La localisation du matériel germinal dans le blastoderme non incube de l'oeuf de cane: étude à l'aide des irradiations aux rayons X

Development ◽  
1975 ◽  
Vol 34 (1) ◽  
pp. 171-177
Author(s):  
Par Noël Fargeix
Keyword(s):  
Germ Cells ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
X Rays ◽  
X Ray ◽  
Somite Stage ◽  
Population Decrease ◽  
Anterior Half ◽  
Duck Egg

Germinal material localization in the non-incubated duck egg blastoderm studied by means of X-ray irradiations Primordial germ cells (CGP) have been numbered from the 7-somite to the 14-somite stage in embryos formed from blastoderms the anterior or posterior halves of which have been irradiated with X-rays at the non-incubated stage or after 10 h of incubation. The germinal population decrease is almost the same for irradiations of the anterior or posterior halves at the non-incubated stage. At 10 h of incubation, this decrease is very marked for irradiations of the anterior halves while it is slight for irradiations of the posterior halves. These results seem to indicate that at the non-incubated stage, the germinal material is localized in the anterior half of the blastoderm as well as in the posterior one with a slight anterior predominance, and tends to accumulate in the anterior part only as early as the first hours of incubation.

Primordial germ cells in normal and transected duck blastoderms

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 247-260
Author(s):  
Teresa Rogulska
Keyword(s):  
Chick Embryo ◽  
Blood Vessels ◽  
Germ Cells ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
Primitive Streak ◽  
Experimental Investigations ◽  
Suggestive Evidence ◽  
Area Pellucida

Suggestive evidence for the extragonadal origin of germ cells in birds was first presented by Swift (1914), who described primordial germ cells in the chick embryo at as early a stage as the primitive streak. According to Swift, primordial germ cells are originally located extra-embryonically in the anterior part of the blastoderm and occupy a crescent-shaped region (‘germinal crescent’) on the boundary between area opaca and area pellucida. Swift also found that primordial germ cells later enter into the blood vessels, circulate together with the blood throughout the whole blastoderm and finally penetrate into the genital ridges, where they become definitive germ cells. Swift's views have been confirmed in numerous descriptive and experimental investigations. Among the latter, the publications of Willier (1937), Simon (1960) and Dubois (1964a, b, 1965a, b, 1966) merit special attention. Dubois finally proved that the genital ridges exert a strong chemotactic influence on the primordial germ cells.

The positional effect of presumptive primordial germ cells (pPGCs) on their differentiation into PGCs in Xenopus

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 527-535
Author(s):  
K. Ikenishi ◽  
Y. Tsuzaki
Keyword(s):  
Germ Cells ◽  
Germ Plasm ◽  
Germ Line ◽  
Anterior Part ◽  
Primordial Germ Cells ◽  
Positional Effect ◽  
In Series

To determine whether the location of ‘germ plasm’-bearing cells [presumptive primordial germ cells (pPGCs)] is crucial for their differentiation into PGCs in Xenopus, [3H]thymidine-labelled pPGCs were implanted into the anterior or posterior halves of the endoderm in unlabelled host neurulae. Labelled PGCs in the genital ridges of experimental tadpoles were investigated by autoradiography. When the labelled pPGCs were implanted into posterior halves of the endoderm where host pPGCs are situated, 65 and 77% of the experimental tadpoles (designated as p-tadpoles) had the labelled PGCs in series I and II, respectively. When implanted into the anterior halves, 20 and 27% of the experimental tadpoles (a- tadpoles) had the labelled PGCs in series I and II, respectively. In p-tadpoles, the average numbers of labelled PGCs per tadpole were 8á7 in series I and 10 in series II, whereas they were 2á0 in a-tadpoles of both series. Both the proportion and the average number in p-tadpoles of both series were significantly different from those in a-tadpoles. In both series, labelled PGCs in p-tadpoles were found to be distributed throughout the genital ridges while those in a-tadpoles were localized only in the anterior part of the ridges. These facts indicate that the location of pPGCs in the endoderm affects their successful migration into the genital ridges, and that not only the presence of the germ plasm but also the proper location in endoderm are prerequisites to PGC differentiation of the germ line cells.

