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https://www.readbyqxmd.com/read/28524195/enhanced-reactivity-and-selectivity-of-asymmetric-oxa-michael-addition-of-2-hydroxychalcones-in-carbon-confined-spaces
#1
Melad Shaikh, Kiran Kumar Atyam, Mahendra Sahu, Kalluri V S Ranganath
Carbon nanotubes (CNTs) are employed as nanoscale reaction vessels for the asymmetric oxa-Michael addition of 2'-hydroxychalcones. A systematic comparison of the catalytic activities of chiral phosphoric acid treated ferrite nanoparticles (chiral ferrites) has been studied for the synthesis of flavanones. Higher reactivity and selectivity with switching of enantiomers were observed when these chiral ferrites are inside the CNT channel.
May 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28520867/activity-of-ceftolozane-tazobactam-against-surveillance-and-problem-enterobacteriaceae-pseudomonas-aeruginosa-and-non-fermenters-from-the-british-isles
#2
David M Livermore, Shazad Mushtaq, Daniele Meunier, Katie L Hopkins, Robert Hill, Rachael Adkin, Aiysha Chaudhry, Rachel Pike, Peter Staves, Neil Woodford
Background: We assessed the activity of ceftolozane/tazobactam against consecutive isolates collected in the BSAC Bacteraemia Surveillance from 2011 to 2015 and against 'problem' isolates sent to the UK national reference laboratory from July 2015, when routine testing began. Methods: Susceptibility testing was by BSAC agar dilution with resistance mechanisms identified by PCR and interpretive reading. Results: Data were reviewed for 6080 BSAC surveillance isolates and 5473 referred organisms...
May 16, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28515629/microbial-competition-in-environmental-nosocomial-reservoirs-and-diffusion-capacity-of-oxa48-klebsiella-pneumoniae-potential-impact-on-patients-and-possible-control-methods
#3
REVIEW
R Herruzo, G Ruiz, M J Vizcaino, L Rivas, V Pérez-Blanco, M Sanchez
BACKGROUND: We have found clusters of Klebsiella pneumoniae with OXA48-carbepenemase cases in some hospital rooms, and decided to investigate whether bathroom siphons could be a reservoir for OXA48 bacteria, as occurs with K. oxytoca with other types of carbepenemases. METHODS: We evaluated the microbial competition between strains with OXA48 and VIM carbepenemases, in diluted nutrient-broth, on a slime germ-carrier. We compared the number of colonies at 5 and 10 days on the contaminated carriers with one or two strains...
March 2017: Journal of Preventive Medicine and Hygiene
https://www.readbyqxmd.com/read/28513417/carriage-of-extended-spectrum-beta-lactamase-producing-enterobacteriaceae-in-hiv-infected-children-in-zimbabwe
#4
S M S Wilmore, K Kranzer, A Williams, B Makamure, A F Nhidza, J Mayini, T Bandason, J Metcalfe, M P Nicol, I Balakrishnan, M J Ellington, N Woodford, S Hopkins, T D McHugh, R A Ferrand
BACKGROUND: Antimicrobial resistance is an emerging global health issue. Data on the epidemiology of multidrug-resistant organisms are scarce for Africa, especially in HIV-infected individuals who often have frequent contact with healthcare. We investigated the prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) carriage in stool among HIV-infected children attending an HIV outpatient department in Harare, Zimbabwe. METHODS: We recruited children who were stable on antiretroviral therapy (ART) attending a HIV clinic from August 2014 to June 2015...
May 18, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28508147/identification-of-beta-lactamases-and-beta-lactam-related-proteins-in-human-pathogenic-bacteria-using-a-computational-search-approach
#5
Aniel Jessica Leticia Brambila-Tapia, Ernesto Perez-Rueda, Humberto Barrios, Nory Omayra Dávalos-Rodríguez, Ingrid Patricia Dávalos-Rodríguez, Ernesto Germán Cardona-Muñoz, Mario Salazar-Páramo
A systematic analysis of beta-lactamases based on comparative proteomics has not been performed thus far. In this report, we searched for the presence of beta-lactam-related proteins in 591 bacterial proteomes belonging to 52 species that are pathogenic to humans. The amino acid sequences for 19 different types of beta-lactamases (ACT, CARB, CifA, CMY, CTX, FOX, GES, GOB, IMP, IND, KPC, LEN, OKP, OXA, OXY, SHV, TEM, NDM, and VIM) were obtained from the ARG-ANNOT database and were used to construct 19 HMM profiles, which were used to identify potential beta-lactamases in the completely sequenced bacterial proteomes...
