Evolutionary and developmental biology are among the most dynamically developing areas of modern biology. Both have a long and turbulent history, especially in Russia (USSR). However, any science develops thanks to the breakthrough research of individual scientists and scientific teams. In this paper, we briefly analyzed the main theoretical works of Leningrad State University professor G. P. Korotkova (1924–2009), who made a significant contribution to general biology at the end of the twentieth century. G. P. Korotkova is known for her pioneering work in the field of regeneration of invertebrate animals and, first of all, sponges, evolutionary and philosophical aspects of biology. In particular, her contribution to the theoretical aspects of regenerative biology, to the development of philosophical aspects of the problems of wholenessis considered. The principles of her original hypothesis of the origin and phase evolution of ontogenesis are briefly outlined, as well as her ideas regarding the theoretical aspects of the biology and organization of sponges (Porifera).
The blue king crab Paralithodes platypus (Brandt, 1851) is a widespread and abundant member of the family Lithodidae in the Pacific Ocean. However, its population size in the Sea of Japan is subject to strong fluctuations. Due to the low abundance of blue crab, its commercial fishery in the Sea of Japan has been prohibited since 2022. Therefore, the aim of the study was to evaluate the growth characteristics and growth potential of the blue king crab in the Sea of Japan relative to other aggregations of this species in the Sea of Okhotsk and the Bering Sea. The growth was studied according to the literature and our own data, which were collected on counting-trap surveys in the coastal regions of the Sea of Japan in 2011–2014. According to the Bertalanffy equation, male blue king crab in the Sea of Japan reach the carapace width CWinf = 193.5 mm, females – 162.1 mm. Comparison results of growth rate of the aggregation in the Sea of Japan showed significant differences with crabs off the Shantar Islands and eastern Sakhalin and did not note statistically significant differences in growth relative to aggregations in Shelikhov Bay and in the Bering Sea. Probably, first of all, such differences are the result of the complex influence of hydrological habitat conditions, food productivity of water areas, as well as competition, both interspecific and intraspecific.
The germes gene is a marker of germ plasm and primordial germ cells (PGC). It is described for the African clawed frog Xenopus laevis . Overexpression of its mutant form negatively affects the formation and migration of PGC. However, it was unknown until now how widely this gene is represented in animals of different phylogenetic groups. For this work, the authors performed bioinformatic analysis of genomic and transcriptome sequences of animals with germ plasm. We found out that the germes homologs are present only in representatives of the genera Xenopus and Hymenochirus of the family Pipidae (order Anura). The obtained results were confirmed by RT-PCR analysis of the expression of the germes orthologs in the ovaries of six representatives of different Anura families. Phylogenetic analysis of cloned sequences of the germes homologs suggests the appearance of this gene in the ancestors of Pipidae and its secondary loss in the genus Pseudohymenochirus . It is also shown that the amino acid sequences of the functional domains of the Germes protein are rather conservative.
The maternal effects that increase the adaptability of offspring are often caused by stressful conditions that persist in the environment. However, it is not clear where the threshold lies at which maternal effects cease to be adaptive for offspring and lead to developmental instability. One of the known environmental stressors is the unpredictable changes in environmental conditions. We aimed to test whether instability of the maternal environment lead to a decrease in developmental robustness in the offspring of the gastropod mollusk Lymnaea stagnalis . The laboratory population of snails was split into two groups. For the first group, conditions were maintained as stable as possible, with constant water exchange and excessive feeding. The second group was kept under unstable (stressful) conditions, with episodic feeding and water exchange. The unstable conditions alone did not affect the frequency of developmental anomalies in the offspring. Since serotonin is thought to play the role of the signaling molecule mediating the maternal effect in L. stagnalis , we exposed the embryos of both groups to the biochemical precursor of serotonin (5-HTP). After incubation in 5-HTP, the proportion of embryos with developmental anomalies was significantly higher for the offspring of mothers living in unstable conditions. We also demonstrated rich serotoninergic innervation of the hermaphroditic gland (ovotestis) and accumulation of serotonin in the cytoplasm of the forming oocytes, supporting the role of serotonin in the maternal signaling. Our experiments suggest that, accumulation of serotonin in the oocyte/zygote may exceed the adaptive level and increase the risk of malformations during embryonic development.
