An ultrastructural study of embryo and endosperm development during in vitro culture of maize ovaries (Zea mays)

1986 ◽  
Vol 64 (10) ◽  
pp. 2227-2238 ◽  
Author(s):  
J. H. N. Schel ◽  
H. Kieft

A culture method is described which allows the continuous supply of fresh liquid medium and which prevents the accumulation of toxic metabolites. Development of maize embryos and endosperm after various periods of in vitro ovary culture was studied by light and electron microscopy. Using this method the ultrastructural features of embryo development in vitro were similar to those of in vivo embryos. In contrast, the formation of endosperm was irregular with the absence of cellularization of the inner endosperm being frequent. In some cases, only the endosperm developed without any indication of embryo formation. In a calcium-depleted medium, embryo development was normal but again, endosperm formation was aberrant. No cells were formed in the central part of the endosperm and near the placental region degeneration took place, resulting in vacuoles with dark inclusions, clumps of rough endoplasmic reticulum membranes, and cellular breakdown. The events occurring after in vitro culture strongly resemble those taking place after intergeneric crosses or crosses between diploid and tetraploid strains. It is concluded that defective endosperm development is probably the main factor for the failure of embryo development.

2011 ◽  
Vol 23 (1) ◽  
pp. 124
Author(s):  
C. Feltrin ◽  
M. Machado ◽  
L. M. V. Queiroz ◽  
M. A. S. Peixer ◽  
P. F. Malard ◽  
...  

In vitro embryo production by handmade cloning (HMC) usually requires individual embryo culture, because zona-free embryos cannot be grouped in standard in vitro culture (IVC) protocols. The aim of this study was to evaluate the developmental potential of bovine embryos produced by HMC (Ribeiro et al. 2009 Cloning Stem Cells 11, 377–386) after in vitro culture (IVC) in 3 microwell (WOW) systems. After in vitro maturation, oocytes were denuded and incubated in demecolcine (Ibáñez et al. 2003 Biol. Reprod. 68, 1249–1258), followed by zona pellucida removal, oocyte bisection, embryo reconstruction, electrofusion, and chemical activation. Cloned embryos were allocated to 1 of 3 IVC groups: cWOW: conventional microwells (250 μm, round; Vajta et al. 2000 Mol. Reprod. Dev. 55, 256–264); mWOW: modified microwells (130 μm, conical; Feltrin et al. 2006 Reprod. Fert. Dev. 18, 126); and WOW-PDMS: microwells in polydimethylsiloxane chips (170 μm, cylindrical with microchannels); IVF embryos were used as controls (Bertolini et al. 2004 Reproduction 128, 341–354). Cleavage (Day 2), blastocyst (Day 7), and pregnancy (Day 30) rates were analysed by the chi-square test, for P < 0.05. Results are shown in Table 1. Cleavage rates were similar between groups, but development to the blastocyst stage was higher in IVF controls than cloned embryo groups. Among cloned embryo groups, blastocyst rate was higher in the mWOW group than the conventional and the PMDS-based microchannels. Nevertheless, in vivo development to Day 30 of pregnancy was not different between cloned groups. Our results for in vitro embryo development indicated that the mWOW provided more suitable conditions for embryo development to the blastocyst stage when compared with cWOW or even WOW-PDMS. Among some possible reasons include the physical advantage of a smaller microwell that may better mimic the constraining effect of the zona pellucida on the developing embryo. That may also provide greater blastomere stability, favouring the aggregation state during the first rounds of cleavages, also aiding compaction and subsequent cavitation. The narrower microwell system appeared to have promoted better in vitro development than the conventional and the DMPS-based microwell systems, with no impact on subsequent in vivo development. However, the IVC in the WOW-PDMS system supported reasonable rates of development, in accordance with the current literature. Table 1.In vitro development of bovine IVF and cloned embryos produced after the in vitro culture in distinct IVC systems


Reproduction ◽  
1994 ◽  
Vol 100 (1) ◽  
pp. 131-136 ◽  
Author(s):  
L. A. Johnston ◽  
J. J. Parrish ◽  
R. Monson ◽  
L. Leibfried-Rutledge ◽  
J. L. Susko-Parrish ◽  
...  

1998 ◽  
Vol 49 (1) ◽  
pp. 173 ◽  
Author(s):  
M. O'Kearney-Flynn ◽  
M. Wade ◽  
P. Duffy ◽  
V. Gath ◽  
M.P. Boland ◽  
...  

