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Journal of Antibiotics

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https://www.readbyqxmd.com/read/29138482/valgamicin-c-a-novel-cyclic-depsipeptide-containing-the-unusual-amino-acid-cleonine-and-related-valgamicins-a-t-and-v-produced-by-amycolatopsis-sp-ml1-hf4
#1
Hideki Hashizume, Kiyoko Iijima, Kazuma Yamashita, Tomoyuki Kimura, Shun-Ichi Wada, Ryuichi Sawa, Masayuki Igarashi
In the course of optimizing pargamicin A production in Amycolatopsis sp. ML1-hF4, we discovered novel cyclic depsipeptide compounds in the broth and designated them valgamicins A, C, T and V. The structures of these molecules were determined by spectroscopic studies, advanced Marfey's method and X-ray crystal structural analysis. Valgamicin C contains the extremely rare amino acid cleonine. To our knowledge, this is the first report of a cleonine-containing metabolite from a naturally isolated microorganism without any breeding or mutation treatment...
November 15, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29138481/quadoctomycin-a-48-membered-macrolide-antibiotic-from-streptomyces-sp-mm168-141f8
#2
Ryuichi Sawa, Yumiko Kubota, Maya Umekita, Masaki Hatano, Chigusa Hayashi, Masayuki Igarashi
Drug-resistant bacteria are still emerging, and screening of new skeletal antibiotics is important. During our continuous screening for antimicrobial agents, we discovered a new antimicrobial, named quadoctomycin, from solid culture of Streptomyces sp. MM168-141F8. The substance was purified by solvent extraction, silica gel chromatography and HPLC. Structural elucidation of quadoctomycin was performed by MS and NMR analyses and chemical degradation. Quadoctomycin possesses a 48-membered polyol macrolide skeleton in which an α-D-mannoside is connected to C-22 by an O-glycosidic linkage...
November 15, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29115289/synthesis-and-antibacterial-activity-of-novel-lincomycin-derivatives-iv-optimization-of-an-n-6-substituent
#3
Ko Kumura, Yoshinari Wakiyama, Kazutaka Ueda, Eijiro Umemura, Yoko Hirai, Keiko Yamada, Keiichi Ajito
The design and synthesis of lincomycin derivatives modified at the C-6 and C-7 positions are described. A substituent at the C-7 position is a 5-aryl-1,3,4-thiadiazol-2-yl-thio group that generates antibacterial activities against macrolide-resistant Streptococcus pneumoniae and Streptococcus pyogenes carrying an erm gene. An additional modification at the C-6 position was explored in application of information regarding pirlimycin and other related compounds. These dual modifications were accomplished by using methyl α-thiolincosaminide as a starting material...
November 8, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089602/synthesis-of-deoxyelephantopin-analogues
#4
Roman Lagoutte, Christelle Serba, Nicolas Winssinger
Deoxyelephantopin is a sesquiterpene lactone that was reported to be as effective in the treatment of mammary tumours and lung metastasis as taxol based on a murine orthotopic cancer model. Its germacrene skeleton harbours three Michael acceptors that can potentially engage a target covalently. Its strained 10-membered ring is densely functionalised and represents an important synthetic challenge. We herein describe our studies towards deoxyelephantopins using a ring-closing metathesis approach and report some unexpected observations...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089601/selective-catalytic-hydrogenation-of-the-n-acyl-and-uridyl-double-bonds-in-the-tunicamycin-family-of-protein-n-glycosylation-inhibitors
#5
Neil Pj Price, Michael A Jackson, Karl E Vermillion, Judith A Blackburn, Jiakun Li, Biao Yu
