Bibliografie tematiche / Lactones

Letteratura scientifica selezionata sul tema "Lactones"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 7 luglio 2024

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Articoli di riviste sul tema "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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Abstract (sommario):
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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2

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 (sommario):
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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3

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 (sommario):
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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Abstract (sommario):
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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5

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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Abstract (sommario):
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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6

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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Abstract (sommario):
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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Abstract (sommario):
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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Abstract (sommario):
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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9

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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Abstract (sommario):
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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10

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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Abstract (sommario):
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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Più fonti

Tesi sul tema "Lactones"

1

Wheatley, Joseph R. "Lactones in synthesis". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337424.

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2

Shangula, Suha. "Effect of paraoxonase (PON1) on lactones and ROS induced DNA damage". Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/effect-of-paraoxonase-pon1-on-lactones-and-ros-induced-dna-damage(928ac761-7039-4f6f-9135-40a6f71b9465).html.

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Abstract (sommario):
Paraoxonase 1 (PON1) is an enzyme synthesised in the liver that is associated with High Density Lipoprotein (HDL) and increasingly with a number of human diseases, including cardiovascular disease and cancer. PON1 is (i) a lactonase, hydrolysing aliphatic and aromatic lactones, (ii) a phosphotriesterase, acting on certain organophosphates and (iii) a peroxidase that combats lipid oxidation. The aim of this study was to investigate the extent to which PON1 might impact on the levels of lactone-induced and oxidative DNA damage. Initially, the plasmid DNA (pDNA) nicking assay was used to show that of the 12 lactones and homocysteine (HC) examined, only alpha angelica lactone (AAL), Furanone (FUR) and HC caused DNA single strand breaks (SSB) under physiological conditions. Further studies indicated that AP sites were not involved suggesting that DNA-phosphotriesters were responsible. AAL-reacted pDNA bound the damage sensing protein, Atl1, and AAL, HC and HC thiolactone (HCTL) -reacted calf thymus DNA inhibited the activity of the DNA repair protein, MGMT, both indicating the presence of O6-alkylguanines in DNA, although this could not be confirmed using MALDI-ToF MS analyses of tryptic digests of MGMT incubated with lactone-reacted DNA. The inhibition of rPON1 by these lactones and HC was determined using paraoxon as a substrate and two groups were identified comprising lactones that caused reductions in PON1 activity of (i) ˃15% (e.g. HCTL, and AAL) and (ii) ˂10% (e.g. FUR, and HC). The pDNA nicking assay then showed that only AAL and FUR induced DNA single strand breaks. PON1 itself nicked pDNA, and bound to group 1 lactone-reacted pDNA by an unknown mechanism, both effects not previously reported, but, with the possible exception of AAL, did not increase the extent of plasmid nicking. The MTT, cell viability assay, indicated that all of the lactones with the exception of γ-BL (IC50 >12 mM) were to some degree toxic in HepG2 cells with AAL being the most toxic (IC50 1.0 ±0.03 mM). It was not possible to quantify PON1 activity in HepG2 cells and agents that are reported to change the expression levels of PON1 had no detectable impact on the toxicity of AAL, γ-VL, FUR or MBL, so any possible effect of PON1 could not be determined. The neutral Comet assay showed that AAL and HCTL generated the highest levels of DNA double strand breaks and DNA fragmentation in HepG2 cells, and that this effect was greatly enhanced for most of the lactones by the addition of rPON1. The impact of PON1 on oxidative stress was investigated using serum samples collected as part of a previous case-control study of lung cancer. Initially, an in-house developed ELISA assay to quantify 8-hydroxydeoxyguanosine (8-OHdG) levels had insufficient sensitivity and poor reproducibility. Hence 8OHdG levels were measured using kits along with PON1 levels and other serum parameters including HDL-C, LDL-C, TG and apoAI in serum from 112 patients with lung cancer and 249 patients without. No correlation was found between serum level of PON1 activity and level of 8-OHdG in patients with lung cancer, however a negative non-significant correlation was found between PON1 and 8-OHdG in control. The level of 8-OHdG was significantly higher in lung cancer patients than in controls and in the controls, the OGG1 wild type genotype correlated with reduced levels of 8-OHdG in serum. These studies showed that certain lactones, are toxic and DNA damaging and this can be increased by PON1, suggesting that any association between PON1 and human disease will be substrate dependent and may be PON1 genotype-dependent.
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3

Arasa, Bertomeu Mª Mercè. "Nous termoestables epoxídics modificats amb gamma-lactones i bis-gamma-lactones condensades". Doctoral thesis, Universitat Rovira i Virgili, 2009. http://hdl.handle.net/10803/9033.

