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https://www.readbyqxmd.com/read/29681907/exogenous-applications-of-brassinosteroids-improve-color-of-red-table-grape-vitis-vinifera-l-cv-redglobe-berries
#1
Alexis E Vergara, Katy Díaz, Rodrigo Carvajal, Luis Espinoza, José A Alcalde, Alonso G Pérez-Donoso
Color and other quality parameters of "Redglobe" grape ( Vitis vinifera L.) berries were evaluated after treatment with brassinosteroid (BR) analogs. Three BRs analogs (24-epibrassinolide, Triol, or Lactone) were applied at three concentrations (0.0, 0.4, or 0.8 mg⋅L-1 ), at the onset of veraison. A commercial formulation (B-2000® ) was also applied, at a recommended rate of 0.06 mg⋅L-1 . The tested BR analogs were effective improving berry color (evaluated as color index for red grapes, CIRG), increasing the levels of soluble solids and anthocyanins, and changing the types of anthocyanins present without altering other quality and yield parameters...
2018: Frontiers in Plant Science
https://www.readbyqxmd.com/read/29681758/ozonolysis-of-%C3%AE-%C3%AE-farnesene-mixture-analysis-of-gas-phase-and-particulate-reaction-products
#2
Mohammed Jaoui, Michael Lewandowski, John H Offenberg, Kenneth S Docherty, Tadeusz E Kleindienst
Atmospheric oxidation of sesquiterpenes has been of considerable interest recently because of their likely contribution to ambient organic aerosol, but farnesene oxidation has been reported in only a few studies and with limited data. In the present study, a detailed chemical analysis of the organic fraction of gas and particle phases originating from the ozonolysis of a mixture of α-farnesene and β-farnesene was carried out in a 14.5 m3 smog chamber. More than 80 organic compounds bearing OH functionality were detected for the first time in this system in the gas and particle phases...
November 2017: Atmospheric Environment
https://www.readbyqxmd.com/read/29677683/application-of-solid-phase-microextraction-followed-by-liquid-chromatography-mass-spectrometry-in-the-determination-of-antibiotic-drugs-and-their-metabolites-in-human-whole-blood-and-tissue-samples
#3
Malgorzata Szultka-Mlynska, Pawel Pomastowski, Boguslaw Buszewski
A sensitive, rapid and specific analytical method using high performance liquid chromatography coupled with mass spectrometry (HPLC-QqQ-MS) was developed to determine selected antibiotic drugs and their metabolites (amoxicillin, cefotaxime, ciprofloxacin, clindamycin and metronidazole; amoxycilloic acid, 4-hydroxyphenyl glycyl amoxicillin, desacetyl cefotaxime, 3-desacetyl cefotaxime lactone, ciprofloxacin N-oxide, N-demethylclindamycin, clindamycin sulfoxide, and hydroxy metronidazole) in human whole blood and vascularized tissue after single oral administration...
April 12, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29674720/stereoselective-photoredox-ring-opening-polymerization-of-o-carboxyanhydrides
#4
Quanyou Feng, Lei Yang, Yongliang Zhong, Dong Guo, Guoliang Liu, Linghai Xie, Wei Huang, Rong Tong
Biodegradable polyesters with various tacticities have been synthesized by means of stereoselective ring-opening polymerization of racemic lactide and β-lactones but with limited side-chain groups. However, stereoselective synthesis of functional polyesters remains challenging from O-carboxyanhydrides that have abundant pendant side-chain functional groups. Herein we report a powerful strategy to synthesize stereoblock polyesters by stereoselective ring-opening polymerization of racemic O-carboxyanhydrides with the use of photoredox Ni/Ir catalysts and a selected Zn complex with an achiral ligand...
April 19, 2018: Nature Communications
https://www.readbyqxmd.com/read/29666543/spoilage-of-refrigerated-litopenaeus-vannamei-eavesdropping-on-acinetobacter-acyl-homoserine-lactones-promotes-the-spoilage-potential-of-shewanella-baltica
#5
Suqin Zhu, Haohao Wu, Caili Zhang, Jinxin Jie, Zunying Liu, Mingyong Zeng, Changyun Wang
Shewanella baltica and Acinetobacter are among the predominant spoilage bacteria in refrigerated shrimp ( Litopenaeus vannamei ). S. baltica are incapable of producing acyl-homoserine lactone (AHL) quorum sensing signals, but can respond to environmental AHLs. In this paper, Acinetobacter was found to produce three AHLs, i.e. N -butanoyl-l-homoserine lactone (C4-HSL), N -(3-oxohexanoyl)-l-homoserine lactone (O-C6-HSL) and N -(3-oxooctanoyl)-l-homoserine lactone (O-C8-HSL), according to thin-layer chromatography using the bioreporter Agrobacterium tumefaciens A136...
