| 1. |
- Amadori, Kristian, et al.
(författare)
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Multidisciplinary Optimization of Wing Structure Using Parametric Models
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aircraft design is an inherently multidisciplinary activity that requires integrating different models and tools to reach a well-balanced and optimized product. At Linköping University a design framework is being developed to support the initial design space exploration and the conceptual design phase. Main characteristics of the framework are its flexible database in XML format, together with close integration of automated CAD and other tools, which allows the developed geometry to be directly used in the subsequent preliminary design phase. In particular, the aim of the proposed work is to test the framework by designing, optimizing and studying a transport aircraft wing with respect to aerodynamic, geometry, structural and accessability constraints. The project will provide an initial assessment of the capability of the framework, both in terms of processing speed and accuracy of the results.
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| 2. |
- Bergentall, Martina, et al.
(författare)
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Malolactic fermentation in lingonberry juice and its use as a preservative
- 2024
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Ingår i: Food microbiology (Print). - 0740-0020 .- 1095-9998. ; 121
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Tidskriftsartikel (refereegranskat)abstract
- Lingonberry is a common wild berry that is often sold as jams and beverages. It naturally contains high amounts of the weak acid preservative benzoic acid making it an interesting ingredient for shelf-life extension. Despite this, their use as a raw ingredient is limited by the inherently intense sour taste. This study aimed to improve the taste of lingonberry juice by subjecting it to malolactic fermentation in order to reduce the sourness, and to investigate the benzoic acid in lingonberries as a natural preservative in juice blends by determining the microbial stability. After initial screening of lactic acid bacteria, a Lactiplantibacillus plantarum strain was used as the starter for subsequent investigations. Upon raising the pH, all malic acid was completely converted to lactic acid after seven days. The fermented juice was mixed with blackcurrant juice in different proportions. Challenge tests of the blends showed Listeria monocytogenes could not grow in any juice samples, while Candida albicans only grew in the pure blackcurrant juice. Aspergillus brasiliensis growth was delayed in all samples containing benzoic acid in a concentration-dependent manner. The sourness and astringency were substantially reduced in the juice with added L. plantarum compared to the unfermented juice. © 2024 The Authors
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| 3. |
- Bergentall, Martina, et al.
(författare)
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Reduction of malic acid in bilberry juice by Lactiplantibacillus plantarum-mediated malolactic fermentation
- 2024
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Ingår i: European Food Research and Technology. - : Springer Science and Business Media Deutschland GmbH. - 1438-2377 .- 1438-2385. ; 250:3, s. 811-
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Tidskriftsartikel (refereegranskat)abstract
- Bilberries (Vaccinium myrtillus) are the most common wild berries in Northern Europe. A substantial amount of the berries are picked with the objective to extract highly valued products such as anthocyanins. A smaller amount of the bilberries is used to make jams and drinks, and these are generally restricted to the domestic market. One reason is the sour taste, partly as a result of the high content of malic acid. By using certain strains of lactic acid bacteria with the ability to convert malic acid to lactic acid, the taste is predicted to be more pleasant. This process is called malolactic fermentation, and historically it has mostly been used in winemaking. After testing five different starter cultures, we identified that the strain, Lactiplantibacillus plantarum LP58, can rapidly convert malic acid to lactic acid without any loss of sugar or citric acid, which strongly indicates a successful malolactic acid fermentation. As it has been reported that other strains of L. plantarum can be used as biopreservative agents, the resulting product was also tested in terms of microbial safety after prolonged storage, and by means of metagenome sequencing. The obtained product was quite tolerant to microbial growth, but this observation was rather due to an initial heat treatment than the addition of lactobacilli. Potentially, starter cultures with documented biopreservative activity can be combined with L. plantarum LP58 to obtain a more stable product. Until then, the fermented bilberry juice must be processed and preserved like non-fermented bilberry products. © 2023, The Author(s).
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| 4. |
- de Vries, Ronald P, et al.
