ABSTRACT
The effect of laser optical perforation of the zona pellucida on the viability and development of mouse embryos has been studied. Operations of zona pellucida thinning and single or double perforation were carried out on 2-cell embryo, morula, and blastocyst stages with a laser pulse (wavelength 1.48 µm, pulse duration 2 ms). Embryo development up to the blastocyst stage and hatching efficiency were statistically analyzed. It was found that 2-cell or morula stage embryo zona pellucida thinning or single perforation did not affect development to the blastocyst stage and number of hatched embryos, but it accelerated embryo hatching compared to control groups one day earlier in vitro. Double optoperforation on 2-cell embryo or morula stage did not significantly affect development to the blastocyst stage, but it strongly decreased the number of hatched embryos. Also, zona pellucida perforation at the blastocyst stage had a negative effect: hatching did not occur after this manipulation. Blastocyst cell number calculation after single zona pellucida perforation at 2-cell and morula stages showed that cell number of hatching or hatched blastocysts did not differ from the same control groups. This fact points out that the laser single optoperforation method is a useful and safe experimental tool that allows further manipulations within the zona pellucida.
Subject(s)
Embryonic Development/physiology , Zona Pellucida/physiology , Animals , Blastocyst/physiology , Blastocyst/radiation effects , Blastomeres/physiology , Blastomeres/radiation effects , Embryonic Development/radiation effects , Female , Lasers , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Photobiology/methods , Pregnancy , Zona Pellucida/radiation effectsSubject(s)
Lasers , Nuclear Transfer Techniques/instrumentation , Animals , Cell Nucleolus/radiation effects , Embryonic Development/radiation effects , Female , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Oocytes/cytology , Oocytes/radiation effects , Zygote/cytology , Zygote/radiation effectsSubject(s)
Cloning, Organism/methods , Lasers , Micromanipulation/methods , Animals , Female , Mice , Mice, Inbred C57BL , PregnancyABSTRACT
The injection of purified Rous sarcoma virus (RSV) (Prague strain) into Drosophila melanogaster (Oregon R line) eggs changes the fly phenotype in certain cases, and RSV-specific sequences can be identified in the Drosophila genome (ref. 1 and preceding paper). Here we have used Southern blotting to analyse in greater detail the proviral DNA present in several mutant lines of D. melanogaster produced by microinjection of intact RSV or plasmid DNA containing the viral insert. In certain populations of flies, RSV provirus was found to be incorporated into cellular DNA, and in one mutant family the unintegrated form of plasmid DNA was identified. Generally, the presence of injected genetic material in fly cells correlated with morphological changes in Drosophila.
Subject(s)
Avian Sarcoma Viruses/genetics , DNA, Viral/genetics , Drosophila melanogaster/genetics , Mutation , Animals , Base Sequence , DNA Restriction Enzymes , DNA, Viral/isolation & purification , Drosophila melanogaster/embryology , Embryo, NonmammalianABSTRACT
Retroviral proviruses and the transposable elements of eukaryotic genomes are structurally similar. The biological significance of eukaryotic transposable elements has not been examined extensively but it is known that, like prokaryotic transposons, these elements can induce mutations in adjacent genes and cause their transposition. It is of interest to determine whether retroviral proviruses have the same mutagenic and gene transposing ability as transposable elements, particularly because the retrovirus genome is assumed to have originated from transposable elements of lower eukaryotes. The transfer of DNA sequences into animal zygotes or embryos by microinjection is a promising experimental approach for eluxidating their functions: when foreign DNAs were introduced into a mouse germ line, mutations were induced and at least in some mice, the mutation was caused by the insertion of a retroviral sequence. We have introduced Rous sarcoma virus (RSV) DNA into a germ line of Drosophila melanogaster, and describe here the resultant genetic effects.