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- Mendrik, AM, et al.
(författare)
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MRBrainS Challenge: Online Evaluation Framework for Brain Image Segmentation in 3T MRI Scans
- 2015
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Ingår i: Computational Intelligence and Neuroscience. - : Hindawi Publishing Corporation. - 1687-5265 .- 1687-5273. ; 2015
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Tidskriftsartikel (refereegranskat)abstract
- Many methods have been proposed for tissue segmentation in brain MRI scans. The multitude of methods proposed complicates the choice of one method above others. We have therefore established the MRBrainS online evaluation framework for evaluating (semi)automatic algorithms that segment gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) on 3T brain MRI scans of elderly subjects (65–80 y). Participants apply their algorithms to the provided data, after which their results are evaluated and ranked. Full manual segmentations of GM, WM, and CSF are available for all scans and used as the reference standard. Five datasets are provided for training and fifteen for testing. The evaluated methods are ranked based on their overall performance to segment GM, WM, and CSF and evaluated using three evaluation metrics (Dice, H95, and AVD) and the results are published on the MRBrainS13 website. We present the results of eleven segmentation algorithms that participated in the MRBrainS13 challenge workshop at MICCAI, where the framework was launched, and three commonly used freeware packages: FreeSurfer, FSL, and SPM. The MRBrainS evaluation framework provides an objective and direct comparison of all evaluated algorithms and can aid in selecting the best performing method for the segmentation goal at hand.
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- El-Sayed, Ashraf S.A., et al.
(författare)
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Production, bioprocess optimization and anticancer activity of Camptothecin from Aspergillus terreus and Aspergillus flavus, endophytes of Ficus elastica
- 2021
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Ingår i: Process Biochemistry. - : Elsevier. - 1359-5113 .- 1873-3298. ; 107, s. 59-73
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Tidskriftsartikel (refereegranskat)abstract
- Attenuating the biosynthetic potency of camptothecin producing fungi with the multiple subculturing and storage is the major challenge that limits the scaling-up of this approach. Thus, screening for novel fungal isolates with reliable metabolic stability and sustainability for camptothecin production is the objective of this work. Among the recovered isolates, Aspergillus terreus (320 μg/l) and A. flavus (290 μg/l) "endophytes of Ficus elastica" were the most potent camptothecin producing isolates. The chemical identity of extracted camptothecin was resolved from the HPLC, NMR, FTIR and LC–MS analyses, with a strong antiproliferative activity against MCF7 (0.18 μM), LS174 T, HCT29 (0.29−0.43 μM), HEPG-2 (0.73 μM) cell lines. The yield of camptothecin was decreased by about > 60 % by the 7th subculturing for both fungal isolates. Upon using Blackett-Burman design to optimize their nutritional requirements by the fungal isolates, their yield of camptothecin were increased by approximately 2 folds, revealing the essentiality of some carbon, nitrogen and growth elicitors for biosynthesis of camptothecin. Interestingly, the biosynthetic machinery of camptothecin by the 7th generation fungal isolates were completely restored upon addition of 1% surface sterilized leaves of F. elastica, while all the other experimented plant extracts did not display any effect on camptothecin production. So, chemicals signals derived from the plant /or its entire microbiome "microbial communication" triggering the expression of camptothecin biosynthetic gene cluster of these fungi, could be the most conceivable hypothesis explaining the attenuation and restoration processes of camptothecin biosynthesis by target the fungal isolates. This is the first report describing the feasibility of A. terreus and A. flavus "endophytes of F. elastica" for camptothecin production with reliable metabolic and sustainable biosynthetic potency upon addition of the plant host's entire microbiome, that could be a preliminary platform for scaling-up of camptothecin production.
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| 10. |
- El-Sayed, Ashraf S. A., et al.
(författare)
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Purification and biochemical characterization of taxadiene synthase from bacillus koreensis and stenotrophomonas maltophilia
- 2021
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Ingår i: Scientia pharmaceutica. - : MDPI. - 0036-8709 .- 2218-0532. ; 89:4
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Tidskriftsartikel (refereegranskat)abstract
- Taxadiene synthase (TDS) is the rate-limiting enzyme of Taxol biosynthesis that cyclizes the geranylgeranyl pyrophosphate into taxadiene. Attenuating Taxol productivity by fungi is the main challenge impeding its industrial application; it is possible that silencing the expression of TDS is the most noticeable genomic feature associated with Taxol-biosynthetic abolishing in fungi. As such, the characterization of TDS with unique biochemical properties and autonomous expression that is independent of transcriptional factors from the host is the main challenge. Thus, the objective of this study was to kinetically characterize TDS from endophytic bacteria isolated from different plants harboring Taxol-producing endophytic fungi. Among the recovered 23 isolates, Bacillus koreensis and Stenotrophomonas maltophilia achieved the highest TDS activity. Upon using the Plackett–Burman design, the TDS productivity achieved by B. koreensis (18.1 µmol/mg/min) and S. maltophilia (14.6 µmol/mg/min) increased by ~2.2-fold over the control. The enzyme was purified by gel-filtration and ion-exchange chromatography with ~15 overall folds and with molecular subunit structure 65 and 80 kDa from B. koreensis and S. maltophilia, respectively. The chemical identity of taxadiene was authenticated from the GC-MS analyses, which provided the same mass fragmentation pattern of authentic taxadiene. The tds gene was screened by PCR with nested primers of the conservative active site domains, and the amplicons were sequenced, displaying a higher similarity with tds from T. baccata and T. brevifolia. The highest TDS activity by both bacterial isolates was recorded at 37–40 °C. The Apo-TDSs retained ~50% of its initial holoenzyme activities, ensuring their metalloproteinic identity. The activity of purified TDS was completely restored upon the addition of Mg2+, confirming the identity of Mg2+ as a cofactor. The TDS activity was dramatically reduced upon the addition of DTNB and MBTH, ensuring the implementation of cysteine-reactive thiols and ammonia groups on their active site domains. This is the first report exploring the autonomous robust expression TDS from B. koreensis and S. maltophilia with a higher affinity to cyclize GGPP into taxadiene, which could be a novel platform for taxadiene production as intermediary metabolites of Taxol biosynthesis.
