Voltage gradients and microtubules both involved in intercellular protein and mitochondria transport in the telotrophic ovariole of Dysdercus intermedius

Abstract

In the telotrophic ovariole of Dysdercus intermedius the intercellular transport consists of different subsystems. Microinjection of FITC-labeled slowly diffusing proteins with opposite electrical net charges and of mitochondria was used to study the translocation of macromolecules and organelles. a) By intracellular measurements a voltage gradient of about 4 mV between the tropharium as the more negative side and the previtellogenic oocytes could be demonstrated. b) After injection into the tropharium negatively charged proteins migrated according to the electropotential gradient via the trophic cords into the oocytes. Positively charged proteins, however, were retained in the tropharium. c) After injection into previtellogenic oocytes both negatively and positively charged proteins moved into the trophic cords. Thus, the effectiveness of the electropotential gradient on the distribution of charged proteins is more pronounced from the tropharium side. d) Mitochondria microinjected into the trophic core were probably aligned along microtubules and translocated towards the trophic cords. - These results suggest that in the telotrophic bug ovariole a number of intercellular transport subsystems contribute to provide previtellogenic oocytes with nurse cells products. An electrophoretic transport mechanism for soluble proteins acting especially within the tropharium and a microtubule-associated transport for mitochondria could be evidenced.

Electrically mediated protein movement inDrosophila follicles

“…Fluorescently labeled proteins were able to cross the intercellular bridges in one way only, dependent upon their ionic charge. Similar results have been reported for Rhodniusprolixus (Huebner et al 1980;Telfer et al 1981), Oncopeltusfasciatus (Woodruff and Anderson 1984), and Dysdercus intermedius (Munz and Dittmann 1988). In each of these insects intracellular electrodes revealed intercellular voltage gradients that correlated with the movement of the charged molecules.…”

Ovary of Matsucoccus pini (Insecta, Hemiptera, Coccinea: Matsucoccidae): Morphology, ultrastructure, and phylogenetic implications

“…The trophocytes are also characterized by a high polarity that is manifested by the presence of long projections of the nuclear envelope directed toward the trophic core. The latter character as well as the occurrence of numerous microtubules in processes of trophocytes, in the trophic core, and in nutritive cords are associated with transport of macromolecules and organelles into the oocytes in the vitellarium (Gutzeit, ; Michalik et al, ; Münz and Dittmann, ; Szklarzewicz and Biliński, ; Szklarzewicz et al, ). Ultrastructural observations have also revealed that in the trophocyte cytoplasm of M. pini numerous rod‐shaped bacteria occur.…”