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https://www.readbyqxmd.com/read/28535042/dudawalamides-a-d-antiparasitic-cyclic-depsipeptides-from-the-marine-cyanobacterium-moorea-producens
#1
Jehad Almaliti, Karla L Malloy, Evgenia Glukhov, Carmenza Spadafora, Marcelino Gutiérrez, William H Gerwick
A family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A-D (1-4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A-D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey's analysis, chiral-phase GCMS, and chiral-phase HPLC...
May 23, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28529817/coordinated-and-iterative-enzyme-catalysis-in-fungal-polyketide-biosynthesis
#2
Leibniz Hang, Nicholas Liu, Yi Tang
Fungal polyketides are natural products with great chemical diversity that exhibit a wide range of biological activity. This chemical diversity stems from specialized enzymes encoded in the biosynthetic gene cluster responsible for the natural product biosynthesis. Fungal polyketide synthases (PKS) are the megasynthases that produce the carbon scaffolds for the molecules. Subsequent downstream tailoring enzymes such as oxygenases will then further modify the organic framework. In fungi, many of these enzymes have been found to work iteratively-catalyzing multiple reactions on different sites of the substrate...
September 2, 2016: ACS Catalysis
https://www.readbyqxmd.com/read/28528545/discovery-and-biosynthesis-of-gladiolin-a-burkholderia-gladioli-antibiotic-with-promising-activity-against-mycobacterium-tuberculosis
#3
Lijiang Song, Matthew Jenner, Joleen Masschelein, Cerith Jones, Matthew J Bull, Simon R Harris, Ruben C Hartkoorn, Anthony Vocat, Isolda Romero-Canelón, Paul Coupland, Gordon Webster, Matthew Dunn, Rebecca Weiser, Christopher Paisey, Stewart T Cole, Julian Parkhill, Eshwar Mahenthiralingam, Gregory L Challis
An antimicrobial activity screen of Burkholderia gladioli BCC0238, a clinical isolate from a cystic fibrosis patient, led to the discovery of gladiolin, a novel macrolide antibiotic with potent activity against Mycobacterium tuberculosis H37Rv. Gladiolin is structurally-related to etnangien, a highly unstable antibiotic from Sorangium cellulosum that is also active against Mycobacteria. Like etnangien, gladiolin was found to inhibit RNA polymerase, a validated drug target in M. tuberculosis. However, gladiolin lacks the highly labile hexaene moiety of etnangien and was thus found to possess significantly increased chemical stability...
May 22, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28527062/the-prokineticin-system-an-interface-between-neural-inflammation-and-pain
#4
Silvia Franchi, Paola Sacerdote, Alberto Panerai
Prokineticins (PK) 1 and 2 belong to a new family of chemokines capable to interact with two different G coupled receptors: Prokineticin receptor (PKR)1 and 2. Both prokineticins and their receptors are widely distributed in different tissues and regulate several biological functions. In particular, a role of the PK system in inflammation and nociception has been established. PKRs are expressed in regions of the nervous system associated with pain and in primary sensitive neurons they colocalize with transient potential receptor vanilloid-TRPV1 providing an anatomical interaction in nociceptor sensitization...
May 2017: Neurological Sciences
https://www.readbyqxmd.com/read/28525276/chemoenzymatic-total-synthesis-and-structural-diversification-of-tylactone-based-macrolide-antibiotics-through-late-stage-polyketide-assembly-tailoring-and-c-h-functionalization
#5
Andrew N Lowell, Matthew D DeMars, Samuel T Slocum, Fengan Yu, Krithika Anand, Joseph A Chemler, Nisha Korakavi, Jennifer K Priessnitz, Sung Ryeol Park, Aaron A Koch, Pamela J Schultz, David H Sherman
Polyketide synthases (PKSs) represent a powerful catalytic platform capable of effecting multiple carbon-carbon bond forming reactions and oxidation state adjustments. We explored the functionality of two terminal PKS modules that produce the 16-membered tylosin macrocycle, using them as biocatalysts in the chemoenzymatic synthesis of tylactone and its subsequent elaboration to complete the first total synthesis of the juvenimicin, M-4365, and rosamicin classes of macrolide antibiotics via late-stage diversification...
