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  • 1
    Electronic Resource
    Electronic Resource
    An extended x-ray absorption fine structure study by employing molecular dynamics simulations: Bromide ion in methanolic solution (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 1779-1790 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: X-ray absorption spectroscopy is widely employed in the structural analysis of disordered systems. In the standard extended x-ray absorption fine structure (EXAFS) analysis the coordination of the photoabsorber is usually defined by means of Gaussian shells. It is known that this procedure can lead to significant errors in the determination of the coordination parameters for systems which present anharmonic thermal vibrations or interatomic asymmetric pair distribution functions. An efficient method has been recently employed in the study of the hydration shells of bromide and rubidium ions and brominated hydrocarbon molecules in diluted aqueous solutions. According to this method, pair distribution functions [g(r)] obtained from molecular dynamics simulations can be used as relevant models in the calculation of the EXAFS signals. Moreover, asymmetric shells modeled on the g(r) first peaks, have been employed in the EXAFS analysis and the parameters defining the asymmetric peaks have been optimized during the minimization procedure. In the present paper this new procedure has been used to investigate the coordination of Br− in methanol. The analysis of this system is particularly interesting due to the presence of three well separated coordination shells. We show that the inclusion of the hydrogen signal is essential to perform a reliable analysis. A comparison of the analysis with asymmetric and Gaussian shells shows how the accuracy of the EXAFS data analysis is improved by using asymmetric shells. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471711
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Agriculture, Vol. 9, Pages 231: Experimental Study to Support Local Sunflower Oil Chains: Production of Cold Pressed Oil in Central Italy (2019)
    MDPI
    Details
    Publication Date: 2019
    Description: Sunflower is one of the most important oilseed crops cultivated in the world for different purposes. In Italy, the production is mostly located in the central area, representing 70% of Italian production. The market demand for sunflower oil is higher than the national production. There is an increasing request for cold pressed sunflower oil for food application. The success of this activity is linked to a correct setting up and management of the production and supply chain with a valorization of products and by-products. To this aim, information is needed, and this paper is focused on the cultivation of sunflower in central Italy using suitable hybrids, as well as on the study of the cold extraction performance of the sunflower seed produced and the quality of by-products and residues. Results indicate that, on average, a range of about 1.0–1.5 t ha−1 of cold pressed oil and different amounts of by-products can be obtained. According to a proposed scenario, 30 ha cultivated with sunflower are needed to create a complete supply chain within the farm, avoiding many additional passages and maintaining all the value for the farmer. It is important to use suitable hybrids for obtaining good yield, but also the cold extraction performances are important because they also affect the quality of by-products and residues that can be valorized themselves to improve sustainability.
    Electronic ISSN: 2077-0472
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by MDPI
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    PAPER CURRENT
  • 3
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    Pyrenosetin D, a New Pentacyclic Decalinoyltetramic Acid Derivative from the Algicolous Fungus Pyrenochaetopsis sp. FVE-087 (2020)
    MDPI
    Details
    Publication Date: 2023-02-08
    Description: The fungal genus Pyrenochaetopsis is commonly found in soil, terrestrial, and marine environments, however, has received little attention as a source of bioactive secondary metabolites so far. In a recent work, we reported the isolation and characterization of three new anticancer decalinoyltetramic acid derivatives, pyrenosetins A-C, from the Baltic Fucus vesiculosus-derived endophytic fungus Pyrenochaetopsis sp. FVE-001. Herein we report a new pentacyclic decalinoylspirotetramic acid derivative, pyrenosetin D (1), along with two known decalin derivatives wakodecalines A (2) and B (3) from another endophytic strain Pyrenochaetopsis FVE-087 isolated from the same seaweed and showed anticancer activity in initial screenings. The chemical structures of the purified compounds were elucidated by comprehensive analysis of HR-ESIMS, FT-IR, [a]D, 1D and 2D NMR data coupled with DFT calculations of NMR parameters and optical rotation. Compounds 1-3 were evaluated for their anticancer and toxic potentials against the human malignant melanoma cell line (A-375) and the non-cancerous keratinocyte cell line (HaCaT). Pyrenosetin D (1) showed toxicity towards both A-375 and HaCaT cells with IC50 values of 77.5 and 39.3 μM, respectively, while 2 and 3 were inactive. This is the third chemical study performed on the fungal genus Pyrenochaetopsis and the first report of a pentacyclic decalin ring system from the fungal genus Pyrenochaetopsis.
