keyword
MENU ▼
Read by QxMD icon Read
search

PKS

keyword
https://www.readbyqxmd.com/read/28213660/evidence-of-an-unidentified-extracellular-heat-stable-factor-produced-by-lysobacter-enzymogenes-oh11-that-degrade-fusarium-graminearum-ph1-hyphae
#1
Benard Omondi Odhiambo, Gaoge Xu, Guoliang Qian, Fengquan Liu
Lysobacter enzymogenes OH11 produces heat-stable antifungal factor (HSAF) and lytic enzymes possessing antifungal activity. This study bio-prospected for other potential antifungal factors besides those above. The cells and extracellular metabolites of L. enzymogenes OH11 and the mutants ΔchiA, ΔchiB, ΔchiC, Δclp, Δpks, and ΔpilA were examined for antifungal activity against Fusarium graminearum PH1, the causal agent of Fusarium head blight (FHB). Results evidenced that OH11 produces an unidentified extracellular heat-stable degrading metabolite (HSDM) that exhibit degrading activity on F...
February 17, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28212383/novel-molecular-structural-and-evolutionary-characteristics-of-the-phosphoketolases-from-bifidobacteria-and-coriobacteriales
#2
Radhey S Gupta, Anish Nanda, Bijendra Khadka
Members from the order Bifidobacteriales, which include many species exhibiting health promoting effects, differ from all other organisms in using a unique pathway for carbohydrate metabolism, known as the "bifid shunt", which utilizes the enzyme phosphoketolase (PK) to carry out the phosphorolysis of both fructose-6-phosphate (F6P) and xylulose-5-phosphate (X5P). In contrast to bifidobacteria, the PKs found in other organisms (referred to XPK) are able to metabolize primarily X5P and show very little activity towards F6P...
2017: PloS One
https://www.readbyqxmd.com/read/28211202/role-of-modular-polyketide-synthases-in-the-production-of-polyether-ladder-compounds-in-ciguatoxin-producing-gambierdiscus-polynesiensis-and-g-excentricus-dinophyceae
#3
Gurjeet S Kohli, Katrina Campbell, Uwe John, Kirsty F Smith, Santiago Fraga, Lesley L Rhodes, Shauna A Murray
Gambierdiscus, a benthic dinoflagellate, produces ciguatoxins that cause the human illness Ciguatera. Ciguatoxins are polyether ladder compounds that have a polyketide origin, indicating that polyketide synthases (PKS) are involved in their production. We sequenced transcriptomes of G. excentricus and G. polynesiensis and found 264 contigs encoding single domain ketoacyl synthases (KS; G. excentricus: 106, G. polynesiensis: 143) and ketoreductases (KR; G. excentricus: 7, G. polynesiensis: 8) with sequence similarity to type I PKSs, as reported in other dinoflagellates...
February 17, 2017: Journal of Eukaryotic Microbiology
https://www.readbyqxmd.com/read/28185457/the-bengamides-a-mini-review-of-natural-sources-analogues-biological-properties-biosynthetic-origins-and-future-prospects
#4
Kimberly N White, Karen Tenney, Phillip Crews
This review focuses entirely on the natural bengamides and selected synthetic analogues that have inspired decades of research. Bengamide A was first reported in 1986 from the sponge Jaspis cf. coriacea, and bengamide-containing sponges have been gathered from many biogeographic sites. In 2005, a terrestrial Gram-negative bacterium, Myxococcus virescens, was added as a source for bengamides. Biological activity data using varying bengamide-based scaffolds has enabled fine-tuning of structure-activity relationships...
February 10, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28166842/seroprevalence-of-cytomegalovirus-infection-in-france-in-2010
#5
D Antona, A Lepoutre, L Fonteneau, C Baudon, F Halftermeyer-Zhou, Y LE Strat, D Lévy-Bruhl
Cytomegalovirus (CMV) infection remains the leading cause of congenital virus infection in developed countries. Measuring the national prevalence of this infection, especially among women of childbearing age, is of great value to estimate the risk of congenital CMV infection, as well as to identify risk groups that should be targeted for behavioural interventions and/or vaccination once a CMV vaccine finally becomes available. In order to fulfil these objectives, a seroprevalence survey was conducted in 2010, using a nationally representative, population-based sample of 2536 people aged between 15 and 49 years, living in metropolitan France and attending private microbiological laboratories for blood testing...