The subfornical organ (SFO) is one of the circumventricular organs (CVOs) of the mammalian nervous system responsible for maintaining the energy and water and sodium balance. Despite notable interest in the SFO and its physiological functions, the organization of individual populations of SFO cells, as well as their interactions, remain unclearly established. In this study, GABA and nitroxidergic systems of SFO using immunohistochemical (IHC) methods were examined. The brain of male Wistar rats at different stages of postnatal development—postnatal day 7 (P7), 14 (P14), and adult (4–6 months)—was examined. The obtained data allowed the authors to characterize changes in the activity of the GABA- and nitroxidergic systems of the SFO during development. In adult rats, three subpopulations of nitroxidergic cells, differing in the intensity of the reaction and tissue localization, can be distinguished. The revealed morphological heterogeneity of nitroxidergic cells in SFO may reflect their diverse functional status.
The evolutionary origin of segmentation remains a mystery. In arthropods, gene engrailed is recognized as one of the most important and conservative members of the segmentation developmental program. Orthologues of this gene have been identified in annelids, but their role is interpreted as contradictory, because their expression in some species precedes subdivision of the body into segments but it does not in others. The expression of engrailed in the nereid polychaete Alitta virens during metamorphosis and development of the first postlarval segments was studied herein. Our data support the possible involvement of this gene in the process of segment formation from the growth zone in A. virens . At the larval stages, engrailed is expressed in neuroectodermal cells, in the growth zone, and in metameric epidermal cell rows at the anterior boundary of each segment. Upon transition from the metatrochophore to the nectochaete stage, the circular expression domain in the growth zone expands and then resolves into two serial domains. Over time, the distance between these circular domains increases, indicating the growth of the first postlarval segment anlage. Formation of subsequent postlarval segments occurs in a similar way. Analyzing our results and literature data, we compared engrailed expression patterns in annelids and arthropods. Our work indicates an absence of conservation in patterning of sequentially developing segments from the growth zone in protostomes. We suggest that the anteroposterior axis elongation in A. virens occurs simultaneously with the specification of a new segment. These features differ from the known models of the growth zone and indicate the possibility that nereids have a specific mechanism of segmentation.
The pluripotent status of a cell in vivo is spatio-temporally regulated within embryogenesis and is determined by the processes of self-renewal, endless proliferation, and differentiation into all cell types of the body. Initially, the concept of pluripotency status was proposed for characterization of teratocarcinoma cells, and then this concept was applied to the embryonic cells of the preimplantation mouse embryo. Mouse and human pluripotent stem cells (PSCs) are formed during the preimplantation period and are present in the embryo until the beginning of gastrulation. The differentiation of the inner cell mass of the blastocyst (ICM) into a hypoblast and an epiblast, which develops into the embryo itself, is one of the main events in early mammalian development. Continuous and dynamic transformation of pluripotency states in development coincides with the morphogenetic processes that are involved in the formation and maturation of the epiblast. Thus, blastocyst ICM cells differ in epigenetic and transcription patterns from their daughter cells forming the peri/postimplantation epiblast. With the onset of gastrulation movements, the maturation of epiblast cells ends with their differentiation into cells of three germ layers. This review considers the historical aspects of the study of cell pluripotency, various sources of PSCs, and mechanisms and signaling pathways that support self-renewal and pluripotency in PSCs cultures. In addition, the authors summarize and conceptualize data on morphogenetic processes that are involved in the formation of naive ICM cells in vivo and the subsequent maturation of mouse and human epiblast cells associated with the transformation of their pluripotency states.
