:建议开展黄药子二萜内酯类成分的量效关系及作用机制研究,建立其安全有效的剂量范围,最终为其安全有效用药提供有意义的参考.

  20. HPLC-ELSD结合化学计量学研究银杏叶片中萜类内酯指纹图谱%Fingerprint Analysis of Terpene Lactones in Ginkgo Biloba Tablets by HPLC-ELSD Coupled with Chemometrics

    Institute of Scientific and Technical Information of China (English)

    吴雨龙; 李艳静; 王佩香; 丁岗; 李萍; 段金廒; 萧伟

    2013-01-01

    This study was aimed to establish a high performance liquid chromatography (HPLC) method coupled with Evaporative Light-scattering Detector (ELSD) in order to develop the determination of fingerprint of terpene lactones in Ginkgo biloba tablets. An Agilent Extend-C18 (4.6 mm í 250 mm, 5 μm) was employed as the analysis column and the normal propyl alcohol-tetrahydrofuran-water (1:15:84) as mobile phase. The column temperature was 30℃. And the flow rate was 1.0 mL·min-1. HPLC coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS) was used to identify the common peaks. The fingerprint was further evaluated by chemometrics methods including principal component analysis (PCA), similarity analysis (SA) and hierarchical clus-tering analysis (HCA). The results showed that the precision, stability and repeatability of this method were favorable. Five common peaks were identified by LC/Q-TOF MS as ginkgolide J ( M ) , C , A , B and bilobalide , respectively . Fourteen batches of Ginkgo biloba tablets were determined. With the aid of PCA, SA and HCA, the common pattern of the fingerprint of terpene lactones was established. Samples were divided into 4 clusters by their quality differ-ence. It was concluded that the method established in this paper can be used for quality evaluation of terpene lac-tones in G ink go b ilob a tablets.%目的:建立不同厂家银杏叶片中萜类内酯成分HPLC-ELSD指纹图谱。方法:色谱柱为Agi-lent Extend-C18(4.6 mm×250 mm,5μm),流动相为正丙醇-四氢呋喃-水(1、15、84),柱温为30℃,流速为1 mL·min-1,蒸发光散射检测器检测;采用LC/Q-TOF MS对指纹图谱中的共有峰进行指认。并利用化学计量学方法,包括主成分分析(PCA)、相似度分析(SA)、聚类分析(HCA),对色谱数据进行分析。结果:该方法精密度、稳定性、重复性良好。同时采用LC/Q-TOF MS方法指认了5个共有峰

  1. 安徽省不同产区不同栽培品种银杏叶总内酯含量的研究%Study on Content of the Total Terpene Lactones in Ginkgo Biloba L.Leaves from Various Area and Varieties in Anhui Province

    Institute of Scientific and Technical Information of China (English)

    周正华; 杜安全; 王先荣; 王德群; 刘守金; 梁益敏

    2013-01-01

    目的:研究安徽省不同产区和不同栽培品种银杏叶总内酯的含量.方法:采集安徽省6个产区不同品种银杏叶,分别测定其中总内酯的含量.结果:不同产区不同栽培品种银杏叶总内酯的含量差别较大.结论:可为安徽不同地区合理栽培银杏提供参考.%Objective:To study the content of total terpene lactones in Ginkgo biloba L. leaves from various area and varieties in Anhui province. Methods: Ginkgo biloba L. leaves were collected from six growth area in Anhui province, and the content of total terpene lactones were measured. Results: The contents of total terpene lactones were different in Ginkgo biloba L. leaves from various area and varieties. Conclusion: The result could provide scientific basis for rational planting of Ginkgo biloba L. in different areas of Anhui province.

  2. D-saccharic acid-1,4-lactone ameliorates alloxan-induced diabetes mellitus and oxidative stress in rats through inhibiting pancreatic beta-cells from apoptosis via mitochondrial dependent pathway

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Semantee [Department of Life Sciences and Biotechnology, Jadavpur University, 188, Raja S C Mullick Road, Kolkata 700 032 (India); Manna, Prasenjit [Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata-700054 (India); Gachhui, Ratan [Department of Life Sciences and Biotechnology, Jadavpur University, 188, Raja S C Mullick Road, Kolkata 700 032 (India); Sil, Parames C., E-mail: parames@bosemain.boseinst.ac.in [Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata-700054 (India)

    2011-12-15

    Oxidative stress plays a vital role in diabetic complications. To suppress the oxidative stress mediated damage in diabetic pathophysiology, a special focus has been given on naturally occurring antioxidants present in normal diet. D-saccharic acid 1,4-lactone (DSL), a derivative of D-glucaric acid, is present in many dietary plants and is known for its detoxifying and antioxidant properties. The aim of the present study was to evaluate the beneficial role of DSL against alloxan (ALX) induced diabetes in the pancreas tissue of Swiss albino rats. A dose-dependent study for DSL (20-120 mg/kg body weight) was carried out to find the effective dose of the compound in ALX-induced diabetic rats. ALX exposure elevated the blood glucose, glycosylated Hb, decreased the plasma insulin and disturbed the intra-cellular antioxidant machineries whereas oral administration of DSL at a dose of 80 mg/kg body weight restored these alterations close to normal. Investigating the mechanism of the protective activity of DSL we observed that it prevented the pancreatic {beta}-cell apoptosis via mitochondria-dependent pathway. Results showed decreased mitochondrial membrane potential, enhanced cytochrome c release in the cytosol and reciprocal regulation of Bcl-2 family proteins in the diabetic rats. These events were also found to be associated with increased level of Apaf-1, caspase 9, and caspase 3 that ultimately led to pancreatic {beta}-cell apoptosis. DSL treatment, however, counteracted these changes. In conclusion, DSL possesses the capability of ameliorating the oxidative stress in ALX-induced diabetes and thus could be a promising approach in lessening diabetic complications. Highlights: Black-Right-Pointing-Pointer Oxidative stress is suggested as a key event in the pathogenesis of diabetes. Black-Right-Pointing-Pointer D-saccharic acid 1,4-lactone (DSL) reduces the alloxan-induced diabetes mellitus. Black-Right-Pointing-Pointer DSL normalizes cellular antioxidant machineries

  3. D-Saccharic acid 1,4-lactone protects diabetic rat kidney by ameliorating hyperglycemia-mediated oxidative stress and renal inflammatory cytokines via NF-κB and PKC signaling

