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Journal of Antibiotics

Xiang-Mei Tan, Lu-Ying Li, Li-Yan Sun, Bing-Da Sun, Shu-Bin Niu, Meng-Hua Wang, Xiao-Yan Zhang, Wen-Song Sun, Gui-Shan Zhang, Hui Deng, Xiao-Ke Xing, Zhong-Mei Zou, Gang Ding
Endophytic fungi from desert, arid, and grassland areas are an ecologically important but unique group with poor chemical investigation. During our ongoing study to mine bioactive secondary metabolites from unique fungal environments, a new shunt product spiciferone F (1) including two new analogs spiciferones G (2) and H (3) together with four known ones spiciferone A (4), spiciferol A (5), 6, and 7 were isolated from endophytic fungus Phoma betae inhabiting in plant Kalidium foliatum (Pall.) Moq from Ningxia Province of West China...
March 14, 2018: Journal of Antibiotics
Shotaro Hoshino, Chin Piow Wong, Masahiro Ozeki, Huiping Zhang, Fumiaki Hayashi, Takayoshi Awakawa, Shumpei Asamizu, Hiroyasu Onaka, Ikuro Abe
New polycyclic tetramate macrolactams, Umezawamides A (1) and B (2) were isolated from a combined-culture of Umezawaea sp. RD066910 and mycolic-acid containing bacterium Tsukamurella pulmonis TP-B0596. Their planar structures and partial stereochemistries were determined based on the spectroscopic analysis, MMFF conformational search, and ECD calculations. Umezawamides are the first secondary metabolites isolated from the genus Umezawaea and they exhibited cytotoxicities to P388 murine leukemia cells. Furthermore, umezawamide A (1) showed growth inhibitory activity against Candida albicans...
March 14, 2018: Journal of Antibiotics
Marilize Le Roes-Hill, Kim Durrell, Alaric Prins, Paul R Meyers
The actinobacterium, strain M26T , was isolated from garden soil that was pre-treated with microwave radiation. The soil sample was collected in Roodepoort, Gauteng Province, South Africa as part of an antibiotic-screening programme. The isolate produced branched vegetative mycelium with sporangiophores bearing small sporangia ranging from 3 to 6 μm in diameter. Rapid genus identification revealed that the isolate belongs to the genus Streptosporangium. To confirm this result, the strain was subjected to polyphasic taxonomic characterisation...
March 7, 2018: Journal of Antibiotics
Tōru Kimura, Yuki Inahashi, Hirotaka Matsuo, Takuya Suga, Masato Iwatsuki, Kazuro Shiomi, Yōko Takahashi, Satoshi Ōmura, Takuji Nakashima
Two new antibiotics, designated pyrizomicin A and B, were isolated from the cultured broth of a rare actinomycete strain, Lechevalieria aerocolonigenes K10-0216, by silica gel and HPLC purification. The chemical structures of pyrizomicin A and B were elucidated as new thiazolyl pyridine compounds by nuclear magnetic resonance and mass spectrometry. Pyrizomicin A and B both showed antimicrobial activity.
March 7, 2018: Journal of Antibiotics
Hiroaki Gouda, Naofumi Nakayama, Tomoaki Miura, Kenichi Kanemoto, Keiichi Ajito
Formation of 15-membered azalactone by double reductive amination was analyzed using molecular mechanics and density functional theory calculations for simplified model compounds. As a result, the following aspects were clarified. When methylamine attacks a linear bis-aldehyde in the first step, there are possibilities that two regioisomers are formed. However, one of them exhibited remarkably stable energy level compared with the other. The stable isomer indicated a short distance between a methylamine moiety and an unreacted aldehyde...
March 7, 2018: Journal of Antibiotics
Sheng Tao Bo, Zi Fei Xu, Li Yang, Ping Cheng, Ren Xiang Tan, Rui Hua Jiao, Hui Ming Ge
Mayamycin B, a new antibacterial type II polyketide, together with its known congener mayamycin A, were isolated from Streptomyces sp. 120454. The structure of new compound was elucidated by extensive spectroscopic analysis and comparison with literature data. Sequencing and bioinformatics analysis revealed the biosynthetic gene cluster for mayamycins A and B.
March 7, 2018: Journal of Antibiotics
Bee Gek Ng, Jae Woo Han, Dong Wan Lee, Gyung Ja Choi, Beom Seok Kim
Hahella chejuensis MB-1084 is a Gram-negative marine bacterial strain that produces unusual 17-membered carbocyclic tetraenes, chejuenolide A and B. Two fosmid clones responsible for chejuenolide production were identified from the genomic DNA library of the MB-1084 strain. Systematic inactivation of the open reading frames (ORFs) in the sequenced region defines the boundaries of the chejuenolide (che) biosynthetic gene cluster (24.9 kbp) that encodes one non-ribosomal peptide synthase (NRPS)-polyketide synthase (PKS) hybrid protein, three modular PKSs, two PKS domains, and an amine oxidase homolog...