2014 ◽  
Vol 26 (1) ◽  
pp. 128
Author(s):  
C. P. Buemo ◽  
A. Gambini ◽  
I. Hiriart ◽  
D. Salamone

Somatic cell nuclear transfer (SCNT) derived blastocysts have lower cell number than IVF-derived blastocysts and their in vivo counterparts. The aim of this study was to improve the blastocyst rates and quality of SCNT blastocysts by the aggregation of genetically identical free zona pellucida (ZP) porcine clones. Cumulus–oocyte complexes were recovered from slaughterhouse ovaries by follicular aspiration. Maturation was performed in TCM for 42 to 48 h at 39°C and 5% CO2. After denudation by treatment with hyaluronidase, mature oocytes were stripped of the ZP using a protease and then enucleated by micromanipulation; staining was performed with Hoechst 33342 to observe metaphase II. Ooplasms were placed in phytohemagglutinin to permit different membranes to adhere between each other; the ooplasm membrane was adhered to a porcine fetal fibroblast from an in vitro culture. Adhered membranes of the donor cell nucleus and enucleated oocyte cytoplasm were electrofused through the use of an electric pulse (80 V for 30 μs). All reconstituted embryos (RE) were electrically activated using an electroporator in activation medium (0.3 M mannitol, 1.0 mM CaCl2, 0.1 mM MgCl2, and 0.01% PVA) by a DC pulse of 1.2 kV cm–1 for 80 μs. Then, the oocytes were incubated in 2 mM 6-DMAP for 3 h. In vitro culture of free ZP embryos was achieved in a system of well of wells in 100 μL of medium, placing 3 activated oocytes per microwell (aggregation embryo), whereas the control group was cultivated with equal drops without microwells. Embryos were cultivated at 39°C in 5% O2, 5% CO2 for 7 days in SOF medium with a supplement of 10% fetal bovine serum on the fifth day. The RE were placed in microwells. Two experimental groups were used, control group (not added 1X) and 3 RE per microwell (3X). At Day 7, resulting blastocysts were classified according to their morphology and diameter to determine their quality and evaluate if the embryo aggregation improves it. Results demonstrated that aggregation improves in vitro embryo development rates until blastocyst stage and indicated that blastocysts rates calculated over total number of oocytes do not differ between groups (Table 1). Embryo aggregation improves cleavage per oocyte and cleavage per microwell rates, presenting statistical significant differences and increasing the probabilities of higher embryo development generation until the blastocyst stage with better quality and higher diameter. Table 1.Somatic cell nuclear transfer cloning and embryo aggregation


Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 798-801 ◽  
Author(s):  
Laura K. Thompson ◽  
Gerald R. Leather ◽  
Maynard G. Hale

The culture of ovules excised from velvetleaf (Abutilon theophrasti Medic., ♯4 ABUTH) capsules 5 days after anthesis was used to measure the effects of abscisic acid (ABA) and sucrose on embryo development and prevention of precocious germination. ABA at 1 × 10-7 M combined with 6% sucrose in the medium for the first 14 days of culture increased embryo development but prevented precocious germination. Higher concentrations of ABA inhibited embryo development. Without ABA, precocious germination increased directly with the concentration of sucrose in the medium, and embryos died. In vivo, ABA reached its highest concentration in ovules 5 days after anthesis but was undetectable after 16 days. Parental control of embryo development may involve ABA and an increasing concentration of osmoticum as seeds dehydrate during maturation.


2013 ◽  
Vol 25 (1) ◽  
pp. 165
Author(s):  
A. Gambini ◽  
J. Jarazo ◽  
A. De Stefano ◽  
F. Karlaninan ◽  
D. Salamone

Somatic donor cells play a major role during the NT procedure. In vitro culture conditions may affect the capability of these cells to be reprogrammed and to allow embryo development. The aim of this study was to evaluate the effect of in vitro culture at low (5%) or atmospheric (20%) oxygen tension in somatic donor cells for cloned equine embryo production. Adult fibroblasts were obtained through culture of minced tissue from neck biopsies of one horse skin. They were cultured in DMEM supplemented with 10% fetal bovine serum (FBS) and 1% antibiotics in 2 groups: (1) 5% CO2 and (2) 5% CO2 and 5% O2, both groups in humidified air at 39°C. Quiescence of donor cells was induced by growth to confluency for 3 to 5 days prior to NT. Oocyte collection, maturation, cloning, and activation procedures were performed as described by Gambini et al. (2012 Biol. Reprod. 87, 1–9.). After activation, reconstructed embryos (RE) were cultured in DMEM/F12 supplemented with 5% FBS in the well of the well system as 3 reconstructed embryos per well. Cleavage and blastocyst formation (7–8 days) of the experimental groups were assessed. In vitro development, on a per-well and RE basis, was compared using the chi-square test. No statistical differences were observed in cleavage [(1): 48/84, 57%; (2): 54/87, 62%). No difference was observed in blastocyst rates on a per-well basis [(1): 5/28, 18%; (2): 4/29, 14%] or on a per-RE basis [(1): 5/84, 6%; (2): 4/87, 5%]. This work suggests that the oxygen tension during the in vitro culture of somatic donor cells does not affect the quantity of the cloned equine blastocyst produced. Further studies are required to determine if these conditions would affect in vivo embryo development.


Plant Science ◽  
2006 ◽  
Vol 170 (6) ◽  
pp. 1052-1058 ◽  
Author(s):  
Karine Gallardo ◽  
Caroline Kurt ◽  
Richard Thompson ◽  
Sergio Ochatt

1990 ◽  
Vol 43 (5) ◽  
pp. 733-744 ◽  
Author(s):  
A. M. Donoghue ◽  
L. A. Johnston ◽  
U. S. Seal ◽  
D. L. Armstrong ◽  
R L. Tilson ◽  
...  

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