Articoli di riviste: "Lactones"

1

Faizullina, Lily Kh, Yulia A. Khalilova, Artur R. Tagirov, Yulia S. Galimova, Farid A. Valeev, Alyona S. Ryabova e Naila F. Galimzyanova. "Evaluation of fungicidal, bactericidal and anti-tumor activities of lactones of medium and large sizes of cycles obtained from levoglucosenone". Butlerov Communications 59, n. 9 (30 settembre 2019): 100–105. http://dx.doi.org/10.37952/roi-jbc-01/19-59-9-100.

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Medium and large lactones attract the attention of chemists by the uniqueness of their structure, versatile biological activity and limited availability. Among the secondary metabolites of this group, β-lactones are more common, then γ- and δ-lactones, classical and non-classical macrolides, polyene antibiotics, spiro-macrolides and macrolactones. On the basis of many lactones, important preparations of the most diverse pharmacological action have been obtained. Earlier, we proposed a 3-stage scheme for the synthesis of chiral lactones of medium and large size based on levoglucosenone. The lactones obtained according to this scheme contain the carbohydrate residue annelated at the ,γ -positions relative to the hydroxy group. To study the structure-activity relationship, it is necessary to establish the biological role of this carbohydrate residue in reference lactones. For this purpose, a number of lactones were obtained on the basis of levoglucosenone and their in vitro bioscreening of antifungal, antimicrobial, and antitumor activity was performed. It was found that the methyl substituent in the ω-position in the lactone and the benzene ring annulated with the lactone cycle exhibit a slight fungistatic activity towards the fungi: Bipolaris sorokiniana, Fusarium oxysporum, Rhizoctonia solani. Macrocyclic lactone and lactone annelated benzene ring showed weak cytotoxic properties against cells of LOX IMVI (melanoma) and A498, UO-31 (kidney cancer).

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Schaefer, Amy L., Terumi A. Taylor, J. Thomas Beatty e E. P. Greenberg. "Long-Chain Acyl-Homoserine Lactone Quorum-Sensing Regulation of Rhodobacter capsulatus Gene Transfer Agent Production". Journal of Bacteriology 184, n. 23 (1 dicembre 2002): 6515–21. http://dx.doi.org/10.1128/jb.184.23.6515-6521.2002.

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ABSTRACT Many proteobacteria use acyl-homoserine lactones as quorum-sensing signals. Traditionally, biological detection systems have been used to identify bacteria that produce acyl-homoserine lactones, although the specificities of these detection systems can limit discovery. We used a sensitive approach that did not require a bioassay to detect production of long-acyl-chain homoserine lactone production by Rhodobacter capsulatus and Paracoccus denitrificans. These long-chain acyl-homoserine lactones are not readily detected by standard bioassays. The most abundant acyl-homoserine lactone was N-hexadecanoyl-homoserine lactone. The long-chain acyl-homoserine lactones were concentrated in cells but were also found in the culture fluid. An R. capsulatus gene responsible for long-chain acyl-homoserine lactone synthesis was identified. A mutation in this gene, which we named gtaI, resulted in decreased production of the R. capsulatus gene transfer agent, and gene transfer agent production was restored by exogenous addition of N-hexadecanoyl-homoserine lactone. Thus, long-chain acyl-homoserine lactones serve as quorum-sensing signals to enhance genetic exchange in R. capsulatus.

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Ulrich, Ricky L. "Quorum Quenching: Enzymatic Disruption of N-Acylhomoserine Lactone-Mediated Bacterial Communication in Burkholderia thailandensis". Applied and Environmental Microbiology 70, n. 10 (ottobre 2004): 6173–80. http://dx.doi.org/10.1128/aem.70.10.6173-6180.2004.

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ABSTRACT 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.

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4

Cambie, Richard C., Lorna H. Mitchell e Peter S. Rutledge. "Acid-Promoted Fries Rearrangements of Benzannulated Lactones". Australian Journal of Chemistry 51, n. 12 (1998): 1167. http://dx.doi.org/10.1071/c98023.

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The scope of acid-promoted Fries rearrangements of benzannulated lactones has been examined. The reaction is applicable to seven-membered lactones possessing a sufficiently activated aromatic ring but not to six-membered lactones, and it proceeds in higher yield for diterpenoid lactones than for lower molecular weight lactones. The structures of the 2,6-methano-bridged benzoxocin side products (23), (24), and (25) from rearrangement of the diterpenoid lactone (11) have been assigned.

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Surowiak, Alicja K., Lucyna Balcerzak, Stanisław Lochyński e Daniel J. Strub. "Biological Activity of Selected Natural and Synthetic Terpenoid Lactones". International Journal of Molecular Sciences 22, n. 9 (10 maggio 2021): 5036. http://dx.doi.org/10.3390/ijms22095036.

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Terpenoids with lactone moieties have been indicated to possess high bioactivity. Certain terpenoid lactones exist in nature, in plants and animals, but they can also be obtained by chemical synthesis. Terpenoids possessing lactone moieties are known for their cytotoxic, anti-inflammatory, antimicrobial, anticancer, and antimalarial activities. Moreover, one terpenoid lactone, artemisinin, is used as a drug against malaria. Because of these abilities, there is constant interest in new terpenoid lactones that are both isolated and synthesized, and their biological activities have been verified. In some cases, the activity of the terpenoid lactone is specifically connected to the lactone moiety. Recent works have revealed that new terpenoid lactones can demonstrate such functions and are thus considered to be potential active agents against many diseases.

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Klinotová, Eva, Václav Křeček, Jiří Klinot, Miloš Buděšínský, Jaroslav Podlaha, Jana Podlahová e Jiří Ječný. "An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride". Collection of Czechoslovak Chemical Communications 56, n. 12 (1991): 2917–35. http://dx.doi.org/10.1135/cccc19912917.

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3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

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7

Bergonzi, Celine, Michael Schwab, Eric Chabriere e Mikael Elias. "The quorum-quenching lactonase from Alicyclobacter acidoterrestris: purification, kinetic characterization, crystallization and crystallographic analysis". Acta Crystallographica Section F Structural Biology Communications 73, n. 8 (26 luglio 2017): 476–80. http://dx.doi.org/10.1107/s2053230x17010640.

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Lactonases comprise a class of enzymes that hydrolyze lactones, including acyl-homoserine lactones (AHLs); the latter are used as chemical signaling molecules by numerous Gram-negative bacteria. Lactonases have therefore been demonstrated to quench AHL-based bacterial communication. In particular, lactonases are capable of inhibiting bacterial behaviors that depend on these chemicals, such as the formation of biofilms or the expression of virulence factors. A novel representative from the metallo-β-lactamase superfamily, named AaL, was isolated from the thermoacidophilic bacterium Alicyclobacter acidoterrestris. Kinetic characterization proves AaL to be a proficient lactonase, with catalytic efficiencies (k cat/K m) against AHLs in the region of 105 M −1 s−1. AaL exhibits a very broad substrate specificity. Its structure is expected to reveal the molecular determinants for its substrate binding and specificity, as well as to provide grounds for future protein-engineering projects. Here, the expression, purification, characterization, crystallization and X-ray diffraction data collection of AaL at 1.65 Å resolution are reported.

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8

Tănase, Constantin, Lucia Pintilie e Raluca Elena Tănase. "Lactones in the Synthesis of Prostaglandins and Prostaglandin Analogs". International Journal of Molecular Sciences 22, n. 4 (4 febbraio 2021): 1572. http://dx.doi.org/10.3390/ijms22041572.

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In the total stereo-controlled synthesis of natural prostaglandins (PGs) and their structural analogs, a vast class of compounds and drugs, known as the lactones, are encountered in a few key steps to build the final molecule, as: δ-lactones, γ-lactones, and 1,9-, 1,11-, and 1,15-macrolactones. After the synthesis of 1,9-PGF2α and 1,15-PGF2α lactones, many 1,15-lactones of E2, E3, F2, F3, A2, and A3 were found in the marine mollusc Tethys fimbria and the quest for understanding their biological role stimulated the research on their synthesis. Then 1,9-, 1,11-, and 1,15-PG lactones of the drugs were synthesized as an alternative to the corresponding esters, and the first part of the paper describes the methods used for their synthesis. The efficient Corey procedure for the synthesis of prostaglandins uses the key δ-lactone and γ-lactone intermediates with three or four stereocenters on the cyclopentane fragment to link the PG side chains. The paper describes the most used procedures for the synthesis of the milestone δ-Corey-lactones and γ-Corey-lactones, their improvements, and some new promising methods, such as interesting, new stereo-controlled and catalyzed enantioselective reactions, and methods based on the chemical/enzymatic resolution of the compounds in different steps of the sequences. The many uses of δ-lactones not only for the synthesis of γ-lactones, but also for obtaining 9β-halogen-PGs and halogen-substituted cyclopentane intermediates, as synthons for new 9β-PG analogs and future applications, are also discussed.

