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Sample records for diacylgycerol lactones dag-lactones

  1. Membrane anchoring of diacylglycerol lactones substituted with rigid hydrophobic acyl domains correlates with biological activities.

    PubMed

    Raifman, Or; Kolusheva, Sofiya; Comin, Maria J; Kedei, Noemi; Lewin, Nancy E; Blumberg, Peter M; Marquez, Victor E; Jelinek, Raz

    2010-01-01

    Synthetic diacylglycerol lactones (DAG lactones) are effective modulators of critical cellular signaling pathways downstream of the lipophilic second messenger diacylglycerol that activate a host of protein kinase C (PKC) isozymes as well as other non-kinase proteins that share with PKC similar C1 membrane-targeting domains. A fundamental determinant of the biological activity of these amphiphilic molecules is the nature of their interactions with cellular membranes. This study characterizes the membrane interactions and bilayer anchoring of a series of DAG lactones in which the hydrophobic moiety is a 'molecular rod', namely a rigid 4-[2-(R-phenyl)ethynyl]benzoate moiety in the acyl position. Use of assays employing chromatic biomimetic vesicles and biophysical techniques revealed that the mode of membrane anchoring of the DAG lactone derivatives was markedly affected by the presence of the hydrophobic diphenyl rod and by the size of the functional unit at the terminus of the rod. Two primary mechanisms of interaction were observed: surface binding of the DAG lactones at the lipid/water interface and deep insertion of the ligands into the alkyl core of the lipid bilayer. These membrane-insertion properties could explain the different patterns of the PKC translocation from the cytosol to membranes that is induced by the molecular-rod DAG lactones. This investigation emphasizes that the side residues of DAG lactones, rather than simply conferring hydrophobicity, profoundly influence membrane interactions, and thus may further contribute to the diversity of biological actions of these synthetic biomimetic ligands.

  2. Self-assembly and lipid interactions of diacylglycerol lactone derivatives studied at the air/water interface.

    PubMed

    Philosof-Mazor, Liron; Volinsky, Roman; Comin, Maria J; Lewin, Nancy E; Kedei, Noemi; Blumberg, Peter M; Marquez, Victor E; Jelinek, Raz

    2008-10-07

    Synthetic diacylglycerol lactones (DAG-lactones) have been shown to be effective modulators of critical cellular signaling pathways. The biological activity of these amphiphilic molecules depends in part upon their lipid interactions within the cellular plasma membrane. This study explores the thermodynamic and structural features of DAG-lactone derivatives and their lipid interactions at the air/water interface. Surface-pressure/area isotherms and Brewster angle microscopy revealed the significance of specific side-groups attached to the terminus of a very rigid 4-(2-phenylethynyl)benzoyl chain of the DAG-lactones, which affected both the self-assembly of the molecules and their interactions with phospholipids. The experimental data highlight the formation of different phases within mixed DAG-lactone/phospholipid monolayers and underscore the relationship between the two components in binary mixtures of different mole ratios. Importantly, the results suggest that DAG-lactones are predominantly incorporated within fluid phospholipid phases rather than in the condensed phases that form, for example, by cholesterol. Moreover, the size and charge of the phospholipid headgroups do not seem to affect DAG-lactone interactions with lipids.

  3. Lactones. 6. Microbial lactonization of gamma,delta-epoxy esters.

    PubMed

    Olejniczak, T; Gawroński, J; Wawrzeńczyk, C

    2001-06-01

    The ability of 19 microorganisms to perform the enantioselective lactonization of racemic gamma,delta-epoxy ester 3a and its 7-methyl homolog 3b was checked. It was found that Rhodotorula rubra preferentialy transformed both substrates to (-)-enantiomers of trans delta-hydroxy-gamma-lactones with ee 76% for 3a and 24% for 3b. The best efficiency (20-30%) and enantioselectivity (ee 60-100%) of formation of (-)-gamma-hydroxy-delta-lactones 6a and 6b was observed for lactonization by Botrytis cinerea and Fusarium semitectum, respectively.

  4. Lactones. 9. Synthesis of terpenoid lactones-active insect antifeedants.

    PubMed

    Paruch, E; Ciunik, Z; Nawrot, J; Wawrzeńczyk, C

    2000-10-01

    Starting from (+)- and (-)-perillyl alcohols, via Claisen rearrangement and iodolactonization, four enantiomeric pairs of gamma-lactones were obtained. The structures of compounds were established by both spectroscopic and crystallographic methods. The lactones were tested for antifeeding activity toward grain storage pests-the granary weevil beetle (Sitophilus granarius L.), the khapra beetle (Trogoderma granarium Ev.), and the confused flour beetle (Tribolium confusum Duv.). The results of the tests proved that two compounds, (1R,4R, 6R)-(-)-4-(1-methylethenyl)-9-oxabicyclo[4.3.0]nonan-8-one (8a) and its enantiomer (8b), are very active antifeedants against all of the above tested species. The lactone 8b is also active against the peach-potato aphid (Myzus persicae Sulz.). The activity depends on the absolute configurations of compound chiral centers. Additionally, the lactones 8a and 8b are characterized by interesting fragrances.

  5. Sesquiterpene lactones from Taraxacum obovatum.

    PubMed

    Michalska, Klaudia; Kisiel, Wanda

    2003-02-01

    Two new guaianolide glucosides, deacetylmatricarin 8-O-beta-glucopyranoside and 11beta-hydroxyleukodin 11-O-beta-glucopyranoside, were isolated from roots of Taraxacum obovatum, along with four known sesquiterpene lactones, deacetylmatricarin, sonchuside A, taraxinic acid beta-glucopyranosyl ester and its 11beta,13-dihydro derivative. Their structures were established by spectral methods.

  6. Carbohydrate-Based Lactones: Synthesis and Applications

    NASA Astrophysics Data System (ADS)

    Xavier, Nuno M.; Rauter, Amélia P.; Queneau, Yves

    The synthesis and uses of different kinds of carbohydrate-based lactones are described. This group of compounds includes aldonolactones, other related monocyclic lactones and bicyclic systems. The latter can arise from uronic acids, carboxymethyl ethers or glycosides, or from C-branched sugars.

  7. Role of the Chemokine MCP-1 in Sensitization of PKC-Mediated Apoptosis in Prostate Cancer Cells

    DTIC Science & Technology

    2009-02-01

    proteolytic cleavage of PKCδ. J. Biol. Chem. 275: 7574-7582 (2000). 4. Garcia -Bermejo, M.L., Leskow, F.C., Fujii, T., Wang, Q., Blumberg, P.M., Ohba...M., Kuroki, T., Han, K.C., Lee, J., Marquez , V.E., and Kazanietz, M.G. Diacylglycerol (DAG)- lactones, a new class of protein kinase C (PKC) agonists

  8. Role of the Chemokine MCP-1 in Sensitization of PKC-Medicated Apoptosis in Prostate Cancer Cells

    DTIC Science & Technology

    2008-02-01

    prostate cancer cells. Lack of proteolytic cleavage of PKCδ. J. Biol. Chem. 275: 7574-7582 (2000). 5. Garcia -Bermejo, M.L., Leskow, F.C., Fujii, T., Wang...Q., Blumberg, P.M., Ohba, M., Kuroki, T., 5 Han, K.C., Lee, J., Marquez , V.E., and Kazanietz, M.G. Diacylglycerol (DAG)-lactones, a new class of

  9. Sesquiterpenoids Lactones: Benefits to Plants and People

    PubMed Central

    Chadwick, Martin; Trewin, Harriet; Gawthrop, Frances; Wagstaff, Carol

    2013-01-01

    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. PMID:23783276

  10. 21 CFR 184.1318 - Glucono delta-lactone.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Glucono delta-lactone. 184.1318 Section 184.1318... GRAS § 184.1318 Glucono delta-lactone. (a) Glucono delta-lactone (C6H10O6, CAS Reg. No. 90-80-2), also called D-gluconic acid delta-lactone or D-glucono-1,5-lactone, is the cyclic 1,5-intramolecular ester...

  11. 21 CFR 184.1318 - Glucono delta-lactone.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Glucono delta-lactone. 184.1318 Section 184.1318... Listing of Specific Substances Affirmed as GRAS § 184.1318 Glucono delta-lactone. (a) Glucono delta-lactone (C6H10O6, CAS Reg. No. 90-80-2), also called D-gluconic acid delta-lactone or...

  12. 21 CFR 184.1318 - Glucono delta-lactone.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Glucono delta-lactone. 184.1318 Section 184.1318... Listing of Specific Substances Affirmed as GRAS § 184.1318 Glucono delta-lactone. (a) Glucono delta-lactone (C6H10O6, CAS Reg. No. 90-80-2), also called D-gluconic acid delta-lactone or...

  13. 21 CFR 184.1318 - Glucono delta-lactone.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glucono delta-lactone. 184.1318 Section 184.1318... Listing of Specific Substances Affirmed as GRAS § 184.1318 Glucono delta-lactone. (a) Glucono delta-lactone (C6H10O6, CAS Reg. No. 90-80-2), also called D-gluconic acid delta-lactone or...

  14. 21 CFR 184.1318 - Glucono delta-lactone.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Glucono delta-lactone. 184.1318 Section 184.1318... Listing of Specific Substances Affirmed as GRAS § 184.1318 Glucono delta-lactone. (a) Glucono delta-lactone (C6H10O6, CAS Reg. No. 90-80-2), also called D-gluconic acid delta-lactone or...

  15. Abietane lactones and iridoids from Goldfussia yunnanensis.

    PubMed

    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.

  16. Lactones: Part 11. Feeding-deterrent activity of some bi- and tricyclic terpenoid lactones.

    PubMed

    Paruch, E; Nawrot, J; Wawrzeńczyk, C

    2001-09-01

    The feeding-deterrent activities of thirteen synthetic terpenoid lactones, including isomeric bicyclic gamma-spirolactones with the limonene system and tricyclic gamma-lactones with the pinane system, were determined towards three storage pest insects: the adults of Sitophilus granarius, the adults and larvae of Tribolium confusum and the larvae of Trogoderma granarium. The configuration of chiral centres, as well as the presence of additional functional groups (double bond, iodine and hydroxy group) are important for antifeeding activity.

  17. New Sesquiterpene Lactones from Illicium floridanum

    PubMed

    Schmidt; Schmidt; Müller; Peters; Fronczek; Truesdale; Fischer

    1998-02-27

    In continuation of our phytochemical investigation of Illicium floridanum Ellis (American star anise, star bush), three new sesquiterpene lactones possessing the anisatin-type carbon skeleton (8,9-seco-prezizaane skeleton), 14-acetoxy-3-oxofloridanolide (1), 13-acetoxy-14-(n-butyryloxy)floridanolide (2), and 3beta-acetoxy-14-n-butyryloxy-10-deoxyfloridanolide (3), were isolated from fruits of this plant. Their structures were elucidated by 1D and 2D NMR measurements. The molecular structure of 1 was obtained by single crystal X-ray diffraction. The 11,3-delta-lactone structure of the compound previously described as debenzoyldunnianin in our previous communication, on grounds of NMR spectral evidence and X-ray crystallographic analysis is revised to a delta-lactone closed between C-11 and C-7 (compound 4). The neurotoxic sesquiterpene lactone anisatin (5) and its isomer 2alpha-hydroxyneoanisatin (3-deoxy-2alpha-hydroxyanisatin, 6) were also isolated and identified by spectroscopic means. The presence of the neurotoxin 5 in relatively high amounts in the fruits and leaves confirms and explains early reports on the toxicity of this plant.

  18. Chicory cultivars differ in sesquiterpene lactone composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chicory (Cichorium intybus L.) is a valuable forage species for small ruminants because it is nutritious and contains sesquiterpene lactones (SLs) that have anthelmintic activity. Three SLs, lactucin (lac), 8-deoxylactucin (dol), and lactucopicrin (lpic), occur in chicory leaves. Comprehensive dat...

  19. Triacetic acid lactone production from Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. Thermodynamic properties of sesquiterpene lactone grossheimin

    NASA Astrophysics Data System (ADS)

    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. Four new lactones from Botrytis cinerea.

    PubMed

    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.

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

    PubMed

    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.

  3. PKCα activation down-regulates ATM and radio-sensitizes androgen-sensitive human prostate cancer cells in vitro and in vivo

    PubMed Central

    Truman, Jean-Philip; Rotenberg, Susan A.; Kang, Ji-Hye; Lerman, Gabriel; Fuks, Zvi; Kolesnick, Richard; Marquez, Victor E.; Haimovitz-Friedman, Adriana

    2009-01-01

    We previously demonstrated that treatment of human androgen-responsive prostate cancer cell lines LNCaP and CWR22-Rv1 with 12-O-tetradecanoylphorbol 13-acetate (TPA), a known protein kinase C (PKC) activator, decreases ATM protein levels, thus de-repressing the enzyme ceramide synthase (CS) and promoting apoptosis as well as radio-sensitizing these cells.1 Here we show that PKCα mediates the TPA effect on ATM expression, since ATM suppression and apoptosis induced by either TPA or diacylglycerol-lactone (DAG-lactone), both inducing PKCα activation,2 are abrogated in LNCaP cells following transfection of a kinase-dead PKCα mutant (KD-PKCα). Similarly, KD-PKCα blocks the apoptotic response elicited by combination of TPA and radiation, whereas expression of constitutively active PKCα is sufficient to sensitize cells to radiation alone, without a need to pre-treat the cells with TPA. These findings identify CS activation as a downstream event of PKCα activity in LNCaP cells. Similar results were obtained in CWR22-Rv1 cells with DAG-lactone treatment. Using the LNCaP orthotopic prostate model it is shown that treatment with TPA or DAG-lactone induces significant reduction in tumor ATM levels coupled with tumor growth delay. Furthermore, while fractionated radiation alone produces significant tumor growth delay, pretreatment with TPA or DAG-lactone significantly potentiates tumor cure. These findings support a model in which activation of PKCα downregulates ATM, thus relieving CS repression by ATM and enhancing apoptosis via ceramide generation. This model may provide a basis for the design of new therapies in prostate cancer. PMID:19029835

  4. Characterization of a novel enzyme-Starmerella bombicola lactone esterase (SBLE)-responsible for sophorolipid lactonization.

    PubMed

    Ciesielska, Katarzyna; Roelants, Sophie L K W; Van Bogaert, Inge N A; De Waele, Stijn; Vandenberghe, Isabel; Groeneboer, Sara; Soetaert, Wim; Devreese, Bart

    2016-11-01

    We recently discovered a novel enzyme in the exoproteome of Starmerella bombicola, which is structurally related to Candida antarctica lipase A. A knockout strain for this enzyme does no longer produce lactonic sophorolipids, prompting us to believe that this protein is the missing S. bombicola lactone esterase (SBLE). SBLE catalyzes a rather unusual reaction, i.e., an intramolecular esterification (lactonization) of acidic sophorolipids in an aqueous environment, which raised questions about its activity and mode of action. Here, we report the heterologous production of this enzyme in Pichia pastoris and its purification in a two-step strategy. Purified recombinant SBLE (rSBLE) was used to perform HPLC and liquid chromatography mass spectrometry (LCMS)-based assays with different sophorolipid mixtures. We experimentally confirmed that SBLE is able to perform ring closure of acetylated acidic sophorolipids. This substrate was selected for rSBLE kinetic studies to estimate the apparent values of K m . We established that rSBLE displays optimal activity in the pH range of 3.5 to 6 and has an optimal temperature in the range of 20 to 50 °C. Additionally, we generated a rSBLE mutant through site-directed mutagenesis of Ser194 in the predicted active site pocket and show that this mutant is lacking the ability to lactonize sophorolipids. We therefore propose that SBLE operates via the common serine hydrolase mechanism in which the catalytic serine residue is assisted by a His/Asp pair.

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

    PubMed

    Boratyński, Filip; Smuga, Małgorzata; Wawrzeńczyk, Czesław

    2013-11-01

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

  6. Discovery of new lactones in sweet cream butter oil.

    PubMed

    Sarrazin, Elise; Frerot, Eric; Bagnoud, Alain; Aeberhardt, Kasia; Rubin, Mark

    2011-06-22

    Sweet cream butter oil was analyzed to identify new volatile compounds that may contribute to its flavor, with an emphasis on lactones. The volatile part of butter oil was obtained by using short-path distillation. As some previously unknown lactones were detected in this first extract, it was fractionated further. The fatty acids were removed, and the extract was fractionated by flash chromatography. Three lactonic fractions possessing a creamy, buttery, and fatty character were investigated in depth by gas chromatography (GC) and mass spectrometry (MS) (EI and CI) and high-resolution GC-time-of-flight MS. Many lactones were identified by their mass fragmentation and by comparison with reference materials synthesized during this work. Six γ-lactones, five δ-lactones, and one ε-lactone were identified for the first time in butter oil, seven of them for the first time in a natural product. The possible contribution of these new lactones to the aroma of butter oil is briefly discussed.

  7. Lactones 12. Enzymatic lactonization of gamma, delta-epoxy esters by the apple fruit and Jerusalem artichoke bulb.

    PubMed

    Olejniczak, Teresa; Mironowicz, Agnieszka; Wawrzeńczyk, Czesław

    2003-06-01

    The enzymatic lactonization of three acyclic gamma, delta-epoxy esters (ethyl 3,7-dimethyl-4,5-epoxyoctanoate, ethyl 3,7,7-trimethyl-4,5-epoxyoctanoate, and ethyl 3,3,7-trimethyl-4,5-epoxyoctanoate) by apple fruit (Malus silvestris) and Jerusalem artichoke bulb (Helianthus tuberosus L.) was investigated. The substrates were transformed into a mixture of isomeric delta-hydroxy-gamma-lactones and gamma-hydroxy-delta-lactones. The gamma-lactones (yields ranging from 45-70%) predominated over delta-lactones (yields ranging from 8-40%). The composition of the product mixture depended on the structure of substrate as well as the biocatalyst. The enzymatic system in these biocatalysts also exhibited diastereoselectivity and enantioselectivity.

  8. Lactones 41. Synthesis and microbial hydroxylation of unsaturated terpenoid lactones with p-menthane ring systems.

    PubMed

    Grudniewska, Aleksandra; Wawrzeńczyk, Czesław

    2013-03-01

    Racemic [(±)-4-isopropyl-1-methyl-7-oxa-cis-bicyclo[4.3.0]non-4-en-8-one] and optically active δ,ε-unsaturated lactones [(-)-(1R,6R)-4-isopropyl-1-methyl-7-oxabicyclo[4.3.0]non-4-en-8-one and (+)-(1S,6S)-4-isopropyl-1-methyl-7-oxabicyclo[4.3.0] non-4-en-8-one)] with the p-menthane system were obtained and their odoriferous properties were evaluated. Biotransformations of the racemic lactone with three fungal strains: Absidia cylindrospora AM336, Absidia glauca AM177 and Syncephalastrum racemosum AM105, were carried out. Microbial transformations afforded hydroxylactones with the hydroxy group in the allylic position.

  9. Lactones. 21. Synthesis and odoriferous properties of lactones with the p-menthane system.

    PubMed

    Dams, Iwona; Bialoniska, Agata; Ciunik, Zbigniew; Wawrzenczyk, Czesław

    2004-03-24

    Starting from (R)-(+)- and (S)-(-)-pulegone, enantiomeric pairs of esters and lactones with the p-menthane system were obtained. The Claisen rearrangement of allylic alcohols and iodolactonization of gamma,delta-unsaturated acids were the key steps of syntheses presented. The structures of compounds were determined by both spectroscopic and crystallographic methods. Some of the synthesized compounds are characterized by interesting odoriferous properties.

  10. Chemotypes in Achillea collina based on sesquiterpene lactone profile.

    PubMed

    Todorova, Milka; Trendafilova, Antoaneta; Mikhova, Bozhanka; Vitkova, Antonina; Duddeck, Helmut

    2007-07-01

    The lactone profile of six origins of Achillea collina growing in Bulgaria was studied and significant variability was observed. The reasons for the differences in the lactone composition are discussed. Twenty-five components in total were isolated and identified, while the presence of ten lactones was proved by intensive TLC analysis in comparison with reference compounds. The structures of the components 17, 20, 25-30 were established by spectroscopic methods. The structure of 7, a cyclization product of 6, was also discussed. The anti-inflammatory activity of some extracts, fractions and individual compounds was tested in vitro by determining the inhibitory effects on induced human neutrophils.

  11. Characteristic gamma-lactone odor production of the genus Pityrosporum.

    PubMed Central

    Labows, J N; McGinley, K J; Leyden, J J; Webster, G F

    1979-01-01

    Mass spectrometric-gas chromatographic analysis of culture headspaces revealed that members of the genous Pityrosporum produce volatile gamma-lactones during growth on lipid-containing media. Representative members of other yeast genera found on humans failed to produce these compounds. Addition of lecithin, oleic acids, triolein, or human sebum to the culture media stimulated gamma-lactone production by Pityrosporum species. All yeasts tested produced isopentanol and phenylethanol. Production of gamma-lactones may serve as a valuable characteristic in the identification of organisms of the genus Pityrosporum. PMID:533274

  12. Microbial metabolism of quorum-sensing molecules acyl-homoserine lactones, γ-heptalactone and other lactones.

    PubMed

    Safari, Maryam; Amache, Rana; Esmaeilishirazifard, Elham; Keshavarz, Tajalli

    2014-04-01

    The cell-to-cell communication of microorganisms is known to be via exertion of certain chemical compounds (signal molecules) and is referred to as quorum sensing (QS). QS phenomenon is widespread in microbial communities. Several Gram-positive and Gram-negative bacteria and fungi use lactone-containing compounds (e.g. acyl-homoserine lactones (AHLs), γ-heptalactone, butyrolactone-I) as signalling molecules. The ability of microorganisms to metabolise these compounds and the mechanisms they employ for this purpose are not clearly understood. Many studies, however, have focused on identifying AHL and other lactone-degrading enzymes produced by bacteria and fungi. Various strains that are able to utilise these signalling molecules as carbon and energy sources have also been isolated. In addition, several reports have provided evidence on the involvement of lactones and lactone-degrading enzymes in numerous biological functions. These studies, although focused on processes other than metabolism of lactone signalling molecules, still provide insights into further understanding of the mechanisms employed by various microorganisms to metabolise the QS compounds. In this review, we consider conceivable microbial strategies to metabolise AHL and other lactone-containing signalling molecules such as γ-heptalactones.

  13. Effect of α-tocopherol on lactone formation in marbled beef and changes in lactone volatility during storage.

    PubMed

    Watanabe, Akira; Imanari, Mai; Yonai, Miharu; Shiba, Nobuya

    2012-06-01

    Dynamic-headspace sampling with a standard-addition method was employed to quantitatively analyze aliphatic lactones in rendered fat from marbled beef and to evaluate the effect of the matrix on volatility. Further, the effects of different levels of the antioxidant α-tocopherol on lactone formation were examined. The slopes of the linear regression curves from the standard-addition method were significantly changed (P < 0.05 or 0.01) for all lactones after storage, with the exception of γ-octalactone, indicating the volatility of the longer-chain lactones were increased after storage. The concentrations of γ-lactones were increased after 7 d of storage at 2 °C (P < 0.01), and the α-tocopherol content in the meat affected the formation of γ-octalactone (P < 0.05) and γ-nonalactone (P < 0.01). The greatest increase was observed for γ-nonalactone in the lowest α-tocopherol (2.9 ppm) group: the concentration of 51.4 ppb was 11.7-fold higher than that before storage. Meanwhile, δ-tetradecalactone in the highest α-tocopherol (28.8 ppm) group showed the highest concentration for the lactones at 415.8 ppb, which was 2.6-fold higher than the concentration before storage. The effect of α-tocopherol was unclear for the δ-lactones. The results indicate that most of the γ-lactones are produced by oxidation during storage but that the other lactones are also generated by other processes as well.

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

    PubMed

    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.

  15. Sesquiterpene lactones from Achillea collina J. Becker ex Reichenb.

    PubMed

    Trendafilova, Antoaneta; Todorova, Milka; Mikhova, Bozhanka; Vitkova, Antonina; Duddeck, Helmut

    2006-04-01

    The flower heads of Achillea collina afforded 31 individual sesquiterpene lactones, among which nine guaianolides (1, 16, 20, 21, 23, 27-30), a germacranolide (18) and a dimeric guaianolide (31) were found to be new natural products. The lactones 2-4, 12, 14, 15, 17, 19 and 25 were isolated for the first time from the investigated species. Their structures were established by spectral methods.

  16. Kava lactones and the kava-kava controversy.

    PubMed

    Whitton, Peter A; Lau, Andrew; Salisbury, Alicia; Whitehouse, Julie; Evans, Christine S

    2003-10-01

    Kava-kava is a traditional beverage of the South Pacific islanders and has had centuries of use without major side effects. Standardised extracts of kava-kava produced in Europe have led to many serious health problems and even to death. The extraction process (aqueous vs. acetone in the two types of preparations) is responsible for the difference in toxicity as extraction of glutathione in addition to the kava lactones is important to provide protection against hepatotoxicity. The Michael reaction between glutathione and kava lactones, resulting in opening of the lactone ring, reduces the side effects of the kava kava extracts. This protective activity was demonstrated using Acanthamoebae castellanii in which 100% cell death occurred with 100 mg ml(-1) kava lactones alone, and 40% cell death with a mixture of 100 mg ml (-1)glutathione and 100 mg ml (-1) kava lactones. A comparison of kava lactone toxicity with other pharmaceutical products is discussed and recommendations made for safe usage of kava-kava products

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. C-Ring Cannabinoid Lactones: A Novel Cannabinergic Chemotype

    PubMed Central

    2014-01-01

    As a part of our controlled-deactivation ligand development project, we recently disclosed a series of (−)-Δ8-tetrahydrocannabinols (THCs) with a metabolically labile ester group at the 2′-position of the side chain. Now, we have replaced the C-ring in the classical THC structure with a hydrolyzable seven-membered lactone. One of the synthesized analogues binds with high affinity to the CB1 receptor (Ki = 4.6 nM) and exhibits much lower affinities for the mCB2 and the hCB2. Also, in vitro functional characterization found the compound to be an agonist at rCB1. Consistent with our rational design, the lead cannabinergic lactone identified here is susceptible to metabolic inactivation by plasma esterases, while the respective acid metabolite is inactive at CB receptors. These results are highlighted with molecular modeling of the two regiosomeric lactones. PMID:24900848

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

    PubMed

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

    2015-09-23

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

  20. Thermochemistry and kinetics of angelica and cognate lactones.

    PubMed

    Wurmel, Judith; Simmie, John M

    2014-06-12

    The enthalpies of formation, bond dissociation energies, ionization potentials, and kinetics of reaction with hydrogen atoms and methyl radicals have been systematically calculated for angelica lactone and a number of related furanones. The objective was to provide comprehensive thermodynamic and kinetic data of compounds that are projected to play a role as intermediates in the production of platform chemicals and biofuels.

  1. Triacetic acid lactone production in industrial Saccharomyces yeast strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triacetic acid lactone (TAL) is a potential platform chemical that can be produced in yeast. To evaluate the potential for industrial yeast strains to produce TAL, the g2ps1 gene encoding 2-pyrone synthase was transformed into thirteen industrial yeast strains of varied genetic background. TAL produ...

  2. Natural Sesquiterpene Lactones Induce Oxidative Stress in Leishmania mexicana

    PubMed Central

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

    2013-01-01

    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 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. PMID:23861697

  3. Asymmetric gold-catalyzed lactonizations in water at room temperature.

    PubMed

    Handa, Sachin; Lippincott, Daniel J; Aue, Donald H; Lipshutz, Bruce H

    2014-09-26

    Asymmetric gold-catalyzed hydrocarboxylations are reported that show broad substrate scope. The hydrophobic effect associated with in situ-formed aqueous nanomicelles gives good to excellent ee's of product lactones. In-flask product isolation, along with the recycling of the catalyst and the reaction medium, are combined to arrive at an especially environmentally friendly process.

  4. Lactones in 193 nm resists: What do they do?

    NASA Astrophysics Data System (ADS)

    Ito, Hiroshi; Truong, Hoa D.; Brock, Phil J.

    2008-03-01

    Lactones are almost ubiquitously employed in 193 nm resists to increase the polarity of hydrophobic alicyclic polymers. What else do lactones do in 193 nm resists? We studied the behavior of methacrylate (MA) resists consisting of different protecting groups, hexafluoroalcohols, and norbornane lactone methacrylate (NLM, 2-oxo-3-oxatricyclo[4.2.1.04,8]nonan-5-yl methacrylate). When the protecting group is large [ethylcyclooctyl (ECO) and methyladamantyl (MAd)], thinning of the resist film that occurs in highly exposed areas upon postexposure bake (PEB) is significantly smaller than what is expected from the polymer composition. When the concentration of isopropylhexafluoroalcohol methacrylate (iPrHFAMA) is increased in the ECOMA-NLM polymer, the thinning increases and reaches 100% of theory and the ECOMA-norbornenehexafluoroalcohol methacrylate (NBHFAMA) resist loses quantitative thickness in highly-exposed areas upon PEB at 90 °C. This indicates that small lactones which are more basic than esters can trap deprotection fragments especially when the protecting group is large. Such entrapment was detected by IR spectroscopy and also observed at temperatures as high as 200 °C in thermogravimetric analysis (TGA). Incorporation of lactone appears to decrease the bake temperature sensitivity and the sensitivity of the resist perhaps due to trapping of photochemically generated acids by basic lactone. The lactone ring can be hydrolyzed during aqueous base development but does not seem to affect the dissolution rate, indicating that hydrolysis occurs in aqueous base solution after dissolution. Poly(methacrylic acid-NLM) dissolves as fast as poly(methacrylic acid) in 0.26 N tetramethylammonium hydroxide (TMAH) aqueous solution. While exposed P(ECOMA 47-NLM 53) resist dissolves in 0.26 N developer at about the same rate as authentically prepared poly(methacrylic acid 47-NLM 53), the dissolution rate of highly-exposed P(MAdMA 44-NLM 56) resist is much slower, indicating

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

    PubMed

    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.

  6. Thiourea-Catalyzed Aminolysis of N-acyl Homoserine Lactones

    DTIC Science & Technology

    2013-01-01

    of N-acyl homoserine lactones (AHLs), molecules integral to bacterial quorum sensing . The catalysts afford rate enhancement of up to 10 times the...SUBJECT TERMS quorum sensing Michael A. Bertucci, Stephen J. Lee, Michel R. Gagné University of North Carolina - Chapel Hill Office of Sponsored... quorum sensing . The catalysts afford rate enhancement of up to 10 times the control in CD3CN. Mild catalysis in other polar aprotic solvents is

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

    PubMed Central

    Callaghan, Breedge; Lydon, Helen; Roelants, Sophie L. K. W.; Van Bogaert, Inge N. A.; Marchant, Roger; Banat, Ibrahim M.; Mitchell, Christopher A.

    2016-01-01

    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. PMID:27271048

  8. Molluscicidal sesquiterpene lactones from species of the tribe Vernonieae (Compositae).

    PubMed

    Borkosky, Susana; Ponce de León, Susana; Juárez, Gabriela; Sierra, Manuel González; Bardón, Alicia

    2009-04-01

    Schistosomiasis is caused by parasitic flatworms of the genus Schistosoma, and some snails, particularly of the genus Biomphalaria (Planorbidae), are directly implicated in the transmission of the disease. Continuing with our investigations of bioactive plant constituents, we evaluated and report in the present article, the molluscicidal effects of 16 sesquiterpene lactones, as well as the commercial reagents tetrahydrofuran, furfural, and furfuryl alcohol, on an adult population of B. peregrina. The natural sesquiterpene lactones tested are characteristic constituents of species of the tribe Vernonieae, family Asteraceae. Compounds 1-3 and 7 came from a Bolivian collection of Vernonanthura pinguis, compounds 4 and 5 from an Argentine collection of Cyrtocymura cincta var. cincta, 6 was obtained from a Bolivian collection of Eirmocephala megaphylla, 8-14 from an Argentine collection of Centratherum punctatum ssp. punctatum, and compounds 15 and 16 were obtained by chemical derivatization from 5 and 14, respectively. Ten of the sesquiterpene lactones displayed moderate molluscicidal activity (LD50<100 microg/ml). Commercial reagents were inactive.

  9. Kinetics of lactone hydrolysis in antitumor drugs of camptothecin series as studied by fluorescence spectroscopy.

    PubMed

    Chourpa, I; Millot, J M; Sockalingum, G D; Riou, J F; Manfait, M

    1998-03-02

    Potent antitumor activity exhibited by 20-S-camptothecin (CPT) and numerous derivatives is known to be lost upon opening of the alpha-hydroxy-lactone ring of these drugs, hydrolyzable at neutral and basic pH. To quantify in 'real time' the lactone hydrolysis reaction in CPTs under physiological conditions, we have applied a non-perturbing approach by fluorescence spectroscopy. CPT and a set of its derivatives (21-lactam-S-CPT, 10,11-(methylenedioxy)-CPT, CPT-11, SN-38, topotecan, tricyclic ketone-CPT) with antitumor activity varying from negligible to 10 times that of CPT have been studied. Prior to the kinetic measurements, the effects of substitutions, pH, polarity of molecular environment, lactone ring opening (lactone-carboxylate transition) have been investigated in terms of the UV-visible absorption and fluorescence emission spectra of CPTs. Then the determined parameters of the fluorescence emission spectra corresponding to the respective lactone and carboxylate forms have been used to estimate the residual lactone percentage as a function of time. The reproducibility of the obtained data demonstrates that the spectroscopic approach provides a satisfactory precision for this kind of measurements. For CPT at pH 7.3, the lactone half-life was 29.4 +/- 1.7 min and the lactone percentage at equilibrium was 20.9 +/- 0.3%. Within a series of derivatives with substitutions at quinoline rings, the lactone half-life varied from 29 to 32 min and the equilibrium lactone content varied from 15% to 23%. For each compound, even slight increase of pH from 7.1 to 7.3 or from 7.3 to 7.6 logically leads to a remarkable decrease of both lactone half-life and equilibrium lactone percentage.

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

    PubMed

    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.

  11. Phosphorylation of α-Tubulin by Protein Kinase C Stimulates Microtubule Dynamics in Human Breast Cells

    PubMed Central

    De, Shatarupa; Tsimounis, Areti; Chen, Xiangyu; Rotenberg, Susan A.

    2014-01-01

    Protein kinase C (PKC) engenders motility through phosphorylation of α-tubulin at Ser-165 in non-transformed MCF-10A cells. Live cell imaging explored the impact of PKC-mediated phosphorylation on microtubule (MT) dynamics. MTs fluorescently labeled with GFP-α-tubulin were treated with diacylglycerol (DAG)-lactone (a membrane-permeable PKC activator), or co-transfected with a pseudo-phosphorylated S165D-α6-tubulin mutant. Each condition increased the dynamicity of MTs by stimulating the rate and duration of the growth phase and decreasing the frequency of catastrophe. In MDA-MB-231 metastatic breast cells where the intrinsic PKC activity is high, these MT growth parameters were also high but could be suppressed by expression of phosphorylation-resistant S165N-α6-tubulin or by treatment with a pan-PKC inhibitor (bis-indoleylmaleimide). Sub-cellular fractionation and immunofluorescence of MCF-10A cells showed that phosphorylation (via DAG-lactone) or pseudo-phosphorylation of α6-tubulin increased its partitioning into MTs as compared to controls, and produced longer, more stable MTs. Following expression of the plus-end binding protein GFP-EB1, DAG-lactone accelerated the formation and increased the number of nascent MTs. Expression of S165D-α6-tubulin promoted Rac1 activation and Rac1-dependent cell motility. These findings call attention to PKC-mediated phosphorylation of α-tubulin as a novel mechanism for controlling the dynamics of MTs that result in cell movement. PMID:24574051

  12. beta2-chimaerin is a novel target for diacylglycerol: binding properties and changes in subcellular localization mediated by ligand binding to its C1 domain.

    PubMed

    Caloca, M J; Garcia-Bermejo, M L; Blumberg, P M; Lewin, N E; Kremmer, E; Mischak, H; Wang, S; Nacro, K; Bienfait, B; Marquez, V E; Kazanietz, M G

    1999-10-12

    The members of the chimaerin family of Rac-GTPase-activating proteins possess a single C1 domain with high homology to those present in protein kinase C (PKC) isozymes. This domain in PKCs is involved in phorbol ester and diacylglycerol (DAG) binding. We previously have demonstrated that one of the chimaerin isoforms, beta2-chimaerin, binds phorbol esters with high affinity. In this study we analyzed the properties of beta2-chimaerin as a DAG receptor by using a series of conformationally constrained cyclic DAG analogues (DAG lactones) as probes. We identified analogs that bind to beta2-chimaerin with more than 100-fold higher affinity than 1-oleoyl-2-acetylglycerol. The potencies of these analogs approach those of the potent phorbol ester tumor promoters. The different DAG lactones show some selectivity for this novel receptor compared with PKCalpha. Cellular studies revealed that these DAG analogs induce translocation of beta2-chimaerin from cytosolic (soluble) to particulate fractions. Using green fluorescent protein-fusion proteins for beta2-chimaerin we determined that this novel receptor translocates to the perinuclear region after treatment with DAG lactones. Binding and translocation were prevented by mutation of the conserved Cys-246 in the C1 domain. The structural homology between the C1 domain of beta2-chimaerin and the C1b domain of PKCdelta also was confirmed by modeling analysis. Our results demonstrate that beta2-chimaerin is a high affinity receptor for DAG through binding to its C1 domain and supports the emerging concept that multiple pathways transduce signaling through DAG and the phorbol esters.

  13. Macrocyclic lactone anthelmintics: spectrum of activity and mechanism of action.

    PubMed

    Geary, Timothy G; Moreno, Yovany

    2012-05-01

    Macrocyclic lactones (MLs), exemplified by the prototype of the class, ivermectin (IVM), are mainstays of programs for the control of nematode and arthropod parasites and pests. Since their introduction 30 years ago, research has revealed that they act on a family of ligand-gated chloride channels gated by glutamate, which is largely restricted to animals in the phyla Nematoda and Arthropoda. Studies on IVM in model organisms have contributed greatly to our understanding of ML pharmacology, but our understanding of the basis for differences among species and among MLs in potency and spectrum remains far from complete.

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

    PubMed

    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.

  15. Sesquiterpene lactone composition of wild and cultivated sunflowers and biological activity against an insect pest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sesquiterpene lactones in sunflowers, Helianthus spp., are important to interactions with pathogens, weeds and insects. Across a broad range of H. annuus, differences in composition of sesquiterpene lactones extracted from florets were found between wild and cultivated sunflowers, but also between d...

  16. A new sesquiterpene lactone with sulfonic acid group from Saussurea lappa.

    PubMed

    Yin, Hong-Quan; Hua, Hui-Ming; Fu, Hong-Wei; Qi, Xiu-Lan; Li, Wen; Sha, Yi; Pei, Yue-Hu

    2007-01-01

    A new sesquiterpene lactone with an unusual sulfonic acid group, 13-sulfo-dihydrodehydrocostus lactone (1), was isolated from the roots of Saussurea lappa C. (Compositae), together with a known lignan (2). The structure of 1 was characterized on the basis of spectral evidence including 2DNMR studies. Compound 2 was obtained from this plant for the first time.

  17. A novel plasmid for detection of N-acyl homoserine lactones.

    PubMed

    Ling, Elizabeth A; Ellison, Matthew L; Pesci, Everett C

    2009-07-01

    Many bacteria utilize acyl-homoserine lactones as cell to cell signals that can regulate the expression of numerous genes. Structural differences in acyl-homoserine lactones produced by different bacteria, such as acyl side chain length and the presence or absence of an oxy group, make many of the commonly used detection bioassays impractical for broad range detection. Here we present a simple, broad range acyl-homoserine lactone detection bioassay that can be used to detect a wide range of these chemical signals. A plasmid (pEAL01) was constructed and transformed into Pseudomonas aeruginosa strain QSC105 to allow for detection of a broad range of acyl-homoserine lactones through induction of a lasB'-lacZ transcriptional fusion. Monitoring beta-galactosidase activity from this bioassay showed that P. aeruginosa strain QSC105 (pEAL01) could detect the presence of eight acyl-homoserine lactones tested at physiological concentrations. This novel strain could also detect acyl-homoserine lactones from the extracts of four different bacteria that produce different acyl-homoserine lactones signals. These data indicate that strain QSC105 (pEAL01) can be used to detect a wide variety of acyl-homoserine lactones by a simple beta-galactosidase assay and this bioassay could be a useful and inexpensive tool to quickly identify the presence of these signal molecules.

  18. Piperitone-derived saturated lactones: synthesis and aphid behavior-modifying activity.

    PubMed

    Grudniewska, Aleksandra; Dancewicz, Katarzyna; Białońska, Agata; Wawrzeńczyk, Czesław; Gabryś, Beata

    2013-04-10

    Two racemic and two enantiomeric pairs of new saturated lactones with the p-menthane system were obtained. The lactones were synthesized from racemic and enantiomerically enriched cis- and trans-piperitols, which were obtained from piperitone. The structures of the compounds were confirmed by spectroscopic data. The antifeedant activity of piperitone to Myzus persicae was studied, and the biological consequences of structural modifications of piperitone, that is, lactonization and chiral center configuration, were examined as well. The behavioral responses of M. persicae to piperitone and piperitone-derived saturated lactones were investigated to reveal the biological background of their deterrent activity. Piperitone appeared rather neutral or weakly deterrent to aphids. The introduction of a lactone moiety into a piperitone molecule dramatically changed its biological activity. All piperitone-derived lactones evoked negative aphid responses. However, the deterrent activity of individual compounds varied in potency, the time of expression, and the duration of the effect, depending on the spatial structure of the lactone. Lactones (1R,3S,6R)-3-isopropyl-6-methyl-9-oxabicyclo[4.3.0]nonan-8-one and trans-3-isopropyl-6-methyl-9-oxabicyclo[4.3.0]nonan-8-one showed the broadest ranges and the highest potencies and durabilities of deterrent activity to M. persicae: they acted immediately after application, caused a cessation of probing before aphids reached phloem elements, and decreased the quality of phloem sap.

  19. 4-Hydroxy-7-oxo-5-heptenoic Acid Lactone Induces Angiogenesis through Several Different Molecular Pathways.

    PubMed

    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

  20. Cytotoxic sesquiterpene lactones from the root of Saussurea lappa.

    PubMed

    Sun, Chang-Ming; Syu, Wan-Jr; Don, Ming-Jaw; Lu, Jang-Jih; Lee, Gum-Hee

    2003-09-01

    Bioassay-directed fractionation of Saussurea lappa led to the isolation of a novel lappadilactone (1) and seven sesquiterpene lactones (2-8) as cytotoxic principles against selected human cancer cell lines. Lappadilactone (1), dehydrocostuslactone (2), and costunolide (5) exhibited the most potent cytotoxicity with CD50 values in the range 1.6-3.5 microg/mL in dose- and time-dependent manners. The cytotoxicities were not specific and showed similar activities against HepG2, OVCAR-3 and HeLa cell lines. The structure-activity relationship showed that the alpha-methylene-gamma-lactone moiety is necessary for cytotoxicity, and activity is reduced with the presence of a hydroxyl group. In addition, seven noncytotoxic compounds (9-15) were also isolated, including two novel sesquiterpenes, a guaianolide-type with a C17 skeleton, lappalone (13), and 1beta,6alpha-dihydroxycostic acid ethyl ester (14). The structures of the new compounds were elucidated from spectroscopic and/or X-ray data interpretations. Some representative compounds were also tested for antibacterial activity; however, only marginal activities were observed. Therefore, compounds 1-8 are potential cytotoxic agents but without significant antibacterial effect.

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

    PubMed

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

    2014-07-18

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

  2. Copolymerization of carbon dioxide and butadiene via a lactone intermediate.

    PubMed

    Nakano, Ryo; Ito, Shingo; Nozaki, Kyoko

    2014-04-01

    Although carbon dioxide has attracted broad interest as a renewable carbon feedstock, its use as a monomer in copolymerization with olefins has long been an elusive endeavour. A major obstacle for this process is that the propagation step involving carbon dioxide is endothermic; typically, attempted reactions between carbon dioxide and an olefin preferentially yield olefin homopolymerization. Here we report a strategy to circumvent the thermodynamic and kinetic barriers for copolymerizations of carbon dioxide and olefins by using a metastable lactone intermediate, 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one, which is formed by the palladium-catalysed condensation of carbon dioxide and 1,3-butadiene. Subsequent free-radical polymerization of the lactone intermediate afforded polymers of high molecular weight with a carbon dioxide content of 33 mol% (29 wt%). Furthermore, the protocol was applied successfully to a one-pot copolymerization of carbon dioxide and 1,3-butadiene, and one-pot terpolymerizations of carbon dioxide, butadiene and another 1,3-diene. This copolymerization technique provides access to a new class of polymeric materials made from carbon dioxide.

  3. Copolymerization of carbon dioxide and butadiene via a lactone intermediate

    NASA Astrophysics Data System (ADS)

    Nakano, Ryo; Ito, Shingo; Nozaki, Kyoko

    2014-04-01

    Although carbon dioxide has attracted broad interest as a renewable carbon feedstock, its use as a monomer in copolymerization with olefins has long been an elusive endeavour. A major obstacle for this process is that the propagation step involving carbon dioxide is endothermic; typically, attempted reactions between carbon dioxide and an olefin preferentially yield olefin homopolymerization. Here we report a strategy to circumvent the thermodynamic and kinetic barriers for copolymerizations of carbon dioxide and olefins by using a metastable lactone intermediate, 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one, which is formed by the palladium-catalysed condensation of carbon dioxide and 1,3-butadiene. Subsequent free-radical polymerization of the lactone intermediate afforded polymers of high molecular weight with a carbon dioxide content of 33 mol% (29 wt%). Furthermore, the protocol was applied successfully to a one-pot copolymerization of carbon dioxide and 1,3-butadiene, and one-pot terpolymerizations of carbon dioxide, butadiene and another 1,3-diene. This copolymerization technique provides access to a new class of polymeric materials made from carbon dioxide.

  4. The thermodynamic properties of alkylated γ-lactones

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Remodeling Natural Products: Chemistry and Serine Hydrolase Activity of a Rocaglate-Derived β-Lactone

    PubMed Central

    2015-01-01

    Flavaglines are a class of natural products with potent insecticidal and anticancer activities. β-Lactones are a privileged structural motif found in both therapeutic agents and chemical probes. Herein, we report the synthesis, unexpected light-driven di-epimerization, and activity-based protein profiling of a novel rocaglate-derived β-lactone. In addition to in vitro inhibition of the serine hydrolases ABHD10 and ACOT1/2, the most potent β-lactone enantiomer was also found to inhibit these enzymes, as well as the serine peptidases CTSA and SCPEP1, in PC3 cells. PMID:24447064

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

    PubMed

    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.

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

    PubMed Central

    Zan, Jindong; Liu, Yue; Fuqua, Clay; Hill, Russell T.

    2014-01-01

    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. PMID:24402124

  10. A Comparative Analysis of Acyl-Homoserine Lactone Synthase Assays.

    PubMed

    Shin, Daniel; Frane, Nicole D; Brecht, Ryan M; Keeler, Jesse; Nagarajan, Rajesh

    2015-12-01

    Quorum sensing is cell-to-cell communication that allows bacteria to coordinate attacks on their hosts by inducing virulent gene expression, biofilm production, and other cellular functions, including antibiotic resistance. AHL synthase enzymes synthesize N-acyl-l-homoserine lactones, commonly referred to as autoinducers, to facilitate quorum sensing in Gram-negative bacteria. Studying the synthases, however, has proven to be a difficult road. Two assays, including a radiolabeled assay and a colorimetric (DCPIP) assay are well-documented in literature to study AHL synthases. In this paper, we describe additional methods that include an HPLC-based, C-S bond cleavage and coupled assays to investigate this class of enzymes. In addition, we compare and contrast each assay for both acyl-CoA- and acyl-ACP-utilizing synthases. The expanded toolkit described in this study should facilitate mechanistic studies on quorum sensing signal synthases and expedite discovery of antivirulent compounds.

  11. Sesquiterpene Lactone Composition of Wild and Cultivated Sunflowers and Biological Activity against an Insect Pest.

    PubMed

    Prasifka, Jarrad R; Spring, Otmar; Conrad, Jürgen; Cook, Leonard W; Palmquist, Debra E; Foley, Michael E

    2015-04-29

    Sesquiterpene lactones in sunflowers, Helianthus spp., are important to interactions with pathogens, weeds, and insects. Across a broad range of Helianthus annuus, differences in composition of sesquiterpene lactones extracted from disc florets were found between wild and cultivated sunflowers and also between distinct groups of inbreds used to produce sunflower hybrids. Discriminant function analysis showed the presence and relative abundance of argophyllone B, niveusin B, and 15-hydroxy-3-dehydrodesoxyfruticin were usually (75%) effective at classifying wild sunflowers, cultivated inbreds, and hybrids. Argophyllone B reduced the larval mass of the sunflower moth, Homeosoma electellum, by >30%, but only at a dose greater than that found in florets. Low doses of mixed extracts from cultivated florets produced a similar (≈40%) reduction in larval mass, suggesting combinations of sesquiterpene lactones act additively. Although the results support a role for sesquiterpene lactones in herbivore defense of cultivated sunflowers, additional information is needed to use these compounds purposefully in breeding.

  12. Dehydrocostus lactone prevents mitochondrial dysfunction in osteoblastic MC3T3-E1 cells.

    PubMed

    Choi, Eun Mi

    2011-08-16

    The dried root of Saussurea lappa Clarke (Compositae) has been used as a traditional medicine. Dehydrocostus lactone is one of the main bioactive constituents of this medicinal plant. In the present study, the protective effect of dehydrocostus lactone against antimycin A (an inhibitor of mitochondrial complex III)-induced cytotoxicity was investigated in osteoblastic MC3T3-E1 cells. Pre-treatment with dehydrocostus lactone prior to antimycin A exposure significantly prevented mitochondrial membrane potential dissipation, complex IV inactivation, ATP loss, cytochrome c release, intracellular calcium elevation and potassium loss, and reactive oxygen species production induced by antimycin A. These results suggest that dehydrocostus lactone protects osteoblastic MC3T3-E1 cells from antimycin A-induced cell damage through the improved mitochondrial function.

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

    PubMed

    Tabata, Keiichi; Nishimura, Yuki; Takeda, Taiji; Kurita, Masahiro; Uchiyama, Taketo; Suzuki, Takashi

    2015-04-01

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

  14. Synthesis and biological evaluation of α,β-unsaturated lactones as potent immunosuppressive agents.

    PubMed

    Lee, Sun-Mi; Lee, Won-Gil; Kim, Young-Chul; Kim, Yong-Chul; Ko, Hyojin

    2011-10-01

    Compounds having α,β-unsaturated lactones display a variety of biological activities. Many research groups have tested both natural and unnatural α,β-unsaturated lactones for as-yet undiscovered biological properties. We synthesized α,β-unsaturated lactones with various substituents at the δ-position and studied their immunosuppressive effects, that is, the inhibition of Interleukin-2 (IL-2) production. Among the compounds synthesized, the benzofuran-substituted α,β-unsaturated lactone 4h showed the best inhibitory activity toward IL-2 production in Jurkat e6-1 T lymphocytes (IC(50)=66.9 nM) without cytotoxicity at 10 μM. The results indicated that 4h may be useful as a potent immunosuppressive agent, as well as in IL-2-related studies.

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

    PubMed Central

    Yin, Wai-Fong; Purmal, Kathiravan; Chin, Shenyang; Chan, Xin-Yue; Chan, Kok-Gan

    2012-01-01

    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. PMID:23202161

  16. Statin induced myotoxicity: the lactone forms are more potent than the acid forms in human skeletal muscle cells in vitro.

    PubMed

    Skottheim, Ine Blankenberg; Gedde-Dahl, Ane; Hejazifar, Solmaz; Hoel, Kjersti; Asberg, Anders

    2008-04-23

    Statins exist in both acid and lactone forms in vivo. High plasma levels of the lactone forms have been observed in patients with statin induced myopathy. In the present study, the hypothesis that lactone forms have a higher potency of inducing myotoxicity as compared to acid forms was investigated. Primary human skeletal muscle cells were incubated with increasing concentrations of lactone and acid forms of atorvastatin, fluvastatin, pravastatin and simvastatin. Following incubation, living myotubes were quantified by fluorescence staining. Atorvastatin lactone showed a 14-fold, fluvastatin lactone a 26-fold, pravastatin lactone a 23-fold, and simvastatin lactone a 37-fold higher potency to induce myotoxicity compared to their corresponding acid forms. Thus, for the four different statins the present study shows a significantly higher potency of the lactone forms, than the respective acid forms, to induce myotoxicity in human skeletal muscle cells in vitro. These results clearly indicate the need to differentiate between acid and lactone forms in future investigation of statin myotoxicity.

  17. Sesquiterpene lactone stereochemistry influences herbivore resistance and plant fitness in the field

    PubMed Central

    Ahern, Jeffrey R.; Whitney, Kenneth D.

    2014-01-01

    Background and Aims Stereochemical variation is widely known to influence the bioactivity of compounds in the context of pharmacology and pesticide science, but our understanding of its importance in mediating plant–herbivore interactions is limited, particularly in field settings. Similarly, sesquiterpene lactones are a broadly distributed class of putative defensive compounds, but little is known about their activities in the field. Methods Natural variation in sesquiterpene lactones of the common cocklebur, Xanthium strumarium (Asteraceae), was used in conjunction with a series of common garden experiments to examine relationships between stereochemical variation, herbivore damage and plant fitness. Key Results The stereochemistry of sesquiterpene lactone ring junctions helped to explain variation in plant herbivore resistance. Plants producing cis-fused sesquiterpene lactones experienced significantly higher damage than plants producing trans-fused sesquiterpene lactones. Experiments manipulating herbivore damage above and below ambient levels found that herbivore damage was negatively correlated with plant fitness. This pattern translated into significant fitness differences between chemotypes under ambient levels of herbivore attack, but not when attack was experimentally reduced via pesticide. Conclusions To our knowledge, this work represents only the second study to examine sesquiterpene lactones as defensive compounds in the field, the first to document herbivore-mediated natural selection on sesquiterpene lactone variation and the first to investigate the ecological significance of the stereochemistry of the lactone ring junction. The results indicate that subtle differences in stereochemistry may be a major determinant of the protective role of secondary metabolites and thus of plant fitness. As stereochemical variation is widespread in many groups of secondary metabolites, these findings suggest the possibility of dynamic evolutionary histories

  18. Influence of cultivation site on sesquiterpene lactone composition of forage chicory (Cichorium intybus L.).

    PubMed

    Foster, Joyce G; Clapham, William M; Belesky, David P; Labreveux, Maria; Hall, Marvin H; Sanderson, Matt A

    2006-03-08

    The forage potential of chicory (Cichorium intybus L.) has not been realized in southern West Virginia (WV) because ruminants are reluctant to consume the herbage. Chicory contains bitter sesquiterpene lactones that can adversely impact palatability. This study was undertaken to determine whether sesquiterpene lactone concentrations in chicory grown in southern WV differ from those in chicory grown in central Pennsylvania (PA) where chicory is grazed readily. Herbage was collected in 1997 and 1998 from cultivars Grasslands Puna (Puna), INIA le Lacerta (Lacerta), and Forage Feast established at research sites near State College, PA, and Beckley, WV. The total concentration of sesquiterpene lactones in WV-grown cultivars was 0.58% (dry matter basis) in Puna, 0.59% in Lacerta, and 0.79% in Forage Feast in 1997 and ranged from 1.03 (Lacerta) to 1.52% (Forage Feast) in 1998. In PA-grown cultivars, sesquiterpene lactones represented 0.16 (Puna), 0.18 (Lacerta), and 0.27% (Forage Feast) of the forage dry matter in 1997 and ranged from 0.32 (Lacerta) to 0.55% (Forage Feast) in 1998. Concentrations of lactucin, lactucopicrin, and total sesquiterpene lactones in Forage Feast exceeded those in the other cultivars grown at the same site. The lowest concentrations of lactucopicrin and total sesquiterpene lactones observed among WV-grown cultivars were higher (2-fold or more) than the highest concentrations present in cultivars grown the same year in PA. Mineral analyses of soils from the two cultivation sites indicate that P availability may influence sesquiterpene lactone composition of chicory herbage. Results provide a foundation for future studies of environmental effects on sesquiterpene lactone composition and palatability of chicory herbage.