May 2018: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/29665476/bioactive-norditerpenoids-from-cephalotaxus-fortunei-var-alpina-and-c-lanceolata
#6
Ling Ni, Xiu-Hong Zhong, Xiao-Jiao Chen, Bing-Jie Zhang, Mei-Fen Bao, Xiang-Hai Cai
Twenty-eight naturally occurring Cephalotaxus tropone analogues, including 19 previously undescribed ones, were identified from Cephalotaxus fortunei Hook. var. alpina H. L. Li and C. lanceolata K. M. Feng. The presence of the C20 cephinoids A-E revealed that these tropones were assigned to the norditerpenoids and were perhaps derived from labdane-type diterpenoids. These norditerpenoids showed excellent cytotoxicity against human cancer cells (IC50 , 20-0.1 μM) in vitro. The SAR (structure-activity relationship) analysis disclosed that the tropone moiety and the lactone ring were crucial structural features for the observed activities...
April 14, 2018: Phytochemistry
https://www.readbyqxmd.com/read/29664914/ahl-lactonase-expression-in-three-marine-emerging-pathogenic-vibrio-spp-reduces-virulence-and-mortality-in-brine-shrimp-artemia-salina-and-manila-clam-venerupis-philippinarum
#7
Marta Torres, José Carlos Reina, Juan Carlos Fuentes-Monteverde, Gerardo Fernández, Jaime Rodríguez, Carlos Jiménez, Inmaculada Llamas
Bacterial infectious diseases produced by Vibrio are the main cause of economic losses in aquaculture. During recent years it has been shown that the expression of virulence genes in some Vibrio species is controlled by a population-density dependent gene-expression mechanism known as quorum sensing (QS), which is mediated by the diffusion of signal molecules such as N-acylhomoserine lactones (AHLs). QS disruption, especially the enzymatic degradation of signalling molecules, known as quorum quenching (QQ), is one of the novel therapeutic strategies for the treatment of bacterial infections...
2018: PloS One
https://www.readbyqxmd.com/read/29664292/alkaloids-from-pleiocarpa-pycnantha-pleiocarinine-a-bisindoline-alkaloid-formed-by-connecting-two-aspidofractinine-moieties-via-a-methylene-unit
#8
Joseph T Ndongo, Joséphine N Mbing, Aymeric Monteillier, Michel F Tala, Michael Rütten, Daniel Mombers, Muriel Cuendet, Dieudonné E Pegnyemb, Birger Dittrich, Hartmut Laatsch
Three new alkaloids, janetinine (1a), pleiocarinine (2), and huncaniterine B (3a), and 13 known compounds, pleiomutinine (3b), huncaniterine A (3c), 1-carbomethoxy-β-carboline (4), evoxanthine (5), deformyltalbotine acid lactone (6), pleiocarpamine (7), N4 -methyl-10-hydroxygeissoschizol (8), spegatrine (9), neosarpagine (10), aspidofractinine (11), N1 -methylkopsinin (12), pleiocarpine (13), and N1 -methylkopsinin- N4 -oxide (14), were isolated from the stem bark of Pleiocarpa pycnantha. Janetinine (1a) is a carbazole alkaloid; in pleiocarinine (2), two aspidofractinine-type alkaloids are bridged by a methylene unit in an unprecedented way, and huncaniterine B (3a) is a pleiocarpamine-aspidofractinine-type dimer...
April 17, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29662232/characterization-of-aiik-an-ahl-lactonase-from-kurthia-huakui-lam0618-t-and-its-application-in-quorum-quenching-on-pseudomonas-aeruginosa-pao1
#9
Weiwei Dong, Jie Zhu, Xiang Guo, Delong Kong, Qi Zhang, Yiqing Zhou, Xiaoyang Liu, Shumiao Zhao, Zhiyong Ruan
N-Acyl homoserine lactones (AHLs) act as the key quorum sensing (QS) signal molecules in gram-negative bacteria, which coordinates gene expression and then activates various processes, including biofilm formation and production of virulence factors in some pathogens. Quorum quenching (QQ), which is the inactivation of the signal molecules by means of enzymatic degradation or modification, inhibits the processes of QS rather than killing the pathogens and is a promising antipathogenic strategy to control the bacterial pathogens...
