| 1. |
|
|
| 2. |
|
|
| 3. |
- Albers, Eva, 1966, et al.
(författare)
-
Ser3p (Yer081wp) and Ser33p (Yil074cp) are phosphoglycerate dehydrogenases in Saccharomyces cerevisiae
- 2003
-
Ingår i: J Biol Chem. ; 278, s. 10264-10272
-
Tidskriftsartikel (refereegranskat)abstract
- Two genes YER081W and YIL074C, renamed SER3 and SER33, respectively, which encode phosphoglycerate dehydrogenases in Saccharomyces cerevisiae were identified. These dehydrogenases catalyze the first reaction of serine and glycine biosynthesis from the glycolytic metabolite 3-phosphoglycerate. Unlike either single mutant, the ser3Delta ser33Delta double mutant lacks detectable phosphoglycerate dehydrogenase activity and is auxotrophic for serine or glycine for growth on glucose media. However, the requirement for the SER-dependent "phosphoglycerate pathway" is conditional since the "glyoxylate" route of serine/glycine biosynthesis is glucose-repressed. Thus, in cells grown on ethanol both expression and activity of all SER-encoded proteins are low, including the remaining enzymes of the phosphoglycerate pathway, Ser1p and Ser2p. Moreover the available nitrogen source regulates the expression of SER genes. However, for only SER33, and not SER3, expression was regulated in relation to the available nitrogen source in a coordinated fashion with SER1 and SER2. Based on these mRNA data together with data on enzyme activities, Ser33p is likely to be the main isoenzyme of the phosphoglycerate pathway during growth on glucose. Moreover, since phosphoglycerate dehydrogenase activity requires NAD+ as cofactor, deletion of SER3 and SER33 markedly affected redox metabolism as shown by substrate and product analysis.
|
|
| 4. |
- Alpkvist, Erik, et al.
(författare)
-
A new mathematical model for chemotactic bacterial colony growth
- 2004
-
Ingår i: Water Science and Technology. - : Biriwa Education Services. - 0273-1223 .- 1996-9732. ; 49:11-12, s. 187-192
-
Tidskriftsartikel (refereegranskat)abstract
- A new continuum model for the growth of a single species biofilm is proposed. The geometry of the biofilm is described by the interface between the biomass and the surrounding liquid. Nutrient transport is given by the solution of a semi-linear Poisson equation. In this model we study the morphology of a chemotactic bacterial colony, which grows in the direction of increasing nutrient concentration. Numerical simulations using the level set method and finite difference schemes are presented. The results show rich heterogeneous morphology.
|
|
| 5. |
|
|
| 6. |
- Andersson, Anders, et al.
(författare)
-
A transcriptional timetable of autumn senescence
- 2004
-
Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 5:4, s. R24-
-
Tidskriftsartikel (refereegranskat)abstract
- Background We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. Results On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. Conclusions We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.
|
|
| 7. |
|
|
| 8. |
- Bhalerao, Rupali, et al.
(författare)
-
Gene expression in autumn leaves
- 2003
-
Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 131:2, s. 430-442
-
Tidskriftsartikel (refereegranskat)abstract
- Two cDNA libraries were prepared, one from leaves of a field-grown aspen (Populus tremula) tree, harvested just before any visible sign of leaf senescence in the autumn, and one from young but fully expanded leaves of greenhouse-grown aspen (Populus tremula X tremuloides). Expressed sequence tags (ESTs; 5,128 and 4,841, respectively) were obtained from the two libraries. A semiautomatic method of annotation and functional classification of the ESTs, according to a modified Munich Institute of Protein Sequences classification scheme, was developed, utilizing information from three different databases. The patterns of gene expression in the two libraries were strikingly different. In the autumn leaf library, ESTs encoding metallothionein, early light-inducible proteins, and cysteine proteases were most abundant. Clones encoding other proteases and proteins involved in respiration and breakdown of lipids and pigments, as well as stress-related genes, were also well represented. We identified homologs to many known senescence-associated genes, as well as seven different genes encoding cysteine proteases, two encoding aspartic proteases, five encoding metallothioneins, and 35 additional genes that were up-regulated in autumn leaves. We also indirectly estimated the rate of plastid protein synthesis in the autumn leaves to be less that 10% of that in young leaves.
|
|
| 9. |
- Björklund, Stefan, et al.
(författare)
-
The mediator complex
- 2004
-
Ingår i: Advances in protein chemistry. - 0065-3233 .- 1557-8941. ; 67, s. 43-65
-
Tidskriftsartikel (refereegranskat)
|
|
| 10. |
|
|
