keyword
MENU ▼
Read by QxMD icon Read
search

lactone

keyword
https://www.readbyqxmd.com/read/28225085/aidp-a-novel-n-acyl-homoserine-lactonase-gene-from-antarctic-planococcus-sp
#1
Wah Seng See-Too, Robson Ee, Yan-Lue Lim, Peter Convey, David A Pearce, Wai-Fong Yin, Kok-Gan Chan
Planococcus is a Gram-positive halotolerant bacterial genus in the phylum Firmicutes, commonly found in various habitats in Antarctica. Quorum quenching (QQ) is the disruption of bacterial cell-to-cell communication (known as quorum sensing), which has previously been described in mesophilic bacteria. This study demonstrated the QQ activity of a psychrotolerant strain, Planococcus versutus strain L10.15(T), isolated from a soil sample obtained near an elephant seal wallow in Antarctica. Whole genome analysis of this bacterial strain revealed the presence of an N-acyl homoserine lactonase, an enzyme that hydrolyzes the ester bond of the homoserine lactone of N-acyl homoserine lactone (AHLs)...
February 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28223313/active-multi-enzyme-assemblies-for-long-chain-olefinic-hydrocarbon-biosynthesis
#2
James K Christenson, Matthew R Jensen, Brandon R Goblirsch, Fatuma Mohamed, Wei Zhang, Carrie M Wilmot, Lawrence P Wackett
Bacteria from different Phyla produce long-chain olefinic hydrocarbons derived from an OleA-catalyzed Claisen condensation of two fatty acyl-CoA substrates, followed by reduction and oxygen elimination reactions catalyzed by the proteins OleB, OleC, and OleD. In this report, OleA, OleB, OleC, and OleD were individually purified as soluble proteins, and all were found to be essential for reconstituting hydrocarbon biosynthesis. Recombinant co-expression of tagged OleABCD proteins from Xanthomonas campestris in Escherichia coli and purification over His6x- and FLAG-columns resulted in OleA separating whilst OleBCD purified together, irrespective of which of the four Ole proteins were tagged...
February 21, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28218529/antibacterial-paramagnetic-quinones-from-actinoallomurus
#3
Marianna Iorio, João Cruz, Matteo Simone, Alice Bernasconi, Cristina Brunati, Margherita Sosio, Stefano Donadio, Sonia I Maffioli
Four metabolites, designated paramagnetoquinone A, B, C, and D (1-4), were isolated from three strains belonging to the actinomycete genus Actinoallomurus. Compounds 1 and 2 showed potent antibacterial activity with MIC values lower than 0.015 μg/mL against Gram-positive pathogens, including antibiotic-resistant strains. Since compounds 1 and 2 were NMR-silent due to the presence of an oxygen radical, structure elucidation was achieved through a combination of derivatizations, oxidations, and analysis of (13)C-labeled compounds...
February 20, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28215600/synthesis-of-dual-action-parthenolide-prodrugs-as-potent-anticancer-agents
#4
Akram Taleghani, Mohammad Ali Nasseri, Mehrdad Iranshahi
Cancer stem cells are responsible for the failure of a large number of cancer treatments and the re-emergence of cancer in patients. Parthenolide is a potent anticancer sesquiterpene lactone that is also able to kill cancer stem cells. The main problem with this compound is its poor solubility in water. To solve this problem, medicinal chemists have tried to prepare amino-derivatives of parthenolide, however, most amino-derivatives have less potency than that of parthenolide. In this paper, we proposed a new approach to synthesize parthenolide derivatives with better solubility and higher potency...
February 1, 2017: Bioorganic Chemistry
https://www.readbyqxmd.com/read/28215152/biological-activities-of-sesquiterpene-lactones-isolated-from-the-genus-centaurea-l-asteraceae
#5
Marina Sokovic, Ana Ciric, Jasmina Glamoclija, Helen Skaltsa
BACKGROUND: In recent years, a growing interest has developed in the field of biological activity of plant metabolites. Research in this area considering antimicrobial, antioxidant, cytotoxic, anti-inflammatory, and other properties, is currently expanding, reporting various species to possess such biological effects. Among them, Centaurea species are well known to be used in ethnomedicine. The Centaurea genus (Asteraceae) is represented by more than 500 species, mostly located in the Mediterranean region and Western Asia...