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Semantee [Department of Life Sciences and Biotechnology, Jadavpur University, 188, Raja S C Mullick Road, Kolkata 700 032 (India); Manna, Prasenjit [Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata-700054 (India); Gachhui, Ratan [Department of Life Sciences and Biotechnology, Jadavpur University, 188, Raja S C Mullick Road, Kolkata 700 032 (India); Sil, Parames C., E-mail: parames@bosemain.boseinst.ac.in [Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata-700054 (India)

    2013-02-15

    Increasing evidence suggests that oxidative stress is involved in the pathogenesis of diabetic nephropathy (DN) and this can be attenuated by antioxidants. D-Saccharic acid 1,4-lactone (DSL) is known for its detoxifying and antioxidant properties. Our early investigation showed that DSL can ameliorate alloxan (ALX) induced diabetes mellitus and oxidative stress in rats by inhibiting pancreatic β-cell apoptosis. In the present study we, therefore, investigated the protective role of DSL against renal injury in ALX induced diabetic rats. ALX exposure (at a dose of 120 mg/kg body weight, i. p., once) elevated the blood glucose level, serum markers related to renal injury, the production of reactive oxygen species (ROS), and disturbed the intra-cellular antioxidant machineries. Oral administration of DSL (80 mg/kg body weight) restored all these alterations close to normal. In addition, DSL could also normalize the aldose reductase activity which was found to increase in the diabetic rats. Investigating the mechanism of its protective activity, we observed the activation of different isoforms of PKC along with the accumulation of matrix proteins like collagen and fibronectin. The diabetic rats also showed nuclear translocation of NF-κB and increase in the concentration of inflammatory cytokines in the renal tissue. The activation of mitochondria dependent apoptotic pathway was observed in the diabetic rat kidneys. However, treatment of diabetic rats with DSL counteracted all these changes. These findings, for the first time, demonstrated that DSL could ameliorate renal dysfunction in diabetic rats by suppressing the oxidative stress related signalling pathways. - Highlights: ► Sustained hyperglycemia and oxidative stress lead to diabetic renal injury. ► D-saccharic acid 1,4-lactone prevents renal damage in alloxan-induced diabetes. ► It restores intra-cellular antioxidant machineries and kidney apoptosis. ► DSL reduces hyperglycemia-mediated oxidative stress

  4. Simultaneous Quantification of Flavonol Glycosides, Terpene Lactones, Biflavones, Proanthocyanidins, and Ginkgolic Acids in Ginkgo biloba Leaves from Fruit Cultivars by Ultrahigh-Performance Liquid Chromatography Coupled with Triple Quadrupole Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xin Yao

    2013-01-01

    Full Text Available On the basis of liquid chromatography coupled with triple quadrupole mass spectrometry working in multiple reaction monitoring mode, an analytical method has been established to simultaneously determine flavonol glycosides, terpene lactones, biflavones, proanthocyanidins, and ginkgolic acids in Ginkgo biloba leaves. Chromatographic separation was carried out on an Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm with gradient elution of acetonitrile and 0.10% formic acid (v/v at a flow rate of 0.4 mL/min, and column temperature 30°C. The developed method was validated in terms of linearity, accuracy, precision, stability, and sensitivity. The optimized method was successfully applied to analyze twenty-two G. biloba leaf samples of fruit cultivars collected from different places in China. Furthermore, hierarchical clustering analysis (HCA was performed to evaluate and classify the samples according to the contents of the twenty-four chemical constituents. All of the results demonstrated that the developed method was useful for the overall evaluation of the quality of G. biloba leaves, and this study was also helpful for the comprehensive utilization and development of G. biloba resources.

  5. 电解氧化法从葡萄糖制备D-葡萄糖酸-δ-内酯%Preparation of D-Gluconic Acid-S-Lactone by Electrolytic Oxidation of Glucose

    Institute of Scientific and Technical Information of China (English)

    周永江

    2011-01-01

    文章用自制压滤式电解槽对葡萄糖进行氧化电解制备D-葡萄糖酸-δ-内酯,对其工艺条件如电解质溶液、工作电流、分离、结晶条件等进行了一系列的探索和研究。结果表明,采用电解液外循环,控制一定的工作电流,可以得到较高产率的葡萄糖酸,再用电渗析方法分离葡萄糖和葡萄糖酸液溶液后,经过离子交换树脂,结晶,浓缩可以得到最终产物。%In the paper,D-gluconic acid-δ-lactone is Prepared from electrolytic oxidation of glucose by self-made filter press type electrolytic cell.Technological conditions such as electrolyte solution,operating current,separation and crystallization conditions are explored and researched.The results show that by external circulating electrolyte solution and by controlling certain operating current,more higher yields of gluconic acid can be obtained.After separating the glucose and gluconic acid solution by electrodialysis,the obtained acid solution through ion exchange resins is crystallined and then is concentrated to the final product.

  6. The Chemopreventive Effect of Tanacetum Polycephalum Against LA7-Induced Breast Cancer in Rats and the Apoptotic Effect of a Cytotoxic Sesquiterpene Lactone in MCF7 Cells: A Bioassay-Guided Approach

    Directory of Open Access Journals (Sweden)

    Hamed Karimian

    2015-06-01

    Full Text Available Background: Tanacetum polycephalum L. Schultz-Bip is a member of the Asteraceae family. This study evaluated the chemopreventive effect of a T. polycephalum hexane extract (TPHE using in in vivo and in vitro models. Methods and Results: Five groups of rats: normal control, cancer control, TPHE low dose, TPHE high dose and positive control (tamoxifen were used for the in vivo study. Histopathological examination showed that TPHE significantly suppressed the carcinogenic effect of LA7 tumour cells. The tumour sections from TPHE-treated rats demonstrated significantly reduced expression of Ki67 and PCNA compared to the cancer control group. Using a bioassay-guided approach, the cytotoxic compound of TPHE was identified as a tricyclic sesquiterpene lactone, namely, 8β- hydroxyl- 4β, 15- dihydrozaluzanin C (HDZC. Signs of early and late apoptosis were observed in MCF7 cells treated with HDZC and were attributed to the mitochondrial intrinsic pathway based on the up-regulation of Bax and the down-regulation of Bcl-2. HDZC induced cell cycle arrest in MCF7 cells and increased the expression of p21 and p27 at the mRNA and protein levels. Conclusion: This results of this study substantiate the anticancer effect of TPHE and highlight the involvement of HDZC as one of the contributing compounds that act by initiating mitochondrial-mediated apoptosis.

  7. The effects of N-acylhomoserine lactones, β-lactam antibiotics and adenosine on biofilm formation in the multi-β-lactam antibiotic-resistant bacterium Acidovorax sp. strain MR-S7.

