QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Corrado, M. U. D. Articles by Falugi, C. Search for Related Content PubMed PubMed Citation Articles by Corrado, M. U. D. Articles by Falugi, C. Social Bookmarking                         What's this?

The Journal of Experimental Biology 204, 1901-1907 (2001)
© 2001 The Company of Biologists Limited

Synthesis of the Signal Molecule Acetylcholine during the Developmental Cycle of PARAMECIUM PRIMAURELIA (Protista, Ciliophora) and its Possible Function in Conjugation

Maria Umberta Delmonte Corrado^1,*, Huguette Politi¹, Marzia Ognibene¹, Cristiano Angelini², Francesca Trielli¹, Patrizia Ballarini³ and Carla Falugi²

¹ Department for the Study of the Territory and its Resources, University of Genoa, Corso Europa 26, I-16132 Genoa, Italy,
² Department of Experimental, Environmental, and Applied Biology, University of Genoa, Viale Benedetto XV 5, I-16132 Genoa, Italy and
³ Department of Molecular, Cellular, and Animal Biology, University of Camerino, Via Camerini 2, I-62032 Camerino, Italy

*e-mail: corrado{at}dipteris.unige.it

Accepted March 9, 2001

We recently discovered, in mating-competent Paramecium primaurelia, the presence of functionally related molecules of the cholinergic system: the neurotransmitter acetylcholine (ACh), both its nicotinic and muscarinic receptors and its lytic enzyme acetylcholinesterase (AChE). Our results on the inhibition of mating-cell pairing in vivo in mating-competent cells treated with cholinomimetic drugs support the hypothesis that the cholinergic system plays a role in cell-to-cell adhesion. To investigate the possible function of the signal molecule ACh in conjugation in P. primaurelia, we attempted to detect the intracellular sites of ACh synthesis by localizing the ACh biosynthetic enzyme choline acetyltransferase (ChAT). Using immunocytochemical and histochemical methods, we have demonstrated the presence and activity of ChAT principally on the surface membrane of mating-competent cells and of mature but non-mating-competent cells. No evidence for ChAT activity was found in immature cells. Immunoblot analysis revealed the presence of immunoreactive bands, ranging in molecular mass from 42 to 133kDa, as reported for ChAT isolated from higher organisms. In vivo experiments showed that inhibition of ChAT activity by Congo Red, known to be a potent competitive inhibitor of acetyl coenzyme A, did not affect mating-cell pairing. Conversely, inhibition of AChE with BW284c51 or eserine, which block enzyme activity by reacting with a specific serine within the catalytic centre, significantly inhibited mating-cell pairing. Our results suggest that ACh has a negative modulating effect on conjugation in P. primaurelia.

Key words: acetylcholine, choline acetyltransferase, mating type, cell-to-cell adhesion, conjugation, Paramecium primaurelia, Protista

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				N. Santangelo and A. H Bass New insights into neuropeptide modulation of aggression: field studies of arginine vasotocin in a territorial tropical damselfish Proc R Soc B, December 22, 2006; 273(1605): 3085 - 3092. [Abstract] [Full Text] [PDF]

				J. Wiejak, L. Surmacz, and E. Wyroba Dynamin-association with agonist-mediated sequestration of beta-adrenergic receptor in single-cell eukaryote Paramecium J. Exp. Biol., April 15, 2004; 207(10): 1625 - 1632. [Abstract] [Full Text] [PDF]