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Developmental Biology Apr 2019Tadpole larvae of the ascidian, Halocynthia roretzi, show morphological left-right asymmetry in the brain structures and the orientation of tail bending within the...
Tadpole larvae of the ascidian, Halocynthia roretzi, show morphological left-right asymmetry in the brain structures and the orientation of tail bending within the vitelline membrane. Neurula embryos rotate along the anterior-posterior axis in a counterclockwise direction, and then this rotation stops when the left side of the embryo is oriented downwards. Contact of the left-side epidermis with the vitelline membrane promotes nodal gene expression in the left-side epidermis. This is a novel mechanism in which rotation of whole embryos provides the initial cue for breaking left-right symmetry. Here we show that epidermal monocilia, which appear at the neurula rotation stage, generate the driving force for rotation. A ciliary protein, Arl13b, fused with Venus YFP was used for live imaging of ciliary movements. Although overexpression of wild-type Arl13b fusion protein resulted in aberrant movements of the cilia and abrogation of neurula rotation, mutant Arl13b fusion protein, in which the GTPase and coiled-coil domains were removed, did not affect the normal ciliary movements and neurula rotation. Epidermis cilia moved in a wavy and serpentine way like sperm flagella but not in a rotational way or beating way with effective stroke and recovery stroke. They moved very slowly, at 1/7 Hz, consistent with the low angular velocity of neurula rotation (ca. 43°/min). The tips of most cilia pointed in the opposite direction of embryonic rotation. Similar motility was also observed in Ciona robusta embryos. When embryos were treated with a dynein inhibitor, Ciliobrevin D, both ciliary movements and neurula rotation were abrogated, showing that ciliary movements drive neurula rotation in Halocynthia. The drug also inhibited Ciona neurula rotation. Our observations suggest that the driving force of rotation is generated using the vitelline membrane as a substrate but not by making a water current around the embryo. It is of evolutionary interest that ascidians use ciliary movements to break embryonic left-right symmetry, like in many vertebrates. Meanwhile, ascidian embryos rotate as a whole, similar to embryos of non-vertebrate deuterostomes, such as echinoderm, hemichordate, and amphioxus, while swimming.
Topics: Animals; Body Patterning; Cilia; Dyneins; Embryo, Mammalian; Epidermis; Movement; Recombinant Fusion Proteins; Rotation; Urochordata
PubMed: 30059669
DOI: 10.1016/j.ydbio.2018.07.023 -
Zygote (Cambridge, England) Oct 2022Ascidians (Urochordate) are hermaphroditic marine invertebrates that release sperm and eggs to the surrounding seawater. However, several ascidians, including and show...
Ascidians (Urochordate) are hermaphroditic marine invertebrates that release sperm and eggs to the surrounding seawater. However, several ascidians, including and show strict self-sterility due to a self/nonself-recognition mechanism in the interaction between sperm and the vitelline coat (VC) of the eggs. We have previously reported that sperm intracellular Ca level drastically increased immediately after sperm binding to the VC of self eggs but not nonself eggs in type A, which was potently inhibited by lowering the external Ca concentration, suggesting that sperm Ca influx occurs after sperm self-recognition on the VC. Here, we investigated whether self-sterility was abolished by lowering the external Ca concentration in The results showed that the block to self-fertilization was removed by low-Ca (∼1 mM) seawater without decreasing the fertilization rate. Such an effect was not observed with Mg or K. These results led us to conclude that a low-Ca environment is sufficient to block the self-recognition signal upon fertilization. As low-Ca seawater showed no effect on self-sterility, we propose that the mechanism of self-sterility in must be distinctive from that in .
Topics: Animals; Calcium; Ciona intestinalis; Fertilization; Infertility; Male; Seawater; Self-Fertilization; Semen; Spermatozoa; Urochordata; Vitelline Membrane
PubMed: 35686329
DOI: 10.1017/S0967199422000144 -
Biomolecules Nov 2023Immature starfish oocytes isolated from the ovary are susceptible to polyspermy due to the structural organization of the vitelline layer covering the oocyte plasma...