April 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29659511/quorum-sensing-and-quorum-quenching-in-agrobacterium-a-go-no-go-system
#10
REVIEW
Yves Dessaux, Denis Faure
The pathogen Agrobacterium induces gall formation on a wide range of dicotyledonous plants. In this bacteria, most pathogenicity determinants are borne on the tumour inducing (Ti) plasmid. The conjugative transfer of this plasmid between agrobacteria is regulated by quorum sensing (QS). However, processes involved in the disturbance of QS also occur in this bacteria under the molecular form of a protein, TraM, inhibiting the sensing of the QS signals, and two lactonases BlcC (AttM) and AiiB that degrade the acylhomoserine lactone (AHL) QS signal...
April 16, 2018: Genes
https://www.readbyqxmd.com/read/29658717/asymmetric-synthesis-of-gonytolide-a-strategic-use-of-an-aryl-halide-blocking-group-for-oxidative-coupling
#11
Xiaowei Wu, Takayuki Iwata, Adam Scharf, Tian Qin, Kyle D Reichl, John A Porco
The first synthesis of the chromanone lactone dimer gonytolide A has been achieved employing vanadium(V)-mediated oxidative coupling of the monomer gonytolide C. An ortho-bromine blocking group strategy was employed to favor para-para coupling and to enable kinetic resolution of (±)-gonytolide C. Asymmetric conjugate reduction enabled practical kinetic resolution of a chiral, racemic precursor and the asymmetric synthesis of (+)-gonytolide A and its atropisomer.
April 16, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29658716/effects-of-substituents-on-the-aromatic-ring-of-lignano-9-9-lactone-on-plant-growth-inhibitory-activity
#12
Satoshi Yamauchi, Yasuka Yamashita, Asuka Nishimoto, Hisashi Nishiwaki
The relationship between the structure of lignano-9,9'-lactone (2,3-dibenzylbutyrolactone) and its activity as a plant growth regulator was clarified. Derivatives with higher plant growth inhibitory activity than natural dimethylmatairesinol 4 were synthesized. The 2-hydroxy-7-Z-ene derivative 42 displayed growth inhibitory activity against both the shoots (IC50 = 0.65 mM) and roots (IC50 = 0.43 mM) of lettuce seedlings. Regiospecific activity was observed. The 2,3-dihydroxy derivative 24 showed the highest growth inhibitory activity against both the shoots (IC50 = 0...
April 16, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29657234/-%C3%A2-terreinlactone-a-a-pair-of-3-substituted-%C3%AE-lactone-enantiomers-derived-from-terrein-from-the-fungus-aspergillus-terreus
#13
Xuwen Zhang, Zhaodi Wu, Yongji Lai, Dongyan Li, Jianping Wang, Zengwei Luo, Yongbo Xue, Hucheng Zhu, Chunmei Chen, Yonghui Zhang
Terreinlactone A (1a/1b), a pair of 3-substituted δ-lactone enantiomers, and terreinlactone B (2), a new biosynthetic intermediate of 1a/1b, were isolated from Aspergillus terreus, along with their biosynthetic precursor (+)-terrein (3) and (+)-isoterrein (4). Compounds 1a and 1b were separated by using a Daicel chiral-pak ASH column eluting with n-hexane-EtOH (80:20). The structures of 1a/1b with absolute configurations were determined by comprehensive spectroscopic analyses and electronic circular dichroic (ECD) calculations...
April 13, 2018: Chemical & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/29657018/wolbachia-doxycycline-and-macrocyclic-lactones-new-prospects-in-the-treatment-of-canine-heartworm-disease
#14
L Kramer, S Crosara, G Gnudi, M Genchi, C Mangia, A Viglietti, C Quintavalla
Melarsomine dihydrochloride (Immiticide®, Merial) is the only approved adulticidal drug for the treatment of canine heartworm disease (HWD). However, in cases where arsenical therapy is not possible or is contraindicated, a monthly heartworm preventive along with doxycycline for a 4-week period, which targets the bacterial endosymbiont Wolbachia, might be considered. There are published reports on the efficacy of ivermectin and doxycycline in both experimentally and naturally infected dogs, but no data on the use of other macrocyclic lactones (MLs) with a similar treatment regime...
