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Journal of Antibiotics

Jinhua Zhang, Jie Ma, Yuanzhen Dong, Wenjie Zhao, Jun Feng
To find novel amphotericin B (AmB) derivatives with high therapeutic potential, low toxicity, and water solubility, a series of nine N-substituted AmB derivatives were evaluated for their antifungal activity using the broth dilution method and for their hemolytic toxicity with sterile defibrinated sheep blood. Qualitative screening of the effect of the derivatives on two reference Candida albicans strains and of their solubility was performed based on the value of n (n is a positive integer), resulting in the identification of an optimal compound, NH2 -(AEEA)5 -AmB (DMR005; AEEA is 8-amino-3,6- dioxaoctanoic acid)...
January 11, 2019: Journal of Antibiotics
Rukshana Mohamad-Ramshan, Pamoda B Ratnaweera, David E Williams, E Dilip de Silva, Raymond J Andersen
Culture feeding experiments with [1-13 C]-acetate, [2-13 C]- acetate, and [1,2-13 C]-acetate have shown that the steroid ring B contraction involved in the biogenesis of the unprecedented carbon skeleton of the antibiotic solanioic acid (1) by the fungus Rhizoctonia solani involves cleavage of the C-5/C-6 bond. The study revealed that 9-epi-solanioic acid (4), which spontaneously converts to solanioic acid (1), is also produced by the cultures and it may be the actual natural product.
January 11, 2019: Journal of Antibiotics
Taehui Yang, Katsuhisa Yamada, Tao Zhou, Enjuro Harunari, Yasuhiro Igarashi, Takeshi Terahara, Takeshi Kobayashi, Chiaki Imada
In our screening program on marine-derived actinomycetes, Nonomuraea sp. AKA32 isolated from deep-sea water collected from a depth of 800 m in Sagami Bay, Japan was found to produce compounds cytotoxic to cancer cells. Activity-guided purification led to the isolation of a new aromatic polyketide, akazamicin (1), along with two known compounds, actinofuranone C (2) and N-formylanthranilic acid (3). Structures of these compounds were elucidated through the interpretation of NMR and MS spectroscopic data. Compounds 1, 2, and 3 displayed cytotoxicity against murine B16 melanoma cell line with the IC50 value of 1...
January 10, 2019: Journal of Antibiotics
Meng Wang, Jittra Kornsakulkarn, Kitlada Srichomthong, Tao Feng, Ji-Kai Liu, Masahiko Isaka, Chawanee Thongpanchang
Five new anthraquinones, morakotins A-E (1-5), together with seven known compounds, lunatin (6), rheoemodin (7), YM187781 (8), bislunatin (9), 6-(1-hydroxypentyl)-4-methoxypyran-2-one, 9,11-dehydoergrosterol peroxide, and cerevisterol, were isolated from the insect pathogenic fungus Cordyceps morakotii BCC 56811. The morakotin structures were elucidated from NMR spectroscopic and mass spectrometric data. The absolute configurations of bianthraquinone compounds, morakotins C-E (3-5), were determined by application of the exciton chirality method...
January 9, 2019: Journal of Antibiotics
Manabu Yamasaki, Masayuki Igarashi, Ryuichi Sawa, Chisato Nosaka, Maya Umekita, Masaki Hatano, Tomoyuki Kimura, Kiyoko Iijima, Naoki Takizawa, Taira Kato, Kiyohisa Mizumoto, Akio Nomoto
Influenza virus RNA polymerase has cap-dependent endonuclease activity that produces capped RNA fragments for priming viral mRNA synthesis. This enzymatic activity is essential for viral propagation, but it is not present in any host cellular enzyme, making it an attractive target for the development of anti-influenza drugs. Here, we isolated a novel inhibitor of cap-dependent endonuclease, named flupyranochromene, from the fermentation broth of the fungus Penicillium sp. f28743. Structural analysis revealed that this compound bears a putative pharmacophore that chelates divalent metal ion(s) present in the endonuclease active site in the PA subunit of the polymerase...
January 9, 2019: Journal of Antibiotics
Noah A Setterholm, Frank E McDonald
We describe a novel strategy for synthesizing the CD bicyclic ether substructure of the fused polycyclic ether natural product brevenal. This product arises from a three-step sequence beginning with (1) regio- and diastereoselective iodoetherification of an acyclic diene-diol, followed by (2) alkene metathesis with an epoxyalkene synthon, concluding with (3) palladium-catalyzed cycloisomerization. Despite the modest yield and long reaction period for the cycloisomerization step, these studies provide valuable insights into the nature of byproducts generated and the mechanisms by which they form...
