Early Stages Of Organogenesis Research Articles

Cu(II)-Dependent Spine Development Injury in Zebrafish (Danio rerio) with Organ Heterogeneous Cu Imbalance.

Growing evidence suggests that the imbalance of Cu leads to multiorgan diseases or other adverse effects, but the underlying mechanisms remain largely unknown. Herein, we used zebrafish to uncover the mystery of organ heterogeneous responses to Cu stress and Cu(II)-dependent spine developmental injury in the early organogenesis stage. We first demonstrated that Cu(I) was distributed in the entire body, but high contents of Cu(II) were accumulated in the yolk sac and eye in normal zebrafish larvae. Cu exposure from birth to 144 hpf caused no obvious damage to Cu-metabolizing organs (liver and intestine), despite the elevated Cu(I) and Cu(II) levels. However, the spine was more sensitive to the Cu exposure. In the spine region, the Cu(I) level remained stable, whereas the level of Cu(II) significantly increased, which was highly associated with spine development injury. A significant negative correlation between Cu(II) and the spine-related parameters was identified. Moreover, cuproptosis caused spine development deformation during the early embryogenesis stage. Spine-related pathways such as somitegenesis significantly changed in the early embryogenesis period, and 5 spine-related pathways were significantly altered in the larval stage at 96 hpf. Our study suggested that Cu stress induced organ heterogeneous Cu imbalance and Cu(II)-dependent spine development injury in zebrafish.

INFLUENCE OF BIOTECHNOLOGICAL COMPLEX PREPARATIONS OF LIQUID ON NITROGEN METABOLISM IN PRODUCTIVE ORGANS OF THE WHEAT WINTER FORMATION

The influence of complex preparations on nitrogen metabolism in the early stages of winter wheat organogenesis was studied. The activivity of key enzymes of nitrogen metabolism, TBA-active products, NH3 concentration, and chlorophyll content under the experimental condition were determined. There is a tendency to increase the activity of AsAT, while the mixture of macronutrients on the enzymatic activity of another enzyme, on the contrary, on average, by 23 % under the influence of the macroelements complex on winter wheat crops. There was an increase in the activity of AsAT by 41 % on average, and AlAT by 36.3 % with Avatarm-2 in winter wheat leaves. A decrease in the activity of both key enzymes of nitrogen metabolism under the influence of Avatarm-2-m complex was found, on average, by 27.2 % and 32.5 %, respectively, which indicates the stabilization of the metabolic direction of products and substrates by trace elements in the metabolic state of winter wheat leaf cells. Under the influence of Avatarm-2-st, there is a decrease in AlAT activity, on average 26.6 %, while the effect of succinate on the activity of AlAT was more significant – on average 48.3 %, because the biotechnological preparation Avatarm-2-st contains succinate, while Avatarm-2-m contains malic acid. AlAT reactions produce pyruvate, a key substrate of glucogenesis, whose increase can help activate the synthesis of carbohydrates necessary for plant growth. The enzymes AsAT and AlAT play a key role in the metabolism of aspartate, alanine, and glutamate, and the first two enzymes are used to form amides such as asparagine and glumamine, so increasing their activity is a condition for the accumulation of these amides as a reserve of NH4+. The concentration of NH3 under the influence of Avatarm-2 increased by 42 %, while under Avatarm-2-m and Avatarm-2-st the concentration did not change, indicating the regulatory effect of malate and succinate on the activation and degree of use of this form of Nitrogen in alternative processes of amino acid conversion. The chlorophyll content under the influence of LCP-macro increases, on average, by 2.8 times, under the influence of Avatarm-2- by 2.8 times, while the effect of acids in the composition of Avatarm-2-m and Avatarm-2-st is manifested differently, but the direction of decrease in this indicator relative to Avatarm-2 decreases, however, compared to the control, it increases this criterion, on average, by 1.9 and 1.7 times, respectively. It has been concluded that the optimization of nitrogen metabolism in winter wheat leaves under the action of chelated metal nanoparticles with organic acids malate and succinate at the critical stage of its organogenesis – tubing in the process of formation of productive winter wheat.

