Kenichi Matsuda, Hiroto Maruyama, Kumiko Imachi, Haruo Ikeda, Toshiyuki Wakimoto
Copper is a transition metal element with significant effects on the morphological development and secondary metabolism of actinobacteria. In some microorganisms, copper-binding natural products are employed to modulate copper homeostasis, although their significance in actinobacteria remains largely unknown. Here, we identified the biosynthetic genes of the diisocyanide natural product hazimycin in Kitasatospora purpeofusca HV058, through gene knock-out and heterologous expression. Biochemical analyses revealed that hazimycin A specifically binds to copper, which diminishes its antimicrobial activity...
February 20, 2024: Journal of Antibiotics
So-Ichiro Kimura, Yoshihiro Watanabe, Yudai Mikasa, Rei Miyano, Toshiyuki Tokiwa, Kenichi Nonaka, Takuji Nakashima, Yoshihiko Noguchi, Tomoyasu Hirose, Toshiaki Sunazuka, Rei Hokari, Aki Ishiyama, Masato Iwatsuki
Two new pramanicin analogs, named virgaricins C (1) and D (2), were discovered by physicochemical screening from a static cultured material of Apiospora sp. FKI-8058. Their structures were elucidated by MS and NMR analyses and chemical derivatization. Compounds 1 and 2 showed moderate antimalarial activity and cytotoxicity.
February 2, 2024: Journal of Antibiotics
Luning Zhou, Yimin Chang, Shengkuan Yang, Xiaofei Huang, Jiaxiang Wang, Chengyu Jiang, Tianjiao Zhu, Dehai Li, Qian Che
Assisted by OSMAC strategy, one new p-terphenyl and two new α‑pyrone derivates, namely nocarterphenyl I (1) and nocardiopyrone D-E (2-3), were obtained and characterized from the marine sediment-derived actinomycete Nocardiopsis sp. HDN154086. The structures of these compounds were determined on the basis of MS, NMR spectroscopic data and single-crystal X-ray diffraction. Compound 1 with a rare 2,2'-bithiazole structure among natural products showed promising activity against five bacteria with MIC values ranging from 0...
January 25, 2024: Journal of Antibiotics
Kenichiro Nagai, Keisuke Kobayashi, Ryosuke Miyake, Yukino Sato, Reiko Seki, Takashi Fukuda, Akiho Yagi, Ryuji Uchida, Taichi Ohshiro, Hiroshi Tomoda
Nectriatide 1a, a naturally occurring cyclic tetrapeptide, has been reported to a potentiator of amphotericin B (AmB) activity. In order to elucidate its structure-activity relationships, we synthesized nectriatide derivatives with different amino acids in solution-phase synthesis and evaluated AmB-potentiating activity against Candida albicans. Among them, C-and N-terminal protected linear peptides were found to show the most potent AmB-potentiating activity.
January 24, 2024: Journal of Antibiotics
Hideki Hashizume, Ryuichi Sawa, Yumiko Kubota, Shinya Adachi, Shigeko Harada, Masayuki Igarashi
Tripropeptin C, a non-ribosomal cyclic lipopeptide containing three proline residues, exhibits excellent efficacy in the mouse-methicillin-resistant Staphylococcus aureus septicemia model. Since tripropeptins contain L-prolyl-D-proline and, as a result, are known to form a hairpin structure in proteins, it was of interest to determine whether this substructure contributes to their antibacterial activity. In this study, prolines in tripropeptin C were replaced with pipecolic acid(s) using precursor-directed biosynthesis...
January 24, 2024: Journal of Antibiotics
Haeun Kwon, Hee Woon Ann, Sojung Park, Jaeyoung Kwon, Keunwan Park, Seung Mok Ryu, Yuanqiang Guo, Jae-Jin Kim, Joung Han Yim, Il-Chan Kim, Sang Hee Shim, Sullim Lee, Dongho Lee
Using mass spectrometry (MS)-guided isolation methods, a new thiodiketopiperazine derivative (1) and exserohilone (2) were isolated from an EtOAc-extract of Setosphaeria rostrata culture medium. The chemical structure of the new compound was elucidated by MS and NMR spectroscopy, and the absolute configurations were established by the quantum mechanical calculations of electronic circular dichroism. All isolated compounds were examined for their effects on reactive oxygen species (ROS) production, matrix metalloproteinase 1 (MMP-1) secretion, and procollagen type I α1 secretion in tumor necrosis factor (TNF)-α-induced human dermal fibroblasts...
January 19, 2024: Journal of Antibiotics
Hannah J T Nonarath, Michael A Jackson, Renee M Penoske, Thomas C Zahrt, Neil P J Price, Brian A Link
Tunicamycins (TUN) are well-defined, Streptomyces-derived natural products that inhibit protein N-glycosylation in eukaryotes, and by a conserved mechanism also block bacterial cell wall biosynthesis. TUN inhibits the polyprenylphosphate-N-acetyl-hexosamine-1-phospho-transferases (PNPT), an essential family of enzymes found in both bacteria and eukaryotes. We have previously published the development of chemically modified TUN, called TunR1 and TunR2, that have considerably reduced activity on eukaryotes but that retain the potent antibacterial properties...
