New insights into chromomere organization provided by lampbrush chromosome microdissection and high-throughput sequencing

Giant lampbrush chromosomes (LBCs) typical for growing oocytes of various animal species are characterized by a specific chromomere-loop appearance and massive transcription. Chromomeres represent universal units of chromatin packaging at LBC stage. While quite good progress has been made in investigation of LBCs structure and function, chromomere organization still remains poorly understood. To extend our knowledge on chromomere organization, we applied microdissection to chicken LBCs. In particular, 31 and 5 individual chromomeres were dissected one by one along the macrochromosome 4 and one microchromosome, respectively. The data on genomic context of individual chromomeres was obtained by high-throughput sequencing of the corresponding chromomere DNA. Alignment of adjacent chromomeres to chicken genome assembly provided information on chromomeres size and genomic boarders, indicating that prominent marker chromomeres are about 4–5 Mb in size, while common chromomeres of 1.5–3.5 Mb. Analysis of genomic features showed that the majority of chromomere-loop complexes combine gene-dense and gene-poor regions, while massive loopless DAPI-positive chromomeres lack genes and are remarkably enriched with different repetitive elements. Finally, dissected LBC chromomeres were compared with chromatin domains (topologically associated domains [TADs] and A/B-compartments), earlier identified by Hi-C technique in interphase nucleus of chicken embryonic fibroblasts. Generally, the results obtained suggest that chromomeres of LBCs do not correspond unambiguously to any type of well-established spatial domains of interphase nucleus in chicken somatic cells

Connectors With Derivative Comparative Prepositions in the Works of the Russian Literature of the 19th-20th Centuries

In the article on the material of art works by Russian writers of XIX–XX centuries the author studies the use of connectors multi-word combinations, which are composed of prepositional-case phrases with derivative comparative prepositions that connect the parts of complex sentences. Monitoring the functioning of derivative prepositions allows us to assert that in recent years the derivatives prepositions often lose their direct lexical meaning. Becoming the syntactic words, they can form connectors. The article aims to show that the connectors which have appeared in the business, scientific-technical, newspaper and journalistic style, gradually penetrate into fiction texts. The article presents fragments of literary texts that illustrate the gradual formation of the connectors in the art style of language during the 19th-20th centuries. It is noted here that in the XX century, the use of connectors with prepositional-case phrases with derivatives comparative prepositions becomes more frequency than in previous periods. The authors emphasize that the increase in their number, likely leads to expansion of the contexts in which they can be used. The author concluded on the basis of this analysis that the connectors remain poorly understood while they are relevant syntactic means in the modern Russian language