Germline-restricted chromosome (GRC) is widespread among songbirds

An unusual supernumerary chromosome has been reported for two related avian species, the zebra and Bengalese finches. This large, germline-restricted chromosome (GRC) is eliminated from somatic cells and spermatids and transmitted via oocytes only. Its origin, distribution among avian lineages, and function were mostly unknown so far. Using immunolocalization of key meiotic proteins, we found that GRCs of varying size and genetic content are present in all 16 songbird species investigated and absent from germline genomes of all eight examined bird species from other avian orders. Results of fluorescent in situ hybridization of microdissected GRC probes and their sequencing indicate that GRCs show little homology between songbird species and contain a variety of repetitive elements and unique sequences with paralogs in the somatic genome. Our data suggest that the GRC evolved in the common ancestor of all songbirds and underwent significant changes in the extant descendant lineages

VISUALIZATION OF CHROMOSOME-SPECIFIC DNA SEQUENCES BY FLUORESCENCE IN SITU HYBRIDIZATION OF MICRODISSECTION DNA PROBES WITH METAPHASE CHROMOSOMES

Presently, suppression of repetitive DNAsequences (chromosomal in situ suppression hybridization, СISS-hybridization) is used to improve the results of fluorescence in situ hybridization (FISH). However, in some cases the suppression cannot be performed, because sufficient amounts of DNAof some species are not available. This article presents a new approach, which allows visualization of a signal from chromosome-specific DNAsequences by means of computer-assisted analysis of FISH images

Pd/CeO2-SnO2 catalysts with varying tin content: Promotion of catalytic properties and structure modification

1%Pd/CeO2-SnO2 catalysts with varying Ce/Sn ratio were synthesized by counter-precipitation followed by calcination in a wide temperature range. The catalysts with Ce/Sn < 3/1 possess high thermal stability after calcination up to 1000 ◦C while maintaining low-temperature activity in CO oxidation. The PdOx clusters serving as active centers in CO oxidation are modified by Sn upon calcination. High tin content (Ce/Sn = 1/3) provides the activity of the catalysts in CH4 oxidation due to stabilization of PdO nanoparticles in the form of core@shell PdO@(CeO2 + SnO2) structures. Formation of the nanoheterophase structure upon calcination plays a key role in the stabilization of Pd-active centers of different types

Germline-restricted chromosome (GRC) in the sand martin and the pale martin (Hirundinidae, Aves): synapsis, recombination and copy number variation

All songbirds studied to date have an additional Germline Restricted Chromosome (GRC), which is no

[NiEn₃](MoO₄)_0.5(WO₄)_0.5 Co-Crystals as Single-Source Precursors for Ternary Refractory Ni–Mo–W Alloys

The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown