| 1. |
- Aqueveque, Pedro, et al.
(författare)
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Antifungal activities of extracts produced by liquid fermentations of Chilean Stereum species against Botrytis cinerea (grey mould agent)
- 2016
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Ingår i: Crop Protection. - : Elsevier BV. - 0261-2194. ; 89, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- Extracts obtained from liquid mycelial fermentations of Chilean species of the Stereum genus showed antifungal activity against Botrytis cinerea. Thirty-six strains were evaluated in vivo and in vitro assays, 25 belonging to Stereum hirsutum (Sh) and 11 to Stereum rameale (Sr). Two types of extracts were obtained: EtOAc-extract (liquid phase) and MeOH-extract (mycelial phase). Plate diffusion assay showed that EtOAc-extracts were more active than MeOH-extracts. S. hirsutum included 4 strains with the highest antifungal activity (Sh134-11, Sh144-11, Sh152-11, Sh155-11) and S. rameale highlighted with two strains (Sr25-11, Sr27-11). Effects on the mycelial growth of B. cinerea showed that EtOAc-extracts produced by S. hirsutum (Sh134-11, Sh152-11) inhibited from 1000 μg mL−1, reaching 67 and 49%, respectively. At 2000 μg mL−1, these strains inhibited nearly 80% of mycelial growth. EtOAc-extract of Sh134-11 was more effective to control the sporogenesis, inhibiting in 100% the sporulation at 500 μg mL−1. Assays showed that Sh134-11 and Sh152-11 exhibited a minimal fungicidal concentration (MFC) of 50 and 100 μg mL−1 respectively and minimal inhibitory concentration (MIC) at 20 μg mL−1. EtOAc-extracts of Sr25-11 and Sr27-11 showed MFC value at 100 μg mL−1 and MIC at 20 and 50 μg mL−1, respectively. Strawberries treated with 1000 μg mL−1of Sh134-11 and Sr25-11 reached 82 and 72% of decay inhibition, respectively. Treatments with 2000 μg mL−1 showed a decay inhibition of 90% approximately. In vivo tests are in accordance with the results obtained in vitro assays, confirming the efficacy of Sh134-11 and Sr25-11 to control B. cinerea. Differences in antifungal activities observed in the different strains suggested that the ability to produce bioactive compounds is not homogenously distributed among S. hirsutum and S. rameale. Our study would suggest that submerged fermentations of Chilean S. hirsutum strain Sh134-11 produce extracts, which could be used as possible biofungicides and an alternative to synthetic fungicides.
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| 2. |
- Aqueveque, Pedro, et al.
(författare)
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Antifungal activities of secondary metabolites isolated from liquid fermentations of Stereum hirsutum (Sh134-11) against Botrytis cinerea (grey mould agent)
- 2017
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Ingår i: Food and Chemical Toxicology. - : Elsevier BV. - 0278-6915. ; 109, s. 1048-1054
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Tidskriftsartikel (refereegranskat)abstract
- Extracts obtained from liquid mycelial fermentations of the Chilean fungus Stereum hirsutum (Sh134-11) showed antifungal activity against Botrytis cinerea. Two types of extracts were obtained: EtOAc-extract (liquid phase) and MeOH-extract (mycelial phase). Plate diffusion assay showed that EtOAc-extracts were more active than MeOH-extracts. A large-scale fermentation of Sh134-11 and chromatographic methods allowed to isolated four compounds: MS-3, Vibralactone, Vibralactone B and Sterenin D. Only Sterenin D showed antifungal activity against B. cinerea in the tests performed. Effects on the mycelial growth of B. cinerea showed that Sterenin D showed inhibition at 1000-2000 μg/mL reaching 67% and 76% respectively. Sterenin D was more effective to control the sporogenesis, inhibiting in 96% the sporulation at 500 μg/mL. Assays showed that Sterenin D exhibited a minimal fungicidal concentration (MFC) of 50 μg/mL and minimal inhibitory concentration (MIC) at 20 μg/mL.Our study indicated that submerged fermentations of Chilean S. hirsutum (Sh134-11) produced extracts with antifungal activity and Sterenin D is responsible for this activity, which could be used as possible biofungicides alternative to synthetic fungicides.
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| 3. |
- Aqueveque, Pedro, et al.