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Gładkowski, Witold, Aleksandra Włoch, Aleksandra Pawlak, Angelika Sysak, Agata Białońska, Marcelina Mazur, Paweł Mituła, Gabriela Maciejewska, Bożena Obmińska-Mrukowicz e Halina Kleszczyńska. "Preparation of Enantiomeric β-(2′,5′-Dimethylphenyl)Bromolactones, Their Antiproliferative Activity and Effect on Biological Membranes". Molecules 23, n. 11 (20 novembre 2018): 3035. http://dx.doi.org/10.3390/molecules23113035.

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Three novel enantiomeric pairs of bromolactones possesing a 2,5-dimethylphenyl substituent at the β-position of the lactone ring have been synthesized from corresponding enantiomeric (E)-3-(2′,5′-dimethylphenyl)hex-4-enoic acids (4) by kinetically controlled bromolactonization with N-bromosuccinimide (NBS). γ-Bromo-δ-lactones (5) were isolated as the major products. Absolute configurations of stereogenic centers of γ-bromo-δ-lactones (5) were assigned based on X-ray analysis; configurations of cis δ-bromo-γ-lactones (6) and trans δ-bromo-γ-lactones (7) were determined based on mechanism of bromolactonization. Synthesized compounds exhibited significant antiproliferative activity towards the four canine cancer cell lines (D17, CLBL-1, CLB70, and GL-1) and one human cancer line (Jurkat). Classifying the compounds in terms of activity, the most active were enantiomers of trans δ-bromo-γ-lactones (7) followed by enantiomers of cis isomer (6) and enantiomeric γ-bromo-δ-lactones (5). Higher activity was observed for all stereoisomers with S configuration at C-4 in comparison with their enantiomers with 4R configuration. Synthesized compounds did not induce hemolysis of erythrocytes. The results of the interaction of bromolactones with red blood cell membranes suggest that these compounds incorporate into biological membranes, concentrating mainly in the hydrophilic part of the bilayer but have practically no influence on fluidity in the hydrophobic region. The differences in interactions with the membrane between particular enantiomers were observed only for γ-lactones: stronger interactions were found for enantiomer 4R,5R,6S of cis γ-lactone (6) and for enantiomer 4S,5R,6S of trans γ-lactone (7).

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High, Ryan, Phil Bremer, Biniam Kebede e Graham T. Eyres. "Comparison of Four Extraction Techniques for the Evaluation of Volatile Compounds in Spray-Dried New Zealand Sheep Milk". Molecules 24, n. 10 (18 maggio 2019): 1917. http://dx.doi.org/10.3390/molecules24101917.

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Recent growth and diversification of sheep milk products means more sophisticated methods are required to ensure their flavour quality. The objective of this study was to compare four extraction techniques for the analysis of volatile compounds in sheep milk by gas chromatography-mass spectrometry (GC-MS). Solvent Assisted Flavour Evaporation (SAFE), Solid Phase Microextraction (SPME), Headspace Sorptive Extraction (HSSE) and Stir Bar Sorptive Extraction (SBSE) were evaluated for their sensitivity, selectivity, reproducibility, and overall efficiency. A total of 48 volatile compounds from nine compound classes were identified in the spray-dried sheep milk. Alcohols, aldehydes, alkanes, carboxylic acids, ketones, lactones, sulphur compounds, nitrogen compounds, and terpenes were all present, but the differences between the methods were most apparent for lactones. SBSE extracted eight lactones, SAFE extracted four lactones and HSSE and SPME only detected trace levels of two lactones. Six of the lactones—δ-hexa-lactone, δ-octalactone, γ-decalactone, γ-dodecalactone, δ-tetradecalactone, and δ-hexadeca-lactone—were identified for the first time in spray-dried sheep milk. The present work demonstrated that SBSE is an effective tool for the extraction and analysis of volatiles, especially lactones, in sheep milk and dairy products in general. A discussion of the benefits and limitations of each method is included.

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Błoszyk, E., e B. Drożdż. "Sesquiterpene lactones. Part XXII. Sesquiterpene lactones in Species of the Genus Chrysanthemum". Acta Societatis Botanicorum Poloniae 47, n. 1–2 (2015): 3–13. http://dx.doi.org/10.5586/asbp.1978.001.

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A method of effective study on sesquiterpeine lactones in unknown plant material was worked out. This method allows the choice of species with high sesquiterpene lactones content and interesting chemical composition. Studies were carried out on 14 species of Chrysanthemum s.l.. The method of elementary appreciation consisted in: estimation of the bitter principle index (assayed by the modified Ph-P.IV. method), quantitative analysis of lactone fractions and chromatographical examination. Quantitative analysis of sesquiterpene lactones in plant material was carried out by the IR spectroscopy method specially adapted for this purpose. Chromatographic examinations were carried out by the thin-layer technique on silica gel. Chromatograms of lactone fractions were developed with 6 selective reagents. The correlation between the bitter principle index and quantitative content of sesquiterpene lactones was ascertained. Bisides great qualitative also quantitative differences were observed between 14 investigated species from Chrysanthemum s.l.

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Liu, Chen, Shao, Chen, Wu, Guo, Shi, Wang e Chu. "AhlX, an N-acylhomoserine Lactonase with Unique Properties". Marine Drugs 17, n. 7 (28 giugno 2019): 387. http://dx.doi.org/10.3390/md17070387.

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N-Acylhomoserine lactonase degrades the lactone ring of N-acylhomoserine lactones (AHLs) and has been widely suggested as a promising candidate for use in bacterial disease control. While a number of AHL lactonases have been characterized, none of them has been developed as a commercially available enzymatic product for in vitro AHL quenching due to their low stability. In this study, a highly stable AHL lactonase (AhlX) was identified and isolated from the marine bacterium Salinicola salaria MCCC1A01339. AhlX is encoded by a 768-bp gene and has a predicted molecular mass of 29 kDa. The enzyme retained approximately 97% activity after incubating at 25 °C for 12 days and ~100% activity after incubating at 60 °C for 2 h. Furthermore, AhlX exhibited a high salt tolerance, retaining approximately 60% of its activity observed in the presence of 25% NaCl. In addition, an AhlX powder made by an industrial spray-drying process attenuated Erwinia carotovora infection. These results suggest that AhlX has great potential for use as an in vitro preventive and therapeutic agent for bacterial diseases.

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Porzio, Elena, Davide Andrenacci e Giuseppe Manco. "Thermostable Lactonases Inhibit Pseudomonas aeruginosa Biofilm: Effect In Vitro and in Drosophila melanogaster Model of Chronic Infection". International Journal of Molecular Sciences 24, n. 23 (1 dicembre 2023): 17028. http://dx.doi.org/10.3390/ijms242317028.

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Pseudomonas aeruginosa is one of the six antimicrobial-resistant pathogens known as “ESKAPE” that represent a global threat to human health and are considered priority targets for the development of novel antimicrobials and alternative therapeutics. The virulence of P. aeruginosa is regulated by a four-chemicals communication system termed quorum sensing (QS), and one main class of QS signals is termed acylhomoserine lactones (acyl-HSLs), which includes 3-Oxo-dodecanoil homoserine lactone (3-Oxo-C12-HSL), which regulates the expression of genes implicated in virulence and biofilm formation. Lactonases, like Paraoxonase 2 (PON2) from humans and the phosphotriesterase-like lactonases (PLLs) from thermostable microorganisms, are able to hydrolyze acyl-HSLs. In this work, we explored in vitro and in an animal model the effect of some lactonases on the production of Pseudomonas virulence factors. This study presents a model of chronic infection in which bacteria were administered by feeding, and Drosophila adults were treated with enzymes and the antibiotic tobramycin, alone or in combination. In vitro, we observed significant effects of lactonases on biofilm formation as well as effects on bacterial motility and the expression of virulence factors. The treatment in vivo by feeding with the lactonase SacPox allowed us to significantly increase the biocidal effect of tobramycin in chronic infection.