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Abstract (sommario):
Aquest treball s'emmarca en el camp dels materials termoestables amb aplicacions en recobriments o encapsulants per microelectrònica i pretén l'obtenció de materials amb millor durabilitat i que després del temps d'ús puguin ser degradats i permetin la recuperació del material electrònic, el que constitueix una gran avantatja des del punt de vista mediambiental. L'estratègia escollida ha estat la copolimerització de diglicidilèter de bisfenol A (DGEBA) amb mono--lactones i bis--lactones utilitzant diversos triflats de terres rares i el BF3·MEA com iniciadors catiònics i varies amines terciàries com iniciadors aniònics. Aquesta estratègia permet la introducció de grups ester, tèrmica i químicament làbils i alhora reduir l'encongiment que es produeix durant el curat. La incorporació de cadenes alifàtiques, provinents de les lactones, entre punts d'entrecreuament augmenta la flexibilitat de la xarxa polimèrica i disminueix la fragilitat del material. La millora de les propietats mecàniques també va ser estudiada addicionant montmorillonites laminars.
This work focuses on the thermosetting materials area with applications in coatings or encapsulates for microelectronic devices and it seeks to obtain materials with better durability that after their working life, could be degraded and let the recuperation of the electronic material, which means a great advantage for the environment. The strategy followed has been the copolymerization of diglycidylether of bisphenol A (DGEBA) with mono--lactones and condensed bis--lactones using several rare earth triflates and BF3·MEA as cationic initiators and several tertiary amines as anionic iniciators. This strategy lets the introduction of ester linkages, thermal and chemically cleavable and at the same time the reduction of the shrinkage which is produced during the curing process. The incorporation of aliphatic chains, that come from lactones, between cross-linking points increases the flexibility of the polymeric network and decreases the fragility of the material. The improvement of the mechanical properties also was studied adding layered montmorillonites.
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4

Fairbanks, Antony J. "Sugar lactones in synthesis". Thesis, University of Oxford, 1993. http://ora.ox.ac.uk/objects/uuid:44329487-5d08-4df4-8baf-fc682d4bc9cc.

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Abstract (sommario):
This thesis describes the synthesis of some novel carbohydrate lactones and their uses as starting materials in (a) the syntheses of various polyfunctionalised cyclopentanes, via intramolecular aldol condensations, (b) the synthesis of 1-epihydantocidin, in which the crucial synthetic step involves a novel transformation induced by tetra-n-propylammonium perruthenate, and (c) the syntheses of various tetrahydrofurans and tetrahydropyrans. The syntheses of 3,4-O-isopropylidene and cyclohexylidene altrono and allono-1,5-lactones via Kiliani ascension of protected forms of D-ribose are described. The stereochemistry of the major reaction product, which was identified as 2,3-O-isopropylidene-D-altrono-l,5-lactone was confirmed by X-ray diffraction. Introduction of azide and iodide at C-2 is achieved via silyl protection of C-6 and formation of the 2-O-triflates. Nucleophilic displacement with azide or iodide produces mixtures of C-2 epimers. Desilylation is readily achieved by treatment with acetic acid to yield azido and iodo alcohols. Attempted oxidation of C-6 to an aldehyde functionality, in an attempt to effect cyclopentane formation via intramolecular aldol condensation of C-2 onto C-6 failed. Treatment of altrono and allono azido alcohols with tetrapropylammonium perruthenate unexpectedly results in the formation of a [2.2.2.] bicyclic hemiaminal, whose structure was confirmed by X-ray diffraction. Conversion of the amine functionality to a urea is effected by treatment with potassium cyanate. Cyclisation of the urea functionality onto the lactone carbonyl and subsequent deprotection effects the synthesis of 1-epihydantocidin. Investigations into acid catalysed epimerisation of the spiro centre in both hydantocidin and 1-epihydantocidin are described. Potassium carbonate induced ring contraction of 6-O-silyl altrono- and allono- 1,5-lactone-2-O-triflates yields tetrahydrofurans, the stereochemistry of which is confirmed by conversion to symmetric materials. Intramolecular Mitsunobu cyclisation of OH-2 onto C-6 of altrono-1,5-lactones effects tetrahydropyran formation. Inversion of C-5 of the known 3,4:5,6-di-O-ispropylidene-D-glycero-D-galacto-heptono- 1,5-lactone is described. Confirmation of product stereochemistry is achieved by conversion to 2,3-O-isopropylidene-L-altrono-1,5-lactone. Introduction of iodide and azide at C-2 is achieved via the formation of the 2-O-triflate. Selective deprotection of the 5,6 isopropylidene and subsequent periodate cleavage yields aldehydo lactones which undergo potassium fluoride induced intramolecular aldol cyclisation, to yield bicyclic [2.2.1.] azido and iodo carbocycles. Sodium azide induced intramolecular aldol cyclisation of 5-azido-5-deoxy-3,4-O-isopropylidene-L-galacturono-2,6-lactone, which produces two [2.2.1.] bicyclic azido carbocycles, is described. The second azido carbocycle, which is found to be the major reaction product, readily undergoes a retro aldol reaction, resulting in the formation of a third azido carbocycle, the structure of which was confirmed by X-ray diffraction. Investigations into the equilibration of these three bicyclic [2.2.1.] azido carbocycles under the reaction conditions employed to effect their formation are described. Various ring opening reactions of the second and third materials, and their uses in the syntheses of a novel amino pentol, two novel tetrahydroxy cyclopentane spirohydantoins and two novel cyclopentane amino acids are described. The structure of the asymmetric amino acid was confirmed by X-ray diffraction. Under basic reaction conditions retro aldol equilibration is seen to compete effectively with ring opening.
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5

