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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
E Le Balc'h, C Landman, E Tauziet, L Brot, E Quevrain, D Rainteau, J-P Grill, S Thenet, P Seksik
No abstract text is available yet for this article.
February 1, 2017: Journal of Crohn's & Colitis
Yang Lu, Jianming Zeng, Binning Wu, Shunmei E, Lina Wang, Renxin Cai, Ni Zhang, Youqiang Li, Xianzhang Huang, Bin Huang, Cha Chen
Conjugation is a key mechanism for horizontal gene transfer and plays an important role in bacterial evolution, especially with respect to antibiotic resistance. However, little is known about the role of donor and recipient cells in regulation of conjugation. Here, using an Escherichia coli (SM10λπ)-Pseudomonas aeruginosa (PAO1) conjugation model, we demonstrated that deficiency of lasI/rhlI, genes associated with generation of the quorum sensing signals N-acyl homoserine lactones (AHLs) in PAO1, or deletion of the AHLs receptor SdiA in the donor SM10λπ both facilitated conjugation...
2017: Frontiers in Cellular and Infection Microbiology
Meei-Hua Lin, Jeffery Miner, John Turk, Fong-Fu Hsu
1-O-acylceramide is a new class of epidermal ceramide found in humans and mice. Here, we report ESI linear ion-trap (LIT) multiple stage mass spectrometric (MSn) approach with high resolution towards structural characterization of this lipid family isolated from mice. Molecular species desorbed as the [M + H]+ ions was subjected to LIT MS2 to yield predominately the [M + H - H2O]+ ions, followed by MS3 to cleave the 1-O-acyl residue to yield the [M + H - H2O - (1-O-fatty acid)]+ ions. The structures of the N-acyl chain and long-chain base (LCB) of the molecule were determined by MS4 on ([M + H - H2O - (1-O-fatty acid)]+) ions that yielded multiple sets of specific ions...
February 2, 2017: Journal of Lipid Research
Mateusz Daśko, Maja Przybyłowska, Janusz Rachon, Maciej Masłyk, Konrad Kubiński, Majus Misiak, Andrzej Składanowski, Sebastian Demkowicz
In the present work, we report convenient methods for the synthesis of 3-(4-aminophenyl)-coumarin-7-O-sulfamate derivatives N-acylated with fluorinated analogues of benzoic or phenylacetic acid as steroid sulfatase (STS) inhibitors. The design of these potential STS inhibitors was supported by molecular modeling techniques. Additionally, computational docking methods were used to determine the binding modes of the synthesized inhibitors and to identify potential interactions between inhibitors and amino acid residues located in the active site of STS...
January 22, 2017: European Journal of Medicinal Chemistry
Sarah J Felton, Alexandra C Kendall, Abdalla F M Almaedani, Paula Urquhart, Ann R Webb, Richard Kift, Andy Vail, Anna Nicolaou, Lesley E Rhodes
Solar ultraviolet radiation (UVR) exposure of human skin has beneficial and harmful effects on health, including impact on immune function, inflammation and reportedly mood, but these are not fully elucidated. Since the endocannabinoid system is implicated in many activities including mood alteration, our objective was to (i) determine and quantify circulating levels of a wide range of endocannabinoid and N-acyl ethanolamine (NAE) species (ii) evaluate whether these are modulated by cutaneous UVR exposures, as attained through repeated low level summer sunlight exposure...
January 31, 2017: Photochemical & Photobiological Sciences
Tomohiro Morohoshi, Niina Sato, Taro Iizumi, Airi Tanaka, Tsukasa Ikeda
Biofilm formation by bacteria is one of the main causes of fouling in industrial cooling water systems. In many gram-negative bacteria, biofilm formation is regulated by N-acyl-homoserine lactone (AHL)-mediated quorum sensing. In this study, we isolated three AHL-degrading bacteria from cooling water systems and identified them as Sphingomonas ursincola. The draft genome sequence of S. ursincola A1 revealed the presence of an AHL-degrading gene homolog, designated qsdS. The qsdS region was also amplified by PCR from the genomes of the other two S...
January 24, 2017: Journal of Bioscience and Bioengineering
Haruo Sugita, Shun Kitao, Satoshi Narisawa, Ryosuke Minamishima, Shiro Itoi
Intestinal bacteria isolated from goldfish (Carassius auratus) were identified based on 16 ribosomal RNA (rRNA) gene sequences and screened for their ability to produce N-acyl homoserine lactone (AHL), an autoinducer of the quorum sensing (QS) system. The 230 aerobes/facultative anaerobes that were isolated comprised members of the genera Aeromonas (184 isolates), Citrobacter (11), Enterobacter (2), Shewanella (28), Vagococcus (1), and Vibrio (4). Among these genera, the two most abundant species were Aeromonas veronii (163 isolates) and Shewanella xiamenensis (27)...
