| 1. |
- Andersen, Felicie F., et al.
(författare)
-
Assembly and structural analysis of a covalently closed nano-scale DNA cage
- 2008
-
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 36:4, s. 1113-1119
-
Tidskriftsartikel (refereegranskat)abstract
- The inherent properties of DNA as a stable polymer with unique affinity for partner mols. detd. by the specific Watson-Crick base pairing makes it an ideal component in self-assembling structures. This has been exploited for decades in the design of a variety of artificial substrates for investigations of DNA-interacting enzymes. More recently, strategies for synthesis of more complex two-dimensional (2D) and 3D DNA structures have emerged. However, the building of such structures is still in progress and more experiences from different research groups and different fields of expertise are necessary before complex DNA structures can be routinely designed for the use in basal science and/or biotechnol. Here we present the design, construction and structural anal. of a covalently closed and stable 3D DNA structure with the connectivity of an octahedron, as defined by the double-stranded DNA helixes that assembles from eight oligonucleotides with a yield of .apprx.30%. As demonstrated by Small Angle X-ray Scattering and cryo-Transmission Electron Microscopy analyses the eight-stranded DNA structure has a central cavity larger than the apertures in the surrounding DNA lattice and can be described as a nano-scale DNA cage, Hence, in theory it could hold proteins or other bio-mols. to enable their investigation in certain harmful environments or even allow their organization into higher order structures.
|
|
| 2. |
- Andersen, Naja Steen, et al.
(författare)
-
Processes affecting genetic structure and conservation: a case study of wild and cultivated Brassica rapa
- 2009
-
Ingår i: Genetic Resources and Crop Evolution. - Dordrecht : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 56:2, s. 189-200
-
Tidskriftsartikel (refereegranskat)abstract
- When planning optimal conservation strategies for wild and cultivated types of a plant species, a number of influencing biological and environmental factors should be considered from the outset. In the present study Brassica rapa was used to illustrate this: to develop Scandinavian conservation strategies for wild and cultivated B. rapa, DNA-marker analysis was performed on 15 cultivated and 17 wild accessions of B. rapa plus 8 accessions of the cross compatible B. napus. The B. rapa cultivars were bred in Sweden and Finland in 1944-1997 and the wild B. rapa material was collected from Denmark, Sweden and United Kingdom. The B. napus accessions were bred within the last 20 years in the Scandinavian countries. Results were based on scoring of 131 polymorphic ISSR markers in the total plant material. A Bayesian Markov chain Monte Carlo (MCMC) approach implemented in NewHybrids demonstrated a clear distinction of B. rapa and B. napus individuals except for three individuals that seemed to be backcrosses. The backcrossed hybrids descended from two Swedish populations, one wild and one escaped. The overall pattern of genetic variation and structure in B. rapa showed that cultivated and wild B. rapa accessions formed two almost separated clusters. Geographical origin and breeding history of cultivars were reflected in these genetic relationships. In addition, wild populations from Denmark and Sweden seemed to be closely related, except for a Swedish population, which seemingly was an escaped cultivar. The study point to that many processes, e.g. spontaneous introgression, naturalisation, breeding and agricultural practise affected the genetic structure of wild and cultivated B. rapa populations.
|
|
| 3. |
- Jorgensen, Rikke Bagger, et al.
(författare)
-
The variability of processes involved in transgene dispersal-case studies from Brassica and related genera
- 2009
-
Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 1614-7499 .- 0944-1344. ; 16:4, s. 389-395
-
Forskningsöversikt (refereegranskat)abstract
- Background, aim, and scope We strive to predict consequences of genetically modified plants (GMPs) being cultivated openly in the environment, as human and animal health, biodiversity, agricultural practise and farmers' economy could be affected. Therefore, it is unfortunate that the risk assessment of GMPs is burdened by uncertainty. One of the reasons for the uncertainty is that the GMPs are interacting with the ecosystems at the release site thereby creating variability. This variability, e. g. in gene flow, makes consequence analysis difficult. The review illustrates the great uncertainty of results from gene-flow analysis. Main features Many independent experiments were performed on the individual processes in gene flow. The results comprise information both from laboratory, growth chambers and field trials, and they were generated using molecular or phenotypic markers and analysis of fitness parameters. Monitoring of the extent of spontaneous introgression in natural populations was also performed. Modelling was used as an additional tool to identify key parameters in gene flow. Results The GM plant may affect the environment directly or indirectly by dispersal of the transgene. Magnitude of the transgene dispersal will depend on the GM crop, the agricultural practise and the environment of the release site. From case-to-case these three factors provide a variability that is reflected in widely different likelihoods of transgene dispersal and fitness of introgressed plants. In the present review, this is illustrated through a bunch of examples mostly from our own research on oilseed rape, Brassica napus. In the Brassica cases, the variability affected all five main steps in the process of gene dispersal. The modelling performed suggests that in Brassica, differences in fitness among plant genome classes could be a dominant factor in the establishment and survival of introgressed populations. Discussion Up to now, experimental analyses have mainly focused on studying the many individual processes of gene flow. This can be criticised, as these experiments are normally carried out in widely different environments and with different genotypes, and thus providing bits and pieces difficult to assemble. Only few gene-flow studies have been performed in natural populations and over several plant generations, though this could give a more coherent and holistic view. Conclusion The variability inherent in the processes of gene flow in Brassica is apparent and remedies are wished for. One possibility is to expose the study species to additional experiments and monitoring, but this is costly and will likely not cover all possible scenarios. Another remedy is modelling gene flow. Modelling is a valuable tool in identifying key factors in the gene-flow process for which more knowledge is needed, and identifying parameters and processes which are relatively insensitive to change and therefore require less attention in future collections of data. But the interdependence between models and experimental data is extensive, as models depend on experimental data for their development or testing. Recommendations More and more transgenic varieties are being grown worldwide harbouring genes that might potentially affect the environment ( e. g. drought tolerance, salt tolerance, disease tolerance, pharmaceutical genes). This calls for a thorough risk assessment. However, in Brassica, the limited and uncertain knowledge on gene flow is an obstacle to this. Modelling of gene flow should be optimised, and modelling outputs verified in targeted field studies and at the landscape level. Last but not least, it is important to remember that transgene flow in itself is not necessarily a thread, but it is the consequences of gene flow that may jeopardise the ecosystems and the agricultural production. This emphasises the importance of consequence analysis of genetically modified plants.
