scholarly journals Structural analysis of the Pimelodus maculatus (Lacépède, 1803) embryogenesis (Siluriformes: Pimelodidae)

2011 ◽  
Vol 9 (3) ◽  
pp. 601-616 ◽  
Author(s):  
Hellen Buzollo ◽  
Rosicleire Veríssimo-Silveira ◽  
Isângela R. Oliveira-Almeida ◽  
Juliana S. Alexandre ◽  
Hélio T. Okuda ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Cleavage Pattern ◽  
Posterior Intestine ◽  
Gelatinous Layer ◽  
Eyes Closed ◽  
Mean Diameter ◽  
Survival Studies ◽  
Otic Vesicles ◽  
Pimelodus Maculatus ◽  
Duration Of Development

The fish embryonic development comprises the events between the egg fertilization up to larvae hatching, being useful for the identification of viable eggs in productivity and survival studies as well as in raising experiments of several species. The goal of the present study was to characterize the embryonic development of Pimelodus maculatus (Siluriformes; Pimelodidae). The embryogenesis was typical of teleosteans, but with differences in relation to other species such as duration of development, type of blastocoel, moment of somite segmentation among others. Six stages of embryonic development were defined: zygote, cleavage, blastula, gastrula, organogenesis (divided in phases: early segmentation and late segmentation) and hatching with a period of incubation equal to 13 hours at 29 ºC and 17 hours at 25 ºC. The extruded oocytes presented a mean diameter of 812 µm before and 1066 µm after hydration. When fertilized, they presented a yellowish coloration and a gelatinous layer surrounding the chorion. The cleavage pattern is described as: 2; 4; 8 (4x2); 16 (4x4); 32 (4x8) and 64 (2x4x8) blastomeres up to morula phase (+64 cells). It was also possible to observe at this phase, the beginning of the formation of the yolk syncyctial layer (YSL). Afterwards, the blastula and gastrula stages followed. The end of gastrula was characterized by the formation of the yolk plug. Subsequently, the differentiation between cephalic and caudal regions began, along with the embryo elongation, structuring of optic, Kupffer's and otic vesicles besides a previously unidentified structure in the yolk syncyctial layer. The end of this stage is typified by the tail detachment. The late segmentation phase was distinguished by a free tail, presence of more than 30 somites, optic and otic vesicles, development of posterior intestine, pigmentation of cephalic and caudal regions of yolk sac and embryo growth. The recently-hatched larvae presented a primordial digestive tract, quite evident and pigmented eyes, closed mouth, encephalic vesicles and a mean length of 3410 µm.

scholarly journals Observation of the embryonic development in Pseudoplatystoma coruscans (Siluriformes: Pimelodidae) under light and scanning electron microscopy

Zygote ◽  
2008 ◽  
Vol 16 (4) ◽  
pp. 333-342 ◽  
Author(s):  
Camila Marques ◽  
Laura Satiko Okada Nakaghi ◽  
Francine Faustino ◽  
Luciana Nakaghi Ganeco ◽  
José Augusto Senhorini
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Embryonic Development ◽  
Tropical Fish ◽  
Egg Cell ◽  
Development Stages ◽  
Cell Cleavage ◽  
Mean Diameter ◽  
Morula Stage ◽  
Scanning Electron

SummaryPseudoplatystoma coruscans is a very popular species for tropical fish culture as it has boneless meat of delicate taste and firm texture. Few studies on fish reproductive biology refer to the morphological features of eggs. The goal, therefore, of this present work was to perform a structural and ultrastructural analysis of fertilization and embryonic development in P. coruscans. The incubation period, from fertilization to hatching, lasts 13 h at 28/29 °C and 18 h at 27 °C. The oocytes had a mean diameter of 0.95 mm and hatched larvae were 2.55 mm in diameter. Analysing their development, we observed round, yellow oocytes that bore a double chorion membrane and a single micropyle. At 10 s after fertilization, several spermatozoa were detected attached to the oocyte surface. After 1 min of development, a fertilization cone that obstructed the micropyle could be observed. Segmentation started between 20 and 30 min after fertilization, when the egg cell was then formed. The first cleavage occurred between 30 and 45 min after fertilization, prior to reaching the morula stage (75 and 90 min after fertilization). The epiboly movement started at 120 and 180 min after fertilization and ended at 360 and 480 min after fertilization. Differentiation between cephalic and caudal region was detected after 420 and 600 min after fertilization and larvae hatched between 780 and 1080 min after fertilization. Seven main embryonic development stages were identified: egg cell, cleavage, morula, blastula, gastrula, segmentation with differentiation between cephalic and caudal regions, and hatching.

scholarly journals Structural and ultrastructural analysis of embryonic development ofProchilodus lineatus(Valenciennes, 1836) (Characiforme; Prochilodontidae)