January 18, 2024: Journal of Antibiotics
Shuang Yu, Boyan Jia, Ying Zhang, Yue Yu, Zhihua Pei, Hongxia Ma
As the important components of biological innate immunity, antimicrobial peptides (AMPs) were found in a variety of organisms including insects, plants, animals, bacteria, fungi, etc. However, high hemolytic activity, high toxicity, and poor stability of natural AMPs hinder serious their application as therapeutic agents. To overcome these problems, in this study we use PRRP as a central axis, and peptides were designed based on the sequence template XRRXXRXPRRPXRXXRRX-NH2 , where X represents a hydrophobic amino acid like Phe (F), Ile (I), Val (V), and Leu (L)...
January 17, 2024: Journal of Antibiotics
Jun Li, Zhenye Yang, Chuanling Shi, Xiaoyun Wu, Le Zhou, Yongqian Liang, Qinglian Li, Jianhua Ju
Vicenistatin (1) is a 20-membered polyketide macrocyclic antibiotic with potent antimicrobial and cytotoxic activities. In this study, to further explore the potential of 1 as candidates of antibacterial drug development, 4'-N-demethyl vicenistatin (2), a secondary metabolite obtained from the ∆vicG mutant strain of Monodonata labio-associated Streptomyces parvus SCSIO Mla-L010, was utilized as a starting material for modifications of 4'-amino group of vicenistatin. Six new vicenistatin derivatives (3-8) were semi-synthesized through a concise route of amino modification with various aliphatic and aromatic aldehydes...
January 16, 2024: Journal of Antibiotics
Haruki Azami, Yoshihiro Watanabe, Kazunari Sakai, Hiroki Nakahara, Hiroki Kojima, Toshiyuki Tokiwa, Kenichi Nonaka, Yoshihiko Noguchi, Yuriko Nagano, Tomoyasu Hirose, Toshiaki Sunazuka, Hidehito Matsui, Naoaki Arima, Kazutoyo Abe, Hideaki Hanaki, Masato Iwatsuki
A new antifungal compound, named N-demethyltyroscherin (1), was discovered from the static fungal cultured material of Scedosporium apiospermum FKJ-0499 isolated from a deep-sea sediment sample together with a known compound, tyroscherin (2). The structure of 1 was elucidated as a new analog of 2 by MS and NMR analyses. The absolute configuration of 1 was determined by chemical derivatization. Both compounds showed potent in vitro antifungal activity against clinically isolated Candida auris strains, with MIC values ranging from 0...
January 11, 2024: Journal of Antibiotics
Di Mao, Pengwei Yu, Naoya Shinzato, Lei Zhang, Weiping Zheng, Shan Lu, Hideaki Kakeya
A novel antibiotic biosynthetic precursor of cezomycin, named precezomycin (1), was isolated from culture broth of actinomycete Kitasatospora putterlickiae 10-13. The planar structure was determined by 1D/2D NMR and HR(ESI)MS data analyses, and the absolute configurations were established by TDDFT calculation of ECD spectra. Precezomycin (1) exhibited moderate antibacterial activity against gram-positive bacteria including Staphylococcus aureus and Bacillus subtilis. The discovery of 1 extends the natural product family of cezomycin and provides a new insight into understanding the biosynthetic process of these polyether ionophore metabolites...
January 10, 2024: Journal of Antibiotics
Shuhei Umetsu, Takeshi Tsunoda, Haruka Kiyanagi, Yuki Inahashi, Kenichi Nonaka, Tohru Dairi, Yasushi Ogasawara
Peptidoglycan is an important macromolecule in bacterial cell walls to maintain cell integrity, and its biosynthetic pathway has been well studied. Recently, we demonstrated that some bacteria such as Xanthomonas oryzae, a pathogen causing bacterial blight of rice, used an alternative pathway for peptidoglycan biosynthesis. In this pathway, MurD2, a MurD homolog, catalyzed the attachment of L-Glu to UDP-MurNAc-L-Ala and MurL, which did not show homology to any known protein, catalyzed epimerization of the terminal L-Glu of the MurD2 product to generate UDP-MurNAc-L-Ala-D-Glu...
