Atomic force microscopy imaging of thin sections of lacandonia granules

Lacandonia schismatica. Martínez and Ramos (Lacandoniaceae: Triuridales) is an endemic and rare plant species, with the sex organs spatially inverted. Interestingly, within the cell nucleus, the chromatin is reticulated and it is associated a novel structure named Lacandonia granules, a very abundant ribonucleoprotein particle showing similarities with perichromatin and Balbiani ring granules present in cells of mammals and insects, respectively. It is suggested that both structures participate in the metabolism of the RNA, in phenomena of transport and/or storage of RNA messenger (mRNA). Although these particles have been observed in several groups of plants as Ginkgo biloba. Kaempfer (Ginkgoaceae: Ginkgoales), their fine structure has not been observed with sufficient resolution. Previous studies demonstrate that the cellular and nuclear structure of Lacandonia schismatica is susceptible of being analyzed with atomic force microscopy (AFM). The goal of this work is to visualize and to analyze the nanometric structure and organization of the granules of Lacandonia in situ by AFM, using techniques of preparation typical for biological material for transmission electron microscopy (TEM). Using AFM in the contact mode, it was possible to observe some granular structures inside the interchromatin space and in the periphery of the perichromatin space that corresponds to the granules of Lacandonia. They are irregular in shape, depending on the activity state, some of them are observed with spherical shape, besides observing the great variety of ribonucleoproteins molecules that are in the area mentioned previously. In the tapping mode, the granules are appreciated in certain depth with more definition, until being able to observe a heap of these structures as they have been observed by TEM, but with higher vertical resolution than that obtained horizontally by TEM, which allows determining three-dimensional images for the observation of fine details of the structure. Copyright © 2009 American Scientific Publishers All rights reserved.