Male cell

Uncultured cells have also been used to a limited extent for fetal sex determination. This Is possible because the cells can be appropriately stained and examined for the presence of sex chromatin, characteristic of female cells, and for the fluorescent Y-body, characteristic of male cells (33,34). However, these cytologic techniques are not completely reliable, and It Is still desirable to determine fetal sex by direct chromosome analysis (35). 

Bacteriophage T7 Bacteriophage T7 and its close relative T3 are relatively small DNA viruses that infect Escherichia coli. (Some strains of Shigella and Pasteurella are also hosts for phage T7.) The virus particle has an icosahedral head and a very small tail. The virus particle is fairly complex, with S different proteins in the head and 3-6 different proteins in the tail. One tail protein, the tail fiber protein, is the means by which the virus particle attaches to the bacterial cell surface. Only female cells of Escherichia coli can be infected with T7 male cells can be infected but the multiplication process is terminated during the latent period. 

In addition to the 22 pairs, a female cell contains two X chromosomes and a male cell contains an X and a Y chromosome. When a female egg (carrying an X chromosome) combines with male sperm having an X chromosome, a female offspring is born. When the egg combines with a sperm having a Y chromosome, a male offspring results. 

X chromosome and one Y chromosome, which has different genes than the X chromosome. Yet the genes on the X chromosome must, for the most part, be equally active in female cells (XX) and male cells (XY). To achieve this balance, one of the X chromosomes in female cells is chemically modified and condensed into a very small mass called a Barr body, which is inactive and never transcribed. 

Partial chromosome transfer from a male cell transforms the F cell into a partial diploid (merozy-gote) containing double the usual number of some of the genes. Within this partial diploid genetic recombination between the two chromosomes takes place (Fig. 

In our laboratory we have attempted, so far without success, to chemically induce reverse mutations to the wild-type phenotype and a corresponding restoration of the enzyme activity in fibroblasts from two Lesch-Nyhan patients. On the other hand, forward mutation in normal human male cells to the mutant phenotype has been induced with X-rays (Albertini and De Mars, 1970). 

The Phycomycetes are those in which the vegetative structure normally comprises mycelia which are not divided into cells by cross-walls. The group is subdivided according to the mode of sexual reproduction. Thus those that have male and female sex cells of the same shape and size are termed Zygomycetes, e.g. Mucor and Rhizopus (bread moulds). Those that have female sex cells which are larger than the male cells are Oomycetes, e.g. Pseudoperonospora (downy mildew of hops). 

F Cell A cell having an F plasmid, called donor or male cell. 

Giansanti M.G., Bonaccorsi S., and Gatti M. 1999. The role of anillin during meiotic q okinesis of Drosophila males. /. Cell Sci. 112 2323-2334. 

---