January 26, 2017: Folia Microbiologica
Daniel D Sanz Sharley, Jonathan M J Williams
We report a cheap and simple method for the acetylation of a variety of amines using catalytic acetic acid and either ethyl acetate or butyl acetate as the acyl source. Catalyst loadings as low as 10 mol% afforded acetamide products in excellent yields at temperatures ranging from 80-120 °C. The methodology can also be successfully applied for the synthesis of a broad range of other amides, including the formation of formamides at 20 °C.
January 26, 2017: Chemical Communications: Chem Comm
Jiayue Yang, Masanori Toyofuku, Ryosuke Sakai, Nobuhiko Nomura
Many bacteria communicate with each other through signaling molecules, a process known as cell-to-cell communication. During this process, it is important for the signaling molecules to: 1) reach the target cells; and 2) to be received by the cognate receptor. Barriers such as the presence of extracellular matrix may prevent signals from reaching their targets; however, the influence of the extracellular matrix on cell-to-cell communication has scarcely been studied. Here we demonstrate that the overproduction of an extracellular matrix, alginate, in a Pseudomonas aeruginosa mucoid variant, alters cell-to-cell communication by interfering with the response to quinolone signals while having no effect on N-acyl-L-homoserine lactones (AHLs)...
January 25, 2017: Environmental Microbiology Reports
Thomas Clamens, Thibaut Rosay, Alexandre Crépin, Teddy Grandjean, Takfarinas Kentache, Julie Hardouin, Perrine Bortolotti, Anke Neidig, Marlies Mooij, Mélanie Hillion, Julien Vieillard, Pascal Cosette, Joerg Overhage, Fergal O'Gara, Emeline Bouffartigues, Alain Dufour, Sylvie Chevalier, Benoit Guery, Pierre Cornelis, Marc G J Feuilloley, Olivier Lesouhaitier
We have previously shown that the eukaryotic C-type natriuretic peptide hormone (CNP) regulates Pseudomonas aeruginosa virulence and biofilm formation after binding on the AmiC sensor, triggering the amiE transcription. Herein, the involvement of the aliphatic amidase AmiE in P. aeruginosa virulence regulation has been investigated. The proteome analysis of an AmiE over-producing strain (AmiE(+)) revealed an expression change for 138 proteins, including some that are involved in motility, synthesis of quorum sensing compounds and virulence regulation...
January 24, 2017: Scientific Reports
Thomas Tørring, Stephanie R Shames, Wooyoung Cho, Craig R Roy, Jason Crawford
Legionella pneumophila, the causative agent of Legionnaire's disease, is a Gram-negative Gammaproteobacterial pathogen that infects and intracellularly replicates in a variety of protozoa and in human macrophages. L. pneumophila encodes an orphan biosynthetic gene cluster (BGC) that contains isocyanide-associated biosynthetic genes and is upregulated during infection. Because isocyanide-functionalized metabolites are known to harbor invertebrate innate immunosuppressive activities in bacterial pathogen-insect interactions, we used pathway-targeted molecular networking and tetrazine-based chemoseletive ligation chemistry to characterize the metabolites from the orphan pathway in L...
January 23, 2017: Chembiochem: a European Journal of Chemical Biology
Mathias Gallique, Victorien Decoin, Corinne Barbey, Thibaut Rosay, Marc G J Feuilloley, Nicole Orange, Annabelle Merieau
Type VI secretion systems (T6SSs) are widespread in Gram-negative bacteria, including Pseudomonas. These macromolecular machineries inject toxins directly into prokaryotic or eukaryotic prey cells. Hcp proteins are structural components of the extracellular part of this machinery. We recently reported that MFE01, an avirulent strain of Pseudomonas fluorescens, possesses at least two hcp genes, hcp1 and hcp2, encoding proteins playing important roles in interbacterial interactions. Indeed, P. fluorescens MFE01 can immobilise and kill diverse bacteria of various origins through the action of the Hcp1 or Hcp2 proteins of the T6SS...
2017: PloS One
Theresa Fischer, Qui-Nhi Duong, Olga García Mancheño
The first enantioselective synthesis of chiral heterocyclic α-amino phosphonates by nucleophilic dearomatization of quinolines and pyridines using an anion-binding organocatalysis approach is described. Chiral tetrakistriazoles were employed as efficient hydrogen-bond donor catalysts by the formation of a chiral close ion-pair with the in situ formed N-acyl salts with Troc-chloride and subsequent treatment with various phosphorus nucleophiles, such as silyl protected dialkyl phosphites and trialkylphosphites...