May 16, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28507112/mcr-1-and-oxa-48-in-vivo-acquisition-in-kpc-producing-escherichia-coli-after-colistin-treatment
#6
Racha Beyrouthy, Frederic Robin, Aude Lessene, Igor Lacombat, Laurent Dortet, Thierry Naas, Valérie Ponties, Richard Bonnet
The spread of mcr-1-encoding plasmids into carbapenem-resistant Enterobacteriaceae raises concerns about the emergence of untreatable bacteria. We report the acquisition of mcr-1 in a carbapenem- resistant E. coli after a 3-week course of colistin in a patient repatriated to France from Portugal. Whole-genome sequencing revealed that the KPC-producing E. coli strain acquired two plasmids, an IncL OXA-48-encoding plasmid and an IncX4 mcr-1-encoding plasmid. This is the first report of mcr-1 in carbapenemase-encoding bacteria in France...
May 15, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28503354/mechanism-of-the-p450-catalyzed-oxidative-cyclization-in-the-biosynthesis-of-griseofulvin
#7
Jessica M Grandner, Ralph A Cacho, Yi Tang, K N Houk
Griseofulvin is an anti-fungal agent which has recently been determined to have potential anti-viral and anti-cancer applications. The role of specific enzymes involved in the biosynthesis of this natural product has previously been determined, but the mechanism by which a p450, GsfF, catalyzes the key oxidative cyclization of griseophenone B remains unknown. Using density functional theory (DFT), we have determined the mechanism of this oxidation that forms the oxa-spiro core of griseofulvin. Computations show GsfF preferentially performs two sequential phenolic O-H abstractions rather than epoxidation to form an arene oxide intermediate...
July 1, 2016: ACS Catalysis
https://www.readbyqxmd.com/read/28501431/lipase-catalyzed-kinetic-resolution-as-key-step-in-the-synthesis-of-enantiomerically-pure-%C3%AF-ligands-with-2-benzopyran-structure
#8
Inga Knappmann, Kirstin Lehmkuhl, Jens Köhler, Dirk Schepmann, Martin Giera, Franz Bracher, Bernhard Wünsch
In order to obtain enantiomerically pure σ1 receptor ligands with a 2-benzopyran scaffold an Oxa-Pictet-Spengler reaction with the enantiomerically pure 2-phenylethanol derivatives (R)-4 and (S)-4 was envisaged. The kinetic resolution of racemic alcohol (±)-4 using Amano Lipase PS-C II and isopropenyl acetate in tert-butyl methyl ether led to the (R)-configured alcohol (R)-4 in 42% yield with an enantiomeric excess of 99.6%. The (S)-configured alcohol (S)-4 was obtained by Amano Lipase PS-C II catalyzed hydrolysis of enantiomerically enriched acetate (S)-5 (76...
April 30, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28501193/immunoaffinity-chromatography-combined-with-tandem-mass-spectrometry-a-new-tool-for-the-selective-capture-and-analysis-of-brassinosteroid-plant-hormones
#9
Jana Oklestkova, Danuše Tarkowská, Luděk Eyer, Tomáš Elbert, Aleš Marek, Zora Smržová, Ondřej Novák, Milan Fránek, Vladimir N Zhabinskii, Miroslav Strnad
Brassinosteroids (BRs) are plant-specific steroid hormones that play essential roles in the regulation of many important physiological processes in plant life. Their extremely low concentrations (~pmoles/g FW) in plant tissue and huge differences in polarity of individual members within the BR family hamper their detection and quantification. To address this problem, an immunoaffinity sorbent with broad specificity and high capacity for different BR metabolites containing a monoclonal antibody (mAb) against a BR spacer (20S)-2α,3α-dihydroxy-7-oxa-7α-homo-5α-pregnane-6-one-20 carboxylic acid (BR4812) was used for the rapid and highly selective isolation of endogenous BRs containing a 2α,3α-diol in ring A from minute plant samples...
August 1, 2017: Talanta
https://www.readbyqxmd.com/read/28498807/knockdown-of-pkm2-and-gls1-expression-can-significantly-reverse-oxaliplatin-resistance-in-colorectal-cancer-cells
#10
Wei-Qun Lu, Ying-Ying Hu, Xiao-Ping Lin, Wei Fan
Clinical treatment for colorectal cancer (CRC) thus far encounters a huge challenge due to oxaliplatin-resistance. As crucial rate-limiting enzymes in aerobic glycolysis and glutaminolysis, pyruvate kinase M2 type (PKM2) and kidney-type glutaminase (GLS1) are proposed to carry important implications in colorectal carcinogenesis and drug-resistance. This study aimed to explore the possible association of oxaliplatin-resistance with aerobic glycolysis/glutaminolysis indexed by PKM2/GLS1 expression. PKM2 and GLS1 expression was quantified by polymerase chain reaction (PCR) and Western blot techniques in CRC cell lines...
