Alain Chevallier

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Quail-to-chick grafting experiments performed during the third day of incubation demonstrate that somites can contribute to limb development. In orthotopic recombinations, migrating cells originating from the grafted unsegmented or segmented somitic mesoderm adjacent to the wing or leg field end up in the musculature respectively of the wing or the leg,(More)
In chick embryos, observations were made on serial semithin transverse sections of the wing level. In addition homo- or heterotopic replacements of the wing or leg somitic mesoderm by labelled somitic or nonsomitic mesoderm were made in 2-to 2.5-day embryos. The nuclear label used was either natural (quail donor embryos in heterotopic transplantations) or(More)
The aim of this study performed in the embryonic chick wing is to test the ability of the tendons to form and develop in the absence of the muscle bellies. The experiments were performed on 2-day chick embryos by destroying a portion of the somitic mesoderm by local X-irradiation. The irradiated part included the wing somite level 15-20 and extended three(More)
By modifying the temporal relationship between connective tissue and myogenic cell invasion during early limb bud development new evidence of the organizing role of the connective tissue was obtained. Muscle cell-deprived wing buds were allowed to grow up to stages 22 to 27 of Hamburger and Hamilton, when they received a transplant of quail myogenic cells(More)
The regional embryonic origin of trunk and limb musculature was determined through heterospecific homotopic or heterotopic transplantations of quail somitic or somiticsomatopleural mesoderm into chick hosts, and through localized X-irradiation of the somitic mesoderm. Experiments were performed on 2-day embryos. Results show that the myoblastic component of(More)
If the somitic mesoderm of a 2-day chick embryo is destroyed by X-irradiation, the adjacent limb develops with a normal pattern of connective tissues, but is devoid of muscle. The innervation of muscleless wings produced in this way was examined in silver-stained whole mounts, fixed 3 to 8 days later. The main nerve trunks and their cutaneous branches(More)
The rapid development of the silk glands of Bombyx mori during the last larval instar shows two phases. During the first 4 days, in both the middle and posterior parts of the silk glands, the ribosomal machinery is assembled and the synthesis of housekeeping proteins starts. During the second phase (the last 4 days), the middle part of the gland synthesis(More)
Since 1977, CHEVALLIER et al. had the idea that, although limb muscle cells are usually of somitic origin, somatopleural cells could give rise to myocytes under certain experimental conditions. New experiments were undertaken in order to investigate further the differentiating capacities of the limb somatopleural mesoderm. Two-day quail limb somatopleural(More)
The aim of this study is to test the ability of the intrinsic wing musculature to develop in the absence of somitic mesoderm. The experiments were performed on 2- to 2.5-day chick embryos either by replacing the somitic mesoderm adjacent to the wing field with a piece of 9-day chick embryonic midgut or by destroying, through local X-irradiation, not only(More)