Localization, specific activity, and molecular forms of acetylcholinesterase in developmental stages of the cestode Mesocestoides corti

Abstract

The nervous system of flatworms is quite simple although there is increasing evidence indicating that it is chemically complex. Studies of the nervous system in these animals have only been performed in the larval stage or in the adult worms, which are easy to obtain in nature, while the description of the nervous system in developing stages of these organisms is missing. Mesocestoides corti is a parasitic platyhelminth whose larvae can be induced in vitro to develop to adult, sexually mature worms, opening the possibility of studying the nervous system of a flatworm in different stages of development. Here, we describe the presence, activity, location, and molecular forms of acetylcholinesterase (AChE) in different stages of development of M. corti, from the larvae to adult forms of this endoparasite, obtained in in vitro cultures after induction of the larval stage with trypsin. Our results point to AChE as a molecular marker of the nervous system in platyhelminthes. The change in molecular forms of this enzyme and the increase in its activity during development from larvae to adult worm may reflect the presence of a more complex nervous system, necessary to adjust and coordinate the movement of a much bigger structure. A relationship between the development of the reproductive apparatus in segmented and adult worms with a more complex nervous system in these stages is also apparent. Finally, our study opens the possibility of applying anti-AChE as more effective therapeutic strategies against cestode parasites.

Taenia larvae possess distinct acetylcholinesterase profiles with implications for host cholinergic signalling

“…Once the genome for T. crassiceps has been sequenced, future work will also be able to determine potential differences in AChE amino-acid sequences between cestode species. Notably, the reported AChE activity of tetrathyridia of Mesocestoides corti, another popular model parasite for neurocysticercosis research, is far greater than that which we report for both T. crassiceps and T. solium [54]. These differences should be considered when selecting an appropriate model parasite for NCC research.…”

Developmental expression pattern of histone H4 gene associated to DNA synthesis in the endoparasitic platyhelminth Mesocestoides corti

“…We have previously shown that a 24 h treatment with trypsin and FBS, followed by an incubation in FBS alone, induced development of M. corti tetrathyridia to adult worm (Markoski et al, 2003;Espinoza et al, 2005;Kemmerling et al, 2006). Here we extend this description following different steps in the elongation and segmentation events by scanning electron microscopy.…”

“…At different stages of development of M. corti, from larvae to adult forms, proliferative cells were concentrated along the nerve cords. This regionalization of proliferative cells is consistent with a longitudinal growth of the parasite which is in turn coordinated with the development of a more complex nervous system, probably designed to support the movements of the proglotids in the segmented and in the adult worms attached to the intestine of the host (Kemmerling et al, 2006).…”

Functional Imaging of Neurotransmitters in Hymenolepis diminuta Treated with Senna Plant Through Light and Confocal Microscopy

“…The AChE expression was observed using ATCI as the substrate following the staining protocol of Kemmerling et al (2006) with some modifications. In brief the control and treated parasites were incubated in 20 mL of staining medium (ATCI-2.2 mg/mL added to a solution of 0.1 M acetate buffer at pH-6.3, 0.1 M sodium citrate, 5 mM potassium ferricyanide, and 30 mM copper sulfate) for ~2 h. However, time taken for staining (Hatchett’s brown) varies from scolex to proglottids.…”