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- Andersson, Martin, et al.
(författare)
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- 2009
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Patel, Alok, Dr. 1989-, et al.
(författare)
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Simultaneous production of DHA and squalene from Aurantiochytrium sp. grown on forest biomass hydrolysates
- 2019
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Ingår i: Biotechnology for Biofuels. - : BioMed Central. - 1754-6834. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundRecent evidence points to the nutritional importance of docosahexaenoic acid (DHA) in the human diet. Thraustochytrids are heterotrophic marine oleaginous microorganisms capable of synthesizing high amounts of DHA, as well as other nutraceutical compounds such as squalene, in their cellular compartment. Squalene is a natural triterpene and an important biosynthetic precursor to all human steroids. It has a wide range of applications in the cosmetic and pharmaceutical industries, with benefits that include boosting immunity and antioxidant activity. Apart from its nutritional quality, it can also be utilized for high-grade bio-jet fuel by catalytic conversion.ResultsIn the present study, the potential of thraustochytrid strain Aurantiochytrium sp. T66 to produce DHA and squalene was evaluated. When the strain was cultivated on organosolv-pretreated birch hydrolysate (30 g/L glucose) in flask, it resulted in 10.39 g/L of cell dry weight and 4.98 g/L of total lipids, of which 25.98% was DHA. In contrast, when the strain was grown in a bioreactor, cell dry weight, total lipid, and DHA increased to 11.24 g/L, 5.90 g/L, and 35.76%, respectively. The maximum squalene yield was 69.31 mg/gCDW (0.72 g/L) when the strain was cultivated in flask, but it increased to 88.47 mg/gCDW (1.0 g/L), when cultivation shifted to a bioreactor.ConclusionsThis is the first report demonstrating the utilization of low cost non-edible lignocellulosic feedstock to cultivate the marine oleaginous microorganism Aurantiochytrium sp. for the production of nutraceutical vital compounds. Owing to the simultaneous generation of DHA and squalene, the strain is suitable for industrial-scale production of nutraceuticals.
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| 5. |
- Altarabichi, Mohammed Ghaith, 1981-, et al.
(författare)
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Fast Genetic Algorithm For Feature Selection — A Qualitative Approximation Approach
- 2023
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Ingår i: Evolutionary Computation Conference Companion (GECCO ’23 Companion), July 15–19, 2023, Lisbon, Portugal. - New York, NY : Association for Computing Machinery (ACM). - 9798400701207 ; , s. 11-12
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Konferensbidrag (refereegranskat)abstract
- We propose a two-stage surrogate-assisted evolutionary approach to address the computational issues arising from using Genetic Algorithm (GA) for feature selection in a wrapper setting for large datasets. The proposed approach involves constructing a lightweight qualitative meta-model by sub-sampling data instances and then using this meta-model to carry out the feature selection task. We define "Approximation Usefulness" to capture the necessary conditions that allow the meta-model to lead the evolutionary computations to the correct maximum of the fitness function. Based on our procedure we create CHCQX a Qualitative approXimations variant of the GA-based algorithm CHC (Cross generational elitist selection, Heterogeneous recombination and Cataclysmic mutation). We show that CHCQX converges faster to feature subset solutions of significantly higher accuracy, particularly for large datasets with over 100K instances. We also demonstrate the applicability of our approach to Swarm Intelligence (SI), with results of PSOQX, a qualitative approximation adaptation of the Particle Swarm Optimization (PSO) method. A GitHub repository with the complete implementation is available2. This paper for the Hot-off-the-Press track at GECCO 2023 summarizes the original work published at [3].References[1] Mohammed Ghaith Altarabichi, Yuantao Fan, Sepideh Pashami, Peyman Sheikholharam Mashhadi, and Sławomir Nowaczyk. 2021. Extracting invariant features for predicting state of health of batteries in hybrid energy buses. In 2021 ieee 8th international conference on data science and advanced analytics (dsaa). IEEE, 1–6.[2] Mohammed Ghaith Altarabichi, Sławomir Nowaczyk, Sepideh Pashami, and Peyman Sheikholharam Mashhadi. 2021. Surrogate-assisted genetic algorithm for wrapper feature selection. In 2021 IEEE Congress on Evolutionary Computation (CEC). IEEE, 776–785.[3] Mohammed Ghaith Altarabichi, Sławomir Nowaczyk, Sepideh Pashami, and Peyman Sheikholharam Mashhadi. 2023. Fast Genetic Algorithm for feature selection—A qualitative approximation approach. Expert systems with applications 211 (2023), 118528.© 2023 Copyright held by the owner/author(s).
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| 6. |
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| 7. |
- Noble, Bill, et al.
(författare)
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What do you mean by negotiation? Annotating social media discussions about word meaning
- 2021
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Ingår i: Proceedings of the 25th Workshop on the Semantics and Pragmatics of Dialogue, September 20–22, 2021, Potsdam / The Internet. - Potsdam : SemDial. - 2308-2275.