    Type: Article , PeerReviewed
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  • 4
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    Application of Feature-Based Molecular Networking for Comparative Metabolomics and Targeted Isolation of Stereoisomers from Algicolous Fungi (2022)
    MDPI
    Details
    Publication Date: 2024-02-07
    Description: Seaweed endophytic (algicolous) fungi are talented producers of bioactive natural products. We have previously isolated two strains of the endophytic fungus, Pyrenochaetopsis sp. FVE-001 and FVE-087, from the thalli of the brown alga Fucus vesiculosus. Initial chemical studies yielded four new decalinoylspirotetramic acid derivatives with antimelanoma activity, namely pyrenosetins A–C (1–3) from Pyrenochaetopsis sp. strain FVE-001, and pyrenosetin D (4) from strain FVE-087. In this study, we applied a comparative metabolomics study employing HRMS/MS based feature-based molecular networking (FB MN) on both Pyrenochaetopsis strains. A higher chemical capacity in production of decalin derivatives was observed in Pyrenochaetopsis sp. FVE-087. Notably, several decalins showed different retention times despite the same MS data and MS/MS fragmentation pattern with the previously isolated pyrenosetins, indicating they may be their stereoisomers. FB MN-based targeted isolation studies coupled with antimelanoma activity testing on the strain FVE-087 afforded two new stereoisomers, pyrenosetins E (5) and F (6). Extensive NMR spectroscopy including DFT computational studies, HR-ESIMS, and Mosher’s ester method were used in the structure elucidation of compounds 5 and 6. The 3′R,5′R stereochemistry determined for compound 6 was identical to that previously reported for pyrenosetin C (3), whose stereochemistry was revised as 3′S,5′R in this study. Pyrenosetin E (5) inhibited the growth of human malignant melanoma cells (A-375) with an IC50 value of 40.9 μM, while 6 was inactive. This study points out significant variations in the chemical repertoire of two closely related fungal strains and the versatility of FB MN in identification and targeted isolation of stereoisomers. It also confirms that the little-known fungal genus Pyrenochaetopsis is a prolific source of complex decalinoylspirotetramic acid derivatives.
    Type: Article , PeerReviewed
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  • 5
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    Induction of Isochromanones by Co-Cultivation of the Marine Fungus Cosmospora sp. and the Phytopathogen Magnaporthe oryzae (2022)
    MDPI
    Details
    Publication Date: 2024-02-07
    Description: Microbial co-cultivation is a promising approach for the activation of biosynthetic gene clusters (BGCs) that remain transcriptionally silent under artificial culture conditions. As part of our project aiming at the discovery of marine-derived fungal agrochemicals, we previously used four phytopathogens as model competitors in the co-cultivation of 21 marine fungal strains. Based on comparative untargeted metabolomics analyses and anti-phytopathogenic activities of the co-cultures, we selected the co-culture of marine Cosmospora sp. with the phytopathogen Magnaporthe oryzae for in-depth chemical studies. UPLC-MS/MS-based molecular networking (MN) of the co-culture extract revealed an enhanced diversity of compounds in several molecular families, including isochromanones, specifically induced in the co-culture. Large scale co-cultivation of Cosmospora sp. and M. oryzae resulted in the isolation of five isochromanones from the whole co-culture extract, namely the known soudanones A, E, D (1-3) and their two new derivatives, soudanones H-I (4-5), the known isochromans, pseudoanguillosporins A and B (6, 7), naphtho-γ-pyrones, cephalochromin and ustilaginoidin G (8, 9), and ergosterol (10). Their structures were established by NMR, HR-ESIMS, FT-IR, electronic circular dichroism (ECD) spectroscopy, polarimetry ([α]D), and Mosher’s ester reaction. Bioactivity assays revealed antimicrobial activity of compounds 2 and 3 against the phytopathogens M. oryzae and Phytophthora infestans, while pseudoanguillosporin A (6) showed the broadest and strongest anti-phytopathogenic activity against Pseudomonas syringae, Xanthomonas campestris, M. oryzae and P. infestans. This is the first study assessing the anti-phytopathogenic activities of soudanones.
