Spermatozoa contain the genetic information required for the hereditary transmission of the characteristics. Of the species and the molecular machinery required for the preservation, Transport and introduction of this information into the ovum. The micrographs on the opposite page show the morphology. The guinea pig and rooster sperm, The two species that we have used primarily in our research. The tiny volume of the sperm nuclei and their stylized hydrodynamic shape can be seen in them. What structural changes in germ cell chromatin allow DNA to pack into such a small nuclear volume? How is the integrity of the genetic message carried by sperm preserved? What mechanisms control the expression of genetic information responsible for Although similar surface the differentiation process of testicular cells? And how is the differentiation program subsequently erased to give rise to the genetic message of the spermatozoa.
The sperm, one of the most highly specialized cells in the body
A true tabula rasa that transmits all the characteristics of the species? To contribute to the resolution of these and other questions regarding the molecular biology of spermatogenesis, we began our research work in this field in the early 1970s. Since then, Our main objective has been to investigate the relationship between changes in the composition, BUILDING MATERIALS, HARDWARE, GARDEN SUPPLY, AND MOBILE HOME DEALERS business email list structure and functional activity of chromatin throughout spermatogenesis. When normal human cells are grown in vitro, They eventually lose their functional capacity and stop dividing. The time in which this happens could represent the maximum limit of human life span. Leonard The length of human life has not increased significantly for millennia. For most people the biblical ninety years are still the upper limit. What has changed, at least in developed countries, is global life expectancy.
Cell biology of human aging
Improved living conditions and advances in medicine, particularly the control of infectious diseases, have only allowed more people to reach what appears to be the maximum life span. Even if the main causes of death were eliminated, the duration of human life would remain at about ninety or one hundred years. The explanation is that, even when death may occur as a consequence of cardiovascular diseases or cancer, Such diseases derive from the Sale Lead normal aging degeneration of the arterial walls or the immune system. The fundamental cause of death in the last years of life is the increase in the body’s vulnerability to diseases or accidents, a vulnerability attributable to the inexorable decline in functional capacity after the age of thirty, a decrease that Bernard L. Estimated to be round 0.8 percent per year. In addition, the Englishman Benjamin , an expert in an insurance company,
