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https://www.readbyqxmd.com/read/29471265/role-of-rpos-in-stress-resistance-quorum-sensing-and-spoilage-potential-of-pseudomonas-fluorescens
#1
Xiaoxiang Liu, Lei Ji, Xu Wang, Jianrong Li, Junli Zhu, Aihua Sun
Microorganism activities are considered the main cause of most food spoilage, leading to great economic losses. Pseudomonas fluorescens is a Gram-negative bacterium that is widely found in food and has high spoilage activity. RpoS is considered an important global regulator involved in stress survival and virulence in many pathogens. Thus, it is very possible that RpoS plays an important role in spoilage regulation in P. fluorescens. In this study an in-frame deletion mutation of rpoS was constructed to explore its function in P...
February 14, 2018: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/29468753/f1012-2-inhibits-the-growth-of-triple-negative-breast-cancer-through-induction-of-cell-cycle-arrest-apoptosis-and-autophagy
#2
Shasha Tian, Yan Chen, Bo Yang, Chenghua Lou, Rui Zhu, Yaping Zhao, Huajun Zhao
Sesquiterpene lactones (SLs) are plant-derived constituents that have been proved to have potential antitumour activity. However, the intracellular molecular targets of SLs and the underlying molecular mechanisms have not been well elucidated. Here, we report that F1012-2, a novel SL active fraction, isolated from Eupatorium lindleyanum DC., can significantly inhibit the growth of triple-negative breast cancer (TNBC) cells (MDA-MB-231 and MDA-MB-468) but has no obvious inhibitory effect on the growth of human mammary epithelial cells (MCF-10A)...
February 22, 2018: Phytotherapy Research: PTR
https://www.readbyqxmd.com/read/29468054/in-vitro-activity-of-ivermectin-against-staphylococcus-aureus-clinical-isolates
#3
Shoaib Ashraf, Umer Chaudhry, Ali Raza, Debasri Ghosh, Xin Zhao
Background: Ivermectin is an endectocide against many parasites. Though being a macrocyclic lactone, its activity against bacteria has been less known, possibly due to the fact that micromolar concentrations at tissue levels are required to achieve a therapeutic effect. Among pathogenic bacteria of major medical significance, Staphylococcus aureus cause a number of diseases in a wide variety of hosts including humans and animals. It has been attributed as one of the most pathogenic organisms...
2018: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/29467483/clove-bud-oil-modulates-pathogenicity-phenotypes-of-the-opportunistic-human-pathogen-pseudomonas-aeruginosa
#4
Jayalekshmi Haripriyan, Athira Omanakuttan, Nitasha D Menon, Muralidharan Vanuopadath, Sudarslal Sadasivan Nair, Ross Corriden, Bipin G Nair, Victor Nizet, Geetha B Kumar
Earlier studies from our laboratory have demonstrated that clove bud oil (CBO) attenuates expression of certain virulence factors of Pseudomonas aeruginosa PAO1. Here, we probe more deeply into the effect of CBO on four pseudomonal proteases - elastase A, elastase B, protease IV and alkaline protease - each known to play key roles in disease pathogenesis. CBO inhibited the activity of these proteases present in the bacterial culture supernatant. Zymography studies indicated that these proteases can activate host matrix metalloproteases (MMPs) to establish infection, through conversion of pro-MMP-2 to active MMP-2...
February 21, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29463534/alginate-oligosaccharide-induced-modification-of-the-lasi-lasr-and-rhli-rhlr-quorum-sensing-systems-in-pseudomonas-aeruginosa
#5
Alison A Jack, Saira Khan, Lydia C Powell, Manon F Pritchard, Konrad Beck, Hina Sadh, Lucy Sutton, Alessandra Cavaliere, Hannah Florance, Philip D Rye, David W Thomas, Katja E Hill
Pseudomonas aeruginosa plays a major role in many chronic infections. Its ability to readily form biofilms contributes to its success as an opportunistic pathogen and its resistance/tolerance to antimicrobial/antibiotic therapy. A low molecular weight alginate oligomer (OligoG CF-5/20), derived from marine algae, has previously been shown to impair motility in P. aeruginosa biofilms and disrupt pseudomonal biofilm assembly. As these bacterial phenotypes are regulated by quorum sensing (QS), we hypothesized that OligoG CF-5/20 may induce alterations in QS signalling in P...