(författare)
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Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus
- 2017
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus.ResultsWe have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli.ConclusionsMany aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
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| 5. |
- Fredlund, Elisabeth, et al.
(författare)
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Oxygen and carbon source-regulated expression of PDC and ADH genes in the respiratory yeast Pichia anomala
- 2006
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Ingår i: Yeast. - West Sussex, USA : John Wiley & Sons. - 0749-503X .- 1097-0061. ; 23:16, s. 1137-1149
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Tidskriftsartikel (refereegranskat)abstract
- We amplified, sequenced and studied the transcriptional regulation of genes of the alcoholic fermentation pathway in the biocontrol and non-Saccharomyces wine yeast, Pichia anomala. Two ADH isogenes, PaADH1 and PaADH2, and one PDC gene, PaPDC1, were amplified from genomic P. anomala DNA by a two-step PCR approach, using degenerated primers against conserved regions of the respective genes for cloning core regions, and PCR-based gene walking for cloning the respective 5' and 3'-ends. According to sequence analysis, ADHI and PDC1 are most likely cytoplasmatic proteins, while ADH2 is most probably localized in the mitochondria. PaADH1 was expressed during aerobic growth on glucose, ethanol and succinate, but was ninefold upregulated in response to oxygen limitation when grown on glucose. The gene seems to be involved in both production and consumption of ethanol. Only low expression of PaADH2 was detected during growth on glucose and ethanol, but it was highly expressed during growth on the non-fermentable carbon source succinate and repressed by the addition of glucose. PaPDC1 was expressed during aerobic growth on glucose and was upregulated four-fold in response to oxygen limitation. PaPDC1 expression was lower in cells grown on ethanol and succinate than on glucose and was up- regulated two- and four-fold, respectively, after glucose addition. Our results demonstrate that transcription of genes of the fermentative pathway is regulated by hypoxia and carbon source but posttranscriptional regulation may play a major role in regulating the metabolic flux.
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| 6. |
- Ihrmark, Katarina, et al.
(författare)
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Comparative Molecular Evolution of Trichoderma Chitinases in Response to Mycoparasitic Interactions
- 2010
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Ingår i: Evolutionary Bioinformatics. - 1176-9343. ; 6, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Certain species of the fungal genus Trichoderma are potent mycoparasites and are used for biological control of fungal diseases on agricultural crops. In Trichoderma, whole-genome sequencing reveal between 20 and 36 different genes encoding chitinases, hydrolytic enzymes that are involved in the mycoparasitic attack. Sequences of Trichoderma chitinase genes chi18-5, chi18-13, chi18-15 and chi18-17, which all exhibit specific expression during mycoparasitism-related conditions, were determined from up to 13 different taxa and studied with regard to their evolutionary patterns. Two of them, chi18-13 and chi18-17, are members of the B1/B2 chitinase subgroup that have expanded significantly in paralog number in mycoparasitic Hypocrea atroviridis and H. virens. Chi18-13 contains two codons that evolve under positive selection and seven groups of co-evolving sites. Chi18-15 displays a unique codon-usage and contains five codons that evolve under positive selection and three groups of co-evolving sites. Regions of high amino acid variability are preferentially localized to substrate-or product side of the catalytic clefts. Differences in amino acid diversity/conservation patterns between different Trichoderma clades are observed. These observations show that Trichoderma chitinases chi18-13 and chi18-15 evolve in a manner consistent with rapid co-evolutionary interactions and identifies putative target regions involved in determining substrate-specificity.
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| 7. |
- Johnsson, Anna-Ida, et al.