    Science.gov (United States)

    Kusada, Hiroyuki; Hanada, Satoshi; Kamagata, Yoichi; Kimura, Nobutada

    2014-07-01

    Bacteria in the natural ecosystem frequently live as adherent communities called biofilms. Some chemical compounds are known to affect biofilm formation. We investigated the effect of exogenous small molecules, N-acylhomoserine lactones (AHLs), β-lactam antibiotics, and adenosine, on biofilm formation in the β-lactam antibiotic-resistant bacterium Acidovorax sp. strain MR-S7. Biofilm formation was induced by the addition of various types of AHL isomers and β-lactam antibiotics, whereas the addition of adenosine strongly interfered with the biofilm formation. A gene (macP) encoding adenosine deaminase (that converts adenosine to inosine controlling intracellular adenosine concentration) was successfully cloned from MR-S7 genome and heterologously expressed in Escherichia coli. The purified MacP protein clearly catalyzed the deamination of adenosine to produce inosine. A transcriptional analysis revealed that biofilm-inducing molecules, an AHL and a β-lactam antibiotic, strongly induced not only biofilm formation but also adenosine deaminase gene expression, suggesting that an elaborate gene regulation network for biofilm formation is present in the β-lactam antibiotic-resistant bacterium studied here.

  8. Mechanical and water-holding properties and microstructures of soy protein isolate emulsion gels induced by CaCl2, glucono-δ-lactone (GDL), and transglutaminase: influence of thermal treatments before and/or after emulsification.

    Science.gov (United States)

    Tang, Chuan-He; Chen, Ling; Foegeding, Edward Allen

    2011-04-27

    The mechanical properties, water-holding capacities (WHC), and microstructures of emulsion gels, induced by glucono-δ-lactone (GDL), CaCl(2), and microbial transglutaminase (MTGase) from unheated and heated soy protein isolate (SPI)-stabilized emulsions (at protein concentration 5%, w/v; oil volume fraction, 20%, w/v), were investigated and compared. The influence of thermal pretreatments (at 90 °C for 5 min) before and/or after emulsification was evaluated. Considerable differences in mechanical, water-holding, and microstructural properties were observed among various emulsion gels. The thermal pretreatment after emulsification increased the strength of the emulsion gels induced by GDL and CaCl(2), whereas in the case of MTGase, thermal pretreatments before and/or after emulsification on the contrary greatly inhibited gel network formation. The application of the enzyme coagulant exhibited much higher potential to form SPI-stabilized emulsion gels with higher mechanical strength than that of the other two coagulants. The WHC of the emulsion gels seemed to be not directly related to their gel network strength. Confocal laser scanning microscope analyses indicated that the network microstructure of the formed emulsion gels, mainly composed of aggregated protein-stabilized oil droplets and protein aggregate clumps, varied with the type of applied coagulants and emulsions. The differences in microstructure were basically consistent with the differences in mechanical properties of the gels. These results could provide valuable information for the formation of cold-set soy protein-stabilized emulsion gels.

  9. Modulation of Quorum Sensing in Acylhomoserine Lactone-Producing or -Degrading Tobacco Plants Leads to Alteration of Induced Systemic Resistance Elicited by the Rhizobacterium Serratia marcescens 90-166

    Directory of Open Access Journals (Sweden)

    Choong-Min Ryu

    2013-06-01

    Full Text Available Numerous root-associated bacteria (rhizobacteria are known to elicit induced systemic resistance (ISR in plants. Bacterial cell-density-dependent quorum sensing (QS is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90–166, in tobacco. Since S. marcescens 90–166 produces at least three QS signals, QS-mediated ISR in strain 90–166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum plants that contained either bacterial acylhomoserine lactone-producing (AHL or -degrading (AiiA genes in conjunction with S. marcescens 90–166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90–166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90–166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90–166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90–166.

  10. Modulation of Quorum Sensing in Acylhomoserine Lactone-Producing or -Degrading Tobacco Plants Leads to Alteration of Induced Systemic Resistance Elicited by the Rhizobacterium Serratia marcescens 90-166.

    Science.gov (United States)

    Ryu, Choong-Min; Choi, Hye Kyung; Lee, Chi-Ho; Murphy, John F; Lee, Jung-Kee; Kloepper, Joseph W

    2013-06-01

    Numerous root-associated bacteria (rhizobacteria) are known to elicit induced systemic resistance (ISR) in plants. Bacterial cell-density-dependent quorum sensing (QS) is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90-166, in tobacco. Since S. marcescens 90-166 produces at least three QS signals, QS-mediated ISR in strain 90-166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum) plants that contained either bacterial acylhomoserine lactone-producing (AHL) or -degrading (AiiA) genes in conjunction with S. marcescens 90-166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90-166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90-166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90-166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90-166.

  11. Simultaneous determination of six resorcylic acid lactones in feed using liquid chromatography-tandem mass spectrometry and multi-walled carbon nanotubes as a dispersive solid phase extraction sorbent.

    Science.gov (United States)

    Ying, Yong-Fei; Wu, Yin-Liang; Wen, Yi; Yang, Ting; Xu, Xiu-Qin; Wang, Yi-Zhen

    2013-09-13

    A simple and cost-effective pre-treatment procedure was developed for six resorcylic acid lactones (RALs) in feed using dispersive solid phase extraction (dSPE) with multi-walled carbon nanotubes (MWCNTs). The sample was analysed after purification by ultra-high performance liquid chromatography-negative electrospray ionisation tandem mass spectrometry (UHPLC-ESI-MS/MS). After extraction with acetonitrile/water (80:20, v/v) and dilution with water, a dSPE procedure was carried out with MWCNTs. The pH value of the extract, the extraction time for MWCNTs, the type and amount of MWCNTs and the type of eluent were optimised to increase the sample throughput and the sensitivity. The samples were quantified using the internal standard zearalenone-D6. The absolute recoveries of the target compounds from feed samples were most efficient when using 100mg of MWCNTs with an outer diameter of less than 8nm and a length of 10-30μm, and ethyl acetate was shown to be the most suitable solvent for desorbing the target compounds from the MWCNTs. The mean recoveries from fortified swine mixed feed samples ranged from 95.3% to 107.2% and had relative standard deviations lower than 10%; the limits of detection and quantification for RALs were in the ranges of 0.20-0.29μg/kg and 0.54-0.78μg/kg, respectively.

