H2O2 exposure causes oxidative stress, which plays a role in oocyte aging. Folic acid (FA), which is regarded as an antioxidant, can effectively scavenge oxidising free radicals. MicroRNAs (miRNAs) play an important role in regulating gene expression during oocyte development and maturation and may be involved in the H2O2-exposure-induced oxidative stress in oocytes. In the present study, we explored if FA protects oocytes from reactive oxygen species (ROS) in vitro and the role of microRNAs (miRNAs) in this process. We compared the oocyte quality, ROS levels, mitochondrial membrane potential (MMP), 2 pronucleus (2PN) ratios, embryonic developmental potential, and miRNA expression in fresh mouse oocytes, H2O2-treated mouse oocytes, and FA and H2O2-treated mouse oocytes. The results demonstrated that FA could significantly reduce the ROS levels and fragments of H2O2-treated mouse oocytes and increase superoxide dismutase (SOD) levels, alleviating the H2O2-mediated oocyte 2PN ratio decreasing. H2O2-treated oocytes showed increased miR-10a expression, whereas FA treatment decreased miR-10a expression. In conclusion, miR-10a plays a vital role in the prevention of oxidative stress in oocytes.

Developmental delay at the blastocyst stage or embryonal diapause is characteristic for many animal species. This review describes the types of embryonic diapause, the hormonal and molecular mechanisms of its regulation, and specific features of this reproductive phenomenon in different taxa. Special emphasis is made on the possibility of applying modern reproductive technologies to diapausing mammalian species.

The present study examined the distribution of the gap junction protein connexin-43 in the dorsal root ganglion (DRG) cells at different stages of the rat prenatal development. Using immunohistochemical methods, we established that the first connexin-43-containing structures are identified in the developing DRG precursor cells starting from the 13th day of prenatal development. At the later stages of development, connexin-43 is present only in satellite glial cells. Sensory neurons do not contain protein. It was shown for the first time that connexin-43 is expressed in the boundary cap cells of the rat spinal cord dorsal root, starting from the 14th day of embryonic development until birth. This fact may indicate the participation of connexin-43 in the processes of establishing connections between the central and peripheral nervous systems during development.

The neural crest of the human embryo is a structure that has been studied for a long time. However, the information about this structure is not well systematized. The terminology, structure, and derivatives of the neural crest, as well as the directions of differentiation of its cells, are the subject of many controversies. This review analyses data obtained from classical and modern morphological studies of the neural crest, focusing on the development, structure, and derivatives of the neural crest of the human embryo. The review covers the history of discovery, nomenclature, and phylogeny of the neural crest; its formation in humans; and a description of the main parts of the cranial and spinal parts of the neural crest. It also lists the cells and tissues of the final organism that develop from the neural crest. The review aimed at analyzing the current literature on the morphology of the human neural crest and systematizing the data on the structure of the human neural crest and its derivatives.

Fibrodysplasia ossificans progressiva (FOP) is a severe genetic disease caused by mutations in the ACVR1 gene for which there is currently no effective therapy. Therefore, obtaining iPSCs for further modeling and development of treatment methods, including gene therapy, can be very promising. The authors herein describe the generation of the induced pluripotent stem cell (iPSCs) line RCMGi014-A from urinary sediment cells of a patient with clinically expressed and genetically proven (ACVR1:c.6176G>A) FOP. These iPSCs proliferate in dense monolayer cell colonies, have a normal karyotype (46,XY), express pluripotency markers (OCT4, SOX2, TRA-1-60, SSEA-4), and show the ability to differentiate into three germ layers, which confirms their pluripotent status.

