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.

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 Embryonic development in Zungaro jahu

Zygote ◽  
2016 ◽  
Vol 25 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Camila Marques ◽  
Francine Faustino ◽  
Bruno Bertolucci ◽  
Maria do Carmo Faria Paes ◽  
Regiane Cristina da Silva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Embryonic Development ◽  
Egg Cell ◽  
Gastrula Stage ◽  
Transmission Electron ◽  
Larval Hatching ◽  
Morula Stage ◽  
Zygote Stage ◽  
Scanning Electron

SummaryThe aim of this study was to characterize the embryonic development of Zungaro jahu, a fresh water teleostei commonly known as ‘jaú’. Samples were collected at pre-determined times from oocyte release to larval hatching and analysed under light microscopy, transmission electron microscopy and scanning electron microscopy. At the first collection times, the oocytes and eggs were spherical and yellowish, with an evident micropyle. Embryo development took place at 29.4 ± 1.5°C and was divided into seven stages: zygote, cleavage, morula, blastula, gastrula, organogenesis, and hatching. The differentiation of the animal and vegetative poles occured during the zygote stage, at 10 min post-fertilization (mpf), leading to the development of the egg cell at 15 mpf. From 20 to 75 mpf, successive cleavages resulted in the formation of 2, 4, 8, 16, 32 and 64 blastomeres. The morula stage was observed between 90 and 105 mpf, and the blastula and gastrula stage at 120 and 180 mpf; respectively. The end of the gastrula stage was characterized by the presence of the yolk plug at 360 mpf. Organogenesis followed, with differentiation of the cephalic and caudal regions, elongation of the embryo by the cephalo-caudal axis, and somitogenesis. Hatching occurred at 780 mpf, with mean larval total length of 3.79 ± 0.11 mm.

Antitumoral drug loaded in TEOS nanoparticles

2012 ◽  
Vol 1498 ◽  
pp. 9-14 ◽  
Author(s):  
Ana Paula V. Araújo ◽  
Claure N. Lunardi ◽  
Anderson J. Gomes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Slow Release ◽  
Sol Gel ◽  
Aqueous Media ◽  
Tetraethyl Orthosilicate ◽  
Mean Diameter ◽  
Immunomodulating Drug ◽  
Distribution Studies ◽  
Scanning Electron

ABSTRACTMethotrexate (MTX), is a potent immunomodulating drug and widely used in the treatment of cancer, psoriasis and others disease. Despite its efficacy, the use of MTX is greatly limited due to its toxicity. To solve this problem, we prepared nanoparticles of tetraethyl orthosilicate (NP-TEOS) containing the compound methotrexate (MTX), by the sol-gel method. This drug delivery system (DDS) showed a loading efficiency of 39.7%. Size distribution studies were performed with dynamic light scattering and scanning electron microscopy revealing that these particles were spherical in shape, with a mean diameter between 140-430 nm and a low polydispersity (0.12 – 0.26). Also the particles displayed a low tendency toward aggregation which was confirmed by the low zeta potential -61.4 mV. Profile release showed a slow release loaded with MTX (PBS buffer pH = 7.4). The slow release can be attributed to the low porosity of the NP-TEOS and the extremely low diffusivity of MTX in aqueous media. B16-F10 cells were used to assay the toxicity and uptake of NP-TEOS showing to be nontoxic without MTX making a good candidate for DDS.

scholarly journals Structural analysis of fertilization in the fish Brycon orbignyanus

Zygote ◽  
2009 ◽  
Vol 17 (2) ◽  
pp. 93-99 ◽  
Author(s):  
Luciana Nakaghi Ganeco ◽  
Irene Bastos Franceschini-Vicentini ◽  
Laura Satiko Okada Nakaghi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Animal Pole ◽  
Species Survival ◽  
Mean Diameter ◽  
Vegetal Pole ◽  
The Moment ◽  
Egg Diameter ◽  
Consequent Increase ◽  
Scanning Electron

SummaryIn the present work, we analyzed the structure of oocytes and fertilized eggs of the piracanjuba fish (Brycon orbignyanus) under light and scanning electron microscopy. After inducing spawning, samples were collected at the moment of oocyte extrusion, when oocytes and semen were mixed (time 0), as well as at 10, 20 and 30 s after mixing, every minute up to 10 min, and then at 15 and 20 min. The oocytes are spherical, translucent and greenish with a mean diameter of 1.3 ± 0.11 mm. During the extrusion, cytoplasmic movement was observed in eggs towards the micropyle, characterizing the animal pole. At the moment of fertilization, the cortical cytoplasm showed a higher concentration of cortical alveoli at the animal pole than at the vegetal pole. The cortical alveoli breakdown promoted the elevation of the chorion with a consequent increase in egg diameter (1.95 ± 0.08 mm). The penetration of the spermatozoon promotes the formation of a fertilization cone of spherical external structure, which obstructs the opening of the micropyle. This structure acts as a main mechanism to avoid polyspermy, intercepting the access of supernumerary spermatozoa. Such studies about the reproductive biology of fish are important to species survival and conservation programmes.

Effect of electrospinning parameters on production of polyvinyl alcohol/polylactic acid nanofiber using a mutual solvent

2021 ◽  
pp. 096739112110271
Author(s):  
Reyhaneh Fatahian ◽  
Mohammad Mirjalili ◽  
Ramin Khajavi ◽  
Mohammad Karim Rahimi ◽  
Navid Nasirizadeh
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Water Absorption ◽  
Average Diameter ◽  
Poly Lactic Acid ◽  
Poly Vinyl Alcohol ◽  
Mean Diameter ◽  
Scanning Electron

Differences in the properties of poly(vinyl alcohol) (PVA) and poly (lactic acid) (PLA) polymers have attracted much attention today. In this research, the aim is to produce PVA/PLA nanofibers with hydrophilicity and good mechanical properties using a mutual solvent. In this regard, the ability to produce PVA/PLA nanofibers using a mutual solvent was evaluated. The effect of electrospinning parameters on the morphology of nanofibers, hydrophilicity of nanofibers produced by measuring water absorption and contact angle as well as mechanical properties of nanofibers were considered. The results obtained from scanning electron microscopy analyses of the structure of these fibers showed that PVA had the highest viscosity of 5.64 Pa.s and the highest diameter of 260 nm, which decreased the thickness of the nanofibers with increasing PLA. And pure PLA had the lowest mean diameter of 76 nm. In the consideration of the mechanical properties of the prepared nanofibers, it was found that the combination of PLA and PVA nanofibers will lead to overlap the properties of each other and the creation of desirable mechanical properties. Moreover, in the investigation of water absorption and contact angle, it was concluded that the PVA/PLA was fully absorbed in less than 200 seconds and the samples have a contact angle of less than 52°. Finally, it was found that the average diameter of the produced nanofibers was decreased by increasing the voltage and the needle tip to collector distance by considering the PVA/PLA samples with a ratio of 50:50.

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