  19. Germa-gamma-lactones as novel inhibitors of bacterial urease activity.

    PubMed

    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.

  20. Labrenzia sp. BM1: A Quorum Quenching Bacterium That Degrades N-acyl Homoserine Lactones via Lactonase Activity

    PubMed Central

    Ghani, Norshazliza Ab; Norizan, Siti Nur Maisarah; Chan, Xin Yue; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    We report the degradation of quorum sensing N-acylhomoserine lactone molecules by a bacterium isolated from a Malaysian marine water sample. MALDI-TOF and phylogenetic analysis indicated this isolate BM1 clustered closely to Labrenzia sp. The quorum quenching activity of this isolate was confirmed by using a series of bioassays and rapid resolution liquid chromatography analysis. Labrenzia sp. degraded a wide range of N-acylhomoserine lactones namely N-(3-hexanoyl)-l-homoserine lactone (C6-HSL), N-(3-oxohexanoyl)-l-homoserine lactone (3-oxo-C6-HSL) and N-(3-hydroxyhexanoyl)-l-homoserine lactone (3-hydroxy-C6-HSL). Re-lactonisation bioassays confirmed Labrenzia sp. BM1 degraded these signalling molecules efficiently via lactonase activity. To the best of our knowledge, this is the first documentation of a Labrenzia sp. capable of degrading N-acylhomoserine lactones and confirmation of its lactonase-based mechanism of action. PMID:24995373

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

    PubMed

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

    2017-01-12

    The structures of acyl homoserine lactone (AHL) compounds and their quantification was accomplished using an integrated liquid chromatography-mass spectrometry approach. The precursor and product ions, along with retention times of peaks, were searched against an in-house database of AHLs and structures confirmed by accurate mass and by comparison with authentic AHL standards. The two compounds, N-(3-oxodecanoyl)-L-homoserine lactone and N-(3-oxododecanoyl)-L-homoserine lactone were characterised and quantified in Salinispora sp. cultures.

  2. Lactonization and protonation of gluconic acid: a thermodynamicand kinetic study by potentiometry, nmr and esi-ms

    SciTech Connect

    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.

  3. Short communication: Macrocyclic lactone residues in butter from Brazilian markets.

    PubMed

    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.

  4. Dermatobia hominis: Potencial risk of resistance to macrocyclic lactones.

    PubMed

    das Neves, José Henrique; Carvalho, Nadino; Amarante, Alessandro F T

    2015-09-15

    Dermatobia hominis is an ectoparasite that infests various species of mammals, including cattle, impairing the quality of cowhides and leather. After observing natural infestation with D. hominis larvae in cattle on two farms in the state of São Paulo, Brazil, we evaluated the efficacy of two macrocyclic lactones, ivermectin and moxidectin, against this parasite. The drugs were administered to 10 animals in each group, following the manufacturer's instructions. The groups were: Group 1-treated with ivermectin (0.2mg/kg of body weight (BW)); Group 2-treated with moxidectin (0.2mg/kg BW); and Group 3-control (untreated). On the farm in Pardinho, a total of 12 and 16 live larvae were found in 6 and in 8 animals 10 days after the treatment with ivermectin and moxidectin, respectively, while in the control group 4 bovines had a total of 7 live larvae. On the farm in Anhembi, 2, 4 and 6 live larvae were extracted from ivermectin, moxidectin and control groups, respectively, after the treatment. This is the first report of the presence of live D. hominis larvae after the treatment of cattle with ivermectin and moxidectin in Brazil.

  5. Anti-inflammatory lanostanoids and lactone derivatives from Antrodia camphorata.

    PubMed

    Liaw, Chih-Chuang; Chen, Yu-Chang; Huang, Guan-Jhong; Tsai, Yao-Ching; Chien, Shih-Chang; Wu, Jyh-Horng; Wang, Sheng-Yang; Chao, Louis Kuoping; Sung, Ping-Jyun; Huang, Hui-Chi; Kuo, Yueh-Hsiung

    2013-04-26

    Four new lanostanoids, ethyl lucidenate A (1), ethyl lucidenate F (2), 15-O-acetylganolucidate A (3), and 3,11,15,23-tetraoxo-27ξ-lanosta-8,16-dien-26-oic acid (4), and two new lactone derivatives, 5-hydroxy-5-(methoxymethyl)-4-methylfuran-2(5H)-one (5) and 3-(4-methoxy-2-oxo-2H-pyran-6-yl)propanoic acid (6), together with four known compounds, 11α-hydroxy-3,7-dioxolanost-8,24(E)-dien-26- oic acid (7), 3,7,11-trioxo-5α-lanosta-8,24(E)-dien-26-oic acid (8), methyl 3,7,11,12,15,23-hexaoxo-5α-lanost-8-en-26-oate (9), and ethyl 3,7,11,12,15,23-hexaoxo-5α-lanost-8-en-26-oate (10), were characterized from Antrodia camphorata. The structures of these new compounds were determined by analysis of their spectroscopic data, including 1D and 2D NMR experiments. Ten components were evaluated for anti-inflammatory activity by examining their effect on LPS-iNOS-dependent NO production in murine macrophage (RAW 264.7) cells. Among them, compounds 1, 3, 7, 8, 9, and 10 significantly suppressed the NO concentration in LPS-treated RAW 264.7 cells with IC50 values ≤ 10 μM.

  6. Structure-Based Function Discovery of an Enzyme for the Hydrolysis of Phosphorylated Sugar Lactones

    PubMed Central

    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

  7. Sesquiterpene Lactones from Artemisia Genus: Biological Activities and Methods of Analysis

    PubMed Central

    Ivanescu, Bianca; Miron, Anca; Corciova, Andreia

    2015-01-01

    Sesquiterpene lactones are a large group of natural compounds, found primarily in plants of Asteraceae family, with over 5000 structures reported to date. Within this family, genus Artemisia is very well represented, having approximately 500 species characterized by the presence of eudesmanolides and guaianolides, especially highly oxygenated ones, and rarely of germacranolides. Sesquiterpene lactones exhibit a wide range of biological activities, such as antitumor, anti-inflammatory, analgesic, antiulcer, antibacterial, antifungal, antiviral, antiparasitic, and insect deterrent. Many of the biological activities are attributed to the α-methylene-γ-lactone group in their molecule which reacts through a Michael-addition with free sulfhydryl or amino groups in proteins and alkylates them. Due to the fact that most sesquiterpene lactones are thermolabile, less volatile compounds, they present no specific chromophores in the molecule and are sensitive to acidic and basic mediums, and their identification and quantification represent a difficult task for the analyst. Another problematic aspect is represented by the complexity of vegetal samples, which may contain compounds that can interfere with the analysis. Therefore, this paper proposes an overview of the methods used for the identification and quantification of sesquiterpene lactones found in Artemisia genus, as well as the optimal conditions for their extraction and separation. PMID:26495156

  8. First identification of three p-menthane lactones and their potential precursor, menthofuran, in red wines.

    PubMed

    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.

  9. In vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominatly Haemonchus contortus egg population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The anthelmintic activity of chicory (Cichorium intybus L.) herbage has been attributed to sesquiterpene lactones. Chicory leaves contain significant amounts of lactucin (LAC), 8-deoxylactucin (DOL), and lactucopicrin (LPIC), but the proportions of these three sesquiterpene lactones vary among fora...

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

    PubMed

    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.

  11. Dehydrocostus lactone enhances tumor necrosis factor-alpha-induced apoptosis of human leukemia HL-60 cells.

    PubMed

    Oh, G S; Pae, H O; Chung, H T; Kwon, J W; Lee, J H; Kwon, T O; Kwon, S Y; Chon, B H; Yun, Young Gab

    2004-05-01

    Sesquiterpene lactones have raised considerable interest because of their ability to block the activation of nuclear transcription factor-kappaB (NF-kappaB). NF-kappaB plays an important role in the resistance of cancer cells to the induction of apoptosis by anticancer drugs and tumor necrosis factor-alpha (TNF-alpha). Pharmacological inhibition of NF-kappaB offers the promise of enhancing the efficacy of anticancer therapies. Here, we demonstrate that dehydrocostus lactone (DL), the major sesquiterpene lactone isolated from the roots of Saussurea lappa, inhibits NF-kappaB activation by preventing TNF-alpha-induced degradation and phosphorylation of its inhibitory protein I-kappaB alpha in human leukemia HL-60 cells and that DL renders HL-60 cells susceptible to TNF-alpha-induced apoptosis by enhancing caspase-8 and caspase-3 activities.

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

    PubMed Central

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

    2014-01-01

    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. PMID:24984061

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

    PubMed

    Hansen, Mette R; Jakobsen, Tim H; Bang, Claus G; Cohrt, Anders Emil; Hansen, Casper L; Clausen, Janie W; Le Quement, Sebastian T; Tolker-Nielsen, Tim; Givskov, Michael; Nielsen, Thomas E

    2015-04-01

    In an attempt to devise new antimicrobial treatments for biofilm infections, the bacterial cell-cell communication system termed quorum sensing has emerged as an attractive target. It has proven possible to intercept the communication system by synthetic non-native ligands and thereby lower the pathogenesis and antibiotic tolerance of a bacterial biofilm. To identify the structural elements important for antagonistic or agonistic activity against the Pseudomonas aeruginosa LasR protein, we report the synthesis and screening of new triazole-containing mimics of natural N-acyl homoserine lactones. A series of azide- and alkyne-containing homoserine lactone building blocks was used to prepare an expanded set of 123 homoserine lactone analogues through a combination of solution- and solid-phase synthesis methods. The resulting compounds were subjected to cell-based quorum sensing screening assays, thereby revealing several bioactive compounds, including 13 compounds with antagonistic activity and 9 compounds with agonistic activity.

  14. Lipase-catalyzed ring-opening polymerization of lactones to polyesters and its mechanistic aspects.

    PubMed

    Namekawa, S; Suda, S; Uyama, H; Kobayashi, S

    1999-01-01

    Lipase catalysis induced a ring-opening polymerization of lactones with different ring-sizes. Small-size (four-membered) and medium-size lactones (six- and seven-membered) as well as macrolides (12-, 13-, 16-, and 17-membered) were subjected to lipase-catalyzed polymerization. The polymerization behaviors depended primarily on the lipase origin and the monomer structure. The macrolides showing much lower anionic polymerizability were enzymatically polymerized faster than epsilon-caprolactone. The granular immobilized lipase derived from Candida antartica showed extremely efficient catalysis in the polymerization of epsilon-caprolactone. Single-step terminal functionalization of the polyester was achieved by initiator and terminator methods. The enzymatic polymerizability of lactones was quantitatively evaluated by Michaelis-Menten kinetics.

  15. Macrocyclic lactones: A versatile source for omega radiohalogenated fatty acid analogs

    SciTech Connect

    Dougan, A.H.; Lyster, D.M.; Robertson, K.A.; Vincent, J.S.

    1984-01-01

    For each omega halogenated fatty acid there exists a potential omega hydroxy fatty acid and the corresponding macrocyclic lactone. The authors have utilized such lactones as starting materials for omega /sup 123/I fatty acid analogs intended for myocardial imaging. Macrocyclic musk lactones are industrially available; 120 analogs are described in the literature. The preparation requires saponification, tosylation, and radio-iodide substitution. Iodo-fatty acids are readily separated from tosylate fatty acids on TLC. While providing a secure source of 16-iodo-hexadecanoic acid and 17-iodo-heptadecanoic acid, the scheme allows ready access to a large number of untried fatty acid analogs. Examples presented are 16-iodo-hexadecanoic acid, 16-iodo-7-hexadecanoic acid, 16-iodo-12-oxa-hexadecanoic acid, 15-iodo-pentadecanoic acid, and 15-iodo-12-keto-pentadecanoic acid. Metabolic studies are in progress in mice and dogs to assess the utility of these analogs for myocardial imaging.

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

    PubMed

    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.

  17. Neocosmospora sp.-derived resorcylic acid lactones with in vitro binding capacity for human opioid and cannabinoid receptors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

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

    PubMed

    Okutsu, Noriya; Morohoshi, Tomohiro; Xie, Xiaonan; Kato, Norihiro; Ikeda, Tsukasa

    2015-12-30

    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.

  19. Synthesis and Antifeedant Activity of Racemic and Optically Active Hydroxy Lactones with the p-Menthane System

    PubMed Central

    Grudniewska, Aleksandra; Kłobucki, Marek; Dancewicz, Katarzyna; Szczepanik, Maryla; Gabryś, Beata; Wawrzeńczyk, Czesław

    2015-01-01

    Two racemic and two enantiomeric pairs of new δ-hydroxy-γ-lactones based on the p-menthane system were prepared from racemic and optically active cis- and trans-piperitols. The Johnson-Claisen rearrangement of the piperitols, epoxidation of the γδ-unsaturated esters, and acidic lactonization of the epoxy esters were described. The structures of the compounds were confirmed spectroscopically. The antifeedant activities of the hydroxy lactones and racemic piperitone were evaluated against three insect pests: lesser mealworm, Alphitobius diaperinus (Panzer); Colorado potato beetle, Leptinotarsa decemlineata (Say); and peach-potato aphid, Myzus persicae (Sulz.). The chemical transformation of piperitone by the introduction of a lactone moiety and a hydroxy group changed its antifeedant properties. Behavioral bioassays showed that the feeding deterrent activity depended on the insect species and the structure of the compounds. All hydroxy lactones deterred the settling of M. persicae. Among chewing insects, the highest sensitivity showed A. diaperinus adults. PMID:26132506

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

    PubMed Central

    Goh, Share Yuan; Tan, Wen-Si; Khan, Saad Ahmed; Chew, Hooi Pin; Kasim, Noor Hayaty Abu; Yin, Wai-Fong; Chan, Kok-Gan

    2014-01-01

    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). PMID:24854358

  1. Activation of antioxidant response element in mouse primary cortical cultures with sesquiterpene lactones isolated from Tanacetum parthenium

    PubMed Central

    Fischedick, Justin T; Standiford, Miranda; Johnson, Delinda A.; De Vos, Ric C.H.; Todorović, Slađana; Banjanac, Tijana; Verpoorte, Rob; Johnson, Jeffrey A.

    2012-01-01

    Tanacetum parthenium (Asteraceae) produces biologically active sesquiterpene lactones (SL). Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor known to activate a series of genes termed the antioxidant response element (ARE). Activation of the Nrf2/ARE may be useful for the treatment of neurodegenerative disease. In this study we isolated 11 sesquiterpene lactones from T. parthenium with centrifugal partition chromatography and semi-preparative HPLC. Compounds were screened in-vitro for their ability to activate the ARE on primary mouse cortical cultures as well as for their toxicity towards the cultures. All sesquiterpene lactones containing the α-methylene-γ-lactone moiety were able to activate the ARE although a number of compounds displayed significant cellular toxicity towards the cultures. The structure activity relationship of the sesquiterpene lactones indicate that the guaianolides isolated were more active and less toxic then the germacranolides. PMID:22923197

  2. Synthesis and Antifeedant Activity of Racemic and Optically Active Hydroxy Lactones with the p-Menthane System.

    PubMed

    Grudniewska, Aleksandra; Kłobucki, Marek; Dancewicz, Katarzyna; Szczepanik, Maryla; Gabryś, Beata; Wawrzeńczyk, Czesław

    2015-01-01

    Two racemic and two enantiomeric pairs of new δ-hydroxy-γ-lactones based on the p-menthane system were prepared from racemic and optically active cis- and trans-piperitols. The Johnson-Claisen rearrangement of the piperitols, epoxidation of the γδ-unsaturated esters, and acidic lactonization of the epoxy esters were described. The structures of the compounds were confirmed spectroscopically. The antifeedant activities of the hydroxy lactones and racemic piperitone were evaluated against three insect pests: lesser mealworm, Alphitobius diaperinus (Panzer); Colorado potato beetle, Leptinotarsa decemlineata (Say); and peach-potato aphid, Myzus persicae (Sulz.). The chemical transformation of piperitone by the introduction of a lactone moiety and a hydroxy group changed its antifeedant properties. Behavioral bioassays showed that the feeding deterrent activity depended on the insect species and the structure of the compounds. All hydroxy lactones deterred the settling of M. persicae. Among chewing insects, the highest sensitivity showed A. diaperinus adults.

  3. (1)H chemical shift differences of Prelog-Djerassi lactone derivatives: DFT and NMR conformational studies.

    PubMed

    Aímola, Túlio J; Lima, Dimas J P; Dias, Luiz C; Tormena, Cláudio F; Ferreira, Marco A B

    2015-02-21

    This work reports an experimental and theoretical study of the conformational preferences of several Prelog-Djerassi lactone derivatives, to elucidate the (1)H NMR chemical shift differences in the lactonic core that are associated with the relative stereochemistry of these derivatives. The boat-like conformation of explains the anomalous (1)H chemical shift between H-5a and H-5b, in which the two methyl groups (C-8 and C-9) face H-5b, leading to its higher shielding effect.

  4. Short Flow-Photochemistry Enabled Synthesis of the Cytotoxic Lactone (+)-Goniofufurone.

    PubMed

    Ralph, Michael; Ng, Sean; Booker-Milburn, Kevin I

    2016-03-04

    A photochemical approach to the cytotoxic lactone (+)-goniofufurone (1) is reported. Paternò-Büchi [2 + 2] photocycloaddition from known enol ether 4, derived from the readily available sugar d-isosorbide, yielded oxetane 7. This slow, dilute reaction was scaled up by using flow photochemistry to yield >40 g of 7. Installation of the key lactone ring was achieved via a unique Wacker-style oxidation of an enol-ether bond. Acid-catalyzed aqueous ring opening provided 1 in five steps from 4 (11.5% overall).

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

    PubMed

    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.

  6. Purification and identification of antimicrobial sesquiterpene lactones from yacon (Smallanthus sonchifolius) leaves.

    PubMed

    Lin, Fengqiu; Hasegawa, Morifumi; Kodama, Osamu

    2003-10-01

    The extraction of yacon [Smallanthus sonchifolius (Poepp. and Endl.) H. Robinson; Asteraceae] leaves and chromatographic separation yielded two new antibacterial melampolide-type sesquiterpene lactones, 8beta-tigloyloxymelampolid-14-oic acid methyl ester and 8beta-methacryloyloxymelampolid-14-oic acid methyl ester, as well as the four known melampolides, sonchifolin, uvedalin, enhydrin and fluctuanin. The newly identified compound, 8beta-methacryloyloxymelampolid-14-oic acid methyl ester, exhibited potent antimicrobial activity against Bacillus subtilis and Pyricularia oryzae, while 8beta-tigloyloxymelampolid-14-oic acid methyl ester showed lower activity. Fluctuanin exhibited the strongest antibacterial activity against B. subtilis among these six sesquiterpene lactones.

  7. [Effects of ginkgo diterpene lactones meglumine injection's activated carbon adsorption technology on officinal components].

    PubMed

    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.

  8. Synthesis of “clickable” acylhomoserine lactone quorum sensing probes: unanticipated effects on mammalian cell activation

    PubMed Central

    Garner, Amanda L.; Yu, Jing; Struss, Anjali Kumari; Lowery, Colin A.; Zhu, Jie; Kim, Sook Kyung; Park, Junguk; Mayorov, Alexander V.; Kaufmann, Gunnar F.; Kravchenko, Vladimir V.; Janda, Kim D.

    2010-01-01

    Alkynyl- and azido-tagged 3-oxo-C12-acylhomoserine lactone probes have been synthesized to examine their potential utility as probes for discovering the mammalian protein target of the Pseudomonas aeruginosa autoinducer, 3-oxo-C12-acylhomoserine lactone. Although such substitutions are commonly believed to be quite conservative, from these studies, we have uncovered a drastic difference in activity between the alkynyl- and azido-modified compounds, and provide an example where such structural modification has proved to be much less than conservative. PMID:21190852

  9. Antibacterial and cytotoxic activities of the sesquiterpene lactones cnicin and onopordopicrin.

    PubMed

    Bach, Sandra M; Fortuna, Mario A; Attarian, Rodgoun; de Trimarco, Juliana T; Catalán, César A N; Av-Gay, Yossef; Bach, Horacio

    2011-02-01

    The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.

  10. Two new sesquiterpene lactones with the sulfonic acid group from Saussurea lappa.

    PubMed

    Yin, Hong-quan; Fu, Hong-wei; Hua, Hui-ming; Qi, Xiu-lan; Li, Wen; Sha, Yi; Pei, Yue-hu

    2005-07-01

    Two new sesquiterpene lactones with the unusual sulfonic acid group, 13-sulfo-dihydrosantamarine (1) and 13-sulfo-dihydroreynosin (2), have been isolated from the roots of Saussurea lappa C. Their structures, including the absolute configurations, were elucidated by spectroscopic methods.

  11. delta-Lactone from Oedogonium capillare and their effects on rat ileum.

    PubMed

    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.

  12. A five-membered lactone prodrug of CBI-based analogs of the duocarmycins

    PubMed Central

    Uematsu, Mika; Brody, Daniel M.; Boger, Dale L.

    2014-01-01

    The preparation, characterization and examination of the CBI-based 5-membered lactone 5 capable of serving as a prodrug or protein (antibody) conjugation reagent are disclosed along with its incorporation into the corresponding CC-1065 and duocarmycin analog 6, and the establishment of their properties. PMID:26069351

  13. A grapevine cytochrome P450 generates the precursor of wine lactone, a key odorant in wine.

    PubMed

    Ilc, Tina; Halter, David; Miesch, Laurence; Lauvoisard, Florian; Kriegshauser, Lucie; Ilg, Andrea; Baltenweck, Raymonde; Hugueney, Philippe; Werck-Reichhart, Danièle; Duchêne, Eric; Navrot, Nicolas

    2017-01-01

    Monoterpenes are important constituents of the aromas of food and beverages, including wine. Among monoterpenes in wines, wine lactone has the most potent odor. It was proposed to form via acid-catalyzed cyclization of (E)-8-carboxylinalool during wine maturation. It only reaches very low concentrations in wine but its extremely low odor detection threshold makes it an important aroma compound. Using LC-MS/MS, we show here that the (E)-8-carboxylinalool content in wines correlates with their wine lactone content and estimate the kinetic constant for the very slow formation of wine lactone from (E)-8-carboxylinalool. We show that (E)-8-carboxylinalool is accumulated as a glycoside in grape (Vitis vinifera) berries and that one of the cytochrome P450 enzymes most highly expressed in maturing berries, CYP76F14, efficiently oxidizes linalool to (E)-8-carboxylinalool. Our analysis of (E)-8-carboxylinalool in Riesling × Gewurztraminer grapevine progeny established that the CYP76F14 gene co-locates with a quantitative trait locus for (E)-8-carboxylinalool content in grape berries. Our data support the role of CYP76F14 as the major (E)-8-carboxylinalool synthase in grape berries and the role of (E)-8-carboxylinalool as a precursor to wine lactone in wine, providing new insights into wine and grape aroma metabolism, and new methods for food and aroma research and production.

  14. Structural and Sensory Characterization of Novel Sesquiterpene Lactones from Iceberg Lettuce.

    PubMed

    Mai, Franziska; Glomb, Marcus A

    2016-01-13

    Lactuca sativa var. capitate (iceberg lettuce) is a delicious vegetable and popular for its mild taste. Nevertheless, iceberg lettuce is a source of bitter substances, such as the sesquiterpene lactones. Chemical investigations on the n-butanol extract led to the isolation of three novel sesquiterpene lactones. All compounds were isolated by multilayer countercurrent chromatography followed by preparative high-performance liquid chromatography. The structures were verified by means of spectroscopic methods, including NMR and mass spectrometry techniques. For the first time 11ß,13-dihydrolactucin-8-O-sulfate (jaquinelin-8-O-sulfate) was structurally elucidated and identified in plants. In addition, the sesquiterpene lactones cichorioside B and 8-deacetylmatricarin-8-O-sulfate were identified as novel ingredients of iceberg lettuce. Further flowering plants in the daisy family Asteraceae were examined for the above three compounds. At least one of the compounds was identified in nine plants. The comparison between the lettuce butt end and the leaves of five types of the Cichorieae tribe showed an accumulation of the compounds in the butt end. Further experiments addressed the impact of sesquiterpene lactones on color formation and bitter taste.

  15. New 3-methyoxyflavones, an iridoid lactone and a flavonol from duroia hirsuta

    PubMed

    Aquino; Tommasi; Tapia; Lauro; Rastrelli

    1999-04-01

    Investigation of the roots of Duroia hirsuta from Ecuador yielded the iridoid lactone duroin (1) together with 3,7,3', 5'-tetramethoxy-4'-hydroxyflavone (2), 3,7,3'-trimethoxy-4', 5'-dihydroxyflavone (3), and 7,3',5'-trimethoxy-3, 4'-dihydroxyflavone (4) as novel constituents.

  16. Structure-hepatoprotective activity relationship study of sesquiterpene lactones: A QSAR analysis

    NASA Astrophysics Data System (ADS)

    Paukku, Yuliya; Rasulev, Bakhtiyor; Syrov, Vladimir; Khushbaktova, Zainab; Leszczynski, Jerzy

    This study has been carried out using quantitative structure-activity relationship analysis (QSAR) for 22 sesquiterpene lactones to correlate and predict their hepatoprotective activity. Sesquiterpenoids, the largest class of terpenoids, are a widespread group of substances occurring in various plant organisms. QSAR analysis was carried out using methods such as genetic algorithm for variables selection among generated and calculated descriptors and multiple linear regression analysis. Quantum-chemical calculations have been performed by density functional theory at B3LYP/6-311G(d, p) level for evaluation of electronic properties using reference geometries optimized by semi-empirical AM1 approach. Three models describing hepatoprotective activity values for series of sesquiterpene lactones are proposed. The obtained models are useful for description of sesquiterpene lactones hepatoprotective activity and can be used to estimate the hepatoprotective activity of new substituted sesquiterpene lactones. The models obtained in our study show not only statistical significance, but also good predictive ability. The estimated predictive ability (rtest2) of these models lies within 0.942-0.969.

  17. Divergent synthesis and chemical reactivity of bicyclic lactone fragments of complex rearranged spongian diterpenes.

    PubMed

    Schnermann, Martin J; Beaudry, Christopher M; Genung, Nathan E; Canham, Stephen M; Untiedt, Nicholas L; Karanikolas, Breanne D W; Sütterlin, Christine; Overman, Larry E

    2011-11-02

    The synthesis and direct comparison of the chemical reactivity of the two highly oxidized bicyclic lactone fragments found in rearranged spongian diterpenes (8-substituted 6-acetoxy-2,7-dioxabicyclo[3.2.1]octan-3-one and 6-substituted 7-acetoxy-2,8-dioxabicyclo[3.3.0]octan-3-one) are reported. Details of the first synthesis of the 6-acetoxy-2,7-dioxabicyclo[3.2.1]octan-3-one ring system, including an examination of several possibilities for the key bridging cyclization reaction, are described. In addition, the first synthesis of 7-acetoxy-2,8-dioxabicyclo[3.3.0]octanones containing quaternary carbon substituents at C6 is disclosed. Aspects of the chemical reactivity and Golgi-modifying properties of these bicyclic lactone analogs of rearranged spongian diterpenes are also reported. Under both acidic and basic conditions, 8-substituted 2,7-dioxabicyclo[3.2.1]octanones are converted to 6-substituted-2,8-dioxabicyclo[3.3.0]octanones. Moreover, these dioxabicyclic lactones react with primary amines and lysine side chains of lysozyme to form substituted pyrroles, a conjugation that could be responsible for the unique biological properties of these compounds. These studies demonstrate that acetoxylation adjacent to the lactone carbonyl group, in either the bridged or fused series, is required to produce fragmented Golgi membranes in the pericentriolar region that is characteristic of macfarlandin E.

  18. Concurrent and supercritical fluid chromatographic analysis of Terpene Lactones and ginkolic acids in Ginko biloba

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Developmental and Environmental Effects on Sesquiterpene Lactones in Cultivated Arnica montana L.

    PubMed

    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.

  20. SELECTIVE HYDROGENATION OF ANHYDRIDES TO LACTONES UNDER SUPERCRITICAL CARBON DIOXIDE MEDIUM

    EPA Science Inventory

    Selective Hydrogenation of Anhydrides to Lactones Under Supercritical Carbon Dioxide Medium

    Endalkachew Sahle-Demessie Unnikrishnan R Pillai
    U.S. EPA , 26 W. Martin Luther King Dr. Cincinnati, OH 45268 Phone: 513-569-7739
    Fax: 513-569-7677
    Abstract:
    Hydrogenat...

  1. Ficuschlorins A - D, lactone Chlorins from the leaves of ficus microcarpa.

    PubMed

    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.

  2. Anthelmintic potential of chicory forage is influenced by sesquiterpene lactone composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The anthelmintic activity of chicory (Cichorium intybus L.) herbage has been attributed to sesquiterpene lactones (SLs). Chicory leaves contain lactucin (LAC), 8-deoxylactucin (DOL), and lactucopicrin (LPIC), but the amounts of these three SLs vary among cultivars. The objective of this study was...

  3. Minimal structural requirements of alkyl γ-lactones capable of antagonizing the cocaine-induced motility decrease in planarians.

    PubMed

    Baker, Debra; Deats, Sean; Boor, Peter; Pruitt, James; Pagán, Oné R

    2011-11-01

    We recently reported that the natural cyclic lactone, parthenolide, and related analogs prevent the expression of behavioral effects induced by cocaine in planarians and that parthenolide's γ-lactone ring is required for this effect. In the present work, we tested a series of alkyl γ-lactones with varying chain length (1-8 carbons) to determine their ability to antagonize the planarian motility decrease induced by 200 μM cocaine. Alkyl lactones with up to a 4-carbon alkyl chain did not affect planarian motility or antagonized the cocaine-induced motility decrease; only the compound γ-nonalactone (a γ-lactone with a 5-carbon chain) was able to prevent the cocaine-induced behavioral patterns, while alkyl lactones with longer carbon chains failed to prevent the cocaine-induced effects. Thus, we conclude that the optimal structural features of this family of compounds to antagonize cocaine's effect in this experimental system is a γ-lactone ring with at a 5-carbon long functional group.

  4. Selective enzymatic hydrolysis of chlorogenic acid lactones in a model system and in a coffee extract. Application to reduction of coffee bitterness.

    PubMed

    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.

  5. Excretion of Glycolate, Mesotartrate and Isocitrate Lactone by Synchronized Cultures of Ankistrodesmus braunii1

    PubMed Central

    Chang, Wei-Hsein; Tolbert, N. E.

    1970-01-01

    Fixation of 14CO2 by synchronized cultures of Ankistrodesmus braunii was highest for young growing cells, low for mature cells, and lowest for dividing cells. The amount of 14C excreted during photosynthesis followed the same trend. Cells at the end of the growing phase, after 10 hours of a 16-hour light phase, excreted nearly 35% of the total 14C fixed as one product, glycolate. Dividing cells from the dark phase, when tested in the light, excreted only 4% as much glycolate-14C as the young growing cells. Dividing cells also excreted as much mesotartrate as glycolate and also some isocitrate lactone and an unidentified acid. None of these excreted acids were found inside the cells in significant amounts. Methods for isolation and identification of the excreted acids are present. With 14C-labeled algae, it was shown that the excretion of glycolate was light-dependent and inhibited by 1,1-dimethyl-3-(p-chlorophenyl) urea. The excretion of labeled mesotartrate, isocitrate lactone, and an unknown acid, but not glycolate, also occurred in the dark. The excreted mesotartrate was predominantly carboxyl-labeled even after long periods of 14CO2 fixation. Since glycolate is known to be uniformly labeled, glycolate could not be the precursor of the carboxyl-labeled mesotartrate. The reason for the specific excretion of glycolate, mesotartrate, and isocitrate lactone is not known, but the metabolism of all three acids by the algae may be limited and each can form dilactides or lactones by dehydration. In this context isocitrate lactone was excreted rather than the free acid. PMID:16657471

  6. Mode of Action of the Sesquiterpene Lactones Psilostachyin and Psilostachyin C on Trypanosoma cruzi.

    PubMed

    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

  7. Mode of Action of the Sesquiterpene Lactones Psilostachyin and Psilostachyin C on Trypanosoma cruzi

    PubMed Central

    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

  8. 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.

    PubMed

    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.

  9. Effects of α,β-unsaturated lactones on larval survival and gut trypsin as well as oviposition response of Aedes aegypti.

    PubMed

    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.

  10. Defining the structure and function of acyl-homoserine lactone autoinducers.

    PubMed

    Churchill, Mair E A; Sibhatu, Hiruy M; Uhlson, Charis L

    2011-01-01

    Quorum sensing plays a central role in regulating many community-derived symbiotic and pathogenic relationships of bacteria, and as such has attracted much attention in recent years. Acyl-homoserine lactones (AHLs) are important signaling molecules in the quorum sensing gene-regulatory processes found in numerous gram-negative species of bacteria that interact with eukaryotic organisms. AHLs are produced by acyl-homoserine lactone synthases. Bacteria can have multiple genes for AHL synthase enzymes, and such species are likely to produce several different types of AHLs. Determination of the types and the relative amounts of AHLs produced by AHL synthases in bacteria under varied conditions provides important insights into the mechanism of AHL synthase function and the regulation of transcriptional cascades initiated by quorum sensing signaling. This chapter describes a mass spectrometry method for determining the types and relative amounts of AHLs present in a sample.

  11. Evaluation of sesquiterpene lactone fraction of Saussurea lappa on transudative, exudative and proliferative phases of inflammation.

    PubMed

    Damre, A A; Damre, A S; Saraf, M N

    2003-08-01

    The sesquiterpene lactone fraction of Saussurea lappa roots was evaluated for its effect on the transudative, exudative and proliferative phases of inflammation using the cotton pellet granuloma assay in rats. The fraction (25-100 mg/kg, p.o.) showed significant dose-dependent inhibition of the increase in wet weight of the cotton pellet at 3 h (transudative phase), leakage of dye from the bloodstream around granuloma at 24 h (exudative phase) and increase in dry weight of the cotton pellet on day 6 (proliferative phase). It significantly lowered the elevated biochemical parameters such as alkaline phosphatase, acid phosphatase, gamma-glutamyltranspeptidase and significantly elevated the lowered albumin concentration in serum. The studies suggest that the antiinflammatory activity of the sesquiterpene lactone fraction of S. lappa may, in part, be due to stabilization of lysosomal membranes and an antiproliferative effect.

  12. Isolation of two new bioactive sesquiterpene lactone glycosides from the roots of Ixeris dentata.

    PubMed

    Park, SeonJu; Nhiem, Nguyen Xuan; Lee, Taek Hwan; Kim, Nanyoung; Kim, Sun Yeou; Chae, Han-Jung; Kim, Seung Hyun

    2015-10-15

    Two new sesquiterpene lactone glycosides, 3-O-β-d-glucopyranosyl-8-hydroxy-(1,5,6,7,11)-guaia-3,10(14)-dien-12,6-olide (1) and 3-O-β-d-glucopyranosyl-8-(4-hydroxyphenylacetyloxy)-(1.5.6,7)-guaia-3,10(14),11(13)-trien-12,6-olide (2), and 12 known sesquiterpene lactone derivatives (3-14) were isolated from the roots of Ixeris dentata. Their structures were determined by extensive spectroscopic methods including 1D and 2D NMR and MS spectra data. All compounds were tested for their ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cell. 3-O-β-d-Glucopyranosyl-8-(4-hydroxyphenylacetyloxy)-(1.5.6,7)-guaia-3,10(14),11(13)-trien-12,6-olide (2) showed the most potent inhibitory activity at a concentration of 20μM.

  13. Defining the structure and function of acyl-homoserine lactone autoinducers

    PubMed Central

    Churchill, Mair E.A.; Sibhatu, Hiruy M.; Uhlson, Charis L.

    2012-01-01

    Quorum sensing plays a central role in regulating many community derived symbiotic and pathogenic relationships of bacteria, and as such has attracted much attention in recent years. Acyl-homoserine lactones (AHLs) are important signaling molecules in the quorum sensing gene regulatory processes found in numerous gram-negative species of bacteria that interact with eukaryotic organisms. AHLs are produced by acyl-homoserine lactone synthases. Bacteria can have multiple genes for AHL synthase enzymes, and such species are likely to produce several different types of AHLs. Determination of the types and the relative amounts of AHLs produced by AHL synthases in bacteria under varied conditions provides important insights into the mechanism of AHL synthase function and the regulation of transcriptional cascades initiated by quorum sensing signaling. This chapter describes a mass spectrometry method for determining the types and relative amounts of AHLs present in a sample. PMID:21031311

  14. Covalent modification of human serum albumin by the natural sesquiterpene lactone parthenolide.

    PubMed

    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.

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

    PubMed

    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.

  16. Method to produce water-soluble sugars from biomass using solvents containing lactones

    DOEpatents

    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.

  17. 12α-Hy­droxy-3,27-dioxooleanano-28,13-lactone

    PubMed Central

    Hu, Jun-yi; Wu, Gang-gang; Xu, Ying-qian; Xiao, Guo-yong; Lei, Peng

    2012-01-01

    There are two independent mol­ecules in the asymmetric unit of the title compound, C30H44O5. They comprise a triterpenoid skeleton of five six-membered rings and a five-membered lactone ring. The five six-membered rings are all trans-fused. In both independent mol­ecules the D rings adopt a slightly distorted half-chair conformation due the presence of the lactone ring while the other four six-membered rings all adopt chair conformations. The characteristic carbon–carbon double bond of the oleanoic skeleton is absent. Inter­molecular O—H⋯O hydrogen bonds between the hy­droxy and carbonyl groups occur in the crystal structure. PMID:22719397

  18. Synthesis and insect antifeedant activity of precocene derivatives with lactone moiety.

    PubMed

    Szczepanik, Maryla; Obara, Robert; Szumny, Antoni; Gabryś, Beata; Halarewicz-Pacan, Aleksandra; Nawrot, Jan; Wawrzeńczyk, Czesław

    2005-07-27

    Starting from precocenes I and II, four of their derivatives with a lactone moiety were obtained. The compounds have been assessed as antifeedants against several diverse insect species including the storage pests the confused flour beetle (Tribolium confusum Duv., larvae and adults), the granary weevil beetle (Sitophilus granarius L., adults), and the khapra beetle (Trogoderma granarium Ev., larvae) and against the herbivorous pest insects Colorado potato beetle (Leptinotarsa decemlineata Say, adults and larvae) and aphids (Myzus persicae Sulz.). Precocenes, especially precocene II, showed a very strong antifeedant effect against all storage pests and aphids. The introduction of a lactone moiety caused a decrease in antifeedant activity against these species. Both precocenes were moderately active against L. decemlineata adults. The best antifeedants to this species were precocene derivatives, especially iodolactones. The introduction of iodine into a molecule had a great effect on the antifeedant activity of those compounds.

  19. Cascade Synthesis of Five-Membered Lactones using Biomass-Derived Sugars as Carbon Nucleophiles.

    PubMed

    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.

  20. Stereodivergent organocatalytic intramolecular Michael addition/lactonization for the asymmetric synthesis of substituted dihydrobenzofurans and tetrahydrofurans.

    PubMed

    Belmessieri, Dorine; de la Houpliere, Alix; Calder, Ewen D D; Taylor, James E; Smith, Andrew D

    2014-07-28

    A stereodivergent asymmetric Lewis base catalyzed Michael addition/lactonization of enone acids into substituted dihydrobenzofuran and tetrahydrofuran derivatives is reported. Commercially available (S)-(-)-tetramisole hydrochloride gives products with high syn diastereoselectivity in excellent enantioselectivity (up to 99:1 d.r.syn/anti , 99 % eesyn ), whereas using a cinchona alkaloid derived catalyst gives the corresponding anti-diastereoisomers as the major product (up to 10:90 d.r.syn/anti , 99 % eeanti ).

  1. Development of Acid Functional Groups and Lactones During the Thermal Degradation of Wood and Wood Components

    USGS Publications Warehouse

    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.

  2. Quorum quenching by an N-acyl-homoserine lactone acylase from Pseudomonas aeruginosa PAO1.

    PubMed

    Sio, Charles F; Otten, Linda G; Cool, Robbert H; Diggle, Stephen P; Braun, Peter G; Bos, Rein; Daykin, Mavis; Cámara, Miguel; Williams, Paul; Quax, Wim J

    2006-03-01

    The virulence of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 is controlled by an N-acyl-homoserine lactone (AHL)-dependent quorum-sensing system. During functional analysis of putative acylase genes in the P. aeruginosa PAO1 genome, the PA2385 gene was found to encode an acylase that removes the fatty acid side chain from the homoserine lactone (HSL) nucleus of AHL-dependent quorum-sensing signal molecules. Analysis showed that the posttranslational processing of the acylase and the hydrolysis reaction type are similar to those of the beta-lactam acylases, strongly suggesting that the PA2385 protein is a member of the N-terminal nucleophile hydrolase superfamily. In a bioassay, the purified acylase was shown to degrade AHLs with side chains ranging in length from 11 to 14 carbons at physiologically relevant low concentrations. The substituent at the 3' position of the side chain did not affect activity, indicating broad-range AHL quorum-quenching activity. Of the two main AHL signal molecules of P. aeruginosa PAO1, N-butanoyl-l-homoserine lactone (C4-HSL) and N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL), only 3-oxo-C12-HSL is degraded by the enzyme. Addition of the purified protein to P. aeruginosa PAO1 cultures completely inhibited accumulation of 3-oxo-C12-HSL and production of the signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone and reduced production of the virulence factors elastase and pyocyanin. Similar results were obtained when the PA2385 gene was overexpressed in P. aeruginosa. These results demonstrate that the protein has in situ quorum-quenching activity. The quorum-quenching AHL acylase may enable P. aeruginosa PAO1 to modulate its own quorum-sensing-dependent pathogenic potential and, moreover, offers possibilities for novel antipseudomonal therapies.

  3. Quorum Quenching by an N-Acyl-Homoserine Lactone Acylase from Pseudomonas aeruginosa PAO1

    PubMed Central

    Sio, Charles F.; Otten, Linda G.; Cool, Robbert H.; Diggle, Stephen P.; Braun, Peter G.; Bos, Rein; Daykin, Mavis; Cámara, Miguel; Williams, Paul; Quax, Wim J.

    2006-01-01

    The virulence of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 is controlled by an N-acyl-homoserine lactone (AHL)-dependent quorum-sensing system. During functional analysis of putative acylase genes in the P. aeruginosa PAO1 genome, the PA2385 gene was found to encode an acylase that removes the fatty acid side chain from the homoserine lactone (HSL) nucleus of AHL-dependent quorum-sensing signal molecules. Analysis showed that the posttranslational processing of the acylase and the hydrolysis reaction type are similar to those of the beta-lactam acylases, strongly suggesting that the PA2385 protein is a member of the N-terminal nucleophile hydrolase superfamily. In a bioassay, the purified acylase was shown to degrade AHLs with side chains ranging in length from 11 to 14 carbons at physiologically relevant low concentrations. The substituent at the 3′ position of the side chain did not affect activity, indicating broad-range AHL quorum-quenching activity. Of the two main AHL signal molecules of P. aeruginosa PAO1, N-butanoyl-l-homoserine lactone (C4-HSL) and N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL), only 3-oxo-C12-HSL is degraded by the enzyme. Addition of the purified protein to P. aeruginosa PAO1 cultures completely inhibited accumulation of 3-oxo-C12-HSL and production of the signal molecule 2-heptyl-3-hydroxy-4(1H)-quinolone and reduced production of the virulence factors elastase and pyocyanin. Similar results were obtained when the PA2385 gene was overexpressed in P. aeruginosa. These results demonstrate that the protein has in situ quorum-quenching activity. The quorum-quenching AHL acylase may enable P. aeruginosa PAO1 to modulate its own quorum-sensing-dependent pathogenic potential and, moreover, offers possibilities for novel antipseudomonal therapies. PMID:16495538

  4. Enantioselective Trifluoromethylthiolating Lactonization Catalyzed by an Indane-Based Chiral Sulfide.

    PubMed

    Liu, Xiang; An, Rui; Zhang, Xuelin; Luo, Jie; Zhao, Xiaodan

    2016-05-04

    Enantioselective trifluoromethylthiolation, especially of alkenes, is a challenging task. In this work, we have developed an efficient approach for enantioselective trifluoromethylthiolating lactonization by designing an indane-based bifunctional chiral sulfide catalyst and a shelf-stable electrophilic SCF3 reagent. The desired products were formed with diastereoselectivities of >99:1 and good to excellent enantioselectivities. The transformation represents the first enantioselective trifluoromethylthiolation of alkenes and the first enantioselective trifluoromethylthiolation that is enabled by a catalyst with a Lewis basic sulfur center.

  5. Quorum Quenching: Enzymatic Disruption of N-Acylhomoserine Lactone-Mediated Bacterial Communication in Burkholderia thailandensis

    PubMed Central

    Ulrich, Ricky L.

    2004-01-01

    Many species of gram-negative bacteria communicate by synthesizing, secreting, and responding to N-acylhomoserine lactones (AHLs), a mechanism termed quorum sensing. Several investigations have characterized numerous AHL-degrading enzymes (AiiA lactonases) encoded by environmental isolates of Bacillus spp. The Burkholderia thailandensis quorum system is comprised of at least three AHL synthases (AHSs) and five transcriptional regulators belonging to the LuxIR class of proteins. Expression of the Bacillus anthracis (Ames strain) AiiA lactonase in B. thailandensis completely abolished the accumulation of N-decanoylhomoserine lactone (C10-HSL) and N-octanoylhomoserine lactone (C8-HSL), reduced N-hexanoylhomoserine lactone (C6-HSL) levels, altered both swarming and twitching motility, caused a significant increase in generation time, and affected carbon metabolism. In contrast, heterologous expression of the Bacillus cereus strain A24 AiiA lactonase in B. thailandensis reduced the concentrations of C6-HSL, C8-HSL, and C10-HSL to nondetectable levels; altered both swarming and twitching motility; and caused fluctuations in carbon utilization. Individual disruption of the B. thailandensis AHSs, specifically disruption of the btaI1 and btaI3 genes, which encode the proteins that direct the synthesis of C8-HSL and C6-HSL, respectively, caused the hyper-beta-hemolysis of sheep erythrocytes on blood agar plates. In contrast, AHL cleavage in B. thailandensis by the Bacillus AiiA lactonases failed to enhance beta-hemolytic activity. The results of this study demonstrate that heterologous expression of Bacillus sp. AiiA lactonases in B. thailandensis reduced AHL accumulation, affected both swarming and twitching motility, increased generation time, altered substrate utilization, and prevented the beta-hemolysis of sheep erythrocytes. PMID:15466564

  6. Quorum quenching: enzymatic disruption of N-acylhomoserine lactone-mediated bacterial communication in Burkholderia thailandensis.

    PubMed

    Ulrich, Ricky L

    2004-10-01

    Many species of gram-negative bacteria communicate by synthesizing, secreting, and responding to N-acylhomoserine lactones (AHLs), a mechanism termed quorum sensing. Several investigations have characterized numerous AHL-degrading enzymes (AiiA lactonases) encoded by environmental isolates of Bacillus spp. The Burkholderia thailandensis quorum system is comprised of at least three AHL synthases (AHSs) and five transcriptional regulators belonging to the LuxIR class of proteins. Expression of the Bacillus anthracis (Ames strain) AiiA lactonase in B. thailandensis completely abolished the accumulation of N-decanoylhomoserine lactone (C(10)-HSL) and N-octanoylhomoserine lactone (C(8)-HSL), reduced N-hexanoylhomoserine lactone (C(6)-HSL) levels, altered both swarming and twitching motility, caused a significant increase in generation time, and affected carbon metabolism. In contrast, heterologous expression of the Bacillus cereus strain A24 AiiA lactonase in B. thailandensis reduced the concentrations of C(6)-HSL, C(8)-HSL, and C(10)-HSL to nondetectable levels; altered both swarming and twitching motility; and caused fluctuations in carbon utilization. Individual disruption of the B. thailandensis AHSs, specifically disruption of the btaI1 and btaI3 genes, which encode the proteins that direct the synthesis of C(8)-HSL and C(6)-HSL, respectively, caused the hyper-beta-hemolysis of sheep erythrocytes on blood agar plates. In contrast, AHL cleavage in B. thailandensis by the Bacillus AiiA lactonases failed to enhance beta-hemolytic activity. The results of this study demonstrate that heterologous expression of Bacillus sp. AiiA lactonases in B. thailandensis reduced AHL accumulation, affected both swarming and twitching motility, increased generation time, altered substrate utilization, and prevented the beta-hemolysis of sheep erythrocytes.

  7. Two lactones in the androconial scent of the lycaenid butterfly Celastrina argiolus ladonides

    NASA Astrophysics Data System (ADS)

    Ômura, Hisashi; Yakumaru, Kazuhisa; Honda, Keiichi; Itoh, Takao

    2013-04-01

    Male adult butterflies of many species have characteristic odors originating from the disseminating organs known as androconia. Despite the fact that androconia exist in several species, there have been few investigations on adult scents from the lycaenid species. Celastrina argiolus ladonides (Lycaenidae) is a common species in Eurasia. We have reported that male adults of this species emit a faint odor, and the major components causing this odor have been newly found in the Insecta. By using field-caught individuals, we determined the chemical nature and location of this odor in the butterfly. Gas chromatography-mass spectrometry (GC-MS) analyses revealed that two lactone compounds, lavender lactone and δ-decalactone, are present in the extracts of males but absent in those of the females. On an average, approximately 50 ng of each compound was found per male. Chiral GC analyses performed using enantiomerically pure standards revealed that the natural lavender lactone was a mixture of two enantiomers with an R/ S ratio of 32:68, whereas the natural δ-decalactone contained only the R-enantiomer. When the analyses were conducted using different parts—forewings, hindwings, and body—of three males, the lactones were more abundantly found on the forewings and hindwings than on the body. Microscopic observation of the wings demonstrated that battledore scales known as androconia are scattered on the upper surface of both the wings of C. argiolus ladonides males. These results indicate that the specialized scales on the wings of males serve as scent-disseminating organs.

  8. Design of Countercurrent Separation of Ginkgo biloba Terpene Lactones by Nuclear Magnetic Resonance

    PubMed Central

    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

  9. Amino acid-derived heterocycles as combinatorial library targets: spirocyclic ketal lactones.

    PubMed

    Trump, Ryan P; Bartlett, Paul A

    2003-01-01

    The spirocyclic ketal-lactone frameworks of 3 and 4 were designed as novel structures amenable to combinatorial synthesis. The synthesis of representative analogues was developed in solution and on solid support, the scope of effective input materials was determined, and the stability and stereochemistry of the products was evaluated. The spirocycles are obtained in modest overall yields (5-36%) and excellent purities (>72%) and offer a promising motif for combinatorial prospecting libraries.

  10. Physalindicanols, New Biogenetic Precursors of C28-Steroidal Lactones from Physalis minima var. indica.

    PubMed

    Sinha, S C; Ali, A; Bagchi, A; Sahai, M; Ray, A B

    1987-02-01

    The structures of two isomeric C (28)-sterols isolated from PHYSALIS MINIMA Linn. var. INDICA were elucidated as ergosta-5,25-dien-3beta,24zeta,-diol and ergosta-5,24(28)-dien-3beta,25-diol on the basis of detailed spectral analysis. The isolated sterols are regarded as precursors in the elaboration of complex C (28)-steroidal lactones, native in this plant and related species.

  11. Lactones 35 [1]. Metabolism of iodolactones with cyclohexane ring in Absidia cylindrospora culture.

    PubMed

    Gładkowski, Witold; Mazur, Marcelina; Białońska, Agata; Wawrzeńczyk, Czesław

    2011-04-07

    The metabolism of δ-iodo-γ-lactones containing cyclohexane ring with an increasing number of methyl substituents in Absidia cylindrospora was studied and seven metabolites were isolated as the products of biotransformations of these substrates. They were formed as the result of various dehalogenation pathways and four of them (hydroxylactones and epoxylactone) turned out to be new compounds. The conversion of substrates ranged from 60% to 90% and the highest conversion was observed for the iodolactone with an unsubstituted cyclohexane ring. The products were fully characterized by the spectroscopic methods and for the hydroxylactone with gem-dimethyl group at C-5 and hydroxylactone with trimethylcyclohexane system the crystal structures were obtained. The main products formed in the process of hydrolytic dehalogenation were δ-hydroxy-γ-lactones with the hydroxy group located cis in relation to lactone moiety. In case of lactone with 4,4,6-trimethylcyclohexane system the dehydrohalogenation followed by the epoxidation of double bond was also observed. One of the metabolites 4,5-epoxy-2,2,6-trimethyl-9-oxabicyclo[4.3.0]nonan-8-one was formed in the sequence of three reactions: hydroxylation at C-5, translactonization and intramolecular nucleophilic substitution of the iodine by the hydroxy group. Some of the isolated products of transformation of the iodolactone with trimethylcyclohexane system were obtained as the single enantiomers. The application of fungi studied to the dehalogenation of iodolactones could be a useful method in the production of new metabolites with oxygen-containing functional groups with antifeedant activity.

  12. Reversal of cocaine-induced planarian behavior by parthenolide and related sesquiterpene lactones.

    PubMed

    Pagán, Oné R; Rowlands, Amanda L; Azam, Mahrukh; Urban, Kimberly R; Bidja, Apurva H; Roy, Danielle M; Feeney, Ryan B; Afshari, Lilly K

    2008-04-01

    Here we report the prevention and reversal of cocaine-induced behaviors in planarian worms by parthenolide and two related cyclic sesquiterpene lactones (SL), costunolide and santonin. Using established protocols, we studied two cocaine-induced behavioral effects in planaria; the induction of motility decrease and the induction of C-like hyperkinesia. Cocaine, parthenolide, costunolide, santonin, and a lactone-less cyclic sesquiterpene, beta-eudesmol, decreased planarian motility in a concentration-dependent manner. Only cocaine induced C-like hyperkinesia. At concentrations that did not show any motility decrease, parthenolide, costunolide and santonin, but not beta-eudesmol, significantly reduced the cocaine-induced motility decrease and C-like hyperkinesia, in a concentration-dependent manner. Furthermore, parthenolide, costunolide and santonin were able to rescue planaria from C-like hyperkinesia, after the worms were exposed to cocaine. Conversely, cocaine at a concentration that did not show any measurable effects (10 microM), was able to alleviate the SL-, but not the beta-eudesmol-induced motility decrease. Liquid Chromatography/Mass Spectrometry experiments demonstrated that cocaine does not interact directly with any of the cyclic sesquiterpenoids, which suggests specific biochemical targets for these compounds in planarians. Our data suggests a common binding site for cocaine and the sesquiterpene lactones in planarians.

  13. Heliolactone, a non-sesquiterpene lactone germination stimulant for root parasitic weeds from sunflower.

    PubMed

    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.

  14. Effects of alpha-tocopherol on lactones in beef headspace during storage.

    PubMed

    Watanabe, A; Imanari, M; Higuchi, M; Shiba, N; Yonai, M

    2010-01-01

    We studied the effect of alpha-tocopherol (alpha-Toc) on the production of lactones, a desirable flavor in Wagyu beef (Japanese Black Cattle), in meat headspace. Fresh beef was minced and divided into 4 groups containing different alpha-Toc levels (1.9, 2.7, 6.1, and 10.7 mg/kg) or packed with oxygen absorber. After 10 d of storage at 2 °C, these samples were cooked in distilled water and rendered fat was collected. The headspace of the fat was analyzed with solid-phase microextraction combined with gas chromatography-mass spectrometry. The DB-17MS capillary column led to good separation of aliphatic lactones. Oxygen was important for the development of all lactones during storage. The amounts of gamma-octalactone and gamma-nonalactone decreased linearly with increasing alpha-Toc levels. The effect of alpha-Toc on delta-decalactone, delta-undecalactone, and delta-tetoradecalactone was weaker, and that on delta-hexadecalactone was ambiguous. These observations suggest that oxidation was necessary to develop the flavor of Wagyu beef, and warn that an excessive increase of alpha-Toc could reduce levels of positive flavor components, gamma-octalactone and gamma-nonalactone, in the headspace of Wagyu beef.

