199 research outputs found
Sponge-associated fungi and their bioactive compounds - the Suberites case
No full textSpecimens of Suberites domuncula that had been cultured in aquaria for 4 weeks were analyzed for their associated fungi. A total of 81 fungal strains belonging to 20 different genera was isolated and identified by morphological and molecular methods. The most frequently isolated taxa were Cladosporium spp., Penicillium spp., Petriella sp., Phialophora spp. and Engyodontium album. Based on chromatographic and mass spectrometric analysis of fungal extracts, as well as on bioassay results, Aspergillus ustus, Penicillium sp., Petriella sp. and Scopulariopsis sp. were selected for in-depth analysis of their natural products. A total of 19 different fungal metabolites, including three new natural products, was isolated and structurally identified. A. ustus yielded two sesquiterpenes, a drimane derivative and deoxyuvidin, as well as a sesterterpene ophiobolin H. The drimane derivative had an ED50 value against L5178Y cells of 1.9 mu g ml(-1) in vitro. The crude extract of Petriella sp. was also strongly cytotoxic against the L5178Y cell line. The cyclic tetrapeptide WF-3161 was primarily responsible for the activity; the ED50 value was <0.1 mu g ml(-1). It was identical to the known compound WF-3161 and had been previously isolated from Petriella guttulata. In addition to WF-3161, three further natural products were obtained and unequivocally identified as new derivatives of infectopyrone by one-and two-dimensional NMR spectroscopy and by mass spectroscopy. Of the new compounds, only dihydroinfectopyrone was active against L5178Y cells; the ED50 value was 0.2 mu g ml(-1). Penicillium sp. yielded the largest number of metabolites. Viridicatin, viridicatol, cyclopenin and cyclopenol suppressed larval growth of the polyphagous pest insect Spodoptera littoralis when incorporated into an artificial diet at an arbitrarily chosen concentration of 237 ppm. Viridicatol was the most active compound and had an ED50 value of ca. 50 ppm. Scopulariopsis sp. yielded three metabolites, including the known acetylcholinesterase inhibitors quinolactacin A1 and A2
Trade finance for sustainable development in Asia and the Pacific
No full textThis discussion paper 'Trade Finance for Sustainable Development in Asia and the Pacific' was prepared for ESCAP by Sailendra Narain, Chairman, Centre for SME Growth and Development Finance, India.
The author would like to express his gratitude and sincere thanks to Mia Mikic, Marc Proksch, Yann L Duval, Masato Abe and Mona Narain for reviewing and editing the paper and providing comments with valuable suggestions
How Developers Engage with Static Analysis Tools in Different Contexts
No full textAutomatic static analysis tools (ASATs) are instruments that support code quality assessment by automatically detecting defects and design issues. Despite their popularity, they are characterized by (i) a high false positive rate and (ii) the low comprehensibility of the generated warnings. However, no prior studies have investigated the usage of ASATs in different development contexts (e.g., code reviews, regular development), nor how open source projects integrate ASATs into their workflows. These perspectives are paramount to improve the prioritization of the identified warnings. To shed light on the actual ASATs usage practices, in this paper we first survey 56 developers (66% from industry and 34% from open source projects) and interview 11 industrial experts leveraging ASATs in their workflow with the aim of understanding how they use ASATs in different contexts. Furthermore, to investigate how ASATs are being used in the workflows of open source projects, we manually inspect the contribution guidelines of 176 open-source systems and extract the ASATs’ configuration and build files from their corresponding GitHub repositories. Our study highlights that (i) 71% of developers do pay attention to different warning categories depending on the development context; (ii) 63% of our respondents rely on specific factors (e.g., team policies and composition) when prioritizing warnings to fix during their programming; and (iii) 66% of the projects define how to use specific ASATs, but only 37% enforce their usage for new contributions. The perceived relevance of ASATs varies between different projects and domains, which is a sign that ASATs use is still not a common practice. In conclusion, this study confirms previous findings on the unwillingness of developers to configure ASATs and it emphasizes the necessity to improve existing strategies for the selection and prioritization of ASATs warnings that are shown to developers
Phenolic bisabolanes from the sponge-derived fungus Aspergillus sp.