April 24, 2017: Oncotarget
https://www.readbyqxmd.com/read/28495384/medicinal-chemistry-of-antischistosomal-drugs-praziquantel-and-oxamniquine
#11
REVIEW
Vinícius Barros Ribeiro da Silva, Bruna Rafaella Koresch Leiva Campos, Jamerson Ferreira de Oliveira, Jean-Luc Decout, Maria do Carmo Alves de Lima
Neglected tropical diseases (NTDs) are a group of diseases that, besides prevailing in poverty conditions, contribute to the maintenance of social inequality, being a strong barrier to a country development. Schistosomiasis, a NTD, is a tropical and subtropical disease caused by the trematode Schistosoma mansoni (Africa, Middle East, Caribbean, Brazil, Venezuela, Suriname), japonicum (China, Indonesia, the Philippines), mekongi (several districts of Cambodia and the Lao People's Democratic Republic), intercalatum and guianensis (areas of tropical rainforests in Central Africa) and hematobium (Middle East Africa, Corsica, France) whose adult forms inhabit the mesenteric vessels of the host, while the intermediate forms are found in the aquatic gastropod snails of the genus Biomphalaria...
April 27, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28492753/effect-of-erosion-abrasion-challenge-on-the-dentin-tubule-occlusion-using-different-desensitizing-agents
#12
Gabriela D Canali, Rodrigo N Rached, Rui F Mazur, Evelise M Souza
The aim of the study was to evaluate dentinal tubule occlusion, measuring the dentin permeability (Lp) and using different desensitizing agents before and after abrasive/erosive challenge. Dentin discs from 42 healthy human third molars were obtained. Minimum Lp was measured after a smear layer simulation using #600 SiC paper and maximum Lp after an immersion in 0.5 M EDTA. The specimens were treated with different desensitizers: two varnishes (Clinpro XT Varnish-CV, Fluor Protector-FP), a paste (Desensibilize Nano P-NP) and a gel (Oxa Gel-OG)...
March 2017: Brazilian Dental Journal
https://www.readbyqxmd.com/read/28486994/the-emergence-of-a-novel-sequence-type-of-mdr-acinetobacter-baumannii-from-the-intensive-care-unit-of-an-egyptian-tertiary-care-hospital
#13
Doaa Mohammad Ghaith, Mai Mahmoud Zafer, Mohamed Hamed Al-Agamy, Essam J Alyamani, Rayan Y Booq, Omar Almoazzamy
BACKGROUND AND AIM OF WORK: Acinetobacter baumannii is known for nosocomial outbreaks worldwide. In this study, we aimed to investigate the antibiotic susceptibility patterns and the clonal relationship of A. baumannii isolates from the intensive care unit (ICU) of an Egyptian hospital. METHODS: In the present study, 50 clinical isolates of multidrug resistant (MDR)-A. baumannii were obtained from patients admitted into the ICU from June to December 2015. All isolates were analyzed for antimicrobial susceptibilities...
May 10, 2017: Annals of Clinical Microbiology and Antimicrobials
https://www.readbyqxmd.com/read/28486840/molecular-characterization-of-carbapenem-resistant-enterobacteriaceae-yields-increasing-rates-of-ndm-1-carbapenemases-and-colistin-resistance-in-an-oxa-48-endemic-area
#14
Zeynep Cizmeci, Elif Aktas, Baris Otlu, Ozlem Acikgoz, Seyhan Ordekci
We aimed to characterize carbapenem-resistant isolates in a tertiary hospital in Istanbul, Turkey, high-prevelance area for OXA-48 producers. About 76 Enterobacteriaceae clinical isolates were included. Carbapenemase production was detected by Carbapenem Inactivation Method and carbapenemase genes were investigated by PCR. The clonal relationships were evaluated by AP-PCR. Nineteen Klebsiella pneumoniae isolates were colistin resistant. About 75 isolates yielded carbapenemase by CIM. 52 OXA-48, 17 NDM-1 and 2 VIM-5 carbapenemase genes were detected...
May 9, 2017: Journal of Chemotherapy
https://www.readbyqxmd.com/read/28486169/characterization-of-oxa-48-like-producing-enterobacteriaceae-isolated-from-river-water-in-algeria
#15
Rima Tafoukt, Abdelaziz Touati, Thongpan Leangapichart, Sofiane Bakour, Jean-Marc Rolain
The spread of carbapenemase-producing Enterobacteriaceae (CPE) is a significant problem for healthcare worldwide. The prevalence of carbapenem-resistant Enterobacteriaceae (CPE) in water environments in Algeria are unknown. The aim of this study was to screen for the presence of CPE isolates in the Soummam River in Bejaia, Algeria. Isolates of Enterobacteriaceae recovered from twelve samples of river water and showing reduced susceptibility to carbapenems were included in this study. The isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)...
