Academic literature on the topic 'Y-lactones'
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Journal articles on the topic "Y-lactones"
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Burger, B. V., and P. J. Pretorius. "Notes: Mammalian Pheromone Studies, VI. Compounds from the Preorbital Gland of the Blue Duiker, Cephalophus monticola." Zeitschrift für Naturforschung C 42, no. 11-12 (December 1, 1987): 1355–57. http://dx.doi.org/10.1515/znc-1987-11-1238.
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Forty five volatile compounds, mostly straight- and branched-chain alcohols and ketones, as well as derivatives of two of these alcohols, two y-lactones, an aromatic thiol ester and other simple aromatic compounds, have been identified in the preorbital secretion of the blue duiker, Cephalophus monticola.
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Yates, Edwin A., Bodo Philipp, Catherine Buckley, Steve Atkinson, Siri Ram Chhabra, R. Elizabeth Sockett, Morris Goldner, et al. "N-Acylhomoserine Lactones Undergo Lactonolysis in a pH-, Temperature-, and Acyl Chain Length-Dependent Manner during Growth of Yersinia pseudotuberculosis and Pseudomonas aeruginosa." Infection and Immunity 70, no. 10 (October 2002): 5635–46. http://dx.doi.org/10.1128/iai.70.10.5635-5646.2002.
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ABSTRACT In gram-negative bacterial pathogens, such as Pseudomonas aeruginosa and Yersinia pseudotuberculosis, cell-to-cell communication via the N-acylhomoserine lactone (AHL) signal molecules is involved in the cell population density-dependent control of genes associated with virulence. This phenomenon, termed quorum sensing, relies upon the accumulation of AHLs to a threshold concentration at which target structural genes are activated. By using biosensors capable of detecting a range of AHLs we observed that, in cultures of Y. pseudotuberculosis and P. aeruginosa, AHLs accumulate during the exponential phase but largely disappear during the stationary phase. When added to late-stationary-phase, cell-free culture supernatants of the respective pathogen, the major P. aeruginosa [N-butanoylhomoserine lactone (C4-HSL) and N-(3-oxododecanoyl)homoserine lactone (3-oxo-C12-HSL)] and Y. pseudotuberculosis [N-(3-oxohexanoyl)homoserine lactone (3-oxo-C6-HSL) and N-hexanoylhomoserine lactone (C6-HSL)] AHLs were inactivated. Short-acyl-chain compounds (e.g., C4-HSL) were turned over more extensively than long-chain molecules (e.g., 3-oxo-C12-HSL). Little AHL inactivation occurred with cell extracts, and no evidence for inactivation by specific enzymes was apparent. This AHL turnover was discovered to be due to pH-dependent lactonolysis. By acidifying the growth media to pH 2.0, lactonolysis could be reversed. By using carbon-13 nuclear magnetic resonance spectroscopy, we found that the ring opening of homoserine lactone (HSL), N-propionyl HSL (C3-HSL), and C4-HSL increased as pH increased but diminished as the N-acyl chain was lengthened. At low pH levels, the lactone rings closed but not via a simple reversal of the ring opening reaction mechanism. Ring opening of C4-HSL, C6-HSL, 3-oxo-C6-HSL, and N-octanoylhomoserine lactone (C8-HSL), as determined by the reduction of pH in aqueous solutions with time, was also less rapid for AHLs with more electron-donating longer side chains. Raising the temperature from 22 to 37°C increased the rate of ring opening. Taken together, these data show that (i) to be functional under physiological conditions in mammalian tissue fluids, AHLs require an N-acyl side chain of at least four carbons in length and (ii) that the longer the acyl side chain the more stable the AHL signal molecule.
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Loboiko, Yu V., Ye O. Barylo, and B. S. Barylo. "Assessment of macrocyclic lacton group products for ectoparasitosis of carp." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 22, no. 98 (August 22, 2020): 16–21. http://dx.doi.org/10.32718/nvlvet9803.