Maughan, K. "Grignard reactions with lactones". Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356029.

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6

Mitchell, Helen Joy. "Stereocontrol with diphenylphosphinoyl lactones". Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/271942.

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7

Rogers, Paul S. "Sugar lactones in organic synthesis". Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425897.

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8

Simone, Michela A. "Studies on branched sugar lactones". Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497098.

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9

Toczek, Judy. "Synthetic studies on terpenoid lactones". Thesis, Brunel University, 1985. http://bura.brunel.ac.uk/handle/2438/7401.

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Abstract (sommario):
A novel stereoselective route has been developed to a vernolepin intermediate in nine steps from 2-phenylthiocyclopentenone. During this research, a regiospecific method for the alkylation of the Δ5,6 - tetrahydroindanone system has been achieved. In addition, the synthetic route demonstrates a means of differentiating between two carboxylic acid functions via a selective lactonisation. The first total ynthesis of boonein has also been completed, in 3% yield from cyclopentadiene. This route uses a chlorine atom to direct the stereo- and regiochemical outcome of most of these reaction.
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10

Dumeunier, Raphaël. "New methodologies towards lactones and methylene-lactones : application to the total synthesis of Polycavernoside A". Université catholique de Louvain, 2004. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-05242004-130732/.

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Methylene-butyrolactones are readily accessed by two methodologies based on a particular ene reaction. Both methodologies have been applied to the synthesis of the northern fragment of Polycavernoside. A reverse Julia reaction was used as the key step of a new methodology towards triene frameworks ; a mechanistic study revealed the unexpected role of triflic acid in the field of metal triflates catalysed acylation of alcohols, and a new tandem Brook rearrangement-allylation sequence was developed in the viewpoint of an improved total synthesis of Polycavernoside A.
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Libri sul tema "Lactones"

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Sülsen, Valeria Patricia, e Virginia Susana Martino, a cura di. Sesquiterpene Lactones. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4.

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Ogliaruso, Michael A. Synthesis of lactones and lactams. Chichester: Wiley, 1993.

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Janecki, Tomasz, a cura di. Natural Lactones and Lactams. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527666911.

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Vercruysse, J., e R. S. Rew, a cura di. Macrocyclic lactones in antiparasitic therapy. Wallingford: CABI, 2002. http://dx.doi.org/10.1079/9780851996172.0000.

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Toczek, Judy. Synthetic studies on terpenoid lactones. Uxbridge: Brunel University, 1985.

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J, Vercruysse, e Rew Robert S, a cura di. Macrocyclic lactones in antiparasitic therapy. Oxon, UK: CABI Pub., 2002.

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Ogliaruso, Michael A., e James F. Wolfe, a cura di. Synthesis of Lactones and Lactams (1993). Chichester, UK: John Wiley & Sons, Inc., 1993. http://dx.doi.org/10.1002/9780470772522.

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William, Hutchens T., Lönnerdal Bo 1938- e International Symposium on Lactoferrin: Interactions and Biological Functions (2nd : 1995 : Honolulu, Hawaii), a cura di. Lactoferrin: Interactions and biological functions. Totowa, N.J: Humana Press, 1997.