  15. Short Chain N-Acylhomoserine Lactone Production by Clinical Multidrug Resistant Klebsiella pneumoniae Strain CSG20

    PubMed Central

    Ngeow, Yun Fong; Cheng, Huey Jia; Chen, Jian Woon; Yin, Wai-Fong; Chan, Kok-Gan

    2013-01-01

    Klebsiella pneumoniae is one of the most common Gram-negative bacterial pathogens in clinical practice. It is associated with a wide range of disorders, ranging from superficial skin and soft tissue infections to potentially fatal sepsis in the lungs and blood stream. Quorum sensing, or bacterial cell-cell communication, refers to population density-dependent gene expression modulation. Quorum sensing in Proteobacteria relies on the production and sensing of signaling molecules which are mostly N-acylhomoserine lactones. Here, we report the identification of a multidrug resistant clinical isolate, K. pneumoniae strain CSG20, using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. We further confirmed quorum sensing activity in this strain with the use of high resolution tandem liquid chromatography quadrupole mass spectrometry and provided evidence K. pneumoniae strain CSG20 produced N-hexanoyl-homoserine lactone (C6-HSL). To the best of our knowledge, this is the first report on the production of N-hexanoylhomoserine lactone (C6-HSL) in clinical isolate K. pneumoniae. PMID:24284772

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    PubMed Central

    Yin, Wai-Fong; Purmal, Kathiravan; Chin, Shenyang; Chan, Xin-Yue; Koh, Chong-Lek; Sam, Choon-Kook; Chan, Kok-Gan

    2012-01-01

    Bacteria communicate by producing quorum sensing molecules called autoinducers, which include autoinducer-1, an N-hexanoyl homoserine lactone (AHL), and autoinducer-2. Bacteria present in the human oral cavity have been shown to produce autoinducer-2, but not AHL. Here, we report the isolation of two AHL-producing Klebsiella pneumoniae strains from the posterior dorsal surface of the tongue of a healthy individual. Spent culture supernatant extracts from K. pneumoniae activated the biosensors Agrobacterium tumefaciens NTL4(pZLR4) and Escherichia coli [pSB401], suggesting the presence of both long and short chain AHLs. High resolution mass spectrometry analyses of these extracts confirmed that both K. pneumoniae isolates produced N-octanoylhomoserine lactone and N-3-dodecanoyl-l-homoserine lactone. To the best of our knowledge, this is the first report of the isolation of K. pneumoniae from the posterior dorsal surface of the human tongue and the production of these AHLs by this bacterium. PMID:22737019

  18. Hepatocurative potential of sesquiterpene lactones of Taraxacum officinale on carbon tetrachloride induced liver toxicity in mice.

    PubMed

    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.

  19. Interconvertions between delta-lactam and delta-lactone derivatives initiated by unique transannular interactions of the rigid cyclohexane boat structure in pentacycloundecane.

    PubMed

    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.

  20. Lovastatin lactone elicits human lung cancer cell apoptosis via a COX-2/PPARγ-dependent pathway

    PubMed Central

    Ramer, Robert; Mittag, Nadine; Hinz, Burkhard

    2016-01-01

    Statins (3-hydroxy-3-methylglutaryl coenzyme A [HMG-CoA] reductase inhibitors) are well-established agents to treat hyperlipidemic states. Experimental and epidemiological evidence further implies an anticancer effect of these substances. This study investigates the mechanism underlying human lung cancer cell death by lovastatin and the role of the prostaglandin (PG)-synthesizing enzyme cyclooxygenase-2 (COX-2) in this process. In A549 and H358 lung carcinoma cells the lipophilic prodrug lovastatin lactone led to a concentration-dependent decrease of viability and induction of DNA fragmentation, whereas its HMG-CoA-inhibitory, ring-open acid form was inactive in this respect. Apoptotic cell death by lovastatin was accompanied by high intracellular levels of the lactone form, by upregulation of COX-2 mRNA and protein, as well as by increased formation of peroxisome proliferator-activated receptor γ (PPARγ)-activating PGD2 and 15-deoxy-Δ12,14-PGJ2. Cells were significantly less sensitive to lovastatin-induced apoptotic cell death, when the expression or activity of COX-2 was suppressed by siRNA or by the COX-2 inhibitor NS-398. Apoptosis by lovastatin was likewise reversed by the PPARγ antagonist GW9662. Fluorescence microscopy analyses revealed a lovastatin-induced cytosol-to-nucleus translocation of PPARγ that was inhibited by NS-398. Collectively, this study demonstrates COX-2 induction and subsequent COX-2-dependent activation of PPARγ as a hitherto unknown mechanism by which lovastatin lactone induces human lung cancer cell death. PMID:26863638

  1. Quorum sensing inhibitory potential and molecular docking studies of sesquiterpene lactones from Vernonia blumeoides.

    PubMed

    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

  2. Operon for Biosynthesis of Lipstatin, the Beta-Lactone Inhibitor of Human Pancreatic Lipase

    PubMed Central

    Bai, Tingli; Zhang, Daozhong; Lin, Shuangjun; Long, Qingshan; Wang, Yemin; Ou, Hongyu; Kang, Qianjin; Deng, Zixin; Liu, Wen

    2014-01-01

    Lipstatin, isolated from Streptomyces toxytricini as a potent and selective inhibitor of human pancreatic lipase, is a precursor for tetrahydrolipstatin (also known as orlistat, Xenical, and Alli), the only FDA-approved antiobesity medication for long-term use. Lipstatin features a 2-hexyl-3,5-dihydroxy-7,10-hexadecadienoic-β-lactone structure with an N-formyl-l-leucine group attached as an ester to the 5-hydroxy group. It has been suggested that the α-branched 3,5-dihydroxy fatty acid β-lactone moiety of lipstatin in S. toxytricini is derived from Claisen condensation between two fatty acid substrates, which are derived from incomplete oxidative degradation of linoleic acid based on feeding experiments. In this study, we identified a six-gene operon (lst) that was essential for the biosynthesis of lipstatin by large-deletion, complementation, and single-gene knockout experiments. lstA, lstB, and lstC, which encode two β-ketoacyl–acyl carrier protein synthase III homologues and an acyl coenzyme A (acyl-CoA) synthetase homologue, were indicated to be responsible for the generation of the α-branched 3,5-dihydroxy fatty acid backbone. Subsequently, the nonribosomal peptide synthetase (NRPS) gene lstE and the putative formyltransferase gene lstF were involved in decoration of the α-branched 3,5-dihydroxy fatty acid chain with an N-formylated leucine residue. Finally, the 3β-hydroxysteroid dehydrogenase-homologous gene lstD might be responsible for the reduction of the β-keto group of the biosynthetic intermediate, thereby facilitating the formation of the unique β-lactone ring. PMID:25239907

  3. Formation of macrocyclic lactones in the Paternò-Büchi dimerization reaction.

    PubMed

    Arimura, Junya; Mizuta, Tsutomu; Hiraga, Yoshikazu; Abe, Manabu

    2011-02-28

    Furan-2-ylmethyl 2-oxoacetates 1a,b, in which the furan ring and the carbonyl moiety were embedded intramolecularly, were synthesized from commercially available furan-2-ylmethanol and their photochemical reaction (hν > 290 nm) was investigated. Twelve-membered macrocyclic lactones 2a,b with C(i) symmetry including two oxetane-rings, which are the Paternò-Büchi dimerization products, were isolated in ca. 20% yield. The intramolecular cyclization products, such as 3-alkoxyoxetane and 2,7-dioxabicyclo[2.2.1]hept-5-ene derivatives, were not detected in the photolysate.

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

    PubMed

    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.

  5. Origin of Kinetic Resolution of Hydroxy Esters through Catalytic Enantioselective Lactonization by Chiral Phosphoric Acids.

    PubMed

    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.

  6. Amphids: the neuronal ultrastructure of macrocyclic-lactone-resistant Haemonchus contortus.

    PubMed

    Guerrero, J; Freeman, A S

    2004-06-01

    The development of anthelmintic resistance by nematode parasites is a growing problem for veterinarians and producers. The intensive use of the macrocyclic lactones for the treatment of a variety of parasitic diseases has hastened the development of resistance to this family of parasiticides among sheep, goats and cattle. As a result, resistance to ivermectin, moxidectin and doramectin by Haemonchus contortus has been documented throughout the world. While the exact sites of action of the macrocyclic lactones remain incompletely known, a critical point of entry for these drugs may be the terminally exposed sensory major neurons located in the cephalic end of the worms. These neurons, called amphidial neurons, are located in a pair of channels, the amphids, on either side of the pharynx and are exposed to the external environment via pores at the anterior tip of the worm. Through these neurons, important chemical and thermal cues are gathered by the parasite. Examination of serial electron micrographs of ivermectin-susceptible and ivermectin-resistant H. contortus allows for comparison of neuronal structure, arrangement of neurons within the amphidial channel, and distance of the tip of the dendritic processes to the amphidial pore. The latter of these characteristics provides a useful means by which to compare the association between the neurons and the external environment of the worm. Comparison of parental laboratory strains of ivermectin-susceptible H. contortus with related selected, ivermectin-resistant strains and with a wild-type ivermectin-susceptible field strain of H. contortus from Louisiana reveals that the ivermectin-resistant worms examined have markedly shorter sensory cilia than their ivermectin-susceptible parental counterparts. Additionally, the amphidial neurons of ivermectin-resistant worms are characterized by generalized degeneration and loss of detail, whereas other neurons outside of the channels, such as the labial and cephalic neurons

  7. Lupane triterpenes with a δ-lactone at ring E, from Lippia mexicana.

    PubMed

    Maldonado, Emma; Díaz-Arumir, Humberto; Toscano, R Alfredo; Martínez, Mahinda

    2010-11-29

    Three new lupane-type triterpenes, lippiolide (1), lippiolidolic acid (2), and lippiolic acid (3), were isolated from aerial parts of Lippia mexicana. Compounds 1 and 2 exhibited a δ-lactone at ring E. The known cycloartane triterpene 5 was also isolated. The structures of these compounds were established on the basis of spectroscopic data and chemical reactions, and the structure of compound 1 was confirmed by X-ray diffraction analysis. Anti-inflammatory activity of compounds 1, 3, and 5 was evaluated in the TPA-induced ear mouse edema model. Lupanes 1 and 3 were more active than cycloartane 5.

  8. Synergistic insecticidal mode of action between sesquiterpene lactones and a phototoxin, alpha-terthienyl.

    PubMed

    Guillet, G; Harmatha, J; Waddell, T G; Philogène, B J; Arnason, J T

    2000-02-01

    The synergistic insecticidal action of characteristic defensive substances produced by the plant family Asteraceae was investigated under controlled laboratory conditions. Sesquiterpene lactones isolated from Asteraceae that may form, through a Michael addition process, conjugates with glutathione were administered in a meridic diet to a herbivorous insect, Manduca sexta. By administering sesquiterpenes, variable in vivo reduced glutathione levels were observed in the insect larvae. When the Asteraceae-derived photooxidant alpha-terthienyl was co-administered, lipid peroxidation and larval mortality were significantly enhanced in the treated groups of insects with lowered in vivo glutathione levels.

  9. Recent studies on the zoopharmacognosy, pharmacology and neurotoxicology of sesquiterpene lactones.

    PubMed

    Robles, M; Aregullin, M; West, J; Rodriguez, E

    1995-06-01

    Aspects of recent research on the biological activities of sesquiterpene lactones (SQLs) are presented. Several SQLs have been identified as important constituents of plants consumed by animals for presumed medicinal value and is a focus of research in zoopharmacognosy. Recent in vivo antitumor studies with parthenin and eupatoriopicrin are discussed as well as the reports of the antiulcer activity of dehydroleucodin. Helenalin has recently been reported to have cardiotonic activity. Research on the neurotoxicity of repin, a compound reported to cause a Parkinson's-like disease in horses, is also highlighted.

  10. Regio- and Stereoselective Functionalization of 16-Membered Lactone Aglycone of Spiramycin via Cascade Strategy.

    PubMed

    Klich, Katarzyna; Pyta, Krystian; Przybylski, Piotr

    2015-07-17

    Functionalization of 16-membered aglycone of spiramycin with the use of intramolecular cascade strategy yielded access to novel types of diastereopure bicyclic spiramycin derivatives containing tetrahydrofuran ring. Experimental results shows that a specific sequence of regio- and stereoselective transformations, based on the intramolecular transesterification, E1cB tandem eliminations, 1,2-addition to carbonyl, and 1,6-conjugate addition at the spiramycin aglycone, proceeds with the inversion of absolute configuration at C(5) stereogenic center. Performed cascade and multistep transformations have opened new possibilities in divergent modifications, not only spiramycin but also the whole family of leucomycin type antibiotics having a similar structure of 16-membered aglycone lactone ring.

  11. Catalytic Asymmetric Synthesis of 3-Hydroxy-3-trifluoromethyl Benzofuranones via Tandem Friedel-Crafts/Lactonization Reaction.

    PubMed

    Ren, Hai; Wang, Pan; Wang, Lijia; Tang, Yong

    2015-10-02

    A highly enantioselective and regioselective chiral Lewis acid catalyzed tandem Friedel-Crafts/lactonization reaction is reported, providing direct access to plenty of 3-hydroxy-3-trifluoromethyl benzofuran-2-ones in up to 94% yields with up to >99% ee. Mechanistic study reveals that the interactions between the phenolic hydroxyl group and trifluoropyruvate are the most likely contributing factor to the high enantio- and regioselectivity. Optically pure (-)-BHFF can be obtained in gram-scale with 0.05 mol % catalyst, demonstrating the potentially utility of this method in medicinal chemistry.

  12. Facilitating Cytokine-Mediated Cancer Cell Death by Proteobacterial N-Acylhomoserine Lactones

    PubMed Central

    Kravchenko, Vladimir; Garner, Amanda L.; Mathison, John; Seit-Nebi, Alim; Yu, Jing; Gileva, Irina P.; Ulevitch, Richard; Janda, Kim D.

    2013-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) preferentially induces apoptosis in cancer cells over normal cells; however, tumor cells may develop TRAIL resistance. Here we demonstrate that this resistance can be overcome in the presence of bacterial acylhomoserine lactones (AHLs) or AHL-producing bacteria through the combined effect of TRAIL-induced apoptosis and AHL-mediated inhibition of inflammation regulated by NF-κB signaling. This discovery unveils a previously unrecognized symbiotic link between bacteria and host immunosurveillance. PMID:23517377

  13. The impact of sesquiterpene lactones and phenolics on sensory attributes: An investigation of a curly endive and escarole germplasm collection.

    PubMed

    Filippo D'Antuono, L; Ferioli, Federico; Manco, Manuela Agata

    2016-05-15

    In the present study, curly endive (Cichorium endivia L. var. crispum) and escarole (Cichorium endivia L. var. latifolium) accessions were investigated for their sensory characters (bitterness, astringency and herbaceous flavour) and acceptance in relation to sesquiterpene lactone and phenolic content. Different facets of the perception of these sensory traits in relation to lactones and phenolics were brought out. Lactucopicrin and kaempferol malonyl glucoside were consistently related to bitterness, astringency and herbaceous flavour perceptions. Overall acceptance was significantly and inversely related mainly to bitterness. The generic statement that sesquiterpene lactones and phenolic compounds are determinants of bitterness and other related sensory characters does not seem to be fully consistent with our data, that indicated how the balance of different compounds affects these traits individually, in a rather complex manner, with a prevailing negative impact of phenolics. Bitter, astringent, and herbaceous perceptions were significantly affected by variety, with curly endive showing on average higher scores in comparison to escarole, with particular respect to bitterness.

  14. Acyl-homoserine lactones from Erwinia psidii R. IBSBF 435T, a guava phytopathogen (Psidium guajava L.).

    PubMed

    Pomini, Armando M; Manfio, Gilson P; Araújo, Welington L; Marsaioli, Anita J

    2005-08-10

    The phytopathogen Erwinia psidii R. IBSBF 435T causes rot in branches, flowers, and fruits of guava (Psidium guajava L.), being responsible for crop losses, and has no effective control. It was demonstrated that this strain produces two compounds [S-(-)-N-hexanoyl and N-heptanoyl-homoserine lactone], both belonging to the class of quorum-sensing signaling substances. A protocol using gas chromatography-flame ionization detection with chiral stationary phase is described for the absolute configuration determination of a natural acyl-homoserine lactone. Biological assays with specific reporter and synthesis of identified substances are also described. This is the first report on the N-heptanoyl-homoserine lactone occurrence in the Erwinia genus.

  15. Immunomodulation and the quorum sensing molecule 3-oxo-C12-homoserine lactone: The importance of chemical scaffolding for probe development†

    PubMed Central

    Garner, Amanda L.; Yu, Jing; Struss, Anjali K.; Kaufmann, Gunnar F.

    2013-01-01

    As a guide for chemical probe design, focused analogue synthetic studies were undertaken upon the lactone ring of 3-oxo-C12-homoserine lactone. We have concluded that hydrolytic instability of the heterocyclic ring is pivotal for its ability to modulate immune signaling and probe preparation was aligned with these findings. PMID:23328974

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

    PubMed

    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.

  17. Lovastatin lactone may improve irritable bowel syndrome with constipation (IBS-C) by inhibiting enzymes in the archaeal methanogenesis pathway

    PubMed Central

    Muskal, Steven M.; Sliman, Joe; Kokai-Kun, John; Pimentel, Mark; Wacher, Vince; Gottlieb, Klaus

    2016-01-01

    Methane produced by the methanoarchaeon Methanobrevibacter smithii ( M. smithii) has been linked to constipation, irritable bowel syndrome with constipation (IBS-C), and obesity. Lovastatin, which demonstrates a cholesterol-lowering effect by the inhibition of HMG-CoA reductase, may also have an anti-methanogenesis effect through direct inhibition of enzymes in the archaeal methanogenesis pathway. We conducted protein-ligand docking experiments to evaluate this possibility. Results are consistent with recent clinical findings. METHODS: F420-dependent methylenetetrahydromethanopterin dehydrogenase ( mtd), a key methanogenesis enzyme was modeled for two different methanogenic archaea: M. smithii and Methanopyrus kandleri. Once protein models were developed, ligand-binding sites were identified. Multiple ligands and their respective protonation, isomeric and tautomeric representations were docked into each site, including F420-coenzyme (natural ligand), lactone and β-hydroxyacid forms of lovastatin and simvastatin, and other co-complexed ligands found in related crystal structures. RESULTS: 1) Generally, for each modeled site the lactone form of the statins had more favorable site interactions compared to F420; 2) The statin lactone forms generally had the most favorable docking scores, even relative to the native template PDB ligands; and 3) The statin β-hydroxyacid forms had less favorable docking scores, typically scoring in the middle with some of the F420 tautomeric forms. Consistent with these computational results were those from a recent phase II clinical trial ( NCT02495623) with a proprietary, modified-release lovastatin-lactone (SYN-010) in patients with IBS-C, which showed a reduction in symptoms and breath methane levels, compared to placebo. CONCLUSION: The lactone form of lovastatin exhibits preferential binding over the native-F420 coenzyme ligand in silico and thus could inhibit the activity of the key M. smithii methanogenesis enzyme mtd in vivo

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

    PubMed Central

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

    2016-01-01

    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. PMID:27420072

  19. [Preparation of hydrophilic matrix sustained release tablets of total lactones from Andrographis paniculata and study on its in vitro release mechanism].

    PubMed

    Xu, Fang-Fang; Shi, Wei; Zhang, Hui; Guo, Qing-Ming; Wang Zhen-Zhong; Bi, Yu-An; Wang, Zhi-Min; Xiao, Wei

    2015-01-01

    In this study, hydrophilic matrix sustained release tablets of total lactones from Andrographis paniculata were prepared and the in vitro release behavior were also evaluated. The optimal prescription was achieved by studying the main factor of the type and amount of hydroxypropyl methylcellulose (HPMC) using single factor test and evaluating through cumulative release of three lactones. No burst drug release from the obtained matrix tablets was observed. Drug release sustained to 14 h. The release mechanism of three lactones from A. paniculata was accessed by zero-order, first-order, Higuchi and Peppas equation. The release behavior of total lactones from A. paniculata was better agreed with Higuchi model and the drug release from the tablets was controlled by degradation of the matrix. The preparation of hydrophilic matrix sustained release tablets of total lactones from A. paniculata with good performance of drug release was simple.

  20. Ostalactones A-C, β- and ε-Lactones with Lipase Inhibitory Activity from the Cultured Basidiomycete Stereum ostrea.

    PubMed

    Kang, Hahk-Soo; Kim, Jong-Pyung

    2016-12-23

    Ostalactones A-C (1-3), three new β- and ε-lactone natural products, were isolated from the culture broth of the basidiomycete Stereum ostrea. The structures were elucidated by interpretation of HRFABMS and 1D and 2D NMR data. The structures of 1 and 2 are characterized by the presence of a β-lactone containing a fused 4/5 bicyclic core structure. Compound 3 possesses a 2-oxepinone ring system, which is likely to be a biosynthetic precursor of compounds 1 and 2. Ostalactones A (1) and B (2) displayed potent inhibitory activity against human pancreatic lipase.

  1. New macrocyclic lactones with acaricidal and nematocidal activities from a genetically engineered strain Streptomyces bingchenggensis BCJ60.

    PubMed

    Li, Jian-Song; Zhang, Hui; Zhang, Shao-Yong; Wang, Hai-Yan; Zhang, Ji; Chen, An-Liang; Wang, Ji-Dong; Xiang, Wen-Sheng

    2017-04-01

    Two new macrocyclic lactones, 4,25-diethyl-4,25-demethyl-milbemycin β3 (1) and 27-formaldehyde-milbemycin β14 (2), were isolated from a genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were determined on the basis of spectroscopic analysis, including 1D and 2D NMR techniques as well as ESI-MS and comparison with data from the literature. The acaricidal and nematocidal capacities of compounds 1 and 2 were evaluated against Tetranychus cinnabarinus and Bursaphelenchus xylophilus, respectively. The results showed that the two new macrocyclic lactones 1 and 2 possessed potent acaricidal and nematocidal activities.

  2. Utilization of a 1,2-dioxine for the synthesis of the four possible stereoisomers of oak lactone.

    PubMed

    Brown, Rachel C; Taylor, Dennis K; Elsey, Gordon M

    2006-02-02

    [reaction: see text]. The natural products cis- and trans-oak lactone (1) have been prepared, along with their enantiomeric counterparts, from furanone 12, which was itself prepared from racemic 1,2-dioxine 9 and a chiral malonate diester. The key steps in the synthesis of 1 are the use of the malonate diester as a chromatographic resolving agent and the decarboxylation of 13, which can be directed to give either the cis- or trans-product. This leads to all four possible oak lactone stereoisomers from a common intermediate.

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

    PubMed

    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.

  4. Metal-Free Synthesis of N-Aryl Amides using Organocatalytic Ring-Opening Aminolysis of Lactones.

    PubMed

    Guo, Wusheng; Gómez, José Enrique; Martínez-Rodríguez, Luis; Bandeira, Nuno A G; Bo, Carles; Kleij, Arjan W

    2017-04-05

    Catalytic ring-opening of bio-sourced non-strained lactones with aromatic amines can offer a straightforward, 100 % atom-economical, and sustainable pathway towards relevant N-aryl amide scaffolds. Herein, the first general, metal-free, and highly efficient N-aryl amide formation is reported from poorly reactive aromatic amines and non-strained lactones under mild operating conditions using an organic bicyclic guanidine catalyst. This protocol has high application potential as exemplified by the formal syntheses of drug-relevant molecules.

  5. Generation of cell-to-cell signals in quorum sensing: acyl homoserine lactone synthase activity of a purified Vibrio fischeri LuxI protein.

    PubMed

    Schaefer, A L; Val, D L; Hanzelka, B L; Cronan, J E; Greenberg, E P

    1996-09-03

    Many bacteria use acyl homoserine lactone signals to monitor cell density in a type of gene regulation termed quorum sensing and response. Synthesis of these signals is directed by homologs of the luxi gene of Vibrio fischeri. This communication resolves two critical issues concerning the synthesis of the V. fischeri signal. (i) The luxI product is directly involved in signal synthesis-the protein is an acyl homoserine lactone synthase; and (ii) the substrates for acyl homoserine lactone synthesis are not amino acids from biosynthetic pathways or fatty acid degradation products, but rather they are S-adenosylmethionine (SAM) and an acylated acyl carrier protein (ACP) from the fatty acid biosynthesis pathway. We purified a maltose binding protein-LuxI fusion polypeptide and showed that, when provided with the appropriate substrates, it catalyzes the synthesis of an acyl homoserine lactone. In V. fischeri, luxi directs the synthesis of N-(3-oxohexanoyl) homoserine lactone and hexanoyl homoserine lactone. The purified maltose binding protein-LuxI fusion protein catalyzes the synthesis of hexanoyl homoserine lactone from hexanoyl-ACP and SAM. There is a high level of specificity for hexanoyl-ACP over ACPs with differing acyl group lengths, and hexanoyl homoserine lactone was not synthesized when SAM was replaced with other amino acids, such as methionine, S-adenosylhomocysteine, homoserine, or homoserine lactone, or when hexanoyl-SAM was provided as the substrate. This provides direct evidence that the LuxI protein is an auto-inducer synthase that catalyzes the formation of an amide bond between SAM and a fatty acyl-ACP and then catalyzes the formation of the acyl homoserine lactone from the acyl-SAM intermediate.

  6. Effect of dehydrocostus lactone and costunolide from Saussurea root on the central nervous system in mice.

    PubMed

    Okugawa, H; Ueda, R; Matsumoto, K; Kawanishi, K; Kato, A

    1996-09-01

    Saussurea root (Mokko in Japanese; root of Saussurea lappa, Compositae) is an aromatic stomachic and sedative in Oriental medicine. Four extracts of saussurea root were obtained by successively extracting with benzene, chloroform, methanol and water. Each of these extracts was tested for effects on the central nervous system (CNS) of mice by intraperitoneal administration, i. e. potentiation of hexobarbital sleeping time, body temperature alterations, antinociceptive effects, and spontaneous locomotor activity changes. The benzene extract was the most active and was then separated further into five fractions, 1,2,3,4, and 5 by column chromatography. Fraction 2 was shown to be the most active in the aforementioned assays. From this fraction dehydrocostus lactone and costunolide were isolated as the CNS active constituents. They were both active by the intraperitoneal, intragastric and intracerebroventricular routes of administration. They decreased both methamphetamine- and apomorphine-induced spontaneous motility. The level of homovanillic acid in the brain was increased following their administration, while the levels of monoamines and other metabolites were unchanged. Similar results were seen in chlorpromazine-treated mice. These results show that dehydrocostus lactone and costunolide can be considered as neuroleptics by resemblance of their pharmacological activities to chlorpromazine.

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

    PubMed

    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.

  8. New allo-cedrane type sesquiterpene hemiketals and further sesquiterpene lactones from fruits of Illicium floridanum.

    PubMed

    Schmidt, T J; Müller, E; Fronczek, F R

    2001-04-01

    Three new tetracyclic sesquiterpene hemiketals possessing the very rare allo-cedrane carbon skeleton, debenzoyl-7-deoxo-1 alpha,7 alpha-dihydroxytashironin, debenzoyl-7-deoxo-7 alpha-hydroxytashironin, and debenzoyl-7-deoxo-7 alpha-hydroxy-3-oxotashironin (1--3), were isolated from the fruits of Illicium floridanum ELLIS (American Star Anise, Star bush). Their structures were elucidated by mass and NMR spectroscopic analyses. The molecular structure of 1, including absolute stereochemistry, was determined by single-crystal X-ray diffraction of its monohydrate. Only one compound of this type, tashironin, has previously been isolated from Illicium tashiroi. Furthermore, a new sesquiterpene lactone of the seco-prezizaane type, 3,4-anhydro-13,14-dihydroxyfloridanolide (4), and the known anislactone B (5) were isolated. The occurrence of further allo-cedrane sesquiterpenes in another Illicium species confirms the hypothesis of previous authors that this type of compound is a biogenetic precursor of the typical seco-prezizaane sesquiterpene lactones found in this genus. Moreover, regarding their co-occurrence with anislactone B as reported here, they may also be considered precursors for the anislactone skeletal type.

  9. Chemical and Biological Investigation of Olive Mill Waste Water - OMWW Secoiridoid Lactones.

    PubMed

    Vougogiannopoulou, Konstantina; Angelopoulou, Maria T; Pratsinis, Harris; Grougnet, Raphaël; Halabalaki, Maria; Kletsas, Dimitris; Deguin, Brigitte; Skaltsounis, Leandros A

    2015-08-01

    Olive mill waste water is the major byproduct of the olive oil industry containing a range of compounds related to Olea europaea and olive oil constituents. Olive mill waste water comprises an important environmental problem in olive oil producing countries, but it is also a valuable material for the isolation of high added value compounds. In this study, an attempt to investigate the secoiridoid content of olive mill waste water is described with the aid of ultrahigh-performance liquid chromatography-electrospray ionization (±)-high-resolution mass spectrometry and centrifugal partition chromatography methods. In total, seven secoiridoid lactones were isolated, four of which are new natural products. This is the first time that a conjugate of hydroxytyrosol and a secoiridoid lactone has been isolated from olive mill waste water and structurally characterized. Furthermore, the range of isolated compounds allowed for the proposal of a hypothesis for the biotransformation of olive secoiridoids during the production of olive mill waste water. Finally, the ability of the representative compounds to reduce the intracellular reactive oxygen species was assessed with the dichlorofluorescein assay in conjunction with the known antioxidant agent hydroxytyrosol.

  10. Pressure-Induced Polymerization of Carbon Monoxide: Disproportionation and Synthesis of an Energetic Lactonic Polymer

    SciTech Connect

    Evans, W.J.; Lipp, M.J.; Yoo, C.-S.; Cynn, H.; Herberg, J.L.; Maxwell, R.S.; Nicol, M.F.

    2008-10-02

    We have studied pressure-induced chemical reactions in carbon monoxide using both a diamond anvil cell and a modified large volume press. Our spectroscopic data reveal that carbon monoxide disproportionates into molecular CO{sub 2} and a solid lactone-type polymer; photochemically above 3.2 GPa, thermochemically above 5 GPa at 300 K, or at 3 GPa and {approx}2000 K as achieved by laser heating. The solid product can be recovered at ambient conditions with a high degree of conversion, measured to be up to 95% of the original CO. Its fundamental chemical structure includes {beta}-lactone and conjugated C=C, which can be considered a severely modified polymeric carbon suboxide with open ladders and smaller five-membered rings. The polymer is metastable at ambient conditions, spontaneously liberating CO{sub 2} gases exothermically. We find that the recovered polymer has a high energy density, 1-8 kJ/g, and is very combustible. We estimate the density of recovered CO polymer to be at least 1.65 g/cm{sup 3}.

  11. Synthesis and analysis of thio-, thiono-, and dithio-derivatives of whiskey lactone.

    PubMed

    Schmarr, H G; Eisenreich, W; Engel, K H

    2001-12-01

    Cis- and trans-3-methyl-4-octanolide (1, whiskey lactones) were converted into their thio- (2), thiono- (3), and dithio- (4) derivatives by reaction with phosphorus pentasulfide. The reaction products were characterized by GC-mass spectrometry, (1)H NMR spectroscopy, and GC-olfactometry. Two-dimensional NOESY spectra showed that sulfur is incorporated into the ring with reversal of the absolute configuration at C-4, whereas substitution of the keto-oxygen atom by sulfur occurs with retention of ring configuration. The cis- and trans-pairs of 2, 3, and 4 were separated into enantiomers by GC on heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin and heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as chiral stationary phases. GC-olfactometry revealed a sweet coconut-like odor for the cis-thio- and pleasant mushroom-like flavors for the cis-thiono- and trans-dithio-derivatives of whiskey lactone.

  12. Novel Reporter for Identification of Interference with Acyl Homoserine Lactone and Autoinducer-2 Quorum Sensing

    PubMed Central

    Weiland-Bräuer, Nancy; Pinnow, Nicole

    2014-01-01

    Two reporter strains were established to identify novel biomolecules interfering with bacterial communication (quorum sensing [QS]). The basic design of these Escherichia coli-based systems comprises a gene encoding a lethal protein fused to promoters induced in the presence of QS signal molecules. Consequently, these E. coli strains are unable to grow in the presence of the respective QS signal molecules unless a nontoxic QS-interfering compound is present. The first reporter strain designed to detect autoinducer-2 (AI-2)-interfering activities (AI2-QQ.1) contained the E. coli ccdB lethal gene under the control of the E. coli lsrA promoter. The second reporter strain (AI1-QQ.1) contained the Vibrio fischeri luxI promoter fused to the ccdB gene to detect interference with acyl-homoserine lactones. Bacteria isolated from the surfaces of several marine eukarya were screened for quorum-quenching (QQ) activities using the established reporter systems AI1-QQ.1 and AI2-QQ.1. Out of 34 isolates, two interfered with acylated homoserine lactone (AHL) signaling, five interfered with AI-2 QS signaling, and 10 were demonstrated to interfere with both signal molecules. Open reading frames (ORFs) conferring QQ activity were identified for three selected isolates (Photobacterium sp., Pseudoalteromonas sp., and Vibrio parahaemolyticus). Evaluation of the respective heterologously expressed and purified QQ proteins confirmed their ability to interfere with the AHL and AI-2 signaling processes. PMID:25527543

  13. Chemopreventive activity of sesquiterpene lactones (SLs) from yacon against TPA-induced Raji cells deformation.

    PubMed

    Siriwan, D; Miyawaki, C; Miyamoto, T; Naruse, T; Okazaki, K; Tamura, H

    2011-05-15

    Yacon is a medicinal plant used as a traditional medicine by the natives in South America. In Japan, it becomes popular as a health food. Sesquiterpene Lactones (SLs) from yacon leaves were investigated and the active SLs such as enhydrin, uvedalin and sonchifolin, bearing alpha-methylene-gamma-lactone and epoxides as the active functional groups, were identified by 1H-6000 MHz-NMR. Chemopreventive and cytotoxic activities were determined using different primary screening methods. In this study, all tested SLs strongly inhibited TPA-induced deformed of Raji cells. The IC50 values of yacon SLs from anti-deforming assay were 0.04-0.4 microM. Interestingly, yacon SLs showed more potential of chemo preventive activity than both curcumin and parthenolide. However, the cytotoxicity on Raji cells was observed at high concentration of yacon SLs. The degree of anti-deformation was ranked in order: enhydrin >uvedalin >sonchifolin >parthenolide >curcumin. As according to structure-activity relationship, the high activities of enhydrin, uvedalin and sonchifolin may be due to the 2-methyl-2-butenoate and its epoxide moiety.

  14. Microbial homoserine lactones (AHLs) are effectors of root morphological changes in barley.

    PubMed

    Rankl, Simone; Gunsé, Benet; Sieper, Tina; Schmid, Christoph; Poschenrieder, Charlotte; Schröder, Peter

    2016-12-01

    While colonizing the rhizosphere, bacterial intra- and inter-specific communication is accomplished by N-Acyl-homoserine-lactones (AHLs) in a density-dependent manner. Moreover, plants are naturally exposed to AHLs and respond with tissue-specificity. In the present study, we investigated the influence of N-hexanoyl- (C6-HSL), N-octanoyl- (C8-HSL) and N-dodecanoyl-d/l-homoserine lactone (C12-HSL) on growth and root development in barley (Hordeum vulgare L.), and identified initial reactions in root cells after AHL exposures using physiological, staining, and electrophysiological methods. Treatment with short- and long-chain AHLs modulated plant growth and branched root architecture and induced nitric oxide (NO) accumulation in the calyptra and root elongation zone of excised roots in an AHL derivative-independent way. Additionally, C6- and C8-HSL treatments stimulated K(+) uptake in root cells only at certain concentrations, whereas all tested concentrations of C12-HSL induced K(+) uptake. In further experiments, C8-HSL promoted membrane hyperpolarization in epidermal root cells. Thus, we conclude AHLs promote plant growth and lateral root formation, and cause NO accumulation as an early response to AHLs. Furthermore, the AHL-mediated membrane hyperpolarization is leading to increased K(+) uptake of the root tissue.

  15. Pressure-induced polymerization of carbon monoxide: disproportionation and synthesis of an energetic lactonic polymer

    SciTech Connect

    Evans, W J; Lipp, M J; Yoo, C; Herberg, J L; Maxwell, R S; Nicol, M F

    2005-10-04

    We have studied pressure-induced chemical reactions in carbon monoxide using both a diamond-anvil cell and a modified large volume press. Our spectroscopic data reveal that carbon monoxide disproportionates into molecular CO{sub 2} and a solid lactone-type polymer; photochemically above 3.2 GPa, thermochemically above 5 GPa at 300K, or at 3 GPa and {approx}2000K as achieved by laser heating. The solid product can be recovered at ambient conditions with a high degree of conversion, measured to be up to 95% of the original CO. Its fundamental chemical structure includes {beta}-lactone and conjugated C=C, which can be considered a severely modified polymeric carbon suboxide with open ladders and smaller five-membered rings. The polymer is metastable at ambient conditions, spontaneously liberating CO{sub 2} gases exothermically. We find that the recovered polymer has a high energy density, 1-8 KJ/g, and is very combustible. We estimate the density of recovered CO polymer to be at least 1.65 g/cm cm{sup 3}.

  16. A sesquiterpene lactone from Siegesbeckia glabrescens suppresses Hedgehog/Gli-mediated transcription in pancreatic cancer cells

    PubMed Central

    Lee, Hwa Jin; Wu, Qian; Li, Hua; Bae, Gyu-Un; Kim, An Keun; Ryu, Jae-Ha

    2016-01-01

    Pancreatic cancer is aggressive and therefore difficult to treat; however, continued efforts have been made with the aim of developing an effective therapy against the disease. The Hedgehog (Hh) signaling pathway is reportedly involved in the proliferation and survival of pancreatic cancer cells. The transcription factor glioma-associated oncogene (Gli) is a key component of the Hh signaling pathway and the primary effector of pancreatic cancer development. Inhibiting Gli is a proven therapeutic strategy for this disease. The present study examined the regulation of Gli and the expression of its target genes to identify an inhibitor of the Sonic Hh (Shh) pathway. A germacranolide sesquiterpene lactone (GSL) was isolated from Siegesbeckia glabrescens as an inhibitor of Gli-mediated transcription. The results demonstrated that GSL inhibited Shh-induced osteoblast differentiation and Gli homolog 1 (Gli1)-mediated transcriptional activity in mesenchymal C3H10T1/2 stem cells. Furthermore, GSL suppressed Gli-mediated transcriptional activity in human pancreatic cancer PANC-1 and AsPC-1 cells, which resulted in reduced cancer cell proliferation and downregulated expression of the Gli-target genes, Gli1 and cyclin D1. A sesquiterpene lactone from S. glabrescens may therefore serve as a candidate for the treatment of Hh/Gli-dependent pancreatic cancer. PMID:27698879

  17. Metabolism of Acyl-Homoserine Lactone Quorum-Sensing Signals by Variovorax paradoxus

    PubMed Central

    Leadbetter, Jared R.; Greenberg, E. P.

    2000-01-01

    Acyl-homoserine lactones (acyl-HSLs) serve as dedicated cell-to-cell signaling molecules in many species of the class Proteobacteria. We have addressed the question of whether these compounds can be degraded biologically. A motile, rod-shaped bacterium was isolated from soil based upon its ability to utilize N-(3-oxohexanoyl)-l-homoserine lactone as the sole source of energy and nitrogen. The bacterium was classified as a strain of Variovorax paradoxus. The V. paradoxus isolate was capable of growth on all of the acyl-HSLs tested. The molar growth yields correlated with the length of the acyl group. HSL, a product of acyl-HSL metabolism, was used as a nitrogen source, but not as an energy source. Cleavage and partial mineralization of the HSL ring were demonstrated by using radiolabeled substrate. This study indicates that some strains of V. paradoxus degrade and grow on acyl-HSL signals as the sole energy and nitrogen sources. This study provides clues about the metabolic pathway of acyl-HSL degradation by V. paradoxus. PMID:11092851

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

    PubMed

    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.

  19. Metabolism of acyl-homoserine lactone quorum-sensing signals by Variovorax paradoxus.

    PubMed

    Leadbetter, J R; Greenberg, E P

    2000-12-01

    Acyl-homoserine lactones (acyl-HSLs) serve as dedicated cell-to-cell signaling molecules in many species of the class Proteobacteria. We have addressed the question of whether these compounds can be degraded biologically. A motile, rod-shaped bacterium was isolated from soil based upon its ability to utilize N-(3-oxohexanoyl)-L-homoserine lactone as the sole source of energy and nitrogen. The bacterium was classified as a strain of Variovorax paradoxus. The V. paradoxus isolate was capable of growth on all of the acyl-HSLs tested. The molar growth yields correlated with the length of the acyl group. HSL, a product of acyl-HSL metabolism, was used as a nitrogen source, but not as an energy source. Cleavage and partial mineralization of the HSL ring were demonstrated by using radiolabeled substrate. This study indicates that some strains of V. paradoxus degrade and grow on acyl-HSL signals as the sole energy and nitrogen sources. This study provides clues about the metabolic pathway of acyl-HSL degradation by V. paradoxus.

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

    PubMed

    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.

  1. Metabolism of 4-chloro-2-methylphenoxyacetate by a soil pseudomonad. Ring-fission, lactonizing and delactonizing enzymes.

    PubMed

    Gaunt, J K; Evans, W C

    1971-05-01

    1. A cell-free system, prepared from Pseudomonas N.C.I.B. 9340 grown on 4-chloro-2-methylphenoxyacetate (MCPA) was shown to catalyse the reaction sequence: 5-chloro-3-methylcatechol --> cis-cis-gamma-chloro-alpha-methylmuconate --> gamma-carboxymethylene-alpha-methyl-Delta(alphabeta)-butenolide --> gamma-hydroxy-alpha-methylmuconate. 2. The activity of the three enzymes involved in these reactions was completely resolved and the lactonizing and delactonizing enzymes were separated. 3. This part of the metabolic pathway of 4-chloro-2-methylphenoxyacetate is thus confirmed for this bacterium. 4. The ring-fission oxygenase required Fe(2+) or Fe(3+) and reduced glutathione for activity; the lactonizing enzyme is stimulated by Mn(2+), Mg(2+), Co(2+) and Fe(2+); no cofactor requirement could be demonstrated for the delactonizing enzyme. 5. cis-cis-gamma-Chloro-alpha-methylmuconic acid was isolated and found to be somewhat unstable, readily lactonizing to gamma-carboxymethylene-alpha-methyl-Delta(alphabeta)-butenolide. 6. Enzymically the lactonization appears to be a single-step dehydrochlorinase reaction.

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

    PubMed

    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. Effect of costunolide and dehydrocostus lactone on cell cycle, apoptosis, and ABC transporter expression in human soft tissue sarcoma cells.

    PubMed

    Kretschmer, Nadine; Rinner, Beate; Stuendl, Nicole; Kaltenegger, Heike; Wolf, Elisabeth; Kunert, Olaf; Boechzelt, Herbert; Leithner, Andreas; Bauer, Rudolf; Lohberger, Birgit

    2012-11-01

    Human soft tissue sarcomas represent a rare group of malignant tumours that frequently exhibit chemotherapeutic resistance and increased metastatic potential following unsuccessful treatment. In this study, we investigated the effects of costunolide and dehydrocostus lactone, which have been isolated from Saussurea lappa using activity-guided isolation, on three soft tissue sarcoma cell lines of various origins. The effects on cell proliferation, cell cycle distribution, apoptosis induction, and ABC transporter expression were analysed. Both compounds inhibited cell viability dose- and time-dependently. IC50 values ranged from 6.2 µg/mL to 9.8 µg/mL. Cells treated with costunolide showed no changes in cell cycle, little in caspase 3/7 activity, and low levels of cleaved caspase-3 after 24 and 48 h. Dehydrocostus lactone caused a significant reduction of cells in the G1 phase and an increase of cells in the S and G2/M phase. Moreover, it led to enhanced caspase 3/7 activity, cleaved caspase-3, and cleaved PARP indicating apoptosis induction. In addition, the influence of costunolide and dehydrocostus lactone on the expression of ATP binding cassette transporters related to multidrug resistance (ABCB1/MDR1, ABCC1/MRP1, and ABCG2/BCRP1) was examined using real-time RT-PCR. The expressions of ABCB1/MDR1 and ABCG2/BCRP1 in liposarcoma and synovial sarcoma cells were significantly downregulated by dehydrocostus lactone. Our data demonstrate for the first time that dehydrocostus lactone affects cell viability, cell cycle distribution and ABC transporter expression in soft tissue sarcoma cell lines. Furthermore, it led to caspase 3/7 activity as well as caspase-3 and PARP cleavage, which are indicators of apoptosis. Therefore, this compound may be a promising lead candidate for the development of therapeutic agents against drug-resistant tumours.

  4. Use of cyclodextrins as solubilizing agents for simvastatin: effect of hydroxypropyl-β-cyclodextrin on lactone/hydroxyacid aqueous equilibrium.

    PubMed

    Ungaro, Francesca; Giovino, Concetta; Catanzano, Ovidio; Miro, Agnese; Mele, Andrea; Quaglia, Fabiana; La Rotonda, Maria Immacolata

    2011-02-14

    The chemical conversion of simvastatin from the lactone (SVL) to the hydroxyacid (SVA) form is becoming an intriguing issue associated with the pharmacological use of SVL. On this matter, recent findings suggest that SVL complexation with cyclodextrins (CDs) may be a useful strategy to affect its aqueous solubility and chemical stability. In this work, a reverse-phase high-performance liquid chromatography (RP-HPLC) method able to selectively identify and quantify SVL and SVA has been set up, validated and applied to follow SVL hydrolysis in the presence of HPβCD. The combination of stability results with simvastatin/HPβCD stability constants achieved from UV-vis measurements and solubility/dissolution studies allowed to get an insight into SVL/HPβCD, SVA/HPβCD and SVL/SVA equilibria taking place in aqueous solution. Results show that in the presence of HPβCD the aqueous SVL/SVA equilibrium is shifted versus the hydroxyacid form. UV-vis results, showing that the lactone and the open-ring form of simvastatin interact with HPβCD in a similar extent, suggest that hydrolysis occurs also on SVL/HPβCD complex, thus supporting a mode of interaction that does not involve the lactone ring. This hypothesis is strengthened by NMR analysis performed on SVA, HPβCD and their inclusion complex, which indicates that the lactone ring is not included in HPβCD hydrophobic cavity. Finally, results suggest that particular attention must be paid to SVL lactonization in aqueous solution when using CD-based formulations and in demonstrating their effective benefit for a specific therapeutic use.

  5. Chemoenzymatic Synthesis of trans-β-Aryl-δ-hydroxy-γ-lactones and Enzymatic Kinetic Resolution of Their Racemic Mixtures.

    PubMed

    Skrobiszewski, Andrzej; Gładkowski, Witold; Maciejewska, Gabriela; Wawrzeńczyk, Czesław

    2016-11-23

    Two novel and convenient routes to obtain enantiomerically enriched trans-β-aryl-δ-hydroxy-γ-lactones 5a-d with potential antifeedant and anticancer activity were developed. In the first method starting from corresponding enantiomers of γ,δ-unsaturated esters 4a-d derived from enzymatically resolved allyl alcohols 1a-d, both enantiomers of hydroxylactones 5a-d were synthesized with high enantiomeric excesses (73%-97%). Configurations of the stereogenic centers of the synthesized compounds were assigned based on the mechanism of acidic lactonization of esters 4a-d in the presence of m-chloroperbenzoic acid (m-CPBA). An alternative method for the production of optically active trans-β-aryl-δ-hydroxy-γ-lactones 5a-d was lipase-catalyzed kinetic resolution of their racemic mixtures by transesterification with vinyl propionate as the acyl donor. The most efficient enzyme in the screening procedure was lipase B from Candida antarctica. Its application on a preparative scale after 6 h afforded unreacted (+)-(4S,5R,6S)-hydroxylactones 5a-d and (+)-(4R,5S,6R)-propionates 6a-d, most of them with high enantiomeric excesses (92%-98%). Resolution of lactone 5d with bulky 1,3-benzodioxol ring provided products with significantly lower optical purity (ee = 89% and 84% for hydroxylactone 5d and propionate 6d, respectively). The elaborated methods give access to both enantiomers of trans-β-aryl-δ-hydroxy-γ-lactones 5a-d with the defined absolute configurations of stereogenic centers, which is crucial requirement for the investigations of relationship: spatial structure-biological activity.

  6. Synthesis of histidinoalanine: a comparison of β-lactone and sulfamidate electrophiles.

    PubMed

    Taylor, Carol M; De Silva, Samanthi Thabrew

    2011-07-15

    Previous syntheses of histidinoalanine (HAL) have led to mixtures of regioisomers and/or stereoisomers. For example, opening of N-Cbz-D-serine-β-lactone (6) with Boc-L-His-OMe (5) gave a 2:1 mixture of τ- and π-regioisomers. The sulfamidate 10, derived from N-benzyl-D-serine methyl ester (11), was reacted with Boc-L-His-OMe (5) to give the τ-HAL derivative 17 as a single isomer in 57% yield. A similarly prepared τ-HAL 19, bearing protecting groups that were all hydrogenolytically labile, led to the free bis-amino acid, τ-L-histidinyl-D-alanine (τ-4), as a salt-free standard for amino acid analysis.

  7. Extraction, purification and identification of bacterial signal molecules based on N‐acyl homoserine lactones

    PubMed Central

    Wang, Jianhua; Quan, Chunshan; Wang, Xue; Zhao, Pengchao; Fan, Shengdi

    2011-01-01

    Summary Bacteria possess an extraordinary repertoire for intercellular communication and social behaviour. This repertoire for bacterial communication, termed as quorum sensing (QS), depends on specific diffusible signal molecules. There are many different kinds of signal molecules in the bacterial community. Among those signal molecules, N‐acyl homoserine lactones (HSLs, in other publications also referred to as AHLs, acy‐HSLs etc.) are often employed as QS signal molecules for many Gram‐negative bacteria. Due to the specific structure and tiny amount of those HSL signal molecules, the characterization of HSLs has been the subject of extensive investigations in the last decades and has become a paradigm for bacteria intercellular signalling. In this article, different methods, including extraction, purification and characterization of HSLs, are reviewed. The review provides an insight into identification and characterization of new HSLs and other signal molecules for bacterial intercellular communication. PMID:21375695

  8. Costunolide, a sesquiterpene lactone from Saussurea lappa, inhibits the VEGFR KDR/Flk-1 signaling pathway.

    PubMed

    Jeong, Sei-Joon; Itokawa, Takashi; Shibuya, Masabumi; Kuwano, Michihiko; Ono, Mayumi; Higuchi, Ryuichi; Miyamoto, Tomofumi

    2002-12-10

    Costunolide (CT), a sesquiterpene lactone constituent isolated from Saussurea lappa (Compositae), exerted an antiangiogenic effect. CT selectively inhibited the endothelial cell proliferation induced by vascular endothelial growth factor (VEGF). Further, CT was also found to inhibit the VEGF-induced chemotaxis of human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner. From these results, we hypothesized that CT might inhibit angiogenesis by blocking the angiogenic factor signaling pathway. VEGF interacts with its cognate receptors, KDR/Flk-1 and Flt-1, and exerts its angiogenic effect. CT inhibited the autophosphorylation of KDR/Flk-1 without affecting that of Flt-1. Moreover, administration of CT reduced VEGF-induced neovascularization in a mouse corneal micropocket assay. These results suggest that CT may prove useful for the development of a novel angiogenesis inhibitor.

  9. Inhibition of Wnt/β-Catenin Pathway by Dehydrocostus Lactone and Costunolide in Colon Cancer Cells.

    PubMed

    Dong, Guang-Zhi; Shim, Ah-Ram; Hyeon, Jin Seong; Lee, Hwa Jin; Ryu, Jae-Ha

    2015-05-01

    Abnormal activation of β-catenin has been reported in 90% in the sporadic and hereditary colorectal cancer. The suppression of abnormally activated β-catenin is one of the good strategies for chemoprevention and treatment of colorectal cancer. In this study, we have isolated two main compounds from root of Saussurea lappa, dehydrocostus lactone (DCL) and costunolide (CL), and investigated their anti-colorectal cancer activities. DCL and CL suppressed cyclin D1 and survivin through inhibiting nuclear translocation of β-catenin. They also suppressed the nuclear translocation of galectin-3 that is one of the coactivators of β-catenin in SW-480 colon cancer cells. Furthermore, DCL and CL suppressed proliferation and survival of SW-480 colon cancer cells through the induction of cell cycle arrest and cell death. Taken together, DCL and CL from root of S. lappa have anti-colorectal cancer activities through inhibiting Wnt/β-catenin pathway.

  10. A new sesquiterpene lactone from the roots of Saussurea lappa: structure-anticancer activity study.

    PubMed

    Robinson, A; Kumar, T Vijay; Sreedhar, E; Naidu, V G M; Krishna, Sistla Rama; Babu, K Suresh; Srinivas, P V; Rao, J Madhusudana

    2008-07-15

    The dried roots of Saussurea lappa, called costus roots, are used in the traditional system of medicine for the treatment of cancer. In our investigation for the anticancer constituents from the hexane extract of this plant, a new sesquiterpene (1) was isolated along with the known compounds costunolide (2), beta-cyclocostunolide (3), dihydro costunolide (4) and dehydro costuslactone (5). Their structures were established by the extensive spectroscopic analyses. In addition, costunolide and beta-cyclocostunolide derivatives were synthesized using Michael-type addition reaction of NaOMe to the alpha-methylene-gamma-lactone moiety. All the compounds were tested for their in vitro cytotoxic activity. Compound 1 exhibited potent cytotoxic activity and other compounds displayed moderate activity.

  11. Synthesis and Biological Evaluation of Several Bryostatin Analogues Bearing a Diacylglycerol Lactone C-Ring.

    PubMed

    Baumann, David O; McGowan, Kevin M; Kedei, Noemi; Peach, Megan L; Blumberg, Peter M; Keck, Gary E

    2016-09-02

    As an initial step in designing a simplified bryostatin hybrid molecule, three bryostatin analogues bearing a diacylglycerol lactone-based C-ring, which possessed the requisite pharmacophores for binding to protein kinase C (PKC) together with a modified bryostatin-like A- and B-ring region, were synthesized and evaluated. Merle 46 and Merle 47 exhibited binding affinity to PKC alpha with Ki values of 7000 ± 990 and 4940 ± 470 nM, respectively. Reinstallation of the trans-olefin and gem-dimethyl group present in bryostatin 1 in Merle 48 resulted in improved binding affinity, 363 ± 42 nM. While Merle 46 and 47 were only marginally active biologically, Merle 48 showed sufficient activity on the U937 cells to confirm that it was PMA-like for growth and attachment, as predicted by the substitution pattern of its A- and B-rings.

  12. Stereospecific Cross-Coupling Reactions of Aryl-Substituted Tetrahydrofurans, Tetrahydropyrans, and Lactones

    PubMed Central

    2015-01-01

    The stereospecific ring-opening of O-heterocycles to provide acyclic alcohols and carboxylic acids with controlled formation of a new C–C bond is reported. These reactions provide new methods for synthesis of acyclic polyketide analogs with complex stereochemical arrays. Stereoselective synthesis of the cyclic template is utilized to control relative configuration; subsequent stereospecific nickel-catalyzed ring-opening affords the acyclic product. Aryl-substituted tetrahydrofurans and tetrahydropyrans undergo nickel-catalyzed Kumada-type coupling with a range of Grignard reagents to furnish acyclic alcohols with high diastereoselectivity. Enantioenriched lactones undergo Negishi-type cross-coupling with dimethylzinc to afford enantioenriched carboxylic acids. Application in a two-step enantioselective synthesis of an anti-dyslipidemia agent is demonstrated. PMID:25308512

  13. Biosynthetic studies on the botcinolide skeleton: new hydroxylated lactones from Botrytis cinerea.

    PubMed

    Reino, José L; Durán-Patrón, Rosa M; Daoubi, Mourad; Collado, Isidro G; Hernández-Galán, Rosario

    2006-01-20

    [reaction: see text] The biosynthetic origin of the botcinolide skeleton was investigated by means of feeding 13C- and 2H-labeled precursors to Botrytis cinerea. Three new compounds, two homobotcinolide derivatives, 3-O-acetylhomobotcinolide (5) and 8-methylhomobotcinolide (6), and a new 11-membered lactone (7), were isolated. Their structures were elucidated on the basis of spectroscopic data, including one-bond and long-range 1H-13C correlations. The relative stereochemistries were determined by combined analyses of NOE data and 1H-1H coupling constants. According to the results of feeding experiments with 13C- and 2H-labeled acetate and l-S-methylmethionine, 5 is an acetate-derived polyketide whose methyl groups originate from l-S-methylmethionine. This is a rare example of the incorporation of a methyl from methionine into a supposed C3 starter unit of the polyketide synthesis.

