Claudio Ortenzi

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The second of two diffusible cell signal proteins (pheromones) purified from a wild-type strain of the Antarctic ciliate, Euplotes nobilii, has been determined by automated Edman degradation of the whole molecule and peptides generated by its chymotryptic digestion. The proposed sequence of 52 amino acids of this new pheromone, designated En-1, is:(More)
Genes encoding the enzyme methionine sulfoxide reductase type B, specific to the reduction of the oxidized methionine-R form, were characterized from the expressed (macronuclear) genome of two ecologically separate marine species of Euplotes, i.e. temperate water E. raikovi and polar water E. nobilii. Both species were found to contain a single msrB gene(More)
Free-living species of ciliated Protozoa control their vegetative (mitotic) proliferation and mating (sexual) processes by diffusible, cell type-specific protein signals (pheromones). One of these molecules, designated En-2, was isolated from a species, Euplotes nobilii, living in the stably cold marine waters of Antarctica, and its complete amino acid(More)
Coleps hirtus is a small common freshwater ciliate belonging to the protostomatid group, its body covered by calcified plates assembled to form an armor. Coleps feeds on bacteria, algae, flagellates, living and dead ciliates, animal and plant tissues. To assist its carnivorous feeding the ciliate is equipped with offensive extrusomes (toxicysts), clustering(More)
The time-honored assumption about the defensive function of trichocysts in Paramecium against predators was recently verified experimentally against different species of unicellular predators. In the present study, we examined the defensive function of trichocysts against three metazoan predators, Cephalodella sp. (Rotifera), Eucypris sp. (Arthropoda), and(More)
The determination of a number of pheromone structures from species of Euplotes provided direct evidence that these cell typespecific signals are represented by families of homologous proteins, consistently with their genetic control through series of single-locus multiple alleles. Due to their structural homology, unequivocally manifested by the(More)
Climacostol, a compound produced by the ciliated protozoan Climacostomum virens, displayed cytotoxic properties in vitro. This study demonstrates that it has anti-tumour potential. Climacostol caused a reduction of viability/proliferation of B16-F10 mouse melanoma cells, a rapidly occurring DNA damage, and induced the intrinsic apoptotic pathway(More)
Several modern drugs, including those for cancer therapy, have been isolated from natural sources, are based on natural products and its derivatives, or mime natural products. Some of them are in clinical use, others in clinical trials. The success of natural products in drug discovery is related to their biochemical characteristics and to the technologic(More)
Climacostol (5-(Z)-non-2-enyl-benzene-1,3-diol) is a natural toxin isolated from the freshwater ciliated protozoan Climacostomum virens and belongs to the group of resorcinolic lipids, compounds that show antimicrobial, antiparasitic and antitumor activities. We investigated the cytotoxic activity of the chemically synthesized toxin on: (1) human tumor(More)