Embryonic Stages Research Articles

Description of the Life Cycle Stages of the Parasitic Cymothoid, Cymothoa indica Schioedte and Meinert, 1884, and Its Prevalence in Commercial Fishes from Chilika Lagoon, India.

To study the morphology of all the life stages and the life cycle of the parasitic isopod Cymothoa indicaSchioedte and Meinert, 1884, and its prevalence in different commercial fishes in the Chilika Lagoon, India. From April 2021 to December 2022, different life stages of the said parasites were collected from five different fish species from four localities of the Chilika Lagoon. The parasites were carefully removed from the host with a pair of forceps and then identified following standard literature and description. The morphology of all life stages, life cycle, and prevalence of the isopod C. indica were carried out as per the standard protocol. A total of 1252 host fishes were analysed. The total prevalence was 44.5%. The host with the highest prevalence of C. indica was Glossogobius giuris, with 58.79% of the hosts parasitized by at least one parasite individual. Followed by the host Datnoides polota (50.98%), Johnius dussumieri (46.25%), Etroplus suratensis (28.45%) and the least prevalence was in Lates calcarifer (14.70%). The description of the life stages is based on the observation of 523 females, 116 males, 46 Juveniles, and 50 embryonic stages of the said parasites. The description of all the life stages and life cycles certainly helps to identify this species with clarity and ease in understanding the species' biology. In future, this study may be helpful in the effective management towards the improvement of aquaculture productivity.

Sustainable Development Goals and Board Structure: Connecting the Dots in The Energy Sector

Purpose: Framed on the Resource-Based View, the objective of this research was to investigate the effect of the structure of the board of directors on the engagement of firms with the sustainable development goals (SDG). Theoretical framework: Resource-Based View (RBV) and Sustainable development goals. Method: 100 firms in the energy sector based in the main emerging economies of the world were analyzed. To test the proposed hypotheses, an analysis of panel data and logistic regression model was performed. Result and Conclusion: The board structure in emerging countries plays a key role for firms to achieve greater engagement with the SDGs. The board size has a negative effect on SDGs, while the presence of social responsibility and audit committees has a positive effect on firms’ engagement with the SDGs. Research implications: It is necessary to consider committees as key configurations of the board structure, even if these are not mandatory in terms of regulation. Establishing, strengthening and encouraging the maintenance of committees focused on sustainability practices is to contribute to promising organizational results and to the reduction of negative externalities. Originality: In addition to confirming the Resource-Based View approach, our study examines the energy sector, which is one of the main agendas for discussions on climate change at a global level. We address the understanding of SDG in business, a field of research still in an embryonic stage. Although several studies have analyzed a variety of contexts together, we focused on emerging economies, bringing specific evidence to the sample countries.

Exposure of Zebrafish Embryos to Urea Affects NOS1 Gene Expression in Neuronal Cells

Nitrogen-based fertilizers represent the most common fertilization tools, particularly used in crop food agriculture, despite the low cost-efficiency and the high negative environmental impact. At present, there is still inadequate information available about the effects of urea on human health; nevertheless, previous studies in animals observed that high urea concentration exposure can damage different tissues, including the brain. In several vertebrates, a crucial factor involved in neuronal cell formation is represented by the gas molecule, nitric oxide (NO), derived from the conversion of arginine to citrulline through the enzymatic activity of nitric oxide synthases (NOS). In zebrafish, three different isoforms of the NOS gene are known: nos1, nos2a, and nos2b. In the present study we show that nos1 represents the unique isoform with a stable high expression in the brain and spinal cord during all the embryonic stages of zebrafish development. Then, by using a specific transgenic zebrafish line, Tg(HuC:GFP), to mark neuronal cells, we observed nos1 to be specifically expressed in neurons. Interestingly, we observed that urea exposure at sub-lethal doses affected cell proliferation and the number of nos1-expressing cells, inducing apoptosis. Consistently, brain NO levels were observed to be reduced in urea-treated animals compared to untreated ones. This finding represents the first evidence that urea exposure affects the expression of a key gene involved in neuronal cell formation during embryonic development.