The life cycle of the common ancestor of Metazoa is a widely debated topic in EvoDevo. This is intimately linked to a number of questions, such as how the larva appeared in the metazoan life cycle and which larval form can be considered ancestral. To approach these questions, we can analyse the life cycles and larval forms of Cnidaria, the basal metazoans that form a sister group to the Bilateria. Almost all cnidarians have a pelagic larva in their life cycle. These larvae are commonly referred to as “planula,” with few exceptions. The planula is a ciliated lecithotrophic larva with epithelial ectoderm and endoderm, a gastric cavity, and an elongated body. The review examines whether the larvae of various Cnidaria fit this description and explores which larval form is ancestral for different cnidarian taxa. It also highlights the enormous diversity of cnidarian larvae, which is still underestimated, and infers the relationship between the evolution of life cycles, reproductive patterns, and larval forms in various phylogenetic groups of cnidarians.

The Drosophila toothrin gene is related to the conserved d4 family of genes that encode specific transcription factors. In previous works, we investigated the effect of tth gene overexpression and characterized the specific pattern of its expression in the nervous system, but mutations in the tth gene have not yet been found. Null mutants are essential for analyzing gene function and screening of partner genes. Here we report the generation of the first tth gene knockout in Drosophila using a homologous recombination technique.

Atavisms have attracted people’s attention for a long time. First, atavisms excited their imagination and created fertile ground for myths and superstitions. With the development of science, atavisms became the subject of investigation, which soon provided evidence to support evolutionary theory. However, at the molecular level, the formation of atavisms remained insufficiently understood. Recent progress in comparative genomics and molecular developmental biology has helped in understanding the processes underlying the formation of one of the human atavisms: the vestigial tail.

Maintaining an optimal acid-base balance of the organism has a pivotal role in the regulation of metabolism. It is provided by the functioning of endogenous pH-sensors, the molecules with abilities to change their activity with the changes in the pH of the medium. Receptor tyrosine kinase IRR (insulin receptor-related receptor) is an alkaline pH sensor that is activated when the pH of the extracellular medium rises above 7.9. The expression of IRR is specific; the receptor is found in some organs, in certain types of cells. It has been established that the IRR receptor is involved in the excretion of bicarbonate by kidneys. The mechanism of action and function of the IRR receptor as an alkaline pH sensor in other organs is not understood yet. To reveal the role of the IRR receptor in the embryogenesis, we carried out experiments to evaluate the development of preimplantation embryos of wild-type and insrr knockout mice using the MEA (Mouse Embryo Assay) test. The development was assessed using the blastocyst yield index, the percentage of blastocyst formation from the total number of obtained zygotes. The yield of blastocysts in knockout animals was lower than in wild-type animals; it was 6.7% of the total number of extracted cells for knockout animals and 43.8% for wild-type animals. The number of obtained zygotes in case of wild-type and insrr knockout mice also differed. The average number of extracted zygotes from one female was 18.9 zygotes for wild-type mice and 11.8 zygotes for insrr knockout mice. Our results reveal a possible role for the receptor tyrosine kinase IRR in the development of preimplantation embryos.

Serotonin (5-HT) is known as a substance with a wide range of physiological effects. At the same time, its presence in the cells of the developing embryo is already shown from the earliest stages of development. However, the effect of increasing the level of intracellular serotonin on the processes of cleavage in representatives of Spiralia has not been studied in detail. For the first time, we investigated changes in the pattern of spiral cleavage in the freshwater mollusk Lymnaea stagnalis after incubation of eggs (during 24 h, from the stage of zygote/2 blastomeres) in a solution with serotonin—5-HTP precursor. During cleavage, the mutual arrangement of blastomeres was disrupted in all experimental embryos, starting from the apical rosette stage until the early gastrula. The delay in cytotomy of the blastomeres of the A and C quadrants led to the displacement of blastomeres in all quadrants, including B and D, as a result of which the blastomeres acquired contacts that are unusual for them normally. Subsequently, 80% of the embryos of the experimental group had irreversible impairment of gastrulation and the formation of exogastrula. In embryos that successfully passed gastrulation, malformations of the eyes and shell were observed in 10–15% of cases. Our results show that an increase in the level of intracellular serotonin leads to a disturbance of the mutual arrangement of blastomeres in a representative of Spiralia and may also lead to disorders of further development.