  12. Lysophosphatidic acid inhibition of the accumulation of Pseudomonas aeruginosa PAO1 alginate, pyoverdin, elastase and LasA

    DEFF Research Database (Denmark)

    Laux, D.C.; Corson, J.M.; Givskov, Michael Christian;

    2002-01-01

    The pathogenesis of Pseudomonas aeruginosa is at least partially attributable to its ability to synthesize and secrete the siderophore pyoverdin and the two zinc metal loproteases elastase and LasA, and its ability to form biofilms in which bacterial cells are embedded in an alginate matrix...... pyoverdin. MPPA also inhibited biofilm formation. The inhibitory effects of MPPA occur independently of rpoS expression and without affecting the accumulation of the autoinducers N-(3-oxododecanoyl) homoserine lactone and N-butyryl-(L)-homoserine lactone, and may be due, at least in part, to the ability...

  13. [Proteolytic control of expression of Vibrio fischeri lux-operon genes in Escherichia coli cells].

    Science.gov (United States)

    Mel'kina, O E; Manukhov, I V; Zavil'gel'skiĭ, G B

    2010-08-01

    The key elements of the regulatory system activating expression of the lux-operon genes in the sea bacteria Vibrio fischeri are the LuxR protein (an activator oftranscription) and N-(3-oxohexanoyl) L-homoserine lactone (an autoinducer, AI). It is shown that the ATP-dependent proteases ClpXP and Lon take part in the negative control of expression of the lux-operon genes and that AI protects the LuxR protein from proteolysis.

  14. Uso de lactonas macrocíclicas para el control de la garrapata Rhipicephalus (Boophilus microplus en el ganado bovino Use of macrocyclic lactones to control the cattle tick Rhipicephalus (Boophilus microplus

    Directory of Open Access Journals (Sweden)

    RI Rodríguez-Vivas

    2010-01-01

    Full Text Available En esta revisión se describe en detalle la composición química, farmacocinética, presentación y dosis, seguridad y tiempo de retiro y la seguridad ambiental de los grupos que componen a las LM: avemectinas (ivermectina, doramectina, eprinomectina, abamectina y milbemicinas (moxidectina. Además se presenta una discusión sobre su eficacia y el problema de resistencia de Rhipicephalus (Boophilus microplus a las LM. Se concluye que las LM por su alta liposolubilidad se distribuyen ampliamente en los tejidos, siendo eficaces para el control de R. (B. microplus en el ganado bovino. La eficacia de la ivermectina, doramectina, eprinomectina, abamectina y moxidectina de corta acción es similar (> 90% de eficacia a las cuatro semanas postratamiento, PT para el control de fases adultas de R. (B. microplus; sin embargo, existen en el mercado LM de larga acción que presentan eficacia > 95% con persistencia hasta 70 días PT.An overview of the macrocyclic lactones (ML, with recent results and their effect on the control of Rhipicephalus (Boophilus microplus, is presented in this paper. This review describes in detail the chemistry, pharmacokinetics and dose presentation, security and time withdrawal and environmental safety of the groups belonging to ML: avermectins (ivermectin, doramectin, eprinomectin, abamectin and milbemycin (moxidectin. There is also a discussion on their efficacy and the problem of resistance of R. (B. microplus to ML. Finally, it is concluded that due to their high lipid solubility ML are widely distributed in tissues, being effective in the control of R. (B. microplus in cattle. The efficacy of short-acting ivermectin, doramectin, eprinomectin, abamectin and moxidectin are similar (> 90% effective after four weeks post treatment, PT to control adult stages of R. (B. microplus, however, in long-acting LM are available the market and present efficiency of > 95% with persistence up to 70 days PT.

  15. Development of two step liquid-liquid extraction tandem UHPLC-MS/MS method for the simultaneous determination of Ginkgo flavonoids, terpene lactones and nimodipine in rat plasma: Application to the pharmacokinetic study of the combination of Ginkgo biloba dispersible tablets and Nimodipine tablets.

    Science.gov (United States)

    Xiao, Jie; Wang, Tianyang; Li, Pei; Liu, Ran; Li, Qing; Bi, Kaishun

    2016-08-15

    A sensitive, reliable and accurate UHPLC-MS/MS method has been firstly established and validated for the simultaneous quantification of ginkgo flavonoids, terpene lactones and nimodipine in rat plasma after oral administration of Ginkgo biloba dispersible tablets, Nimodipine tablets and the combination of the both, respectively. The plasma samples were extracted by two step liquid-liquid extraction, nimodipine was extracted by hexane-ether (3:1, v/v) at the first step, after that ginkgo flavonoids and terpene lactones were extracted by ethyl acetate. Then the analytes were successfully separated by running gradient elution with the mobile phase consisting of 0.1% formic acid in water and methanol at a flow rate of 0.6mL/min. The detection of the analytes was performed on a UHPLC-MS/MS system with turbo ion spray source in the negative ion and multiple reaction monitoring (MRM) mode. The calibration curves for the determination of all the analytes showed good linearity (R(2)>0.99), and the lower limits of quantification were 0.50-4.00ng/mL. Intra-day and inter-day precisions were in the range of 3.6%-9.2% and 3.2%-13.1% for all the analytes. The mean extraction recoveries of the analytes were within 69.82%-103.5% and the matrix were within 82.8%-110.0%. The validated method had been successfully applied to compare the pharmacokinetic parameters of ginkgo flavonoids, terpene lactones and nimodipine in rat plasma after oral administration of Ginkgo biloba dispersible tablets, Nimodipine tablets with the combination of the both. There were no statistically significant differences on the pharmacokinetic behaviors of all the analytes between the combined and single administration groups. Results showed that the combination of the two agents may avoid dosage adjustments in clinic and the combination is more convenient as well as efficient on different pathogenesis of cerebral ischemia.

  16. Effects of Fertilier and Drought Stress on Growth as well as Flavonol Glycosides and Terpene Lactone Content of Ginkgo Biloba Seedlings%施肥与干旱胁迫对银杏生长及黄酮苷和萜类内酯含量的影响

    Institute of Scientific and Technical Information of China (English)

    冷平生; 李月华; 苏淑钗; 王沙生; 蒋湘宁

    2001-01-01

    Effects of VAM fungi(Glomus mosseae and G versiforme)、N、P fertilizer and drought stress on the growth as well as flavonol glycosides and terpene lactone content of Ginkgo biloba seedlings were measured,experimental results showed that VAM fungi、N、P fertilizer obviously increased uptake of N、P elements,improved growth,enhanced terpene lactone content,drought stress decreased leaf water potencial and terpene lactone content of ginkgo biloba seedlings,those negative effects might be compensated by infection of host plants with both VAM fungi in some extent.Biosynthesis and metabolize of terpene lactones of ginkgo bilobamight be close relative to growth status of Ginkgo biloba seedlings.VAM fung;,N、P fertilizer drought stress had little effect on flavonol glycoside content of Ginkgo biloba.%对银杏实生苗接种VAM真菌,叶面喷施N、P肥及干旱胁迫处理,测定银杏生长及黄酮苷和萜类内酯含量的变化,试验结果表明:增施N、P肥能显著改善银杏植株N、P供应,增加银杏苗叶量和干重,显著提高银杏叶萜类内酯含量,而对银杏黄酮苷含量影响较小;干旱胁迫降低银杏叶水势和萜类内酯含量,对银杏黄酮苷含量没有影响,接种VAM真菌能减轻干旱胁迫的负影响,显著提高银杏萜类内酯含量。银杏萜类内酯的生物合成代谢与银杏生长状况密切相关。