February 15, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28214230/synthesis-and-cytotoxic-activities-of-goniothalamins-and-derivatives
#6
Anja Weber, Katja Döhl, Julia Sachs, Anja C M Nordschild, Dennis Schröder, Andrea Kulik, Thomas Fischer, Lutz Schmitt, Nicole Teusch, Jörg Pietruszka
Substituted goniothalamins containing cyclopropane-groups were efficiently prepared in high yields and good selectivity. Antiproliferative activity was measured on three human cancer cell lines (A549, MCF-7, HBL-100), to show which of the structural elements of goniothalamins is mandatory for cytotoxicity. We found that the configuration of the stereogenic centre of the δ-lactone plays an important role for cytotoxicity. In our studies only (R)-configured goniothalamins showed antiproliferative activity, whereby (R)-configuration accords to natural goniothalamin (R)-1...
February 6, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28213548/effects-of-gelling-agent-and-extracellular-signaling-molecules-on-the-culturability-of-marine-bacteria
#7
Anita Mac Rygaard, Mariane Schmidt Thøgersen, Kristian Fog Nielsen, Lone Gram, Mikkel Bentzon-Tilia
Only 1 % of marine bacteria are currently culturable using standard laboratory procedures and this is a major obstacle for our understanding of the biology of marine microorganisms and for the discovery of novel microbial natural products. Therefore, the purpose of the present study was to investigate if improved cultivation conditions, including the use of an alternative gelling agent, and supplementation with signaling molecules, could improve the culturability of bacteria from seawater. Substituting agar with gellan gum improved viable counts 3 - 40-fold, depending on medium composition and incubation conditions, with a maximum of 6...
February 17, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28213239/new-urea-modified-paper-substrate-for-enhanced-analytical-performance-of-negative-ion-mode-paper-spray-mass-spectrometry
#8
Jingjing Liu, Yan He, Shuo Chen, Ming Ma, Shouzuo Yao, Bo Chen
Electrospray ionization mass spectrometry (ESI-MS) analysis in the negative ion mode is adversely affected by ionization suppression caused by electrical discharge and the presence of salts. Paper spray mass spectrometry (PS-MS) also suffers from the above phenomenon, being built on principles similar to those of ESI. Herein, we report the use of a paper substrate modified by 1-[3-(trimethoxysilyl)propyl]urea to improve the sensitivity of quantitative PS-MS analysis in the negative ion mode. The obtained results demonstrated that the urea modified paper substrate can effectively bind anions and highly polar compounds in the sample solution, decreasing competitive ionization in the negative ion mode of PS-MS and significantly reducing the signal intensity of Cl(-) adducts...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28211203/first-stereoselective-total-synthesis-of-a-dimeric-naphthoquinonopyrano-%C3%AE-lactone-%C3%AE-actinorhodin
#9
Markus Neumeyer, Reinhard Brückner
We have accomplished the first total synthesis of an isomerically pure naphthoquinonopyrano-γ-lactone dimer, γ-actinorhodin, in eleven steps. Two steps exploit pairs of peri-MeO groups as unusual selectivity controls. The respective MeO groups convey the steric bulk of a bromo or iodo substituent located ortho to one MeO group as steric hindrance into the vicinity of the second MeO group. This relay effect was indispensable for exerting regiocontrol in an aromatic bromination and diastereocontrol in an oxa-Pictet-Spengler cyclization...
February 17, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28209917/artesunate-suppresses-the-viability-and-mobility-of-prostate-cancer-cells-through-uca1-the-sponge-of-mir-184
#10
Yan Zhou, Xiuju Wang, Jianjun Zhang, Aina He, Ya Ling Wang, Kun Han, Yang Su, Junyi Yin, Xiaobin Lv, Haiyan Hu
Artesunate (ART) is a sesquiterpene lactone isolated from the leafy portions of the Chinese herb Artemisia annua. Here, we evaluated the effect of ART on the prostate cancer (PCa) cell lines DU145 and LNCaP and explored its potential mechanisms. ART inhibited the viability and mobility of DU145 and LNCaP cells. Mechanistically, we found that UCA1, one of the most important lncRNAs in malignancies of the urinary system, may be a potential mediator contributing to the tumor suppressor function of ART. First, the UCA1 level was reduced significantly after being exposed to ART...
