Recurrent isochromosome 21 and multiple abnormalities in a patient suspected of having acute myeloid leukemia with eosinophilic differentiation -- a rare case from South India.
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Novel acridine-based N-acyl-homoserine lactone analogs induce endoreduplication in the human oral squamous carcinoma cell line SAS.
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The cytotoxicity of novel acridine-based N-acyl-homoserine lactone (AHL) analogs was investigated on the human oral squamous carcinoma cell line SAS. One analog induced G2/M phase arrest at 5.3-10.6 microM and induced polyploidy at a higher dose (21.2 microM). Importantly, treatment of SAS cells with a combination of the AHL analog and the Jun N-terminal kinase (JNK) inhibitor, SP600125, prevented mitosis and induced polyploidy. The AHL analog synergized with X-irradiation to inhibit clonogenic survival of SAS cells; however, its radiosensitizing effects were relative to not X-irradiation-induced apoptosis but mitotic failure following enhanced expression of Aurora A and B. These results suggest that the active AHL analog showed growth-suppressive and radiosensitizing effects, which involve polyploidy followed by G2/M accumulation and atypical cell death in the SAS cell line. (+info)
Endoreduplication preferentially occurs at the proximal side of the abscission zone during abscission of tomato leaf.
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Evidence for karyoplasmic homeostasis during endoreduplication and a ploidy-dependent increase in gene transcription during tomato fruit growth.
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Endopolyploidy is a widespread process that corresponds to the amplification of the genome in the absence of mitosis. In tomato, very high ploidy levels (up to 256C) are reached during fruit development, concomitant with very large cell sizes. Using cellular approaches (fluorescence and electron microscopy) we provide a structural analysis of endoreduplicated nuclei at the level of chromatin and nucleolar organisation, nuclear shape and relationship with other cellular organelles such as mitochondria. We demonstrate that endopolyploidy in pericarp leads to the formation of polytene chromosomes and markedly affects nuclear structure. Nuclei manifest a complex shape, with numerous deep grooves that are filled with mitochondria, affording a fairly constant ratio between nuclear surface and nuclear volume. We provide the first direct evidence that endopolyploidy plays a role in increased transcription of rRNA and mRNA on a per-nucleus basis. Overall, our results provide quantitative evidence in favour of the karyoplasmic theory and show that endoreduplication is associated with complex cellular organisation during tomato fruit development. (+info)