Immature starfish oocytes isolated from the ovary are susceptible to polyspermy due to the structural organization of the vitelline layer covering the oocyte plasma membrane, as well as the distribution and biochemical properties of the actin cytoskeleton of the oocyte cortex. After the resumption of the meiotic cycle of the oocyte triggered by the hormone 1-methyladenine, the maturing oocyte reaches fertilizable conditions to be stimulated by only one sperm with a normal Ca response and cortical reaction. This cytoplasmic ripening of the oocyte, resulting in normal fertilization and development, is due to the remodeling of the cortical actin cytoskeleton and germinal vesicle breakdown (GVBD). Since disulfide-reducing agents such as dithiothreitol (DTT) are known to induce the maturation and GVBD of oocytes in many species of starfish, we analyzed the pattern of the fertilization response displayed by oocytes pre-exposed to DTT with or without 1-MA stimulation. Short treatment of immature oocytes with DTT reduced the rate of polyspermic fertilization and altered the sperm-induced Ca response by changing the morphology of microvilli, cortical granules, and biochemical properties of the cortical F-actin. At variance with 1-MA, the DTT treatment of immature starfish oocytes for 70 min did not induce GVBD. On the other hand, the DTT treatment caused an alteration in microvilli morphology and a drastic depolymerization of the cortical F-actin, which impaired the sperm-induced Ca response at fertilization and the subsequent embryonic development.
Topics: Animals; Female; Male; Starfish; Dithiothreitol; Actins; Semen; Oocytes; Fertilization
PubMed: 38002342
DOI: 10.3390/biom13111659 -
Nature Aug 2019Tissue morphogenesis arises from coordinated changes in cell shape driven by actomyosin contractions. Patterns of gene expression regionalize cell behaviours by...
Tissue morphogenesis arises from coordinated changes in cell shape driven by actomyosin contractions. Patterns of gene expression regionalize cell behaviours by controlling actomyosin contractility. Here we report two modes of control over Rho1 and myosin II (MyoII) activation in the Drosophila endoderm. First, Rho1-MyoII are induced in a spatially restricted primordium via localized transcription of the G-protein-coupled receptor ligand Fog. Second, a tissue-scale wave of Rho1-MyoII activation and cell invagination progresses anteriorly away from the primordium. The wave does not require sustained gene transcription, and is not governed by regulated Fog delivery. Instead, MyoII inhibition blocks Rho1 activation and propagation, revealing a mechanical feedback driven by MyoII. We find that MyoII activation and invagination in each row of cells drives adhesion to the vitelline membrane mediated by integrins, apical spreading, MyoII activation and invagination in the next row. Endoderm morphogenesis thus emerges from local transcriptional initiation and a mechanically driven cycle of cell deformation.
Topics: Animals; Cell Adhesion; Cell Shape; Drosophila Proteins; Drosophila melanogaster; Endoderm; Integrins; Morphogenesis; Myosin Type II; Transcriptional Activation; Vitelline Membrane; rho GTP-Binding Proteins
PubMed: 31413363
DOI: 10.1038/s41586-019-1492-9 -
Journal of Morphology Sep 2023Ovarian follicles of sterlets (Acipenser ruthenus) are composed of a single oocyte surrounded by follicular cells (FCs), basal lamina, and thecal cells. Previtellogenic...
Asymmetry in previtellogenic and early vitellogenic oocytes, ultrastructure of follicular cells and egg envelope in the pigmented sterlet, Acipenser ruthenus L. 1758 (Chondrostei, Acipenseriformes).
Ovarian follicles of sterlets (Acipenser ruthenus) are composed of a single oocyte surrounded by follicular cells (FCs), basal lamina, and thecal cells. Previtellogenic oocytes are polarized. Homogeneous ooplasm (contains ribosomes) and granular ooplasm (comprises nuage aggregations of nuclear origin, rough endoplasmic reticulum (RER), Golgi complexes, ribosomes, and mitochondria) are distinguished. Granular ooplasm is initially located near the nucleus, contacts the plasma membrane of the oocyte (oolemma) and forms a thin layer underneath its entire perimeter. Next, a ring that surrounds the nucleus is formed and sends strands directed toward the oolemma. The lipid body composed of lipid droplets forms adjacent to this ring. Later, the granular ooplasm and strands enlarge toward the oolemma, lipid body disperses, and homogeneous ooplasm is no longer present. A thin cortical ooplasm is formed underneath the oolemma and does not contain any organelles. The oocyte nucleus moves to the center. The nucleoplasm contains lampbrush chromosomes, nuclear bodies, and multiple nucleoli. Early vitellogenic oocytes are polarized, too. Three regions in the ooplasm are distinguished: the perinuclear (contains lipid droplets near the nuclear envelope), the endoplasm (contains yolk platelets and lipid droplets), and the periplasm (contains yolk spheres, pigment granules, and microtubules). In all these regions the RER, Golgi complexes, nuage, and mitochondria are present. Micropinocytotic vesicles, Golgi vesicles and precursors of the internal layer of the egg envelope are in the cortical ooplasm. Some FCs delaminate from the follicular epithelium, degenerate and vesicles are released into the perioocytic space. They may contain precursors of egg envelope and may be involved in "cell-cell" communication. The egg envelope (zona radiata, zona pellucida) is made up of three layers: the vitelline envelope (inner layer), the middle layer, and the outer layer. In its deposition, both the oocyte and FCs are engaged.
