In Silico Survey and Characterization of Babesia microti Functional and Non-Functional Proteases

Human babesiosis caused by the intraerythrocytic apicomplexan Babesia microti is an expanding tick-borne zoonotic disease that may cause severe symptoms and death in elderly or immunocompromised individuals. In light of an increasing resistance of B. microti to drugs, there is a lack of therapeutic alternatives. Species-specific proteases are essential for parasite survival and possible chemotherapeutic targets. However, the repertoire of proteases in B. microti remains poorly investigated. Herein, we employed several combined bioinformatics tools and strategies to organize and identify genes encoding for the full repertoire of proteases in the B. microti genome. We identified 64 active proteases and 25 nonactive protease homologs. These proteases can be classified into cysteine (n = 28), serine (n = 21), threonine (n = 14), asparagine (n = 7), and metallopeptidases (n = 19), which, in turn, are assigned to a total of 38 peptidase families. Comparative studies between the repertoire of B. bovis and B. microti proteases revealed differences among sensu stricto and sensu lato Babesia parasites that reflect their distinct evolutionary history. Overall, this data may help direct future research towards our understanding of the biology and pathogenicity of Babesia parasites and to explore proteases as targets for developing novel therapeutic interventions.Instituto de PatobiologíaFil: Florin-Christensen, Monica. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; ArgentinaFil: Florin-Christensen, Monica. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wieser, Sarah Nathaly. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina.Fil: Wieser, Sarah Nathaly. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Suarez, Carlos E. USDA-ARS. Animal Disease Research Unit; Estados UnidosFil: Suarez, Carlos E. Washington State University. Department of Veterinary Microbiology and Pathology; Estados UnidosFil: Schnittger, Leonhard. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; ArgentinaFil: Schnittger, Leonhard. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

In silico identification of immunotherapeutic and diagnostic targets in the glycosylphosphatidylinositol metabolism of the coccidian Sarcocystis aucheniae

Meat of the South American camelids (SACs) llama and alpaca is an important source of animal protein and income for rural families in the Andes, and a product with significant growth potential for local and international markets. However, infestation with macroscopic cysts of the coccidian protozoon Sarcocystis aucheniae, a parasitosis known as SAC sarcocystosis, significantly hampers its commercialization. There are no validated methods to diagnose the presence of S. aucheniae cysts other than carcass examination. Moreover, there are no available drugs or vaccines to cure or prevent SAC sarcocystosis. Identification of relevant molecules that act at the host–pathogen interface can significantly contribute to the control of this disease. It has been shown for other pathogenic protozoa that glycosylphosphatidylinositol (GPI) is a critical molecule implicated in parasite survival and pathogenicity. This study focused on the identification of the enzymes that participate in the S. aucheniae GPI biosynthetic pathway and the repertoire of the parasite GPI‐anchored proteins (GPI‐APs). To this aim, RNA was extracted from parasite cysts and the transcriptome was sequenced and translated into amino acid sequences. The generated database was mined using sequences of well‐characterized GPI biosynthetic enzymes of Saccharomyces cerevisiae and Toxoplasma gondii. Eleven enzymes predicted to participate in the S. aucheniae GPI biosynthetic pathway were identified. On the other hand, the database was searched for proteins carrying an N‐terminal signal peptide and a single C‐terminal transmembrane region containing a GPI anchor signal. Twenty‐four GPI‐anchored peptides were identified, of which nine are likely S. aucheniae‐specific, and 15 are homologous to membrane proteins of other coccidians. Among the latter, 13 belong to the SRS domain superfamily, an extensive group of coccidian GPI‐anchored proteins that mediate parasite interaction with their host. Phylogenetic analysis showed a great degree of intra‐ and inter‐specific divergence among SRS family proteins. In vitro and in vivo experiments are needed to validate S. aucheniae GPI biosynthetic enzymes and GPI‐APs as drug targets and/or as vaccine or diagnostic antigens.Instituto de PatobiologíaFil: Decker Franco, Cecilia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wieser, Sarah Nathaly. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; ArgentinaFil: Soria, Marcelo Abel. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; ArgentinaFil: De Alba Paloma. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; ArgentinaFil: Florin-Christensen, Monica. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schnittger, Leonhard. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Advancing human nutrition without degrading land resources through modeling cropping systems in the Ethiopian highlands