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Gładkowski, Witold, Monika Siepka, Barbara Żarowska, Agata Białońska, Barbara Gawdzik, Mariusz Urbaniak e Czesław Wawrzeńczyk. "Chalcone-Derived Lactones: Synthesis, Whole-Cell Biotransformation, and Evaluation of Their Antibacterial and Antifungal Activity". Molecules 28, n. 9 (28 aprile 2023): 3800. http://dx.doi.org/10.3390/molecules28093800.

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Four compounds with lactone moiety were synthesized from chalcone 1 in three- or four-step synthesis. γ-Bromo-δ-lactone 5 was the only product of bromolactonization of acid 4 whereas bromolactonization of ester 3, apart from lactone 5 also afforded its isomer 6 and two diastereoisomeric δ-hydroxy-γ-lactones 7 and 8. Lactone 8 was also obtained in 88% yield as a product of simultaneous dehalogenation and translactonization of γ-bromo-δ-lactone 5 by Penicillum frequentans AM 359. Chalcone-derived lactones 5–8 were subjected to the tests on antimicrobial activity and the results compared with activity of starting chalcone 1. Obtained lactones 5–8 in most cases limited the growth of tested bacterial and fungal strains. The highest activity was found for δ-hydroxy-γ-lactone 8 which completely inhibited the growth of Staphylococcus aureus, Fusarium graminearum, Aspergillus niger, and Alternaria sp. The introduction of lactone moiety into chalcone scaffold significantly improved antimicrobial activity of the compound: γ-bromo-δ-lactone 6 and δ-hydroxy-γ-lactone 8 were significantly stronger growth inhibitors of S. aureus and F. graminearum. In the case of the latter, a clear positive effect of the lactone function on the antifungal activity was also observed for γ-bromo-δ-lactone 5.

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Gładkowski, Witold, Monika Siepka, Tomasz Janeczko, Edyta Kostrzewa-Susłow, Jarosław Popłoński, Marcelina Mazur, Barbara Żarowska, Wojciech Łaba, Gabriela Maciejewska e Czesław Wawrzeńczyk. "Synthesis and Antimicrobial Activity of Methoxy- Substituted γ-Oxa-ε-lactones Derived from Flavanones". Molecules 24, n. 22 (16 novembre 2019): 4151. http://dx.doi.org/10.3390/molecules24224151.

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Six γ-oxa-ε-lactones, 4-phenyl-3,4-dihydro-2H-1,5-benzodioxepin-2-one (5a) and its five derivatives with methoxy groups in different positions of A and B rings (5b–f), were synthesized from corresponding flavanones. Three of the obtained lactones (5b,c,f) have not been previously described in the literature. Structures of all synthesized compounds were confirmed by complete spectroscopic analysis with the assignments of signals on 1H and 13C-NMR spectra to the corresponding atoms. In most cases, lactones 5a–f exerted an inhibitory effect on the growth of selected pathogenic bacteria (Escherichia coli, Bacillus subtilis, and Staphylococcus aureus), filamentous fungi (Fusarium graminearum, Aspergillus niger, and Alternaria sp.), and yeast (Candida albicans). The broadest spectrum of activity was observed for unsubstituted lactone 5a, which was particularly active against filamentous fungi and yeast. Lactones with methoxy groups in the 3′ (5c) and 4′ (5d) position of B ring were more active towards bacteria whereas lactone substituted in the 7 position of the A ring (5e) exhibited higher antifungal activity. In most cases, the introduction of lactone function increased the activity of the compound compared to its flavonoid precursors, chalcones 3a–e, and flavanones 4a–f.

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Dancewicz, Katarzyna, Barbara Ratuś, Filip Boratyński, Bożena Kordan, Beata Gabryś e Czesław Wawrzeńczyk. "Effect of Oxygen Incorporation into Cyclohexanone Ring on Antifeedant Activity". Journal of Plant Protection Research 51, n. 1 (1 gennaio 2011): 23–28. http://dx.doi.org/10.2478/v10045-011-0005-0.

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Effect of Oxygen Incorporation into Cyclohexanone Ring on Antifeedant ActivityThe behaviour of the peach potato aphidMyzus persicae(Sulz.) was studied during settling on plants. The experiment involved observing peach potato aphid activity after the application of some natural and synthetic cyclohexanones and the, respective ε-lactones and epoxy-ε-lactones which were obtained from the cyclohexanones. Stereochemistry, and the number and position of methyl substituents were important for the biological activity of the starting compounds: only trimethyl-substituted cyclohexanones were active,i.e.3.3.5-trimethylcyclohexanone (deterrent) and 2.2.6-trimethylcyclohexanone (attractant). The effect of oxygen incorporation into the cyclohexanone ring on deterrent activity varied depending on the starting compound. The ε-lactones that derived from saturated cyclohexanones were either weak attractants or were inactive, except the deterrent ε-lactone with three methyl groups at positions 3.7.7. None of the products of unsaturated ketone isophorone (weak deterrent) oxidation,i.e.epoxy isophorone, epoxy lactone, or unsaturated lactone, affected aphid settling. Of the two epoxy ketones obtained from (+)-dihydrocarvone that was inactive, only (2S, 5S)-2-methyl-5-((S)-1-methyloxiranyl)-cyclohexanone was a strong deterrent. Both epoxy-ε-lactones that derived from (+)-dihydrocarvone were strong deterrents.

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Lutter, E., S. Lewenza, J. J. Dennis, M. B. Visser e P. A. Sokol. "Distribution of Quorum-Sensing Genes in the Burkholderia cepacia Complex". Infection and Immunity 69, n. 7 (1 luglio 2001): 4661–66. http://dx.doi.org/10.1128/iai.69.7.4661-4666.2001.

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ABSTRACT The distribution of quorum-sensing genes among strains from seven genomovars of the Burkholderia cepaciacomplex was examined by PCR. cepR and cepI were amplified from B. cepacia genomovars I and III, B. stabilis, and B. vietnamiensis. cepR was also amplified from B. multivorans and B. cepacia genomovar VI. bviIR were amplified from B. vietnamiensis. All genomovars producedN-octanoyl-l-homoserine lactone andN-hexanoyl-l-homoserine lactone.B. vietnamiensis and B. cepacia genomovar VII produced additional N-acyl-l-homoserine lactones.

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Majerczyk, Charlotte, Loren Kinman, Tony Han, Richard Bunt e E. Peter Greenberg. "Virulence of Burkholderia mallei Quorum-Sensing Mutants". Infection and Immunity 81, n. 5 (19 febbraio 2013): 1471–78. http://dx.doi.org/10.1128/iai.00048-13.

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ABSTRACTManyProteobacteriause acyl-homoserine lactone-mediated quorum-sensing (QS) to activate specific sets of genes as a function of cell density. QS often controls the virulence of pathogenic species, and in fact a previous study indicated that QS was important forBurkholderia malleimouse lung infections. To gain in-depth information on the role of QS inB. malleivirulence, we constructed and characterized a mutant ofB. malleistrain GB8 that was unable to make acyl-homoserine lactones. The QS mutant showed virulence equal to that of its wild-type parent in an aerosol mouse infection model, and growth in macrophages was indistinguishable from that of the parent strain. Furthermore, we assessed the role of QS inB. malleiATCC 23344 by constructing and characterizing a mutant strain producing AiiA, a lactonase enzyme that degrades acyl-homoserine lactones. Although acyl-homoserine lactone levels in cultures of this strain are very low, it showed full virulence. Contrary to the previous report, we conclude that QS is not required for acuteB. malleiinfections of mice. QS may be involved in some stage of chronic infections in the natural host of horses, or the QS genes may be remnants of the QS network inB. pseudomalleifrom which this host-adapted pathogen evolved.

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Borchardt, S. A., E. J. Allain, J. J. Michels, G. W. Stearns, R. F. Kelly e W. F. McCoy. "Reaction of Acylated Homoserine Lactone Bacterial Signaling Molecules with Oxidized Halogen Antimicrobials". Applied and Environmental Microbiology 67, n. 7 (1 luglio 2001): 3174–79. http://dx.doi.org/10.1128/aem.67.7.3174-3179.2001.