February 26, 2018: Journal of Antibiotics
Subhash Yadav, Radha Vaddavalli, Srinivas Siripuram, Ramaprasad Veera Venkata Eedara, Shivani Yadav, Ojha Rabishankar, Tushar Lodha, Sasikala Chintalapati, VenkataRamana Chintalapati
An antibiotic producing novel Planctomycete strain, designated JC280T , was isolated from the surface of the plant Hydrilla verticillata collected from an alkaline lake (Buffalo lake), University of Hyderabad, Hyderabad, India. The morphological and chemotaxonomic properties of strain JC280T were in agreement with the characteristics of the genus Planctopirus. The cell shape was spherical to ovoid and some were tear drop shaped. The cells were Gram-stain-negative divided by budding presenting stalks and rosette formation and were non-sporulating...
February 21, 2018: Journal of Antibiotics
Alain S Leutou, Inho Yang, Tu Cam Le, Dongyup Hahn, Kyung-Min Lim, Sang-Jip Nam, William Fenical
A new 14-membered macrolactam natural product, fluvirucin B6 (1), was isolated from a marine-derived actinomycete, Nocardiopsis sp. CNQ-115, via HPLC-UV guided isolation. The chemical structure of 1 was elucidated by 1D and 2D NMR spectroscopic data analysis. Compound 1 showed a weak activity against Gram-positive bacteria, whereas it was inactive against Gram-negative bacteria.
February 21, 2018: Journal of Antibiotics
Francisco R Fields, Katelyn E Carothers, Rashna D Balsara, Victoria A Ploplis, Francis J Castellino, Shaun W Lee
Bacteriocins hold unprecedented promise as a largely untapped source of antibiotic alternatives in the age of multidrug resistance. Here, we describe the first approach to systematically design variants of a novel AS-48 bacteriocin homologue, which we have termed safencin AS-48, from Bacillus safensis, to gain insights into engineering improved activity of bacteriocins. A library of synthetic peptides in which systematic amino acid substitutions to vary the periodicity and abundance of polar, acidic, aliphatic, and hydrophobic residues were generated for a total of 96 novel peptide variants of a single bacteriocin candidate...
February 20, 2018: Journal of Antibiotics
Jin-Soo Park, Tran Hong Quang, Chi-Su Yoon, Hye Jin Kim, Jae Hak Sohn, Hyuncheol Oh
Two new meroterpenoid-type fungal metabolites, furanoaustinol (1) and 7-acetoxydehydroaustinol (2), were isolated from the ethyl acetate extract of a marine-derived fungal strain Penicillium sp. SF-5497, along with eight (3-10) known meroterpenoids. Their structures were elucidated mainly based on the analysis of their NMR (1D and 2D) and MS data. Particularly, the novel meroterpenoid, furanoaustinol (1), belonging to the austin group, was identified to possess an unprecedented hexacyclic ring system. Biological evaluation of these compounds revealed that furanoaustinol (1) weakly inhibited the activity of protein tyrosine phosphatase 1B in a dose-dependent manner with an IC50 value of 77...
February 20, 2018: Journal of Antibiotics
Shoko Izuta, Shohei Kosaka, Makoto Kawai, Rei Miyano, Hirotaka Matsuo, Atsuko Matsumoto, Kenichi Nonaka, Yōko Takahashi, Satoshi Ōmura, Takuji Nakashima
In a search for compounds interacting with ergosterol resin, a new compound named dipyrimicin B was isolated from a rare actinomycete strain, Amycolatopsis sp. K16-0194. In addition, another analog, dipyrimicin A, which does not interact with the resin, was also discovered. The structures of the two dipyrimicins were established by comprehensive 1D and 2D NMR and MS analyses and found to contain a unique core structure, a 2,2'-bipyridine skeleton. Dipyrimicin A showed strong antimicrobial and cytotoxic activity, whereas dipyrimicin B displayed distinctly poor antimicrobial and cytotoxic activities...
February 20, 2018: Journal of Antibiotics
Karolina Klesiewicz, Elżbieta Karczewska, Paweł Nowak, Iwona Skiba-Kurek, Edward Sito, Katarzyna Pańczyk, Paulina Koczurkiewicz, Dorota Żelaszczyk, Elżbieta Pękala, Anna M Waszkielewicz, Alicja Budak, Henryk Marona, Agnieszka Gunia-Krzyżak
In this study, thirty-five N-substituted derivatives of cinnamic acid amide (cinnamamide) were evaluated for anti-Helicobacter pylori activity using an agar disc-diffusion method. Qualitative screening was performed on a reference H. pylori strain (ATCC 43504), resulting in the identification of the three most active compounds, 8 (R,S-(2E)-3-(4-chlorophenyl)-N-(2-hydroxypropyl)prop-2-enamide, minimal inhibitory concentration, MIC = 7.5 µg/mL), 23 ((2E)-3-(4-chlorophenyl)-N-(2-hydroxycyclohexyl)prop-2-enamide, MIC = 10 µg/mL), and 28 ((2E)-3-(4-chlorophenyl)-N-(4-oxocyclohexyl)prop-2-enamide, MIC = 10 µg/mL)...