Food shortage in sub-Saharan Africa is generally considered a function of limited access to food, with little thought to nutritional quality. Analyzing household production of nutrients across farming systems could be valuable in guiding the improvement of those systems. An optimization model was employed to analyze the scenario of human nutrition and cropland allocation in enset (Enset ventricosum)/root crop-based and cereal-based systems of the Ethiopian Highlands. The type and amount of nutrients produced in each system were analyzed, and an optimization model was used to analyze which cropping strategies might improve the nutritional quality of the household using existing resources. Both production systems were in food deficit, in terms of quantity and quality of nutrients, except for iron. The energy supply of resource-poor households in the enset/root crop-based system was only 75% of the recommended daily dietary allowance (RDA) of the World Health Organization (WHO), whereas resource-rich farmers were able to meet their energy, protein, zinc, and thiamine demands. Extremely high deficiency was found in zinc, calcium, vitamin A, and vitamin C, which provided only 26.5%, 34%, 1.78%, and 12%, of the RDA, respectively. The RDA could be satisfied if the land area occupied by enset, kale, and beans were expanded by about 20%, 10%, and 40%, respectively, at the expense of maize and sweet potato. The cereal-based system also had critical nutrient deficits in calcium, vitamin A, and vitamin C, which provided 30%, 2.5%, and 2% of the RDA, respectively. In the cereal system, the RDA could be fully satisfied by reducing cropland allocated to barley by about 50% and expanding the land area occupied by faba beans, kale, and enset. A shift from the cereal/root crop-dominated system to a perennial-enset dominated system would decrease soil erosion by improving the crop factor by about 45%. This shift would also have a very strong positive impact on soil fertility management. However, any policy suggestions for change in cropland allocation should be done through negotiations with households, communities, and district stakeholders

Vaccination against babesiosis using recombinant GPI-anchored proteins

In Press, Corrected ProofThe increase in human babesiosis is of major concern to health authorities. In the USA, most of these cases are due to infections with Babesia microti, whereas in Europe B. divergens is the major cause of clinical disease in humans. Here we review the immunological and biological literature of glycosylphosphatidylinositol (GPI)-anchored merozoite proteins of human Babesia parasites with emphasis on their role in immunity, and provide some new bioinformatical information on B. microti GPI-Anchored Proteins (GPI-AP). Cattle can be vaccinated with soluble parasite antigens (SPA) of Babesia divergens that are released by the parasite during proliferation. The major component in SPA preparations appeared to be a 37 kDa merozoite surface protein that is anchored in the merozoite membrane by a GPI anchor. Animals could be protected by vaccination with the recombinant 37 kDa protein expressed in Escherichia coli, provided the protein had a hydrophobic terminal sequence. Based on this knowledge, a recombinant vaccine was developed against Babesia canis infection in dogs, successfully. In order to identify similar GPI-AP in B. microti, the genome was analysed. Here it is shown that B. microti encodes all proteins necessary for GPI assembly and its subsequent protein transfer. In addition, in total 21 genes encoding for GPI-AP were detected, some of which reacted particularly strongly with sera from B. microti-infected human patients. Reactivity of antibodies with GPI-anchored merozoite proteins appears to be dependent on the structural conformation of the molecule. It is suggested that the three-dimensional structure of the protein that is anchored in the membrane is different from that of the protein that has been shed from the merozoite surface. The significance of this protein’s dynamics in parasite biology and immune evasion is discussed. Finally, we discuss developments in tick and Babesia vaccine research, and the role such vaccines could play in the control of human babesiosis.Instituto de PatobiologíaFil: Wieser, Sarah Nathaly. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schnittger, Leonhard. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Florin-Christensen, Monica. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Delbecq, Stephane. Université de Montpellier.· Vaccination Antiparasitaire; FranciaFil: Schetters, Theo. Université de Montpellier.· Vaccination Antiparasitaire; Francia. University of Pretoria. Veterinary Faculty. Department of Veterinary Tropical Diseases; Sudáfric