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The material for the study were Lubin carp of one year old spontaneously invaded by the ectoparasites Lernaea cyprinacea and Dactylogyrus vastator. For the experiment we used drugs: "Brovermectin-granulate" (development of “BFP” serial production; 1 g of the preparation contains: active substance (ADR) ivermectin – 3.5 mg; tocopherol acetate (20 mg) and Emamectin benzoate (manufactured by King Quenson Industry Group; 1 g of preparation contains ADR emamectin benzoate (50 mg). Analyzing morphological, biochemical and immunological parameters of blood and organs of fish, it is possible to state that the fact that the anti-parasitic drugs “Brovermectin granulate” and “Emamectin benzoate” has a pronounced antiparasitic effect, normalizing the homeostasis of the body. The results obtained showed significant fluctuations in the number neutrophils, eosinophils and lymphocytes. In ectoparasites infested of fishes used for macrocyclic lactones, y leukocyte formula sharply increases the percentage of rod-shaped neutrophils and at the same time decreases the proportion of lymphocytes. At the same time, there is an increase in the number of eosinophils that perform the function of protecting the body of fish from parasites. Eosinophilia, as in the higher vertebrates, is one of objective indicators of allergy (sensitization) of the body, nature the course of inflammatory processes. The results obtained indicate a decrease in the production of total T-lymphocytes are cells that play a key role in the immune system protection in the body of carp for damage by ectoparasites. In analyzing the above data, attention is drawn to the lower functional the activity of the blood T-lymphocyte system in ectoparasites infested with fish, than those given antiparasitic drugs. From this it follows that the ability of the blood lymphocytes of the fish to which the drugs from the group were given of macrocyclic lactones, before pathogen binding and production of antigens the antibodies that neutralize them are much higher than the fish affected ectoparasites. The immune system in fish provides self-regulation through direct contact of cells (macrophages, neutrophils, cytotoxic T-lymphocytes) as well as due to humoral factors (lysozyme, complement). The use of drugs from the group of macrocyclic lactones promotes the release of infested fish from ectoparasites with the following normalization of their life, increase of immune status and resistance.
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Gutenberger, Guido, Siegfried Blechert, and Eberhard Steckhan. "ChemInform Abstract: α-Cyano-y-lactones by Photoinduced Electron Transfer-Catalyzed Oxidation of α-Hydroxyalkylsilanes in the Presence of α-Cyano Acrylates." ChemInform 31, no. 17 (June 8, 2010): no. http://dx.doi.org/10.1002/chin.200017109.
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Dyszel, Jessica L., Jenee N. Smith, Darren E. Lucas, Jitesh A. Soares, Matthew C. Swearingen, Mathew A. Vross, Glenn M. Young, and Brian M. M. Ahmer. "Salmonella enterica Serovar Typhimurium Can Detect Acyl Homoserine Lactone Production by Yersinia enterocolitica in Mice." Journal of Bacteriology 192, no. 1 (October 9, 2009): 29–37. http://dx.doi.org/10.1128/jb.01139-09.
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ABSTRACT LuxR-type transcription factors detect acyl homoserine lactones (AHLs) and are typically used by bacteria to determine the population density of their own species. Escherichia coli and Salmonella enterica serovar Typhimurium cannot synthesize AHLs but can detect the AHLs produced by other bacterial species using the LuxR homolog, SdiA. Previously we determined that S. Typhimurium did not detect AHLs during transit through the gastrointestinal tract of a guinea pig, a rabbit, a cow, 5 mice, 6 pigs, or 12 chickens. However, SdiA was activated during transit through turtles colonized by Aeromonas hydrophila, leading to the hypothesis that SdiA is used for detecting the AHL production of other pathogens. In this report, we determined that SdiA is activated during the transit of S. Typhimurium through mice infected with the AHL-producing pathogen Yersinia enterocolitica. SdiA is not activated during transit through mice infected with a yenI mutant of Y. enterocolitica that cannot synthesize AHLs. However, activation of SdiA did not confer a fitness advantage in Yersinia-infected mice. We hypothesized that this is due to infrequent or short interactions between S. Typhimurium and Y. enterocolitica or that the SdiA regulon members do not function in mice. To test these hypotheses, we constructed an S. Typhimurium strain that synthesizes AHLs to mimic a constant interaction with Y. enterocolitica. In this background, sdiA + S. Typhimurium rapidly outcompetes the sdiA mutant in mice. All known members of the sdiA regulon are required for this phenotype. Thus, all members of the sdiA regulon are functional in mice.