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Mcnaughton-Smith, Grant Andrew. Synthetic approaches to the ascidiatrienolides and other medium ring lactones. Norwich: University of East Anglia, 1993.

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Serkerov, Siradzhaddin Veli ogly. Terpenoidy i fenolproizvodnye rasteniĭ semeĭstv: Asteraceae i Apiaceae. Baku: CBS, 2005.

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Capitoli di libri sul tema "Lactones"

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Etienne, Y., e N. Fischer. "β-Lactones". In Chemistry of Heterocyclic Compounds: A Series Of Monographs, 729–884. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2008. http://dx.doi.org/10.1002/9780470239704.ch6.

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Sülsen, Valeria P., e Virginia S. Martino. "Overview". In Sesquiterpene Lactones, 3–17. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_1.

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Lombardo, María E., e Alcira Batlle. "Mode of Action on Trypanosoma and Leishmania spp." In Sesquiterpene Lactones, 223–40. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_10.

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Lozano, Esteban, Renata Spina, Patricia Barrera, Carlos Tonn e Miguel A. Sosa. "Contribution of Microscopy for Understanding the Mechanism of Action Against Trypanosomatids". In Sesquiterpene Lactones, 241–73. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_11.

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Castelli, María Victoria, e Silvia Noelí López. "Effects on Other Microorganisms". In Sesquiterpene Lactones, 275–301. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_12.

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Anesini, Claudia A., María Rosario Alonso e Renzo F. Martino. "Antiproliferative and Cytotoxic Activities". In Sesquiterpene Lactones, 303–23. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_13.

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Alonso, María Rosario, Claudia A. Anesini e Renzo F. Martino. "Anti-inflammatory Activity". In Sesquiterpene Lactones, 325–46. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_14.

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Schmidt, Thomas J. "Structure-Activity and Activity-Activity Relationships of Sesquiterpene Lactones". In Sesquiterpene Lactones, 349–71. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_15.

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Giberti, Gustavo C. "Ancient and Modern Concepts About the Asteraceae Taxonomy". In Sesquiterpene Lactones, 19–29. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_2.

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Alves, Mateus Feitosa, Luciana Scotti, Fernando Batista Da Costa e Marcus Tullius Scotti. "Chemotaxonomic Study of Sesquiterpene Lactones of Asteraceae: Classical and Modern Methods". In Sesquiterpene Lactones, 31–45. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-78274-4_3.

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Atti di convegni sul tema "Lactones"

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Levovnik, Bojan D., Aleksa P. Alargić, Miloš M. Svirčev e Goran I. Benedeković. "Building a 3D QSAR model with isopropylidene analogs of cytotoxic styryl-lactones". In 2nd International Conference on Chemo and Bioinformatics. Institute for Information Technologies, University of Kragujevac, 2023. http://dx.doi.org/10.46793/iccbi23.559l.

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Styryl-lactones are a class of natural products and related analogs that exhibit diverse biological activities, including anticancer, anti-inflammatory, and antimicrobial properties. Since these compounds are routinely obtained in our laboratory from their O-isopropylidene precursors, we envisioned the project to examine and compare their respective structures and in-vitro activities. This paper presents a basic 3D-QSAR steric model built on a small set of 11 selected O-isopropylidene and styryl-lactone (particularly [3.3.0]furofuranone) ligands and their in vitro activities against an MCF-7 cell line. It is part of a larger ongoing study that encompasses synthesis as well as in vitro and in silico testing of a growing library of natural products and their analogs, with the aim to determine their pharmacophores, molecular targets, and cellular mechanisms of action.
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Kovács, B., N. Szemerédi, N. Kúsz, T. Kiss, B. Csupor-Löffler, Y.-C. Tsai, G. Spengler e D. Csupor. "Antiproliferative sesquiterpene lactones from Ambrosia artemisiifolia L". In GA – 70th Annual Meeting 2022. Georg Thieme Verlag KG, 2022. http://dx.doi.org/10.1055/s-0042-1759242.

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Kovács, Balázs. "Sesquiterpene lactones of Ambrosia artemisiifolia". In Symposium of Young Researchers on Pharmacognosy. Szeged: Department of Pharmacognosy, University of Szeged, Faculty of Pharmacy, 2022. http://dx.doi.org/10.14232/syrpharmacognosy.2022.b1.

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MAKEMSON, JOHN, e ANATOL EBERHARD. "MEASUREMENT OF ACYL HOMOSERINE LACTONES WITH MASS SPECTROMETRY". In Proceedings of the 11th International Symposium. WORLD SCIENTIFIC, 2001. http://dx.doi.org/10.1142/9789812811158_0028.

