Fatty Acid Composition and Metabolism in Leishmania Parasite Species: Potential Biomarkers or Drug Targets for Leishmaniasis?

Exploring the use of fatty acid ethyl esters as a potential natural solution for the treatment of fish parasitic diseases

Alternatives to conventional chemical treatments for parasitic diseases in fish are needed. Microalgal-sourced fatty acid ethyl esters (FAEEs) have shown an antiparasitic effect against Gyrodactylus turnbulli infection in guppies. Here, we tested a range of commercial FAEEs of various carbon chain lengths and unsaturation levels against two fish parasites. Guppies and barramundi infected with G. turnbulli and Trichodina sp., respectively, were used. The most effective FAEE, after excluding those toxic to fish, was ethyl laurate (12:0). For both parasites, the LD50 was 18.75 μM within 250 min of incubation. Ethyl eicosapentaenoate (20:5n3) was the next most effective FAEE against G. turnbulli, and dihomo-γ-linolenic acid ethyl ester (20:3n6) and ethyl α-linolenate (18:3n3) were the next most effective against Trichodina sp. In addition, FAEEs prepared from the microalga Phaeodactylum tricornutum residue, after fucoxanthin extraction, were examined against Trichodina sp. infection in barramundi for the first time. LD85 and LD100 was achieved at 2.5 and 5 μL mL-1 of the FAEE preparation, respectively. In vivo, immersion of infected barramundi in 1.25 μL mL-1 of this preparation for 24 h reduced infection prevalence from 100% to 53% and was non-toxic to fish.

In silico prediction of the metabolism of Blastocrithidia nonstop, a trypanosomatid with non-canonical genetic code

BACKGROUND

Almost all extant organisms use the same, so-called canonical, genetic code with departures from it being very rare. Even more exceptional are the instances when a eukaryote with non-canonical code can be easily cultivated and has its whole genome and transcriptome sequenced. This is the case of Blastocrithidia nonstop, a trypanosomatid flagellate that reassigned all three stop codons to encode amino acids.

RESULTS

We in silico predicted the metabolism of B. nonstop and compared it with that of the well-studied human parasites Trypanosoma brucei and Leishmania major. The mapped mitochondrial, glycosomal and cytosolic metabolism contains all typical features of these diverse and important parasites. We also provided experimental validation for some of the predicted observations, concerning, specifically presence of glycosomes, cellular respiration, and assembly of the respiratory complexes.

CONCLUSIONS

In an unusual comparison of metabolism between a parasitic protist with a massively altered genetic code and its close relatives that rely on a canonical code we showed that the dramatic differences on the level of nucleic acids do not seem to be reflected in the metabolisms. Moreover, although the genome of B. nonstop is extremely AT-rich, we could not find any alterations of its pyrimidine synthesis pathway when compared to other trypanosomatids. Hence, we conclude that the dramatic alteration of the genetic code of B. nonstop has no significant repercussions on the metabolism of this flagellate.

Molecular Research on Vector-Borne Diseases of Medical Interest: From Bench to Application 2.0

Infectious diseases caused by parasites (malaria, leishmaniasis, trypanosomiasis, filariasis…), viruses (chikungunya, dengue, phlebovirus, etc [...].