Widespread somatic L1 retrotransposition in normal colorectal epithelium

Throughout an individual’s lifetime, genomic alterations accumulate in somatic cells1–11. However, the mutational landscape induced by retrotransposition of long interspersed nuclear element-1 (L1), a widespread mobile element in the human genome12–14, is poorly understood in normal cells. Here we explored the whole-genome sequences of 899 single-cell clones established from three different cell types collected from 28 individuals. We identified 1,708 somatic L1 retrotransposition events that were enriched in colorectal epithelium and showed a positive relationship with age. Fingerprinting of source elements showed 34 retrotransposition-competent L1s. Multidimensional analysis demonstrated that (1) somatic L1 retrotranspositions occur from early embryogenesis at a substantial rate, (2) epigenetic on/off of a source element is preferentially determined in the early organogenesis stage, (3) retrotransposition-competent L1s with a lower population allele frequency have higher retrotransposition activity and (4) only a small fraction of L1 transcripts in the cytoplasm are finally retrotransposed in somatic cells. Analysis of matched cancers further suggested that somatic L1 retrotransposition rate is substantially increased during colorectal tumourigenesis. In summary, this study illustrates L1 retrotransposition-induced somatic mosaicism in normal cells and provides insights into the genomic and epigenomic regulation of transposable elements over the human lifetime.

Semilobar Holoprosencephaly Caused by a Novel and De Novo ZIC2 Pathogenic Variant.

Holoprosencephaly (HPE) is the most common embryonic forebrain developmental anomaly. It involves incomplete or absent division of the prosencephalon into two distinct cerebral hemispheres during the early stages of organogenesis. HPE is etiologically heterogeneous, and its clinical presentation is very variable. We report a case of a 7 month old female infant, diagnosed with non-syndromic semilobar holoprosencephaly, caused by a novel, de novo pathogenic variant in ZIC2 - one of the most commonly mutated genes in non-syndromic HPE coding for the ZIC2 transcription factor. The patient presented with microcephaly, mild facial dysmorphic features, central hypotonia and spasticity on all four extremities. Ultrasound imaging demonstrated the absence of septum pellucidum, semilobar fusion of the hemispheres and mega cisterna magna and brain MRI with confirmed the diagnosis of HPE. Early diagnosis and management are important for the prevention and treatment of complications associated with this condition.

The rat Downunder (Du) coat color mutation is associated with eye anomalies and embryonic lethality and maps to a 3.9-Mb region on chromosome 3.

Rodent coat color genes have been studied as a bioresource to understand developmental and cellular processes. The Downunder rat is a fancy variety with a marking on its belly that runs from the neck to the breech and appears to mirror the dorsal hooded marking. Here, we established a congenic strain carrying the Downunder (Du) gene in an F344 genetic background. In addition to the ventral marking, Du/+ rats exhibit anophthalmia or microphthalmia with incomplete penetrance. Du/Du embryos die in the early stages of organogenesis. Genetic linkage analysis mapped the Du gene to rat chromosome 3 and haplotype mapping with congenic rats localized the Du locus to a 3.9-Mb region. The Du locus includes two functional genes, glycosyltransferase-like domain-containing 1 (Gtdc1) and zinc finger E-box binding homeobox 2 (Zeb2). Although we found no functional variation within any of Zeb2's exons or intron-exon boundaries, Zeb2 mRNA levels were significantly lower in Du/+ rats compared with wild-type rats. It is known that melanocyte-specific Zeb2 deletion results in the congenital loss of hair pigmentation in mice. Taken together, our results indicate that the Du mutation exerts pleiotropic effects on hair pigmentation, eye morphology, and development. Moreover, the Zeb2 gene is a strong candidate for the Du mutation.

The effect of mung bean seedlings juice (<i>Vigna radiata (L.</i>) Wilczek.) on growth processes and protection against phytopathogens of spring wheat (<I>Triticum aestivum L.</I>) at early stages of organogenesis