February 20, 2018: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29462892/high-prevalence-of-quorum-sensing-and-quorum-quenching-activity-among-cultivable-bacteria-and-metagenomic-sequences-in-the-mediterranean-sea
#6
Andrea Muras, Mario López-Pérez, Celia Mayer, Ana Parga, Jaime Amaro-Blanco, Ana Otero
There is increasing evidence being accumulated regarding the importance of N -acyl homoserine lactones (AHL)-mediated quorum-sensing (QS) and quorum-quenching (QQ) processes in the marine environment, but in most cases, data has been obtained from specific microhabitats, and subsequently little is known regarding these activities in free-living marine bacteria. The QS and QQ activities among 605 bacterial isolates obtained at 90 and 2000 m depths in the Mediterranean Sea were analyzed. Additionally, putative QS and QQ sequences were searched in metagenomic data obtained at different depths (15-2000 m) at the same sampling site...
February 16, 2018: Genes
https://www.readbyqxmd.com/read/29462873/the-lewis-pair-polymerization-of-lactones-using-metal-halides-and-n-heterocyclic-olefins-theoretical-insights
#7
Jan Meisner, Johannes Karwounopoulos, Patrick Walther, Johannes Kästner, Stefan Naumann
Lewis pair polymerization employing N -Heterocyclic olefins (NHOs) and simple metal halides as co-catalysts has emerged as a useful tool to polymerize diverse lactones. To elucidate some of the mechanistic aspects that remain unclear to date and to better understand the impact of the metal species, computational methods have been applied. Several key aspects have been considered: (1) the formation of NHO-metal halide adducts has been evaluated for eight different NHOs and three different Lewis acids, (2) the coordination of four lactones to MgCl₂ was studied and (3) the deprotonation of an initiator (butanol) was investigated in the presence and absence of metal halide for one specific Lewis pair...
February 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29462785/the-plant-sesquiterpene-lactone-parthenoide-inhibits-wnt-%C3%AE-catenin-signaling-by-blocking-synthesis-of-the-transcriptional-regulators-tcf4-lef1
#8
Xiaoliang Zhu, Chunmao Yuan, Chenyang Tian, Chen Li, Fen Nie, Xiaomin Song, Rong Zeng, Dianqing Wu, Xiaojiang Hao, Lin Li
The Wnt/β-catenin pathway is essential for embryonic development and homeostasis, but excessive activation of this pathway is frequently observed in various human diseases, including cancer. Current therapeutic drugs targeting the Wnt pathway often lack sufficient efficacy, and new compounds targeting this pathway are therefore greatly needed. Here, we report that the plant-derived natural product parthenoide (PTL), a sesquiterpene lactone, inhibits Wnt signaling. We found that PTL dose-dependently inhibits Wnt3a- and CHIR-induced transcriptional activity assessed with the T-cell factor/lymphoid enhancer factor(TCF/LEF)-firefly luciferase (TOPFlash) assay in HEK293 cells...
February 9, 2018: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29462557/honeydew-honeys-a-review-on-characterization-and-authentication-of-the-botanical-and-geographical-origin
#9
Consuelo Pita-Calvo, Manuel Vazquez
The commercial interest in honeydew honeys (from secretions of plants or excretions of plant-sucking insects on plants) is increasing due to the higher therapeutic properties than those of most blossom honeys (from nectar). However, honeydew honeys have been less studied than blossom honeys. In this work, studies carried out to characterize and authenticate honeydew honeys by botanical and geographic origins have been reviewed. The identification of the honey origin has been approached by two ways: chemical markers and development of analytical methodology combined with multivariate analysis...
February 20, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29461058/intramolecular-photocycloaddition-of-2-5h-furanones-to-temporarly-tethered-terminal-alkenes-as-a-stereoselective-source-of-enantiomerically-pure-polyfunctionalyzed-cyclobutanes
#10
Yangchun Xin, Luis Rodríguez-Santiago, Mariona Sodupe, Angel Alvarez-Larena, Felix Busque, Ramon Alibés
Allyloxymethyloxymethyl and 4-pentenoyloxymethyl substituents have been used as tethered groups to study the intramolecular [2+2] photocycloaddition of chiral 5-substituted 2(5H)-furanones. The photoreactions proceed in good yield and provide regio- and diastereoselectively the expected tricyclic compounds with complementary regioselectivity which depends on whether the vinyl chain is attached to the furanone by an acetal or an ester linkage. Computational simulations agree with experimental observations and indicate that the origin of the different observed regioselectivity in the intramolecular photochemical reaction of lactones 5 and 6 arises from the relative stability of the initial conformers...