Microplastics and TiO2 nanoparticles mixture as an emerging threat to amphibians: A case study on bullfrog embryos

Emerging contaminants can act as contributing factors to the decline of amphibian populations worldwide. Recently, scientists have drawn attention to the potential ecotoxicity of microplastics and nanomaterials in amphibians, however, their possible effects on embryonic developmental stages are still absent. Thus, the present study analyzed the developmental toxicity of environmentally relevant concentrations of polyethylene microplastics (PE MPs; 60 mg/L) and titanium dioxide nanoparticles (TiO2 NPs; 10 μg/L), isolated or in combination (Mix group) on bullfrog embryos, Aquarana catesbeiana, adapting the Frog Embryo Teratogenesis Assay (FETAX, 96h). Allied to the FETAX protocol, we also analyzed the heart rate and morphometric data. The exposure reduced the survival and hatching rates in groups exposed to TiO2 NPs, and to a lesser extent, also affected the Mix group. TiO2 NPs possibly interacted with the hatching enzymes of the embryos, preventing hatching, and reducing their survival. The reduced effects in the Mix group are due to the agglomeration of both toxicants, making the NPs less available for the embryos. PE MPs got attached to the gelatinous capsule of the chorion (confirmed by fluorescence microscopy), which protected the embryos from eventual direct effects of the microplastics on the hatching and survival rates. Although there were no cardiotoxic effects nor morphometric alterations, there was a significant increase in abdominal edemas in the hatched embryos of the PE MPs group, which indicates that osmoregulation might have been affected by the attachment of the microplastics on the embryos’ gelatinous capsule. This study presents the first evidence of developmental toxicity of environmental mixtures of microplastics and nanoparticles on amphibians and reinforces the need for more studies with other amphibian species, especially neotropical specimens that could present bigger sensibility. Our study also highlighted several features of the FETAX protocol as useful tools to evaluate the embryotoxicity of several pollutants on amphibians.

Studies on the embryonic development and larval infection potential of the stomach bot flies, Gasterophilus pecorum

Endangered Przewalski's horses have faced severe infections from Gasterophilus pecorum (Diptera, Gastrophilidae) in Xinjiang's Kalamaili Nature Reserve (KNR). This study examines G. pecorum's development and infection patterns in embryonic and larval stages, crucial for understanding horse botfly disease in desert grasslands. For the incubation of G. pecorum fertilized eggs, we established the six distinct temperature gradients: 16 °C, 20 °C, 24 °C, 28 °C, 30 °C, and 32 °C. Using the least squares method, we calculated the correlation between the developmental threshold temperature of the eggs and their cumulative effective temperature. Furthermore, we meticulously recorded the survival duration of the larvae across a spectrum of temperature gradients (−20 °C, −10 °C, 4 °C, 10 °C, 20 °C, and 30 °C) and under varying conditions (dark and light). This method allows us to analyze and interpret the impact of these environmental factors on larval survival durations. 1) The formula for predicting the embryonic development period of G. pecorum was N = (182.7 ± 12.03)/[T-(3.191 ± 1.48)], where the developmental threshold temperature was 3.191 ± 1.48 °C, and the effective accumulated temperature was 182.7 ± 12.03 d°C 2) The model describing the relationship between the embryonic development rate and temperature was: y = 0.0001x2+0.0007x+0.0378, demonstrating a positive correlation between the development rate and temperature (R-sq = 0.989, p < 0.001). 3) Larvae in the dark group exhibited a longer survival time, with the longest being 9 months at 4 °C. The adaptation of G. pecorum's embryonic development to cold temperature, combined with the extended survival period of larvae in the egg state, significantly increases the infection potential of G. pecorum in colder climates. This discovery offers essential insights into the predominance of G. pecorum in the KNR region and provides a crucial biological basis for the prevention of myiasis and the conservation of vulnerable species, such as Przewalski's horses.

Techniques for Rapidly Sampling Six Crucial Organs in Adult Xenopus.

