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- Wicher, K. B., et al.
(författare)
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Deletion of a cytotoxic, N-terminal putative signal peptide results in a significant increase in production yields in Escherichia coli and improved specific activity of Cel12A from Rhodothermus marinus
- 2001
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Ingår i: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 0175-7598 .- 1432-0614. ; 55:5, s. 578-584
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Tidskriftsartikel (refereegranskat)abstract
- The thermostable cellulase Cel12A from Rhodothermus marinus was produced at extremely low levels when expressed in Escherichia coli and was cytotoxic to the cells. In addition, severe aggregation occurred when moderately high concentrations of the enzyme were heat-treated at 65°C, the growth optimum of R. marinus. Sequence analysis revealed that the catalytic module of this enzyme is preceded by a typical linker sequence and a highly hydrophobic putative signal peptide. Two deletion mutants lacking this hydrophobic region were cloned and successfully expressed in E. coli. These results indicated that the N-terminal putative signal peptide was responsible for the toxicity of the full-length enzyme in the host organism. This was further corroborated by cloning and expressing the hydrophobic N-terminal domain in E. coli, which resulted in extensive cell lysis. The deletion mutants, made up of either the catalytic module of Cel12A or the catalytic module and the putative linker sequence, were characterised and their properties compared to those of the full-length enzyme. The specific activity of the mutants was approximately threefold higher than that of the full-length enzyme. Both mutant proteins were highly thermostable, with half-lives exceeding 2 h at 90°C and unfolding temperatures up to 103°C.
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| 2. |
- Enoksson, Mattias, et al.
(författare)
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Intraperitoneal influx of neutrophils in response to IL-33 is mast cell-dependent
- 2013
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 121:3, s. 530-536
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Tidskriftsartikel (refereegranskat)abstract
- IL-33 is a recently discovered cytokine involved in induction of Th2 responses and functions as an alarmin. Despite numerous recent studies targeting IL-33, its role in vivo is incompletely understood. Here we investigated inflammatory responses to intraperitoneal IL-33 injections in wild-type and mast cell–deficient mice. We found that wild-type mice, but not mast cell–deficient Wsh/Wsh mice, respond to IL-33 treatment with neutrophil infiltration to the peritoneum, whereas other investigated cell types remained unchanged. In Wsh/Wsh mice, the IL-33–induced innate neutrophil response could be rescued by local reconstitution with wild-type but not with T1/ST2−/− mast cells, demonstrating a mast cell–dependent mechanism. Furthermore, we found this mechanism to be partially dependent on mast cell–derived TNF, as we observed reduced neutrophil infiltration in Wsh/Wsh mice reconstituted with TNF−/− bone marrow–derived mast cells compared with those reconstituted with wild-type bone marrow–derived mast cells. In agreement with our in vivo findings, we demonstrate that humanneutrophils migrate toward the supernatant of IL-33–treated human mast cells. Taken together, our findings reveal that IL-33 activates mast cells in vivo to recruit neutrophils, a mechanism dependent on IL-33R expression on peritoneal mast cells. Mast cells activated in vivo by IL-33 probably play an important role in inflammatory reactions.
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| 4. |
- Strzelecki, G. W., et al.
(författare)
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Multi-component low and high entropy metallic coatings synthesized by pulsed magnetron sputtering
- 2022
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 446
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the findings of the synthesis of multicomponent (Al, W, Ni, Ti, Nb) alloy coatings from mosaic targets. For the study, a pulsed magnetron sputtering method was employed under different plasma generation conditions: modulation frequency (10 Hz and 1000 Hz), and power (600 W and 1000 W). The processes achieved two types of alloy coatings, high entropy and classical alloys. After the deposition processes, scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy techniques were employed to find the morphology, thickness, and chemical and phase compositions of the coatings. Nanohardness and its related parameters, namely H-3/E-r(2), H/E, and 1/(ErH)-H-2 ratios, were measured. An annealing treatment was performed to estimate the stability range for the selected coatings. The results indicated the formation of as-deposited coatings exhibiting an amorphous structure as a single-phase solid solution. The process parameters had an influence on the resulting morphology & mdash;a dense and homogenous as well as a columnar morphology, was obtained. The study compared the properties of high-entropy alloy (HEA) coatings and classical alloy coatings concerning their structure and chemical and phase composition. It was found that the change of frequency modulation and the post-annealing process contributed to the increase in the hardness of the material in the case of HEA coatings.
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