The ascidian Ciona intestinalis is a model organism of developmental and evolutionary biology and may provide crucial clues concerning two fundamental matters, namely, how chordates originated from the putative deuterostome ancestor and how advanced chordates originated from the simplest chordates. In this paper, a whole-life-span culture of C. intestinalis was conducted. Fed with the diet combination of dry Spirulina, egg yolk, Dicrateria sp., edible yeast and weaning diet for shrimp, C. intestinalis grew up to average 59 mm and matured after 60 d cultivation. This culture process could be repeated using the artificially cultured mature ascidians as material. When the fertilized eggs were maintained under 10, 15, 20, 25 degrees C, they hatched within 30 h, 22 h, 16 h and 12 h 50 min respectively experiencing cleavage, blastulation, gastrulation, neurulation, tailbud stage and tadpole stage. The tadpole larvae were characterized as typical but simplified chordates because of their dorsal nerve cord, notochord and primordial brain. After 8 - 24 h freely swimming, the tadpole larvae settled on the substrates and metamorphosized within 1- 2 d into filter feeding sessile juvenile ascidians. In addition, unfertilized eggs were successfully dechorionated in filtered seawater containing 1% Tripsin, 0.25% EDTA at pH of 10.5 within 40 min. After fertilization, the dechorionated eggs developed well and hatched at normal hatching rate. In conclusion, this paper presented feasible methodology for rearing the tadpole larvae of C. intestinalis into sexual maturity under controlled conditions and detailed observations on the embryogenesis of the laboratory cultured ascidians, which will facilitate developmental and genetic research using this model system.
Animals ; Ciona intestinalis ; growth & development ; Embryonic Development ; physiology ; Female ; Male ; Metamorphosis, Biological ; physiology ; Zygote ; growth & development

To understand how the nervous system develops from a small pool of progenitors during early embryonic development, it is fundamentally important to identify the diversity of neuronal subtypes, decode the origin of neuronal diversity, and uncover the principles governing neuronal specification across different regions. Recent single-cell analyses have systematically identified neuronal diversity at unprecedented scale and speed, leaving the deconstruction of spatiotemporal mechanisms for generating neuronal diversity an imperative and paramount challenge. In this review, we highlight three distinct strategies deployed by neural progenitors to produce diverse neuronal subtypes, including predetermined, stochastic, and cascade diversifying models, and elaborate how these strategies are implemented in distinct regions such as the neocortex, spinal cord, retina, and hypothalamus. Importantly, the identity of neural progenitors is defined by their spatial position and temporal patterning factors, and each type of progenitor cell gives rise to distinguishable cohorts of neuronal subtypes. Microenvironmental cues, spontaneous activity, and connectional pattern further reshape and diversify the fate of unspecialized neurons in particular regions. The illumination of how neuronal diversity is generated will pave the way for producing specific brain organoids to model human disease and desired neuronal subtypes for cell therapy, as well as understanding the organization of functional neural circuits and the evolution of the nervous system.
Humans ; Neural Stem Cells/physiology* ; Neurons/physiology* ; Brain ; Spinal Cord ; Embryonic Development ; Cell Differentiation/physiology*

The objectives of the present study were to compare the in vitro maturation (IVM), fertilization and early embryonic development of bovine oocytes recovered from ovaries during the follicular, metestrus and diestrus stages of the estrous cycle and at anestrus and pregnancy after maturation in a serum free culture medium. Cumulus oocyte complexes (COCs) collected from ovaries at different reproductive statuses were matured in medium 199 supplemented with 10 g/ml FSH, 10 g/ml LH, 1.5 g/m estradiol, 75 g/ml streptomycin, 100 IU/ml penicillin and 10 mM HEPES. COCs were incubated in 200 microliter droplets of maturation medium 199 under oil for 24 h at 39degrees c and 5% CO2. Matured oocytes were exposed to frozen-thawed TALP swim up, heparin capacitated sperm from two bulls separately in each replicate (20 h, 39C, 5% CO2). After fertilization, the presumptive zygotes were cultured in medium 199 containing 8 mg/ml BSA-V, 100 IU/ml penicillin-G, 75 g/ml streptomycin and 10 mM HEPES for 144 h at 39C and 5% CO2 without medium freshening or change. Oocytes/embryos were fixed, stained with DAPI and evaluated under fluorescent microscope. The IVM rates were almost similar among oocytes from all reproductive statuses (range: 89.8 to 95.4%). However, IVM rates for oocytes from the metestrus (90.6%) and pregnant (89.9%) phases were lower than the other groups. The fertilization rates were lower (p<0.05) for oocytes from the diestrus phase (72.4%) than from the other phases (range: 81.1 to 86.6%). Oocytes, recovered during the metestrus phase of the estrous cycle, resulted in the highest cleavage rate (60.0%), while oocytes from the diestrus phase had the poorest embryonic development (39.8%: p<0.05). Majority of the embryos from all reproductive phases showed a developmental arrest around 8-cell stage. Although the developmental competence of oocytes from pregnant and anestrus animals was lower than that from the other reproductive stages, they could be potentially used as oocyte donors. Long term, in vitro embryo culture without medium freshening or change was hypothesized to have caused the failure to overcome the 8-cell block to development.
Animals ; Cattle/*embryology/*physiology ; Ectogenesis/physiology ; Embryonic and Fetal Development ; Estrous Cycle/*physiology ; Female ; Fertilization in Vitro ; Male ; Oocytes/*growth&development/*physiology ; Pregnancy