Xenopus has been a powerful model organism for understanding vertebrate development and disease for over a hundred years. While experimental analysis and dissection techniques of the embryo have been well documented, descriptions of adult Xenopus structures and organs, together with techniques for working with adults, have not been updated to take into consideration the requirements of such modern approaches as quantitative proteomics and single-cell transcriptomics. The cell-type and gene-centric perspectives require contrasting observations in embryonic stages to those in adult tissues. The organs of the larva undergo significant changes in their overall structure, morphology, and anatomical location all along the larval to adult transition, most notably during massive metamorphosis remodeling. Establishing robust standards for organ identification and dissection is crucial to ensure datasets resulting from studies performed at different laboratories can be consistent. The present protocol identifies six of the organs in the adult Xenopus, demonstrating methods for dissection and sampling of the heart ventricle, liver, fat body, pancreas, paired kidney, and skin of the adult Xenopus. Depending on the preservation methods, the dissected organs can be used for quantitative proteomics, single cell/nuclei transcriptomics, in situ hybridization, immunohistochemistry, histology, etc. This protocol aims to standardize tissue sampling and facilitate multi-lab investigations of the adult organ systems.

Heterogeneity in maternal mRNAs within clutches of eggs in response to thermal stress during the embryonic stage

BackgroundThe origin of variation is of central interest in evolutionary biology. Maternal mRNAs govern early embryogenesis in many animal species, and we investigated the possibility that heterogeneity in maternal mRNA provisioning of eggs can be modulated by environmental stimuli.ResultsWe employed two sibling species of the ascidian Ciona, called here types A and B, that are adapted to different temperature regimes and can be hybridized. Previous study showed that hybrids using type B eggs had higher susceptibility to thermal stress than hybrids using type A eggs. We conducted transcriptome analyses of multiple single eggs from crosses using eggs of the different species to compare the effects of maternal thermal stress on heterogeneity in egg provisioning, and followed the effects across generations. We found overall decreases of heterogeneity of egg maternal mRNAs associated with maternal thermal stress. When the eggs produced by the F1 AB generation were crossed with type B sperm and the progeny (‘ABB’ generation) reared unstressed until maturation, the overall heterogeneity of the eggs produced was greater in a clutch from an individual with a heat-stressed mother compared to one from a non-heat-stressed mother. By examining individual genes, we found no consistent overall effect of thermal stress on heterogeneity of expression in genes involved in developmental buffering. In contrast, heterogeneity of expression in signaling molecules was directly affected by thermal stress.ConclusionsDue to the absence of batch replicates and variation in the number of reads obtained, our conclusions are very limited. However, contrary to the predictions of bet-hedging, the results suggest that maternal thermal stress at the embryo stage is associated with reduced heterogeneity of maternal mRNA provision in the eggs subsequently produced by the stressed individual, but there is then a large increase in heterogeneity in eggs of the next generation, although itself unstressed. Despite its limitations, our study presents a proof of concept, identifying a model system, experimental approach and analytical techniques capable of providing a significant advance in understanding the impact of maternal environment on developmental heterogeneity.

Identification and analysis of key circRNAs in the mouse embryonic ovary provides insight into primordial follicle development.

CircRNAs are a class of noncoding RNAs with tissue- and development-specific expression characteristics. In many mammals, primordial follicle development begins in the embryonic stage. However, the study of circRNAs in primordial follicle development in mice has not been reported. In this study, ovaries were collected from mouse foetuses at 15.5 days post coitus (dpc) and 17.5 dpc, which are two key stages of primordial follicle development. A total of 4785 circRNAs were obtained by using RNA-seq.Of these, 83 differentially expressed circRNAs were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that these differential circRNAs were mainly involved in the regulation of reproductive development. Through qRT-PCR, back-splice sequence detection and enzyme digestion protection experiments, we found that circ-009346, circ-014674, circ-017054 and circ-008296 were indeed circular. Furthermore, circ-009346, circ-014674 and circ-017054 were identified as three key circRNAs by analysing their expression in the ovaries of mice at different developmental stages. The circRNA-miRNA-mRNA interaction network was constructed and validated for target miRNA and mRNA using qRT-PCR. The interacting genes circ-009346, circ-014674, and circ-017054 were subjected to KEGG enrichment analysis. We found that circ-014674 may participate in the assembly and reserve of primordial follicles through oestrogen and the Janus kinase (JAK) signal transducer and activator of transcription (STAT) signalling pathway (JAK-SATA). Circ-009346 and circ-017054 may have similar functions and are involved in the activation and growth of primordial follicles through the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signalling pathways. Based on our findings, three circRNAs associated with primordial follicle development were identified, and their potential mechanisms of regulating primordial follicle development were revealed. These findings will help us better understand the molecular mechanism of circRNAs in primordial follicles and provide important references and targets for the development of primordial follicles.