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Reinhardt, JK, AM Klemd, O. Danton, M. De Mieri, M. Smieško, R. Huber, T. Bürgi, C. Gründemann e M. Hamburger. "Absolute configuration of sesquiterpene lactones with potent immunosuppressant activity". In 67th International Congress and Annual Meeting of the Society for Medicinal Plant and Natural Product Research (GA) in cooperation with the French Society of Pharmacognosy AFERP. © Georg Thieme Verlag KG, 2019. http://dx.doi.org/10.1055/s-0039-3399849.

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Ito, Hiroshi, Hoa D. Truong e Phil J. Brock. "Lactones in 193 nm resists: What do they do?" In SPIE Advanced Lithography, a cura di Clifford L. Henderson. SPIE, 2008. http://dx.doi.org/10.1117/12.772919.

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Cherepanov, Igor S., e Olga O. Botalova. "Lactones formation during monosaccharide's caramelization in ethanolic-aqueous solutions". In PROCEEDINGS OF INTERNATIONAL CONFERENCE ON RECENT TRENDS IN MECHANICAL AND MATERIALS ENGINEERING: ICRTMME 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0018037.

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Yoon, Kwang-Sub, Dong-Won Jung, Sook Lee, Sung-Ho Lee, Sang-Jun Choi, Sang-Gyun Woo e Joo-Tae Moon. "Novel 193-nm photoresist based on Olefin-containing lactones". In 26th Annual International Symposium on Microlithography, a cura di Francis M. Houlihan. SPIE, 2001. http://dx.doi.org/10.1117/12.436902.

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Reinhardt, JK, AM Klemd, M. De Mieri, M. Smiesko, T. Bürgi, C. Gründemann e M. Hamburger. "Absolute configuration of sesquiterpene lactones with potent immunosuppressive activity". In GA 2017 – Book of Abstracts. Georg Thieme Verlag KG, 2017. http://dx.doi.org/10.1055/s-0037-1608281.

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Fleisher, M., D. Jansone e L. Leite. "Nucleophilic Addition Reaction of Unsaturated Methyl Lactones with Pyridine Aldehydes". In The 1st International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 1997. http://dx.doi.org/10.3390/ecsoc-1-02001.

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Rapporti di organizzazioni sul tema "Lactones"

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Westwood, James H., Yaakov Tadmor e Hanan Eizenberg. Identifying the genes involved in host root perception by root parasitic weeds: Genetic and transcriptomic analysis of Orobanche hybrids differing in signal response specificity. United States Department of Agriculture, gennaio 2013. http://dx.doi.org/10.32747/2013.7598145.bard.

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Seeds of the root parasitic plants of the genus Orobanchegerminate specifically in response to host-derived germination signals, which enables parasites to detect and attack preferred hosts. The best characterized class of germination stimulants is the strigolactones (SL), although some species respond to sesquiterpene lactones such as dehydrocostuslactone (DCL). Despite great progress in characterizing the SL signaling system in plants, the mechanism(s) by which parasite species detect specific compounds remains poorly understood. The goal of our project was to identify and characterize the genes responsible for stimulant specificity in O. cernuaand O. cumana. These two species are closely related, but differ in host range, with O. cernuaparasitizingSolanaceous crops such as tomato (and responding to SLs), and O. cumanaspecifically parasitizing sunflower (and responding to DCL). We used a genetic approach based on O. cernuax O. cumanahybrids to associate germination response with genes. We found that these parasite species each have multiple copies of KAI2d genes, which function in SL perception. In O. cernua, the OrceKAI2d2 responds to SL stimulants and is most consistently associated with hybrid lines that respond to SLs. For O. cumana, an apparently linked block of KAI2d genes was associated with response to DCL in hybrid lines, but we found no strong evidence that any of the OrcuKAI2d genes specifically recognize the DCL stimulant. Remarkably, one O. cumanagene, OrcuKAI2d5, responds to certain SLs in a genetic complementation assay, even though hybrid lines containing this gene show fidelity to DCL. In summary, we have identified the SL receptor in O. cernua, but the DCL receptor in O. cumanaremains unknown. Our data point to involvement of additional genes and yet greater levels of complexity regulating germination specificity in Orobanche. BARD Report - Project 4616 Page 2 of 8
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Bazer, Fuller W., Arieh Gertler e Elisha Gootwine. Role of Placental Lactogen in Sheep. United States Department of Agriculture, gennaio 2001. http://dx.doi.org/10.32747/2001.7574339.bard.