One of the most important events in the embryonic development of mammals is the division of the ectoderm into integumentary and neuroectoderm. Signaling cascades induced by growth factors and cytokines involved in these processes have been studied in detail in recent decades. At the same time, the contribution of extracellular matrix (ECM) to these differentiation lineages remains unknown for mammals, while the significance of ECM in this process has been shown for other model organisms. To assess the effect of ECM on the formation of ectodermal derivatives, we modeled the neural and epidermal differentiation of human induced pluripotent stem cells (iPSCs) using substrates consisting of various ECM molecules and also studied the involvement of one of the central links of the ECM signaling cascades, a transcriptional coactivator YAP1 in differentiation processes. Our results revealed the stimulatory effect of laminin 332 on the early stages of epidermal differentiation and of type I and III collagens on the induction of the glial fate of late neural differentiation.
Wood formation (xylogenesis) in trees depends on two main factors providing growth processes with assimilates and energy, photosynthesis and respiration. Temperature and precipitation affect photosynthesis and respiration and, consequently, growth processes in wood. The aim of our study was to characterise the relationship of growth processes (cambium activity and biomass deposition) in Pinus sylvestris L. (Scotch pine) trunks with crown photosynthetic activity and trunk respiration in years with contrasting summer-weather conditions. Formation of xylem and phloem cells, accumulation of cell wall biomass, photosynthetic productivity and trunk respiration were studied in P. sylvestris trees growing in Eastern Siberia (Russia). We estimated the number of cells in differentiation zones and morphological parameters of cells produced by cambium, determined cambium activity, accumulation of biomass in tracheid walls and their relationship with crown photosynthetic productivity and stem respiration costs at certain stages of annual ring wood formation. It turned out that cambium cell division towards xylem or phloem depends on the combination of temperature and precipitation in some periods of the season, as well as on the reaction of photosynthesis and respiration to these factors. Biomass accumulation had a bimodal character with maxima in June (early wood development) and predominantly in August (development of thick-walled late tracheids). This corresponded to an optimum combination of air temperature and humidity, providing sufficient assimilate influx and low respiration consumption. We also showed that cambial activity and biomass accumulation in the cell walls of annual wood rings depend on the cumulative effect of temperature and precipitation on photosynthesis and stem respiration during the growing season. Fluctuations in external factors changes the balance between the inflow of photoassimilates and their utilization. As a result, photoassimilates are utilised not only for synthesis of cell wall biomass, but also partially converted into reserve substances, particularly starch. Our study expands the understanding of plant development processes that lead to wood formation under the influence of external factors.
The review is devoted to the analysis and generalization of modern knowledge about the mechanisms underlying the ontogeny of the male gametophyte envelope. New and earlier data on exine development аre discussed, and recurrent phases in the development of exine of phylogenetically distant plant species are emphasized. Though exine formation has been shown to be dependent on plenty of genes, the reiteration of exine patterns in different plant species (e.g. columellate, granular, “white-lined” lamellae) suggests that these patterns are based on some non-biological principles of space-filling operations. However, mechanisms involved remained obscure until it became clear that the sequence of structures observed during exine development coincided with the sequence of self-assembling micellar mesophases. It was discovered later that another physical-chemical process—phase separation—participated in exine formation. To confirm that exine-like patterns are capable of generating in vitro by simple physical processes, and their formation does not require regulation at the genome level, some our and other authors’ in vitro experiments were undertaken; the data obtained are discussed. Several series of our new experiments on modeling exine development with mixtures of surface-active substances resulted in some patterns simulating the main types of natural exine. Transmission electron microscopy analysis of the samples has shown that patterns simulating the full range of exine types were obtained by joint action of phase separation and micellar self-assembly. The reconsideration and analysis of our and other authors’ morphogenetic and modeling data revealed that molecular-genetic mechanisms and physical forces work in tandem, with considerable input of physical processes.