Cardiac lipidomic profiles in mice undergo changes from fetus to adult

AimsLipids are essential cellular components with many important biological functions. Disturbed lipid biosynthesis and metabolism has been shown to cause cardiac developmental abnormality and cardiovascular diseases. In this study, we aimed to investigate the composition and the molecular profiles of lipids in mammalian hearts between embryonic and adult stages and uncover the underlying links between lipid and cardiac development and maturation. Materials and methodsWe collected mouse hearts at the embryonic day 11.5 (E11.5), E15.5, and the age of 2 months, 4 months and 10 months, and performed lipidomic analysis to determine the changes of the composition, molecular species, and relative abundance of cardiac lipids between embryonic and adult stages. Additionally, we also performed the electronic microscopy and RNA sequencing in both embryonic and adult mouse hearts. Key findingsThe relative abundances of certain phospholipids and sphingolipids including cardiolipin, phosphatidylglycerol, phosphatidylethanolamine, and ceramide, are different between embryonic and adult hearts. Such lipidomic changes are accompanied with increased densities of mitochondrial membranes and elevated expression of genes related to mitochondrial formation in adult mouse hearts. We also analyzed individual molecular species of phospholipids and sphingolipids, and revealed that the composition and distribution of lipid molecular species in hearts also change with development. SignificanceOur study provides not only a lipidomic view of mammalian hearts when developing from the embryonic to the adult stage, but also a potential pool of lipid indicators for cardiac cell development and maturation.

Functional importance of groups I and II chitinases, CHT5 and CHT10, in turnover of chitinous cuticle during embryo hatching and post-embryonic molting in the red flour beetle, Tribolium castaneum

Chitinases (CHT) comprise a large gene family in insects and have been classified into at least eleven subgroups. Many studies involving RNA interference (RNAi) have demonstrated that depletion of group I (CHT5s) and group II (CHT10s) CHT transcripts causes lethal molting arrest in several insect species including the red flour beetle, Tribolium castaneum, presumably due to failure of degradation of chitin in their old cuticle. In this study we investigated the functions of CHT5 and CHT10 in turnover of chitinous cuticle in T. castaneum during embryonic and post-embryonic molting stages. RNAi and transmission electron microscopic (TEM) analyses indicate that CHT10 is required for cuticular chitin degradation at each molting period analyzed, while CHT5 is essential for pupal-adult molting only. We further analyzed the functions of these genes during embryogenesis in T. castaneum. Real-time qPCR analysis revealed that peak expression of CHT10 occurred prior to that of CHT5 during embryonic development as has been observed at post-embryonic molting periods in several other insect species. With immunogold-labeling TEM analysis using a fluorescein isothiocyanate-conjugated chitin-binding domain protein (FITC-CBD) probe, chitin was detected in the serosal cuticle but not in any other regions of the eggshell including the chorion and vitelline membrane layers. Injection of double-stranded RNA (dsRNA) for CHT5 (dsCHT5), CHT10 (dsCHT10) or their co-injection (dsCHT5/10) into mature adult females had no effect on their fecundity and the resulting embryos developed normally inside the egg. There were no obvious differences in the morphology of the outer chorion, inner chorion and vitelline membrane among eggs from these dsRNA-treated females. However, unlike dsCHT5 eggs, dsCHT10 and dsCHT5/10 eggs exhibited failure of turnover of the serosal cuticle in which the horizontal chitinous laminae remained intact, resulting in lethal embryo hatching defects. These results indicate that group I CHT5 is essential for pupal-adult molting, whereas group II CHT10 plays an essential role in cuticular chitin degradation in T. castaneum during both embryonic hatching and all of the post-embryonic molts. CHT10 can serve in place of CHT5 in chitin degradation, except during the pupal-adult molt when both enzymes are indispensable to complete eclosion.

