| 1. |
- Haas, Brian J., et al.
(författare)
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Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans
- 2009
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 461:7262, s. 393-398
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Tidskriftsartikel (refereegranskat)abstract
- Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement(1). To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the world's population(1). Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion(2). Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars(3,4). Here we report the sequence of the P. infestans genome, which at similar to 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for similar to 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
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| 2. |
- Liu, Lei, et al.
(författare)
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Immunological responses in mice to full-thickness corneal grafts engineered from porcine collagen
- 2007
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Ingår i: Biomaterials. - : Elsevier. - 0142-9612 .- 1878-5905. ; 28:26, s. 3807-3814
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Tidskriftsartikel (refereegranskat)abstract
- Tissue-engineered (TE) corneas were fabricated from porcine collagen cross-linked with 1-ethyl-3-(3-dimethyl aminoproplyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and were transplanted into BALB/c mice orthotopically using a full-thickness penetrating keratoplasty (PKP) procedure. The biocompatibility was evaluated by assessing both local and systemic immune responses. Myeloid cells including granulocytes and macrophages were the main infiltrating cells in recipient cornea and in retro-TE corneal membrane which developed 7-10 days post surgery. Sodium citrate was found to be effective in reducing fibrin accumulation in anterior chamber post grafting at early time points, but it did not prevent formation of the retro-TE corneal membrane. No significant T cell activation was observed in the submandibular draining lymph nodes (SMDLN) by flow cytometry. Anti-porcine type I collagen IgG antibodies were detected in the serum of grafted mice from 2 weeks post grafting and the concentration of antibodies increased with time. Overall, porcine collagen-EDC/NHS TE corneas were tolerated well in murine recipients, causing mainly a self-limiting local innate immune response and a low-grade humoral response with little evidence of sustained T cell activation. Retro-TE corneal membrane formation was the main complication and barrier to clarity.
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| 3. |
- McLaughlin, Christopher, et al.
(författare)
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Regeneration of Corneal Cells and Nerves in an Implanted Collagen Corneal Substitute
- 2008
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Ingår i: Cornea. - 0277-3740 .- 1536-4798. ; 27:5, s. 580-589
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Our objective was to evaluate promotion of tissue regeneration by extracellular matrix (ECM) mimics, by using corneal implantation as a model system.METHODS: Carbodiimide cross-linked porcine type I collagen was molded into appropriate corneal dimensions to serve as substitutes for natural corneal ECM. These were implanted into corneas of mini-pigs after removal of the host tissue, and tracked over 12 months, by clinical examination, slit-lamp biomicroscopy, in vivo confocal microscopy, topography, and esthesiometry. Histopathology and tensile strength testing were performed at the end of 12 months. Other samples were biotin labeled and implanted into mice to evaluate matrix remodeling.RESULTS: The implants promoted regeneration of corneal cells, nerves, and the tear film while retaining optical clarity. Mechanical testing data were consistent with stable, seamless host-graft integration in regenerated corneas, which were as robust as the untreated fellow corneas. Biotin conjugation is an effective method for tracking the implant within the host tissue.CONCLUSIONS: We show that a simple ECM mimetic can promote regeneration of corneal cells and nerves. Gradual turnover of matrix material as part of the natural remodeling process allowed for stable integration with host tissue and restoration of mechanical properties of the organ. The simplicity in fabrication and shown functionality shows potential for ECM
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| 4. |
- Suuronen, Erik J., et al.
(författare)
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Tissue-engineered injectable collagen-based matrices for improved cell delivery and vascularization of ischemic tissue using CD133+progenitors expanded from the peripheral blood
- 2006
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Ingår i: Circulation. - : LIPPINCOTT WILLIAMS and WILKINS. - 0009-7322 .- 1524-4539. ; 114, s. I138-I144
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Tidskriftsartikel (refereegranskat)abstract
- Background-The use of stem and/or progenitor cells to achieve potent vasculogenesis in humans has been hindered by low cell numbers, implant capacity, and survival. This study investigated the expansion of CD133(+) cells and the use of an injectable collagen-based tissue engineered matrix to support cell delivery and implantation within target ischemic tissue. Methods and Results-Adult human CD133(+) progenitor cells from the peripheral blood were generated and expanded by successive removal and culture of CD133(-) cell fractions, and delivered within an injectable collagen-based matrix into the ischemic hindlimb of athymic rats. Controls received injections of phosphate-buffered saline, matrix, or CD133(+) cells alone. Immunohistochemistry of hindlimb muscle 2 weeks after treatment revealed that the number of CD133(+) cells retained within the target site was greater than 2-fold greater when delivered by matrix than when delivered alone (P less than 0.01). The transplanted CD133(+) cells incorporated into vascular structures, and the matrix itself also was vascularized. Rats that received matrix and CD133(+) cells demonstrated greater intramuscular arteriole and capillary density than other treatment groups (P less than 0.05 and P less than 0.01, respectively). Conclusions-Compared with other experimental approaches, treatment of ischemic muscle tissue with generated CD133(+) progenitor cells delivered in an injectable collagen-based matrix significantly improved the restoration of a vascular network. This work demonstrates a novel approach for the expansion and delivery of blood CD133(+) cells with resultant improvement of their implantation and vasculogenic capacity.
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