Tunicamycin is a Streptomyces-derived inhibitor of eukaryotic protein N-glycosylation and bacterial cell wall biosynthesis, and is a potent and general toxin by these biological mechanisms. The antibacterial activity is dependent in part upon a π-π stacking interaction between the tunicamycin uridyl group and a specific Phe residue within MraY, a tunicamycin-binding protein in bacteria. We have previously shown that reducing the tunicamycin uridyl group to 5,6-dihydrouridyl (DHU) significantly lowers its eukaryotic toxicity, potentially by disrupting the π-stacking with the active site Phe...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089600/incentivising-innovation-in-antibiotic-drug-discovery-and-development-progress-challenges-and-next-steps
#6
REVIEW
Victoria L Simpkin, Matthew J Renwick, Ruth Kelly, Elias Mossialos
Political momentum and funding for combatting antimicrobial resistance (AMR) continues to build. Numerous major international and national initiatives aimed at financially incentivising the research and development (R&D) of antibiotics have been implemented. However, it remains unclear how to effectively strengthen the current set of incentive programmes to further accelerate antibiotic innovation. Based on a literature review and expert input, this study first identifies and assesses the major international, European Union, US and UK antibiotic R&D funding programmes...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089599/microbial-metabolites-and-derivatives-targeted-at-inflammation-and-bone-diseases-therapy-chemistry-biological-activity-and-pharmacology
#7
REVIEW
Hayamitsu Adachi, Koichi Nakae, Shuichi Sakamoto, Chisato Nosaka, Sonoko Atsumi, Masabumi Shibuya, Nobuaki Higashi, Motowo Nakajima, Tatsuro Irimura, Yoshio Nishimura
Microbial metabolites have attracted increasing interest as a source of therapeutics and as probes for biological mechanisms. New microbial metabolites and derivatives targeted at inflammation and bone disease therapy have been identified by focusing on prostaglandin release, osteoblast differentiation and immune cell functions. These modulators of inflammatory processes and bone disease contribute to our understanding of biological mechanisms and support identification of the therapeutic potential of drug lead candidates...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089598/cellular-uptake-of-modified-aminoglycosides
#8
Kaivin Hadidi, Ezequiel Wexselblatt, Jeffrey D Esko, Yitzhak Tor
The uptake of modified amino- and guanidino-glycosides derived from kanamycin, tobramycin and neomycin in native and mutant CHO cells is examined using confocal microscopy and flow cytometry, illustrating the significance of multivalency for mammalian cell internalization of carriers that specifically interact with cell surface heparan sulfate proteoglycans.The Journal of Antibiotics advance online publication, 1 November 2017; doi:10.1038/ja.2017.131.
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089597/our-microbes-not-only-produce-antibiotics-they-also-overproduce-amino-acids
#9
REVIEW
Sergio Sanchez, Romina Rodríguez-Sanoja, Allison Ramos, Arnold L Demain
Fermentative production of amino acids is an important goal of modern biotechnology. Through fermentation, micro-organisms growing on inexpensive carbon and nitrogen sources can produce a wide array of valuable products including amino acids. The amino acid market is $8 billion and mainly impacts the food, pharmaceutical and cosmetics industries. In terms of tons of amino acids produced per year by fermentation, L-glutamate is the most important amino acid produced (3.3 million), followed by L-lysine (2.2 million)...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089596/professor-hamao-umezawa-opened-up-a-new-road-for-the-development-of-molecularly-targeted-therapeutic-drugs-for-cancers
#10
REVIEW
Masaya Imoto
This issue is dedicated to Prof Hamao Umezawa in appreciation of his great contributions to pioneering research on antibiotics targeting oncogenes.The Journal of Antibiotics advance online publication, 1 November 2017; doi:10.1038/ja.2017.139.