  17. RING-OPENING POLYMERIZATION OF LACTONE IN THE PRESENCE OF BENZYL ALCOHOL CATALYZED BY ALIPHATIC TERTIARY AMINE%苄醇存在下脂肪叔胺催化内酯开环聚合

    Institute of Scientific and Technical Information of China (English)

    颜明发; 王涛; 黄永凯; 强娜; 全大萍

    2011-01-01

    In order to study the structure and the catalytic activity of aliphatic tertiary amines, the ring-opening polymerizations of trimethylene carbonate ( TMC ) and L-lactide ( L-LA) were catalyzed by aliphatic tertiary amines,including triethylamine ( TEA) , N, N, N', N'-tetramethylethylenediamine ( TMEDA ) , 1, 1,4,7, 7-pentamethyldiethylenetriamine (PMDTA) and 4-( dimethylamino) pyridine (DMAP) , using benzyl alcohol as initiator in THF at 551. Studies revealed the catalytic activity of these tertiary amines was increased according to the order; TEA < TMEDA ≈ PMDTA < DMAP. The relationships of polymer molecular weight with the conversion of monomer were linear, which were consistent with a living polymerization character. Finally, the plausible polymerization pathway was through an alcohol-activating mechanism. Aliphatic tertiary amines which were abundant in source and cheap in price were suitable for catalyzing the ring-opening bulk polymerization of lactone in low temperature because of their low boiling point, being liquid under ordinary conditions and being easy to get rid of.%为研究脂肪叔胺结构对内酯开环聚合规律的影响,以三乙胺( TEA)、N,N,N′,N′-四甲基乙二胺(TMEDA)、N,N,N′,N″,N″-五甲基二亚乙基三胺(PM DTA)3种不同结构的叔胺催化碳酸三亚甲基酯(TMC)和左旋丙交酯( L-LA)开环聚合.结果显示,在55℃的THF溶液中,以苄醇为引发剂,3种叔胺均能催化TMC和L-LA的开环聚合,聚合物的分子量与单体转化率成线性关系,表现出活性聚合特征.三者催化能力为TEA< TMEDA<PMDTA.对聚合物进行端基分析发现聚合反应可能是一个由醇活化机理引发的过程.

  18. 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

  19. 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.

  20. HPLC-ELSD法测定银杏酮酯软胶囊中萜类内酯的含量%Determination of Terpene Lactones in Yinxingtongzhi Soft Capsule by HPLC-ELSD Method

    Institute of Scientific and Technical Information of China (English)

    白娟; 张洁; 李成网

    2012-01-01

    A method for the determination of terpene lactones in Yinxingtongzhi soft capsules was established. HPLC-ELSD method was used in the quantitative analysis by using a Diamonsil C18 (250 mm×4.6 mm,5μm) column. The mobile phase was n-propanol-tetrahydrofuran-water( volume ratio was 1 : 25 : 74), ELSD evaporator tube temperature was 107℃, and air flow rate was 3.0 L/min. The calibration curve had good linear relationship in the range of 4.0088-20.0440,3.9284-19.6420,3.8348-19.1740,3.7888-30.3104μg for ginkgolide A, ginkgolide B, ginkgolide C and bilobalide, respectively (7=0.9992,0.9999,0.9995,0.9998). The recoveries were 98.48%,97.62%,97.54%,97.24%, and RSD were 0.99%, 1.13%, 1.17%,0.83%(n=5), respectively. This method was accurate and reliable, it can be used for the quality control of Yinxingtongzhi soft capsules.%建立银杏酮酯软胶囊中萜类内酯含量的测定方法.采用HPLC-ELSD法,色谱条件为Diamonsil C18柱(250 mm× 4.6 mm,5 μm),正丙醇-四氢呋喃-水(体积比1∶25∶74)为流动相,ELSD漂移管温度107℃,空气流速3.0L/min.银杏内酯A、银杏内酯B、银杏内酯C、白果内酯分别在4.008 8~20.0440,3.928 4~19.6420,3.8348~19.1740,3.788 8~30.3104μg范围内呈良好的线性关系,线性相关系数分别为0.9992,0.9999,0.9995,0.9998,回收率分别为98.48%,97.62%,97.54%,97.24%,测定结果的相对标准偏差分别为0.99%,1.13%,1.17%,0.83%(n=5).该方法准确可靠,可用于银杏酮酯软胶囊的质量控制.

  1. Quorum Quenching Bacillus sonorensis Isolated from Soya Sauce Fermentation Brine

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2012-03-01

    Full Text Available An N-acylhomoserine lactone (AHL-degrading bacterial strain, L62, was isolated from a sample of fermentation brine of Chinese soya sauce by using rich medium agar supplemented with soya sauce (10% v/v. L62, a rod-shaped Gram positive bacterium with amylolytic activity, was phylogentically related to Bacillus sonorensis by 16S ribosomal DNA and rpoB sequence analyses. B. sonorensis L62 efficiently degraded N-3-oxohexanoyl homoserine lactone and N-octanoylhomoserine lactone. However, the aiiA homologue, encoding an autoinducer inactivation enzyme catalyzing the degradation of AHLs, was not detected in L62, suggesting the presence of a different AHL-degrading gene in L62. To the best of our knowledge, this is the first report of AHL-degrading B. sonorensis from soya sauce liquid state fermentation.

  2. Convenient synthesis of volatile streptomyces lactones

    Digital Repository Service at National Institute of Oceanography (India)

    Amonkar, C.P.; Tilve, S.G.; Parameswaran, P.S.

    A convenient three-step synthetic approach towards 3-alkyl-5-methyl-2[5 H]furanones is described. The steps involved in the synthesis are domino primary alcohol oxidation-Wittig reaction, acid-catalysed lactonisation and isomerisation. This synthetic...

  3. Quorum sensing signaling molecules produced by reference and emerging soft-rot bacteria (Dickeya and Pectobacterium spp..