May 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28517364/a-cryptic-pigment-biosynthetic-pathway-uncovered-by-heterologous-expression-is-essential-for-conidial-development-in-pestalotiopsis-fici
#6
Peng Zhang, Xiuna Wang, Aili Fan, Yanjing Zheng, Xingzhong Liu, Shihua Wang, Huixi Zou, Berl R Oakley, Nancy P Keller, Wen-Bing Yin
Spore pigmentation is very common in the fungal kingdom. The best studied pigment in fungi is melanin which coats the surface of single cell spores. What and how pigments function in a fungal species with multiple cell conidia is poorly understood. Here, we identified and deleted a polyketide synthase (PKS) gene PfmaE and showed that it is essential for multicellular conidial pigmentation and development in a plant endophytic fungus, Pestalotiopsis fici. To further characterize the melanin pathway, we utilized an advanced Aspergillus nidulans heterologous system for the expression of the PKS PfmaE and the Pfma gene cluster...
May 18, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28512345/phosphoproteome-analysis-reveals-phosphorylation-underpinnings-in-the-brains-of-nurse-and-forager-honeybees-apis-mellifera
#7
Gebreamlak Bezabih, Han Cheng, Bin Han, Mao Feng, Yu Xue, Han Hu, Jianke Li
The honeybee brain is a central organ in regulating wide ranges of honeybee biology, including life transition from nurse to forager bees. Knowledge is still lacking on how protein phosphorylation governs the neural activity to drive the age-specific labor division. The cerebral phosphoproteome of nurse and forager honeybees was characterized using Ti(4+)-IMAC phosphopeptide enrichment mass-spectrometry-based proteomics and protein kinases (PKs) were predicted. There were 3,077 phosphosites residing on 3,234 phosphopeptides from 1004 phosphoproteins in the nurse bees...
May 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28489314/unclassifiable-pattern-of-hypopigmentation-in-a-patient-with-mosaic-partial-12p-tetrasomy-without-pallister-killian-syndrome
#8
Viola Alesi, Maria L Dentici, Fabrizia Restaldi, Valeria Orlando, Maria T Liambo, Chiara Calacci, Rossella Capolino, Maria C Digilio, May El Hachem, Antonio Novelli, Andrea Diociaiuti, Bruno Dallapiccola
Pallister-Killian syndrome (PKS-#OMIM601803) is a multisystem developmental disorder typically due to the presence of an aneuploidy cell line, consisting of a supernumerary tetrasomic chromosomal marker (SCM) arisen from the short arm of chromosome 12 (12p isochromosome). The clinical phenotype, which is strictly related to the percentage and tissue distribution of aneuploid cells, is characterized by craniofacial dysmorphisms, pigmentary skin anomalies, limb shortening, congenital heart defects, diaphragmatic hernia, hypotonia, intellectual disability, and epilepsy...
May 10, 2017: American Journal of Medical Genetics. Part A
https://www.readbyqxmd.com/read/28485098/production-of-a-fungal-furocoumarin-by-a-polyketide-synthase-gene-cluster-confers-the-chemo-resistance-of-neurospora-crassa-to-the-predation-by-fungivorous-arthropods
#9
Yanxia Zhao, Jianing Ding, Weihua Yuan, Jinjin Huang, Wenxiu Huang, Yan Wang, Weifa Zheng
The formation of sexual fruiting bodies and production of polyketides are believed to be the most important strategies for fungal survival in environmental insults. In Neurospora crassa, the backbone gene of polyketide synthase gene cluster 6 (pks-6), which is expressed at lower level under vegetative growth, is highly expressed during perithecia development. Intriguingly, deletion of pks-6 does not affect perithecia maturation. How the expression of pks-6 correlates with fungal sexual development remains to be established...
May 9, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28484706/endophytic-actinobacteria-associated-with-dracaena-cochinchinensis-lour-isolation-diversity-and-their-cytotoxic-activities
#10
Nimaichand Salam, Thi-Nhan Khieu, Min-Jiao Liu, Thu-Trang Vu, Son Chu-Ky, Ngoc-Tung Quach, Quyet-Tien Phi, Manik Prabhu Narsing Rao, Angélique Fontana, Samira Sarter, Wen-Jun Li
Dracaena cochinchinensis Lour. is an ethnomedicinally important plant used in traditional Chinese medicine known as dragon's blood. Excessive utilization of the plant for extraction of dragon's blood had resulted in the destruction of the important niche. During a study to provide a sustainable way of utilizing the resources, the endophytic Actinobacteria associated with the plant were explored for potential utilization of their medicinal properties. Three hundred and four endophytic Actinobacteria belonging to the genera Streptomyces, Nocardiopsis, Brevibacterium, Microbacterium, Tsukamurella, Arthrobacter, Brachybacterium, Nocardia, Rhodococcus, Kocuria, Nocardioides, and Pseudonocardia were isolated from different tissues of D...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28484029/polyketide-mimetics-yield-structural-and-mechanistic-insights-into-product-template-domain-function-in-nonreducing-polyketide-synthases
#11
Jesus F Barajas, Gaurav Shakya, Gabriel Moreno, Heriberto Rivera, David R Jackson, Caitlyn L Topper, Anna L Vagstad, James J La Clair, Craig A Townsend, Michael D Burkart, Shiou-Chuan Tsai
Product template (PT) domains from fungal nonreducing polyketide synthases (NR-PKSs) are responsible for controlling the aldol cyclizations of poly-β-ketone intermediates assembled during the catalytic cycle. Our ability to understand the high regioselective control that PT domains exert is hindered by the inaccessibility of intrinsically unstable poly-β-ketones for in vitro studies. We describe here the crystallographic application of "atom replacement" mimetics in which isoxazole rings linked by thioethers mimic the alternating sites of carbonyls in the poly-β-ketone intermediates...