Relevance. Mung bean is a new culture of versatile use for the Middle Volga region; it has a complex of valuable economic and biological properties. When studying seeds, seedlings and mung bean plants as raw materials for the pharmaceutical industry, it was revealed that this culture also has a biocidal effect on phytopathogens. The purpose of our research is to study the biological activity of the juice from the sprouts of mung bean on the seedlings of spring soft wheat for the subsequent creation of theoretical foundations for the development and use of mung bean as a growth stimulant and protection of wheat seedlings from phytopathogenic organisms.Methods. To obtain juice, three-day seedlings of mung bean of the Saltan variety were taken. Three varieties of spring soft wheat created at the Volga Research Institute of Breeding and Seed Production named after P.N. Konstantinov were used in the experiments — Kinelskaya 2020, Kinelskaya jubilee, Kinelskaya Zvezda.Results. The effect of juice from green and etiolated mung bean seedlings on phytopathogens and the growth of spring wheat seeds in the early stages of organogenesis was studied. It was found that the juice of green seedlings has a pronounced biocidal and stimulating activity. Thus, in the tested variants, the formation of primary roots exceeded the control by 15–26%, the length of primary roots exceeded the control by 248– 297% and the length of sprouts — by 337–403%. There were no signs of damage in all tested variants. In the juice of etiolated seedlings, such activity is less pronounced. Only at a concentration of cell juice of 1% in the studied wheat varieties, an excess over the control was observed: the formation of primary roots — by106–112%, the length of primary roots — by109–127% and the length of sprouts 108–125%. In other versions of this experiment, the results were ambiguous. The defeat of phytopathogens manifested itself, but the number of affected wheat seeds decreased as the concentration of cell juice solutions increased.

A Uterus-Inspired Niche Drives Blastocyst Development to the Early Organogenesis.

The fundamental physical features such as the mechanical properties and microstructures of the uterus need to be considered when building in vitro culture platforms to mimic the uterus for embryo implantation and further development but have long been neglected. Here, a uterus‐inspired niche (UN) constructed by grafting collagen gels onto polydimethylsiloxane based on a systematic investigation of a series of parameters (varying concentrations and thicknesses of collagen gel) is established to intrinsically specify and simulate the mechanics and microstructures of the mouse uterus. This brand‐new and unique system is robust in supporting embryo invasion, as evidenced by the special interaction between the embryos and the UN system and successfully promoting E3.5 embryo development into the early organogenesis stage. This platform serves as a powerful tool for developmental biology and tissue engineering.

ТАКТИКА ВЫБОРА ЭКСПЛАНТА ПРИ БИОТЕХНОЛОГИЧЕСКИХ ИССЛЕДОВАНИЯХ ЗАСУХОУСТОЙЧИВОСТИ ПШЕНИЦЫ МЕТОДОМ ЭМБРИОКУЛЬТУРЫ IN VITRO В СЕЛЕКЦИОННЫХ ЦЕЛЯХ

Drought is assessed as an unfavorable combination of meteorological conditions in which plants experience a long-term water shortage in the air and soil. One of the directions of experimental evaluation of plant drought resistance in vitro is to use embryos at one or another stage of development as explants (embryo culture in vitro). The prospects of this direction are determined mainly by the fact that the embryo has all the morphogenetic potentials of an adult organism (Батыгина, 2014), including the ability to withstand various stresses. In biotechnological studies using in vitro embryoculture, depending on the goals of a specific breeding program, it is important to carry out the right tactics for choosing an embryo as an explant at a certain stage of embryogenesis. It is the chosen stage of explant embryogenesis that determines which method the process of regenerant formation in vitro will follow: indirect (according to the scheme "one embryo → one callus → several regenerants") or direct (according to the scheme "one embryo → one regenerant"). Using the example of spring soft wheat, the article presents an overview of a number of literature and original data on the direction of biotechnological studies of drought resistance using the embryo culture in vitro method. The main attention is paid to the analysis of the structural features of wheat embryos at the early and middle stages of organogenesis associated with the induction of indirect and direct methods of formation of regenerants in embryo culture in vitro.

Initial material for breeding drought-resistant varieties of spring barley in the conditions of the Volga-Vyatka region

Water scarcity has a significant impact on plants, quality and quantity of crops. On the soils of the northeast of European Russia, instability of precipitation is one of the main factors negatively affecting barley productivity. To assess the drought tolerance level, we used the RSR (root-to-shoot ratio) indicator, which shows the relative redistribution of fluxes of plastic substances between root and aerial organs. Evaluation of 57 collection accessions of spring barley of various ecological and geographical origins was carried out. As a result of the research, sources of breeding of valuable traits were identified for further breeding work on the creation of barley varieties adaptive to the conditions of the Volga-Vyatka region. The accessions Bonita, Bionic, Cooper, Danuta, 752A, NCL 95098, local sample from India (k-3506), Odessky 115, Rodos, Kazminsky, Polarny 14, Adam, Bear, Medicum 11, Irbe (PR-3528), Mie, 121–13, and C-105 are characterized by resistance to osmotic stress at the early stages of organogenesis. For further breeding work drought-resistant varieties NCL 95098, Cooper, Bonita, Danuta, Mie, Rodos, Kazminsky, Adam, Bear, Medicum 11, Irbe (PR-3528), 752A, Polarny 14, and C-105, distinguished by the elements of plant productivity, are advisable to use taking into account their positive qualities. The rest of the drought-resistant accessions are recommended to be included in crosses with varieties having higher productivity.