Zygote ◽  
2006 ◽  
Vol 14 (3) ◽  
pp. 217-229 ◽  
Author(s):  
Alexandre Ninhaus-Silveira ◽  
Fausto Foresti ◽  
Alexandre de Azevedo
Keyword(s):  
Embryonic Development ◽  
Larval Stage ◽  
Cleavage Pattern ◽  
Optic Vesicle ◽  
Gastrula Stage ◽  
Cleavage Stage ◽  
Blastula Stage ◽  
Prochilodus Lineatus ◽  
The Third ◽  
High Mitotic Activity

SummaryThis survey was performed to characterize the embryogenesis ofProchilodus lineatus. Seven stages of embryo development were identified – zygote, cleavage, blastula, gastrula, segmentation, larval and hatching – after a period of incubation of 22 h (24 °C) or 14 h (28 °C). The following cleavage pattern was identified: the first plane was vertical (2 blastomeres); the second was vertical and perpendicular to the first (4 blastomeres); the third was vertical and parallel to the first (4 × 2); the fourth cleavage was vertical and parallel to the second (4 × 4); the fifth was vertical and parallel to the first (4 × 8); and the sixth cleavage was horizontal (64 blastomeres). At the blastula stage (3.0–4.0 h (24 °C); 1.66–2.0 h (28 °C)) irregular spaces were detected and periblast structuring was initiated. At the gastrula stage (4.0–8.0 h (24 °C); 3.0–6.0 h (28 °C)) the epiboly, convergence and cell movements, as well as the formation of embryonic layers, had begun. The segmentation stage (10.0–15.0 h (24 °C); 7.0–10.0 h (28 °C)) was characterized by a rudimentary formation of organs and systems (somites, optic vesicle and intestinal delimitation). The embryo at the larval stage (16.0–21.0 h (24 °C); 11.0–13.0 h (28 °C)) showed a free tail, more than 25 somites, an optic vesicle and a ready-to-hatch larval shape. The blastomeres at cleavage stage had disorganized nuclei indicating high mitotic activity. At gastrula, the blastomeres and the periblast had euchromatic nuclei and a large number of mitochondria and vesicles. The yolk was organized into globose sacs, which were dispersed into small pieces prior to absorption.

Structural analysis of oocytes, post-fertilization events and embryonic development of the Brazilian endangered teleost Brycon insignis (Characiformes)

Zygote ◽  
2011 ◽  
Vol 21 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Ziara A. Isaú ◽  
Elizete Rizzo ◽  
Thiciana B. Amaral ◽  
Natália M.N. Mourad ◽  
Ana T.M. Viveiros
Keyword(s):  
Electron Microscopy ◽  
Embryonic Development ◽  
Morphological Characteristics ◽  
Germinal Vesicle ◽  
Fertilization Rate ◽  
Mean Diameter ◽  
Cone Formation ◽  
The Moment ◽  
Pore Canals ◽  
Scanning Electron

SummaryThe aim of this study was to evaluate the oocytes, post-fertilization events and embryonic development in Brycon insignis, under both scanning electron microscopy and stereomicroscopy. Oocytes and embryos were sampled from spawning up to hatching. Stripped oocytes were spherical, non-adhesive, greenish-brown, possessed a single micropyle, pore-canals and had a mean diameter of 1.46 mm. In 63% of oocytes the germinal vesicle was peripheric. The main post-fertilization events were the fertilization cone formation (20 s), micropyle closure (100–180 s) and agglutination of supernumerary spermatozoa (100–180 s). Embryonic development lasted 30 h at ~24 °C and was characterized by seven stages. Zygote, cleavage, blastula and gastrula stages were first observed at 0.25, 1, 3 and 6 h post-fertilization, respectively. Fertilization rate was determined at the moment of blastopore closure, 10–11 h post-fertilization. The segmentation stage began at 11 h post-fertilization and comprised the development of somites, notochord, optic, otic and Kupffer's vesicles, neural tube, primitive intestine, and development and release of the tail. The larval stage began 21 h post-fertilization and was characterized by the presence of somites, growth and elongation of the larvae. At the hatching stage, embryos presented vigorous contractions of the tail and body leading to chorion rupture (30 h). The morphological characteristics described for B. insignis were similar to that described for other teleost species, and such knowledge is important for a better understanding of reproductive features of a species and useful for ecological and conservational studies.

Embryonic development of teleostBrycon orbignyanus

Zygote ◽  
2018 ◽  
Vol 26 (4) ◽  
pp. 294-300
Author(s):  
Luciana Nakaghi Ganeco-Kirschnik ◽  
Irene Bastos Franceschini-Vicentini ◽  
Maria do Carmo Faria Paes ◽  
Laura Satiko Okada Nakaghi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Embryonic Development ◽  
Species Conservation ◽  
Cellular Migration ◽  
Optic Vesicle ◽  
Blastula Stage ◽  
Mean Diameter ◽  
Embryonic Shield ◽  
Scanning Electron