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ABSTRACT Oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. Recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in Pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. This study was conducted to investigate the potential for oxidized halogens to react with acylated homoserine lactone-based signaling molecules. Acylated homoserine lactones containing a 3-oxo group were found to rapidly react with oxidized halogens, while acylated homoserine lactones lacking the 3-oxo functionality did not react. The Chromobacterium violaceum CV026 bioassay was used to determine the effects of such reactions on acylated homoserine lactone activity. The results demonstrated that 3-oxo acyl homoserine lactone activity was rapidly lost upon exposure to oxidized halogens; however, acylated homoserine lactones lacking the 3-oxo group retained activity. Experiments with the marine alga Laminaria digitata demonstrated that natural haloperoxidase systems are capable of mediating the deactivation of acylated homoserine lactones. This may illustrate a natural defense mechanism to prevent biofouling on the surface of this marine alga. The Chromobacterium violaceum activity assay illustrates that reactions between 3-oxo acylated homoserine lactone molecules and oxidized halogens do occur despite the presence of biofilm components at much greater concentrations. This work suggests that oxidized halogens may control biofilm not only via a cidal mechanism, but also by possibly interfering with 3-oxo acylated homoserine lactone-based cell signaling.

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20

Włoch, Aleksandra, Dominika Stygar, Fouad Bahri, Barbara Bażanów, Piotr Kuropka, Elżbieta Chełmecka, Hanna Pruchnik e Witold Gładkowski. "Antiproliferative, Antimicrobial and Antiviral Activity of β-Aryl-δ-iodo-γ-lactones, Their Effect on Cellular Oxidative Stress Markers and Biological Membranes". Biomolecules 10, n. 12 (24 novembre 2020): 1594. http://dx.doi.org/10.3390/biom10121594.

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The aim of this work was the examination of biological activity of three selected racemic cis-β-aryl-δ-iodo-γ-lactones. Tested iodolactones differed in the structure of the aromatic fragment of molecule, bearing isopropyl (1), methyl (2), or no substituent (3) on the para position of the benzene ring. A broad spectrum of biological activity as antimicrobial, antiviral, antitumor, cytotoxic, antioxidant, and hemolytic activity was examined. All iodolactones showed bactericidal activity against Proteus mirabilis, and lactones 1,2 were active against Bacillus cereus. The highest cytotoxic activity towards HeLa and MCF7 cancer cell lines and NHDF normal cell line was found for lactone 1. All assessed lactones significantly disrupted antioxidative/oxidative balance of the NHDF, and the most harmful effect was determined by lactone 1. Contrary to lactone 1, lactones 2 and 3 did not induce the hemolysis of erythrocytes after 48 h of incubation. The differences in activity of iodolactones 1–3 in biological tests may be explained by their different impact on physicochemical properties of membrane as the packing order in the hydrophilic area and fluidity of hydrocarbon chains. This was dependent on the presence and type of alkyl substituent. The highest effect on the membrane organization was observed for lactone 1 due to the presence of bulky isopropyl group on the benzene ring.

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21

Semakov, A. V., L. V. Anikina e S. G. Klochkov. "Synthesis and Cytotoxic Activity of the Products of Addition of Thiophenol to Sesquiterpene Lactones". Russian Journal of Bioorganic Chemistry 47, n. 4 (luglio 2021): 906–17. http://dx.doi.org/10.1134/s106816202104018x.

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Abstract— Derivatives of sesquiterpene lactones modified at the lactone ring with a thiophenol residue have been synthesized. The resulting conjugates with thiophenol have capacity for the oxidation–elimination reaction by the action of ROS of a tumor cell with the release of initial cytotoxic lactones. It has been proposed to use the resulting sulfur-containing conjugates as ROS-activated prodrugs of sesquiterpene lactones. The antiproliferative properties of the conjugates have been examined on tumor and pseudonormal cell lines. The cytotoxicity of the conjugates is lower than that of parent lactones; however, in some cases, as with the conjugates of alantolactone with artemisiten, it remains moderate in all tumor cell lines tested.

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22

Hakobyan, Robert M., Levon A. Kharatyan, Sargis S. Hayotsyan, Hovhannes S. Attaryan e Gagik S. Melikyan. "SYNTHESIS OF NEW γ-LACTONE RING DERIVATIVES CONTAINING PYRIDINE AND TRICONDENSED SYSTEMS". ChemChemTech 67, n. 7 (30 maggio 2024): 28–40. http://dx.doi.org/10.6060/ivkkt.20246707.7068.

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Abstract (sommario):

Lactone-pyridone rings contain many biologically active molecules of natural and artificial origin. The molecules contained in these two rings, represented by Cerpegine and its derivatives, will also exhibit high biological activity. It is also necessary to take into account that both natural and synthetic multi-substituted lactones have high biological activity. Thus, research in the field of multi-substituted lactones and further transformations are of particular interest. The synthesis of such systems began with the synthesis of a 2-acetylfuranone ring. In the next step, condensation of ethylcyanoacetate with 2-acetylfuranone by Knewenegel produced 3-substituted lactones, which according to the NMP 1H spectroscopy are a mixture of E and Z isomers. Then, when 3-substituted lactones were heated with dimethylformamide dimethylacetal DMFA/DMA, 3-substituted lactones containing a diene fragment in the structure were obtained. Stereoselective attachment E was detected using the NMR 1H spectrum. Then, under the action of the corresponding amine, the intermolecular substitution reactions produce compounds containing a lactone and pyridine group isolated by a σ-bond (serpegenous compound). Due to the proximity of the cyanide group of the pyridine ring and the fourth blight group of the lactone ring, intramolecular cyclization occurs during heating in the alkaline medium to form new tricondensed systems. Thus, an optimal method of synthesis of serpegenous compounds has been developed. These systems are of interest because in their skeleton they have not only a condensed system but also spirocycles. The connections themselves may be a promise for further exploration. For citation: Hakobyan R.M., Kharatyan L.A., Hayotsyan S.S., Attaryan H.S., Melikyan G.S. Synthesis of new γ-lactone ring derivatives containing pyridine and tricondensed systems. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 28-40. DOI: 10.6060/ivkkt.20246707.7068.

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23

Aertker, Kristina M. J., H. T. Henry Chan, Christopher T. Lohans e Christopher J. Schofield. "Analysis of β-lactone formation by clinically observed carbapenemases informs on a novel antibiotic resistance mechanism". Journal of Biological Chemistry 295, n. 49 (22 settembre 2020): 16604–13. http://dx.doi.org/10.1074/jbc.ra120.014607.

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An important mechanism of resistance to β-lactam antibiotics is via their β-lactamase–catalyzed hydrolysis. Recent work has shown that, in addition to the established hydrolysis products, the reaction of the class D nucleophilic serine β-lactamases (SBLs) with carbapenems also produces β-lactones. We report studies on the factors determining β-lactone formation by class D SBLs. We show that variations in hydrophobic residues at the active site of class D SBLs (i.e. Trp105, Val120, and Leu158, using OXA-48 numbering) impact on the relative levels of β-lactones and hydrolysis products formed. Some variants, i.e. the OXA-48 V120L and OXA-23 V128L variants, catalyze increased β-lactone formation compared with the WT enzymes. The results of kinetic and product studies reveal that variations of residues other than those directly involved in catalysis, including those arising from clinically observed mutations, can alter the reaction outcome of class D SBL catalysis. NMR studies show that some class D SBL variants catalyze formation of β-lactones from all clinically relevant carbapenems regardless of the presence or absence of a 1β-methyl substituent. Analysis of reported crystal structures for carbapenem-derived acyl-enzyme complexes reveals preferred conformations for hydrolysis and β-lactone formation. The observation of increased β-lactone formation by class D SBL variants, including the clinically observed carbapenemase OXA-48 V120L, supports the proposal that class D SBL-catalyzed rearrangement of β-lactams to β-lactones is important as a resistance mechanism.

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24

Barbosa, Luiz Claúdio de A., Adilson V. Costa, Dorila Piló-Veloso, Joao Luiz C. Lopes, Manuel G. Hernandez-Terrones, Beatriz King-Diaz e Blas Lotina-Hennsen. "Phytogrowth-Inhibitory Lactones Derivatives of Glaucolide B". Zeitschrift für Naturforschung C 59, n. 11-12 (1 dicembre 2004): 803–10. http://dx.doi.org/10.1515/znc-2004-11-1207.

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The sesquiterpene lactone glaucolide B (1), isolated from Vernonia fruticulosa (Asteraceae), was transformed into six lactones (2-7). The structures of the products were elucidated by spectroscopic analysis. A series of solutions of compounds 1-7, at 200 μᴍ, were tested on the germination and on the root and shoot growth of the dicotyledons Physalis ixocarpa and Trifolium alexandrinum and of the monocotyledons Lolium multiflorum and Amaranthus hypochondriacus. Lactone 5 exhibited clear selectivity towards dicotyledonous species at 200 μᴍ, with an average inhibition of 90% on the germination of P. ixocarpa. Lactones 1, 3 and 4 had a greater effect on root length of monocotyledonous species, inhibiting around 70% at 200 μᴍ in L. multiflorum. It seems that the diol function is required in lactones 4-6 to increase the activity, the polarity in the molecule might be required to reach its target.

