he data on rhythmic processes in early embryogenesis coinciding with cell divisions are considered. Possible mechanisms which determine the rhythm frequency and are its motive power are discussed, as well as the role of individual rhythmic processes in the regulation of consecutive cell cycle events. A suggestion is put forward that these rhythmic processes are transformed during subsequent development in circum-hour rhythms of some biochemical, physiological and biophysical processes discovered in the cells and organs of adult organism.

Animals↗

PubMedDate not supplied

[The creation of genetic cryobanks and the use of the methods of developmental biology as a means for preserving rare animal species. I. The cryopreservation of the sperm of wild mammals].

A review of published data on cryoconservation of the sperm of wild animals. Progeny of females inseminated with frozen-thawed sperm was obtained in 21 species and subspecies, including 11 from the Red Data Book. Mobility of the spermatozoa after freezing-thawing was estimated in 74 species, including 13 from the Red Data Book. Studies on cryoconservation have recently been carried out predominantly on the Red Data Book species, as well as the species intensely bred in the countries, where several founder individuals were introduced (deer in Australia and New Zealand). Large zoos and some universities in the USA, Canada and Great Britain are the main research centers.

Animals↗

PubMedDate not supplied

[The creation of genetic cryobanks and the use of the methods of developmental biology as a means for preserving rare animal species. II. The obtaining and cryopreservation of the embryos of wild mammals].

A review of published data on obtaining, cryoconservation, and subsequent development of the embryos of wild animals. Development of the embryos until birth after freezing-thawing and transplantation of the embryos to recipient females was followed in eight species. Studies are mostly carried out in the zoos and some universities of USA, Canada, and UK. The Red Data Book species and artificially bred species are the main objects. In these studies, diverse methods of developmental biology were used: induced oocyte maturation, artificial fertilization and cultivation of the embryos in vitro, transplantation of the embryos to foster mothers of the same or closely related species, and obtaining of chimeras.

Animals↗

PubMedDate not supplied

[The conservation of the genetic resources of deer (Cervidae) by the cryopreservation of their germ cells].

Necessity of organization of a cryobank for the sperm of some taxa has been substantiated on the basis of the published data and authors' results concerning the state of genetic resources of the family Cervidae in Russia. A task has also been set to elucidate some factors that may affect the success of cryoconservation, such as the age of male donors; season; duration of sperm storage before and after freezing, including long-term storage; and the possibility of obtaining of sperm from perished males. Results are provided on the influence of these factors of the quality of spermatozoa obtained on three species of the Cervidae.

Animals↗

PubMedDate not supplied

[The creation of genetic cryobanks and the use of the methods of developmental biology as a means for preserving rare animal species. III. The outlook, problems and limits: selection, modifications and mutations].

A review of our own and literature data about perspectives, problems and limitations in the use of cryoconservation techniques and methods of developmental biology for the conservation of genetic resources is presented. It is demonstrated that the use of these methods may result in the selection and possibly leads to modifications and mutations in germ cells and embryos and in this way may change the genetic structure of restored populations as compared with the original ones. The need to improve current techniques of cryoconservation and accompanying biotechnological procedures in order to abolish these undesirable genetic effects is emphasized.

Animals↗