January 10, 2024: Journal of Antibiotics
Masako Honsho, Aoi Kimishima, Akari Ikeda, Masato Iwatsuki, Kenichi Nonaka, Hidehito Matsui, Hideaki Hanaki, Yukihiro Asami, Toshiaki Sunazuka
Antimicrobial resistance (AMR) causes a global health threat and enormous damage for humans. Among them, Methicillin-resistant Staphylococcus aureus (MRSA) resistant to first-line therapeutic β-lactam drugs such as meropenem (MEPM) is problematic. Therefore, we focus on combination drug therapy and have been seeking new potentiators of MEPM to combat MRSA. In this paper, we report the isolation of phomoidrides A-D and its new analog, phomoidride H along with a polyketide compound, oxasetin from the culture broth of Neovaginatispora clematidis FKI-8547 strain as potentiators of MEPM against MRSA...
January 4, 2024: Journal of Antibiotics
Mingkai Zhang, Baosong Chen, Huanqin Dai, Jingzu Sun, Hongwei Liu, Junjie Han
Intestinal fungi, which are important parts of the gut microbiota, have the ability to produce specialized metabolites that significantly contribute to maintaining the balance of the gut microbiota and promoting the health of the host organism. In the present study, two new glycosides, including fusintespyrone A (1) and cerevisterolside A (4), as well as ten known compounds were isolated from the intestinal fungus Fusarium sp. LE06. The structures of the new compounds were elucidated by a combination of spectroscopic methods, such as mass spectrometry (MS) and nuclear magnetic resonance (NMR), along with chemical reactions and calculations of NMR and ECD spectra...
December 26, 2023: Journal of Antibiotics
Le Wang, Yao Xiao, Wenxin Lai, Ru Jia, Qinglin Deng, Xin Wang, Hongqiu Shi, Yiwen Yang, Binghuo Zhang
A novel actinobacterial strain, designated as JXJ CY 30 T , was isolated from the phycosphere of Microcystis aeruginosa FACHB-905 (Maf) collected from Lake Dianchi, China. The strain was a Gram-stain-positive, aerobic and coccus-shaped actinobacterium. It had alanine, glutamic acid, aspartic acid, and lysine in the peptidoglycan, and mannose, ribose and arabinose in its cell wall sugars, anteiso-C15:0 and iso-C15:0 as the main cellular fatty acids, MK-7 and MK-8 as the major respiratory quinones, and phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, glycolipid, and an unidentified phospholipid as the polar lipids...
December 26, 2023: Journal of Antibiotics
Masami Ishibashi
No abstract text is available yet for this article.
December 21, 2023: Journal of Antibiotics
Alison H Araten, Rachel S Brooks, Sarah D W Choi, Laura L Esguerra, Diana Savchyn, Emily J Wu, Gabrielle Leon, Katherine J Sniezek, Mark P Brynildsen
Cephalosporins comprise a β-lactam antibiotic class whose first members were discovered in 1945 from the fungus Cephalosporium acremonium. Their clinical use for Gram-negative bacterial infections is widespread due to their ability to traverse outer membranes through porins to gain access to the periplasm and disrupt peptidoglycan synthesis. More recent members of the cephalosporin class are administered as last resort treatments for complicated urinary tract infections, MRSA, and other multi-drug resistant pathogens, such as Neisseria gonorrhoeae...
December 19, 2023: Journal of Antibiotics
Alastair E Lacey, Scott A Minns, Rachel Chen, Daniel Vuong, Ernest Lacey, John A Kalaitzis, Yu Pei Tan, Roger G Shivas, Mark S Butler, Andrew M Piggott
Talcarpones A (1) and B (2) are rare bisnaphthazarin derivatives produced by Talaromyces johnpittii (ex-type strain MST-FP2594), a newly discovered Australian fungus, which is formally described and named herein. The talcarpones were isolated along with the previously reported monomeric naphthoquinone, aureoquinone (3), suggesting a biosynthetic link between these metabolites. Talcarpone A is a lower homologue of hybocarpone (4), which was first isolated from a mycobiont of the lichen Lecanora hybocarpa. The structures of 1 and 2 were elucidated by detailed spectroscopic analysis, molecular modelling and comparison with literature data...
December 18, 2023: Journal of Antibiotics
Yani Yu, Jia Yu, Xiaorong Cui, Xin Sun, Xiaohui Yu
We aimed to investigate the effects of tumor necrosis factor (TNF)-α on the expression of interferon α/β receptor subunit 1 (IFNAR1) and cervical squamous cancer (CSCC) resistance to Cisplatin, as well as the underlying mechanisms. Kaplan-Meier analysis was used to plot the overall survival curves. SiHa cells were treated with 20 ng/ml TNF-α to determine cell proliferation in human CSCC cells and the expression of IFNAR1. The effects of TNF-α on the downstream signaling pathway, including casein kinase 1α (CK1α), were investigated using the caspase protease inhibitor FK009, the c-Jun kinase inhibitor SP600125, and the nuclear factor kappa-B inhibitor ammonium pyrrolidinedithiocarbamate (PDTC)...
December 15, 2023: Journal of Antibiotics
Keiichi Ajito
No abstract text is available yet for this article.
November 30, 2023: Journal of Antibiotics
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