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da Silva, Cristiane França, Denise da Gama Jaen Batista, Julianna Siciliano De Araújo, Marcos Meuser Batista, Jessica Lionel, Elen Mello de Souza, Erica Ripoll Hammer, et al. "Activities of Psilostachyin A and Cynaropicrin against Trypanosoma cruziIn VitroandIn Vivo." Antimicrobial Agents and Chemotherapy 57, no. 11 (August 12, 2013): 5307–14. http://dx.doi.org/10.1128/aac.00595-13.
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ABSTRACTIn vitroandin vivoactivities againstTrypanosoma cruziwere evaluated for two sesquiterpene lactones: psilostachyin A and cynaropicrin. Cynaropicrin had previously been shown to potently inhibit African trypanosomesin vivo, and psilostachyin A had been reported to showin vivoeffects againstT. cruzi, albeit in another test design.In vitrodata showed that cynaropicrin was more effective than psilostachyin A. Ultrastructural alterations induced by cynaropicrin included shedding events, detachment of large portions of the plasma membrane, and vesicular bodies and large vacuoles containing membranous structures, suggestive of parasite autophagy. Acute toxicity studies showed that one of two mice died at a cynaropicrin dose of 400 mg/kg of body weight given intraperitoneally (i.p.). Although no major plasma biochemical alterations could be detected, histopathology demonstrated that the liver was the most affected organ in cynaropicrin-treated animals. Although cynaropicrin was as effective as benznidazole against trypomastigotesin vitro, the treatment (once or twice a day) ofT. cruzi-infected mice (up to 50 mg/kg/day cynaropicrin) did not suppress parasitemia or protect against mortality induced by the Y and Colombiana strains. Psilostachyin A (0.5 to 50 mg/kg/day given once a day) was not effective in the acute model ofT. cruziinfection (Y strain), reaching 100% animal mortality. Our data demonstrate that although it is very promising against African trypanosomes, cynaropicrin does not show efficacy compared to benznidazole in acute mouse models ofT. cruziinfection.
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Habyarimana, Fabien, Matthew C. Swearingen, Glenn M. Young, Stephanie Seveau, and Brian M. M. Ahmer. "Yersinia enterocolitica Inhibits Salmonella enterica Serovar Typhimurium and Listeria monocytogenes Cellular Uptake." Infection and Immunity 82, no. 1 (October 14, 2013): 174–83. http://dx.doi.org/10.1128/iai.00984-13.
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ABSTRACTYersinia enterocoliticabiovar 1B employs two type three secretion systems (T3SS), Ysa and Ysc, which inject effector proteins into macrophages to prevent phagocytosis. Conversely,Salmonella entericaserovar Typhimurium uses a T3SS encoded bySalmonellapathogenicity island 1 (SPI1) to actively invade cells that are normally nonphagocytic and a second T3SS encoded by SPI2 to survive within macrophages. Given the distinctly different outcomes that occur with regard to host cell uptake ofS. Typhimurium andY. enterocolitica, we investigated how each pathogen influences the internalization outcome of the other.Y. enterocoliticareducesS. Typhimurium invasion of HeLa and Caco-2 cells to a level similar to that observed using anS. Typhimurium SPI1 mutant alone. However,Y. enterocoliticahad no effect onS. Typhimurium uptake by J774.1 or RAW264.7 macrophage-like cells.Y. enterocoliticawas also able to inhibit the invasion of epithelial and macrophage-like cells byListeria monocytogenes.Y. enterocoliticamutants lacking either the Ysa or Ysc T3SS were partially defective, while double mutants were completely defective, in blockingS. Typhimurium uptake by epithelial cells.S. Typhimurium encodes a LuxR homolog, SdiA, which detectsN-acylhomoserine lactones (AHLs) produced byY. enterocoliticaand upregulates the expression of an invasin (Rck) and a putative T3SS effector (SrgE). Two different methods of constitutively activating theS. Typhimurium SdiA regulon failed to reverse the uptake blockade imposed byY. enterocolitica.
