An integrated molecular cytogenetic map of Cucumis sativus L. chromosome 2

<p>Abstract</p> <p>Background</p> <p>Integration of molecular, genetic and cytological maps is still a challenge for most plant species. Recent progress in molecular and cytogenetic studies created a basis for developing integrated maps in cucumber (<it>Cucumis sativus </it>L.).</p> <p>Results</p> <p>In this study, eleven fosmid clones and three plasmids containing 45S rDNA, the centromeric satellite repeat Type III and the pericentriomeric repeat CsRP1 sequences respectively were hybridized to cucumber metaphase chromosomes to assign their cytological location on chromosome 2. Moreover, an integrated molecular cytogenetic map of cucumber chromosomes 2 was constructed by fluorescence <it>in situ </it>hybridization (FISH) mapping of 11 fosmid clones together with the cucumber centromere-specific Type III sequence on meiotic pachytene chromosomes. The cytogenetic map was fully integrated with genetic linkage map since each fosmid clone was anchored by a genetically mapped simple sequence repeat marker (SSR). The relationship between the genetic and physical distances along chromosome was analyzed.</p> <p>Conclusions</p> <p>Recombination was not evenly distributed along the physical length of chromosome 2. Suppression of recombination was found in centromeric and pericentromeric regions. Our results also indicated that the molecular markers composing the linkage map for chromosome 2 provided excellent coverage of the chromosome.</p

1,4-Diazo­niabicyclo­[2.2.2]octane bis­(2,4,6-trinitro­phenolate)

In the title compound, C6H14N2 2+·2C6H2N3O7 −, the cation possesses crystallographically imposed twofold rotation symmetry. In the crystal structure, the cation and anions are linked into a trimeric aggregate by inter­molecular N—H⋯O hydrogen bonds. The trimeric units are further connected by π–π inter­actions [centroid–centroid distances = 3.507 (2)–3.660 (3) Å], forming layers parallel to the bc plane

Antiferromagnetic semiconductor Eu3Sn2P4 with Sn–Sn dimer and crown-wrapped Eu

A novel antiferromagnetic semiconductor, Eu3Sn2P4, has been discovered. Single crystals of Eu3Sn2P4 were prepared using the Sn self-flux method. The crystal structure determined by single crystal X-ray diffraction shows that Eu3Sn2P4 crystallizes in the orthorhombic structure with the space group Cmca (Pearson Symbol, oP216). Six Sn–Sn dimers connected by P atoms form a Sn12P24 crown-shaped cluster with a Eu atom located in the center. Magnetization measurements indicate that the system orders antiferromagnetically below a TN ∼14 K at a low field and undergoes a metamagnetic transition at a high field when T \u3c TN. The effective magnetic moment is 7.41(3) μB per Eu, corresponding to Eu2+. The electric resistivity reveals a non-monotonic temperature dependence with non-metallic behavior below ∼60 K, consistent with the band structure calculations. By fitting the data using the thermally activated resistivity formula, we estimate the energy gap to be ∼0.14 eV. Below TN, the resistivity tends to saturate, suggesting the reduction of charge-spin scattering