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Journal of Antibiotics

Juan F Martín, Antonio Rodríguez-García, Paloma Liras
Phosphate limitation is important for production of antibiotics and other secondary metabolites in Streptomyces. Phosphate control is mediated by the two-component system PhoR-PhoP. Following phosphate depletion, PhoP stimulates expression of genes involved in scavenging, transport and mobilization of phosphate, and represses the utilization of nitrogen sources. PhoP reduces expression of genes for aerobic respiration and activates nitrate respiration genes. PhoP activates genes for teichuronic acid formation and reduces expression of genes for phosphate-rich teichoic acid biosynthesis...
March 15, 2017: Journal of Antibiotics
Atsushi Fukumoto, Yong-Pil Kim, Atsuko Matsumoto, Yoko Takahashi, Makoto Suzuki, Hideyuki Onodera, Hiroshi Tomoda, Hidehito Matsui, Hideaki Hanaki, Masato Iwatsuki, Satoshi Ōmura, Kazuro Shiomi
Screening for circumventors of β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) led us to find 17 novel antibiotics, naphthacemycins A1-A11, B1-B4 and C1-C2. The naphthacemycins were isolated from a cultured broth of Streptomyces sp. KB-3346-5 by repeated silica gel column chromatography and HPLC. Naphthacemycins enhanced imipenem activity 100-500 times against MRSA at 0.5 μg ml(-1), and naphthacemycins A4-A11 themselves showed MIC50 values of 1-4 μg ml(-1) against 22 MRSA strains...
March 15, 2017: Journal of Antibiotics
Hideki Hashizume, Ryuichi Sawa, Kazuma Yamashita, Yoshio Nishimura, Masayuki Igarashi
No abstract text is available yet for this article.
March 15, 2017: Journal of Antibiotics
Atsushi Fukumoto, Yong-Pil Kim, Masato Iwatsuki, Tomoyasu Hirose, Toshiaki Sunazuka, Hideaki Hanaki, Satoshi Ōmura, Kazuro Shiomi
Seventeen new compounds, naphthacemycins A1-A11, B1-B4 and C1-C2, were isolated from a cultured broth of Streptomyces sp. KB-3346-5 during screening for circumventors of β-lactam resistance in methicillin-resistant Staphylococcus aureus. Their structures were elucidated by spectroscopic studies, including NMR and X-ray crystallographic analysis. The naphthacemycin A series has a new skeleton displaying a 7-phenylnaphthacene-5,6,11(12H)-trione. In contrast, the quinone moiety of the A series is changed to dehydroxyquinol in the B series and to a semiquinone-like structure in the C series...
March 15, 2017: Journal of Antibiotics
Jia-Hui Xu, Kang-Bo Gu, Dao-Jing Zhang, Yuan-Guang Li, Li Tian
Two novel γ-butyrolactones ghanamycins A (1) and B (2) were isolated from the fermentation broth of marine-derived Streptomyces ghanaensis TXC6-16. Their structures were elucidated by spectroscopic analysis. These two novel compounds exhibited antimicrobial activities against some phytopathogens. The minimum IC (MIC) of 2 against Pseudomonas syringae and Erwinia sp. were 50 μg ml(-1).The Journal of Antibiotics advance online publication, 15 March 2017; doi:10.1038/ja.2017.37.
March 15, 2017: Journal of Antibiotics
Ayako Nara, Takuya Hashimoto, Mamoru Komatsu, Makoto Nishiyama, Tomohisa Kuzuyama, Haruo Ikeda
Bafilomycins A1, C1 and B1 (setamycin) produced by Kitasatospora setae KM-6054 belong to the plecomacrolide family, which exhibit antibacterial, antifungal, antineoplastic and immunosuppressive activities. An analysis of gene clusters from K. setae KM-6054 governing the biosynthesis of bafilomycins revealed that it contains five large open reading frames (ORFs) encoding the multifunctional polypeptides of bafilomycin polyketide synthases (PKSs). These clustered PKS genes, which are responsible for bafilomycin biosynthesis, together encode 11 homologous sets of enzyme activities, each catalyzing a specific round of polyketide chain elongation...
