Heme modulates Trypanosoma cruzi bioenergetics inducing mitochondrial ROS production.

Trypanosoma cruzi is the causative agent of Chagas disease and has a single mitochondrion, an organelle responsible for ATP production and the main site for the formation of reactive oxygen species (ROS). T. cruzi is an obligate intracellular parasite with a complex life cycle that alternates between vertebrate and invertebrate hosts, therefore the development of survival strategies and morphogenetic adaptations to deal with the various environments is mandatory. Over the years our group has been studying the vector-parasite interactions using heme as a physiological oxidant molecule that triggered epimastigote proliferation however, the source of ROS induced by heme remained unknown. In the present study we demonstrate the involvement of heme in the parasite mitochondrial metabolism, decreasing oxygen consumption leading to increased mitochondrial ROS and membrane potential. First, we incubated epimastigotes with carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP), an uncoupler of oxidative phosphorylation, which led to decreased ROS formation and parasite proliferation, even in the presence of heme, correlating mitochondrial ROS and T. cruzi survival. This hypothesis was confirmed after the mitochondria-targeted antioxidant ((2-(2,2,6,6 Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride (MitoTEMPO) decreased both heme-induced ROS and epimastigote proliferation. Furthermore, heme increased the percentage of tetramethylrhodamine methyl ester (TMRM) positive parasites tremendously-indicating the hyperpolarization and increase of potential of the mitochondrial membrane (ΔΨm). Assessing the mitochondrial functional metabolism, we observed that in comparison to untreated parasites, heme-treated epimastigotes decreased their oxygen consumption, and increased the complex II-III activity. These changes allowed the electron flow into the electron transport system, even though the complex IV (cytochrome c oxidase) activity decreased significantly, showing that heme-induced mitochondrial ROS appears to be a consequence of the enhanced mitochondrial physiological modulation. Finally, the parasites that were submitted to high concentrations of heme presented no alterations in the ultrastructure. Consequently, our results suggest that heme released by the insect vector after the blood meal, modify epimastigote mitochondrial physiology to increase ROS as a metabolic mechanism to maintain epimastigote survival and proliferation.

Trichuris trichiura in a post-Colonial Brazilian mummy.

Trichuris trichiura is a soil-transmitted helminth which is prevalent in warm, moist, tropical and subtropical regions of the world with poor sanitation. Heavy whipworm can result either in Trichuris dysenteric syndrome - especially in children - or in a chronic colitis. In heavy infections, worms can spread proximally and may cause ileitis. Here we provide first microscopic evidence for a T. trichiura adult worm embedded in the rectum of a post-Colonial Brazilian adult mummy. During Colonial and post-Colonial times, many European chroniclers described a parasitic disease named Maculo whose symptomatology coincides with heavy helminthiasis. Based on our findings and on comparison of ancient textual evidence with modern description of heavy whipworm, we feel confident in considering that the two syndromes are expressions of the same pathological condition.

Trichuris trichiura in a post-Colonial Brazilian mummy

Trichuris trichiura is a soil-transmitted helminth which is prevalent in warm, moist, tropical and subtropical regions of the world with poor sanitation. Heavy whipworm can result either in Trichuris dysenteric syndrome - especially in children - or in a chronic colitis. In heavy infections, worms can spread proximally and may cause ileitis. Here we provide first microscopic evidence for a T. trichiura adult worm embedded in the rectum of a post-Colonial Brazilian adult mummy. During Colonial and post-Colonial times, many European chroniclers described a parasitic disease named Maculo whose symptomatology coincides with heavy helminthiasis. Based on our findings and on comparison of ancient textual evidence with modern description of heavy whipworm, we feel confident in considering that the two syndromes are expressions of the same pathological condition.

A new species of Trichuris from Thrichomys apereoides (Rodentia: Echimyidae) in Brazil: Morphological and histological studies.

Trichuris thrichomysi n. sp., recovered from the cecum of the wild rodent Thrichomys apereoides from a transition zone between the Atlantic Forest and Cerrado morfoclimatic domains, and its life cycle observed under experimental conditions are described. This new species is closely related to Trichuris travassosi, Trichuris chiliensis and Trichuris fulvi, but can be distinguished from them mainly by differences in the posterior end of males. Details of the surface such as the bacillary gland, cuticular inflations and several morphological details obtained by scanning electron microscopy and field emission scanning electron microscopy confirmed the characteristics that differentiate the new species. The histopathology of the intestinal wall of naturally infected rodents is also reported. The present study extends the geographical distribution of T. thrichomysi n. sp to the Pantanal ecosystem and reports a new host, Thrichomys pachiurus.

First report of Angiostrongylus cantonensis (Nematoda: Metastrongylidae) in Achatina fulica (Mollusca: Gastropoda) from Southeast and South Brazil.

The rat lungworm Angiostrongylus cantonensis is a worldwide-distributed zoonotic nematode that can cause human eosinophilic meningoencephalitis. Here, for the first time, we report the isolation of A. cantonensis from Achatina fulica from two Brazilian states: Rio de Janeiro (specifically the municipalities of Barra do Piraí, situated at the Paraiba River Valley region and São Gonçalo, situated at the edge of Guanabara Bay) and Santa Catarina (in municipality of Joinville). The lungworms were identified by comparing morphological and morphometrical data obtained from adult worms to values obtained from experimental infections of A. cantonensis from Pernambuco, Brazil, and Akita, Japan. Only a few minor morphological differences that were determined to represent intra-specific variation were observed. This report of A. cantonensis in South and Southeast Brazil, together with the recent report of the zoonosis and parasite-infected molluscs in Northeast Brazil, provide evidence of the wide distribution of A. cantonensis in the country. The need for efforts to better understand the role of A. fulica in the transmission of meningoencephalitis in Brazil and the surveillance of molluscs and rodents, particularly in ports, is emphasized.

First report of Angiostrongylus cantonensis (Nematoda: Metastrongylidae) in Achatina fulica (Mollusca: Gastropoda) from Southeast and South Brazil

The rat lungworm Angiostrongylus cantonensis is a worldwide-distributed zoonotic nematode that can cause human eosinophilic meningoencephalitis. Here, for the first time, we report the isolation of A. cantonensis from Achatina fulica from two Brazilian states: Rio de Janeiro (specifically the municipalities of Barra do Piraí, situated at the Paraiba River Valley region and São Gonçalo, situated at the edge of Guanabara Bay) and Santa Catarina (in municipality of Joinville). The lungworms were identified by comparing morphological and morphometrical data obtained from adult worms to values obtained from experimental infections of A. cantonensis from Pernambuco, Brazil, and Akita, Japan. Only a few minor morphological differences that were determined to represent intra-specific variation were observed. This report of A. cantonensis in South and Southeast Brazil, together with the recent report of the zoonosis and parasite-infected molluscs in Northeast Brazil, provide evidence of the wide distribution of A. cantonensis in the country. The need for efforts to better understand the role of A. fulica in the transmission of meningoencephalitis in Brazil and the surveillance of molluscs and rodents, particularly in ports, is emphasized.