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25

Chany, Anne-Caroline, Léo B. Marx e Jonathan W. Burton. "Synthesis of bicyclic tetrahydrofurans from linear precursors using manganese(iii) acetate". Organic & Biomolecular Chemistry 13, n. 35 (2015): 9190–93. http://dx.doi.org/10.1039/c5ob01091h.

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Abstract (sommario):

Cyclisation of a range of alkoxy-malonates in the presence of manganese(iii) acetate gives rise to bicyclic lactone/THFs and lactone/lactones in synthetically useful yields and diastereoselectivities.

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26

Bińczak, Jakub, Krzysztof Dziuba e Anna Chrobok. "Recent Developments in Lactone Monomers and Polymer Synthesis and Application". Materials 14, n. 11 (27 maggio 2021): 2881. http://dx.doi.org/10.3390/ma14112881.

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Abstract (sommario):

Lactones are a group of compounds that have been known for several decades. The commercial importance of lactones results from the possibility of manufacturing of a broad scope of derivatives and polymers with a wide spectrum of applications. In this work the synthesis and characterization of simple lactones are described, which due to the easy methods of the synthesis are of high importance for the industry. The chemical as well as biochemical methods are included with special attention paid to the methods that avoid metal catalysts, initiators or toxic solvents, allowing the use of the final products for the medical applications, e.g., for controlled drug-release systems, resorbable surgical threads, implants, tissue scaffolds or for the production of drugs. Lactone-based derivatives, such as polymers, copolymers, composites or three-dimensional structures are also presented. The work is focused on the methods for the synthesis of lactones and lactones derivates, as well as on the special properties and application of the studied compounds.

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27

Mazur, Marcelina, e Dorota Masłowiec. "Antimicrobial Activity of Lactones". Antibiotics 11, n. 10 (29 settembre 2022): 1327. http://dx.doi.org/10.3390/antibiotics11101327.

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Abstract (sommario):

The development of bacterial resistance to antibiotics and the consequent lack of effective therapy is one of the biggest problems in modern medicine. A consequence of these processes is an urgent need to continuously design and develop novel antimicrobial agents. Among the compounds showing antimicrobial potential, lactones are a group to explore. For centuries, their antimicrobial activities have been used in folk medicine. Currently, novel lactone compounds are continuously described in the literature. Some of those structures exhibit high antimicrobial potential and some are an inspiration for design and synthesis of future drugs. This paper describes recent developments on antimicrobial lactones with smaller ring sizes, up to seven membered ε-lactones. Their isolation from natural sources, chemical synthesis, synergistic activity with antibiotics, and effects on quorum sensing are presented herein.

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28

Błoszyk, Ełżbieta, Aleksandra Dudek, Zofia Kosturkiewicz, Urszula Rychłewska, Włodzimierz M. Daniewski, Maria Gulumka, Jan Nawrot, Miloš Buděšínský, Soňa Vašíčková e Miroslav Holub. "Sesquiterpene lactones of Cephalophora aromatica (HOOK.) SCHRADER and their deterrent activity. The stereostructure of geigerinin". Collection of Czechoslovak Chemical Communications 54, n. 7 (1989): 1903–18. http://dx.doi.org/10.1135/cccc19891903.

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Abstract (sommario):

From species Cephalophora aromatica (HOOK.) SCHRADER the authors isolated a series of previously described sesquiterpene lactones I-V and newly the lactone geigerinin (VI). Its structure was confirmed by X-ray analysis and its absolute configuration was determined on the basis of the CD spectra of its complex with Pr(thd)3. The lactones I-VII were tested for antifeedant activity against main crop pests.

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29

Tang, Kaihao, Ying Su, Gilles Brackman, Fangyuan Cui, Yunhui Zhang, Xiaochong Shi, Tom Coenye e Xiao-Hua Zhang. "MomL, a Novel Marine-DerivedN-Acyl Homoserine Lactonase from Muricauda olearia". Applied and Environmental Microbiology 81, n. 2 (14 novembre 2014): 774–82. http://dx.doi.org/10.1128/aem.02805-14.

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ABSTRACTGram-negative bacteria useN-acyl homoserine lactones (AHLs) as quorum sensing (QS) signaling molecules for interspecies communication, and AHL-dependent QS is related with virulence factor production in many bacterial pathogens. Quorum quenching, the enzymatic degradation of the signaling molecule, would attenuate virulence rather than kill the pathogens, and thereby reduce the potential for evolution of drug resistance. In a previous study, we showed thatMuricauda oleariaTh120, belonging to the classFlavobacteriia, has strong AHL degradative activity. In this study, an AHL lactonase (designated MomL), which could degrade both short- and long-chain AHLs with or without a substitution ofoxo-group at the C-3 position, was identified from Th120. Liquid chromatography-mass spectrometry analysis demonstrated that MomL functions as an AHL lactonase catalyzing AHL degradation through lactone hydrolysis. MomL is an AHL lactonase belonging to the metallo-β-lactamase superfamily that harbors an N-terminal signal peptide. The overall catalytic efficiency of MomL for C6-HSL is ∼2.9 × 105s−1M−1. Metal analysis and site-directed mutagenesis showed that, compared to AiiA, MomL has a different metal-binding capability and requires the histidine and aspartic acid residues for activity, while it shares the “HXHXDH” motif with other AHL lactonases belonging to the metallo-β-lactamase superfamily. This suggests that MomL is a representative of a novel type of secretory AHL lactonase. Furthermore, MomL significantly attenuated the virulence ofPseudomonas aeruginosain aCaenorhabditis elegansinfection model, which suggests that MomL has the potential to be used as a therapeutic agent.

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30

Mandal, Sudip Kumar, Utsab Debnath, Amresh Kumar, Sabu Thomas, Subhash Chandra Mandal, Manabendra Dutta Choudhury e Partha Palit. "Natural Sesquiterpene Lactones in the Prevention and Treatment of Inflammatory Disorders and cancer: A Systematic Study of this Emerging Therapeutic Approach based on Chemical and Pharmacological Aspect". Letters in Drug Design & Discovery 17, n. 9 (11 settembre 2020): 1102–16. http://dx.doi.org/10.2174/1570180817999200421144007.

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Abstract (sommario):

Background and Introduction: Sesquiterpene lactones are a class of secondary metabolite that contains sesquiterpenoids and lactone ring as pharmacophore moiety. A large group of bioactive secondary metabolites such as phytopharmaceuticals belong to this category. From the Asteraceae family-based medicinal plants, more than 5,000 sesquiterpene lactones have been reported so far. Sesquiterpene lactone-based pharmacophore moieties hold promise for broad-spectrum biological activities against cancer, inflammation, parasitic, bacterial, fungal, viral infection and other functional disorders. Moreover, these moiety based phytocompounds have been highlighted with a new dimension in the natural drug discovery program worldwide after the 2015 Medicine Nobel Prize achieved by the Artemisinin researchers. Objective: These bitter substances often contain an α, β-unsaturated-γ-lactone as a major structural backbone, which in recent studies has been explored to be associated with anti-tumor, cytotoxic, and anti-inflammatory action. Recently, the use of sesquiterpene lactones as phytomedicine has been increased. This study will review the prospect of sesquiterpene lactones against inflammation and cancer. Methods: Hence, we emphasized on the different features of this moiety by incorporating its structural diversity on biological activities to explore structure-activity relationships (SAR) against inflammation and cancer. Results: How the dual mode of action such as anti-inflammatory and anti-cancer has been exhibitedby these phytopharmaceuticals will be forecasted in this study. Furthermore, the correlation of anti-inflammatory and anti-cancer activity executed by the sesquiterpene lactones for fruitful phytotherapy will also be revealed in the present review in the milieu of pharmacophore activity relation and pharmacodynamics study as well. Conclusion: So, these metabolites are paramount in phytopharmacological aspects. The present discussion on the future prospect of this moiety based on the reported literature could be a guide for anti-inflammatory and anti-cancer drug discovery programs for the upcoming researchers.

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Kim, Younghoon, Sandip Sengupta e Taebo Sim. "Natural and Synthetic Lactones Possessing Antitumor Activities". International Journal of Molecular Sciences 22, n. 3 (21 gennaio 2021): 1052. http://dx.doi.org/10.3390/ijms22031052.