  14. Staphylococcus intermedius Produces a Functional agr Autoinducing Peptide Containing a Cyclic Lactone

    PubMed Central

    Ji, Guangyong; Pei, Wuhong; Zhang, Linsheng; Qiu, Rongde; Lin, Jianqun; Benito, Yvonne; Lina, Gerard; Novick, Richard P.

    2005-01-01

    The agr system is a global regulator of accessory functions in staphylococci, including genes encoding exoproteins involved in virulence. The agr locus contains a two-component signal transduction module that is activated by an autoinducing peptide (AIP) encoded within the agr locus and is conserved throughout the genus. The AIP has an unusual partially cyclic structure that is essential for function and that, in all but one case, involves an internal thiolactone bond between a conserved cysteine and the C-terminal carboxyl group. The exceptional case is a strain of Staphylococcus intermedius that has a serine in place of the conserved cysteine. We demonstrate here that the S. intermedius AIP is processed by the S. intermedius AgrB protein to generate a cyclic lactone, that it is an autoinducer as well as a cross-inhibitor, and that all of five other S. intermedius strains examined also produce serine-containing AIPs. PMID:15838041

  15. Short Chain N-Acyl Homoserine Lactone Production in Tropical Marine Vibrio sinaloensis Strain T47

    PubMed Central

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

    2014-01-01

    Quorum sensing (QS), acts as one of the gene regulatory systems that allow bacteria to regulate their physiological activities by sensing the population density with synchronization of the signaling molecules that they produce. Here, we report a marine isolate, namely strain T47, and its unique AHL profile. Strain T47 was identified using 16S rRNA sequence analysis confirming that it is a member of Vibrio closely clustered to Vibrio sinaloensis. The isolated V. sinaloensis strain T47 was confirmed to produce N-butanoyl-L-homoserine lactone (C4-HSL) by using high resolution liquid chromatography tandem mass spectrometry. V. sinaloensis strain T47 also formed biofilms and its biofilm formation could be affected by anti-QS compound (cathechin) suggesting this is a QS-regulated trait in V. sinaloensis strain T47. To our knowledge, this is the first documentation of AHL and biofilm production in V. sinaloensis strain T47. PMID:25046018

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

    PubMed

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

    2014-11-01

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

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

    PubMed Central

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

    2014-01-01

    The implementation of beneficial microorganisms for plant protection has a long history. Many rhizobia bacteria are able to influence the immune system of host plants by inducing resistance towards pathogenic microorganisms. In this report, we present a translational approach in which we demonstrate the resistance-inducing effect of Ensifer meliloti (Sinorhizobium meliloti) on crop plants that have a significant impact on the worldwide economy and on human nutrition. Ensifer meliloti is usually associated with root nodulation in legumes and nitrogen fixation. Here, we suggest that the ability of S. meliloti to induce resistance depends on the production of the quorum-sensing molecule, oxo-C14-HSL. The capacity to enhanced resistance provides a possibility to the use these beneficial bacteria in agriculture. Using the Arabidopsis-Salmonella model, we also demonstrate that the application of N-acyl-homoserine lactones-producing bacteria could be a successful strategy to prevent plant-originated infections with human pathogens. PMID:25234390

  18. Inhibiting N-acyl-homoserine lactone synthesis and quenching Pseudomonas quinolone quorum sensing to attenuate virulence

    PubMed Central

    Chan, Kok-Gan; Liu, Yi-Chia; Chang, Chien-Yi

    2015-01-01

    Bacteria sense their own population size, tune the expression of responding genes, and behave accordingly to environmental stimuli by secreting signaling molecules. This phenomenon is termed as quorum sensing (QS). By exogenously manipulating the signal transduction bacterial population behaviors could be controlled, which may be done through quorum quenching (QQ). QS related regulatory networks have been proven their involvement in regulating many virulence determinants in pathogenic bacteria in the course of infections. Interfering with QS signaling system could be a novel strategy against bacterial infections and therefore requires more understanding of their fundamental mechanisms. Here we review the development of studies specifically on the inhibition of production of N-acyl-homoserine lactone (AHL), a common proteobacterial QS signal. The opportunistic pathogen, Pseudomonas aeruginosa, equips the alkylquinolone (AQ)-mediated QS which also plays crucial roles in its pathogenicity. The studies in QQ targeting on AQ are also discussed. PMID:26539190

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

    Seo, Chang-Seob; Shin, Hyeun-Kyoo

    2015-01-01

    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. PMID:26246732

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

    PubMed

    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.

  2. 1,2-dioxines as masked cis gamma-hydroxy enones and their versatility in the synthesis of highly substituted gamma-lactones.

    PubMed

    Greatrex, Ben W; Kimber, Marc C; Taylor, Dennis K; Fallon, Gary; Tiekink, Edward R T

    2002-07-26

    Addition of highly stabilized ester nucleophiles to 1,2-dioxines affords good to high yields of gamma-lactones with high diastereoselectivity. Heterolytic or homolytic cleavage of the 1,2-dioxines under appropriate conditions generates the key reactive cis gamma-hydroxy enones, which ultimately afford the observed gamma-lactones. Diastereoselectivity is installed as a result of anti 1,4-addition by the ester enolate to the cis enones followed by intramolecular cyclization. The reaction is tolerant of a range of substitution patterns on the 1,2-dioxine while a broad range of esters are also accommodated. In addition to the synthesis of racemic gamma-lactones, highly enantioenriched gamma-lactones can also be synthesized when chiral cobalt(II) catalysts are employed for the initial homolytic ring-opening of the 1,2-dioxine.

  3. 1,5-asymmetric induction of chirality using pi-allyltricarbonyliron lactone complexes: highly diastereoselective synthesis of alpha-functionalised carbonyl compounds.

    PubMed

    Hollowood, Christopher J; Ley, Steven V; Wright, Edward A

    2003-09-21

    Silyl enol ethers derived from ketone functionalised rho-allyltricarbonyliron lactone complexes undergo highly diastereoselective carbon-fluorine and carbon-oxygen bond formation reactions with excellent control at the alpha-stereogenic centre.

  4. Preparation of an eight-membered sesquiterpene lactone resulting from sequential Gif System GoAgg(III) and MCPBA oxidation of (+)-10beta,14-dihydroxy-allo-aromadendrane.

    PubMed

    de Bodas, Márcia M L; Marques, Maria Rita; Beatriz, Adilson; de Lima, Dênis P

    2005-08-31

    Studies aimed at a comparison of chemical, biomimetic (Gif system GoAgg(III))and enzymatic (CHMO) transformations of natural (+)-10beta,14-dihydroxy-allo-aromadendrane have led to preparation of an eight-member sesquiterpene lactone.

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

    PubMed

    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).

  6. The alpha-methylene-gamma-butyrolactone moiety in dehydrocostus lactone is responsible for cytoprotective heme oxygenase-1 expression through activation of the nuclear factor E2-related factor 2 in HepG2 cells.

    PubMed

    Jeong, Gil-Saeng; Pae, Hyun-Ock; Jeong, Sun-Oh; Kim, Youn-Chul; Kwon, Tae-Oh; Lee, Ho Sub; Kim, Nam-Song; Park, Seok Don; Chung, Hun-Taeg

    2007-06-22

    Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a major role in the pathogenesis of several diseases. The alpha-methylene-gamma-butyrolactone (CH2-BL) structural unit, which characterizes a group of naturally occurring sesquiterpene lactones, is known to possess numerous biological activities. In the present study, we evaluated dehydrocostus lactone possessing CH2-BL moiety, one of the bioactive constituents of the medicinal plant Saussurea lappa, as an inducer of cytoprotective HO-1. In HepG2 cells, treatment with dehydrocostus lactone induced HO-1 expression and increased HO activity in a concentration-dependent manner. Similar results were also observed when the cells were incubated with CH2-BL, a parent structure of dehydrocostus lactone. In contrast, mokko lactone, a reduced product of dehydrocostus lactone, and alpha-methyl-gamma-butyrolactone (CH3-BL), a parent structure of mokko lactone, did not induce HO-1 expression. Pretreatment with either dehydrocostus lactone or CH2-BL for 6 h protected the cells from hydrogen peroxide-mediated toxicity, whereas mokko lactone or CH3-BL failed to exert a cytoprotective action. Inhibition of HO-1 expression by HO-1 small interfering RNA (siRNA) abrogated cellular protection afforded by dehydrocostus lactone or CH2-BL. In addition, dehydrocostus lactone caused the nuclear accumulation of the nuclear factor E2-related factor 2 (Nrf2) and increased the promoter activity of antioxidant response element (ARE). Using Nrf2 siRNA, Nrf2 activation was confirmed to contribute to cytoprotective HO-1 expression by dehydrocostus lactone or CH2-BL. Collectively, our findings suggest that CH2-BL moiety in dehydrocostus lactone increases cellular resistance to oxidant injury in HepG2 cells, presumably through Nrf2/ARE-dependent HO-1 expression.

  7. Study on the conversion of three natural statins from lactone forms to their corresponding hydroxy acid forms and their determination in Pu-Erh tea.

    PubMed

    Yang, Deng-Jye; Hwang, Lucy Sun

    2006-06-30

    Conversions of statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, from lactone forms to their corresponding hydroxy acid form in 0.1 N NaOH or 0.05 N KOH (prepared with 25, 50, 75, 90% acetonitrile or methanol in water or 100% water) were evaluated. Results showed that lactone form statins could be transformed almost completely only in alkaline solutions prepared with 25 or 50% acetonitrile. In all methanolic alkaline solutions, lactone form statins could also be converted entirely, nevertheless, they would be further transformed to the methyl ester of the hydroxy acid form and the transformation increased as methanol rises. When lactone and hydroxy acid forms of statins were in methanol, ethyl acetate, 70% acetonitrile in water (with 0.5% acetic acid or no) for 0-48 h at room temperature or in 100 degrees C water for 0-2 h, lactone form statins were converted to their corresponding hydroxy acids, which were raised as time extends and the highest conversions of them were about 35% in 100 degrees C water and 70% acetonitrile, slightly transformed for lactone form statins in 70% acetonitrile (with 0.5% acetic acid) after 8 h, and the other treatments for all statins showed no significant changes. Interferences would be reduced efficiently when statins were extracted from Pu-Erh tea with methanol, ethyl acetate or 100 degrees C water followed by purifying through a C18 solid-phase extraction cartridge. Lovastatin was the only statin found in Pu-Erh tea and the highest content of it was found under ethyl acetate extraction. In ethyl acetate and methanol extracts, lovastatin existed merely as lactone form. The lowest content of lovastatin was found in the 100 degrees C water extract of Pu-Erh tea, however, both of lactone and hydroxy acid forms were found to exist in the extract.

  8. 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.

    PubMed

    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.

  9. Biocatalytic Lactone Generation in Genetically Engineered Escherichia coli and Identification of Products by Gas Chromatography-Mass Spectroscopy

    NASA Astrophysics Data System (ADS)

    Slawson, Chad; Stewart, Jon; Potter, Robert

    2001-11-01

    Genetically altered Escherichia coli are used as biocatalysts to produce optically pure lactones from a variety of cyclic ketones as a biotechnology experiment for a biochemistry laboratory. The genetically engineered E. coli bacteria express large amounts of the enzyme cyclohexanone monooxygenase and are therefor capable of converting a variety of ketones into optically pure lactones. Separation by organic extraction and analysis by thin layer chromatography and gas chromatography-mass spectroscopy allows for the direct identification of products. Yield calculations and evaluation of the cost effectiveness of various substrates give students an opportunity to make recommendations and model industrial decision-making. Evaluation of the synthetic process for its environmental impact allows students to consider problems of cost versus environmental concerns. Use of bacterial biocatalysts offers chemistry students an opportunity to work with microorganisms and directly see the utility of genetically altered bacteria for synthetic chemistry.

  10. Catalytic Kinetic Resolution of a Dynamic Racemate: Highly Stereoselective β-Lactone Formation by N-Heterocyclic Carbene Catalysis

    PubMed Central

    Johnston, Ryne C.; Cohen, Daniel T.; Eichman, Chad C.

    2014-01-01

    This study describes the combined experimental and computational elucidation of the mechanism and origins of stereoselectivities in the NHC-catalyzed dynamic kinetic resolution (DKR) of α-substituted-β-ketoesters. Density functional theory computations reveal that the NHC-catalyzed DKR proceeds by two mechanisms, depending on the stereochemistry around the forming bond: 1) a concerted, asynchronous formal (2+2) aldol-lactonization process, or 2) a stepwise spiro-lactonization mechanism where the alkoxide is trapped by the NHC-catalyst. These mechanisms contrast significantly from mechanisms found and postulated in other related transformations. Conjugative stabilization of the electrophile and non-classical hydrogen bonds are key in controlling the stereoselectivity. This reaction constitutes an interesting class of DKRs in which the catalyst is responsible for the kinetic resolution to selectively and irreversibly capture an enantiomer of a substrate undergoing rapid racemization with the help of an exogenous base. PMID:25045464

  11. Glucuronic acid γ-lactone: an organic nonlinear optical crystal with high laser-induced damage threshold

    NASA Astrophysics Data System (ADS)

    Saripalli, Ravi Kiran; Bhat, Handady L.; Elizabeth, Suja

    2017-01-01

    Laser applications of nonlinear optical (NLO) crystals are limited by their laser damage threshold. We report a detailed study of the laser damage threshold of an NLO crystal glucuronic acid γ-lactone. Second-harmonic generation efficiency of glucuronic acid γ-lactone was estimated to be 3.5 times that of standard potassium dihydrogen phosphate. Conic sections due to spontaneous noncollinear phase matching were observed. Surface laser damage studies carried out for 1064-nm radiation on a (010) plate of the crystal yielded high-threshold values of 77.72±0.27 and 32.72±0.41 GW/cm2 for single- and multiple-shot damages, respectively. The possible mechanisms for the laser-induced damage are discussed.

  12. Experimental verification, and domain definition, of structural alerts for protein binding: epoxides, lactones, nitroso, nitros, aldehydes and ketones.

    PubMed

    Nelms, M D; Cronin, M T D; Schultz, T W; Enoch, S J

    2013-01-01

    This study outlines how a combination of in chemico and Tetrahymena pyriformis data can be used to define the applicability domain of selected structural alerts within the profilers of the OECD QSAR Toolbox. Thirty-three chemicals were profiled using the OECD and OASIS profilers, enabling the applicability domain of six structural alerts to be defined, the alerts being: epoxides, lactones, nitrosos, nitros, aldehydes and ketones. Analysis of the experimental data showed the applicability domains for the epoxide, nitroso, aldehyde and ketone structural alerts to be well defined. In contrast, the data showed the applicability domains for the lactone and nitro structural alerts needed modifying. The accurate definition of the applicability domain for structural alerts within in silico profilers is important due to their use in the chemical category in predictive and regulatory toxicology. This study highlights the importance of utilizing multiple profilers in category formation.

  13. Role of glycoconjugates of 3-methyl-4-hydroxyoctanoic acid in the evolution of oak lactone in wine during oak maturation.

    PubMed

    Wilkinson, Kerry L; Prida, Andrei; Hayasaka, Yoji

    2013-05-08

    Oak lactone is a natural component of oak wood, but it also exists in glycoconjugate precursor forms. This study concerned the role of glycoconjugates of 3-methyl-4-hydroxyoctanoic acid, specifically a galloylglucoside, glucoside, and rutinoside, in the evolution of oak lactone during cooperage and maturation. The glycoconjugate profiles of 10 French oak samples were obtained by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using stable isotope dilution analysis. The galloylglucoside was found to be the predominant glycoconjugate precursor and ranged in concentration from 110 to 354 μg/g. Maturation trials indicated the galloylglucoside undergoes acid-catalyzed hydrolysis after extraction into wine; after 12 months of maturation, the glucoside was the most abundant precursor, present at between 2- and 11-fold higher concentrations than those observed for powdered oak. Thermal degradation of glycoconjugates was observed only when oak samples were heated at 200 °C for 30 min, demonstrating their thermal stability.

  14. Organocatalytic Friedel-Crafts Alkylation/Lactonization Reaction of Naphthols with 3-Trifluoroethylidene Oxindoles: The Asymmetric Synthesis of Dihydrocoumarins.

    PubMed

    Zhao, Yun-Long; Lou, Qin-Xin; Wang, Long-Sheng; Hu, Wen-Hui; Zhao, Jun-Ling

    2017-01-02

    Naphthols and 3-trifluoroethylidene oxindoles were found to undergo an asymmetric Friedel-Crafts alkylation/lactonization reaction, catalyzed by only 2.5 mol % of a quinine-derived squaramide catalyst, to afford the corresponding α-aryl-β-trifluoromethyl dihydrocoumarin derivatives in high yields (up to 99 %) with excellent enantio- and diastereoselectivities (up to 98 % ee, >20:1 d.r.). Importantly, the lactonization proceeded by nucleophilic attack of the naphthol hydroxy group at the amide motif of the oxindoles under mild reaction conditions. This protocol represents a new strategy for the formation of dihydrocoumarins by an efficient intramolecular amide C-N bond-cleavage and esterification process.

  15. Production of acylated homoserine lactone by a novel marine strain of Proteus vulgaris and inhibition of its swarming by phytochemicals.

    PubMed

    Biswa, Pramal; Doble, Mukesh

    2014-10-01

    A marine strain of Proteus vulgaris capable of activating multiple acylated homoserine lactone (AHL)-based reporter cultures was isolated. The cognate signal molecule was characterized as octanoyl homoserine lactone (OHL) and its production was observed to be growth dependent, with maximum production (5.675 µg l(-1)) at 24 h growth. The strain exhibited swarming, but its motility was not affected upon addition of pure OHL or culture supernatant. Phytochemicals such as quercitin and berberine chloride inhibited OHL production and reduced swarming. FliA, the predominantly upregulated protein during swarming, was considered as a possible target for these inhibitors, and docking of the two most active and two least active inhibitors to this protein suggested preferential binding of the former set of compounds. Apart from adding new evidence to AHL production in Proteus vulgaris, active inhibitors shortlisted from this study could help in identifying lead compounds to act against this opportunistic pathogen of the respiratory and gastrointestinal tract.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

  19. Determination of lactones in wines by headspace solid-phase microextraction and gas chromatography coupled with mass spectrometry.

    PubMed

    Pérez-Olivero, S J; Pérez-Pont, M L; Conde, J E; Pérez-Trujillo, J P

    2014-01-01

    Application of headspace solid-phase microextraction (HS-SPME) coupled with high-resolution gas chromatographic (HRGC) analysis was studied for determining lactones in wines. Six different SPME fibers were tested, and the influence of different factors such as temperature and time of desorption, ionic strength, time of extraction, content of sugar, ethanol, tannins and anthocyanins, and pH and influence of SO2 were studied. The proposed HS-SPME-GC method is an appropriate technique for the quantitative analysis of γ-butyrolactone, γ-hexalactone, trans-whiskey lactone, γ-octalactone, cis-whiskey lactone, γ-nonalactone, γ-decalactone, δ-decalactone, and γ-undecalactone in wines. Method reproducibility and repeatability ranged between 0.6 and 5.2% for all compounds. Detection limit for γ-butyrolactone was 0.17 mg/L and a few μg/L for the rest of the compounds. The optimized method has been applied to several wine samples.

  20. Penicimenolides A-F, Resorcylic Acid Lactones from Penicillium sp., isolated from the Rhizosphere Soil of Panax notoginseng

    PubMed Central

    An, Ya-Nan; Zhang, Xue; Zhang, Tian-Yuan; Zhang, Meng-Yue; Qian-Zhang; Deng, Xiao-Yu; Zhao, Feng; Zhu, Ling-Juan; Wang, Guan; Zhang, Jie; Zhang, Yi-Xuan; Liu, Bo; Yao, Xin-Sheng

    2016-01-01

    Five new 12-membered resorcylic acid lactone derivatives, penicimenolides A-E (1–5), one new ring-opened resorcylic acid lactone derivative penicimenolide F (6), and six known biogenetically related derivatives (7–12) were isolated from the culture broth of a strain of Penicillium sp. (NO. SYP-F-7919), a fungus obtained from the rhizosphere soil of Panax notoginseng collected from the Yunnan province of China. Their structures were elucidated by extensive NMR analyses, a modified Mosher’s method, chemical derivatization and single crystal X-ray diffraction analysis. Compounds 2–4 exhibited potent cytotoxicity against the U937 and MCF-7 tumour cell lines and showed moderate cytotoxic activity against the SH-SY5Y and SW480 tumour cell lines. The substitution of an acetyloxy or 2-hydroxypropionyloxy group at C-7 significantly increased the cytotoxic activity of the resorcylic acid lactone derivatives. Subsequently, the possible mechanism of compound 2 against MCF-7 cells was preliminarily investigated by in silico analysis and experimental validation, indicating compound 2 may act as a potential MEK/ERK inhibitor. Moreover, proteomics analysis was performed to explore compound 2-regulated concrete mechanism underlying MEK/ERK pathway, which is still need further study in the future. In addition, compounds 2–4 and 7 exhibited a significant inhibitory effect on NO production induced by LPS. PMID:27271722

  1. Cytotoxic and apoptotic effects of leptocarpin, a plant-derived sesquiterpene lactone, on human cancer cell lines.

    PubMed

    Bosio, Claudia; Tomasoni, Giacomo; Martínez, Rolando; Olea, Andrés F; Carrasco, Héctor; Villena, Joan

    2015-12-05

    Sesquiterpene lactones have attracted much attention in drug research because they present a series of biological activities such as anticancer, antifungal, anti-inflammatory, antimicrobial and antioxidant. Leptocarpin (LTC) is a sesquiterpene lactone isolated from a native Chilean plant, Leptocarpha rivularis, which has been widely used in traditional medicine by Mapuche people. Previous work has demonstrated that LTC decreases cell viability of cancer cell lines. In this contribution, we analyze the mechanism of LTC cytotoxicity on different cancer cell lines. The results show that in all cases LTC induces an apoptotic process and inhibition of NF-κB. Apoptosis has been confirmed by observing condensation of chromatin, nuclear fragmentation, release of cytochrome c into the cytosol, and increasing of caspase-3 activity. It has also been found that LTC is an effective inhibitor of NF-κB, which suggests that leptocarpin-induced cytotoxicity involves in some degree the inhibition of NF-κB signaling pathway. The concentration at which LTC inhibits NF-κB activity to the control level is similar or even lower than that found for parthenolide and others sesquiterpene lactones. These results indicate that leptocarpine is a very interesting molecule that could be considered as therapeutic agent for cancer treatment.

  2. Characterisation of a marine bacterium Vibrio brasiliensis T33 producing N-acyl homoserine lactone quorum sensing molecules.

    PubMed

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

    2014-07-08

    N-acylhomoserine lactones (AHL) plays roles as signal molecules in quorum sensing (QS) in most Gram-negative bacteria. QS regulates various physiological activities in relation with population density and concentration of signal molecules. With the aim of isolating marine water-borne bacteria that possess QS properties, we report here the preliminary screening of marine bacteria for AHL production using Chromobacterium violaceum CV026 as the AHL biosensor. Strain T33 was isolated based on preliminary AHL screening and further identified by using 16S rDNA sequence analysis as a member of the genus Vibrio closely related to Vibrio brasiliensis. The isolated Vibrio sp. strain T33 was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL) and N-(3-oxodecanoyl)-L-homoserine lactone (3-oxo-C10 HSL) through high resolution tandem mass spectrometry analysis. We demonstrated that this isolate formed biofilms which could be inhibited by catechin. To the best of our knowledge, this is the first report that documents the production of these AHLs by Vibrio brasiliensis strain T33.

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

    PubMed Central

    Chen, Jian-Woon; Chin, Shenyang; Tee, Kok Keng; Yin, Wai-Fong; Choo, Yeun Mun; Chan, Kok-Gan

    2013-01-01

    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. PMID:24084113

  4. Determination of Lactones in Wines by Headspace Solid-Phase Microextraction and Gas Chromatography Coupled with Mass Spectrometry

    PubMed Central

    Pérez-Olivero, S. J.; Pérez-Pont, M. L.; Conde, J. E.; Pérez-Trujillo, J. P.

    2014-01-01

    Application of headspace solid-phase microextraction (HS-SPME) coupled with high-resolution gas chromatographic (HRGC) analysis was studied for determining lactones in wines. Six different SPME fibers were tested, and the influence of different factors such as temperature and time of desorption, ionic strength, time of extraction, content of sugar, ethanol, tannins and anthocyanins, and pH and influence of SO2 were studied. The proposed HS-SPME-GC method is an appropriate technique for the quantitative analysis of γ-butyrolactone, γ-hexalactone, trans-whiskey lactone, γ-octalactone, cis-whiskey lactone, γ-nonalactone, γ-decalactone, δ-decalactone, and γ-undecalactone in wines. Method reproducibility and repeatability ranged between 0.6 and 5.2% for all compounds. Detection limit for γ-butyrolactone was 0.17 mg/L and a few μg/L for the rest of the compounds. The optimized method has been applied to several wine samples. PMID:24782943

  5. Enantiospecific effect of pulegone and pulegone-derived lactones on Myzus persicae (Sulz.) settling and feeding.

    PubMed

    Dancewicz, Katarzyna; Gabrys, Beata; Dams, Iwona; Wawrzeńczyk, Czesław

    2008-04-01

    The effect of pulegone chiral center configuration on its antifeedant activity to Myzus persicae was examined. Biological consequences of structural modifications of (R)-(+)- and (S)-(-)-pulegone, the lactonization, iodolactonization, and incorporation of hydroxyl and carbonyl groups were studied, as well. The most active compounds were (R)-(+)-pulegone (1a) and delta-hydroxy-gamma-spirolactones (5S,6R,8S)-(-)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2-one (5b) and (5R,6S,8S)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2-one (6b) derived from (S)-(-)-pulegone (1b). The compounds deterred aphid probing and feeding at preingestional, ingestional, and postingestional phases of feeding. The preingestional effect of (R)-(+)-pulegone (1a) was manifested as difficulty in finding and reaching the phloem (i.e., prolonged time preceding the first contact with phloem vessels), a high proportion of probes not reaching beyond the mesophyll layer before first phloem phase, and/or failure to find sieve elements by 20% of aphids during the 8-hr experiment. The ingestional activity of (R)-(+)-pulegone (1a) and hydroxylactones 5b and 6b resulted in a decrease in duration of phloem sap ingestion, a decrease in the proportion of aphids with sustained sap ingestion, and an increase in the proportion of aphid salivation in phloem. delta-Keto-gamma-spirolactone (5R,8S)-(-)-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2,6-dione (8b) produced a weak ingestional effect (shortened phloem phase). The postingestional deterrence of (R)-(+)-pulegone (1a) and delta-hydroxy-gamma-spirolactones (5R,6S,8R)-(+)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]-decan-2-one (5a), 5b, (5S,6R,8R)-6-hydroxy-4,4,8-trimethyl-1-oxaspiro[4.5]decan-2-one (6a), 6b, and delta-keto-gamma-spirolactone 8b prevented aphids from settling on treated leaves. The trans position of methyl group CH3-8 and the bond C5-O1 in lactone 6b appeared to weaken the deterrent activity in relation to the cis diastereoisomer (5b).

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

    PubMed

    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.

  7. Localization of sesquiterpene lactone biosynthesis in cells of capitate glandular trichomes of Helianthus annuus (Asteraceae).

    PubMed

    Amrehn, Evelyn; Aschenbrenner, Anna-Katharina; Heller, Annerose; Spring, Otmar

    2016-03-01

    Capitate glandular trichomes (CGT) of sunflower, Helianthus annuus, synthesize bioactive sesquiterpene lactones (STLs) within a short period of only a few days during trichome development. In the current project, the subcellular localization of H. annuus germacrene A monooxygenase (HaGAO), a key enzyme of the STL biosynthesis in sunflower CGT, was investigated. A polyclonal antibody raised against this enzyme was used for immunolabelling. HaGAO was found in secretory and stalk cells of CGT. This correlated with the appearance of smooth endoplasmic reticulum in both cell types. Stalk cells and secretory cells differed in form, size and types of plastids, but both had structures necessary for secretion. No HaGAO-specific immunoreaction was found in sunflower leaf tissue outside of CGT or in developing CGT before the secretory phase had started. Our results indicated that not only secretory cells but also nearly all cells of the CGT were involved in the biosynthesis of STL and that this process was not linked to the presence or absence of a specific type of plastid.

  8. In vitro anti-inflammatory effects of cynaropicrin, a sesquiterpene lactone, from Saussurea lappa.

    PubMed

    Cho, J Y; Baik, K U; Jung, J H; Park, M H

    2000-06-23

    We investigated in vitro anti-inflammatory effects of cynaropicrin, a sesquiterpene lactone from Saussurea lappa, on tumor necrosis factor (TNF)-alpha and nitric oxide (NO) release, and lymphocyte proliferation. Cynaropicrin strongly inhibited TNF-alpha release from lipopolysaccharide-stimulated murine macrophage, RAW264.7 cells, and differentiated human macrophage, U937 cells, proved to produce notable amount of TNF-alpha. It also potently attenuated the accumulation of NO released from lipopolysaccharide- and interferon-gamma-stimulated RAW264.7 cells in a dose-dependent manner. In addition, the immunosuppressive effects of the compound on lymphocyte proliferation in response to mitogenic stimuli were examined. Cynaropicrin also dose-dependently suppressed the proliferation of lymphocytes from splenocytes and interleukin-2-sensitive cytotoxic T lymphocyte, CTLL-2 cells, stimulated by lipopolysaccharide, concanavalin A, phytohemagglutinin and interleukin-2. However, treatment with sulphydryl compound, L-cysteine, abrogated all these inhibitory effects. These results suggest that cynaropicrin may participate in the inflammatory response by inhibiting the production of inflammatory mediators and the proliferation of lymphocytes and its inhibitory effect is mediated through conjugation with sulphydryl groups of target protein(s).

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

    PubMed Central

    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. PMID:24106675

  10. Cytotoxic and ACAT-inhibitory sesquiterpene lactones from the root of Ixeris dentata forma albiflora.

    PubMed

    Ahn, Eun-Mi; Bang, Myun-Ho; Song, Myoung-Chong; Park, Mi-Hyun; Kim, Hwa-Young; Kwon, Byoung-Mog; Baek, Nam-In

    2006-11-01

    Ixeris dentata forma albiflora was extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and H2O. Eight sesquiterpenes were isolated through repeated silica gel and octadecyl silica gel (C18, ODS) column chromatography of the EtOAc and n-BuOH fractions. Physicochemical analysis using NMR, MS and IR revealed the chemical structures of the sesquiterpenes, which were zaluzanin (1), 9a-hydroxyguaian-4(15),10(14),11(13)-triene-6,12-olide (2), 3beta-O-beta-D-glucopyranosyl-8beta-hydroxyguaian-4(15),10(14)-diene-6,12-olide (3), 3-O-beta-D-glucopyranosyl-8beta-hydroxyguauan-10(14)-ene-6,12-olide (4), ixerin M (5), glucozaluzanin C (6), crepiside I (7), and ixerin D (8). This is the first time that these sesquiterpene lactones have been isolated from this plant. Compounds 1, 2 and 7 revealed relatively high cytotoxicities on human colon carcinoma cell and lung adenocarcinoma cell, while compounds 5 and 7 showed acyl-CoA: cholesterol acyltransferase (ACAT) inhibitory activity.

  11. New steroidal lactones and homomonoterpenic glucoside from fruits of Malva sylvestris L.

    PubMed

    Mustafa, Akhlaq; Ali, Mohammed

    2011-01-01

    Phytochemical investigation of the ethanolic extract of defatted fruits of Malva sylvestris Linn. (Malvaceae) led to the isolation of six new steroidal lactones and a homomonoterpenic glucoside along with beta-sitosterol-3-beta-D-glucopyranoside. The structures of new phytoconstituents have been elucidated as cholest-5-en-3a-ol-18(21)-olide (sylvestrosterol A), cholest-9(11)-en-3alpha-ol-18(21)-olide (sylvestrosterol B), cholest-4,6,22-trien-3alpha-ol-18(21)-olide (sylvestrosterol C), 2-methyl-6-methylene-n-decan-2-olyl- 3beta-D-glucopyranoside (malvanoyl glucoside), cholest-7-en-18(21)-olide-3alpha-olyl-3beta-D-glucopyranoside (sylvestrogenin A), cholest-9(11)-en-18(21)-olide-3alpha-olyl-3beta-D-glucopyranoside (sylvestrogenin B) and cholest-5-en-8(21)-olide-3alpha-olyl-3beta-D-glucopyranoside (sylvestrogenin C).The structures of all these phytoconstituents have been established on the basis of spectral data analysis and chemical reactions.

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

    PubMed Central

    Kitamura, Aya; Quinetti, Paes C.; Nakagami, Gojiro; Mugita, Yuko; Oe, Makoto; Noguchi, Hiroshi; Mori, Taketoshi; Sanada, Hiromi

    2016-01-01

    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. PMID:27404587

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

  16. The sesquiterpene lactone parthenolide induces selective apoptosis of B-chronic lymphocytic leukemia cells in vitro.

    PubMed

    Steele, A J; Jones, D T; Ganeshaguru, K; Duke, V M; Yogashangary, B C; North, J M; Lowdell, M W; Kottaridis, P D; Mehta, A B; Prentice, A G; Hoffbrand, A V; Wickremasinghe, R G

    2006-06-01

    We have studied the in vitro actions of the sesquiterpene lactone parthenolide (PTL) on cells isolated from patients with chronic lymphocytic leukemia (CLL). Dye reduction viability assays showed that the median LD(50) for PTL was 6.2 muM (n=78). Fifteen of these isolates were relatively resistant to the conventional agent chlorambucil but retained sensitivity to PTL. Brief exposures to PTL (1-3 h) were sufficient to induce caspase activation and commitment to cell death. Chronic lymphocytic leukemia cells were more sensitive towards PTL than were normal T lymphocytes or CD34(+) haematopoietic progenitor cells. The mechanism of cell killing was via PTL-induced generation of reactive oxygen species, resulting in turn in a proapoptotic Bax conformational change, release of mitochondrial cytochrome c and caspase activation. Parthenolide also decreased nuclear levels of the antiapoptotic transcription factor nuclear factor-kappa B and diminished phosphorylation of its negative regulator IkappaB. Killing of CLL cells by PTL was apparently independent of p53 induction. This is the first report showing the relative selectivity of PTL towards CLL cells. The data here warrant further investigation of this class of natural product as potential therapeutic agents for CLL.

  17. Bromoenol lactone enhances the permeabilization of rat submandibular acinar cells by P2X7 agonists

    PubMed Central

    Chaïb, N; Kabré, E; Alzola, E; Pochet, S; Dehaye, J P

    2000-01-01

    The permeabilizing effect of P2X7 agonists was tested in rat submandibular acinar cells using the uptake of ethidium bromide as an index. The uptake of ethidium bromide by acini incubated at 37°C in the presence of 1 mM ATP increased with time and reached after 5 min about 10% of maximal uptake measured in the presence of digitonin. The response to ATP was dose-dependent (half-maximal concentration around 40 μM) and it was decreased when the temperature was lowered to 25°C. Benzoyl-ATP reproduced the response to ATP (half-maximal concentration around 10 μM). UTP or 2-methylthioATP had no effect. The permeabilization in response to ATP was blocked by oxidized ATP and by magnesium and inhibited by Coomassie blue. ATP increased the activity of a calcium-insensitive phospholipase A2 (iPLA2). Bromoenol lactone (BEL) inhibited the iPLA2 stimulated by ATP but potentiated the uptake of ethidium bromide in response to the purinergic agonist. From these results it is concluded that the activation of P2X7 receptors permeabilizes rat submandibular acinar cells. The pore-forming activity of the receptor might be negatively regulated by the concomitant activation of the iPLA2 by the receptor. PMID:10683195

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

    PubMed

    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.

  19. Acyl-homoserine lactone-dependent eavesdropping promotes competition in a laboratory co-culture model

    PubMed Central

    Chandler, Josephine R; Heilmann, Silja; Mittler, John E; Greenberg, E Peter

    2012-01-01

    Many Proteobacteria use acyl-homoserine lactone (AHL)-mediated quorum sensing to activate the production of antibiotics at high cell density. Extracellular factors like antibiotics can be considered public goods shared by individuals within a group. Quorum-sensing control of antibiotic production may be important for protecting a niche or competing for limited resources in mixed bacterial communities. To begin to investigate the role of quorum sensing in interspecies competition, we developed a dual-species co-culture model using the soil saprophytes Burkholderia thailandensis (Bt) and Chromobacterium violaceum (Cv). These bacteria require quorum sensing to activate the production of antimicrobial factors that inhibit growth of the other species. We demonstrate that quorum-sensing-dependent antimicrobials can provide a competitive advantage to either Bt or Cv by inhibiting growth of the other species in co-culture. Although the quorum-sensing signals differ for each species, we show that the promiscuous signal receptor encoded by Cv can sense signals produced by Bt, and that this ability to eavesdrop on Bt can provide Cv an advantage in certain situations. We use an in silico approach to investigate the effect of eavesdropping in competition, and show conditions where early activation of antibiotic production resulting from eavesdropping can promote competitiveness. Our work supports the idea that quorum sensing is important for interspecies competition and that promiscuous signal receptors allow eavesdropping on competitors in mixed microbial habitats. PMID:22763647

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

    PubMed

    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.

  1. Sesquiterpene lactones from Lychnophora pohlii: neutrophil chemiluminescence inhibition and free radical scavenger activity.

    PubMed

    Kanashiro, Alexandre; Kabeya, Luciana M; Grael, Cristiane F F; Jordão, Christiane O; Azzolini, Ana Elisa C S; Lopes, João Luis C; Lucisano-Valim, Yara M

    2006-06-01

    Excessive production of reactive oxygen species (ROS) by polymorphonuclear leucocytes (PMNLs) is thought to contribute to the pathology of many inflammatory diseases. Sesquiterpene lactones (STLs) seem to be important contributors to the anti-inflammatory activity of many species of Lychnophora (Asteraceae), which have been widely used in Brazilian folk medicine because of this pharmacological property. In this study, the inhibitory effects of three STLs isolated from Lychnophora pohlii (lychnopholide, centratherin and goyazensolide) on rabbit PMNL oxidative burst were evaluated by the luminol-enhanced chemiluminescence (CL-lum) assay. All STLs tested showed concentration-dependent inhibitory activity on CL-lum but were not cytotoxic to PMNLs (evaluated by lactate dehydrogenase release) under the assessed conditions. Moreover, goyazensolide, the most active STL, had no free radical scavenger property, as assessed by 1,1-diphenyl-2picrylhydrazyl radical assay, and had no inhibitory effect on the luminol-horseradish peroxidase-hydrogen peroxide chemiluminescence. Taken together, the results of this investigation suggest that the concomitant presence of methacrylate ester and hydroxyl groups contributes to a high inhibitory effect on PMNL oxidative metabolism. This effect was not mediated by free radical scavenger or cytotoxic effects, but probably by inhibition of enzymes involved in the signal transduction pathways of the ROS generation process.

  2. A New Antimicrobial Prenylated Benzo-lactone from the Rhizome of Cissus cornifolia

    PubMed Central

    Musa, Aliyu M.; Tajuddeen, Nasir; Idris, Abdullahi Y.; Rafindadi, Abdurahman Y.; Abdullahi, Musa I.; Aliyu, Abubakar B.; Abdullahi, Mikhail S.; Ibrahim, Mohammed A.

    2015-01-01

    Background: Medicinal plants remain one of the largest reservoirs of new bioactive compounds. In this study, a new prenylated benzo-lactone (4, 6-dihydroxy-5-methoxy-3-(1, 2, 3, 4, 5-pentahydroxypentyl)-2-benzofuran-1(3H)-one) was isolated from the acetone extracts of the rhizome of Cissus cornifolia. The antimicrobial activity of the compound was evaluated against some microorganisms including Staphylococcus aureus, Salmonella typhi, and Candida albicans. Materials and Methods: The acetone extracts of the rhizome of C. cornifolia was separated and purified by various chromatographic techniques. The structure of the isolated compound was characterized by analysis of spectral data including one and two-dimensional nuclear magnetic resonance. Results: The isolated compound was characterized as (4, 6-dihydroxy-5-methoxy-3-(1, 2, 3, 4, 5-pentahydroxypentyl)-2-benzofuran-1(3H)-one), it showed activity against 6 out of 10 tested clinical isolates of some microorganisms including S. aureus, S. typhi, and C. albicans. The inhibition zones ranged between 17 mm and 25 mm. The inhibition zones observed compare favorably with the positive control used. Conclusion: The compound could serve as a lead for the development of more potent antimicrobial agent. To the best of our knowledge, this is the first report of the isolation and characterization as well as antimicrobial screening of the compound. PMID:26692751

  3. In vitro immunomodulatory properties of a sesquiterpene lactone-bearing fraction from Artemisia khorassanica.

    PubMed

    Zamanai Taghizadeh Rabe, Shahrzad; Iranshahi, Mehrdad; Rastin, Maryam; Tabasi, Nafise; Mahmoudi, Mahmoud

    2015-01-01

    Artemisia species are important medicinal plants throughout the world. The present in vitro study, using a sesquiterpene lactone-bearing fraction prepared from Artemisia khorassanica (SLAK), sought to investigate immunomodulatory/anti-inflammatory properties of this plant and elucidate potential underlying mechanisms for the actions. Effects of the SLAK on mitogen-induced murine splenocyte proliferation and interleukin (IL)-4 and interferon (IFN)-γ secretion were evaluated. To assess anti-inflammatory activities, levels of inducible of nitric oxide (NO) and prostaglandin E2 (PGE2), as well as expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in peritoneal macrophages was examined. The results showed that SLAK noticeably was capable of suppressing PHA/LPS-stimulated splenocyte proliferation and of up-regulating production of the T-helper (TH)-2 cell cytokine IL-4 while down-regulating formation of TH1 IFNγ. In addition, while SLAK caused negligible proliferation inhibition, peritoneal macrophages displayed considerable decrease in NO and PGE2 production along with iNOS and COX-2 expression. The current experiment shows Artemisia khorasanica - a traditionally used herb - may have immunomodulatory and anti-inflammatory effects. It is anticipated that the ingredients may be employed as therapeutic candidates in the regulation of some immune responses implicated in various conditions and ailments.

  4. The Sesquiterpene Lactone Dehydroleucodine Triggers Senescence and Apoptosis in Association with Accumulation of DNA Damage Markers

    PubMed Central

    Costantino, Valeria V.; Mansilla, Sabrina F.; Speroni, Juliana; Amaya, Celina; Cuello-Carrión, Darío; Ciocca, Daniel R.; Priestap, Horacio A.; Barbieri, Manuel A.; Gottifredi, Vanesa; Lopez, Luis A.

    2013-01-01

    Sesquiterpene lactones (SLs) are plant-derived compounds that display anti-cancer effects. Some SLs derivatives have a marked killing effect on cancer cells and have therefore reached clinical trials. Little is known regarding the mechanism of action of SLs. We studied the responses of human cancer cells exposed to various concentrations of dehydroleucodine (DhL), a SL of the guaianolide group isolated and purified from Artemisia douglasiana (Besser), a medicinal herb that is commonly used in Argentina. We demonstrate for the first time that treatment of cancer cells with DhL, promotes the accumulation of DNA damage markers such as phosphorylation of ATM and focal organization of γH2AX and 53BP1. This accumulation triggers cell senescence or apoptosis depending on the concentration of the DhL delivered to cells. Transient DhL treatment also induces marked accumulation of senescent cells. Our findings help elucidate the mechanism whereby DhL triggers cell cycle arrest and cell death and provide a basis for further exploration of the effects of DhL in in vivo cancer treatment models. PMID:23341930

  5. Roasted coffees high in lipophilic antioxidants and chlorogenic acid lactones are more neuroprotective than green coffees.

    PubMed

    Chu, Yi-Fang; Brown, Peter H; Lyle, Barbara J; Chen, Yumin; Black, Richard M; Williams, Claire E; Lin, Yi-Ching; Hsu, Chih-Wei; Cheng, Irene H

    2009-10-28

    Oxidative stress is involved in many neurodegenerative processes leading to age-related cognitive decline. Coffee, a widely consumed beverage, is rich in many bioactive components, including polyphenols with antioxidant potential. In this study, regular and decaffeinated samples of both roasted and green coffee all showed high hydrophilic antioxidant activity in vitro, whereas lipophilic antioxidant activities were on average 30-fold higher in roasted than in green coffee samples. In primary neuronal cell culture, pretreatment with green and roasted coffees (regular and decaffeinated) protected against subsequent H(2)O(2)-induced oxidative stress and improved neuronal cell survival (green coffees increased neuron survival by 78%, compared to 203% by roasted coffees). All coffee extracts inhibited ERK1/2 activation, indicating a potential attenuating effect in stress-induced neuronal cell death. Interestingly, only roasted coffee extracts inhibited JNK activation, evidencing a distinctive neuroprotective benefit. Analysis of coffee phenolic compounds revealed that roasted coffees contained high levels of chlorogenic acid lactones (CGLs); a significant correlation between CGLs and neuroprotective efficacy was observed (R(2) = 0.98). In conclusion, this study showed that roasted coffees are high in lipophilic antioxidants and CGLs, can protect neuronal cells against oxidative stress, and may do so by modulation of the ERK1/2 and JNK signaling pathways.

  6. Synthesis of a novel ether-bridged GM3-lactone analogue as a target for an antibody-based cancer therapy.

    PubMed

    Tietze, L F; Keim, H; Janssen, C O; Tappertzhofen, C; Olschimke, J

    2000-08-04

    We describe herein the synthesis of a new analogue of the GM3-lactone containing a cyclic ether moiety. The ether moiety was chosen as a replacement for the regular lactone group since it shows high resemblance with the lactone and is completely stable under biological conditions. The cyclic ether moiety was formed by reduction of the corresponding lactone to give the lactol followed by formation of the S,O-hemiacetal and hydrogenation. In addition, we have prepared haptens with a hexanoic acid moiety, which can be used for the preparation of poly- and monoclonal antibodies after binding to BSA or KLH. This is the first example of an analogue of the GM3-lactone which is stable under hydrolytic conditions in vitro and probably also in vivo. Reaction of lactone 18 with a Red/Al derivative led to the lactol 19 which was transformed into the S,O-hemiacetal 20 using 2,2'-bis(pyridinium) disulfide in quantitative yield. Hydrogenation with Raney Nickel gave 21 from which after removal of the protecting group at C-1a the trichloroacetimidate 25 was prepared. Reaction with azidosphingosine to give 26 followed by reduction of the azido group with NHEt3+[(PhS)3Sn], acylation with stearic acid using EDC and removal of the protecting groups led to the desired ether analogue of GM3 lactone 4. In addition the trichloroacetimidate 25 was glycosidated with 6-hydroxyhexanoic acid methyl ester, which was deprotected to give 29. The compound will be used for the preparation of poly- and monoclonal antibodies after coupling with BSA and KLH.

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

    PubMed

    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.

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

    PubMed

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

    2017-03-10

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

  9. Estimation of Costunolide and Dehydrocostus Lactone in Saussurea lappa and its Polyherbal Formulations followed by their Stability Studies Using HPLC-DAD

    PubMed Central

    Rao Vadaparthi, P.R.; Kumar, K.; Sarma, Vanka Uma Maheswara; Hussain, Qazi Altaf; Babu, K. Suresh

    2015-01-01

    Background: Saussurea lappa is one of the popular Ayurvedic herb; costunolide and dehydrocostus lactones are well-known sesquiterpene lactones contained in many plants used as popular herbs, such as S. lappa, and have been considered as potential candidates for the treatment of various types of tumor. Objective: The present study was used for the quantification of costunolide and dehydrocostus lactone in S. lappa and its polyherbal formulations, stability studies of markers and characterization of their degradants. Materials and Methods: HPLC analysis was performed on Waters NOVAPAK HR C18 column (300 mm × 3.9 mm i.d., 6 μm) using isocratic elution with acetonitrile and water (60:40% v/v). Results: The calibration curves of both analytes showed good linearity within the established range 5-100 μg/ml. The limits of detection (LOD) and quantification (LOQ) were 1.5 and 4.6 μg/ml for costunolide and 1.3 and 4.0 μg/ml for dehydrocostus lactone, respectively. Good results were achieved with respect to repeatability (%RSD < 2.0) and recovery (99.3-101.8%). Conclusion: The method was found to be precise, accurate, specific, and was successfully used for analyzing costunolide and dehydrocostus lactone in S. lappa and its polyherbal formulations. The developed method was found to be suitable for stability studies of markers and characterization of their degradation products. PMID:25709231

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

    PubMed

    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.

  11. Macrocyclic lactones in the treatment and control of parasitism in small companion animals.

    PubMed

    Nolan, Thomas J; Lok, James B

    2012-05-01

    Macrocyclic lactones (MLs) have many anti-parasitic applications in small companion animal medicine. They were first developed as chemoprophylactics against heartworm (Dirofilaria immitis) infection to be applied monthly for retroactive killing of third- and fourth-stage larvae. ML-containing products formulated for oral (ivermectin, milbemycin oxime), topical (selamectin, moxidectin) or injectable sustained release (moxidectin, ivermectin) are approved for heartworm prevention in dogs or cats. Clearance of microfilariae and gradual or "soft" killing of adult heartworms constitute increasingly prevalent extra-label uses of MLs against D. immitis. Some commercial ML formulations contain sufficient levels of active ingredient (milbemycin oxime, selamectin, moxidectin) to support additional label claims against gastrointestinal nematode parasites such as hookworms (Ancylostoma spp.) and ascarid round worms (Toxocara spp. and Toxascaris leonina). Beyond these approved applications, safe, extra-label uses of MLs against nematodes parasitizing the urinary tract, such as Capillaria spp., and parasites of the tissues, such as Dipetalonema reconditum, Dirofilaria repens, Thelazia spp. and Spirocerca lupi, in dogs and cats as well as exotic pets have been reported. MLs as a group have intrinsic insecticidal and acaricidal activity, and topical or otic formulations of certain compounds (selamectin, moxidectin, milbemycin oxime or ivermectin) are approved for treatment and control of fleas, certain ixodid ticks, sarcoptiform and demodectic mange mites and psoroptiform ear mites. Extra-label applications of MLs against ectoparasites include notoedric mange mites, dermanyssids such as Ornythonussus bacoti, numerous species of fur mite (e.g. Cheyletiella spp. and Lynxacarus) and trombiculids ("chiggers") in cats, dogs and nontraditional or exotic pets.

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

    PubMed

    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.

  13. The Nonartemisinin Sesquiterpene Lactones Parthenin and Parthenolide Block Plasmodium falciparum Sexual Stage Transmission

    PubMed Central

    Balaich, Jared N.; Mathias, Derrick K.; Torto, Baldwyn; Jackson, Bryan T.; Tao, Dingyin; Ebrahimi, Babak; Tarimo, Brian B.; Cheseto, Xavier; Foster, Woodbridge A.

    2016-01-01

    Parthenin and parthenolide are natural products that are closely related in structure to artemisinin, which is also a sesquiterpene lactone (SQL) and one of the most important antimalarial drugs available. Parthenin, like artemisinin, has an effect on Plasmodium blood stage development. We extended the evaluation of parthenin as a potential therapeutic for the transmissible stages of Plasmodium falciparum as it transitions between human and mosquito, with the aim of gaining potential mechanistic insight into the inhibitory activity of this compound. We posited that if parthenin targets different biological pathways in the parasite, this in turn could pave the way for the development of druggable compounds that could prevent the spread of artemisinin-resistant parasites. We examined parthenin's effect on male gamete activation and the ookinete-to-oocyst transition in the mosquito as well as on stage V gametocytes that are present in peripheral blood. Parthenin arrested parasite development for each of the stages tested. The broad inhibitory properties of parthenin on the evaluated parasite stages may suggest different mechanisms of action between parthenin and artemisinin. Parthenin's cytotoxicity notwithstanding, its demonstrated activity in this study suggests that structurally related SQLs with a better safety profile deserve further exploration. We used our battery of assays to test parthenolide, which has a more compelling safety profile. Parthenolide demonstrated activity nearly identical to that of parthenin against P. falciparum, highlighting its potential as a possible transmission-blocking drug scaffold. We discuss the context of the evidence with respect to the next steps toward expanding the current antimalarial arsenal. PMID:26787692

  14. The Nonartemisinin Sesquiterpene Lactones Parthenin and Parthenolide Block Plasmodium falciparum Sexual Stage Transmission.

    PubMed

    Balaich, Jared N; Mathias, Derrick K; Torto, Baldwyn; Jackson, Bryan T; Tao, Dingyin; Ebrahimi, Babak; Tarimo, Brian B; Cheseto, Xavier; Foster, Woodbridge A; Dinglasan, Rhoel R

    2016-04-01

    Parthenin and parthenolide are natural products that are closely related in structure to artemisinin, which is also a sesquiterpene lactone (SQL) and one of the most important antimalarial drugs available. Parthenin, like artemisinin, has an effect onPlasmodiumblood stage development. We extended the evaluation of parthenin as a potential therapeutic for the transmissible stages ofPlasmodium falciparumas it transitions between human and mosquito, with the aim of gaining potential mechanistic insight into the inhibitory activity of this compound. We posited that if parthenin targets different biological pathways in the parasite, this in turn could pave the way for the development of druggable compounds that could prevent the spread of artemisinin-resistant parasites. We examined parthenin's effect on male gamete activation and the ookinete-to-oocyst transition in the mosquito as well as on stage V gametocytes that are present in peripheral blood. Parthenin arrested parasite development for each of the stages tested. The broad inhibitory properties of parthenin on the evaluated parasite stages may suggest different mechanisms of action between parthenin and artemisinin. Parthenin's cytotoxicity notwithstanding, its demonstrated activity in this study suggests that structurally related SQLs with a better safety profile deserve further exploration. We used our battery of assays to test parthenolide, which has a more compelling safety profile. Parthenolide demonstrated activity nearly identical to that of parthenin againstP. falciparum, highlighting its potential as a possible transmission-blocking drug scaffold. We discuss the context of the evidence with respect to the next steps toward expanding the current antimalarial arsenal.

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

    PubMed Central

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

    2014-01-01

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

  16. Acyl homoserine lactone-based quorum sensing stimulates biofilm formation by Salmonella Enteritidis in anaerobic conditions.

    PubMed

    Almeida, Felipe Alves de; Pimentel-Filho, Natan de Jesus; Pinto, Uelinton Manoel; Mantovani, Hilário Cuquetto; Oliveira, Leandro Licursi de; Vanetti, Maria Cristina Dantas

    2017-04-01

    Quorum sensing regulates a variety of phenotypes in bacteria including the production of virulence factors. Salmonella spp. have quorum sensing systems mediated by three autoinducers (AI-1, AI-2, and AI-3). The AI-1-mediated system is incomplete in that the bacterium relies on the synthesis of signaling molecules by other microorganisms. This study aimed to evaluate the influence of the AI-1 N-dodecanoyl-DL-homoserine lactone (C12-HSL) on the growth, motility, adhesion, and biofilm formation of Salmonella enterica serovar Enteritidis PT4 578 on a polystyrene surface. Experiments were conducted at 37 °C in anaerobic tryptone soy broth supplemented with C12-HSL and/or a mixture of four synthetic furanones, at the concentration of 50 nM each. The planktonic growth, adhesion, swarming, and twitching motility were not altered in the presence of C12-HSL and/or furanones under anaerobic conditions. However, C12-HSL induced biofilm formation after 36 h of cultivation as determined by quantification of biofilm formation, by enumeration of adhered cells to polystyrene coupons, and finally by imaging the presence of multilayered cells on an epifluorescence microscope. When furanones were present in the medium, an antagonistic effect against C12-HSL on the biofilm development was observed. The results demonstrate an induction of biofilm formation in Salmonella Enteritidis by AI-1 under anaerobic conditions. Considering that Salmonella does not produce AI-1 but respond to it, C12-HSL synthesized by other bacterial species could trigger biofilm formation by this pathogen in conditions that are relevant for its pathogenesis.