No full textTwo new phenolic bisabolane sesquiterpenes, asperchondols A (1) and B (2), together with seven known analogues (3-9) and four known diphenyl ethers (10-13) were obtained from Aspergillus sp., that had been isolated from the marine sponge Chondrilla nucula. Their structures were elucidated through NMR and MS analysis, and by comparison with literature data. All isolated compounds were evaluated for their antibacterial activity against eight human pathogenic bacteria. Co-cultivation experiment of Aspergillus sp. with Bacillus subtilis was also conducted. (C) 2016 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.Manchot Foundation; BMBF; TubitakSCI(E)[email protected]; [email protected]
New C-methylated flavonoids and alpha-pyrone derivative from roots of Talinum triangulare growing in Nigeria
No full textThe first chemical examination of roots of the traditionally used medicinal plant Talinum triangulare (Portulacaceae) from Nigeria led to the isolation of two new C-methylated flavonoids, 5,6-dimethoxy-7-hydroxy-8-methyl-flavone (1), 5,6-dimethoxy-8-methyl-2-phenyl-7H-1-benzopyran-7-one (2), and one new a-pyrone derivative, 4-methoxy-6-(2-hydroxy-4-phenylbutyl)-2H-pyran-2-one (3), along with thirteen known compounds, including nine amides (4-12), indole-3-carboxylic acid (13), p-hydroxy benzoic acid (14), and two steroids (15-16). Their structures were elucidated by extensive spectroscopic measurements including 1D, 2D NMR, MS, and by comparison with the literature. All isolated compounds were screened for their cytotoxic and antifungal activities. However, none of them showed significant activity. (C) 2016 Elsevier B.V. All rights reserved.Society for Medicinal Plant and Natural Product Research (GA)SCI(E)[email protected]; [email protected]
The Politics of Legislative Debates
No full textThe contribution of this chapter to our volume is fourfold. First, we look at why we should study legislative debates and how scholars may benefit from representation, legislative politics, party politics, and electoral studies by incorporating debates in their analysis. In so doing, we unpack their functions in liberal democracies. Second, the chapter offers a state of the art of the burgeoning field of legislative debates. We focus on the normative scholarly discussion about legislative debates and their importance for deliberation and democratic outputs. In addition, we dwell on Proksch and Slapin's model as a watershed in the empirical study of legislative debates, particularly due to its capacity to travel and its usefulness in understanding how different institutional settings have an impact of speechmaking. Third, the chapter presents the theoretical framework, the key hypotheses guiding the volume, and our empirical approach to legislative debates. Fourth, the chapter concludes with the plan of the book
Metabolites from the Fungal Endophyte Aspergillus austroafricanus in Axenic Culture and in Fungal-Bacterial Mixed Cultures
No full textThe endophytic fungus Aspergillus austroafricanus isolated from leaves of the aquatic plant Eichhornia crassipes was fermented axenically on solid rice medium as well as in mixed cultures with Bacillus subtilis or with Streptomyces lividans. Chromatographic analysis of EtOAc extract of axenic cultures afforded two new metabolites, namely, the xanthone dimer austradixanthone (1) and the sesquiterpene (+)-austrosene (2), along with five known compounds (3-7). Austradixanthone (1) represents the first highly oxygenated heterodimeric xanthone derivative. When A. austroafricanus was grown in mixed cultures with B. subtilis or with S. lividans, several diphenyl ethers (8-11) including the new austramide (8) were induced up to 29-fold. The structures of new compounds were unambiguously elucidated using 1D- and 2D-NMR spectroscopy, HRESIMS, and chemical derivatization. Compound 7 exhibited weak cytotoxicity against the murine lymphoma L5178Y cell line (EC50 is 12.6 mu M). In addition, compounds 9 and 10, which were enhanced in mixed fungal/bacterial cultures, proved to be active against Staphylococcus aureus (ATCC 700699) with minimal inhibitory concentrations (MICs) of 25 mu M each (6.6 mu g/mL), whereas compound 11 revealed moderate antibacterial activity against B. subtilis 168 trpC2 with an MIC value of 34.8 mu M (8 mu g/mL).BMBF; Research Commission of the Medical Faculty of the Heinrich-Heine-University Dusseldorf; Federal Ministry of Education and Research (BMBF) [16GW0109]SCI(E)[email protected]; [email protected]; [email protected]