(författare)
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Bioactive compounds isolated from submerged fermentations of the Chilean fungus Stereum rameale
- 2015
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Ingår i: Zeitschrift fuer Naturforschung. Section C: A Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075. ; 70:3-4, s. 97-102
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Tidskriftsartikel (refereegranskat)abstract
- Liquid fermentations of the fungus Stereum rameale (No 2511) yielded extracts with antibacterial -activity. The antibacterial activity reached its peak after 216 h of stirring. Bioassay-guided fractionation methods were employed for the isolation of the bioactive metabolites. Three known compounds were identified: MS-3 (1), vibralactone (2) and vibralactone B (3). The three compounds showed antibacterial activity as a function of their concentration. Minimal bactericidal concentrations (MBC) of compound 1 against Gram-positive bacteria were as follows: Bacillus cereus (50 mu g/mL), Bacillus subtilis (10 mu g/mL) and Staphylococcus aureus (100 mu g/mL). Compounds 2 and 3 were active only against Gram-negative bacteria. The MBC of compound 2 against Escherichia coli was 200 mu g/mL. Compound 3 inhibited significantly the growth of E. coli and Pseudomonas aeruginosa, with MBC values of 50 and 100 mu g/mL, respectively.
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| 4. |
- Cuaran, Jose, et al.
(författare)
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Lightning Attachment to UHV Power Transmission Lines : Effect of the Phase Voltage
- 2019
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Ingår i: IEEE Transactions on Power Delivery. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8977 .- 1937-4208. ; 34:2, s. 729-738
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Tidskriftsartikel (refereegranskat)abstract
- The self-consistent leader inception and propagation model is used to analyze the influence of the phase voltage on the attachment of lightning to ultra-high voltage power transmission lines (UHV-TLs). An UHV-ac line with shielding failures reported in the literature is used as a case study. It is shown that the length of upward leaders initiated fromconductors and their striking distances are longer under positive voltages than when energized with the opposite polarity. Therefore, the fraction of shielding failures of each conductor changes significantly with the phase angle in ac lines. However, it is found that the overall effect of voltage on lightning attachment can also be limited by the electrostatic screening produced by shield wires and their leaders. This proximity effect mainly reduces the velocity of upward leaders launched from energized conductors. Therefore, the effect of voltage on the lightning attachment process cannot be generalized since it is strongly coupled to the proximity of shield wires and their associated leaders. Thus, the lightning shielding performance should consider case-to-case variations in the upward leader velocity in different UHV-TLs designs, given not only by the line voltage but also coupled to the proximity of other wires and their launched leaders.
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| 5. |
- Cuaran, Jose, et al.
(författare)
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Lightning Shielding Analysis of EHV and UHV Transmission Lines : On the Effect of Terrain Topography
- 2016
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Ingår i: 2016 33RD INTERNATIONAL CONFERENCE ON LIGHTNING PROTECTION (ICLP). - : IEEE. - 9781509058433
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Konferensbidrag (refereegranskat)abstract
- In this paper, the Self-Consisting Leader Inception and Propagation Model -SLIM- is used to analyze the shielding performance of transmission lines, with special attention on the terrain topography effect. Transverse and Longitudinal terrain profiles are considered. It is found that a transmission line can be more vulnerable to be struck by lightning on any terrain that leads to increase the height of the conductors. In addition, the striking distance to the phase conductors strongly depends on the landform and the tower geometry, which suggests changes in the current lightning protection standards.
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| 6. |
- Stray-Pedersen, Asbjorg, et al.
(författare)
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Primary immunodeficiency diseases : Genomic approaches delineate heterogeneous Mendelian disorders
- 2017
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Ingår i: Journal of Allergy and Clinical Immunology. - : MOSBY-ELSEVIER. - 0091-6749 .- 1097-6825. ; 139:1, s. 232-245
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Tidskriftsartikel (refereegranskat)abstract
- Background: Primary immunodeficiency diseases (PIDDs) are clinically and genetically heterogeneous disorders thus far associated with mutations in more than 300 genes. The clinical phenotypes derived from distinct genotypes can overlap. Genetic etiology can be a prognostic indicator of disease severity and can influence treatment decisions. Objective: We sought to investigate the ability of whole-exome screening methods to detect disease-causing variants in patients with PIDDs. Methods: Patients with PIDDs from 278 families from 22 countries were investigated by using whole-exome sequencing. Computational copy number variant (CNV) prediction pipelines and an exome-tiling chromosomal microarray were also applied to identify intragenic CNVs. Analytic approaches initially focused on 475 known or candidate PIDD genes but were nonexclusive and further tailored based on clinical data, family history, and immunophenotyping. Results: A likely molecular diagnosis was achieved in 110 (40%) unrelated probands. Clinical diagnosis was revised in about half (60/ 110) and management was directly altered in nearly a quarter (26/ 110) of families based on molecular findings. Twelve PIDD-causing CNVs were detected, including 7 smaller than 30 Kb that would not have been detected with conventional diagnostic CNV arrays. Conclusion: This high-throughput genomic approach enabled detection of disease-related variants in unexpected genes; permitted detection of low-grade constitutional, somatic, and revertant mosaicism; and provided evidence of a mutational burden in mixed PIDD immunophenotypes.
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