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

    PubMed Central

    Frank, F. M.; Ulloa, J.; Cazorla, S. I.; Maravilla, G.; Malchiodi, E. L.; Grau, A.; Martino, V.; Catalán, C.; Muschietti, L. V.

    2013-01-01

    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. PMID:23840260

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

    PubMed Central

    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

  19. Molecular identification of tuliposide B-converting enzyme: a lactone-forming carboxylesterase from the pollen of tulip.

    PubMed

    Nomura, Taiji; Murase, Tatsunori; Ogita, Shinjiro; Kato, Yasuo

    2015-07-01

    6-Tuliposides A (PosA) and B (PosB), which are the major secondary metabolites in tulip (Tulipa gesneriana), are enzymatically converted to the antimicrobial lactonized aglycons, tulipalins A (PaA) and B (PaB), respectively. We recently identified a PosA-converting enzyme (TCEA) as the first reported member of the lactone-forming carboxylesterases. Herein, we describe the identification of another lactone-forming carboxylesterase, PosB-converting enzyme (TCEB), which preferentially reacts with PosB to give PaB. This enzyme was isolated from tulip pollen, which showed high PosB-converting activity. Purified TCEB exhibited greater activity towards PosB than PosA, which was contrary to that of the TCEA. Novel cDNA (TgTCEB1) encoding the TCEB was isolated from tulip pollen. TgTCEB1 belonged to the carboxylesterase family and was approximately 50% identical to the TgTCEA polypeptides. Functional characterization of the recombinant enzyme verified that TgTCEB1 catalyzed the conversion of PosB to PaB with an activity comparable with the native TCEB. RT-qPCR analysis of each part of plant revealed that TgTCEB1 transcripts were limited almost exclusively to the pollen. Furthermore, the immunostaining of the anther cross-section using anti-TgTCEB1 polyclonal antibody verified that TgTCEB1 was specifically expressed in the pollen grains, but not in the anther cells. N-terminal transit peptide of TgTCEB1 was shown to function as plastid-targeted signal. Taken together, these results indicate that mature TgTCEB1 is specifically localized in plastids of pollen grains. Interestingly, PosB, the substrate of TgTCEB1, accumulated on the pollen surface, but not in the intracellular spaces of pollen grains.

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

    PubMed

    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.

  1. Evidence for the possible existence of a remnant L-gulono-gamma-lactone oxidase (GULO) gene in a teleost genome.

    PubMed

    Ocalewicz, Konrad; Dabrowski, Konrad; Mambrini, Muriel

    2010-01-01

    DNA fragments related to the cloudy catshark Scyliorhinus torazame L-gulono-gamma-lactone oxidase (GULO) cDNA were detected in a distant fish species. Although the Southern hybridization pattern was more distinct in species with active GULO, DNA fragments related to the GULO gene were also discovered in the common carp Cyprinus carpio. Additionally, in the common carp, inter-individual variation of the hybridization pattern was observed. Regular screening of available teleost fish gene libraries did not reveal GULO related DNA sequences.

  2. Crystal Violet Lactone Salicylaldehyde Hydrazone Zn(II) Complex: a Reversible Photochromic Material both in Solution and in Solid Matrix

    NASA Astrophysics Data System (ADS)

    Li, Kai; Li, Yuanyuan; Tao, Jing; Liu, Lu; Wang, Lili; Hou, Hongwei; Tong, Aijun

    2015-09-01

    Crystal violet lactone (CVL) is a classic halochromic dye which has been widely used as chromogenic reagent in thermochromic and piezochromic systems. In this work, a very first example of CVL-based reversible photochromic compound was developed, which showed distinct color change upon UV-visible light irradiation both in solution and in solid matrix. Moreover, metal complex of CVL salicylaldehyde hydrozone was facilely synthesized, exhibiting reversible photochromic properties with good fatigue resistance. It was served as promising solid material for photo-patterning.

  3. Crystal Violet Lactone Salicylaldehyde Hydrazone Zn(II) Complex: a Reversible Photochromic Material both in Solution and in Solid Matrix.

    PubMed

    Li, Kai; Li, Yuanyuan; Tao, Jing; Liu, Lu; Wang, Lili; Hou, Hongwei; Tong, Aijun

    2015-09-28

    Crystal violet lactone (CVL) is a classic halochromic dye which has been widely used as chromogenic reagent in thermochromic and piezochromic systems. In this work, a very first example of CVL-based reversible photochromic compound was developed, which showed distinct color change upon UV-visible light irradiation both in solution and in solid matrix. Moreover, metal complex of CVL salicylaldehyde hydrozone was facilely synthesized, exhibiting reversible photochromic properties with good fatigue resistance. It was served as promising solid material for photo-patterning.

  4. Crystal Violet Lactone Salicylaldehyde Hydrazone Zn(II) Complex: a Reversible Photochromic Material both in Solution and in Solid Matrix

    PubMed Central

    Li, Kai; Li, Yuanyuan; Tao, Jing; Liu, Lu; Wang, Lili; Hou, Hongwei; Tong, Aijun

    2015-01-01

    Crystal violet lactone (CVL) is a classic halochromic dye which has been widely used as chromogenic reagent in thermochromic and piezochromic systems. In this work, a very first example of CVL-based reversible photochromic compound was developed, which showed distinct color change upon UV-visible light irradiation both in solution and in solid matrix. Moreover, metal complex of CVL salicylaldehyde hydrozone was facilely synthesized, exhibiting reversible photochromic properties with good fatigue resistance. It was served as promising solid material for photo-patterning. PMID:26412101

  5. Characteristics of N-Acylhomoserine Lactones Produced by Hafnia alvei H4 Isolated from Spoiled Instant Sea Cucumber.

    PubMed

    Hou, Hong-Man; Zhu, Yao-Lei; Wang, Jia-Ying; Jiang, Feng; Qu, Wen-Yan; Zhang, Gong-Liang; Hao, Hong-Shun

    2017-04-05

    This study aimed to identify N-acylhomoserine lactone (AHL) produced by Hafnia alvei H4, which was isolated from spoiled instant sea cucumber, and to investigate the effect of AHLs on biofilm formation. Two biosensor strains, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens KYC55, were used to detect the quorum sensing (QS) activity of H. alvei H4 and to confirm the existence of AHL-mediated QS system. Thin layer chromatography (TLC) and high resolution triple quadrupole liquid chromatography/mass spectrometry (LC/MS) analysis of the AHLs extracted from the culture supernatant of H. alvei H4 revealed the existence of at least three AHLs: N-hexanoyl-l-homoserine lactone (C6-HSL), N-(3-oxo-octanoyl)-l-homoserine lactone (3-oxo-C8-HSL), and N-butyryl-l-homoserine lactone (C4-HSL). This is the first report of the production of C4-HSL by H. alvei. In order to determine the relationship between the production of AHL by H. alvei H4 and bacterial growth, the β-galactosidase assay was employed to monitor AHL activity during a 48-h growth phase. AHLs production reached a maximum level of 134.6 Miller unites at late log phase (after 18 h) and then decreased to a stable level of about 100 Miller unites. AHL production and bacterial growth displayed a similar trend, suggesting that growth of H. alvei H4 might be regulated by QS. The effect of AHLs on biofilm formation of H. alvei H4 was investigated by adding exogenous AHLs (C4-HSL, C6-HSL and 3-oxo-C8-HSL) to H. alvei H4 culture. Biofilm formation was significantly promoted (p < 0.05) by 5 and 10 µM C6-HSL, inhibited (p < 0.05) by C4-HSL (5 and 10 µM) and 5 µM 3-oxo-C8-HSL, suggesting that QS may have a regulatory role in the biofilm formation of H. alvei H4.

  6. Terpenylic and Related Lactone-Containing Acids: Novel Monoterpene Secondary Organic Aerosol Tracers with Dimer-Forming Properties

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Iinuma, Y.; Szmigielski, R.; Farhat, Y.; Surratt, J. D.; Blockhuys, F.; van Alsenoy, C.; Böge, O.; Sierau, B.; Gómez-González, Y.; Vermeylen, R.; van der Veken, P.; Shahgholi, M.; Chan, A. W.; Herrmann, H.; Seinfeld, J.; Maenhaut, W.

    2009-12-01

    Blue haze is a natural phenomenon that is observed in forested regions worldwide and is due to the formation of secondary organic aerosol (SOA) particles. While evidence exists for organic molecular clusters in the size range of < 2 nm, the chemical structures of the nucleating particles have remained unresolved. In the present study, novel SOA products from the monoterpene α-pinene with unique dimer-forming properties have been identified as lactone-containing terpenoic acids, i.e., terpenylic (molecular weight (MW) 172), terebic (MW 158) and 2-hydroxyterpenylic acid (MW 188), and diaterpenylic acid acetate (MW 232). The structural characterizations were based on synthesis of reference compounds and detailed interpretation of negative ion electrospray ionization mass spectral [(-)ESI-MS] data, including accurate mass and MSn ion trap measurements. Terpenylic acid and diaterpenylic acid acetate are early oxidation products formed upon both photooxidation and ozonolysis, and are abundant SOA tracers in ambient fine aerosol from coniferous forest sites (e.g., K-puszta, Hungary). Terebic and 2-hydroxyterpenylic acid can be explained by further oxidation of terpenylic acid, and are also prominent tracers in ambient fine aerosol. Quantum chemical calculations support that non-covalent dimer formation involving double hydrogen bonding interactions between carboxyl groups of the monomers is energetically favorable. Lactone-containing terpenoic acids also form through photooxidation from monoterpenes other than α-pinene, i.e., terebic acid from Δ3-carene, and terpenylic, homoterpenylic (MW 186), and terebic acid from β-pinene. A distinct feature of terpenylic acid and related lactone-containing acids is that they can be selectively detected in positive ion (+)ESI-MS, unlike isobaric dicarboxylic terpenoic acids such as norpinic (MW 172) and pinic acid (MW 186). Interestingly, terpenylic, terebic and homoterpenylic acid were already reported in the early German

  7. (1)H, (13)C NMR and X-ray crystallographic studies of highly polyhalogenated derivatives of costunolide lactone.

    PubMed

    Corona, D; Díaz, E; Nava, J L; Guzmán, A; Barrios, H; Fuentes, A; Hernandez-Plata, S A; Allard, J; Jankowski, C K

    2005-11-01

    The costunolide lactone, a sesquiterpene compound isolated from Zaluzania triiloba species, reacted with several dihalocarbene sources produced by trihaloform-NaOH under successive phase transfer reactions yielding mono-, bis- and tris-dihalocyclopropane adducts. The structures, as well as the configurational assignments of the different derivatives, were established by (1)H and (13)C NMR spectroscopy and assisted by X-ray crystallographic and molecular modelling studies. The specific shielding of protons in the neighbourhood of different halogens on the cyclopropane moieties was correlated to the pseudocontact interactions.

  8. Design, synthesis and biological evaluation of N-sulfonyl homoserine lactone derivatives as inhibitors of quorum sensing in Chromobacterium violaceum.

    PubMed

    Zhao, Mingming; Yu, Yingying; Hua, Yuhui; Feng, Fan; Tong, Yigang; Yang, Xiaohong; Xiao, Junhai; Song, Hongrui

    2013-03-13

    A novel series of N-sulfonyl homoserine lactone derivatives 5a-l has been designed, synthesized and evaluated for quorum sensing inhibitory activities towards violacein production. Of the compounds synthesized, compound 5h was found to possess an excellent level of enantiopurity (99.2% e.e.). The results indicated that compounds bearing an ortho substituent on their phenyl ring exhibited excellent levels of inhibitory activity against violacein production. Compounds 5h and 5k in particular, with IC₅₀ values of 1.64 and 1.66 µM, respectively, were identified as promising lead compounds for further structural modification.

  9. Vlasouliolides A-D, four rare C17/C15 sesquiterpene lactone dimers with potential anti-inflammatory activity from Vladimiria souliei

    NASA Astrophysics Data System (ADS)

    Chen, Li-Ping; Wu, Guo-Zhen; Zhang, Jian-Ping; Ye, Ji; Liu, Qing-Xin; Shen, Yun-Heng; Li, Hui-Liang; Zhang, Wei-Dong

    2017-03-01

    Vlasouliolides A-D (1–4), four rare sesquiterpene lactone dimers, were isolated from Vladimiria souliei. The common structural characteristic of 1–4 is the C32 skeleton comprising two sesquiterpene lactone units linked by a C11-C13‧ single bond with one acetyl connected to the C-13 position of one of the two sesquiterpene lactone units. The stereochemistries of 1–4 were assigned by a combination of NOESY correlations and Cu-Κα X-ray crystallographic analyses. Compounds 1–4 strongly inhibited the production of NO in LPS-stimulated RAW 264.7 cells. Furthermore, 1 and 2 inhibited the activation of NF-κB in LPS-induced 293T cells.

  10. Vlasouliolides A-D, four rare C17/C15 sesquiterpene lactone dimers with potential anti-inflammatory activity from Vladimiria souliei

    PubMed Central

    Chen, Li-Ping; Wu, Guo-Zhen; Zhang, Jian-Ping; Ye, Ji; Liu, Qing-Xin; Shen, Yun-Heng; Li, Hui-Liang; Zhang, Wei-Dong

    2017-01-01

    Vlasouliolides A-D (1–4), four rare sesquiterpene lactone dimers, were isolated from Vladimiria souliei. The common structural characteristic of 1–4 is the C32 skeleton comprising two sesquiterpene lactone units linked by a C11-C13′ single bond with one acetyl connected to the C-13 position of one of the two sesquiterpene lactone units. The stereochemistries of 1–4 were assigned by a combination of NOESY correlations and Cu-Κα X-ray crystallographic analyses. Compounds 1–4 strongly inhibited the production of NO in LPS-stimulated RAW 264.7 cells. Furthermore, 1 and 2 inhibited the activation of NF-κB in LPS-induced 293T cells. PMID:28256560

  11. Crystal structure of 5-O-benzoyl-2,3-O-iso­propyl­idene-d-ribono-1,4-lactone

    PubMed Central

    Bortoluzzi, Adailton J.; Silveira, Gustavo P.; Sá, Marcus M.

    2017-01-01

    In the title compound, C15H16O6, obtained from the acyl­ation reaction between 2,3-O-iso­propyl­idene-d-ribono-1,4-lactone and benzoyl chloride, the known absolute configuration for the lactone moiety of the ester substituent has been confirmed. The five-membered rings of the bicyclic lactone–dioxolane moiety both show envelope conformations and form a dihedral angle of 19.82 (7)° between the lactone ring and the benzene ring. In the crystal, mol­ecules of the acyl­ated sugar are linked by very weak inter­molecular C—H⋯O inter­actions, forming a three-dimensional network. PMID:28316820

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

    PubMed

    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.

  13. Construction of Fused Pyrrolidines and β-Lactones by Carbene-Catalyzed C-N, C-C, and C-O Bond Formations.

    PubMed

    Wu, Xingxing; Hao, Lin; Zhang, Yuexia; Rakesh, Maiti; Reddi, Rambabu N; Yang, Song; Song, Bao-An; Chi, Yonggui Robin

    2017-03-15

    A carbene-catalyzed intermolecular C-N bond formation, which initiates a highly selective cascade reaction for the synthesis of pyrrolidine fused β-lactones, is disclosed. The nitrogen-containing bicyclic β-lactone products are obtained with good yields and excellent stereoselectivities. Synthetic transformations of the reaction products into useful functional molecules, such as amino catalysts, can be efficiently realized under mild reaction conditions. Mechanistically, this study provides insights into modulating the reactivities of heteroatoms, such as nitrogen atoms, in challenging carbene-catalyzed asymmetric carbon-heteroatom bond-forming reactions.

  14. Sensitive Whole-Cell Biosensor Suitable for Detecting a Variety of N-Acyl Homoserine Lactones in Intact Rhizosphere Microbial Communities▿

    PubMed Central

    DeAngelis, Kristen M.; Firestone, Mary K.; Lindow, Steven E.

    2007-01-01

    To investigate quorum sensing in rhizosphere soil, a whole-cell biosensor, Agrobacterium tumefaciens(pAHL-Ice), was constructed. The biosensor responded to all N-acyl homoserine lactones (AHLs) tested, except C4 homoserine lactone, with a minimum detection limit of 10−12 M, as well as to both exogenously added AHLs and AHL-producing bacterial strains in soil. This highly sensitive biosensor reveals for the first time the increased AHL availability in intact rhizosphere microbial communities compared to that in bulk soil. PMID:17400771

  15. New steroidal lactones as 5α-reductase inhibitors and antagonists for the androgen receptor.

    PubMed

    Garrido, Mariana; Bratoeff, Eugene; Bonilla, Dulce; Soriano, Juan; Heuze, Yvonne; Cabeza, Marisa

    2011-11-01

    This study reports the synthesis of several new steroidal lactones: 5α,6β-dibromo-17a-oxa-D-homoandrostane-3β-yl-3'-oxapentanoate (11), 5α,6β-dibromo-17a-oxa-D-homoandrostane-3β-yl-propanoate (12), 5α,6β-dibromo-17a-oxa-D-homoandrostane-3β-yl-butanoate (13), 5α,6β-dibromo-17a-oxa-D-homoandrostane-3β-yl-pentanoate (14), 5α,6β-dibromo-17a-oxa-D-homoandrostane-3β-yl-hexanoate (15), 17a-oxa-D-homoandrost-5-en-17-one-3β-yl-3'-oxapentanoate (16), 17a-oxa-D-homoandrost-5-en-17-one-3β-yl-propanoate (17), 17a-oxa-D-homoandrost-5-en-17-one-3β-yl-butanoate (18), 17a-oxa-D-homoandrost-5-en-17-one-3β-yl-pentanoate (19) and 17a-oxa-D-homoandrost-5-en-17-one-3β-yl-hexanoate (20) with a therapeutic potential as antiandrogens. The biological effect of these steroids was demonstrated in in vivo as well as in vitro experiments. In the in vivo experiments, we measured the activity of ten new steroidal derivatives on the weight of the prostate and seminal vesicle glands of gonadectomized hamsters treated with testosterone. For the in vitro studies, we determined the IC(50) values by measuring the concentration of the steroidal derivatives that inhibits 50% of the activity of the 5α-reductase enzyme present in human prostate and also its binding capacity to the androgen receptors (AR) obtained from rat's prostate cytosol. The results from these experiments indicated that compounds 11-20, significantly decreased the weight of the prostate and seminal vesicles as compared to testosterone treated animals; this reduction of the weight of these glands was comparable to that produced by Finasteride. On the other hand, compounds 11-20 inhibited the enzyme 5α-reductase, with compounds 14-19 (IC(50) values of 4.2 ± 0.95, 0.025 ± 0.003, 1.2 ± 0.45, 1.2 ± 0.1, 0.028 ± 0.003, and 0.069 ± 0.005 nM, respectively) showing the highest inhibitory activity. The results from the in vitro experiments indicated that only 15-17 bind to the AR.

  16. Bromoenol Lactone Inhibits Voltage-Gated Ca2+ and Transient Receptor Potential Canonical ChannelsS⃞

    PubMed Central

    Chakraborty, Saikat; Berwick, Zachary C.; Bartlett, Paula J.; Kumar, Sanjay; Thomas, Andrew P.; Sturek, Michael; Tune, Johnathan D.

    2011-01-01

    Circulating hormones stimulate the phospholipase Cβ (PLC)/Ca2+ influx pathway to regulate numerous cell functions, including vascular tone. It was proposed previously that Ca2+-independent phospholipase A2 (iPLA2)-dependent store-operated Ca2+ influx channels mediate hormone-induced contractions in isolated arteries, because bromoenol lactone (BEL), a potent irreversible inhibitor of iPLA2, inhibited such contractions. However, the effects of BEL on other channels implicated in mediating hormone-induced vessel contractions, specifically voltage-gated Ca2+ (CaV1.2) and transient receptor potential canonical (TRPC) channels, have not been defined clearly. Using isometric tension measurements, we found that thapsigargin-induced contractions were ∼34% of those evoked by phenylephrine or KCl. BEL completely inhibited not only thapsigargin- but also phenylephrine- and KCl-induced ring contractions, suggesting that CaV1.2 and receptor-operated TRPC channels also may be sensitive to BEL. Therefore, we investigated the effects of BEL on heterologously expressed CaV1.2 and TRPC channels in human embryonic kidney cells, a model system that allows probing of individual protein function without interference from other signaling elements of native cells. We found that low micromolar concentrations of BEL inhibited CaV1.2, TRPC5, TRPC6, and heteromeric TRPC1–TRPC5 channels in an iPLA2-independent manner. BEL also attenuated PLC activity, suggesting that the compound may inhibit TRPC channel activity in part by interfering with an initial PLC-dependent step required for TRPC channel activation. Conversely, BEL did not affect endogenous voltage-gated K+ channels in human embryonic kidney cells. Our findings support the hypothesis that iPLA2-dependent store-operated Ca2+ influx channels and iPLA2-independent hormone-operated TRPC channels can serve as smooth muscle depolarization triggers to activate CaV1.2 channels and to regulate vascular tone. PMID:21795434

  17. Isothiourea-Mediated Organocatalytic Michael Addition-Lactonization on a Surface: Modification of SAMs on Silicon Oxide Substrates.

    PubMed

    Chisholm, Ross; Parkin, John D; Smith, Andrew D; Hähner, Georg

    2016-04-05

    Tailoring the functionality of self-assembled monolayers (SAMs) can be achieved either by depositing prefunctionalized molecules with the appropriate terminal groups or by chemical modification of an existing SAM in situ. The latter approach is particularly advantageous to allow for diversity of surface functionalization from a single SAM and if the incorporation of bulky groups is desired. In the present study an organocatalytic isothiourea-mediated Michael addition-lactonization process analogous to a previously reported study in solution is presented. An achiral isothiourea, 3,4-dihydro-2H-pyrimido[2,1-b]benzothiazole (DHPB), promotes the intermolecular Michael addition-lactonization of a trifluoromethylenone terminated SAM and a variety of arylacetic acids affording C(6)-trifluoromethyldihydropyranones tethered to the surface. X-ray photoelectron spectroscopy, atomic force microscopy, contact angle, and ellipsometry analysis were conducted to confirm the presence of the substituted dihydropyranone. A model study of this approach was also performed in solution to probe the reaction diastereoselectivity as it cannot be measured directly on the surface.

  18. Induction of human leukemia cell differentiation via PKC/MAPK pathways by arsantin, a sesquiterpene lactone from Artemisia santolina.

    PubMed

    Kweon, Sin Ho; Song, Ju Han; Kim, Hee Jin; Kim, Tae Sung; Choi, Bo Gil

    2015-11-01

    Sesquiterpene lactone compounds have received considerable attention in pharmacological research due to their therapeutic effects including anti-cancer and anti-inflammatory activities. In this report, we investigated the effect of arsantin, a sesquiterpene lactone compound present in Artemisia santolina, on cellular differentiation in the human promyelocytic leukemia HL-60 cell culture system. Arsantin significantly induced HL-60 cell differentiation in a concentration-dependent manner. Cytofluorometric analysis indicated that arsantin induced HL-60 cell differentiation predominantly into granulocytes. Both PKC and MAPK inhibitors suppressed the HL-60 cell differentiation induced by arsantin. Moreover, treatment with arsantin increased protein levels of PKCα and PKCβII isoforms, and also induced increased protein levels and phosphorylation form of MAPKs in HL-60 cells. Importantly, arsantin synergistically enhanced differentiation of HL-60 cells in a dose-dependent manner when combined with either low doses of 1,25-(OH)2D3 or ATRA. The ability to enhance the differentiation potential of 1,25-(OH)2D3 or ATRA by arsantin may improve outcomes in the therapy of acute promyelocytic leukemia.

  19. Cyclic AMP and acyl homoserine lactones increase the cultivation efficiency of heterotrophic bacteria from the central Baltic Sea.

    PubMed

    Bruns, Alke; Cypionka, Heribert; Overmann, Jörg

    2002-08-01

    The effect of signal molecules on the cultivation efficiency of bacteria from the Gotland Deep in the central Baltic Sea was investigated. Numbers of cultivated cells were determined by the most-probable-number (MPN) technique. Artificial brackish water supplemented with different carbon substrates at low concentrations (200 microM each) was employed as the growth medium. Compared to the results of previous studies, this approach yielded significantly higher cultivation efficiencies (up to 11% in fluid media). A further and pronounced increase in cultivation success was accomplished by the addition of cyclic AMP (cAMP), N-butyryl homoserine lactone, or N-oxohexanoyl-DL-homoserine lactone at a low concentration of 10 microM. The most effective inducer was cAMP, which led to cultivation efficiencies of up to 100% of total bacterial counts. From the highest positive dilutions of these latter MPN series, several strains were isolated in pure culture and one strain (G100) was used to study the physiological effect of cAMP. Dot blot hybridization revealed, however, that strain G100 represented only a small fraction of the total bacterial community. This points towards an inherent limitation of the MPN approach, which does not necessarily recover abundant species from highly diverse communities. Bacterial cells of strain G100 that were starved for 6 weeks attained a higher growth rate and a higher biomass yield when resuscitated in the presence of cAMP instead of AMP.

  20. Solid-Phase Synthesis of ɤ-Lactone and 1,2-Oxazine Derivatives and Their Efficient Chiral Analysis

    PubMed Central

    Krupkova, Sona; Aguete, Gonzalo Pazos; Kocmanova, Leona; Volna, Tereza; Grepl, Martin; Novakova, Lucie; Miller, Marvin John; Hlavac, Jan

    2016-01-01

    Derivatives of 3-methyl-3,6-dihydro-2H-1,2-oxazine-6-carboxylic acid prepared by regioselective hetero Diels-Alder reaction of arylnitroso compounds with sorbic acid were used for solid-phase synthesis of a library of derivatives that included modification of carboxylic group, dihydroxylation of double bond and cleavage of N-O bond. Derivatives of 2,3,4-trihydroxyhexanoic acid obtained from 3,6-dihydro-2H-1,2-oxazines after double bond dihydroxylation and N-O cleavage were used for simple and stereoselective formation of chiral lactones derived from 3,4-dihydroxydihydrofuran-2(3H)-one. The final compounds obtained as a mixture of stereoisomers were analyzed with use of chiral HPLC and SFC. HPLC analyses were not successful for all derivatives or required lengthy chromatography. On the other hand SFC afforded much shorter analyses and was effective for all studied derivatives. The method of synthesis and analysis is thus suitable for future study of stereoselective synthesis of lactones and other derivatives from single oxazine derivatives and application of high-throughput synthesis on solid-support and combinatorial chemistry. PMID:27893812

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

    PubMed

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

    2013-12-01

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

  2. Three-dimensional structure of the quorum-quenching N-acyl homoserine lactone hydrolase from Bacillus thuringiensis

    PubMed Central

    Liu, Dali; Lepore, Bryan W.; Petsko, Gregory A.; Thomas, Pei W.; Stone, Everett M.; Fast, Walter; Ringe, Dagmar

    2005-01-01

    The three-dimensional structure of the N-acyl-l-homoserine lactone hydrolase (AHL lactonase) from Bacillus thuringiensis has been determined, by using single-wavelength anomalous dispersion (SAD) phasing, to 1.6-Å resolution. AHLs are produced by many Gram-negative bacteria as signaling molecules used in quorum-sensing pathways that indirectly sense cell density and regulate communal behavior. Because of their importance in pathogenicity, quorum-sensing pathways have been suggested as potential targets for the development of novel therapeutics. Quorum-sensing can be disrupted by enzymes evolved to degrade these lactones, such as AHL lactonases. These enzymes are members of the metallo-β-lactamase superfamily and contain two zinc ions in their active sites. The zinc ions are coordinated to a number of ligands, including a single oxygen of a bridging carboxylate and a bridging water/hydroxide ion, thought to be the nucleophile that hydrolyzes the AHLs to ring-opened products, which can no longer act as quorum signals. PMID:16087890

  3. The molecular structure and catalytic mechanism of a quorum-quenching N-acyl-L-homoserine lactone hydrolase.

    PubMed

    Kim, Myung Hee; Choi, Won-Chan; Kang, Hye Ok; Lee, Jong Suk; Kang, Beom Sik; Kim, Kyung-Jin; Derewenda, Zygmunt S; Oh, Tae-Kwang; Lee, Choong Hwan; Lee, Jung-Kee

    2005-12-06

    In many Gram-negative bacteria, including a number of pathogens such as Pseudomonas aeruginosa and Erwinia carotovora, virulence factor production and biofilm formation are linked to the quorum-sensing systems that use diffusible N-acyl-L-homoserine lactones (AHLs) as intercellular messenger molecules. A number of organisms also contain genes coding for lactonases that hydrolyze AHLs into inactive products, thereby blocking the quorum-sensing systems. Consequently, these enzymes attract intense interest for the development of antiinfection therapies. However, the catalytic mechanism of AHL-lactonase is poorly understood and subject to controversy. We here report a 2.0-angstroms resolution structure of the AHL-lactonase from Bacillus thuringiensis and a 1.7-angstroms crystal structure of its complex with L-homoserine lactone. Despite limited sequence similarity, the enzyme shows remarkable structural similarities to glyoxalase II and RNase Z proteins, members of the metallo-beta-lactamase superfamily. We present experimental evidence that AHL-lactonase is a metalloenzyme containing two zinc ions involved in catalysis, and we propose a catalytic mechanism for bacterial metallo-AHL-lactonases.

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

    PubMed

    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.

  5. Aromatase inhibition by synthetic lactones and flavonoids in human placental microsomes and breast fibroblasts - A comparative study

    SciTech Connect

    Meeuwen, J.A. van Nijmeijer, S.; Mutarapat, T.; Ruchirawat, S.; Jong, P.C. de; Piersma, A.H.; Berg, M. van den

    2008-05-01

    Interference of exogenous chemicals with the aromatase enzyme can be useful as a tool to identify chemicals that could act either chemopreventive for hormone-dependent cancer or adverse endocrine disruptive. Aromatase is the key enzyme in the biosynthesis of steroids, as it converts androgens to estrogens. Certain flavonoids, plant derived chemicals, are known catalytic aromatase inhibitors. Various systems are in use to test aromatase inhibitory properties of compounds. Commonly used are microsomes derived from ovary or placental tissue characterized by high aromatase activity. To a lesser extent whole cell systems are used and specifically cell systems that are potential target tissue in breast cancer development. In this study aromatase inhibitory properties of fadrozole, 8-prenylnaringenin and a synthetic lactone (TM-7) were determined in human placental microsomes and in human primary breast fibroblasts. In addition, apigenin, chrysin, naringenin and two synthetic lactones (TM-8 and TM-9) were tested in human microsomes only. Comparison of the aromatase inhibitory potencies of these compounds between the two test systems showed that the measurement of aromatase inhibition in human placental microsomes is a good predictor of aromatase inhibition in human breast fibroblasts.

  6. Aromatase inhibition by synthetic lactones and flavonoids in human placental microsomes and breast fibroblasts--a comparative study.

    PubMed

    van Meeuwen, J A; Nijmeijer, S; Mutarapat, T; Ruchirawat, S; de Jong, P C; Piersma, A H; van den Berg, M

    2008-05-01

    Interference of exogenous chemicals with the aromatase enzyme can be useful as a tool to identify chemicals that could act either chemopreventive for hormone-dependent cancer or adverse endocrine disruptive. Aromatase is the key enzyme in the biosynthesis of steroids, as it converts androgens to estrogens. Certain flavonoids, plant derived chemicals, are known catalytic aromatase inhibitors. Various systems are in use to test aromatase inhibitory properties of compounds. Commonly used are microsomes derived from ovary or placental tissue characterized by high aromatase activity. To a lesser extent whole cell systems are used and specifically cell systems that are potential target tissue in breast cancer development. In this study aromatase inhibitory properties of fadrozole, 8-prenylnaringenin and a synthetic lactone (TM-7) were determined in human placental microsomes and in human primary breast fibroblasts. In addition, apigenin, chrysin, naringenin and two synthetic lactones (TM-8 and TM-9) were tested in human microsomes only. Comparison of the aromatase inhibitory potencies of these compounds between the two test systems showed that the measurement of aromatase inhibition in human placental microsomes is a good predictor of aromatase inhibition in human breast fibroblasts.

  7. Solvent-Free Lipase-Catalyzed Synthesis of Diacylgycerols as Low-Calorie Food Ingredients

    PubMed Central

    Vázquez, Luis; González, Noemí; Reglero, Guillermo; Torres, Carlos

    2016-01-01

    Problems derived from obesity and overweight have recently promoted the development of fat substitutes and other low-calorie foods. On the one hand, fats with short- and medium-chain fatty acids are a source of quick energy, easily hydrolyzable and hardly stored as fat. Furthermore, 1,3-diacylglycerols are not hydrolyzed to 2-monoacylglycerols in the gastrointestinal tract, reducing the formation of chylomicron and lowers the serum level of triacylglycerols by decreasing its resynthesis in the enterocyte. In this work, these two effects were combined to synthesize short- and medium-chain 1,3-diacylglycerols, leading to a product with great potential as for their low-calorie properties. Lipase-catalyzed transesterification reactions were performed between short- and medium-chain fatty acid ethyl esters and glycerol. Different variables were investigated, such as the type of biocatalyst, the molar ratio FAEE:glycerol, the adsorption of glycerol on silica gel, or the addition of lecithin. Best reaction conditions were evaluated considering the percentage of 1,3-DAG produced and the reaction rate. Except Novozym 435 (Candida antarctica), other lipases required the adsorption of glycerol on silica gel to form acylglycerols. Lipases that gave the best results with adsorption were Novozym 435 and Lipozyme RM IM (Rhizomucor miehei) with 52 and 60.7% DAG at 32 h, respectively. Because of its specificity for sn-1 and sn-3 positions, lipases leading to a higher proportion of 1,3-DAG vs. 1,2-DAG were Lipozyme RM IM (39.8 and 20.9%, respectively) and Lipase PLG (Alcaligenes sp.) (35.9 and 19.3%, respectively). By adding 1% (w/w) of lecithin to the reaction with Novozym 435 and raw glycerol, the reaction rate was considerably increased from 41.7 to 52.8% DAG at 24 h. PMID:26904539

  8. The Significance of Different Diacylgycerol Synthesis Pathways on Plant Oil Composition and Bioengineering

    PubMed Central

    Bates, Philip D.; Browse, John

    2012-01-01

    The unique properties of vegetable oils from different plants utilized for food, industrial feedstocks, and fuel is dependent on the fatty acid (FA) composition of triacylglycerol (TAG). Plants can use two main pathways to produce diacylglycerol (DAG), the immediate precursor molecule to TAG synthesis: (1) De novo DAG synthesis, and (2) conversion of the membrane lipid phosphatidylcholine (PC) to DAG. The FA esterified to PC are also the substrate for FA modification (e.g., desaturation, hydroxylation, etc.), such that the FA composition of PC-derived DAG can be substantially different than that of de novo DAG. Since DAG provides two of the three FA in TAG, the relative flux of TAG synthesis from de novo DAG or PC-derived DAG can greatly affect the final oil FA composition. Here we review how the fluxes through these two alternate pathways of DAG/TAG synthesis are determined and present evidence that suggests which pathway is utilized in different plants. Additionally, we present examples of how the endogenous DAG synthesis pathway in a transgenic host plant can produce bottlenecks for engineering of plant oil FA composition, and discuss alternative strategies to overcome these bottlenecks to produce crop plants with designer vegetable oil compositions. PMID:22783267

  9. Solvent-Free Lipase-Catalyzed Synthesis of Diacylgycerols as Low-Calorie Food Ingredients.

    PubMed

    Vázquez, Luis; González, Noemí; Reglero, Guillermo; Torres, Carlos

    2016-01-01

    Problems derived from obesity and overweight have recently promoted the development of fat substitutes and other low-calorie foods. On the one hand, fats with short- and medium-chain fatty acids are a source of quick energy, easily hydrolyzable and hardly stored as fat. Furthermore, 1,3-diacylglycerols are not hydrolyzed to 2-monoacylglycerols in the gastrointestinal tract, reducing the formation of chylomicron and lowers the serum level of triacylglycerols by decreasing its resynthesis in the enterocyte. In this work, these two effects were combined to synthesize short- and medium-chain 1,3-diacylglycerols, leading to a product with great potential as for their low-calorie properties. Lipase-catalyzed transesterification reactions were performed between short- and medium-chain fatty acid ethyl esters and glycerol. Different variables were investigated, such as the type of biocatalyst, the molar ratio FAEE:glycerol, the adsorption of glycerol on silica gel, or the addition of lecithin. Best reaction conditions were evaluated considering the percentage of 1,3-DAG produced and the reaction rate. Except Novozym 435 (Candida antarctica), other lipases required the adsorption of glycerol on silica gel to form acylglycerols. Lipases that gave the best results with adsorption were Novozym 435 and Lipozyme RM IM (Rhizomucor miehei) with 52 and 60.7% DAG at 32 h, respectively. Because of its specificity for sn-1 and sn-3 positions, lipases leading to a higher proportion of 1,3-DAG vs. 1,2-DAG were Lipozyme RM IM (39.8 and 20.9%, respectively) and Lipase PLG (Alcaligenes sp.) (35.9 and 19.3%, respectively). By adding 1% (w/w) of lecithin to the reaction with Novozym 435 and raw glycerol, the reaction rate was considerably increased from 41.7 to 52.8% DAG at 24 h.

  10. A Solvent-Free Baeyer-Villiger Lactonization for the Undergraduate Organic Laboratory: Synthesis of Gamma-T-Butyl-Epsilon-Caprolactone

    ERIC Educational Resources Information Center

    Esteb, John J.; Hohman, Nathan J.; Schlamandinger, Diana E.; Wilson, Anne M.

    2005-01-01

    The solvent-free or solid-state reaction systems like the Baeyer-Villiger rearrangement have become popular in the synthetic organic community and viable option for undergraduate laboratory series to reduce waste and cost and simplify reaction process. The reaction is an efficient method to transform ketones to esters and lactones.

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

    PubMed

    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.

  12. Simultaneous quantitative determination of 11 sesquiterpene lactones in Jerusalem artichoke (Helianthus tuberosus L.) leaves by ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

    PubMed

    Yuan, Xiaoyan; Yang, Qianxu

    2017-04-01

    A method of ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry was developed for the simultaneous quantification of 11 sesquiterpene lactones in 11 Jerusalem artichoke leaf samples harvested in a number of areas at different periods. The optimal chromatographic conditions were achieved on a ZORBAX Eclipse Plus C18 column (3.0 × 150 mm, 1.8 μm) with linear gradient elution of methanol and water in 8 min. Quantitative analysis was carried out under selective ion monitoring mode. All of the sesquiterpene lactones showed good linearity (R(2) ≥ 0.9949), repeatability (relative standard deviations < 4.66%), and intra- and interday precisions (relative standard deviations < 4.52%) with an accuracy of 95.24-104.84%. The recoveries measured at three concentration levels varied from 95.07 to 104.87% with relative standard deviations less than 4.9%. The limit of detection and limit of quantitation for this method were 0.89-5.05 and 1.12-44.33 ng/mL, respectively. The results showed that the contents of sesquiterpene lactones varied significantly in the Jerusalem artichoke leaf samples from different areas. Among them, the content of sesquiterpene lactones in the sample collected from Dalian, Liaoning province was the highest and the early flowering period was considered to be the optimal harvest time.

  13. Carbonylative enantioselective meso-desymmetrization of cis-epoxides to trans-β-lactones: effect of salen-ligand electronic variation on enantioselectivity.

    PubMed

    Mulzer, Michael; Lamb, Jessica R; Nelson, Zachary; Coates, Geoffrey W

    2014-09-07

    Carbonylation catalysts for the desymmetrization of meso-epoxides yielding enantioenriched trans-β-lactones are reported. Fine-tuning the electronic properties of the ligand further improved enantioselectivity. The sterics of the substrate dictated whether a given electronic variation decreased or increased enantioenrichment, revealing an unexpected relationship between the substrate's steric environment and the electronic nature of the optimal catalyst.

  14. Purification, crystallization and structural elucidation of d-galactaro-1,4-lactone cycloisomerase from Agrobacterium tumefaciens involved in pectin degradation

    PubMed Central

    Vetting, Matthew W.; Bouvier, Jason T.; Gerlt, John A.; Almo, Steven C.

    2016-01-01

    Pectin is found in the cell wall of plants and is often discarded as waste. A number of research groups are interested in redirecting this biomass waste stream for the production of fuel and bulk chemicals. The primary monomeric subunit of this polysaccharide is d-galacturonate, a six-carbon acid sugar that is degraded in a five-step pathway to central metabolic intermediates by some bacteria, including Agrobacterium tumefaciens. In the third step of the pathway, d-galactaro-1,4-lactone is converted to 2-keto-3-deoxy-l-threo-hexarate by a member of the mandelate racemase subgroup of the enolase superfamily with a novel activity for the superfamily. The 1.6 Å resolution structure of this enzyme was determined, revealing an overall modified (β/α)7β TIM-barrel domain, a hallmark of the superfamily. d-Galactaro-1,4-lactone was manually docked into the active site located at the interface between the N-terminal lid domain and the C-terminal barrel domain. On the basis of the position of the lactone in the active site, Lys166 is predicted to be the active-site base responsible for abstraction of the α proton. His296 on the opposite side of the active site is predicted to be the general acid that donates a proton to the β carbon as the lactone ring opens. The lactone ring appears to be oriented within the active site by stacking interactions with Trp298. PMID:26750482

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

    PubMed

    Veliz-Vallejos, Debora F; van Noorden, Giel E; Yuan, Mengqi; Mathesius, Ulrike

    2014-01-01

    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-independent mechanism.

  16. Modified N-acyl-homoserine lactones as chemical probes for the elucidation of plant-microbe interactions.

    PubMed

    Thomanek, Heike; Schenk, Sebastian T; Stein, Elke; Kogel, Karl-Heinz; Schikora, Adam; Maison, Wolfgang

    2013-09-25

    Gram-negative bacteria often use N-acyl-homoserine lactones (AHLs) as signal molecules to monitor their local population densities and to regulate gene-expression in a process called "Quorum Sensing" (QS). This cell-to-cell communication allows bacteria to adapt to environmental changes and to behave as multicellular communities. QS plays a key role in both bacterial virulence towards the host and symbiotic interactions with other organisms. Plants also perceive AHLs and respond to them with changes in gene expression or modifications in development. Herein, we report the synthesis of new AHL-derivatives for the investigation and identification of AHL-interacting proteins. We show that our new compounds are still recognised by different bacteria and that a novel biotin-tagged-AHL derivative interacts with a bacterial AHL receptor.

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

    DOEpatents

    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.

  18. Fluorinated amino-derivatives of the sesquiterpene lactone, parthenolide, as (19)f NMR probes in deuterium-free environments.

    PubMed

    Woods, James R; Mo, Huaping; Bieberich, Andrew A; Alavanja, Tanja; Colby, David A

    2011-11-24

    The design, synthesis, and biological activity of fluorinated amino-derivatives of the sesquiterpene lactone, parthenolide, are described. A fluorinated aminoparthenolide analogue with biological activity similar to the parent natural product was discovered, and its X-ray structure was obtained. This lead compound was then studied using (19)F NMR in the presence and absence of glutathione to obtain additional mechanism of action data, and it was found that the aminoparthenolide eliminates amine faster in the presence of glutathione than in the absence of glutathione. The exact changes in concentrations of fluorinated compound and amine were quantified by a concentration-reference method using (19)F NMR; a major benefit of applying this strategy is that no deuterated solvents or internal standards are required to obtain accurate concentrations. These mechanistic data with glutathione may contribute to the conversion of the amino-derivative to parthenolide, the active pharmacological agent, in glutathione-rich cancer cells.

  19. Possible Quorum Sensing in Marine Snow Bacteria: Production of Acylated Homoserine Lactones by Roseobacter Strains Isolated from Marine Snow

    PubMed Central

    Gram, Lone; Grossart, Hans-Peter; Schlingloff, Andrea; Kiørboe, Thomas

    2002-01-01

    We report here, for the first time, that bacteria associated with marine snow produce communication signals involved in quorum sensing in gram-negative bacteria. Four of 43 marine microorganisms isolated from marine snow were found to produce acylated homoserine lactones (AHLs) in well diffusion and thin-layer chromatographic assays based on the Agrobacterium tumefaciens reporter system. Three of the AHL-producing strains were identified by 16S ribosomal DNA gene sequence analysis as Roseobacter spp., and this is the first report of AHL production by these α-Proteobacteria. It is likely that AHLs in Roseobacter species and other marine snow bacteria govern phenotypic traits (biofilm formation, exoenzyme production, and antibiotic production) which are required mainly when the population reaches high densities, e.g., in the marine snow community. PMID:12147515

  20. Optical sensor of anionic surfactants using solid-phase extraction with a lactone-form rhodamine B membrane.

    PubMed

    Masadome, Takashi; Akatsu, Motoo

    2008-06-01

    An optical sensor for the detection of anionic surfactants was developed. The optical sensing membrane is a 2-nitrophenyloctyl ether-plasticized poly(vinyl chloride) membrane incorporating a lactone-form Rhodamine B (L-RB). The response of the optical membrane to anionic surfactants was a result of the ion-pair coextraction of an anionic surfactant and a proton into the PVC membrane. The L-RB forms an ion associate with the extracted anionic surfactant; simultaneously, the formed L-RB ion associate is accompanied by a spectral change. Namely, the extracted anionic surfactant changes the color of the membrane from light pink to dark pink (absorption maximum; 558 nm). The optical membrane responds to anionic surfactants, such as dodecylbenzenesulfonate, dodecylsulfate and di-2-ethylhexyl sulfosuccinate in the concentration range from 1 to 50 microM.

  1. Identification of sesquiterpene lactones in the Bryophyta (mosses) Takakia: Takakia species are closely related chemically to the Marchantiophyta (liverworts).

    PubMed

    Asakawa, Yoshinori; Nii, Kaeko; Higuchi, Masanobu

    2015-01-01

    Takakia lepidozioides has been considered to be the most primitive liverwort morphologically and classified initially in the Marchantiophyta (liverworts). However, the Takakia have been reclassified from liverworts to mosses on the basis of the similarity of the male sporophyte of T. ceratophylla to that of some mosses. Reinvestigation of secondary metabolites of fresh T. lepidozioides resulted in identification of eudesmane-type sesquiterpene lactones and hydrocarbon that are significant chemical markers of several liverworts. T. lepidozioides also produces a small amount of hop-22(29)-ene, together with coumarin, which produce the characteristic odor of T. lepidozioides, and 1,4-hydroquinone; these are the predominant volatile components, whereas dihydrocoumarin, 1,4-benzoquinone, dihydrobenzofuran, α-asarone and α-tocopherol are minor components. These chemical results indicated that T. lepidozioides is more closely related to the Marchantiophyta than the Bryophyta. T. lepidozioides is morphologically similar to the liverwort Haplomitrium species. However, both species are totally different chemically.

  2. Fluorinated Amino-Derivatives of the Sesquiterpene Lactone, Parthenolide, as 19F NMR Probes in Deuterium-Free Environments

    PubMed Central

    Woods, James R.; Mo, Huaping; Bieberich, Andrew A.; Alavanja, Tanja; Colby, David A.

    2011-01-01

    The design, synthesis, and biological activity of fluorinated amino-derivatives of the sesquiterpene lactone, parthenolide, are described. A fluorinated aminoparthenolide analogue with biological activity similar to the parent natural product was discovered, and its X-ray structure was obtained. This lead compound was then studied using 19F NMR in the presence and absence of glutathione to obtain additional mechanism of action data, and it was found that the aminoparthenolide eliminates amine faster in the presence of glutathione than in the absence of glutathione. The exact changes in concentrations of fluorinated compound and amine were quantified by a concentration-reference method using 19F NMR; a major benefit of applying this strategy is that no deuterated solvents or internal standards are required to obtain accurate concentrations. These mechanistic data with glutathione may contribute to the conversion of the amino-derivative to parthenolide, the active pharmacological agent, in glutathione-rich cancer cells. PMID:22029741

  3. Draft genome sequence of Citrobacter freundii strain ST2, a γ-proteobacterium that produces N-acylhomoserine lactones.

    PubMed

    Wang, Yan; Zhou, Jin

    2015-12-01

    Citrobacter freundii strain ST2, isolated from the algae bloom sample, possesses an N-acylhomoserine lactone (AHL) production activity that secretes short-chain AHL molecules. In this study, we sequenced the complete genome of C. freundii strain ST2 to understand the molecular regulation of the AHL system and to search for the AHL gene in this bacterium. The results show that the genome size is 4.89 Mb with a G + C content of 51.96%. 4626 function proteins were predicted and 3647 proteins were assigned to COG functional categories. A predicted AHL-coding gene LuxR was found at contig 4 and the length was 1541 bp. The strain temporary deposited at Shenzhen Public Platform of Screening & Application of Marine Microbial Resources (Shenzhen, China), and the genome sequence can be accessed at GenBank under the accession no. LJSQ00000000.

  4. Scapiformolactones A-I: germacrane sesquiterpenoids with an unusual Δ3-15,6-lactone moiety from Salvia scapiformis.

    PubMed

    Lai, Yongji; Xue, Yongbo; Zhang, Mengke; Zhang, Jinwen; Tang, Wei; Liu, Junjun; Lei, Liang; Yan, Juming; Luo, Zengwei; Zuo, Jianping; Li, Yan; Yao, Guangmin; Zhang, Yonghui

    2013-12-01

    Nine germacrane sesquiterpenoids with an unusual Δ(3)-15,6-lactone moiety, scapiformolactones A-I (1-9), and one known seco-germacrane sesquiterpenoid, 3,7,11-trimethyldodeca-l,6,9-triene-3,11-diol (10), were isolated from whole plants of Salvia scapiformis Hance. Their structures were elucidated by spectroscopic methods including HR-ESIMS, IR, UV, NMR, and CD, as well as by quantum mechanical calculations and chemical transformations. Structures of compounds 1-3 were also confirmed by single-crystal X-ray diffraction analysis. Six germacrane 6,15-diol derivatives (11-16) were obtained by chemical transformation. Compounds 1-9 and 11-16 were evaluated for their in vitro immunomodulatory effects on T and B cells, as well as their in vitro cytotoxicity against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7, and SW480.

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

    PubMed

    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.

  6. Preparative isolation and purification of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. by high-speed counter-current chromatography.

    PubMed

    Yan, Guilong; Ji, Lilian; Luo, Yuming; Hu, Yonghong

    2012-07-27

    A high-speed counter-current chromatography (HSCCC) method was established for the preparative separation of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:4:2:3, v/v/v/v) was selected. From 540 mg of the n-butanol fraction of Eupatorium lindleyanum DC., 10.8 mg of 3β-hydroxy-8β-[4'-hydroxytigloyloxy]-costunolide, 17.9 mg of eupalinolide A and 19.3 mg of eupalinolide B were obtained in a one-step HSCCC separation, with purities of 91.8%, 97.9% and 97.1%, respectively, as determined by HPLC. Their structures were further identified by ESI-MS and ¹H-NMR.

  7. Dehalogenation Activity of Selected Fungi Toward δ-Iodo-γ-Lactone Derived from trans,trans-Farnesol.

    PubMed

    Gliszczyńska, Anna; Gładkowski, Witold; Świtalska, Marta; Wietrzyk, Joanna; Szumny, Antoni; Gębarowska, Elżbieta; Wawrzeńczyk, Czesław

    2016-04-01

    Time-course of biotransformation of racemic trans-4-((E)-4',8'-dimethylnona-3',7'-dien-1-yl)-5-iodomethyl-4-methyldihydrofuran-2-one (1) in fungal and yeast cultures was investigated. In these conditions, the substrate 1 was enantioselectively dehalogenated yielding 4-((E)-4',8'-dimethylnona-3',7'-dien-1-yl)-4-methyl-5-methylenedihydrofuran-2-one (2) and its structure was established based on the spectroscopic data. The most effective biocatalyst used was Didymosphaeria igniaria, which catalyzed the process with highest rate and enantioselectivity (ee of product = 76%). The antiproliferative activity of δ-iodo-γ-lactone 1, product of its biotransformation 2, and starting substrate (farnesol) were evaluated toward two cancer cell lines: A549 (human lung adenocarcinoma) and HL-60 (human promyelocytic leukemia).

  8. The quorum-sensing molecules farnesol/homoserine lactone and dodecanol operate via distinct modes of action in Candida albicans.

    PubMed

    Hall, Rebecca A; Turner, Kara J; Chaloupka, James; Cottier, Fabien; De Sordi, Luisa; Sanglard, Dominique; Levin, Lonny R; Buck, Jochen; Mühlschlegel, Fritz A

    2011-08-01

    Living as a commensal, Candida albicans must adapt and respond to environmental cues generated by the mammalian host and by microbes comprising the natural flora. These signals have opposing effects on C. albicans, with host cues promoting the yeast-to-hyphal transition and bacteria-derived quorum-sensing molecules inhibiting hyphal development. Hyphal development is regulated through modulation of the cyclic AMP (cAMP)/protein kinase A (PKA) signaling pathway, and it has been postulated that quorum-sensing molecules can affect filamentation by inhibiting the cAMP pathway. Here, we show that both farnesol and 3-oxo-C(12)-homoserine lactone, a quorum-sensing molecule secreted by Pseudomonas aeruginosa, block hyphal development by affecting cAMP signaling; they both directly inhibited the activity of the Candida adenylyl cyclase, Cyr1p. In contrast, the 12-carbon alcohol dodecanol appeared to modulate hyphal development and the cAMP signaling pathway without directly affecting the activity of Cyr1p. Instead, we show that dodecanol exerted its effects through a mechanism involving the C. albicans hyphal repressor, Sfl1p. Deletion of SFL1 did not affect the response to farnesol but did interfere with the response to dodecanol. Therefore, quorum sensing in C. albicans is mediated via multiple mechanisms of action. Interestingly, our experiments raise the possibility that the Burkholderia cenocepacia diffusible signal factor, BDSF, also mediates its effects via Sfl1p, suggesting that dodecanol's mode of action, but not farnesol or 3-oxo-C(12)-homoserine lactone, may be used by other quorum-sensing molecules.

  9. L-galactono-gamma-lactone dehydrogenase aand vitamin C content in fresh-cut potatoes stored under controlled atmospheres.

    PubMed

    Tudela, Juan Antonio; Hernández, José Antonio; Gil, María Isabel; Espín, Juan Carlos

    2003-07-16

    L-galactono-gamma-lactone dehydrogenase (GLDH) activity and vitamin C content as ascorbic acid (AA) plus dehydroascorbic acid (DHA) were evaluated in five potato tuber cultivars (Agata, Altesse, Franceline, Manon, and Monalisa). The effect of fresh-cutting and subsequent refrigerated storage of Manon potato under different atmospheres (air, 20% CO(2) + air, 100% N(2), and vacuum packaging) on GLDH activity and vitamin C content was also determined. GLDH from the five potato tuber cultivars showed typical inhibition kinetics by high substrate concentration in the synthesis of AA from its physiological precursor L-galactonic acid-gamma-lactone (GL). GLDH activity was not correlated with the corresponding vitamin C content in any potato tuber cultivar. GLDH from all the cultivars presented a major isoform with isoelectric point (IEP) 5, which changed to IEP = 4.3 after minimal processing. In addition, the GLDH-catalyzed synthesis of AA by the new isoform showed typical Michaelis kinetics, in which the enzyme became more efficient to catalyze the reaction. Whether the change in the isoform pattern was due to either post-translational modifications or de novo synthesis of a new isoenzyme remains unanswered. Fresh-cutting increased GLDH activity from 4.7-fold (vacuum packaging) to 11-fold (air) after 6 days. In addition, 100% of vitamin C content was retained in air and decreased in the rest of atmospheres after this storage period, following the sequence vacuum packaging (89%) > 100% N(2) (78%) > 20% CO(2) + air (63%). This tendency was correlated with the corresponding GLDH activity detected in each storage atmosphere, except in the case of 20% CO(2) + air. Vacuum packaging proved to be the best storage condition, because fresh-cut potatoes did not turn brown and retained 89% of initial vitamin C content.