Endosperm culture: a facile and efficient biotechnological tool to generate passion fruit (Passiflora cincinnata Mast.) triploid plants

Triploid plants represent an important resource for the breeding of fruit and ornamental plants. Here, we report a facile and robust system for regenerating passion fruit triploid plants (Passiflora cincinnata Mast.) through in vitro endosperm culture. We describe the histological and biochemical aspects associated with the de novo shoot organogenesis. Endosperms were cultured on Murashige and Skoog medium supplemented with 1.5, 2.0, and 3.0 mg L−1 of 6-benzyladenine or thidiazuron, while a cytokinin-free medium was used as control. The highest percentage of organogenic calli (56%) was estimated at 1.7 mg L−1 6-benzyladenine, whereas the highest average number of shoots (24.85) per explant was estimated at 1.6 mg L−1 6-benzyladenine. Flow cytometry and chromosomal analysis confirmed that endosperm-derived plants were triploid, with a chromosome count of 27 (2n = 3x = 27) as well as a DNA amount similar to that of endosperm and 1.5 times greater than in diploid counterparts (2n = 2x = 18). The regeneration of adventitious shoots was evident 30 days after culture and occurred from the reprogramming of edge cells of the endosperm. During this process, lipids and proteins were quickly mobilized in the early stages of shoot organogenesis, whereas carbohydrates were synthesized throughout the development of adventitious shoots. This observation illustrates the mobilization dynamics of endosperm reserves during de novo shoot organogenesis in P. cincinnata. Adventitious shoots induced by reprogramming of the outer cell layers of the endosperm generate true-to-type triploid passion fruit plants.

A caveolin binding motif in Na/K-ATPase is required for stem cell differentiation and organogenesis in mammals and C. elegans.

Several signaling events have been recognized as essential for regulating cell lineage specification and organogenesis in animals. We find that the gain of an amino-terminal caveolin binding motif (CBM) in the α subunit of the Na/K-adenosine triphosphatase (ATPase) (NKA) is required for the early stages of organogenesis in both mice and Caenorhabditis elegans. The evolutionary gain of the CBM occurred at the same time as the acquisition of the binding sites for Na+/K+. Loss of this CBM does not affect cell lineage specification or the initiation of organogenesis, but arrests further organ development. Mechanistically, this CBM is essential for the dynamic operation of Wnt and the timely up-regulation of transcriptional factors during organogenesis. These results indicate that the NKA was evolved as a dual functional protein that works in concert with Wnt as a hitherto unrecognized common mechanism to enable stem cell differentiation and organogenesis in multicellular organisms within the animal kingdom.

Young peacock-shaped plants need protection

Goal. Paulownia felines — Paulownia tomentosa L., a promising bioenergy crop for our country. In the early stages of organogenesis (juvenile and immature), young plants of the peacock sprout easily suppress weeds. Therefore, young plantations of such a promising bioenergy crop need reliable and effective protection against the adverse effects of weeds. Method. Weeding processes for young peacock plantations in the small field experiments were conducted in 2018—2019. on the experimental lands of the Yaltushk SSS IBEK and the Central Bank of NAAS The area of the plots is 36 m2, the area of the plot is 25 m2. Repeat studies — 4 times. Placement of sites is regular in two tiers. Seeds and young plants (seedlings) of Clone 112 were used for growing on the plots. Results and Discussion. Contamination of plantations was mixed. The records, carried out on 01.06, recorded the presence of seedlings of Echinochloa crus-galli (L.) Pal Beauv, Setaria glauca (L.) Pal.Beauv, Chenopodium album L., Sinapis arvensis L., Thlaspy arvense L., Polygonum scabrum Moench., mustard beetle, Polygonum convolvulus L, Solanum nigrum L. The number of weeds averaged 89.5 pcs/m2. The largest number of seedlings was recorded in millet rooster 12.4pcs/m2, mouse gray — 10.3 pcs/m2, white swans — 8.7 pcs/m2, bear­ded birch — 7.3 pcs/ m2, talaban field — 7.1 pcs/m2. By the third decade of August, their number had increased to 134.0 pieces/ m2. Conclusions. Under the conditions of co-vegetation of young peacock-planted plants with weeds, the height of their plants by the second decade of September averaged 23.6.cm. The height of crop plants that vegetated without adversely affecting the presence of weed plantations (4 consecutive manual weeding) averaged 63.8 cm or 2.7 times greater. Such a negative impact requires the implementation of protection measures for young plants.