Differentiation of induced pluripotent stem cells (iPSCs) from patients and healthy donors allows in vitro study of genetic disorders. The authors have previously reported a clinical case of recurrent pregnancy loss in a patient with skewed X-chromosome inactivation in peripheral blood lymphocytes, endometrium, and buccal epithelium. A 239 kb microdeletion at Xq24 that affected eight genes, including UBE2A , has been found. In this work, an iPSC line iTAF15Xsk4 was produced from the patient’s skin fibroblasts using nonintegrating episomal vectors. The iPSC line had a normal karyotype, expressed pluripotency markers, and expressed markers of all three germ layers upon differentiation in embryoid bodies. This cell line could be used for the UBE2A deficiency syndrome study.
Proteasomes, the most important participants in protein catabolism, maintain proteostasis and regulate cellular processes in ontogeny. Deviations in the functioning of proteasomes are associated with the development of various pathologies, including a number of oncological diseases. In this work, we studied changes in subunit gene expression and proteasome activity in laryngeal cancer tissue and epithelium of patients with chronic hyperplastic diseases of the larynx, which are considered obligate precancer. The activity of circulating proteasomes was also studied in the same groups of patients. The level of gene expression was assessed using quantitative reverse transcriptase followed by PCR in real time. A method for assessing chymotrypsin-like (CTL) and caspase-like (CL) activities of proteasomes has been modified for the analysis of small volumes of biopsy samples. An increase in the level of expression of the proteasome genes ( PSMB6 , PSMB7 , PSMB5 , and PSMB4 ) in the tissues of squamous cell carcinoma of the larynx was shown compared to pretumor samples. An increase in CTL and CL activities of intracellular proteasomes in the malignant epithelium of the larynx was also found in comparison with the conditionally normal tissue and with the epithelium of patients with chronic hyperplastic diseases of the larynx. An increase in chymotrypsin-like activity was observed in circulating proteasomes. ROC-analysis (Receiver operating characteristic) revealed the relationship between PSMB5 mRNA expression and CTL activity of tissue proteasomes with the development of laryngeal cancer in patients with chronic hyperplastic diseases of the larynx. In the future, it is possible to use these indicators to develop a method for predicting the transition of precancer of larynx to cancer.
Comparative and ecological aspects of the reorganizations of early development in the class Amphibia are analyzed. We used data on the developmental diversity in a number of families belonging to the orders Anura and Caudata, in which many species had lost their connection with the aquatic environment. Model representatives of the class Amphibia ( Ambystoma mexicanum , Rana temporaria , and Xenopus laevis ) have small eggs (no more than 2.5 mm in diameter). In these species, the slowdown in the rate of cell divisions and the loss of synchrony occur at the midblastula stage. However, phylogenetically basal amphibian species ( Ascaphus truei , Cryptobranchus alleganiensis ) are characterized by the large (4–6 mm in diameter) yolky eggs and a short series of synchronous blastomere divisions (the synchrony is already lost at the 8-cell stage of cleavage). They do not have a “midblastula transition,” which is characteristic of the above model species. On the other hand, many evolutionarily advanced non-model species of caudate and anuran amphibians (for example, Desmognathus fuscus , Gastrotheca riobambae , Philoria sphagnicolus ), as well as the basal species, are characterized by the large, yolk-rich eggs and the early loss of cell division synchrony. Phylogenetic analysis suggests that the cleavage pattern of the most extensively studied amphibians, the Mexican axolotl (Caudata) and the African clawed frog (Anura), represents a homoplasy. The midblastula transition, which is characteristic of these two species, might have evolved convergently in these two orders of amphibians as an embryonic adaptation to development in lentic water.