  10. A novel lactone-forming carboxylesterase: molecular identification of a tuliposide A-converting enzyme in tulip.

    PubMed

    Nomura, Taiji; Ogita, Shinjiro; Kato, Yasuo

    2012-06-01

    Tuliposides, the glucose esters of 4-hydroxy-2-methylenebutanoate and 3,4-dihydroxy-2-methylenebutanoate, are major secondary metabolites in tulip (Tulipa gesneriana). Their lactonized aglycons, tulipalins, function as defensive chemicals due to their biological activities. We recently found that tuliposide-converting enzyme (TCE) purified from tulip bulbs catalyzed the conversion of tuliposides to tulipalins, but the possibility of the presence of several TCE isozymes was raised: TCE in tissues other than bulbs is different from bulb TCE. Here, to prove this hypothesis, TCE was purified from petals, which have the second highest TCE activity after bulbs. The purified enzyme, like the bulb enzyme, preferentially accepted tuliposides as substrates, with 6-tuliposide A the best substrate, which allowed naming the enzyme tuliposide A-converting enzyme (TCEA), but specific activity and molecular mass differed between the petal and bulb enzymes. After peptide sequencing, a novel cDNA (TgTCEA) encoding petal TCEA was isolated, and the functional characterization of the recombinant enzyme verified that TgTCEA catalyzes the conversion of 6-tuliposide A to tulipalin A. TgTCEA was transcribed in all tulip tissues but not in bulbs, indicating the presence of a bulb-specific TgTCEA, as suggested by the distinct enzymatic characters between the petal and bulb enzymes. Plastidial localization of TgTCEA enzyme was revealed, which allowed proposing a cytological mechanism of TgTCE-mediated tulipalin formation in the tulip defensive strategy. Site-directed mutagenesis of TgTCEA suggested that the oxyanion hole and catalytic triad characteristic of typical carboxylesterases are essential for the catalytic process of TgTCEA enzyme. To our knowledge, TgTCEA is the first identified member of the lactone-forming carboxylesterases, specifically catalyzing intramolecular transesterification.

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

    PubMed Central

    Zhao, Qian; Zhang, Chao; Jia, Zhenhua; Huang, Yali; Li, Haili; Song, Shuishan

    2015-01-01

    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. PMID:25628641

  12. A Review on the Toxicity and Non-Target Effects of Macrocyclic Lactones in Terrestrial and Aquatic Environments

    PubMed Central

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

    2012-01-01

    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

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

    PubMed Central

    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

  14. A Novel Lactone-Forming Carboxylesterase: Molecular Identification of a Tuliposide A-Converting Enzyme in Tulip1[W

    PubMed Central

    Nomura, Taiji; Ogita, Shinjiro; Kato, Yasuo

    2012-01-01

    Tuliposides, the glucose esters of 4-hydroxy-2-methylenebutanoate and 3,4-dihydroxy-2-methylenebutanoate, are major secondary metabolites in tulip (Tulipa gesneriana). Their lactonized aglycons, tulipalins, function as defensive chemicals due to their biological activities. We recently found that tuliposide-converting enzyme (TCE) purified from tulip bulbs catalyzed the conversion of tuliposides to tulipalins, but the possibility of the presence of several TCE isozymes was raised: TCE in tissues other than bulbs is different from bulb TCE. Here, to prove this hypothesis, TCE was purified from petals, which have the second highest TCE activity after bulbs. The purified enzyme, like the bulb enzyme, preferentially accepted tuliposides as substrates, with 6-tuliposide A the best substrate, which allowed naming the enzyme tuliposide A-converting enzyme (TCEA), but specific activity and molecular mass differed between the petal and bulb enzymes. After peptide sequencing, a novel cDNA (TgTCEA) encoding petal TCEA was isolated, and the functional characterization of the recombinant enzyme verified that TgTCEA catalyzes the conversion of 6-tuliposide A to tulipalin A. TgTCEA was transcribed in all tulip tissues but not in bulbs, indicating the presence of a bulb-specific TgTCEA, as suggested by the distinct enzymatic characters between the petal and bulb enzymes. Plastidial localization of TgTCEA enzyme was revealed, which allowed proposing a cytological mechanism of TgTCE-mediated tulipalin formation in the tulip defensive strategy. Site-directed mutagenesis of TgTCEA suggested that the oxyanion hole and catalytic triad characteristic of typical carboxylesterases are essential for the catalytic process of TgTCEA enzyme. To our knowledge, TgTCEA is the first identified member of the lactone-forming carboxylesterases, specifically catalyzing intramolecular transesterification. PMID:22474185

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

    PubMed

    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.

  16. Ytterbium(III) porpholactones: β-lactonization of porphyrin ligands enhances sensitization efficiency of lanthanide near-infrared luminescence.

    PubMed

    Ke, Xian-Sheng; Yang, Bo-Yan; Cheng, Xin; Chan, Sharon Lai-Fung; Zhang, Jun-Long

    2014-04-07

    The near-infrared (NIR) luminescence efficiency of lanthanide complexes is largely dependent on the electronic and photophysical properties of antenna ligands. Although porphyrin ligands are efficient sensitizers of lanthanide NIR luminescence, non-pyrrolic porphyrin analogues, which have unusual symmetry and electronic states, have been much less studied. In this work, we used porpholactones, a class of β-pyrrolic-modified porphyrins, as ligands and investigated the photophysical properties of lanthanide porpholactones Yb-1 a-5 a. Compared with Yb porphyrin complexes, the porpholactone complexes displayed remarkable enhancement of NIR emission (50-120 %). Estimating the triplet-state levels of porphyrin and porpholactone in Gd complexes revealed that β-lactonization of porphyrinic ligands lowers the ligand T1 state and results in a narrow energy gap between this state and the lowest excited state of Yb(3+) . Transient absorption spectra showed that Yb(III) porpholactone has a longer transient decay lifetime at the Soret band than the porphyrin analogue (30.8 versus 17.0 μs). Thus, the narrower energy gap and longer lifetime arising from β-lactonization are assumed to enhance NIR emission of Yb porpholactones. To demonstrate the potential applications of Yb porpholactone, a water-soluble Yb bioprobe was constructed by conjugating glucose to Yb-1 a. Interestingly, the NIR emission of this Yb porpholactone could be specifically switched on in the presence of glucose oxidase and then switched off by addition of glucose. This is the first demonstration that non-pyrrolic porphyrin ligands enhance the sensitization efficiency of lanthanide luminescence and also display switchable NIR emission in the region of biological analytes (800-1400 nm).

  17. In vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg population.

    PubMed

    Foster, Joyce G; Cassida, Kimberly A; Turner, Kenneth E

    2011-08-25

    The anthelmintic activity of chicory (Cichorium intybus L.) herbage has been attributed to sesquiterpene lactones. Chicory leaves contain significant amounts of lactucin (LAC), 8-deoxylactucin (DOL), and lactucopicrin (LPIC), but the proportions of these three sesquiterpene lactones vary among forage chicory cultivars. To determine whether the individual compounds differ in anthelmintic activity, we prepared sesquiterpene lactone-enriched extracts from leaves of two forage chicory cultivars, 'Grasslands Puna' (Puna) and 'Forage Feast', and tested their effects on the hatching of a predominantly Haemonchus contortus egg population. The dominant constituents in the Puna and Forage Feast extracts were DOL and LAC, respectively; LPIC concentrations in the two extracts were similar. Extracts from both cultivars inhibited egg hatching at all concentrations tested (P<0.001), but there were significant differences in egg responses to the two extracts (P<0.001). With Puna, egg hatching decreased sharply in a linear fashion when the combined LAC, DOL, and LPIC concentrations ranged from 0 to 5.0mg/ml. A biphasic effect on egg hatching occurred with the Forage Feast extract. The fraction of eggs that hatched decreased gradually to 65% as the sesquiterpene lactone concentrations increased from 0 to 6.7 mg/ml. Treatment with higher concentrations resulted in a sharp decline in egg hatchability. Concentrations of sesquiterpene lactones required for 50% lethality were determined by probit dose-effect analysis to be 2.6 mg/ml (95% confidence interval: 2.4-2.8 mg/ml) for the Puna extract and 6.4 mg/ml (95% confidence interval: 5.9-7.2mg/ml) for the Forage Feast extract (P<0.0001). These concentrations provided 1.3 and 1.5mg/ml of DOL and 0.8 and 3.9 mg/ml of LAC for Puna and Forage Feast extracts, respectively. Results suggest that LAC has minimal effect on egg hatching and that DOL or other constituent(s) in the extracts is inhibitory. Quantitative analyses of free sesquiterpene

  18. Lewis acid promoted reactions of ethenetricarboxylates with allenes: synthesis of indenes and gamma-lactones via conjugate addition/cyclization reaction.

    PubMed

    Yamazaki, Shoko; Yamamoto, Yuko; Fukushima, Yugo; Takebayashi, Masachika; Ukai, Tetsuma; Mikata, Yuji

    2010-08-06

    Indenes are important core structures in organic chemistry. Few simple arylallenes have been used to construct indene skeletons by Friedel-Crafts reaction. Lewis acid catalyzed reaction of ethenetricarboxylates 1 and arylallenes has been examined in this study. The reaction of arylallenes and ethenetricarboxylate triesters with SnCl(4) gave indene derivatives efficiently, via a conjugate addition/Friedel-Crafts cyclization reaction. On the other hand, the reactions of 1,1-diethyl 2-hydrogen ethenetricarboxylate and arylallenes or alkylallenes with SnCl(4) at -78 degrees C or room temperature and subsequent treatment with Et(3)N gave gamma-lactones. The reactions of triethyl ethenetricarboxylate and 1,1-dialkylallenes with SnCl(4) at room temperature also gave gamma-lactones.

  19. Biosynthesis of Ascorbic Acid in Kidney Bean. l-Galactono-γ-Lactone Dehydrogenase Is an Intrinsic Protein Located at the Mitochondrial Inner Membrane1

    PubMed Central

    Siendones, Emilio; González-Reyes, José A.; Santos-Ocaña, Carlos; Navas, Plácido; Córdoba, Francisco

    1999-01-01

    Hypocotyls of kidney beans (Phaseolus vulgaris L.) accumulated ascorbate after preincubation with a number of possible precursors, mainly l-galactono-γ-lactone (l-GL) and l-gulono-γ-lactone. The increase in the intracellular ascorbate concentration was parallel to the high stimulation of the l-GL dehydrogenase (l-GLD) activity measured in vitro using l-GL as a substrate and cytochrome c as an electron acceptor. Cell fractionation using a continuous linear Percoll gradient demonstrated that l-GLD is associated with mitochondria; therefore, pure mitochondria were isolated and subjected to detergent treatment to separate soluble from membrane-linked proteins. l-GLD activity was mainly associated with the detergent phase, suggesting that a membrane-intrinsic protein is responsible for the ascorbic acid biosynthetic activity. Subfractionation of mitochondria demonstrated that l-GLD is located at the inner membrane. PMID:10398727

  20. Replacement of the lactone moiety on podophyllotoxin and steganacin analogues with a 1,5-disubstituted 1,2,3-triazole via ruthenium-catalyzed click chemistry.

    PubMed

    Imperio, Daniela; Pirali, Tracey; Galli, Ubaldina; Pagliai, Francesca; Cafici, Laura; Canonico, Pier Luigi; Sorba, Giovanni; Genazzani, Armando A; Tron, Gian Cesare

    2007-11-01

    Steganacin and podophyllotoxin are two naturally occurring lignans first isolated from plant sources, which share the capability to disrupt tubulin assembly. Although not strictly essential for its activity, the lactone ring on both structures represents Achilles' heel, as it is a potential site of metabolic degradation and epimerization on its C2 carbon brings about a significant loss in potency. In the present manuscript, we have used the ruthenium-catalyzed [3+2] azide-alkyne cycloaddition, a click-chemistry reaction, to replace the lactone ring with a 1,5-disubstituted triazole in few synthetic steps. The compounds were cytotoxic, although to a lesser degree compared to podophyllotoxin, while retaining antitubulin activity. The present structures might therefore represent a good platform for the fast generation of metabolically stable compounds with few stereogenic centers that might be of value from a medicinal chemistry point of view.

  1. Halocarbocyclization Entry into the Oxabicyclo[4.3.1]decyl Exomethylene-δ-Lactone Cores of Linearifolin and Zaluzanin A - Exploiting Combinatorial Catalysis

    PubMed Central

    Ginotra, Sandeep K.; Friest, Jacob A.; Berkowitz, David B.

    2012-01-01

    A streamlined entry into the sesquiterpene lactones (SQL) cores of linearifolin and zaluzanin A is described. Stereochemistry is controlled through transformations uncovered by ISES (In-Situ-Enzymatic-Screening). Absolute stereochemistry derives from kinetic resolution of 5-benzyloxypentene-1,2-oxide, utilizing a β-pinene-derived-Co(III)-salen. Relative stereochemistry (1,3-cis-fusion)is set via formal halometalation/carbocyclization, mediated by [Rh(O2CC3F7)2]2/LiBr. Subsequent ring-closing metathesis (RCM-Grubbs II) yields the title exomethylene-δ-lactone SQL-cores. In complementary fashion, RCM with Grubbs-I catalyst provides the oxabicyclo[3.3.1]nonyl-core of xerophilusin R and zinagrandinolide. PMID:22316136

  2. Indium-Catalyzed Amide Allylation of N-Carbonyl Imides: Formation of Azaspiro-γ-lactones via Ring Opening-Reclosure.

    PubMed

    Sengoku, Tetsuya; Murata, Yusuke; Aso, Yuwa; Kawakami, Ai; Inuzuka, Toshiyasu; Sakamoto, Masami; Takahashi, Masaki; Yoda, Hidemi

    2015-12-04

    A novel and facile synthesis of azaspiro-γ-lactones with a methylene-lactam framework from N-carbonyl imides is described. Mechanistic investigations provide evidence for a two-step reaction process involving ZnCl(2)-promoted addition of β-amido allylindium species followed by an unexpectedly molecular-sieves-mediated ring opening-reclosure concomitantly with the loss of an N-carbonyl unit.

  3. Complete Genome Sequence of Chryseobacterium sp. Strain StRB126, an N-Acylhomoserine Lactone-Degrading Bacterium Isolated from Potato Root

    PubMed Central

    Wang, Wen-Zhao; Someya, Nobutaka; Ikeda, Tsukasa

    2014-01-01

    Chryseobacterium sp. strain StRB126 was isolated from a potato root and showed N-acylhomoserine lactone-degrading activity. Here, we present the complete 5,503,743-bp genome sequence of StRB126, which has a G+C content of 35.6% and carries 4,828 protein-coding genes, six rRNA operons, and 80 tRNA genes. PMID:25291777

  4. Octanoyl-Homoserine Lactone Is the Cognate Signal for Burkholderia mallei BmaR1-BmaI1 Quorum Sensing

    DTIC Science & Technology

    2007-07-01

    Burkholderia species, the Burkholderia cepacia complex. In Burkholderia cenocepacia, there are two luxI-luxR homolog pairs. The primary product of...transcription factor. Mol. Microbiol. 59:602–609. 22. Lewenza, S., B. Conway, E. P. Greenberg, and P. A. Sokol. 1999. Quorum sensing in Burkholderia cepacia ...acyl-L-homoserine lactone production by CepR in Burkholderia cepacia . J. Bacteriol. 183:2212–2218. 24. Lumjiaktase, P., S. P. Diggle, S. Loprasert, S

  5. Unravelling the genome of long chain N-acylhomoserine lactone-producing Acinetobacter sp. strain GG2 and identification of its quorum sensing synthase gene

    PubMed Central

    How, Kah Yan; Hong, Kar-Wai; Sam, Choon-Kook; Koh, Chong-Lek; Yin, Wai-Fong; Chan, Kok-Gan

    2015-01-01

    Myriad proteobacteria use N-acyl homoserine lactone (AHL) molecules as quorum sensing (QS) signals to regulate different physiological functions, including virulence, antibiotic production, and biofilm formation. Many of these proteobacteria possess LuxI/LuxR system as the QS mechanism. Recently, we reported the 3.89 Mb genome of Acinetobacter sp. strain GG2. In this work, the genome of this long chain AHL-producing bacterium was unravelled which led to the molecular characterization of luxI homologue, designated as aciI. This 552 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was ∼20.5 kDa and is highly similar to several autoinducer proteins of LuxI family among Acinetobacter species. To verify the AHL synthesis activity of this protein, high-resolution liquid chromatography–mass spectrometry analysis revealed the production of 3-oxo-dodecanoyl-homoserine lactone and 3-hydroxy-dodecanoyl-homoserine lactone from induced E. coli harboring the recombinant AciI. Our data show for the first time, the cloning and characterization of the luxI homologue from Acinetobacter sp. strain GG2, and confirmation of its AHLs production. These data are of great significance as the annotated genome of strain GG2 has provided a valuable insight in the study of autoinducer molecules and its roles in QS mechanism of the bacterium. PMID:25926817

  6. Vitamin B12[c-lactone], a biologically inactive corrinoid compound, occurs in cultured and dried lion's mane mushroom (Hericium erinaceus) fruiting bodies.

    PubMed

    Teng, Fei; Bito, Tomohiro; Takenaka, Shigeo; Yabuta, Yukinori; Watanabe, Fumio

    2014-02-19

    This study determined the vitamin B12 content of the edible medicinal mushroom Hericium erinaceus, lion's mane mushroom fruiting body, using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.04-0.36 μg/100 g dry weight) of vitamin B12 were found in most of the dried mushroom samples, and two samples contained slightly higher levels (0.56 and 1.04 μg/100 g dry weight, respectively) of vitamin B12. We purified the corrinoid compounds from the extracts of dried lion's mane mushroom fruiting bodies using an immunoaffinity column and identified them as vitamin B12 or vitamin B12[c-lactone] (or both) based on LC/ESI-MS/MS chromatograms. This is the first report on an unnatural corrinoid, vitamin B12[c-lactone], occurring in foods. Vitamin B12[c-lactone] was simple to produce during incubation of authentic vitamin B12 and chloramine-T, an antimicrobial agent, at varying pH values (3.0-7.0) and was completely inactive in the vitamin B12-dependent bacteria that are generally used in vitamin B12 bioassays.

  7. Asymmetric Synthesis, Structure, and Reactivity of Unexpectedly Stable Spiroepoxy-β-Lactones Including Facile Conversion to Tetronic Acids: Application to (+)-Maculalactone A

    PubMed Central

    Duffy, Richard J.; Morris, Kay A.; Vallakati, Ravikrishna; Zhang, Wei; Romo, Daniel

    2009-01-01

    A novel class of small spirocyclic heterocycles, spiroepoxy-β-lactones (1,4-dioxaspiro[2.3]-hexan-5-ones), is described that exhibit a number of interesting reactivity patterns. These spiroheterocycles, including an optically active series, are readily synthesized by epoxidation of ketene dimers (4-alkylidene-2-oxetanones) available from homo- or heteroketene dimerization. An analysis of bond lengths in these systems by X-ray crystallography and comparison to data for known spirocycles and those determined computationally, suggest that anomeric effects in these systems may be more pronounced due to their rigidity and may contribute to their surprising stability. The synthetic utility of spiroepoxy-β-lactones was explored and one facile rearrangement identified under several conditions provides a 3-step route from acid chlorides to optically active tetronic acids, ubiquitous heterocycles in bioactive natural products. The addition of various nucleophiles to these spirocycles leads primarily to addition at C5 and C2. The utility of an optically active spiroepoxy-β-lactone was demonstrated in the concise, enantioselective synthesis of the anti-fouling agent, (+)-maculalactone A, which proceeds in 5 steps from hydrocinnamoyl chloride by way of a tetronic acid intermediate. PMID:19453152

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

    PubMed

    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.

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

    PubMed

    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

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

    PubMed Central

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

    2015-01-01

    Abstract 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 Fe3+ (70%); however, it decreased to 45% as concentration of Fe3+ 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

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

    PubMed Central

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

    2008-01-01

    Summary 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. PMID:21261861

  12. [Synthesis of signaling N-acyl-homoserine-lactones participating in quorum sensing in rhizosphere and soil bacteria Pseudomonas and Xanthomonas].

    PubMed

    Khmel', I A; Veselova, M A; Metlitskaia, A Z; Klein, S; Lipasova, V A; Maiatskaia, A V; Chernin, L S

    2002-04-01

    Signaling molecules assigned to N-acyl-homoserine-lactones (AHL) serve as autoinducers for the genes controlling the quorum sensing regulatory system. In many gram-negative bacteria, AHL are the key factors responsible for density-dependent regulation of exoenzyme and secondary metabolite production; they also participate in interaction between bacteria and higher organisms. The soil and rhisosphere bacteria Pseudomonas and Xanthomonas from different geographical zones of Russia and the former USSR were analyzed for the presence of the AHL producers. Screening was conducted by using a test system based on the mutant strain Chromobacterium violaceum, which was unable to synthesize AHL but produced a pigment violacein in the presence of exogenous AHL. The AHL-like compounds proved to be formed by 9.7% of the studied bacteria. Various Pseudomonas species differed in the capacity to synthesize this compounds. In at least a half of the isolated P. aureofaciens and P. aeruginosa, an intense AHL production was observed, whereas the AHL-producers were far less frequent among the P. fluorescens, P. chlororaphis, P. lemonnieri, P. geniculata, and P. putida. None of the 41 Xanthomonas maltophilia strains examined synthesized AHL.

  13. Non-antibiotic quorum sensing inhibitors acting against N-acyl homoserine lactone synthase as druggable target

    PubMed Central

    Chang, Chien-Yi; Krishnan, Thiba; Wang, Hao; Chen, Ye; Yin, Wai-Fong; Chong, Yee-Meng; Tan, Li Ying; Chong, Teik Min; Chan, Kok-Gan

    2014-01-01

    N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography–mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach. PMID:25430794

  14. Cytotoxic and pro-apoptotic activities of cynaropicrin, a sesquiterpene lactone, on the viability of leukocyte cancer cell lines.

    PubMed

    Cho, Jae Youl; Kim, Ae Ra; Jung, Jee H; Chun, Taehoon; Rhee, Man Hee; Yoo, Eun Sook

    2004-05-25

    Cynaropicrin, a sesquiterpene lactone from Saussurea lappa, has been reported to possess immunomodulatory effects on cytokine release, nitric oxide production and immunosuppressive effects. In this study, we have examined cytotoxic effect of cynaropicrin against several types of cell lines such as macrophages, eosinophils, fibroblasts and lymphocytes. Cynaropicrin potently inhibited the proliferation of leukocyte cancer cell lines, such as U937, Eol-1 and Jurkat T cells, but some other cells such as Chang liver cells and human fibroblast cell lines were not strongly suppressed by cynaropicrin treatment. The cytotoxic effect of cynaropicrin was due to inducing apoptosis and cell cycle arrest at G1/S phase, according to flow-cytometric, DNA fragmentation and morphological analyses using U937 cells. Evidence that combination treatment with l-cysteine and N-acetyl-l-cysteine, reactive oxygen species scavengers, or rottlerin (1-[6-[(3-acetyl-2,4,6-trihydroxy-5-methylphenyl)methyl]-5,7-dihydroxy-2, 2-dimethyl-2H-1-benzopyran-8-yl]-3-phenyl-2-propen-1-one), a specific protein kinase (PK) Cdelta inhibitor, abolished cynaropicrin-mediated cytotoxicity and morphological change, and that cynaropicrin-induced proteolytic cleavage of PKCdelta suggests that reactive oxygen species and PKCdelta may play an important role in mediating pro-apoptotic activity by cynaropicrin. Taken together, these results indicate that cynaropicrin may be a potential anticancer agent against some leukocyte cancer cells such as lymphoma or leukemia, through pro-apoptotic activity.

  15. Apoptosis of DU145 human prostate cancer cells induced by dehydrocostus lactone isolated from the root of Saussurea lappa.

    PubMed

    Kim, Eun Ji; Lim, Soon Sung; Park, So Young; Shin, Hyun-Kyung; Kim, Jong-Sang; Park, Jung Han Yoon

    2008-12-01

    Saussurea lappa (SL) is a plant regularly utilized in traditional herbal medicine, and in vitro cell culture studies have demonstrated that SL has anti-ulcer, anti-inflammatory, and anti-tumor properties. In order to explore the possibility that SL exerts chemopreventive effects in androgen-independent prostate cancer, we attempted to determine whether the hexane extract of SL (HESL) induces apoptosis of DU145 cells, as well as the mechanisms underlying this effect. HESL substantially reduced the number of viable cells and induced apoptosis in DU145 cells in a dose-dependent manner. HESL-induced the cleavage of poly (ADP-ribose) polymerase (PARP) and caspases 8, 9, 7, and 3. HESL increased the protein levels of Bax, Bak, Bok, Bik, truncated Bid (t-Bid), and Bmf with a concomitant increase in the permeability of the mitochondrial membrane and in the release of cytochrome c from the mitochondria. The active fraction of HESL was isolated by column chromatography and the structure of the active compound dehydrocostus lactone (DHCL) was identified via (1)H NMR and (13)C NMR. DHCL promoted apoptosis with increased activation of caspases 8, 9, 7, 3, enhanced PARP cleavage, decreased Bcl-xL expression and increased levels of Bax, Bak, Bok, Bik, Bmf, and t-Bid. We have demonstrated that HESL and its active principle, DHCL, inhibit cell growth and induce apoptosis in DU145 cells.

  16. Bioassay-guided isolation of dehydrocostus lactone from Saussurea lappa: A new targeted cytosolic thioredoxin reductase anticancer agent.

    PubMed

    Yang, Meili; Zhang, Junmin; Li, Ya; Han, Xiao; Gao, Kun; Fang, Jianguo

    2016-10-01

    In a screen for mammalian thioredoxin reductases inhibitors, an MeOH extract from the roots of Saussurea lappa C.B. Clarke (Compositae) inhibited the activity of cytosolic thioredoxin reductase (TrxR1). Bioassay-guided separation of the extract led to the isolation of a new TrxR1 inhibitor, dehydrocostus lactone (DHC), a guaiane-type sesquiterpene. The content of DHC in the extract was determined to be 0.4%. DHC inhibited human cervical carcinoma HeLa cells with an IC50 of ∼12.00 μM but displayed less cytotoxicity to human immortalized normal liver cells L02. We observed that DHC killed HeLa cells through induction of apoptosis. DHC inhibited the activity of TrxR1 in HeLa cells, which elicited an accumulation of reactive oxygen species (ROS) in cells and a collapse of the intracellular redox equilibrium and eventually induced apoptosis of HeLa cells.

  17. A Method for the Simultaneous Determination of Chlorogenic Acid and Sesquiterpene Lactone Content in Industrial Chicory Root Foodstuffs

    PubMed Central

    Hance, Philippe; Fertin, Anne; Voedts, Najia; Duhal, Nathalie; Goossens, Jean-François; Hilbert, Jean-Louis

    2014-01-01

    A method for the simultaneous determination of free chlorogenic acids (CGA) and sesquiterpene lactones (STL) in chicory root and its dried (flour) and roasted (grain) forms is described. The method uses one extraction and one analysis for all chicory root products. Various solvents with low to high polarity, such as methanol, chloroform, or n-hexane, were tested alone, in combination in different proportions or with acidified or neutral aqueous solvent. The water/chloroform/methanol (30/30/40, v/v/v) mixture generated the best extraction yield, 21% higher than alcohol mixtures. The profiling of CGA and STL content was performed through a conventional HPLC-DAD method using a PFP core shell column in a fast single run. Good retention time and area repeatability (RDD mean % 0.46 and 5.6, resp.) and linearity (R2 ≥ 0.96) were obtained. The STL and chlorogenic acids levels determined were 254.7 and 100.2 μg/g of dry matter in the root, 792.5 and 1,547 μg/g in flour, and 160.4 and 822.5 μg/g in the roasted grains, respectively. With an average recovery of 106% and precision of 90%, this method is rapid, reproducible, and straightforward way to quantify the chlorogenic acids and STL in chicory raw material and end products. PMID:25548785

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

    PubMed

    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.

  19. Oxidative ring cleavage of low chlorinated biphenyl derivatives by fungi leads to the formation of chlorinated lactone derivatives.

    PubMed

    Sietmann, Rabea; Gesell, Manuela; Hammer, Elke; Schauer, Frieder

    2006-07-01

    The yeast Trichosporon mucoides and the filamentous fungus Paecilomyces lilacinus as biphenyl oxidizing organisms are able to oxidize chlorinated biphenyl derivatives. Initial oxidation of derivatives chlorinated at C4 position started at the non-halogenated ring and went on up to ring cleavage. The products formed were mono- and dihydroxylated 4-chlorobiphenyls, muconic acid derivatives 2-hydroxy-4-(4-chlorophenyl)-muconic acid and 2-hydroxy-5-(4-chlorophenyl)-muconic acid as well as the corresponding lactones 4-(4-chlorophenyl)-2-pyrone-6-carboxylic acid and 3-(4-chlorophenyl)-2-pyrone-6-carboxylic acid. Altogether T. mucoides formed 12 products and P. lilacinus accumulated five products. Whereas the rate of the first oxidation step at 4-chlorobiphenyl seems to be diminished by the decreased bioavailability of the compound, no considerable differences were observed between the degradation of 4-chloro-4'-hydroxybiphenyl and 4-hydroxybiphenyl. Twofold chlorinated biphenyl derivatives did not serve as substrates for oxidation by either organism with the exception of 2,2'-dichlorobiphenyl, transformed by the yeast Trichosporon mucoides to two monohydroxylated derivatives. The results show, that soil fungi may contribute to the aerobic degradation of low chlorinated biphenyls accumulating from anaerobic dehalogenation of PCB by bacteria.

  20. Anti-Inflammatory and Cytostatic Activities of a Parthenolide-Like Sesquiterpene Lactone from Cota palaestina subsp. syriaca

    PubMed Central

    Talhouk, Rabih S.; Nasr, Bilal; Fares, Mohamed-Bilal; Ajeeb, Bushra; Nahhas, Rana; Al Aaraj, Lamis; Ghaddar, Tarek H.; Saliba, Najat A.

    2015-01-01

    A sesquiterpene lactone 1-β,10-Epoxy-6-hydroxy-1,10H-inunolide (K100) was isolated through “bioassay-guided fractionation” from Cota palaestina subsp. syriaca, an Eastern Mediterranean endemic plant. K100 inhibited endotoxin- (ET-) induced proinflammatory markers: IL-6, MMP-9, and NO in normal mouse mammary SCp2 Cells. Molecular docking in silico suggested that K100, having highly analogous structure as parthenolide (PTL), an anticancer compound, could bind PTL target proteins at similar positions and with comparable binding affinities. Both compounds, K100 and PTL, inhibited the proliferation and prolonged the S-phase of the cell cycle of breast adenocarcinoma MDA-MB-231 cells grown in 2D cultures. Noncytotoxic concentrations of K100 and PTL decreased the proliferation rate of MDA-MB-231 and shifted their morphology from stellate to spherical colonies in 3D cultures. This was accompanied with a significant increase in the amount of small colonies and a decrease in the amount of large colonies. Moreover, K100 and PTL decreased cellular motility and invasiveness of MDA-MB-231 cells. In summary, these results suggest that K100 exhibits PTL-analogous anti-inflammatory, cytostatic, and antimetastatic effects. PMID:26089941

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

    PubMed

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

    2017-03-01

    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 development of new antibacterials. Penicillin V acylases (PVAs) belong to the Ntn hydrolase superfamily, together with AHL acylases. PVAs are exploited widely in the pharmaceutical industry, but their role in the natural physiology of their native microbes is not clearly understood. This report details the characterization of AHL degradation activity by homotetrameric PVAs from two gram-negative plant pathogenic bacteria, Pectobacterium atrosepticum (PaPVA) and Agrobacterium tumefaciens (AtPVA). Both the PVAs exhibited substrate specificity for degrading long-chain AHLs. Exogenous addition of these enzymes into Pseudomonas aeruginosa greatly diminished the production of elastase and pyocyanin and biofilm formation and increased the survival rate in an insect model of acute infection. Subtle structural differences in the PVA active site that regulate specificity for acyl chain length have been characterized, which could reflect the evolution of AHL-degrading acylases in relation to the environment of the bacteria that produce them and also provide strategies for enzyme engineering. The potential for using these enzymes as therapeutic agents in clinical applications and a few ideas about their possible significance in microbial physiology have also been discussed.

  2. Stereoselective α-fluoroamide and α-fluoro-γ-lactone synthesis by an asymmetric zwitterionic aza-Claisen rearrangement

    PubMed Central

    Tenza, Kenny; Northen, Julian S; O'Hagan, David; Slawin, Alexandra MZ

    2005-01-01

    Background Asymmetric introduction of fluorine α-to a carbonyl has become popular recently, largely because the direct fluorination of enolates by asymmetric electrophilic fluorinating reagents has improved, and as a result such compounds are becoming attractive synthons. We have sought an alternative but straightforward asymmetric method to this class of compounds, utilising the zwitterionic aza-Claisen rearrangement by reacting α-fluoroacid chlorides and homochiral N-allylpyrrolidines as starting materials. Results Treatment of N-allylmorpholine with 2-fluoropropionyl chloride under Yb(OTf)3 catalysis generated the zwitterionic aza-Claisen rearrangement product in good yield and demonstrated the chemical feasibility of the approach. For the asymmetric reaction, N-allyl-(S)-2-(methoxymethyl)pyrrolidine was treated with either 2-fluoropropionyl chloride or 2-fluorophenylacetic acid chloride under similar conditions and resulted in N-(α-fluoro-γ-vinylamide)pyrrolidine products as homochiral materials in 99% de. These products were readily converted to their corresponding α-fluoro-γ-lactones by iodolactonisation and in good diastereoselectivity. Conclusion Molecules which have fluorine at a stereogeneic centre are finding increasing utility in pharmaceutical, fine chemicals and materials research. The zwitterionic aza-Claisen rearrangement proved to be an effective and competitive complement to asymmetric electrophilic fluorination strategies and provides access to versatile synthetic intermediates with fluorine at the stereogenic centre. PMID:16542024

  3. N-acylhomoserine lactone-regulation of genes mediating motility and pathogenicity in Pseudomonas syringae pathovar tabaci 11528.

    PubMed

    Cheng, Feifei; Ma, Anzhou; Luo, Jinxue; Zhuang, Xuliang; Zhuang, Guoqiang

    2017-01-29

    Pseudomonas syringae pathovar tabaci 11528 (P. syringae 11528) is a phytopathogen that causes wild-fire disease in soybean and tobacco plants. It utilizes a cell density-dependent regulation system known as quorum sensing (QS). In its QS system, the psyI is responsible for the biosynthesis of N-acylhomoserine lactones (AHLs). By comparing the transcripts from P. syringae 11528 wild-type strain with those of the ΔpsyI mutant using RNA sequencing (RNA-seq) technology, 1118 AHL-regulated genes were identified in the transition from exponential to stationary growth phase. Numerous AHL-regulated genes involved in pathogenicity were negatively controlled, including genes linked to flagella, chemotaxis, pilus, extracellular polysaccharides, secretion systems, and two-component system. Moreover, gene ontology and pathway enrichment analysis revealed that the most pronounced regulation was associated with bacterial motility. Finally, phenotypic assays showed that QS-regulated traits were involved in epiphytic growth of pathogens and disease development in plants. These findings imply that the AHL-mediated QS system in P. syringae 11528 plays significant roles in distinct stages of interactions between plants and pathogens, including early plant colonization and late plant infection.

  4. Elevated Temperature Enhances Short to Medium Chain Acyl Homoserine Lactone Production by Black Band Disease Associated Vibrios.

    PubMed

    Bhedi, Chinmayee D; Prevatte, Carson W; Lookadoo, Maggie S; Waikel, Patricia A; Gillevet, Patrick M; Sikaroodi, Masoumeh; Campagna, Shawn R; Richardson, Laurie L

    2017-01-29

    Black band disease (BBD) of corals is a horizontally migrating, pathogenic, polymicrobial mat community which is active above a temperature threshold of 27.5°C on the reef. Bacterial isolates from BBD, the surface mucopolysaccharide layer (SML) of healthy corals, and SML of healthy areas of BBD infected corals were tested for production of short to medium chain acyl homoserine lactones (AHLs) using the Chromobacterium violaceum CV026 reporter strain. Of 110 bacterial isolates tested, 19 produced AHLs and 15 of these were from BBD. Eight AHLs were identified using LC-MS/MS, with 3OHC4 the most commonly produced, followed by C6. AHL-producing isolates exposed to three temperatures (24°, 27°, 30°C) revealed that production of three AHLs (3OHC4, 3OHC5, and 3OHC6) significantly increased at 30°C when compared to 24°C. 16S rRNA gene sequencing revealed that all of the AHL producing BBD isolates were vibrios. Metagenomic data of BBD communities showed the presence of AHL (and autoinducer-2) genes, many of which are known to be associated with vibrios. These findings suggest that quorum sensing may be involved in BBD pathobiology and community structure due to enhanced production of quorum sensing signal molecules (AHLs) above the temperature threshold of this globally distributed coral disease.

  5. Exogenous N-acyl-homoserine lactones enhance the expression of flagella of Pseudomonas syringae and activate defence responses in plants.

    PubMed

    Cheng, Feifei; Ma, Anzhou; Zhuang, Guoqiang; Fray, Rupert G

    2016-10-18

    In order to cope with pathogens, plants have evolved sophisticated mechanisms to sense pathogenic attacks and to induce defence responses. The N-acyl-homoserine lactone (AHL)-mediated quorum sensing in bacteria regulates diverse physiological processes, including those involved in pathogenicity. In this work, we study the interactions between AHL-producing transgenic tobacco plants and Pseudomonas syringae pv. tabaci 11528 (P. syringae 11528). Both a reduced incidence of disease and decrease in the growth of P. syringae 11528 were observed in AHL-producing plants compared with wild-type plants. The present data indicate that plant-produced AHLs enhance disease resistance against this pathogen. Subsequent RNA-sequencing analysis showed that the exogenous addition of AHLs up-regulated the expression of P. syringae 11528 genes for flagella production. Expression levels of plant defence genes in AHL-producing and wild-type plants were determined by quantitative real-time polymerase chain reaction. These data showed that plant-produced AHLs activated a wide spectrum of defence responses in plants following inoculation, including the oxidative burst, hypersensitive response, cell wall strengthening, and the production of certain metabolites. These results demonstrate that exogenous AHLs alter the gene expression patterns of pathogens, and plant-produced AHLs either directly or indirectly enhance plant local immunity during the early stage of plant infection.

  6. Synthesis and Biological Evaluation of Triazole-Containing N-Acyl Homoserine Lactones as Quorum Sensing Modulators

    PubMed Central

    Stacy, Danielle M.; Le Quement, Sebastian T.; Hansen, Casper L.; Clausen, Janie W.; Tolker-Nielsen, Tim; Brummond, Jacob W.; Givskov, Michael; Nielsen, Thomas E.; Blackwell, Helen E.

    2013-01-01

    Many bacterial species are capable of assessing their local population densities through a cell-cell signaling mechanism termed quorum sensing (QS). This intercellular communication process is mediated by small molecule or peptide ligands and their cognate protein receptors. Numerous pathogens use QS to initiate virulence once they achieve a threshold cell number on a host. Consequently, approaches to intercept QS have attracted considerable attention as potential anti-infective therapies. Our interest in the development of small molecule tools to modulate QS pathways motivated us to evaluate triazole-containing analogs of natural N-acyl L-homoserine lactone (AHL) signals as non-native QS agonists and antagonists in Gram-negative bacteria. We synthesized 72 triazole derivatives of five broad structure types in high yields and purities using efficient Cu(I)-catalyzed azide-alkyne couplings. These compounds were evaluated for their ability to activate or inhibit two QS receptors from two prevalent pathogens – LasR from Pseudomonas aeruginosa and AbaR from Acinetobacter baumannii – using bacterial reporter strains. Several triazole derivatives were identified that were capable of strongly modulating the activity of LasR and AbaR. These compounds represent a new and synthetically accessible class of AHL analogs, and could find utility as chemical tools to study QS and its role in bacterial virulence. PMID:23258305

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

    PubMed

    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.

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

    PubMed

    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.

  9. Determination of D-saccharic acid-1,4-lactone from brewed kombucha broth by high-performance capillary electrophoresis.

    PubMed

    Wang, Kan; Gan, Xuhua; Tang, Xinyun; Wang, Shuo; Tan, Huarong

    2010-02-01

    Kombucha is a health tonic. D-saccharic acid-1,4-lactone (DSL), a component of kombucha, inhibits the activity of glucuronidase, an enzyme indirectly related with cancers. To date, there is no efficient method to determine the content of DSL in kombucha samples. In this paper, we report a rapid and simple method for the separation and determination of DSL in kombucha samples, using the high-performance capillary electrophoresis (HPCE) method with diode array detection (DAD). With optimized conditions, DSL can be separated in a 50 cm length capillary at a separation voltage of 20 kV in 40 mmol/L borax buffer (pH 6.5) containing 30 mmol/L SDS and 15% methanol (v/v). Quantitative evaluation of DSL was determined by ultraviolet absorption at lambda=190 nm. The relationship between the peak areas and the DSL concentrations, in a specified working range with linear response, was determined by first-order polynomial regression over the range 50-1500 microg/mL with a detection limit of 17.5 microg/mL. Our method demonstrated excellent reproducibility and accuracy with relative standard deviations (RSD) of less than 5% DSL content (n=5). This is the first report to determine DSL by HPCE. We have successfully applied this method to determine DSL in kombucha samples in various fermented conditions.

  10. A New N-Acyl Homoserine Lactone Synthase in an Uncultured Symbiont of the Red Sea Sponge Theonella swinhoei

    PubMed Central

    Britstein, Maya; Devescovi, Giulia; Handley, Kim M.; Malik, Assaf; Haber, Markus; Saurav, Kumar; Teta, Roberta; Costantino, Valeria; Burgsdorf, Ilia; Gilbert, Jack A.; Sher, Noa; Venturi, Vittorio

    2015-01-01

    Sponges harbor a remarkable diversity of microbial symbionts in which signal molecules can accumulate and enable cell-cell communication, such as quorum sensing (QS). Bacteria capable of QS were isolated from marine sponges; however, an extremely small fraction of the sponge microbiome is amenable to cultivation. We took advantage of community genome assembly and binning to investigate the uncultured majority of sponge symbionts. We identified a complete N-acyl-homoserine lactone (AHL)-QS system (designated TswIR) and seven partial luxI homologues in the microbiome of Theonella swinhoei. The TswIR system was novel and shown to be associated with an alphaproteobacterium of the order Rhodobacterales, here termed Rhodobacterales bacterium TS309. The tswI gene, when expressed in Escherichia coli, produced three AHLs, two of which were also identified in a T. swinhoei sponge extract. The taxonomic affiliation of the 16S rRNA of Rhodobacterales bacterium TS309 to a sponge-coral specific clade, its enrichment in sponge versus seawater and marine sediment samples, and the presence of sponge-specific features, such as ankyrin-like domains and tetratricopeptide repeats, indicate a likely symbiotic nature of this bacterium. PMID:26655754

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

    PubMed Central

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

    2016-01-01

    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. PMID:27760990

  12. Diversity and N-acyl-homoserine lactone production by Gammaproteobacteria associated with Avicennia marina rhizosphere of South Indian mangroves.

    PubMed

    Viswanath, Ganga; Jegan, Sekar; Baskaran, Viswanathan; Kathiravan, Raju; Prabavathy, Vaiyapuri Ramalingam

    2015-07-01

    The diversity of N-acyl-homoserine lactone (AHL)-producing rhizosphere bacterial community associated with Avicennia marina in the mangrove ecosystems of South India was investigated. Approximately 800 rhizobacteria were isolated from A. marina, and they were screened for the production of AHL using two biosensors, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens NTL4 (pZLR4). Among the total isolates screened, 7% of the rhizobacteria showed positive induction for AHL signals. The BOX-PCR profile of 56 positive isolates represented 11 distinct genotypic groups. Phylogenetic analyses of the 16S rRNA sequences of 16 representatives showed that the isolates belonged to the class Gammaproteobacteria, which represented six different genera: Pseudomonas, Aeromonas, Vibrio, Photobacterium, Serratia and Halomonas. The study also identified three AHL-producing species, namely, Photobacterium halotolerans MSSRF QS48, Vibrio xiamenensis MSSRF QS47 and Pseudomonas sp. MSSRF QS1 that had not been reported previously. AHL profiling by TLC detected short chains C4, C6 and C8-HSL, and long chains C10 and C12-HSL with both unsubstituted and substituted side chains among the 16 representative AHL positives. This is the first report concerning the diversity of AHL-producing Gammaproteobacteria from mangrove ecosystems exhibiting diverse AHL profiles.

  13. Effects of High-Pressure, Microbial Transglutaminase and Glucono-δ-Lactone on the Aggregation Properties of Skim Milk

    PubMed Central

    Lee, Sang Yoon; Choi, Mi-Jung; Cho, Hyung-Yong

    2016-01-01

    The object in this study is to investigate the effects of high pressure and freezing processes on the curdling of skim milk depending on the presence of transglutaminase (TGase) and glucono-δ-lactone (GdL). Skim milk was treated with atmospheric freezing (AF), high pressure (HP), pressure-shift freezing (PSF) and high pressure sub-zero temperature (HPST) processing conditions. After freezing and pressure processing, these processed milk samples were treated with curdling agents, such as TGase and GdL. Pressurized samples (HP, PSF and HPST) had lower lightness than that of the control. In particular, PSF had the lowest lightness (p<0.05). Likewise, the PSF proteins were the most insoluble regardless of whether they were activated by TGase and GdL, indicating the highest rate of protein aggregation (p<0.05). Furthermore, the TGase/GdL reaction resulted in thick bands corresponding to masses larger than 69 kDa, indicating curdling. Casein bands were the weakest in PSF-treated milk, revealing that casein was prone to protein aggregation. PSF also had the highest G' value among all treatments after activation by TGase, implying that PSF formed the hardest curd. However, adding GdL decreased the G' values of the samples except HPST-treated samples. Synthetically, the PSF process was advantageous for curdling of skim milk. PMID:27433104

  14. Inhibitory role of acyl homoserine lactones in hemolytic activity and viability of Streptococcus pyogenes M6 S165

    PubMed Central

    Saroj, Sunil D.; Holmer, Linda; Berengueras, Júlia M.; Jonsson, Ann-Beth

    2017-01-01

    Streptococcus pyogenes an adapted human pathogen asymptomatically colonizes the nasopharynx, among other polymicrobial communities. However, information on the events leading to the colonization and expression of virulence markers subject to interspecies and host-bacteria interactions are limited. The interference of acyl homoserine lactones (AHLs) with the hemolytic activity and viability of S. pyogenes M6 S165 was examined. AHLs, with fatty acid side chains ≥12 carbon atoms, inhibited hemolytic activity by downregulating the expression of the sag operon involved in the production of streptolysin S. Inhibitory AHLs upregulated the expression of transcriptional regulator LuxR. Electrophoretic mobility shift assays revealed the interaction of LuxR with the region upstream of sagA. AHL-mediated bactericidal activity observed at higher concentrations (mM range) was an energy-dependent process, constrained by the requirement of glucose and iron. Ferrichrome transporter FtsABCD facilitated transport of AHLs across the streptococcal membrane. The study demonstrates a previously unreported role for AHLs in S. pyogenes virulence. PMID:28303956

  15. A method for the simultaneous determination of chlorogenic acid and sesquiterpene lactone content in industrial chicory root foodstuffs.

    PubMed

    Willeman, Honorine; Hance, Philippe; Fertin, Anne; Voedts, Najia; Duhal, Nathalie; Goossens, Jean-François; Hilbert, Jean-Louis

    2014-01-01

    A method for the simultaneous determination of free chlorogenic acids (CGA) and sesquiterpene lactones (STL) in chicory root and its dried (flour) and roasted (grain) forms is described. The method uses one extraction and one analysis for all chicory root products. Various solvents with low to high polarity, such as methanol, chloroform, or n-hexane, were tested alone, in combination in different proportions or with acidified or neutral aqueous solvent. The water/chloroform/methanol (30/30/40, v/v/v) mixture generated the best extraction yield, 21% higher than alcohol mixtures. The profiling of CGA and STL content was performed through a conventional HPLC-DAD method using a PFP core shell column in a fast single run. Good retention time and area repeatability (RDD mean % 0.46 and 5.6, resp.) and linearity (R2≥0.96) were obtained. The STL and chlorogenic acids levels determined were 254.7 and 100.2 μg/g of dry matter in the root, 792.5 and 1,547 μg/g in flour, and 160.4 and 822.5 μg/g in the roasted grains, respectively. With an average recovery of 106% and precision of 90%, this method is rapid, reproducible, and straightforward way to quantify the chlorogenic acids and STL in chicory raw material and end products.

  16. Anthelmintic activity of chicory (Cichorium intybus): in vitro effects on swine nematodes and relationship to sesquiterpene lactone composition.

    PubMed

    Williams, Andrew R; Peña-Espinoza, Miguel A; Boas, Ulrik; Simonsen, Henrik T; Enemark, Heidi L; Thamsborg, Stig M

    2016-05-01

    Chicory is a perennial crop that has been investigated as a forage source for outdoor-reared ruminants and pigs, and has been reported to have anthelmintic properties. Here, we investigated in vitro anthelmintic effects of forage chicory-extracts against the highly prevalent swine parasites Ascaris suum and Oesophagostomum dentatum. Methanol extracts were prepared and purified from two different cultivars of chicory (Spadona and Puna II). Marked differences were observed between the anthelmintic activity of extracts from the two cultivars. Spadona extracts had potent activity against A. suum third (L3) and fourth (L4) - stage larvae, as well as O. dentatum L4 and adults, whereas Puna II extracts had less activity against A. suum and no activity towards O. dentatum L4. Transmission-electron microscopy of A. suum L4 exposed to Spadona extracts revealed only subtle changes, perhaps indicative of a specific anthelmintic effect rather than generalized toxicity. Ultra-high liquid chromatography-mass spectrometry analysis revealed that the purified extracts were rich in sesquiterpene lactones (SL), and that the SL profile differed significantly between cultivars. This is the first report of anthelmintic activity of forage chicory towards swine nematodes. Our results indicate a significant anthelmintic effect, which may possibly be related to SL composition.

  17. Unusual macrocyclic lactone sex pheromone of Parcoblatta lata, a primary food source of the endangered red-cockaded woodpecker.

    PubMed

    Eliyahu, Dorit; Nojima, Satoshi; Santangelo, Richard G; Carpenter, Shannon; Webster, Francis X; Kiemle, David J; Gemeno, Cesar; Leal, Walter S; Schal, Coby

    2012-02-21

    Wood cockroaches in the genus Parcoblatta, comprising 12 species endemic to North America, are highly abundant in southeastern pine forests and represent an important prey of the endangered red-cockaded woodpecker, Picoides borealis. The broad wood cockroach, Parcoblatta lata, is among the largest and most abundant of the wood cockroaches, constituting >50% of the biomass of the woodpecker's diet. Because reproduction in red-cockaded woodpeckers is affected dramatically by seasonal and spatial changes in arthropod availability, monitoring P. lata populations could serve as a useful index of habitat suitability for woodpecker conservation and forest management efforts. Female P. lata emit a volatile, long-distance sex pheromone, which, once identified and synthesized, could be deployed for monitoring cockroach populations. We describe here the identification, synthesis, and confirmation of the chemical structure of this pheromone as (4Z,11Z)-oxacyclotrideca-4,11-dien-2-one [= (3Z,10Z)-dodecadienolide; herein referred to as "parcoblattalactone"]. This macrocyclic lactone is a previously unidentified natural product and a previously unknown pheromonal structure for cockroaches, highlighting the great chemical diversity that characterizes olfactory communication in cockroaches: Each long-range sex pheromone identified to date from different genera belongs to a different chemical class. Parcoblattalactone was biologically active in electrophysiological assays and attracted not only P. lata but also several other Parcoblatta species in pine forests, underscoring its utility in monitoring several endemic wood cockroach species in red-cockaded woodpecker habitats.

  18. Alteration of gut bacteria and metabolomes after glucaro-1,4-lactone treatment contributes to the prevention of hypercholesterolemia.

    PubMed

    Xie, Baogang; Liu, Aihong; Zhan, Xuejun; Ye, Xinming; Wei, Jing

    2014-07-30

    D-Glucaro-1,4-lactone (1,4-GL) has been shown to have a hypocholesterolemic effect in rats and human subjects. However, little information is known concerning the alteration of metabolome associated with the effect. Here, we show that 1,4-GL delays the development of hypercholesterolemia with the coadministration of a high-fat, high-cholesterol diet (HFHC) in rats. Metabonomic results based on proton nuclear magnetic resonance indicate that urinary trimethylamine N-oxide, trimethylamine, lactate, acetate, formate, and creatinine are significantly altered after 1,4-GL and HFHC treatments. Colonic flora test results reveal that the quantity of Bifidobacterium and Lactobacillus in the intestines respectively increase by about 1.7- and 4.2-fold in rats treated with 1,4-GL compared with those in the control group. Rats that were coadministered with HFHC and 1,4-GL exhibit normal levels of lactate and acetate in serum and display urinary excretions of lactate and acetate that are 2 to 3 times higher compared with those treated with HFHC alone. The results imply that the increased probiotic quantities and urinary excretion of breakdown products of fat/cholesterol after 1,4-GL treatment contribute to the prevention of hypercholesterolemia. Our study offers insights into the model of action for 1,4-GL in preventing hypercholesterolemia.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. 4-Hydroxy-7-oxo-5-heptenoic Acid (HOHA) Lactone is a Biologically Active Precursor for the Generation of 2-(ω-Carboxyethyl)pyrrole (CEP) Derivatives of Proteins and Ethanolamine Phospholipids

    PubMed Central

    Wang, Hua; Linetsky, Mikhail; Guo, Junhong; Choi, Jaewoo; Hong, Li; Chamberlain, Amanda S.; Howell, Scott J.; Howes, Andrew M.; Salomon, Robert G.

    2015-01-01

    2-(ω-Carboxyethyl)pyrrole (CEP) derivatives of proteins were previously shown to have significant pathological and physiological relevance to age-related macular degeneration, cancer and wound healing. Previously, we showed that CEPs are generated in the reaction of ε-amino groups of protein lysyl residues with 1-palmityl-2-(4-hydroxy-7-oxo-5-heptenoyl)-sn-glycero-3-phosphatidylcholine (HOHA-PC), a lipid oxidation product uniquely generated by oxidative truncation of docosahexanenate-containing phosphatidylcholine. More recently, we found that HOHA-PC rapidly releases HOHA-lactone and 2-lyso-PC (t1/2 = 30 min at 37 °C) by non-enzymatic transesterification/deacylation. Now we report that HOHA-lactone reacts with Ac-Gly-Lys-OMe or human serum albumin to form CEP derivatives in vitro. Incubation of human red blood cell ghosts with HOHA-lactone generates CEP derivatives of membrane proteins and ethanolamine phospholipids. Quantitative analysis of the products generated in the reaction HOHA-PC with Ac-Gly-Lys-OMe showed that HOHA-PC mainly forms CEP-dipeptide that is not esterified to 2-lysophosphatidycholine. Thus, the HOHA-lactone pathway predominates over the direct reaction of HOHA-PC to produce the CEP-PC-dipeptide derivative. Myleoperoxidase/H2O2/NO2− promoted in vitro oxidation of either 1-palmityl-2-docosahexaneoyl-sn-glycero-3-phosphatidylcholine (DHA-PC) or docosahexaenoic acid (DHA) generates HOHA-lactone in yields of 0.45% and 0.78%, respectively. Lipid oxidation in human red blood cell ghosts also releases HOHA-lactone. Oxidative injury of ARPE-19 human retinal pigmented epithelial cells by exposure to H2O2 generated CEP derivatives. Treatment of ARPE-19 cells with HOHA-lactone generated CEP-modified proteins. Low (submicromolar), but not high, concentrations of HOHA-lactone promote increased vascular endothelial growth factor (VEGF) secretion by ARPE-19 cells. Therefore, HOHA-lactone not only serves as an intermediate for the generation of CEPs but

  1. The hexane extract of Saussurea lappa and its active principle, dehydrocostus lactone, inhibit prostate cancer cell migration.

