| 21. |
- Cao, YH, et al.
(författare)
-
Angiogenesis inhibited by drinking tea
- 1999
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 398:6726, s. 381-381
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 22. |
- Carlsson, Christina, 1968, et al.
(författare)
-
Screening for genetic mutations
- 1996
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 380:6571, s. 207-
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 23. |
|
|
| 24. |
- Chen, Richard Z, et al.
(författare)
-
DNA hypomethylation leads to elevated mutation rates
- 1998
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 395:6697, s. 89-93
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide demethylation has been suggested to be a step in carcinogenesis. Evidence for this notion comes from the frequently observed global DNA hypomethylation in tumour cells, and from a recent study suggesting that defects in DNA methylation might contribute to the genomic instability of some colorectal tumour cell lines. DNA hypomethylation has also been associated with abnormal chromosomal structures, as observed in cells from patients with ICF (Immunodeficiency, Centromeric instability and Facial abnormalities) syndrome and in cells treated with the demethylating agent 5-azadeoxycytidine. Here we report that murine embryonic stem cells nullizygous for the major DNA methyltransferase (Dnmt1) gene exhibited significantly elevated mutation rates at both the endogenous hypoxanthine phosphoribosyltransferase (Hprt) gene and an integrated viral thymidine kinase (tk) transgene. Gene deletions were the predominant mutations at both loci. The major cause of the observed tk deletions was either mitotic recombination or chromosomal loss accompanied by duplication of the remaining chromosome. Our results imply an important role for mammalian DNA methylation in maintaining genome stability.
|
|
| 25. |
- Deliagina, TG, et al.
(författare)
-
Control of spatial orientation in a mollusc
- 1998
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 393:6681, s. 172-175
-
Tidskriftsartikel (refereegranskat)
|
|
| 26. |
- Dujon, B, et al.
(författare)
-
The nucleotide sequence of Saccharomyces cerevisiae chromosome XV
- 1997
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 387:6632, s. 98-102
-
Tidskriftsartikel (refereegranskat)abstract
- Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered(1). It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped(2). However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II (refs 3-5). The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.
|
|
| 27. |
- Dunham, I, et al.
(författare)
-
The DNA sequence of human chromosome 22
- 1999
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 402:6761, s. 489-495
-
Tidskriftsartikel (refereegranskat)
|
|
| 28. |
- Eghbali, M, et al.
(författare)
-
Hippocampal GABA(A) channel conductance increased by diazepam
- 1997
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 388:6637, s. 71-75
-
Tidskriftsartikel (refereegranskat)abstract
- Benzodiazepines, which are widely used clinically for relief of anxiety and for sedation, are thought to enhance synaptic inhibition in the central nervous system by increasing the open probability of chloride channels activated by the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Here we show that the benzodiazepine diazepam can also increase the conductance of GABAA channels activated by low concentrations of GABA (0.5 or 5 microM) in rat cultured hippocampal neurons. Before exposure to diazepam, chloride channels activated by GABA had conductances of 8 to 53pS. Diazepam caused a concentration-dependent and reversible increase in the conductance of these channels towards a maximum conductance of 70-80 pS and the effect was as great as 7-fold in channels of lowest initial conductance. Increasing the conductance of GABAA channels tonically activated by low ambient concentrations of GABA in the extracellular environment may be an important way in which these drugs depress excitation in the central nervous system. That any drug has such a large effect on single channel conductance has not been reported previously and has implications for models of channel structure and conductance.
|
|
| 29. |
- Egholm, M., et al.
(författare)
-
PNA HYBRIDIZES TO COMPLEMENTARY OLIGONUCLEOTIDES OBEYING THE WATSON-CRICK HYDROGEN-BONDING RULES
- 1993
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 365:6446, s. 566-568
-
Tidskriftsartikel (refereegranskat)abstract
- DNA ANALOGUES are currently being intensely investigated owing to their potential as gene-targeted drugs1-3. Furthermore, their properties and interaction with DNA and RNA could provide a better understanding of the structural features of natural DNA that determine its unique chemical, biological and genetic properties3,4. We recently designed a DNA analogue, PNA, in which the backbone is structurally homomorphous with the deoxyribose backbone and consists of N-(2-aminoethyl)glycine units to which the nucleobases are attached5-9. We showed that PNA oligomers containing solely thymine and cytosine can hybridize to complementary oligonucleotides, presumably by forming Watson-Crick-Hoogsteen (PNA)2-DNA triplexes, which are much more stable than the corresponding DNA-DNA duplexes5-7, and bind to double-stranded DNA by strand displacement5,8. We report here that PNA containing all four natural nucleobases hybridizes to complementary oligonucleotides obeying the Watson-Crick base-pairing rules, and thus is a true DNA mimic in terms of base-pair recognition.
|
|
| 30. |
- Elming, Sten-Åke
(författare)
-
Evidence for early Proterozoic plate tectonics from seismic reflection profiles in the Baltic Shield
- 1990
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 348, s. 34-38
-
Tidskriftsartikel (refereegranskat)abstract
- Plate tectonics provides the linking framework for all tectonic and magmatic activity seen today, but it is not known when plate tectonics first developed on Earth. New deep seismic reflection and coincident refraction profiles across an exposed, 1.89-Gyr-old volcanic arc complex show a 10-km-thick offset in the Moho and bivergent reflectors in the crust, which were most probably created by plate convergence, subduction and accretion during the Early Proterozoic. Hence, plate tectonic models seem to be applicable for at least the second half of Earth's history.
|
|