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Central problems in sheep and dairy cattle production are reproductive failure due to embryonic/fetal mortality and low birth weights, especially in prolific breeds, and reduced milk yields which adversely affect neonatal survival and economy of production. The sheep placenta expresses lactogenic (ovine placental lactogen, oPL) and somatogenic (ovine placental growth hormone, oGH) hormones. Our research has focused on the biological roles of oPL and oGH in function of the uterine endometrium during gestation and the mammary gland during pregnancy and lactation. Major conclusions were that: ( 1 ) immunization of prepubertal ewes against oPL resulted in increased birth weights of their lambs and their milk production during lactation; (2) neither oPL nor oGH had an antiluteolytic effect on uterine endometrium to affect lifespan of the corpus luteum; (3) only sequential exposure of the progesterone stimulated uterus to oIFNt and oPL or oGH increased endometrial gland proliferation and secretory protein gene expression; (4) oPL signals through a homodimer of ovine prolactin receptor (PRL-R) and heterodimer of oPRL-R and growth hormone receptor (GH-R); (5) exogenous recombinant oPL and oGH stimulated mammogenesis and milk yield during lactation; and (6) mutation of oPL and oGH was used to define specific biological effects and a rational basis for design of a specific receptor agonists or antagonists. This project was very productive in elucidating basic biological effects of oPL and oGH on intracellular signal transduction pathways, uterine development and secretory function, as well as mammogenesis and lactogenesis. We determined that immunization of prepubertal ewes against roPL increased birth weights of their lambs, especially those born as twins and triplets, as well as enhanced lactational performance. These studies significantly extended our knowledge of uterine and fetal-placental physiology and provided a foundation for new strategies to enhance reproductive and lactation efficiency. Based on these results, the major achievements were: 1) creation of a practical and cost effective management tool for producers to increase reproductive performance, neonatal survival, and milk yield of ewes in commercial flocks; and 2) define, for the first time, biological effects of oPL on endometrial functions and gene expression by uterine gland epithelium.
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Spencer, Thomas E., Elisha Gootwine, Arieh Gertler e Fuller W. Bazer. Placental lactogen enhances production efficiency in sheep. United States Department of Agriculture, dicembre 2005. http://dx.doi.org/10.32747/2005.7586543.bard.

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The key objectives of this BARD project were to: (1) study long-term effects of immunization of prepubertal ewes against recombinant ovine placental lactogen (roPL) on subsequent birth weights of their lambs and their milk production; (2) optimize the anti-roPL immunization protocol using adjuvant preparations acceptable to producers and regulatory agencies; and (3) determine the physiological mechanism(s) whereby immunization against oPL increases fetal growth and development and mammogenesis. These objectives were based on key findings from a previous BARD project that: (a) immunization of ewes against roPL increased lamb birth weight and ewe milk production during lactation; (b) roPL and recombinant ovine growth hormone (roGH) increased the proliferation and differentiated function of endometrial glands that, in turn, would enhance uterine secretions necessary for fetal and placental growth; and (c) exogenous roPL and roGH stimulated mammogenesis and milk production during lactation. The BARD projects address central problems in sheep production, including reproductive failure due to embryonic/fetal mortality, low birth weight of lambs especially in prolific breeds, and reduced milk yields which affect neonatal survival. The sheep placenta secretes both lactogenic (oPL) and somatogenic (oGH) hormones. The receptors for those hormones are present in the fetus and placenta as well as maternal uterus, and mammary gland. Our research has focused on determining the biological role of these placental hormones in development and differentiation of the uterus during gestation and the mammary gland during pregnancy and lactation. Studies conducted in the current BARD project indicated that the effects of anti-roPL immunization were variable in ewes and that commercially available and widely acceptable adjuvant preparations were not effective to produce high anti-roPL titers in pre-pubertal ewes. In the non-prolific Rambouillet ewe in Texas and in the Awassi and the Assaf in Israel, anti-roPL immunization increased lamb birth weight; however, the magnitude of this effect and the inherent variability precluded our ability to determine the physiological mechanism of how the immunization increases fetal growth. Collectively, our findings suggest that anti-roPL immunization is not currently feasible as an easy and efficacious tool for the producer to increase flock reproductive and production efficiency. The variability in response of individual ewes to anti-roPL immunization likely includes modifying the recombinant hormone and the type of adjuvant used for the immunization. In particular, the oPL may need to be modified to ensure maximum antigenicity in a broad range of breed types. Nonetheless, the investigators continue to collaborate on identifying fundamental mechanisms that can be improved by genetics or management to enhance the efficiency of uteroplacental function and, in turn, fetal growth and development. High prolificacy is a desirable trait in intensive sheep production systems. One of the main limitations of using prolific breeds of sheep is that increased litter size is associated with low birth weights and increased mortality of lambs. Further, low birth weight is associated with an increased propensity for adult diseases and decreased production efficiency. Indeed, our recent studies find that the birth weights of lambs born in large litters can be improved by both genetics and management. Future cooperative research will continue to focus on reproductive efficiency of sheep that have broader implications for improving production efficiency in all types of ruminant livestock.
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Ulrich, Ricky L. Quorum Quenching: Enzymatic Disruption of N-Acylhomoserine Lactone-Mediated Bacterial Communication in Burkholderia thailandensis. Fort Belvoir, VA: Defense Technical Information Center, ottobre 2004. http://dx.doi.org/10.21236/ada428608.