    PubMed

    Kim, Eun Ji; Hong, Ji Eun; Lim, Soon Sung; Kwon, Gyoo Taik; Kim, Jongdai; Kim, Jong-Sang; Lee, Ki Won; Park, Jung Han Yoon

    2012-01-01

    Saussurea lappa has been used in Chinese traditional medicine for the treatment of abdominal pain, tenesmus, nausea, and cancer; previous studies have shown that S. lappa also induces G(2) growth arrest and apoptosis in gastric cancer cells. In this study, we investigated the effects of hexane extracts of S. lappa (HESLs) on the migration of DU145 and TRAMP-C2 prostate cancer cells. DU145 and TRAMP-C2 cells were cultured in the presence of 0-4 μg/mL HESL with or without 10 ng/mL epidermal growth factor (EGF). HESL inhibited the basal and EGF-induced migration of prostate cancer cells in a dose-dependent manner, whereas HESL did not influence the viability of these cancer cells under the conditions used in this study. Active fractions of HESL were separated via column chromatography, and the structure of the active principle was determined using (1)H and (13)C nuclear magnetic resonance spectroscopy. The active compound, dehydrocostus lactone (DHCL), in fraction 7 dose-dependently inhibited the basal and EGF-induced migration of prostate cancer cells. HESL and DHCL reduced matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 secretion but increased TIMP-2 levels in both the absence and presence of EGF. Our results demonstrate that the inhibition of MMP-9 secretion and the stimulation of TIMP-2 secretion contribute to reduced migration of DU145 cells treated with HESL and DHCL. These results indicate that HESL containing its active principle, DHCL, has potential as an antimetastatic agent for the treatment of prostate cancer.

  2. A new role for penicillin acylases: degradation of acyl homoserine lactone quorum sensing signals by Kluyvera citrophila penicillin G acylase.

    PubMed

    Mukherji, Ruchira; Varshney, Nishant Kumar; Panigrahi, Priyabrata; Suresh, C G; Prabhune, Asmita

    2014-03-05

    Use of penicillin acylases for the production of semi-synthetic penicillins is well-known. Escherichia coli penicillin G acylase (EcPGA) has been extensively used for this purpose; however, Kluyvera citrophila penicillin G acylase (KcPGA) is assumed to be a better substitute, owing to its increased resilience to extreme pH conditions and ease of immobilization. In the present article we report a new dimension for the amidase activity of KcPGA by demonstrating its ability to cleave bacterial quorum sensing signal molecules, acyl homoserine lactones (AHL) with acyl chain length of 6-8 with or without oxo-substitution at third carbon position. Initial evidence of AHL degrading capability of KcPGA was obtained using CV026 based bioassay method. Kinetic studies performed at pH 8.0 and 50 °C revealed 3-oxo-C6 HSL to be the best substrate for the enzyme with V(max) and K(m) values of 21.37+0.85 mM/h/mg of protein and 0.1+0.01 mM, respectively. C6 HSL was found to be the second best substrate with V(max) and K(m) value of 10.06+0.27 mM/h/mg of protein and 0.28+0.02 mM, respectively. Molecular modeling and docking studies performed on the active site of the enzyme support these findings by showing the fitting of AHLs perfectly within the hydrophobic pocket of the enzyme active site.

  3. Quorum sensing of bacteria and trans-kingdom interactions of N-acyl homoserine lactones with eukaryotes.

    PubMed

    Hartmann, Anton; Schikora, Adam

    2012-06-01

    Many environmental and interactive important traits of bacteria, such as antibiotic, siderophore or exoenzyme (like cellulose, pectinase) production, virulence factors of pathogens, as well as symbiotic interactions, are regulated in a population density-dependent manner by using small signaling molecules. This phenomenon, called quorum sensing (QS), is widespread among bacteria. Many different bacterial species are communicating or "speaking" through diffusible small molecules. The production often is sophisticatedly regulated via an autoinducing mechanism. A good example is the production of N-acyl homoserine lactones (AHL), which occur in many variations of molecular structure in a wide variety of Gram-negative bacteria. In Gram-positive bacteria, other compounds, such as peptides, regulate cellular activity and behavior by sensing the cell density. The degradation of the signaling molecule--called quorum quenching--is probably another important integral part in the complex quorum sensing circuit. Most interestingly, bacterial quorum sensing molecules also are recognized by eukaryotes that are colonized by QS-active bacteria. In this case, the cross-kingdom interaction can lead to specific adjustment and physiological adaptations in the colonized eukaryote. The responses are manifold, such as modifications of the defense system, modulation of the immune response, or changes in the hormonal status and growth responses. Thus, the interaction with the quorum sensing signaling molecules of bacteria can profoundly change the physiology of higher organisms too. Higher organisms are obligatorily associated with microbial communities, and these truly multi-organismic consortia, which are also called holobionts, can actually be steered via multiple interlinked signaling substances that originate not only from the host but also from the associated bacteria.

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

    PubMed

    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.

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

    PubMed

    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.

  6. Arthrobacter strain VAI-A utilizes acyl-homoserine lactone inactivation products and stimulates quorum signal biodegradation by Variovorax paradoxus.

    PubMed

    Flagan, Suvi; Ching, Weng-Ki; Leadbetter, Jared R

    2003-02-01

    Many Proteobacteria produce acyl-homoserine lactones (acyl-HSLs) and employ them as dedicated cell-to-cell signals in a process known as quorum sensing. Previously, Variovorax paradoxus VAI-C was shown to utilize diverse acyl-HSLs as sole sources of energy and nitrogen. We describe here the properties of a second isolate, Arthrobacter strain VAI-A, obtained from the same enrichment culture that yielded V. paradoxus VAI-C. Although strain VAI-A grew rapidly and exponentially on a number of substrates, it grew only slowly and aberrantly (i.e., linearly) in media amended with oxohexanoyl-HSL as the sole energy source. Increasing the culture pH markedly improved the growth rate in media containing this substrate but did not abolish the aberrant kinetics. The observed growth was remarkably similar to the known kinetics of the pH-influenced half-life of acyl-HSLs, which decay chemically to yield the corresponding acyl-homoserines. Strain VAI-A grew rapidly and exponentially when provided with an acyl-homoserine as the sole energy or nitrogen source. The isolate was also able to utilize HSL as a sole source of nitrogen but not as energy for growth. V. paradoxus, known to release HSL as a product of quorum signal degradation, was examined for the ability to support the growth of Arthrobacter strain VAI-A in defined cocultures. It did. Moreover, the acyl-HSL-dependent growth rate and yield of the coculture were dramatically superior to those of the monocultures. This suggested that the original coenrichment of these two organisms from the same soil sample was not coincidental and that consortia may play a role in quorum signal turnover and mineralization. The fact that Arthrobacter strain VAI-A utilizes the two known nitrogenous degradation products of acyl-HSLs, acyl-homoserine and HSL, begins to explain why none of the three compounds are known to accumulate in the environment.

  7. Pseudomonas aeruginosa Homoserine Lactone Activates Store-operated cAMP and Cystic Fibrosis Transmembrane Regulator-dependent Cl− Secretion by Human Airway Epithelia*

    PubMed Central

    Schwarzer, Christian; Wong, Steven; Shi, James; Matthes, Elizabeth; Illek, Beate; Ianowski, Juan P.; Arant, Ryan J.; Isacoff, Ehud; Vais, Horia; Foskett, J. Kevin; Maiellaro, Isabella; Hofer, Aldebaran M.; Machen, Terry E.

    2010-01-01

    The ubiquitous bacterium Pseudomonas aeruginosa frequently causes hospital-acquired infections. P. aeruginosa also infects the lungs of cystic fibrosis (CF) patients and secretes N-(3-oxo-dodecanoyl)-S-homoserine lactone (3O-C12) to regulate bacterial gene expression critical for P. aeruginosa persistence. In addition to its effects as a quorum-sensing gene regulator in P. aeruginosa, 3O-C12 elicits cross-kingdom effects on host cell signaling leading to both pro- or anti-inflammatory effects. We find that in addition to these slow effects mediated through changes in gene expression, 3O-C12 also rapidly increases Cl− and fluid secretion in the cystic fibrosis transmembrane regulator (CFTR)-expressing airway epithelia. 3O-C12 does not stimulate Cl− secretion in CF cells, suggesting that lactone activates the CFTR. 3O-C12 also appears to directly activate the inositol trisphosphate receptor and release Ca2+ from the endoplasmic reticulum (ER), lowering [Ca2+] in the ER and thereby activating the Ca2+-sensitive ER signaling protein STIM1. 3O-C12 increases cytosolic [Ca2+] and, strikingly, also cytosolic [cAMP], the known activator of CFTR. Activation of Cl− current by 3O-C12 was inhibited by a cAMP antagonist and increased by a phosphodiesterase inhibitor. Finally, a Ca2+ buffer that lowers [Ca2+] in the ER similar to the effect of 3O-C12 also increased cAMP and ICl. The results suggest that 3O-C12 stimulates CFTR-dependent Cl− and fluid secretion in airway epithelial cells by activating the inositol trisphosphate receptor, thus lowering [Ca2+] in the ER and activating STIM1 and store-operated cAMP production. In CF airways, where CFTR is absent, the adaptive ability to rapidly flush the bacteria away is compromised because the lactone cannot affect Cl− and fluid secretion. PMID:20739289

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

    PubMed

    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.

  9. The interconversion kinetics, equilibrium, and solubilities of the lactone and hydroxyacid forms of the HMG-CoA reductase inhibitor, CI-981.

    PubMed

    Kearney, A S; Crawford, L F; Mehta, S C; Radebaugh, G W

    1993-10-01

    The pH dependence of the interconversion kinetics, equilibrium, and solubilities of the lactone and hydroxyacid forms of the HMG-CoA reductase inhibitor, CI-981 ([R-(R*,R*)]-2-(4-fluorophenyl)- beta,delta-dihydroxy-5-(1-methylethyl)-3-phenyl-4-[(phenylamino)carbonyl ]- 1H-pyrrole-1-hepatonic acid), are important considerations when choosing and developing one of the forms of these compounds. Over a pH range of 2.1 to 6.0 and at 30 degrees C, the apparent solubility of the sodium salt of CI-981 (i.e., the hydroxyacid form) increases about 60-fold, from 20.4 micrograms/mL to 1.23 mg/mL, and the profile yields a pKa for the terminal carboxyl group of 4.46. In contrast, over a pH range of 2.3 to 7.7 and also at 30 degrees C, the apparent solubility of the lactone form of CI-981 varies little, and the mean solubility is 1.34 (+/- 0.53) micrograms/mL. The kinetics of interconversion and the equilibrium between the hydroxyacid and the lactone forms have been studied as a function of pH, buffer concentration, and temperature at a fixed ionic strength (0.5 M) using a stability-indicating HPLC assay. The acid-catalyzed reaction is reversible, whereas the base-catalyzed reaction can be treated as an irreversible reaction. More specifically, at pH < 6, an equilibrium favoring the hydroxyacid form is established, whereas at pH > 6, the equilibrium reaction is no longer detectable and greatly favors the hydroxyacid form.(ABSTRACT TRUNCATED AT 250 WORDS)

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

    PubMed Central

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

    2016-01-01

    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. PMID:27364593

  11. Two drimane lactones, valdiviolide and 11-epivaldiviolide, in the form of a 1:1 cocrystal obtained from Drimys winteri extracts.

    PubMed

    Paz Robles, Cristian; Mercado, Darío; Suarez, Sebastián; Baggio, Ricardo

    2014-12-01

    A cocrystal, C15H22O3·C15H22O3, (I), obtained from Drimys winteri, is composed of two isomeric drimane sesquiterpene lactones, namely valdiviolide, (Ia), and 11-epivaldiviolide, (Ib), neither of which has been reported in the crystal form. Both diastereoisomers present three chiral centres at sites 5, 10 and 11, with an SSR sequence in (Ia) and an SSS sequence in (Ib). O-H···O hydrogen bonds bind molecules into chains running along [120] and the chains are in turn linked by π-π stacking interactions to define planar weakly interacting arrays parallel to (001).

  12. Insights into the Genome Sequences of an N-Acyl Homoserine Lactone Molecule Producing Two Pseudomonas spp. Isolated from the Arctic

    PubMed Central

    Dharmaprakash, Akhilandeswarre; Reghunathan, Dinesh; Sivakumar, Krishnakutty C.; Prasannakumar, Manoj

    2016-01-01

    We report for the first time the draft genome sequence of two psychrotrophic Pseudomonas species, Pseudomonas simiae RGCB 73 and Pseudomonas brenneri RGCB 108, from the Arctic that produce more than one acyl homoserine lactone molecule of varied N-acyl length. The study confirms the presence of a LuxR-LuxI (type) mediated quorum-sensing system in both the Pseudomonas species and enables us to understand the role of quorum sensing in their survival in extremely cold environments. PMID:27491995

  13. An RpoS (sigmaS) homologue regulates acylhomoserine lactone-dependent autoinduction in Ralstonia solanacearum.

    PubMed

    Flavier, A B; Schell, M A; Denny, T P

    1998-05-01

    Many bacteria sense an appropriate growth condition or a critical population density for gene expression by producing acylhomoserine lactones (acyl-HSLs) that act as intercellular autoinduction signals. We recently showed that, in Ralstonia (Pseudomonas) solanacearum, a phytopathogenic bacterium, acyl-HSL production requires soll, which encodes a putative acyl-HSL synthase, and that its expression is positively regulated by the acyl-HSL-responsive SolR transcriptional regulator. This acyl-HSL-dependent autoinduction system is noteworthy because (i) it is regulated by a 'higher level' autoinducer system (responsive to 3-hydroxypalmitic acid methyl ester) via PhcA, a LysR-type transcriptional regulator and (ii) acyl-HSL production requires two additional unlinked loci. As reported here, cloning and sequencing of one of these other loci revealed that it encodes a homologue of RpoS, an alternative sigma factor (sigmaS) that in other bacteria activates gene expression during stationary phase or in response to stress conditions. R. solanacearum RpoS (RpoS(Rso)) was demonstrated to function as a sigma factor because when introduced in trans into an Escherichia coli rpoS mutant it largely restored expression of the RpoS-dependent bolAp1 gene. Mutation of rpoS(Rso) in R. solanacearum reduced survival during starvation and low pH conditions, but did not affect survival during exposure to hydrogen peroxide, high osmolarity or high temperature. This mutant was also altered in its production of several virulence factors and wilted tomato plants several days more slowly than the wild-type parent. Transcription of solR and soll were decreased in an rpoS(Rso) background (thereby reducing acyl-HSL production), but neither mutations in solR, soll or phcA nor addition of acyl-HSLs affected rpoS(Rso) expression. Therefore, in R. solanacearum the acyl-HSL-dependent autoinduction system is controlled both by a second autoinduction system and by the RpoS(Rso) sigma factor.

  14. Bromoenol lactone promotes cell death by a mechanism involving phosphatidate phosphohydrolase-1 rather than calcium-independent phospholipase A2.

    PubMed

    Fuentes, Lucía; Pérez, Rebeca; Nieto, María L; Balsinde, Jesús; Balboa, María A

    2003-11-07

    Originally described as a serine protease inhibitor, bromoenol lactone (BEL) has recently been found to potently inhibit Group VI calcium-independent phospholipase A2 (iPLA2). Thus, BEL is widely used to define biological roles of iPLA2 in cells. However, BEL is also known to inhibit another key enzyme of phospholipid metabolism, namely the magnesium-dependent phosphatidate phosphohydrolase-1 (PAP-1). In this work we report that BEL is able to promote apoptosis in a variety of cell lines, including U937, THP-1, and MonoMac (human phagocyte), RAW264.7 (murine macrophage), Jurkat (human T lymphocyte), and GH3 (human pituitary). In these cells, long term treatment with BEL (up to 24 h) results in increased annexin-V binding to the cell surface and nuclear DNA damage, as detected by staining with both DAPI and propidium iodide. At earlier times (2 h), BEL induces the proteolysis of procaspase-9 and procaspase-3 and increases cleavage of poly(ADP-ribose) polymerase. These changes are preceded by variations in the mitochondrial membrane potential. All these effects of BEL are not mimicked by the iPLA2 inhibitor methylarachidonyl fluorophosphonate or by treating the cells with a specific iPLA2 antisense oligonucleotide. However, propranolol, a PAP-1 inhibitor, is able to reproduce these effects, suggesting that it is the inhibition of PAP-1 and not of iPLA2 that is involved in BEL-induced cell death. In support of this view, BEL-induced apoptosis is accompanied by a very strong inhibition of PAP-1-regulated events, such as incorporation of [3H]choline into phospholipids and de novo incorporation of [3H]arachidonic acid into triacylglycerol. Collectively, these results stress the role of PAP-1 as a key enzyme for cell integrity and survival and in turn caution against the use of BEL in studies involving long incubation times, due to the capacity of this drug to induce apoptosis in a variety of cells.

  15. Increased production of γ-lactones from hydroxy fatty acids by whole Waltomyces lipofer cells induced with oleic acid.

    PubMed

    An, Jung-Ung; Oh, Deok-Kun

    2013-09-01

    Among several fatty acids tested, oleic acid was selected as the most efficient inducer for the production of 4-hydroxydodecanoic acid, a metabolite of β-oxidation, by Waltomyces lipofer. Cells were induced by incubation for 12 h in a medium containing 10 g l(-1) yeast extract, 10 g l(-1) peptone, 5 g l(-1) oleic acid, 1 g l(-1) glucose, and 0.05 % (w/v) Tween 80. The optimal reaction conditions for the production of γ-lactones by induced cells were pH 6.5, 35 °C, 200 rpm, 0.71 M Tris, 60 g l(-1) hydroxy fatty acid, and 20 g l(-1) cells. Non-induced cells produced 38 g l(-1) γ-dodecalactone from 60 g l(-1) 10-hydroxystearic acid after 30 h, with a conversion yield of 63 % (w/w) and a productivity of 1.3 g l(-1) h(-1) under the optimized conditions, whereas induced cells produced 51 g l(-1) γ-dodecalactone from 60 g l(-1) 10-hydroxystearic acid after 30 h, with a conversion yield of 85 % (w/w) and a productivity of 1.7 g l(-1) h(-1). The conversion yield and productivity of induced cells were 22 % and 1.3-fold higher, respectively, than those of non-induced cells. Induced cells also produced 28 g l(-1) γ-decalactone and 12 g l(-1) γ-butyrolactone from 60 g l(-1) 12-hydroxystearic acid and 60 g l(-1) 10-hydroxydecanoic acid, respectively, after 30 h. The concentration, conversion yield, and productivity of γ-dodecalactone and γ-decalactone are the highest reported thus far. This is the first study on the biotechnological production of γ-butyrolactone.

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

    PubMed

    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.

  17. Complete genome sequencing of Pandoraea pnomenusa RB38 and Molecular Characterization of Its N-acyl homoserine lactone synthase gene ppnI

    PubMed Central

    Lim, Yan-Lue; Ee, Robson; How, Kah-Yan; Lee, Siew-Kim; Yong, Delicia; Tee, Kok Keng; Yin, Wai-Fong

    2015-01-01

    In this study, we sequenced the genome of Pandoraea pnomenusa RB38 using Pacific Biosciences RSII (PacBio) Single Molecule Real Time (SMRT) sequencing technology. A pair of cognate luxI/R homologs was identified where the luxI homolog, ppnI, was found adjacent to a luxR homolog, ppnR1. An additional orphan luxR homolog, ppnR2, was also discovered. Multiple sequence alignment and phylogenetic analysis revealed that ppnI is an N-acyl homoserine lactone (AHL) synthase gene that is distinct from those of the nearest phylogenetic neighbor viz. Burkholderia spp. High resolution tandem mass spectrometry (LC-MS/MS) analysis showed that Escherichia coli BL21 harboring ppnI produced a similar AHL profile (N-octanoylhomoserine lactone, C8-HSL) as P. pnomenusa RB38, the wild-type donor strain, confirming that PpnI directed the synthesis of AHL in P. pnomenusa RB38. To our knowledge, this is the first documentation of the luxI/R homologs of the genus Pandoraea. PMID:26336650

  18. Preliminary study on an innovative, simple mast cell-based electrochemical method for detecting foodborne pathogenic bacterial quorum signaling molecules (N-acyl-homoserine-lactones).

    PubMed

    Jiang, Donglei; Feng, Dongdong; Jiang, Hui; Yuan, Limin; Yongqi, Yin; Xu, Xin; Fang, Weiming

    2017-04-15

    This paper reports the a novel and simple mast cell-based electrochemical method for detecting of bacterial quorum signaling molecules, N-acylhomoserine lactones (AHLs), which can be utilized to preliminarily evaluate the toxicity of food-borne pathogenic bacteria. Rat basophilic leukemia (RBL-2H3) mast cells encapsulated in alginate/graphene oxide hydrogel were immobilized on a gold electrode, while mast cells as recognition elements were cultured in a 3D cell culture system. Electrochemical impedance spectroscopy (EIS) was utilized to record the cell impedance signal as-influenced by Pseudomonas aeruginosa quorum-sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC12-HSL). The results indicated that cellular activities such as cell viability, apoptosis, intracellular calcium, and degranulation were markedly influenced by the AHLs. Importantly, the exposure of 3OC12-HSL to mast cells induced a marked decrease in the electrochemical impedance signal in a dose-dependent manner. The detection limit for 3OC12-HSL was 0.034μM with a linear range of 0.1-1μM. These results were confirmed via conventional cell assay and transmission electron microscope (TEM) analysis. Altogether, the proposed method appears to be an innovative and effective approach to the quantitative measurement of Gram-negative bacterial quorum signaling molecules; to this effect, it also may serve as a primary evaluation of the cytotoxicity of food-borne pathogens.

  19. Isolation of a new 15-membered macrocyclic glycolipid lactone, Cuscutic Resinoside a from the seeds of Cuscuta chinensis: a stimulator of breast cancer cell proliferation.

    PubMed

    Umehara, Kaoru; Nemoto, Kiyomitsu; Ohkubo, Tsutomu; Miyase, Toshio; Degawa, Masakuni; Noguchi, Hiroshi

    2004-04-01

    While searching for new estrogenic compounds from the plant kingdom, we investigated an extract of the seeds of Cuscuta chinensis (Convolvulaceae) which showed potency for stimulating MCF-7 cell proliferation. A novel resin glycoside, cuscutic resinoside A ( 6) was isolated along with five known compounds from the extract. The structure was deduced from its spectral data as (11 S)-hydroxyhexadecanoic acid 11- O-alpha- L-(4- O-2 R,3 R-nilylrhamnopyranosyl)-(1-->2)- O-alpha- L-rhamnopyranosyl-(1,2-lactone) forming a unique 15-membered macrocyclic lactone. The compound significantly stimulated not only MCF-7 cell proliferation but also T47D human breast cancer cells at a concentration of 10 microM. Along with cuscutamine ( 1) and kaempferol ( 4), 6 was tested in the transient luciferase reporter assay and was found to have different luciferase inducing activity characteristics from the other compounds. These results suggest that 6 stimulated cancer cell proliferation by a different mechanism from 1 and 4.

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

    PubMed

    Chang, Chien-Yi; Koh, Chong-Lek; Sam, Choon-Kook; Chan, Xin-Yue; Yin, Wai Fong; Chan, Kok Gan

    2012-01-01

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

  1. The Addition of N-Hexanoyl-Homoserine Lactone to Improve the Microbial Flocculant Production of Agrobacterium tumefaciens Strain F2, an Exopolysaccharide Bioflocculant-Producing Bacterium.

    PubMed

    Yang, Jixian; Wu, Dan; Li, Ang; Guo, Haijuan; Chen, Han; Pi, Shanshan; Wei, Wei; Ma, Fang

    2016-07-01

    In this study, N-hexanoyl-homoserine lactone (C6-HSL), a member of the N-acyl-homoserine lactone class of microbial quorum sensing (QS) signaling molecules, was used to improve microbial flocculant production. After exogenous C6-HSL was added, exopolysaccharide concentration of microbial flocculants was improved by 1.6-fold and flocculation rate of microbial flocculants was increased by 10 %. Fermentation conditions with added C6-HSL were further optimized through response surface methodology. The obtained optimal fermentation conditions were as follows: added C6-HSL concentration of 0.45 μM, fermentation temperature of 30.4 °C, and initial fermentation pH of 7.25. Under these optimal fermentation conditions, the resulting exopolysaccharide concentration was improved by 1.75-fold and flocculation rate was increased by 10 % compared with that of the control group. The yield of microbial flocculants was also improved by 1.75-fold. Results demonstrated that the existence of QS system in Agrobacterium tumefaciens strain F2 played the important roles in the microbial flocculant production.

  2. Comparative characterization of total flavonol glycosides and terpene lactones at different ages, from different cultivation sources and genders of Ginkgo biloba leaves.

    PubMed

    Yao, Xin; Shang, Erxin; Zhou, Guisheng; Tang, Yuping; Guo, Sheng; Su, Shulan; Jin, Chun; Qian, Dawei; Qin, Yong; Duan, Jin-Ao

    2012-01-01

    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.

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

    PubMed

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

    2013-09-01

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

  4. 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.

    PubMed

    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.

  5. Unusual Long-Chain N-Acyl Homoserine Lactone Production by and Presence of Quorum Quenching Activity in Bacterial Isolates from Diseased Tilapia Fish

    PubMed Central

    Chang, Chien-Yi; Koh, Chong-Lek; Sam, Choon-Kook; Chan, Xin-Yue; Yin, Wai Fong; Chan, Kok Gan

    2012-01-01

    Growth-dependent cell-cell communication termed quorum sensing is a key regulatory system in bacteria for controlling gene expression including virulence factors. In this study five potential bacterial pathogens including Bacillus sp. W2.2, Klebsiella sp. W4.2, Pseudomonas sp. W3 and W3.1 and Serratia sp. W2.3 were isolated from diseased Tilapia fish in Malaysia, supplied by the leading global fish supplier. Proteolytic activity assays confirmed that with the exception of Klebsiella sp. W4.2, all isolates showed distinct proteolytic activity. Furthermore Bacillus sp. W2.2 and Pseudomonas sp. strains W3 and W3.1 also displayed haemolytic activity. By using high resolution liquid chromatography mass spectrometry, we revealed the presence of unusually long-chain N-(3-oxohexadecanoyl)-homoserine lactone (3-oxo-C16-HSL) from Pseudomonas sp. W3.1 and N-dodecanoyl-homoserine lactone (C12-HSL) from Serratia sp. W2.3, respectively. Interestingly, Pseudomonas sp. W3.1 also produced a wide range of Pseudomonas quinolone signalling (PQS) molecules. Pseudomonas sp. W3 did not show any quorum sensing properties but possessed quorum quenching activity that inactivated AHLs. This study is the first documentation that shows unusual long-chain AHLs production in Serratia sp. and Pseudomonas sp. isolated from diseased fish and the latter also produce a wide range of PQS molecules. PMID:22952864

  6. Uptake, degradation and chiral discrimination of N-acyl-D/L-homoserine lactones by barley (Hordeum vulgare) and yam bean (Pachyrhizus erosus) plants.

    PubMed

    Götz, Christine; Fekete, Agnes; Gebefuegi, Istvan; Forczek, Sándor T; Fuksová, Kvetoslava; Li, Xiaojing; Englmann, Matthias; Gryndler, Milan; Hartmann, Anton; Matucha, Miroslav; Schmitt-Kopplin, Philippe; Schröder, Peter

    2007-11-01

    Bacterial intraspecies and interspecies communication in the rhizosphere is mediated by diffusible signal molecules. Many Gram-negative bacteria use N-acyl-homoserine lactones (AHLs) as autoinducers in the quorum sensing response. While bacterial signalling is well described, the fate of AHLs in contact with plants is much less known. Thus, adsorption, uptake and translocation of N-hexanoyl- (C6-HSL), N-octanoyl- (C8-HSL) and N-decanoyl-homoserine lactone (C10-HSL) were studied in axenic systems with barley (Hordeum vulgare L.) and the legume yam bean (Pachyrhizus erosus (L.) Urban) as model plants using ultra-performance liquid chromatography (UPLC), Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and tritium-labelled AHLs. Decreases in AHL concentration due to abiotic adsorption or degradation were tolerable under the experimental conditions. The presence of plants enhanced AHL decline in media depending on the compounds' lipophilicity, whereby the legume caused stronger AHL decrease than barley. All tested AHLs were traceable in root extracts of both plants. While all AHLs except C10-HSL were detectable in barley shoots, only C6-HSL was found in shoots of yam bean. Furthermore, tritium-labelled AHLs were used to determine short-term uptake kinetics. Chiral separation by GC-MS revealed that both plants discriminated D-AHL stereoisomers to different extents. These results indicate substantial differences in uptake and degradation of different AHLs in the plants tested.

  7. Mutational analysis of the quorum-sensing receptor LasR reveals interactions that govern activation and inhibition by non-lactone ligands

    PubMed Central

    Gerdt, Joseph P.; McInnis, Christine E.; Schell, Trevor L.; Rossi, Francis M.; Blackwell, Helen E.

    2014-01-01

    SUMMARY Gram-negative bacteria use N-acyl L-homoserine lactone (AHL) quorum sensing (QS) signals to regulate the expression of myriad phenotypes. Non-native AHL analogs can strongly attenuate QS receptor activity and thereby QS signaling; however, we currently lack a molecular understanding of the mechanisms by which most of these compounds elicit their agonistic or antagonistic profiles. In this study, we investigated the origins of striking activity profile switches (i.e., receptor activator to inhibitor, and vice versa) observed upon alteration of the lactone head group in certain AHL analogs. Reporter gene assays of mutant versions of the Pseudomonas aeruginosa QS receptor LasR revealed that interactions between the ligands and Trp60, Tyr56, and Ser129 govern whether these ligands behave as LasR activators or inhibitors. Using this knowledge, we propose a model for the modulation of LasR by AHL analogs—encompassing a subtly different interaction with the binding pocket to a global change in LasR conformation. PMID:25242287

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

    PubMed

    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.

  9. 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.

    PubMed

    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.

  10. Antimalarial Cyclic Peroxide Lactones.

    DTIC Science & Technology

    1987-05-31

    solution was extracted with methylene chloride. The extracts were washed with saturated sodium bicarbonate and saturated sodium chloride solutions and...and the filtrate was evaporated in vacuo. The residue was added with water and extracted with methylene dichloride, dried over anhydrous magnesium...the resulting oil was extracted with methylene dichloride, washed with HCl, water, sodium bicarbonate and water, dried over anhydrous magnesium

  11. Growth Inhibitory, Bactericidal, and Morphostructural Effects of Dehydrocostus Lactone from Magnolia sieboldii Leaves on Antibiotic-Susceptible and -Resistant Strains of Helicobacter pylori

    PubMed Central

    Lee, Hyun-Kyung; Song, Ha Eun; Lee, Haeng-Byung; Kim, Cheol-Soo; Koketsu, Mamoru; Thi My Ngan, Luong; 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. PMID:24747984

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

    PubMed Central

    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

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

    PubMed

    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

  14. Simultaneous quantitative profiling of N-acyl-L-homoserine lactone and 2-alkyl-4(1H)-quinolone families of quorum-sensing signaling molecules using LC-MS/MS.

    PubMed

    Ortori, Catharine A; Dubern, Jean-Frédéric; Chhabra, Siri Ram; Cámara, Miguel; Hardie, Kim; Williams, Paul; Barrett, David A

    2011-01-01

    An LC-MS/MS method, using positive mode electrospray ionization, for the simultaneous, quantitative and targeted profiling of the N-acyl-L-homoserine lactone (AHL) and 2-alkyl 4-(1H)-quinolone (AQ) families of bacterial quorum-sensing signaling molecules (QSSMs) is presented. This LC-MS/MS technique was applied to determine the relative molar ratios of AHLs and AQs produced by Pseudomonas aeruginosa and the consequences of mutating individual or multiple QSSM synthase genes (lasI, rhlI, pqsA) on AHL and AQ profiles and concentrations. The AHL profile of P. aeruginosa was dominated by N-butanoyl-L-homoserine lactone (C4-HSL) with lesser concentrations of N-hexanoyl-L-homoserine lactone (C6-HSL) and 3-oxo-substituted longer chain AHLs including N-(3-oxodecanoyl)-L-homoserine lactone (3-oxo-C10-HSL) and N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL). The AQ profile of P. aeruginosa comprised the C7 and C9 long alkyl chain AQs including 2-heptyl-4-hydroxyquinoline (HHQ), 2-nonyl-4-hydroxyquinoline, the "pseudomonas quinolone signal" (2-heptyl-3-hydroxy-4-quinolone) and the N-oxides, 2-heptyl-4-hydroxyquinoline N-oxide and 2-nonyl-4-hydroxyquinoline N-oxide. Application of the method showed significant effects of growth medium type on the ratio and the nature of the QSSMs synthesized and the dramatic effect of single, double and triple mutations in the P. aeruginosa QS synthase genes. The LC-MS/MS methodology is applicable in organisms where either or both AHL and AQ QSSMs are produced and can provide comprehensive profiles and concentrations from a single sample.

  15. [Activation of the bioluminescence of the sensor Escherichia coli strains used for detecting N-acyl-homoserine lactones in the presence of nitrofurans and NO generators].

    PubMed

    Zaĭtseva, Iu V; Granik, V G; Belik, A S; Koksharova, O A; Khmel', I A

    2010-01-01

    Nitrofurans (nitrofurazone, nitrofurantoin, furazidin, nifuroxazide), and nitric oxide generators (sodium nitroprusside and isosorbide mononitrate) in subinhibitory concentrations were shown to significantly increase the bioluminescence of the sensor Escherichia coli strains used for detecting N-acyl-homoserine lactones, signaling molecules of Quorum Sensing (QS) regulatory systems. The highest activation of bioluminescence (up to 250-400 fold) was observed in the presence of nitrofurazone on E. coli DH5alpha biosensors containing lux-reporter plasmids pSB401 or pSB536. However, this activation was not specifically associated with the functioning of QS systems. We suggest that the effect observed results from a direct action of nitrofurans and NO donors on the process of bioluminescence. The data indicate the necessity of using the biosensors that make it possible to detect specific effects of substances tested on QS regulation.

  16. Enhanced activity of galactono-1,4-lactone dehydrogenase and ascorbate-glutathione cycle in mitochondria from complex III deficient Arabidopsis.

    PubMed

    Zsigmond, Laura; Tomasskovics, Bálint; Deák, Veronika; Rigó, Gábor; Szabados, László; Bánhegyi, Gábor; Szarka, András

    2011-08-01

    The mitochondrial antioxidant homeostasis was investigated in Arabidopsis ppr40-1 mutant, which presents a block of electron flow at complex III. The activity of the ascorbate biosynthetic enzyme, L-galactono-1,4-lactone dehydrogenase (EC 1.3.2.3) (GLDH) was elevated in mitochondria isolated from mutant plants. In addition increased activities of the enzymes of Foyer-Halliwell-Asada cycle and elevated glutathione (GSH) level were observed in the mutant mitochondria. Lower ascorbate and ascorbate plus dehydroascorbate contents were detected at both cellular and mitochondrial level. Moreover, the more oxidized mitochondrial redox status of ascorbate in the ppr40-1 mutant indicated that neither the enhanced activity of GLDH nor Foyer-Halliwell-Asada cycle could compensate for the enhanced ascorbate consumption in the absence of a functional respiratory chain.

  17. In vitro cytotoxicity of Mokko lactone in human leukemia HL-60 cells: induction of apoptotic cell death by mitochondrial membrane potential collapse.

    PubMed

    Yun, Y G; Oh, H; Oh, G S; Pae, H O; Choi, B M; Kwon, J W; Kwon, T O; Jang, S I; Chung, Hun-Taeg

    2004-08-01

    We studied the effect of mokko lactone (ML) isolated from the roots of Saussurea lappa (Compositae), a plant that is used for medicinal purposes in Korea, on the induction of apoptosis in human leukemia HL-60 cells. ML was cytotoxic to HL-60 cells, and this cytotoxic effect of ML appears to be attributable to its induction of apoptotic cell death, as ML induced nuclear morphologic changes and internucleosomal DNA fragmentation and increased the proportion of Annexin V-positive cells and the activity of caspase-3. Further studies revealed that the induction of apoptosis by ML was associated with the loss of mitochondrial membrane potential. Collectively, our results suggest that apoptosis induced by ML in HL-60 cells was executed by a collapse of mitochondrial membrane potential followed by the activation of caspase-3. This is the first report on the mechanism of apoptosis-inducing effect of ML.

  18. Diversity and Distribution of N-Acylhomoserine Lactone (AHL)-Degrading Activity and AHL-Lactonase (AiiM) in Genus Microbacterium

    PubMed Central

    Wang, Wen-Zhao; Morohoshi, Tomohiro; Someya, Nobutaka; Ikeda, Tsukasa

    2012-01-01

    N-Acylhomoserine lactone (AHL)-degrading enzyme, AiiM, was identified from the potato leaf-associated Microbacterium testaceum StLB037. In this study, we cloned eight aiiM gene homologues from other AHL-degrading Microbacterium strains. The similarity of the chromosomal locus of the aiiM gene is associated with the phylogenetic classification based on 16S rRNA. Degenerate PCR revealed that the aiiM gene was only conserved in AHL-degrading Microbacterium strains, but not in fifteen Microbacterium type strains or two Microbacterium isolates from other plants. These results suggested that the high level of AHL-degrading activity in Microbacterium strains was caused by the aiiM gene encoded on their chromosome. PMID:22446311

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

    PubMed

    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.

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

    PubMed

    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.

  1. Synthesis and structure-activity relationships of guaiane-type sesquiterpene lactone derivatives with respect to inhibiting NO production in lipopolysaccharide-induced RAW 264.7 macrophages.

    PubMed

    Chen, Hao; Chen, Bing-Yang; Liu, Chun-Ting; Zhao, Zeng; Shao, Wen-Hao; Yuan, Hu; Bi, Kai-Jian; Liu, Jiang-Yun; Sun, Qing-Yan; Zhang, Wei-Dong

    2014-08-18

    A guaiane framework was scaffolded by photochemical rearrangement reactions using α-santonin 1 as a starting material. Then, using a series of reactions, we synthesized the guaiane-type sesquiterpene lactone 5 in high yield. The inhibitory activities of compound 5 and of a series of derivatives on nitric oxide (NO) release were evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Compounds 6g, 7h, 7i, 7k and 8g, exhibited significant inhibitory effects on NO production, with IC50 values of 14.8, 22.3, 18.3, 17.4 and 7.0 μM, respectively. Their cytotoxicities were also estimated using an MTT assay. The structure-activity relationships of these compounds were also discussed.

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

    PubMed

    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.

  3. Drug absorption in vitro model: filter-immobilized artificial membranes. 2. Studies of the permeability properties of lactones in Piper methysticum Forst.

    PubMed

    Avdeef, A; Strafford, M; Block, E; Balogh, M P; Chambliss, W; Khan, I

    2001-12-01

    The assessment of transport properties of 23 drug and natural product molecules was made using the in vitro model based on filter-immobilized artificial membranes (filter-IAM), assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 h). The highly mobile kava lactones permeated in the order dihydromethisticin (40)>yangonin (37)>kavain (34)>methisticin (32)>desmethoxyyangonin (26), the numbers in parentheses being the measured effective permeabilities in units of 10(-6) cm/s. By comparison, commercial drugs ranked: phenazopyridine (35)>testosterone (19)>propranolol (13)>ketoconazole (6.3)>piroxicam (2.2)>caffeine (1.7)>metoprolol (0.8)>terbutaline (0.01). In addition to permeability measurements, membrane retention of compounds was determined. Yangonin, desmethoxyyangonin, ketoconazole, and phenazopyridine were more than 60% retained by the artificial membranes containing phospholipids. Stirring during assay significantly increased the observed permeabilities for highly mobile molecules, but had minimal impact on the poorly permeable molecules. The influence of hydrogen bonding was explored by determining permeabilities using filters coated with dodecane free of phospholipids. In the filter-IAM method, concentrations were determined by microtitre plate UV spectrophotometry and by LC-MS. Higher-throughput was achieved with direct UV by the use of 96-well microtitre plate formats and with LC-MS by the use of cassette dosing (five-in-one).

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

    PubMed

    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.

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

    PubMed

    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.

  6. N-Acyl-Homoserine Lactone Confers Resistance toward Biotrophic and Hemibiotrophic Pathogens via Altered Activation of AtMPK61[C][W

    PubMed Central

    Schikora, Adam; Schenk, Sebastian T.; Stein, Elke; Molitor, Alexandra; Zuccaro, Alga; Kogel, Karl-Heinz

    2011-01-01

    Pathogenic and symbiotic bacteria rely on quorum sensing to coordinate the collective behavior during the interactions with their eukaryotic hosts. Many Gram-negative bacteria use N-acyl-homoserine lactones (AHLs) as signals in such communication. Here we show that plants have evolved means to perceive AHLs and that the length of acyl moiety and the functional group at the γ position specify the plant’s response. Root treatment with the N-3-oxo-tetradecanoyl-L-homoserine lactone (oxo-C14-HSL) reinforced the systemic resistance to the obligate biotrophic fungi Golovinomyces orontii in Arabidopsis (Arabidopsis thaliana) and Blumeria graminis f. sp. hordei in barley (Hordeum vulgare) plants. In addition, oxo-C14-HSL-treated Arabidopsis plants were more resistant toward the hemibiotrophic bacterial pathogen Pseudomonas syringae pv tomato DC3000. Oxo-C14-HSL promoted a stronger activation of mitogen-activated protein kinases AtMPK3 and AtMPK6 when challenged with flg22, followed by a higher expression of the defense-related transcription factors WRKY22 and WRKY29, as well as the PATHOGENESIS-RELATED1 gene. In contrast to wild-type Arabidopsis and mpk3 mutant, the mpk6 mutant is compromised in the AHL effect, suggesting that AtMPK6 is required for AHL-induced resistance. Results of this study show that AHLs commonly produced in the rhizosphere are crucial factors in plant pathology and could be an agronomic issue whose full impact has to be elucidated in future analyses. PMID:21940998

  7. The Acyl-Homoserine Lactone Synthase YenI from Yersinia enterocolitica Modulates Virulence Gene Expression in Enterohemorrhagic Escherichia coli O157:H7

    PubMed Central

    Nguyen, Y N.; Sheng, Haiqing; Dakarapu, Rambabu; Falck, John R.; Hovde, Carolyn J.

    2013-01-01

    The human pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 colonizes the rectoanal junction (RAJ) in cattle, its natural reservoir. Colonization at the RAJ poses a serious risk for fecal shedding and contamination of the environment. We previously demonstrated that EHEC senses acyl-homoserine lactones (AHLs) produced by the microbiota in the rumen to activate the gad acid resistance genes necessary for survival through the acidic stomachs in cattle and to repress the locus of enterocyte effacement (LEE) genes important for colonization of the RAJ, but unnecessary in the rumen. Devoid of AHLs, the RAJ is the prominent site of colonization of EHEC in cattle. To determine if the presence of AHLs in the RAJ could repress colonization at this site, we engineered EHEC to express the Yersinia enterocolitica AHL synthase gene yenI, which constitutively produces AHLs, to mimic a constant exposure of AHLs in the environment. The yenI+ EHEC produces oxo-C6-homoserine lactone (oxo-C6-HSL) and had a significant reduction in LEE expression, effector protein secretion, and attaching and effacing (A/E) lesion formation in vitro compared to the wild type (WT). The yenI+ EHEC also activated expression of the gad genes. To assess whether AHL production, which decreases LEE expression, would decrease RAJ colonization by EHEC, cattle were challenged at the RAJ with WT or yenI+ EHEC. Although the yenI+ EHEC colonized the RAJ with efficiency equal to that of the WT, there was a trend for the cattle to shed the WT strain longer than the yenI+ EHEC. PMID:23980115

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

    SciTech Connect

    Miao, Chunjuan; Liu, Fang; Zhao, Qian; Jia, Zhenhua; Song, Shuishan

    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.

  9. Ascorbate-synthesizing system in rat liver microsomes. II. A peptide-bound flavin as the prosthetic group of L-gulono-gamma-lactone oxidase.

    PubMed

    Nakagawa, H; Asano, A; Sato, R

    1975-01-01

    L-Gulono-gamma-lactone oxidase [EC 1.1.3.8] was purified 80-fold from rat liver microsomes. In confirmation of our previous finding with a cruder preparation, the purified enzyme was shown to contain an L-gulono-gamma-lactone-reducible pigment as a prosthetic group. This pigment was not liberated from the protein by acid ammonium sulfate, 10% trichloroacetic acid or 2 M area, but was effectively released by proteolytic digestion. The pigment thus released showed a reduced-minus-oxidized difference spectrum characteristic of a flavin compound. The pigment was liberated from a trichloroacetic acid-treated preparation of the enzyme by pronase digestion and purified by Florisil column chromatography and paper chromatography. The absorption spectrum as well as the fluorescence emission and excitation spectra of the purified pigment indicated that it was actually a flavin peptide. It was, however, different not only from FMN but also from flavin peptides isolated from other sources such as succinate dehydrogenase [EC 1.3.99.1] and monoamine oxidase [EC 1.4.3.4] as regards the pH dependence of fluorescence intensity and the Rf value on thin-layer chromatography. A preliminary analysis showed that the purified flavin compound contained several amino acid residues. Alkaline photolysis of the purified flavin peptide suggested that the isoalloxazine ring of the flavin is involved in its binding to the peptide. The hypsochromic shift of the absorption peak in the near-ultraviolet region suggested further that the linkage between the flavin and the peptide may be mediated by the 8-methyl group of the isoalloxazine nucleus. It can be concluded that the prosthetic group of gulonolactone oxidase is a flavin which is covalently bound to the enzyme protein.

  10. Mechanism of chemical degradation and determination of solubility by kinetic modeling of the highly unstable sesquiterpene lactone nobilin in different media.

    PubMed

    Thormann, Ursula; De Mieri, Maria; Neuburger, Markus; Verjee, Sheela; Altmann, Peter; Hamburger, Matthias; Imanidis, Georgios

    2014-10-01

    The objective of this work was first to investigate the chemical degradation of the sesquiterpene lactone nobilin and determine its solubility under conditions of concurrent degradation for partially amorphous starting material; second, to determine the effect of biorelevant media used in the in vitro measurement of intestinal absorption on degradation and solubility of nobilin. Purely aqueous medium (aq-TMCaco ), fasted and fed state simulated intestinal fluid (FaSSIF-TMCaco and FeSSIF-TMCaco ), and two liposomal formulations (LiposomesFaSSIF and LiposomesFeSSIF ) with the same lipid concentration as FaSSIF-TMCaco and FeSSIF-TMCaco were used. Degradation products were identified by nuclear magnetic resonance and X-ray crystallography and the order of reaction kinetics was determined. Solubility was deduced with a mathematical model encompassing dissolution, degradation, and reprecipitation kinetics that took into account particle size distribution of the solid material. Degradation mechanism of nobilin involved water-catalyzed opening of the lactone ring and transannular cyclization resulting in five degradation products. Degradation followed first-order kinetics in aq-TMCaco and FaSSIF-TMCaco , and higher-order kinetics in FeSSIF-TMCaco and the two liposomal formulations, whereas degradation in the latter media was diminished. Solubility of nobilin increased in the order: aq-TMCaco < FaSSIF-TMCaco , < LiposomesFaSSIF < FeSSIF-TMCaco < LiposomesFeSSIF . Improvement of stability and solubility was consistent with the incorporation of the nobilin molecule into colloidal lipid particles. The developed kinetic model is proposed to be a useful tool for deducing solubility under dynamic conditions.

  11. Acyl homoserine lactone changes the abundance of proteins and the levels of organic acids associated with stationary phase in Salmonella Enteritidis.

    PubMed

    de Almeida, Felipe Alves; Pimentel-Filho, Natan de Jesus; Carrijo, Lanna Clícia; Bento, Cláudia Braga Pereira; Baracat-Pereira, Maria Cristina; Pinto, Uelinton Manoel; de Oliveira, Leandro Licursi; Vanetti, Maria Cristina Dantas

    2017-01-01

    Quorum sensing (QS) is cell-cell communication mechanism mediated by signaling molecules known as autoinducers (AIs) that lead to differential gene expression. Salmonella is unable to synthesize the AI-1 acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. Our study aimed to evaluate the influence of AI-1 on the abundance of proteins and the levels of organic acids of Salmonella Enteritidis. The presence of N-dodecyl-homoserine lactone (C12-HSL) did not interfere on the growth or the total amount of extracted proteins of Salmonella. However, the abundance of the proteins PheT, HtpG, PtsI, Adi, TalB, PmgI (or GpmI), Eno, and PykF enhanced while the abundance of the proteins RplB, RplE, RpsB, Tsf, OmpA, OmpC, OmpD, and GapA decreased when Salmonella Enteritidis was anaerobically cultivated in the presence of C12-HSL. Additionally, the bacterium produced less succinic, lactic, and acetic acids in the presence of C12-HSL. However, the concentration of extracellular formic acid reached 20.46 mM after 24 h and was not detected when the growth was in the absence of AI-1. Considering the cultivation period for protein extraction, their abundance, process and function, as well as the levels of organic acids, we observed in cells cultivated in presence of C12-HSL a correlation with what is described in the literature as entry into the stationary phase of growth, mainly related to nitrogen and amino acid starvation and acid stress. Further studies are needed in order to determine the specific role of the differentially abundant proteins and extracellular organic acids secreted by Salmonella in the presence of quorum sensing signaling molecules.

  12. Quantitative analysis of beta-d-glucopyranoside of 3-methyl-4-hydroxyoctanoic acid, a potential precursor to cis-oak lactone, in oak extracts using liquid chromatography-tandem mass spectrometry based stable isotope dilution analysis.

    PubMed

    Fudge, Anthea L; Elsey, Gordon M; Hayasaka, Yoji; Wilkinson, Kerry L

    2008-12-26

    The beta-D-glucopyranoside of 3-methyl-4-hydroxyoctanoic acid (glucoside), exists in oak wood and is a potential precursor to cis-oak lactone. A method for the quantification of the glucoside in extracts of oak wood using liquid chromatography-tandem mass spectrometry was developed. The [(2)H(4)]-labeled analogue of the glucoside was synthesized and used as internal standard for the method which was subsequently applied to the analysis of extracts of both American and French oak woods. The concentration of the glucoside in the extracts varied widely from less than 0.1 up to approximately 50 microg/g-oak wood. The method allowed for the quantification of the glucoside as a potential oak lactone precursor in oak woods for the first time.

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

    PubMed

    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

  14. Biosynthesis of Germacrene A Carboxylic Acid in Chicory Roots. Demonstration of a Cytochrome P450 (+)-Germacrene A Hydroxylase and NADP+-Dependent Sesquiterpenoid Dehydrogenase(s) Involved in Sesquiterpene Lactone Biosynthesis

    PubMed Central

    de Kraker, Jan-Willem; Franssen, Maurice C. R.; Dalm, Marcella C. F.; de Groot, Aede; Bouwmeester, Harro J.

    2001-01-01

    Sprouts of chicory (Cichorium intybus), a vegetable grown in the dark, have a slightly bitter taste associated with the presence of guaianolides, eudesmanolides, and germacranolides. The committed step in the biosynthesis of these compounds is catalyzed by a (+)-germacrene A synthase. Formation of the lactone ring is the postulated next step in biosynthesis of the germacrene-derived sesquiterpene lactones. The present study confirms this hypothesis by isolation of enzyme activities from chicory roots that introduce a carboxylic acid function in the germacrene A isopropenyl side chain, which is necessary for lactone ring formation. (+)-Germacrene A is hydroxylated to germacra-1(10),4,11(13)-trien-12-ol by a cytochrome P450 enzyme, and is subsequently oxidized to germacra-1(10),4,11(13)-trien-12-oic acid by NADP+-dependent dehydrogenase(s). Both oxidized germacrenes were detected as their Cope-rearrangement products elema-1,3,11(13)-trien-12-ol and elema-1,3,11(13)-trien-12-oic acid, respectively. The cyclization products of germacra-1(10),4,11(13)-trien-12-ol, i.e. costol, were also observed. The (+)-germacrene A hydroxylase is inhibited by carbon monoxide (blue-light reversible), has an optimum pH at 8.0, and hydroxylates β-elemene with a modest degree of enantioselectivity. PMID:11299372

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

    PubMed Central

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

    2004-01-01

    Quorum-sensing (QS) signals (N-acyl homoserine lactones [AHLs]) were extracted and detected from five commercially produced vacuum-packed meat samples. Ninety-six AHL-producing bacteria were isolated, and 92 were identified as Enterobacteriaceae. Hafnia alvei was the most commonly identified AHL-producing bacterium. Thin-layer chromatographic profiles of supernatants from six H. alvei isolates and of extracts from spoiling meat revealed that the major AHL species had an Rf value and shape similar to N-3-oxo-hexanoyl homoserine lactone (OHHL). Liquid chromatography-mass spectrometry (MS) (high-resolution MS) analysis confirmed the presence of OHHL in pure cultures of H. alvei. Vacuum-packed meat spoiled at the same rate when inoculated with the H. alvei wild type compared to a corresponding AHL-lacking mutant. Addition of specific QS inhibitors to the AHL-producing H. alvei inoculated in meat or to naturally contaminated meat did not influence the spoilage of vacuum-packed meat. An extracellular protein of approximately 20 kDa produced by the H. alvei wild-type was not produced by the AHL-negative mutant but was restored in the mutant when complemented by OHHL, thus indicating that AHLs do have a regulatory role in H. alvei. Coinoculation of H. alvei wild-type with an AHL-deficient Serratia proteamaculans B5a, in which protease secretion is QS regulated, caused spoilage of liquid milk. By contrast, coinoculation of AHL-negative strains of H. alvei and S. proteamaculans B5a did not cause spoilage. In conclusion, AHL and AHL-producing bacteria are present in vacuum-packed meat during storage and spoilage, but AHL does not appear to influence the spoilage of this particular type of conserved meat. Our data indicate that AHL-producing H. alvei may induce food quality-relevant phenotypes in other bacterial species in the same environment. H. alvei may thus influence spoilage of food products in which Enterobacteriaceae participate in the spoilage process. PMID:15240313

  16. 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.

    PubMed

    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

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

    PubMed

    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

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

    PubMed

    Götz-Rösch, Christine; Sieper, Tina; Fekete, Agnes; Schmitt-Kopplin, Philippe; Hartmann, Anton; Schröder, Peter

    2015-01-01

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

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

    PubMed Central

    Götz-Rösch, Christine; Sieper, Tina; Fekete, Agnes; Schmitt-Kopplin, Philippe; Hartmann, Anton; Schröder, Peter

    2015-01-01

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

  20. 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

    PubMed Central

    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

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

    PubMed

    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 <12.5 min, with excellent separation. The method 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.

  2. The transcription of l-gulono-gamma-lactone oxidase, a key enzyme for biosynthesis of ascorbate, during development of Persian sturgeon Acipenser persicus.