February 7, 2017: Epidemiology and Infection
https://www.readbyqxmd.com/read/28137838/hydroxyl-regioisomerization-of-anthracycline-catalyzed-by-a-four-enzyme-cascade
#6
Zhuan Zhang, Yu-Kang Gong, Qiang Zhou, Yu Hu, Hong-Min Ma, Yong-Sheng Chen, Yasuhiro Igarashi, Lifeng Pan, Gong-Li Tang
Ranking among the most effective anticancer drugs, anthracyclines represent an important family of aromatic polyketides generated by type II polyketide synthases (PKSs). After formation of polyketide cores, the post-PKS tailoring modifications endow the scaffold with various structural diversities and biological activities. Here we demonstrate an unprecedented four-enzyme-participated hydroxyl regioisomerization process involved in the biosynthesis of kosinostatin. First, KstA15 and KstA16 function together to catalyze a cryptic hydroxylation of the 4-hydroxyl-anthraquinone core, yielding a 1,4-dihydroxyl product, which undergoes a chemically challenging asymmetric reduction-dearomatization subsequently acted by KstA11; then, KstA10 catalyzes a region-specific reduction concomitant with dehydration to afford the 1-hydroxyl anthraquinone...
January 30, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28131654/effects-of-udp-glucuronosyltransferase-ugt-polymorphisms-on-the-pharmacokinetics-of-febuxostat-in-healthy-chinese-volunteers
#7
Meihua Lin, Jian Liu, Huili Zhou, Minglan Wu, Duo Lv, Yujie Huang, Yunliang Zheng, Jianzhong Shentu, Lihua Wu
The pharmacokinetics (PKs) of febuxostat varies among individuals, while the main causes are still unknown. We investigated whether the polymorphisms of UGT1A1 and UGT1A3 played an important role in the disposition of the drug after oral administration of febuxostat tablet in Chinese subjects. A total of 42 healthy subjects were from two previous independent clinical bioequivalence (BE) trials of febuxostat, in which the same reference formulation (ULORIC(®) tablet, 80 mg) was taken, and thus the PK data were combined for the evaluation of pharmacogenomic effect on febuxostat PKs...
August 20, 2016: Drug Metabolism and Pharmacokinetics
https://www.readbyqxmd.com/read/28129295/asymptomatic-infection-in-decompensated-full-thickness-corneal-grafts-referred-for-repeat-penetrating-keratoplasty
#8
Yoav Nahum, Pia Leon, Benedetta Azzurra Ricci-Filipovic, Davide Camposampiero, Diego Ponzin, Massimo Busin
PURPOSE: We report a case series of asymptomatic infections affecting failed corneal grafts in patients referred for repeat penetrating keratoplasty (PK). METHODS: In this retrospective, noncomparative, interventional case series, we reviewed the medical records of all repeat PK procedures performed at Villa Serena-Villa Igea private Hospitals (Forlì, Italy) between January 2011 and March 2016. Specifically, preoperative and postoperative slit-lamp examinations, and the results of histological and bacteriological examinations, were noted...
January 26, 2017: Cornea
https://www.readbyqxmd.com/read/28128554/discovery-of-c-glycosylpyranonaphthoquinones-in-streptomyces-sp-mbt76-by-a-combined-nmr-based-metabolomics-and-bioinformatics-workflow
#9
Changsheng Wu, Chao Du, Koji Ichinose, Young Hae Choi, Gilles P van Wezel
Mining of microbial genomes has revealed that actinomycetes harbor far more biosynthetic potential for bioactive natural products than anticipated. Activation of (cryptic) biosynthetic gene clusters and identification of the corresponding metabolites has become a focal point for drug discovery. Here, we applied NMR-based metabolomics combined with bioinformatics to identify novel C-glycosylpyranonaphthoquinones in Streptomyces sp. MBT76 and to elucidate the biosynthetic pathway. Following activation of the cryptic qin gene cluster for a type II polyketide synthase (PKS) by constitutive expression of its pathway-specific activator, bioinformatics coupled to NMR profiling facilitated the chromatographic isolation and structural elucidation of qinimycins A-C (1-3)...
January 27, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28128495/biocatalytic-total-synthesis-of-ikarugamycin
#10
Christian Greunke, Anna Glöckle, Janine Antosch, Tobias A M Gulder
Nature provides an inexhaustible diversity of small organic molecules with beautiful molecular architectures that have strong and selective inhibitory activities. However, this tremendous biomedical potential often remains inaccessible, as the structural complexity of natural products can render their synthetic preparation extremely challenging. This problem is addressable by harnessing the biocatalytic procedures evolved by nature. In this work, we present an enzymatic total synthesis of ikarugamycin. The use of an iterative PKS/NRPS machinery and two reductases has allowed the construction of 15 carbon-carbon and 2 carbon-nitrogen bonds in a biocatalytic one-pot reaction...