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Rossini, Carmen, and Rodolfo Ungerfeld. "Chemical profile of the cutaneous gland secretions from male pampas deer ( Ozotoceros bezoarticus )." Journal of Mammalogy 97, no. 1 (October 28, 2015): 167–78. http://dx.doi.org/10.1093/jmammal/gyv167.
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Abstract Various cutaneous glands have been identified as sources of chemical signals that mediate many social interactions in deer. The pampas deer, a species considered near threatened, inhabits grasslands of South America. In this work, the chemical compositions from preorbital, tarsal, and digital gland secretions of semi-captive males were characterized by gas chromatography–mass spectrometry. The composition of these secretions showed a great complexity, with 143 compounds detected. Hierarchical cluster and principal component analyses show no relation to age or secretion type. Five compound classes (esters, fatty alcohols, lactones, sterols, and sulphuretted) differed with glands. The chemical complexity of the secretions, the individual differences in the whole compounds composition, and the absence of clustering by age lead to the hypothesis that these secretions may encode at once for individual information and for social status information. Varias glándulas cutáneas han sido identificadas como productoras de señales químicas que median interacciones sociales en losciervos. El venado de las pampas es una especie considerada casi amenazada que habita los pastizales de Sudamérica. En este trabajo se caracterizó la composición química de las secreciones de las glándulas preorbital, tarsal e interdigital de machos por cromatografía de gases-espectrometría de masas. Estas secreciones mostraron una gran complejidad en su composición, con 143 compuestos detectados. No se observó ninguna agrupación de compuestos relacionada con la edad o el tipo de secreción. Cinco clases de compuestos (ésteres, alcoholes grasos, lactonas, esteroles, y compuestos azufrados) difirieron de acuerdo al origen glandular. La complejidad química de las secreciones, las diferencias individuales en dicha composición, y la ausencia de agrupamiento por edad, llevan a postular la hipótesis de que estas secreciones pueden codificar a la vez tanto información individual como del estado social.
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Tomova, Teodora, Nina Doncheva, Anita Mihaylova, Ilia Kostadinov, Lyudmil Peychev, and Mariana Argirova. "An experimental study on phytochemical composition and memory enhancing effect of Ginkgo biloba seed extract." Folia Medica 63, no. 2 (April 30, 2021): 203–12. http://dx.doi.org/10.3897/folmed.63.e53060.
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Introduction: The Ginkgo biloba L. tree is considered as one of the oldest species on Earth. It is known as a “living fossil” dating back approximately 200 million years. Both the leaves and seeds of this tree have been used for millennia in traditional Chinese medicine. Aim: To study the phytochemical profile of Gingko biloba seed extract (GBSE) and its memory enhancing effects. Materials and methods: Liquid chromatography with mass detection (LC-MS) was performed for phytochemical analyses of the extracts. For the in vivo experiments, male Wistar rats were divided randomly into 5 groups (n=8): saline; piracetam; GBSE 50; 100, and 200 mg/kg b.w. Y-maze, T-maze, step-down passive avoidance and novel object recognition test (NORT) were performed. The observed parameters were: percentage of spontaneous alternations (% SA), working memory index, latency of reaction and recognition index, respectively. Statistical analysis was done using SPSS 19. Results: LC-MS analysis showed the presence of the flavonoids quercetin, kaempferol and isorhamnetin (as aglycones), the ginkgolides A, B, C, J, and bilobalide. In Y-maze task, the groups treated with 50 and 100 mg/kg of GBSE significantly increased the % SA during the memory test compared to saline (p<0.05). In T-maze test, the three experimental groups with GBSE significantly increased the working memory index in comparison with that of the control group (p<0.05). In step-down test, the animals receiving 100 mg/kg b.w. GBSE, notably increased the latency during both retention tests (p<0.05 and p<0.01, respectively). In NORT, only the animals with the middle dose of GBSE ameliorated the recognition index when compared to saline (p<0.05). Conclusions: GBSE enhances spatial working memory, recognition memory, and short- and long-term recall in naïve rats due to the synergic effects of detected flavonoids and terpene lactones on brain functions. The brain structures involved are probably the hippocampus and prefrontal cortex.