Undifferentiated embryonic stem (ES) cells can be maintained in vitro if cultured in the presence of the cytokine leukaemia inhibitory factor (LIF). ES cells can also differentiate in vitro. A particularly efficient method for inducing ES cell differentiation is to culture ES cells as aggregates in the absence of LIF. Under these conditions they form structures known as embryoid bodies (EBs). However the current protocols for EB formation are still diverse. In order to facilitate further study, we carefully controlled the culture conditions for EB formation, and here we report an efficient protocol by which uniformly differentiated EBs were obtained, monitored by measuring the differentiation of beating cardiomyocytes. Furthermore, by using this protocol we observed in long-term cultured plating EBs (> 60 days) there still exist cell colony with pluripotency. This observation raised a potential possibility that ES cells may keep pluripotent in a niche provided by differentiated cells.
Animals ; Cell Differentiation ; physiology ; Cells, Cultured ; Culture Media ; Embryonic Development ; physiology ; Embryonic Stem Cells ; cytology ; Leukemia Inhibitory Factor ; pharmacology ; Mice ; Stem Cell Niche ; physiology ; Time Factors

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder, with multiple genetic and environmental risk factors. The interplay between genetic and environmental factors has become the subject of intensified research in the last several years. Vitamin D deficiency has recently been proposed as a possible environmental risk factor for ASD. Vitamin D has a unique role in brain homeostasis, embryogenesis and neurodevelopment, immunological modulation (including the brain's immune system), antioxidation, antiapoptosis, neural differentiation and gene regulation. Children with ASD had significantly lower serum levels of 25-hydroxy vitamin D than healthy children.Therefore vitamin D deficiency during pregnancy and early childhood may be an environmental trigger for ASD.
Child Development Disorders, Pervasive ; etiology ; genetics ; Embryonic Development ; Homeostasis ; Humans ; Vitamin D ; physiology ; Vitamin D Deficiency ; complications

Protein kinase C (PKC) family plays a critical role in many developmental events, including oocyte activation, completion of the second meiosis and initiation of the first mitosis, compaction, and blastocysts formation as well. But little is known of its many isozymes. Studies have shown that 10 isozymes of PKC and its anchor protein, RACK, are expressed in the course from 2 cell stage through blastocyst stage in mouse. We reviewed here the recent studies on the location pattern and expression levels of different PKC isozymes. Those studies indicated that the isozymes were very important for every stage of preimplantation embryonic development, especially at the early 4-cell stage. Some are increased temporarily in nucleus, which indicated that they might control and regulate the remolding of embryonic nucleus. We also analyzed the possible functions of PKCs in the somatic nuclear transferred embryos.
Animals ; Embryonic Development ; physiology ; Fertilization ; physiology ; Isoenzymes ; metabolism ; physiology ; Oocytes ; physiology ; Protein Kinase C ; metabolism ; physiology ; Receptors for Activated C Kinase ; Receptors, Cell Surface ; metabolism

Salivary glands provide saliva to maintain oral health, and a loss of salivary gland function substantially decreases quality-of-life. Understanding the biological mechanisms that generate salivary glands during embryonic development may identify novel ways to regenerate function or design artificial salivary glands. This review article summarizes current research on the process of branching morphogenesis of salivary glands, which creates gland structure during development. We highlight exciting new advances and opportunities in studies of cell-cell interactions, mechanical forces, growth factors, and gene expression patterns to improve our understanding of this important process.
Animals ; Cell Communication ; physiology ; Embryonic Development ; physiology ; Epithelium ; embryology ; Extracellular Matrix ; physiology ; Humans ; Intercellular Signaling Peptides and Proteins ; physiology ; Morphogenesis ; physiology ; Salivary Glands ; embryology

