Phylogenetic and morphological characterization of trypanosomes from Brazilian armoured catfishes and leeches reveal high species diversity, mixed infections and a new fish trypanosome species.

BACKGROUND: Several Trypanosoma species transmitted by leeches infect marine and freshwater fish worldwide. To date, all South American fish trypanosome species identified have been based on unreliable morphological parameters. We recently isolated and cultured trypanosomes from the Brazilian armoured catfishes Hypostomus luetkeni and H. affinis. Here, we report the first phylogenetic analyses of South American (Brazilian) trypanosomes isolated from fish, and from leeches removed from these fish. We also analysed morphologically and morphometrically the different forms of fish, leech and cultured trypanosomes. METHODS: V7V8 SSU rRNA and gGAPDH sequences were used for phylogenetic analysis of Brazilian fish and leech trypanosomes. Trypanosomes from cultures, fish blood and leech samples were also characterized morphologically and morphometrically by light and electron microscopy. RESULTS: In blood smears from fish high trypanosome prevalence (90-100 %) and parasitemia (0.9-1.0x10(2)) were observed. Phylogenetic relationships using SSU rRNA and gGAPDH showed that, despite relevant sequence divergence, all Brazilian fish (and derived cultures) and leech trypanosomes clustered together into a single clade. The Brazilian clade clustered with European, North American and African fish trypanosomes. Based on sequence analysis, we uncovered a new species of Brazilian fish trypanosome, Trypanosoma abeli n. sp. Trypanosoma abeli cultures contained pleomorphic epimastigotes, small trypomastigotes and rare sphaeromastigotes. Ultrastructural features of T. abeli included a cytostome-cytopharynx complex in epi- and trypomastigotes, a compact rod-like kinetoplast, lysosome-related organelles (LROs) and multivesicular bodies. Trypanosomes found in fish blood smears and leech samples were highly pleomorphic, in agreement with sequence data suggesting that catfishes and leeches often have mixed trypanosome infections. CONCLUSIONS: Trypanosoma abeli n. sp. is the first trypanosome from South American fishes isolated in culture, positioned in phylogenetic trees and characterized at the ultrastructural level. Trypanosoma abeli n. sp. is highly prevalent in H. luetkeni and H. affinis armoured catfish from the Atlantic Forest biome, and in other catfish species from the Amazon and the Pantanal. Sequencing data suggested that Brazilian catfish often have mixed trypanosome infections, highlighting the importance of molecular characterization to identify trypanosome species in fishes and leeches.

Microalgae for economic applications: advantages and perspectives for bioethanol.

Renewable energy has attracted significant interest in recent years as a result of sustainability, environmental impact, and socio-economic considerations. Given existing technological knowledge and based on projections relating to biofuels derived from microalgae, microalgal feedstock is considered to be one of the most important renewable energy sources potentially available for industrial production. Therefore, this review examines microalgal bioethanol technology, which converts biomass from microalgae to fuel, the chemical processes involved, and possible ways of increasing the bioethanol yield, such as abiotic factors and genetic manipulation of fermenting organisms.

Efficacy of miltefosine treatment in Leishmania amazonensis-infected BALB/c mice.

Leishmaniasis is one of the most serious worldwide diseases caused by protozoan parasites of the Leishmania genus, affecting millions of people around the world. All currently available treatments present severe toxic side effects, require long-term compliance, cause serious side effects and are uncomfortable for patients. Leishmania amazonensis, a species endemic to Brazil, causes severe localised or diffuse skin lesions in humans. Owing to the unsatisfactory nature of the currently available chemotherapies, new approaches have been assessed for improved therapeutic intervention strategies against leishmaniasis. Miltefosine is an alkylphospholipid analogue that exhibits potent activity against the different clinical manifestations of leishmaniasis. Thus, the aim of this study was to investigate the long-term efficacy of miltefosine in BALB/c mice infected with L. amazonensis owing to the lack of a profound study demonstrating its dose-dependent and long-term effects. It was observed that animals treated with 20-50 mg/kg/day of miltefosine exhibited a significant dose-dependent reduction in lesion size; furthermore, in mice receiving higher doses, lesions disappeared after the end of treatment. To confirm a possible parasitological cure, mice up to 250 days after the end of treatment were analysed. No lesions or presence of parasite DNA were found in mice treated with 30, 40 and 50 mg/kg/day of miltefosine. In summary, these results show that miltefosine may be used to treat cutaneous leishmaniasis caused by L. amazonensis, alone or as combination therapy.