January 4, 2019: Journal of Antibiotics
Zhijun Yang, Lei Shao, Meixia Wang, Min Rao, Mei Ge, Yixin Xu
Two novel quinomycins I (1) and J (3) were discovered by UPLC-MS, then the two novel compounds and five known quinomycins A(2), B(4), E(5), C(6) and monosulfoxide quinomycin (7) were isolated from the culture broth of Streptomyces sp. HCCB11876. The structures of these compounds were elucidated through MS and NMR spectroscopic analysis. Compounds 1-7 showed significant antibacterial and cytotoxic activities. The structure-activity relationship indicated that sulfoxide group in N-methylcysteine of quinomycins (1, 3 and 7) would significantly decrease the antibacterial and cytotoxic activities...
December 18, 2018: Journal of Antibiotics
Masahiko Isaka, Arunrat Yangchum, Sumalee Supothina, Sukitaya Veeranondha, Somjit Komwijit, Souwalak Phongpaichit
Derivatives of the fungal depsidone, nidulin, have been synthesized in order to evaluate the potential of the chemical skeleton as antibacterial agents. Alkylation, acylation, and arylation reactions of nornidulin underwent in a regioselective manner to predominantly produce 8-O-substituted derivatives. Many of the semisynthetic derivatives showed more potent antibacterial activities than nidulin, In particular, 8-O-aryl ether derivatives displayed significant activities against Gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus...
December 17, 2018: Journal of Antibiotics
E-Eum Woo, Ji-Yul Kim, Jeong-Seon Kim, Soon-Wo Kwon, In-Kyoung Lee, Bong-Sik Yun
To discover antimicrobial agents from higher fungi, mannonerolidol (3), a new nerolidol mannoside, together with known schizostatin (1) and nerolidol (2) were isolated from an antimicrobial fraction of the culture broth of Schizophyllum commune. Structures of these compounds were determined through spectroscopic methods. Compounds 1 and 3 exhibited antimicrobial activities against plant pathogenic fungi Rhizoctonia solani, Diaporthe sp., Botrytis cinerea, and Alternaria solani and bacteria Bacillus subtilis and Staphylococcus aureus...
December 12, 2018: Journal of Antibiotics
Jung Wha Kim, Hyun Gyu Choi, Ji Hoon Song, Ki Sung Kang, Sang Hee Shim
Two new isochromanone derivatives, (3S,4S)-3,8-dihydroxy-6-methoxy-3,4,5-trimethylisochroman-1-one (1) and methyl (S)-8-hydroxy-6-methoxy-5-methyl-4a-(3-oxobutan-2-yl)benzoate (2), together with six known compounds (3‒8) were isolated from the cultures of an endophytic fungus Phoma sp. PF2 obtained from Artemisia princeps. The chemical structures of the isolated compounds were elucidated by interpretation of spectroscopic data (1D, 2D NMR, HRESIMS, and CD) and calculation of ECD. All the isolated compounds (1‒8) showed moderate inhibitory activities on nitric oxide levels in lipopolysaccharide-induced RAW264...
December 12, 2018: Journal of Antibiotics
Tōru Kimura, Takuya Suga, Masanori Kameoka, Minoru Ueno, Yuki Inahashi, Hirotaka Matsuo, Masato Iwatsuki, Katsumi Shigemura, Kazuro Shiomi, Yōko Takahashi, Satoshi Ōmura, Takuji Nakashima
Two new antibiotics, designated virantmycin B (1) and C (2), were isolated from the cultured broth of Streptomyces sp. AM-2504. Compounds 1 and 2 were purified by Diaion HP-20, silica gel, and octadecylsilane chromatography, followed by high-performance liquid chromatography. The chemical structures of the new compounds, 1 and 2, were determined by nuclear magnetic resonance and mass spectrometry, as containing a terahydroquinoline and an indoline, respectively, each also containing a hydroxy cyclopentenone moiety...
December 10, 2018: Journal of Antibiotics
Ryuji Uchida, Ariko Kondo, Akiho Yagi, Kenichi Nonaka, Rokurou Masuma, Keisuke Kobayashi, Hiroshi Tomoda
Simpotentin, a new potentiator of amphotericin B activity against Candida albicans and Cryptococcus neoformans, was isolated from the culture broth of Simplicillium minatense FKI-4981 by Diaion HP-20 column chromatography, centrifugal partition chromatography, and preparative HPLC. The structure of simpotentin was elucidated by spectroscopic analyses including NMR and MS. The compound has a mannose core to which two medium-chain fatty acids are linked. Simpotentin was found to potentiate amphotericin B activity against C...
December 10, 2018: Journal of Antibiotics
Yinzhi Lin, Yue Chen, Tamami Ukaji, Shoshiro Okada, Kazuo Umezawa
Inhibitors of cancer cell migration and invasion should be useful to inhibit metastasis. Then, we have screened microbial culture filtrates for the inhibitors of cancer cell migration. As a result, we isolated an antibiotic ketomycin from a culture filtrate of Actinomycetes SF2912 as an inhibitor of cancer cell migration. It is a known antibiotic, but its biological activity on mammalian cells has not been reported. Ketomycin inhibited cellular migration and invasion in human breast carcinoma MDA-MB-231 and MCF-7 cells at the non-toxic concentrations...
