SHI family transcription factors regulate an interspecific barrier.

Pre-zygotic interspecies incompatibility in angiosperms is an important mechanism to prevent unfavourable hybrids between species. Here we report our identification of STIGMATIC PRIVACY 2 (SPRI2), a transcription factor that has a zinc-finger domain and regulates interspecies barriers in Arabidopsis thaliana, via genome-wide association study. Knockout analysis of SPRI2/SRS7 and its paralogue SPRI2-like/SRS5 demonstrated their necessity in rejecting male pollen from other species within female pistils. Additionally, they govern mRNA transcription of xylan O-acetyltransferases (TBL45 and TBL40) related to cell wall modification, alongside SPRI1, a pivotal transmembrane protein for interspecific pollen rejection. SPRI2/SRS7 is localized as condensed structures in the nucleus formed via liquid-liquid phase separation (LLPS), and a prion-like sequence in its amino-terminal region was found to be responsible for the formation of the condensates. The LLPS-regulated SPRI2/SRS7 discovered in this study may contribute to the establishment of interspecific reproductive barriers through the transcriptional regulation of cell wall modification genes and SPRI1.

Vibrational properties of noble gas endohedral fullerenes.

Analysis of IR and Raman spectra of Ar@C(60) and Kr@C(60) shows that the incorporation of noble gas atoms causes a blue shift of low energy vibrations, which have radial character, and a red shift of higher energy ones which have a tangential character movement. The mechanism of these phenomena is explained on the basis of ab initio numerical experiments with DFT and MP2 procedures. Methodological discussions are advanced, altogether with a scheme for the estimation of the van der Waals interaction between fullerene and noble gas, based on the frequency shifts.

Communication: The reason why +c ZnO surface is less stable than -c ZnO surface: first-principles calculation.

It has been experimentally shown that an O(-c)-polar ZnO surface is more stable than a Zn(+c)-polar surface in H(2) ambient. We applied first-principles calculations to investigating the polarity dependence on the stability at the electronic level. The calculations revealed that the -c surface terminated with H atom was stable maintaining a wurtzite structure, whereas the +c surface was unstable due to the change of coordination numbers of Zn at the topmost surface from four (wurtzite) to six (rock salt). This causes the generation of O(2) molecules, resulting in instability at the +c surface.

Separation of N2@C60 and N@C60.

We describe the HPLC separation and identification of N@C60 and N2@C60. These species were observed after eleven sequential HPLC separations. Their retention times are in the same range as those of the other noninteractive endohedral species of C60, such as noble gas endohedral C60. The separation factors of these endohedrals were evaluated by using a mixture of hexane/toluene as eluent. We note that this is the first evidence for the N2@C60 molecule existing in the form of endohedral C60 complex.