Adamts18 deficiency in zebrafish embryo causes defective trunk angiogenesis and caudal vein plexus formation

ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin type I motifs) enzymes play an important role in various morphogenesis processes. To determine the functions of Adamts18 in the early stages of organogenesis, we created Adamts18 deficient zebrafish using morpholino antisense oligonucleotides (MO) to generate exon 3 skipped adamts18 mRNA transcripts. Results showed that Adamts18 deficiency in zebrafish embryos caused developmental defects, including expanded brain ventricle and hindbrain edema, eye defects, and accumulation of blood in the caudal vein. Adamts18 deficiency also led to impaired trunk angiogenesis and formation of the caudal vein plexus (CVP). Consequently, Adamts18 deficient zebrafish embryos exhibited incomplete formation of intersegment vessels (ISVs), disruption of the honeycomb structure of CVP, and reduced CVP area and loop number. Furthermore, Adamts18 deficiency resulted in impaired blood circulation in major trunk, caudal vein (CV), and common cardinal vein (CCV). These aberrant vascular phenotypes in mutant zebrafish embryos were shown to be associated with a decreased expression of multiple angiogenesis-related signaling genes, including slit/robo, dll4/Notch, cox2, and fgfr. These findings indicate the critical role of Adamts18 in the early stages of vascular network development.

Effects of antifreeze proteins on cryopreserved sterlet (Acipenser ruthenus) sperm motility variables and fertilization capacity

The effect of antifreeze proteins on sterlet, Acipenser ruthenus sperm motility variables and fertilization rate were investigated after cryopreservation. Two types of antifreeze proteins (AFPI or AFPIII) were used at concentrations of 0.1, 1, 10 and 100 μg/mL. The motility variables of fresh and cryopreserved sperm with and without addition of antifreeze proteins were evaluated by the Computer Assisted Semen Analyzer (CASA). The fertilization rate using about 200,000 spermatozoa per egg was evaluated after 54 h incubation at 17 °C during the early stage of organogenesis. The motility, curvilinear velocity and straight-line velocity of fresh sperm was 93 ± 5%, 128 ± 13 μm/s and 89 ± 9 μm/s, respectively. There was a significant decrease of sperm motility rate between fresh sperm and cryopreserved sperm with/without addition of antifreeze proteins. The greatest motility among thawed samples was in the sperm cryopreserved with 10 μg/mL of AFPI (56 ± 20%), however, these data were not different compared to the sperm without antifreeze proteins (49 ± 14%). No statistical variations were detected in curvilinear velocity nor straight-line velocity. The fertilization rate with fresh sperm was 67 ± 7%. No significant differences were detected in fertilization rate between fresh and cryopreserved spermatozoa with/without addition of antifreeze proteins, except the sperm cryopreserved with 100 μg/mL of AFPIII (39 ± 14%). Thus, it is concluded that addition of antifreeze proteins to cryopreservation medium do not improve nor have toxicity effects on the quality and fertilization capacity of sterlet sperm after thawing.

Cytomegalovirus Infection: The Neurodevelopmental Peptide Signatures.