December 3, 2018: Journal of Antibiotics
Vladimir Vimberg, Radek Gazak, Zsolt Szűcs, Aniko Borbás, Pal Herczegh, Jorunn Pauline Cavanagh, Leona Zieglerova, Jan Závora, Václava Adámková, Gabriela Balikova Novotna
Here, we describe a fluorescent assay developed to study competitive binding of the glycopeptide antibiotics to live bacteria cells. This assay demonstrated that the mechanism of action of the lipoglycopeptide antibiotics strongly depends on the hydrophobicity of the substitutes, with the best antibacterial activity of the glycopeptide antibiotics equally sharing properties of binding to D-Ala-D-Ala residues of the nascent peptidoglycan and to the membrane.
November 30, 2018: Journal of Antibiotics
Alexey A Panov, Sergey N Lavrenov, Alexander Y Simonov, Elena P Mirchink, Elena B Isakova, Alexey S Trenin
A series of 3,4-bis(arylthio)maleimides were synthesized and their antimicrobial activity was evaluated against Gram-positive and Gram-negative bacteria, including multidrug resistant (MDR) strains and some fungi. Most compounds turned out to be highly active, activity being dependent on substituents on phenyl rings.
November 28, 2018: Journal of Antibiotics
Jhessyca Leal Melgarejo, Marlon Henrique Cardoso, Ingrid Batista Pinto, Célio Faria-Junior, Sónia Mendo, Carina Elisei de Oliveira, Octavio Luiz Franco
NDM-1 comprises a carbapenemase that was first detected in 2008 in New Delhi, India. Since then, NDM-1-producing Klebsiella pneumoniae strains have been reported in many countries and usually associated with intra and inter-hospital dissemination, along with travel-related epidemiological links. In South America, Brazil represents the largest reservoir of NMD-1-producing K. pneumoniae. Here, we focused on the detection and molecular/structural characterization of the blaNDM-1 resistance gene/enzyme from 24 K...
November 27, 2018: Journal of Antibiotics
Shufen Li, Xinxin Hu, Linli Li, Hongyu Liu, Liyan Yu, Xuefu You, Bingya Jiang, Linzhuan Wu
Geninthiocin is a thiopeptide with 35-membered macrocyclic core moiety. It has potent anti-Gram-positive (G+ ) bacteria activity. Herein, we reported two new congeners (2-3) of geninthiocin (geninthiocin A, 1) from Streptomyces sp. CPCC 200267, and designated them as geninthiocins C and D, whose structures were determined by NMR. Geninthiocins A, C and D had the same 35-membered macrocyclic core moiety, but possessed a -Dha-Dha-NH2 , -Dha-Ala-NH2 , and -NH2 tail, respectively. Besides, the Ala residue in geninthiocin C was determined as L- configuration by C3 Marfey's method...
November 27, 2018: Journal of Antibiotics
Yassine Zouheir, Taha Atany, Najma Boudebouch
Neisseria meningitidis is one of the most crucial causes of bacterial meningitis worldwide. The incidence of meningitis due to N. meningitidis greatly changes from one geographical area to the other: 500,000-1,200,000 invasive meningococcal diseases occur each year, with 50,000-135,000 deaths. Once the diagnosis of bacterial meningitis is made, parenteral antibiotic treatment is started as soon as possible. A preventive treatment can also be proposed for those subjects at risk of exposure. Globally, resistance to antibiotics used in the treatment of prophylaxis of meningococcal disease is relatively rare...
November 27, 2018: Journal of Antibiotics
Wataru Ichinose, Tsukasa Sawato, Haruna Kitano, Yasuhiro Shinozaki, Mieko Arisawa, Nozomi Saito, Takeo Yoshikawa, Masahiko Yamaguchi
Optically active helicene derivatives inhibit the activity on histamine N-methyl transferase (HNMT). Specifically, methyl (P)-1,12-dimethylbenzo[c]phenanthrene-8-carboxylate with 6-iodo and 5-trifluoromethanesulfonyloxy groups inhibits HNMT activity on the μM order of IC50 . Chirality is important, and (M)-isomers exhibits substantially reduced activity. The 6-iodo group is also essential, which suggests the involvement of halogen bonds in protein binding. Substituents on the sulfonate moiety also affect the inhibitory activity...
November 20, 2018: Journal of Antibiotics
Małgorzata Prażyńska, Eugenia Gospodarek-Komkowska
According to the available literature, echinocandins display high anti-Candida spp. activity. Paradoxical growth (PG) of Candida spp. planktonic cells promoted by echinocandins is widely reported. Here we report on the ability of Candida spp. sessile cells to display PG when they are exposed to caspofungin in vitro, even at relatively low drug concentrations. Clinical significance of PG during echinocandin therapy of candidiasis remains uncertain. We assessed in vitro susceptibilities of Candida spp. sessile cells to caspofungin and analyzed the frequency of PG...
November 19, 2018: Journal of Antibiotics
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