February 16, 2017: Oncotarget
https://www.readbyqxmd.com/read/28203368/a-nationwide-survey-of-anthelmintic-treatment-failure-on-sheep-farms-in-ireland
#11
Jason D Keegan, Orla M Keane, Barbara Good, Theo De Waal, Marian Denny, James P Hanrahan, William Fitzgerald, Maresa Sheehan
BACKGROUND: Between 2013 and 2015 the Department of Agriculture, Food and the Marine (DAFM) administered a sheep technology adoption programme (STAP), with the aim of increasing profitability on Irish sheep farms by encouraging the adoption of best management practices. One of the options available to STAP participants was to test the efficacy of the anthelmintic treatment (benzimadazole, levamisole or macrocyclic lactone) used in their flocks by means of a drench test, which is a modification of the faecal egg count reduction test; individual faecal samples were collected from the same group of lambs before and after anthelmintic treatment, the number of eggs present pre and post treatment was subsequently determined from a pooled sample...
2017: Irish Veterinary Journal
https://www.readbyqxmd.com/read/28198613/the-discovery-of-a-%C3%AE-lactone-synthetase
#12
Frank M Raushel
No abstract text is available yet for this article.
February 15, 2017: Biochemistry
https://www.readbyqxmd.com/read/28197135/cloning-and-characterization-of-the-autoinducer-synthase-gene-from-lipid-degrading-bacterium-cedecea-neteri
#13
Kian-Hin Tan, Kah-Yan How, Jia-Yi Tan, Wai-Fong Yin, Kok-Gan Chan
The process of intercellular communication among bacteria, termed quorum sensing (QS), is mediated by small diffusible molecules known as the autoinducers. QS allows the population to react to the change of cell density in unison, in processes such as biofilm formation, plasmid conjugation, virulence, motility and root nodulation. In Gram-negative proteobacteria, N-acyl homoserine lactone (AHL) is the common "language" to coordinate gene expression. This signaling molecule is usually synthesized by LuxI-type proteins...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28194806/allergenic-sesquiterpene-lactones-from-cushion-bush-leucophyta-brownii-cass-new-and-old-sensitizers-in-a-shrub-turned-a-pot-plant
#14
Evy Paulsen, Mette G Hyldgaard, Klaus E Andersen, Flemming Andersen, Lars P Christensen
BACKGROUND: The Australian cushion bush (Leucophyta brownii) of the Compositae family of plants has become a popular pot and container plant. The plant produces the sesquiterpene lactone allergen calocephalin. OBJECTIVES: To assess the sensitizing potential of sesquiterpene lactones from cushion bush. PATIENTS/MATERIALS/METHODS: Eleven Compositae-sensitive patients were patch tested with seven sesquiterpene lactones isolated from cushion bush...
February 14, 2017: Contact Dermatitis
https://www.readbyqxmd.com/read/28190935/reassignment-of-the-absolute-configuration-of-plakinidone-from-the-sponge-consortium-plakortis-halichondrioides-xestospongia-deweerdtae-using-a-combination-of-synthesis-and-a-chiroptical-approach
#15
Carlos Jiménez-Romero, Joanna E Rode, Abimael D Rodríguez
Recent work by Wu et al. in connection with the first synthesis of the marine natural product plakinidone revealed that the most salient feature of its purported structure, a six-membered perlactone moiety, was in fact a five-membered lactone, i.e. a 3-methyl-4-hydroxy-2(5H)-furanone or tetronic acid ring. With the planar structure of plakinidone confidently revised, we undertook a new investigation to unambiguously establish its absolute configuration. Upon preparing two stable derivatives 1 and 5 from a sample of naturally occurring plakinidone extracted from the sponge association Plakortis halichondriodes-Xetospongia deweerdtae, the absolute configuration was assigned by synthesis and vibrational and electronic circular dichroism (VCD and ECD) measurements in combination with density functional theory calculations at the B3LYP/aug-cc-pVDZ/PCM(CH3CN) level of theory...
