Special Problems of Experimenting in ovo on the Early Chick Embryo, and a Solution

Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 369-375
Author(s):  
P. H. S. Silver

It seems to be generally accepted that experimenting in ovo on the chick during the early stages of development (up to about 48 hours) is fraught with the greatest difficulty. After about this time no serious technical problems arise and a high proportion of successful results can be expected. It is natural to ask why there should be this change-over from extreme difficulty to reasonable simplicity. New (1955) attributed to this ‘inaccessibility of the chick embryo in the egg’ the invention of his own and many other in vitro methods during the last 30 years. There is no doubt that, when short-term experiments only are required, in vitro methods will probably always be preferred. But all in vitro methods suffer from the disadvantage that the embryo cannot be expected to survive for more than 48 hours or so after explantation.

1991 ◽  
Vol 99 (2) ◽  
pp. 431-441
Author(s):  
A.J. Brown ◽  
E.J. Sanders

In the gastrulating chick embryo, the mesoderm cells arise from the epiblast layer by ingression through the linear accumulation of cells called the primitive streak. The mesoderm cells emerge from the streak with a fibroblastic morphology and proceed to move away from the mid-line of the embryo using, as a substratum, the basement membrane of the overlying epiblast and the extracellular matrix. We have investigated the roles of fibronectin and laminin as putative substrata for mesoderm cells using complementary in vivo and in vitro methods. We have microinjected agents into the tissue space adjacent to the primitive streak of living embryos and, after further incubation, we have examined the embryos for perturbation of the mesoderm tissue. These agents were: cell-binding regions from fibronectin (RGDS) and laminin (YIGSR), antibodies to these glycoproteins, and a Fab' fragment of the antibody to fibronectin. We find that RGDS, antibody to fibronectin, and the Fab' fragment cause a decrease in the number of mesoderm cells spread on the basement membrane, and a perturbation of cell shape suggesting locomotory impairment. No such influence was seen with YIGSR or antibodies to laminin. These results were extended using in vitro methods in which mesoderm cells were cultured in fibronectin-free medium on fibronectin or laminin in the presence of various agents. These agents were: RGDS; YIGSR; antibodies to fibronectin, fibronectin receptor, laminin and vitronectin; and a Fab' fragment of the fibronectin antiserum. We find that cell attachment and spreading on fibronectin is impaired by RGDS, antiserum to fibronectin, the Fab' fragment of fibronectin antiserum, and antiserum to fibronectin receptor. The results suggest that although the RGDS site in fibronectin is important, it is probably not the only fibronectin cell-binding site involved in mediating the behaviour of the mesoderm cells. Cells growing on laminin were perturbed by YIGSR, RGDS and antibodies to laminin, suggesting that mesoderm cells are able to recognise at least two sites in the laminin molecule. We conclude that the in vivo dependence of mesoderm cells on fibronectin is confirmed, but that although these cells have the ability to recognise sites in laminin as mediators of attachment and spreading, the in vivo role of this molecule in mesoderm morphogenesis is not yet certain.


Nature ◽  
1976 ◽  
Vol 263 (5578) ◽  
pp. 588-591 ◽  
Author(s):  
A. K. DESHPANDE ◽  
M. A. Q. SIDDIQUI

2015 ◽  
Vol 27 (1) ◽  
pp. 116
Author(s):  
K. L. Beck ◽  
J. Singh ◽  
M. Anzar

