[
Exp Parasitol,
1958]
The rate of discovery of new anthelmintics has increased but little during the past two decades. The same interval has been characterized by accelerated progress in chemotherapy, and especially by the appearance of various and diverse antibiotics discovered with in vitro screening tests. Lamson and Brown (1936) stated that both in vitro and in vivo anthelmintic tests aid in determining the probable action of chemicals in the host. Subsequently, in vivo tests have been increasingly emphasized by helminthologists, even for the initial evaluation of untried substances. Steward discussed screening methods, and described a preliminary test using rats doubly infected with intestinal and caecal nematodes. Choices of methods by various investigators have been influenced by an assumption that the antinematode activity of phenothiazine is detectable only in vivo, but this assumption is no longer entirely tenable. Anthelmintic tests should be sensitive enough to permit recognition of inhibitors of single vital enzymes. An ideal test would require only minute quantities of chemicals for titration against representative species and stages of the more economically important parasites. The present paper describes a procedure that begins to meet these requirements. It consumes less than 10 mg of each substance, and one operator can process about 100 samples per month. Phenothiazine serves as a standard of reference if developing trichostrongyle nematodes are utilized as test organisms. That chemical is characterized by a general ineffectiveness against members of the nematode subfamily Rhabditinae, together with a high toxicity for embryos and
Relini A, Tortora P, Gatta E, De Gioia L, Airoldi C, Natalello A, Vertemara J, Visentin C, Penco A, Pellistri F, Regonesi ME, Bonanomi M
[
Hum Mol Genet,
2017]
The protein ataxin-3 (ATX3) triggers an amyloid-related neurodegenerative disease when its polyglutamine stretch is expanded beyond a critical threshold. We formerly demonstrated that the polyphenol epigallocatechin-3-gallate (EGCG) could redirect amyloid aggregation of a full-length, expanded ATX3 (ATX3-Q55) towards non-toxic, soluble, SDS-resistant aggregates. Here, we have characterized other related phenol compounds, although smaller in size, i.e., (-)-epigallocatechin gallate (EGC), and gallic acid (GA). We analyzed the aggregation pattern of ATX3-Q55 and of the N-terminal globular Josephin domain (JD) by assessing the time course of the soluble protein, as well its structural features by FTIR and AFM, in the presence and the absence of the mentioned compounds. All of them redirected the aggregation pattern towards soluble, SDS-resistant aggregates. They also prevented the appearance of ordered side-chain hydrogen bonding in ATX3-Q55, which is the hallmark of polyQ-related amyloids. Molecular docking analyses on the JD highlighted three interacting regions, including the central, aggregation-prone one. All three compounds bound to each of them, although with different patterns. This might account for their capability to prevent amyloidogenesis. Saturation transfer difference NMR experiments also confirmed EGCG and EGC binding to monomeric JD. ATX3-Q55 pre-incubation with any of the three compound prevented its calcium-influx-mediated cytotoxicity towards neural cells. Finally, all the phenols significantly reduced toxicity in a transgenic Caenorhabditis elegans strain expressing an expanded ATX3. Overall, our results show that the three polyphenols act in a substantially similar manner. GA, however, might be more suitable for antiamyloid treatments due to its simpler structure and higher chemical stability.