April 30, 2018: Veterinary Parasitology
https://www.readbyqxmd.com/read/29656990/synthesis-and-antiproliferative-activity-of-derivatives-of-the-phyllanthusmin-class-of-arylnaphthalene-lignan-lactones
#15
John L Woodard, Andrew C Huntsman, Pratiq A Patel, Hee-Byung Chai, Ragu Kanagasabai, Soumendrakrishna Karmahapatra, Alexandria N Young, Yulin Ren, Malcolm S Cole, Denisse Herrera, Jack C Yalowich, A Douglas Kinghorn, Joanna E Burdette, James R Fuchs
A series of arylnaphthalene lignan lactones based on the structure of the phyllanthusmins, a class of potent natural products possessing diphyllin as the aglycone, has been synthesized and screened for activity against multiple cancer cell lines. SAR exploration was performed on both the carbohydrate and lactone moieties of this structural class. These studies have revealed the importance of functionalization of the carbohydrate hydroxy groups with both acetylated and methylated analogues showing increased potency relative to those with unsubstituted sugar moieties...
March 23, 2018: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/29651246/lactone-component-from-ligusticum-chuanxiong-alleviates-myocardial-ischemia-injury-through-inhibiting-autophagy
#16
Gang Wang, Guoliang Dai, Jie Song, Maomao Zhu, Ying Liu, Xuefeng Hou, Zhongcheng Ke, Yuanli Zhou, Huihui Qiu, Fujing Wang, Nan Jiang, Xiaobin Jia, Liang Feng
The dysregulation of autophagy is associated with a series of cardiovascular diseases, such as myocardial ischemia injury. Lactone component from Ligusticum chuanxiong (LLC) is the major constituent of the traditional Chinese herb L. chuanxiong Hort., which has been reported to hold potential cardioprotective effects. In this study, to determine whether LLC protects the heart through regulation of autophagy, we explored the effects of LLC on cardioprotection and autophagy in myocardial ischemia injured rats and H9c2 cardiomyocytes...
2018: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29649493/inonotolides-a-c-isopimarane-diterpenoid-lactones-from-inonotus-sinensis
#17
Jian-Hai Ding, Zheng-Hui Li, Tao Feng, Ji-Kai Liu
Three new isopimarane diterpenoid lactones, named inonotolides A-C (1-3), were isolated from cultures of the basidiomycete Inonotus sinensis. Their structures were elucidated on the basis of extensive spectroscopic studies and the structure of inonotolide A (1) was confirmed by single-crystal X-ray crystallographic analysis. All compounds were evaluated for their cytotoxicities against five human cancer cell lines.
April 9, 2018: Fitoterapia
https://www.readbyqxmd.com/read/29648840/lewis-base-catalyzed-reductive-aldol-reaction-to-access-quaternary-carbons
#18
Yvonne C DePorre, James R Annand, Sukanta Bar, Corinna S Schindler
A synthetic method for the efficient construction of β-hydroxylactones and lactams bearing α-quaternary carbon centers is described. This transformation relies on an electronically differentiated Lewis base catalyst, which is uniquely capable of promoting a reductive aldol reaction of α,α-disubstituted and α,α,β-trisubstituted enones. This approach provides a valuable synthetic alternative for carbon-carbon bond formation in complex molecular settings due to its orthogonal reactivity compared to that of traditional aldol reactions...
April 12, 2018: Organic Letters
https://www.readbyqxmd.com/read/29648789/copper-catalyzed-oxidative-carbon-carbon-and-or-carbon-heteroatom-bond-formation-with-o-2-or-internal-oxidants
#19
Xiaodong Tang, Wanqing Wu, Wei Zeng, Huanfeng Jiang
Selective oxidation, a fundamental organic transformation of critical importance, produces value-added products from simple organic molecules. This process is extensively used to incorporate heteroatoms into carbon-based molecules, where high-valent metal salts, hypervalent halogen reagents, and peroxides are widely used as oxidants. Oxidation reactions are extremely challenging because their selectivity is hard to control and/or they form significant quantities of unwanted waste derived from the stoichiometric oxidants...
April 12, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29644802/divergent-total-syntheses-of-enmein-type-natural-products-enmein-isodocarpin-and-sculponin-r
#20
Saiyong Pan, Sicong Chen, Guangbin Dong
Divergent total syntheses of enmein-type natural products, (-)-enmein, (-)-isodocarpin and (-)-sculponin R, have been achieved in a concise fashion. Key features of the strategy include (a) an efficient early-stage cage formation to control succeeding diastereoselectivity, (b) an one-pot acylation/akylation/lactonization to construct the C-ring and C8 quarternary center, (c) a reductive alkenylation approach to construct enmain D/E rings and (d) a flexible route to allow divergent syntheses of three natural products...
April 12, 2018: Angewandte Chemie
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