March 15, 2017: Journal of Antibiotics
Naftale Katz, Neusa Araújo, Paulo Marcos Zech Coelho, Carlos Medicis Morel, Ana Rosa Linde-Arias, Takeshi Yamada, Yuki Horimatsu, Koh Suzuki, Toshiaki Sunazuka, Satoshi Ōmura
The impact of ivermectin on adult snails of the genus Biomphalaria (B. glabrata, B. tenagophila and B. straminea), B. glabrata infected with Schistosoma mansoni, snail egg-masses cercariae and miracidia, as well as on guppy fish (Poecilia reticulata) was examined and evaluated. Biomphalaria snails, egg-masses, parasite stages and guppies were all exposed to different concentrations of ivermectin for 24 h, followed by regular observations of mortality. The calculated lethal doses of ivermectin were around an LD50 of 0...
March 15, 2017: Journal of Antibiotics
Atsuko Matsumoto, Yōko Takahashi
Endophytic actinomycetes associated with plant roots are a relatively untapped source of potential new bioactive compounds. This is becoming increasingly important, as the returns from discovery research on soil-dwelling microbes, have been continuously diminishing. We have isolated more than 1000 strains of actinomycetes from plant roots in our search for novel bioactive compounds, identified and assayed their bioactive metabolites, as well as investigated their biosynthetic genes for generating secondary metabolites...
March 8, 2017: Journal of Antibiotics
Catalina F Pérez Hemphill, Parichat Sureechatchaiyan, Matthias U Kassack, Raha S Orfali, Wenhan Lin, Georgios Daletos, Peter Proksch
Using the OSMAC (One Strain MAny Compounds) approach, the fungal endophyte Fusarium tricinctum was cultivated on fruit and vegetable juice-supplemented solid rice media. This led to an up to 80-fold increase in the accumulation of the new natural product fusarielin J (1), as well as to the induction of two new natural products fusarielin K (2) and fusarielin L (3) and the known derivatives fusarielins A (4) and B (5). Compounds 2-5 were not detected when the fungus was grown on rice media lacking either fruit or vegetable juice...
March 8, 2017: Journal of Antibiotics
Naoya Oku, Sayaka Hana, Miyako Matsumoto, Kohsuke Yonejima, Keijiroh Tansei, Yasuhiro Isogai, Yasuhiro Igarashi
No abstract text is available yet for this article.
March 8, 2017: Journal of Antibiotics
Sandip S Shinde, Atsushi Minami, Zhi Chen, Tetsuo Tokiwano, Tomonobu Toyomasu, Nobuo Kato, Takeshi Sassa, Hideaki Oikawa
Elucidation of the cyclization mechanism catalyzed by terpene synthases is important for the rational engineering of terpene cyclases. We developed a chemoenzymatic method for the synthesis of systematically deuterium-labeled geranylgeranyl diphosphate (GGPP), starting from site-specifically deuterium-labeled isopentenyl diphosphates (IPPs) using IPP isomerase and three prenyltransferases. We examined the cyclization mechanism of tetracyclic diterpene phomopsene with phomopsene synthase. A detailed EI-MS analysis of phomopsene labeled at various positions allowed us to propose the structures corresponding to the most intense peaks, and thus elucidate a cyclization mechanism involving double 1,2-alkyl shifts and a 1,2-hydride shift via a dolabelladien-15-yl cation...
March 8, 2017: Journal of Antibiotics
Meng-Hua Wang, Tao Jiang, Gang Ding, Shu-Bin Niu, Xue-Wei Wang, Meng Yu, Yu-Cheng Gu, Qiu-Bo Zhang, Jia-Huan Chen, Hong-Mei Jia, Zhong-Mei Zou
No abstract text is available yet for this article.
March 1, 2017: Journal of Antibiotics
Wayne Kw Chou, Colin A Gould, David E Cane
Incubation of synthetic 2-methylneryl diphosphate (2-MeNPP, 10) with 2-methylisoborneol synthase (MIBS) gave a mixture of products that differed significantly from that derived from the natural substrate (E)-2-methylgeranyl diphosphate (3, 2-MeGPP). The proportion of (-)-2-methylisoborneol (1) decreased from 89 to 17% while that of 2-methylenebornane (4) increased from 10 to 26%, with the relative yields of the isomeric homo-monoterpenes 2-methyl-2-bornene (5) and 1-methylcamphene (6) remaining essentially unchanged (<1% each), as determined by chiral GC-MS analysis...
