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https://www.readbyqxmd.com/read/28812299/conversion-of-the-high-yield-salinomycin-producer-streptomyces-albus-bk3-25-into-a-surrogate-host-for-polyketide-production
#1
Xiaojie Zhang, Chenyang Lu, Linquan Bai
An ideal surrogate host for heterologous production of various natural products is expected to have efficient nutrient utilization, fast growth, abundant precursors and energy supply, and a pronounced gene expression. Streptomyces albus BK3-25 is a high-yield industrial strain producing type-I polyketide salinomycin, with a unique ability of bean oil utilization. Its potential of being a surrogate host for heterologous production of PKS was engineered and evaluated herein. Firstly, introduction of a three-gene cassette for the biosynthesis of ethylmalonyl-CoA resulted in accumulation of ethylmalonyl-CoA precursor and salinomycin, and subsequent deletion of the salinomycin biosynthetic gene cluster resulted in a host with rich supplies of common polyketide precursors, including malonyl-CoA, methylmalonyl-CoA, and ethylmalonyl-CoA...
August 14, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28812297/neomycin-biosynthesis-is-regulated-positively-by-afsa-g-and-neor-in-streptomyces-fradiae-cgmcc-4-7387
#2
Xiangxi Meng, Wenzhao Wang, Zhoujie Xie, Pengwei Li, Yue Li, Zhengyan Guo, Yingjian Lu, Jie Yang, Kaile Guan, Zhaoxin Lu, Huarong Tan, Yihua Chen
Neomycins are a group of aminoglycoside antibiotics with both clinical and agricultural applications. To elucidate the regulatory mechanism of neomycin biosynthesis, we completed draft genome sequencing of a neomycin producer Streptomyces fradiae CGMCC 4.7387 from marine sediments, and the neomycin biosynthesis gene cluster was identified. Inactivation of the afsA-g gene encoding a γ-butyrolactone (GBL) synthase in S. fradiae CGMCC 4.7387 resulted in a significant decrease of neomycin production. Quantitative RT-PCR analysis revealed that the transcriptional level of neoR and the aphA-neoGH operon were reduced in the afsA-g::aac(3)IV mutant...
August 14, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28811620/a-new-anthracycline-type-metabolite-from-streptomyces-sp-neau-l3
#3
Chang Lu, Yue Zhao, Wei-Qi Jia, Hui Zhang, Huan Qi, Wen-Sheng Xiang, Ji-Dong Wang, Xiang-Jing Wang
A new anthracycline-type metabolite, designated as tetracenoquinocin A (1), was isolated from the fermentation broth of Streptomyces sp. NEAU-L3. Its structure was determined on the basis of spectroscopic analysis, including 1D and 2D NMR techniques as well as ESI-MS and comparison with data from the literature. Compound 1 showed potent cytotoxic activity against three cancer cell lines (HepG2, A549, HCT-116) with IC50 values of 5.57, 24.30 and 20.82 μM, respectively.The Journal of Antibiotics advance online publication, 16 August 2017; doi:10...
August 16, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/28811116/identification-of-nocardia-streptomyces-and-tsukamurella-using-maldi-tof-ms-with-the-bruker-biotyper
#4
Melanie L Yarbrough, William Lainhart, Carey-Ann D Burnham
Nocardia species are the most commonly isolated aerobic actinomycetes from human clinical specimens. Our objective was to assess the identification of clinically relevant actinomycetes using the Bruker Biotyper MALDI-TOF system, including comparison of extraction methods, Biotyper library versions, score cutoffs, and media. Banked Streptomyces (n=10), Tsukamurella (n=2), and Nocardia isolates (n=60) were cultured and extracted using three methods: mycobacterial extraction, ethanol formic acid extraction, or direct on-target extraction...
July 1, 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/28809552/characterization-of-2-oxindole-forming-heme-enzyme-mare-expanding-the-functional-diversity-of-the-tryptophan-dioxygenase-superfamily
#5
Yuyang Zhang, Yi Zou, Nelson L Brock, Tingting Huang, Yingxia Lan, Xiaozheng Wang, Zixin Deng, Yi Tang, Shuangjun Lin
3-Substituted 2-oxindoles are important structural motifs found in many biologically active natural products and pharmaceutical lead compounds. Here, we report an enzymatic formation of the 3-substituted 2-oxindoles catalyzed by MarE in the maremycin biosynthetic pathway in Streptomyces sp. B9173. MarE is a homologue of Fe(II)/heme-dependent tryptophan 2,3-dioxygenases (TDOs). Typical TDOs usually catalyze the insertion of two oxygen atoms from O2 into an indole ring to generate N-formylkynurenine (NFK)-like products...