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| 11. |
- Marco, M., et al.
(författare)
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A relevant enzyme in granulomatous reaction, active matrix metalloproteinase-9, found in bovine Echinococcus granulosus hydatid cyst wall and fluid
- 2006
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Ingår i: Parasitology Research. - : Springer Science and Business Media LLC. - 0932-0113 .- 1432-1955. ; 100:1, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- In addition to the ability of matrix metalloproteinases (MMP) to degrade components of the extracellular matrix and their involvement in pathology-related processes of tissue remodeling, they were recently reported to enhance inflammation by activation of proinflammatory cytokines, or their release from the cell surface. In the work reported here, proteolytic activity previously found for hydatid cysts was further characterized as MMP-9. Active host MMP-9 was found in walls and fluids of bovine hydatid cysts of Echinococcus granulosus in the environment of granulomatous reaction. Pooled walls and fluids of hydatid cysts obtained from infected cattle were processed. Strong proteolytic activity was detected by zymography. The proteolytic fraction was purified by anion exchange and gelatin-agarose affinity chromatography. Major proteinases of the purified fraction were subjected to mass spectrometry and their identities were further confirmed by Western blotting using commercial anti-human MMP-9 monoclonal antibodies. Two proteinases were characterized as latent and active forms of host MMP-9. Using the same antibody for immunoblot, activity was localized, in paraffin-embedded sections of the parasite and the local host environment, to epithelioid and giant multinucleated cells. It is proposed here that MMP-9 is secreted by specialized host cells of monocytic lineage (epithelioid/giant cells) as an effector, in an attempt to digest the persistent foreign body. In vivo activation of MMP-9 suggests its involvement in inflammatory reaction and in the chemotaxis of inflammatory cells to the cyst. However, E. granulosus can deal efficiently with MMP-9. Research is suggested into possible immune evasion mechanisms, including the secretion of an inhibitory molecule.
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- Ousmaal, Mohamed E.F., et al.
(författare)
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Circulating microparticles released during dyslipidemia may exert deleterious effects on blood vessels and endothelial function
- 2020
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Ingår i: Journal of Diabetes and its Complications. - : Elsevier BV. - 1056-8727. ; 34:10
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To compare the bioactivity of circulating microparticles (MPs) isolated from dyslipidemic Psammomys obesus (P. obesus) fed a high-energy diet (HED) with those released from healthy P. obesus fed a normal diet (ND). Methods: Vascular reactivity of aortic rings was evaluated by myography, after 24 h incubation in the absence or in the presence of circulating MPs isolated, by differential centrifugations, from the plasma of animals subjected to HED (MPsHED) or ND (MPsND) for 12 weeks. Human umbilical vein endothelial cells (HUVECs) were treated for 24 h with MPsHED or MPsND animals and subjected to immunofluorescence staining of caveolin-1 (cav-1), intercellular adhesion molecule-1 (ICAM-1), endothelial nitric oxide synthase (eNOS), F-actin and reactive oxygen species (ROS) detection. Results: The HED exerted a distinctly pronounced hyperlipidemic effect marked by plasmatic increase of total cholesterol, low-density lipoprotein-cholesterol (LDL-C) and triglyceride (TG). Both MPsND and MPsHED induced a significant reduction of maximal relaxation induced by acetylcholine (ACh). Interestingly, MPsHED significantly decreased eNOS expression up to ~25% and increased ROS production up to ~75% on in vitro treated HUVECs. Moreover, in HUVECs, MPsHED significantly decreased cav-1 expression up to ~50% whereas significant increase of ICAM-1 expression by about 2-fold approximately was observed. Conclusion: Our experimental study demonstrated the dual role of MPs on vascular function by modulating endothelial cell function. Furthermore, MPs may be considered as vectors of a bioactive information contributing to inflammation and vascular damage.
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