Topics: Female; Animals; Oocytes; Ovarian Follicle; Fishes; Cytoplasm; Vitellogenesis
PubMed: 37585228
DOI: 10.1002/jmor.21631 -
Poultry Science Feb 2024The study aimed to analyze the biological value of eggs and extra-embryonic structures affecting pheasant hatchability depending on the eggshell's color. Eggs (1,415)...
The study aimed to analyze the biological value of eggs and extra-embryonic structures affecting pheasant hatchability depending on the eggshell's color. Eggs (1,415) from 62-wk-old pheasants were used. The quality of fresh blue (BL), brown (BR), and green (G) eggs were analyzed. Incubation lasted for 25 d. Thick albumen (d 0, 1, 7, 14), amniotic fluid (d 14, 18), and the yolk (d 0-14) were collected. The pH, viscosity, lysozyme activity, crude protein (CP) content in albumen and amnion, pH, vitelline membrane strength, and fatty acids (FA) content in the yolk were performed. The lowest hatchability was in the BL group, and the highest was in the G group. BL group showed lower eggshell thickness and strength and higher egg weight. In thick albumen and amniotic fluid, the pH decreased with the incubation. In the yolk, there was an increasing trend (P = 0.015), with a decrease on d 18 (P < 0.001). The vitelline membrane strength decreased after 1 d of incubation, excluding BR eggs (P < 0.001). Thick albumen viscosity was higher on d 14 in the G group than in other dates and groups, the lowest in amniotic fluid, and slightly higher in BL and BR eggs. On d 18, amniotic fluid viscosity increased (P < 0.001). The lowest viscosity was indicated in BL eggs (P < 0.001). The lysozyme activity in thick albumen on d 14 was the highest (uniquely in BR and G groups), and the lowest values were found in amniotic fluid on d 14; after four d, the activity increased (P < 0.001). The CP content was higher in the BL group on d 14. In amnion, on d 14, the CP content was the lowest (<1%) and increased on d 18 (P < 0.001). There was a higher FA content (especially UFA) in the G group and a decrease in FA content after d 14 (P < 0.001). It was found that eggs with green eggshells have the highest biological value, and blue eggs are the least useful for incubation.
Topics: Animals; Chickens; Egg Shell; Muramidase; Ovum; Meat; Albumins; Quail; Fatty Acids; Eggs; Egg Yolk
PubMed: 38134460
DOI: 10.1016/j.psj.2023.103338 -
Methods in Molecular Biology (Clifton,... 2019This chapter provides an ImageJ/Fiji automated macro approach to remove the vitelline membrane autofluorescence in live Drosophila embryo movies acquired in a 4D (3D...
This chapter provides an ImageJ/Fiji automated macro approach to remove the vitelline membrane autofluorescence in live Drosophila embryo movies acquired in a 4D (3D plus time) fashion. The procedure consists in a segmentation pipeline that can cope with different relative intensities of the vitelline membrane autofluorescence, followed by a developed algorithm that adjusts the extracted outline selection to the shape deformations that naturally occur during Drosophila embryo development. Finally, the fitted selection is used to clear the external glowing halo that, otherwise, would obscure the visualization of the internal embryo labeling upon projection or 3D rendering.
Topics: Animals; Animals, Genetically Modified; Artifacts; Drosophila; Drosophila Proteins; Embryo, Nonmammalian; Embryonic Development; Fluorescence; Green Fluorescent Proteins; Imaging, Three-Dimensional; Intravital Microscopy; Microscopy, Fluorescence; Video Recording; Vitelline Membrane
PubMed: 31432480
DOI: 10.1007/978-1-4939-9686-5_9 -
Poultry Science Jun 2023The study aimed to assess various quality characteristics (physical, morphologic, mechanical) of hatching eggs during the early-mid incubation period. Hatching eggs...
