introduction: mouse embryos can successfully be frozen with sucrose and propandiol. however, different developmental stages of mammalian embryos have shown to have various capacities to undergo freeze-thawing procedure. in the present study, the ability of 1,2,4 and 8-ell mouse embryo to tolerate the freeze-thawing procedure was investigated and the effect of this procedure on the further in vi...

Recent reports of strong selection of mitochondrial DNA (mtDNA) during transmission in animal models of mtDNA disease, and of nuclear transfer in both animal models and humans, have important scientific implications. These are directly applicable to the genetic management of mtDNA disease. The risk that a mitochondrial disorder will be transmitted is difficult to estimate due to heteroplasmy-th...

We have studied the origin of muscle satellite cells in embryos of Xenopus laevis. Fate mapping at the open neural plate stage was carried out using orthotopic grafts from transgenic embryos expressing GFP. This shows that most satellite cells originate from the dorsolateral plate rather than from the paraxial mesoderm. Specification studies were made by isolation of explants from the paraxial ...

Greenwood et al.1) used the expression, "experimental epidemiology" for the laboratory study on animal diseases analogous to human complaints. A controlled experiment in which one variable is manipulated is essential in order to test a hypothesis of disease etiology. An animal model of human diseases has been used extensively in order to discover the mechanism that spreads infectious diseases. ...

The Smith-Lemli-Opitz syndrome-affected fetus presents a deficiency in delta7-dehydrocholesterol reductase, the last enzymatic step in the cholesterol biosynthesis pathway. Development of the abnormal human fetus takes place in a normal environment as the heterozygous mother's cholesterolemia remains normal. An animal model for this disease has been obtained from the offspring of pregnant rats ...

Chimeras, organisms composed of two genetically distinct types of cells, have now been routinely created in the laboratory: Researchers are experimenting using sheep as a source of human liver transplant, and scientists have developed a line of pigs that have pig blood cells, human blood cells and a combination of both. Investigators have also created mice with a human immune system and are cur...

Fluorescent protein tags are fundamental tools used to visualize gene products and analyze their dynamics in vivo. Recent advances in genome editing have expedited the precise insertion of fluorescent protein tags into the genomes of diverse organisms. These advances expand the potential of in vivo imaging experiments and facilitate experimentation with new, bright, photostable fluorescent prot...

Inductive interactions play a major role in the diversification of cell types during vertebrate development. These interactions have been extensively studied in amphibian embryos (usually Xenopus laevis) where the earliest is mesoderm induction, in which an equatorial mesodermal rudiment is induced from the animal hemisphere under the influence of signal from the vegetal hemisphere. The molecul...

Most eggs in the animal kingdom establish a primary, animal-vegetal axis maternally, and specify the remaining two axes during development. In sea urchin embryos, the expression of Nodal on the oral (ventral) side of the embryo is the first known molecular determinant of the oral-aboral axis (the embryonic dorsoventral axis), and is crucial for specification of the oral territory. We show that ...

This paper uses cattle as a model to provide an overview of the hazards involved in the transfer of in vivo-derived and in vitro-produced embryos. While scientific studies in recent decades have led to the identification of pathogens that may be associated with both in vivo- and in vitro-derived embryos, those studies have also been the basis of appropriate disease control measures to reduce th...