Kinship influences the metamorphic traits of Asiatic toad (Bufo gargarizans) larvae, in Central China

Kin recognition has been selected by natural selection because it can enhance the chances of cooperation among close relatives, but it could also be an accidental consequence of other life-history processes. In this study, we carried out experiments by using Asiatic toad tadpoles (Bufo gargarizans) to evaluate the hypothesis that: (1) individuals can use waterborne chemical cues or combine other possible cues to communicate kinship identity when exposed to kin during early ontogeny; (2) unfamiliar siblings (or familiar non-siblings) should have similar growth with unfamiliar non-siblings because the former is not able to identify their relatives (or may not consider familiar non-siblings as kin); (3) the familiar siblings may obtain a more equal resource share in populations of siblings, thus size variation is weak. The first and second predictions were partially better supported: kinship had a positive effect on tadpole growth, obtained larger mass at metamorphosis, and increased survival, but development time was longer than that of unfamiliar non-siblings. Further, the growth of unfamiliar siblings and familiar non-siblings was different from that of familiar siblings, suggesting that Asiatic toad tadpoles lose kin-recognition ability when isolated across the embryonic stage or may not be considered as siblings when exposed to water from non-sibling groups during early embryonic development. Thus, besides chemical cues, Asiatic toad tadpoles need to combine other possible modalities to communicate kinship identity. The third prediction was supported weakly. Therefore, our results suggest that exposure to kin during early embryonic development is essential for altering kin-recognition ability. More importantly, familiar sibling groups can be expected to develop slower and spend more time in the water, allowing more time for feeding and growth, which is consistent with kin selection theory, suggesting that natural selection should drive the evolution of mechanisms that minimize the competitive intensity between sibling groups.

Skin sarcoma stage detection using antenna resonant scale

In this paper, a small antenna is proposed to diagnose skin sarcoma at an embryonic stage. The antenna has an area of 30.54 × 15.27 mm2 and resonates at 1429 MHz with a reflection coefficient of −17.64 dB. The structure consists of a 35 μm copper sheet etched on a 1.6 mm FR-4 substrate. The diagnosis is based on the resonance frequency shift, and the SAR (Specific Absorption Rate) variation when the antenna is positioned on malignant tissue. For the simulations, a three-layer body phantom (skin, fat, muscle), and a half-sphere tumor phantom were considered. Simulations of the antenna performances showed that for a tumor of 100 μm, the resonant frequency, and the SAR decrease by 2 MHz, and 1.09 mW/Kg, respectively. In addition to sarcoma detection, the antenna’s 3.6 dBi gain allows for 124.47 m biomedical communication links in a complex environment.

Heat shocks during egg incubation led to developmental, morphological, and behavioral differences in Arctic charr (Salvelinus alpinus).

