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- Emgård-Mattson, Mia, et al.
(författare)
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Both apoptosis and necrosis occur early after intracerebral grafting of ventral mesencephalic tissue: a role for protease activation.
- 2003
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 86:5, s. 1223-1232
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Tidskriftsartikel (refereegranskat)abstract
- Neural transplantation is an experimental treatment for Parkinson's disease. Widespread clinical application of the grafting technique is hampered by a relatively poor survival (around 10%) of implanted embryonic dopamine neurones. Earlier animal studies have indicated that a large proportion of the grafted cells die during graft tissue preparation and within the first few days after intracerebral implantation. The present study was designed to reveal the prevalence of cell death in rat intrastriatal grafts at 90 min, 1, 3, 6 and 42 days after implantation. We examined apoptotic cell death using semi-thin and paraffin sections stained with methylene blue and an antibody against activated caspase 3, respectively. We identified abundant apoptotic cell death up to 3 days after transplantation. In addition, we studied calpain activation using an antibody specific for calpain-cleaved fodrin. We report a peak in calpain activity 90 min after grafting. Surprisingly, we did not observe any significant difference in the number of dopaminergic neurones over time. The present results imply that grafted cells may be victims of either an early necrotic or a later apoptotic cell death and that there is substantial cell death as early as 90 min after implantation.
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| 2. |
- Feng, c, et al.
(författare)
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Arabidopsis MYB68 in development and responses to environmental cues. Plant Science 167
- 2004
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Ingår i: Plant Science. - : Elsevier BV. - 0168-9452. ; 167:5, s. 1099-1107
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Tidskriftsartikel (refereegranskat)abstract
- The Arabidopsis MYB68 gene encodes a MYB family protein with N-terminal R2R3 DNA-binding domains. Analyses of MYB68 expression by RNA blot and a transposant gene-trap MYB68::GUS reporter indicated that MYB68 is expressed specifically in root pericycle cells. Root cultures of the myb68 mutant, caused by the gene trap insertion in the first MYB68 exon, produced increased biomass and lignin levels compared to wild type. Under high temperature regimes, MYB68::GUS activity was elevated in roots, while vegetative growth of myb68 mutants was reduced compared to wild type. These data suggest that MYB68 is involved in some step(s) in root development. The closest MYB68 homolog, MYB84, exhibited an overlapping expression pattern in pericycle cells, suggesting that their functions may be partly redundant.
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| 3. |
- Holmquist, J, et al.
(författare)
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Application of the PROFILE model to estimate potassium release from mineral weathering in Northern European agricultural soils
- 2003
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Ingår i: European Journal of Agronomy. - 1161-0301. ; 20:1-2, s. 149-163
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Tidskriftsartikel (refereegranskat)abstract
- Negative potassium (K) balances have been reported from grass-dominated organic systems in several European countries, and in these systems delivery of K from soil primary minerals by weathering is probably crucial to sustained productivity. Mass balances and K budgets have been made at eight grass-dominated experimental agricultural systems, one each in Scotland and Sweden and six in Norway. Where no fertiliser K was applied, the deficits obtained were in the range 35–241 kg K ha−1 per year. An estimate of the weathering rate was determined by the biogeochemical PROFILE model that varied widely between locations (3–82 kg K ha−1 per year). This paper is a first attempt to apply the steady-state PROFILE model on agricultural soils by using data from experimental sites. The Monte Carlo simulation of the weathering rate calculation showed that differences in specific surface area and soil water content strongly influenced the predicted weathering rate, which was associated with a degree of uncertainty. All sites showed a negative annual K-balance, which means that the specific contribution that mineral weathering makes to the long-term replenishment of soil exchangeable-K is important but may not be sufficient to counteract large K removal associated with high crop yields. Despite the uncertainties in the weathering rate calculation, these preliminary results are still useful in several aspects because the simulations make it possible to compare different agroecosystems with different management regimes, climate, soil properties, etc. The simulations also indicate which environmental factors are likely to be the most influential on weathering rates. Soil physical properties, such as moisture content, bulk density and surface area, appeared to be amongst the most important input parameters controlling actual weathering rates within groups of soils having similar mineralogical and chemical compositions. There is now a need for improved laboratory experimental data that better describe the kinetics of mineral weathering in order to enhance the accuracy and precision of PROFILE.
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