The synthetic activity of primordial germ cells in normal and irradiated neonatal male rats

Development ◽  
1968 ◽  
Vol 19 (2) ◽  
pp. 239-249
Author(s):  
I. C. Lett
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Giant Cells ◽  
Male Rats ◽  
Synthetic Activity ◽  
X Rays ◽  
Short Term ◽  
Post Irradiation ◽  
Histological Appearance ◽  
Transitional Cells

Resting primordial germ cells or gonocytes, present in the testis of the rat at birth (Beaumont & Mandl, 1963), are highly radiosensitive. A dose of 50–100 r X-rays induces complete, or almost complete, sterility, as judged by the histological appearance of the testis at 25 days post parturn (Mandl et al. 1964). Studies of short-term post-irradiation changes have revealed that gonocytes, exposed to a sterilizing dose of X-rays at birth, do not degenerate immediately after exposure but differentiate normally into transitional cells (the immediate precursors of definitive germ cells; Beaumont & Mandl, 1963; Huckins, 1963; Franchi & Mandl, 1964) so that no histological abnormalities are detectable for 5 or 6 days. Subsequently, however, the irradiated transitional cells fail to divide; they increase markedly in size and form irregularly shaped giant cells which eventually become pyknotic (Franchi & Mandl, 1966; see also Sapsford, 1965a).

Selective decrease of chick embryonic primordial germ cells in vivo and in vitro by soft X-ray irradiation

2006 ◽  
Vol 95 (1-2) ◽  
pp. 67-74 ◽  
Author(s):  
Jeong M. Lim ◽  
Huck M. Kwon ◽  
Duk K. Kim ◽  
Jin N. Kim ◽  
Tae S. Park ◽  
...  
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
X Ray

Effect of soft X-ray irradiation on the migratory ability of primordial germ cells in chickens

2007 ◽  
Vol 48 (2) ◽  
pp. 121-126 ◽  
Author(s):  
M. Naito ◽  
T. Harumi ◽  
T. Minematsu ◽  
A. Tajima ◽  
T. Kuwana
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
X Ray

Combined action of X-rays and nonylphenol on mouse sperm

2011 ◽  
Vol 6 (3) ◽  
pp. 320-329 ◽  
Author(s):  
Małgorzata Dobrzyńska
Keyword(s):  
Dna Damage ◽  
Germ Cells ◽  
Sperm Morphology ◽  
Sperm Count ◽  
X Rays ◽  
Combined Exposure ◽  
X Ray ◽  
Combined Action ◽  
Sperm Count And Morphology ◽  
Higher Doses

AbstractThe aim of this study was to assess the effects of 2-weeks’ X-ray and/or nonylphenol (NP) exposure on male mice’s sperm count and quality. Pzh:SFIS mice were exposed to X-rays (0.05 Gy, 0.10 Gy, 0.20 Gy) or to nonylphenol (25 mg/kg bw, 50 mg/kg bw, 100 mg/kg bw) or to both agents (0.05 Gy + 25 mg/kg bw NP, 0.10 Gy + 50 mg/kg bw NP). At 24 h and 5 weeks after the end of exposure the sperm count, morphology and frequency of DNA damage in the male germ cells were estimated. Each agent alone diminished sperm count and morphology. The dose of 0.05 Gy of X-rays decreased the frequency of DNA damage. Combined exposure to lower doses of both agents significantly improved sperm morphology and decreased the level of DNA damage compared to one agent alone. Combined exposure to higher doses reduced the frequency of DNA damage compared to the effect of the appropriate dose of NP. Results of combined exposure to low doses of both agents suggest that 0.05 Gy of X-rays stimulate the DNA damagecontrol system and in consequence repair of DNA caused by X-rays and NP. It may be correlated with increased antioxidant capacity.

Location of pre-hepatic cells in the early developmental stages of quail embryos

Development ◽  
1981 ◽  
Vol 64 (1) ◽  
pp. 73-85
Author(s):  
Sumiko Fukuda-Taira
Keyword(s):  
Developmental Stages ◽  
Anterior Part ◽  
Primitive Streak ◽  
Lower Half ◽  
Somite Stage ◽  
Hepatic Cells ◽  
Anterior Half ◽  
Early Developmental Stages ◽  
Early Developmental ◽  
Cardiac Mesoderm

The location of the pre-hepatic cells which can respond to the inductive influence of the cardiac mesoderm and differentiate to the hepatic epithelium was investigated in quail embryos between the unincubated and 8-somite stages. These cells were found to exist in the whole area of the blastoderm of unincubated and prestreak stages. At the short-streak stage, just before the beginning of gastrulation, pre-hepatic cells are confined to the anterior part of the primitive streak. During gastrulation, prehepatic cells invaginate through this area of the primitive streak and enter the endoblastic layer. They are found in the anterior half of the endoblastic layer as well as in the lower half of the anterior part of the primitive streak at the medium- to definitive-streak stages. After gastrulation, they are consistently found only in the anterior half of the endoblastic layer. From the 1-somite stage, at least up to the 8-somite stage, the pre-hepatic cells are localized in the endoderm, anterior to the level of the 3rd somite. Since the pre-hepatic cells or their progenitors were always found within the definitive endoblast which invaginates from the epiblast during gastrulation, it can be presumed that the pre-hepatic cells originate from the epiblast, invaginate through the anterior part of the primitive streak between the short- and the definitive-streak stage, and enter the definitive endoblast.

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