Temperature variation is affecting fish biodiversity worldwide, causing changes in geographic distribution, phenotypic structure, and even species extinction. Incubation is a critical stage for stenothermic species, which are vulnerable to large temperature fluctuations, and its effects on the phenotype at later developmental stages are understudied, despite the fact that the phenotype being essential for organism ecology and evolution. In this study, we tested the effects of heat shocks during the embryonic period on the phenotype of Arctic charr (Salvelinus alpinus). We repeatedly quantified multiple phenotypic traits, including morphology, development, and behavior, over a period of 4 months, from hatching to juvenile stage in individuals that had experienced heat shocks (+ 5°C on 24 h, seven times) during their embryonic stage and those that had not. We found that heat shocks led to smaller body size at hatching and a lower sociability. Interestingly, these effects weakened throughout the development of individuals and even reversed in the case of body size. We also found an accelerated growth rate and a higher body condition in the presence of heat shocks. Our study provides evidence that heat shocks experienced during incubation can have long-lasting effects on an individual's phenotype. This highlights the importance of the incubation phase for the development of ectothermic organisms and suggests that temperature fluctuations may have significant ecological and evolutionary implications for Arctic charr. Given the predicted increase in extreme events and the unpredictability of temperature fluctuations, it is critical to further investigate their effects on development by examining fluctuations that vary in frequency and intensity.

Spatial pattern characteristics and optimization policies of low-carbon innovation levels in the urban agglomerations in the Yellow River Basin

This paper refines a comprehensive index of urban low-carbon innovation based on urban low-carbon innovation concept and an urban low-carbon innovation community structure and function. This index is complemented by an indicator reflecting equity in terms of urban-rural income gap, some indicators of low-carbon knowledge and technology innovation, as well as an indicator of the characteristics of a carbon circular economy, and a further refinement of the indicator of low-carbon innovation system. We use the entropy value method, kernel density analysis, gravity model, and social network analysis to study the low-carbon innovation spatial pattern in urban agglomerations (UAs) of the Yellow River Basin (YRB). Innovations in the findings are: (1) the low-carbon innovation level in the UAs in the YRB decreases in spatial distribution from the downstream to the midstream to the upstream UAs. (2) Reveal the spatial pattern laws of low-carbon innovation levels in different types of UAs in the YRB. The spatial pattern in regional level UAs is more complex and hierarchical than that in area level UAs; but there are still gaps in the hierarchy of spatial patterns of low-carbon innovation levels between UAs at the regional level, as well as between UAs at the area level. The spatial pattern of two regional-level UAs in the YRB is transitioning from a low-carbon innovation point-axis to a low-carbon innovation network structure, and the spatial pattern of one regional-level UAs is at the embryonic stage of the low-carbon innovation point-axis structure. The spatial pattern of one area-level UA is at the embryonic stage of a low-carbon innovation point-axis structure, and the spatial pattern of three area-level UAs is at the stage of low-carbon innovation pole. The spatial pattern of low-carbon innovation becomes more complex and hierarchical as we move from upstream to midstream to downstream UAs. (3) Use social network analysis and the study show that the low-carbon innovation network is dominated by the internal correlations among the UAs in the upstream, midstream, and downstream. The low-carbon innovation linkages between upstream, midstream and downstream UAs are weak. Finally, we put forward corresponding policy recommendations.

Acidosis defense mechanisms in the preimplantation stages of embryos in BALB/c strain mice