August 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28808748/erratum-to-characterization-of-three-pathway-specific-regulators-for-high-production-of-monensin-in-streptomyces-cinnamonensis
#6
Zheng-Kun Tang, Xiao-Mei Li, Ai-Ping Pang, Chun-Yan Lin, Yue Zhang, Jie Zhang, Jianjun Qiao, Guang-Rong Zhao
No abstract text is available yet for this article.
August 14, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28804253/effect-of-microbial-activity-on-penetrometer-resistance-and-elastic-modulus-of-soil-at-different-temperatures
#7
W Gao, V Muñoz-Romero, T Ren, R W Ashton, M Morin, I M Clark, D S Powlson, W R Whalley
We explore the effect of microbial activity stimulated by root exudates on the penetrometer resistance of soil and its elastic modulus. This is important because it is a measure of the mechanical strength of soil and it correlates closely with the rate of elongation of roots. A sandy soil was incubated with a synthetic root exudate at different temperatures, for different lengths of time and with selective suppression of either fungi or bacteria. The shape of the temperature response of penetrometer resistance in soil incubated with synthetic exudate was typical of a poikilothermic temperature response...
July 2017: European Journal of Soil Science
https://www.readbyqxmd.com/read/28800088/upregulation-and-identification-of-antibiotic-activity-of-a-marine-derived-streptomyces-sp-via-co-cultures-with-human-pathogens
#8
Anne A Sung, Samantha M Gromek, Marcy J Balunas
Marine natural product drug discovery has begun to play an important role in the treatment of disease, with several recently approved drugs. In addition, numerous microbial natural products have been discovered from members of the order Actinomycetales, particularly in the genus Streptomyces, due to their metabolic diversity for production of biologically active secondary metabolites. However, many secondary metabolites cannot be produced under laboratory conditions because growth conditions in flask culture differ from conditions in the natural environment...
August 11, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28796837/whole-genome-sequence-of-two-rathayibacter-toxicus-strains-reveals-a-tunicamycin-biosynthetic-cluster-similar-to-streptomyces-chartreusis
#9
Aaron J Sechler, Matthew A Tancos, David J Schneider, Jonas G King, Christine M Fennessey, Brenda K Schroeder, Timothy D Murray, Douglas G Luster, William L Schneider, Elizabeth E Rogers
Rathayibacter toxicus is a forage grass associated Gram-positive bacterium of major concern to food safety and agriculture. This species is listed by USDA-APHIS as a plant pathogen select agent because it produces a tunicamycin-like toxin that is lethal to livestock and may be vectored by nematode species native to the U.S. The complete genomes of two strains of R. toxicus, including the type strain FH-79, were sequenced and analyzed in comparison with all available, complete R. toxicus genomes. Genome sizes ranged from 2,343,780 to 2,394,755 nucleotides, with 2079 to 2137 predicted open reading frames; all four strains showed remarkable synteny over nearly the entire genome, with only a small transposed region...
2017: PloS One
https://www.readbyqxmd.com/read/28792368/streptomyces-phaeopurpureus-shinobu-1957-approved-lists-1980-and-streptomyces-griseorubiginosus-ryabova-and-preobrazhenskaya-1957-pridham-et-al-1958-approved-lists-1980-are-heterotypic-subjective-synonyms
#10
Peter Kämpfer, Christian Rückert, Jochen Blom, Alexander Goesmann, Joachim Wink, Jörn Kalinowski, Stefanie P Glaeser
On the basis of whole genome comparisons of Streptomyces griseorubiginosus and Streptomyces phaeopurpureus it could by shown that these two species are subjective synonyms. The names of both species have been published in the Approved Lists of Bacterial Names and, in such a case, normally Rule 24b (1) of the Prokaryotic Code applies, which reads: 'If two names compete for priority and if both names date from 1 January 1980 on an Approved List, the priority shall be determined by the date of the original publication of the name before 1 January 1980'...