    Directory of Open Access Journals (Sweden)

    Alexandre Crépin

    Full Text Available BACKGROUND: Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. METHODOLOGY/PRINCIPAL FINDINGS: Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. CONCLUSIONS/SIGNIFICANCE: Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also

  4. Quorum Sensing Signaling Molecules Produced by Reference and Emerging Soft-Rot Bacteria (Dickeya and Pectobacterium spp.)

    Science.gov (United States)

    Crépin, Alexandre; Barbey, Corinne; Beury-Cirou, Amélie; Hélias, Valérie; Taupin, Laure; Reverchon, Sylvie; Nasser, William; Faure, Denis; Dufour, Alain; Orange, Nicole; Feuilloley, Marc; Heurlier, Karin; Burini, Jean-François; Latour, Xavier

    2012-01-01

    Background Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. Methodology/Principal Findings Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. Conclusions/Significance Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the

  5. Paniculta lactone dropping pill for treatment of sore throat caused by upper respiratory tract infection%穿心莲内酯滴丸治疗上呼吸道感染所致咽喉肿痛85例疗效评价

    Institute of Scientific and Technical Information of China (English)

    徐国荣

    2016-01-01

    目的观察评价穿心莲内酯滴丸对上呼吸道感染所致风热症咽喉肿痛的治疗作用与效果。方法观察170例对症患者,随机分为穿心莲内酯滴丸治疗组(A组)85例、罗红霉素胶囊对照组(B组)85例。连续用药5~7 d,观察用药后1、3和5 d各组症状积分变化与各时间点的关系。结果 A、B组5 d治愈数分别为29例(34.12%)、11例(12.94%),A组与B组之间差异有统计学意义(<0.050),A组症状积分的改善优于B组。结论穿心莲内酯滴丸在治疗上呼吸道感染所致风热证咽喉肿痛及其他症状的缓解方面有独特的疗效,且副作用小,安全系数高,值得推广使用。%Objective To observe the effect of Paniculta lactone dropping pill for the treatment of wind-fever sore throat caused by upper respiratory tract infection. Methods Totally 170 cases of symptomatic pa_tients were randomly divided into Paniculta lactone dropping pill treatment group (group A, 85 cases) and Roxithromycin capsule control group (group B, 85 cases). The patients had continuous drug administration for 5-7 days. Symptom integral changes were observed 1, 3 and 5 days after medication and compared between both groups. Results The 5-day cure-number in the groups A and B was 29 cases (34.12%) and 11 cases (12.94%) respectively, there was a statistically significant difference between them ( <0.05); the symptom in_tegral in the group A was improved more than that in the group B. Conclusions Paniculta lactone dropping pill has unique curative effect in the treatment of wind-heat syndrome sore throat caused by upper respiratory tract infection and relief of other symptoms, but it has few side effects and high safety coefficient, and is worthy of promotion of use.

  6. The Influence of Ginkgo Terpene Lactones Meglumine Injection on Blood Hemorheology in Patients with Cerebral Infarction at Conva-lescence%银杏二萜内酯葡胺注射液对脑梗死恢复期患者血液流变学的影响

    Institute of Scientific and Technical Information of China (English)

    肖展翅; 倪小红; 李钢; 高聚; 陈洪汉

    2015-01-01

    Objective To investigate the effect of Ginkgo terpene lactones meglumine injection on blood hemorheology in patients with cerebral infarction at convalescence.Methods Sixty seven patients with cerebral infarction convalescence were randomly divided into two groups:The control group(n=33)treated with routine treatment,and the treatment group(n=34)treated with routine treat-ment plus Ginkgo terpene lactones meglumine injection for 2 weeks.The changes of blood rheology,nerve function defect score and side effects were observed after 2 weeks.Results After treatment,the changes of blood rheology and nerve function defect score in treatment group were better than that before treatment and in control group(P<0.05).Conclusion Ginkgo terpene lactones meglu-mine injection has good and safe effects in patients with cerebral infarction at convalescence.%目的:观察银杏二萜内酯葡胺注射液对动脉粥样硬化性血栓性脑梗死恢复期患者血液流变学的影响。方法将67例动脉粥样硬化性血栓性脑梗死恢复期患者随机分为两组。对照组33例,予西医常规治疗;治疗组34例,在对照组治疗的基础上加用银杏二萜内酯葡胺注射液静脉输注。两组均治疗2周。观察比较两组患者治疗前后血液流变学、神经功能缺损评分的变化,以及不良反应发生情况。结果治疗后,治疗组血液流变学及神经功能缺损评分改善优于治疗前与对照组(P<0.05),不良反应轻微。结论银杏二萜内酯葡胺注射液具有活血通络之功效,是治疗脑梗死安全有效的药物。

  7. Regioselective intramolecular ring closure of 2-amino-6-bromo-2,6-dideoxyhexono-1,4-lactones to 5- or 6-membered iminuronic acid analogues:synthesis of 1-deoxymannojirimycin and 2,5-dideoxy-2,5-imino-D-glucitol

    DEFF Research Database (Denmark)

    Malle, Birgitte Mølholm; Lundt, Inge; Wrodnigg, Tanja M.

    2008-01-01

    the corresponding six-membered ring 1,5-iminuronic acid mimetics, namely (2R,3R,4S,5R)-3,4,5-trihydroxypipecolic acid (2,6-dideoxy-2,6- imino-D-galactonic acid, 16) and (2S,3R,4S,5R)-3,4,5-trihydroxypipecolic acid (2,6-dideoxy-2,6- imino-D-talonic acid, 17), were obtained. The corresponding enantiomers, L......-galacto- as well as L-talo-2-amino-6-bromo-2,6-dideoxy-1,4-lactones ent-14 and ent-15, reacted accordingly to give the D-galacto- and L-altro-1,5-iminuronic acid mimetics, (2S,3S,4R,5S)-3,4,5-trihydroxypipecolic acid (2,6-dideoxy-2,6-imino-L-galactonic acid, ent-16) and (2R,3S,4R,5S)-3,4,5-trihydroxypipecolic...

  8. Stereochemical insignificance discovered in Acinetobacter baumannii quorum sensing.

    Directory of Open Access Journals (Sweden)

    Amanda L Garner

    Full Text Available Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl-L-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a case of stereochemical insignificance in A. baumannii and provide a unique example where stereochemistry appears nonessential for acylhomoserine lactone-mediated quorum sensing signaling. Based on previously reported phylogenetic studies, we suggest that A. baumannii has evolutionarily adopted this unique, yet promiscuous quorum sensing system to ensure its survival, particularly in the presence of other proteobacteria.