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Joel, Daniel M., John C. Steffens e Alfred M. Mayer. Host-Elicited Germination and Mechanism of Penetration in Broomrape (Orobanche Spp.). United States Department of Agriculture, agosto 1993. http://dx.doi.org/10.32747/1993.7568107.bard.

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Orobanche is an important parasitic weed. For developing novel methods for its control, a thorough understanding of crucial stages of its development is needed. Therefore, the objectives of this project were characterization of Orobanche germination stimulants, analysis of mechanisms of haustorial penetration, and characterization and isolation of penetration enzymes. The first highly potent natural germination stimulant for Orobanche was isolated from sunflower and identified by high-field 1D (1H and 13C), 2D (1H-1H COSY, HMQC, HMBC)-NMR, GC.FT-IR, and GC.MS as costuslactone, a guaiane type sesquiterpene lactone that resembles strigol only in possessing a lactone moiety that is required for activity. The first direct in situ evidence for the enzymatic nature of the infection process of a parasitic angiosperm was established. Pectin deesterification and depletion of pectins in host cell walls were shown adjacent to haustorial cells. Pectin methyl esterase and polygalacturonase were immunocytochemically detected in intrusive cells and in adjacent host apoplast. Orobanche tissues contain inhibitors of PGase activity. PME and three PGases were isolated from Orobanche calli. PME was characterized and purified, and antibodies were prepared against it. This study presents novel findings regarding parasitism in Orobanche, which may help to open up new approaches for controlling broomrapes.
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Tachea, Firehiwot, Fabrice Masson, Chyi-Shin Chen, Qian He, Deepti Tanjore, Ning Sun e Todd Pray. Production of chemical intermediate triacetic acid lactone (TAL) via bacterial fermentation of deconstructed lignin: CRADA Final Report. Office of Scientific and Technical Information (OSTI), settembre 2017. http://dx.doi.org/10.2172/1393453.

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Ron, Eliora, e Eugene Eugene Nester. Global functional genomics of plant cell transformation by agrobacterium. United States Department of Agriculture, marzo 2009. http://dx.doi.org/10.32747/2009.7695860.bard.