January 27, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28119518/molecular-beacons-to-identify-gifted-microbes-for-genome-mining
#11
Richard H Baltz
Microbial genome mining is a promising technology that is revitalizing natural product discovery. It is now well documented that many bacteria with large genomes, particularly actinomycetes, encode many more secondary metabolites (SMs) than was previously known from their expressed secondary metabolomes. There are effective bioinformatics tools for counting the numbers and nature of SMs, and determining the total coding capacity from finished microbial genomes. However, these methods do not translate well to draft genomes, particularly for large SM gene clusters that contain nonribosomal peptide synthetase (NRPS) or type I polyketide synthase (PKS-I) mega-genes which are prone to fragmentation and misassembly...
January 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/28109060/morphine-pharmacodynamics-in-mechanically-ventilated-preterm-neonates-undergoing-endotracheal-suctioning
#12
P A Välitalo, Ehj Krekels, M van Dijk, Shp Simons, D Tibboel, Caj Knibbe
To date, morphine pharmacokinetics (PKs) are well quantified in neonates, but results about its efficacy are ambiguous. This work presents an analysis of a previously published study on pain measurements in mechanically ventilated preterm neonates who received either morphine or placebo to improve comfort during invasive ventilation. The research question was whether morphine reduces the pain associated with endotracheal or nasal suctioning before, during, and after suctioning. Because these neonates cannot verbalize their pain levels, pain was assessed on the basis of several validated pain measurement instruments (i...
January 21, 2017: CPT: Pharmacometrics & Systems Pharmacology
https://www.readbyqxmd.com/read/28106709/systemic-pharmacokinetics-and-pharmacodynamics-of-intravitreal-aflibercept-bevacizumab-and-ranibizumab
#13
Robert L Avery, Alessandro A Castellarin, Nathan C Steinle, Dilsher S Dhoot, Dante J Pieramici, Robert See, Stephen Couvillion, Maʼan A Nasir, Melvin D Rabena, Mauricio Maia, Sherri Van Everen, Kha Le, William D Hanley
PURPOSE: To evaluate the systemic pharmacokinetics (PKs) of aflibercept, bevacizumab, and ranibizumab in patients with neovascular age-related macular degeneration (AMD), diabetic macular edema (DME), or retinal vein occlusion (RVO). METHODS: Prospective, open-label, nonrandomized clinical trial of patients with AMD, DME, or RVO who were antivascular endothelial growth factor (VEGF) naïve or had not received anti-VEGF for ≥4 months. Patients received 3 monthly intravitreal injections of aflibercept 2...
January 18, 2017: Retina
https://www.readbyqxmd.com/read/28106181/in-vitro-kinetic-study-of-the-squalestatin-tetraketide-synthase-dehydratase-reveals-the-stereochemical-course-of-a-fungal-highly-reducing-polyketide-synthase
#14
Emma Liddle, Alan Scott, Li-Chen Han, David Ivison, Thomas J Simpson, Christine L Willis, Russell J Cox
Six potential diketide substrates for the squalestatin tetraketide synthase (SQTKS) dehydratase (DH) domain were synthesised as N-acetyl cysteamine thiolesters (SNAC) and tested in kinetic assays as substrates with an isolated DH domain. 3R-3-hydroxybutyryl SNAC 3R-16 was turned over by the enzyme, but its enantiomer was not. Of the four 2-methyl substrates only 2R,3R-2-methyl-3-hydroxybutyryl SNAC 2R,3R-8 was a substrate. Combined with stereochemical information from the isolated SQTKS enoyl reductase (ER) domain, our results provide a near complete stereochemical description of the first cycle of beta-modification reactions of a fungal highly reducing polyketide synthase (HR-PKS)...
January 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28103677/inversion-of-extender-unit-selectivity-in-the-erythromycin-polyketide-synthase-by-acyltransferase-domain-engineering
#15
Irina Koryakina, Christian Kasey, John B McArthur, Andrew N Lowell, Joseph A Chemler, Shasha Li, Douglas A Hansen, David H Sherman, Gavin J Williams
Acyltransferase (AT) domains of polyketide synthases (PKSs) select extender units for incorporation into polyketides and dictate large portions of the structures of clinically relevant natural products. Accordingly, there is significant interest in engineering the substrate specificity of PKS ATs in order to site-selectively manipulate polyketide structure. However, previous attempts to engineer ATs have yielded mutant PKSs with relaxed extender unit specificity, rather than an inversion of selectivity from one substrate to another...
20, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28102686/one-pot-enzymatic-total-synthesis-of-presteffimycinone-an-early-intermediate-of-the-anthracycline-antibiotic-steffimycin-biosynthesis
#16
Guojun Wang, Jing Chen, Haining Zhu, Jürgen Rohr
Early acting cyclases play critical roles in programming the polyketide biosynthesis toward certain, distinguished scaffolds. Starting from acetyl-CoA and malonyl-CoA, a one-pot enzymatic total synthesis of an anthracyclinone scaffold, presteffimycinone, was achieved by mixing polyketide synthase (PKS) and early post-PKS enzymes from the biosynthetic pathways of three different types of type II-PKS driven anticancer antibiotics, namely, the mithramycin (aureolic acid-type), gilvocarcin (rearranged angucycline-type), and steffimycin (anthracycline) pathways...
January 19, 2017: Organic Letters
https://www.readbyqxmd.com/read/28098952/solving-the-puzzle-of-one-carbon-loss-in-ripostatin-biosynthesis
#17
Chengzhang Fu, David Auerbach, Yanyan Li, Ullrich Scheid, Eva Luxenburger, Ronald Garcia, Herbert Irschik, Rolf Müller
Ripostatin is a promising antibiotic that inhibits RNA polymerase by binding to a novel binding site. In this study, the characterization of the biosynthetic gene cluster of ripostatin, which is a peculiar polyketide synthase (PKS) hybrid cluster encoding cis- and trans-acyltransferase PKS genes, is reported. Moreover, an unprecedented mechanism for phenyl acetic acid formation and loading as a starter unit was discovered. This phenyl-C2 unit is derived from phenylpyruvate (phenyl-C3) and the mechanism described herein explains the mysterious loss of one carbon atom in ripostatin biosynthesis from the phenyl-C3 precursor...
January 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28098949/identification-of-cellular-targets-involved-in-cardiac-failure-caused-by-pki-in-oncology-an-approach-combining-pharmacovigilance-and-pharmacodynamics
#18
E Patras de Campaigno, E Bondon-Guitton, G Laurent, F Montastruc, J L Montastruc, M Lapeyre-Mestre, F Despas
AIMS: To evaluate the risk of cardiac failure (CF) of 15 anticancer protein kinase inhibitors (PKIs) through a case/non-case analysis and to identify which PK(s) and pathways are involved in PKI-induced CF. METHODS: To evaluate the risk of CF, adjusted reporting odds ratios (aRORs) were calculated for the 15 anticancer PKIs in the WHO safety report database (VigiBase®). We realised a literature review to identify 21 PK possibly involved in CF caused by PKIs. Pearson's correlation coefficients (r) between aROR and affinity data of the 15 PKIs for the 21 PKs were calculated to identify the cellular target most likely involved in PKI-induced CF...
January 18, 2017: British Journal of Clinical Pharmacology
https://www.readbyqxmd.com/read/28096394/elucidating-the-mechanism-of-fluorinated-extender-unit-loading-for-improved-production-of-fluorine-containing-polyketides
#19
Omer Ad, Benjamin W Thuronyi, Michelle C Y Chang
Polyketides are a large family of bioactive natural products synthesized by polyketide synthase (PKS) enzyme complexes predominantly from acetate and propionate. Given the structural diversity of compounds produced using these two simple building blocks, there has been longstanding interest in engineering the incorporation of alternative extender units. We have been investigating the mechanism of fluorinated monomer insertion by three of the six different modules of the PKS involved in erythromycin biosynthesis (6-deoxyerythronolide B synthase, DEBS) to begin understanding the contribution of different steps, such as enzyme acylation, transacylation, C-C bond formation, and chain transfer, to the overall selectivity and efficiency of this process...
January 31, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28095865/engineered-biosynthesis-of-milbemycins-in-the-avermectin-high-producing-strain-streptomyces-avermitilis
#20
Myoun-Su Kim, Wan-Je Cho, Myoung Chong Song, Seong-Whan Park, Kaeun Kim, Eunji Kim, Naryeong Lee, Sang-Jip Nam, Ki-Hoon Oh, Yeo Joon Yoon
BACKGROUND: Milbemycins, produced from Streptomyces hygroscopicus subsp. aureolacrimosus and Streptomyces bingchenggensis, are 16-membered macrolides that share structural similarity with avermectin produced from Streptomyces avermitilis. Milbemycins possess strong acaricidal, insecticidal, and anthelmintic activities but low toxicity. Due to the high commercial value of the milbemycins and increasing resistance to the avermectins and their derivatives, it is imperative to develop an efficient combinatorial biosynthesis system exploiting an overproduction host strain to produce the milbemycins and novel analogs in large quantities...
January 17, 2017: Microbial Cell Factories
keyword
keyword
108064
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"