June 2016: Tetrahedron, Asymmetry
https://www.readbyqxmd.com/read/28186774/quantitative-map-of-%C3%AE-lactone-induced-virulence-regulation
#16
Joanna Krysiak, Matthias Stahl, Jan Vomacka, Christian Fetzer, Markus Lakemeyer, Anja Fux, Stephan A Sieber
β-Lactones have recently been introduced as the first selective ClpP inhibitors that attenuate virulence of both sensitive Staphylococcus aureus and multiresistant strains (MRSA). Although previous knockout studies showed that ClpP is essential for S. aureus alpha-toxin production, a link between β-lactone inhibition and molecular virulence mechanisms has been lacking so far. We here perform a chemical-proteomic approach to elucidate antivirulence pathways. First, we demonstrate by gel-free activity-based protein profiling that ClpP is the predominant target of β-lactones...
February 10, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28186758/strategic-approach-to-8-azacoumarins
#17
Dong Wang, Yuxi Wang, Junjie Zhao, Meng Shen, Jianyong Hu, Zhenlin Liu, Linna Li, Furen Xue, Peng Yu
8-Azacoumarins have emerged as a promising class of compounds but are rarely explored due to challenging access. A novel, general, and practical method is provided for this class of compounds. The key lactonization step employs trans-acrylic acid attached pyridine N-oxides as the starting material, with acetic anhydride as both the activation agent and the solvent. Multiple transformations were involved in this reaction, including conjugate addition, nucleophilic aromatic substitution, and elimination. These studies provide the basis for access to 8-azacoumarins, enabling future work including the discovery and development of novel coumarin-type drugs, fluorescent probes, photolabile protecting groups, and other active molecules...
February 10, 2017: Organic Letters
https://www.readbyqxmd.com/read/28186335/characterization-of-a-continuous-agitated-cell-reactor-for-oxygen-dependent-biocatalysis
#18
Asbjørn Toftgaard Pedersen, Teresa Melo de Carvalho, Euan Sutherland, Gustav Rehn, Robert Ashe, John M Woodley
Biocatalytic oxidation reactions employing molecular oxygen as the electron acceptor are difficult to conduct in a continuous flow reactor because of the requirement for high oxygen transfer rates. In this paper, the oxidation of glucose to glucono-1,5-lactone by glucose oxidase was used as a model reaction to study a novel continuous agitated cell reactor (ACR). The ACR consists of ten cells interconnected by small channels. An agitator is placed in each cell, which mixes the content of the cell when the reactor body is shaken by lateral movement...
February 10, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28181527/bigelovin-triggered-apoptosis-in-colorectal-cancer-in-vitro-and-in-vivo-via-upregulating-death-receptor-5-and-reactive-oxidative-species
#19
Mingyue Li, Li-Hua Song, Grace Gar-Lee Yue, Julia Kin-Ming Lee, Li-Mei Zhao, Lin Li, Xunian Zhou, Stephen Kwok-Wing Tsui, Simon Siu-Man Ng, Kwok-Pui Fung, Ning-Hua Tan, Clara Bik-San Lau
Colorectal cancer (CRC) is the third most prevalent cancer and the third highest cancer-related mortality in the United States. Bigelovin, a sesquiterpene lactone isolated from Inula helianthus aquatica, has been proven to induce apoptosis and exhibit anti-inflammatory and anti-angiogenic activities. However, the effects of bigelovin on CRC and underlying mechanisms have not been explored. The present study demonstrated that bigelovin exhibited potent anti-tumor activities against CRC in vitro and in vivo. Bigelovin suppressed cell proliferation and colony formation and induced apoptosis in human colorectal cancer HT-29 and HCT 116 cells in vitro...
February 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28179138/the-interdigitating-loop-of-the-enolase-superfamily-as-a-specificity-binding-determinant-or-flying-buttress
#20
REVIEW
Stephen L Bearne
BACKGROUND: Enzymes of the enolase superfamily (ENS) are mechanistically diverse, yet share a common partial reaction (abstraction of the α-proton from a carboxylate substrate). While the catalytic machinery responsible for the deprotonation reaction has been conserved, divergent evolution has led to numerous ENS members that catalyze different overall reactions. This rich functional diversity has made the ENS an excellent model system for developing the approaches necessary to validate enzyme function...
February 4, 2017: Biochimica et Biophysica Acta
keyword
keyword
58757
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"