Diploid, term

Vitamins and lipids are often required for animal cells to grow in serum-free medium. Phosphoethanolamine and ethanolamine are key additives that facilitate the growth of the mammary tumor cell line 64024 (Kano-Sueoka and Errick, 1981). In addition, ethanolamine promotes the growth of human lymphocytes and mouse hybridoma cells. Short-term cultures of human diploid lung and foreskin fibroblasts grow in medium that includes among its supplements soybean lecithin, cholesterol, sphingomyelin, and vitamin E. 

Peripheral blood cultures are stimulated to divide by the addition of a T cell mitogen such as phytohaemagglutinin (PHA) to the culture medium. Mitotic activity is at a maximum at about 3 days but begins at about 40 h after PHA stimulation and the chromosome constitution remains diploid during short-term culture (Evans and O Riordan, 1975). Treatments should commence at about 44 h after culture initiation. This is when cells are actively proliferating and cells are in all stages of the cell cycle. They should be sampled about 20 h later. In a repeat study the second sample time should be about 92 h after culture initiation. Morimoto et al. (1983) report that the cycle time for lymphocytes averages about 12-14 h except for the first cycle. 

Aneuploidy The chromosomal constitution of cells which deviate from the normal by the addition or subtraction of chromosomes or chromosome pairs. In a normally diploid cell the loss of a chromosome pair is termed nullisomy (symbol 2N-2), the loss of a single chromosome is monosomy (symbol 2N-1), the addition of a chromosome pair is tetrasomy (symbol 2N+2), the addition of a single chromosome is trisomy (symbol 2N+1). [nih]... 

These three changes take several honrs, and the whole process is termed capacitation. These changes allow a sperm to reach the plasma membrane of the ovnm. Then the plasma membrane of the sperm fnses with that of the ovum, the head is engulfed within the membrane of the ovum and the head, and only the head, enters the ovum. Within the ovum, the nucleus of the sperm is released and the two nnclei fuse. A diploid zygote is the result. 

Careie, A., Conti, G, Conti, L. Crebelli, R. (1985) Assays in Aspergillus nidulans for the indnction of forward-mutation in haploid strain 35 and for mitotic nondisjunction, haploidization and crossing-over in diploid strain PI. In Ashby, J., de Serres, F.J., Draper, M., Ishidate, M., Jr, Margolin, B.H., Matter, B.E. Shelby, M.D., eds. Progress in Mutation Research, Volume 5, Evaluation of Short-Term Tests for Carcinogens. Report of the International Programme on Chemical Safety s Collaborative Study on in vitro assays, Amsterdam, Elsevier Science, pp. 307-312... 

PH A-induced lymphocytes provide an ample source of material for gene mapping primarily because of the ease of handbag short-term cultures, but also because the lymphocytes retain their normal diploid karyotype for a long time in culture. 

G0/G1 In flow cytometry, the term refers to cells that have the 2C (diploid) amount of DNA and are therefore either not cycling (GO) or have just completed cytokinesis and have not yet begun again to make more DNA in preparation for a new cycle (Gl). 

Heteroploid The term given to a cell culture when the cells comprising the culture possess nuclei containing chromosome numbers other than the diploid number. This is a term used only to describe a culture and is not used to describe individual cells. Thus, a heteroploid culture would be one that contains aneuploid cells. 

The number of chromosomes normally present in a plant are arranged in pairs so that the complete set is composed of 2 haploid (N) sets and organisms containing them are termed diploid and represented as 2N. Most normal plants are diploid. 

The short-term response of cells to antimetaboUtes is also controlled by p53. Cells lacking p53 die more rapidly than those with p53 function. Normal diploid fibroblasts with wUd-type p53 arrest in Go for extended periods of time in the case of PALA. Removal of the drug allows reentry in the cell cycle. In this case, it is presumed that the imbalance of nucleotide pools is the trigger for p53 induction and cells do not necessarily enter S phase to initiate this response. In those cells... 

Meiotic recombination in diploid organisms requires extensive sequence homology between the recombining partners and is called homologous recombination. This term also describes certain recombinational events between bacterial chromosomes. Most bacterial homologous recombination processes share a common requirement for the RecA protein or its counterpart. 

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