Distribución de los ácidos nucleicos de los trofozoitos de Giardia lamblia durante la división nuclear

The changes of the nucleic acids distribution of Giardia lamblia trophozoites during nuclear division are described. The acridine-orange stained nuclei of live and fixed G. lamblia parasite showed green DNA and orange RNA fluorescence, and the nucleic acid nature was confirmed by DNase and RNase treatment. The RNA of both nuclei was organized in two forms: as an "eyebrows" and central oval corpuscles. These forms of RNA were fragmented in several condensations during nuclear division and distributed in the two new nuclei. The RNA in interphase did not disappear during mitosis. The DNA of both nuclei began to condense in several spherical bodies during prophase stage. In metaphase, was fully condensed as chromosomes-like structures. In early anaphase, the chromosome-like structures were very small and began to separate. In late anaphase, the chromosome-like structures were polarized. In telophase, the nuclei were elongated and the DNA began to decondense. Similar to other protozoa, karyokinesis was observed just before cytokinesis. In conclusion, the RNA of G. lamblia is fragmented during nuclear division and distributed in the two new daughter nuclei. The DNA undergoes different degrees of condensation, from decondensed chromatin to chromosome-like structures and we were able to observe structures similar to chromosomes in the metaphase.