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Konferensbidrag (refereegranskat)abstract
- We present a formalisation and annotation protocol for word meaning negotiation (WMN), a conversational routine in which speakers explicitly discuss the meaning of a word or phrase. WMN is formalised as an interaction game with a shared game board and rules for subsequent contributions, as well as a semantic update function based on the state of the game board. We develop an annotation schema based on this formalisation and present the
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| 8. |
- Huch, Susanne, 1981-
(författare)
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Spatial control of mRNA stability in yeast
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The degradation of mRNA is an important modulator of gene expression and the ultimate fate of messenger mRNA. Important steps in the degradation of mRNA include initial shortening of its poly(A) tail followed by the subsequent removal of the m7G cap. These two processes are linked temporally as well as spatially. In addition to physical interactions between proteins involved in these two processes, deadenylation and decapping enzymes and accessory factors are found in P bodies. P bodies are aggregates of protein and mRNA that are induced upon stress in all eukaryotes examined. In this thesis, I examine the spatial localization of decapping factors and explore the role of P bodies in mRNA turnover in the yeast Saccharomyces cerevisiae. This thesis is based on three underlying principles. First, mRNA decapping factors are membrane associated. More so, we show that decapping factors can be co-localized with the endoplasmic reticulum and Golgi apparatus. Second, although P bodies were proposed as sites of mRNA decay, we found that they stabilize mRNA. We examined the role of P bodies in mRNA turnover using a mutant defective in their assembly, edc3∆ lsm4∆C. This strain is mutated in two decapping activators. It combines a deletion of the gene encoding the Edc3 protein and lacks the prion-like domain of Lsm4. Using the edc3∆ lsm4∆C mutant, we demonstrate that mRNA stability is significantly reduced in the absence of P bodies for longer-lived mRNA. The effect of mRNA destabilization was due to increased deadenylation and decapping dependence. Finally, the decapping factor usually found in the cytoplasm, but accumulates in the nucleus in the P body deficient strain (edc3∆ lsm4∆C). This implies a possible role in modulating transcription.A model for the functioning of P bodies that is consistent with our work is that P bodies serve a role as a cytoplasmic sink for degradation factors. By regulating the access of the cytosol to proteins involved in mRNA turnover, P bodies can modulate mRNA stability. This suggests a role for P bodies under stress and their potential importance in stress adaptation.
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| 9. |
- Paakkola, N.-M., et al.
(författare)
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The prognostic and predictive impact of low estrogen receptor expression in early breast cancer : a systematic review and meta-analysis
- 2021
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Ingår i: ESMO Open. - : Elsevier. - 2059-7029. ; 6:6
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Forskningsöversikt (refereegranskat)abstract
- INTRODUCTION: Traditionally, estrogen receptor (ER)-positive breast cancer has been defined as tumors with ≥1% positive for ER. The updated American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines recommend that tumors with ER expression of 1%-10% should be classified as ER-low-positive, recognizing the limited clinical evidence on the prognostic and predictive role of low ER expression. We aimed to investigate the predictive role of ER-low expression to neoadjuvant chemotherapy (NeoCT) and the prognostic significance of ER-low expressing breast tumors compared with ER-positive or ER-negative breast tumors.METHODS: A meta-analysis was conducted using the Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines and eligible articles were identified on PubMed and ISI Web of Science databases. The primary outcome was pathologic complete response and secondary outcomes were disease-free survival (DFS) and overall survival (OS). Twelve retrospective cohort studies were included in the meta-analysis. NeoCT resulted in higher pathologic complete response among patients with ER-low expression compared with ER-positive and comparable to ER-negative. Patients with ER-low breast cancer had a statistically significant worse DFS and OS compared with patients with ER-positive breast cancer, whereas no difference in DFS or OS was observed between ER-low and ER-negative subgroups.DISCUSSION: The current evidence suggests that ER-low breast cancer has a more similar outcome to ER-negative than to ER-positive breast cancer in terms of DFS and OS. ER-low expression seems also to have a predictive role regarding NeoCT. Considering the certainty of current evidence categorized as low to moderate, our results urge the need for well-designed prospective studies investigating the molecular background and the most appropriate treatment strategy for ER-low expressing breast cancer.
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| 10. |
- Giubertoni, Giulia, et al.
(författare)
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Strong reduction of the chain rigidity of hyaluronan by selective binding of Ca2+ ions
- 2021
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 54:3, s. 1137-1146
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Tidskriftsartikel (refereegranskat)abstract
- The biological functions of natural polyelectrolytes are strongly influenced by the presence of ions, which bind to the polymer chains and thereby modify their properties. Although the biological impact of such modifications is well recognized, a detailed molecular picture of the binding process and of the mechanisms that drive the subsequent structural changes in the polymer is lacking. Here, we study the molecular mechanism of the condensation of calcium, a divalent cation, on hyaluronan, a ubiquitous polymer in human tissues. By combining two-dimensional infrared spectroscopy experiments with molecular dynamics simulations, we find that calcium specifically binds to hyaluronan at millimolar concentrations. Because of its large size and charge, the calcium cation can bind simultaneously to the negatively charged carboxylate group and the amide group of adjacent saccharide units. Molecular dynamics simulations and single-chain force spectroscopy measurements provide evidence that the binding of the calcium ions weakens the intramolecular hydrogen-bond network of hyaluronan, increasing the flexibility of the polymer chain. We also observe that the binding of calcium to hyaluronan saturates at a maximum binding fraction of ∼10–15 mol %. This saturation indicates that the binding of Ca2+ strongly reduces the probability of subsequent binding of Ca2+ at neighboring binding sites, possibly as a result of enhanced conformational fluctuations and/or electrostatic repulsion effects. Our findings provide a detailed molecular picture of ion condensation and reveal the severe effect of a few, selective and localized electrostatic interactions on the rigidity of a polyelectrolyte chain.
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