January 23, 2017: Chemistry: a European Journal
Jae-Myung Yoo, Bo Dam Lee, Dai-Eun Sok, Jin Yuel Ma, Mee Ree Kim
N-acetyl serotonin (NAS) as a melatonin precursor has neuroprotective actions. Nonetheless, it is not clarified how NAS protects neuronal cells against oxidative stress. Recently, we have reported that N-palmitoyl serotonins possessed properties of antioxidants and neuroprotection. Based on those, we hypothesized that NAS, a N-acyl serotonin, may have similar actions in oxidative stress-induced neuronal cells, and examined the effects of NAS based on in vitro and in vivo tests. NAS dose-dependently inhibited oxidative stress-induced cell death in HT-22 cells...
January 6, 2017: Redox Biology
Junguo Wu, Canjun Zhu, Liusong Yang, Zhonggang Wang, Lina Wang, Songbo Wang, Ping Gao, Yongliang Zhang, Qingyan Jiang, Xiaotong Zhu, Gang Shu
N-Acyl amino acids (NAAAs) are conjugate products of fatty acids and amino acids, which are available in animal-derived food. We compared the effects of N-arachidonoylglycine (NAGly), N-arachidonoylserine (NASer), and N-oleoylglycine (OLGly) on in vivo food intake and in vitro [Ca(2+)]i of Agouti-related protein (AgRP) neurons to identify the role of these compounds in energy homeostasis. Hypothalamic neuropeptide expression and anxiety behavior in response to OLGly were also tested. To further identify the underlying mechanism of OLGly on food intake, we first detected the expression level of potential OLGly receptors...
January 30, 2017: Journal of Agricultural and Food Chemistry
Utpal Bose, Catharine A Ortori, Sarir Sarmad, David A Barrett, Amitha K Hewavitharana, Mark P Hodson, John A Fuerst, P Nicholas Shaw
The structures of acyl homoserine lactone (AHL) compounds and their quantification was accomplished using an integrated liquid chromatography-mass spectrometry approach. The precursor and product ions, along with retention times of peaks, were searched against an in-house database of AHLs and structures confirmed by accurate mass and by comparison with authentic AHL standards. The two compounds, N-(3-oxodecanoyl)-L-homoserine lactone and N-(3-oxododecanoyl)-L-homoserine lactone were characterised and quantified in Salinispora sp...
January 12, 2017: FEMS Microbiology Letters
Arun Suneja, Rajshekhar A Unhale, Vinod K Singh
An efficient route to pharmacologically interesting isoindolinone-based α-amino phosphonates is described via asymmetric hydrophosphonylation of in situ generated ketimines catalyzed by BINOL-derived phosphoric acid. The reaction proceeds smoothly at ambient temperature affording a variety of α-amino phosphonates with a quaternary stereogenic center embedded in isoindolinone motif in high yields with excellent enantiomeric ratios (up to 98.5:1.5 er). Several interesting transformations of the products into valuable synthetic intermediates are also depicted...
January 11, 2017: Organic Letters
Ravindra S Phatake, Venkannababu Mullapudi, Vivek C Wakchaure, Chepuri V Ramana
The possibility of fluoride-mediated selective dephosphonylation of α-diazo-β-carbonyl phosphonates such as the Ohira-Bestmann reagent has been proposed and executed. The resulting α-diazocarbonyl intermediates undergo a (3 + 2)-cycloaddition at room temperature with conjugated olefins and benzynes. Interestingly, under the current conditions, the resulting cycloaddition products underwent either N-acylation (with excess α-diazo-β-carbonyl phosphonates) or Michael addition (with conjugated olefins).
December 30, 2016: Organic Letters
Andrew J Mitchell, Noah P Dunham, Jonathan A Bergman, Bo Wang, Qin Zhu, Wei-Chen Chang, Xinyu Liu, Amie K Boal
Enzymatic installation of chlorine/bromine into unactivated carbon centers provides a versatile, selective, and environmentally friendly alternative to chemical halogenation. Iron(II) and 2-(oxo)-glutarate (Fe(II)/2OG)-dependent halogenases are powerful biocatalysts that are capable of cleaving aliphatic C-H bonds to introduce useful functional groups, including halogens. Using the structure of the Fe/2OG halogenase, WelO5, in complex with its small molecule substrate, we identified a similar N-acyl amino acid hydroxylase, SadA, and reprogrammed it to halogenate its substrate, thereby generating a new chiral haloalkyl center...
January 11, 2017: Biochemistry
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