Geoff S. Baldwin, Nicholas J. Brooks, Rebecca E. Robson, Aaron Wynveen, Arach Goldar, Sergey Leikin, John M. Seddon, Alexei A. Kornyshev.
J. Phys. Chem. B, 112, 1060-1064 (2008) | doi:10.1021/jp7112297
The structure and biological function of the DNA double helix are based on interactions recognizing sequence complementarity between two single strands of DNA. A single DNA strand can also recognize the double helix sequence by binding in its groove and forming a triplex. We now find that sequence recognition occurs between intact DNA duplexes without any single-stranded elements as well. We have imaged a mixture of two fluorescently tagged, double helical DNA molecules that have identical nucleotide composition and length (50% GC; 294 base pairs) but different sequences. In electrolytic solution at minor osmotic stress, these DNAs form discrete liquid-crystalline aggregates (spherulites). We have observed spontaneous segregation of the two kinds of DNA within each spherulite, which reveals that nucleotide sequence recognition occurs between double helices separated by water in the absence of proteins, consistent with our earlier theoretical hypothesis. We thus report experimental evidence and discuss possible mechanisms for the recognition of homologous DNAs from a distance.# 二本鎖DNA同士が配列を認識するという報告
# 実に美容外科的な発想だな
# 実際、正直なところどうなの？実用に堪える紙は作れるの？
# ようやく開始ですか…
# もの凄い単純計算すればそういうことになるわな…
Michael A. Strauss.
Nature 451, 531-532 (2008) | doi:10.1038/451531a
L. Guzzo, M. Pierleoni, B. Meneux, E. Branchini, O. Le Fèvre, C. Marinoni, B. Garilli, J. Blaizot, G. De Lucia, A. Pollo, H. J. McCracken, D. Bottini, V. Le Brun, D. Maccagni, J. P. Picat, R. Scaramella, M. Scodeggio, L. Tresse, G. Vettolani, A. Zanichelli, C. Adami, S. Arnouts, S. Bardelli, M. Bolzonella, A. Bongiorno, A. Cappi, S. Charlot, P. Ciliegi, T. Contini, O. Cucciati, S. de la Torre, K. Dolag, S. Foucaud, P. Franzetti, I. Gavignaud, O. Ilbert, A. Iovino, F. Lamareille, B. Marano, A. Mazure, P. Memeo, R. Merighi, L. Moscardini, S. Paltani, R. Pellò, E. Perez-Montero, L. Pozzetti, M. Radovich, D. Vergani, G. Zamorani, E. Zucca.
Nature 451, 541-544 (2008) | doi:10.1038/nature06555
Observations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the equations of cosmic expansion, accounting for about 75 per cent of the total energy density in the Universe. The simplest option for this 'dark energy' corresponds to a 'cosmological constant', perhaps related to the quantum vacuum energy. Physically viable alternatives invoke either the presence of a scalar field with an evolving equation of state, or extensions of general relativity involving higher-order curvature terms or extra dimensions. Although they produce similar expansion rates, different models predict measurable differences in the growth rate of large-scale structure with cosmic time. A fingerprint of this growth is provided by coherent galaxy motions, which introduce a radial anisotropy in the clustering pattern reconstructed by galaxy redshift surveys. Here we report a measurement of this effect at a redshift of 0.8. Using a new survey of more than 10,000 faint galaxies, we measure the anisotropy parameter β= 0.70 ± 0.26, which corresponds to a growth rate of structure at that time of f = 0.91 ± 0.36. This is consistent with the standard cosmological-constant model with low matter density and flat geometry, although the error bars are still too large to distinguish among alternative origins for the accelerated expansion. The correct origin could be determined with a further factor-of-ten increase in the sampled volume at similar redshift.# 「dark energy」＝「暗黒エネルギー」…日本語にするとどうもちんけなSFっぽくなるなぁ
# まぁ、地上にまで達することはないとは思うんだが…
# それにしてもこの映像、よく撮ったな