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089595/self-control-of-the-pho-regulon-the-phop-dependent-protein-phou-controls-negatively-expression-of-genes-of-pho-regulon-in-streptomyces-coelicolor
#11
Seomara Martín-Martín, Antonio Rodríguez-García, Fernando Santos-Beneit, Etelvina Franco-Domínguez, Alberto Sola-Landa, Juan Francisco Martín
Phosphate control of the biosynthesis of secondary metabolites in Streptomyces is mediated by the two component system PhoR-PhoP. Linked to the phoR-phoP cluster, and expressed in the opposite orientation, is a phoU-like encoding gene with low identity to the phoU gene of Escherichia coli. Expression of this phoU-like gene is strictly dependent on PhoP activation. We have isolated a PhoU-null mutant and used transcriptomic and RNA-sequencing (RNA-seq) procedures to identify its transcription start site and regulation...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089594/synthesis-and-sars-of-novel-lincomycin-derivatives-part-5-optimization-of-lincomycin-analogs-exhibiting-potent-antibacterial-activities-by-chemical-modification-at-the-6-and-7-positions
#12
Yoshinari Wakiyama, Ko Kumura, Eijiro Umemura, Satomi Masaki, Kazutaka Ueda, Yasuo Sato, Yoko Hirai, Yoshio Hayashi, Keiichi Ajito
In order to modify lincomycin at the C-6 and C-7 positions, we prepared target molecules, which have substituted pipecolinic acid at the 6-amino group and a para-substituted phenylthio group at the C-7 position, in application of palladium-catalyzed cross-coupling as a key reaction. As the result of structure-activity relationship (SAR) studies at the 6-position, analogs possessing 4'-cis-(cyclopropylmethyl)piperidine showed significantly strong antibacterial activities against Streptococcus pneumoniae and Streptococcus pyogenes with an erm gene...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29089593/new-antituberculous-drugs-derived-from-natural-products-current-perspectives-and-issues-in-antituberculous-drug-development
#13
REVIEW
Masayuki Igarashi, Yoshimasa Ishizaki, Yoshiaki Takahashi
Tuberculosis is one of the most common and challenging infectious diseases worldwide. Especially, the lack of effective chemotherapeutic drugs for tuberculosis/human immunodeficiency virus co-infection and prevalence of multidrug-resistant and extensively drug-resistant tuberculosis remain to be serious clinical problems. Development of new drugs is a potential solution to fight tuberculosis. In this decade, the development status of new antituberculous drugs has been greatly advanced by the leading role of international organizations such as the Global Alliance for Tuberculosis Drug Development, Stop Tuberculosis Partnership and Global Health Innovative Technology Fund...
November 1, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066797/destination-of-aminoglycoside-antibiotics-in-the-post-antibiotic-era
#14
REVIEW
Yoshiaki Takahashi, Masayuki Igarashi
Aminoglycoside antibiotics (AGAs) were developed at the dawn of the antibiotics era and have significantly aided in the treatment of infectious diseases. Aminoglycosides have become one of the four major types of antibiotics in use today and, fortunately, still have an important role in the clinical treatment of severe bacterial infections. In this review, the current usage, modes of action and side effects of AGAs, along with the most common bacterial resistance mechanisms, are outlined. Finally, the recent development situation and possibility of new AGAs in the 'post-antibiotic era' are considered...
October 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066796/new-eremophilane-and-dichlororesorcinol-derivatives-produced-by-endophytes-isolated-from-ficus-ampelas
#15
Yoshihito Shiono, Niken Istikhari Muslihah, Takuma Suzuki, Nanang Rudianto Ariefta, Chairil Anwar, Handojo Hadi Nurjanto, Takako Aboshi, Tetsuya Murayama, Keitaro Tawaraya, Takuya Koseki, Jun Yoshida, Narandulam Usukhbayar, Shota Uesugi, Ken-Ichi Kimura
The novel compound, 11-O-methylpetasitol (1), was isolated from Penicillium sp. N-175-1, and two new compounds, cosmochlorins D (5) and E (6), were isolated from Phomopsis sp. N-125. In addition, three known eremophilane sesquiterpenes, sporogen-AO1 (2), petasol (3) and 6-dehydropetasol (4), were isolated from Penicillium sp. N-175-1. The structures of 1, 5 and 6 were elucidated by a combination of extensive spectroscopic analyses, including 2D NMR, high-resolution electrospray ionization time-of-flight mass spectrometry (HRESITOFMS) and chemical reactions...
