| Grant number: | 23/07336-6 |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| Start date: | February 01, 2024 |
| End date: | January 31, 2027 |
| Field of knowledge: | Agronomical Sciences - Veterinary Medicine |
| Principal Investigator: | Marta Maria Geraldes Teixeira |
| Grantee: | Letícia Pereira Úngari |
| Host Institution: | Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
Abstract The diversity of hemoparasites in fishes and is vast, with trypanosomes and hemogregarines representing the most widespread in different geographic regions of the world. Leeches transmit trypanosomes and hemogregarines to these hosts, but there are few studies on these vectors, that are restricted to a few hosts and/or localities. In addition, studies on phylogeography and phylogenetic relationships, and comprehensive information on the range of vertebrate and invertebrate hosts (vectors) are scarce. The molecular approaches employed for the detection of these parasites have uncovered an increasing diversity of species and phylogenetic relationships. Conventional PCR methods (cPCR) combined with DNA sequencing, which have replaced traditional morphological taxonomic parameters, which are dependent on laborious microscopy and cultures, have some limitations: in general, they detect only the predominant taxon (DNA sequence), requiring a lot of work in cloning/sequencing a large number of clones for an appraisal of the whole genetic diversity, thus making this technique limited for mixed infections. The next-generation sequencing (NGS)-based metabarcoding method reduces such limitations, using taxon-specific primers (families, genera or species) to amplify with high sensitivity DNAs from different parasites mixed in a single sample, which are then sequenced on a large scale. Therefore, this approach can virtually identify all species of the selected taxonomic groups. The objective of this study is to analyze the diversity, infer phylogeography and contribute to the taxonomy of trypanosomes and hemogregarines of hosts inhabiting aquatic/semiaquatic environments (anurans and fish), and their vectors (leeches), from African and American (South America) continents. For these purposes, in addition to integrative taxonomy based on morphology combined with DNA barcoding, the present study aims to standardize, and use in field surveys, different molecular methods: 1) Metabarcoding with the aid of next-generation sequencing (NGS); 2) Fluorescent Fragment Length Barcoding (FFLB) for screening of parasites; 3) Analysis of mitochondrial genes (COI, COIII, CytB) obtained by PCR and Nested-PCR for hemogregarines; and 4) Traditional barcoding based on SSU rRNA sequences for both parasites, and gGAPDH sequences for trypanosomes, employing Nested-PCR, amplicon cloning and sequencing to evaluate mixed infections. | |
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