(±)-Usphenethylones A−C, three pairs of heterodimeric polyketide enantiomers from Aspergillus ustus 3.3904

Author(s):  
Hanli Ruan ◽  
Xiaogang Peng ◽  
Shuang Zhou ◽  
Junjun Liu ◽  
Ying Gao ◽  
...  

Three pairs of novel heterodimeric polyketide enantiomers, (±)-usphenethylones A−C (1−3), were isolated from the culture extract of Aspergillus ustus 3.3904. Compounds 1−3 represent two unique heterodimerization patterns of a phenethyl...

Marine Drugs ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 229
Author(s):  
Young Eun Du ◽  
Eun Seo Bae ◽  
Yeonjung Lim ◽  
Jang-Cheon Cho ◽  
Sang-Jip Nam ◽  
...  

Two new secondary metabolites, svalbamides A (1) and B (2), were isolated from a culture extract of Paenibacillus sp. SVB7 that was isolated from surface sediment from a core (HH17-1085) taken in the Svalbard archipelago in the Arctic Ocean. The combinational analysis of HR-MS and NMR spectroscopic data revealed the structures of 1 and 2 as being lipopeptides bearing 3-amino-2-pyrrolidinone, d-valine, and 3-hydroxy-8-methyldecanoic acid. The absolute configurations of the amino acid residues in svalbamides A and B were determined using the advanced Marfey’s method, in which the hydrolysates of 1 and 2 were derivatized with l- and d- forms of 1-fluoro-2,4-dinitrophenyl-5-alanine amide (FDAA). The absolute configurations of 1 and 2 were completely assigned by deducing the stereochemistry of 3-hydroxy-8-methyldecanoic acid based on DP4 calculations. Svalbamides A and B induced quinone reductase activity in Hepa1c1c7 murine hepatoma cells, indicating that they represent chemotypes with a potential for functioning as chemopreventive agents.


2020 ◽  
Vol 164 ◽  
pp. 06015
Author(s):  
Kseniia Illarionova ◽  
Sergey Grigoryev

The aim of research was to characterize epiphyte micromycetes observed on variable cotton fibers accessions, to estimate the range of fiber destruction and select cotton, which were the most resistant to fungus damage. The accessions of differently colored Upland Cotton varieties (Gossypium hirsutum L.) evaluated: eleven cotton of natural green, twelve – of brown and eleven of conventional white color. Cotton plants have been grown in Sothern Federal District, RF. The fiber samples for the study were placed into a thermostat in sterile Petri dishes on moistened filter paper in order to stimulate the development of mycelium or sporulation of fungi naturally occurred on fibers. Incubation carried out in a thermostat at a +24-28 °C, humidity of 90-100% and exposed for 28 days. The samples examined with a microscope or binocular magnifier. Aspergillus ustus (Bainier), A. fumigatus Fresen., A. niger v. Tiegh., A. flavus Link, Penicillium aurantiogriseum Dierckx, P. notatum Westling, Rhizopus nigricans Ehrenb. and Alternaria alternata (Fuier) Keissler were detected. Compared with exposed white, accession of green and brown colors were significantly resistant to fungus. The mean of destruction (K) of white cotton varied up to 0.95, but colored accessions not exceeded 0.3 (initial destruction of the surface, not affecting internal fiber’s structure).


1946 ◽  
Vol 68 (4) ◽  
pp. 725-726 ◽  
Author(s):  
W. E. Doering ◽  
R. J. Dubos ◽  
D. S. Noyce ◽  
R. Dreyfus

Author(s):  
Salman A. Ahmed ◽  
Fiona E. Scott ◽  
Desmond J. Stenzel ◽  
Thomas J. Simpson ◽  
Richard N. Moore ◽  
...  
Keyword(s):  

ChemInform ◽  
2010 ◽  
Vol 27 (47) ◽  
pp. no-no
Author(s):  
M. A. HAYES ◽  
S. K. WRIGLEY ◽  
I. CHETLAND ◽  
E. E. REYNOLDS ◽  
A. M. AINSWORTH ◽  
...  

2016 ◽  
Vol 68 (2) ◽  
pp. 279-289 ◽  
Author(s):  
Jelena Jovicic-Petrovic ◽  
Sanja Jeremic ◽  
Ivan Vuckovic ◽  
Sandra Vojnovic ◽  
Aleksandra Bulajic ◽  
...  

Adding compost to soil can result in plant disease suppression through the mechanisms of antagonistic action of compost microflora against plant pathogens. The aim of the study was to select effective antagonists of Pythium aphanidermatum from compost, to assess the effect of its extracellular metabolites on the plant pathogen, and to characterize antifungal metabolites. The fungal isolate selected by a confrontation test was identified as Aspergillus piperis A/5 on the basis of morphological features and the internal transcribed spacer (ITS) region, ?-tubulin and calmodulin partial sequences. Liquid chromatography-mass spectroscopy (LC-MS) analysis showed that gluconic and citric acid were the most abundant in the organic culture extract. However, the main antifungal activity was contained in the aqueous phase remaining after the organic solvent extraction. The presence of considerable amounts of proteins in both the crude culture extract as well as the aqueous phase remaining after solvent extraction was confirmed by SDS-PAGE. Isolated Aspergillus piperis A/5 exhibits strong antifungal activity against the phytopathogen Pythium aphanidermatum. It secretes a complex mixture of metabolites consisting of small molecules, including gluconic acid, citric acid and itaconic acid derivatives, but the most potent antifungal activity was associated with proteins resistant to heat and organic solvents. Our findings about the activity and characterization of antagonistic strain metabolites contribute to the understanding of the mechanism of interaction of antifungal metabolites as well as fungal-fungal interaction. The obtained results provide a basis for further application development in agriculture and food processing.


Author(s):  
Z. Kozakiewicz

Abstract A description is provided for Aspergillus ustus. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Found in all soil types (DOMSCH et al., 1980), but also isolated from radio equipment, polyurethane foam, flannel bag, sugar and fermented cocoa (CABI BIOSCIENCE, 1999). DISEASE: On man it has been implicated in a case of primary cutaneous infection following a liver transplant (STILLER et al., 1994), isolated from invasive aspergillosis (VERWEU et al., 1999) and disseminated aspergillosis (IWEN et al., 1998). GEOGRAPHICAL DISTRIBUTION: World-wide, but with preference for tropical and subtropical regions.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Liujuan Zheng ◽  
Haowen Wang ◽  
Aili Fan ◽  
Shu-Ming Li

Abstract Oxepinamides are derivatives of anthranilyl-containing tripeptides and share an oxepin ring and a fused pyrimidinone moiety. To the best of our knowledge, no studies have been reported on the elucidation of an oxepinamide biosynthetic pathway and conversion of a quinazolinone to a pyrimidinone-fused 1H-oxepin framework by a cytochrome P450 enzyme in fungal natural product biosynthesis. Here we report the isolation of oxepinamide F from Aspergillus ustus and identification of its biosynthetic pathway by gene deletion, heterologous expression, feeding experiments, and enzyme assays. The nonribosomal peptide synthase (NRPS) OpaA assembles the quinazolinone core with d-Phe incorporation. The cytochrome P450 enzyme OpaB catalyzes alone the oxepin ring formation. The flavoenzyme OpaC installs subsequently one hydroxyl group at the oxepin ring, accompanied by double bond migration. The epimerase OpaE changes the d-Phe residue back to l-form, which is essential for the final methylation by OpaF.


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