HCMV infection may cause neurodevelopmental disorders, including intellectual disability, hearing loss, cortical malformations, and calcifications. Theorizing about the still unknown molecular basis of HCMV-related diseases, this study analyzes the peptide sharing between HCMV, strains AD169 and Merlin, and human proteins, searching for shared sequences that might lead to crossreactive autoimmune injuries in the brain during immune responses following HCMV infection. HCMV proteins were analyzed for peptides shared with the human proteome using the Pir Peptide Match resource. Numerous HCMV peptides (ranging from 9 to 13 mer in length) are disseminated through hundreds of human proteins. The peptide sharing mostly involves crucial neurodevelopmental antigens such as PITX3, implicated in the differentiation of meso-diencephalic dopaminergic neurons; SIX3, which controls proper anterioposterior patterning of the diencephalon and formation of the rostral diencephalon during forebrain development; and ZIC2, which plays a fundamental role in the early stage of organogenesis of the central nervous system. This study describes a HCMV vs human peptide overlap that may represent a crossreactive platform linking the pathologic sequelae of HCMV infection to the immune anti-HCMV response. The data could inform development of effective and safe immune therapeutic/preventive approaches against HCMV infections.

Two-step Approach to Explore Early- and Late-stages of Organ Formation in the Avian Model: The Thymus and Parathyroid Glands Organogenesis Paradigm.

The avian embryo, as an experimental model, has been of utmost importance for seminal discoveries in developmental biology. Among several approaches, the formation of quail-chicken chimeras and the use of the chorioallantoic membrane (CAM) to sustain the development of ectopic tissues date back to the last century. Nowadays, the combination of these classical techniques with recent in vitro methodologies offers novel prospects to further explore organ formation. Here we describe a two-step approach to study early- and late-stages of organogenesis. Briefly, the embryonic region containing the presumptive territory of the organ is isolated from quail embryos and grown in vitro in an organotypic system (up to 48 h). Cultured tissues are subsequently grafted onto the CAM of a chicken embryo. After 10 days of in ovo development, fully formed organs are obtained from grafted tissues. This method also allows the modulation of signaling pathways by the regular administration of pharmacological agents and tissue genetic manipulation throughout in vitro and in ovo developmental steps. Additionally, developing tissues can be collected at any time-window to analyze their gene-expression profile (using quantitative PCR (qPCR), microarrays, etc.) and morphology (assessed with conventional histology and immunochemistry). The described experimental procedure can be used as a tool to follow organ formation outside the avian embryo, from the early stages of organogenesis to fully formed and functional organs.

Echinococcus multilocularis (Cestoda, Cyclophyllidea, Taeniidae): origin, differentiation and functional ultrastructure of the oncospheral tegument and hook region membrane

Both the oncospheral tegument and the hook region membrane (HRM) of Echinococcus multilocularis hexacanths originate from a syncytial binucleate complex that appears in the early stage of morphogenesis and organogenesis of the hexacanth larva. The primordium of this binucleate complex forms a binucleate syncytial cap or “calotte” situated beneath the inner envelope at one pole of the developing embryo. During oncospheral differentiation, the binucleate perikaryon of the syncytial cap is sunk progressively deeper into the central part of the embryo, but remains always connected with the distal cytoplasm by a tendrillar cytoplasmic connection or bridge. Following migration or sinking of the binucleate perikaryon, numerous cytoplasmic vesicles appear in the distal cytoplasm. These vesicles fuse progressively together and form a single large cavity or lacuna. The walls of this cavity are becoming at this point the walls of two delaminated layers: (1) the distal anucleated cytoplasmic layer is transformed into the oncospheral tegument and (2) the proximal thin cytoplasmic layer is transformed into the “hook region membrane”. This delamination of the initially compact layer of distal cytoplasm into two layers seems to be closely associated with differentiation of oncospheral hooks, the elongating blades of which protrude progressively into a newly formed cavity. The pressure of hook blades on the hook region membrane appears to facilitate its further separation from the basal layer of distal cytoplasm which is transformed into the peripheral layer of oncospheral tegument. In the mature oncosphere, the surface of this peripheral layer forms a regular brush border of cytoplasmic processes or microvilli and represents the true body covering of the hexacanth. The very thin cytoplasmic connection between the peripheral layer of tegument and binucleate perikaryon appears only very seldom in the ultrathin sections as a narrow cytoplasmic strand and has a plasma membrane that is reinforced by a single row of cortical microtubules. The HRM covers only one pole of the oncosphere and is attached to the oncosphere surface. The HRM is clearly visible in the mature oncosphere and is draped over the hook blades, the sharp points of which are protected by moderately electron-dense caps. Comparison of the above morphology with that of TEM study of the tegument of adult cestodes shows a great similarity as well as homology in the body covering of both larval and adult cestodes.

