Analysis of an Hertwig effect in the rainbow trout (Salmo gairdneri Richardson) after fertilization with gamma-irradiated sperm.
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Biomedical subjects
D Chourrout
Publications and source records attributed to D Chourrout.
Thermal induction of diploid gynogenesis and triploidy in the eggs of the rainbow trout (Salmo gairdneri Richardson).
Sporadic diploid gynogenetic fry resulted from fertilization with gamma-irradiated sperm. Their frequency increased appreciably when thermal shock treatments, beginning during the first hour of development (--0.4 degrees C lasting 6 hrs 45 min; 26-30 degrees C lasting 10 min), were used. When the eggs were fertilized with normal sperm, a good triploidization rate was induced by means of heat shocks (27-30 degrees C lasting 10 min). It is supposed that the retention of the second polar body caused the gynogenetic diploidy observed.
Animals↗
Production of YY rainbow trout males by self-fertilization of induced hermaphrodites.
Dietary administration of various estrogens for three months from swim-up stage resulted in excess of females, the remainder of the treated groups consisting of males and hermaphrodites. Mature hermaphrodites were self-fertilized or mated with standard males and females. These hermaphrodites and some of the estrogen-treated females proved to be genetic males; the frequencies of males obtained from their ova averaged 76.6%, suggesting viability of the YY genotype. Four of nine tested males of those progenies provided all male offspring when mated with standard females.
Animals↗
No transgenic rainbow trout produced with sperm incubated with linear DNA.
We attempted to produce transgenic rainbow trout embryos by fertilizing eggs with sperm incubated with linearized plasmids. One experiment was conducted with the construct pBGH7 in the medium MMSF, with or without DMSO, at 2 concentrations of sperm cells and a relatively low concentration of DNA. The DNA was also in contact with the eggs during insemination and during the first minutes of egg activation. The second experiment was conducted with the construct CMVCAT in the medium MMSF, at 2 concentrations of sperm cells and a much higher concentration of DNA. The DNA was also present during the insemination. DNA analyses and dosages of CAT activity did not permit detection of any transgenic fry. However, one result suggests that sperm cells can capture part of the linear DNA in teh conditions tested.
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