October 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066795/a-new-eremophilane-sesquiterpene-from-the-fungus-xylaria-sp-v-27-and-inhibition-activity-against-degranulation-in-rbl-2h3-cells
#16
Abdou Tchoukoua, Takuma Suzuki, Nanang Rudianto Ariefta, Takuya Koseki, Yusuke Okawa, Ken-Ichi Kimura, Yoshihito Shiono
A new eremophilane sesquiterpene, 13,13-dimethoxyintegric acid (1), together with known compound integric acid (2) have been isolated from a fungus, Xylaria sp. V-27, obtained from a dead branch. The structure of 1 was established by means of spectroscopic analyses. 1 and 2 promoted growth restoring activity against the mutant yeast strain (Saccharomyces cerevisiae (zds1Δ erg3Δ pdr1Δ pdr3Δ)) and inhibited degranulation of rat basophilic leukemia RBL-2H3 cells stimulated by immnunoglobulin G + 2,4-dinitrophenylated-bovine serum albumin (IgE+DNP-BSA), thapsigargin and A23187...
October 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066794/enantiospecific-total-synthesis-of-the-squalene-synthase-inhibitors-cj-13-982-and-its-enantiomer-from-a-common-intermediate
#17
Dayna Sturgess, Zongjia Chen, Jonathan M White, Mark A Rizzacasa
The total syntheses of both the natural and unnatural enantiomers of the alkyl citrate natural product CJ-13,982 (1) from the common d-ribose-derived acid 6 are described.The Journal of Antibiotics advance online publication, 25 October 2017; doi:10.1038/ja.2017.127.
October 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066793/phenazine-carboxylic-acid-and-its-derivative-induce-osteoblast-differentiation-in-preosteoblastic-mc3t3-e1-cells-but-adipocyte-differentiation-in-pluripotent-mesenchymal-c3h10t1-2-cells
#18
Shuichi Sakamoto, Takumi Watanabe, Yasuko Kohda, Masatomi Iijima, Ryuichi Sawa, Maiko Okada, Hayamitsu Adachi, Yoshio Nishimura, Manabu Kawada
Osteoblast and adipocyte are differentiated from mesenchymal stem cells and dysregulation of the differentiation might result in disease, such as osteoporosis and diabetes. To find small compounds that induce osteoblast differentiation, we screened an in-house natural compounds library with mouse preosteoblastic MC3T3-E1 cells using alkaline phosphatase (ALP) expression as an early osteoblast marker. We found that phenazine-1-carboxylic acid (PCA), one of the major phenazine derivatives produced by Pseudomonas, induced osteoblast differentiation in the cells at micromolar concentrations...
October 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066792/lanostane-triterpenoids-from-fruiting-bodies-of-basidiomycete-stereum-sp-structures-and-biological-activities
#19
Jian-Neng Yao, Lin Chen, Yang Tang, He-Ping Chen, Zhen-Zhu Zhao, Zheng-Hui Li, Tao Feng, Ji-Kai Liu
Twelve new lanostane triterpenoids, sterenoids A-L (1-12) have been isolated from fruiting bodies of the basidiomycete Stereum sp. Compounds 1-12 are rare 14(13→︀12)abeo-lanostane triterpenoids featuring remarkable 13R configurations that discriminate from the previously covered counterparts. Their structures and absolute configurations are assigned on the basis of in-depth one- and two-dimensional NMR spectroscopic analysis, as well as unbiased quantum chemical NMR and electronic CD calculations. All isolates are evaluated for their in vitro cytotoxicity against five human tumor cell lines...
October 25, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/29066791/amycolatopsins-a-c-antimycobacterial-glycosylated-polyketide-macrolides-from-the-australian-soil-amycolatopsis-sp-mst-108494
#20
Zeinab G Khalil, Angela A Salim, Daniel Vuong, Andrew Crombie, Ernest Lacey, Antje Blumenthal, Robert J Capon
A southern Australian soil isolate, Amycolatopsis sp. MST-108494, was subjected to a panel of fermentation and media optimization trials, supported by analytical chemical profiling, to detect and enhance production of a rare class of secondary metabolites. Chemical fractionation of two complementary fermentations yielded three new polyketides, identified by detailed spectroscopic analysis as the glycosylated macrolactones, amycolatopsins A (1), B (2) and C (3), closely related to the ammocidins and apoptolidins...
October 25, 2017: Journal of Antibiotics
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