Ploidy diploid

Marked disturbances in the distribution of ploidy (diploid and tetraploid nuclei) have been observed in the livers of male Sprague-Dawley rats fed a dietary concentration of 100 ppm mirex (equivalent to 5 mg/kg/day) for 13 months (Abraham et al. 1983). Mirex selectively reduced the number of tetraploids with the most significant reduction noted in hepatocellular carcinomas however, nuclei in the areas adjacent to these tumors were also primarily composed of diploids. These data should be interpreted with caution since isolation of nuclei from tumors is difficult and because "of the fantastic variety of forms that tumor nuclei assume" (Smuckler et al. 1976). Similarly, the relevance to humans is not clear since human liver is mainly composed of diploid cells (99%) and contains few tetraploids (Adler et al. 1981). 

Johnson, A. A. T., Nault, B. A., Veilleux, R. E. (2003). Transmission of a Bacillus thuringiensis eiy3Aa transgene from diploid to tetraploid potato using 4x-2x hybridization effeet of ploidy inerease on transgene expression and implieations for TPS hybrid produetion. Plant Breeding, 122,223-228. 

Cytogenetic abnormalities are frequent in most tumor types and are often associated with tumor characteristics or patient outcome. Altered DNA ploidy (copy number changes) in the cancer genome was described in the 1960s when it was demonstrated that bladder and prostate cancer patients with diploid or tetraploid tumor nuclei had a longer survival rate than patients with triploid or hexaploid tumor nuclei (19). 

MEIOSIS The process by which a eukaryotic cell nucleus (in which the DNA has been replicated only once) undergoes two coordinated divisions that yield four cells, each having ploidy half that of the original cell in higher animals, meiosis provides for the production of haploid sperms or eggs from diploid spermatocytes or oocytes. (See also MITOSIS)... 

PLOIDY Refers to the number of sets of chromosomes in a cell or organism—1 set in monoploids (haploids), 2 in diploids, 3 in triploids, 4 in tetraploids, etc. 

The existence of different morphotypes, two ploidy levels related to phase changes, and the ability of both haploid and diploid stages to divide mitotically (Kornmann 1955 Rousseau et al. 1994 Vaulot et al. 1994), support the existence of a haploid-diploid life cycle in P. globosa. In such life cycles, both haploid and diploid stages are related by sexual processes, meiosis and syngamy, and both are capable of mitotic division (Fig. 3 ... 

The DNA ploidy is expressed by the DNA index (DI). For DI = 1, the DNA is normal and classified as DNA diploid for DI 1, the DNA is abnormal and is classified as DNA aneuploid, a state usually associated with neoplastic cells. On the basis of these parameters, additional parameters for comparative estimation were calculated, including the proliferation index (Pl -SxG x Mf to Gy phase ratios and the coefficient of variation (CV). The normal values... 

The client s DNA ploidy tests show diploid cells. 

Two approaches are currently known for obtaining transformed root cultures of different ploidy level transformation of autopolyploid intact plants and in vitro polyploidization of transformed root cultures obtained from diploid intact plants. 

The approach of in vitro polyploidization of transformed root cultures obtained from diploid intact plants is presented schematically on Fig. 7.6. Most often, for in vitro polyploidization of transformed root culmres, colchicine 31 and oryzalin 32 are used in concentrations of 0.002-0.005% and 0.0002-0.0005%, respectively. Our experience shows that about 8-10% of the newly obtained lines are of different ploidy than the source line. 

Many years of research in our laboratory [24, 30, 89, 90, 114] on the impact of artificial pol3 ploidy on the biosynthesis of tropane alkaloids from diploid- and tetraploid-transformed root cultures of D. stramonium L. have revealed that induced polyploidy makes it possible to obtain higher yields of target metabolites as well as to achieve biosynthesis of new biologically active substances that are normally not synthesized in the intact plants (Table 7.3). The comparative analysis of the alkaloid profile of diploid and tetraploid intact D. stramonium L. plants and transformed roots derived from them (Table 7.3) established 39 alkaloids, 33 of which were identified. 

D. stramonium L. plants accumulate various alkaloids in different plant organs. However, no differences are detected in the alkaloid profiles of diploid and tetraploid plants. There are differences in the alkaloid spectra of plants of different ploidy levels in the minority alkaloids (less than 1% of the ion current). 

It should be noted that the two ploidy levels of the transformed root cultures of D. stramonium L. show significant differences as regards the spectrum of the biosynthesized alkaloids. Unlike the diploid, tetraploid-transformed roots biosynthesized ten alkaloids. One of them (entry 15, Table 7.3) was not detected in the diploid root culture of D. stramonium L. The pharmacologically active alkaloid hyoscyamine 1 is the principal alkaloid biosynthesized by both root cultures at 78.8% and 56.6% of the total ion ciuxent in the diploid and tetraploid-transformed roots of D. stramonium L., respectively (entry 9, Table 7.3). In contrast to diploid roots, which accumulate 7.12% apoatropine, the tetraploid-transformed root culture biosynthesize 3-acetoxytropane (28.4%) as a second... 

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