August 10, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28783117/the-role-of-functional-amyloids-in-multicellular-growth-and-development-of-gram-positive-bacteria
#11
REVIEW
Anna Dragoš, Ákos T Kovács, Dennis Claessen
Amyloid fibrils play pivotal roles in all domains of life. In bacteria, these fibrillar structures are often part of an extracellular matrix that surrounds the producing organism and thereby provides protection to harsh environmental conditions. Here, we discuss the role of amyloid fibrils in the two distant Gram-positive bacteria, Streptomyces coelicolor and Bacillus subtilis. We describe how amyloid fibrils contribute to a multitude of developmental processes in each of these systems, including multicellular growth and community development...
August 7, 2017: Biomolecules
https://www.readbyqxmd.com/read/28782575/toxicological-evaluation-of-neoagarooligosaccharides-prepared-by-enzymatic-hydrolysis-of-agar
#12
Sun Joo Hong, Je-Hyeon Lee, Eun Joo Kim, Hea Jung Yang, Jae-Seon Park, Soon-Kwang Hong
Agar, a heterogeneous polymer of galactose, is the main component of the cell wall of marine red algae. It is well established as a safe, non-digestible carbohydrate in Oriental countries. Although neoagarooligosaccharides (NAOs) prepared by the hydrolysis of agar by β-agarase have been reported to exert various biological activities, the safety of these compounds has not been reported to date. For safety evaluation, NAOs containing mainly neoagarotetraose and neoagarohexaose were prepared from agar by enzymatic hydrolysis using β-agarase DagA from Streptomyces coelicolor...
August 3, 2017: Regulatory Toxicology and Pharmacology: RTP
https://www.readbyqxmd.com/read/28777959/fast-growing-algicidal-streptomyces-sp-u3-and-its-potential-in-harmful-algal-bloom-controls
#13
Xiaoqi Yu, Guanjing Cai, Hui Wang, Zhong Hu, Wei Zheng, Xueqian Lei, Xiaoying Zhu, Yao Chen, Qiuliang Chen, Hongyan Din, Hong Xu, Yun Tian, Lijun Fu, Tianling Zheng
To find the potential algicidal microorganisms and apply them to prevent and terminate harmful algal blooms (HABs), we isolated an actinomycete U3 from Mangrove, which had a potent algicidal effect on the harmful alga Heterosigma akashiwo. It could completely lyse the algal cells by producing active compounds, which were highly sensitive to high temperature and strong alkaline, but resistant to acid. One μg/mL of crude extract of the fermentation supernatant could kill 70% of H. akashiwo cells in 3 d. Unlike most of the other known algicidal Streptomyces, U3 showed strong ability of proliferation with the algal inclusion as the nutrient source...
June 23, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28776993/improving-the-catalytic-behavior-of-dfa-i-forming-inulin-fructotransferase-from-streptomyces-davawensis-with-site-directed-mutagenesis
#14
Shuhuai Yu, Yanmin Zhang, Yingying Zhu, Tao Zhang, Bo Jiang, Wanmeng Mu
Previously, a α-D-fructofuranose-β-D-fructofuranose 1,2':2,1'-dianhydride (DFA I)-forming inulin fructotransferase (IFTase), namely SdIFTase, was identified. The enzyme doesn't show high performances. In this work, to improve catalytic behavior including activity and thermostability, the enzyme was modified using site-directed mutagenesis on the basis of structure. The mutated residues were divided into three groups. Those in group I are located at central tunnel including G236, A257, G281, T313, and A314S...
August 4, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28776273/combining-metabolomics-and-network-analysis-to-improve-tacrolimus-production-in-streptomyces-tsukubaensis-using-different-exogenous-feedings
#15
Cheng Wang, Jiao Liu, Huanhuan Liu, Shaoxiong Liang, Jianping Wen
Tacrolimus is widely used as an immunosuppressant in the treatment of various autoimmune diseases. However, the low fermentation yield of tacrolimus has thus far restricted its industrial applications. To solve this problem, the time-series response mechanisms of the intracellular metabolism that were highly correlated with tacrolimus biosynthesis were investigated using different exogenous feeding strategies in S. tsukubaensis. The metabolomic datasets, which contained 93 metabolites, were subjected to weighted correlation network analysis (WGCNA), and eight distinct metabolic modules and seven hub metabolites were identified to be specifically associated with tacrolimus biosynthesis...
