| 1. |
- Los, Marek Jan, et al.
(författare)
-
Requirement of an Ice/Ced-3 Protease for Fas/Apo-1-Mediated Apoptosis
- 1995
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 375:6526, s. 81-83
-
Tidskriftsartikel (refereegranskat)abstract
- THE Fas/APO-1 receptor is one of the major regulators of apoptosis(1-7). We report here that Fas/APO-1-mediated apoptosis requires the activation of a new class of cysteine proteases, including interleukin-1 beta-converting enzyme (ICE)(8-10) which are homologous to the product of the Caenorhabditis elegans cell-death gene ced-3 (refs 11, 12). Triggering of Fas/APO-1 rapidly stimulated the proteolytic activity of ICE. Overexpression of ICE, achieved by electroporation and microinjection, strongly potentiated Fas/APO-1-mediated cell death. In addition, inhibition of ICE activity by protease inhibitors, as well as by transient expression of the pox virus-derived serpin inhibitor CrmA or an antisense ICE construct, substantially suppressed Fas/APO-1-triggered cell death. We conclude that activation of ICE or an ICE-related protease is a critical event in Fas/APO-1-mediated cell death.
|
|
| 2. |
- Björn, Lars Olof
(författare)
-
Origins of photosynthesis
- 1995
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 376:6535, s. 25-26
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
- 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)
|
|
| 4. |
- 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.
|
|
| 5. |
|
|
| 6. |
- Näsholm, Torgny, et al.
(författare)
-
Boreal forest plants take up organic nitrogen
- 1998
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 392:6679, s. 914-916
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Plant growth in the boreal forest, the largest terrestrial biome, is generally limited by the availability of nitrogen. The presumed cause of this limitation is slow mineralization of soil organic nitrogen1,2. Here we demonstrate, to our knowledge for the first time, the uptake of organic nitrogen in the field by the trees Pinus sylvestris and Picea abies, the dwarf shrub Vaccinium myrtillus and the grass Deschampsia flexuosa. These results show that these plants, irrespective of their different types of root–fungal associations (mycorrhiza), bypass nitrogen mineralization. A trace of the amino acid glycine, labelled with the stable isotopes 13C and 15N, was injected into the organic (mor) layer of an old successional boreal coniferous forest. Ratios of 13C:15N in the roots showed that at least 91, 64 and 42% of the nitrogen from the absorbed glycine was taken up in intact glycine by the dwarf shrub, the grass and the trees, respectively. Rates of glycine uptake were similar to those of 15N-ammonium. Our data indicate that organic nitrogen is important for these different plants, even when they are competing with each other and with non-symbiotic microorganisms. This has major implications for our understanding of the effects of nitrogen deposition, global warming and intensified forestry.
|
|
| 7. |
- Sheldon, B C, et al.
(författare)
-
Ultraviolet colour variation influences blue tit sex ratios
- 1999
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 402, s. 874-877
-
Tidskriftsartikel (refereegranskat)abstract
- Brilliant blue and violet structural colours are common plumage ornaments in birds, but their signalling functions are poorly understood. This may be because birds also communicate in ultraviolet (UV-A) wavelengths (320–400 nm) invisible to humans, but a strong spectral component of many structural colours. From a wild population of blue tits—Parus caeruleus, sexually dimorphic primarily in the ultraviolet —we report experimental evidence that females skew the sex ratio of their offspring in response to the ultraviolet plumage ornamentation of their mates. Masking male ultraviolet reflectance reversed a positive correlation between reflectance and brood sex ratio observed in control pairs, demonstrating a causal effect of male ultraviolet ornamentation on offspring sex ratio. Ultraviolet reflectance also predicted male survival to the following breeding season, suggesting that it serves as a viability indicator. When taken together with ecological effects (laying date, nesting area), our experiments reveal that an unexpected amount of control exists over the primary sex ratio in birds, suggesting that chromosomal sex determination may not constrain the sex ratios of multiparous vertebrates.
|
|
| 8. |
- von Schantz, Torbjörn, et al.
(författare)
-
Genetics of long-spurred pheasants - Reply
- 1990
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 343:6259, s. 600-600
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract is not available
|
|
| 9. |
- Wittung, Pernilla, 1968, et al.
(författare)
-
DNA-LIKE DOUBLE HELIX FORMED BY PEPTIDE NUCLEIC-ACID
- 1994
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 368:6471, s. 561-563
-
Tidskriftsartikel (refereegranskat)abstract
- ALTHOUGH the importance of the nucleobases in the DNA double helix is well understood, the evolutionary significance of the deoxyribose phosphate backbone and the contribution of this chemical entity to the overall helical structure and stability of the double helix is not so clear. Peptide nucleic acid (PNA)1-7 is a DNA analogue with a backbone consisting of N-(2-aminoethyl)glycine units (Fig. 1) which has been shown to mimic DNA in forming Watson-Crick complementary duplexes with normal DNA7. Using circular dichroism spectroscopy we show here that two complementary PNA strands can hybridize to one another to form a helical duplex. There is a seeding of preferred chirality which is induced by the presence of an L- (or D-) lysine residue attached at the carboxy terminus of the PNA strand. These results indicate that a (deoxy)ribose phosphate backbone is not an essential requirement for the formation of double helical DNA-like structures in solution.
|
|
| 10. |
- Andersson, Siv GE, et al.
(författare)
-
The genome sequence of Rickettsia prowazekii and the origin of mitochondria
- 1998
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 396:6707, s. 133-140
-
Tidskriftsartikel (refereegranskat)abstract
- We describe here the complete genome sequence (1,111,523 base pairs) of the obligate intracellular parasite Rickettsia prowazekii, the causative agent of epidemic typhus. This genome contains 834 protein-coding genes. The functional profiles of these genes show similarities to those of mitochondrial genes: no genes required for anaerobic glycolysis are found in either R. prowazekii or mitochondrial genomes, but a complete set of genes encoding components of the tricarboxylic acid cycle and the respiratory-chain complex is found in R. prowazekii. In effect, ATP production in Rickettsia is the same as that in mitochondria. Many genes involved in the biosynthesis and regulation of biosynthesis of amino acids and nucleosides in free-living bacteria are absent from R. prowazekii and mitochondria. Such genes seem to have been replaced by homologues in the nuclear (host) genome. The R. prowazekii genome contains the highest proportion of non-coding DNA (24%) detected so far in a microbial genome. Such non-coding sequences may be degraded remnants of 'neutralized' genes that await elimination from the genome. Phylogenetic analyses indicate that R. prowazekii is more closely related to mitochondria than is any other microbe studied so far.
|
|