Identification and fate mapping of the pancreatic mesenchyme

The murine pancreas buds from the ventral embryonic endoderm at approximately 8.75 dpc and a second pancreas bud emerges from the dorsal endoderm by 9.0 dpc. Although it is clear that secreted signals from adjacent mesoderm-derived sources are required for both the appropriate emergence and further refinement of the pancreatic endoderm, neither the exact signals nor the requisite tissue sources have been defined in mammalian systems. Herein we use DiI fate mapping of cultured murine embryos to identify the embryonic sources of both the early inductive and later condensed pancreatic mesenchyme. Despite being capable of supporting pancreas induction from dorsal endoderm in co-culture experiments, we find that in the context of the developing embryo, the dorsal aortae as well as the paraxial, intermediate, and lateral mesoderm derivatives only transiently associate with the dorsal pancreas bud, producing descendants that are decidedly anterior to the pancreas bud. Unlike these other mesoderm derivatives, the axial (notochord) descendants maintain association with the dorsal pre-pancreatic endoderm and early pancreas bud. This fate mapping data points to the notochord as the likely inductive source in vivo while also revealing dynamic morphogenetic movements displayed by individual mesodermal subtypes. Because none of the mesoderm examined above produced the pancreatic mesenchyme that condenses around the induced bud to support exocrine and endocrine differentiation, we also sought to identify the mesodermal origins of this mesenchyme. We identify a portion of the coelomic mesoderm that contributes to the condensed pancreatic mesenchyme. In conclusion, we identify a portion of the notochord as a likely source of the signals required to induce and maintain the early dorsal pancreas bud, demonstrate that the coelomic mesothelium contributes to the dorsal and ventral pancreatic mesenchyme, and provide insight into the dynamic morphological rearrangements of mesoderm-derived tissues during early organogenesis stages of mammalian development.

Neural Differentiation of Spheroids Derived from Human Induced Pluripotent Stem Cells-Mesenchymal Stem Cells Coculture.

Organoids, the condensed three-dimensional (3D) tissues emerged at the early stage of organogenesis, are a promising approach to regenerate functional and vascularized organ mimics. While incorporation of heterotypic cell types, such as human mesenchymal stem cells (hMSCs) and human induced pluripotent stem cells (hiPSCs)-derived neural progenitors aid neural organ development, the interactions of secreted factors during neurogenesis have not been well understood. The objective of this study is to investigate the impact of the composition and structure of 3D hybrid spheroids of hiPSCs and hMSCs on dorsal cortical differentiation and the secretion of extracellular matrices and trophic factors in vitro. The hybrid spheroids were formed at different hiPSC:hMSC ratios (100:0, 75:25, 50:50, 25:75, 0:100) using direct mixing or pre-hiPSC aggregation method, which generated dynamic spheroid structure. The cellular organization, proliferation, neural marker expression, and the secretion of extracellular matrix proteins and the cytokines were characterized. The incorporation of MSCs upregulated Nestin and β-tubulin III expression (the dorsal cortical identity was shown by Pax6 and TBR1 expression), matrix remodeling proteins, and the secretion of transforming growth factor-β1 and prostaglandin E2. This study indicates that the appropriate composition and structure of hiPSC-MSC spheroids promote neural differentiation and trophic factor and matrix secretion due to the heterotypic cell-cell interactions.

ZIC2 in Holoprosencephaly.

The ZIC2 transcription factor is one of the most commonly mutated genes in Holoprosencephaly (HPE) probands. HPE is a severe congenital defect of forebrain development which occurs when the cerebral hemispheres fail to separate during the early stages of organogenesis and is typically associated with mispatterning of the embryonic midline. Recent study of genotype-phenotype correlations in HPE cases has defined distinctive features of ZIC2-associated HPE presentation and genetics, revealing that ZIC2 mutation does not produce the craniofacial abnormalities generally thought to characterise HPE but leads to a range of non-forebrain phenotypes. Furthermore, the studies confirm the extent of ZIC2 allelic heterogeneity and that pathogenic variants of ZIC2 are associated with both classic and middle interhemispheric variant (MIHV) HPE which arise from defective ventral and dorsal forebrain patterning, respectively. An allelic series of mouse mutants has helped to delineate the cellular and molecular mechanisms by which one gene leads to defects in these related but distinct embryological processes.