May 8, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28475838/potent-nematicidal-activity-and-new-hybrid-metabolite-production-by-disruption-of-a-cytochrome-p450-gene-involved-in-the-biosynthesis-of-morphological-regulatory-arthrosporols-in-nematode-trapping-fungus-arthrobotrys-oligospora
#12
Tian-Yang Song, Zi-Fei Xu, Yong-Hong Chen, Qiu-Yan Ding, Yu-Rong Sun, Yang Miao, Ke-Qin Zhang, Xue-Mei Niu
Types of polyketide synthase-terpenoid synthase (PKS-TPS) hybrid metabolites, including arthrosporols with significant morphological regulatory activity, have been elucidated from nematode-trapping fungus Arthrobotrys oligospora. A previous study suggested that the gene cluster AOL_s00215 in A. oligospora was involved in the production of arthrosporols. Here, we report that disruption of one cytochrome P450 monooxygenase gene AOL_s00215g280 in the cluster resulted in significant phenotypic difference and much aerial hyphae...
May 15, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28471414/melanisation-of-aspergillus-terreus-is-butyrolactone-i-involved-in-the-regulation-of-both-dopa-and-dhn-types-of-pigments-in-submerged-culture
#13
Elina K Palonen, Sheetal Raina, Annika Brandt, Jussi Meriluoto, Tajalli Keshavarz, Juhani T Soini
Pigments and melanins of fungal spores have been investigated for decades, revealing important roles in the survival of the fungus in hostile environments. The key genes and the encoded enzymes for pigment and melanin biosynthesis have recently been found in Ascomycota, including Aspergillus spp. In Aspergillus terreus, the pigmentation has remained mysterious with only one class of melanin biogenesis being found. In this study, we examined an intriguing, partially annotated gene cluster of A. terreus strain NIH2624, utilizing previously sequenced transcriptome and improved gene expression data of strain MUCL 38669, under the influence of a suggested quorum sensing inducing metabolite, butyrolactone I...
May 4, 2017: Microorganisms
https://www.readbyqxmd.com/read/28467833/heterologous-production-and-yield-improvement-of-epothilones-in-burkholderiales-strain-dsm-7029
#14
Xiaoying Bian, Biao Tang, Yucong Yu, Qiang Tu, Frank Gross, Hailong Wang, Aiying Li, Jun Fu, Yuemao Shen, Yue-Zhong Li, A Francis Stewart, Guoping Zhao, Xiaoming Ding, Rolf Müller, Youming Zhang
The cloning of microbial natural product biosynthetic gene clusters and their heterologous expression in a suitable host have proven to be a feasible approach to improve the yield of valuable natural products and to begin mining cryptic natural products in microorganisms. Myxobacteria are a prolific source of novel bioactive natural products with only limited choices of heterologous hosts that have been exploited. Here, we describe the use of Burkholderiales strain DSM 7029 as a potential heterologous host for the functional expression of myxobacterial secondary metabolites...
May 18, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28464455/a-long-range-acting-dehydratase-domain-as-the-missing-link-for-c17-dehydration-in-iso-migrastatin-biosynthesis
#15
Ben Shen, Bo Zhang, Zhengren Xu, Qihui Teng, Guohui Pan, Ming Ma
The dehydratase domains (DHs) of the iso-migrastatin (iso-MGS) polyketide synthase (PKS) were investigated by systematic inactivation of the DHs in module-6, -9, -10 of MgsF (i.e., DH6, DH9, DH10) and module-11 of MgsG (i.e., DH11) in vivo, followed by structural characterization of the metabolites accumulated by the mutants, and biochemical characterization of DH10 in vitro, using polyketide substrate mimics with varying chain lengths. These studies allowed us to assign the functions for all four DHs, identifying DH10 as the dedicated dehydratase that catalyzes the dehydration of the C17 hydroxy group during iso-MGS biosynthesis...