March 1, 2017: Journal of Antibiotics
Kevin M N Burgess, Ashraf Ibrahim, Dan Sørensen, Mark W Sumarah
A strain of Hypoxylon submonticulosum was isolated as an endophyte from a surface-sterilized leaf of a cultivated raspberry (Rubus idaeus). The liquid culture extract displayed growth inhibition activity against Saccharomyces cerevisiae using a disc diffusion assay. The extract's major component was identified as a new natural product, trienylfuranol A (1S,2S,4R)-1-((1'E,3'E)-hexa-1',3',5'-trienyl)-tetrahydro-4-methylfuran-2-ol (1), by high-resolution LC-MS and 1D and 2D NMR spectroscopy. Two additional new metabolites, trienylfuranones A (2) and B (3), were isolated as minor components of the extract and their structure elucidation revealed that they were biosynthetically related to 1...
March 1, 2017: Journal of Antibiotics
Yasushi Ogasawara, Kensuke Kondo, Ayumi Ikeda, Rikako Harada, Tohru Dairi
No abstract text is available yet for this article.
March 1, 2017: Journal of Antibiotics
Evan Martens, Arnold L Demain
Beginning with the discovery of penicillin by Alexander Fleming in the late 1920s, antibiotics have revolutionized the field of medicine. They have saved millions of lives each year, alleviated pain and suffering, and have even been used prophylactically for the prevention of infectious diseases. However, we have now reached a crisis where many antibiotics are no longer effective against even the simplest infections. Such infections often result in an increased number of hospitalizations, more treatment failures and the persistence of drug-resistant pathogens...
March 1, 2017: Journal of Antibiotics
Yasuhiro Takehana, Maya Umekita, Masaki Hatano, Chiaki Kato, Ryuichi Sawa, Masayuki Igarashi
New bioactive substances were identified from several marine actinomycetes strains by LC-HRESI-MS based non-targeted metabolomics. A new siderophore and its derivative, named fradiamines A and B, were isolated from the extract of the deep-sea actinomycetes Streptomyces fradiae MM456M-mF7 by Diaion CHP-20P, Sephadex LH-20 column chromatography and HPLC. Fradiamine A was a new compound, but fradiamine B was previously patented as a sweetness enhancer. Their structures were determined by NMR and LC-HRESI-MS/MS analysis...
March 1, 2017: Journal of Antibiotics
Xiangcheng Zhu, Yanwen Duan, Zhaomeng Cui, Zhen Wang, Zengxia Li, Yun Zhang, Jianhua Ju, Hongbo Huang
Two new rearranged linear angucycline glycosides, designated grincamycins G and H (1 and 2), together with three known congers P-1894B (vineomycin A1, 3), saquayamycin B (4) and vineomycin B2 (5), were obtained from marine-derived actinomycete Streptomyces lusitanus SCSIO LR32. The structures of 1 and 2 were elucidated by MS, 1D and 2D NMR techniques. Compounds 2-5 showed significant inhibitory effect on Jurkat T-cell proliferation with IC50 values of 3.0, 0.011, 0.037 and 0.3 μM, respectively.The Journal of Antibiotics advance online publication, 22 February 2017; doi:10...
February 22, 2017: Journal of Antibiotics
Masaki Ohtawa, Shiho Arima, Risa Shimizu, Naomi Hanatani, Eri Shimizu, Kazuro Shiomi, Kiyoshi Kita, Satoshi Ōmura, Tohru Nagamitsu
Nafuredin-γ, obtained from natural nafuredin, has demonstrated a potent and selective inhibitory activity against nematode complex I. However, nafuredin-γ is unstable in air since its conjugated dienes are oxygen-labile. The instability in air was naturally solved by the synthesis of structure-simplified nafuredin-γ analogs without conjugated dienes. However, these modified analogs showed lower complex I inhibitory activities. Therefore, new air-stable structure-simplified nafuredin-γ analogs were designed and synthesized herein...
February 22, 2017: Journal of Antibiotics
Dong Yang, Mostafa E Rateb, Nan Wang, Ben Shen
No abstract text is available yet for this article.
February 15, 2017: Journal of Antibiotics
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