February 20, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29459105/sequestration-and-utilization-of-carbon-dioxide-by-chemical-and-biological-methods-for-biofuels-and-biomaterials-by-chemoautotrophs-opportunities-and-challenges
#11
REVIEW
Indu Shekhar Thakur, Manish Kumar, Sunita J Varjani, Yonghong Wu, Edgard Gnansounou, Sindhu Ravindran
To meet the CO2 emission reduction targets, carbon dioxide capture and utilization (CCU) comes as an evolve technology. CCU concept is turning into a feedstock and technologies have been developed for transformation of CO2 into useful organic products. At industrial scale, utilization of CO2 as raw material is not much significant as compare to its abundance. Mechanisms in nature have evolved for carbon concentration, fixation and utilization. Assimilation and subsequent conversion of CO2 into complex molecules are performed by the photosynthetic and chemolithotrophic organisms...
February 10, 2018: Bioresource Technology
https://www.readbyqxmd.com/read/29457979/the-samholides-swinholide-related-metabolites-from-a-marine-cyanobacterium-cf-phormidium-sp
#12
Yiwen Tao, Pinglin Li, Daojing Zhang, Evgenia Glukhov, Lena Gerwick, Chen Zhang, Thomas F Murray, William H Gerwick
Cancer cell cytotoxicity was used to guide the isolation of nine new swinholide-related compounds, named samholides A-I (1-9), from an American Samoan marine cyanobacterium cf. Phormidium sp. Their structures were determined by extensive analysis of 1D and 2D NMR spectroscopic data. The new compounds share an unusual 20-demethyl 44-membered lactone ring comprised of two monomers, and they demonstrate structural diversity arising from geometric isomerization of double bonds, sugar units with unique glyceryl moieties and varied methylation patterns...
February 19, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29457733/fe-iii-catalyzed-hydroallylation-of-unactivated-alkenes-with-morita-baylis-hillman-adducts
#13
Jifeng Qi, Jing Zheng, Sunliang Cui
An Fe(III)-catalyzed hydroallylation of unactivated alkenes with Morita-Baylis-Hillman adducts via an Fe-catalyzed process is described. A variety of alkenes, including mono-, di-, and trisubstituted alkenes, could all smoothly convert to structural diversified cinnamates in this protocol. Interestingly, when the hydroxyl-containing alkenes were used, various lactones could be rapidly assembled. Moreover, this protocol could be applied to late-stage functionalization of natural products.
February 19, 2018: Organic Letters
https://www.readbyqxmd.com/read/29457628/a-coupled-in-vitro-in-vivo-approach-for-engineering-a-heterologous-type-iii-pks-to-enhance-polyketide-biosynthesis-in-saccharomyces-cerevisiae
#14
Christopher R Vickery, Javier Cardenas, Marianne Bowman, Michael D Burkart, Nancy A Da Silva, Joseph P Noel
Polyketides are attractive compounds for uses ranging from biorenewable chemical precursors to high-value therapeutics. In many cases, synthesis in a heterologous host is required to produce these compounds in industrially relevant quantities. The type III polyketide synthase 2-pyrone synthase (2-PS) from Gerbera hybrida was used for the production of triacetic acid lactone (TAL) in Saccharomyces cerevisiae. Initial in vitro characterization of 2-PS led to the identification of active site variants with improved kinetic properties relative to wildtype...
February 19, 2018: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/29456710/mechanism-of-apoptosis-induction-associated-with-erk1-2-upregulation-via-goniothalamin-in-melanoma-cells
#15
Suphakorn Tangchirakhaphan, Sukanda Innajak, Sirinun Nilwarangkoon, Nudjaree Tanjapatkul, Wilawan Mahabusrakum, Ramida Watanapokasin
The present study aimed to investigate the effect of goniothalamin on apoptosis induction in the A375 melanoma cell line. Melanoma is a type of skin cancer with increased prevalence and no potential standard treatment. Goniothalamin is a plant, bioactive styrly-lactone, which has various bioactivities including anti-microbial, anti-inflammatory and anti-cancer. Apoptosis induction by goniothalamin has been studied in numerous cancer cell lines, however not in the melanoma cell line A375. The results of the MTT assay demonstrated that goniothalamin induced anti-proliferation in a dose dependent manner...