  9. RP-HPLC法测定银杏叶提取物类脂质体中黄酮和萜类内酯含量的优化方法%Quantitative Determination of Flavonol Glycosides and Terpene Lactones from Ginkgo Leaf Extract Noisome

    Institute of Scientific and Technical Information of China (English)

    崔大明; 金叶; 周毓麟; 李玉环; 郭璇; 滕利荣; 张炜煜

    2013-01-01

    The aim of this study was to develop a simple and accurate isocratic RP-HPLC analytical method to qualify and quantify three flavonol glycosides (Quercetin,Kaempferol and Isorhamnetin) and four terpene lactones (Ginkgolide A,Ginkgolide B,Ginkgolide C and Bilobalide) of ginkgo leaf extract.The contents of flavonoid glycosides and terpene lactones from EGBN were measured by dialysis method.And the saturation solubility of flavonoid glycosides was also measured with this HPLC method.The condition of HPLC method for flavonol glycosides is:column:Agilent HC-C18 (4.6 mm× 250.0 mm,5 μm) ; mobile phase:ACN-0.4% phosphoric acid (28∶72,v/v).The drug elution was performed at 40 ℃ at a flow rate of 1.0 mL/min and detected at the wavelength of 360 nm.And the condition of HPLC method for terpene lactones is:column:Agilent HC-C18 (250.0 mm × 4.6 mm,5μn) ; mobile phase:Methonal-THF-Water (46∶7∶47,v/v/v).The flow rate was kept at 0.8 mL/min.The temperature of NEB and EVA was performed at 60 ℃ and 105 ℃,respectively.The HPLC methods for flavonol glycosides and terpene lactones were shown to be linear,precise,sensitive,selective and accurate.And the contents of flavonoid glycosides and terpene lactones from EGBN can be measured by dialysis method.%建立反相高效液相色谱法(RP-HPLC),测定银杏叶提取物类脂质体(EGBN)中银杏3种黄酮化合物(槲皮素、山奈素、异鼠李素)和4种萜类内酯(银杏内酯A、银杏内酯B、银杏内酯C、白果内酯)的含量,及银杏总黄酮醇苷的饱和溶解度.采用透析法提取出EGBN中的银杏黄酮.黄酮应用Agilent HC-C18色谱柱(4.6 mm× 250.0 mm,5μm),以V(乙腈)∶V(0.4%磷酸)=28∶72为流动相,流速1.0 mL/min,检测波长360nm,柱温40℃.萜类内酯应用Agilent HC-C18色谱柱(4.6 mm×250.0 mm,5μm),以V(甲醇)∶V(四氢呋喃)∶V(水)=46∶7∶47为流动相,流速0.8 mL/min,NEB温度60℃,EVA温度105℃.结果表明:透析法可以将EGBN中有效成分很好的分

  10. Modulating Vibrio cholerae quorum-sensing-controlled communication using autoinducer-loaded nanoparticles.

    Science.gov (United States)

    Lu, Hoang D; Spiegel, Alina C; Hurley, Amanda; Perez, Lark J; Maisel, Katharina; Ensign, Laura M; Hanes, Justin; Bassler, Bonnie L; Semmelhack, Martin F; Prud'homme, Robert K

    2015-04-08

    The rise of bacterial antibiotic resistance has created a demand for alternatives to traditional antibiotics. Attractive possibilities include pro- and anti-quorum sensing therapies that function by modulating bacterial chemical communication circuits. We report the use of Flash NanoPrecipitation to deliver the Vibrio cholerae quorum-sensing signal CAI-1 ((S)-3-hydroxytridecan-4-one) in a water dispersible form as nanoparticles. The particles activate V. cholerae quorum-sensing responses 5 orders of magnitude higher than does the identically administered free CAI-1 and are diffusive across in vivo delivery barriers such as intestinal mucus. This work highlights the promise of combining quorum-sensing strategies with drug delivery approaches for the development of next-generation medicines.

  11. Activity of autoinducer two (AI-2) in bacteria isolated from surface ripened cheeses

    DEFF Research Database (Denmark)

    Gori, Klaus; Jespersen, Lene

    ). Corynebacterium casei, Microbacterium barkeri, Microbacterium gubbeenense and S. equorum subsp. linens (all isolated from the smear of surface ripened cheeses) using the AI-2 bioluminescence assay. This indicates that AI-2 signaling could take place between bacteria found in the smear of surface ripened cheeses....

  12. Activity of autoinducer two (AI-2) in bacteria isolated from surface ripened cheeses

    DEFF Research Database (Denmark)

    Gori, Klaus; Jespersen, Lene

    2007-01-01

    ). Corynebacterium casei, Microbacterium barkeri, Microbacterium gubbeenense and S. equorum subsp. linens (all isolated from the smear of surface ripened cheeses) using the AI-2 bioluminescence assay. This indicates that AI-2 signaling could take place between bacteria found in the smear of surface ripened cheeses....

  13. Autoinducer-2 activity produced by bacteria found in smear of surface ripened cheeses

    DEFF Research Database (Denmark)

    Gori, Klaus; Moslehi Jenabian, Saloomeh; Purrotti, Micol

    2011-01-01

    -2) activity using the Vibrio harveyi (BB170) bioluminescence assay. In contrast, Brevibacterium casei and Brevibacterium linens strains were not found to have AI-2 activity. When exposed to low pH and high NaCl concentrations, AI-2 activities increased between 5.0 and 11.6× for C. casei 44701, M...

  14. Construction of a Cell Based Sensor for the Detection of Autoinducer-2 (Reprint)

    Science.gov (United States)

    2012-09-01

    Zhu J, Miller M.B., Vance R.E., Dziejman M, Bassler B.L., “Quorum-sensing regulators control virulence gene expression in Vibrio cholerae ,” Proc...The assay utilizes the reporter strain Vibrio harveyi BB170, a mutant strain of V. harveyi which does not produce AI-2, which produces...expression of luminescence in Vibrio harveyi: sequence and function of genes encoding a second sensory pathway,” Mol. Microbiol. 13: 273–286 (1994). [6

  15. Fimbrolide Natural Products Disrupt Bioluminescence of Vibrio By Targeting Autoinducer Biosynthesis and Luciferase Activity.