Serotonin is not only a neurotransmitter but also an important humoral regulator of various physiological processes outside the central nervous system. In the last decade, the concept of local serotonergic systems in peripheral organs, where serotonin realizes its effects via autocrine/paracrine mechanisms, has been under development. Such local systems have already been described in the pancreas, thymus, mammary gland, and bone marrow. We consider that a similar local serotonergic system is also characteristic of the adrenal glands. These paired organs are a key component of the mammalian endocrine system, providing a complex physiological response to stress. The adrenal glands consist of two parts distinct in origin and function—the cortex and medulla—while serotonin plays an important role in regulating hormone secretion in both of these structures. This review is aimed at analyzing the structure of the local serotonergic system in the adrenal gland as well as its role both in the regulation of adrenal functions in adult animals and in the formation of adrenals in embryogenesis. Analysis of the available data suggests that local serotonergic systems makes an organ susceptible to fluctuations in the level of serotonin circulating in the blood at all stages of ontogenesis. Thus, local sensitivity to serotonin provides the possibility of systemic humoral coordination of the development and functioning of the adrenal glands and other peripheral organs. From this perspective, the importance of local serotoninergic systems for developmental biology and medicine becomes clear.
Human pluripotent stem cell (PSC) research is currently focused on selecting conditions and growth factors that better mimic preimplantation development and germ cell differentiation, which is important for disease modeling using PSC. Previously, it was shown that, in the presence of the chemokine CCL2, human PSCs acquire properties attributable for preimplantation blastomeres, namely, they activate the JAK-STAT3 signaling pathway and increase the mRNA level of the hypoxic response genes. However, CCL2 is hardly used in human PSCs cultivation, and its effect is described in a single study. We continued to study the effect of CCL2 on human PSC and showed that human embryonic and induced pluripotent stem cells cultured with CCL2 have an increased level of the oxygen-dependent protein subunits HIF1A and HIF2A, which are necessary to trigger the hypoxic response, as well as elevated levels of the key pluripotency transcription factor proteins OCT4, NANOG, KLF4, SOX2, and TFCP2L1. In addition, the presence of CCL2 had a positive effect on directed endothelial differentiation, accelerating the maturation of progenitors and enhancing the angiogenic potential of differentiated derivatives.
Human pluripotent stem cells (PSCs) can be maintained in a naïve or primed state of pluripotency in vitro. Being in one state or another, PSCs have different potentials of differentiation into extra-embryonic and embryonic cells. In terms of the expression profile and epigenetic pattern of the genome, naïve PSCs are comparable to the cells of the inner cell mass of the blastocyst, while primed PSCs are similar in their characteristics to the cells of the postimplantation epiblast. Reprogramming of primed PSCs into the naïve state and maintenance of naïve PSCs in culture is a crucial issue in studying the epigenetic processes of preimplantation development of the human embryo and methods for efficient differentiation of PSCs into derivatives of embryonic and extra-embryonic cells. The aim of this work is to reprogram primed induced pluripotent stem cells (iPSCs) into a naïve pluripotent state to obtain a homogeneous population of iPSCs according to the state of pluripotency in culture. The task of this work is to develop a protocol and conditions for reprogramming primed iPSCs into a naïve state of pluripotency. In this work, naïve iPSCs were obtained under conditions of application of growth factors FGF2 and TGFβ1 and inhibition of GSK3β and the MEK/ERK signaling pathway (2iF medium). Pretreatment of primed iPSCs with histone deacetylase inhibitors (HDACi) changes the cell morphology and gene expression profile of PSCs towards an earlier state of pluripotency. Using pretreatment of HDACi primed iPSCs followed by maintenance in 2iF medium, the authors obtained naïve iPSCs comparable in colony morphology and expression profile of naïve state marker genes to control naïve iPSCs obtained in RSeT medium. In order to confirm the naïve state of pluripotency of iPSCs obtained 2iF conditions, it is necessary to carry out single cell RNA sequencing.