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Echavarria, Ana, Haydelba D'Armas Regnault, Nubia Lisbeth, Lisbeth Matute, Carmita Jaramillo, Luisa Rojas de Astudillo, and Ricardo Benitez. "Evaluación de la capacidad antioxidante y metabolitos secundarios de extractos de dieciséis plantas medicinales / Evaluation of antioxidant capacity and secondary metabolites of sixteen medicinal plants extracts." Ciencia Unemi 9, no. 20 (December 20, 2016): 29. http://dx.doi.org/10.29076/issn.2528-7737vol9iss20.2016pp29-35p.
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El presente estudio evaluó la capacidad antioxidante de los extractos de dieciséis plantas medicinales: escoba amarga (Parthenium hysterophons), ajenjo (Artemisia absinthium), guarumo (t), chaya (Cnidoscolus chayamansa), borraja (Borago officinalis), balsa (Ochroma sp.), linaza (Linum usitatissimum), hierba Luisa (Cymbopogon citratus), toronjil (Melissa officinalis), buganvilla (Bougainvillea spectabilis), alcachofa (Cynara scolymus), guaviduca (Piper carpunya), altamisa (Ambrosia cumanensis), diente de león (Taxacum officinales), buscapina (Parietaria officinalis) y moringa (Moringa oleifera). Para ello, se usó el método DPPH (radical 1,1-difenil-2-picrilhidrazil); además, se realizaron ensayos de reconocimiento de metabolitos secundarios a fin de obtener los primeros indicios de compuestos de interés fitoquímico. La actividad captadora de radicales libres de los extractos se expresó como valor de IC50 (μg/mL) (cantidad necesaria para inhibir la formación de radicales DPPH en un 50%). El valor bajo de IC50 refleja mejor acción eliminadora de radicales libres. Aunque la mayoría de las muestras evaluadas mostraron buena capacidad antioxidante con este método (DPPH), los ensayos de los extractos hidro-alcohólicos demuestran que la alcachofa (IC50 9,89 μg/mL), moringa (IC50 11,4 μg/mL) y borraja (IC50 14,0 μg/mL) presentaron mayor capacidad antioxidante. Mediante las pruebas químicas de caracterización, se detectó la presencia de flavonoides, taninos, triterpenos, alcaloides y saponinas en la mayoría de las especies analizadas (aproximadamente 56-69%); tan sólo un 20% de las mismas mostró la presencia de polifenoles, glucósidos cianogénicos, lactonas, cumarinas, esteroles y antraquinonas. Según los resultados, se podría considerar a estas plantas como fuentes prometedoras de metabolitos secundarios con actividad antioxidante. ABSTRACTThis study evaluated the antioxidant capacity of sixteen medicinal plants: Escoba amarga (Parthenium hysterophons), ajenjo (Artemisia absinthium), guarumo (Cecropia obtusifolia), chaya (Cnidoscolus chayamansa), borraja (Borago officinalis), balsa (Ochroma sp.), linaza (Linum usitatissimum), hierba Luisa (Cymbopogon citratus), toronjil (Melissa officinalis), buganvilla (Bougainvillea spectabilis), alcachofa (Cynara scolymus), guaviduca (Piper carpunya), altamisa (Ambrosia cumanensis), diente de León (Taxacum officinales), buscapina (Parietaria officinalis)and moringa (Moringa oleifera). For this, the DPPH (radical 1, 1-difenil-2-picrilhidrazil) method was used; furthermore, recognition assays of secondary metabolites were performed, in order to obtain the first signs of phytochemical compounds of interest. The free radical scavenging activity of the extracts was expressed as IC50 value (g/mL) (necessary amount to inhibit the formation of 50% of DPPH radical). The low value of IC50 reflects better free radical scavenging action. Although most of the samples tested showed good antioxidant capacity with this method (DPPH), tests of hydroalcoholic extracts show that alcachofa (IC50 9.89 mg/mL), moringa (IC50 11.4 mg/mL) and borraja (IC50 14.0 mg/mL) were those with higher antioxidant capacity. Through chemical characterization tests, the presence of flavonoids, tannins, triterpenes, alkaloids and saponins were detected in most of the analyzed species (approximately 56-69%); only 20% of them showed the presence of polyphenols, cyanogenic glycosides, lactones, coumarins, anthraquinones and sterols. According to the results obtained, these plants might be considered as promising sources of secondary metabolites with antioxidant activity.
