Abstract

Cytogenetic and protein quantification in polyploid somatic tissue of Myrmeleon uniformis (Neuroptera, Myrmeleontidae)

Myrmeleon unifomis Malpighian tubules cells were analyzed under two aspects: chromatin structure and total protein quantification in the three larval phases (L1, L2 and L3) and in adults. This insect Malpighian tubules present polyploid tissue resultant from endoreduplication, which probably begins in the first larval phases. The Malpighian tubule proximal region in L2, L3 and adult cells has polyploid nuclei, although the polyploid degree does not cause change in its morphology; nevertheless in the L3 larvae distal region, polyploidization changes the cell morphology from a round to a multilobulate shape. Chromatin analysis in these nuclei by cytochemical techniques showed that the whole nucleus is filled out with a granular chromatin. In multilobulate nuclei during L3 the chromatin is formed by a network of chromatin fibers. The nucleolar markings made in the several development phases of Myrmeleon sp showed the gradual increase that occurs during the larval phases and their reduction in the adult phase. This transcriptional activity was confirmed by total protein analyses, which were quantified by SDS-PAGE. The 39.8-kDa band deserves prominence, because it can be seen from L2 phase, increasing its intensity during L3 and decreasing in the adult phase, indicating that this protein is related to production of the pupation cocoon.

• PDF