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Abstract (sommario):

Cancer is one of the leading causes of death globally, accounting for an estimated 8 million deaths each year. As a result, there have been urgent unmet medical needs to discover novel oncology drugs. Natural and synthetic lactones have a broad spectrum of biological uses including anti-tumor, anti-helminthic, anti-microbial, and anti-inflammatory activities. Particularly, several natural and synthetic lactones have emerged as anti-cancer agents over the past decades. In this review, we address natural and synthetic lactones focusing on their anti-tumor activities and synthetic routes. Moreover, we aim to highlight our journey towards chemical modification and biological evaluation of a resorcylic acid lactone, L-783277 (4). We anticipate that utilization of the natural and synthetic lactones as novel scaffolds would benefit the process of oncology drug discovery campaigns based on natural products.

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Husinec, Suren, e Vladimir Savic. "The synthesis of some unsaturated 4-substituted-g-lactones". Journal of the Serbian Chemical Society 65, n. 2 (2000): 87–93. http://dx.doi.org/10.2298/jsc0002087h.

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Abstract (sommario):

The synthesis of conjugated and nonconjugated unsaturated 4-substituted lactones of type 1 and 2 are described. The type 1 lactone was prepared by a two step procedure employing Bredereck's reagent. The type 2 lactone was synthesised by combining the Claisen-Ireland rearrangement and selenolactonisation.

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33

Pawlak, Aleksandra, Marta Henklewska, Beatriz Hernández-Suárez, Monika Siepka, Witold Gładkowski, Czesław Wawrzeńczyk, Karolina Motykiewicz-Pers e Bożena Obmińska-Mrukowicz. "Methoxy-Substituted γ-Oxa-ε-Lactones Derived from Flavanones—Comparison of Their Anti-Tumor Activity In Vitro". Molecules 26, n. 20 (18 ottobre 2021): 6295. http://dx.doi.org/10.3390/molecules26206295.

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Abstract (sommario):

Background: The study investigated four flavanone-derived γ-oxa-ε-lactones: a parent unsubstituted compound and its three derivatives with the methoxy group in positions 2′, 4′ and 8. Our objective was to find out if the introduction of the methoxy group into the aromatic ring affects in vitro anti-tumor potency of the investigated lactones. Methods: Cytotoxic and pro-apoptotic effects were assessed with cytometric tests with propidium iodide, annexin V, and Western blot techniques. We also investigated potential synergistic potency of the tested lactones and glucocorticoids in canine lymphoma/leukemia cell lines. Results: The tested flavanone-derived lactones showed anti-cancer activity in vitro. Depending on its location, the methoxy group either increased or decreased cytotoxicity of the derivatives as compared with the parent compound. The most potent lactone was the one with the methoxy group at position 4′ of the B ring (compound 3), and the weakest activity was observed when the group was located at C-8 in the A ring. A combination of the lactones with glucocorticoids confirmed their synergy in anti-tumor activity in vitro. Conclusions: Methoxy-substituted flavanone-derived lactones effectively kill canine lymphoma/leukemia cells in vitro and, thanks to their synergistic action with glucocorticoids, may potentially be applied in the treatment of hematopoietic cancers.

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Silva, Rui, Eduardo Coelho, Tatiana Q. Aguiar e Lucília Domingues. "Microbial Biosynthesis of Lactones: Gaps and Opportunities towards Sustainable Production". Applied Sciences 11, n. 18 (13 settembre 2021): 8500. http://dx.doi.org/10.3390/app11188500.

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Abstract (sommario):

Lactones are volatile organic compounds widely present in foods. These chemicals are applied as flavors and fragrances in the food, cosmetics and pharmaceutical industries. Recently, the potential of lactones as green solvents and fuel precursors reinforced their role as platform compounds of future bio-based economies. However, their current mode of production needs to change. Lactones are mainly obtained through chemical synthesis or microbial biotransformation of hydroxy fatty acids. The latter approach is preferred but still needs to use more sustainable substrates. Hydroxy fatty acids are non-abundant and non-sustainable substrates from environmental, health and economic points of view. Therefore, it is urgent to identify and engineer microorganisms with the rare ability to biosynthesize lactones from carbohydrates or renewable lipids. Here, we firstly address the variety and importance of lactones. Then, the current understanding of the biosynthetic pathways involved in lactone biosynthesis is presented, making use of the knowledge acquired in microorganisms and fruits. From there, we present and make the distinction between biotransformation processes and de novo biosynthesis of lactones. Finally, the opportunities and challenges towards more sustainable production in addition to the relevance of two well-known industrial microbes, the filamentous fungus Ashbya gossypii and the yeast Yarrowia lipolytica, are discussed.

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Mukhidova, Zulfiya Sh, Salakhutdin H. Zakirov, Sevara M. Khazratkulova e Nodira T. Zakirova. "Prospects for the use of natural terpenoids in agriculture". BIO Web of Conferences 82 (2024): 03001. http://dx.doi.org/10.1051/bioconf/20248203001.

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Abstract (sommario):

As a result of the conducted phytochemical studies of sesquiterpene lactones of some plants of the genus Artemisia, Centaurea, Jurinea, and Handelia of the Asteraceae family and the study of biostimulating, mutagenic, and insecticidal activity of isolated individual lactones and total preparations in rice farming, cotton growing, as well as against termites, the following biologically active environmentally safe natural remedies have been created: an effective stimulant that, when soaking rice seeds, increases the yield 12-14 quintals per hectare as an average, promising mutant lines and two new cotton varieties have been created on the basis of the polar lactone sum (PLS), and anti-termite sesquiterpene lactones have been isolated, which at low concentrations destroy termites by 90-96%.

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36

Chan, Ying Ying, Hao Sheng Bian, Theresa May Chin Tan, Margrith E. Mattmann, Grant D. Geske, Jun Igarashi, Tomomi Hatano, Hiroaki Suga, Helen E. Blackwell e Kim Lee Chua. "Control of Quorum Sensing by a Burkholderia pseudomallei Multidrug Efflux Pump". Journal of Bacteriology 189, n. 11 (23 marzo 2007): 4320–24. http://dx.doi.org/10.1128/jb.00003-07.

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Abstract (sommario):

ABSTRACT The Burkholderia pseudomallei KHW quorum-sensing systems produced N-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-(3-hydroxy)-octanoyl-homoserine lactone, N-(3-hydroxy)-decanoyl-homoserine lactone, N-(3-oxo)-decanoyl-homoserine lactone, and N-(3-oxo)-tetradecanoyl-homoserine lactone. The extracellular secretion of these acyl-homoserine lactones is dependent absolutely on the function of the B. pseudomallei BpeAB-OprB efflux pump.

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Lynch, MJ, J. Simpson e RT Weavers. "Diiodo Acetals and Unsaturated Lactones From Dihydropyran". Australian Journal of Chemistry 46, n. 2 (1993): 203. http://dx.doi.org/10.1071/ch9930203.

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Abstract (sommario):

Reaction of dihydropyran with propiolic acid and N- iodosuccinimide gave an iodo ester which was cyclized under free-radical conditions to form an (E) iodomethylene lactone. Photolysis of this lactone could be controlled to generate mixtures of (E) and (Z) iodomethylene lactones, or alternatively the iodine-free methylene lactone. The structures of some by-products of the iodo ester formation have been shown to be a succinimide derivative and two stereoisomers of a diiodo acetal. X-Ray determination of the structure of one of the diiodo acetal isomers is described.

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38

Deslongchamps, Pierre, Daniel Guay e Robert Chènevert. "The hydrolysis of cis and trans methoxy bicyclic and tricyclic orthoesters. Evidence for a chair–boat inversion prior to breakdown in some hemiorthoester tetrahedral intermediates". Canadian Journal of Chemistry 63, n. 9 (1 settembre 1985): 2493–500. http://dx.doi.org/10.1139/v85-413.

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Abstract (sommario):

The acid hydrolysis of cis and trans methoxy bicyclic and tricyclic orthoesters 1–4 was studied. The trans isomers gave only the corresponding hydroxy-lactones (2 → 14 and 4 → 16 + 10) whereas the cis isomers gave mixtures of dihydroxy-esters and hydroxy-lactones (1 → 13 + 14) and 3 → 15 + 16 + 10). These results are rationalized on the basis of the stereoelectronic theory for hydrolytic processes. The fact that hydroxy-lactone 16 is produced to a larger extent than the isomeric hydroxy-lactone 10 is taken as evidence that when a tetrahedral intermediate is not allowed (stereoelectronically) to break down in a chair conformation, it will take a boat form prior to cleavage.

