Kinetoplasts

A simple assay for the detection of the malarial parasite Plasmodium falciparum involves saponin lysis of blood sample and membrane filtration followed by amplification of the consensus sequence of eight 21-bp repeats. This procedure has been successfully used in the field (F2). A PCR assay targeting kinetoplast DNA sequences of Leishmania species was also successfully tested in the field (F2). Molecular methods for the detection of toxoplasma gondii and several other parasites have been reviewed (F2). 

Diamidines (pentamidine) Binds to kinetoplast DNA Affects synthesis or structure... 

Pentamidine (Pentam 300) binds to DNA and may inhibit kinetoplast DNA replication and function. It also... 

No evidence has been found for the mitosomal genome in any organism so far. An earlier study on E. histolytica reported the presence of DNA in Entamoeba mitosomes (Ghosh et al. 2000) and synonymized these organelles with DNA-containing structures named kinetoplast-like organelles (EhKO) (Orozco et al. 1997). However, work by Leon-Avila and Tovar (2004) later showed that EhKO and mitosomes are not related structures. Moreover, in situ nick translation coupled with immunofluorescence microscopy failed to detect the presence of DNA in Entamoeba mitosomes (Leon-Avila and Tovar... 

Eukaryotic cells also have organelles, mitochondria (Fig. 24-6) and chloroplasts, that contain DNA. Mitochondrial DNA (mtDNA) molecules are much smaller than the nuclear chromosomes. In animal cells, mtDNA contains fewer than 20,000 bp (16,569 bp in human mtDNA) and is a circular duplex. Each mitochondrion typically has two to ten copies of this mtDNA molecule, and the number can rise to hundreds in certain cells when an embryo is undergoing cell differentiation. In a few organisms (trypanosomes, for example) each mitochondrion contains thousands of copies of mtDNA, organized into a complex and interlinked matrix known as a kinetoplast. Plant cell mtDNA ranges in size from... 

The kinetoplast DNA of trypanosomes (Fig. 5-16) consists of thousands of catenated circular DNA molecules. Among these the smaller minicircles always contain the sequence GGGGTTGGTGTAat their origins of replication. The minicircles are individually removed from the mass prior to replication. The two progeny circles are then both recatenated into the mass.462... 

Shermilamines B (37) and C (38) (and also diplamine 46) showed dose-dependent inhibition of proliferation in HCT cells in vitro and inhibited the topoisomerase (TOPO) II-mediated decatenation of kinetoplast DNA (kDNA) in a dose-dependent manner [41]. These results suggest a possible cytotoxicity mechanism for these compounds. Furthermore, shermilamine B also displayed cytotoxicity against KB cells [43] and was reported as a potent regulator of cellular growth and differentiation, affecting cAMP-mediated processes [44]. 

D6. Deng, J. S., Sontheimer, R. D., Lipscomb, M. F., and Gilliam, J. N., The binding of antihistone antibodies to Crithidia luciliae kinetoplasts is growth cycle-dependent. Arthritis Rheum. 28, 163-168 (1985). 

J4. Jonsson, J., and Norberg, R., Effect of enzyme treatment of Crithidia luciliae on the reactivity of its kinetoplast with anti-DNA sera. Scand. J. Rheumatol. 5, 221-226 (1976). 

Burkhoff, A. Tullis, T. D. The unusual conformation adopted by the adenine tracts in kinetoplast DNA. Cell 1987 48 935-943. 

Diekmann, S. Wang, J. C. On the sequence determinant and flexibility of the kinetoplast DNA fragment with abnormal gel electrophoretic mobilities. J. Mol. Biol. 1985 186 1-11. 

In other protozoa, such as the genus Trypanosoma, the organisms have a kinetoplast whose DNA molecule contains the information to produce a mitochondrion once in its next... 

In trypanosomatids the mitochondrial DNA [kinetoplast DNA (kDNA)] consists of two sets of circular molecules, namely 20-50 maxicircles (20-39 kb in size) and 5000-10000 interlocked minicircles (0.5-2.5 kb in size). The maxicircles are analogous... 

FIG. 13.4 Longitudinal section of an L. mexicana amastigote. Note the abundant megasomes (Is) and the kinetoplast (kp) at the base of the short flagellum (f). Also shown and identified are the flagellar pocket (fp), the nucleolus (nl), chromatin (chr), and two sections through the single mitochondrion (m). (Reprinted with permission from ref 53.)... 

The class Kinetoplastida is named after its unusual mitochondrial feature, the kineto-plast (Fig. 13.4). The kinetoplast is the organized network of mitochondrial DNA (or kDNA) which is localized to one end of the single mitochondrion, near the flagellar... 

FIG. 13.6 Kinetoplasts of T. hrucei connected to basal bodies. Flagella were prepared by detergent lysis and cytoskeletal depolymerization. The flagellar are viewed by phase contrast and the kDNA by DAPI fluorescence. DAPI is a fluorescent dye which binds to DNA. (Reprinted with permission from ref. 64.)... 

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