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- Sodergren, Erica, et al.
(author)
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The genome of the sea urchin Strongylocentrotus purpuratus.
- 2006
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In: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
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Journal article (peer-reviewed)abstract
- We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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- Chang, Christine Chi-Chen, 1974-
(author)
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Mechanisms and genes controlling the signalling network for biotic and abiotic stress defences in Arabidopsis thaliana (L.) Heyhn : Functional cross-talk between photo-produced reactive oxygen species, photosynthesis and plant disease defence responses
- 2005
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Doctoral thesis (other academic/artistic)abstract
- Excess excitation energy, mechanical injury and defence against pathogens, each trigger rapid production of reactive oxygen species (ROS) in Arabidopsis thaliana leaves. ROS, such as hydrogen peroxide (H2O2), are required for the induction of systemic acquired acclimation and may lead to redox changes in photosynthetic electron transport (PET). On one hand, enhanced ROS production during stress can destroy cells, and on the other, ROS can also act as signals for the activation of stress responsive and defensive pathways.In this work, physiological and molecular analyses of Arabidopsis mutants and transgenic lines were applied to investigate the signalling network controlling biotic and abiotic stress responses. A key enzyme of the antioxidant network is encoded by ASCORBATE PEROXIDASE 2 (APX2). Wounded leaves showed low induction of APX2 expression and when exposed to excess light, APX2 expression was increased synergistically. Signalling pathways dependent upon jasmonic acid, chitosan and abscisic acid were not involved in the wound-induced expression of APX2, but PET was required, and APX2 induction was preceded by a depressed rate of CO2 fixation.Analysis of lsd1 (LESION SIMULATING DISEASE 1) strongly suggests that light acclimatory processes and pathogen defences are genetically and functionally linked. It is important to know that LSD1 type of mutants have mainly been studied with regard to pathogenesis. From this work, it reveals that association of LSD1 with hypersensitive response may only be supplementary.GLUTATHIONE PEROXIDASES (GPXs) are another major family of ROS scavenging enzymes. Analysis of the Arabidopsis genome database revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1-AtGPX8). Arabidopsis thaliana transgenic lines with reduced expression of both putative chloroplastic isoforms (AtGPX1 and AtGPX7) and AtGPX7 knock-out mutant (ko-GPX7) were more sensitive to photo-oxidative stress but had a reduced bacterial growth rate when inoculated with virulent strains Pseudomonas syringae pv. tomato DC3000 and P.s.t. maculicola strain ES4326, indicating increased resistance to pathogenesis. This, to our knowledge, is the first functional and genetic analysis of chloroplastic GPXs in plants, and confirms that light and chloroplastic ROS metabolism is important for basal resistance against virulent pathogens.The above results confirm that light sensing, light acclimatory processes and photo-produced ROS also govern pathogen defence pathways. This has a great ecological relevance for Darwinian fitness of plants growing in the natural environment, where simultaneous pathogen attack and fluctuations in light, temperature and other environmental factors make rapid acclimation a constant necessity. Molecular, biochemical and physiological analysis of pathogen responses in mutants impaired in light sensing, EEE-dissipatory mechanisms, and similar analysis of light acclimatory processes in mutants impaired in pathogen defences may prove to be seminal.
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- Elsik, Christine G., et al.
(author)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Journal article (peer-reviewed)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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4. |
- Hu, Baihua, et al.
(author)
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Discovery of phenyl acetic acid substituted quinolines as novel liver X receptor agonists for the treatment of atherosclerosis
- 2006
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 49:21, s. 6151-6154
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Journal article (peer-reviewed)abstract
- A structure-based approach was used to optimize our new class of quinoline LXR modulators leading to phenyl acetic acid substituted quinolines 15 and 16. Both compounds displayed good binding affinity for LXRâ and LXRR and were potent activators in LBD transactivation assays. The compounds also increased expression of ABCA1 and stimulated cholesterol efflux in THP-1 cells. Quinoline 16 showed good oral bioavailability and in vivo efficacy in a LDLr knockout mouse model for lesions.
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- Achberger, Christine, 1968, et al.
(author)
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The surface winds of Sweden during 1999-2000
- 2006
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In: International Journal of Climatology. - : Wiley. - 0899-8418 .- 1097-0088. ; 26:2, s. 159-178
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Journal article (peer-reviewed)abstract
- This study aims at increasing our understanding of the regional wind climate in Sweden. Spatial and temporal patterns of the surface winds are presented for the years 1999-2000. Annual mean wind speeds range between 2 and 5 m/s with high values at exposed mountainous sites and on islands off the coast. Combining wind speed and direction into mean wind velocities shows that flow conditions are stronger and more coherent in space in southern Sweden than in central and northern Sweden. The spatial scale, defined as the distance between stations when the correlation for wind speed drops to similar to 0.37, was determined by pairwise correlations between all possible station pairs. Scales range from 38 to 530 km for wind speed and from 40 to 830 km for wind direction depending on the region. They tend to be smaller in central and northern Sweden, where the more pronounced relief has a larger influence on the local wind conditions. The strength and the timing of the annual and diurnal wind speed cycle have been estimated for each station. Amplitudes of the annual cycle are greater at exposed sites and correlate generally well with annual mean wind speeds. Monthly mean wind speeds peak in winter in southern Sweden, but peak in other seasons in the remaining regions. In winter, weaker pressure gradients over northern Sweden and surface-near temperature inversions contribute to weaker surface winds. Diurnal cycles vary in strength between summer and winter. Compared to the last normal climate period (1961-1990), 1999-2000 is characterized by the increased occurrence of westerly and southerly geostrophic flow. Copyright (C) 2005 Royal Meteorological Society.
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- Adewumi, Oluseun, et al.
(author)
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Characterization of human embryonic stem cell lines by the International Stem Cell Initiative
- 2007
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In: Nature Biotechnology. - : Springer Science and Business Media LLC. - 1087-0156 .- 1546-1696. ; 25:7, s. 803-816
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Journal article (peer-reviewed)abstract
- The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue- nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allele-specific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.
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