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39

NANTASENAMAT, CHANIN, THEERAPHON PIACHAM, TANAWUT TANTIMONGCOLWAT, THANAKORN NAENNA, CHARTCHALERM ISARANKURA-NA-AYUDHYA e VIRAPONG PRACHAYASITTIKUL. "QSAR MODEL OF THE QUORUM-QUENCHING N-ACYL-HOMOSERINE LACTONE LACTONASE ACTIVITY". Journal of Biological Systems 16, n. 02 (giugno 2008): 279–93. http://dx.doi.org/10.1142/s021833900800254x.

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Abstract (sommario):

A quantitative structure-activity relationship (QSAR) study was performed to model the lactonolysis activity of N-acyl-homoserine lactone lactonase. A data set comprising of 20 homoserine lactones and related compounds was taken from the work of Wang et al. Quantum chemical descriptors were calculated using the semiempirical AM1 method. Partial least squares regression was utilized to construct a predictive model. This computational approach reliably reproduced the lactonolysis activity with high accuracy as illustrated by the correlation coefficient in excess of 0.9. It is demonstrated that the combined use of quantum chemical descriptors with partial least squares regression are suitable for modeling the AHL lactonolysis activity.

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40

Liu, Ling-Pu, Long-Hui Huang, Xiao-Tong Ding, Lin Yan, Shi-Ru Jia, Yu-Jie Dai, Yan-Yan Xie e Cheng Zhong. "Identification of Quorum-Sensing Molecules of N-Acyl-Homoserine Lactone in Gluconacetobacter Strains by Liquid Chromatography-Tandem Mass Spectrometry". Molecules 24, n. 15 (24 luglio 2019): 2694. http://dx.doi.org/10.3390/molecules24152694.

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Abstract (sommario):

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using N-acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. N-acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, Gluconacetobacter xylinus CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. Gluconacetobacter sp. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.

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41

Paço, Ana, Teresa Brás, Jacqueline O. Santos, Paula Sampaio, Andreia C. Gomes e Maria F. Duarte. "Anti-Inflammatory and Immunoregulatory Action of Sesquiterpene Lactones". Molecules 27, n. 3 (8 febbraio 2022): 1142. http://dx.doi.org/10.3390/molecules27031142.

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Abstract (sommario):

Sesquiterpene lactones (SL), characterized by their high prevalence in the Asteraceae family, are one of the major groups of secondary metabolites found in plants. Researchers from distinct research fields, including pharmacology, medicine, and agriculture, are interested in their biological potential. With new SL discovered in the last years, new biological activities have been tested, different action mechanisms (synergistic and/or antagonistic effects), as well as molecular structure–activity relationships described. The review identifies the main sesquiterpene lactones with interconnections between immune responses and anti-inflammatory actions, within different cellular models as well in in vivo studies. Bioaccessibility and bioavailability, as well as molecular structure–activity relationships are addressed. Additionally, plant metabolic engineering, and the impact of sesquiterpene lactone extraction methodologies are presented, with the perspective of biological activity enhancement. Sesquiterpene lactones derivatives are also addressed. This review summarizes the current knowledge regarding the therapeutic potential of sesquiterpene lactones within immune and inflammatory activities, highlighting trends and opportunities for their pharmaceutical/clinical use.

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42

Verdaguer, Xavier, Marcus C. Hansen, Scott C. Berk e Stephen L. Buchwald. "Titanocene-Catalyzed Reduction of Lactones to Lactols". Journal of Organic Chemistry 62, n. 24 (novembre 1997): 8522–28. http://dx.doi.org/10.1021/jo971560s.

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43

Ng, Filomena S. W., Daniel M. Wright e Stephen Y. K. Seah. "Characterization of a Phosphotriesterase-Like Lactonase fromSulfolobus solfataricusand Its Immobilization for Disruption of Quorum Sensing". Applied and Environmental Microbiology 77, n. 4 (23 dicembre 2010): 1181–86. http://dx.doi.org/10.1128/aem.01642-10.

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Abstract (sommario):

ABSTRACTSsoPox, a bifunctional enzyme with organophosphate hydrolase andN-acyl homoserine lactonase activities from the hyperthermophilic archaeonSulfolobus solfataricus, was overexpressed and purified from recombinantPseudomonas putidaKT2440 with a yield of 9.4 mg of protein per liter of culture. The enzyme has a preference forN-acyl homoserine lactones (AHLs) with acyl chain lengths of at least 8 carbon atoms, mainly due to lowerKmvalues for these substrates. The highest specificity constant obtained was forN-3-oxo-decanoyl homoserine lactone (kcat/Km= 5.5 × 103M−1·s−1), but SsoPox can also degradeN-butyryl homoserine lactone (C4-HSL) andN-oxo-dodecanoyl homoserine lactone (oxo-C12-HSL), which are important for quorum sensing in ourPseudomonas aeruginosamodel system. WhenP. aeruginosaPAO1 cultures were grown in the presence of SsoPox-immobilized membranes, the production of C4-HSL- and oxo-C12-HSL-regulated virulence factors, elastase, protease, and pyocyanin were significantly reduced. This is the first demonstration that immobilized quorum-quenching enzymes can be used to attenuate the production of virulence factors controlled by quorum-sensing signals.

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44

Adekenov, S. M., e G. A. Atazhanova. "Heteroatom-Containing Natural Sesquiterpene Lactones and Methods for their Obtaining". Eurasian Chemico-Technological Journal 15, n. 3 (13 maggio 2013): 195. http://dx.doi.org/10.18321/ectj223.

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Abstract (sommario):

This review shows the data about isolated heteroatom-containing sesquiterpene lactones from various genera of Asteraceae family, natural occurence, isolation methods and their biological activity. Chlorinecontaining sesquiterpene lactones were isolated from genera of Artemisia L., Achillea L., Acroptilon Cass, Centaurea L., Chartolepis Cass, Eupatorium L., Jurinea Cass, Rhaponticum Adams, Saussurea DC. The greatest quantity of chlorine-containing sesquiterpene lactones were isolated from Centaurea genus. 25 new sesquiterpene lactones with chlorine atom in molecule were isolated and characterized. The sesquiterpene lactones, which in their structure contained a sulphur atom as a component of various alkoxyl-, thiohydroxygroups and acid residues, were isolated from genera of Eupatorium L., Petasites Mill, Helenium L., Acritopappus R.M. King and H. Rob., Arctium L., Saussurea DC. Nitrogen atom in the structure of natural sesquiterpene lactones is present in the form of amino groups as a part of ester groups as well as amino acids as Michael adducts. Nitrogen-containing sesquiterpene lactones were isolated from Acanthospermum Schrank, Saussurea DC. Isolated heteroatom-containing sesquiterpene lactones possess bactericidal, antifungal, cytotoxic, antiviral, virucidal, antiulcer and others activities. Another method for obtaining heteroatom-containing sesquiterpene lactones is a directed synthesis of chlorine-, fluorine-, bromine-, sulphur- and nitrogen-containing sesquiterpene lactones. On the basis of sesquiterpene lactone artemisinin known as an effective antimalarial preparation, we synthesized over 200 derivatives, among which fluorine-, chlorine-, bromine-, nitrogen-, sulphur- and azide-containing derivatives of artemisinin were obtained.

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45

Merbouh, Nabyl, Simon Cassegrain e Wen Zhou. "4-Phenylnaphtho[2,3-c]furan-1(3H)-one, 9-Phenylnaphtho[2,3-c]furan-1(3H)-one and 3a,4-Dihydro-9-phenylnaphtho[2,3-c]furan-1(3H)-one Crystal Structures". Crystals 11, n. 8 (23 luglio 2021): 857. http://dx.doi.org/10.3390/cryst11080857.

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Abstract (sommario):

The crystal structures are reported for two unsubstituted arylnaphthalene lactones, 4-phenylnaphtho[2,3-c]furan-1(3H)-one (2), 9-phenylnaphtho[2,3-c]furan-1(3H)-one (3) and a non-aromatic dihydro arylnaphthene lactone, 3a,4-dihydro-9-phenylnaphtho[2,3-c]furan-1(3H)-one (5). There are only minor differences in the geometrical parameters of these structures. However, in certain cases, both isomers of arylnaphthalene lactones (termed Type I and Type II) were found in the same asymmetric unit cell.