    PubMed

    Akbarzadeh, Arash; Farahmand, Hamid; Mahjoubi, Frouzandeh; Nematollahi, Mohammad Ali; Leskinen, Piia; Rytkönen, Kalle; Nikinmaa, Mikko

    2011-04-01

    l-Gulono-gamma-lactone oxidase (GULO) is a key enzyme for the biosynthesis of ascorbate, which is essential for several cellular functions. In the present study, mRNA expression of GULO gene was evaluated during the early development of Persian sturgeon. First, because there are no comparative studies that have established suitable quantitative real-time PCR reference genes in sturgeons for any physiological conditions, we evaluated six candidate reference genes (ACTB, RPL13, UBQ, RPL6, GAPDH and EF1A) during the early development of Persian sturgeon. The most stable mRNA expression was obtained with RPL6 and ACTB, whereas the least stable was RPL13. After normalization using RPL6, ACTB and RPL6/ACTB combination, the mRNA expression of GULO was highest at the embryonic stage (2days before hatching; P<0.05) and started to decline from hatching of larvae to the rest of the developmental time-points. This suggests that the vitamin C requirements are highest during early life stages, and it is likely that the changes in GULO mRNA expression are associated with changes in GULO enzyme activity.

  3. Haloperoxidase Mediated Quorum Quenching by Nitzschia cf pellucida: Study of the Metabolization of N-Acyl Homoserine Lactones by a Benthic Diatom

    PubMed Central

    Syrpas, Michail; Ruysbergh, Ewout; Blommaert, Lander; Vanelslander, Bart; Sabbe, Koen; Vyverman, Wim; De Kimpe, Norbert; Mangelinckx, Sven

    2014-01-01

    Diatoms are known to produce a variety of halogenated compounds, which were recently shown to have a role in allelopathic interactions between competing species. The production of these compounds is linked to haloperoxidase activity. This research, has shown that this system may also be involved in diatom-bacteria interactions via the H2O2 dependent inactivation of a type of quorum sensing (QS) molecule, i.e., N-β-ketoacylated homoserine lactones (AHLs), by a natural haloperoxidase system from the benthic diatom Nitzschia cf pellucida. The AHL degradation pathway towards corresponding halogenated derivatives was elucidated via HPLC-MS analysis and the synthesis of a broad series of novel halogenated AHL analogues as reference compounds. Furthermore, their biological activity as quorum sensing modulators was directly compared and evaluated against a series of naturally occurring β-keto-AHLs. It has been demonstrated that the loss of the QS activity results from the final cleavage of the halogenated N-acyl chain of the signal molecules. PMID:24445305

  4. Inhibitory effect of sesquiterpene lactones from Saussurea lappa on tumor necrosis factor-alpha production in murine macrophage-like cells.

    PubMed

    Cho, J Y; Park, J; Yoo, E S; Baik, K U; Jung, J H; Lee, J; Park, M H

    1998-10-01

    Total methanol extract of Saussurea lappa radix (Compositae) showed potent inhibitory effect on the production of tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, in murine macrophage-like cell (RAW264.7 cells) in our previous screening studies on 120 Korean medicinal plants. The activity-guided purification of the plant resulted in the isolation of three components. The chemical structures of the components isolated were established by spectroscopic analyses as sesquiterpene lactones [cynaropicrin (1), reynosin (2), and santamarine (3)]. These three compounds inhibited TNF-alpha production in a dose-dependent manner. The molar concentrations of cynaropicrin, reynosin, and santamarine producing 50% inhibition (IC50) of TNF-alpha production were 2.86 micrograms/ml (8.24 microM), 21.7 micrograms/ml (87.4 microM), and 26.2 micrograms/ml (105 microM), respectively. However, treatment with sulphydryl (SH) compounds such as L-cysteine, dithiothreitol, and 2-mercaptoethanol abrogated the inhibitory effect of cynaropicrin on TNF-alpha production. Therefore, we conclude that the principal inhibitory component of Saussurea lappa is cynaropicrin and its inhibitory effect is mediated through conjugation with SH-groups of target proteins.

  5. Synthesis of sugars embodying conjugated carbonyl systems and related triazole derivatives from carboxymethyl glycoside lactones. Evaluation of their antimicrobial activity and toxicity.

    PubMed

    Xavier, Nuno M; Goulart, Margarida; Neves, Ana; Justino, Jorge; Chambert, Stéphane; Rauter, Amélia P; Queneau, Yves

    2011-01-15

    The synthesis of a series of pyranoid derivatives comprising a conjugated carbonyl function and related triazole derivatives, structurally suitable for bioactivity evaluation, was achieved in few steps starting from readily available carboxymethyl glycoside lactones (CMGL). 3-Enopyranosid-2-uloses were generated by oxidation/elimination of tri-O-acylated 2-hydroxy pyranosides. Subsequent Wittig olefination provided stereoselectively 2-C-branched-chain conjugated dienepyranosides with (E)-configuration around the exocyclic double bond. A heterogeneous CuI/Amberlyst-catalyzed 'click' chemistry protocol was used to convert glycosides bearing a propargyl moiety into the corresponding 1,2,3-triazoles. These new molecules were screened for their in vitro antibacterial and antifungal activities and those containing conjugated carbonyl systems demonstrated the best efficacy. (N-Dodecylcarbamoyl)methyl enone glycerosides were the most active ones among the enones tested. The α-anomer displayed very strong activities against Bacillus cereus and Bacillus subtilis and strong activity toward Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The corresponding β-anomer presented a very strong inhibitory effect against two fungal species (Aspergillus niger and P. aurantiogriseum). (N-Dodecyl-/N-propargyl/or N-benzylcarbamoyl)methyl dienepyranosides exhibited selectively a strong activity toward E. faecalis. Further acute toxicity evaluation indicated low toxic effect of the (N-dodecylcarbamoyl)methyl enone glyceroside α-anomer and of the carbamoylmethyl dienepyranosides N-protected with propargyl or benzyl groups.

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

    PubMed Central

    Paul, Diby

    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. PMID:25147787

  7. L-gulono-γ-lactone oxidase expression and vitamin C synthesis in the brain and kidney of the African lungfish, Protopterus annectens.

    PubMed

    Ching, Biyun; Ong, Jasmine L Y; Chng, You Rong; Chen, Xiu Ling; Wong, Wai P; Chew, Shit F; Ip, Yuen K

    2014-08-01

    This study aimed to test the hypothesis that the brain of Protopterus annectens expressed L-gulono-γ-lactone oxidase (gulo/Gulo), the enzyme catalyzing the last step of ascorbate biosynthesis, and could maintain high concentrations of ascorbate during estivation. We cloned and sequenced gulo from the kidney of P. annectens and performed quantitative PCR to determine its mRNA expression in kidney and brain. Gulo activity was assayed and its protein abundance was determined by Western blot using custom-made anti-Gulo antibody. Effects of estivation on concentrations of ascorbate and dehydroascorbate in the kidney and brain were also determined. Both brain and kidney, but not liver, of P. annectens expressed gulo/Gulo. Desiccation induced P. annectens to estivate, and 6 mo of estivation led to drastic decreases in gulo/Gulo expression and ascorbate concentration in the kidney. However, high concentrations of ascorbate and ascorbate + dehydroascorbate were maintained in the brain during estivation, probably resulting from in situ ascorbate synthesis. Control fish were placed in freshwater, where they were fully active in a favorable environment unlike estivation on land. The ability to synthesize ascorbate to ameliorate oxidative stress directly in the brain might contribute to the ability of P. annectens to undergo prolonged estivation on land.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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 < 0.05) relationship with the Chlorophyta sp. settleability, and showed a positive correlation, indicating that aromatic proteins helped aggregate 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. [Reductive effect of the sesquiterpenic lactone "Helenalin " and its metallic derivatives in the formation of the estradiol receptor complex in breast tumor tissue].

    PubMed

    Salazar Esquivel, E L; Tellez, M C; Calzada, L

    1995-01-01

    Chemotherapy for systemic therapy in breast cancer has been widely used, and has been supported by many varied compounds with different origins and different compositions. Nevertheless, all of them produce several side adverse effects which must be taken into account. For this reason we must study new possibilities in which the administered drug acts selectively on the tumour cell without injuring healthy tissue. For studying its effect, a gamma lactone called "Helenaline" and its metalic derivates He-Co, He-Hg and He-Cu were studied, which chemical composition allows them to react with -SH residues present in the tumour cell receptors, which when interspaced by a previous reaction, could modify its structural composition and finally its affinity by the hormone. The inhibition effect for formation of estradiol-receptor complex in breast tumour tissue using Helenaline 12 n M and 126 n M was studied, obtaining 14% and 56% inhibition effect respectively. When He-Co, He-Hg and He-Cu effect was studied, this effect was raised obtaining 11%, 10.5% and 60% with 12 nM and 44.5%, 74.4% and 86% with 126 nM respectively.

  13. Determination of D-glucaric acid and/or D-glucaro-1,4-lacton in different apple varieties through hydrophilic interaction chromatography.

    PubMed

    Xie, Baogang; Liu, Yalan; Zou, Huiqin; Son, Yong; Wang, Huiyun; Wang, Haipeng; Shao, Jianghua

    2016-07-15

    d-Glucaric acid (GA) derivatives exhibit anti-cancerogenic properties in vivo in apples, but quantitative information about these derivatives is limited. Hydrophilic interaction-based HPLC with ultraviolet detection or mass spectrometry was developed to quantify GA and/or D-glucaro-1,4-lacton (1,4-GL) in apples. Although the formation of 1,4-GL from GA could be the prerequisite to exert biological effects in vivo, only a small portion of GA (<5%) was identified and converted to 1,4-GL in the rat stomach. The 1,4-GL content in apples ranged from 0.3 mg/g to 0.9 mg/g, and this amount can substantiate health claims associated with apples. The amount of 1,4-GL was 1.5 times higher in Gala and the ratio of 1,4-GL to GA was lower in Green Delicious apples than those in the other varieties. Our findings suggested that the variety and maturity of apples at harvest are factors that determine 1,4-GL content.

  14. Extracts of three Laserpitium L. species and their principal components laserpitine and sesquiterpene lactones inhibit microbial growth and biofilm formation by oral Candida isolates.

    PubMed

    Popović, Višnja; Stojković, Dejan; Nikolić, Miloš; Heyerick, Arne; Petrović, Silvana; Soković, Marina; Niketić, Marjan

    2015-04-01

    Antimicrobial properties of extracts of underground parts of three Laserpitium L. (Apiaceae) species, namely Laserpitium latifolium L., Laserpitium zernyi Hayek and Laserpitium ochridanum Micevski, were investigated. The investigated species are widely used as functional foods, as spices and for preparations in traditional medicine for treating complaints connected with infection and inflammation. Furthermore, antimicrobial and antibiofilm effects of laserpitine, the most abundant compound in the chloroform extract of L. latifolium, and guaianolide sesquiterpene lactones, such as, isomontanolide, montanolide and tarolide, principal components of the extracts of L. zernyi and L. ochridanum were assessed. The antimicrobial activity was tested using the microdilution method against five pathogenic bacteria and five fungi, as well as in the microplate biofilm assay on two Candida clinical isolates (C. albicans and C. krusei). Among the extracts, L. latifolium showed the most prominent activity. Isolated metabolites exerted higher effects against fungal than against bacterial strains, isomontanolide being the most active. Interestingly, all constituents showed higher potential on inhibition of biofilm formation than fluconazole, a reference compound. Tested metabolites may be good novel agents with high antifungal and antibacterial potential that might find practical applications in food industry as food preservatives in order to retard the growth of food spoiling microbes, but only after detailed safety assessments.

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

    PubMed

    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.

  16. EM23, a natural sesquiterpene lactone, targets thioredoxin reductase to activate JNK and cell death pathways in human cervical cancer cells

    PubMed Central

    Chen, Wen-Bo; Wang, Guo-Cai; Ma, Dong-Lei; Wong, Nai Sum; Xiao, Hao; Liu, Qiu-Ying; Zhou, Guang-Xiong; Li, Yao-Lan; Li, Man-Mei; Wang, Yi-Fei; Liu, Zhong

    2016-01-01

    Sesquiterpene lactones (SLs) are the active constituents of a variety of medicinal plants and found to have potential anticancer activities. However, the intracellular molecular targets of SLs and the underlying molecular mechanisms have not been well elucidated. In this study, we observed that EM23, a natural SL, exhibited anti-cancer activity in human cervical cancer cell lines by inducing apoptosis as indicated by caspase 3 activation, XIAP downregulation and mitochondrial dysfunction. Mechanistic studies indicated that EM23-induced apoptosis was mediated by reactive oxygen species (ROS) and the knockdown of thioredoxin (Trx) or thioredoxin reductase (TrxR) resulted in a reduction in apoptosis. EM23 attenuated TrxR activity by alkylation of C-terminal redox-active site Sec498 of TrxR and inhibited the expression levels of Trx/TrxR to facilitate ROS accumulation. Furthermore, inhibition of Trx/TrxR system resulted in the dissociation of ASK1 from Trx and the downstream activation of JNK. Pretreatment with ASK1/JNK inhibitors partially rescued cells from EM23-induced apoptosis. Additionally, EM23 inhibited Akt/mTOR pathway and induced autophagy, which was observed to be proapoptotic and mediated by ROS. Together, these results reveal a potential molecular mechanism for the apoptotic induction observed with SL compound EM23, and emphasize its putative role as a therapeutic agent for human cervical cancer. PMID:26758418

  17. SdiA, an N-Acylhomoserine Lactone Receptor, Becomes Active during the Transit of Salmonella enterica through the Gastrointestinal Tract of Turtles

    PubMed Central

    Soares, Jitesh A.; Ellermeier, Craig D.; Altier, Craig; Lawhon, Sara D.; Adams, L. Garry; Konjufca, Vjollca; Curtiss, Roy; Slauch, James M.; Ahmer, Brian M. M.

    2008-01-01

    Background LuxR-type transcription factors are typically used by bacteria to determine the population density of their own species by detecting N-acylhomoserine lactones (AHLs). However, while Escherichia and Salmonella encode a LuxR-type AHL receptor, SdiA, they cannot synthesize AHLs. In vitro, it is known that SdiA can detect AHLs produced by other bacterial species. Methodology/Principal Findings In this report, we tested the hypothesis that SdiA detects the AHL-production of other bacterial species within the animal host. SdiA did not detect AHLs during the transit of Salmonella through the gastrointestinal tract of a guinea pig, a rabbit, a cow, 5 mice, 6 pigs, or 12 chickens. However, SdiA was activated during the transit of Salmonella through turtles. All turtles examined were colonized by the AHL-producing species Aeromonas hydrophila. Conclusions/Significance We conclude that the normal gastrointestinal microbiota of most animal species do not produce AHLs of the correct type, in an appropriate location, or in sufficient quantities to activate SdiA. However, the results obtained with turtles represent the first demonstration of SdiA activity in animals. PMID:18665275

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

    PubMed

    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.

  19. Cytochrome P450s from Cynara cardunculus L. CYP71AV9 and CYP71BL5, catalyze distinct hydroxylations in the sesquiterpene lactone biosynthetic pathway.

    PubMed

    Eljounaidi, Kaouthar; Cankar, Katarina; Comino, Cinzia; Moglia, Andrea; Hehn, Alain; Bourgaud, Frédéric; Bouwmeester, Harro; Menin, Barbara; Lanteri, Sergio; Beekwilder, Jules

    2014-06-01

    Cynara cardunculus (Asteraceae) is a cross pollinated perennial crop which includes the two cultivated taxa globe artichoke and cultivated cardoon. The leaves of these plants contain high concentrations of sesquiterpene lactones (STLs) among which cynaropicrin is the most represented, and has recently attracted attention because of its therapeutic potential as anti-tumor and anti-photoaging agent. Costunolide is considered the common precursor of the STLs and three enzymes are involved in its biosynthetic pathway: i.e. the germacrene A synthase (GAS), the germacrene A oxidase (GAO) and the costunolide synthase (COS). Here we report on the isolation of two P450 genes, (i.e. CYP71AV9 and CYP71BL5), in a set of ∼19,000 C. cardunculus unigenes, and their functional characterization in yeast and in planta. The metabolite analyses revealed that the co-expression of CYP71AV9 together with GAS resulted in the biosynthesis of germacra-1(10),4,11(13)-trien-12-oic acid in yeast. The co-expression of CYP71BL5 and CYP71AV9 with GAS led to biosynthesis of the free costunolide in yeast and costunolide conjugates in Nicotiana benthamiana, demonstrating their involvement in STL biosynthesis as GAO and COS enzymes. The substrate specificity of CYP71AV9 was investigated by testing its ability to convert amorpha-4,11-diene, (+)-germacrene D and cascarilladiene to their oxidized products when co-expressed in yeast with the corresponding terpene synthases.

  20. In situ quantitation of the spatial scale of calling distances and population density-independent N-acylhomoserine lactone-mediated communication by rhizobacteria colonized on plant roots.

    PubMed

    Gantner, Stephan; Schmid, Michael; Dürr, Christine; Schuhegger, Regina; Steidle, Anette; Hutzler, Peter; Langebartels, Christian; Eberl, Leo; Hartmann, Anton; Dazzo, Frank B

    2006-05-01

    We used computer-assisted microscopy at single cell resolution to quantify the in situ spatial scale of N-acylhomoserine lactone (AHL)-mediated cell-to-cell communication of Pseudomonas putida colonized on tomato and wheat root surfaces. The results of this in situ quantification study on close-to-natural surfaces challenge the conventional view of a quorum group requirement of high cell densities for this type of bacterial communication. In situ image analysis indicated that the effective 'calling distance' on root surfaces was most frequent at 4-5 microm, extended to 37 microm in the root tip/elongation zone and further out to 78 microm in the root hair zone. The spatial scale of these calling distances is very long-range in proportion to the size of individual bacteria. Geostatistical modeling analysis implicated the importance of AHL-gradients mediating effective communication between remote cells. We conclude that AHL-mediated cell-to-cell communication occurs not only within dense populations, but also in very small groups and over long ranges between individual bacteria, and therefore this cellular activity is more commonplace and effective than hitherto predicted. We propose that this cell-to-cell communication is governed more by the in situ spatial proximity of cells within AHL-gradients than the requirement for a quorum group of high population density.

  1. Selection of the N-Acylhomoserine Lactone-Degrading Bacterium Alteromonas stellipolaris PQQ-42 and of Its Potential for Biocontrol in Aquaculture.

    PubMed

    Torres, Marta; Rubio-Portillo, Esther; Antón, Josefa; Ramos-Esplá, Alfonso A; Quesada, Emilia; Llamas, Inmaculada

    2016-01-01

    The production of virulence factors by many pathogenic microorganisms depends on the intercellular communication system called quorum sensing, 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 signaling 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 Vibrio 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.

  2. Selection of the N-Acylhomoserine Lactone-Degrading Bacterium Alteromonas stellipolaris PQQ-42 and of Its Potential for Biocontrol in Aquaculture

    PubMed Central

    Torres, Marta; Rubio-Portillo, Esther; Antón, Josefa; Ramos-Esplá, Alfonso A.; Quesada, Emilia; Llamas, Inmaculada

    2016-01-01

    The production of virulence factors by many pathogenic microorganisms depends on the intercellular communication system called quorum sensing, 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 signaling 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 Vibrio 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. PMID:27242684

  3. Resorcylic acid lactone L-783,277 inhibits the growth of the human adrenal cancer cell line H295R in vitro.

    PubMed

    Lawnicka, H; Kowalewicz-Kulbat, M; Sicinska, P; Altmann, K H; Hofmann, T; Stepien, H

    2009-01-01

    The resorcylic acid lactone L-783,277, isolated from a Phoma sp. (ATCC 74403), is a potent and specific inhibitor of MEK (Map kinase kinase) that exerts very interesting pharmacological activities including anti-neoplastic properties. However, the role of this compound in the regulation of endocrine-related cancer cell growth and tumor progression remains unknown. In the present study we have evaluated the effect of L-783,277 on the viability, proliferation and cell cycle of the human adrenocortical carcinoma cell line H295R. L-783,277 inhibited viability (IC50 of 22 microM) and cell proliferation (IC50 of 21 microM) of H295R. At concentrations of 10(-6)-10(-8)M this effect was associated with the accumulation of H295R cells in S-phase, whereas at concentrations of 10(-9)-10(-10)M a prolonged G1-phase and reduced transition into S-phase were observed. Our findings demonstrate for the first time the anti-proliferative action of L-783,277 on the human adrenocortical H295R cell line.

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

    PubMed

    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.

  5. 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.

    PubMed

    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.

  6. Sesquiterpene lactone content and overall quality of fresh-cut witloof chicory (Cichorium intybus L. var. foliosum Hegi) as affected by different washing procedures.

    PubMed

    Wulfkuehler, Sabine; Gras, Claudia; Carle, Reinhold

    2013-08-14

    Fresh-cut chicory was produced by four different processing lines testing cold and warm water (4/45 °C, 120 s) and cold water containing cysteine (0.5 mM) against an unwashed control. Levels of sesquiterpene lactones (SLs), sensory, and color attributes as well as O2 and CO2 levels in the modified atmosphere of the fresh-cut produce stored in consumer-sized bags (4 °C, 10 days) were monitored. All washing procedures applied significantly reduced the SL contents and bitterness in fresh-cut chicory. Warm water washing was most effective, reducing the total SL levels by 60.9-64.5%. Sensory and color attributes were also retained best by warm water washing, suggesting such treatments to be suitable measures to improve the quality and reduce the bitterness of fresh-cut chicory. SL profiles changed substantially in all samples during storage, revealing lactucopicrin to be the major SL directly after processing, whereas 11(S),13-dihydrolactuin prevailed at the end of storage.

  7. Tiller number is altered in the ascorbic acid-deficient rice suppressed for L-galactono-1,4-lactone dehydrogenase.

    PubMed

    Liu, Yonghai; Yu, Le; Tong, Jianhua; Ding, Junhui; Wang, Ruozhong; Lu, Yusheng; Xiao, Langtao

    2013-03-01

    The tiller of rice (Oryza sativa L.), which determines the panicle number per plant, is an important agronomic trait for grain production. Ascorbic acid (Asc) is a major plant antioxidant that serves many functions in plants. L-Galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3) is an enzyme that catalyzes the last step of Asc biosynthesis in plants. Here we show that the GLDH-suppressed transgenic rices, GI-1 and GI-2, which have constitutively low (between 30% and 50%) leaf Asc content compared with the wild-type plants, exhibit a significantly reduced tiller number. Moreover, lower growth rate and plant height were observed in the Asc-deficient plants relative to the trait values of the wild-type plants at different tillering stages. Further examination showed that the deficiency of Asc resulted in a higher lipid peroxidation, a loss of chlorophyll, a loss of carotenoids, and a lower rate of CO(2) assimilation. In addition, the level of abscisic acid was higher in GI-1 plants, while the level of jasmonic acid was higher in GI-1 and GI-2 plants at different tillering stages. The results we presented here indicated that Asc deficiency was likely responsible for the promotion of premature senescence, which was accompanied by a marked decrease in photosynthesis. These observations support the conclusion that the deficiency of Asc alters the tiller number in the GLDH-suppressed transgenics through promoting premature senescence and changing phytohormones related to senescence.

  8. TraI, a LuxI homologue, is responsible for production of conjugation factor, the Ti plasmid N-acylhomoserine lactone autoinducer.

    PubMed

    Hwang, I; Li, P L; Zhang, L; Piper, K R; Cook, D M; Tate, M E; Farrand, S K

    1994-05-24

    Conjugal transfer of the nopaline-type Agrobacterium Ti plasmid pTiC58 is regulated by a transcriptional activator, TraR, and a diffusible signal molecule, conjugation factor (CF). CF is a member of a family of substituted homoserine lactones (HSLs) that act as coinducers for regulating gene expression in diverse Gram-negative bacteria by a mechanism called autoinduction. In Vibrio fischeri HSL production is conferred by the luxI gene. Homologues of this gene are responsible for HSL production by other Gram-negative bacteria. A gene that we call traI, conferring production of material with CF activity, was localized to a 1-kb region at the upstream end of tra3 of pTiC58. Spectroscopy showed that the activity was authentic CF. Sequence analysis showed that traI could encode a protein of 211 amino acids, TraI, that is related to the proteins responsible for HSL production by other bacteria. A second, partial open reading frame immediately downstream of traI could encode a protein related to TrbB of plasmid RP4, which is required for conjugal transfer. Transcription of traI and of the downstream tra3 genes requires TraR and CF and initiates from the traI promoter. The results show that traI is responsible for CF production, that it is the first gene of the tra3 operon, and that expression of this operon is regulated by autoinduction.

  9. Quorum sensing by N-acylhomoserine lactones is not required for Aeromonas hydrophila during growth with organic particles in lake water microcosms.

    PubMed

    Styp von Rekowski, Katharina; Hempel, Melanie; Philipp, Bodo

    2008-05-01

    It was investigated whether quorum sensing (QS) mediated by N-acylhomoserine lactones (AHLs) was important for heterotrophic bacteria from the littoral zone of the oligotrophic Lake Constance for growth with organic particles. More than 900 colonies from lake water microcosms with artificial organic aggregates consisting of autoclaved unicellular algae embedded in agarose beads were screened for AHL-production. AHL-producing bacteria of the genus Aeromonas enriched in the microcosms but AHLs could not be detected in any microcosm. To test for a potential function of AHL-mediated QS, growth experiments with the wild type and an AHL-deficient mutant of Aeromonas hydrophila in lake water microcosms were performed. Growth of both strains did not differ in single cultures and showed no mutual influence in co-cultures. In co-cultures with a competitor bacterium belonging to the Cytophaga-Flavobacterium group, growth of both A. hydrophila strains was reduced while growth of the competitor bacterium was not affected. Exogenous AHL-addition did not influence growth of the Aeromonas strains in any microcosm experiment. These results showed that AHL-mediated QS was not required for A. hydrophila during colonization and degradation of organic particles in lake water microcosms, suggesting that cell-cell signalling of heterotrophic bacteria in oligotrophic waters relies on novel signal molecules.

  10. Atomic force microscopy reveals a morphological differentiation of chromobacterium violaceum cells associated with biofilm development and directed by N-hexanoyl-L-homoserine lactone.

    PubMed

    Kamaeva, Anara A; Vasilchenko, Alexey S; Deryabin, Dmitry G

    2014-01-01

    Chromobacterium violaceum abounds in soil and water ecosystems in tropical and subtropical regions and occasionally causes severe and often fatal human and animal infections. The quorum sensing (QS) system and biofilm formation are essential for C. violaceum's adaptability and pathogenicity, however, their interrelation is still unknown. C. violaceum's cell and biofilm morphology were examined by atomic force microscopy (AFM) in comparison with growth rates, QS-dependent violacein biosynthesis and biofilm biomass quantification. To evaluate QS regulation of these processes, the wild-type strain C. violaceum ATCC 31532 and its mini-Tn5 mutant C. violaceum NCTC 13274, cultivated with and without the QS autoinducer N-hexanoyl-L-homoserine lactone (C6-HSL), were used. We report for the first time the unusual morphological differentiation of C. violaceum cells, associated with biofilm development and directed by the QS autoinducer. AFM revealed numerous invaginations of the external cytoplasmic membrane of wild-type cells, which were repressed in the mutant strain and restored by exogenous C6-HSL. With increasing bacterial growth, polymer matrix extrusions formed in place of invaginations, whereas mutant cells were covered with a diffusely distributed extracellular substance. Thus, quorum sensing in C. violaceum involves a morphological differentiation that organises biofilm formation and leads to a highly differentiated matrix structure.

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

    PubMed

    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

    PubMed Central

    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. Identification of the Quorum-Sensing Target DNA Sequence and N-Acyl Homoserine Lactone Responsiveness of the Brucella abortus virB promoter▿

    PubMed Central

    Arocena, Gastón M.; Sieira, Rodrigo; Comerci, Diego J.; Ugalde, Rodolfo A.

    2010-01-01

    VjbR is a LuxR-type quorum-sensing (QS) regulator that plays an essential role in the virulence of the intracellular facultative pathogen Brucella, the causative agent of brucellosis. It was previously described that VjbR regulates a diverse group of genes, including the virB operon. The latter codes for a type IV secretion system (T4SS) that is central for the pathogenesis of Brucella. Although the regulatory role of VjbR on the virB promoter (PvirB) was extensively studied by different groups, the VjbR-binding site had not been identified so far. Here, we identified the target DNA sequence of VjbR in PvirB by DNase I footprinting analyses. Surprisingly, we observed that VjbR specifically recognizes a sequence that is identical to a half-binding site of the QS-related regulator MrtR of Mesorhizobium tianshanense. As shown by DNase I footprinting and electrophoretic mobility shift assays, generation of a palindromic MrtR-like-binding site in PvirB increased both the affinity and the stability of the VjbR-DNA complex, which confirmed that the QS regulator of Brucella is highly related to that of M. tianshanense. The addition of N-dodecanoyl homoserine lactone dissociated VjbR from the promoter, which confirmed previous reports that indicated a negative effect of this signal on the VjbR-mediated activation of PvirB. Our results provide new molecular evidence for the structure of the virB promoter and reveal unusual features of the QS target DNA sequence of the main regulator of virulence in Brucella. PMID:20400542

  14. Santamarin, a sesquiterpene lactone isolated from Saussurea lappa, represses LPS-induced inflammatory responses via expression of heme oxygenase-1 in murine macrophage cells.

    PubMed

    Choi, Hyun-Gyu; Lee, Dong-Sung; Li, Bin; Choi, Yeon Ho; Lee, Seung-Ho; Kim, Youn-Chul

    2012-07-01

    Saussurea lappa C.B. Clarke (Compositae) is indigenous to India and Pakistan. The dried root of S. lappa has been traditionally used for alleviating pain in abdominal distention and tenesmus, indigestion with anorexia, dysentery, nausea, and vomiting. Santamarin is a sesquiterpene lactone isolated from S. lappa. In the present study, santamarin inhibited inducible nitric oxide synthase (iNOS) protein, reduced iNOS-derived nitric oxide (NO), suppressed COX-2 protein and reduced COX-derived PGE(2) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and murine peritoneal macrophages. Similarly, santamarin reduced tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) production. In addition, santamarin suppressed the phosphorylation and degradation of IκB-α as well as the nuclear translocation of p65 in response to LPS in RAW264.7 cells. Furthermore, santamarin induced heme oxygenase (HO)-1 expression mRNA and protein level that plays a cytoprotective role against inflammation. The induction of HO-1 is primarily regulated at the transcriptional level, and its induction by various agents is mediated by the nuclear transcription factor E2-related factor 2 (Nrf2), master regulator of antioxidant responses. Unbound Nrf2 translocates into the nucleus and binds to the antioxidant response element (ARE) in the upstream promoter region of many antioxidative genes, where it initiates their transcription. The effects of santamarin on LPS-induced NO, PGE(2), TNF-α, and IL-1β production were partially reversed by the HO-1 inhibitor, tin protoporphyrin (SnPP). Therefore, our data suggest that the anti-inflammatory effect of santamarin in macrophages may be exerted through a novel mechanism that involves HO-1 expression.

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

    PubMed

    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.

  16. The Pseudomonas aeruginosa quorum-sensing signal N-(3-oxododecanoyl) homoserine lactone can accelerate cutaneous wound healing through myofibroblast differentiation in rats.

    PubMed

    Nakagami, Gojiro; Minematsu, Takeo; Asada, Mayumi; Nagase, Takashi; Akase, Tomoko; Huang, Lijuan; Morohoshi, Tomohiro; Ikeda, Tsukasa; Ohta, Yasunori; Sanada, Hiromi

    2011-07-01

    Quorum sensing is a cell density-dependent gene regulation system in bacteria. N-(3-oxododecanoyl) homoserine lactone (3-oxo-C12-HSL) is used in the las quorum-sensing system in Pseudomonas aeruginosa, which is an opportunistic pathogen that causes many human diseases. Although many studies have investigated the sole effects of quorum sensing on several types of mammalian cells, including lung cells, little is known about the effects of quorum sensing on the cells associated with wound healing. To better understand the mechanism of bacterial wound infection, we investigated the effects of 3-oxo-C12-HSL on cells using a rat full-thickness wound-healing model. We found that the wound contraction was significantly increased at 24 h after the administration of 3-oxo-C12-HSL to the surface of granulation tissue. Differentiation of fibroblasts to myofibroblasts was induced in the in vivo wound-healing model and was confirmed in vitro using the rat fibroblastic cell line Rat-1. Cyclooxygenase (Cox)-2 expression was also induced in Rat-1 cells by 3-oxo-C12-HSL. This finding suggested that Cox-2 upregulation may be related to the inflammatory findings in the histological examinations, in which infiltrating polymorphonuclear neutrophils were observed at the wound site. Taken together, these results imply that mammals have a potential defense system against invading pathogens by responding to the presence of 3-oxo-C12-HSL and inducing the differentiation of fibroblasts to myofibroblasts as well as inflammation for accelerating wound healing.

  17. Paraoxonase 2 Serves a Proapopotic Function in Mouse and Human Cells in Response to the Pseudomonas aeruginosa Quorum-sensing Molecule N-(3-Oxododecanoyl)-homoserine Lactone*

    PubMed Central

    Schwarzer, Christian; Fu, Zhu; Morita, Takeshi; Whitt, Aaron G.; Neely, Aaron M.; Li, Chi; Machen, Terry E.

    2015-01-01

    Pseudomonas aeruginosa use quorum-sensing molecules, including N-(3-oxododecanoyl)-homoserine lactone (C12), for intercellular communication. C12 activated apoptosis in mouse embryo fibroblasts (MEF) from both wild type (WT) and Bax/Bak double knock-out mice (WT MEF and DKO MEF that were responsive to C12, DKOR MEF): nuclei fragmented; mitochondrial membrane potential (Δψmito) depolarized; Ca2+ was released from the endoplasmic reticulum (ER), increasing cytosolic [Ca2+] (Cacyto); and caspase 3/7 was activated. DKOR MEF had been isolated from a nonclonal pool of DKO MEF that were non-responsive to C12 (DKONR MEF). RNAseq analysis, quantitative PCR, and Western blots showed that WT and DKOR MEF both expressed genes associated with cancer, including paraoxonase 2 (PON2), whereas DKONR MEF expressed little PON2. Adenovirus-mediated expression of human PON2 in DKONR MEF rendered them responsive to C12: Δψmito depolarized, Cacyto increased, and caspase 3/7 activated. Human embryonic kidney 293T (HEK293T) cells expressed low levels of endogenous PON2, and these cells were also less responsive to C12. Overexpression of PON2, but not PON2-H114Q (no lactonase activity) in HEK293T cells caused them to become sensitive to C12. Because [C12] may reach high levels in biofilms in lungs of cystic fibrosis (CF) patients, PON2 lactonase activity may control Δψmito, Ca2+ release from the ER, and apoptosis in CF airway epithelia. Coupled with previous data, these results also indicate that PON2 uses its lactonase activity to prevent Bax- and Bak-dependent apoptosis in response to common proapoptotic drugs like doxorubicin and staurosporine, but activates Bax- and Bak-independent apoptosis in response to C12. PMID:25627690

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

    PubMed

    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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27443220

  20. Diversity of culturable bacterial communities in the intestinal tracts of goldfish (Carassius auratus) and their ability to produce N-acyl homoserine lactone.

    PubMed

    Sugita, Haruo; Kitao, Shun; Narisawa, Satoshi; Minamishima, Ryosuke; Itoi, Shiro

    2017-01-26

    Intestinal bacteria isolated from goldfish (Carassius auratus) were identified based on 16 ribosomal RNA (rRNA) gene sequences and screened for their ability to produce N-acyl homoserine lactone (AHL), an autoinducer of the quorum sensing (QS) system. The 230 aerobes/facultative anaerobes that were isolated comprised members of the genera Aeromonas (184 isolates), Citrobacter (11), Enterobacter (2), Shewanella (28), Vagococcus (1), and Vibrio (4). Among these genera, the two most abundant species were Aeromonas veronii (163 isolates) and Shewanella xiamenensis (27). In addition, 142 obligate anaerobes consisting of Cetobacterium somerae (139 isolates), Clostridium frigidicarnis (2), and Cetobacterium sp. (1) were also isolated. One hundred seventy isolates (74.2%) belonging to the genera Aeromonas, Citrobacter, Enterobacter, Shewanella, and Vibrio produced AHL, while 155 (67.7%) and 91 (39.7%) isolates possessed the luxR and luxI gene homologs, respectively. None of the obligate anaerobes produced AHL or possessed luxRI homologs. Total viable counts ranged from 1.2 × 10(7) to 2.2 × 10(9) CFU/g, which were accounted for 0.8 to 15.2% of direct counts. Aeromonas veronii, S. xiamenensis, and C. somerae were detected from five goldfish at densities ranging from 4.0 × 10(6) to 1.7 × 10(9) CFU/g, indicating that these bacteria are dominant components of the culturable gut flora in goldfish. In addition, members of the genera Aeromonas and Shewanella appeared to communicate with each other by using the QS system to some extent when the concentration of AHL reaches a certain threshold. It is therefore suggested that bacteria with the ability to disrupt AHL secretion in intestinal environments are potential candidates for probionts for preventing opportunistic infections in freshwater fish such as goldfish.

  1. Pseudomonas aeruginosa N-3-oxo-dodecanoyl-homoserine Lactone Elicits Changes in Cell Volume, Morphology, and AQP9 Characteristics in Macrophages

    PubMed Central

    Holm, Angelika; Magnusson, Karl-Eric; Vikström, Elena

    2016-01-01

    Quorum sensing (QS) communication allows Pseudomonas aeruginosa to collectively control its population density and the production of biofilms and virulence factors. QS signal molecules, like N-3-oxo-dodecanoyl-L-homoserine lactone (3O-C12-HSL), can also affect the behavior of host cells, e.g., by modulating the chemotaxis, migration, and phagocytosis of human leukocytes. Moreover, host water homeostasis and water channels aquaporins (AQP) are critical for cell morphology and functions as AQP interact indirectly with the cell cytoskeleton and signaling cascades. Here, we investigated how P. aeruginosa 3O-C12-HSL affects cell morphology, area, volume and AQP9 expression and distribution in human primary macrophages, using quantitative PCR, immunoblotting, two- and three-dimensional live imaging, confocal and nanoscale imaging. Thus, 3O-C12-HSL enhanced cell volume and area and induced cell shape and protrusion fluctuations in macrophages, processes tentatively driven by fluxes of water across cell membrane through AQP9, the predominant AQP in macrophages. Moreover, 3O-C12-HSL upregulated the expression of AQP9 at both the protein and mRNA levels. This was accompanied with enhanced whole cell AQP9 fluorescent intensity and redistribution of AQP9 to the leading and trailing regions, in parallel with increased cell area in the macrophages. Finally, nanoscopy imaging provided details on AQP9 dynamics and architecture within the lamellipodial area of 3O-C12-HSL-stimulated cells. We suggest that these novel events in the interaction between P. aeruginosa and macrophage may have an impact on the effectiveness of innate immune cells to fight bacteria, and thereby resolve the early stages of infections and inflammations. PMID:27047801

  2. LuxR- and Acyl-Homoserine-Lactone-Controlled Non-lux Genes Define a Quorum-Sensing Regulon in Vibrio fischeri

    PubMed Central

    Callahan, Sean M.; Dunlap, Paul V.

    2000-01-01

    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. PMID:10781550

  3. A sesquiterpene lactone antrocin from Antrodia camphorata negatively modulates JAK2/STAT3 signaling via microRNA let-7c and induces apoptosis in lung cancer cells.

    PubMed

    Yeh, Chi-Tai; Huang, Wen-Chien; Rao, Yerra Koteswara; Ye, Min; Lee, Wei-Hwa; Wang, Liang-Shun; Tzeng, David T W; Wu, Chih-Hsiung; Shieh, Yi-Shing; Huang, Chi-Ying F; Chen, Yu-Jen; Hsiao, Michael; Wu, Alexander T H; Yang, Zhen; Tzeng, Yew-Min

    2013-12-01

    Lung cancer is the leading cause of cancer deaths worldwide and current therapies fail to treat this disease in majority of cases. Antrodia camphorata is a medicinal mushroom being widely used as food dietary supplement for cancer prevention. The sesquiterpene lactone antrocin is the most potent among >100 secondary metabolites isolated from A. camphorata. However, the molecular mechanisms of antrocin-mediated anticancer effects remain unclear. In this study, we found that antrocin inhibited cell proliferation in two non-small-cell lung cancer cells, namely H441 (wild-type epidermal growth factor receptor, IC50 = 0.75 μM) and H1975 (gefitnib-resistant mutant T790M, IC50 = 0.83 μM). Antrocin dose dependently suppressed colony formation and induced apoptosis as evidenced by activated caspase-3 and increased Bax/Bcl2 ratio. Gene profiling studies indicated that antrocin downregulated Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway. We further demonstrated that antrocin suppressed both constitutively activated and interleukin 6-induced STAT3 phosphorylation and its subsequent nuclear translocation. Such inhibition is found to be achieved through the suppression of JAK2 and interaction between STAT3 and extracellular signal-regulated kinase. Additionally, antrocin increased microRNA let-7c expression and suppressed STAT signaling. The combination of antrocin and JAK2/STAT3 gene silencing significantly increased apoptosis in H441 cells. Such dual interruption of JAK2 and STAT3 pathways also induced downregulation of antiapoptotic protein mcl-1 and increased caspase-3 expression. In vivo intraperitoneal administration of antrocin significantly suppressed the growth of lung cancer tumor xenografts. Our results indicate that antrocin may be a potential therapeutic agent for human lung cancer cells through constitutive inhibition of JAK2/STAT3 pathway.

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

    SciTech Connect

    Paes, Camila

    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 process.

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

    PubMed

    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.

  6. Identification of Unanticipated and Novel N-Acyl L-Homoserine Lactones (AHLs) Using a Sensitive Non-Targeted LC-MS/MS Method

    PubMed Central

    Patel, Nishaben M.; Moore, Joseph D.; Blackwell, Helen E.; Amador-Noguez, Daniel

    2016-01-01

    N-acyl L-homoserine lactones (AHLs) constitute a predominant class of quorum-sensing signaling molecules used by Gram-negative bacteria. Here, we report a sensitive and non-targeted HPLC-MS/MS method based on parallel reaction monitoring (PRM) to identify and quantitate known, unanticipated, and novel AHLs in microbial samples. Using a hybrid quadrupole-high resolution mass analyzer, this method integrates MS scans and all-ion fragmentation MS/MS scans to allow simultaneous detection of AHL parent-ion masses and generation of full mass spectra at high resolution and high mass accuracy in a single chromatographic run. We applied this method to screen for AHL production in a variety of Gram-negative bacteria (i.e. B. cepacia, E. tarda, E. carotovora, E. herbicola, P. stewartii, P. aeruginosa, P. aureofaciens, and R. sphaeroides) and discovered that nearly all of them produce a larger set of AHLs than previously reported. Furthermore, we identified production of an uncommon AHL (i.e. 3-oxo-C7-HL) in E. carotovora and P. stewartii, whose production has only been previously observed within the genera Serratia and Yersinia. Finally, we used our method to quantitate AHL degradation in B. cepacia, E. carotovora, E. herbicola, P. stewartii, P. aeruginosa, P. aureofaciens, the non-AHL producer E. coli, and the Gram-positive bacterium B. subtilis. We found that AHL degradation ability varies widely across these microbes, of which B. subtilis and E. carotovora are the best degraders, and observed that there is a general trend for AHLs containing long acyl chains (≥10 carbons) to be degraded at faster rates than AHLs with short acyl chains (≤6 carbons). PMID:27706219

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

    PubMed Central

    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 23270T 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. ferrooxidansT, 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. ferrooxidansT 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 23270T 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. PMID:27683573

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

    PubMed

    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.

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

    PubMed

    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.

  10. Macrocyclic Lactones Differ in Interaction with Recombinant P-Glycoprotein 9 of the Parasitic Nematode Cylicocylus elongatus and Ketoconazole in a Yeast Growth Assay

    PubMed Central

    Kaschny, Maximiliane; Demeler, Janina; Janssen, I. Jana I.; Kuzmina, Tetiana A.; Besognet, Bruno; Kanellos, Theo; Kerboeuf, Dominique; von Samson-Himmelstjerna, Georg; Krücken, Jürgen

    2015-01-01

    Macrocyclic lactones (MLs) are widely used parasiticides against nematodes and arthropods, but resistance is frequently observed in parasitic nematodes of horses and livestock. Reports claiming resistance or decreased susceptibility in human nematodes are increasing. Since no target site directed ML resistance mechanisms have been identified, non-specific mechanisms were frequently implicated in ML resistance, including P-glycoproteins (Pgps, designated ABCB1 in vertebrates). Nematode genomes encode many different Pgps (e.g. 10 in the sheep parasite Haemonchus contortus). ML transport was shown for mammalian Pgps, Pgps on nematode egg shells, and very recently for Pgp-2 of H. contortus. Here, Pgp-9 from the equine parasite Cylicocyclus elongatus (Cyathostominae) was expressed in a Saccharomyces cerevisiae strain lacking seven endogenous efflux transporters. Pgp was detected on these yeasts by flow cytometry and chemiluminescence using the monoclonal antibody UIC2, which is specific for the active Pgp conformation. In a growth assay, Pgp-9 increased resistance to the fungicides ketoconazole, actinomycin D, valinomycin and daunorubicin, but not to the anthelmintic fungicide thiabendazole. Since no fungicidal activity has been described for MLs, their interaction with Pgp-9 was investigated in an assay involving two drugs: Yeasts were incubated with the highest ketoconazole concentration not affecting growth plus increasing concentrations of MLs to determine competition between or modulation of transport of both drugs. Already equimolar concentrations of ivermectin and eprinomectin inhibited growth, and at fourfold higher ML concentrations growth was virtually abolished. Selamectin and doramectin did not increase susceptibility to ketoconazole at all, although doramectin has been shown previously to strongly interact with human and canine Pgp. An intermediate interaction was observed for moxidectin. This was substantiated by increased binding of UIC2 antibodies in the

  11. Macrocyclic lactones differ in interaction with recombinant P-glycoprotein 9 of the parasitic nematode Cylicocylus elongatus and ketoconazole in a yeast growth assay.

    PubMed

    Kaschny, Maximiliane; Demeler, Janina; Janssen, I Jana I; Kuzmina, Tetiana A; Besognet, Bruno; Kanellos, Theo; Kerboeuf, Dominique; von Samson-Himmelstjerna, Georg; Krücken, Jürgen

    2015-04-01

    Macrocyclic lactones (MLs) are widely used parasiticides against nematodes and arthropods, but resistance is frequently observed in parasitic nematodes of horses and livestock. Reports claiming resistance or decreased susceptibility in human nematodes are increasing. Since no target site directed ML resistance mechanisms have been identified, non-specific mechanisms were frequently implicated in ML resistance, including P-glycoproteins (Pgps, designated ABCB1 in vertebrates). Nematode genomes encode many different Pgps (e.g. 10 in the sheep parasite Haemonchus contortus). ML transport was shown for mammalian Pgps, Pgps on nematode egg shells, and very recently for Pgp-2 of H. contortus. Here, Pgp-9 from the equine parasite Cylicocyclus elongatus (Cyathostominae) was expressed in a Saccharomyces cerevisiae strain lacking seven endogenous efflux transporters. Pgp was detected on these yeasts by flow cytometry and chemiluminescence using the monoclonal antibody UIC2, which is specific for the active Pgp conformation. In a growth assay, Pgp-9 increased resistance to the fungicides ketoconazole, actinomycin D, valinomycin and daunorubicin, but not to the anthelmintic fungicide thiabendazole. Since no fungicidal activity has been described for MLs, their interaction with Pgp-9 was investigated in an assay involving two drugs: Yeasts were incubated with the highest ketoconazole concentration not affecting growth plus increasing concentrations of MLs to determine competition between or modulation of transport of both drugs. Already equimolar concentrations of ivermectin and eprinomectin inhibited growth, and at fourfold higher ML concentrations growth was virtually abolished. Selamectin and doramectin did not increase susceptibility to ketoconazole at all, although doramectin has been shown previously to strongly interact with human and canine Pgp. An intermediate interaction was observed for moxidectin. This was substantiated by increased binding of UIC2 antibodies in the

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

    PubMed

    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.

  13. Gene expression analysis of ABC transporters in a resistant Cooperia oncophora isolate following in vivo and in vitro exposure to macrocyclic lactones.

    PubMed

    De Graef, J; Demeler, J; Skuce, P; Mitreva, M; Von Samson-Himmelstjerna, G; Vercruysse, J; Claerebout, E; Geldhof, P

    2013-04-01

    Members of the ATP-binding cassette (ABC) transporter family (P-glycoproteins, Half-transporters and Multidrug Resistant Proteins) potentially play a role in the development of anthelmintic resistance. The aim of this study was to investigate the possible involvement of ABC transporters in anthelmintic resistance in the bovine parasite, Cooperia oncophora. Partial sequences of 15 members of the ABC transporter protein family were identified, by mining a transcriptome dataset combined with a degenerate PCR approach. Reverse transcriptase PCR showed that most of the ABC transporters identified were constitutively transcribed throughout the life cycle of C. oncophora. Constitutive differences in gene transcript levels between a susceptible and resistant isolate were only observed for Con-haf-9 and Con-mrp-1 in eggs of the resistant isolate, while no differences were observed in L3 or the adult life stage. Analysis of resistant adult worms, collected from calves 14 days after treatment with either ivermectin or moxidectin, showed a significant 3- to 5-fold increase in the transcript levels of Con-pgp-11 compared to non-exposed worms. Interestingly, a 4-fold transcriptional up-regulation of Con-pgp-11 was also observed in L3 of the resistant isolate, after in vitro exposure to different concentrations of ivermectin, whereas this effect was not observed in exposed L3 of the susceptible isolate. The results suggest that the worms of this particular resistant isolate have acquired the ability to up-regulate Con-pgp-11 upon exposure to macrocyclic lactones. Further work is needed to understand the genetic basis underpinning this process and the functional role of PGP-11.

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

    PubMed

    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.

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

    PubMed Central

    Gan, Han Ming; Dailey, Lucas K.; Halliday, Nigel; Williams, Paul; Hudson, André O.

    2016-01-01

    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. PMID:27635318

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

    PubMed

    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.

  17. Transient infrared absorption of t-CH3C(O)OO, c-CH3C(O)OO, and α-lactone recorded in gaseous reactions of CH3CO and O2

    NASA Astrophysics Data System (ADS)

    Chen, Sun-Yang; Lee, Yuan-Pern

    2010-03-01

    A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the transient species produced in gaseous reactions of CH3CO and O2; IR absorption spectra of CH3C(O)OO and α-lactone were observed. Absorption bands with origins at 1851±1, 1372±2, 1169±6, and 1102±3 cm-1 are attributed to t-CH3C(O)OO, and those at 1862±3, 1142±4, and 1078±6 cm-1 are assigned to c-CH3C(O)OO. A weak band near 1960 cm-1 is assigned to α-lactone, cyc-CH2C(O)O, a coproduct of OH. These observed rotational contours agree satisfactorily with simulated bands based on predicted rotational parameters and dipole derivatives, and observed vibrational wavenumbers agree with harmonic vibrational wavenumbers predicted with B3LYP/aug-cc-pVDZ density-functional theory. The observed relative intensities indicate that t-CH3C(O)OO is more stable than c-CH3C(O)OO by 3±2 kJ mol-1. Based on these observations, the branching ratio for the OH+α-lactone channel of the CH3CO+O2 reaction is estimated to be 0.04±0.01 under 100 Torr of O2 at 298 K. A simple kinetic model is employed to account for the decay of CH3C(O)OO.

  18. Quorum sensing in Aeromonas hydrophila and Aeromonas salmonicida: identification of the LuxRI homologs AhyRI and AsaRI and their cognate N-acylhomoserine lactone signal molecules.

    PubMed Central

    Swift, S; Karlyshev, A V; Fish, L; Durant, E L; Winson, M K; Chhabra, S R; Williams, P; Macintyre, S; Stewart, G S

    1997-01-01

    Spent culture supernatants from both Aeromonas hydrophila and Aeromonas salmonicida activate a range of biosensors responsive to N-acylhomoserine lactones (AHLs). The genes for a quorum sensing signal generator and a response regulator were cloned from each Aeromonas species and termed ahyRI and asaRI, respectively. Protein sequence homology analysis places the gene products within the growing family of LuxRI homologs. ahyR and asaR are transcribed divergently from ahyI and asaI, respectively, and in both Aeromonas species, the genes downstream have been identified by DNA sequence and PCR analysis. Downstream of both ahyI and asaI is a gene with close homology to iciA, an inhibitor of chromosome replication in Escherichia coli, a finding which implies that in Aeromonas, cell division may be linked to quorum sensing. The major signal molecule synthesized via both AhyI and AsaI was purified from spent culture supernatants and identified as N-(butanoyl)-L-homoserine lactone (BHL) by thin-layer chromatography, high-pressure liquid chromatography analysis, and mass spectrometry. In addition, a second, minor AHL, N-hexanoyl-L-homoserine lactone, was identified. Transcriptional reporter studies with ahyI::luxCDABE fusions indicate that AhyR and BHL are both required for ahyI transcription. For A. salmonicida, although the addition of exogenous BHL gives only a small stimulation of the production of serine protease with comparison to the control culture, the incorporation of a longer-chain AHL, N-(3-oxodecanoyl)-L-homoserine lactone, reduced the final level (by approximately 50%) and delayed the appearance (from an A650 of 0.9 in the control to an A650 of 1.2 in the test) of protease in the culture supernatant. These data add A. hydrophila and A. salmonicida to the growing family of gram-negative bacteria now known to control gene expression through quorum sensing. PMID:9286976

  19. Decreased overall basicity of a series of new N,N'-bis(carboxymethyl) macrocylcic ether-bis(lactone) ligands derived from EDTA and the ring size effect on the stability constants of their lanthanide complexes

    SciTech Connect

    Chang, C.A.; Chang, P.H.L.; Qin, S.Y.

    1988-03-09

    In order to examine the effects of positions of the nitrogen donor atoms and the relative coordination sites of the two carboxylate groups on lanthanide complexation in the study of the characteristics of both open-chain and macrocyclic ligands for the preparation of novel metal-ion selective reagents, a series of N, N'-bis(carboxymethyl)macrocyclic ether-bis(lactone)ligands derived from ethylenediaminetetraacetic acid have been prepared and characterized. The ligand protonation constants and the lanthanide complex formation constants have been determined and are reported here. 14 references, 2 figures, 2 tables.

  20. RND type efflux pump system MexAB-OprM of pseudomonas aeruginosa selects bacterial languages, 3-oxo-acyl-homoserine lactones, for cell-to-cell communication

    PubMed Central

    2012-01-01

    Background Bacteria release a wide variety of small molecules including cell-to-cell signaling compounds. Gram-negative bacteria use a variety of self-produced autoinducers such as acylated homoserine lactones (acyl-HSLs) as signal compounds for quorum sensing (QS) within and between bacterial species. QS plays a significant role in the pathogenesis of infectious diseases and in beneficial symbiosis by responding to acyl-HSLs in Pseudomonas aeruginosa. It is considered that the selection of bacterial languages is necessary to regulate gene expression and thus it leads to the regulation of virulence and provides a growth advantage in several environments. In this study, we hypothesized that RND-type efflux pump system MexAB-OprM of P. aeruginosa might function in the selection of acyl-HSLs, and we provide evidence to support this hypothesis. Results Loss of MexAB-OprM due to deletion of mexB caused increases in QS responses, as shown by the expression of gfp located downstream of the lasB promoter and LasB elastase activity, which is regulated by a LasR-3-oxo-C12-HSL complex. Either complementation with a plasmid containing wild-type mexB or the addition of a LasR-specific inhibitor, patulin, repressed these high responses to 3-oxo-acyl-HSLs. Furthermore, it was shown that the acyl-HSLs-dependent response of P. aeruginosa was affected by the inhibition of MexB transport activity and the mexB mutant. The P. aeruginosa MexAB-OprM deletion mutant showed a strong QS response to 3-oxo-C10-HSL produced by Vibrio anguillarum in a bacterial cross-talk experiment. Conclusion This work demonstrated that MexAB-OprM does not control the binding of LasR to 3-oxo-Cn-HSLs but rather accessibility of non-cognate acyl-HSLs to LasR in P. aeruginosa. MexAB-OprM not only influences multidrug resistance, but also selects acyl-HSLs and regulates QS in P. aeruginosa. The results demonstrate a new QS regulation mechanism via the efflux system MexAB-OprM in P. aeruginosa. PMID:22574700