540 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
Intercomparison of snow density measurements: bias, precision, and vertical resolution
No full textDensity is a fundamental property of porous media such as snow. A wide range of snow properties and physical processes are linked to density, but few studies have addressed the uncertainty in snow density measurements. No study has yet quantitatively considered the recent advances in snow measurement methods such as micro-computed tomography (uCT) in alpine snow. During the MicroSnow Davos 2014 workshop, different approaches to measure snow density were applied in a controlled laboratory environment and in the field. Overall, the agreement between uCT and gravimetric methods (density cutters) was 5 to 9 %, with a bias o
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]
Disentangling the influence of attachment anxiety and attachment security in consumer formation of attachments to brands
No full textArticle first published online: 28 JUN 2013ABSTRACTThis research investigates the formation of consumer attachments to brands contingent upon their attachment anxiety and security. An experiment utilizes a consumer sample and real brands across four product categories (apparel, body care, consumer electronics, and soft drinks) to test the relations between consumer–brand identification and brand attachment dependent on attachment anxiety and attachment security. Consistent with previous research, the findings initially confirm that consumer–brand identification relates positively to brand attachment. Prior work is extended, however, by demonstrating that attachment anxiety has a strong influence on this relationship by moderating the effect of consumer–brand identification on brand attachment but only under low attachment security and with women. Implications relate to attachment research and brand management. Copyright © 2013 John Wiley & Sons, Ltd.Michael Proksch, Ulrich R. Orth and Franziska Bethg
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]
Competence enhancement and anticipated emotion as motivational drivers of brand attachment
No full textFocusing on the motivational processes underlying consumer attachments to brands, this research examines how competence enhancement and anticipated emotion (anxiety and joy) contribute to attachment. Personal attachment style (attachment anxiety) and type of motivation (intrinsic vs. extrinsic) are included as individual differences. Employing two field studies across different contexts indicates that competence enhancement leads to stronger attachments with anticipated anxiety (avoidance) and joy (approach) mediating this relationship. Analyses of moderated mediation further show that the effect mediated through anticipated emotion is stronger under conditions of high extrinsic and low intrinsic motivation, and when individual attachment anxiety is low. Implications for brand attachment research and management are discussed. © 2015 Wiley Periodicals, Inc.Michael Proksch, Ulrich R. Orth, T. Bettina Cornwel
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]
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]
Pretrichodermamide C and N-methylpretrichodermamide B, two new cytotoxic epidithiodiketopiperazines from hyper saline lake derived Penicillium sp.
No full textTwo new epidithiodiketopiperazines, pretrichodermamide C (1) and N-methylpretrichodermamide B (2) were isolated from the fungus Penicillium sp., derived from the sediment of a hyper saline lake located at Wadi El-Natrun in Egypt. The structures of 1 and 2 were unambiguously determined on the basis of one-and two-dimensional NMR spectroscopy and by high-resolution mass spectrometry, as well as by comparison with the literature. Compound 2 showed pronounced cytotoxicity against the murine lymphoma L5178Y cell line with an IC50 value of 2 mu M. (C) 2014 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000350569100032&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Biochemistry & Molecular BiologyPlant SciencesSCI(E)[email protected]; [email protected]
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