Successful cryopreservation of bovine ovarian tissue holds enormous potential for long-term maintenance of female gametes to preserve genetic diversity by tissue banking. Traditionally, in vitro culture followed by histopathological examination has been used to assess the post-thaw viability of cryopreserved tissues. Recently, in ovo transplantation of mammalian tissues on the chorio-allantoic membrane (CAM) of a growing chicken embryo has emerged as an alternative method for short-term culture. The purpose of this experiment was to compare CAM culture of bovine ovarian tissue over a 5-day period with the in vitro culture system. Fertilized White Leghorn eggs were incubated at 37°C and 62% relative humidity. A window (1 × 2 cm) was cut into the eggshell on Day 3 of incubation. Ovaries were retrieved from a local abattoir and brought to the laboratory within 6 h. Ovarian cortex pieces (1–2 mm3) were randomly assigned to control, CAM-culture, or in vitro-culture groups. Control-group tissues were fixed immediately in 4% paraformaldehyde. The CAM was traumatized on Day 10 of incubation to expose the underlying blood vessels, and tissue pieces were grafted at the site (one graft per egg). For in vitro culture, the ovarian cortex pieces were placed on tissue culture inserts within 6-well plates containing TCM199 with 1% insulin-transferrin-selenium, 100 mIU mL–1 of FSH, 100 IU mL–1 of penicillin, and 50 μg mL–1 of streptomycin and incubated at 38°C in 5% CO2. Ovarian tissues from the CAM and in vitro culture group were removed on Day 1, 3, and 5 of grafting/culture, fixed, embedded in paraffin, sectioned at 5 μm, stained with hematoxylin-eosin, and analysed under a light microscope. The numbers of normal and degenerated follicles (indicating follicle survival) and number of blood vessels containing bovine and avian red blood cells (indicating angiogenesis) were counted using standard stereological procedures. All ovarian cortex grafts from surviving chick embryos showed adhesion with the CAM and a marked neo-vascularization in the graft areas. Gross and histological examination revealed the circulation of avian blood cells in ovarian stromal vessels with a concomitant decrease in the number of bovine blood vessels over the incubation period. Total follicle densities (mean ± s.e.m.) on Day 1, 3, and 5 were 13.3 ± 5.9, 27.9 ± 6.7, and 36.9 ± 7.3 in the in vitro-cultured group and 36.7 ± 13.0, 73.6 ± 24.0, and 44.02 ± 12.67 per millimeter cubed in the CAM-cultured group, respectively. Overall, total follicle density was higher in the CAM-cultured group (P < 0.05). Likewise, the normal follicle densities on Day 1, 3, and 5 were 10.4 ± 4.9, 15.5 ± 3.6, and 20.7 ± 6.3 in the in vitro-cultured group and 30.5 ± 8.5, 45.7 ± 18.4, and 22.7 ± 7.3 per millimeter cubed in the CAM-cultured group (P > 0.05). In conclusion, in ovo CAM grafting system was as successful as the in vitro-culture system and may be considered an acceptable alternative to the traditional in vitro-culture system for bovine ovarian tissue.


Development ◽  
1983 ◽  
Vol 77 (1) ◽  
pp. 153-165
Author(s):  
L. Fucci ◽  
C. Cirotto ◽  
L. Tomei ◽  
G. Geraci

The synthesis of globins in the chick embryo before the onset of circulation has been studied in situ by specific immunofluorescence labelling of embryonic sections and by labelling newly synthesized proteins in ovo and in vitro in embryonic explants with [3H]leucine. The presence of major primitive haemoglobins is observed by 28 h of incubation. The minor primitive haemoglobins become detectable by immunofluorescence after 40 h of development, shortly before the onset of circulation. 3H-labelling shows that one definitive α chain is synthesized, though in low concentration, from the initial globin detection. The other definitive α chain is observed in embryos of at least 40 h of development. The relative concentration of the two definitive α chains changes rapidly with development indicating a specific mechanism of regulation. An erythropoietic site is observed in the wall of the dorsal aorta in embryos of about 45–50 h of development. From the initial detection, those cells contain all four primitive embryonic haemoglobins, in contrast to what is observed for the cells of the blood islands.


Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 175-190
Author(s):  
K. Palén ◽  
L. Thörneby

Chick embryos were treated in ovo and in vitro with L-phenylalanine from the intermediate streak stage (Hamburger & Hamilton stage 3, 12–13 h of incubation) to the 7-somite stage (H & H stage 9, 29–33 h of incubation). Treatment in ovo resulted in a large number of embryos developing somite blocks, i.e. imperfectly segmented somites. In embryos treated at an early developmental stage (12–21 h of incubation), the blocks of unsegmented somite mesoderm occurred mostly in the somite pairs 1–5, whereas treatment that began at a later stage (24–30 h of incubation) caused blocks in the somite pairs 5–10, i.e. the appearance of blocks of unsegmented somite mesoderm is correlated in time with the onset of the treatment. No difference regarding mitotic indices could be distinguished between normally segmented somites and blocks of unsegmented somite mesoderm. Autoradiography based on tritiated L-phenylalanine showed no regional differences in labelling of the chick embryo body. Electronmicroscopical observations indicate a slightly suppressed formation of microvilli in the cells of the unsegmented mesoderm blocks compared with cells in normally segmented somites. The observed disturbances are probably caused by a suppressed yolk granule decomposition in the developing somite cells. The experiments in vitro support the findings in the in ovo material; at the same time, they reveal an unexpectedly slow diffusion of L-phenylalanine through the vitelline membrane.


In Vitro ◽  
1973 ◽  
Vol 8 (5) ◽  
pp. 383-385 ◽  
Author(s):  
Robert C. Fitzsimmons ◽  
Donna E. Mason

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