Ploidy tetraploid

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). 

Tetraploid Tetraploid is a term used to describe cells with double the amount of DNA normal for a particular species. Malignant cells are frequently of the tetraploid type. Distinguishing this type of ploidy from normal G2 or M cells or, indeed, from clumps of two cells can be difficult with flow cytometry. 

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. 

Ploidy levels of the resulting progenies were mixed, as in any chemical induction, because embryonic development is not uniform between oocytes and thus different ploidy levels were achieved. Pair matings also showed different results in terms of representation of ploidy classes, indicating parental influences. A difference in size between ploidy levels, as observed in oyster by McCombie et al (2005a), was used to concentrate tetraploid offspring into pseudocohorts as they developed. 

As success is variable, the production of tetraploid mussels requires ploidy testing, which can be made by flow cytometry. Early-stage batches have to be tested destructively on small samples of larvae. In BLUE SEED project trials, the technique produced tetraploidy in D-larvae in five separate experiments, covering both M. edulis and M. galloprovincialis, with tetraploid percentages between 18% and >60%, based on samples of 50-200 ground larvae. Later, non-destructive tests could be made on juveniles and adults by biopsy under MgCL anaesthesia. It was found that... 

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... 

By counting chromosomes, different levels of the ploidy [e. g., n = haploid, 2n = diploid (the normal two sets of chromosomes), 4n = tetraploid, 6n =... 

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