August 3, 2017: Journal of Industrial Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28774961/identification-and-characterization-of-a-bacterial-cytochrome-p450-monooxygenase-catalyzing-the-3-nitration-of-tyrosine-in-rufomycin-biosynthesis
#16
Hiroya Tomita, Yohei Katsuyama, Hiromichi Minami, Yasuo Ohnishi
Rufomycin is a circular heptapeptide with anti-mycobacterial activity and is produced by Streptomyces atratus ATCC 14046. Its structure contains three non-proteinogenic amino acids, N-dimethylallyltryptophan, trans-2-crotylglycine, and 3-nitrotyrosine (3NTyr). Although the rufomycin structure was already reported in the 1960s, its biosynthesis, including 3-NTyr generation, remains unclear. To elucidate the rufomycin biosynthetic pathway, we assembled a draft genome sequence of S. atratus and identified the rufomycin biosynthetic gene cluster (ruf cluster), consisting of 20 ORFs (rufA-rufT)...
August 3, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28774308/polarity-directed-optimization-of-phytochemical-and-in-vitro-biological-potential-of-an-indigenous-folklore-quercus-dilatata-lindl-ex-royle
#17
Madiha Ahmed, Humaira Fatima, Muhammad Qasim, Bilquees Gul, Ihsan-Ul-Haq
BACKGROUND: Plants have served either as a natural templates for the development of new chemicals or a phytomedicine since antiquity. Therefore, the present study was aimed to appraise the polarity directed antioxidant, cytotoxic, protein kinase inhibitory, antileishmanial and glucose modulatory attributes of a Himalayan medicinal plant- Quercus dilatata. METHODS: Total phenolic and flavonoid contents were determined colorimetrically and various polyphenols were identified by RP-HPLC analysis...
August 3, 2017: BMC Complementary and Alternative Medicine
https://www.readbyqxmd.com/read/28770367/carbon-catabolite-regulation-in-streptomyces-new-insights-and-lessons-learned
#18
REVIEW
Alba Romero-Rodríguez, Diana Rocha, Beatriz Ruiz-Villafán, Silvia Guzmán-Trampe, Nidia Maldonado-Carmona, Melissa Vázquez-Hernández, Augusto Zelarayán, Romina Rodríguez-Sanoja, Sergio Sánchez
One of the most significant control mechanisms of the physiological processes in the genus Streptomyces is carbon catabolite repression (CCR). This mechanism controls the expression of genes involved in the uptake and utilization of alternative carbon sources in Streptomyces and is mostly independent of the phosphoenolpyruvate phosphotransferase system (PTS). CCR also affects morphological differentiation and the synthesis of secondary metabolites, although not all secondary metabolite genes are equally sensitive to the control by the carbon source...
September 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28767052/strepchazolins-a-and-b-two-new-alkaloids-from-a-marine-streptomyces-chartreusis-na02069
#19
Cheng-Long Yang, Yi-Shuang Wang, Cheng-Li Liu, Ying-Jie Zeng, Ping Cheng, Rui-Hua Jiao, Shi-Xiang Bao, Hui-Qin Huang, Ren-Xiang Tan, Hui-Ming Ge
Two new alkaloids, strepchazolins A (1) and B (2), together with a previously reported compound, streptazolin (3), were isolated from a marine actinomycete, Streptomyces chartreusis NA02069, collected in the Coast of Hainan Island, China. The structures of new compounds were determined by extensive NMR, mass spectroscopic and X-ray crystallographic analysis, as well as modified Mosher's method. Compound 1 showed weak anti-Bacillus subtilis activity with the MIC value of 64.0 μM, and weak inhibitory activity against acetylcholinesterase (AChE) in vitro with IC50 value of 50...
August 2, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28765588/rakicidin-f-a-new-antibacterial-cyclic-depsipeptide-from-a-marine-sponge-derived-streptomyces-sp
#20
Shigeru Kitani, Tatsuya Ueguchi, Yasuhiro Igarashi, Kantinan Leetanasaksakul, Arinthip Thamchaipenet, Takuya Nihira
A new cyclic depsipeptide, rakicidin F (1), along with the known compound rakicidin C (2), was isolated from the fermentation broth of the marine sponge-derived actinomycete strain Streptomyces sp. GKU 220. Their structures were elucidated by interpreting the HRFABMS and NMR spectroscopic data. Rakicidin F (1) showed growth inhibitory activity against bacteria.The Journal of Antibiotics advance online publication, 2 August 2017; doi:10.1038/ja.2017.92.
August 2, 2017: Journal of Antibiotics
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