March 2018: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/29455731/rapid-screening-and-identification-of-sesquiterpene-lactones-in-kudiezi-injection-based-on-high-performance-liquid-chromatography-coupled-with-linear-ion-trap-orbitrap-mass-spectrometry
#16
Rong-Rong Liu, Xiu-Ping Zhang, Fang Wang, Zhan-Peng Shang, Fei Wang, Ying Liu, Jian-Qiu Lu, Jia-Yu Zhang
Sesquiterpene lactones are considered as the major active compounds in Kudiezi injection in virtue of their special structures and activities. Herein, an analytical method was developed for rapid screening and identification of sesquiterpene lactones in Kudiezi injection using high-performance liquid chromatography coupled with linear ion trap-orbitrap mass spectrometry (HPLC-LTQ-Orbitrap) in negative ion mode. First, two sesquiterpene lactone reference standards were analyzed to obtain their characteristic ESI-MS/MS fragmentation patterns...
February 2018: Chinese Journal of Natural Medicines
https://www.readbyqxmd.com/read/29454692/from-milk-to-cheese-evolution-of-flavor-fingerprint-of-milk-cream-curd-whey-ricotta-scotta-and-ripened-cheese-obtained-during-summer-alpine-pasture
#17
M Bergamaschi, G Bittante
The role of each step of cheese and ricotta making in development of flavor of cheese and other dairy products is not yet well known. The objectives of this study were to characterize volatile organic compounds (VOC) in cheese and ricotta making with bulk milk from cows grazing in a highland area and to evaluate their evolution in the various dairy products and by-products obtained during the production processes. A group of 148 cows was grazed day and night on pasture from June to September. A total of 7 cheese-making sessions were carried out using the bulk milk collected every 2 wk during summer pasturing according to the artisanal procedure used for Malga cheese production...
February 14, 2018: Journal of Dairy Science
https://www.readbyqxmd.com/read/29454618/natural-small-molecule-bigelovin-suppresses-orthotopic-colorectal-tumor-growth-and-inhibits-colorectal-cancer-metastasis-via-il6-stat3-pathway
#18
Mingyue Li, Grace Gar-Lee Yue, Li-Hua Song, Mao-Bo Huang, Julia Kin-Ming Lee, Stephen Kwok-Wing Tsui, Kwok-Pui Fung, Ning-Hua Tan, Clara Bik-San Lau
Bigelovin, a sesquiterpene lactone, has been demonstrated to induce apoptosis, inhibit inflammation and angiogenesis in vitro, but its potential anti-metastatic activity remains unclear. In the present study, two colon cancer mouse models, orthotopic tumor allografts and experimental metastatic models were utilized to investigate the progression and metastatic spread of colorectal cancer after bigelovin treatments. Results showed that bigelovin (intravenous injection; 0.3-3 mg/kg) significantly suppressed tumor growth and inhibited liver/lung metastasis with modulation of tumor microenvironment (e...
February 15, 2018: Biochemical Pharmacology
https://www.readbyqxmd.com/read/29448055/proteomic-characterization-of-withaferin-a-targeted-protein-networks-for-the-treatment-of-monoclonal-myeloma-gammopathies
#19
Martin Dom, Fritz Offner, Wim Vanden Berghe, Xaveer Van Ostade
Withaferin A (WA), a natural steroid lactone from the plant Withania somnifera, is often studied because of its antitumor properties. Although many in vitro and in vivo studies have been performed, the identification of Withaferin A protein targets and its mechanism of antitumor action remain incomplete. We used quantitative chemoproteomics and differential protein expression analysis to characterize the WA antitumor effects on a multiple myeloma cell model. Identified relevant targets were further validated by Ingenuity Pathway Analysis and Western blot and indicate that WA targets protein networks that are specific for monoclonal gammopathy of undetermined significance (MGUS) and other closely related disorders, such as multiple myeloma (MM) and Waldenström macroglobulinemia (WM)...
February 12, 2018: Journal of Proteomics
https://www.readbyqxmd.com/read/29446957/vitamin-catalysis-direct-photocatalytic-synthesis-of-benzocoumarins-via-riboflavin-mediated-electron-transfer
#20
Tobias Morack, Jan B Metternich, Ryan Gilmour
An operationally simple protocol is disclosed to facilitate entry to benzo-3,4-coumarins directly from biaryl carboxylic acids without the need for substrate prefunctionalization. Complementary to classic lactonization strategies, this disconnection relies on the oxidation competence of photoactivated (-)-riboflavin (vitamin B 2 ) to generate the heterocyclic core via photoinduced single electron transfer. Collectively, the inexpensive nature of the catalyst, ease of execution, and absence of external metal additives are a convincing endorsement for the incorporation of simple vitamins in contemporary catalysis...
February 15, 2018: Organic Letters
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