Regulation of intracellular pH (pHi) is an important homeostatic function of cells. There are three major pHi regulatory mechanisms: the HCO3−/Cl− exchanger (AE), which alleviates alkalosis, and the Na+/H+ exchanger (NHE) and Na+,HCO3−/Cl− exchanger (NDBCE), both of which counteract acidosis. NHE activity, which is high at the germinal vesicle stage of oocyte, is inhibited during meiotic maturation, while this inhibition is abolished when the oocyte reaches the pronuclear (PN) stage of the zygote. On the other hand, we have previously found that NDBCE performs complementary regulation against acidosis during meiotic maturation. Additionally, we found that AE activity, which is a defense mechanism against alkalosis, gradually decreases during preimplantation period of embryonic development. Considering that NHE activity is inhibited during meiotic maturation and AE activity gradually decreases during embryonic development stages, we investigated whether NHE and NDBCE activities, both of which act against acidosis, functionally change from the PN zygote to the blastocyst stage of the embryo and identified these pH-regulating proteins at the molecular level in mice of the Balb/c strain. PN zygotes, two-cell (2-c), four-cell (4-c), morula and blastocyst stage embryos were obtained from 5-8-week-old, sexually mature female Balb/c mice by using the classical superovulation procedure. pHi was recorded by using the microspectrofluorometric technique on zygotes and embryos simultaneously loaded with the pH-sensitive fluorophore, 2′,7′-Bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). The activities of NHE and NDBCE were determined from the recovery curve of induced-acidosis in bicarbonate-free and bicarbonate-containing media, respectively. Specific inhibitors such as cariporide (1 μM), S3226 (1 and 10 μM), EIPA (1, 5, and 25 μM), and amiloride (1 mM) were used to functionally identify NHE isoforms, and the nonspecific inhibitor 4,4′–diisocyanatostilbene-2,2′ disulphonic acid, disodium salt (DIDS) was used to confirm NDBCE activity. The isoforms of the pHi-regulatory proteins were also identified by molecular biology using real-time PCR. We found that NHE activity was high at all embryonic stages, and differences between stages were not significant. Functional and molecular findings indicated that isoforms of NHE 1 and 5 are present in the blastocyst, whereas isoforms of NHE 1, 3, and 4 are functional at earlier embryonic stages. Although the contribution of NDBCE activity to recovery from induced-acidosis was detected at all embryonic stages, it was significant only in the PN zygote and the 2-c embryo. This finding was confirmed by molecular analysis, which detected the expression of SLC4A8 encoding NDBCE at all embryonic stages. In conclusion, NHE is an active and important defense mechanism against acidosis and is encoded by at least two protein isoforms in all stages of the Balb/c strain of mice. NDBCE has a supportive function in all embryonic stages, especially in the PN zygote and the 2-c embryo. Preimplantation stage embryos have effective mechanisms to defend against acidosis in response to their metabolic end products (increased acid load) and the acidic environment in utero.

The mechanism of pattern transitions between formation and dispersion

On the surface of living organisms, a wide variety of patterns can be observed, some of which change during their growth process. For instance, Pelodiscus sinensis exhibits distinct black patterns on its vivid orange plastron during the embryonic and juvenile stages, but as it matures, the black patterns gradually disappear, resulting in a whitened plastron. This pattern transition is a mysterious phenomenon that forms and vanishes on the plastron, a ventral part with low visibility to both predators and peers. Our research aims to focus on understanding the mechanisms behind such pattern transitions and proposes a model capable of representing pattern formation and dispersion.To understand the changing patterns, we propose a hypothesis based on a reaction–diffusion system with a time-dependent growing spatial domain. This mathematical framework suggests the occurrence of the dispersion phenomenon. Specifically, we focus on the dilution term within the system under the growing-domain condition. While previous studies have investigated the effects of growth domains, this study specifically addresses the role of the time-dependently growing domain effects - change of diffusion coefficient and dilution - in reaction–diffusion systems.Our research sheds light on the intricate phenomenon of pattern formation and dispersion on the surface of living organisms, proposing a natural system based on the effects of growing domain, namely, a model of reaction-dilution-diffusion systems.

A study of the genotoxicity, fertility and early embryonic development toxicity of rotigotine behenate extended-release microspheres.

Continuous dopaminergic stimulation (CDS) has become an important strategy for the development of drugs to treat Parkinson's disease (PD). Rotigotine behenate extended-release microspheres (RBEM) for injection represent a new treatment regime for CDS and are undergoing clinical trials. In this study, we aimed to investigate the effect of RBEM on genotoxicity, fertility and early embryonic development. We used the Ames test, Chinese hamster lung (CHL) cell chromosome aberration test and the mouse bone marrow micronucleus test, to evaluate the genotoxicity of RBEM. These tests were all negative, thus indicating that RBEM did not induce genotoxicity. In reproduction toxicity testing in male rats on obvious findings following intramuscular administration (i.m.) of RBEM at up to 540 mg/kg (P > 0.5), when female rats were administered with RBEM in the dose range of 60 to 540 mg/kg given (i.m.), there were clear effects on fertility and early embryonic development. These results indicated that RBEM could induce toxicity in female rats and exert effect on fertility and early embryonic development stage.