(författare)
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Development and evaluation of SCAR markers for a Pseudomonas brassicacearum strain used in biological control of snow mould
- 2009
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Ingår i: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 48, s. 181-187
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Tidskriftsartikel (refereegranskat)abstract
- Biological control microorganisms have long been promoted as an alternative to conventional pesticides. Before registration of a microbial biocontrol product for commercial sale, it must be evaluated as regards potential spread and persistence after release. In this study, strainspecific sequence-characterized amplified region (SCAR) markers were developed to monitor the biocontrol candidate strain Pseudomonas brassicacearum MA250, which is effective against snow mould (Microdochium nivale). One SCAR marker, OPA2-73, was used in quantitative real-time PCR (Q-PCR) on samples from a climate chamber experiment in which winter wheat seeds were treated with the bacterium or a chemical control agent, or left untreated. The results showed that MA250 persisted for up to 3 weeks after sowing on the kernel residues and also colonized the roots of treated seedlings. Total MA250 cell numbers on biocontrol treated seedlings after three weeks were approximately 10(6) Cells, compared with the original inoculum of 10(6)-10(7) cells per seed. Corresponding cell numbers of MA250 on chemically treated and untreated seedlings were below the detection limit. This study shows that SCAR marker OPA2-73 is a specific and sensitive tool for monitoring the biocontrol microorganism MA250 in environmental samples. (C) 2008 Elsevier Inc. All rights reserved.
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| 8. |
- Johnsson, Anna-Ida, et al.
(författare)
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Fate and behaviour of a seed-applied Pseudomonas brassicacearum strain in a winter wheat field trial, as determined by analysis with SCAR markers
- 2012
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Ingår i: Biocontrol Science and Technology. - : Informa UK Limited. - 0958-3157 .- 1360-0478. ; 22, s. 379-392
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Tidskriftsartikel (refereegranskat)abstract
- The fate and behaviour of the seed-applied biocontrol strain Pseudomonas brassicacearum MA250 in a field trial with winter wheat was determined using sequence-characterised amplified region (SCAR) markers. Samples of below-ground plant parts from healthy and withered (due to snow mould infection) seedlings were collected approximately one and seven months after sowing, which was performed in early autumn. DNA was extracted from roots and remaining parts of seeds with adhering soil, and the abundance of the strain was determined in quantitative real-time PCR (qPCR) assays. The results show that the introduced strain persisted over the whole trial-period of seven months. On termination of the trial (after seven months) the below-ground plant parts of each plant housed 10(6)-10(7) cells, substantially less than the original approximately 10 9 cells inoculated onto the seed. In healthy seedlings, there was a shift in cell numbers from seeds to roots between the samplings, suggesting colonisation of the roots during this time. The results show that with sufficient attention given to analytical control measures and the possibility of resident background populations, SCAR markers in combination with qPCR provide valuable information regarding the fate and behaviour of biocontrol micro-organisms under field conditions.
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| 9. |
- Johnsson, Anna-Ida, et al.
(författare)
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Specific SCAR markers and multiplex real-time PCR for quantification of two Trichoderma biocontrol strains in environmental samples
- 2011
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Ingår i: BioControl. - : Springer Science and Business Media LLC. - 1386-6141 .- 1573-8248. ; 56, s. 903-913
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Tidskriftsartikel (refereegranskat)abstract
- Several strains from the genus Trichoderma (Ascomycetes, Hypocreales) are commercially used as biocontrol agents, e.g. in formulations containing the two Trichoderma strains IMI206039 (Hypocrea parapilulifera B.S. Lu, Druzhinina & Samuels) and IMI206040 (T. atroviride P. Karst). To quantify the presence of the two isolates after application, we developed primers for SCAR markers (Sequence-Characterised Amplified Region). In order to quantify both fungal strains simultaneously, we also designed fluorophore-labelled probes distinguishing the two strains, to be used in combination with the SCAR primers. In incubations of two different soils, artificially inoculated and maintained under controlled conditions, the quantification through amplification with the SCAR markers in qPCR and through colony-forming units from plate counting correlated well. Further tests of the markers on samples taken from a golf green treated with a product containing both strains indicated that the two biocontrol strains did not establish, either on the golf green or in the surrounding area.
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| 10. |
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