May 2, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28463421/aromatic-polyketide-gtri-02-is-a-previously-unidentified-product-of-the-act-gene-cluster-in-streptomyces-coelicolor-a3-2
#16
Changsheng Wu, Koji Ichinose, Young Hae Choi, Gilles P van Wezel
The biosynthesis of aromatic polyketides derived from type II polyketide synthase (PKS) is complex, and it is not uncommon that highly similar gene clusters give rise to diverse structural architectures. The act biosynthetic gene cluster (BGC) of the model actinomycete Streptomyces coelicolor A3(2) is an archetypal type II PKS. Here, we show that the act BGC also specifies the aromatic polyketide GTRI-02 (1), and propose a mechanism for the biogenesis of its 3,4-dihydronaphthalen-1(2H)-one backbone. 1 was also produced by Streptomyces sp...
April 30, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28460913/molecular-and-mycotoxigenic-biodiversity-of-aspergillus-flavus-isolated-from-brazil-nuts
#17
Arianne Costa Baquião, Evandro Luiz Lopes, Benedito Corrêa
The objective of this study was to carry out a transcription analysis of eight genes belonging to the aflatoxin (AF) and cyclopiazonic acid (CPA) biosynthesis pathway, and to detect aflatoxin B1 (AFB1) and CPA production in Aspergillus flavus strains isolated from Brazil nuts. Additionally, these genes were correlated with the different mycotoxigenic profiles of the same strains. Four previously identified A. flavus strains (ICB-01, ICB-151, ICB-161, and ICB-165) were grown on Brazil nut agar at 25°C for 10days...
November 2016: Food Research International
https://www.readbyqxmd.com/read/28460065/sbspksv2-structure-based-sequence-analysis-of-polyketide-synthases-and-non-ribosomal-peptide-synthetases
#18
Shradha Khater, Money Gupta, Priyesh Agrawal, Neetu Sain, Jyoti Prava, Priya Gupta, Mansi Grover, Narendra Kumar, Debasisa Mohanty
Genome guided discovery of novel natural products has been a promising approach for identification of new bioactive compounds. SBSPKS web-server has been a valuable resource for analysis of polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) gene clusters. We have developed an updated version - SBSPKSv2 which is based on comprehensive analysis of sequence, structure and secondary metabolite chemical structure data from 311 experimentally characterized PKS/NRPS gene clusters with known biosynthetic products...
April 29, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28453782/sempi-a-genome-based-secondary-metabolite-prediction-and-identification-web-server
#19
Paul F Zierep, Natàlia Padilla, Dimitar G Yonchev, Kiran K Telukunta, Dennis Klementz, Stefan Günther
The secondary metabolism of bacteria, fungi and plants yields a vast number of bioactive substances. The constantly increasing amount of published genomic data provides the opportunity for an efficient identification of gene clusters by genome mining. Conversely, for many natural products with resolved structures, the encoding gene clusters have not been identified yet. Even though genome mining tools have become significantly more efficient in the identification of biosynthetic gene clusters, structural elucidation of the actual secondary metabolite is still challenging, especially due to as yet unpredictable post-modifications...
April 27, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28451290/activation-and-characterization-of-a-cryptic-gene-cluster-reveals-a-cyclization-cascade-for-polycyclic-tetramate-macrolactams
#20
Subhasish Saha, Wenjun Zhang, Guangtao Zhang, Yiguang Zhu, Yuchan Chen, Wei Liu, Chengshan Yuan, Qingbo Zhang, Haibo Zhang, Liping Zhang, Weimin Zhang, Changsheng Zhang
Polycyclic tetramate macrolactams (PTMs) are a growing class of natural products and are derived from a hybrid polyketide synthase (PKS)/non-ribosomal peptide synthetase (NRPS) pathway. PTM biosynthetic gene clusters are conserved and widely distributed in bacteria, however, most of them remain silent. Herein we report the activation of a PTM gene cluster in marine-derived Streptomyces pactum SCSIO 02999 by promoter engineering and heterologous expression, leading to the discovery of six new PTMs, pactamides A-F (11-16), with potent cytotoxic activity upon several human cancer cell lines...
February 1, 2017: Chemical Science
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