Genome editing in human pluripotent stem cells using programmable nucleases makes it possible to create models of hereditary pathologies using directed transgenesis, gene knockout, and replacement of individual nucleotides in DNA sequences. Using CRISPR/SpCas9-mediated homologous recombination at the AAVS1 locus, clones of human induced pluripotent stem cells (iPSCs) ICGi022-A (Malakhova et al., 2020) were obtained, which carry transgenes of two variants of the nuclease AsCas12a (also known as AsCpf1), recognizing different PAM consensuses, and the reverse doxycycline transgene-dependent transactivator M2rtTA. For each AsCas12a variant, the lines ICGi022-A-6 (AsCas12a, PAM 5'-TTTV-3') and ICGi022-A-7 (AsCas12a, PAM 5'-TYCV-3') were obtained. Using Western blot analysis, it was shown that the addition of doxycycline to the culture medium causes activation of the expression of AsCas12a(TTTV) and AsCas12a(TYCV) proteins. The resulting transgenic iPSC clones were subjected to molecular and cytogenetic analysis. Using quantitative PCR and immunocytochemical analysis, it was shown that they have a high level of mRNA expression of gene markers of pluripotent cells, namely OCT4, NANOG , and SOX2 , as well as specific expression of protein markers OCT4, SOX2, SSEA-4, and TRA-1-60. In addition, using iPSCs spontaneous differentiation into embryoid bodies, it was found that transgenic clones can give derivatives of all three primitive germ layers: ectoderm, mesoderm, and endoderm. Cytogenetic analysis showed that transgenic iPSC clones have a normal karyotype, 46,XX.
At the early 1970s, in the USSR, L.V. Beloussov and his colleagues from Moscow State University put forward a hypothesis about the possible role of mechanical forces and stresses in the organization of developing living systems. The authors discovered stage-specific patterns of mechanical stresses during amphibian embryonic development and showed that mechanical stresses are necessary for the organization of morphogenesis and cellular differentiation. As a result of the long-term work of Moscow embryologists, morphomechanics, new interdisciplinary science at the intersection of developmental biology and mechanics, was born. In the 21st century, mechanisms of mechano-dependent gene expression, cellular and nuclear mechanotransduction are intensively studied. The idea of the organizing role of mechanical forces and stresses in living systems remains very relevant.
Primary culture of granulosa cells is a prerequisite for a complete study of the normal functioning of the ovary and its pathologies. In this work, we selected the optimal protocol for obtaining a primary culture of mouse granulosa cells in the most functionally active state and revealed the effects of androstenedione and serotonin on the expression of ovarian markers that reflect the functional status of granulosa cells. The morpho-functional analysis of the ovary after PMSG stimulation revealed that 48 hours after PMSG stimulation is the optimal time for obtaining granulosa cells in the most active functional state. Using the set of 14 ovarian functional state marker genes we reveal that androstenedione inhibits cumulus and immature granulosa markers but stimulates genes characteristic of the mature state of granulosa. At the same time, granulosa cells express serotonergic receptors and transporter SERT. The ovarian marker genes expression analysis revealed that serotonin affects the expression of genes characterizing the differentiation of granulosa cells towards cumulus cells. Summarizing, we can conclude that serotonin and androstenedione have an antagonistic effect on the functional state of mouse granulosa cells in primary culture in vitro.
Pluripotent stem cells (PSCs) are a unique cell type that can differentiate into all cell types in the body. In PSC culture, subpopulations with different levels of pluripotency may exist, which leads to different results during their differentiation. One of the key factors that determine the state of pluripotency and influence the differentiation potential of PSCs is the epigenetic state of cells, including the level of histone deacetylation. Activation of histone deacetylase (HDAC) in human and mouse PSCs increases the percentage of heterochromatin. In this work, we used a protocol for the differentiation of embryoid bodies from induced human pluripotent hiPSC cells designed for the formation of ectoderm and neuroectoderm with their subsequent development into skin organoids. However, after hiPSCs were exposed to HDAC inhibitors (sodium butyrate and valproic acid), the direction of their differentiation changed: mesoderm was formed, which subsequently developed into contracting cardiospheres.