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The aim of this study was to carry out a global functional genomics analysis of plant cell transformation by Agrobacterium in order to define and characterize the physiology of Agrobacterium in the acidic environment of a wounded plant. We planed to study the proteome and transcriptome of Agrobacterium in response to a change in pH, from 7.2 to 5.5 and identify genes and circuits directly involved in this change. Bacteria-plant interactions involve a large number of global regulatory systems, which are essential for protection against new stressful conditions. The interaction of bacteria with their hosts has been previously studied by genetic-physiological methods. We wanted to make use of the new capabilities to study these interactions on a global scale, using transcription analysis (transcriptomics, microarrays) and proteomics (2D gel electrophoresis and mass spectrometry). The results provided extensive data on the functional genomics under conditions that partially mimic plant infection and – in addition - revealed some surprising and significant data. Thus, we identified the genes whose expression is modulated when Agrobacterium is grown under the acidic conditions found in the rhizosphere (pH 5.5), an essential environmental factor in Agrobacterium – plant interactions essential for induction of the virulence program by plant signal molecules. Among the 45 genes whose expression was significantly elevated, of special interest is the two-component chromosomally encoded system, ChvG/I which is involved in regulating acid inducible genes. A second exciting system under acid and ChvG/Icontrol is a secretion system for proteins, T6SS, encoded by 14 genes which appears to be important for Rhizobium leguminosarum nodule formation and nitrogen fixation and for virulence of Agrobacterium. The proteome analysis revealed that gamma aminobutyric acid (GABA), a metabolite secreted by wounded plants, induces the synthesis of an Agrobacterium lactonase which degrades the quorum sensing signal, N-acyl homoserine lactone (AHL), resulting in attenuation of virulence. In addition, through a transcriptomic analysis of Agrobacterium growing at the pH of the rhizosphere (pH=5.5), we demonstrated that salicylic acid (SA) a well-studied plant signal molecule important in plant defense, attenuates Agrobacterium virulence in two distinct ways - by down regulating the synthesis of the virulence (vir) genes required for the processing and transfer of the T-DNA and by inducing the same lactonase, which in turn degrades the AHL. Thus, GABA and SA with different molecular structures, induce the expression of these same genes. The identification of genes whose expression is modulated by conditions that mimic plant infection, as well as the identification of regulatory molecules that help control the early stages of infection, advance our understanding of this complex bacterial-plant interaction and has immediate potential applications to modify it. We expect that the data generated by our research will be used to develop novel strategies for the control of crown gall disease. Moreover, these results will also provide the basis for future biotechnological approaches that will use genetic manipulations to improve bacterial-plant interactions, leading to more efficient DNA transfer to recalcitrant plants and robust symbiosis. These advances will, in turn, contribute to plant protection by introducing genes for resistance against other bacteria, pests and environmental stress.
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Spiers, Donald, Arieh Gertler, Harold Johnson e James Spain. An In Vitro and In Vivo Investigation of the Diverse Biological Activities of Bovine Placental Lactogen. United States Department of Agriculture, agosto 1993. http://dx.doi.org/10.32747/1993.7568087.bard.

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In order to understand the structure-function relationship of bovine placental lactogen (bPL) and initiate production of material for in vivo testing, 28 different bPL analogues were prepared by either truncation or site-directed mutagenesis. The effect of these mutations was determined by measuring binding capacity, ability to homodimerize extracellular domains (ECDs) of several lactogenic and somatogenic receptors, and by in vitro bioassays. Two analogues were prepared in large amounts for in vivo studies. These studies (a) identified the residues responsible for the somatogenic activity of bPL (K73, G133, T188) and for both lactogenic and somatogenic activity (N-terminus, K185, Y190); (b) allowed preparation of bPL analogues with selectively abolished or reduced somatogenic activity; and (c) provided a tool to understand the kinetic difference between lactogenic and somatogenic receptors. In vivo studies using rodent and dairy models showed that bovine growth hormone (bGH) is superior to bPL in stimulating growth and lactation. Likewise, bGH has greater somatogenic activity in different age groups and thermal environments. Initial studies of bPL analog T188 suggest that its lactogenic potential is superior to bGH. Effective experimental models have now been developed and tested for analysis of new bPL analogs.
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Wu, Xiaoqi, Maoxia Fan, Yaobo Pan e Dona Guo. Quality of Evidence Supporting the Effects of Ginkgo Terpene Lactone Preparations in Ischemic Stroke: An Overview of Systematic Reviews and Meta-Analyses. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, settembre 2022. http://dx.doi.org/10.37766/inplasy2022.9.0124.

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Review question / Objective: 2.2.1 Type of studies SRs/MAs of Randomized Controlled Trials (RCTs) of GTLP for IS in any language. 2.2.2 Type of Participants Included patients were diagnosed with IS according to international or national standards, regardless of race, age, gender, time of onset, and source of cases. 2.2.3 Type of Intervention The intervention method in the control group was routine treatment, and the intervention method in the intervention group was GTLP treatment or GTLP combined with the treatment of the control group. 2.2.4 Types of outcomes Conclusions at least need to include clinical efficacy analysis and National Institute of Health Stroke Scale (NIHSS). Condition being studied: Stroke is the second leading cause of death and third leading cause of disability globally.Among them, ischemic stroke (IS) accounts for 70% of all stroke types. It is a central nervous system disease caused by cerebral blood circulation disorder, ischemia and hypoxia .The incidence rate is high and increasing year by year, the age of onset is younger, the disability rate is high, and most patients have different degrees of limb motor dysfunction.In order to reduce the burden of stroke on the society and the patient's family, many articles proposed to strengthen the primary stroke prevention - behavior change and drug intervention.
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Bremel, Robert D., e Arieh Gertler. Effect of Bovine Placental Lactogen and other Placental Proteins on Growth and Differentiation of Cultured Bovine Mammary Cells. United States Department of Agriculture, settembre 1986. http://dx.doi.org/10.32747/1986.7566755.bard.

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