|
|
| 4. |
|
|
| 5. |
- Olsen, Rikke K J, et al.
(författare)
-
ETFDH mutations as a major cause of riboflavin-responsive multiple acyl-CoA dehydrogenation deficiency.
- 2007
-
Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 130:Pt 8, s. 2045-54
-
Tidskriftsartikel (refereegranskat)abstract
- Multiple acyl-CoA dehydrogenation deficiency (MADD) is a disorder of fatty acid, amino acid and choline metabolism that can result from defects in two flavoproteins, electron transfer flavoprotein (ETF) or ETF: ubiquinone oxidoreductase (ETF:QO). Some patients respond to pharmacological doses of riboflavin. It is unknown whether these patients have defects in the flavoproteins themselves or defects in the formation of the cofactor, FAD, from riboflavin. We report 15 patients from 11 pedigrees. All the index cases presented with encephalopathy or muscle weakness or a combination of these symptoms; several had previously suffered cyclical vomiting. Urine organic acid and plasma acyl-carnitine profiles indicated MADD. Clinical and biochemical parameters were either totally or partly corrected after riboflavin treatment. All patients had mutations in the gene for ETF:QO. In one patient, we show that the ETF:QO mutations are associated with a riboflavin-sensitive impairment of ETF:QO activity. This patient also had partial deficiencies of flavin-dependent acyl-CoA dehydrogenases and respiratory chain complexes, most of which were restored to control levels after riboflavin treatment. Low activities of mitochondrial flavoproteins or respiratory chain complexes have been reported previously in two of our patients with ETF:QO mutations. We postulate that riboflavin-responsive MADD may result from defects of ETF:QO combined with general mitochondrial dysfunction. This is the largest collection of riboflavin-responsive MADD patients ever reported, and the first demonstration of the molecular genetic basis for the disorder.
|
|
| 6. |
- Wejse, Christian, et al.
(författare)
-
Serum 25-hydroxyvitamin D in a West African population of tuberculosis patients and unmatched healthy controls
- 2007
-
Ingår i: American Journal of Clinical Nutrition. - 1938-3207. ; 86:5, s. 1376-1383
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Little is known regarding vitamin D deficiency (VDD) in African populations and in tuberculosis (TB) patients. VDD has been shown to be associated with TB. Objective: We aimed to compare the degree of vitamin D insufficiency (VDI) and VDD in TB patients and healthy adult controls in a West African population. Design: An unmatched case-control study was performed at a Demographic Surveillance Site in Guinea-Bissau. Serum 25-hydroxyvitamin D-3 [25(OH)D-3] concentrations were measured in 362 TB patients and in 494 controls. Results: Hypovitammosis D [25(OH)D-3 <= 75 nmol/L] was more common in TB patients, but VDD [25(OH)D-3 <= 50 nmol/L] was more common and more severe in controls. We observed hypovitaminosis D in 467o (167/362) of the TB patients and in 39% (193/494) of the controls: the relative risk (RR) of hypovitaminosis D was 1.18 (95% Cl: 1.01. 1.38). VDD was observed in 8.5% (31/362) of the TB patients and in 13.2% (65/494) of the controls. The RR was 0.65 (95% Cl: 0.43,0.98), mainly because severe VDD [25(OH)D-3 <= 25 nmol/L] was observed in only I of 362 TB patients (0.2%) and in 24 of 494 controls (4.9%). After adjustment for background factors, hypovitaminosis D was not more frequent in TB patients than in healthy controls, but the mean serum 25(OH)D3 concentration remained lower. Conclusions: Hypovitammosis D was highly prevalent in TB patients and in healthy controls living at 12 degrees N; severe VDD was rare in TB patients. The finding indicates that the serum 25(OH)D3 concentration is associated with TB infection, but whether this role is a symptom or is causal was not established.
|
|