February 13, 2018: Journal of Antibiotics
Li Liu, Ruixing Liu, Buddha Bahadur Basnet, Li Bao, Junjie Han, Long Wang, Hongwei Liu
Three new bisabolane sesquiterpenoid esters, aspertenols A-B (1-3), and six known compounds (4-9) were isolated from the fungus Aspergillus tennesseensis. The structures of new compounds were elucidated by extensive spectroscopic analysis. The cytotoxicities of 1-9 against A549, K562, and ASPC cell lines were tested by using the CCK8 method. Compounds 1, 3, 4, 6, 7, and 9 showed inhibition on K562 cell line with IC50 values in the range from 16.6 to 72.7 μM. Compounds 1, 4, and 9 showed moderate inhibitory activity against A549 with IC50 of 43...
February 7, 2018: Journal of Antibiotics
Ni Wentao, Li Guobao, Zhao Jin, Cui Junchang, Wang Rui, Gao Zhancheng, Liu Youning
This study assessed the in vitro antibacterial activity of minocycline-aminoglycoside combination against Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae. Seventy non-duplicate clinical isolates of KPC-producing K. pneumoniae were collected from patients with bloodstream infections. The synergistic activity of minocycline-aminoglycoside combination was studied by the checkerboard method and time-kill assays in strains with different susceptibilities, and the mutant prevention concentration (MPC) and mutant selection window (MSW) of drugs alone and in combination were determined...
February 7, 2018: Journal of Antibiotics
Vishvanath Tiwari, Monalisa Tiwari, Deepika Biswas
Acinetobacter baumannii is one of the ESKAPE pathogen, which causes pneumonia, urinary tract infections, and is linked to high degree of morbidity and mortality. One-way antibiotic and disinfectant resistance is acquired by the activation of RecA-mediated DNA repair (SOS-response) that maintain ROS-dependent DNA damage caused by these anti-bacterial molecules. To increase the efficacy of different anti-microbial, there is a need to design an inhibitor against RecA of A. baumannii. We have performed homology modeling to generate the structure of RecA, followed by model refinement and validation...
February 6, 2018: Journal of Antibiotics
Belgin Dogan, Jing Fu, Shiying Zhang, Ellen J Scherl, Kenneth W Simpson
Escherichia coli with an adherent and invasive pathotype (AIEC) is implicated in the pathogenesis of Crohn's disease (CD). Rifaximin improves symptoms in mild-to-moderate CD. It is unclear if this outcome is due to its effects on bacteria or intestinal epithelial inflammatory responses. We examined the effects of rifaximin on the growth and virulence of CD-associated E. coli and intestinal epithelial inflammatory responses. Seven well-characterized CD-associated E. coli strains (six AIEC, one non-AIEC; four rifaximin-resistant, three sensitive) were evaluated...
February 6, 2018: Journal of Antibiotics
Hiroshi Takagi, Toshihiko Nogawa, Yushi Futamura, Shunji Takahashi, Hiroyuki Osada
A new anthraquinone derivative, kinanthraquinone (1) was isolated from Streptomyces reveromyceticus SN-593-44. Its structure was determined by the combination of spectroscopic methods including NMR and MS. Kinanthraquinone had a characteristic carboxamide group and was a rare class of metabolite as an anthraquinone derivative isolated from microbes. It showed moderate cytotoxocity against HL-60 and srcts-NRK cell with IC50 value of 7.9 and 10 μM, respectively.
February 6, 2018: Journal of Antibiotics
Kunimoto Hotta, Shinichi Kondo
On the occasion of the 60th anniversary of the discovery (1957) of kanamycin (KM), a series of research achievements on KM and its semisynthetic derivative Arbekacin (ABK) are outlined. KM was first used clinically in 1958 and was appreciated for its remarkable curing effect on various bacterial infections, especially tuberculosis. ABK is a KM derivative rationally semisynthesized to overcome KM resistance due to enzymatic phosphorylation and acetylation. Since its approval in 1990 as an anti-MRSA drug, ABK has been and still is effectively used in chemotherapy because MRSA rarely develops high ABK-resistance...
February 5, 2018: Journal of Antibiotics
Hua Chen, Kezhou Cai, Risheng Yao
A new macrolactam derivative, designated as nivelactam B (1), was isolated from the fermentation broth of marine-derived actinomycete HF-11225. 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 weak cytotoxic and antifungal activities.
February 5, 2018: Journal of Antibiotics
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