Detection of NADPH-diaphorase activity in Paramecium primaurelia

Andrea Amaroli, Marzia Ognibene, Francesca Trielli, Sonya Trombino, Carla Falugi, Maria Umberta Delmonte Corrado

Research output: Contribution to journalArticlepeer-review


Recently, we showed that Paramecium primaurelia synthesizes molecules functionally related to the cholinergic system and involved in modulating cell-cell interactions leading to the sexual process of conjugation. It is known that nitric oxide (NO) plays a role in regulating the release of transmitter molecules, such as acetylcholine, and that the NO biosynthetic enzyme, nitric oxide synthase (NOS), shows nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity. In this work, we detected the presence of NADPH-d activity in P. primaurelia. We characterized this activity histochemically by examining its specificity for β-NADPH and α-NADH co-substrates, and sensitivity both to variations in chemico-physical parameters and to inhibitors of enzymes showing NADPH-d activity. Molecules immunologically related to NOS were recognized by the anti-rat brain NOS (bNOS) antibody. Moreover, bNOS immunoreactivity and NADPH-d activity sites were found to be co-localized. The non-denaturing electrophoresis, followed by exposure to β-NADPH or α-NADH co-substrates, revealed the presence of a band of apparent molecular mass of about 124 kDa or a band of apparent molecular mass of about 175 kDa, respectively. In immunoblot experiments, the bNOS antibody recognized a single band of apparent molecular mass of about 123 kDa.

Original languageEnglish
Pages (from-to)201-208
Number of pages8
JournalEuropean Journal of Protistology
Issue number3
Publication statusPublished - Sep 29 2006


  • Ciliates
  • NADPH-diaphorase activity
  • Nitric oxide synthase immunoreactivity
  • Paramecium

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Microbiology


Dive into the research topics of 'Detection of NADPH-diaphorase activity in Paramecium primaurelia'. Together they form a unique fingerprint.

Cite this