Dermal FOXO3 activity in response to Wnt/β-catenin signaling is required for feather follicle development of goose embryos (Anser cygnoides)

Feather is an important economic trait of poultry, and growth and development state of feathers plays an important role in the economic value of poultry. Dermal fibroblasts are required for structural integrity of the skin and for feather follicle development. How FOXO3 affects feather follicle development as skin tissues change during goose embryo (Anser cygnoides) development and growth is not well understood. Here, we demonstrate that in vitro culture of single feathers and skin tissue results in changes in feather morphological structure by adding drugs to the culture medium that affect FOXO3 expression. We used feather follicles to show that during growth, the root location of feathers, the dermis layer, affects cell proliferation and apoptosis and regulates the expression of major genes in the Wingless-types/beta-catenin (Wnt/β-catenin) signaling pathway through the activity of FOXO3 in dermal fibroblasts. Feathers and dorsal skin tissues develop the correct structure, but feather length and width and feather follicle diameter change significantly (p < 0.05) without significant changes in feather follicle density (p > 0.05). Transfected dermal fibroblasts also showed that FOXO3 affected the formation and development of feather follicles in the embryonic stage by regulating the Wnt/β-catenin signaling pathway. Therefore, this study reveals the critical role of dermal fibroblast-FOXO3-induced Wnt/β-catenin signaling in promoting the formation and development of embryonic feather follicles.

Ontogeny of a threatened freshwater minnow: Implications for conservation

AbstractInvestigating the ontogeny of threatened freshwater fishes is vital for designing future conservation actions that will increase the potential of species' persistence. This study provides a detailed description of the early life stages of a threatened freshwater fish species, the Evrotas minnow Pelasgus laconicus, which occupies aquatic ecosystems with extreme seasonal hydrological variation. The study of the embryonic and juvenile stages was conducted in vivo using light microscopy from eggs obtained from acclimatized wild spawners at 20 ± 1°C. Fertilized eggs were spherical and transparent with a mean diameter of 1.24 ± 0.06 mm and the average length of free embryos at hatching was 3.85 mm NL (notochord length). The main morphological changes observed are related to the absorption of the yolk, the increase and distribution of the melanophores and the sequential development of the fins. In conclusion, the Evrotas minnow was identified as a multiple spawner, exhibiting a protracted reproductive period (March to August), a particularly short egg‐hatching period (5–6 days), a short free embryo stage and a rapid onset of exogenous feeding (2 days). The conservation implications of our study, such as safety stock creation, population reintroduction, conservation of fish refugia and breeding habitats and beaver dam analogues, are discussed.

Apically localized PANX1 impacts neuroepithelial expansion in human cerebral organoids

Dysfunctional paracrine signaling through Pannexin 1 (PANX1) channels is linked to several adult neurological pathologies and emerging evidence suggests that PANX1 plays an important role in human brain development. It remains unclear how early PANX1 influences brain development, or how loss of PANX1 alters the developing human brain. Using a cerebral organoid model of early human brain development, we find that PANX1 is expressed at all stages of organoid development from neural induction through to neuroepithelial expansion and maturation. Interestingly, PANX1 cellular distribution and subcellular localization changes dramatically throughout cerebral organoid development. During neural induction, PANX1 becomes concentrated at the apical membrane domain of neural rosettes where it co-localizes with several apical membrane adhesion molecules. During neuroepithelial expansion, PANX1−/− organoids are significantly smaller than control and exhibit significant gene expression changes related to cell adhesion, WNT signaling and non-coding RNAs. As cerebral organoids mature, PANX1 expression is significantly upregulated and is primarily localized to neuronal populations outside of the ventricular-like zones. Ultimately, PANX1 protein can be detected in all layers of a 21–22 post conception week human fetal cerebral cortex. Together, these results show that PANX1 is dynamically expressed by numerous cell types throughout embryonic and early fetal stages of human corticogenesis and loss of PANX1 compromises neuroepithelial expansion due to dysregulation of cell-cell and cell-matrix adhesion, perturbed intracellular signaling, and changes to gene regulation.