Establishment and Identification of Cytoplasmic Male Sterility in Brassica napus by Intergeneric Somatic Hybridization

Exploitation of novel cytoplasmic male sterility(CMS)is a main approach for widening the cytoplasmic genetic background of hybrid oilseed rape and avoiding epidemic risk in oilseed rape production.In this study,symmetric somatic hybrids between Brassicanapus var.Zhongshuang4 and Sinapis arvensis(Yeyou18)were produced by protoplast fusion.Two of the six established hybrids were male sterile showing trace or no pollen release upon flowering with non-or slightly extended stamens.Using Zhongshuang4 as a recurrent parent to pollinate the male sterile plants,the ratio of male sterile plants increased with the number of backcrosses.As early as in BC3 generation,most of the sterile families had nearly 100%sterile plants.Up to BC4 generation,the male sterility became stable and no fertility segregation was observed.All F1 progenies from tested crosses using restorer and maintainer lines of Polima CMS were 100%sterile,indicating that the established CMS by somatic hybridization is different from Polima CMS.The origin of the cytoplasm and potential use of this hovel CMS in oilseed rape breeding were discussed.Key wotds:Oilseed rape,Protoplast fusion,Cytoplasmic male sterility,Sinapis arvensis     

Stability of Ferropericlase in the Lower Mantle

We have heated ferropericlases (Mg(0.60)Fe(0.40))O and (Mg(0.50)Fe(0.50))O to temperatures of 1000 kelvin at pressures of 86 gigapascals, simulating the stability of the solid solution at physical conditions relevant to Earth's lower mantle. The in situ x-ray study of the externally heated samples in a Mao-Bell-type diamond anvil cell shows that ferropericlase may dissociate into magnesium-rich and iron-rich oxide components. The result is important because the decomposition of ferropericlase into lighter and heavier phases will cause dynamic effects that could lead to mantle heterogeneity.     

Role of brain insulin receptor in control of body weight and reproduction

Insulin receptors (IRs) and insulin signaling proteins are widely distributed throughout the central nervous system (CNS). To study the physiological role of insulin signaling in the brain, we created mice with a neuron-specific disruption of the IR gene (NIRKO mice). Inactivation of the IR had no impact on brain development or neuronal survival. However, female NIRKO mice showed increased food intake, and both male and female mice developed diet-sensitive obesity with increases in body fat and plasma leptin levels, mild insulin resistance, elevated plasma insulin levels, and hypertriglyceridemia. NIRKO mice also exhibited impaired spermatogenesis and ovarian follicle maturation because of hypothalamic dysregulation of luteinizing hormone. Thus, IR signaling in the CNS plays an important role in regulation of energy disposal, fuel metabolism, and reproduction.     

Molecular and neuronal substrate for the selective attenuation of anxiety

Benzodiazepine tranquilizers are used in the treatment of anxiety disorders. To identify the molecular and neuronal target mediating the anxiolytic action of benzodiazepines, we generated and analyzed two mouse lines in which the alpha2 or alpha3 GABAA (gamma-aminobutyric acid type A) receptors, respectively, were rendered insensitive to diazepam by a knock-in point mutation. The anxiolytic action of diazepam was absent in mice with the alpha2(H101R) point mutation but present in mice with the alpha3(H126R) point mutation. These findings indicate that the anxiolytic effect of benzodiazepine drugs is mediated by alpha2 GABAA receptors, which are largely expressed in the limbic system, but not by alpha3 GABAA receptors, which predominate in the reticular activating system.     

Structure of the polycrystalline zeolite catalyst IM-5 solved by enhanced charge flipping

Despite substantial advances in crystal structure determination methodology for polycrystalline materials, some problems have remained intractable. A case in point is the zeolite catalyst IM-5, whose structure has eluded determination for almost 10 years. Here we present a charge-flipping structure-solution algorithm, extended to facilitate the combined use of powder diffraction and electron microscopy data. With this algorithm, we have elucidated the complex structure of IM-5, with 24 topologically distinct silicon atoms and an unusual two-dimensional medium-pore channel system. This powerful approach to structure solution can be applied without modification to any type of polycrystalline material (e.g., catalysts, ceramics, pharmaceuticals, complex metal alloys) and is therefore pertinent to a diverse range of scientific disciplines.     

Shrinking Danish agriculture

Danish agriculture is facing a turning point. Centuries of struggle to increase arable land area as well as its productivity is about to be reversed, due to overproduction and environmental problems. Some land will probably be turned back to nature, and the use of chemicals in agriculture in general will be reduced, perhaps with a lower productivity and a better environment as a consequence. This paper mainly describes some of the political actions taken in Denmark to influence environmental-agricultural issues. First, however, some of the recently perceived environmental problems and over-production problems connected with Danish farming are outlined.