Dissertations / Theses on the topic "Y-lactones"
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Garzino, Frédéric. "Synthèse radicalaire asymétrique de y-lactones et de2,3-dihydrofuranes induite par Mn(OAc)3 : Accès des lignanes enantiométriquement purs." Aix-Marseille 2, 2001. http://www.theses.fr/2001AIX22064.
Full textBook chapters on the topic "Y-lactones"
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"HIGH-LEVEL EXPRESSION OF RAT L-GULONO-y-LACTONE OXIDASE IN SILKWORM CELLS WITH A BACULOVIRUS VECTOR." In Flavins and Flavoproteins 1993, 791–94. De Gruyter, 1994. http://dx.doi.org/10.1515/9783110885774-137.
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Taber, Douglass F. "Intramolecular Diels-Alder Cycloaddition: 7-Isocyanoamphilecta- 11(20),15-diene (Miyaoka), (–)-Scabronine G (Kanoh), Basiliolide B (Stoltz), Hirsutellone B (Uchiro), Echinopine A (Chen)." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0078.
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The amphilectane diterpenes, exemplified by 7-isocyanoamphilecta-11(20),15-diene 3, have been little investigated. In the course of a synthesis of 3, Hiroaki Miyaoka of the Tokyo University of Pharmacy and Life Sciences took advantage (Synlett 2011, 547) of the kinetic enolization and silylation of 1 to convert it into a trienone that spontaneously cyclized to 2. Scabronine G 6, isolated from the mushroom Sarcodon scabrosus, was found to enhance the secretion of neurotrophic factors from 1321N1 astrocytoma cells. To set the absolute configuration of the two quaternary centers that are 1, 4 on the cyclohexane ring of 6, Naoki Kanoh and Yoshiharu Iwabuchi of Tohoku University cyclized (Org. Lett. 2011, 13, 2864) 4 to 5. Although described by the authors as a double Michael addition, this transformation has the same connectivity as an intramolecular Diels-Alder cycloaddition. The diterpenes isolated from the genus Thapsia, represented by basiliolide B 9, induce rapid mobilization of intracellular Ca2+ stores. Brian M. Stoltz of Caltech effected (Angew. Chem. Int. Ed. 2011, 50, 3688) Claisen rearrangement of 7 to give an intermediate that cyclized to 8 as a mixture of diastereomers. A significant challenge in the synthesis was the assembly of the delicate enol ether/lactone of 9. Hirsutellone B 12, isolated from Hirsutella nivea, shows significant antituberculosis activity. Hiromi Uchiro of the Tokyo University of Science found it useful (Org. Lett. 2011, 13, 6268) to protect the intermediate unsaturated keto ester by intermolecular cycloaddition with pentamethylcyclopentadiene before constructing the triene of 10. Simple thermolysis reversed the intermolecular addition, opening the way to intramolecular cycloaddition to give 11. The tetracyclic ring system of the diterpene echinopine A 15 represents a substantial synthetic challenge. David Y.-K. Chen of Seoul National University approached this problem (Org. Lett. 2011, 13, 5724) by Pd-mediated cyclization of 13 to the diene, which then underwent intramolecular Diels-Alder cycloaddition to give 14, with control of the relative configuration of two of the three ternary centers of 15. Double bond migration followed by oxidative cleavage of the resulting cyclohexenone then set the stage for the intramolecular cyclopropanation that completed the synthesis of 15.