Daughter cell

Binary fission During binary fission, a single cell divides transversely to form two new cells called daughter cells. Both daughter cells contain an exact copy of th geneticinformation contained in the parent cell. 

Nucleus The nucleus is separated from the cytosol by a double membrane, the nuclear envelope. The DNA is complexed with basic proteins (histones) to form chromatin fibers, the material from which chromosomes are made. A distinct RNA-rich region, the nucleolus, is the site of ribosome assembly. The nucleus is the repository of genetic information encoded in DNA and organized into chromosomes. During mitosis, the chromosomes are replicated and transmitted to the daughter cells. The genetic information of DNA is transcribed into RNA in the nucleus and passes into the cytosol where it is translated into protein by ribosomes. 

DNA replication yields two DNA molecules identical to die original one, ensuring transmission of genetic information to daughter cells widi exceptional fidelity. 

Microbial growth was discovered with replication of each cell to three daughter cells. With the growth data define the mean time for the cell divisions. Table E.10.1 shows the cell dry weight increases with culture incubation time. 

The survival of cells depends on their ability to transmit the genetic information properly onto two daughter cells. The faithful transmission depends on proper... 

At the end of mitosis after re-establishment of the cell nuclei the cytoplasm is divided resulting in two independent daughter cells. 

All mature blood cells arise from primitive hematopoietic cells in the bone marrow, the pluripotent stem cells. Approximately 0.1% of the nucleated cells of the bone marrow are pluripotent stem cells and approximately 5% of these cells may be actively cycling at any one time. The stem cell pool maintains itself through a process of asymmetrical cell division when a stem cell divides, one daughter cell remains a stem cell and the other becomes a committed colony-forming cell (CFC). The proliferation and differentiation of CFCs are controlled by hematopoietic growth factors. The hematopoietic growth factors stimulate cell division, differentiation and maturation, and convert the dividing cells into a population of terminally differentiated functional cells. 

During telophase, a midbody forms between the separating daughter cells (see Figure 4), and disassembly of the remaining spindle microtubules and kinetochores takes place. 

Cytokinesis (cell division) in animal cells involves the progressive formation in telophase of a furrow between the two daughter cells in the equator of the mitotic spindle. Immunofluorescent staining of the cortical cytoplasm at the site of the contraction ring reveals an abundance of actin as well as myosin, a-actinin, and filamin (Fishkind and Wang, 1995). Cytokinesis is highly sensitive to actin-myosin inhibitors such as cytochalasin and phalloidin. 

The cytoskeleton undergoes extensive reorganization during mitosis, and is responsible for the equipartition of a diploid set of chromosomes to each daughter cell (McIntosh and Koonce, 1989 Wadsworth, 1993). 

Cytokinesis is the separation of daughter cells at the completion of the microtubule directed separation of duplicate chromosomes at mitosis or meiosis. This is usually accomplished by a purse string mechanism, whereby daughter cells become separated by the gradual constriction of a structure composed of actin microfilaments and myosins-II (Fujiwara and Pollard, 1976 Satterwhite and Pollard, 1992). 

Fig. 2.4 The budding pattern in haploid and diploid Saccharomyces cerevisiae. The original cell which formed a bud is the mother (M). The daughter cell (D) is shown remaining attached as might be the case in i colonies growing on the surface of agar.

Fig. 2.5 Cell cycles resulting in yeast-form cells, pseudohyphae and hyphae. In many respects the cell cycle of pseudohyphal cells is similar to that of yeast-form cells, except that in pseudohyphae G2 is prolonged, thus larger daughter cells are produced which are identical in size to the mother cell. Hence, mother and daughter are both sufficiently large to start the next cell cycle and so bud synchronously. In hyphae the apical cell becomes progressively longer. The diagram is reproduced from the review of Kron Gow (1995) with the permission of Current Opinion in Cell Biology.

Integration of the prophage into the bacterial ehromosome ensures that, on cell division, each daughter cell will acquire the set of viral genes. 

The chromatid separation process has also remained mysterious. It is an autonomous process that does not direcdy depend on the mitotic spindle (Wilson 1925, Mazia 1961). This is most vividly seen in cells whose spindles have been destroyed by spindle poisons such as colchicine. In many organisms, in particular in plant cells, the cell cycle delay induced by colchicine is only transient and chromatids eventually split apart in the complete absence of a mitotic spindle (Mole-Bajer 1958, Rieder Palazzo 1992) (Fig. 2). Mitosis in the presence of colchicine or colcemid (known as c-mitosis) leads to the production of daughter cells with twice the normal complement of chromosomes. This process is routinely used for manipulating plant genomes and may contribute to the therapeutic effects of taxol in treating breast cancer. 

Broadus J, Fuerstenberg S, Doe CQ 1998 Staufen-dependent localisation of prospero mRNA contributes to neuroblast daughter-cell fate. Nature 319 792-795... 

Ikeshima-Kataoka H, Skeath JB, Nabeshima Y, Doe CQ, Matsuzaki F 1997 Miranda directs Prospero to a daughter cell during Drosophila asymmetric divisions. Nature 390 625—629 Jan YN, Jan LY 1998 Asymmetric cell division. Nature 392 775-778... 

Chia What is clear is that the neurons that are made look normal. If these abnormalities are occurring during mitosis, the daughter cells produced still appear normal. 

Chia No, what determines fate in the daughter cells is whether or not they inherit the cell fate determinants which are normally localized as basal crescents. If the crescents of cell fate determinants are not fixed, they will not always overlie one of the spindle poles. Consequently, their segregation to the daughter cells will not always be asymmetric. 

The superficial cells are irregular arrays of polygonal cells with a diameter of 40-60 pm and a thickness of 2-6 pm each. These cells, the most differentiated cells of the epithelium, possess microvilli in their apical surfaces, which are covered with a glycocalyx. It is, however, controversial whether mucus exists on their surface [58,59], As cell division occurs in the basal cells of the cornea, the daughter cells move toward the surface while becoming more differentiated. As the daughter cells migrate toward the outermost layer, the superficial cells are... 

By definition, cell mitosis results in two daughter cells, identical to each other and to the parent cell. So in order to break symmetry, bit 1 in the state vector is set to 1 in one cell, while it is set to the reverse (0) in the other cell. The first 3 bits of the state vector are prespecified as the ones indicating cell type — in reverse. For example, a cell with state vector = 001110 has type 001-reversed, which is 100 or 4 (in decimal). This entails that the first division inevitably results in two cells of different types with state vectors 000100 and 100100, respectively. 

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