The study aimed to assess various quality characteristics (physical, morphologic, mechanical) of hatching eggs during the early-mid incubation period. Hatching eggs (1,200) were bought from a broiler Ross 308 breeder flock. Before incubation, 20 eggs were analyzed for dimensions and morphologic composition. Eggs (1,176) were incubated for 21 d. Hatchability was analyzed. On d 1, 2, 4, 6, 8, 10, and 12, eggs were collected (n = 20). The eggshell surface temperature and water loss were measured. The eggshell strength and thickness and the vitelline membrane strength were analyzed. The pH of thick albumen, amniotic fluid, and yolk were determined. The viscosity and lysozyme activity were studied for the thick albumen and amniotic fluid. Water loss was proportional and significantly different between incubation days. The yolk vitelline membrane strength highly depended on incubation days, decreasing steadily within the first 2 d (R = 0.9643). The albumen pH decreased from d 4 till d 12 of incubation, whereas the yolk pH first increased from d 0 to d 2 before a decline on d 4. Albumen viscosity was highest on d 6. There was a strong dependence of viscosity decrease with increasing shear rate (R = 0.7976). On the first day of incubation, the highest lysozyme hydrolytic activity was demonstrated (33,790 U/mL) compared to the activity from the amniotic fluid (8-12 d). From d 6, lysozyme activity decreased to 70 U/mL (d 10). On d 12, amniotic fluid lysozyme activity increased by over 6,000 U/mL compared to d 10. The lysozyme hydrolytic activity was lower in the amniotic fluid (d 8-12) compared to the thick albumen (0-6 d) (P < 0.001). The embryo's protective barriers are changed, and the fractions are hydrated during incubation. It could be concluded that the lysozyme is transferred from the albumen to the amniotic fluid due to its activity.
Topics: Animals; Chickens; Muramidase; Ovum; Albumins; Egg Shell
PubMed: 37116284
DOI: 10.1016/j.psj.2023.102689 -
Animals : An Open Access Journal From... Feb 2023This study evaluates the effect of housing environment on the egg quality characteristics of brown egg layers as many different environments are currently used in the...
This study evaluates the effect of housing environment on the egg quality characteristics of brown egg layers as many different environments are currently used in the industry. Battery cages, barren colony cages, enriched colony cages, cage-free, and free-range environments were evaluated. Overall, all egg quality measurements were affected by housing environment ( < 0.01) except for vitelline membrane strength, elasticity, and egg solids. Eggshells and yolks were lightest in barren colony cages and darkest from free-range hens ( < 0.0001). Free-range eggs were heavier than eggs from all other environments ( < 0.0001). Cage-free eggs had lower albumen height and Haugh units than other environments ( < 0.0001). Lastly, cage-free and free-range eggs had stronger eggshells than the other environments ( < 0.0001), and free-range eggs had more elastic eggshells than eggs from conventional battery cages and barren colony cages ( < 0.01). Access to the range seemed to give free-range hens different nutritional advantages, which allowed for the darker yolks and shells. Furthermore, eggs from barren colony cages seemed to exhibit more negative characteristics. Simply adding enrichments to colony cages did not improve or detract from egg quality. From this research, it appears that, as the industry moves toward extensive environments, the egg quality of brown egg layers will improve.
PubMed: 36830504
DOI: 10.3390/ani13040716 -
Comparative Biochemistry and... Apr 2020Cyclophosphamide (CPA) is an alkylating agent used for cancer chemotherapy, organ transplantation, and autoimmune disease treatment. Here, mRNA sequencing and...
Cyclophosphamide (CPA) is an alkylating agent used for cancer chemotherapy, organ transplantation, and autoimmune disease treatment. Here, mRNA sequencing and high-resolution respirometry were performed to evaluate the alterations of Drosophila melanogaster gene expression fed with CPA under acute (0.1 mg/mL, for 24 h) and chronic (0.05 mg/mL, for 35 days) treatments. Differential expression analysis was performed using Cufflinks-Cuffdiff, DESeq2, and edgeR software. CPA affected genes are involved in several biological functions, including stress response and immune-related pathways, oxi-reduction and apoptotic processes, and cuticle and vitelline membrane formation. In particular, this is the first report of CPA-induced mitochondrial dysfunction caused by the downregulation of genes involved with mitochondria constituents. CPA treatment also changed the transcription pattern of transposable elements (TEs) from the gypsy and copia superfamilies. The results presented here provided evidence of CPA mitochondrial toxicity mechanisms and that CPA can modify TEs transcription in Drosophila flies.
Topics: Animals; Apoptosis; Cyclophosphamide; DNA Transposable Elements; Drosophila Proteins; Drosophila melanogaster; Gene Expression; Mitochondria; Oxidation-Reduction; Peptide Hydrolases; Retroelements
PubMed: 31982542
DOI: 10.1016/j.cbpc.2020.108718