New amides from the fruits of Piper retrofractum
No full textThree new amides, (2E,14Z)-N-isobutyleicosa-2,14-dienamide (1), dipiperamides F and G (2 and 3), together with 30 known compounds were isolated from the fruits of Piper retrofractum. Their structures were elucidated by extensive spectroscopic analyses including 1D and 2D NMR as well as MS, and by comparison with the literature. A plausible biosynthetic pathway leading to the amides isolated in this study is discussed. All isolated compounds were screened for their antifungal and cytotoxic activities. Piperanine (9) showed growth inhibition against the fungus Cladosporium cladosporioides, while dipiperamides F and G (2 and 3), chabamide (30), nigramide R (31), dehydropipemonaline (24), pipernonaline (25), guineensine (22), brachystamide B (23), retrofractamide C (20), pellitorine (13), and pipericine (14) exhibited considerable cytotoxicity against L5178Y mouse lymphoma cells with IC50 values of 10.0, 13.9, 11.6, 9.3, 8.9, 17.0, 17.0, 16.4, 13.4, 28.3, and 24.2 mu M, respectively. (C) 2015 Elsevier Ltd. All rights reserved.BMBF; MOST; DIKTI (Directorate General of Higher Education Indonesia)SCI(E)[email protected]; [email protected]
Targeted solid phase fermentation of the soil dwelling fungus Gymnascella dankaliensis yields new brominated tyrosine-derived alkaloids
No full textSeven new brominated tyrosine-derived alkaloids, gymnastatins T-Y (1-6) and dankastatin D (7), together with three known likewise brominated analogues gymnastatins I-K (8-10) were isolated from the soil fungus Gymnascella dankaliensis through fermentation on solid rice medium following addition of NaBr. None of these compounds were detected when the fungus was cultured on rice that either lacked NaBr or that contained NaCl instead, indicating a remarkable plasticity of the fungal secondary metabolism. All structures were elucidated on the basis of one and two dimensional NMR spectroscopic analyses and MS data. The absolute configuration of the new gymnastatin T (1) was determined by X-ray crystallographic data. All isolated alkaloids showed potent to moderate cytotoxicity against the L5178Y mouse lymphoma cell line with IC50 values ranging from 0.078 to 14.1 mu M.China Scholarship Council; Ministry of Education of China; BMBF (project BALIPEND)SCI(E)[email protected]; [email protected]
Xanthones and sesquiterpene derivatives from a marine-derived fungus Scopulariopsis sp.
No full textTwo new xanthone derivatives, 12-dimethoxypinselin (1) and 12-O-acetyl-AGI-B4 (2), as well as two new phenolic bisabolane-type sesquiterpenes, 11,12-dihydroxysydonic acid (15) and 1-hydroxyboivinianic acid (16), together with one new alkaloid, scopulamide (21) and one new cc-pyrone derivative, scopupyrone (26), in addition to twenty-three known compounds (3-14,17-20, 22-25, 27-29) were isolated from solid rice cultures of the marine-derived fungus Scopulariopsis sp. obtained from the Red Sea hard coral Stylophora sp. All compounds were unambiguously identified through extensive NMR spectroscopic analyses, and by comparison with the literature. Marfey's reaction was performed to determine the absolute configuration of scopulamide (21) and TDDFT-ECD calculations were used to assign the configuration of AGI-B4 (3) and scopupyrone (26). All isolated compounds were evaluated for their cytotoxicity against L5178Y mouse lymphoma cells and the structure-activity relationships were discussed. (C) 2016 Elsevier Ltd. All rights reserved.Egyptian Government (Ministry of High Education); Hungarian National Research Foundation [OTKA K105871]; National Information Infrastructure Development Institute [NIIFI 10038]; Manchot FoundationSCI(E)[email protected]; [email protected]
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