    Science.gov (United States)

    Zhao, Weining; Lorenz, Nicola; Jung, Kirsten; Sieber, Stephan A

    2016-01-18

    Vibrio is a model organism for the study of quorum sensing (QS) signaling and is used to identify QS-interfering drugs. Naturally occurring fimbrolides are important tool compounds known to affect QS in various organisms; however, their cellular targets have so far remained elusive. Here we identify the irreversible fimbrolide targets in the proteome of living V. harveyi and V. campbellii via quantitative mass spectrometry utilizing customized probes. Among the major hits are two protein targets with essential roles in Vibrio QS and bioluminescence. LuxS, responsible for autoinducer 2 biosynthesis, and LuxE, a subunit of the luciferase complex, were both covalently modified at their active-site cysteines leading to inhibition of activity. The identification of LuxE unifies previous reports suggesting inhibition of bioluminescence downstream of the signaling cascade and thus contributes to a better mechanistic understanding of these QS tool compounds.

  16. Autoinduced catalysis and inverse equilibrium isotope effect in the frustrated Lewis pair catalyzed hydrogenation of imines.

    Science.gov (United States)

    Tussing, Sebastian; Greb, Lutz; Tamke, Sergej; Schirmer, Birgitta; Muhle-Goll, Claudia; Luy, Burkhard; Paradies, Jan

    2015-05-26

    The frustrated Lewis pair (FLP)-catalyzed hydrogenation and deuteration of N-benzylidene-tert-butylamine (2) was kinetically investigated by using the three boranes B(C6F5)3 (1), B(2,4,6-F3-C6H2)3 (4), and B(2,6-F2-C6H3)3 (5) and the free activation energies for the H2 activation by FLP were determined. Reactions catalyzed by the weaker Lewis acids 4 and 5 displayed autoinductive catalysis arising from a higher free activation energy (2 kcal mol(-1)) for the H2 activation by the imine compared to the amine. Surprisingly, the imine reduction using D2 proceeded with higher rates. This phenomenon is unprecedented for FLP and resulted from a primary inverse equilibrium isotope effect.

  17. Mechanistic insights into the LsrK kinase required for autoinducer-2 quorum sensing activation

    OpenAIRE

    Zhu, Jie; Hixon, Mark S.; Globisch, Daniel; Kaufmann, Gunnar F.; Janda, Kim D.

    2013-01-01

    In enteric bacteria, the kinase LsrK catalyzes the phosphorylation of the C5-hydroxyl group in the linear form of 4,5-dihydroxy-2,3-pentanedione (DPD), the precursor of the type II bacterial quorum sensing molecule (AI-2). This phosphorylation is required for AI-2 sequestration in the cytoplasm and subsequent derepression of AI-2 related genes necessary for quorum development. While LsrK is a critical enzyme within the DPD quorum sensing relay system, kinetic details of this kinase have yet t...

  18. Effect of coriaria lactone on adenosine triphosphate-sensitive potassium channels in pyramidal neurons%马桑内酯对锥体神经元三磷酸腺苷敏感钾通道的作用

    Institute of Scientific and Technical Information of China (English)

    邹晓毅; 周华; 周树舜

    2005-01-01

    BACKGROUND: Abnormal neuronal discharge arose from the activation of cell membrane ion channels and transmembrane ion transport. The electric activity of the cells is associated with cell metabolism fundamentally through adenosine triphosphate (ATP)-sensitive potassium(KATP) channels.Currently the involvement of KATP channels in the pathogenesis of epilepsy and the regulation of KATP channels by coriaria lacton (EL) remain unknown.OBJETCIVE: To investigate the changes of cell membrane KATP channels in rat hippocampal neurons in response to CL as an epilepsy-inducing agent, and explore the role of KATP channels in the pathogenesis of epilepsy.DESIGN: Randomized controlled experiment.SETTING: Department of Neurology, West China Hospital Affiliated to Sichuan University, and Teaching and Research Section of Physiology,West China College of Preclinical Medicine and Forensic Medicine of Sichuan University.MATERIALS: This experiment was carried out at Luzhou Medical College between May and December 2000. Hippocampus pyramidal neurons were obtained from neonatal Wistar rats and randomized into normal control group, tetraethylammonium chloride (TEA) group, DNP group, CL group, and electric conductance and dynamics group.METHODS: The hippocampus of newborn Wistar rats was separated under aseptic condition and cultured for 24 hours prior to treatment with 10 μmol/L cytarabine for selective cell culture for 7-10 days. The cells in good growth exhibiting typical morphology of pyramidal neurons were then selected for patch-clamp experiment. The cells in the normal control group were treated with normal saline, which was replaced by 5 mmol/L TEA in TEA group, by 30 μmol/L DNP then 0.5 mol/L ATP in DNP group, and by 1.0 mL/L CL then 1 μmol/L glibenclamide in CL group. In electric conductance and dynamics group, the clamp voltage was firstly adjusted to investigate the channel opening before CL was added to the cells.MAIN OUTCOME MEASURES: ① Activity and curve of neuronal

  19. Efficient and selective formation of macrocyclic disubstituted Z alkenes by ring-closing metathesis (RCM) reactions catalyzed by Mo- or W-based monoaryloxide pyrrolide (MAP) complexes: applications to total syntheses of epilachnene, yuzu lactone, ambrettolide, epothilone C, and nakadomarin A.

    Science.gov (United States)

    Wang, Chenbo; Yu, Miao; Kyle, Andrew F; Jakubec, Pavol; Dixon, Darren J; Schrock, Richard R; Hoveyda, Amir H

    2013-02-18

    The first broadly applicable set of protocols for efficient Z-selective formation of macrocyclic disubstituted alkenes through catalytic ring-closing metathesis (RCM) is described. Cyclizations are performed with 1.2-7.5 mol% of a Mo- or W-based monoaryloxide pyrrolide (MAP) complex at 22 °C and proceed to complete conversion typically within two hours. Utility is demonstrated by synthesis of representative macrocyclic alkenes, such as natural products yuzu lactone (13-membered ring: 73% Z) epilachnene (15-membered ring: 91% Z), ambrettolide (17-membered ring: 91% Z), an advanced precursor to epothilones C and A (16-membered ring: up to 97% Z), and nakadomarin A (15-membered ring: up to 97% Z). We show that catalytic Z-selective cyclizations can be performed efficiently on gram-scale with complex molecule starting materials and catalysts that can be handled in air. We elucidate several critical principles of the catalytic protocol: 1) The complementary nature of the Mo catalysts, which deliver high activity but can be more prone towards engendering post-RCM stereoisomerization, versus W variants, which furnish lower activity but are less inclined to cause loss of kinetic Z selectivity. 2) Reaction time is critical to retaining kinetic Z selectivity not only with MAP species but with the widely used Mo bis(hexafluoro-tert-butoxide) complex as well. 3) Polycyclic structures can be accessed without significant isomerization at the existing Z alkenes within the molecule.

  20. 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+