Further Ultrastructural Characterization of the Intranuclear Ring-Shaped Bodies of the Plant Lacandonia schismatica

Agredano-Moreno, Lourdes Teresa; González-Jiménez, Marco Antonio; Segura-Valdéz, María de Lourdes; Ubaldo, E; Ramos, Clara H.; Martı́nez, Esteban; Jiménez‐García, Luis Felipe

doi:10.1006/jsbi.2001.4416

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…2 and 5). In addition, nuclear ring-shaped bodies have also been observed in the nucleoplasm of G. biloba and other species (Agredano-Moreno et al, 2001). However, clusters of 15 nm diameter granules characterized by interchromatin granules clusters have not been observed so far.…”

Section: Resultsmentioning

confidence: 99%

“…Lacandonia schismatica is an endemic and rare plant (Diario Oficial, 1994) from the Selva Lacandona, Chiapas in Mexico, whose most prominent characteristic is the spatial inversion of its sexual organs (Márquez-Guzmán et al, 1989;Martínez and Ramos, 1989). Recently, as part of an effort to understand its biology, we have been studying several aspects of its cell biology including the nuclear structure (Jiménez-García et al, 1992Agredano-Moreno et al, 1994, 2001Jiménez-García and Fragoso-Soriano, 2000;Agredano-Moreno and Jiménez-García, 2001). The cell nucleus of L. schismatica is reticulated and as reported, it is associated to a novel 32 nm diameter nuclear ribonucleoprotein (RNP) particle named Lacandonia granule.…”

Section: Introductionmentioning

confidence: 99%

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Lacandonia granules are present in Ginkgo biloba cell nuclei

Jiménez-Ramírez

Agredano-Moreno

Segura-Valdéz

et al. 2002

Biology of the Cell

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Lacandonia schismatica is a rare flowering plant with the sex organs spatially inverted. Several aspects of its cell biology are now known. Interestingly, within the cell nucleus, the chromatin is reticulated and it is associated to a novel structure named Lacandonia granules, a very abundant ribonucleoprotein particle showing similarities to perichromatin and Balbiani ring granules, which are involved in nuclear mRNA metabolism. To see whether these particles are present in other plants, we study the nucleus of Ginkgo biloba, a non-flowering plant. Light, electron and atomic force microscopy show that the cell nuclei of G. biloba are reticulated. Ultrastructural analysis showed that in the nucleoplasm, abundant intranuclear particles 32 nm in diameter are present. The EDTA regressive staining suggested that they contain RNA. Ultrastructural in situ hybridization confirmed the presence of RNA in these particles. Therefore, we conclude that the nuclei of G. biloba are reticulated and contain Lacandonia granules. We suggest that these particles may also be present in other plants.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lacandonia granules are present in Ginkgo biloba cell nuclei

Jiménez-Ramírez

Agredano-Moreno

Segura-Valdéz

et al. 2002

Biology of the Cell

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The polypeptides COX2A and COX2B are essential components of the mitochondrial cytochrome c oxidase of Toxoplasma gondii

Morales-Sainz

Escobar-Ramírez

Cruz-Torres

et al. 2008

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Two genes encoding cytochrome c oxidase subunits, Cox2a and Cox2b, are present in the nuclear genomes of apicomplexan parasites and show sequence similarity to corresponding genes in chlorophycean algae. We explored the presence of COX2A and COX2B subunits in the cytochrome c oxidase of Toxoplasma gondii. Antibodies were raised against a synthetic peptide containing a 14-residue fragment of the COX2A polypeptide and against a hexa-histidine-tagged recombinant COX2B protein. Two distinct immunochemical stainings localized the COX2A and COX2B proteins in the parasite's mitochondria. A mitochondria-enriched fraction exhibited cyanide-sensitive oxygen uptake in the presence of succinate. T. gondii mitochondria were solubilized and subjected to Blue Native Electrophoresis followed by second dimension electrophoresis. Selected protein spots from the 2D gels were subjected to mass spectrometry analysis and polypeptides of mitochondrial complexes III, IV and V were identified. Subunits COX2A and COX2B were detected immunochemically and found to co-migrate with complex IV; therefore, they are subunits of the parasite's cytochrome c oxidase. The apparent molecular mass of the T. gondii mature COX2A subunit differs from that of the chlorophycean alga Polytomella sp. The data suggest that during its biogenesis, the mitochondrial targeting sequence of the apicomplexan COX2A precursor protein may be processed differently than the one from its algal counterpart.

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Visualizing Nuclear Structure In Situ by Atomic Force Microscopy

Jiménez‐García

Segura-Valdéz

Atomic Force Microscopy

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Further Ultrastructural Characterization of the Intranuclear Ring-Shaped Bodies of the Plant Lacandonia schismatica

Cited by 3 publications

References 17 publications

Lacandonia granules are present in Ginkgo biloba cell nuclei

Lacandonia granules are present in Ginkgo biloba cell nuclei

The polypeptides COX2A and COX2B are essential components of the mitochondrial cytochrome c oxidase of Toxoplasma gondii

Visualizing Nuclear Structure In Situ by Atomic Force Microscopy

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