    Type: Article , PeerReviewed
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  • 6
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    Enhanced Molecular Networking Shows Microbacterium sp. V1 as a Factory of Antioxidant Proline-Rich Peptides (2023)
    MDPI
    Details
    Publication Date: 2024-02-07
    Description: Two linear proline-rich peptides (1–2), bearing an N-terminal pyroglutamate, were isolated from the marine bacterium Microbacterium sp. V1, associated with the marine sponge Petrosia ficiformis, collected in the volcanic CO2 vents in Ischia Island (South Italy). Peptide production was triggered at low temperature following the one strain many compounds (OSMAC) method. Both peptides were detected together with other peptides (3–8) via an integrated, untargeted MS/MS-based molecular networking and cheminformatic approach. The planar structure of the peptides was determined by extensive 1D and 2D NMR and HR-MS analysis, and the stereochemistry of the aminoacyl residues was inferred by Marfey’s analysis. Peptides 1–8 are likely to arise from Microbacterium V1 tailor-made proteolysis of tryptone. Peptides 1 and 2 were shown to display antioxidant properties in the ferric-reducing antioxidant power (FRAP) assay.
    Type: Article , PeerReviewed
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  • 7
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    Density Functional Theory (DFT)-Aided Structure Elucidation of Linear Diterpenes from the Irish Brown Seaweed Bifurcaria bifurcata (2021)
    MDPI
    Details
    Publication Date: 2024-02-07
    Description: Brown alga Bifurcaria bifurcata is an extraordinarily rich source of linear (acylic) diterpenes with enormous structural diversity. As part of our interest into secondary metabolites of the Irish seaweeds, here we report four new acyclic diterpenes (1–4) and seven known terpenoids (5–11) from the CHCl3 extract B. bifurcata. The planar structures of the new metabolites were elucidated by means of 1D and 2D NMR, HRMS, and FT-IR spectroscopy. Since linear diterpenes are highly flexible compounds, the assignment of their stereochemistry by conventional methods, e.g., NOESY NMR, is difficult. Therefore, we employed extensive quantum-mechanical prediction of NMR chemical shifts and optical rotation analyses to identify the relative and absolute configurations of the new compounds 1–4. Several compounds moderately inhibited the human breast cancer cell line (MDA-MB-231) with IC50 values ranging from 10.0 to 33.5 μg/mL. This study not only demonstrates the vast capacity of the Irish B. bifurcata to produce highly oxygenated linear diterpenoids, but also highlights the potential of new methodologies for assignment of their stereogenic centers
    Type: Article , PeerReviewed
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  • 8
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    Bioactivity and Metabolome Mining of Deep-Sea Sediment-Derived Microorganisms Reveal New Hybrid PKS-NRPS Macrolactone from Aspergillus versicolor PS108-62 (2023)
    MDPI
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    Publication Date: 2024-02-07
    Description: Despite low temperatures, poor nutrient levels and high pressure, microorganisms thrive in deep-sea environments of polar regions. The adaptability to such extreme environments renders deep-sea microorganisms an encouraging source of novel, bioactive secondary metabolites. In this study, we isolated 77 microorganisms collected by a remotely operated vehicle from the seafloor in the Fram Strait, Arctic Ocean (depth of 2454 m). Thirty-two bacteria and six fungal strains that represented the phylogenetic diversity of the isolates were cultured using an One-Strain-Many-Compounds (OSMAC) approach. The crude EtOAc extracts were tested for antimicrobial and anticancer activities. While antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium was common for many isolates, only two bacteria displayed anticancer activity, and two fungi inhibited the pathogenic yeast Candida albicans. Due to bioactivity against C. albicans and rich chemical diversity based on molecular network-based untargeted metabolomics, Aspergillus versicolor PS108-62 was selected for an in-depth chemical investigation. A chemical work-up of the SPE-fractions of its dichloromethane subextract led to the isolation of a new PKS-NRPS hybrid macrolactone, versicolide A (1), a new quinazoline (−)-isoversicomide A (3), as well as three known compounds, burnettramic acid A (2), cyclopenol (4) and cyclopenin (5). Their structures were elucidated by a combination of HRMS, NMR, [α]D, FT-IR spectroscopy and computational approaches. Due to the low amounts obtained, only compounds 2 and 4 could be tested for bioactivity, with 2 inhibiting the growth of C. albicans (IC50 7.2 µg/mL). These findings highlight, on the one hand, the vast potential of the genus Aspergillus to produce novel chemistry, particularly from underexplored ecological niches such as the Arctic deep sea, and on the other, the importance of untargeted metabolomics for selection of marine extracts for downstream chemical investigations.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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    Format: archive
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