April 30, 2017: Water Research
https://www.readbyqxmd.com/read/28485708/molecular-study-of-carbapenemase-genes-in-clinical-isolates-of-enterobacteriaceae-resistant-to-carbapenems-and-determining-their-clonal-relationship-using-pulsed-field-gel-electrophoresis
#16
Fereshteh Shahcheraghi, Mohammad Mehdi Aslani, Hassan Mahmoudi, Zahra Karimitabar, Hamid Solgi, Abbas Bahador, Mohammad Yousef Alikhani
PURPOSE: Enterobacteriaceae is a large family of Gram-negative bacteria that are considered as normal gut flora. They are the most common human pathogens. The main objective of this study was to investigate the carbapenemase genes in clinical isolates of Enterobacteriaceae resistant to carbapenem antibiotics and determine their clonal relationship using pulsed-field gel electrophoresis (PFGE). METHODOLOGY: In the present study, bacteria were isolated and identified via conventional biochemical tests and API 20NE...
May 9, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28483549/detection-of-oxa-370-directly-from-rectal-swabs-and-blood-culture-vials-using-an-immunochromatographic-assay
#17
Carolina Silva Nodari, Ana Cristina Gales, Afonso Luís Barth, Cibele Massotti Magagnin, Alexandre Prehn Zavascki, Cecília Godoy Carvalhaes
We evaluated the performance of OXA-48 K-SeT assay for detecting OXA-370 directly from spiked rectal swabs and blood culture vials. The limit of detection of this test was 10(4)UFC/mL for rectal swabs. Detection of the OXA-370-producing isolates was successfully achieved directly from positive blood culture vials independent of growing conditions.
May 5, 2017: Journal of Microbiological Methods
https://www.readbyqxmd.com/read/28482341/indigo-naturalis-ameliorates-oxazolone-induced-dermatitis-but-aggravates-colitis-by-changing-the-composition-of-gut-microflora
#18
Soichiro Adachi, Namiko Hoshi, Jun Inoue, Eiichiro Yasutomi, Takafumi Otsuka, Ramesh Dhakhwa, Zi Wang, Yuna Koo, Toshihiro Takamatsu, Yuriko Matsumura, Haruka Yamairi, Daisuke Watanabe, Makoto Ooi, Toshihito Tanahashi, Shin Nishiumi, Masaru Yoshida, Takeshi Azuma
BACKGROUND: Indigo naturalis (IND) is an herbal medicine that has been used as an anti-inflammatory agent to treat diseases including dermatitis and inflammatory bowel disease in China. However, the mechanism by which IND exerts its immunomodulatory effect is not well understood. METHODS: A murine model of dermatitis and inflammatory bowel disease, both induced by oxazolone (OXA), was treated with IND. The severity of dermatitis was evaluated based on ear thickness measurements and histological scoring...
May 9, 2017: International Archives of Allergy and Immunology
https://www.readbyqxmd.com/read/28476242/evaluation-of-the-carbapenem-inactivation-method-cim-for-detecting-carbapenemase-activity-in-enterobacteria
#19
A Aguirre-Quiñonero, M E Cano, D Gamal, J Calvo, L Martínez-Martínez
OBJECTIVES: The objective of this study was to evaluate the accuracy of the CIM test in the detection of carbapenemase activity in 124 strains of Enterobacteriaceae. METHODS: A panel of 124 previously characterized Enterobacteriaceae was tested: 77 strains producing the following carbapenemase families: KPC (n = 14), GES (n = 22), NDM (n = 19), VIM (n = 4), IMP (n = 4) and OXA-48 (n = 14) and 47 non-carbapenemase producers. For the CIM method, an active susceptibility meropenem disc was exposed to a bacterial suspension of a test strain; when a carbapenemase is produced, the antibiotic is inactivated allowing uninhibited growth of an indicator strain after overnight incubation...
March 16, 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/28475585/acinetobacter-baumannii-strains-isolated-from-patients-in-intensive-care-units-in-goi%C3%A3-nia-brazil-molecular-and-drug-susceptibility-profiles
#20
Suellen Rocha Araújo Castilho, Cássia Silva de Miranda Godoy, Adriana Oliveira Guilarde, Juliana Lamaro Cardoso, Maria Cláudia Porfirio André, Ana Paula Junqueira-Kipnis, André Kipnis
Resistance to antimicrobial agents is increasing worldwide and imposes significant life-threatening risks to several different populations, especially those in intensive care units (ICUs). Bacteria can quickly develop or acquire resistance to antimicrobial drugs, and combined with their intrinsic potential to cause disease in humans, these bacteria can become deadly. Among Gram-negative bacteria, Acinetobacter baumannii is notorious as a frequent opportunistic pathogen associated with critically ill patients, and understanding the genetic basis of A...
2017: PloS One
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