Vol 50, No 3 (2019)

The phenomenon of scaling, i.e., preserving the proportions of the embryo’s spatial pattern in dependence on its overall size, is the most prominent feature of the embryonic morphogenetic fields. Up to now, attempts to understand the mechanisms of scaling have been limited to the creation and analysis of the behavior of theoretical models that, to some extent, reproduce this phenomenon in silico. Only recently, when creating such models, scientists began to use experimental data on specific genes and their products (secreted proteins), which were identified during the study of various molecular mechanisms in embryogenesis. However, no approaches for the targeted identification of genes and proteins that are directly responsible for the embryonic scaling have been described in the literature so far. Developing such approaches and putting them into practice is an important task for future research. In this work, the main current publications on the problem of embryonic scaling and possible approaches to studying the mechanisms of this phenomenon are reviewed.

The results of meiosis studies during microsporogenesis in Siberian spruce (Picea obovata Ledeb.) in the forest ecosystems of the south of Central Siberia are presented. Meiosis features and different types of irregularities were detected. The features of male organ development show a high level of the Siberian spruce’s adaptation to the extreme climate of Siberia.

The effect of a number of phytohormones (IAA, ABA, and cytokinines) on the induction of in vitro somatic embryogenesis in callus cultures of wheat, cultivar Bashkirskaya 26, barley, cultivar Steptoe, and its ABA-deficient mutant AZ34 has been studied. It was shown that the ability or inability for somatic embryogenesis in callus tissue of both wheat and barley is determined by the IAA : ABA ratio. However, the level of cytokinines was similar in both embryogenic and nonembryogenic calli of each object studied. The analysis of callus tissue of the ABA-deficient mutant AZ34 revealed the stimulating role of ABA not only in the induction of somatic embryogenesis but also in the formation of normal embryos.

We studied the distribution of the main astrocyte markers (glutamine synthetase, glial fibrillary acidic protein, connexin 43) in the tanycytes of the third ventricle during postnatal development. Using immunohistochemical methods, we analyzed the brain sections of Wistar rats at each of the following postnatal ages: day 7 (n = 4), day 30 (n = 4), 4–6 months (n = 8), and 20 months (n = 4). It was found that the tanycytes undergo cytochemical and structural changes during postnatal development and aging. Tanycyte differentiation in the lining of the third ventricle occurs in the first postnatal week. The protein profile typical of adult rat tanycytes is formed during the first month of postnatal development. The cytochemical profile of tanycytes does not change with age, but the tanycyte processes are reorganized. The data will help to establish the role of studied proteins in the development, formation, and aging of tanycytes in the third ventricle.

The development of diverse tissues may be determined by cell fate at the level of cell lineage, especially for hypodermal (Hyp) and body muscle (BM) development in C. elegans. Here, we focused on hypodermal as well as body muscle development in C. elegans and performed a comparative genome study to explore the gene expression patterns and lineage specific regulatory mechanisms by re-mining the existing treasury. The approach of gene set enrichment analysis on related gene expression profiles was also integrated to mine the significantly associated pathways with tissue-specific transcription factors (TFs) regulation. As a result, we have identified different gene expression patterns as well as some of overlapping and specific genes of each lineage between Hyp and BM development. Furthermore, there were some specific regulatory modules identified for 3 TFs, including 5 pathways for HND-1 such as Hedgehog signaling pathway, 11 pathways for ELT-1 such as Calcium signaling pathway, as well as 23 pathways for NHR-25 such as Jak-STAT signaling pathway and some of metabolic pathways. In conclusion, the identification of specific genes and biological pathways by our comparative transcriptomic study may help us better understand the genetic mechanisms between hypodermal and body muscle development in C. elegans.