SummaryBrycon orbignyanusis an important large teleost that is currently on the list of endangered species, therefore studies on its reproductive biology and embryology are fundamental to help species conservation and recovery. The objective of this research was to characterize the events that occur during extrusion, fertilization and embryonic development of the species. The samples were collected at predetermined times, fixed and processed for light microscopy and scanning electron microscopy. The greenish oocytes were spherical, had translucent chorion and a mean diameter of 1.3±0.11 mm. The eggs had well defined animal and vegetative poles approximately 18 min post-fertilization. Stages from 2 to 128 blastomeres occurred between 20 min and 3 h post-fertilization (hPF), when the morula was characterized. The blastula stage was observed between 2 and 3 hPF, and the gastrula between 3 and 7 hPF, when the embryonic shield emerged and the cellular migration with the consequent formation of epiblast and hypoblast. At 8 hPF, the formation of the neural tube, above the notochord and the encephalic region, was observed, delimiting the forebrain, mesencephalon and rhombencephalon regions. From 11 hPF onward, the optic vesicle was formed close to the forebrain and the embryo tail was well developed. The optic vesicle was observed from 12 hPF onward, and the tail showed an intense movement that culminated with the rupture of the chorion and consequent hatching of the larva at 13 hPF and 27°C.

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

ADHD therapy with methylphenidate in mothers – a danger for embryonic development?

2014 ◽  
Vol 47 (06) ◽  
Author(s):  
N Bergemann ◽  
K Boyle ◽  
WE Paulus
Keyword(s):  
Embryonic Development

The Influence of Ascorbic Acid on Platelet Structure and Function

1975 ◽  
Vol 34 (01) ◽  
pp. 050-062
Author(s):  
Dale H Cowan ◽  
Richard C Graham ◽  
Patricia Shook ◽  
Ronda Griffin
Keyword(s):  
Ascorbic Acid ◽  
Open Channel ◽  
Channel System ◽  
Short Intervals ◽  
Platelet Survival ◽  
Artifactual Changes ◽  
Survival Studies ◽  
And Function ◽  
Induced Aggregation ◽  
Platelet Structure

SummaryTo determine the effect on platelet behavior of transient exposure of platelets to ascorbic acid, studies of platelet function and ultrastructure were done before exposure to ascorbic acid at pH 6.5, during exposure to pH 6.5, and after restoration of pH to pre-acidifìcation levels. The effect of ascorbic acid (A. A.) was compared to that of HCl and citric acid (C. A.). ADP- and collagen-induced aggregation of normal platelets were significantly impaired by both A. A. and C. A. but were less affected by HCl. The release of 14C-serotonin was significantly reduced by each agent. The ultra-structure of normal platelets brought to pH 6.5 by A.A. was normal. After neutralization, there was marked dilatation of the open channel system and loss of the disc shape. When platelets were brought to pH 6.5 by A. A., then neutralized, the aggregates which formed after stimulation by ADP or collagen were smaller than normal, the platelets were less closely approximated, and degranulation was less complete. The data show that exposure of platelets to ascorbic acid for short intervals impairs their function when measured after restoration of pH to levels compatible with maximal responses. Platelet survival studies using autologous platelets labelled with 51Cr in the presence or absence of ascorbic acid showed that the recovery of normal platelets was unaffected by ascorbic acid, whereas recovery of platelets from patients with idiopathic thrombocytopenic purpura, idiopathic thrombocythemia, and alcohol-related thrombocytopenia was markedly reduced. The injury resulting from the use of ascorbic acid in preparing platelets for studies of platelet survival in patients with disorders affecting platelets may impair the recovery of the cells, resulting in artifactual changes in the survival studies.

Prothrombin Metz : Purification and Characterization of a Variant of Human Prothrombin

1979 ◽  
Author(s):  
M Ribieto ◽  
J Elion ◽  
D Labie ◽  
F Josso
Keyword(s):  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Factor Xa ◽  
Polyacrylamide Gel ◽  
Cleavage Pattern ◽  
Purification And Characterization ◽  
Double Immunodiffusion ◽  
The Family

For the purification of the abnormal prothrombin (Pt Metz), advantage has been taken of the existence in the family of three siblings who, being double heterozygotes for Pt Metz and a hypoprothrombinemia, have no normal Pt. Purification procedures included barium citrate adsorption and chromatography on DEAE Sephadex as for normal Pt. As opposed to some other variants (Pt Barcelona and Madrid), Pt Metz elutes as a single symetrical peak. By SDS polyacrylamide gel electrophoresis, this material is homogeneous and appears to have the same molecular weight as normal Pt. Comigration of normal and abnormal Pt in the absence of SDS, shows a double band suggesting an abnormal charge for the variant. Pt Metz exhibits an identity reaction with the control by double immunodiffusion. Upon activation by factor Xa, Pt Metz can generate amydolytic activity on Bz-Phe-Val-Arg-pNa (S2160), but only a very low clotting activity. Clear abnormalities are observed in the cleavage pattern of Pt Metz when monitored by SDS gel electrophoresis. The main feature are the accumulation of prethrombin l (Pl) and the appearance of abnormal intermediates migrating faster than Pl.

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