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46

Grant, PK, LR Hanton, GP Lynch, J. Simpson e GC Slim. "Assignment of Local Conformation in Medium-Ring Unsaturated Lactones Derived From Labda-8(17),14-dien-13-Ol (Manool)". Australian Journal of Chemistry 44, n. 7 (1991): 897. http://dx.doi.org/10.1071/ch9910897.

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Abstract (sommario):

The unsaturated lactone (2) derived from manool (1) has a particularly rigid 10-membered ring which gives rise to high asymmetric induction in epoxidation with m-chloroperoxybenzoic acid. The corresponding 11-membered lactone (14) shows greater flexibility. The conformations of lactone (2) and epoxy lactones (12) and (13) have been determined by X-ray diffraction studies.

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47

Dor, Shlomit, Dov Prusky e Livnat Afriat-Jurnou. "Bacterial Quorum-Quenching Lactonase Hydrolyzes Fungal Mycotoxin and Reduces Pathogenicity of Penicillium expansum—Suggesting a Mechanism of Bacterial Antagonism". Journal of Fungi 7, n. 10 (2 ottobre 2021): 826. http://dx.doi.org/10.3390/jof7100826.

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Abstract (sommario):

Penicillium expansum is a necrotrophic wound fungal pathogen that secrets virulence factors to kill host cells including cell wall degrading enzymes (CWDEs), proteases, and mycotoxins such as patulin. During the interaction between P. expansum and its fruit host, these virulence factors are strictly modulated by intrinsic regulators and extrinsic environmental factors. In recent years, there has been a rapid increase in research on the molecular mechanisms of pathogenicity in P. expansum; however, less is known regarding the bacteria–fungal communication in the fruit environment that may affect pathogenicity. Many bacterial species use quorum-sensing (QS), a population density-dependent regulatory mechanism, to modulate the secretion of quorum-sensing signaling molecules (QSMs) as a method to control pathogenicity. N-acyl homoserine lactones (AHLs) are Gram-negative QSMs. Therefore, QS is considered an antivirulence target, and enzymes degrading these QSMs, named quorum-quenching enzymes, have potential antimicrobial properties. Here, we demonstrate that a bacterial AHL lactonase can also efficiently degrade a fungal mycotoxin. The mycotoxin is a lactone, patulin secreted by fungi such as P. expansum. The bacterial lactonase hydrolyzed patulin at high catalytic efficiency, with a kcat value of 0.724 ± 0.077 s−1 and KM value of 116 ± 33.98 μM. The calculated specific activity (kcat/KM) showed a value of 6.21 × 103 s−1M−1. While the incubation of P. expansum spores with the purified lactonase did not inhibit spore germination, it inhibited colonization by the pathogen in apples. Furthermore, adding the purified enzyme to P. expansum culture before infecting apples resulted in reduced expression of genes involved in patulin biosynthesis and fungal cell wall biosynthesis. Some AHL-secreting bacteria also express AHL lactonase. Here, phylogenetic and structural analysis was used to identify putative lactonase in P. expansum. Furthermore, following recombinant expression and purification of the newly identified fungal enzyme, its activity with patulin was verified. These results indicate a possible role for patulin and lactonases in inter-kingdom communication between fungi and bacteria involved in fungal colonization and antagonism and suggest that QQ lactonases can be used as potential antifungal post-harvest treatment.

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48

Di Marzo, V., G. Cimino, A. Crispino, C. Minardi, G. Sodano e A. Spinella. "A novel multifunctional metabolic pathway in a marine mollusc leads to unprecedented prostaglandin derivatives (prostaglandin 1,15-lactones)". Biochemical Journal 273, n. 3 (1 febbraio 1991): 593–600. http://dx.doi.org/10.1042/bj2730593.

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Abstract (sommario):

The discovery of high levels of prostaglandin (PG) 1,15-lactones of both the E and F series and their co-existence with PGs has been recently described in the opisthobranch mollusc Tethys fimbria. The present study was undertaken in order to investigate the biosynthesis of these novel natural PG derivatives in vivo using radiolabelled precursors, and to gain a preliminary understanding of their biological role. PGE2 1,15-lactone was shown to be produced from both PGE2 and PGF2 alpha in the mollusc mantle and appeared to be quickly transferred to the mollusc dorsal appendices (cerata). The detachment of the latter during the typical defence behaviour of T. fimbria was accompanied by the conversion of PGE2 and PGE3 1,15-lactones back to the corresponding PGs. Both PGE2 and PGE2 1,15-lactone were also shown to be biosynthesized from arachidonic acid. Lactones of the F series were present as 11-acetyl derivatives in T. fimbria mantle and as 9- and 11-fatty acyl esters in the mollusc egg-mass and reproductive gland, and their biosynthesis from PGF2 alpha was demonstrated in all of these tissues. A multiple biological role of PG 1,15-lactones in T. fimbria defensive behaviour, smooth muscle contraction and egg production/fertilization control is hypothesized. The high amounts of PG derivatives found in T. fimbria and the biosynthetic studies described herein indicate that this marine mollusc may be a useful model for future studies on PG biosynthesis.

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49

Bergonzi, Celine, Michael Schwab e Mikael Elias. "The quorum-quenching lactonase fromGeobacillus caldoxylosilyticus: purification, characterization, crystallization and crystallographic analysis". Acta Crystallographica Section F Structural Biology Communications 72, n. 9 (9 agosto 2016): 681–86. http://dx.doi.org/10.1107/s2053230x16011821.

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Abstract (sommario):

Lactonases are enzymes that are capable of hydrolyzing various lactones such as aliphatic lactones or acyl-homoserine lactones (AHLs), with the latter being used as chemical signaling molecules by numerous Gram-negative bacteria. Lactonases therefore have the ability to quench the chemical communication, also known as quorum sensing, of numerous bacteria, and in particular to inhibit behaviors that are regulated by this system, such as the expression of virulence factors or the production of biofilms. A novel representative from the metallo-β-lactamase superfamily, dubbed GcL, was isolated from the thermophilic bacteriumGeobacillus caldoxylosilyticus. Because of its thermophilic origin, GcL may constitute an interesting candidate for the development of biocontrol agents. Here, we show that GcL is a thermostable enzyme with a half-life at 75°C of 152.5 ± 10 min. Remarkably, it is also shown that GcL is among the most active lactonases characterized to date, with catalytic efficiencies (kcat/Km) against AHLs of greater than 106 M−1 s−1. The structure of GcL is expected to shed light on the catalytic mechanism of the enzyme and the molecular determinants for the substrate specificity in this class of lactonases. Here, the expression, purification, characterization, crystallization and X-ray diffraction data collection to 1.6 Å resolution of GcL are reported.

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50

Aslanli, Aysel, Ilya Lyagin e Elena Efremenko. "Novel approach to quorum quenching: rational design of antibacterials in combination with hexahistidine-tagged organophosphorus hydrolase". Biological Chemistry 399, n. 8 (26 luglio 2018): 869–79. http://dx.doi.org/10.1515/hsz-2018-0162.

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Abstract (sommario):

Abstract N-acyl homoserine lactones (AHLs) are quorum sensing (QS) signal molecules used by most Gram-negative pathogenic bacteria. In this article the lactonase activity of the preparations based on hexahistidine-tagged organophosphorus hydrolase (His6-OPH) towards AHLs was studied. Initially, three of the most interesting β-lactam antibiotics were selected from seven that were trialed during molecular docking to His6-OPH. Combinations of antibiotics (meropenem, imipenem, ceftriaxone) and His6-OPH taken in the native form or in the form of non-covalent enzyme-polyelectrolyte complexes (EPCs) with poly(glutamic acid) or poly(aspartic acid) were obtained and investigated. The lactonase activity of the preparations was investigated under different physical-chemical conditions in the hydrolysis of AHLs [N-butyryl-D,L-homoserine lactone, N-(3-oxooctanoyl)-D,L-homoserine lactone, N-(3-oxododecanoyl)-L-homoserine lactone]. An increased efficiency of catalytic action and stability of the lactonase activity of His6-OPH was shown for its complexes with antibiotics and was confirmed in trials with bacterial strains. The broadening of the catalytic action of the enzyme against AHLs was revealed in the presence of the meropenem. Results of molecular docking of AHLs to the surface of the His6-OPH dimer in the presence of antibiotics allowed proposing the mechanism of such interference based on a steric repulsion of the carbon chain of hydrolyzed AHLs by the antibiotics bounded to the enzyme surface.

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