Mammalian oocyte maturation and early embryo development processes are Ca(2+)-dependent. In this study, we used confocal microscopy to investigate the distribution pattern of Ca2+ and its dynamic changes in the processes of bovine oocytes maturation, in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) embryo development. During the germinal vesicle (GV) and GV breakdown stage, Ca2+ was distributed in the cortical ooplasm and throughout the oocytes from the MI to MII stage. In IVF embryos, Ca2+ was distributed in the cortical ooplasm before the formation of the pronucleus. In 4-8 cell embryos and morulas, Ca2+ was present throughout the blastomere. In PA embryos, Ca2+ was distributed throughout the blastomere at 48 h, similar to in the 4-cell and 8-cell phase and the morula. At 6 h after activation, there was almost no distribution of Ca2+ in the SCNT embryos. However, Ca2+ was distributed in the donor nucleus at 10 h and it was distributed throughout the blastomere in the 2-8 cell embryos. In this study, Ca2+ showed significant fluctuations with regularity of IVF and SCNT groups, but PA did not. Systematic investigation of the Ca2+ location and distribution changes during oocyte maturation and early embryo development processes should facilitate a better understanding of the mechanisms involved in oocyte maturation, reconstructed embryo activation and development, ultimately improving the reconstructed embryo development rate.
Aniline Compounds/chemistry ; Animals ; Calcium/*physiology ; Cattle/*physiology ; Embryonic Development/*physiology ; Female ; Fertilization in Vitro/*veterinary ; Microscopy, Confocal/veterinary ; Oocytes/*physiology ; Parthenogenesis/*physiology ; Xanthenes/chemistry

OBJECTIVETo compare the development of abnormal pronuclear zygotes after intracytoplasmic sperm injection (ICSI) and analyze their genetic polymorphism.

METHODSFour hundred and ninety three abnormal pronuclear zygotes after ICSI were divided into three groups based on the number of pronuclei: 347 nonpronuclear oocytes, 71 monopronuclear zygotes and 75 multipronuclear zygotes. All of them were cultured in the medium of Vitrolife G5 series(TM). Sixteen short tandem repeats (STR) of seven blastocysts were then analyzed by ABI3100.

RESULTSThe cleavage rate of nonpronuclear group (25.4%) was lower than that of the others (P<0.01), the proportion of blocked embryos in nonpronuclear group (48.9%) was significantly higher than that of the others (P<0.05), but the blastocyst rate showed no significant difference in three groups (P>0.05). The genetic polymorphism of the 16 STRs showed that the blastocysts from the nonpronuclear and multipronuclear were diploid, and one of the blastocysts from nonpronuclear oocyte was Y-bearing.

CONCLUSIONThe zygotes with abnormal pronuclei after ICSI might have development potential, and the blastocysts from nonpronuclear oocytes and multipronuclear zygotes could be diploid.

Blastocyst ; physiology ; Cell Nucleus ; physiology ; Embryonic Development ; genetics ; physiology ; Female ; Fertilization in Vitro ; adverse effects ; Humans ; Male ; Oocytes ; physiology ; Sperm Injections, Intracytoplasmic ; adverse effects ; Tandem Repeat Sequences ; Zygote ; physiology

Spermatogenesis is a process consisting of spermatogonial proliferation, spermatocytic meiosis, and spermiogenesis, and is also considered to be a process in which heterochromatins gradually aggregate and finally reach a highly condensed formation in the sperm head. Recent studies show that epigenetic regulation plays a key role in spermatogenesis. This review discusses the mechanisms of epigenetic regulation in spermatogenesis in three aspects, DNA methylation, histone modification, and noncoding RNAs. These factors are essential for spermatogenesis, fertilization, and embryogenesis by mutual regulation as well as by gene expression regulation, transposon activation, sex chromosome inactivation, and genome imprinting.
DNA Methylation ; Embryonic Development ; Epigenesis, Genetic ; physiology ; Genomic Imprinting ; Humans ; Male ; Meiosis ; Spermatogenesis ; genetics ; Spermatogonia ; cytology ; physiology